JPH07224155A - Method for drying thermoplastic norbornene-based resin - Google Patents

Abstract

PURPOSE:To obtain subject resin improved in defective phenomenon such as discoloration of moldings, occurrence of silver streak or surface peeling of moldings and useful as a molding for optics such as lens by retaining a thermoplastic norbornene-based resin under specific conditions and then, heat-drying the resin. CONSTITUTION:When a thermoplastic norbornene-based resin is dried by heating, the resin is retained for >=1hr under atmosphere of <=20mm Hg oxygen partial pressure and then, heat drying is carried out. Furthermore, preferably, heat drying is carried out under atmosphere of <=20mm Hg oxygen partial pressure at >=80 deg.C for 0.1-100hr. The drying is preferably further carried out under atmosphere of an inert gas such as nitrogen or argon or under atmosphere in reduced pressure.

Description

Detailed Description of the Invention

FIELD OF THE INVENTION The present invention relates to a method for drying a thermoplastic norbornene resin. More specifically, when molding is performed, the defective phenomena such as coloring of the molded product, occurrence of silver streak (silver), and peeling of the surface of the molded product due to adhesion of resin to the molding die are improved, resulting in good results. The present invention relates to a method for drying a thermoplastic norbornene-based resin capable of stably molding a molded product having a unique appearance and transparency for a long time.

[0002]

2. Description of the Related Art Thermoplastic norbornene resins have been widely proposed as optical materials because of their excellent transparency, low birefringence and heat resistance. (For example, JP-A-60-168
No. 708, No. 62-252406, No. 62-252407, and No. 60-26024.
Japanese Patent Application, Japanese Patent Application No. 2-133413, Japanese Patent Application Laid-Open No. 63-
145324, JP-A-63-264626, JP-A-1-240517, and JP-B-57-88.
No. 15, etc.). However, since these resins have a large amount of tertiary carbon in the polymer structure, they are easily deteriorated, and because of their high heat resistance, they have a high melting temperature and require high-temperature molding conditions during the molding process. It is likely to cause coloring, and further, to cause defective phenomena such as occurrence of silver streak and surface peeling due to adhesion of resin to the molding die. These are major problems for resin molded products and the like, which are fatal defects particularly in the case of molded products, optical disks, lenses, etc., where transparency is important. With respect to these problems, the inventors previously proposed performing the molding under an inert gas. (JP-A-4-70318)

[0003]

The above proposal was very effective in preventing the coloring of the thermoplastic norbornene-based resin at the time of molding. However, even if the molding is carried out according to the above proposal, the molded product is sometimes colored. In some cases, a defective phenomenon such as the occurrence of a silver strike, the occurrence of a silver strike, or the surface peeling due to the adhesion of the resin to the molding die may occur.

[0004]

Therefore, as a result of intensive investigations, the inventors of the present invention have found that prior to molding a thermoplastic norbornene-based resin, the resin is held under a specific inert gas condition and then dried by heating. As a result, they have found that it is possible to perform molding with good reproducibility and without coloring, and completed the present invention. That is, the present invention is characterized in that, in drying a thermoplastic norbornene-based resin, the thermoplastic norbornene-based resin is characterized by holding for 1 hour or more in an atmosphere having an oxygen partial pressure of 20 mmHg or less before heating and drying, and then heating and drying. The drying method is also a method for drying a thermoplastic norbornene-based resin, characterized by drying at a temperature of 80 ° C. or higher for 0.1 to 100 hours in an atmosphere with an oxygen partial pressure of 20 mmHg or less. 1 in an atmosphere with a pressure of 20 mmHg or less
The present invention provides a method for drying a thermoplastic norbornene-based resin, which is characterized by heating and drying for 0.1 to 100 hours at a temperature of 80 ° C. or higher in an atmosphere having an oxygen partial pressure of 20 mmHg or lower after holding for at least hours. The present invention will be described in detail below.

