JPS63226359A - Intraocular lens - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

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 Hiro Soro. Intraocular lenses that make it possible to
(artificial crystalline lens).

[Conventional technology]

Methods for visual acuity recovery (forced refraction) for patients whose eyes have become aphakic after lens removal surgery due to cataract or the like include the use of spectacles, contact lenses, and intraocular lens implantation.

However, with spectacle correction, although visual acuity can be obtained after surgery, it may cause narrowing of the visual field (enlargement of the M4 membrane image) or Jack in the box (Jack in the box).

X) The patient is troubled by the phenomenon and has to endure it for a certain period of time before he or she can actually use it.

Moreover, especially in the case of a monocular aphakic eye, binocular vision cannot be obtained due to asymmetric vision. Wearing contact lenses is effective for such anisotropy, and high-water content soft contact lenses have now been developed, making it possible to wear them continuously and solving this problem. Because they are difficult to handle, even if they are prescribed after surgery, few people actually wear them.

[Problem that the invention seeks to solve]

Thus, correction using glasses and contact lenses cannot be said to be a preferable method. In contrast, artificial lens implantation is a method that has been used for 30 years.
Artificial crystalline lenses, so-called intraocular lenses, have less magnification of the retinal image, no visual field constriction or ring-shaped scotoma, and can provide binocular vision (this is especially superior to glasses for monocular aphakic eyes). ), it has many advantages because it does not require a period of getting used to it, and once it is transplanted, there is no need to handle it. In recent years, with the development of microscopes, ultrasonic scalpels, etc., transplant surgery techniques have improved, and the shape and material of intraocular lenses have improved.2. The above-mentioned intraocular lens will become the most important method for vision correction in aphakic eyes in the future.

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.

Incidentally, natural light includes wavelengths in the ultraviolet, visible, and infrared regions, and there is a risk that transmitting four amounts of ultraviolet light into the eye 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, the material for the above intraocular lens is 200 to 380 nm.
It is desired that the material absorb ultraviolet rays in the 1-range and be transparent to visible rays in the 380-780 nm range. Furthermore, if the intraocular lens itself is heavy, it puts a burden on the eye, so it is desired that the material used for the intraocular lens essentially has a low specific gravity and a high refractive index so that the lens thickness can be reduced.

Polymethyl methacrylate (PMMA) is currently most used as an intraocular lens. This PMM
A has excellent optical properties, is resistant to acids, alkalis, and organic solvents, and is resistant to changes over time.

However, the above PMMA has a glass transition temperature (TIi
) is low at 100°C or less and lacks thermal stability, so it cannot be sterilized in an autoclave using steam. That is, autoclave sterilization is usually performed at 121'C, 1,2
Because it is carried out at atmospheric pressure for about 1 hour, under these conditions P
This is because MMA softens and deforms, making it unusable. Therefore, intraocular lenses made of PMMA are sterilized using ethylene oxide gas, etc., but if gas remains inside the lens and enters the eye, there is a risk of inflammation of the mucous membranes. be. Therefore, in the gas sterilization method mentioned above, degassing is an essential step, which takes about two weeks, resulting in high costs and 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, attempts have been made to solve the above problem by adding an ultraviolet absorber, as seen in Japanese Patent Application Laid-Open No. 60-232149. 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. I can't say that. Furthermore, since PMMA has a smaller refractive index of about 1.4 than glass, the lens becomes thicker, and there is a possibility that the lens may adhere to the pupil, causing complications.

In this way, while PMMA has many advantages, it also has disadvantages.

Various materials are being considered that can be autoclaved, absorb ultraviolet light, and have a high refractive index. 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) Therefore, the lens itself becomes heavy and the burden on the eyes becomes large, which poses a problem in its use as an intraocular lens. sapphire, ruby, corundum, silicon,
Natural or synthetic crystals such as 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 still unsuitable for use as intraocular lenses. For this reason, interest in synthetic resins that can replace PMMA has recently increased, and polysulfone, polyarylate, polyetherimide, and the like are being considered. The above-mentioned polysulfone has a high refractive index, has ultraviolet absorption properties, and has a softening point of 175°C, and can be sterilized in an autoclave, but it has difficulties in processability, so it has not been put to practical use. I can't. Furthermore, polyarylate also has a high refractive index and ultraviolet absorbability, and can be sterilized in an autoclave, but like the above-mentioned polysulfone, it has problems in processability and is difficult to put into practical use. Also,
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, so it cannot be used in intraocular lenses. It is impossible to use it as such.

