JP6651785B2 - Granular material storage method, granular material storage and transport container, and extrusion molding method using them - Google Patents

Description

  The present invention relates to a method for storing granules, a container for storing and transporting granules, and an extrusion method using the same.

  Polycarbonate resins have many excellent properties, such as excellent heat resistance and mechanical properties, and high dimensional accuracy, and are widely used in a wide variety of fields. However, with the increasing use of light incident on a polycarbonate resin molded article (hereinafter simply referred to as [molded article]) such as a light guide plate in parallel to a plane, there has been no problem with transparency in the past. Has become apparent. That is, it is conspicuous that the molded product is colored yellow (amber), and it is difficult to use the molded product in a field requiring high transparency as it is.

  In order to solve such a problem, for example, Patent Literature 1 specifies a pretreatment at the time of synthesis of a polycarbonate resin, and Patent Literature 2 and Patent Literature 3 control an oxygen concentration at the time of synthesis. A technique for performing this is disclosed. Patent Literature 4 discloses a technique of blending an antioxidant with a polycarbonate copolymer. Further, in a method for manufacturing an extruded resin processed product, Patent Document 5 discloses a technique of subjecting a resin raw material to deoxygenation by general vacuum drying before extrusion molding. Patent Document 6 discloses a technique for flowing an inert gas into a hopper provided in a molding apparatus.

JP-A-06-145337 JP 05-331277 A JP 2002-533544 A JP-A-06-145492 JP 2009-029031 A JP 2001-088176 A

  However, even if the pretreatment is performed during the synthesis of the polycarbonate resin, or if the oxygen concentration during the synthesis is controlled, or if an antioxidant is blended with the polycarbonate resin, the polycarbonate resin may be synthesized and manufactured after the polycarbonate resin is synthesized and manufactured. If the resin is exposed to the atmosphere, that is, if the particulate matter is exposed to the atmosphere, the dissolved oxygen gas amount of the polycarbonate resin increases until it is actually used for molding. The amount of gas increases and the optimal amount of antioxidant changes. That is, even if an amount of an antioxidant sufficient for molding immediately after production is added, the amount of the antioxidant becomes insufficient after standing in the air after production, and the polycarbonate resin is colored. On the other hand, if a sufficient amount is added after a long period of time after production, an excessive amount will be obtained when molding is performed immediately after production, which will cause adhesion to a mold or a transfer roll (mold deposit) and cause an additive. This impairs transparency. Even if the resin raw material (granules) is deoxygenated immediately before extrusion molding, or if the inert gas is flowed into a hopper provided in the molding apparatus, the polycarbonate resin once increased in the storage ( It is difficult to reduce the amount of dissolved oxygen gas in the particulate matter). The present inventor found that even when molding was performed based on the polycarbonate resin while the amount of dissolved oxygen gas of the polycarbonate resin (granules) was large, the obtained molded product was noticeably yellow (amber) in color. It has become clear from these studies. For example, FIG. 7.128, page 323 of Seika Honma, “Polycarbonate Resin Handbook”, shows the oxygen absorption of the polycarbonate resin by the heat treatment at 140 ° C. The drying temperature of the polycarbonate resin before molding is 120 ° C., and it is generally understood that oxygen is taken into the resin by drying before molding. These measuring methods are described in Journal of Applied Polymer Science Vol. 10 P843-857, which measures the increase in mass using a thermobalance.

  Even when an acrylonitrile resin or a cycloolefin polymer-based resin is used in addition to the polycarbonate resin, the obtained molded product is often repeatedly colored yellow (amber).

  Therefore, an object of the present invention is to provide a method for storing granular materials that can surely prevent an increase in the amount of dissolved oxygen gas in the granular materials, and a granular material storage device suitable for performing the storage method.

In order to solve the above-mentioned problems, a container for storing and transporting particulate matter of the present invention is shown below.
(1)
Inert gas inlet pipe,
It is equipped with an inert gas discharge pipe and a mechanism and device for sealing each of them, and when granular material is filled in a closed container, it is transported with inert gas injected and stored. And transport containers.
(2) The method is characterized in that, when filling the inside of the closed container with the opening part opened with the particulate matter, the particulate matter is filled while introducing an inert gas through an inert gas introduction pipe. A) a storage and transport container for granules according to the above.
(3) When the inert gas introduction pipe and the inert gas discharge pipe are installed and the inside of the closed container is filled with the particulate matter by the method described in (2), the opening is closed, and Inert gas is introduced into the closed vessel through the active gas inlet pipe, and the inert gas introduced into the closed vessel is discharged through the inert gas discharge pipe. Purging with a gas, then closing the inert gas introduction pipe and the inert gas discharge pipe from the closed vessel, and closing the opening of the closed vessel, storing and transporting the particulate matter according to (1). container.
(4) A sealed container having an oxygen permeability of 100 cm ³ / (m ² · 24 h · atm) or less and a water vapor permeability at 40 ° C. and 90% RH of 0.1 g / (m ² · 24 hours) or less Use
With the inside of the closed vessel filled with a particulate matter having a dissolved oxygen gas amount of 0.015 cm ³ or less per gram of the particulate matter, the opening is temporarily closed, and the oxygen gas concentration in the atmosphere inside the closed vessel is 2 volumes. %, Wherein the opening of the sealed container is closed in a state of not more than%.
(5) With the inside of the closed container filled with a particulate matter having a water content of 2 × 10 ² ppm or less, the opening is temporarily closed, and the total moisture content of the atmosphere inside the closed container is calculated per 1 gram of the granular material. The container for storing and transporting particulate matter according to (1), wherein the opening of the closed container is closed in a state of 0.2 mg or less.
(6) A method for storing granular materials, wherein an inert gas introduced into a closed container is discharged to an inert gas disposal section through an inert gas discharge pipe in a reduced pressure state.
(7) The container for storing and transporting particulate matter according to (1), wherein an oxygen gas absorbent is enclosed inside the closed container.
(8) The container for storing and transporting particulate matter according to (1) or (7), wherein the pressure inside the closed container is set to 1.3 × 10 ⁴ Pa or less.
(9) The container for storing and transporting particulate matter according to any one of (1) to (7), wherein the closed container is a metal container made of a SUS-based metal.
(10) The container for storing and transporting granules according to (1) to (7), wherein the granules are made of a polycarbonate resin.
(11) A method for producing a polycarbonate resin sheet or film produced by a melt extrusion molding method using the raw materials transported by the container for storing and transporting particulate matter according to (10).
(12) An inert gas is inserted into a raw material supply hopper installed immediately above an extruder, and molding is performed while controlling the oxygen concentration in the hopper at 2.0 × 10 ³ ppm or less (11). A method for producing a sheet or film produced by the method described in (1).
(13) The method according to (12), wherein, when supplying the raw material to the hopper, the container for storing and transporting the granular material is opened while inserting an inert gas into the container for storing and transporting the granular material of the present invention. A method for producing a sheet or film.

  In the granular material storage and transport container of the present invention, the closed space between the inert gas introduction pipe and the inert gas discharge pipe and the opening is sealed in a sealed container into which the raw material is charged through the opening, and the granular material is stored in the closed container. A temporary closing device for temporarily closing the opening of the sealed container filled with the substance, and furthermore, when the particulate matter is filled in the closed container, the inert gas introduction pipe provided in the inert gas introduction pipe is provided. Section and the inert gas discharge section provided in the inert gas discharge pipe are placed in a non-exposed state by the particulate matter, so that the inside of the closed container can be reliably and quickly converted to the inert gas. Can be replaced.

  Further, in the method for storing particulate matter according to the present invention, since the closed vessel is closed after replacing the inside of the closed vessel with the inert gas, it is possible to reliably prevent an increase in the amount of dissolved oxygen gas in the particulate matter. . Therefore, when molding using such a granular material, a granular material having a small amount of dissolved oxygen gas can be used as a raw material. For example, yellow (amber) coloring is negligibly small and extremely small. A molded article made of a thermoplastic resin having high transparency can be obtained.

Schematic explanatory diagram showing the present invention Schematic explanatory diagram showing the present invention Schematic explanatory diagram showing the present invention Schematic explanatory diagram showing the present invention

An example of the best embodiment of the present invention will be described below with reference to FIGS. The following embodiments do not limit the scope of the present invention. That is, those skilled in the art can employ other embodiments within the scope of the principle of the present invention.

