JPH065321B2 - Optical lens - Google Patents

Description

TECHNICAL FIELD The present invention relates to an optical lens made of a polymer having a fluorine-containing alicyclic structure.

[Prior Art] Conventionally, there are several hundred types of inorganic glass having a refractive index of 1.46 to 2.0, but only fluorite is known to have a refractive index of 1.45 or less. Moreover, the inorganic glass is heavy and difficult to mold,
Cannot be processed into complicated shapes. On the other hand, plastic materials are lightweight, easy to mold, and have high impact resistance, and are now being widely used as optical lenses. Fluorine-based polymers such as CR-39, allyl resin and PFA are known as low refractive index plastic materials, but the refractive index of CR-39 and acrylic resin is not so low as around 1.49, and fluorine-based polymer is 1.35. The refractive index is low before and after, but it is opaque,
Sufficient molecular weight has not been obtained.

[Problems to be Solved by the Invention] The present invention solves the above-mentioned drawbacks of optical lenses made of conventional materials and is made of a plastic material having high transparency, sufficient strength and a low refractive index. The purpose is to provide a new optical lens.

[Means for Solving the Problems] The inventors of the present invention have conducted extensive studies based on the above-mentioned object, and as a result, have found that a thermoplastic polymer having a fluorinated alicyclic structure in its main chain has high transparency and low refractive index. It has been newly found that it is extremely advantageous as a material that has an optical index and is excellent in molding processability and provides an optical lens having sufficient strength.

Thus, the present invention has been completed based on the above findings, and newly provides an optical lens characterized by comprising a thermoplastic polymer having a fluorine-containing alicyclic structure in its main chain.

In the present invention, the thermoplastic polymer having a fluorinated alicyclic structure in its main chain can be exemplified in a wide range including those known or well known in the related art.

For example, the general formula (However, 1 is 0-5, m is 0-4, n is 0-1, l ⁺ m ⁺
n is 1 to 6, R is F or CF ₃ ), a general formula (However, o, p, q are 0-5, o ⁺ p ⁺ q is 1-6), general formula (However, R ₁ is F or CF ₃ and R ₂ is F or CF ₃ ) having a ring structure. Of these,
Polymers having the following ring structures are typical. However, the content of the present invention is not limited to these.

The methods for producing these polymers are as follows. However, it is not limited to these manufacturing methods.

1. By cyclopolymerization (USP 3418303, GB 1106344, etc.) (USP 3202643 etc.) 2. Using cyclic monomers (USP 3978030) In the above, a polymer having a perfluoroaliphatic ring structure is exemplified, but in the present invention, a part of the above-exemplified fluorine atom is substituted with another hydrogen atom or an organic group, or it is obtained by metathesis polymerization. And the like having a ring structure such as

Thus, the polymer having a specific ring structure in the present invention can be smoothly and advantageously obtained by the cyclopolymerization as described above,
In particular, by using a monomer having two polymerizable groups having different polymerizability in the molecule and having 2 to 7 atoms in the linear portion of the connecting chain connecting these two polymerizable groups,
Even if ultra-high pressure conditions or large dilution conditions are not adopted, by-products of gelation can be suppressed and the cyclopolymerization can proceed smoothly and advantageously.

As a monomer suitable for the cyclopolymerization as described above, first of all, it is desirable to have two carbon-carbon multiple bonds different in polymerizability. Usually, a carbon-carbon double bond is adopted, and two multiple bonds different in kind or structure are adopted. For example, a fluorine-containing monomer having two non-symmetrical multiple bonds, a vinyl group and an allyl group, a vinyl ether group and a vinyl group, a fluorine-containing multiple bond and a hydrocarbon multiple bond, a perfluoro multiple bond and a partially fluorinated multiple bond. Such as. Secondly, the number of atoms in the straight chain portion of the connecting chain connecting these two carbon-carbon multiple bonds is 2 to 7
Is desirable. The number of atoms in the straight chain portion of the connecting chain is 0
In the case of 1 to 1, the cyclopolymerization hardly occurs, and in the case of 8 or more, the same applies. Usually, it is preferable that the number of atoms is 2 to 5. Further, the connecting chain is not limited to a straight chain, may have a side chain structure or a ring structure, and the constituent atoms are not limited to carbon atoms, and may include hetro atoms such as O, S, and N. good. Third, the fluorine content is
10% by weight or more is desirable. When the fluorine content is too low, it becomes difficult to exhibit the specificity of the fluorine atom. As a matter of course, a perfluoro monomer is preferably used.

