JPH0825378A - Resin mold for producing contact lens and production of contact lens - Google Patents

Abstract

PURPOSE:To inexpensively produce a contact lens of high quality excellent in optical properties and mechanical strength and having a smooth surface and edge imparting no damage to the cornea. CONSTITUTION:The production of a contact lens is performed by a blank molding method due to thermosetting and, as the material quality of a resin mold used therein, a resin capable of sufficiently withstanding thermosetting and thermal annealing and susceptible to cutting processing using a lathe is used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for producing a high quality contact lens having excellent optical property and mechanical strength and having a smooth surface and edge which does not damage the cornea at low cost. The present invention relates to a resin mold for manufacturing a contact lens, and a method for manufacturing a contact lens.

[0002]

2. Description of the Related Art Contact lenses are roughly classified into three types of manufacturing methods, that is, a race cutting method (cutting and polishing method), a molding method and a spin casting method (centrifugal casting method). . The race cut method is the most commonly used method for manufacturing contact lenses at present, and is a method for manufacturing a contact lens by cutting out a rod-shaped or button-shaped contact lens material with a lathe, cutting and polishing it. . This method is suitable for manufacturing a wide variety of contact lenses having different shapes such as BC (base curve: the surface where the contact lens contacts the cornea, or the curvature of that surface), but the manufacturing cost is high. There's a problem. Currently, most hard contact lenses are manufactured by this race cut method, and many manufacturers also manufacture soft contact lenses by the race cut method.

On the other hand, the molding method and the spin casting method are mostly used in the production of soft contact lenses. The molding method is a method of filling a mold having a lens-shaped space with a polymerizable monomer, and polymerizing this to manufacture a contact lens.The spin casting method is to cast the polymerizable monomer into a rotating mold and centrifugal force. This is a method of manufacturing a contact lens by utilizing that the raw material spreads thinly. The drawback of these methods is that they are disadvantageous when flexibly manufacturing a wide variety of contact lenses of different shapes, but in the case of soft contact lenses, the type of BC required is small and the type required. Because of the small number of types, it is possible to apply these methods. On the other hand, the advantage of these methods is that contact lenses can be manufactured at low cost, but their accuracy, specifically dimensional accuracy and surface accuracy, both greatly depend on the accuracy of the mold, and a highly accurate mold is required. If used, it is possible to manufacture high quality contact lenses. However, the spin casting method needs to control many factors such as the viscosity, surface tension, amount, and rotation speed of the polymerizable monomer, and the applicable lens material is limited to a specific one. Further, the contact lens obtained by this method is also an aspherical surface, so that sufficient optical performance cannot be obtained.

In recent years, soft contact lenses have been widely used by people who have not been able to wear conventional hard contact lenses because of their good wearing sensation, and even in Japan where a large proportion of hard contact lens wearing populations were used in the past. The proportion of contact lens wearers is increasing.
Therefore, various techniques for manufacturing a low-cost, high-quality soft contact lens have been carried out by researchers or engineers. A feature of soft contact lenses is that they do not require as many types of BC as hard contact lenses, because the lenses themselves are flexible and are mounted along the shape of the cornea. Therefore, it is considered that the molding method is suitable for manufacturing a contact lens with low cost and little variation in quality,
As described above, the molding method has a problem that it is not possible to flexibly manufacture a wide variety of contact lenses having different shapes and the quality of the edge shape is limited. As an effective means to solve the problems of this molding method, a molding method that can manufacture contact lenses with little variation in quality at low cost, and a race cut method that can flexibly manufacture a wide variety of contact lenses with different shapes A method combining the above is proposed. This method is called a blank molding method in the sense that the semi-finished lens is manufactured by the molding method.

The blank mold method is used for BC of a small number of types.
The surface is formed by the molding method, and the FC (front curve: the surface opposite to the surface where the contact lens contacts the cornea, or the curvature of that surface) is formed by cutting the surface to an arbitrary curvature by the race cut method. In addition to being able to freely set the frequency and center thickness, the bite can be BC
There is a feature that the edge can be easily formed by cutting into the surface.