(Container structure)
The container has a pellet inlet and a pellet extraction tube, and has an opening / closing valve in the middle of the extraction tube. It is necessary that the inside of the container is filled with the pellets in a clean state, and after the pellets are sealed, it is necessary that the inside of the container is shielded so that foreign substances do not enter from outside.
The inert gas is supplied from a nitrogen tank filled with high-pressure nitrogen gas through a pipe, and is supplied from an inert gas introduction pipe installed in a pellet extraction pipe below the container. The container is provided with an inert gas discharge pipe, and the inside of the container is evacuated from the opening to replace the air with the inert gas. The inert gas introduction pipe and the inert gas discharge pipe may be made of a metal or alloy such as iron, stainless steel, or brass. An inert gas is introduced into the closed container from the inert gas source via a pipe, an inert gas introduction pipe, a plurality of through holes and slits. The inert gas discharged from the discharge pipe is collected by an inert gas source as necessary. Further, a filter having an appropriate size may be provided so that the particulate matter is not discharged.
Although not limited, an inert gas introduction pipe and an exhaust pipe are arranged at distant positions inside the container. Further, it is more preferable that the inert gas introduction pipe and the discharge pipe are arranged so as to be located farthest from each other inside the container or as far as possible.
Furthermore, in the method for storing and transporting granular materials of the present invention including the preferred embodiments and configurations described above, a configuration in which an oxygen gas absorbent is installed inside the container can be adopted. In addition, as a configuration in which the oxygen gas absorbent is enclosed in the closed container, for example, for 1 kg of the granular material stored in the closed container, the oxygen gas absorbent (for example, Mitsubishi Gas Chemical Co., Ltd.) And two oxygen absorbers (RP-20A). It is preferable to adjust the filling amount in accordance with the atmosphere inside the closed container so that oxygen remaining as a gas phase in the closed container can be reliably absorbed.
Here, the oxygen gas absorbent may be in the form of an iron oxide-based oxygen gas absorbent, or may be in the form of an organic compound-based oxygen gas absorbent. Specific examples of the iron oxide-based oxygen gas absorbent from which iron chemically reacts with oxygen to deoxygenate include Ageless manufactured by Mitsubishi Gas Chemical Co., Ltd. The iron oxide-based oxygen gas absorbent includes a moisture-dependent FX type that starts oxygen absorption upon contact with moisture present in the environment, a self-reactive SA type, a Z-PT type, and an E type. Specific examples of the organic compound-based oxygen gas absorbent from which ascorbic acid and catechol react with oxygen to deoxygenate include Ageless manufactured by Mitsubishi Gas Chemical Co., Ltd., and there is a GL type which is a self-reaction type. . Further, for the purpose of preventing oxidation, moisture absorption and discoloration of metal and electronic parts, it is possible to use an RP system manufactured by Mitsubishi Gas Chemical Company, Ltd. By enclosing the oxygen gas absorbent inside the closed container, the inside of the closed container can be more reliably set as an oxygen-free and anhydrous environment. Various products are distributed depending on the amount of absorption.

(Container material)
The container is generally made of stainless steel or iron and has a size of about 6 m long × 2.4 m wide × 2.6 m high. An inner bag such as a polyethylene film may be attached. However, it has a volume that is not too large so that the gas replacement time is not too long. Further, it has a pressure resistance enough to withstand the outside atmospheric pressure even when the inside is evacuated.
The thickness and the degree of flexibility may be such that the openings of the inert gas introduction pipe and the inert gas discharge pipe can be temporarily closed (closed). The inert gas introduction pipe and the inert gas discharge pipe may be made of metal (for example, iron or aluminum), alloy (for example, stainless steel, aluminum alloy, brass), or plastic.

(Inert gas supply means)
An inert gas is supplied from when the pellets are filled in the container. Close the pellet inlet, open the inert gas exhaust port, supply the inert gas from the pellet extraction pipe below the container through the pipe from the tank filled with the inert gas at high pressure, and exhaust the gas above the container. Air is exhausted from the mouth into the container, and the inside of the container is replaced with air by an inert gas.
The inert gas introduction pipe and the inert gas discharge pipe may be made of a metal or alloy such as iron, stainless steel, or brass. An inert gas is introduced into the closed container from the inert gas source via a pipe, an inert gas introduction pipe, a plurality of through holes and slits. The inert gas discharged from the discharge pipe is collected by an inert gas source as necessary. Further, a filter having an appropriate size may be provided so that the particulate matter is not discharged.
When nitrogen gas is injected into the container, the air in the container is pushed out and exhausted from the exhaust pipe. The oxygen concentration of the exhausted air is measured by an oximeter. When the oxygen concentration becomes 2.0% by volume or less, it is assumed that the inside of the container is under an inert gas atmosphere. After the inside of the container is under an inert gas (nitrogen gas) atmosphere, the injection of the nitrogen gas is stopped, and the exhaust gas outlet of the inert gas is hermetically closed.
In the method for storing particulate matter according to the present invention, the inside of the closed vessel is filled with the particulate matter having a dissolved oxygen gas amount of 0.015 cm ³ or less per gram of the particulate matter, and the opening is closed. With the oxygen gas concentration of the internal atmosphere set to 2.0% by volume or less, preferably 1.5% by volume or less, more preferably 1% by volume (1.0 × 103 ppm) or less, close the opening of the closed container. It can be taken as a form.

(Type and properties of inert gas)
Examples of the inert gas include nitrogen gas, carbon dioxide gas, argon, helium, and the like, and the use of nitrogen gas is preferred from the economical viewpoint. When nitrogen gas is used as the inert gas, a commercially available nitrogen gas cylinder or the like can be used as the inert gas source.However, from the viewpoint that replacement of the cylinder and the like is complicated and economical, low-cost and simple inert gas is used. As a source, it is desirable to use a separation membrane type or PSA type nitrogen gas generator. On the other hand, in consideration of removing oxygen from the environment, it is preferable to use a cylinder having high nitrogen gas purity.

(Granular)
In the method for storing the granular material of the present invention including the various preferable forms and configurations described above, or in the granular material storage device of the present invention including the various preferable forms and structures described above, the granular material is used. Specific examples thereof include a thermoplastic resin, more specifically, thermoplastic resin pellets and flakes, and examples thereof include a polycarbonate resin and a cycloolefin polymer-based resin. The shape of the granular material may be a pellet, a sphere, a disk, or the like.
Polycarbonate can be synthesized based on a known method, and examples thereof include various synthesis methods including an interfacial polymerization method, a pyridine method, a transesterification method, and a ring-opening polymerization method of a cyclic carbonate compound. Specifically, an aromatic dihydroxy compound or a small amount thereof and a polyhydroxy compound, carbonyl chloride generally known as phosgene, or a carbonic diester represented by dimethyl carbonate or diphenyl carbonate, carbon monoxide or carbon dioxide It is a polymer or copolymer of a thermoplastic aromatic polycarbonate, which may be linear or branched, obtained by reacting the above carbonyl compound.

  As the aromatic dihydroxy compound as a raw material, for example, 2,2-bis (4-hydroxyphenyl) propane [= bisphenol A], 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 2,2 -Bis (4-hydroxy-3,5-diethylphenyl) propane, 2,2-bis (4-hydroxy- (3,5-diphenyl) phenyl) propane, 2,2-bis (4-hydroxy-3,5 -Dibromophenyl) propane, 2,2-bis (4-hydroxyphenyl) pentane, 2,4'-dihydroxy-diphenylmethane, bis- (4-hydroxyphenyl) methane, bis- (4-hydroxy-5-nitrophenyl) Methane, 1,1-bis (4-hydroxyphenyl) ethane, 3,3-bis (4-hydroxyphenyl) pentane, 1, -Bis (4-hydroxyphenyl) cyclohexane, bis (4-hydroxyphenyl) sulfone, 2,4'-dihydroxydiphenylsulfone, bis (4-hydroxyphenyl) sulfide, 4,4'-dihydroxydiphenylether, 4,4'- Dihydroxy-3,3'-dichlorodiphenyl ether, 4,4'-dihydroxy-2,5-diethoxydiphenyl ether, 1-phenyl-1,1-bis (4-hydroxyphenyl) ethane, 1,1-bis (4- Hydroxy-3-methylphenyl) cyclohexane, 1-phenyl-1,1-bis (4-hydroxy-3-methylphenyl) ethane and the like can be mentioned, and preferably, bis (4-hydroxyphenyl) alkanes are used. And particularly preferably 2,2-bis (4-hydroxy Eniru) propane [referred to as bisphenol A]. These aromatic dihydroxy compounds can be used alone or in combination of two or more.

  To obtain a branched polycarbonate, phloroglucin, 4,6-dimethyl-2,4,6-tris (4-hydroxyphenyl) heptene-2,4,6-dimethyl-2,4,6-tris (4-hydroxy Phenyl) heptane, 2,6-dimethyl-2,4,6-tris (4-hydroxyphenyl) heptene-3,1,3,5-tris (4-hydroxyphenyl) benzene, 1,1,1-tris ( Polyhydroxy compounds represented by 4-hydroxyphenyl) ethane or the like, or 3,3 bis (4-hydroxyaryl) oxindole (= isatin bisphenol), 5-chlorisatin bisphenol, 5,7-dichlorisatin bisphenol , 5-bromoisatin bisphenol or the like is used as a part of the above-mentioned aromatic dihydroxy compound. Well, usage, 0.01 to 10 mol%, preferably from 0.1 to 2 mol%.

  In the reaction by the interfacial polymerization method, the pH is usually maintained at 10 or more in the presence of an organic solvent or an aqueous alkali solution inert to the reaction, and an aromatic dihydroxy compound and a molecular weight modifier (terminal terminator), if necessary. After reacting with phosgene using an antioxidant to prevent oxidation of the aromatic dihydroxy compound, a polymerization catalyst such as a tertiary amine or a quaternary ammonium salt is added, and the interfacial polymerization is performed to form the polycarbonate. Obtainable. The addition of the molecular weight modifier is not particularly limited as long as it is between the time of phosgenation and the start of the polymerization reaction. The reaction temperature is 0 to 35 ° C., and the reaction time is several minutes to several hours.

