JPH0544331B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a mold used in cast polymerization, which is a method for producing lenses, and more specifically, to a mold used in the production of hard contact lenses or soft contact lenses by cast polymerization. The present invention relates to a suitable soft contact lens mold. [Prior Art] Conventionally, contact lenses have been mainly manufactured by subjecting a polymeric composition having desired physical properties to mechanical processing such as cutting and polishing (hereinafter referred to as the cutting and polishing method). A contact lens with good optical performance can be obtained, and its shape can be designed relatively freely as required. In addition, as another method for manufacturing contact lenses,
There is a method called a spin cast method in which a polymer solution is solidified on a rotating mold to obtain a contact lens. The spin-casting method involves carefully controlling a number of factors such as the viscosity of the polymerization solution, surface tension, amount used, shape of the mold, rotational speed, surface condition, etc. to form the desired contact lens. It is expected to improve productivity compared to , and is advantageous for manufacturing thin contact lenses. Furthermore, as another method for manufacturing contact lenses, the cast polymerization method is a manufacturing method in which a polymer solution is polymerized and solidified in a mold with a predetermined optical surface to form a contact lens shape, and is highly productive and easy to implement. It has the advantage of being easy to use. [Problems to be solved by the invention] However, as is well known, the cutting and polishing method is a method in which each lens is cut out from a material one by one and finished by polishing, so it inevitably requires a large number of manufacturing steps. However, it had problems such as poor productivity. Furthermore, the cutting and polishing method requires advanced machining techniques and has the disadvantage of requiring a large number of skilled workers. Furthermore, in the cutting and polishing method, the first condition is that the material is hard and can be machined, so even if the material has excellent physical properties, if there are problems with machinability or polishability, It had the disadvantage that it could not be made into contact lenses. In particular, many soft contact lens materials with a high water content are soft, which causes problems with machinability and polishability, and lens materials have strong hygroscopic properties, so they are susceptible to the effects of moisture in the air during processing. The problem was that it was easy to use, and that it was necessary to maintain a low humidity environment at all times. Furthermore, high water content soft contact lenses produced by cutting and polishing have a disadvantage in that dirt from tear fluid tends to adhere to them due to poor surface smoothness. On the other hand, the spin-casting method requires highly sophisticated technology as it requires strict control of a large number of factors as described above, and furthermore, the materials to which it can be applied are limited to specific materials. In addition, the concave surface of a contact lens obtained by the spin cast method is an almost parabolic aspheric surface, making it impossible to obtain a true optical surface. It has the disadvantage that it is difficult to set. Additionally, lenses obtained by spin-casting typically have the disadvantage of requiring final finishing around the lens after polymerization. The cast polymerization method is effective as a means to solve the above-mentioned problems in the cutting and polishing method and the spin-casting method. However, the cast polymerization method involves the problem of volume shrinkage called polymerization shrinkage that occurs when a polymerizable liquid is polymerized and solidified. The volume shrinkage due to polymerization shrinkage of many monomers is in the range of 12% to 22%, and this shrinkage is in the range of 12% to 22%. This has been a major hindrance to the cast polymerization of contact lenses from vinyl monomers such as amides. In other words, when a contact lens is cast in a sealed mold, voids called sink marks may occur on the surface of the lens due to polymerization shrinkage, or cavities called voids may occur inside the lens, causing the cast product to become a contact lens. Makes it unsuitable as a lens. In order to solve these problems of cast polymerization, various methods have been taught so far. For example, according to the method disclosed in Japanese Patent Application Laid-Open No. 52-117647, a flexible rim part is integrally placed in one of a set of molds, and polymerization shrinkage is caused by the curvature of the flexible rim part and the resulting thickness. Absorb by decreasing thickness. However, although it is possible to absorb the polymerization shrinkage when the polymerization composition liquid is polymerized and solidified by this method, there is no control mechanism for the thickness of the resulting lens, so the thickness of the lens to be molded is There is a problem with molding accuracy that variations in thickness occur. In addition, since the above flexible rim parts directly form the outer periphery of the contact lens during cast polymerization, the design around the lens is limited to the shape created by the curvature of the rim, making it impossible to design freely. It had the following drawbacks. Furthermore, since the flexible rim part must be integrated with the mold, the materials that can be used as the mold are inevitably limited to flexible materials such as plastic due to processing or material selection. The drawback is that there is little freedom in the selection of materials for molds, and there are inevitably limits to the hardness and heat resistance of materials required for molds. The problem was that deformation easily occurred and sufficient optical precision could not be obtained. Furthermore, in order for the flexible rim to have sufficient curvature to absorb polymerization shrinkage, its thickness must be extremely thin, and its tip must be 0.04 m/
