JPH11166039A - Drying of thermoplastic norbornene-based polymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a molded article of a thermoplastic norbornene-based polymer having excellent heat-resistance, water resistance, strength, etc., and free from minute defects such as micro-voids by drying a thermoplastic norbornen- based polymer at a high temperature before molding. SOLUTION: The thermoplastic norbornene-based polymer (A) is dried at a high temperature before molding. The component A is e.g. a polymer having a structural unit of formula I (R1 and R2 are each H, a hydrocarbon residue, a halogen or a polar group such as pyridyl; R1 and R2 may together form a ring; (n) is a positive integer; (q) is 0 or a positive integer) and/or the formula II (R3 and R4 are same as R1 and R2 ; (l) and (m) are each same as (n); (p) is same as (q)). The component A is preferably pelletized and preparatorily dried before molding. The pelletized component A preferably contains an antioxidant. The drying is carried out preferably at a high temperature lower than the glass transition temperature (Tg) of the component A, more preferably between (Tg-30) and (Tg-5).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for drying a thermoplastic norbornene-based polymer, and more particularly to a method for drying a thermoplastic norbornene-based polymer under high-temperature conditions before molding. By drying the thermoplastic norbornene-based polymer before molding, a molded article without microvoids can be obtained. Therefore, according to the drying method of the present invention, it is possible to obtain a molded article having excellent heat resistance, water resistance, strength, and the like, and having no fine defects such as microvoids.

[0002]

2. Description of the Related Art Generally, polyolefin-based polymers are
Because it has a structure consisting of only carbon and hydrogen and no unsaturated bond, it has low affinity for water, does not absorb or transmit moisture,
Further, it has a feature of high resistance to acids, alkalis, other chemicals and various solvents. Typical examples are polyethylene and polypropylene, which are formed into sheets, films, cylinders or rods by melt extrusion and used for a wide range of applications. However, these conventional materials have insufficient heat resistance, and have a drawback that they are deformed by heating at a relatively low temperature of 70 to 80 ° C. or lower, and cannot be used at higher temperatures. In addition, these materials had poor transparency and could not be used for optical applications.

On the other hand, polycarbonate (PC) and polymethyl methacrylate (PMMA) have been mainly used as optical transparent plastic molding materials such as optical disc substrates and plastic lenses. However, PC has a large birefringence, and PMMA has a large water absorption and an insufficient heat resistance, which makes it difficult to meet increasingly sophisticated requirements. Recently,
Thermoplastic saturated norbornene polymers such as hydrogenated ring-opening polymers of norbornene monomers and addition polymers of norbornene monomers and ethylene are attracting attention as optical plastic molding materials for optical disc substrates and the like. (JP-A-60-26024, JP-A-64-24826, JP-A-60-168708, JP-A-61-115912, JP-A-61-120816
Issue).

[0004] These thermoplastic saturated norbornene-based polymers are a kind of polyolefin-based polymer, exhibit excellent water resistance, chemical resistance, and solvent resistance like other polyolefins, and have a high glass transition temperature of 100 ° C or higher. It is a highly transparent material that can synthesize a heat-resistant polymer and has a total light transmittance of 90% or more. From the above, the thermoplastic saturated norbornene-based polymer not only can be used for various applications as a polyolefin material having heat resistance, but also has small birefringence and excellent transparency, water resistance, and heat resistance. As a transparent material, it can be applied to optical applications.

However, these thermoplastic saturated norbornene polymers are brittle as compared with polyethylene, polypropylene, and PMMA, and when extruded into sheets, films, or rods, they are easily broken or broken and do not have sufficient strength. In addition, there are also problems that foam-like defects often occur in the extruded product, appear as visually streaks on the surface, and further reduce the strength. In addition, even if there is no visible large streak, when observing in detail using an optical microscope etc.,
Fine voids and crack-like defects (hereinafter, referred to as “microvoids”) that are invisible to the naked eye often occur in the interior. Until now, in the extrusion molding of thermoplastic saturated norbornene-based polymers, a molded product without any microvoids has been used. Had not been obtained.

As another method for obtaining a sheet-like or film-like molded article, there is a casting method in which a polymer is cast as a solution of an appropriate solvent and the solvent is evaporated. According to this method, a molded article having almost no microvoids is obtained. can get. However, even in the case of a molded product having a thickness of about several μm, the solvent does not completely evaporate and remains for about several percent, so that sufficient strength cannot be obtained, or the Each time the residual solvent evaporates, the characteristics of the molded article change, or the evaporated solvent adversely affects other components incorporated around the molded article. A film or sheet-like molded product requires a tensile strength of 800 kg / cm ² or more, preferably 900 kg / cm ² or more from the viewpoint of durability, but a cast material having such a sufficient strength is required. Not obtained. Therefore, conventionally, it is a sheet-shaped or film-shaped molded product made of a thermoplastic saturated norbornene-based polymer, which has no voids or crack-like defects at all, and has a sufficient tensile strength of 800 kg / cm ² or more. What you have is not offered.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a thermoplastic norbornene-based polymer capable of providing a molded article free of microvoids. Another object of the present invention is to provide a thermoplastic norbornene-based polymer which is excellent in heat resistance, water resistance, strength, and the like and can provide a molded article free from defects such as foaming and streaks. The present inventors have studied in detail a molded article using a thermoplastic norbornene-based polymer as a molding material. When observed in detail using a microscope, it was found that fine voids and crack-like defects were easily generated inside.