A first method of the present invention is a method of heating and drying a thermoplastic norbornene-based resin, in which it is held for 1 hour or more in an atmosphere having an oxygen partial pressure of 20 mmHg or less before heating and drying, and then heating and drying. When the atmosphere for holding the thermoplastic resin before heating and drying has an oxygen partial pressure of 20 mmHg or more, coloring by molding cannot be completely prevented unless the heating and drying atmosphere is under an inert gas atmosphere. As an atmosphere having an oxygen partial pressure of 20 mmHg or less, an atmosphere of an inert gas such as nitrogen, argon, helium, carbon dioxide, or a diluted air atmosphere diluted with the inert gas so that the oxygen partial pressure is 20 mmHg or less is used. It can be illustrated. An atmosphere in which the oxygen partial pressure is reduced to 20 mmHg or less by depressurization is also effective. Furthermore, it is effective to combine these methods, and for example, an atmosphere in which diluted air diluted with an inert gas is decompressed and the oxygen partial pressure is set to 20 mmHg can be used. The lower the oxygen partial pressure is, the more preferable. The more preferable range is the oxygen partial pressure of 10 mmHg or less, and more preferably 5 mmHg or less. Oxygen partial pressure 20m
The temperature when placed in an atmosphere of mHg or less is 80 ° C. or less, more preferably 50 ° C. or less, and particularly preferably 35 ° C. or less. When the temperature is high, it is impossible to completely prevent coloring during molding. Also, the time for keeping the oxygen partial pressure below 20 mmHg is 1
It is at least 2 hours, more preferably at least 2 hours.
There is no problem even if the oxygen partial pressure is 20 mmHg or less for a long time. For example, after the pellet production, when packaging the resin, a bag or container with a small oxygen permeation amount is used, and the oxygen partial pressure is 20 mmHg or less. Under the atmosphere of
It is also included in the present invention that the inside of the package is stored for a long period of time while keeping the oxygen partial pressure at 20 mmHg or less and dried as it is. In addition,
Before the resin is heated and dried, the resin is placed in an atmosphere having an oxygen partial pressure of 20 mmHg or less and then dried.
If the period from placing in an atmosphere of mmHg or less to heat drying is relatively short, for example, several hours to about 3 days, it may be in an air atmosphere, but preferably an oxygen partial pressure of 20 mm.
After being placed in an atmosphere of Hg or less, it is immediately heated and dried. Further, the first method of the present invention also includes a method in which the temperature is slowly raised in an atmosphere having an oxygen partial pressure of 20 mmHg or less during heating and drying, and it takes 1 hour or more to reach the temperature of 80 ° C.

In the second method of the present invention, a thermoplastic norbornene resin is used in an atmosphere having an oxygen partial pressure of 20 mmHg or less.
It is a method of heating and drying at a temperature of not less than 0 ° C, preferably 100 ° C or more for 0.1 to 100 hours. Oxygen partial pressure during heating and drying 20m
The atmosphere of mHg or less may be any method of the atmosphere of oxygen partial pressure of 20 mmHg or less which is treated before the first heating and drying of the present invention. Here, heat drying means placing the resin in an atmosphere having a temperature of 80 ° C. or higher, and does not necessarily aim to remove water in the resin. This heat drying temperature is 100
It is more preferable to carry out at a temperature of ℃ or more. The dryer is not particularly limited as long as it has a temperature of 80 ° C. or higher, and a hot air circulation type shelf dryer, a hopper dryer, a shelf vacuum dryer, or an agitator that is usually used for drying resin pellets. Type vacuum dryer can be used. Furthermore, a third method of the present invention is a method in which the first method and the second method are combined, and after the thermoplastic norbornene-based resin is placed in an atmosphere having an oxygen partial pressure of 20 mmHg or less before heating and drying, Heating and drying is also a method performed in an atmosphere having an oxygen partial pressure of 20 mmHg or less. Therefore, as an atmosphere having an oxygen partial pressure of 20 mmHg or less during heating and drying, an atmosphere of an inert gas such as nitrogen, argon, helium, or carbon dioxide, or an inert gas diluted to have an oxygen partial pressure of 20 mmHg or less is used. The diluted air atmosphere described above can be exemplified. An atmosphere in which the oxygen partial pressure is reduced to 20 mmHg or less by depressurization is also effective. Furthermore, it is effective to combine these methods, and for example, an atmosphere in which diluted air diluted with an inert gas is decompressed and the oxygen partial pressure is set to 20 mmHg can be used. The lower the oxygen partial pressure is, the more preferable. The more preferable range is the oxygen partial pressure of 10 mmHg or less, and more preferably 5 mmHg or less.

The norbornene-based thermoplastic resin in the present invention is a monomer comprising at least one norbornene derivative represented by the following general formula (I) (hereinafter referred to as "specific monomer 1").
Or a ring-opening (co) polymer obtained by ring-opening copolymerization of this monomer and a copolymerizable monomer copolymerizable therewith (hereinafter, referred to as a specific ring-opening polymer) A) and a hydrogenated (co) polymer obtained by hydrogenating this specific ring-opened polymer (hereinafter sometimes referred to as a specific hydrogenated polymer), and at least 1 represented by the following general formula (I): Addition copolymer of a monomer composed of one norbornene derivative and one or more α-olefins (hereinafter referred to as a specific α-olefin).
Olefin / norbornene-based copolymer)) is a norbornene-based resin.