Since it has to be sharpened to a depth of 0.01 m/m to 0.01 m/m, it poses a handling problem in that it can be easily damaged even by slight contact. Further, for example, according to the method disclosed in Japanese Patent Application Laid-Open No. 54-43268, a soft contact lens in a swollen state can be manufactured by polymerizing and solidifying a polymerizable liquid together with a solvent in a mold. However, since this method is an abbreviation of the polymerization method using a solvent (solution polymerization method) for the production of soft contact lenses, lenses formed by polymerization are always limited to those containing a solvent. In addition, since the above-mentioned mold does not have any mechanism for absorbing polymerization shrinkage, it naturally has the disadvantage of not being able to mold non-hydrous hard contact lenses. The present invention was made for the purpose of solving the problems in the method for manufacturing contact lenses as described above, and more specifically, it solves the problems in the method for manufacturing contact lenses by cast polymerization, and provides a method for producing contact lenses of excellent quality. The purpose was to manufacture soft contact lenses extremely easily and in a short period of time. [Means for Solving the Problems] In order to achieve the above object, the present invention interposes a ring-shaped spacer between a male molding member and a female molding member on the outer periphery of the molding part of both molding members. With,
In order to control the lens thickness when the mold is closed, the lens mold is made by forming a sharp portion on the opposing surfaces of the molding part outer periphery of both molding members. Hereinafter, the configuration of the present invention will be explained in detail with reference to the drawings. FIG. 1 is a partially cutaway exploded perspective view illustrating the structure of the present invention, and FIG. 2 is a cutaway front view showing an assembled state of the molds shown in FIG. 1. The present invention comprises a female molding part 4 having a main axis for assembly in the vertical direction and having a first molding part 2 containing a first optical molding surface 1 for forming the first surface of the lens; has a common main axis with the molded member 4 of
Female molding member 8 having a second molding portion 6 containing a second optical molding surface 5 for forming the second surface of the lens: a ring-shaped molding member having an axis common to the main axes of the molding members 4, 8 described above; It is composed of a spacer 9: a mounting portion 10 for controlling the thickness of the lens, and a liquid reservoir 3 provided in a slope shape around the insertion portion of the female molded member 8. This liquid reservoir 3 can store excess polymer composition liquid, so even if the amount of polymer composition liquid is not poured into the mold accurately, the polymer composition liquid may come into contact with the spacer and adhere to it or attack the spacer. There is nothing to do. As the material of the male molding member 4, the female molding member 8, and the cutout portion 10 presented in the present invention, materials commonly used as mold materials such as glass, metal, ceramic, and plastic can be used. Particularly when selecting thermoplastic plastic as a mold material, it is important to select a material with a heat deformation temperature 20 to 40°C higher than the polymerization temperature. Alternatively, by applying a normal plastic molding method such as a compression molding method, it has the advantage that a molded member with high precision can be manufactured with extremely high productivity. Examples of such thermoplastics include high density polyethylene, polypropylene, polytetrafluoroethylene, polychlorotrifluoroethylene, polyolefin copolymers, polyacetals, polyphenylene oxides, polysulfones, polyamides, and the like. Further, as the material for the spacer proposed in the present invention, thermoplastic plastics or rubber elastic bodies having good flexibility near the polymerization temperature can be used. Examples of such materials include low density polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, soft vinyl chloride, ionomer resin, urethane rubber, natural rubber, isoprene rubber, butadiene rubber, styrene- Examples include butadiene rubber, chloroprene rubber, nitrile rubber, silicone rubber, and acrylic rubber. These materials are
It is used after being molded into a predetermined shape using a normal molding method. In the specific example of the present invention shown in FIGS. 1 and 2, the base portion 10 is formed integrally with the second molded member 8, but it may also be formed integrally with the first molded member 4. . Further, the attachment portion is not limited to being integrated with the molded member, and may be placed separately inside or outside the spacer. The following description will be made based on a case where the Tsukiate portion 10 is integrally formed with the first or second molded member. [Function] In the lens mold according to the present invention, the male molding member 4 and the female molding member 8 are assembled along the main axis with a spacer 9 interposed between them. The molding part 2 and the second molding part 6 of the female molding member 8 form a vertically movable fitting structure, creating a gap for contact lens molding that is shielded from the outside. When the molded members 4 and 8 are in complete contact with each other via the spacer 9, this gap provides a capacity corresponding to the predetermined shape of the contact lens. The amount of the polymerized composition liquid that will be polymerized and solidified to form a contact lens is slightly larger to account for the volume of the contact lens to be molded into the second molding section 6 of the female molding member 8, as well as the amount of polymerization shrinkage and overflow. It is dripped with Thereafter, the spacer 9 is placed on the spacer contact portion of the second molded member, and the male molded member 4 is placed on the female molded member 8 along the main axis and moved downward. At this time, the excess polymeric composition liquid is gradually removed from the molding space as the male molding member 4 moves, and when both molding members 4 and 8 come into complete contact via the spacer 9, a certain volume of the polymeric composition liquid is removed. fills the void for contact lens molding. The liquid reservoir 3 can store excess polymerizable liquid, so even if the amount of polymerizable liquid is not poured into the mold accurately, the polymerizable liquid will not come into contact with the spacer and cause it to adhere or attack the spacer. There's nothing to do. The void for contact lens molding filled with the polymeric composition liquid is formed in the first molding section 2 as described above.