Specific examples of the above specific fluorine-containing monomer include CF ₂ = CFOCF ₂ CF = CF ₂ , CF ₂ = CFOCF ₂ CF ₂ CF = CF ₂ , CF ₂ = CF
OCF ₂ CF = CH ₂ , CF ₂ = CFOCF ₂ OCF ₂ CF = CF ₂ , CF ₂ = CFOCF ₂ CF ₂ CH = CH ₂ , (However, x is an integer of 1 to 4), Can be exemplified. In the present invention, one having one vinyl ether group of CF ₂ = CFO- is preferably adopted in view of polymerization reactivity, cyclopolymerization property, gelation suppression, etc., and particularly perfluoroallyl vinyl ether (CF ₂ = CFOCF ₂ CF
= CF ₂ ) and perfluorobutenyl vinyl ether (CF _{2
= CFOCF 2 CF 2 CF = CF} 2) it may be mentioned as preferred examples.

The above monomer components may be used alone or in combination of two or more, and further, there is no problem in copolymerizing in combination with other copolymer components so long as the essence of these components is not impaired. .

The other monomer to be copolymerized is not particularly limited as long as it is a monomer having radical polymerizability, and a fluorine-containing type, a hydrocarbon type and the like can be widely exemplified. As a matter of course, one of these other monomers may be radically copolymerized with a monomer capable of introducing the specific ring structure, or two or more appropriate monomers may be used in combination to carry out the above copolymerization reaction. May be done. In the present invention, it is usually desirable to select a fluorine-containing monomer such as fluoroolefin or fluorovinyl ether as the other monomer. For example, tetrafluoroethylene,
Perfluoromethyl vinyl ether, perfluoropropyl vinyl ether, and perfluorovinyl ether having a functional group such as a carboxylic acid group and a sulfonic acid group are preferable specific examples, such as vinylidene fluoride, vinyl fluoride, and chlorotrifluoroethylene. Can also be illustrated.

The copolymer composition, in order to take advantage of the characteristics of the specific fluorine-containing alicyclic structure intended in the present invention, the composition of the cyclic structure is preferably 20% or more, more preferably 40
% Or more is desirable.

In addition, various additives such as an antioxidant and an ultraviolet stabilizer may be added to the fluoropolymer in the present invention in order to improve practicality. Furthermore, by combining a polymer having the above-mentioned structure or its precursor monomer with a polymer having a high refractive index, or a combination of a monomer (copolymerization, blending, etc.), an optical lens having a large refractive index distribution can be obtained. It is applicable.

Since the polymer having a specific ring structure in the present invention is soluble in a fluorine-based solvent or the like, a thin optical lens can be prepared by casting from a solution or the like. Further, since the thermoplastic resin has a low melting temperature and a relatively low melt viscosity, hot melt molding is easy.

The solvent to be used is not limited as long as it dissolves the above-mentioned polymer, but perfluorobenzene, “Aflude” (trade name: fluorine-based solvent manufactured by Asahi Glass Co., Ltd.), “Fluorinert” (trade name: manufactured by 3M Company) (A liquid containing perfluoro (2-butyltetrahydrofuran)), trichlorotrifluoroethane and the like are preferable. . As a matter of course, two or more appropriate types can be used in combination as a solvent. Particularly in the case of a mixed solvent, a hydrocarbon type, a chlorinated hydrocarbon, a fluorinated hydrocarbon, an alcohol and other organic solvents can be used together. The solution concentration is 0.01 wt% to 50 wt%, preferably 0.1 wt% to 200.1 wt%.