  Here, examples of the organic solvent inert to the reaction include chlorinated hydrocarbons such as dichloromethane, 1,2-dichloroethane, chloroform, monochlorobenzene, and dichlorobenzene, and aromatic hydrocarbons such as benzene, toluene, and xylene. be able to. Examples of the molecular weight regulator or the terminal terminator include compounds having a monovalent phenolic hydroxyl group, and specific examples thereof include m-methylphenol, p-methylphenol, m-propylphenol, p-propylphenol, and p-propylphenol. -Tert-butylphenol, p-long-chain alkyl-substituted phenol and the like. Tertiary amines such as trimethylamine, triethylamine, tributylamine, tripropylamine, trihexylamine and pyridine; and quaternary ammonium salts such as trimethylbenzylammonium chloride, tetramethylammonium chloride and triethylbenzylammonium chloride. Can be mentioned.

  The transesterification reaction is a transesterification reaction between a carbonic acid diester and an aromatic dihydroxy compound. Usually, by adjusting the mixing ratio between the carbonic acid diester and the aromatic dihydroxy compound or the degree of pressure reduction during the reaction, the desired molecular weight of the polycarbonate and the amount of terminal hydroxyl groups are determined. The terminal hydroxyl group content has a significant effect on the heat stability, hydrolysis stability, color tone, and the like of the polycarbonate, and is preferably 1,000 ppm or less, particularly preferably 700 ppm or less, in order to have practical physical properties. It is common to use an equimolar amount or more of a carbonic acid diester with respect to 1 mole of the aromatic dihydroxy compound, and preferably 1.01 to 1.30 moles.

When synthesizing polycarbonate by the transesterification method, a transesterification catalyst is usually used. Although there is no particular limitation on the transesterification catalyst, an alkali metal compound and / or an alkaline earth metal compound are mainly used, and a basic boron compound, a basic phosphorus compound, a basic ammonium compound, or an amine-based compound are mainly used. It is also possible to use a basic compound such as a compound in combination. In the transesterification reaction using such a raw material, the reaction is carried out at a temperature of 100 to 320 ° C., and finally, under a reduced pressure of 2.7 × 10 ² Pa ( ² mmHg) or less, an aromatic hydroxy compound or the like A method of performing a melt polycondensation reaction while removing a product is included. The melt polycondensation can be carried out batchwise or continuously. However, in the case of polycarbonate suitable for use in the present invention, it is preferable to carry out the continuous polycondensation from the viewpoint of stability and the like. In the transesterification method, it is preferable to use, as a catalyst deactivator in the polycarbonate, a compound that neutralizes the catalyst, for example, a sulfur-containing acidic compound, or a derivative formed therefrom. It is added in an amount of 0.5 to 10 equivalents, preferably 1 to 5 equivalents to the metal, and usually 1 to 100 ppm, preferably 1 to 20 ppm, based on the polycarbonate.

  After isolating the obtained polycarbonate based on a known method, for example, a known strand-type cold cut method (a polycarbonate resin once melted is formed into a strand, cooled, cut into a predetermined shape, and pelletized. Method), hot cut method in air (cutting polycarbonate resin once melted into pellets without contact with water in the air), hot cut method in water hot cut method (once melting) The polycarbonate resin pellets can be obtained by a method in which the polycarbonate resin thus cut is cut in water, and simultaneously cooled and pelletized. In addition, it is preferable that the obtained polycarbonate resin pellets are dried based on a method such as drying using a hot air drying oven, a vacuum drying oven, or a dehumidifying drying oven, if necessary. The shape of the pellet is essentially arbitrary, and examples thereof include a cylindrical shape, a stone shape, a spherical shape, and a cubic shape. Granules made of other thermoplastic resins can be produced in a similar manner.

The cycloolefin polymer-based resin can be produced based on a known method, for example, a production method such as performing ring-opening polymerization of a monomer in an organic solvent in the presence of a metathesis catalyst.
Examples of the monomer of the cycloolefin polymer resin include cyclopentadiene, cyclopentadiene trimer, tetracyclododecene, alkyl-substituted tetracyclododecene, alkylidene-substituted tetracyclododecene, norbornene, alkyl-substituted norbornene, and alkylidene group Substituted norbornene and the like can be mentioned.
These can be used alone or in combination of several or more.
Further, cyclobutene, cyclopentene, cycloheptene, cyclooctene, cycloolefins such as dicyclopentadiene, ethylene, propylene, olefinic compounds such as butene, 4-vinylcyclohexene, vinyl cyclic hydrocarbon compounds such as 4-vinylcyclohexane, styrene, It may be copolymerized with a styrene compound such as α-methylstyrene or an acrylate compound such as methyl methacrylate.

The thermoplastic resin (granules) may contain 0.02% by mass to 1% by mass of an antioxidant. Here, examples of the antioxidant include phenol antioxidants, hindered phenol antioxidants, bisphenol antioxidants, polyphenol antioxidants, organic sulfur compounds, and organic phosphorus compounds such as phosphite. . Specifically, as a phenolic antioxidant, 2,6-di-butyl-4-methylphenol, n-octadecyl-3- (3 ′, 5′-di-tert-butyl-4′-hydroxyphenyl) Propionate, tetrakis [methylene-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] methane, tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, 4, 4'-butylidenebis- (3-methyl-6-tert-butylphenol), triethylene glycol-bis [3- (3-tert-butyl-hydroxy-5-methylphenyl) propionate], 3,9-bis {2- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethyl Tilethyl {-2,4,8,10-tetraoxaspiro [5,5] undecane. Examples of hindered phenolic antioxidants include pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] and octadecyl-3- (3,5-di-tert. -Butyl-4-hydroxyphenyl) propionate, thiodiethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], N, N'-hexane-1,6-diylbis [3- (3,5-di-tert-butyl-4-hydroxyphenylpropionamide), 2,4-dimethyl-6- (1-methylpentadecyl) phenol, diethyl [[3,5-bis (1,1-dimethyl) Ethyl) -4-hydroxyphenyl] methyl] phosphoate, 3,3 ′, 3 ″, 5,5 ′, 5 ″ -hexa-tert- Tyl-a, a ', a "-(mesitylene-2,4,6-triyl) tri-p-cresol, 4,6-bis (octylthiomethyl) -o-cresol, ethylenebis (oxyethylene) bis [ 3- (5-tert-butyl-4-hydroxy-m-tolyl) propionate], hexamethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 1,3,5 -Tris (3,5-di-tert-butyl-4-hydroxybenzyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, 2,6-di-tert- Butyl-4- (4,6-bis (octylthio) -1,3,5-triazin-2-ylamino) phenol and the like can be mentioned.
In the granular material of the present invention, in addition to the antioxidant, as additives, phenol-based, phosphorus-based, and sulfur-based heat stabilizers; benzotriazole-based and benzophenone-based ultraviolet absorbers; carboxylic acid esters and polysiloxane compounds , A release agent such as paraffin wax (polyolefin) or polycaprolactone; an antistatic agent or the like may be added.

  As a heat stabilizer, a phosphite compound (a) in which at least one ester in a molecule is esterified with phenol and / or phenol having at least one alkyl group having 1 to 25 carbon atoms, phosphorous acid (b) ) And tetrakis (2,4-di-tert-butylphenyl) -4,4′-biphenylene-di-phosphonite (c). Specific examples of the phosphite compound (a) include trioctyl phosphite, tridecyl phosphite, triphenyl phosphite, trisnonylphenyl phosphite, tris (octylphenyl) phosphite, tris (2,4-di- tert-butylphenyl) phosphite, tridecyl phosphite, didecyl monophenyl phosphite, dioctyl monophenyl phosphite, diisopropyl monophenyl phosphite, monobutyl diphenyl phosphite, monodecyl diphenyl phosphite, monooctyl diphenyl phosphite, Distearyl pentaerythritol diphosphite, diphenylpentaerythritol diphosphite, bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite Phyte, 2,2-methylenebis (4,6-di-tert-butylphenyl) octyl phosphite, bis (nonylphenyl) pentaerythritol diphosphite, bis (2,4-di-tert-butylphenyl) pentaerythritol Examples thereof include phosphite and bis (2,6-di-tert-butyl-4-ethylphenyl) pentaerythritol diphosphite. These may be used alone or as a mixture of two or more.