When a contact lens is manufactured by this method, a BC surface of the lens is formed by a resin mold manufactured by injection molding, and then a lathe for cutting a lens with the semifinished lens product attached to the resin mold. To form the FC surface and the edge portion. Further, the FC surface and the edge portion formed by cutting do not damage the cornea when wearing the contact lens,
Must be smoothly polished. At this time, the semi-finished lens product is required to have sufficient adhesiveness to withstand the stress applied during processing in the process of cutting or polishing the FC surface and the edge portion. Moreover, after the cutting and polishing steps are performed to form the lens shape, releasability is required so that the lens shape can be easily peeled off by hydration with water. That is, it is necessary that the adhesiveness and the releasability are well balanced between the resin mold used for the blank molding method and the lens material.

Conventionally, as the material of resin molds for manufacturing contact lenses, polyolefins such as PP (polypropylene) and PE (polyethylene), PS (polystyrene), PC (polycarbonate), PMMA (polymethylmethacrylate), Teflon, nylon are mainly used. For example, injection-moldable synthetic resins are widely used. It is necessary to consider various factors in order to select the material used for the resin mold for manufacturing the contact lens from these.

First, compatibility with contact lens materials can be mentioned. The material of the resin mold for manufacturing contact lenses is
It must not be eroded when it comes into contact with various polymerizable monomers that are raw materials for contact lenses. This depends on the type of polymerizable monomer used. Further, as described above, the adhesion with the contact lens material is also a big problem. For example, when the adhesion between the material of the resin mold for manufacturing a contact lens and the contact lens material is too large, there is a problem that the contact lens material cannot be released after being polymerized. On the contrary, if the adhesion is too small, the polymerizable monomer, which is the raw material of the contact lens, is easily peeled off from the resin mold in the process of polymerization, and the shape of the resin mold is not accurately transferred to the contact lens. Become. That is, it is necessary to select the material of the resin mold for manufacturing the contact lens so that the adhesiveness with the contact lens raw material becomes appropriate.

Next, the relationship with the polymerization method or the polymerization conditions can be mentioned. The polymerizable monomer that is a raw material of the contact lens is usually polymerized and cured by heating or irradiation with an active energy ray such as ultraviolet ray in the presence of a polymerization initiator. In the case of the present invention, since it is carried out by thermal polymerization, the resin mold used therefor must have a certain degree of heat resistance.

Further, the precision as a resin mold for manufacturing a contact lens can be mentioned, which is closely related to a molding method such as injection molding. The precision as a resin mold for manufacturing a contact lens specifically refers to dimensional precision and surface precision, which largely depend on the material of the resin used. In particular, it is known that volumetric shrinkage during molding and water absorption after molding have a great influence on the accuracy of the resin mold.

In addition to these elements, the cost and moldability of the resin mold material, and in the present invention, since the resin mold needs to be cut by a lathe for lens cutting, the workability and the machinability of the resin mold can be improved. Is also an important factor.

[0012]

The greatest advantage of manufacturing contact lenses by a molding method is that contact lenses of the same standard can be mass-produced and low-cost production is possible.

In recent years, cleaning of soft contact lenses,
Disposable soft contact lenses are rapidly becoming popular mainly in the United States because they do not require troublesome care such as boiling disinfection and are hygienic.
In order to manufacture this disposable soft contact lens, it is necessary to significantly reduce the conventional manufacturing cost, but the quality cannot be deteriorated because the contact lens is a medical device that directly contacts the cornea.

As a problem to be solved by the present invention, first, there is a kind of material used for the resin mold. Currently, PP, which is said to be the most commonly used material for resin molds for manufacturing contact lenses, is called polyolefin along with PE and the like. Polyolefin is generally inexpensive and can be easily molded by injection molding or the like. Further, since it has a certain degree of transparency, it can be applied to polymerization by light rays. However, the volumetric shrinkage of a polyolefin is relatively large during molding, and it is difficult to obtain accuracy. Moreover, since the heat resistance is poor, the polyolefin may be deformed even at a relatively low temperature. Therefore, it cannot be said that it is suitable when manufacturing a contact lens by thermal polymerization. PS has higher heat resistance and better transparency than PP, but has poor solvent resistance. PC,
As PMMA is used as various optical materials, it has excellent transparency, PC has high heat resistance, and PMMA has the characteristics that accuracy can be easily obtained, but both have solvent resistance. It is relatively poor and can be eroded, especially for the polymerizable monomers commonly used as contact lens materials. Further, it has a drawback that it has a large adhesiveness with a contact lens material and is difficult to release.

