JPH03155868A - Intra-ocular lens - Google Patents

Abstract

PURPOSE:To provide the intra-ocular lens which has excellent bioadaptability and UV absorptivity, is chemically stable and has the heat resistance to allow the steam sterilization in an autoclave by providing a lens part and a fixing part for fixing the lens pat into the eye and constituting the lens part of colorless transparent polyimide having a specific chemical structure. CONSTITUTION:This lens has the lens part and the fixing part for fixing the lens part into the eye. The lens part is constituted of the colorless transparent polyimide essentially consisting of the repeating unit expressed by general formula (1). In the formula, X denotes the group selected from the groups consisting of a directly coupled 1 to 10C bivalent chain hydrocarbon group, perfluoro(1- methyl ethylidene) group, carbonyl group, and thio group and the bond position of the nitrogen atom of the imide ring is a metha or para position with an ether bond. The lens part has the bioadaptability, is chemically inert, has >=1.6 refractive index and completely absorbs UV rays of 200 to 380nm region.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention restores visual acuity by inserting the crystalline lens into the anterior chamber or retrograde part of the eye, which has become aphakic after lens removal surgery by Hirohiro Shiro. Intraocular lenses that make it possible to
(artificial crystalline lens).

[Prior art] Methods for restoring the vision (forced refraction) of patients who have become aphakic after lens removal surgery due to cataracts, etc. include (2) wearing contact lenses, and (3) using an artificial crystalline lens. Internal lens implantation is being performed.

(1) Although visual acuity can be obtained with eyeglass correction after surgery, the patient suffers from narrowing of the visual field (enlargement of the retinal image) and jack-in-the-box phenomenon, and the patient himself or herself is unable to use the glasses until they can actually be used. , must be endured for a certain period of time. Moreover, especially in the case of a monocular aphakic eye, binocular vision cannot be obtained due to asymmetric vision.

(2) Wearing contact lenses is effective against such anisotropy, and high water content soft contact lenses have now been developed, making continuous wear possible, and this problem is being solved. are often elderly,
Because they are difficult to handle, even if they are prescribed after surgery, few people actually wear them. Thus, correction using glasses and contact lenses cannot be said to be a preferable method.

(3) Artificial lens implantation is a method that has already been used for 30 years, and the artificial lens, so-called intraocular lens, has little enlargement of the retinal image, no visual field constriction or ring-shaped scotoma, and provides binocular vision function. (This is especially advantageous compared to glasses for monocular anhydrous black eyes), there is no need for a period of getting used to it, and -
It has many advantages as it does not need to be removed once it has been transplanted. In recent years, with the development of microscopes, ultrasound scalpels, etc., transplant surgery techniques have improved, and the shape and material of intraocular lenses have also been improved. is also important.

In this way, intraocular lenses are very effective in correcting vision, but because they are foreign bodies in the eye, they can cause ocular complications, which can lead to corneal endothelial disorders and eventually lead to decompensation and blindness. There are also cases where this is the case. Therefore, the material for the intraocular lens is required to be non-toxic to the living body, have excellent biocompatibility, and not be subject to modification or deterioration from the living body.

By the way, natural light includes wavelengths in the ultraviolet, visible, and infrared regions, and there is a risk that a large amount of ultraviolet rays passing into the eyes may cause damage to the retina. The crystalline lens of the eye preferentially absorbs the ultraviolet rays and also plays the role of protecting the retina, so in the aphakic eye described above, the transmission of ultraviolet rays becomes a major problem. Therefore, it is desired that the material for the intraocular lens absorbs ultraviolet rays in the 200-380 nm range and is transparent to visible light in the 380-780 nm range. moreover,
If the intraocular lens itself is heavy, it will put a strain on the eye.
It is desired that the material has essentially a low specific gravity and a high refractive index so that the lens thickness can be made thin.

For example, glass has a high refractive index and can absorb ultraviolet rays, but it is difficult to process and has a high specific gravity (2,5), which makes the lens itself heavy and puts a greater burden on the eye, so intraocular lenses are used. There is a problem with using it. Natural or synthetic crystals such as sapphire, ruby, corundum, silicon, and diamond have the ability to absorb ultraviolet rays, but like glass, they are difficult to process and have a high specific gravity, so they are not suitable for intraocular lenses. Appropriate.