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.
The reality is that they are used as materials for intraocular lenses by adding ultraviolet absorbers that may have adverse optical and biological effects.

Therefore, it can be easily processed into a thin lens shape by machining or molding, and the specific gravity is 1.7.
below, preferably 1.5 or less, has a refractive index of 1.5 or more, preferably 1.6 or more, is chemically stable and biocompatible, and is dangerous to the retina. There is a strong need for the development of intraocular lens materials that absorb strong ultraviolet rays and have heat resistance that allows autoclave steam sterilization.

This invention was made in view of these circumstances, and has excellent biocompatibility, ultraviolet absorption, low specific gravity, high refractive index, chemical stability, and heat resistance that allows autoclave steam sterilization. The purpose is to provide an intraocular lens that is equipped with:

[Means for solving problems]

In order to achieve the above object, the intraocular lens of the present invention includes:
A lens comprising a lens part and a fixing part for fixing it in the eye, and the lens part is made of a colorless and transparent polyimide whose main component is a repeating unit represented by the following general formula (■). It is.

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 aromatic polyimide is colored yellow or brown, it absorbs not only ultraviolet rays but also a considerable portion of visible light. Therefore, the present inventors have conducted repeated research on the development of aromatic polyimides that do not absorb visible light, and have found that when aromatic polyimides represented by the above general formula (1) are used, they completely absorb ultraviolet rays and The result is an intraocular lens that is substantially transparent, transmitting most of the visible light, and, like conventional aromatic polyimides, has the properties required for intraocular lenses and is biocompatible. This invention was achieved by discovering that it is also excellent.

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
By a colorless and transparent polyimide [mainly consisting of a repeating unit represented by general formula (1)] that is substantially transparent to visible light in the ~780nmJT range and has heat resistance that can withstand autoclave sterilization. It is configured.

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 (1). Such a colorless and transparent polyimide is made of, for example, 3,3',4,4'-diphenylsulfone tetracarboxylic dianhydride represented by the following general formula (II) (hereinafter referred to as the blank) and -S formula ( It is obtained by reaction with an aromatic diamino compound represented by III).

112N-R-Nil, (III) Examples of the above-mentioned aromatic diamino compounds include the following.

nt N% O-@-NH2 3,3'-diaminodiphenyl ether part-10
゛11□ 3.31-diaminodiphenylsulfone HzN@-S-
■Nth 3.3゛ -diaminodiphenylthioether HzN-
@CIf z-Co NHz3.3" -Diamino diphenylmethane 3.3" -Diaminobenzophenone bis(4-(3-aminophenoxy)phenyl)sulfone 2.2-bis(4-(3-aminophenoxy)phenyl)propane 2 .2-Bis(4-(3-aminophenoxy)phenyl]hexafluoropropane If tNUNH□ m-phenylenediamine m-)lylenediamine (blank below) 4.6-dimethyl-m-phenylenediamine 2.4-diaminomesitylene 4-chloro-m-phenylenediamine 3.5-diaminobenzoic acid 5-nitro-m-phenylenediamine'-N@O■0愈NH 1,3-bis(3-aminophenoxy)benzene The above aromatic diamines are each It can be used alone or
They may be used in appropriate combinations.

By combining the above-mentioned 3.3'4.4'-diphenylsulfone tetracarboxylic dianhydride with the above-mentioned aromatic diamine having an amino group at the meta position, it is possible to obtain a compound represented by the general formula (1) for the first time. The result is a colorless and transparent polyimide whose main component is repeating units.