The present inventors have conducted intensive studies to solve the problem of microvoids. As a result, pellets obtained by melt-extruding a thermoplastic norbornene-based polymer are subjected to high-temperature conditions, such as glass, before extrusion molding. Transition temperature (Tg)
It has been found that a molded article free of microvoids can be obtained by using it after drying under slightly lower temperature conditions. This drying treatment is also effective when injection molding a molding material comprising a thermoplastic norbornene-based polymer. The molded article thus obtained has excellent durability under high temperature and high humidity, and does not generate microvoids for a long period of time.

As the thermoplastic norbornene-based polymer, when a thermoplastic saturated norbornene-based polymer having an appropriate range of molecular weight and molecular weight distribution is molded,
It is preferable because it has sufficient strength. In addition, low volatile components such as an unreacted monomer and a solvent are mixed in the conventional thermoplastic norbornene-based polymer, and it has been found that this is a cause of a decrease in strength due to foaming and a streak on the surface.
0.3% by weight of volatile components contained in these polymers
By performing the following, foaming and generation of large visible striations can be suppressed even in the case of extrusion molding.
It has been found that depending on the type of antioxidant to be added to these thermoplastic saturated norbornene-based polymers, the reduction in strength due to foaming and the generation of surface streaks are promoted. By selecting and using
It has been found that problems such as polymer decomposition, deterioration, and coloring can be solved without impairing those properties. The present invention has been completed based on these findings.

[0010]

Thus, according to the present invention, there is provided a method for drying a thermoplastic norbornene-based polymer, comprising drying the thermoplastic norbornene-based polymer under high-temperature conditions before molding.

According to the present invention, the following embodiments of the present invention are provided. 1. The above drying method, wherein the pelletized thermoplastic norbornene-based polymer is pre-dried before molding. 2. The above drying method, wherein the pelletized thermoplastic norbornene-based polymer contains an antioxidant. 3. The antioxidant has a vapor pressure of 10 ⁻⁶ P at 20 ° C.
a. The drying method as described above, 4. The above drying method, wherein the thermoplastic norbornene-based polymer is dried under a high temperature condition lower than the glass transition temperature (Tg) of the polymer. 5. The above drying method, wherein the drying is performed under a temperature condition of (Tg-30) to (Tg-5) ° C. 6. The above drying method, wherein the drying is performed under a temperature condition of (Tg-20) to (Tg-5) ° C. 7. The above drying method, wherein the drying is performed for one hour or more under a high temperature condition. 8. The above drying method of vacuum drying. 9. The above drying method of drying under an atmosphere of air or nitrogen. 10. The above drying method, wherein the thermoplastic norbornene-based polymer is a thermoplastic saturated norbornene-based polymer. 11. The thermoplastic saturated norbornene-based polymer has a number average molecular weight (Mn) of 50,000 to 500,000 and a weight average molecular weight (Mw) of 100,000 to 2,000,000, as measured by high performance liquid chromatography.
A molecular weight distribution (Mw / Mn) of 2.2 or more; and
The above drying method, wherein the volatile component contained in the polymer is 0.3% by weight or less of the polymer.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. (Thermoplastic norbornene-based polymer) The molding material targeted by the present invention is a thermoplastic norbornene-based polymer, typically a thermoplastic saturated norbornene-based polymer, and specific examples thereof include the following general formula [I] and And / or a polymer having a structural unit represented by [II]. General formula [I]

[0013]

Embedded image Wherein, in the formula, R ₁ and R ₂ are hydrogen, a hydrocarbon residue or a polar group such as halogen, ester, nitrile, and pyridyl, which may be the same or different, and R ₁ and R ₂ are May form a ring with each other. n
Is a positive integer. q is 0 or a positive integer. General formula [II]

[0014]

Embedded image Wherein R ₃ and R ₄ are hydrogen, a hydrocarbon residue or a polar group such as halogen, ester, nitrile, pyridyl, and may be the same or different, and R ₃ and R ₄ are May form a ring with each other. l and m are positive integers. p is 0 or a positive integer. ]