Currently, the most commonly used intraocular lenses are:
This P, which is polymethyl methacrylate (PMMA)
MMA has excellent optical properties and is resistant to acids and alkalis.

It has the characteristics of being resistant to organic solvents and resistant to changes over time.

However, the above PMMA has a glass transition temperature (Tg)
Since the temperature is low at 100°C or less and lacks thermal stability, autoclave sterilization using steam cannot be performed. This is because the material becomes soft and deformed, making it unusable. Therefore, intraocular lenses made of PMMA are sterilized using ethylene oxide gas, etc.
If gas remains inside the lens and enters the eye, it may cause inflammation of the mucous membranes. Therefore, degassing is an essential step in the above gas sterilization method.
Since this process requires about two weeks, the cost is high and the method is currently more expensive than the steam autoclave sterilization method. Furthermore, since PMMA transmits a considerable amount of ultraviolet light, as mentioned above, ultraviolet light may cause damage to the retina. For this reason, JP-A-60-
As seen in No. 232149, it is attempted to solve the above problem by adding an ultraviolet absorber. However, adding an ultraviolet absorber in this way may impair the transparency of visible light, and the ultraviolet absorber may gradually leach out of the lens, potentially having an adverse effect on living organisms, so this is the preferred method. It cannot be said that
Moreover, the above-mentioned PMMA has a refractive index of about 1.
Because the size of the eye is small, the lens becomes thick, which can cause complications if the lens sticks to the pupil.

As described above, although PMMA has many advantages, it also has many disadvantages, so there is a demand for a material that can be sterilized in an autoclave, can absorb ultraviolet rays, and has a high refractive index.

Polysulfone is a synthetic resin that can replace PMMA.

Polyarylate, polyetherimide, etc. are being considered. The polysulfone has a high refractive index, has ultraviolet absorbing properties, and has a softening point of 175°C,
Autoclave sterilization is possible, but it cannot be put into practical use due to difficulties in processability, and polyarylate also has a high refractive index.

It has ultraviolet absorbing properties and can be sterilized in an autoclave, but like the above-mentioned polysulfone, it has problems with processability and is difficult to put into practical use. In addition, existing polyetherimide has a high refractive index, ultraviolet absorption, autoclave sterilization, and good processability, but it is colored yellow or yellowish brown, and the amount of visible light transmitted is too low. ,
It is impossible to use it as an intraocular lens.

In this way, although PMMA has the drawbacks mentioned above, no alternative material has been found, so sterilization is performed by applying an expensive gas sterilization method.
In reality, intraocular lenses are used as materials for intraocular lenses by adding ultraviolet absorbers that may have adverse optical and biological effects. Seven things were made in consideration of the circumstances.
The purpose of the present invention is to provide an intraocular lens that has excellent biocompatibility, ultraviolet absorption, low specific gravity, high refractive index, chemical stability, and heat resistance that allows autoclave steam sterilization.

More specifically, it can be easily processed into a thin lens shape by machining or molding, and has a specific gravity of 1.
7 or less, preferably 1.5 or less, and the refractive index is 1.5.
The above is preferably 1.6 or more, and furthermore, it is chemically stable and biocompatible, absorbs ultraviolet rays that are dangerous to the retina, and has heat resistance that allows autoclave steam sterilization. The objective is to provide intraocular lens materials that are

[Means for Solving the Problems] The above object is provided with a lens portion and a fixing portion for fixing the same in the eye, wherein the lens portion contains a repeating unit represented by the following general formula (I). This was achieved with an intraocular lens composed of colorless and transparent polyimide as its main component.

(wherein, X is a direct bond, a divalent chain hydrocarbon group having 1 to 10 carbon atoms, a perfluoro(1-methylethylidene) group,
It represents a group selected from the group consisting of a carbonyl group and a thio group, and the bonding position of the nitrogen atom of the imide ring is meta or para to the ether bond. ) The present inventors first discovered that polyimide has inherent long-term heat resistance,
Chemical Resistance 1 In addition to mechanical strength, a polyimide film having an extremely high light transmittance as a basic structure having the skeleton represented by (I) above was disclosed (Japanese Patent Laid-Open No. 62-1
85715).

