JP2619856B2 - Optical materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention particularly relates to an optical material utilizing transparency and a high refractive index.

[Conventional technology]

Polystyrene, polymethyl methacrylate and polycarbonate have been studied as optical disc substrates, optical fibers or plastic lenses as plastics having high transparency and high refractive index, and some of them have been put to practical use. However, polystyrene has a heat distortion temperature of about 90 ° C. and has poor heat resistance and a large refractive index, and is easily dissolved in ethyl acetate and carbon tetrachloride and has poor solvent resistance. The entry into the field of optical materials has been greatly delayed, and is substantially at a standstill. Polymethyl methacrylate has good molding and excellent transparency,
Since the heat resistance is superior to that of polystyrene, it is the most advanced plastic in the optical material field.
However, there is a problem that a solvent crack is easily generated by acetone, ethyl acetate, and the like, and a large hygroscopic property is liable to be deformed by hygroscopicity. In any case, the heat deformation temperature is about 110 ° C., which limits the practical use range. Although it seems at first glance that polycarbonate has good solvent resistance in terms of being difficult to dissolve, it appears to be good, but in many cases, whitening occurs, and solvent resistance is practically inadequate when used for optical materials. In addition, there is also a problem that it is easily immersed in a strong alkali, has poor chemical resistance, and has insufficient water resistance. Also,
There is also a problem that the birefringence and the shrinkage are larger than those of the former two.

As described above, the above-mentioned various plastics used as raw materials for plastics-based optical materials currently studied or used have respective advantages and disadvantages. The resulting optical materials have advantages but also disadvantages compared to conventional inorganic glass systems. In other words, taking a compact disk (CD) as an example of an optical disk substrate, a car audio CD has a very high temperature inside the car in midsummer, so heat resistance is required. However, polystyrene cannot be used, and there is concern about use of polymethyl methacrylate. Although there is no concern about the heat resistance of polycarbonate, there is a problem that it is difficult to mold a disc substrate having good shrinkage or birefringence after molding.
What has been described above poses a serious problem for use in write-once discs and rewritable discs. In addition, there are problems with each solvent resistance, chemical resistance, and water resistance, and there are restrictions on the place of use and handling method. Such problems also occur in other optical materials such as optical fibers and plastic lenses that utilize transparency.

[Problems to be solved by the invention]

In view of such circumstances, the present inventors have excellent heat resistance, chemical resistance, solvent resistance, and water resistance, and have substantially no shrinkage, dimensional stability, excellent moldability, and substantial birefringence. In order to provide an optical material which is not present in the art, research has been repeated, and the present invention has been reached.

[Means for solving the problem]

That is, the present invention relates to a copolymer comprising (A) an α-olefin component having 2 to 10 carbon atoms and (B) a monomer component represented by the formula (1), wherein the copolymer comprises (B) An optical material characterized in that the monomer component comprises a copolymer having a structure represented by the formula (2).

(Wherein RR ^{1 to} R ¹² are hydrogen, an alkyl group having 1 to 4 carbon atoms or halogen, which may be the same or different, and R ⁹ or R ¹⁰ and R ¹¹ or R ¹² are each other ^May be a ring. N is 0, 1, 2, or 3, and when R ^{5 to} R ⁸ are repeated a plurality of times, they may be the same or different.) Function and Effect] In the copolymer constituting the optical material of the present invention, the monomer component represented by the above formula (1) mainly has a structure represented by the formula (2). Preferred embodiments of such a copolymer include a copolymer comprising α-olefin and / or a cyclic olefin other than formula (1) together with the monomer component of the formula (1), and the copolymer is particularly preferable. Examples of the essential components include those containing a monomer of the formula (1) and ethylene.

In the copolymer, the monomer component of the formula (1) has at least 2
Mol% or more, but when ethylene coexists, the molar ratio of ethylene / the monomer component of the formula (1) is 5 /
The range is preferably from 95 to 95/5, particularly preferably from 40/60 to 90/10. When α-olefins other than ethylene, chain dienes or cyclic olefins other than the formula (1) coexist, the total of these monomers is used. The molar ratio of the amount / the monomer component of the formula (1) is preferably in the range of 5/95 to 95/5, particularly preferably 30/70 to 90/10. In the present invention, the monomer component of the formula (1) is not limited to a single component, and a plurality of components represented by the formula (1) may, of course, be mixed.