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 (1), which is the main component of the colorless and transparent polyimide, the more colorless and transparent the resulting polyimide becomes. However, the above general formula (1
) If the repeating unit represented by 80 mol % or more is contained, at least the ultraviolet absorbency and visible light transmittance required by this invention are ensured, so within that range,
Using other aromatic tetracarboxylic dianhydrides other than the above-mentioned 3,3"4.4"-diphenylsulfone tetracarboxylic dianhydride and other diamino compounds other than the above-mentioned aromatic diamine having an amino group at the meta position. be able to. However, the preferred range of the content of the repeating unit represented by the above general formula (1) 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 and 3.3'.

4.4゛-Biphenyltetracarboxylic dianhydride, 2
．． 3,3°, 4° -Biphenyltetracarboxylic dianhydride, 3,3'', 4.4'' -benzophenonetetracarboxylic dianhydride, 4,4゛-oxycyphthalic dianhydride, 4,4°- Bis(3,4-dicarboxyphenoxy)diphenylsulfone dianhydride, 2,2-bis(3
,4-dicarboxyphenyl)hexafluoropropane dimhydrate, 2゜3.6.7-naphthalenetetracarboxylic dianhydride, 1,2.5.6-naphthalenetetracarboxylic dianhydride, 1, Examples include 4,5.8-naphthalenetetracarboxylic dianhydride, which can be used alone or in combination.

Further, other diamino compounds include 4゜4゛-diaminodiphenyl ether, 3.4''-diaminodiphenyl ether, 4.4゛-diaminodiphenylsulfone, 4.4゛-diaminodiphenylmethane, 4.
4°-diaminobenzophenone, 4.4'-diaminodiphenylpropane, p-phenylenediamine, benzidine, 3.3'-dimethylbenzidine, 4. 4'
-Diaminodiphenylthioether, 3,3”-
Dimethoxy-4°4°-diaminodiphenylmethane, 3
．． Examples include 3”-dimethyl-4,4°-diaminodiphenylmethane, 2,2-bis(4-aminophenyl)propane, and 2,2-bis(4-(4-aminophenoxy)phenyl)-hexafluoropropane. , 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 under conditions of temperature: 50 to 350° C. and 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, such as by removing the solvent and imidizing the polyamic acid with a benzene solution of pyridine and acetic anhydride to form a 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, the solution after polyamic acid synthesis can be directly heated to 100° C. or higher to imidize it, and polyimide can be obtained as a precipitate from the solution. In this case, although filtration and washing are required, substantially the same colorless and transparent polyimide is obtained.

As the above organic polar solvent, amide organic polar solvents such as N,N-dimethylformamide and N,N-dimethylacetamide are suitable. Particularly preferred are those having a boiling point of 170° C. or lower, such as N,N-dimethylacetamide. These organic polar solvents may be used alone or in combination with
There is no problem in using a mixture of more than one species. However, it is preferable to avoid using N-methyl-2-pyrrolidone as the organic polar solvent. N-methyl-2-pyrrolidone is partially decomposed by heating the excipient of the polyamic acid solution and dehydrated and ring-closed to form polyimidation, and the decomposed product remains and becomes blackish brown. This is because the produced polyimide tends to be colored yellowish brown. As the organic polar solvent, N, N-
Each solvent such as dimethylacetamide has a low boiling point, so
Due to the above heating, the N-
Does not cause coloring on polyimides such as methyl-2-pyrrolidone.

However, N-methyl-2-pyrrolidone is used as a polymerization solvent, and after polyamic acid synthesis, the polyamic acid solution is poured into a poor solvent for polyamic acid, such as water, to reprecipitate the polyamic acid. The above-mentioned adverse effects of N-methyl-2-pyrrolidone can be eliminated if it is imidized in the presence of N-methyl-2-pyrrolidone, or if it is imidized after being redissolved in another preferred solvent.

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 type or a mixture of two or more types may be used as appropriate within a range that does not impair solubility. However, if these solvents are used in large amounts, they will adversely affect the solubility of the polyamic acid produced. Therefore, it is appropriate to limit the amount used to less than 50% by weight of the total 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 0.3 to
It is preferably in the range of 5.0.