The polymer having the structural unit represented by the general formula [I] includes, as monomers, for example, norbornene and its alkyl- and / or alkylidene-substituted products;
For example, 5-methyl-2-norbornene, 5,6-dimethyl-2-norbornene, 5-ethyl-2-norbornene, 5-butyl-2-norbornene, 5-ethylidene-
2-norbornene and the like; dicyclopentadiene, 2,3-
Dihydrodicyclopentadiene, an alkyl-substituted product thereof such as methyl, ethyl, propyl, and butyl, and a polar-substituted product such as halogen; dimethanooctahydronaphthalene, its alkyl and / or alkylidene-substituted product;
And polar group substituents such as halogen, for example, 6-methyl-1,4: 5,8-dimetano-1,4,4a, 5,6.
7,8,8a-octahydronaphthalene, 6-ethyl-
1,4: 5,8-dimethano-1,4,4a, 5,6
7,8,8a-octahydronaphthalene, 6-ethylidene-1,4: 5,8-dimethano-1,4,4a, 5
6,7,8,8a-octahydronaphthalene, 6-chloro-1,4: 5,8-dimetano-1,4,4a, 5
6,7,8,8a-octahydronaphthalene, 6-cyano-1,4: 5,8-dimethano-1,4,4a, 5
6,7,8,8a-octahydronaphthalene, 6-pyridyl-1,4: 5,8-dimethano-1,4,4a, 5
6,7,8,8a-octahydronaphthalene, 6-methoxycarbonyl-1,4: 5,8-dimethano-1,4,
4a, 5,6,7,8,8a-octahydronaphthalene and the like; cyclopentadiene trimer to tetramer, for example, 4,
9: 5,8-Dimethano-3a, 4,4a, 5,8,8
a, 9,9a-octahydro-1H-benzondene,
4,11: 5,10: 6,9-trimethano-3a, 4,4
4a, 5, 5a, 6, 9, 9a, 10, 10a, 11,
11a-dodecahydro-1H-cyclopentaanthracene or the like is used, and the ring-opened polymer obtained by polymerization by one or more known ring-opening polymerization methods is hydrogenated by an ordinary hydrogenation method. Is a saturated polymer. Hydrogenated ring-opening polymer (saturated polymer)
To make the glass transition temperature (Tg) of 100 ° C. or higher,
Among these norbornene-based monomers, tetracyclic or 5
It is preferable to use a cyclic compound, or to use these as a main component and to use them together with a bicyclic or tricyclic monomer. Especially,
From the viewpoint of birefringence, it is preferable to use a tetracyclic lower alkyl-substituted or alkenyl-substituted compound as a main component.

The polymer having the structural unit represented by the general formula [II] is a polymer obtained by addition-copolymerizing, as a monomer, one or more of the above-mentioned norbornene monomers and ethylene by a known method. And / or hydrogenated products thereof, all of which are saturated polymers. Further, the thermoplastic saturated norbornene-based monomer may be used as a molecular weight modifier in the production process of the polymers [I] and [II] as α- such as 1-butene, 1-pentene and 1-hexene.
-The presence of an olefin or cyclopropene, cyclobutene, cyclopentene, cycloheptene,
It may be a copolymerized polymer by adding other monomer components such as cycloolefin such as cyclooctene and 5,6-dihydrocyclopentadiene as small components.

The thermoplastic saturated norbornene-based polymer of the present invention has a number average molecular weight (Mn) of 50,000 to 500,000, preferably 60, as measured by high performance liquid chromatography using toluene as a solvent and graphy (HLC) analysis. 2,000 to 200,000, the weight average molecular weight (Mw) is 100,000 to 2,000,000, preferably 100,000 to 1,000,000,
It is preferable that the molecular weight distribution (Mw / Mn) is 2.2 or more. When Mn and Mw are smaller than the above ranges,
When a film, sheet, rod, or the like is formed by extrusion, a molded product having sufficient strength cannot be obtained. Conversely, if it is larger than this range, the moldability will be poor, and molding will be difficult even when used for extrusion because of too high viscosity. Further, even if the solution is dissolved in an appropriate solvent and cast or spun, the solubility in the solvent is insufficient. In addition, it is difficult to control the synthesis reaction of such a high molecular weight polymer, and there is a disadvantage that a material having stable quality cannot be obtained.

The molecular weight distribution (Mw / Mn) is 2.
It is preferably at least 2, more preferably at least 2.4, particularly preferably at least 2.8. In general, it is considered that a thermoplastic polymer having a smaller molecular weight distribution and closer to monodispersion has a better balance between strength and moldability and has better performance. However, when a polymer having a relatively large molecular weight is extruded as in the present invention to form, for example, a sheet or a film, in the process of cooling and solidifying from a molten state, monodisperse molecules are instantaneously at a certain temperature. In the case where molecules of various molecular weights are gradually solidified in order from the one having the larger molecular weight than in the case where they are solidified at the same time, a stress-free residual product can be obtained, and a flat and clean molded product as a whole can be obtained. In a thermoplastic saturated norbornene-based polymer,
This tendency is particularly remarkable because the polymer is rigid, has high heat resistance, and has a considerably high molding temperature of around 300 ° C. Therefore, for the purpose of the present invention, the molecular weight distribution is preferably 2.2 or more, more preferably 2.4 or more, and particularly preferably 2.8 or more.
If the molecular weight distribution is smaller than this range, extrusion molding is difficult, and it is difficult to obtain a molded article having good smoothness and optical characteristics.

As the molecular weight distribution (Mw / Mn) increases, the moldability improves. In general, when a polymer having high heat resistance and high rigidity such as polycarbonate is rapidly cooled from a molten state, internal deformation occurs and a phenomenon that a flat molded product cannot be obtained easily occurs. The same applies to thermoplastic norbornene-based polymers. For example, when extruding from a T-die with an extruder and pulling the sheet, a phenomenon occurs in which a flat sheet cannot be pulled unless the temperature of the roll is increased. Tg is 14
In the case of a polymer of about 0 ° C, the roll temperature is set to 120 to 14
By raising the temperature to 0 ° C., the sheet can be pulled flat. However, usually, the heating of the roll is often by water,
In many cases, the temperature of the roll can be raised only up to about 90 ° C.