Specific examples of the monomer component represented by the formula (1) include the following, but the examples shown here are extremely limited and are represented by the formula (1). Anything can be the monomer component of the present invention.

Among them, those in which n = 1 in equation (1), that is, equation (3), The monomer component represented by is preferred in terms of availability of the monomer or easy synthesis of the monomer.

To produce the above-mentioned monomer component, for example, US Pat. No. 3,557,072 (Japanese Patent Publication No. 46-14910) or
No. 154133 can be applied. For example, to produce the monomer component of the formula (3), cyclopentadiene is condensed with norbornene as shown in the following formula.

The monomer component represented by the formula (1) other than the formula (3) is basically an application of the above condensation reaction, and is only different from the starting material.

The α-olefin that can be copolymerized with the monomer component of the formula (1) includes α-olefin having 2 to 20 carbon atoms, preferably 2 to 10 carbon atoms.
Olefins such as ethylene, propylene, 1-butene, 3-methyl-1-butene, 1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-hexane, 1-octane , 1-decene, 1-
Dodecene, 1-tetradecene, 1-hexadecane, 1-
Ikosen etc. can be illustrated. Of these, ethylene is particularly preferred from the viewpoint of copolymerizability. Even when other α-olefin (having 3 or more carbon atoms) or a cyclic olefin described below is copolymerized with the monomer component of the formula (1), ethylene is preferred. The better the copolymerizability, the better.

Cyclic olefins other than the formula (1), which are other components that can be copolymerized with the monomer component of the formula (1), include non-crosslinked cycloolefins and styrenes such as cyclopentene, cyclohexene, and 3,4-dimethyl. Ciclepentene, 3-methylcyclohexene, 2- (2-methylbutyl) -1-cyclohexene, styrene, α-methylstyrene, 2,3,3a, 7a-tetrahydro-4,7-methano-
Examples thereof include 1H-indene and 3a, 5,6,7a-tetrahydro-4,7-methano-1H-indene. Polyenes such as dicyclopentadiene, ethylidene norbornene and vinyl norbornene can also be copolymerized.

Further, in addition to the monomer components described above, other copolymerizable monomer components may be contained in the copolymer in a small amount as long as the object of the present invention is not impaired.

The copolymer is prepared by using the monomer component of the formula (1) or the monomer component of the formula (1) and α-olefin and / or cyclic olefin described in detail above with a well-known Ziegler catalyst and a vanadium-based Ziegler catalyst. It is produced by polymerizing. More details are disclosed in a prior patent application filed by the applicant (for example, Japanese Patent Application No. 59-16995). A feature of the copolymer is that the monomer component of the formula (1) has a structure mainly represented by the formula (2) in the copolymer, whereby the iodine value in the copolymer is usually 5 or less. , Many are 1 or less. The adoption of this structure is also supported by ¹³ C-NMR.

By adopting this structure, the copolymer is chemically stable, is excellent in water resistance, chemical resistance such as alkali and acid, and is also excellent in solvent resistance, heat resistance and weather resistance. Also, it has an extremely low content.

The most preferred embodiment of the copolymer in the present invention contains the monomer component of the formula (1) and at least ethylene, and optionally contains other α-olefins and cyclic olefins. In this case, the molar ratio of the monomer component of formula (1) to ethylene is preferably in the range of 5/95 to 95/5, particularly preferably 40/60 to 90/10, and the third component, ie, 3 carbon atoms. When the above α-olefin and cyclic olefin are present, the molar ratio of the monomer component of formula (1) to the third component is in the range of 5/95 to 95/5, particularly 30/70 to 90/10. Is preferred.