More preferred is 0.4 to 2.0. The above intrinsic viscosity is 0.5 g/100 in N,N-dimethylacetamide.
This is the value measured at the concentration of If the intrinsic viscosity is too low, the resulting intraocular lens will have low mechanical strength, which is not preferable. Further, if the intrinsic viscosity is too high, it is not preferable because it becomes difficult to shape the polyamic acid solution into an appropriate shape or to isolate the polyamic acid. In addition, the concentration of the polyamic acid solution was also determined from the viewpoint of workability, etc.
It is preferable to set the amount to 30% by weight, preferably 15 to 25% by weight.

The above-mentioned intrinsic viscosity is calculated by the following formula, and the viscosity in the formula is measured using a capillary viscosity needle.

Examples of methods for producing an intraocular lens using the colorless and transparent polyimide obtained as described above include the following method.

The first method is to cast the polyamic acid solution onto a mirror-finished glass plate, stainless steel plate, etc. to a certain thickness, and gradually heat it at a temperature of 100 to 350°C to dehydrate and close the ring. A polyimide film is obtained by imidizing polyamic acid. In film formation from a polyamic acid solution, removal of the organic polar solvent and heating for imidization of the polyamic acid may be performed continuously, or 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, heat dry it at 100 to 150°C for 30 to 120 minutes to form a film, and mix this film with pyridine and anhydrous. This is a method in which the film is made into a polyimide film by immersing it in a benzene solution of acetic acid or the like to remove the solvent and perform an imidization reaction, 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 to 400℃, pressure 0.5 to 0.1 to Lot/cJ
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 to pour the polyamic acid solution into a poor solvent such as water or methanol, reprecipitate the polyamic acid, and then collect it.
By heating at a temperature of 100 to 350°C, dehydration and ring closure are performed to imidize, followed by pulverization to obtain anhydrous and transparent polyimide powder, and using this powdered polyimide, heating at a temperature of 200 to 400°C in the same manner as above. , pressure 0.5-10t
/cal for 0.1 to 10 hours to obtain a transparent polyimide molded body, which can be polished into an intraocular lens in the same manner as described above.

In the second method above, another method for obtaining a colorless and transparent polyimide powder is to convert the polyamic acid into polyimide by heating the polyamic acid solution to 100 to 200°C while stirring, and then convert the polyamic acid into polyimide as a precipitate. There is a method of precipitating it out of the system, and in this case, it is possible to use it for hot-press molding only by cleaning and drying.

In this way, when producing an intraocular lens using a colorless and transparent polyimide film or polyimide powder, the obtained intraocular lens has an intrinsic viscosity (0.5 g/d1 in 97% sulfuric acid) from the viewpoint of mechanical strength. The concentration (measured at 30° C.) is preferably set within the range of 0.3 to 4.0. The most preferred range is 0.4 to 2.0.

The third method does not use thermoforming like the first and second methods, but uses 1. This is a method to obtain a polyimide molded body directly from polyamic acid. Conventional drying methods cannot suppress foaming,
It is difficult to obtain a homogeneous polyimide molded body with a diameter of 150 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.

Intraocular lenses can be manufactured from polyimide molded bodies obtained by the three methods described above, 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 for implantation into a retrograde human eye) is shown in FIGS. 1 and 2. In the figure, ■ is a lens part, 2 is a position adjustment hole formed along the circumference at the peripheral edge of the lens part 1, and 3 is a fixing part for fixing the lens part 1 in the eye. be.

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 part, may be used.

Note that, 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 integrally formed. In this case, 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. When the lens portion of the intraocular lens of the present invention has a thickness of 0.5 mm, the total transmission amount of visible light (total light transmission amount) is 70% or more.