The present inventors have conducted intensive studies to use the polyimide represented by the above formula (I) as an intraocular lens, and as a result, have arrived at the present invention.

In other words, in order to obtain an intraocular lens superior to the PMMA described above, the present inventors repeatedly investigated a series of resins, and found that aromatic polyimide completely absorbs ultraviolet rays and has a low refractive index. It was found that it has a large size (1.6 or more) and sufficient heat resistance to perform autoclave steam sterilization, and has superior properties compared to PMMA. However, since existing aromatic polyimides are colored yellow or brown, they absorb not only ultraviolet rays but also a considerable portion of visible light. Therefore, the present inventors developed an aromatic polyimide that does not absorb visible light. As a result of repeated research into the development of ophthalmic polyimides, we found that using the aromatic polyimide represented by the general formula (I) above, it is possible to completely absorb ultraviolet rays while transmitting most of the visible rays, resulting in a virtually transparent intraocular material. A lens was obtained, and it was further discovered that this material, like conventional aromatic polyimides, has the properties required for intraocular lenses and is also excellent in biocompatibility, leading to the present invention.

That is, the intraocular lens of the present invention has a lens portion that is biocompatible, chemically inert, not subject to modification or deterioration from the living body side, has a refractive index of 1.6 or more, and has a refractive index of 1.6 or more.
Completely absorbs ultraviolet rays in the ~380nm region, and
Constructed from a colorless and transparent polyimide whose main component is a repeating unit represented by the general formula (I), which is substantially transparent to visible light in the ~780 nm region and has heat resistance that can withstand autoclave sterilization. This is what has been done.

The intraocular lens of the present invention includes a lens portion and a fixing portion for fixing the lens portion within the eye. The lens portion is made of a colorless and transparent polyimide whose main component is a repeating unit represented by the general formula (I). Such a colorless and transparent polyimide is made of, for example, 3,3°,4,4°-diphenyl ether tetracarboxylic dianhydride represented by the following general formula () and the general formula (I[r) (wherein,
X has the same definition as in formula (I), and the bonding position of the amine group is the meta or bara position relative to the ether bond. ) Formula (IV) obtained by reaction with an aromatic diamino compound represented by (rV) (wherein, It is obtained by further dehydrating and cyclizing a polyamic acid having a repeating unit represented by the following (meta position or rose position).

As the aromatic diamino compound, bis r4-(3-
aminophenoxy) phenylcomethane, bis(4-(4
-aminophenoxy)phenyl 1methane, 1.1-bis(4-(3-aminophenoxy)phenyl]ethane, 1
．． 1-bis(4-(4-aminophenoxy)phenyl)
Ethane, 1,2-bis(4-(3-aminophenoxy)
phenyl]ethane, 1,2-bis(4-(4-aminophenoxy)phenyl 1methane, 2,2-bis(4-(3
-aminophenoxy)phenyl]propane, 2.2-bis(4-(4-aminophenoxy)phenyl)propane, 2.2-bis[4-(3-aminophenoxy)phenyl]cobutane, 2.2-bis(4-(3-aminophenoxy)phenyl)propane, 4-(4-aminophenoxy)phenylcobutane, 2,2-bis(4-(3-aminophenoxy)phenylj-1,1,1,3,3,3-
Hexafluoropropane, 2,2-bis(4-(4-aminophenoxy)phenyl) -1,1,1,3,3,
3-hexafluoropropane, 4.4°-bis(3-aminophenoxy)biphenyl, 4,4°-bis(4-aminophenoxy)biphenyl, bis(4-(3-7minophenoxy)phenyl 1 ketone, bis [4-(4-aminophenoxy)phenyl 1 ketone, bis(4-(3-aminophenoxy)phenyl] sulfide, bis[4-(
Examples include 4-aminophenoxy)phenyl sulfide.

Each of the above aromatic diamines may be used alone, or
They may be used in appropriate combinations.