[0009]

[Chemical 1]

[Wherein A and B are a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, X and Y are a hydrogen atom, a halogen atom or a monovalent organic group, and l,
m and n are 0 or 1. ]

In the present invention, the specific ring-opening polymer is
For example, JP-A-1-132626 and JP-A-2-10
Examples thereof include ring-opening (co) polymers of compounds having a norbornene ring described in JP-A No. 2221. Further, specific hydrogenated polymers include JP-A-1-132626 and JP-A-2-102221. The polymer obtained by hydrogenating the ring-opening (co) polymer of the compound having a norbornene ring described in 1) can be mentioned. These polymers are obtained by the metathesis ring-opening polymerization of the specific monomer 1, and in the specific monomer 1, X or Y in the general formula (I) is represented by the formula-
The specific monomer which is a group represented by (CH ₂ ) _s COOR or — (CH ₂ ) _s OCOR is preferable in that the resulting polymer is a polymer having a high glass transition temperature and low hygroscopicity. . In particular, this formula - (CH _{2) s} COOR or - (CH _2)
The group represented by _s OCOR is 1 per molecule in the specific monomer.
It is preferable that the individual polymer is contained in that the hygroscopicity of the obtained polymer is lowered, and that the specific monomer in which n is 1 exhibits high heat resistance. In producing the specific ring-opening polymer, two or more types of the specific monomer 1 may be used to prepare a copolymer.

Examples of the compound capable of ring-opening copolymerization with the compound represented by the general formula (I) include cyclopentene, cyclohexene, cycloheptene, cyclooctene, pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] -11-Pentadecene and the like. When using the above ring-opening copolymerizable monomer to obtain a copolymer with the specific monomer represented by the general formula (I), if the amount of the compound represented by the general formula (I) is small, Since the obtained resin cannot have high heat resistance, the proportion of the monomer of general formula (I) is 50 mol% or more, preferably 70% or more, more preferably 80%.
It is necessary to be above.

Metathesis polymerization catalysts used for ring-opening polymerization include ruthenium, rhodium, palladium, iridium,
It is performed using a platinum group compound such as platinum. Also, (a) at least one compound selected from compounds of W, Mo and Re, and (b) periodic table IA, IIA, I
The catalyst may be a compound of at least one element selected from the group consisting of compounds of group IB, IIIB, IVA, or IVB having at least one element-carbon bond or element-hydrogen bond. In this case, the additive (c) which enhances the catalytic activity may be added.
As typical examples of the component (c), alcohols, aldehydes, ketones, amines and the like can be preferably used, however, the compounds shown in Japanese Patent Application No. 63-65817 can also be used.

Further, ring-opening polymerization is carried out by polybutadiene, polyisoprene, styrene-butadiene copolymer, ethylene-
It is also possible to polymerize in the presence of an unsaturated hydrocarbon polymer containing a carbon-carbon double bond in the main chain of propylene-non-conjugated diene copolymer, polynorbornene, etc. In this case, the impact resistance of the resin is generally improves. Among these unsaturated hydrocarbon-based polymers, butadiene-styrene copolymers and isoprene-styrene copolymers are preferred because a resin having good transparency can be easily obtained by changing the ratio of the diene and styrene. In this case, the copolymer of diene and styrene may be a random copolymer or a block copolymer. Upon polymerization in the presence of an unsaturated hydrocarbon polymer, the polymer is 1% to 90%, preferably 3% to 70%, based on the compound represented by the general formula (I).
More preferably 5% to 40% is used.

The specific ring-opening polymer used in the present invention has a molecular weight of ηinh in the range of 0.2 to 5.0, preferably 0.25 to 2.0, more preferably 0.3 to 1. It is 5. The weight average molecular weight (Mw) measured by GPC
And the number average molecular weight (Mn) (Mw / Mn) is 5 or less, preferably 4.5 or less, and particularly preferably 2.0 to 4.0. The specific hydrogenated polymer is produced by subjecting the specific ring-opening polymer obtained by the metathesis ring-opening polymerization to a usual liquid phase hydrogenation reaction. As the catalyst used in this hydrogenation reaction, a catalyst used in a general hydrogenation reaction of an olefinic compound can be used.