Next, the problems associated with the polymerization of contact lenses will be described. At present, the polymerization of contact lenses is mainly carried out by thermosetting. Particularly, it can be said that most of the polymerization of the bar material or the button which is the contact lens material used in the lace cut method is manufactured by thermosetting. The molding method and the spin casting method are manufactured not only by heat curing but also by light curing. Here, the effect on the lens characteristics due to the difference in the curing method between heat curing and light curing will be described. Generally, it is said that the copolymer obtained by thermosetting has excellent mechanical strength characteristics as compared with the copolymer obtained by photocuring. Thermal curing is the cleavage of a small amount of thermal catalyst added to the polymerizable monomer by heating to generate radicals,
Polymerization of the polymerizable monomer is carried out by repeating a chain reaction in which the radical attacks and bonds with the polymerizable monomer. Photocuring, like thermosetting, causes a small amount of a photocatalyst added to a polymerizable monomer to be cleaved by irradiation of active energy rays such as ultraviolet rays to generate radicals, thereby polymerizing the polymerizable monomer. However, the major difference here is that the photocatalyst is cleaved at the same time and rapidly by irradiation of light rays to generate radicals, so that the degree of polymerization tends not to be sufficiently large as compared with thermosetting. . Therefore, the copolymer produced by photo-curing has a smaller molecular weight than the copolymer produced by heat-curing, and has a mechanical strength property, for example, in the case of a soft contact lens, strength against pulling, strength of a hard contact lens. In this case, the strength against bending is considered to be poor.

On the other hand, the photo-curing can complete the curing in a very short time as compared with the heat-curing, and has a great manufacturing advantage. However, in order to obtain a high-quality contact lens having sufficient mechanical strength, which is the object of the present invention, it can be said that production by thermosetting is currently suitable.

The method of manufacturing a contact lens of the present invention comprises:
It is a thermosetting method using a blank mold method. The problem here is the problem of uniformity of the copolymer after curing the polymerizable monomer. In contact lens polymerization, polymerization strain resulting from non-uniformity of copolymerization is often a problem. Conventionally, as a means for eliminating this polymerization strain, in the case of a bar material or a button which is a contact lens material used in the lace cut method, it has been carried out by optimizing the polymerization conditions or a method such as heat annealing after polymerization. However, it is a very difficult task to completely eliminate the polymerization distortion. In particular, it is not so difficult in the case of a single component as the polymerizable monomer, but in the case of copolymerization by a plurality of components, this can be a serious problem.

The above has described the problems in terms of the resin material and shape of the resin mold for producing a contact lens, or the non-uniformity at the time of polymerization. However, it is still necessary to sufficiently satisfy the characteristics required for a contact lens. The reality is that no resin mold and manufacturing method for manufacturing such contact lenses have been found. In particular, in the case where the contact lens is a medical device and its precision is strictly required, the present invention provides a high quality product having a smooth surface and an edge which is excellent in optical property and mechanical strength and does not damage the cornea. The objective is to manufacture a simple contact lens at low cost.

[0019]

That is, the resin mold for producing a contact lens of the present invention is prepared by filling a polymerizable monomer in a space formed when a male mold and a female mold are combined and heating the same. After polymerization, attach the male mold to the lens cutting lathe with the two molds still matched or with the female mold removed, and use it for the method of manufacturing the contact lens by cutting the front curve side of the lens The mold is characterized in that the material of the resin mold is a resin that can sufficiently withstand heat curing and heat annealing, and is made of a resin that can be cut by a lathe.