By combining the above-mentioned 3.3', 4.4°-diphenyl ether tetracarboxylic dianhydride and the above-mentioned aromatic diamine, it is possible to obtain a compound containing the repeating unit represented by the general formula (I) as the main component for the first time. This results in a colorless and transparent polyimide. Here, the term "main component" is meant to include cases where the entire component consists only of the main component. In this case, the greater the content of the repeating unit represented by the above general formula (I), which is the main component of the colorless and transparent polyimide, the more colorless and transparent the resulting polyimide becomes. However, the repeating unit represented by the above general formula (I) is 8o
If the content is mol% or more, at least the ultraviolet absorbency and visible light transmittance determined by this invention are ensured, so within that range, the above 3.3', 4.4°-diphenyl ether tetracarboxylic dianhydride Aromatic tetracarboxylic dianhydrides other than those mentioned above and diamine compounds other than the above-mentioned aromatic diamines can be used. However, the preferred range of the content of the repeating unit represented by the above general formula (I) is 80 mol% or more, and the most preferred range is 95 mol% or more.

Examples of the other aromatic tetracarboxylic dianhydrides include pyromellitic dianhydride, 3,3°, 4′-biphenyltetracarboxylic dianhydride, 2°3.3°, 4′-biphenyl Tetracarboxylic dianhydride, 3.3″,
4.4'-benzophenonetetracarboxylic dianhydride, 4,4°-bis(3,4-dicarboxyphenoxy)diphenylsulfone dianhydride, 3°3°, 4.4'
- diphenylsulfone tetracarboxylic dianhydride, 2.
2-bis(3,4-dicarboxyphenyl)hexafluoropropanide anhydride, 2,3.6.7-naphthalenetetracarboxylic dianhydride, 1.2.5.6-naphthalenetetracarboxylic dianhydride , l, 4.5.8-naphthalenetetracarboxylic dianhydride, which can be used alone or in combination.

In addition, other diamino compounds include 4゜4゛-diaminodiphenyl ether, 3.4゛-diaminodiphenyl ether, 3,3゛-diaminodiphenyl ether, 4.4゛-diaminodiphenyl sulfone, 4.4゛-diaminodiphenyl ether,
゛-diaminodiphenylmethane, 3.3゛-diaminodiphenylmethane, 4.4゛-diaminobenzophenone, 3.3゛-diaminobenzophenone, 4,4゛-
Diaminodiphenylpropane, 3,3'-diaminodiphenylpropane, p-phenylenediamine, m-phenylenediamine, benzidine, 3,3°-dimethylbenzidine, 4゜4゛-diaminodiphenylthioether,
Examples include 3.3°-diaminodiphenylthioether, which can be used alone or in combination.

The colorless and transparent polyimide that is the material for the intraocular lens of this invention is synthesized from polyamic acid by polymerizing the above-mentioned aromatic tetracarboxylic dianhydride and diamino compound in an organic polar solvent at a temperature of 80°C or less. Then, use this polyamic acid solution to form a shaped body of a desired shape, and place this shaped body in air or an inert gas.
It is obtained by evaporating and removing the organic polar solvent at a temperature of 50 to 350° C. under normal pressure or reduced pressure, and simultaneously dehydrating and ring-closing the polyamic acid to form a polyimide. It can also be obtained by a chemical imidization method in which the polyamic acid solution is imidized using a base such as pyridine and a dehydrating agent such as acetic anhydride to form polyimide.

In the above method, it is also possible to isolate the polyamic acid by reprecipitation and then dehydrate and ring-close it by heating or using a chemical imidizing agent to obtain a polyimide. Furthermore, it is also possible to obtain a polyimide by directly heating the solution after polyamic acid synthesis to 100° C. or higher to imidize it, and then discharging the solution into a precipitate or a poor solvent. In this case, although filtration and washing are required, substantially the same colorless and transparent polyimide is obtained.

Examples of organic solvents used in this reaction include N,N-dimethylformamide, N,N-dimethylacetamide,
N,N-diethylacetamide, N,N-dimethylmethoxyacetamide, N-methyl-2-pyrrolidone, 1.
3-dimethyl-2-imidazolidinone, N-methylcaprolactam, 1,2-dimethoxyethane, bis(2-methoxyethyl)ether, 1,2-bis(2-methoxyethoxy)ethane, bis(2-(2 -methoxyethoxy)ethyl)ether, tetrahydrofuran,! , 3-dioxane, 1,4-dioxane, pyridine, picoline,
quinoline, dimethyl sulfoxide, dimethyl sulfone,
Examples include tetramethylurea, hexamethylphosphoramide, phenol, cresol, and helophenol. Further, these organic solvents may be used alone or in combination of two or more.