and the second molding section 6, so that the polymerization liquid does not come into contact with air. By placing the mold filled with the polymerization composition liquid in this manner in a thermostatic oven and heating it according to a predetermined temperature increase program, a desired contact lens can finally be molded. When the polymerization composition liquid starts polymerizing in the heating process, its volume decreases due to polymerization contraction, and during this process, the polymerization composition liquid spreads onto the first optical molding surface 1 and the second optical molding surface 5. As a result, a force is exerted in a direction that causes both optical molding surfaces to approach each other. The spacer 9 according to the present invention exhibits sufficient flexibility during the polymerization process, thereby reducing its thickness as the molded members 4 and 8 approach each other, and absorbing polymerization shrinkage in the thickness direction of the lens. On the other hand, the thickness portion 10 formed on the second molded member 8 is preliminarily designed to have a gap between it and the first molded member 4 corresponding to the amount of decrease in wall thickness that occurs when the polymerization composition liquid completes polymerization. is set,
To accurately determine the thickness of a lens to be molded and to prevent the thickness of the lens to be molded from being partially uneven. That is, if a partial non-uniformity of polymerization shrinkage occurs, such as a part of the polymer composition liquid shrinking faster than other parts, the first optical molding surface 1 of the first molding member 4 will be different from that of the second molding member 8. It is tilted relative to the second optical molding surface 5, giving the lens to be molded an uneven thickness, but as polymerization shrinkage progresses, the first molded member is located in the portion where the shrinkage occurs first. 4 is restricted from further shrinking by contacting the strength part 10, and the subsequent polymerization shrinkage proceeds in other parts where the strength part 10 is not yet in contact with the first molded member 4. . Therefore, the Tsukiate part 10 corrects the relative inclination of the first optical molding surface 1 to the second optical molding surface 5 until the polymerization shrinkage is completed, and accurately adjusts the center thickness of the lens to be molded. and prevent local unevenness in wall thickness. In the present invention, a load can be applied to the assembled molds. The load applied to the mold actively encourages the two molded parts to approach each other during polymerization shrinkage, making it easier to prevent sink marks, and also providing more favorable results in controlling the wall thickness using the cutout part. . The above-mentioned polymer composition liquid is made by adding appropriate amounts of a polyfunctional crosslinking agent and a polymerization initiator to a monomer or prepolymer having a single composition or a multicomponent composition. The monomers used here include the following. (a) Methyl methacrylate, ethyl methacrylate,
n-butyl methacrylate, iso- methacrylate
Hydrophobic methacrylic acid substituted monomers such as butyl, tert.-butyl methacrylate, n-propyl methacrylate, iso-propyl methacrylate, lauryl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, methylbenzyl methacrylate, isobornyl methacrylate. (b) Methyl acrylate, ethyl acrylate, n-butyl acrylate, iso-butyl acrylate,
Hydrophobic acrylic acid substituted monomers such as tert.-butyl acrylate, n-propyl acrylate, iso-propyl acrylate, cyclohexyl acrylate, benzyl acrylate. (c) Methacrylic acid-substituted monomers containing silicon, such as trimethylsilyl methacrylate, trimethylsilyl methyl methacrylate, and tris-trimethylsiloxylyl-propyl methacrylate. (d) Acrylic acid-substituted monomers containing silicon, such as trimethylsilyl acrylate, trimethylsilylmethyl acrylate, and tris-trimethylsiloxysilyl-probyl acrylate. (e) 2-hydroxyethyl methacrylate, 2-
Hydrophilic methacrylic acid substituted monomers such as hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, glyceryl methacrylate, glycidyl methacrylate, methacrylic acid. (F) Hydrophilic acrylic acid-substituted monomers such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, glyceryl acrylate, glycidyl acrylate, and acrylic acid. (g) N such as N-methylacrylamide, N,N-dimethylacrylamide, N-methylmethacrylamide, N,N-dimethylmethacrylamide, etc.
- Hydrophilic monomers such as alkyl-substituted acrylamides or N-alkyl-substituted methacrylamides. (h) Alkyl-substituted N-vinylpyrrolidone such as N-vinylpyrrolidone and methyl-substituted N-vinylpyrrolidone. In addition, examples of polyfunctional crosslinking agents include ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, vinyl methacrylate, allyl methacrylate, and triallyl isocyanate. Nurate, vinyl acrylate, divinylbenzene, etc., and further, azobisisobutyronitrile, azobisdimethylvaleronitrile, benzoyl peroxide, di-tert.-butyl peroxide, lauroyl peroxide, etc. are used as polymerization initiators. Ru. In addition, when the monomer selected from the above groups (a) to (d) is the main component and the monomer selected from the groups (e) to (h) is the subcomponent, it becomes a hard contact lens composition, In the opposite case, a soft contact lens composition is obtained. In the embodiment shown in Figures 1 and 2 of the mold according to the invention, the first optical molding surface 1 is substantially convex and the first The second optical shaping surface 5 needs to be substantially concave, but when the first optical shaping surface 11 is substantially concave, as in the other embodiment shown in FIG. It is also within the scope of the invention that optical shaping surface 15 is substantially convex. Furthermore, although the first optical molding surface 1 and the second optical molding surface 5 of the male and female molding members 4 and 8 according to the present invention can be sufficiently adapted to a contact lens designed by a combination of spherical surfaces, one of the male and female molding members 4 and 8 may be used as needed. Alternatively, the present invention is not limited in any way to a design in which both surfaces are made of aspherical surfaces. [Examples] Hereinafter, the present invention will be explained in more detail based on Examples. Embodiment 1 FIG. 1 is a partially cutaway exploded perspective view showing an embodiment of the present invention, and FIG. 2 is a cutaway front view of the embodiment shown in FIG. In this embodiment, the male molded member 4 and the female molded member 8 having the cutout portion 10 are manufactured by injection compression molding polypropylene. The spacer 9 is manufactured by injection molding an ethylene-ethyl acrylate copolymer. The first molding part 2 of the male molding member 4 has a cylindrical shape with a diameter of 8.5 mm and has a first optical molding surface 1 with a radius of curvature of 8.00±0.005 mm at the tip. The second molded part 6 of the female molded member 8 has a radius of curvature of 8.47±
A liquid reservoir 3 having a cylindrical shape with an inner diameter of 8.5 mm and having a second optical molding surface 5 of 0.005 mm at the bottom to prevent excess polymer composition liquid from coming into contact with the spacer 9.