The reason why the lens part of the intraocular lens of this invention completely absorbs ultraviolet rays, transmits most of visible rays, and is substantially transparent is that when the ultraviolet-visible light spectrum is measured, the transmittance is The point where is zero (the so-called cut-off point) is exactly the boundary point (380n) between the ultraviolet light region and the visible light region.
m), and this is considered to be due to the fact that this cutoff occurs almost vertically. Among the colorless and transparent aromatic polyimides other than polyimide used in this invention, there are some with cutoffs around 380 nm, but these decrease in transmittance gradually from the higher wavelength side, and therefore,
The total light transmittance is extremely poor, and therefore, it cannot be applied to intraocular lens applications.

〔Effect of the invention〕

As described above, the intraocular lens of the present invention has a lens portion made using a colorless and transparent polyimide obtained by combining biphenyltetracarboxylic dianhydride and an aromatic diamine having an amino group at the meta position. Because there are
It can completely absorb ultraviolet rays in the 200-300 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, protects the retina, and provides sufficient visual acuity. Furthermore, the above-mentioned colorless and transparent polyimide usually has a small specific gravity of 1.3 to 1.4, and a refractive index of 6 to 1.7, which is larger than that of conventional PMMA. 3 to 5 P compared to those made of MMA
It can also be made thinner (thus 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, since the lens part of the intraocular lens of the present invention 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. It is possible to achieve cost reduction.

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.

Next, one example will be described together with a comparative example.

[Example 1] Using N,N-dimethylacetamide as a solvent,
1 mole of 3.3'-diaminodiphenylsulfone was reacted with 1 mole of 3.3',4.4''-diphenylsulfone tetracarboxylic dianhydride to obtain a polyamic acid solution. The concentration of the polymer was set to 20% by weight.This solution was cast onto a glass plate to form a film, and then heated in a hot air dryer for 120% by weight.
A polyimide film having a thickness of 50 μm was produced by imidizing the mixture by heating at 180° C. for 60 minutes, 250° C. for 3 hours, and 300° C. for 30 minutes. When the infrared absorption spectrum of the thus obtained polyimide film was measured, no absorption of amic acid was observed, but absorption peculiar to imide groups was observed at 1780c+++-'.

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/a.
! A polyimide disc-shaped molded body having a thickness of 1 fl was produced by hot-pressing molding under conditions of , 30 minutes. 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 were determined and the results are shown in Table 1 below.

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] A polyimide film was produced in the same manner as in Example 1 except that bis(4-(3-aminophenoxy)phenyl)sulfone was used in place of 3.3'-diaminodiphenylsulfone. In the infrared absorption spectrum of this film, there was no absorption of amic acid, but absorption of imide group was observed at 1780C11-'.

Using the polyimide film thus obtained, a polyimide molded body having a thickness of 1 fin 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 3] Instead of 3.3゛-diaminodiphenylsulfone, 3
．． 3"-diaminodiphenyl ether was used. A polyimide film was produced in the same manner as in Example 1 except for this. In the infrared absorption spectrum of this film, there was no absorption of amic acid, and absorption of imide group was observed at 178Qcna-'. It was done.

Using the polyimide film thus obtained, a polyimide molded body having a thickness of 111 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] Instead of 3.3゛-diaminodiphenylsulfone, ■
, using 3-bis(3-aminophenoxy)benzene,
N,N-dimethylformamide was used in place of N,N-dimethylacetamide. A polyimide film was produced in the same manner as in Example 1 except for the above. There is no absorption of amic acid in the infrared absorption spectrum of this film, and 178
Imide group absorption was observed at 0C[l-'.

Using the thus obtained polyimide film, a polyimide molded body having a thickness of 11 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.

[Comparative Example 1] Instead of 3.3゛-diaminodiphenylsulfone, 4
．． Using 4'-diaminodiphenyl ether, N,N
-N-methyl-2-pyrrolidone was used in place of dimethylacetamide. A polyimide film was produced in the same manner as in Example 1 except for the above. There is no absorption of amic acid in the infrared absorption spectrum of this film, and the infrared absorption spectrum is 1780 cm.
-' absorption of imide group was observed.

Using the thus obtained polyimide film, a polyimide molded body having a thickness of l++n was produced in the same manner as in Example 1. This molded product was highly colored and was completely fused and integrated, but it was impossible to determine what was happening. Regarding this, as in Example 1, the wavelength of the cutoff point,
The total light transmittance, specific gravity, and refractive index were measured and shown in Table 1.

