JP2002166436A - Resin mold for producing contact lens and method for producing contact lens using the mold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inexpensively produce a quality contact lens which is excellent in optical properties and has a smooth surface gentle to a cornea and a circular lens fringe. SOLUTION: A resin mold for producing the contact lens by a cast polymerization method is composed of a male mold having a BC engineering surface 1, a diameter and edge-curve regulating contact 2, and an edge-curve molding surface 3; and a female mold having an FC molding surface 4, and a surface 5 contacting the male mold. A polymerizable monomer is packed in a cavity 6 formed by assembling the mold and pressurized/polymerized with a load mounted to produce the lens.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a casting polymerization method, and provides a high-quality contact lens having excellent optics, a corneal-friendly smooth surface and a rounded edge shape at a low cost. The present invention relates to a resin mold for manufacturing a contact lens used for manufacturing, and a method for manufacturing a contact lens using the same.

[0002]

2. Description of the Related Art There are roughly three types of contact lens manufacturing methods, including a lace cut method (cutting and polishing method), a molding method (casting method), and a spin casting method (centrifugal casting method). The lace cutting method is the method most commonly used at present, and is a method of manufacturing a contact lens by cutting a bar-shaped or button-shaped material into a lens shape using a lathe and polishing the material. Although this method has an advantage as a multi-product small-quantity manufacturing method, it has a problem that the number of manufacturing steps is large and complicated, and the cost is high.

The spin casting method is a method for producing a contact lens by utilizing the fact that a raw material spreads thinly by centrifugal force by flowing a polymerizable monomer into a rotating mold, and is suitable for mass production. It has a drawback that it is difficult to obtain sufficient accuracy of the base curve surface, which is one of the important standard shapes as a lens.

In the casting polymerization method, a monomer is injected into a resin mold molded so as to obtain a desired lens, the monomer is polymerized by heat or light, and after polymerization, the lens is removed from the resin mold. Is the law. The advantage of this method is that contact lenses can be manufactured at low cost, but when manufacturing various types of contact lenses having different shapes, various types of resin molds are required, which is disadvantageous for such manufacturing. There is also. However, in the case of a soft contact lens, there are few types of BC (base curve: curvature of the surface where the contact lens contacts the cornea) and few types of molds are required, so that this method can be applied. Further problems with the casting polymerization method include the roundness of the shape of the lens edge, the problem of cracking during the polymerization or release of the lens, the problem of bubble formation during the polymerization of the lens, and the problem of polymer lenses and resin molds. (Or moderate adhesiveness).

[0005]

In recent years, soft contact lenses have been used by many people because of their good wearing sensation. Furthermore, disposable soft contact lenses are rapidly spreading because they do not require troublesome care such as cleaning and disinfection of contact lenses and are easy and hygienic. This disposable lens has a great feature that it is inexpensive, and a casting polymerization method that can produce a large number of contact lenses of the same standard at low cost is suitable for this.

One of the quality problems of the cast polymerization method is the green shape of the lens. Originally, soft contact lenses are made of soft materials themselves and are softly attached to the cornea. However, in order to improve the feeling of wearing, it is desirable that the edge of the lens has a smooth circular shape and gently contacts the cornea. In the casting polymerization method, a contact lens is manufactured by filling a polymerizable monomer into a resin-type space in which a male mold and a female mold are combined and polymerizing the same. Therefore, the edge of the lens is generally square. An object of the present invention is to manufacture a low-cost high-quality contact lens having excellent optical properties and having a smooth surface that is gentle on the cornea and a greenish round lens.

Further, as a problem in the production of the casting polymerization method, there is a crack (crack, chip, crack) which occurs at the time of polymerization of the lens or at the time of releasing from the resin mold, which is a major factor in lowering the production yield. I have. Another problem in the production is that bubbles are generated in the lens during polymerization of the lens.
In this regard, when degassing the monomer under reduced pressure or injecting the monomer into the resin mold, measures are taken, such as injecting the resin while lightly contacting the tip of the injection nozzle with the resin mold, but this is not sufficient. Another problem is to fill polymerizable monomer into the space where the male and female molds are combined, polymerize by light or thermal polymerization, remove the female mold, attach the male mold to a lathe for cutting, In the method of manufacturing a contact lens by cutting the front curve side (blank mold method), it is essential that the lenticular polymer adheres to the male side when separating the male and female molds is there.
As a countermeasure, a method of producing a male mold or a female mold with a different resin, or a method of plasma or chemical surface treatment is used, but is not always sufficient.