have. Also, spacer 9 is 3.00±
It has a flat ring shape with a uniform wall thickness of 0.005mm. In this example, methyl methacrylate 100
Parts by weight, 1 part ethylene glycol dimethacrylate
0.2 ml of a polymer composition liquid consisting of 0.2 parts by weight of azobisisobutyronitrile is dropped onto the second molded part 6 of the female molded member 8, and a spacer 9 is installed on the spacer installation surface 7 of the female molded member 8. Then, the male molded member 4 was assembled along the main axis. At this time, the gap between the male molded member 4 and the contact member 10 was 0.02 mm. A load of 500 grams was placed on the top of the mold thus prepared, and the mold was placed in a thermostat with hot air circulation, and heated at 50°C for 12 hours and at 90°C for 6 hours. After heating, the mold is cooled to room temperature and then disassembled.
I took out the molded contact lens. There were no voids or voids on the surface or inside of the contact lens obtained, and no burrs were generated around the lens. The base curve of this lens is 8.00±
0.01mm, and the radius of curvature of the front curve is 8.47
It was ±0.01mm. Also, the size of this lens is
8.5mm, center wall thickness is 0.155mm to 0.165mm,
The edge thickness was 0.195mm to 0.205mm. When the refractive power of the molded contact lens was measured using a lens meter, it had a refractive power of -3.00±0.03 diopters, and the observed corona was also good. Embodiment 2 FIG. 3 is a longitudinal sectional front view showing a second embodiment of the present invention. The male molded member 14 and the female molded member 18 are manufactured by machining stainless steel, and the cutout portion 20 is integrally formed with the male molded member 14. Further, the spacer 19 is made by injection molding low density polyethylene. The first molded part 12 of this embodiment has a radius of curvature of 7.60±
First optical molding surface 11 made of a 0.005 mm concave spherical surface
The second molding part 16 has a cylindrical shape with an inner diameter of 8.8mm and has a second optical molding surface 15 which is a convex spherical surface with a radius of curvature of 7.80±0.005mm. It has a liquid reservoir 13 for holding the polymer composition. Also, spacer 19
It has a flat ring shape with a uniform wall thickness of 5.00±0.005mm. The polymer composition solution used in this example was trisutrimethylsiloxanylsilylpropyl methacrylate.
40 parts by weight, 60 parts by weight of ethyl methacrylate, 2 parts by weight of triethylene glycol dimethacrylate,
Consists of a mixed solution of 0.5 parts by weight of azobisdimethylvaleronitrile. A polymer composition solution was injected and a mold was assembled in the same manner as in Example 1. The gap between the female molded part 18 and the Tsukiate member 20 is 0.025 mm to 0.035 mm.
It was hot. The mold thus prepared was heated in a constant temperature bath for 8 hours at 40°C, 4 hours at 60°C, and 5 hours at 80°C for polymerization, then cooled to room temperature, the mold was disassembled, and the mold was molded. I took out the contact lenses. The molded contact lens had no external defects such as sink marks or burrs, and had a base curve radius of curvature of 7.80 ± 0.01 mm, a front curve with a curvature radius of 7.60 ± 0.01 mm, and a size of 8.8 mm. . The center wall thickness of this lens was 0.200mm to 0.205mm, and the edge thickness deviation was within 0.01mm at most.
The refractive power of this lens was +2.00±0.03 diopters. Embodiment 3 FIG. 4 is a longitudinal sectional front view showing a third embodiment of the present invention. The male molding member 24 and the female molding member 28 of this embodiment are manufactured by injection molding polychlorotrifluoroethylene, and the lugs 30 are integrally formed with the female molding member 28. The spacer 29 is made by injection molding an ionomer resin obtained by crosslinking an ethylene-acrylic acid copolymer with metal ions. The first molded portion 21 of the male molded member 22 has a radius of curvature.