  Examples of the release agent include at least one compound selected from the group consisting of an aliphatic carboxylic acid, an ester of an aliphatic carboxylic acid and an alcohol, an aliphatic hydrocarbon compound having a number average molecular weight of 200 to 15,000, and a polysiloxane-based silicone oil. be able to. Examples of the aliphatic carboxylic acid include a saturated or unsaturated aliphatic monovalent, divalent or trivalent carboxylic acid. Here, the aliphatic carboxylic acid also includes an alicyclic carboxylic acid. Among these, preferred aliphatic carboxylic acids are monovalent or divalent carboxylic acids having 6 to 36 carbon atoms, and more preferred are aliphatic saturated monovalent carboxylic acids having 6 to 36 carbon atoms. Specific examples of the aliphatic carboxylic acid, palmitic acid, stearic acid, caproic acid, capric acid, lauric acid, arachinic acid, behenic acid, lignoceric acid, cerotic acid, melicic acid, tetraliacontanic acid, montanic acid, adipic acid, Azelaic acid and the like can be mentioned. As the aliphatic carboxylic acid in the ester of the aliphatic carboxylic acid and the alcohol, the same aliphatic carboxylic acids as those described above can be used. On the other hand, examples of the alcohol include a saturated or unsaturated monohydric or polyhydric alcohol. These alcohols may have a substituent such as a fluorine atom or an aryl group. Among these, a monovalent or polyhydric saturated alcohol having 30 or less carbon atoms is preferable, and an aliphatic saturated monohydric alcohol or polyhydric alcohol having 30 carbon atoms or less is more preferable. Here, the aliphatic includes an alicyclic compound. Specific examples of alcohol include octanol, decanol, dodecanol, stearyl alcohol, behenyl alcohol, ethylene glycol, diethylene glycol, glycerin, pentaerythritol, 2,2-dihydroxyperfluoropropanol, neopentylene glycol, ditrimethylolpropane, dipentaerythritol and the like. be able to. The ester compound may contain an aliphatic carboxylic acid and / or an alcohol as impurities, or may be a mixture of a plurality of compounds. Specific examples of the ester of an aliphatic carboxylic acid and an alcohol include beeswax (a mixture containing myristyl palmitate as a main component), stearyl stearate, behenyl behenate, stearyl behenate, glycerin monopalmitate, and glycerin monostearate. Glycerin distearate, glycerin tristearate, pentaerythritol monopalmitate, pentaerythritol monostearate, pentaerythritol distearate, pentaerythritol tristearate, pentaerythritol tetrastearate and the like. Examples of the aliphatic hydrocarbon having a number average molecular weight of 200 to 15,000 include liquid paraffin, paraffin wax, microwax, polyethylene wax, Fischer-Tropsch wax, and α-olefin oligomers having 3 to 12 carbon atoms. Here, the aliphatic hydrocarbon includes an alicyclic hydrocarbon. These hydrocarbon compounds may be partially oxidized. Among these, paraffin wax, polyethylene wax or partial oxides of polyethylene wax are preferred, and paraffin wax and polyethylene wax are more preferred. The number average molecular weight is preferably from 200 to 5,000. These aliphatic hydrocarbons may be a single substance or a mixture of various components and various molecular weights, provided that the main component is within the above range. Examples of the polysiloxane-based silicone oil include dimethyl silicone oil, phenylmethyl silicone oil, diphenyl silicone oil, and fluorinated alkyl silicone. Two or more of these may be used in combination.

  Specific examples of the ultraviolet absorber include inorganic ultraviolet absorbers such as cerium oxide and zinc oxide, and organic ultraviolet absorbers such as benzotriazole compounds, benzophenone compounds, and triazine compounds. Among these, an organic ultraviolet absorber is preferred. In particular, benzotriazole compounds, 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5-[(hexyl) oxy] -phenol, 2- [4,6-bis (2, 4-dimethylphenyl) -1,3,5-triazin-2-yl] -5- (octyloxy) phenol, 2,2 ′-(1,4-phenylene) bis [4H-3,1-benzoxazine-4- ON], and at least one selected from the group consisting of [(4-methoxyphenyl) -methylene] -propanedioic acid-dimethyl ester. Specific examples of the benzotriazole compound include a condensate of methyl-3- [3-tert-butyl-5- (2H-benzotriazol-2-yl) -4-hydroxyphenyl] propionate-polyethylene glycol. . Further, specific examples of other benzotriazole compounds include 2-bis (5-methyl-2-hydroxyphenyl) benzotriazole, 2- (3,5-di-tert-butyl-2-hydroxyphenyl) benzotriazole, -(3 ', 5'-di-tert-butyl-2'-hydroxyphenyl) -5-chlorobenzotriazole, 2- (3-tert-butyl-5-methyl-2-hydroxyphenyl) -5-chlorobenzo Triazole, 2- (2'-hydroxy-5'-tert-octylphenyl) benzotriazole, 2- (3,5-di-tert-amyl-2-hydroxyphenyl) benzotriazole, 2- [2-hydroxy-3 , 5-Bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 2,2′-methyl 2-bis [4- (1,1,3,3-tetramethylbutyl) -6- (2N-benzotriazol-2-yl) phenol] [methyl-3- [3-tert-butyl-5- (2H- Benzotriazol-2-yl) -4-hydroxyphenyl] propionate-polyethylene glycol] condensate. Two or more of these may be used in combination. Among the above, preferably, 2- (2′-hydroxy-5′-tert-octylphenyl) benzotriazole, 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl]- 2H-benzotriazole, 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5-[(hexyl) oxy] -phenol, 2- [4,6-bis (2,4 -Dimethylphenyl) -1,3,5-triazin-2-yl] -5- (octyloxy) phenol, 2,2'-methylene-bis [4- (1,1,3,3-tetramethylbutyl)- 6- (2N-benzotriazol-2-yl) phenol].

  Examples of the light stabilizer include a benzotriazole-based UV absorber, a benzophenone-based UV absorber, a triazine-based UV absorber, an ogganilide-based UV absorber, a malonic ester-based UV absorber, and a hindered amine. Specific examples of the light stabilizer include, for example, 2,2-methylenebis [4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol], 2- ( 2-hydroxy-5-tert-octylphenyl) benzotriazole, 2- (3-tert-butyl-5-methyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (5-methyl-2-hydroxyphenyl) ) Benzotriazole, 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 2,2′-methylenebis (4-cumyl-6-benzotriazolephenyl), p-phenylenebis (1,3-benzoxazin-4-one), [(4-methoxyphenyl) -methylene] -dimethyl malonate And the like.

(Method of measuring dissolved oxygen)
In the method for storing a granular material of the present invention including the various preferred embodiments and configurations described above, as a method for measuring the dissolved oxygen gas amount of the granular material, the saturated dissolved oxygen amount of the granular material is measured by a change in mass, and measured. A method for determining based on a comparison with a change in mass when saturated absorption of dissolved oxygen into a sample, dissolving particulate matter in a deoxygenated organic solvent such as methylene chloride, dissolving dissolved oxygen in the solvent, A method of directly measuring the oxygen concentration with a dissolved oxygen meter for organic solvents, heating a polymer solution obtained by dissolving particulate matter in methylene chloride or the like in nitrogen gas, or bubbling with nitrogen gas to remove oxygen. A method of releasing it into the atmosphere and quantifying it with an oxygen detection liquid can be mentioned (for example, Journal of Applied Polymer Science). ce Vol.10 P843-857). Alternatively, using a fully automatic thermal desorption spectrometer TPD-MASS (TPD-1-AT) manufactured by Nippon Bell Co., Ltd., a sample having a mass of 1.2 g is sampled with He gas (gas flow rate of 50 cc / min.) As a carrier gas. )), A method of raising the temperature from 30 ° C. to 150 ° C. at a rate of 10 ° C./min, holding the temperature for 30 minutes, and quantifying the amount of oxygen discharged during that time.

  The oxygen transmission rate (oxygen transmission rate per unit thickness) can be determined by a differential pressure method specified in JIS K7126-1 or an equal pressure method specified in JISK7126-1. The differential pressure method is a method in which a gas is introduced into one side through a film, the other side is evacuated, and the pressure rise on the vacuum side is measured with a mercury manometer or a pressure sensor to measure the transmission speed. The isobaric method is a method in which the total pressure on both sides of a film is made equal, and the amount of permeation based on the partial pressure difference of the gas to be measured is detected using a gas chromatography or a sensor to measure the permeation speed.

(Pellet transfer method)
After connecting the pellet extraction pipe of the oxygen-free container and the hopper of the extruder with a metal pipe and a metal flexible pipe, inject the inert gas into the hopper immediately above the extruder and sufficiently displace it from the air. The pellet is transferred to the hopper of the extruder by introducing an inert gas from the insertion pipe, opening the valve of the pellet extraction pipe, and then opening the inert gas discharge pipe. Sufficient replacement with an inert gas means that the oxygen concentration in the hopper is 2.0% by volume or less.
Also, when the oxygen-free container is at a position sufficiently higher than the hopper of the extruder, it can be completely transferred by gravity, but when it cannot be completely transferred by gravity, it is pumped using inert gas. Alternatively, an air delivery method can be used.

(Extrusion molding)
A molded article can be formed by an extrusion molding method using the thermoplastic resin pellets, which are raw materials stored in the container for storing and transporting the granular material of the present invention.

Here, such an extrusion molding method is an extrusion molding method of a thermoplastic resin to melt and extrude thermoplastic resin pellets as a raw material using an extruder,
The present invention is characterized in that a granular material (raw material thermoplastic resin pellet) packaged by the method for storing and transporting granular material of the present invention is used as a raw material.

Here, the extruder is
(A) a heating cylinder (also referred to as a barrel) for plasticizing and melting raw material thermoplastic resin pellets having a die, and
(B) a hopper attached to the heating cylinder to supply the raw material thermoplastic resin pellets to the heating cylinder;
It has. Incidentally, when the surface of the extruded sheet or film is required to be smooth, the extruder further includes:
(C) a plurality of mirror-finished rolls for transferring a smooth surface, and
(D) It is preferable to include a device for attaching a protective film, a device for cutting to a predetermined length, or a winding device as necessary. Then, the atmosphere in the hopper into which the raw material thermoplastic resin pellets are charged may be set to an oxygen gas concentration of 2.0% by volume (2.0 × 10 ³ ppm) or less. Further, the pressure in the hopper into which the raw material thermoplastic resin pellets are charged can be set to 1.3 × 10 ⁴ Pa or less.