When used in the optical material of the present invention, the molecular weight of the copolymer is 0.1 to 20 at the intrinsic viscosity [η] measured in decalin at 135 ° C.
dl / g in the range of 0.3 to 10 dl / g is preferred, and those having a crystallization temperature (X-ray diffraction method) of 5% or less, particularly 0%, are preferred. The copolymer having the above structure is substantially amorphous and thus has good transparency, and has no molding shrinkage and is excellent in dimensional stability. Moreover, it has excellent heat resistance. That is, the glass transition temperature (Tg) is usually 10 to 220 ° C.,
The heat deformation temperature is usually in the range of 0 to 210 ° C, and most is in the range of 50 to 200 ° C. Refractive index ▲ (n ²⁰ _D ) ▼
However, 1.47 to 1.58 are usually in the range of 1.50 to 1.56, and have a high refractive index in plastics.

Further, as a method for improving the copolymer, the third monomer component may be one obtained by using the above-mentioned polyene-based monomer and introducing an unsaturated bond into a side chain of the copolymer to cause crosslinking.

When such a copolymer is used as an optical material, the product has excellent dimensional accuracy and conforms to the intended dimensions.There is no modulation of optical characteristics due to distortion, and it has excellent heat resistance. It has excellent chemical and solvent resistance, so it is easy to handle, and because it has excellent water resistance, it does not need to be waterproofed. Indicate the features that you can do.

For example, when used for an optical disk substrate, a disk substrate is provided which can solve the conventional problems of heat resistance and water resistance of polymethyl methacrylate, and the problems of birefringence, dimensional stability, and water resistance of polycarbonate. Will be.
Therefore, the disk substrate of the present invention in which recording layers are laminated by various known methods can be used as a compact disk, a video disk, a write-once optical disk, a rewritable optical disk, and a magneto-optical disk. It can also be used as an optical card using a similar recording method.

More specifically, the optical disk of the present invention will be described. The substrate obtained by injection molding the above-described copolymer into a mold in which a stamper having irregularities corresponding to information bits is set has a high reflectance. Coated with a substance such as Ni, Al, Au, etc., a read-only disc that reads information using the reflection of laser light, or a groove as an information recording layer like a normal record board, There is a read-only disk for reading by utilizing a change in capacitance between a head to be scanned by scanning and an information bit provided at a lower portion of the groove, and an optical disk having a recording layer which is changed by light.
As a light-change type recording layer, one that uses changes in light reflectance and light transmittance resulting from an amorphous-crystal phase change by laser light irradiation, such as an As-Te-Ge system, and also uses a phase change Or TeOx (0 <X <2), or GdCo, TbFe, Gd
Those utilizing magnetization reversal, such as TbFe and ThdyFe, and also organic dyes can be used.

Further, for example, the copolymer may be used as a core layer or a clad layer and used as an optical fiber, an optical fiber connector, or an arrayed optical fiber in combination with various known optical fiber materials. In particular, when used as a clad layer, it has excellent water resistance, heat resistance, chemical resistance, and solvent resistance, so it fully protects the core layer and can be used in high-temperature areas that were impossible to reach with conventional polymethyl methacrylates. Become. Other plastics that become a core layer or a clad layer when constituting an optical fiber include polymethyl methacrylate and its derivatives, futsu-based polymers, poly-4-methylpentene-1 and its copolymers, and polyarylene. An additive may be blended for improving the adhesion, these may be modified, or a modified product may be blended.

Another use example is a plastic lens. Various shapes such as a spherical lens and a flat lens can be considered. This lens is used in various fields such as spectacles, sky glasses, loupes, and full-nel lenses used for lights or lamps of automobiles and bicycles.

Further, it may be used as an optical material for optoelectronics such as a light splitter, an optical waveguide, an OEIC substrate, and an optical filter. Furthermore, it can be used in fields such as window glass of buildings, automobile glass, window glass of railways, airplanes, and ships.

〔Example〕

Hereinafter, the contents of the present invention will be described in detail with preferred examples, but the present invention is not limited to these examples unless otherwise specified.

Example 1 [Production of copolymer] Using a two-glass polymerization vessel equipped with a stirring blade, ethylene and 2-methyl-1,4,5,8-dimethano-1,2,3,
4,4a, 5,8,8a-octahydronaphthalene (Hereinafter abbreviated as M-DMON) was carried out as follows.