The second molded part 26 of the female molded member 28 has a curvature radius of 6.32±.
It has a cylindrical shape with an inner diameter of 10.0 mm and a second optical molding surface 25 made of a concave spherical surface of 0.01 mm.
have. Also, the spacer is 1.995mm thick
No, it has a 2.005mm O-ring shape. 88 parts by weight of 2-hydroxyethyl methacrylate,
10 parts by weight of methyl methacrylate, 1 part by weight of ethylene glycol dimethacrylate, methacrylic acid
Injection was carried out in the same manner as in Example 1 using a polymer composition liquid consisting of 1.5 parts by weight of azobisisobutyronitrile and 0.2 parts by weight of azobisisobutyronitrile. The gap between the molding member 30 and the male molding member 24 created when the molds were assembled was 0.02 mm. A load of 700 grams was placed on the top of the combined molded hardwood, and the temperature was kept at 40℃ for 10 hours and at 60℃ for 4 hours in a constant temperature bath.
After heating at 80° C. for 4 hours, the mold was disassembled and the molded contact lens was taken out. The molded lens has no sink marks or burrs, and has a base curve with a radius of curvature of 5.93 ± 0.01 mm and a radius of curvature of 6.32.
It has a front curve of ±0.01mm, a size of 10.0mm, and its center wall thickness is 0.125mm to 0.135mm.
It was hot. Additionally, the edge thickness of this lens had a maximum unevenness of 0.01mm. Next, the obtained dry lens was immersed in physiological saline and saturated and swelled to form a soft contact lens. This soft contact lens had a base curve radius of 8.0 mm and a size of 13.5±0.03 mm, and had a stable shape without deformation or clouding. The center thickness of this lens was 0.19±0.01 mm, the edge thickness was 0.32±0.01 mm, and its refractive power was -3.00±0.08 diopters. The water content of this lens was 40±0.3%. Comparative Example 1 FIG. 5 is a longitudinal sectional front view showing a comparative example. The male molded member 34 and the female molded member 38 of this comparative example were manufactured by injection molding polypropylene, and the spacer 39 was manufactured by injection molding ethylene-ethyl acrylate copolymer. This mold does not have a mounting member for controlling wall thickness. First molded portion 32 of male molded member 34
is the first optical forming surface 3 with a radius of curvature of 8.00±0.01 mm.
It has a cylindrical shape with a diameter of 8.5 mm and has a number 1 at the tip.
The second molded portion 36 of the female molded member 38 has a radius of curvature.
It has a cylindrical shape with an inner diameter of 8.5 mm and a second optical molding surface 35 of 8.47±0.01 mm at the bottom. Further, the spacer 39 has a flat ring shape with a uniform wall thickness of 3.00±0.005 mm. Note that 35 is a second optical molding surface, and 36 is a second molding part. Put 0.2ml of the polymerization composition solution used in Example 1 into the mold.
After pouring and assembling the molds, heating was performed in a constant temperature bath in the same manner as in Example 1. When the mold was cooled to room temperature and then disassembled, and the molded contact lens was taken out, no sink marks were found on the surface or periphery of the lens. This lens has a base curve
8.00±0.02mm, front curve 8.47±0.02mm, center wall thickness 0.16±0.02mm, edge thickness is maximum
The thickness was uneven by 0.05 mm, and the variation in the thickness direction was large. Also, the refractive power of this lens is -3.00±
It was 0.05 diopters. Comparative Example 2 FIG. 6 is a longitudinal sectional front view showing another comparative example.
The male molded member 44 and the female molded member 48 are made of ethylene-vinyl acetate co-assembly, and the male molded member 4
The first molded portion 42 of No. 4 has a first optical surface 41 around which an annular thin rim 50 is integrally formed. This thin rim 50 bends toward the center of the lens when the polymer composition exhibits volumetric shrinkage during polymerization, reducing its height and absorbing the polymerization shrinkage. In FIG. 6, 45 is a second optical molding surface, and 46 is a second molding part. The outer diameter of the male molded member 44 is 7.9 mm, and the radius of curvature is
It has a first optical surface 41 of 7.45±0.03 mm, an inner diameter of the female molded member 48 is 8.2 to 8.4 mm, and a second optical surface 41 has a diameter of 7.45±0.03 mm.
Optical surface 45 has a radius of curvature of 8.55±0.05 mm. 98 parts by weight of methyl methacrylate, 20 parts by weight of ethylene glycol dimethacrylate, 0.3 parts by weight of di-t-butylcyclohexyl peroxydicarbonate
Pour 0.3 ml of the polymer composition liquid consisting of parts by weight into the female molding member, combine the molds, and place in a constant temperature bath at 60℃.
After heating for 1.5 hours, cool and disassemble the mold. The obtained contact lens has no sink marks or burrs, but the radius of curvature of its base curve is 7.47.