[0008]

SUMMARY OF THE INVENTION According to the present invention, there is provided a method for producing a contact lens by a cast polymerization method, comprising a resin mold for producing a contact lens having a smooth surface which is gentle to the cornea, and a rounded edge shape. A method of filling a polymerizable monomer into a resin mold and producing a contact lens by light or thermal polymerization, or filling a polymerizable monomer into a space combining a male mold and a female mold and polymerizing by light or thermal polymerization, A method of manufacturing a contact lens by removing a mold, attaching a male mold to a lathe for cutting, and cutting the front curve side of the lens, and at this time, a toric lens as well as a spherical lens can be manufactured.

The resin mold for producing a contact lens according to the present invention is a method of producing a contact lens by filling a polymerizable monomer into a space in which a male mold and a female mold are combined, and producing the contact lens by light or thermal polymerization. After filling the combined space with polymerizable monomer and polymerizing by light or thermal polymerization, remove the female mold, attach the male mold to a lathe for lens cutting, and cut the front curve side of the lens to manufacture a contact lens Any of the methods can be used.

Next, the resin mold for producing a contact lens according to the present invention will be described. 1 and 2 are sectional views of a male mold for producing a contact lens according to the present invention, FIG. 3 is a sectional view of a female mold, and FIG. 4 is an assembled sectional view of a resin mold for producing a contact lens according to the present invention. FIG. 5 is an enlarged view of a contact portion before and after polymerization when a male mold and a female mold of a resin mold for producing a contact lens according to the present invention are combined.

As shown in FIGS. 1 and 2, a male mold for producing a contact lens is filled with a polymerizable monomer, polymerized and molded into a lens shape. And a sharp contact portion 2 with a female mold for regulating an edge curve, and a curved surface 3 for forming an edge curve of a lens. On the other hand, the female mold is FC (front curve) when molded into a lens shape as shown in FIG.
, And a contact surface 5 when a male mold is inserted after filling the polymerizable monomer and the molds are combined. The male BC optical surface 1 and the female FC optical surface 4 for forming the contact lens shape are processed into sufficiently smooth mirror surfaces.

When these male and female molds are combined, the assembled sectional view shown in FIG. 4 is obtained, and a lens-shaped space (cavity) 6 is formed between the BC optical surface 1 and the FC optical surface 4. The contact lens is obtained by filling the polymerizable monomer into the cavity and polymerizing it.

On the other hand, a semifinished product (blank) of a contact lens in which only the BC of the contact lens is formed is prepared by a molding method, and then the blank is mounted on a lathe.
A contact lens can also be manufactured by cutting FC. In this case, it is necessary to make the cavity 6 shown in FIG. 4 a thickness that can be cut, and the length (depth) of the contact portion 2 with the male and female molds shown in FIGS.
Can be achieved by adjusting

FIG. 5 is an enlarged view of an edge curve regulating contact portion before and after polymerization when a male mold and a female mold are combined. The part 8 is bent inwardly, thereby forming a rounded edge.

Next, a method for polymerizing a contact lens according to the present invention will be described. The polymerization of the present invention is carried out by adding a polymerization initiator to a polymerizable monomer and heating or irradiating with ultraviolet rays. Specifically, first, a predetermined amount of a polymerizable monomer, a cross-linking agent, and a polymerization initiator are prepared, a predetermined amount of this polymerization solution is injected into a female concave surface, and then a male convex surface is overlapped. At this time, it is important that the male contact portion and the female contact surface make complete contact, and in some cases, it is important to apply a load to the male mold to complete the contact. A contact lens can be obtained by injecting the polymerization liquid and heating the assembled mold to thermally polymerize it, or by photopolymerizing with ultraviolet light. The polymerization apparatus used for the polymerization has a structure in which the inside can be replaced with nitrogen, and in some cases, a structure capable of performing pressure polymerization at a low pressure (within several kg / cm2) is desirable. Furthermore, it is necessary that a control device capable of freely adjusting the polymerization temperature and time be installed.