If the molecular weight distribution is less than 2.2, the molding cannot be performed well even if the temperature of the roll is raised to about 140 ° C., which is close to the glass transition temperature of the polymer. By raising the temperature, a flat molded product can be formed. Further, when the molecular weight distribution spreads to 2.8 or more, the moldability is further improved, and a molded product which is flat and has no internal distortion even at a roll temperature of about 90 to 100 ° C. can be obtained. The upper limit of the molecular weight distribution is not particularly limited, but if it is too large, Mn is large, and sufficient strength cannot be obtained for a high melt viscosity, and the synthesis of such a polymer itself becomes difficult. , Approximately 6.0 or less is preferable.

A thermoplastic saturated norbornene-based polymer having such a molecular weight (Mn, Mw) and a molecular weight distribution (Mw / Mn) can be used in a synthesis reaction, for example, by adjusting the amount of a catalyst used or changing the polymerization temperature. Or, when using a molecular weight regulator, the type and amount can be adjusted, and further,
The monomer can be added to the reaction system with a prop later, or a monomer having a small molecular weight and a monomer having a large molecular weight can be separately synthesized, and these can be blended to broaden the molecular weight distribution. In the case where unsaturated bonds remaining in the molecular chain of the synthesized polymer are saturated by a hydrogenation reaction, the hydrogenation rate is 90% or more, preferably 95% or more, particularly from the viewpoint of light resistance and weather resistance. Preferably, it is 99% or more. From the viewpoints of heat resistance and moldability, the polymer of the present invention has a Tg of 100 ° C. or higher, preferably 120 to 200 ° C., more preferably 1 to 200 ° C.
It is desirable that the temperature be 30 to 180 ° C.

(Method of Reducing Volatile Components) A thermoplastic saturated norbornene-based polymer generally contains 0.5% by weight or more of a volatile component in a usual synthesis method. The molding material of the present invention has a volatile component contained in the thermoplastic saturated norbornene-based polymer of 0.3% by weight or less, preferably 0.2% by weight or less, more preferably 0.1% by weight or less. Desirably. In the present invention, a differential thermogravimeter (TG / DTA2 manufactured by Seiko Instruments Inc.)
Using (00), the loss on heating from 30 ° C. to 350 ° C. is determined, and that amount is defined as the content of the volatile component. When the content of the volatile component is more than the above range, when the extrusion molding is performed at a temperature of about 250 to 350 ° C., the volatile component volatilizes during the molding and foams to cause a defect inside the molded product or to decrease the strength. Or appear as streaks on the surface.

As a method for reducing volatile components, for example, in a polymer coagulation method using a poor solvent, there is a method of repeatedly performing coagulation. Direct drying method, 250 ° C or higher, 30To
It is desirable to dry at rr or less using a thin film dryer or an extrusion dryer. Alternatively, the solvent solution of the polymer can be directly dried after being concentrated to several tens% in advance. Of course, it is not limited to these methods. The thermoplastic saturated norbornene-based polymer produced by these methods is substantially amorphous, is excellent in transparency, dimensional stability, heat resistance, water absorption, and hardly recognizes moisture permeability.

(Antioxidant) In the present invention, if a low volatility antioxidant is blended in a proportion of 0.01 to 5 parts by weight with respect to 100 parts by weight of the thermoplastic saturated norbornene-based polymer, Can effectively prevent decomposition and coloring of the polymer. As the antioxidant, 2
An antioxidant having a vapor pressure at 0 ° C. of 10 ⁻⁵ Pa or less, particularly preferably 10 ⁻⁸ Pa or less, is desirable. Vapor pressure of 10
Antioxidants higher than ^-5 Pa cause problems such as foaming during extrusion molding, and volatilization of the antioxidants from the surface of molded articles when exposed to high temperatures. Examples of the antioxidant that can be used in the present invention include the following, and one or more of these may be used in combination.