That is, a 0.9% toluene solution of M-DMON was added from the upper part of the polymerization vessel so that the M-DMON concentration in the polymerization vessel became 60 g /.
VO (OC ₂ H ₅ ) Cl _{2 in} a toluene solution of 0.7 / hr so that the V concentration in the polymerization reactor becomes 0.5 mmol / as the catalyst and the Al concentration in the polymerization reactor becomes 2 mmol / , A toluene solution of Al (C ₂ H ₅ ) _1.5 Cl _1.5 is continuously supplied into the polymerization reactor at a rate of 0.4 / hr, while the polymerization liquid is always 1 in the polymerization reactor from the lower part of the polymerization reactor. Extract continuously. Also, from the upper part of the polymerization vessel, 5 ethylene is supplied at a rate of 25 / hr, N _{2 at} 80 / hr, and H ₂ at a rate of 2 / hr. The copolymerization reaction is performed by using a refrigerant.
Control was performed at 10 ° C. A small amount of methanol is added to the polymer polymerization liquid taken out from the lower part of the polymerization vessel or 5 times continuously to terminate the polymerization reaction, and then poured into a large amount of isopropyl alcohol to precipitate the produced copolymer. And washed. At this time, a copolymer was obtained at a rate of 30 g / hr. 100 ° C after washing
And dried under reduced pressure overnight.

Dust countermeasures are taken, for example, by washing the equipment and instruments used in this polymerization with dust-free acetone, and using the solvent used after distillation and purification after filtration.

According to ¹³ C-NMR analysis, the copolymer thus obtained contains 55 mol% of ethylene, and [η] measured in decalin at 135 ° C. is 0.64 dl / g. The loss elastic modulus (E ″) was measured at a heating rate of 5 ° C./min. The Tg determined from the peak temperature was 139 ° C., and the (n ²⁰ _D) measured with an Atsube refractometer was 1.537.

[Manufacture and properties of optical fibers]

Using a two-layer extruder, the above copolymer was used as a core layer and polytrifluoroethylene methacrylate (n ²⁰ _D) = 1.420,
Fibers with PTFMMA as clad layer were manufactured. The obtained fiber has a core of 1 mmφ and a cladding thickness of 0.2 mm.
The transmission loss measured by an optical loss measuring device manufactured by Anritsu Denki was 400 dB / km (λ = 780 nm).

Example 2 The copolymer of Example 1 was spun at 280 ° C. to a diameter of 0.6 mm, coated with a solution of polyvinylidene fluoride (PFVD) in methyl ethyl ketone, and dried. Table 1 shows the results.

Example 3 Instead of M-DMON in the polymerization of Example 1, 1,4,5,
8-dimethano-1,2,3,4,4a, 5,8,8a-octahydronaphthalene The same operation was performed except for using. Table 1 shows the results.

Example 4 Instead of M-DMON in the polymerization of Example 1, 6-ethylbicyclo [2,2,1] hept-2-ene The same operation was performed except for using.

Table 1 shows the results.

Example 5 Instead of polytrifluoroethyl methacrylate in Example 1, poly 4-methylpentene-1 (n ²⁰ _D
▼ = 1.46, TPX) was used in the same manner. Table 1 shows the results.

Example 6 The cyclic olefin monomer component of Example 1 and ethylene
Irgatcus is added to the copolymer obtained by copolymerizing 1010
0.1% by weight and 0.07% by weight of zinc stearate
C. and granulated with a 30 mmφ extruder.

A stamper for forming a bit for a CD (compact disk) prepared in advance is mounted on a mold, and the resin temperature is 300 ° C.
A mold temperature of 90 ° C. Injection pressure 680 kg / cm ^2, thickness 1.2
A 12 cmφ disk substrate of mm was obtained.

On a bit forming surface of this substrate, Al was vapor-deposited in a thickness of 1 μm under a vacuum degree of 2 × 10 ⁻⁶ Torr using a vacuum vapor deposition device (manufactured by Nippon Vacuum Engineering Co., Ltd.). Next, a UV-curable methyl methacrylate-based monomer was applied on the Al surface to form a cured film of 10 μm.