The extruder is
(A) having a die, a heating cylinder for plasticizing and melting raw material thermoplastic resin pellets, and
(B) a hopper attached to the heating cylinder, for supplying the raw material thermoplastic resin pellets to the heating cylinder; An exhaust port (vent portion) is provided in the heating cylinder, and the atmosphere in the heating cylinder when plasticizing and melting the raw material thermoplastic resin pellets is set to an oxygen gas concentration of 2 × 10 ³ ppm or less. It can be in the form. Alternatively, an exhaust port (vent) is provided in the heating cylinder, and the pressure in the heating cylinder when plasticizing and melting the raw material thermoplastic resin pellets is set to 1.3 × 10 ⁴ Pa or less. It can be.

  Here, as the extruder, a well-known single-screw extruder including a vent-type extruder or a tandem-type extruder, or a well-known twin-screw extruder including a parallel-type twin-screw extruder or a conical-type twin-screw extruder may be used. Yes, and the structure, configuration, and type of die are essentially arbitrary. The heating cylinder generally includes a supply section (feed zone), a compression section (compression zone), and a metering section (metering zone). A die is disposed downstream of the metering section, and a hopper is provided in the supply section. Installed. Depending on the extruder used, the heating cylinder may be required to have a closed structure and be modified so that an inert gas can be introduced into the heating cylinder. The raw material thermoplastic resin pellets put into the hopper are sent to the compression unit as a solid in the supply unit of the heating cylinder, and the plasticization and melting of the raw material thermoplastic resin pellets progress before and after the compression unit, and in the measurement unit, It is weighed and extruded through a die. In the case where an exhaust port (vent) is provided, the exhaust port (vent) may be provided in the compression section or downstream thereof (for example, between the compression section and the measuring section). The type, structure, and configuration of the heating cylinder, screw, and hopper are essentially arbitrary, and a known heating cylinder, screw, and hopper can be used. In the case of performing continuous molding, the raw thermoplastic resin pellets need to be sent to the hopper by air, but the loading method can be any method. For example, a method in which the inside of the hopper is set to a negative pressure, and the raw material thermoplastic resin pellets are flown into the hopper from the raw material resin storage section via a pipe (for example, a flow transfer method using nitrogen gas) can be adopted.

The extrusion molding machine further includes, for example,
(C) a source of inert gas, and
(D) piping for introducing an inert gas from an inert gas source into the heating cylinder;
It is preferable to have.

And it is desirable that the piping is attached to a portion upstream of the portion of the heating cylinder to which the hopper is attached. It is preferable that a pressure control valve and a pressure sensor are provided in the middle of the pipe in order to keep the flow rate and the pressure of the inert gas introduced into the heating cylinder constant. With such a configuration, the atmosphere in the hopper into which the raw material thermoplastic resin pellets are charged can be reliably reduced to an oxygen gas concentration of 2 × 10 ³ ppm or less.

It is desirable that the inert gas flows from the inert gas source to the outside of the system via a pipe, a heating cylinder, and a hopper. In addition, it is preferable to make the material flow into and out of the material bunker (storage) from the viewpoint of effectively using the inert gas. In this case, the portion of the heating cylinder through which the inert gas flows is preferably airtight. However, the portion of the heating cylinder through which the inert gas flows does not need to be strictly airtight, and if the pressure of the inert gas in the portion of the heating cylinder through which the inert gas flows is kept substantially constant, There may be some leakage of the inert gas from the portion of the heating cylinder through which the gas flows. In this case, the raw material thermoplastic resin pellets are filled in the hopper, and from the portion of the heating cylinder to which the hopper is attached to the tip of the heating cylinder, the raw material thermoplastic resin pellets are plasticized and inert gas is supplied. Is preferably higher than the atmospheric pressure in the portion of the heating cylinder through which the gas flows. The pressure in the portion of the heating cylinder through which the inert gas flows is preferably, for example, about 2 × 10 ³ Pa (0.02 kgf / cm ² ) or higher than the atmospheric pressure.

Further, in order to reduce the pressure in the hopper into which the raw material thermoplastic resin pellets are charged to 1.3 × 10 ⁴ Pa or less, the inside of the hopper may be evacuated using a vacuum pump.

Further, in order to make the atmosphere in the heating cylinder at the time of plasticizing and melting the raw material thermoplastic resin pellets into an oxygen gas concentration of 2 × 10 ³ ppm or less, the pressure may be reduced and discharged by a vacuum pump, or In addition, nitrogen gas may be introduced while reducing the pressure with a vacuum pump, or a means and measure may be adopted such that sufficient nitrogen gas is substituted.

In order to reduce the pressure in the heating cylinder to 1.3 × 10 ⁴ Pa or less when plasticizing and melting the raw material thermoplastic resin pellets, the pressure may be reduced by a vacuum pump.

  In the granular material storage and transport container of the present invention, the space between the inert gas introduction pipe and the inert gas discharge pipe inserted into the closed container through the opening and the opening is closed, and the granular A closed device that closes the opening of the closed container filled with the substance, and further, in a state where the particulate matter is filled in the closed container, an inert gas introduction unit provided in the inert gas introduction pipe, In addition, since the inert gas discharge portion provided in the inert gas discharge pipe is placed in a non-exposed state by the particulate matter, the inside of the closed container is reliably and quickly replaced with the inert gas. can do.

  Further, in the storage and transport container for granular materials of the present invention, since the closed container is closed after replacing the inside of the closed container with an inert gas, it is possible to surely prevent an increase in the amount of dissolved oxygen gas in the granular material. Can be. Therefore, when molding using such a granular material, a granular material having a small amount of dissolved oxygen gas can be used as a raw material. For example, yellow (amber) coloring is negligibly small and extremely small. A molded article made of a thermoplastic resin having high transparency can be obtained.

  Hereinafter, the present invention will be described based on preferred embodiments with reference to the drawings. However, the present invention is not limited to the embodiments, and various numerical values and materials in the embodiments are examples.

Example 1
Example 1 Example 1 relates to a particulate storage and transport container of the present invention. Example 1 relates to a method for extrusion molding of a thermoplastic resin, and further relates to a first embodiment of an extrusion molding machine. In the following description, the term “granular material” may be replaced with the term “raw material thermoplastic resin pellet” for explanation.

  FIG. 1 shows a conceptual diagram of a closed container and the like for explaining the granular material storage and transport container of the present invention. In these drawings, a part of the closed container is cut out and shown. Also, in these drawings, although a small amount of raw material thermoplastic resin pellets are illustrated as being aligned, in reality, the raw material thermoplastic resin pellets are filled in a sealed container, and in a random state. Is filled.

As shown in FIG. 1, the storage and transport container for the granular material of Example 1 comprises:
Inert gas introduction pipe 71,
An inert gas discharge pipe 73, and
The space between the inert gas introduction pipe 71 and the inert gas discharge pipe 73 connected to the inside of the closed container 60 via the opening 61 and the opening 61 is closed, and the closed container 60 filled with the particulate matter is closed. A temporary closing device 80 for temporarily closing the opening 61 is provided. Then, in a state where the particulate matter is filled in the closed container 60, the inert gas introduction part provided in the inert gas introduction pipe 71 and the inert gas discharge part provided in the inert gas discharge pipe 73 are , Placed unexposed by the granules.

  Specifically, the temporary closing device 80 has a configuration capable of blocking the opening 61 of the closed container 60 from the outside. Here, the pressing member 81 that comes into contact with the opening 61 of the sealed container 60 is made of a flexible material, specifically, an elastic member such as rubber or urethane. The contact portion 82 is attached to the lid-like support member 83 using, for example, an adhesive. By forming the contact portion 82 from a flexible material, the inert gas introduction pipe 71 and the inert gas discharge pipe 73 connected to the inside of the closed container 60 through the opening 61 and the opening 61 Can be reliably sealed.

  The thickness between the contact portion 82 and the degree of flexibility is such that the space between the inert gas introduction pipe 71 and the inert gas discharge pipe 73 connected to the inside of the closed vessel 60 via the opening 61 and the opening 61 is sealed. It is possible to hold the opening 61 of the sealed container 60 temporarily (while keeping it in a sealed state) while maintaining the temporarily closed state of the opening 61 (making it a closed state) with the temporary closing device 80. The thickness and the degree of flexibility that can be achieved are appropriately selected.

  Although not limited, as shown, an inert gas introduction pipe 71 and an inert gas discharge pipe 73 are arranged at separate positions inside the sealed container 60. Further, it is more preferable that the inert gas introduction pipe 71 and the inert gas discharge pipe 73 are arranged so as to be located farthest from each other or as far as possible within the closed vessel 60. .

In the container for storing and transporting the granular material of Example 1, the oxygen permeability was 100 cm ³ / (m ² · 24 h · atm) or less, and the water vapor permeability at 40 ° C. and 90% RH was 0.1 g / ( m ² · 24 hours) using the a closed container 60 below. Specifically, in the first embodiment, the closed container 60 has a structure formed of SUS304, and is more specifically the container shown in FIG.