±0.4mm, and the center wall thickness was 0.10±0.02mm, making it impossible to obtain good accuracy. Further, the measurement results of the refractive power of this lens showed a significant variation of -7.50 to -8.50 diopters, which caused a practical problem. Note that a digital contact gauge manufactured by MEIZ Co., Ltd. and a laser interferometer manufactured by Fuji Photo Equipment Co., Ltd. were used to measure the radius of curvature. Further, a digital height gauge manufactured by Techrock and an optical microscope manufactured by Olympus were used to measure the center wall thickness of the lens, and a projector manufactured by Nikon Corporation was used to measure the diameter of the lens. Example 4 In this example, a male molding member 4, a female molding member 8, and polypropylene were produced by injection molding, and were combined as shown in FIG. 1 to form a mold. The spacer 9 was manufactured by injection molding an ethylene-ethyl acrylate copolymer. The first molded part 2 of the male molded member has a radius of curvature
It has a cylindrical shape with a diameter of 8.5 mm and has a first optical molding surface 1 of 5.03±0.005 mm at the tip. The second molding part 6 of the female molding member 8 has a cylindrical shape with an inner diameter of 8.5 mm and has a second optical molding surface 5 with a radius of curvature of 5.80±0.005 mm at the bottom. Moreover, the spacer 9 is
It has a flat ring shape with a uniform wall thickness of 3.00±0.005mm. 52 parts by weight of N,N-dimethylacrylamide,
10 parts by weight of N,N-dimethylmethacrylamide, 4 parts by weight of acrylic acid, 34 parts by weight of cyclohexyl methacrylate, ethylene glycol methacrylate
0.2 ml of a polymerizable liquid consisting of 0.2 parts by weight and 0.1 parts by weight of azobisisobutyronitrile is dropped onto the second molded part 6 of the female molded member 8, and a spacer is placed on the spacer installation surface 7 of the female molded member 8. 9 was installed, and the male molded member 4 was assembled along the main axis. The gap between the male molded member and the Tsukiate part 10 that occurs at this time is
It was 0.02mm. A load of 500 grams was placed on top of the mold thus prepared, as in the first example, and the mold was placed in a hot air circulation type constant temperature bath, and maintained at 40°C for 10 hours and at 80°C for 6 hours. After cooling the mold to room temperature, the lens was removed. Next, the obtained dry lens was immersed in physiological saline and saturated and swelled to form a soft contact lens. This soft contact lens has a base curve radius of 8.1mm, a diameter of 13.6mm, and a center wall thickness of 0.18±.
0.01mm, refractive index -5.50±0.06 diopters, water content 80%, tensile strength 43Kg/cm ² , light transmittance 99% in raw food, and is free from shape defects such as lens deformation, burrs, and sink marks. I couldn't see it. Moreover, the surface of the lens was extremely smooth. Example 5 In this example, the male molded member 4 shown in FIG. 1 and the female molded member 8 on which the cutout portion 10 is integrally formed are made by injection molding of ethylene-vinyl alcohol copolymer. It was created using
The same spacer 9 as in Example 4 was used.
The first molded part 2 of the male molded member 4 has a radius of curvature of 5.52
It has a cylindrical shape with a diameter of 8.8 mm and has a first optical molding surface 1 of ±0.005 mm at the tip. Female molded member 8
The second molded part 6 has a radius of curvature of 5.43±0.005mm.
It has a cylindrical shape with an inner diameter of 8.8 mm and has an optical molding surface 5 at the bottom, and has a liquid reservoir 3 for holding excess polymerizable liquid so that it does not come into contact with the spacer 9. In the above mold, 60 parts by weight of N,N dimethylacrylamide, 40 parts by weight of benzyl methacrylate,
A polymerizable liquid consisting of 10 parts by weight of acrylic acid and 0.07 parts by weight of azobisdimethylvaleronitrile was injected in the same manner as in Example 1. Place a load of 700 grams on the top of the combined mold,
After heating at 40°C for 10 hours, at 60°C for 4 hours, and at 90°C for 4 hours in a constant temperature bath, the molded lens was removed from the mold. The obtained dry lens was immersed in physiological saline and saturated and swelled to obtain a contact lens. This contact lens has a base curve radius of 8.6mm, a diameter of 13.6mm, and a center thickness of 0.20±0.01mm.
It has a refractive index of +1.50±0.06 diopters, a water content of 74%, a tensile strength of 38Kg/cm ² , and a light transmittance of 98%.It has excellent performance and is free from lens deformation, burrs, sink marks, and other shape defects. Nakatsuta. Example 6 FIG. 4 is a cutaway front view showing another mold provided by the present invention. Male molded member 2 of this example
4 and the female molded member 28 are made by injection molding polychlorotrifluoroethylene, and the molded member 30 is integrally formed with the female molded member. The spacer 29 is made by injection molding an ionomer resin obtained by crosslinking an ethylene-acrylic acid copolymer with metal ions. The first molded portion 22 of the male molded member 24 has a radius of curvature.
The female forming member 28 has a cylindrical shape with a diameter of 8.7 mm and has a first optical forming surface 21 of 5.25±0.01 mm.
The second molded part 26 has a radius of curvature of 5.64±0.01 mm.