When hydrophilicity is required on the surface of a contact lens or the like, the surface can be treated with plasma, grafted with a hydrophilic monomer, or copolymerized for use.
Furthermore, in order to improve the circulation of tears and enhance metabolism, it is possible to form an appropriate groove on the inner surface of the lens because the refractive index of the resin is close to that of tears.

Fluorine-containing polymer having a specific ring structure in the present invention, compared to the optical lens material used conventionally,
The refractive index is as low as 1.49 or less, and it is transparent regardless of whether it is a fluororesin, and those having a high fluorine content can achieve a low refractive index of 1.40 or less. Therefore, it can be applied to various optical lenses, for example, a contact lens that is stain resistant and has a high refractive index of 1.336 and a high oxygen transmission rate, or a low Petzval sum and an achromatic condition. It can be used as a refractive index lens or the like. Furthermore, since it is physically and chemically stable, it can be used as an artificial lens lens.
Further, by providing a refractive index distribution, it can be used as a low aberration lens, for example, a lens for collimating light from a light emitting element such as a semiconductor laser, a lens for converging parallel light flux, or an artificial crystalline lens with a wide field of view. Other,
It is also useful as various optical lenses that have been conventionally used, such as optical communication lenses and pickup lenses, by taking advantage of transparency and weather resistance and moisture resistance.

[Operation] In the present invention, the thermoplastic polymer having a fluorinated alicyclic structure in its main chain shows low transparency even though it is a fluororesin because it has little crystallinity or almost no crystallinity. It also has a high light transmittance, and because it is a fluorine-containing polymer, it has a lower refractive index and higher oxygen permeability than ordinary hydrocarbon-based resins, and also has moisture resistance, weather resistance, and chemical resistance. Considered to be excellent. However, it goes without saying that the above description is intended to help understanding of the present invention and does not limit the present invention in any way.

[Examples] Next, examples of the present invention will be described more specifically, but it goes without saying that the description does not limit the present invention.

Synthesis Example 1 35 g of perfluoroallyl vinyl ether, 5 of trichlorotrifluoroethane (hereinafter abbreviated as R-113)
g, 150 g of ion-exchanged water, and as a polymerization initiator Was placed in a pressure-resistant glass autoclave having an internal volume of 200 ml. After purging the system with nitrogen three times, suspension polymerization was carried out at 26 ° C. for 23 hours. As a result, 28 g of a polymer was obtained.

When the infrared absorption spectrum of this polymerization resistance was measured,
1660 cm ^-1 , 1840 cm due to double bond in monomer
There was no absorption near ^-1 . When this polymer was dissolved in perfluorobenzene and the ¹⁹ F NMR spectrum was measured, the spectrum showing the following repeating structure was obtained.

The intrinsic viscosity [η] of this polymer is "Fluorinert" FC-7
It was 0.530 at 30 ° C. in 5 (trade name: a liquid containing perfluoro (2-butyltetrahydrofuran) manufactured by 3M as a main component, hereinafter abbreviated as FC-75). The glass transition temperature of the polymer is 69 ° C., and it is a tough and transparent glassy polymer at room temperature. The 10% thermal decomposition temperature was 462 ° C, the polymer was colorless and transparent, the refractive index was low at 1.34, and the light transmittance was high at 95%.

Synthesis Example 2 20 g of 1,1,2,4,4,5,5-heptafluoro-3-oxa-1,6-heptadiene and 40 g of R-113 were placed in a nitrogen-substituted three-necked flask to initiate polymerization. As an agent (20 mg) was added, the atmosphere in the system was replaced with nitrogen, and then polymerization was carried out at 18 ° C. for 10 hours. As a result, 10 g of a polymer was obtained. This polymer is a polymer that dissolves in R-113, and the intrinsic viscosity [η] at 30 ° C in meta-xylene hexafluoride is 0.
It was 96. It was confirmed by ¹⁹ FNMR and ¹ HNMR that the polymer had the following repeating structure.

The polymer was colorless and transparent, had a low refractive index of 1.36 and a high light transmittance of 93%.