  Granules used in Example 1 or Examples 2 to 10 to be described later, specifically, raw material thermoplastic resin pellets, more specifically, polycarbonate resin (more specifically, Mitsubishi Engineering Plastics HL-4000). Then, the melted polycarbonate resin was formed into a strand and pelletized based on a cold cut method using a strand cutter. Here, the temperature of the raw thermoplastic resin pellets at this point is about 100 ° C., and at the time of pelletization, the raw thermoplastic resin pellets are in the atmosphere. Thereafter, the pellets were immediately stored in a tank in which the inside was an inert gas atmosphere (specifically, for example, a nitrogen gas atmosphere), and the pellets were cooled.

Then, as shown in FIG. 2, the inside of the closed container 60 is filled with the raw material thermoplastic resin pellets 40. At this time, the amount of dissolved oxygen gas per gram of the raw material thermoplastic resin pellets 40 is 0.015 cm ³ or less, and further, the water content is 2 × 10 ² ppm or less, preferably 1.5 × 10 ² ppm. The inside of the closed container 60 is filled with the raw material thermoplastic resin pellets 40 of less than ppm. That is, immediately after the production of the raw material thermoplastic resin pellets 40, the raw material thermoplastic resin pellets 40 were stored in the closed container 60. At this time, the process may be performed in a state where the inside of the sealed container 60 is filled with an inert gas in advance. Incidentally, after the granulation of the raw material thermoplastic resin pellets 40, the average temperature of the raw material thermoplastic resin pellets 40 up to the filling of the closed vessel 60, 60 ° C or higher, there below the glass transition temperature T _g of the thermoplastic resin In addition, the temperature is set to be equal to or lower than the heat-resistant temperature of the sealed container 60. Therefore, even if the raw material thermoplastic resin pellets 40 at such a temperature are directly stored in the closed container 60, the closed container 60 will not be damaged by heat. In this state, the amount of dissolved oxygen gas per gram of the raw material thermoplastic resin pellet is 0.015 cm ³ or less, and the water content of the raw material thermoplastic resin pellet is 2 × 10 ² ppm or less.

  After the closed container 60 is filled with the raw material thermoplastic resin pellets 40, the inert gas introduction pipe 71 and the inert gas discharge pipe 73 may be connected, or a part of the closed container 60 may be filled with the raw material thermoplastic resin pellets. After filling with 40, the inert gas introduction pipe 71 and the inert gas discharge pipe 73 are connected, and the closed container 60 may be further filled with the raw material thermoplastic resin pellets 40.

Then, an inert gas is introduced into the closed vessel 60 from the inert gas source via the inert gas introduction pipe 71, and the inert gas introduced into the closed vessel 60 is passed through the inert gas discharge pipe 73. Then, the gas is discharged to the inert gas disposal section, and the inside of the sealed container 60 is replaced with the inert gas. The inert gas may be introduced continuously or discontinuously into the closed container 60. In the latter case, the discharge of the inert gas through the inert gas discharge pipe 73 is interrupted when the inert gas is being introduced into the closed container 60. Then, when the inert gas is not introduced into the closed container 60, the vacuum pump is operated to discharge the inert gas through the inert gas discharge pipe 73. Thus, the oxygen gas concentration in the atmosphere inside the sealed container 60 is set to 2% by volume or less (more specifically, 0.1% by volume and 1 × 10 ³ ppm or less). Further, the total amount of moisture in the atmosphere inside the closed container 60 is set to 0.2 mg or less per gram of the raw material thermoplastic resin pellets 40.

  Thereafter, the inert gas introduction pipe 71 and the inert gas discharge pipe 73 of the closed container 60 are closed, and the opening 61 of the closed container 60 is closed with packing. Thereafter, the inert gas introduction pipe 71 and the inert gas discharge pipe 73 are closed using a screw-in cap, and sealing is performed on the joint. Thus, the closed container 60 shown in FIG. 3 was obtained.

  Forty seconds after the start of the replacement with the inert gas inside the closed vessel 60, the oxygen gas concentration in the atmosphere inside the closed vessel 60 became as shown in Table 1.

Thereafter, the raw material thermoplastic resin pellet 1 is kept in a state where the oxygen gas concentration in the atmosphere inside the closed container 60 is set to 2% by volume or less (more specifically, 0.1% by volume or less and 1 × 10 ³ ppm or less). Raw thermoplastic resin pellets having an amount of dissolved oxygen gas per gram of 0.015 cm ³ or less could be stored inside the closed container 60. The same applies to Examples 2 to 20 described later. Further, in Example 1 or Examples 2 to 20 to be described later, the moisture content of the raw material thermoplastic resin pellets was set to 2 × 10 ² ppm or less, and the total moisture in the atmosphere inside the closed container 60 was reduced. The raw material thermoplastic resin pellets could be stored in a state where the amount was 0.2 mg or less per gram of the raw material thermoplastic resin pellets.

  Here, the measured values immediately after storing the raw material thermoplastic resin pellets 40 inside the closed container 60 were as shown in Table 1 below. The measured values after storing the raw material thermoplastic resin pellets in the closed container 60 for 2 weeks were the same as the values shown in Table 1.

  In the following description, the amount of dissolved oxygen gas is defined as follows.

Dissolved oxygen gas amount [A]:
Dissolved oxygen gas amount in raw thermoplastic resin pellets immediately after storage in a closed container Dissolved oxygen gas amount [B]:
The amount of dissolved oxygen gas in the raw thermoplastic resin pellets immediately after the container is stored in a closed container and the sealed container is opened, and the amount of dissolved oxygen gas [C]:
Dissolved oxygen gas amount in raw thermoplastic resin pellets immediately before being used for molding

In the extrusion molding method of the thermoplastic resin in Example 1 or Examples 2 to 10 to be described later, as shown in the conceptual diagram of the extruder in FIG. 3, basically,
(A) a heating cylinder (also referred to as a barrel) 110 having a die 111 for plasticizing and melting raw material thermoplastic resin pellets;
(B) a hopper 120 attached to the heating cylinder 110 to supply the raw material thermoplastic resin pellets to the heating cylinder 110;
It has. And then,
(C) an inert gas source 130, and
(D) a pipe 132 for introducing an inert gas from the inert gas source 130 into the heating cylinder 110;
It has. The driving of the screw 115 is controlled by the screw driving device 118, and the screw 115 is rotated by the screw driving device 118. In addition, the rear end of the heating cylinder 110 connecting the screw driving device 118 and the screw 115 has a sealed structure, for example, a structure in which an inert gas can be introduced into the sealed portion.

  More specifically, this extruder is equipped with a heating cylinder 110 having a die 111 at its tip, a screw 115 built in the heating cylinder 110, and a heating cylinder 110, and a raw thermoplastic resin pellet is placed in the heating cylinder 110. It comprises a hopper 120 for supplying (raw material polycarbonate resin pellets) 40 and a screw driving device 118 attached to the rear end 116 of the screw 115. The screw 115 provided in the heating cylinder 110 plasticizes and melts the resin as described above. A heater (not shown) (not shown) is attached to the outer periphery of the heating cylinder 110, and can plasticize and melt the raw material thermoplastic resin pellets existing in the gap 117 between the heating cylinder 110 and the screw 115. .

  The raw thermoplastic resin pellets 40 are carried into the hopper 120. As a method for carrying the raw material thermoplastic resin pellets from the raw material resin storage unit to the hopper 120, a method of directly dropping by gravity or a pressure feeding method using an inert gas is desirable, but not limited thereto.

  The raw thermoplastic resin pellets 40 carried into the heating cylinder 110 from the hopper 120 are heated, plasticized, melted, and conveyed by the heating cylinder 110 and the screw 115. The screw 115 is rotated by the operation of the screw driving device 118, and the molten thermoplastic resin 41 in the heating cylinder 110 is sent out to the die 111. The molten thermoplastic resin 41 is filled in the space 117 between the screw 115 and the heating cylinder 110 from the portion of the heating cylinder 110 to which the hopper 120 is attached to the die 111, and FIG. Only a part of is shown.

  At the rear end 112 of the heating cylinder 110, which is the part of the heating cylinder 110 on the screw drive side, an airtight member 113 for attaching the rear end 112 to an airtight structure is attached. A seal member 114 for airtightness with the screw 115 is attached to the airtight member 113. Thereby, the airtight state of the portion of the heating cylinder 110 through which the inert gas (for example, nitrogen gas having a purity of about 99.99%) flows can be maintained. When the heating cylinder 110 itself has airtightness, no airtight member or seal member is required. In FIG. 7, the flow of the inert gas is indicated by arrows.

  The extruder further includes a cylinder of 99.999% purity, which is an inert gas source 130, and a pipe 132 for introducing the inert gas from the inert gas source 130 into the heating cylinder 110. . The pipe 132 is attached to a portion of the heating cylinder 110 closer to the screw driving device than the portion of the heating cylinder 110 to which the hopper 120 is attached, more specifically, to the airtight member 113. Note that the pipe 132 may be attached to the rear end 112 of the heating cylinder 110 on the screw driving device side. A pressure control valve 133 and a pressure sensor 134 are provided in the middle of the pipe 132. Further, a second pressure sensor 135 is attached to the hopper 120 to detect the pressure inside the hopper 120. As the pressure control valve 133 and the pressure sensors 134 and 135, those having a well-known system, structure, and configuration can be used. The outputs of the pressure sensors 134 and 135 are sent to a pressure control device 131, and the operations of the pressure control valve 133 and the inert gas source 130 are controlled by the output of the pressure control device 131.