It has a cylindrical shape with a diameter of 8.7 mm and has an optical molding surface 25 and a liquid reservoir 23. Further, the spacer 29 has an O-ring shape with a thickness of 1.995 mm to 2.005 mm. In the above mold, 75 parts by weight of N-vinylpyrrolidone, 25 parts by weight of benzyl methacrylate, 0.3 parts by weight of tetraethylene glycol dimethacrylate,
Injection was performed in the same manner as in Example 4 using a polymerizable liquid containing 0.1 part by weight of azobisisobutyronitrile. Place a load of 500 grams on the top of the combined mold,
After heating in a constant temperature bath at 60°C for 10 hours, 80°C for 4 hours, and 90°C for 3 hours, the lens was removed from the mold. Next, the obtained dry lens was immersed in physiological saline and saturated and swelled to form a soft contact lens. This lens has a base curve radius of 7.8mm, a diameter of 13.0mm, a center wall thickness of 0.15±0.01mm,
Refractive power -3.34±0.04 diopters, water content 65
%, tensile strength 47Kg/cm ² , light transmittance in saline 97
%, and no shape defects such as lens deformation, burrs, or sink marks were observed. Example 7 In this example, the male molded member 24 and the female molded member 18 in FIG. 4 were made by injection molding polypropylene, and the molded member 3
0 is integrally formed in the female molded member. The spacer 29 used was the same as in Example 6. The first molded portion 22 of the male molded member 24 has a radius of curvature.
The female molding member 2 has a cylindrical shape with a diameter of 8.6 mm and a first optical molding surface 21 of 5.14±0.01 mm.
The second molding part 26 of No. 8 has a cylindrical shape with a diameter of 8.6 mm and has a second optical molding surface 25 with a radius of curvature of 4.71±0.01 mm, and has a liquid reservoir 23. In the above mold, 85 parts by weight of N-vinylpyrrolitone, 15 parts by weight of parabenzyl phenyl methacrylate, and polyethylene glycol dimethacrylate.
The injection was carried out in the same manner as in Example 1 using a polymerizable liquid consisting of 0.5 parts by weight of azobisisobutyronitrile and 0.3 parts by weight of azobisisobutyronitrile. Place a load of 700 grams on the top of the combined mold,
After heating at 60°C for 12 hours and at 90°C for 5 hours in a constant temperature bath, the lens was removed from the mold. Next, the obtained dry lens was immersed in physiological saline and saturated and swelled to form a soft contact lens. This lens has a base curve radius of 7.9mm, a diameter of 13.2mm, a center thickness of 0.36±0.01mm, a refractive index of +4.62±0.05 diopters, and a water content of 73%.
It had excellent properties with a tensile strength of 39 Kg/cm ² and a light transmittance of 98% in saline. Furthermore, this lens had a smooth flat surface, and no defects in shape such as lens shape, burrs, sink marks, etc. were observed. Examples 8 to 11 Polymerizable liquids having various compositions were prepared, and Example 4
Cast polymerization was carried out using the mold shown in FIG. 1 or 4 in accordance with the method of 7 to 7, and the resulting dry lens was saturated and swollen in physiological saline to produce a soft contact lens. Table 1 shows the physical properties of these lenses. Comparative Example 3 2 ml of a polymerizable liquid having the same composition as in Example 4 was poured into a polypropylene polymerization container, the top was sealed, and the container was heated under the same conditions as in Example 4 to polymerize and cure. . When this polymer was taken out from the polymerization container,
Since it is soft, I tried cutting it into a lens shape, but it was impossible. Comparative Example 4 2 ml of the polymerizable liquid having the composition of Example 5 was poured into a polypropylene polymerization container, the upper part of which was sealed, and then heated under the same conditions as in Example 5 to polymerize and cure. This polymer was taken out from the polymerization container, processed into a lens shape by cutting and polishing, and then hydrated and swollen in physiological saline. The obtained soft contact lens was severely deformed, and it was impossible to measure the radius of curvature of the base curve, the diameter, the center wall thickness, and the refractive power. Comparative Example 5 2 ml of the polymerizable liquid having the composition of Example 6 was poured into a polypropylene polymerization container, the top of which was sealed, and then heated under the same conditions as in Example 6 to polymerize and cure. This polymer was taken out from the polymerization container, processed into a lens shape by cutting and polishing, and then hydrated and swollen in physiological saline. The base curve of the obtained soft contact lens had a radius of curvature of 7.8 mm, a diameter of 13.0 mm, and a center wall thickness of 0.15±.
It was 0.01 mm and had a refractive power of -2.87 diopters.
This lens also has a water content of 69% and a tensile strength of 17kg/
^cm2 , and sufficient physical properties could not be obtained.

[Table] Determined by conducting tests and measuring stress at break. The unit is Kg〓cm ² .