Further, the space formed when the male mold and the female mold are combined is filled with a polymerizable monomer, and the polymerizable monomer is heated to polymerize it. It is a mold used in the method of manufacturing a contact lens by attaching the male mold to the lathe for lens cutting in the removed state and cutting the front curve side of the lens, and combining this resin mold male mold and female mold The thickness of the space formed at this time is 0.3 mm or more.

Also, in the method for manufacturing a contact lens of the present invention, the material of the resin mold is a resin that can sufficiently withstand thermosetting and heat annealing, and is made of a resin that can be cut by a lathe. After filling the space between them with a polymerizable monomer and heating it to polymerize, the male mold is used for lens cutting with the two molds still matching or with the female mold removed. It is characterized by being attached to a lathe and cutting the front curve side of the lens.

Further, the male mold and the female mold are combined so that the thickness of the space formed is 0.3 mm or more,
Fill the space formed between them with a polymerizable monomer and heat it to polymerize, then attach the male mold to the lens cutting lathe with the two molds still matching or with the female mold removed. , The front curve side of the lens is cut.

The present invention will be described in detail below.

The resin mold for producing a contact lens of the present invention is a resin mold used in a blank molding method in which the BC surface of a contact lens is formed by a molding method and the FC surface is formed by a race cut method. Furthermore, it is characterized in that the polymerizable monomer in the mold is cured by heat.

First, the materials used for the resin mold of the present invention will be described. Since the contact lens of the present invention is manufactured by thermosetting as described above, the resin material used for the contact lens must have heat resistance to some extent. That is, it is necessary to maintain sufficient dimensional accuracy and surface accuracy required for a contact lens in a temperature range of 20 to 100 ° C. which is a temperature range generally used for thermosetting of a polymerizable monomer. further,
Generally, in the production of contact lenses by thermosetting, heating at 100 ° C. or higher may be performed during annealing.
The purpose of the heat annealing is to improve the homogeneity of the copolymer and to remove active sites that may remain in the copolymer, as described above. Must not deform at this annealing temperature.

On the other hand, since the contact lens manufacturing method of the present invention is the blank molding method, it is necessary to cut the FC surface by a lens cutting lathe after forming the BC surface by the molding method. Further, in order to process the edge portion that influences the wearing feeling of the contact lens into a smooth curved shape, it is necessary to cut the blade of the turning tool of the lathe into the resin mold. Therefore, for the resin mold used in the present invention, a resin that can be cut by a lathe must be selected.

Therefore, as the material which can be used as the resin type material of the present invention, polyamide, ethylene-vinyl alcohol copolymer, polyacetal, polyester and polysulfone, which are generally heat-resistant and machinable resins, are used. , Amorphous polyolefins and the like, and of these, the type of polymerizable monomer used,
The polymerization or annealing temperature, cutting conditions, etc. are taken into consideration, and the adhesiveness with the lens material is also taken into consideration and selected as described above. In particular, ethylene-vinyl alcohol copolymer is less likely to be eroded by the (meth) acrylic acid ester that is generally used as a contact lens raw material, and can be used in a very wide range of contact lens raw materials, so that it is a suitable material. I can say.

Next, the resin mold for producing a contact lens of the present invention will be described. A semi-finished product (blank) of a contact lens, in which only BC of the contact lens is formed, is manufactured by a molding method, and then FC is secondarily processed to obtain a resin mold used in a method for obtaining a contact lens as shown in FIGS. It will be described in 3). FIG. 1 is a sectional view of a male contact lens resin mold according to the present invention, FIG. 2 is a sectional view of a female mold, and FIG. 3 is an assembled sectional view showing a coupled state of the contact lens resin mold according to the present invention.

As shown in FIG. 1, the male mold of this contact lens molding die is a convex BC optical surface 1 which forms BC when molded into a contact lens shape, and a mold after filling with a polymerizable monomer. It is composed of a contact surface 2 of a mold which comes into contact when assembled, and an attachment 3 which is mounted on a lathe for lens cutting after superposition. The convex BC optical surface 1 that forms BC when formed into a contact lens shape is processed into a sufficiently smooth mirror surface. On the other hand, as shown in FIG. 2, the female mold has a concave FC forming surface 4 for forming the FC of the contact lens after polymerization and cutting, and a contact surface of the mold which is contacted when the mold is assembled after filling the polymerizable monomer. 5. It is composed of a side surface contact surface 6 of a die for preventing the FC surface and the BC surface from being displaced in position.