The polymerizable monomer used in the present invention is not particularly limited as long as it is a monomer generally used as a material for a contact lens, and may be used alone or in combination of two or more. Examples of the monomer include (meth) acrylic acid or esters thereof. Specifically, hydrocarbon derivatives such as methyl (meth) acrylate and ethyl (meth) acrylate, 2-trifluoroethyl (meth) acrylate, hexafluoro-propyl (meth) acrylate, 2,2,2-trifluoroethyl- 2-methyl-2
-Fluorine-containing (meth) acrylates such as propenoate, and tris (trimethylsiloquin) silylpropyl (meth) acrylate, tris (dimethylsiloquin) silylpropyl (meth) acrylate 3- (3,3,3-trimethyl) Silicon-containing (meth) acrylates such as -1,1-bis (trimethylsiloxy) disilanoxyl) propyl methacrylate, 2-hydroquinethyl (meth) acrylate, 2-hydroquinpropyl (meth) acrylate, (meth) acrylamide, And hydrophilic monomers such as N, -dimethyl (meth) acrylamide and N-vinylpyrrolidone.

Further, as a crosslinking agent, ethylene glycol di (meth) acrylate, dimethylene glycol (meth)
Polyfunctional monomers such as acrylate and propylene glycol di (meth) acrylate can be used. The above monomers are polymerized in the presence of a radical polymerization initiator in one kind or a combination of two or more kinds. Radical polymerization initiators include benzoyl peroxide, lauroyl peroxide, azobisisobutyronitrile, azobis (2.
4-dimethylvaleronitrile) and the like. In the case of photopolymerization, benzoin ethers such as 2.4,6-trimethylbenzoyldiphenylphosphine oxide are used. The amount of these initiators used is preferably 0.01 to 2% by weight based on the total amount of monomers used.

Next, the method for polymerizing a contact lens according to the present invention will be described in more detail. First, a resin mold having the design of the present invention is manufactured by an injection molding method. Next, a predetermined amount of a polymerizable monomer, a crosslinking agent and a polymerization initiator are prepared, and the mixture is degassed under reduced pressure by a vacuum pump. The polymer solution is first poured into a concave portion of the female resin mold under a predetermined amount by a dispenser, and then the male convex surface is overlapped. At this time, it is important in the present invention that the acute contact portion of the male mold and the contact surface of the female mold completely contact each other, and a load is placed on the male mold to complete the contact. Next, the resin mold filled with the polymerization liquid and assembled and loaded with a load is placed on a tray and placed in a polymerization apparatus. The polymerization equipment is connected to a nitrogen line.After the inside of the equipment is replaced with nitrogen, the pressure is increased to 0 to 5 kg / cm2 with nitrogen.However, the pressure may be changed during polymerization, so a pressure control device must be installed. Is preferred. Next, the temperature of the polymerization apparatus is raised to start the polymerization, and the polymerization temperature is preferably gradually raised from 30 ° C. to 120 ° C., and the polymerization time is preferably 12 to 24 hours in conjunction with the polymerization temperature.
Generally, the polymerizable monomer shrinks as the polymerization proceeds, which may cause distortion, bubbles, or cracks in the polymer. The present invention adjusts the temperature and pressure as the polymerizable monomer filled in the cavity 6 shown in FIG. 4 shrinks as the polymerization proceeds, and as shown in FIG. The sharp contact portion 8 is characterized by being curved inward and bent to form a rounded edge curve and to prevent generation of distortion, bubbles, and cracks. Further, since the sharp contact portion 8 of the male mold is curved inwardly and bent, the lenticular polymer can be held by the male mold. In the case of the blank molding method, the lenticular polymer must be a male mold. There is also the advantage that it is attached to the side.

[0019]

The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.