*6: Moisture content was determined using the following formula. Moisture content (weight%) =
(W1−W2)÷W1×100
W1 is the weight at saturated water content
W2 is the dehydrated and dry weight of the lens (abbreviation) DMAA N,N-dimethylacrylamide NVP N-vinylpyrrolidone DMMA N,N-dimethylmethacrylamide CHMA cyclohexyl methacrylate AA Acrylic acid BzMA Benzyl methacrylate BPMA p-benzyl phenyl methacrylate BuMA n-Butyl methacrylate 1G Ethylene glycol dimethacrylate 3G Triethylene glycol dimethacrylate 4G Tetraethylene glycol dimethacrylate PG Polyethylene glycol dimethacrylate AIBN Azobisisobutyronitrile ADVN Azobisdimethylvaleronitrile [Effects of the invention] Examples of the present invention The contact lenses obtained by this method all have higher molding accuracy than those shown in the comparative examples, and are particularly characterized by extremely small variations in center thickness and edge thickness. There is. Further, the contact lens obtained according to the present invention does not have the problem of sink marks or burrs around the lens. That is, by using the lens mold according to the present invention, the following excellent effects can be obtained. 1. Contact lenses free of defects such as sink marks and burrs can be manufactured extremely easily and stably without any machining. 2. The molded lenses have extremely high molding precision.
In particular, the variation in center wall thickness and unevenness in edge thickness are extremely small. 3. It is possible to mold objects with extremely diverse designs such as base curves, front curves, bevels, flange curves, peripheral shapes, etc. 4 Because the molded member and spacer are independent,
It is possible to freely select each material, and there is a wide range of usable materials, and the most suitable material can be selected depending on the type of polymerization composition liquid and the required accuracy. 5. Since the spacer does not come into contact with the polymerization composition liquid, the spacer material can be selected without considering problems such as dissolution and deterioration due to the polymerization composition liquid. 6. It can be used for both hard contact lenses and soft contact lenses, and is not limited by the mechanical processability of the contact lens material to be molded. 7. Since the mold according to the present invention can accurately follow polymerization shrinkage and can be made into soft contact lenses with a water content of 40% or more after molding, soft contact lenses with excellent optical precision and mechanical properties are extremely rare. It can be manufactured with a small number of steps and with good reproducibility. 8. Since no mechanical processing is required after molding, soft contact lenses with good physical properties and optical precision can be manufactured without considering the influence of the humidity environment. Such effects of the present invention are achieved by forming a fitting structure in the first molding part of the male molding member and the second molding part of the female molding member, thereby blocking the gap for contact lens molding from the outside,
The polymer composition solution does not come into contact with the air and excess polymer composition solution does not adhere to the surroundings of the lens.The spacer is made of a flexible material, and the volume shrinkage due to polymerization shrinkage is prevented by reducing the wall thickness of the spacer. The thickness of the lens can be absorbed by close contact, the thickness of the lens can be absorbed by the lens, the thickness of the lens can be evenly controlled by correcting the partial unevenness of the lens thickness caused by unevenness of polymerization shrinkage, and the thickness of the lens can be evenly controlled. Due to the unique features of the mold according to the invention, such as the fact that the molding member itself does not deform or shrink, and therefore the critical dimensions such as radius of curvature and diameter of the contact lens to be molded do not change. It will be realized.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway exploded perspective view showing a first embodiment according to the present invention, FIG. 2 is a cutaway front view of the first embodiment, and FIG. 3 is a cutaway front view showing a second embodiment according to the present invention. FIG. 4 is a cutaway front view showing a third embodiment of the present invention, and FIGS. 5 and 6 are cutaway front views showing a comparative example. 1, 11, 21...first optical molding surface, 5, 1
5, 25...second optical molding surface, 2, 12, 22
...First molded part, 6,16,26...Second molded part, 4,14,24...First molded member, 8,1
8, 28... second molded member, 9, 19, 29...
Spacer, 3, 13, 23...Liquid reservoir, 7, 1
7, 27... Spacer installation surface, 10, 20, 3
0... Tsukiate club.

Claims (1)

[Scope of Claims] 1. A male molded member and a female molded member are assembled with a spacer and a lugs for controlling the thickness of the lens interposed on the outer periphery of the molded parts of both molded members. A lens mold characterized by: 2. The male and female molding members have optical molding surfaces;
2. A lens mold according to claim 1, wherein the spacer has a ring shape having a common main axis with the molding member and is located at a position separated from the optical molding surface. 3. The lens mold according to claim 1, wherein the molding member is provided with a liquid reservoir. 4 Claim 3, characterized in that the liquid reservoir is provided in a slope shape around the insertion portion of the female molded member.
Lens mold as described in section. 5. The lens mold according to claim 1, wherein a contact portion for controlling the wall thickness of the lens is integrally formed on the outer periphery of the molding portion of the male molding member. 6. The lens mold according to claim 1, wherein a lever member for controlling the wall thickness of the lens is integrally formed on the outer periphery of the molding part of the female molding member. 7. The lens mold according to claim 1, wherein the mounting portion for controlling the wall thickness of the lens is separate from the molding member and is arranged inside or outside the spacer. 8. The lens mold according to claim 1, wherein the optical molding surface of the male molding member is a substantially convex surface, and the optical molding surface of the female molding member is a substantially concave surface. 9. The lens mold according to claim 1, wherein the optical molding surface of the male molding member is a substantially concave surface, and the optical molding surface of the female molding member is a substantially convex surface. 10. The lens mold according to claim 1, wherein the spacer component is made of a thermoplastic material or a rubber elastic body.