In addition, when using the suitable organic polar solvent exemplified above, a poor solvent or a good solvent that does not impair transparency, such as ethanol, toluene, benzene, xylene, dioxane, tetrahydrofuran, nitrobenzene, etc., is added to the solvent.
One or more solvents may be used in combination as appropriate within a range that does not impair solubility; however, if these solvents are used in large amounts, they will have a negative effect on the solubility of the polyamic acid produced. Therefore, it is appropriate to limit the amount used to 50% by weight of the entire solvent, and most preferably to 30% by weight.

When producing colorless and transparent polyimide as described above, the intrinsic viscosity (logarithmic viscosity) of the polyamic acid solution is 0.2 to
It is preferably in the range of 5.0.

More preferred is 0.3 to 2.0. The above intrinsic viscosity is 0.5g/100m in N,N-dimethylacetamide.
This is a value measured at a temperature of 1. If the intrinsic viscosity is too low, the resulting intraocular lens will have a low mechanical strength, which is undesirable. If the intrinsic viscosity is too high, it will be difficult to form the polyamic acid solution into an appropriate shape, or the polyamic acid solution will be difficult to form. This is not preferred because it makes isolation difficult. Furthermore, when the obtained polyimide powder is extruded or injection molded, the melt viscosity becomes too high, resulting in poor processability.

The concentration of the polyamic acid solution is not particularly limited and is appropriately determined from the viewpoint of workability and the like.

Here, the logarithmic viscosity is a value calculated using the following formula.

Logarithmic viscosity=1n(η/ηo)/c In the formula, In is the natural logarithm, η is the solvent N, and η is the viscosity measured at 35°C of a solution of 0.5 g of polyamic acid dissolved in 100 ml of N-dimethylacetamide. is the viscosity of the solvent, measured at 35° C., and C is the solution concentration of the polymer in g of polyamic acid per 10 C) nl of solvent.

For example, the following method can be used to produce an intraocular lens using the colorless and transparent polyimide obtained as described above.

The first method is to prepare a polyimide film in advance and stack several polyimide films on top of each other to obtain a plate-shaped molded product with a desired thickness. That is, the polyamic acid solution is cast onto a mirror-finished glass plate, stainless steel plate, etc. to a certain thickness, and gradually heated at a temperature of 100 to 350°C to dehydrate and ring-close the polyamic acid to imide. A polyimide film is obtained by In film formation from a polyamic acid solution, the removal of the organic polar solvent and the heating for imidization of the polyamic acid may be performed continuously,
Alternatively, these steps may be performed under reduced pressure or in an inert gas atmosphere. Another method for forming a polyimide film is to cast the above polyamic acid solution onto a glass plate or the like at 100 to 150°C. A film is formed by heating and drying for 30 to 120 minutes, and this film is immersed in an organic solvent or aqueous solution containing a base such as pyridine and a dehydrating agent such as acetic anhydride to perform an imidization reaction with the desolvent. This is a method for producing a polyimide film, and a polyimide film can also be obtained by this method.

The necessary number of polyimide films obtained in this manner were stacked to form a plate-shaped molded product with a constant thickness, and the film was heated at 20°C.
0.1 to 400℃, pressure 0.5 to 10t/cm"
A transparent polyimide molded product is obtained by performing hot-press molding for 10 hours.

An intraocular lens is obtained by polishing this into an intraocular lens shape using a polishing device.

The second method is a method in which polyimide powder or polyamic acid powder is directly heat-molded. That is, a polyamic acid solution is poured into a poor solvent such as water or methanol to re-precipitate the polyamic acid and then recovered, followed by dehydration ring closure and imidization by heating at a temperature of 100 to 350°C, followed by pulverization. A colorless and transparent polyimide powder was obtained, and this powdered polyimide was heated in the same manner as above at a temperature of 200 to 400°C.
A transparent polyimide molded body is obtained by hot-pressing at a pressure of 0.5~L Ot/am'' for a time of Q, l~to, which can be polished into an intraocular lens in the same manner as above. .