(Example 1) A polypropylene resin was used as a molding material for a resin mold, the curvature of the male BC optical surface in FIG. 1 was 7.84 mm, the diameter was 12.3 mm, and the female FC in FIG. The resin side was manufactured by injection molding with the curvature of the optical surface being 8.33 mm. 98 parts by weight of 2-hydroxyethyl methacrylate as a monomer used for polymerization,
2 parts by weight of ethylene glycol dimethacrylate and 0.2 part by weight of azobis (2.4-dimethylvaleronitrile) were mixed well, and degassed and purged with nitrogen. Filled. Further, a load of 3 g was placed on the resin mold filled with the monomer, and this was put into a hot-air circulating constant temperature bath. After nitrogen replacement, the pressure was increased to 0.3 kg / cm2 with nitrogen, and the pressure was increased at 40 ° C for 2 hours. Heat at 50 ° C. for 2 hours, 70 ° C. for 5 hours, 90 ° C. for 5 hours. The obtained contact lens was taken out of the resin mold, swollen in pure water, washed, and then immersed in physiological saline to complete the water absorption and swelling. The soft contact lens thus obtained has a smooth and rounded edge shape, no distortion, bubbles and cracks are observed, the diameter is 14.0 mm, the BC is 8.70 mm, and the power is Is -3.
00.

(Embodiment 2) Using a polypropylene resin as a molding material for the resin mold, the contact portion 2 with the male and female molds shown in FIG.
A resin mold was manufactured by injection molding with the curvature of the C optical surface being 7.84 mm, the diameter being 12.3 mm, and the curvature of the female FC optical surface shown in FIG. 3 being 8.00 mm. 2-hydroquinethyl methacrylate 9 as a monomer used for polymerization
8 parts by weight, ethylene glycol dimethacrylate 2 parts by weight, azobis (2.4-dimethylvaleronitrile) 0.
Two parts by weight were mixed well, degassed and purged with nitrogen, and filled in the cavity of the sectional view shown in FIG. Further, a 5 g load was placed on the resin mold filled with the monomer, and this was put into a hot-air circulating constant-temperature bath. After the atmosphere was replaced with nitrogen, the pressure was increased to 0.5 kg / cm2 with nitrogen.
Heat at 50 ° C. for 2 hours, 70 ° C. for 5 hours, 90 ° C. for 5 hours. When the female mold was removed from the obtained resin mold, the lenticular polymer adhered to the male mold. The male mold was attached to a lathe for cutting a lens, and the FC side of the lens had a curvature of 8.3.
It was processed to 3 mm. The obtained contact lens was taken out of the resin mold, swollen in pure water, washed, and then immersed in physiological saline to complete water absorption and swelling. The soft contact lens thus obtained has a smooth and rounded edge shape, no distortion, no bubbles and no cracks are generated, the diameter is 14.0 mm, and the BC is 8.
70 mm, power was -3.00. Similarly, when the lens is processed to have a curvature of 8.37 mm on the FC side and then swelled with water, the power of the soft contact lens becomes -3.
It was 50. A semi-finished product of a contact lens in which only the contact lens BC is formed (blank)
Is manufactured by a molding method, a blank is mounted on a lathe, and a cutting process is performed while changing the FC, whereby lenses of various types of power can be manufactured. In this case, the number of types of resin molds can be significantly reduced, which is economical.

Example 3 A polypropylene resin was used as a molding material for the resin mold, the curvature of the male BC optical surface in FIG. 1 was 7.76 mm, the diameter was 12.2 mm, and the female FC in FIG. A resin mold was manufactured by injection molding with the curvature of the optical surface set to 8.26 mm. 65 parts by weight of 2-hydroxyethyl methacrylate as a monomer used for polymerization,
30 parts by weight of N-vinylpyrrolidone, 3 parts by weight of methacrylic acid, 2 parts by weight of ethylene glycol dimethacrylate, and 0.5 part by weight of azobis (2.4-dimethylvaleronitrile) were mixed well and degassed and replaced with nitrogen. This was filled in the cavity of the sectional view shown in FIG. further,
A load of 2 g was placed on the resin mold filled with the monomer, and this was put into a hot-air circulating constant temperature bath. After nitrogen replacement, the pressure was increased to 0.1 kg / cm 2 with nitrogen, and the temperature was increased to 40 ° C. for 2 hours at 50 ° C. For 2 hours, 70 ° C. for 5 hours, and 90 ° C. for 5 hours. The obtained contact lens was taken out of the resin mold, swollen in pure water, washed, and then immersed in physiological saline to complete water absorption and swelling. The soft contact lens thus obtained has a smooth and rounded edge shape, no distortion, bubbles, or cracks are observed, the diameter is 14.5 mm, and the BC is 9.00 mm. The power was -3.00.