The specific α-olefin / norbornene copolymer in the present invention is an α-olefin and the above-mentioned specific monomer 1
Among these, an addition copolymer with a polymer having no polar group (hereinafter referred to as the specific monomer 2), in which the specific monomer 1
Of these, the case where X or Y in the above general formula (I) is hydrogen or a lower alkyl group is preferable because polymerization is easy.
Specific examples of the α-olefin include ethylene, propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene. , 1-octadecene, 1-eicosene, and the like, and α-olefins having 2 to 20 carbon atoms can be exemplified. It is preferable that at least one of the α-olefins is ethylene because a high molecular weight polymer can be easily obtained.

The α-olefin / norbornene copolymer, which is an addition copolymer of the specific monomer 2 and the α-olefin as described above, contains the α-olefin and the specific monomer 1 as essential components. However, in addition to the two essential components, cyclic olefins other than the specific monomer 1 can be polymerized, if necessary, within a range that does not impair the object of the present invention. Examples of such a cyclic olefin include cyclobutene, cyclopentene, cyclohexene,
3,4-dimethylcyclohexene, 3-methylcyclohexene, 2- (2-methylbutyl) -1-cyclohexene, 3a, 5,6,7a
-Tetrahydro-4,7-methano-1H-indene and the like can be mentioned. Such other cyclic olefins alone,
Alternatively, they can be used in combination, and are usually used in an amount in the range of 0 to 50 mol% of the specific monomer 2.

The specific α-olefin / norbornene-based copolymer is obtained by dissolving α-olefin and the specific monomer 2 in a hydrocarbon medium in a hydrocarbon medium by the method described in, for example, JP-A-60-168708. It can be produced by polymerization with a vanadium compound and a halogen-containing compound. The cyclic olefin-based copolymer as described above has α
-The repeating unit derived from the olefin is present in the range of 20 to 90 mol%, preferably 40 to 85 mol%, and the repeating unit derived from the cyclic olefin is 1
It exists in the range of 0 to 80 mol%, preferably 15 to 60 mol%, and the repeating unit derived from α-olefin and the repeating unit derived from the specific monomer 2 are randomly arranged substantially linearly. is doing. The α-olefin composition and the specific monomer composition were measured by ₁₃ C-NMR. The fact that this specific α-olefin / norbornene-based copolymer is substantially linear and does not have a gel-like crosslinked structure was confirmed by the complete dissolution of the copolymer in 135 ° C decalin. it can.

The intrinsic viscosity [η] of such a specific α-olefin / norbornene-based copolymer measured in decalin at 135 ° C. is 0.10 dl / g or more, preferably 0.15 to 2 as described above. 0.0 dl / g, particularly preferably 0.15 to 1.5 dl / g. Also, GPC
The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) measured by 5 is 5 or less, preferably 4.5 or less, and particularly preferably 2.0 to 4.0.

The crystallinity of this α-olefin / norbornene-based copolymer measured by the X-ray diffraction method is
0 to 10%, preferably 0 to 7%, particularly preferably 0
Is in the range of up to 5%. Such cyclic olefin copolymers are disclosed in JP-A-60-168708 and JP-A-61.
-120816, Japanese Patent Application Laid-Open No. 61-115912, Japanese Patent Application Laid-Open No. 61-115916, Japanese Patent Application No. 61-9
5905, Japanese Patent Application No. 61-95906, Japanese Patent Application Laid-Open No. 61-271308, Japanese Patent Application Laid-Open No. 61-27221.
It can be produced by appropriately selecting the conditions according to the method described in Japanese Patent No. 6 or the like.

More specifically, for example, in a cyclohexane medium using a continuous polymerization apparatus, the specific monomer 1
As tetracyclo [4.4.0.1 _2,5.17,10 ] -3
-Dodecene (hereinafter sometimes abbreviated as TCD-3) is α
-Ethylene is used as olefin and VO is used as catalyst
(OCH ₂ CH ₃ ) Cl ₂ / Al (CH ₂ CH ₃ ) _1.5 Cl _1.
5 , using a reaction temperature of 10 ° C. and a reaction time (polymerization residence time)
It can be produced by employing the condition that the copolymerization reaction of ethylene and TCD-3 is carried out in 30 minutes. As a method for separating and recovering the specific ring-opening polymer, the specific hydride, and the specific α-olefin / norbornene-based copolymer from the reaction solution, the method usually used for recovering the polymer from the polymer solution may be used as it is. , For example, a steam coagulation method of directly contacting the polymer solution with steam, a method of precipitating the polymer by adding a poor solvent to the polymer (hereinafter referred to as a poor solvent precipitation method), heating the polymer solution in a container, It can be appropriately adopted depending on the properties of the polymer and the solvent, such as the method of distilling off the solvent and the method of pelletizing while removing the solvent with a vented extruder. Among them, the steam coagulation method and the poor solvent precipitation method perform heat drying in order to remove water and the solvent used for precipitation. In any case, the resin pellets are produced at a high temperature, but it is preferable that the operation is performed at 50 ° C. or higher, particularly 100 ° C. or higher, in an atmosphere free of oxygen.
In packaging, it is preferable that the thermoplastic norbornene-based resin is packaged and stored under nitrogen, or packaged and stored under reduced pressure to reduce oxygen in the packaging bag and the storage container.
Alternatively, the filling may be performed in a normal atmosphere, and then the inside of the packaging bag or the storage container may be purged with nitrogen to reduce the pressure to nitrogen, or the pressure may be reduced. Coexistence of an oxygen absorber in the packaging bag or storage container is also effective.