  With such a configuration, the inert gas flows from the inert gas source 130 to the outside of the system via the pipe 132, the heating cylinder 110, and the exhaust part 121 of the hopper 120. That is, the raw material thermoplastic resin pellets 40 are filled in the hopper 120, and the raw material thermoplastic resin pellets are filled in the gap 117 between the heating cylinder 110 and the screw 115 from the portion of the heating cylinder 110 to which the hopper 120 is attached to the die 111. In a state in which the pellets are plasticized, an inert gas flows from the inert gas source 130 to the outside of the system via the pipe 132, the heating cylinder 110, and the hopper 120.

In this state, the pressure of the portion of the heating cylinder through which the inert gas flows (specifically, the rear end portion 112) is, for example, about 2 × 10 ³ Pa (0.02 kgf / cm ² ) higher than the atmospheric pressure. The pressure or pressure change of the inert gas at the rear end portion 112 can be detected by the pressure sensor 134, and based on the detection result of the pressure, the pressure control valve 133 is controlled via the pressure control device 131. The flow rate of the inert gas can be controlled. Further, a change in the pressure in the hopper 120 is detected by the second pressure sensor 135, and the pressure of the inert gas at the rear end portion 112 is detected by the pressure sensor 134. The pressure control valve 133 and the inert gas source 130 can be controlled via 131 to control the flow rate of the inert gas. Thereby, even if the pressure in the hopper 120 changes, the inert gas flowing from the inert gas source 130 to the outside of the system via the pipe 132, the heating cylinder 110, and the hopper 120 can be kept as constant as possible. it can.

  Further, gas generated from the plasticized and molten thermoplastic resin 41 in the gap 117 between the heating cylinder 110 and the screw 115 is discharged from the exhaust part 121 via the hopper 120 together with the inert gas flowing in the heating cylinder 110. It is discharged out of the system.

And in the extrusion molding method of the thermoplastic resin in Example 1 or Examples 2 to 10 described below, the amount of dissolved oxygen gas per gram of the raw material thermoplastic resin pellets is 0.015 cm ³ / gram or less. A certain raw material thermoplastic resin pellet (specifically, a polycarbonate resin pellet) is used as a raw material.

  The raw material thermoplastic resin pellets were stored in the closed container 60 for 2 weeks. Thereafter, the sealed container 60 was opened, and the raw material thermoplastic resin pellets were immediately charged into the hopper 20 provided in the injection molding machine. The same applies to Examples 2 to 10 to be described later. Table 2 shows measured values of the dissolved oxygen gas amount [A], the dissolved oxygen gas amount [B], and the dissolved oxygen gas amount [C].

  In Example 1, the container shown in FIG. 1 made of stainless steel was used as the closed container 60. Thereafter, nitrogen was introduced into the inert gas introduction pipe of the sealed container 60, and then the inert gas discharge pipe was opened. The raw material thermoplastic resin pellets were connected directly to the inside of a hopper (filled with nitrogen in the hopper) provided in the extruder, the pellet outlet and a metal flexible pipe, and immediately charged without contacting oxygen. The same applies to Examples 2 to 6 described later.

In Example 1 or Examples 2 to 7 to be described later, the atmosphere in the hopper 120 into which the raw material thermoplastic resin pellets are charged is set to an oxygen gas concentration of 2 × 10 ³ ppm or less. The first mode was adopted. Specifically, a method of flowing a sufficient amount of nitrogen gas from the inert gas source 130 to the outside of the system via the pipe 132, the heating cylinder 110, and the hopper 120 to discharge oxygen gas in the air in the hopper. , The atmosphere in the hopper 120 was set to an oxygen gas concentration of 2 × 10 ³ ppm or less.

  Then, extrusion molding was performed, and the extruded product finally has a thin rectangular shape cut into a width of 900 mm, a thickness of 2 mm, and a length of 1200 mm. The same applies to Examples 2 to 10 to be described later.

When a C light source was used as the light source of the obtained molded article of Example 1, a 30 cm-thick molded article having a thickness of 30 cm, a 30 cm parallel transmittance at a wavelength of 460 nm, a YI value, a concentration of a residual organic solvent, and a mass of 15 mass% in a methylene chloride solution %, The respective values of the solution YI values of the lysis solution were the same as those shown in Table 2. Here, in the molded article in Example 1, the parallel transmittance was 65% or more, the YI value was 18 or less, the concentration of the residual organic solvent was 4 × 10 ² ppm or less, and 15% by mass was dissolved in a methylene chloride solution. The solution YI value of the solution at this time satisfies 2.1 or less.

Comparative Example 1
Polycarbonate resin pellets synthesized and produced in the same manner as in Example 1 were packed in a paper bag and left at room temperature for one month. Thereafter, the polycarbonate resin pellets were immediately put into a hopper provided in an extruder. The measured value of the dissolved oxygen gas amount [C] at that time was the same value as shown in Table 2. The atmosphere in the hopper was an air atmosphere. The 30 cm parallel transmittance, the YI value, the concentration of the remaining organic solvent, and the solution YI value of the molded product of Comparative Example 1 obtained under the same molding conditions as in Example 1 were the same as those shown in Table 2. there were.

In Example 1, the raw material thermoplastic resin pellets are stored and transported in a closed container having an atmosphere satisfying a predetermined condition, and this atmosphere is maintained until the raw material thermoplastic resin pellets are used. Therefore, for example, the raw material thermoplastic resin pellets in which the amount of dissolved oxygen gas per gram of the raw material thermoplastic resin pellets is 0.015 cm ³ or less can be used as a raw material. A molded article made of a polycarbonate resin having a very small amount of yellow (amber) coloring and negligible and having extremely high transparency, for example, a molded article having an extremely high transparency comparable to a molded article made of a PMMA resin. I got it.

Example 2
The second embodiment is a modification of the first embodiment. In Example 2, the pressure inside the closed vessel 60 was set to 1.3 × 10 ⁴ Pa or less. Immediately after the production of the raw material thermoplastic resin pellets (raw material polycarbonate resin pellets), the raw material thermoplastic resin pellets are housed inside the closed container 60, and the inside of the closed container 60 is evacuated by using a vacuum pump, whereby the closed container 60 is produced. This kind of atmosphere inside was obtained.

The same raw material thermoplastic resin pellets as in Example 1 were stored in the closed container 60 as in Example 1, and stored for the same time as in Example 1. Thereafter, nitrogen was introduced into the inert gas introduction pipe of the sealed container 60, and then the inert gas discharge pipe was opened. The raw material thermoplastic resin pellets were connected directly to the inside of a hopper (filled with nitrogen in the hopper) provided in the extruder, the pellet outlet and a metal flexible pipe, and immediately charged without contacting oxygen. The dissolved oxygen gas amount [C] was not more than 0.015 cm ³ / gram. The molded article had a parallel transmittance of 65% or more, a YI value of 18 or less, a residual organic solvent concentration of 4 × 10 ² ppm or less, and a solution YI value of 2.1 or less.

Example 3
The third embodiment is a modification of the first embodiment. In Example 3, an oxygen gas absorbent was included inside the closed container 60. Then, as in Example 1, the oxygen gas concentration inside the closed container 60 was set to 1 × 10 ³ ppm or less.
The same raw material thermoplastic resin pellets as in Example 1 were stored in the closed container 60 in substantially the same manner as in Example 1, and stored for the same time as in Example 1. Nitrogen was introduced into the inert gas introduction pipe of the sealed container 60, and then the inert gas discharge pipe was opened. The raw material thermoplastic resin pellets were connected directly to the inside of a hopper (filled with nitrogen in the hopper) provided in the extruder, the pellet outlet and a metal flexible pipe, and immediately charged without contacting oxygen. The dissolved oxygen gas amount [C] was not more than 0.015 cm ³ / gram. The molded article had a parallel transmittance of 65% or more, a YI value of 18 or less, a residual organic solvent concentration of 4 × 10 ² ppm or less, and a solution YI value of 2.1 or less.

Example 4
Example 4 is also a modification of Example 1 and employs the second embodiment of the extruder. That is, the pressure in the hopper into which the raw material thermoplastic resin pellets were charged was set to 1.3 × 10 ⁴ Pa or less. In order to set the pressure in the hopper into which the raw material thermoplastic resin pellets are charged to such a pressure, the inside of the hopper may be evacuated using a vacuum pump. Except for this point, the extrusion molding method of the thermoplastic resin of Example 18 can be the same as the extrusion molding method of the thermoplastic resin of Example 1, and thus the detailed description is omitted.