In the second method above, another method for obtaining a colorless and transparent polyimide powder is to heat the polyamic acid solution to 100 to 200°C while stirring, or to use a base such as pyridine and a dehydrating agent such as acetic anhydride. There is a method in which polyamic acid is converted into polyimide and further precipitated out of the system as a precipitate. In this case, it is possible to use it for molding only by washing and drying.

In particular, as a method with good workability and productivity, many of the polyimides of the present invention exhibit thermoplasticity and very good fluidity, so a round bar or flat plate is made by extrusion molding, and then the desired shape is formed by cutting. A shaped body is obtained.

Furthermore, injection molding is also a preferable method from the viewpoint of productivity.

In this way, an intraocular lens is produced using a colorless and transparent polyimide film or polyimide powder.

The third method is not a method using thermoforming like the first and second methods described above, but a method of obtaining a polyimide molded body directly from polyamic acid. Conventional drying methods cannot suppress foaming, and 15
It is difficult to obtain a homogeneous polyimide molded body with a diameter of 0 μm or more.

However, by leaving the polyamic acid solution under reduced pressure for a long time and heating it from the inside using far infrared rays or microwaves, it is possible to obtain a polyimide molded article with a size of 500 μm or more without foaming. That is, by using such far infrared rays and microwaves, a homogeneous polyimide molded body can be obtained directly from polyamic acid.

In order to manufacture an intraocular lens from a polyimide molded body obtained by the above three types of methods, it can be performed, for example, by machining. In other words, this can be done by making a lens by performing curved polishing according to the power, then NC processing (numerically controlled processing) the hole for attaching the fixing part, and welding the fixing part to this hole by spot heating. can. An example of an intraocular lens obtained in this way (an intraocular lens to be implanted in a retrograde human eye) is shown in Figs. 1 and 2, where 1 is the lens part and 2 is A position adjustment hole 3 is formed along the circumference at the peripheral edge of the lens portion l;
This is a fixation part for fixing the inside of the eye.

The shape of the fixing part 3 is wide-ranging and can be changed as necessary. As the material of the fixing part 3, polypropylene, polyvinylidene fluoride, etc. are often used. However, with the intraocular lens of this invention,
These materials may be used, or other materials may be used. Furthermore, colorless and transparent polyimide, which is the same material as the lens portion, may be used.

In addition, as described above, instead of providing the lens part and the fixing part separately and combining them, the lens part and the fixing part may be formed by integrally molding. Since there is no joint between the two, a situation in which the fixing part comes off from the lens part can be avoided.

The intraocular lens thus obtained is completely different from those made using conventional aromatic polyimide, and has extremely high transparency.

The colorless and transparent polyimide used in this invention is
In the case of a film-like molded product with a film thickness of 50 μm, visible light (5
00 nm) is 80% or more, and the yellowness index is 30 or less. The lens portion of the intraocular lens of this invention is 0.5 mm.
In case of thickness, total amount of visible light transmitted (total light transmitted amount)
is 70% or more.

The lens portion of the intraocular lens of this invention completely absorbs ultraviolet rays and allows most of visible rays to pass through, indicating that it is substantially transparent when measuring the ultraviolet-visible light spectrum. The point where the rate becomes zero (the so-called cut-off point) is exactly the boundary point (380n) between the ultraviolet light region and the visible light region.
m), which can be confirmed by the fact that this cutoff occurs almost vertically.

C Example 1 The present invention will be specifically explained with reference to Examples.

Example 1 In a container equipped with a stirrer, a reflux condenser, and a nitrogen inlet tube, 36.8 g (0.1 mol) of 4,4'-bis(3-aminophenoxy)biphenyl and 202 g of N,N-dimethylacetamide were added. 3. Charge and incubate under nitrogen atmosphere at room temperature.
30.5 g (0,099 mol) of 3°, 4.4°-diphenyl ether tetracarboxylic dianhydride was added in portions while being careful not to increase the solution temperature, and the mixture was stirred at room temperature for about 20 hours. The logarithmic viscosity of the polyamic acid thus obtained was 1.7 dl/g.