Hindered finol 2,6-di-tert-butyl-4-methylphenol,
6-di-t-butylphenol, 4-hydroxymethyl-2,6-di-t-butylphenol, 2,6-di-t
-Butyl-α-methoxy-p-dimethyl-phenol,
2,4-di-t-amylphenol, t-butyl-m-
Cresol, 4-t-butylphenol, styrenated phenol, 3-t-butyl-4-hydroxyanisole, 2,4-dimethyl-6-t-butylphenol, octadecyl-3- (3,5-di-t-butyl- 4-hydroxyphenyl) propionate, 3,5-di-t-butyl-4-hydroxybenzylphosphonate-diethyl ester, 4,4'-bisphenol, 4,4'-
Bis- (2,6-di-t-butylphenol), 2,
2'-methylene-bis- (4-methyl-6-t-butylfinol), 2,2'-methylene-bis- (4-methyl-6-α-methylcyclohexylphenol),
4,4'-methylene-bis- (2-methyl-6-t-butylphenol), 4,4'-methylene-bis- (2,
6-di-t-butylphenol), 1,1'-methylene-bis- (2,6-di-t-butylnaphthol), 4,
4'-butylidene-bis- (2,6-di-t-butyl-
Meta-cresol), 2,2'-thio-bis- (4-methyl-6-t-butylphenol), di-o-cresol sulfide, 2,2'-thio-bis- (2-methyl-
6-t-butylphenol), 4,4'-thio-bis (3-methyl-6-t-butylphenol), 4,4 '
-Thio-bis- (2,3-di-sec-amylphenol), 1,1'-thio-bis- (2-naphthol),
3,5-di-t-butyl-4-hydroxybenzyl ether, 1,6-hexanediol-bis- [3- (3
5-di-t-butyl-4-hydroxyphenyl) propionate], 2,4-bis- (n-octylthio) -6
-(4-hydroxy-3,5-di-tert-butylanilino) -1,3,5-triazine, 2,2-thio-diethylenebis [3- (3,5-di-tert-butyl-4-hydroxy) Phenyl) propionate], 2,2-thiobis (4-methyl-6-t-butylphenol), N, N '
-Hexamethylenebis (3,5-di-t-butyl-4-
Hydroxy-hydrocinnamamide), calcium bis (3,5-di-t-butyl-4-hydroxybenzylphosphonate) calcium, 1,3,5-trimethyl-2,4,6
-Tris- (3,5-di-t-butyl-4-hydroxybenzyl) benzene, triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], 1, 3,5-trimethyl-2,4,6, -tris (3,5-di-t-butyl-4
-Hydroxybenzyl) benzene, tris- (3,5-
Di-tert-butyl-4-hydroxybenzyl) -isocyanurate, pentaerythrityl-tetrakis [3-
(3,5-di-t-butyl-4-hydroxygenyl)
Propionate] and the like.

Aminophenols normal butyl-p-aminophenol, normal butyroyl-p-aminophenol, normal peragonoyl-p-aminophenol, normal lauroyl-p-aminophenol, normal stearoyl-p-aminophenol, , 6-di-t-butyl-α-dimethyl, amino-p-cresol and the like. Hydroquinone-based hydroquinone, 2,5-di-t-butylhydroquinone, 2,5-di-t-amylhydroquinone, hydroquinone methyl ether, hydroquinone monobenzyl ether and the like.

Phosphite triphosphite, tris (3,4-di-t-butylphenyl) phosphite, tris (nonylphenyl) phosphite, tetrakis (2,4-di-t-butylphenyl) -4,4 '-Biphenylenephosphanite, 2
-Ethylhexyl octyl phosphite and the like. In addition, 2-mercaptobenzothiazole zinc salt, dicatechol borate-di-o-tolylguanidine salt, nickel-dimethyldithiocarbamate, nickel-pentamethylene dithiocarbanate, mercaptobenzimidazole, 2-mercaptobenzimidazole zinc salt and the like.

(Other Components) The thermoplastic saturated norbornene-based polymer of the present invention may contain, as an additive other than an antioxidant, various antistatic agents, lubricants, and surfactants as long as the object of the present invention is not impaired. And an ultraviolet absorber may be added for use. Further, when used for applications other than optical materials, if necessary, additives such as fillers such as glass fibers, dyes, and pigments may be added.

(Pelletizing and Pre-Drying) The plastic material is usually about 1 to 7 mm in diameter and 4 to 8 mm in length.
The pellets are supplied in the form of pellets, and are formed into a desired shape by extrusion molding or injection molding. By the way, generally, the polymer after synthesis removes the solvent used at the time of synthesis by a coagulation method or a direct drying method, and adds the necessary amount of the above-mentioned various additives to this, and in the case of a thermoplastic saturated norbornene-based polymer, In a molten state at a temperature of about 230 ° C. or more, the mixture is extruded into a strand having a predetermined diameter, and then cut into a desired length by a suitable strand cutter to form a pellet. In the case of ordinary plastic materials, this pellet is formed as it is.For example, polycarbonate resin, acrylic resin, polyamide resin and other highly hygroscopic or easily decomposable resins absorb moisture during storage of the pellet, By molding as it is,
Since foaming is severe and defects such as large streaks occur on the surface of the molded product, it is common practice to pre-dry for several hours below the glass transition temperature of the resin before using it and then mold it. I have.

However, since the thermoplastic norbornene-based polymer has low hygroscopicity and does not contain a component which decomposes during storage, it is conventionally considered that this pre-drying is unnecessary, and the thermoplastic norbornene-based polymer is formed without pre-drying. Was. Actually, even if pre-drying is attempted, almost no volatile components are detected.
However, surprisingly, when the pellets of the thermoplastic norbornene-based polymer were pre-dried, fine voids and crack-like defects that could not be seen visually without pre-drying occurred in the molded article, whereas these It has been found that a microvoid-free molded article can be obtained. The molded article obtained in this manner has no microvoids even after molding, and has microvoids even after a durability test at a high temperature and high humidity of 70 ° C. or more and a relative humidity of 80% or more and 20 hours or more, for example. Does not occur. It was also confirmed that this drying treatment was effective for injection molding.