(Example 4) The molding material of the resin mold is polypropylene resin, the curvature of the male BC optical surface of FIG. 1 is 7.80 mm, the diameter is 8.00 mm, and the male FC of FIG.
A resin mold was manufactured by injection molding with the curvature of the optical surface set to 8.10 mm. As monomers used for the polymerization, 12 parts by weight of methyl methacrylate, 8 parts by weight of methacrylic acid, 24 parts by weight of 2,2,2-trifluoroethyl-2-methyl-2-fluorophenolate, 3- (3,3,3-trimethyl- 1,1-Phase (trimethylsiloxy) silanoxyl) fluoromethacrylate 5
0 parts by weight, ethylene glycol simethacrylate 6 parts by weight, asbestos (2,4
-0.5% by weight of dimethylvaleronitrile)
The nitrogen-substituted one was filled in the cavity portion of the assembly sectional view shown in FIG. Further, a load of 2 g was placed on the resin mold assembled and charged with this monomer, and this was charged into a hot-air circulating constant temperature bath, and after purging with nitrogen, 0.2 g of nitrogen was added.
It was pressurized to kg / cm 2 and heated at 60 ° C. for 10 hours and at 90 ° C. for 5 hours. The contact lens thus obtained has a smooth, rounded edge shape, distortion,
No formation of bubbles or cracks was observed. The spherical accuracy and optical performance of this contact lens were extremely excellent.

[0024]

According to the present invention, a resin mold for producing a contact lens and a method for producing a contact lens using the resin mold have a smooth surface which is excellent in optical properties and is gentle on a cornea, and a rounded lens edge. High quality contact lenses can be manufactured at low cost.

[Brief description of the drawings]

FIG. 1 is a sectional view of a male mold for manufacturing a contact lens used in Examples 1 and 3 of the present invention.

FIG. 2 is a sectional view of a female mold for manufacturing a contact lens used in an example of the present invention.

FIG. 3 is a sectional view of a female mold for manufacturing a contact lens used in an example of the present invention.

FIG. 4 is an assembled sectional view of a resin mold for manufacturing a contact lens used in an example of the present invention.

FIG. 5 is an enlarged view of a contact portion before and after polymerization when a male mold and a female mold of a resin mold for contact lens production used in an embodiment of the present invention are combined.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 BC optical surface 2 Diameter and edge curve normalization contact part 3 Edge curve molding surface 4 FC molding surface 5 Contact surface when male mold is inserted 6 Space (cavity) which becomes lens shape 7 Attachment when attaching to lathe 8 Diameter Before and after superposition of the contact part of the edge and edge curve regulation

Claims (6)

[Claims] In a casting polymerization method in which a polymerizable monomer is filled in a space in which a male mold and a female mold are combined and a contact lens is manufactured by photopolymerization or thermal polymerization, a smooth surface and a round surface friendly to the cornea are obtained. A resin mold for manufacturing contact lenses with an edge shape. 2. A male edge curve forming surface (3) devised for forming a rounded edge according to claim 1 and a knife edge type surface for facilitating formation of an edge curve. A resin mold for manufacturing a contact lens having a female contact portion (5) having a curved surface for receiving a female mold contact portion (2) and a male knife edge type contact portion in a smooth. 3. A space in which a male mold and a female mold are combined is filled with a polymerizable monomer, polymerized by photopolymerization or thermal polymerization, the female mold is removed, and the male mold to which the lenticular polymer is adhered is formed into a lens. A resin mold for producing a contact lens, wherein the resin mold is attached to a lathe for cutting, and the front curve side of the lens is cut to produce a contact lens. 4. After polymerization by a casting polymerization method, the female mold is removed, the male mold to which the lenticular polymer is adhered is mounted on a lathe for cutting a lens, and the front curve side of the lens is cut to form a contact. A resin mold for producing contact lenses, which is capable of producing not only spherical lenses but also toric lenses when producing lenses. 5. The material of the resin mold is PP (polypropylene),
A resin mold for producing contact lenses, which is an injection-moldable synthetic resin such as polyolefin such as PE (polyethylene), PS (polystyrene), PC (polycarbonate), PMMA (polymethyl methacrylate), polyacetal, and polyamide. . 6. A resin mold for producing a contact lens according to claim 1, which has a shape which facilitates the automation of the production process when producing the contact lens, and a resin mold for producing the contact lens. A method for producing a contact lens, which is used.