Table 2 shows the results of measuring the birefringence, water absorption, and light transmittance of the substrate obtained as described above. Here, the birefringence was measured using a He-Ne laser from a laser light source → a polarizer → 1 /
4λ → sample → polarizer → photo sensor
The results are shown in Table 2 in terms of Lettuce R (double pass value). The smaller the value is, the better the birefringence is. Further, the water absorption is based on a change in weight after being left for one month at 30 ° C. and a saturated vapor pressure. Light transmittance is self-spectrophotometer UV365
(Manufactured by Shimadzu Corporation) at a wavelength of 700 to 850 nm.

When the thus obtained CD was played on a Pioneer disk player, extremely good sound quality was obtained.

Example 7 In the same manner as in Example 6, a 30 cmφ disk plate having a thickness of 1.2 mm was formed using a laser vision stamper.
Table 2 shows the results.

Example 8 Example 6 except that a copolymer of ethylene and DMON was used.
Went as well. Table 2 shows the results.

Example 9 Example 6 except that a copolymer of ethylene and EBH was used.
Went as well. Table 2 shows the results.

Example 10 In Example 6, the spiral groove (0.8 μ width, 0.0 μm) was used.
A disk having a thickness of 1.2 mm and a diameter of 20 cm was formed using a stamper with a depth of 7 μm. Te was formed to a thickness of 100 mm on this disk using a sputter device manufactured by Nidec Anelva. Table 2 shows the results.

Example 11 An amorphous magnetic film was formed on the disk substrate of Example 10 using a mosaic target of Tb, Fe, and Co with a sputter device. The film composition was Tb ₃₀ (Co ₁₇ Fe ₈₃ ) ₇₀ atm%. The Kerr rotation angle measured by a He-Ne laser was 0.3 degrees.

Example 12 Ethylene and 2-ethyl-1,4,5,8-dimethano-1,2,3,
4,4a, 5,8,8a-octahydronaphthalene Using a lens mold having a diameter of 10 mm and a center part thickness of 3 mm using the above copolymer as a raw material, precision injection molding was performed at 280 ° C. (mold temperature 80 ° C.). The birefringence (letter plate: single pass) at the center was small, and the light transmittance was extremely good. Table 3 shows the results.

Example 13 Ethylene and 2,3-dimethyl-1,4,5,8-imetano-1,2,
3,4,4a5,8,8a-octahydronaphthalene Example 12 was carried out using the above copolymer. Table 3 shows the results.

EXAMPLE 14 Ethylene and 12-methyl hexa cyclo [6,6,1,1 ^3,6 1
^{10, 13} 0 ^2,7 0 ^9,14] -4-heptadecene Example 12 was carried out using the above copolymer. Table 3 shows the results.

Claims (9)

(57) [Claims] 1. A copolymer comprising (A) an α-olefin component having 2 to 10 carbon atoms and (B) a monomer component represented by the formula (1), wherein: (B) An optical material, wherein the monomer component comprises a copolymer having a structure represented by the formula (2). (Wherein R ^{1 to} R ¹² are hydrogen, an alkyl group having 1 to 4 carbon atoms or halogen, which may be the same or different, and R ⁹ or R ¹⁰ and R ¹¹ or R ¹² are N is 0, 1, 2, or 3, and R ^{5 to} R ⁸
Are repeated a plurality of times, they may be the same or different. ) (A) an α-olefin component having 2 to 10 carbon atoms, (B) a monomer component represented by the formula (1), and (C) a monomer component represented by the formula (C) having 5 to 11 carbon atoms. The optical material according to claim 1, comprising a copolymer containing a cyclic olefin component other than 1). 3. In the formulas (1) and (2), R ¹ to
R ¹² is hydrogen, a methyl group or an ethyl group;
The optical material according to claim 1 or 2, wherein the optical material is (1) or (2). 4. The optical material according to claim 1, wherein said α-olefin component is an ethylene component. 5. The optical material according to claim 1, wherein n = 1 in the monomer component represented by the formula (1). 6. The optical material according to claim 1, which is used for an optical fiber. 7. The optical material according to any one of claims 1 to 5, which is used for a disk substrate. 8. The optical material according to claim 1, which is used for a plastic lens. 9. The optical material according to claim 1, which is used for window glass.