[Example 5] The polyamic acid solution obtained in Example 1 was poured into water to reprecipitate the polyamic acid, and the solution was thoroughly stirred to remove the solvent, recovered, washed with methanol, and then dried under reduced pressure. The polyamic acid powder thus obtained was dried in a hot air dryer for 25 minutes.
It was heated to 0°C to imidize. Thereafter, it was crushed into a fine powder.

Using the polyimide powder obtained as described above, a polyimide molded body having a thickness of 1 fl was produced by hot-pressing molding at a temperature of 300° C., a pressure of 1 ton/cJ, and a time of 30 minutes. In this molded body, the powders were completely fused and integrated to form a homogeneous and transparent polyimide molded body.

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.

[Comparative Example 2] Using the polyamic acid solution obtained in Example 1, Example 5
Polyimide powder was prepared in the same manner as above.

Using the polyimide powder thus obtained, a polyimide molded body having a thickness of lyam was produced in the same manner as in Example 5. This compact was highly colored and the powders were not completely fused together.

Regarding the polyimide molded body thus obtained, the cutoff point wavelength, total light transmittance, specific gravity 2. The refractive index was measured and shown in Table 1.

[Example 6] The polyamic acid solution obtained in Example 2 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.Then, the solution was dried using infrared rays while maintaining the reduced pressure state. te1
40 hours at 00℃, 48 hours at 150℃, finally 25 hours
A polyimide molded body having a thickness of 0.8 fins was produced by heat treatment at 0° C. for 24 hours. This molded article was a homogeneous and transparent polyimide molded article.

Regarding the polyimide molded article obtained in this way,
As in Example 1, the wavelength of the cutoff point, the total light transmittance,
Specific gravity and refractive index were measured and shown in Table 1. In addition, Example 1
A pressure kick test was conducted in the same manner as above, and the results are also shown in the same table.

[Comparative Example 3] Using the polyamic acid solution obtained in Comparative Example 1, a polyimide powder having a thickness of 0.8 mm was produced in the same manner as in Example 6. Although this molded product was homogeneous, it was a highly colored polyimide molded product.

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.

(Hereinafter in the margin) Table 1 (hereinafter in the margin) [Example 7] Using the polyimide molded product obtained in Example 6, an intraocular lens for rabbit eyes was produced. The intraocular lens thus obtained was implanted into the anterior chamber of a rabbit's eye and its effects were investigated for six months. As a result, no toxic or harmful effects were observed. When the lens was taken out again and its optical properties were measured, it was found to be exactly the same as before implantation.

[Brief explanation of the drawing]

FIG. 1 is a plan view of an intraocular lens for retrograde implantation in a human eye, and FIG. 2 is a side view of FIG. 1. l...Lens part 2...Position adjustment hole 3...
・Fixed part patent applicant: Nitto Electric Industry Co., Ltd. Figure 1 Figure 2

Claims (2)

[Claims] (1) Comprising a lens part and a fixing part for fixing this in the eye, the lens part being made of colorless and transparent polyimide whose main component is a repeating unit represented by the following general formula (I). An intraocular lens comprising: ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [In formula (I), R is ▲There are mathematical formulas, chemical formulas, tables, etc.▼[However, X_1 is O, S, SO_2, CH_2, CF_2,
C(CH_3)_2, C(CF_3)_2 or CO], ▲There are mathematical formulas, chemical formulas, tables, etc.▼[However, X_2 is SO_2, C(CH_3)_2 or C(CF
_3)_2], ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [However, X_3 to X_6 are H, F, Cl, CH_3,
C_2H_5, NO_2, COOH or CF_3, which may be the same or different]
Or ▲There are mathematical formulas, chemical formulas, tables, etc.▼. ] (2) Claim 1, in which the lens part and the solid part are integrated, and both are made of colorless and transparent polyimide mainly composed of repeating units represented by the above general formula (I).
Intraocular lenses as described in section.