The same raw material thermoplastic resin pellets as in Example 1 were stored in the closed container 60 as in Example 1, and stored for the same time as in Example 1. Thereafter, nitrogen was introduced into the inert gas introduction pipe of the sealed container 60, and then the inert gas discharge pipe was opened. The raw material thermoplastic resin pellets were connected directly to the inside of a hopper (filled with nitrogen in the hopper) provided in the extruder, the pellet outlet and a metal flexible pipe, and immediately charged without contacting oxygen. The dissolved oxygen gas amount [C] was not more than 0.015 cm ³ / gram. The molded article had a parallel transmittance of 65% or more, a YI value of 18 or less, a residual organic solvent concentration of 4 × 10 ² ppm or less, and a solution YI value of 2.1 or less.

  The second embodiment of the extruder described in the fourth embodiment, the third embodiment of the extruder described in a fifth embodiment described later, and the second embodiment of the extruder described in the sixth embodiment It goes without saying that the first to third embodiments can be applied to the fourth embodiment.

Example 5
Example 5 is also a modification of Example 1 and employs a third form of the extruder. That is, in the fifth embodiment, as shown in the conceptual diagram of the extruder in FIG. 4, an exhaust port (vent) 119 is provided in the heating cylinder. The extruder in Example 5 or Example 6 described later has basically the same configuration and structure as the extruder shown in FIG. However, the difference is that the exhaust port (vent) 119 is provided in the compression zone.

In Example 5, the atmosphere in the heating cylinder when plasticizing and melting the raw material thermoplastic resin pellets is set to an oxygen gas concentration of 2 × 10 ³ ppm or less. In order to make the inside of the heating cylinder have such an atmosphere, the pressure may be reduced and discharged by a vacuum pump through an exhaust port (vent) 119, or nitrogen gas may be introduced while reducing the pressure by a vacuum pump. What is necessary is just to replace with sufficient nitrogen gas. Except for this point, the extrusion molding method of the thermoplastic resin of the fifth embodiment can be the same as the extrusion molding method of the thermoplastic resin of the first embodiment, and thus the detailed description is omitted.

The same raw material thermoplastic resin pellets as in Example 1 were stored in the closed container 60 as in Example 1, and stored for the same time as in Example 1. Thereafter, nitrogen was introduced into the inert gas introduction pipe of the sealed container 60, and then the inert gas discharge pipe was opened. The raw material thermoplastic resin pellets were connected directly to the inside of a hopper (filled with nitrogen in the hopper) provided in the extruder, the pellet outlet and a metal flexible pipe, and immediately charged without contacting oxygen. The dissolved oxygen gas amount [C] was not more than 0.015 cm ³ / gram. The molded article had a parallel transmittance of 65% or more, a YI value of 18 or less, a residual organic solvent concentration of 4 × 10 ² ppm or less, and a solution YI value of 2.1 or less.

Example 6
Example 6 is also a modification of Example 1 and employs a fourth form of the extruder. That is, in the sixth embodiment, similarly to the fifth embodiment, the heating cylinder is provided with the exhaust port (vent) 119. The pressure in the heating cylinder at the time of plasticizing and melting the raw material thermoplastic resin pellets is set to 1.3 × 10 ⁴ Pa or less. In order to make the inside of the heating cylinder have such an atmosphere, the pressure may be reduced by a vacuum pump through the exhaust port (vent) 119. Except for this point, the extrusion molding method of the thermoplastic resin of the sixth embodiment can be the same as the extrusion molding method of the thermoplastic resin of the first embodiment, and thus the detailed description is omitted.

The same raw material thermoplastic resin pellets as in Example 1 were packed in a closed container 60 as in Example 1, and stored for the same time as in Example 1. Thereafter, nitrogen was introduced into the inert gas introduction pipe of the sealed container 60, and then the inert gas discharge pipe was opened. The raw material thermoplastic resin pellets were connected directly to the inside of a hopper (filled with nitrogen in the hopper) provided in the extruder, the pellet outlet and a metal flexible pipe, and immediately charged without contacting oxygen. The dissolved oxygen gas amount [C] was not more than 0.015 cm ³ / gram. The molded article had a parallel transmittance of 65% or more, a YI value of 18 or less, a residual organic solvent concentration of 4 × 10 ² ppm or less, and a solution YI value of 2.1 or less.

  Although the present invention has been described based on the preferred embodiments, the present invention is not limited to these embodiments. The structure of the container for storing and transporting the granular material described in the examples, the extruder, the extrusion molding method, the shape of the molded product, the material used, the molding conditions, and the like are merely examples, and can be appropriately changed.

  In the embodiment, in the production of pellets made of polycarbonate resin, the thermoplastic resin was pelletized based on a cold cut method using a strand cutter under an air atmosphere, and then the raw material thermoplastic resin was added to a tank in an inert gas atmosphere. The resin pellet was stored. Then, the raw material thermoplastic resin pellets were placed in the closed container under an air atmosphere, and then an inert gas was introduced into the closed container. However, the present invention is not limited to such a method, and the following method may be adopted. That is, immediately after pelletization, the atmosphere in which the raw material thermoplastic resin pellets are placed may be an inert gas atmosphere (specifically, for example, a nitrogen gas atmosphere). Specifically, after the thermoplastic resin is pelletized based on a cold cut method using a strand cutter, the raw thermoplastic resin pellets are transported and stored in an inert gas atmosphere tank in an inert gas atmosphere tank. Alternatively, the raw material thermoplastic resin pellets may be conveyed under an inert gas atmosphere, and the raw material thermoplastic resin pellets may be placed inside the sealed container under the inert gas atmosphere, and then the opening of the sealed container may be closed.

111: die, 112: rear end of heating cylinder, 113: airtight member, 114: sealing member, 115: screw, 116: rear end of screw, 117 ··· Air gap, 118 ··· screw drive device, 119 ··· exhaust port (vent), 120 ··· hopper, 121 ··· exhaust section, 130 ··· inert gas source, 131 ··· pressure Control device, 132: piping, 133: pressure control valve, 134: pressure sensor, 135: second pressure sensor, 40: raw material thermoplastic resin pellets, 41: heat of fusion Plastic resin, 60 ... closed container, 61 ... opening of closed container, 62 ... bottom of closed container, 71 ... inert gas introduction pipe, 73 ... inert gas discharge pipe, 80 ... Temporary closing device, 81 ... Presser Wood, 82 ... contact portion, 83 ... support member

Claims (12)

A sealed container,
And opening a charging port of the granules on the top of the closed container,
Withdrawal pipe of the granular material at the lower part of the closed container,
An inert gas introduction pipe provided in the extraction pipe,
And an inert gas discharge pipe provided on the pressing member of said opening,
A mechanism and a device for sealing the inert gas introduction pipe,
A storage and transport container for a granular material, comprising a mechanism and a device for sealing the inert gas discharge pipe, wherein the sealed container is filled with a granular material and transported with the inert gas injected.   The method according to claim 1, wherein, when filling the inside of the closed container with the opening portion in an open state, the particulate matter is filled while introducing an inert gas through the inert gas introduction pipe. 2. The container for storing and transporting particulate matter according to claim 1.   The opening is closed, and then an inert gas is introduced into the closed container through the inert gas inlet tube, and the inert gas introduced into the closed container is passed through the inert gas discharge tube. Exhaust gas, thereby replacing the inside of the closed container with an inert gas, thereafter closing the inert gas introduction pipe and the inert gas discharge pipe from the closed container, and closing the opening of the closed container. 3. The container for storing and transporting particulate matter according to claim 2, wherein the container is sealed. The sealed container having an oxygen permeability of 100 cm ³ / (m ² · 24 h · atm) or less and a water vapor permeability at 40 ° C. and 90% RH of 0.1 g / (m ² · 24 hours) or less is used. Then, the inside of the closed container is temporarily filled with a granular material having a dissolved oxygen gas amount of 0.015 cm ³ or less per gram of the granular material, and the opening is temporarily closed, and oxygen in the atmosphere inside the closed container is The container for storing and transporting particulate matter according to claim 1, wherein the opening of the closed container is closed with a gas concentration of 2% by volume or less. With the inside of the closed container filled with a granular material having a water content of 2 × 10 ² ppm or less, the opening was temporarily closed, and the total water content of the atmosphere inside the closed container was calculated per 1 gram of the granular material. The container for storing and transporting particulate matter according to claim 1, wherein the opening of the closed container is closed in a state of 0.2 mg or less.   The container for storing and transporting particulate matter according to claim 1, wherein an oxygen gas absorbent is enclosed inside the closed container. The container for storing and transporting particulate matter according to any one of claims 1 to 6, wherein the pressure inside the closed container is set to 1.3 × 10 ⁴ Pa or less.   The granular material storage and transport container according to any one of claims 1 to 6, wherein the closed container is a metal container made of a SUS-based metal.   7. The container for storing and transporting granular materials according to claim 1, wherein the granular materials are made of polycarbonate resin.   A method for producing a polycarbonate resin sheet or film produced by a melt extrusion molding method using raw materials transported by the container for storing and transporting particulate matter according to claim 9. The molding is performed by inserting an inert gas into a raw material supply hopper installed immediately above the extruder and controlling the oxygen concentration in the hopper to 2.0 × 10 ³ ppm or less. A method for producing a sheet or film produced by the above method.   12. The container for storing and transporting particulate matter is opened while inserting an inert gas into the container for storing and transporting particulate matter according to claim 9 when supplying the raw material to the hopper. 3. The method for producing a sheet or film according to item 1.

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