A portion of the above polyamic acid solution was taken and cast onto a glass plate, then at 100°C and 200°C.

Each was heated at 300° C. for 1 hour to obtain a colorless and transparent polyimide film with a thickness of 50 μm. The tensile strength of this polyimide film was 1380 kg/am'', and the tensile elongation was 15%. (Both measurement methods were ASTM D
Based on -882. Same below. ) Also, the glass transition temperature of this polyimide film is 208℃ (TMA Needleman Corporation, hereinafter the same applies), and the temperature at 5% weight loss in air is 515℃.
℃ (measured by DTA-TG; the same applies hereinafter).

The above polyimide film was punched out using a punch with a diameter of 38 mm, and 20 sheets were stacked at a temperature of 300°C and a pressure of 1 ton/
cm”, heat-press molded for 30 minutes to a thickness of 1mm.
A polyimide disc-shaped molded body was produced. This molded product was a homogeneous polyimide molded product in which the films were completely fused and integrated.

The ultraviolet-visible light spectrum of the polyimide molded article thus obtained was measured to determine the wavelength of the cutoff point. Furthermore, the total light transmittance, specific gravity, and refractive index are determined.
The results are shown in the table. In addition, a pressure tester test was conducted at 121° C., 12 atmospheres, and 24 hours to examine changes in appearance, and the results are also shown in the same table.

Example 2 The polyamic acid solution obtained in Example 1 was placed in a Petri dish, placed in a vacuum dryer, and dried at a temperature of 25°C for 24 hours under reduced pressure.
40 hours at 00℃, 48 hours at 150℃, finally 25 hours
Heat treated at 0℃ for 24 hours to a thickness of 1. A polyimide molded body of 0 mm was produced. This molded article was a homogeneous and transparent polyimide molded article.

Regarding the polyimide molded article thus obtained, the wavelength at the cutoff point, total light transmittance, specific gravity, and refractive index were measured in the same manner as in Example 1 and are shown in Table 1. In addition, a pressure puller test was conducted in the same manner as in Example 1, and the results are also shown in the table.

Example 3 Polymerization was carried out in the same manner as in Example 1 except that 4.4°-bis(4-aminophenoxy)biphenyl was used instead of 4.4°-bis(3-aminophenoxy)biphenyl in Example 1. Ta. The logarithmic viscosity of the polyamic acid thus obtained was 1.35 dl/g.

A portion of this polyamic acid solution was taken and cast onto a glass plate at 100°C and 200°C.

Each was heated at 300° C. for 1 hour to obtain a colorless and transparent polyimide film with a thickness of 50 μm. The tensile strength of this polyimide film is 1250 kg/cm" and the tensile elongation rate is 22%.
Met. In addition, the glass transition temperature of this polyimide film is 243°C, and the temperature of 5% weight loss in air is 530°C.
Met.

Using the thus obtained polyimide film, a polyimide molded body having a thickness of 1 mm was produced in the same manner as in Example 1. In this molded product, the films were completely fused and integrated, resulting in a homogeneous polyimide molded product. Regarding this product, the wavelength at the cutoff point, total light transmittance, specific gravity, and refractive index were measured in the same manner as in Example 1, and are shown in Table 1. In addition, a pressure puller test was conducted in the same manner as in Example 1, and the results are also shown in the table.

Example 4 36.8 g (0.1 mol) of 4,4′-bis(3-aminophenoxy)biphenyl in Example 1 was mixed with 40 g (0.1 mol) of 4.4′-bis(3-aminophenoxy)diphenyl sulfide. ), except that 202 g of N,N-dimethylacetamide was replaced with 212 g.
Polycondensation was carried out in the same manner.

The logarithmic viscosity of the polyamic acid thus obtained was 1.1 dl.
/g.

254 g of N,N-dimethylacetamide was charged to 170 g of this polyamic acid solution, and 24.8 g (0.24 mol) of acetic anhydride and 9.05 g (0.09 mol) of acetic anhydride were added at room temperature under a nitrogen atmosphere while stirring. of triethylamine was added dropwise and stirred for 5 hours. Add this solution to 400 ml of water.
g, filter the precipitate, wash with methanol,
It was dried under reduced pressure at 50° C. for 8 hours to obtain 38.7 g of colorless powder. (Yield 96.4%) This powder was sandwiched between ferro plates having a 1 mm thick spacer coated with a mold release agent, and heated at 300°C.