As conditions for the pre-drying, it is effective that the temperature is high and the drying time is long. However, if the temperature is higher than the glass transition temperature of the resin, the pellets are thermally fused to each other, making it difficult to use. And (Tg-30) to (Tg-5) ° C.
It is particularly preferable to perform the treatment at (Tg-20) to (Tg-5) ° C., preferably for 1 hour or more, particularly preferably for 2 hours or more. Drying is effective whether it is vacuum drying or normal pressure drying in an air or nitrogen atmosphere. The time from the end of the drying treatment to the time of use for molding is not short, but does not need to be particularly short, and the effect is not lost even after several days.

(Molding Method) The thermoplastic norbornene-based polymer obtained by the drying method of the present invention is particularly suitable for extrusion molding, but is not limited thereto. In extrusion molding, using a melt extruder, a thermoplastic norbornene-based polymer is heated to about 250 to 300 ° C., extruded from a T-type or manifold-type die, and wound up with various rolls to form a sheet or film. be able to. In this case, since the thermoplastic norbornene-based polymer has high heat resistance and high rigidity, if it is rapidly cooled by a roll, the surface is wavy like a polycarbonate and cannot be formed flat, so that the first-stage and second-stage windings are performed. As described above, it is appropriate to set the cooling roll to a relatively high temperature of about 70 to 140 ° C. in accordance with the value of the molecular weight distribution (Mw / Mn) to remove the cooling. Further, the sheet-like molded product can be further stretched uniaxially or biaxially to be processed.

In addition, in order to further enhance the strength and gas permeability by processing with a calender roll, other olefin resins such as polyethylene and polypropylene, polyester resins such as polyethylene terephthalate, polyvinyl chloride and polyvinylidene chloride, and the like. Coextrusion or lamination with a halogenated hydrocarbon resin or the like is also possible. Also, by extruding from an appropriate die, it can be extruded into a rod shape, a fiber shape, or a tube shape. These extruded products can be stretched at a temperature equal to or lower than the glass transition temperature and processed into a thinner rod or tube. Further, in order to increase the strength, crosslinking can be performed by heating or irradiation with radiation such as ultraviolet rays or electron beams. In this case, it is effective to use an appropriate crosslinking agent. Known crosslinking agents can be used, for example, monomers having a plurality of vinyl groups such as divinylbenzene; polyfunctional acrylates such as diallyl phthalate, ethylene glycol dimethacrylate, and trimethylolpropane trimethacrylate; triallyl isocyanurate and the like Isocyanurates; and polymers having a plurality of unsaturated bonds such as liquid polybutadiene.

The thermoplastic norbornene-based polymer of the present invention can be formed by the following molding method in addition to melt extrusion molding. It can be formed into a sheet by hot pressing. Further, a thermoplastic norbornene-based polymer is dissolved in an aromatic hydrocarbon-based solvent such as benzene, toluene, and xylene; an alicyclic hydrocarbon-based solvent such as cyclohexane, methylcyclohexane and decalin; and a halogen-based solvent such as chloroform and monochlorobenzene. These solutions can be cast on a flat plate or on a roll to form a film. For a polymer having a relatively large molecular weight, it can be spun from the solvent solution. A polymer having a relatively small molecular weight can be subjected to ordinary injection molding, and a general thermoplastic resin processing method such as rotational molding can be applied.

(Optical material and conductive composite material) The thermoplastic norbornene-based polymer of the present invention (molding material)
Is suitable for various optical materials, particularly as a substrate material for optical recording media, because it is amorphous, has excellent transparency and low birefringence. The molded article obtained from the thermoplastic norbornene-based polymer of the present invention, on its surface, by a thin film forming method such as vacuum evaporation or sputtering, metal, metal oxide, metal nitride, metal sulfide,
A metal halide or the like can be formed into a single layer or a multilayer depending on the purpose. At this time, the molded product obtained by the present invention may be exposed to a considerably high temperature in a vacuum, but the molded product obtained by the present invention has a small amount of volatile components and a small amount of outgas. In addition, a flat film free from occurrence of “swelling” or the like can be formed on the surface.

A recording medium can be manufactured by providing an optically recordable and / or readable recording thin film on a transparent substrate. As a recording material for forming a recording thin film (recording layer), any known rare earth-transition metallurgy amorphous alloy may be used. For example, a Tb-Fe-based alloy (Japanese Patent Publication No.
No. 20691), a Dy-Fe alloy (JP-B-57-20)
No. 692), Cd-Tb-Fe-based alloys (JP-A-56-1)
No. 26907), Cd-Tb-Dy-Fe-based alloys (JP-A-57-94948), and Cd-Co-based alloys (JP-A-5-94948).
No. 4-121719) and Tb-Fe-Co type. These rare earth-transition metal amorphous layers are preferably formed by a thin film forming method such as vapor deposition, sputtering, or ion plating. The thickness of this amorphous layer is generally between 500 and 1500 degrees. Further, a phase-change type recording material may be used as the recording layer.
e system, Sb-Te system, In-Sb system, Ge-Sb-Te
System, In-Sb-Te system and the like. These phase-change recording materials are preferably formed by a method such as vapor deposition, sputtering, or ion plating. The thickness of this amorphous layer is generally between 500 and 2000 °.