Examples 1 and 2 Using 3 g of each of the polymers obtained in Synthesis Examples 1 and 2, injection molding (cylinder temperature 250 ° C., injection pressure 800
A cylindrical body having a diameter of 10 mm and a thickness of 20 mm was obtained by kg / cm ² and a mold temperature of 40 ° C. This columnar body was cut into a disk having a thickness of 5 mm, and an artificial lens was prepared using a dedicated lathe.

Even if this artificial lens was immersed in physiological saline containing fatty acid at 37 ° C. for 1 week, the transparency did not change at all. Also,
This artificial crystalline lens was irradiated with an ultraviolet ray for 150 minutes from a position of 10 cm with a 400 W high-pressure mercury lamp, but no change was observed.

Example 3 Using about 0.5 g of the polymer obtained in Synthesis Example 1, Example 1
By the same injection molding as in ~ 2, a cylindrical body having a diameter of 10 mm and a thickness of 7 mm was obtained. A contact lens was manufactured from this cylindrical body by cutting.

This contact lens had a visible light transmittance of 95% and an oxygen permeability of 3.9 × 10 ⁻¹⁰ cm ³ · cm / cm ² · sec · cmHg. This contact lens was subjected to a wearing test of 5 male rabbits weighing 2.5 kg for 16 hours a day for 7 days, but no hyperemia or secretion was observed in any of the 5 rabbits. When the visible light transmittance of this test piece was measured, no decrease in transmittance was observed.

Example 4 The polymer obtained in Synthesis Example 1 was injection molded into a concave lens mold. The obtained concave lens did not absorb water even when immersed in water at 60 ° C. for 1 week, and had good weather resistance. The Abbe number measured by an Abbe refractometer was about 90.

Example 5 The polymer obtained in Synthesis Example 1 was injection-molded into a mold for an optical pickup objective lens for CD to obtain an objective lens. This objective lens is exposed to high temperature of 50 ℃ × 95% for 4 hours at 30 ℃.
After leaving it for 10 cycles in a temperature / humidity cycle test consisting of 4 hours under a low temperature condition of 30%, it was mounted on a compact disc pickup, but no tracking servo error, focus servo error, etc. occurred at all, and it operated well. .

Example 6 35 of perfluoroperfluorobutenyl vinyl ether
g, 5 g of R-113, 150 g of ion-exchanged water, and 90 mg of ((CH ₃ ) ₂ CHOCOO) ₂ as a polymerization initiator in an internal volume of 200 ml.
It was placed in a pressure-resistant glass autoclave. After purging the system with nitrogen three times, suspension polymerization was carried out at 40 ° C. for 22 hours. As a result, 28 g of a polymer was obtained.

The intrinsic viscosity [η] of this polymer is "Fluorinert" FC-7
It was 0.05 in 5 at 30 ° C. Glass transition temperature of polymer is 108 ℃
It is a tough and transparent glassy polymer at room temperature. The 10% thermal decomposition temperature is 465 ° C and the refractive index is 1.34.
Was low.

Moreover, when the ¹⁹ F NMR spectrum was measured, a spectrum showing the following repeating structure was obtained.

The polymer obtained above was injection-molded in a mold for an optical pickup objective lens for CD to obtain an objective lens. This objective lens mold was injection-molded to obtain an objective lens.
This objective lens was exposed to 70 ° C x 95% high temperature for 4 hours,
After leaving it for 10 cycles in a temperature / humidity cycle test consisting of 4 hours at a low temperature of 30 ° C x 30%, it was mounted on a compact disc pickup.
Focus servo error did not occur at all, and it worked well.

[Advantages of the Invention] The present invention is excellent in obtaining an optical lens having a low refractive index, transparency, and good weather resistance by employing a thermoplastic polymer having a fluorine-containing alicyclic structure in its main chain as a material. It is also recognized that those having a high fluorine content also have heat resistance, chemical resistance, moisture resistance, and stain resistance, and that the refractive index can be 1.04 or less.

Claims (1)

[Claims] 1. An optical lens comprising a thermoplastic polymer having a fluorinated alicyclic structure in its main chain.