The thermoplastic norbornene-based resin which is the object of the present invention is a plain resin of the specific ring-opening polymer, the specific hydrogenated polymer, the specific α-olefin / norbornene-based copolymer and the resins as described above. In addition to the mixture, a thermoplastic norbornene-based resin composition obtained by blending these thermoplastic norbornene-based resins with another thermoplastic resin or a rubber-like elastic material is also targeted. The thermoplastic resin that can be used to produce the thermoplastic norbornene-based resin composition is a polymer having a glass transition temperature of 25 ° C. or higher, and is an amorphous polymer, a crystalline polymer, a liquid crystal polymer. Etc. are included. Specific examples of the thermoplastic resin include styrene resin, vinyl chloride resin, acrylic resin, polyphenylene ether resin, polyarylene sulfide resin, polycarbonate resin, polyester resin, polyamide resin, polyether sulfone resin, polysulfone. Resin, polyimide resin and the like. The weight ratio of the blended thermoplastic norbornene resin to other thermoplastic resin is 1
0-95: 90-5, preferably 15-90: 85-1
The ratio is 0, more preferably 20 to 80:80 to 20. Further, a resin composition obtained by blending such a thermoplastic norbornene-based resin and another thermoplastic resin contains a rubber-like polymer and a rubber-reinforced thermoplastic resin, either alone or in combination of both. It may be. Here, the rubber-like polymer is a polymer having a glass transition temperature of 0 ° C. or lower, and includes a usual rubber-like polymer and a thermoplastic elastomer.

The rubber-like elastic material that can be used for producing the thermoplastic norbornene-based resin composition is a polymer having a glass transition temperature of 0 ° C. or lower, which is a usual rubber-like polymer and a thermoplastic elastomer. Is included. The weight ratio of the blended thermoplastic norbornene-based resin to the rubber-like elastic material is 10 to 95:90 to 5, preferably 15 to 90:85 to 10, and more preferably 20 to 80 :.
The ratio is 80 to 20. Further, the thermoplastic norbornene-based resin of the present invention, and the thermoplastic norbornene-based resin composition containing the same, heat resistance stabilizer, weather resistance stabilizer, antistatic agent, slip agent, antiblocking agent, antifog agent, lubricant, dye, Pigments, natural oils, synthetic oils, waxes and the like can be added, and the mixing ratio is an appropriate amount. For example, as a stabilizer to be added as an optional component, specifically, a phenol-based antioxidant, a sulfur-based antioxidant, and a phosphorus-based antioxidant can be used.

Examples of the phenolic antioxidant used here include 2,6-di-tert-butyl-p-cresol and stearyl-β- (4-hydroxy-3,5-di-tert-butylphenol. ) Propionate, 4,4'-butylidene bis (6-tert-
Butyl-m-cresol), 1,3,5-tris (3,5, -di-tert-butyl-4-hydroxybenzyl) -2,4,6-trimethylbenzene, tetrakis [methylene-3- (3,3 5-Di-tert-butyl-4-hydroxyphenylpropionate] methane, 2-octylthio-4,6-di (4-hydroxy-3,5-di-tert-butyl) phenoxy-1,3,5-triazine Can be mentioned.

Examples of sulfur type antioxidants include dilauryl thiopropionate, distearyl thiopropionate, pentaerythritol tetralauryl thiopropionate and the like. Examples of phosphorus antioxidants include trioctyl phosphite, trilauryl phosphite, tridecyl phosphite,
Octyl-diphenylphosphite, tris (2,4, -di-
tert-Butylphenyl) phosphite, triphenyl phosphite, tris (3,5-di-tert-butyl-4-hydroxyphenyl phosphite, tris (mono / di mixed nonylphenyl) phosphite, bis (2,4- Di-tert-butylphenyl) pentaerythritol diphosphite,
Examples thereof include bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol phosphite.