Organic dye-based recording materials can also be used, for example, methine / polymethine-based materials (dianines: indolonine type, thiazole type, etc., croconiums, squaryliums) (JP-A-58-113696); quinones; Naphthoquinones and anthraquinones (Japanese Unexamined Patent Publication No.
199291, JP-A-58-112793); phthalocyanines (metal phthalocyanines) (JP-A-61-112793)
235188, JP-A-59-11292); dithiol-based (dithiol metal complexes) (JP-A-57-1109)
No. 0); other, tetrahydrocholines, dioxane,
Dithiazines, thiapyryliums, porphyrins (JP-A-58-1970088, JP-A-61-235188)
And JP-A-59-78891). The film thickness of this organic dye-based recording material after film formation is generally 500 to 5000 °.

Further, for example, Te-CS ₂ , Pb-Te
_{-Se, Te-C, TeO 2} , Sb-Se, Bl-Te
Etc., or a write-once type recording card using a shape change such as bubble formation. Further, gold, platinum, aluminum or the like can be used as the reflection film. In the optical recording medium, a surface protective layer may be provided on the surface, or a protective layer, a reflective layer, and a dielectric layer may be provided between the recording layer and the substrate made of the polymer of the present invention. Examples of layer forming materials such as these protective layers include CdS, ZnSe, SiO ₂ , Si, and Si.
_{3 N, Si 3 N 4,} AlN, TiO 2, TaO 2, TaO 2,
An inorganic substance such as MgF ₂ or an organic substance such as an ultraviolet curable resin can be used. Further, in the case of an optical card or the like, other materials may be directly bonded and used. In this case, in addition to a normal adhesive such as a solvent, a hot melt, a UV-curable adhesive, a high-frequency wave, an ultrasonic wave, or the like. An adhesive method is used.

(Uses) The thermoplastic norbornene-based polymer of the present invention is a plastic optical fiber for short-distance information transmission including automobile and medical use and its connectors; a lens for picking up information, and a lens for a projector. , Eyeglass lenses, sports goggles,
Plastic lenses such as lenses and covers for head lamps and tail lamps of automobiles and the like; transparent electrodes for displaying information such as touch electrodes and liquid crystal substrates provided with a transparent conductive film on the surface, screens, polarizing films, and anti-glare filters for CRTs Making use of moisture resistance and insulation properties, insulating films of electronic devices, etc., moisture resistant coatings; medical tools such as syringes, pipettes, chemical containers, containers and films for optical analysis; windshields for automobiles, windshields for motorcycles, aircraft Window materials, windows for housing, transparent shutters, window materials and mirrors such as lighting equipment; beverage containers such as juices, alcoholic beverages, and carbonated beverages; food containers; packaging films, solvents with the addition of appropriate fillers, dyes, pigments, etc. It is useful for applications such as moisture-resistant paints. In addition, composite materials having a conductive film formed on the surface include a transparent film that can be used for touch electrodes and liquid crystal substrates, as well as materials for electronic devices such as high-frequency circuit boards and films for capacitors. It is also useful. Optical recording media having a recording thin film on the surface include optical cards,
It is useful as a reflective or dye-based information recording medium such as an optical floppy, an optical tape, and various memories for computers.

[0040]

The present invention will be specifically described below with reference to Synthesis Examples and Examples. In the following examples, parts and percentages are by weight unless otherwise specified.

[Synthesis Example 1] (Synthesis of ring-opening polymer) Under a nitrogen atmosphere, 90 parts of dehydrated toluene, 0.5 part of triethylaluminum, 1.4 parts of triethylamine, and 1- 0.08 parts of hexene was added. Ethyl tetracyclododecene (ETD) 30
And 0.17 part of titanium tetrachloride were continuously added to the reaction system over 1 hour to carry out a polymerization reaction. ETD
After adding the total amount of and titanium tetrachloride, the reaction was carried out for 1 hour. Next, the reaction was stopped by adding a mixed solution of isopropyl alcohol / aqueous ammonia (0.5 parts / 0.5 parts), and the reaction product was poured into 500 parts of isopropyl alcohol to coagulate. The coagulated polymer is cured at 60 ° C for 10
After vacuum drying for 2 hours, 25.5 parts of a ring-opened polymer was obtained. (Hydrogenation reaction) The obtained ring-opened polymer was dissolved in 200 parts of cyclohexane, and 0.6 parts of a palladium / carbon catalyst (supporting amount: 5%) was added into a 200-liter autoclave, and hydrogen pressure was 70 kg / cm ² , A hydrogenation reaction was performed at a temperature of 140 ° C. for 4 hours.