Compression molding was performed at a pressure of 50 kg/cm'' to obtain a molded product with a thickness of 1 mm.The glass transition temperature of this molded product was 174°C.
The 5% weight dehumidification temperature in air was 523°C. Regarding this product, the wavelength at the cutoff point, total light transmittance, specific gravity, and refractive index were measured in the same manner as in Example 1, and the results are shown in Table 1. In addition, a pressure puller test was conducted in the same manner as in Example 1, and the results are also shown in the table.

Example 5 36.8 g (0.1 mol) of 4,4-bis(3-aminophenoxy)biphenyl in Example 1 was converted into bis[4
-(4-aminophenoxy)phenylkoketone 39.6
A polyamic acid solution having a logarithmic viscosity of 1.90 dl/g was obtained by carrying out the same procedure as in Example 1, except that g (0.1 mol) was used.

A colorless and transparent polyimide film with a thickness of 50 μm was obtained from the above polyamic acid solution in the same manner as in Example 1. The glass transition temperature of this polyimide film is 232℃
, 5% weight dehumidification temperature was 520''C.

Using the thus obtained polyimide film, a polyimide molded body having a thickness of 1 mm was produced in the same manner as in Example 1. In this molded product, the films are completely fused together.
It was a homogeneous polyimide molded product.

The cut-off wavelength, total light transmittance, specific gravity, and refractive index of the polyimide molded product thus obtained were measured, and the results are shown in Table 1.

In addition, a pressure puller test was conducted in the same manner as in Example 1, and the results are also shown in the same table.

[Effects of the Invention] As described above, the intraocular lens of the present invention has a lens portion made by reacting 3.3°, 4.4°-diphenyl ether tetracarboxylic dianhydride with a specific aromatic diamine. Made using the obtained colorless and transparent polyimide, 20
It can completely absorb ultraviolet rays in the 0-300 nm range, and transmit most of the visible light in the 380-780 nm range, providing substantial transparency. therefore,
When implanted in the eye, it absorbs and cuts harmful ultraviolet rays, protecting the retina and providing full vision. Moreover, the above-mentioned colorless and transparent polyimide is usually
It has a small specific gravity of 1.3 to 1.4 and a refractive index of 1.6.
~1.7, which is larger than conventional PMMA, so it is 30-50% thinner than PMMA products with the same diopter strength.
Therefore, it can be made lighter. Therefore, when implanted into the eye, the burden on the eye is light, and the possibility of contact with the cornea and complications is reduced, making it extremely safe.Moreover, the lens part of the intraocular lens of this invention is Since it is made using colorless and transparent polyimide, which has the same heat resistance as conventional aromatic polyimide, it can be easily sterilized using autoclave steam sterilization, and it can be melt-flowed and extruded and injection molded. is possible, and cost reduction can be achieved.

The intraocular lens of the present invention can be used as an anterior chamber supporting lens, a retrograde supporting lens, and in some cases, an iris supporting lens, and includes all of these.

[Brief explanation of the drawing]

1 and 2 show an example of the intraocular lens of the present invention, with FIG. 1 being a front view and FIG. 2 being a side view. ■...Lens part, 2...Hole, 3...Fixing part.

Claims (2)

[Claims] (1) Comprising a lens part and a fixing part for fixing the same in the eye, the lens part being composed of a colorless and transparent polyimide whose main component is a repeating unit represented by the following general formula (I). An intraocular lens characterized by: Formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, X is a direct bond, a divalent chain hydrocarbon group having 1 to 10 carbon atoms, a perfluoro(1-methylethylidene) group,
It represents a group selected from the group consisting of a carbonyl group and a thio group, and the bonding position of the nitrogen atom of the imide ring is meta or para to the ether bond. ) (2) The intraocular lens according to claim 1, wherein the lens part and the fixing part are integrated, and both are made of a colorless and transparent polyimide whose main component is a repeating unit represented by the above general formula (I). .