The phenol antioxidant, sulfur antioxidant and phosphorus antioxidant are 0 to 10 parts by weight, preferably 0 to 5 parts by weight, based on 100 parts by weight of the thermoplastic norbornene resin. Is used in an amount of 0 to 3 parts by weight. Also, as lubricants and mold release agents, zinc stearate, calcium stearate, fatty acid metal salts such as calcium 12-hydroxystearate, glycerin monostearate, glycerin monolaurate, glycerin distearate, pentaerythritol monostearate, pentaerythritol diester. Examples thereof include fatty acid esters of polyhydric alcohols such as stearate and pentaerythritol tristearate, and alkali salts of aliphatic sulfonic acids. These may be blended alone or in combination.

In the present invention, the thermoplastic norbornene-based resin may be silica, diatomaceous earth, alumina, titanium oxide, magnesium oxide, pumice powder, pumice stone balloon, aluminum hydroxide, water to the extent that the object of the present invention is not impaired. Magnesium oxide, basic magnesium carbonate, dolomite, calcium sulfate, potassium titanate, barium sulfate, calcium sulfite, talc, clay, mica, asbestos, glass fiber, glass flakes, glass beads,
Calcium silicate, montmorillonite, bentonite,
Fillers such as graphite, aluminum powder, molybdenum sulfide, boron fibers, silicon carbide fibers, polyethylene fibers, polypropylene fibers, polyester fibers and polyamide fibers may be blended.

The thermoplastic norbornene-based resin which has been subjected to the treatment of the present invention can be molded into a molded product by a known molding method such as injection molding, compression molding or extrusion molding. The molding can be performed in an air atmosphere, but it is preferable to use the method disclosed in Japanese Patent Laid-Open No.
The method according to 70318 is preferred. In addition, a hard coat layer made of an inorganic compound, an organic silicon compound such as a silane coupling agent, an acrylic resin, a vinyl resin, a melamine resin, an epoxy resin, a fluorine resin, a silicone resin, etc. on the surface of the formed molded product. Can be formed. Examples of the means for forming the hard coat layer include known methods such as a thermosetting method, an ultraviolet curing method, a vacuum vapor deposition method, a sputtering method, and an ion plating method. , Chemical resistance, abrasion resistance and moisture permeability can be improved.

[0029]

EXAMPLES Examples of the present invention will be described below.
The present invention is not limited to these. still,
In the following Examples and Comparative Examples, unless otherwise specified, parts mean parts by weight and% means% by weight. The evaluation method was as follows.

Injection molding: injection molding machine (Niigata Iron Works NN3
0B) a 80 × 55 × 2.4 mm molded plate was produced.
In the molding, molding was performed while flowing nitrogen gas into the hopper of the molding machine. Total light transmittance: According to ASTM D1003. Yellowness index (YI): measured using a color difference meter color analyzer.

[0031] Reference Example 1 specific monomer as a 8-methyl-8-carboxymethyl tetracyclo [4.4.0.1 ^2,5 .1 ^17,10] -3- dodecene 176 kg, and xylene 704Kg, molecular weight 13 kg of 1-hexene, which is a regulator, was charged into a reaction vessel in which nitrogen gas was replaced, and WCl6 which was a ring-opening polymerization catalyst was added to the reaction vessel.
Dimethoxyethane solution (concentration 0.05 mol / l) 3
1, xylene solution of paraaldehyde (concentration 0.1 mol / l) 1.5 l, and n-hexane solution of diethyl aluminum chloride (concentration 0.8 mol / l) 3.7 l were added, and the mixture was mixed at 80 ° C. for 3 hours. Time metathesis ring-opening polymerization reaction,
A polymer mixture was obtained. The polymerization conversion rate in this metathesis ring-opening polymerization reaction was 96%. Put 900kg of the resulting polymer solution by the above method to the high-pressure reactor, a hydrogenation catalyst RuHCl (CO) [P (C ₆ H _{5) 3] 3} 7
5g was added, hydrogen gas pressure was 100kg / cm2, reaction temperature was 1
The mixture was stirred at 65 ° C for 8 hours. After cooling the obtained reaction liquid, hydrogen gas was released to obtain a hydrogenated polymer solution. The hydrogenation rate was almost 100%. The obtained hydrogenated polymer solution was placed in a decatalytic reaction vessel, 1.2 kg of lactic acid and 1.7 kg of methanol were added, and the system was heated and stirred at 60 ° C. for 30 minutes to form a homogeneous phase, and then allowed to reach room temperature. After cooling, 450 kg of methanol was added and the mixture was heated at 80 ° C. for 1 hour. Then, the solution was cooled to room temperature and the polymer containing phase and the polymer non-containing phase were separated. Subsequently, 200 kg of methanol and 250 kg of xylene were added to the polymer-containing phase, and the system was added to 60
After keeping the temperature at 1 ° C. for 1 hour, the temperature was returned to room temperature, and then the polymer-containing phase and the polymer-free phase were separated. IRGANOX1 in the polymer phase
After adding 0.85 kg of 076 (manufactured by Ciba-Geigy), the mixture was transferred to a desolvation container and heated to 280 ° C. to dissolve the polymer solution, and pelletized resin A was obtained by passing through a pelletizer. The obtained pellets had an ηinh of 0.45, and the resin A was once stored in a hopper that had been replaced with nitrogen, and then a portion of the resin was filled and stored in a paper bag under the atmosphere (resin A1). Further, a part of the resin was filled and stored in a closed stainless steel container in which nitrogen was replaced from the hopper under nitrogen (resin A2).