(Post-treatment) After removing the hydrogenation catalyst by filtration, the reaction solution was poured into 600 parts of isopropyl alcohol to coagulate. The obtained hydrogenated product is heated at 60 ° C.
For 10 hours, and then redissolved in cyclohexane to obtain a 10% solution. Isopropyl alcohol 60
Pour into 0 parts and coagulate again. Dry as above
After one more solidification, the resulting hydrogenated product was vacuum dried at 90 ° C. for 48 hours to obtain 22.6 parts of a hydrogenated product. The yield was 75%. (Characteristics of Polymer) The hydrogenation rate of the obtained hydrogenated product was 99% or more according to ¹ H-NMR spectrum analysis. In addition, high performance liquid chromatography (HLC) analysis using toluene as a solvent (manufactured by Tosoh Corporation, HLC8
02L, TSKgelG5000H-G4000
As a result of measuring the molecular weight (in terms of polystyrene) at a temperature of 38 ° C. and a flow rate of 1.0 ml / min using H as a column,
Number average molecular weight (Mn) 7.0 × 10 ⁴ , weight average molecular weight (Mw) 17.5 × 10 ⁴ , molecular weight distribution (Mw / Mn)
2.5. The glass transition temperature (T
g) was measured, and the volatile content was determined by thermogravimetric analysis (TGA) from 30 ° C. to 3 ° C. at a rate of 10 ° C./min in a nitrogen atmosphere.
When measured as a loss on heating up to 50 ° C., Tg was 1
At 42 ° C., the volatiles were 0.08%.

(Pelletization) With respect to 100 parts of the obtained thermoplastic norbornene-based polymer, as an antioxidant,
1,3,5-trimethyl-2,4,6-tris (3,5
-Tert-butyl-4-hydroxybenzyl) benzene (trade name Irganox 133, manufactured by Ciba Geigy)
0, and a vapor pressure of 1.3 × 10 ⁻¹² Pa), and after mixing with a Henschel mixer, pellets were formed at 230 ° C. using an extruder. (Molding) Using a 30 mmφ extruder manufactured by Thermoplastics Co., Ltd., the resin temperature was raised to 280 ° C. and heated to melt.
Extruded from mold die, width 20cm, thickness 100μm
Was obtained. At this time, the temperature of the take-up roll is
The temperature was 130 ° C in the first stage and 121 ° C in the second stage. Visual observation revealed that there was no streak on the film surface, no foaming inside, and a transparent and defect-free film was obtained. When the tensile strength was measured, it was 900 kg / cm ² . Further, when this film was observed by rotating it while sandwiching it between two polarizing plates whose polarizing axes were perpendicular to each other, there was no bright portion and no birefringence. Further, the film is placed in an air oven for 110 minutes.
Heating at 48 ° C. for 48 hours showed no coloration.

Example 1 The following experiment was conducted to check the effect of preliminary drying. The pellets obtained in Synthesis Example 1 were directly extruded under the same conditions as in Synthesis Example 1,
A sheet-shaped molded product having a thickness of 500 μm was obtained. The tensile strength of the sheet was 900 kg / cm ² . When this molded product was visually observed, there were no transparent and large defects. However, when the microvoids were counted by observing 10 visual fields with a 400 × optical microscope, microvoids having a size of about 5 μm were observed. In addition, this sheet
After being kept in a thermo-hygrostat at 90 ° C. and a relative humidity of 90% for 1000 hours, it was taken out and visually observed. As a result, a large number of small crack-like defects were observed. Similarly, Table 1 shows the test results for the sheet obtained by subjecting the pellets of Synthesis Example 1 to pre-drying by changing various drying conditions using a hot air dryer and then forming and processing the sheets together with the above results.

[0045]

[Table 1] (Note) The evaluation criteria for microscopic observation are as follows. A: No microvoids, B: Number of microvoids 2 or less, C: Number of microvoids 4 or less, D: Number of microvoids 5 or more.

[0046]

According to the drying method of the present invention, there is provided a thermoplastic norbornene-based polymer capable of providing a molded article free from fine defects such as microvoids. The thermoplastic norbornene-based polymer obtained by the present invention is a molding material excellent in heat resistance, water resistance, strength, etc., and has no defects due to foaming and the like, and in particular, a molded article having no microvoids by drying treatment. Can be given. The thermoplastic norbornene-based polymer obtained by the present invention,
Since it has excellent optical characteristics such as transparency, it is suitable for optical applications and also as a conductive composite material. Using a transparent substrate obtained from the thermoplastic norbornene-based polymer of the present invention, an optical recording medium having excellent durability and the like can be manufactured.

Claims (8)

[Claims] 1. A method for drying a thermoplastic norbornene-based polymer, comprising drying the thermoplastic norbornene-based polymer under high-temperature conditions before molding. 2. The drying method according to claim 1, wherein the pelletized thermoplastic norbornene-based polymer is pre-dried before molding. 3. The pelletized thermoplastic norbornene-based polymer contains an antioxidant.
The drying method described. 4. The drying method according to claim 1, wherein the thermoplastic norbornene-based polymer is dried under a high temperature condition lower than the glass transition temperature (Tg) of the polymer. 5. The drying method according to claim 4, wherein the drying is performed under a temperature condition of (Tg-30) to (Tg-5) ° C. 6. The drying method according to claim 1, wherein the drying is performed in a vacuum. 7. The drying method according to claim 1, wherein the drying is performed in an air or nitrogen atmosphere. 8. The drying method according to claim 1, wherein the thermoplastic norbornene-based polymer is a thermoplastic saturated norbornene-based polymer.