Reference Example 2 7-ethylidenetetracyclo [4.
4.0.1 ^2,5 . A ring-opening polymerization reaction was carried out in the same manner as in Reference Example 1 except that 140 kg of 1 ^7,10 ] -3-dodecene was used and the solvent was changed to 560 kg of toluene to obtain a polymer mixed solution. Using this polymer mixture, RuHCl as a catalyst
A hydrogenation reaction was carried out in the same manner as in Reference Example 1 except that 10 kg of a palladium catalyst supported on silica magnesia (Pd supporting rate 5%) was used instead of (CO) [P (C ₆ H ₅ ) ₃ ] _3. A hydrogenated polymer mixed solution was obtained by filtration, and after filtering, the catalyst was detouched and desolvated in the same manner as in Reference Example 1 to obtain a pellet-shaped resin B. Hydrogenation rate is almost 100%, ηinh is 0.44
Resin B was once stored in a hopper that had been purged with nitrogen, and then filled and stored in a paper bag under the atmosphere (Resin B).
1).

Reference Example 3 Using a polymerization vessel having a volume of 1 liter equipped with a stirring bath, a copolymerization reaction of ethylene and tetracyclododecene was continuously carried out. That is, a cyclohexane solution of tetracyclododecene was added from the top of the polymerization vessel at 0.4 l / hr so that the concentration of tetracyclododecene in the polymerization vessel was 60 g / l, and VO (OC ₂ H ₅ ) Cl ₂ was added as a catalyst. 0.5 l / hour of the cyclohexane solution so that the vanadium concentration in the polymerization vessel was 0.5 mmol / l (the vanadium concentration supplied at this time was about 2.9 times the concentration in the polymerization vessel), isobutyl sesquichloride _{(Al (i-C 4 H} 9) 1.5
Per hour 0 as the aluminum concentration of the cyclohexane solution in the polymerization vessel was 4.0 mmol / l of Cl _{1 .5).}
4 liters and cyclohexane were continuously fed into the polymerization reactor at a rate of 0.7 liters per hour, while the polymerization solution in the polymerization reactor was constantly 1 liter from the upper portion of the polymerization reactor (that is, the residence time was 0.5 It was taken out continuously (in time). A bubbling tube was used for the polymerization system to add ethylene at 20 l / h, nitrogen at 10 l / h, and hydrogen at 0.5 l / h.
Was fed at the rate of. The copolymerization reaction was carried out at 10 ° C. by circulating a refrigerant through the jacket of the polymerization vessel. A cyclohexane / isopropyl alcohol (1/1) mixed liquid was added to the polymerization liquid extracted from the upper part of the polymerization vessel to stop the polymerization reaction. Then, the catalyst and solvent were removed in the same manner as in Reference Example 1 to obtain pellet-shaped resin C.
Got Ηinh of the obtained pellets is 0.45,
The resin C was once stored in a hopper that had been purged with nitrogen, and then filled and stored in a paper bag under the atmosphere (resin C1).

Example 1 Two pellets (resin A1) of a thermoplastic norbornene-based resin produced in Reference Example 1 and stored in a warehouse for 30 days after production were used.
After being placed in a nitrogen atmosphere at 5 ° C. for 50 hours, it was dried by heating with hot air at 120 ° C. for 15 hours in an air atmosphere. The obtained pellet was injection-molded to obtain a molded plate. The total light transmittance and YI value of the molded plate are shown in Table 1. Example 2 The resin A1 stored in the warehouse for 30 days after the production was placed in a reduced pressure atmosphere of 5 mmHg at 25 ° C. for 5 hours, and then dried by vacuum heating at 120 ° C. for 15 hours in the same reduced pressure atmosphere. The obtained pellets were injection-molded in the same manner as in Example 1, and the total light transmittance and YI value of the obtained molded plate were measured and shown in Table 1.

Example 3 In Example 1, the nitrogen atmosphere was changed to an oxygen partial pressure of 10 m.
Example 1 except that mHg and nitrogen partial pressure of 750 mmHg were used.
The same treatment as above was carried out, and the total light transmittance and the YI value of the obtained molded plate were measured and shown in Table 1. Example 4 An experiment was carried out in the same manner as in Example 2 except that the treatment of placing in a reduced pressure atmosphere of 5 mmHg at 25 ° C. for 5 hours was not performed. Total light transmittance and Y of molded plate obtained by injection molding
The I value is shown in Table 1.

Comparative Example 1 In Example 1, hot air drying was carried out at 120 ° C. for 15 hours without treatment under a nitrogen atmosphere at 25 ° C. for 50 hours,
The total light transmittance and YI value of the molded plate obtained by injection molding were measured and are shown in Table 1. Example 5 Resin A2 produced in Reference Example 1 as the resin and stored for 30 days after the production was used, and hot-air drying was performed at 120 ° C. for 15 hours without treatment under a nitrogen atmosphere at 25 ° C. for 50 hours. The same experiment as in Example 1 was performed. When the atmosphere in the stainless steel container was examined before heating and drying, the oxygen content was 0.1% or less. The total light transmittance and YI value of the molded plate obtained by injection molding were measured and are shown in Table 1.

Example 6 The same process as in Example 2 was carried out except that the resin was produced in the reference example and the resin B1 was stored in the warehouse for 30 days after production. The total light transmittance and YI value of the molded plate obtained by injection molding were measured and are shown in Table 1. Example 7 An experiment similar to that of Example 6 was performed except that the treatment at 25 ° C. for 5 hours under vacuum was not performed before the heat drying. The total light transmittance and YI value of the molded plate obtained by injection molding were measured and are shown in Table 1. Comparative Example 2 Using resin B1 stored in a warehouse for 30 days after manufacture, hot air drying was performed at 120 ° C. for 15 hours without performing treatment before heat drying,
The total light transmittance and YI value of the molded plate obtained by injection molding were measured and are shown in Table 1. Example 8 The same process as in Example 2 was carried out except that the resin was produced in Reference Example 3 and the resin C1 was stored in the warehouse for 30 days after production. The total light transmittance and YI value of the molded plate obtained by injection molding were measured and are shown in Table 1. Example 9 An experiment similar to that of Example 6 was performed except that the treatment at 25 ° C. in vacuum for 5 hours was not performed before the heat drying. The total light transmittance and YI value of the molded plate obtained by injection molding were measured and are shown in Table 1. Comparative Example 3 Using resin C1 stored in a warehouse for 30 days after production, hot air drying was performed at 120 ° C. for 15 hours without performing the treatment before heating and drying.
The total light transmittance and YI value of the molded plate obtained by injection molding were measured and are shown in Table 1.

[0038]

[Table 1]

[0039]

EFFECTS OF THE INVENTION When a thermoplastic resin having a norbornene skeleton in a repeating unit which is subjected to the drying method of the present invention is molded, the molded product is colored, silver streaks are generated, and the molding surface is caused by the adhesion of the resin to a mold. Defects such as peeling are greatly reduced. Therefore, the molded product of the thermoplastic resin having the norbornene skeleton in the repeating unit obtained by the molding method of the present invention is, for example, an optical molded product such as a lens, an optical disk, an optical fiber, an optical waveguide, a plastic mirror, or an automobile head. It is used for automobile molded products such as lamp covers and tail lamp covers, resin plates for window glasses, molded products for building materials such as roofing agents such as carports, and housing molded products for electrical products.

Claims (2)

[Claims] 1. When heating and drying a thermoplastic norbornene-based resin, the thermoplastic norbornene-based resin is characterized by holding for 1 hour or more in an atmosphere with an oxygen partial pressure of 20 mmHg or less before heating and drying, and then heating and drying. How to dry. 2. A thermoplastic norbornene-based resin at a temperature of 80.degree.
A method for drying a thermoplastic norbornene-based resin, which comprises heating and drying for 1 to 100 hours. [0001]