When the male mold and the female mold are matched and assembled, a lens-shaped space (cavity) 7 is formed between the FC forming surface and the BC optical surface as shown in FIG. After the polymerizable monomer is filled in the tee and polymerized, the male mold is attached to the lens cutting lathe via the attachment while the two molds are still matched or the female mold is removed, and the FC of the lens is attached. The side is cut to obtain a contact lens.

At this time, one point is how to set the thickness of the blank. As mentioned above, one of the problems in manufacturing contact lenses is
This is a problem of uniformity of the copolymer after curing the polymerizable monomer. In other words, in the polymerization of contact lenses, the polymerization strain resulting from the non-uniformity of copolymerization is often a problem, but this phenomenon is not limited to the case of manufacturing by the race cut method, but also the case of manufacturing by the molding method or spin casting method. Occurs similarly. When manufacturing a lens by the molding method, the thickness of the cavity described above is the target lens thickness, so 0.03 mm to 0.2 mm
And it will be very thin. For this reason, the chain reaction due to the polymerization does not proceed uniformly, and causes polymerization distortion. Furthermore, oxygen acts as a substance that inhibits the polymerization during the polymerization process, but if the cavity is not thick enough, it is easily affected by oxygen, causing non-uniformity of the polymerization, which also causes polymerization strain. Cause. Therefore, in the present invention, by setting the thickness 8 of the cavity to 0.3 mm or more, it becomes possible to significantly reduce the occurrence of polymerization distortion. The required thickness of the cavity depends on the type of the polymerizable monomer used and the polymerization conditions, but is generally 0.3 mm or more. It is more preferably 0.5 mm or more, and it is considered that the uniformity of polymerization is improved as the thickness of the cavity is increased. However, if it is increased more than necessary, not only a large amount of the polymerizable monomer is consumed but also cutting work is performed. Since the size of the portion to be increased increases the cost, it is desirable to set the value appropriately within the range of 0.5 to 1.0 mm.

Next, the method for polymerizing the contact lens according to the present invention will be described. The polymerization of the present invention is carried out by heat curing by heating in the presence of a usual heat catalyst. A necessary amount of the polymerizable monomer is discharged onto the concave surface of the female mold, and the polymerizable monomer is superposed on the concave surface so that the convex surface of the male mold matches the concave surface. At this time, be careful that the contact surface of the mold and the contact surface of the side surface are in complete contact. It is suitable to heat the thus assembled mold in an atmospheric polymerization furnace or a hot water polymerization tank to carry out thermal polymerization.

The polymerizable monomer applicable to the present invention is
A commonly used radically polymerizable compound,
It is a compound containing at least one vinyl group, allyl group, acryl group, or methacryl group in the molecule, and is a substance that is usually used as a hard contact lens or soft contact lens material. Specifically, alkyl (meth)
(Meth) such as acrylate, siloxanyl (meth) acrylate, fluoroalkyl (meth) acrylate, hydroxyalkyl (meth) acrylate, polyethylene glycol (meth) acrylate, (meth) acrylic acid ester of polyhydric alcohol, vinyl (meth) acrylate Examples thereof include acrylic acid esters, styrene derivatives, N-vinyl lactam, vinyl compounds such as vinyl (polyvalent) carboxylate, and the like. More specifically, for example, styrene, acrylic acid, methyl acrylate, ethyl acrylate, n-butyl acrylate, phenyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, n. -Butyl methacrylate, 2-ethylhexyl methacrylate, isobornyl methacrylate, benzyl methacrylate, phenyl methacrylate, 2-methacryloyloxyethyl succinic acid, 2-hydroxyethyl methacrylate, 2-
Examples thereof include hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, fumaric acid and esters thereof, methacrylonitrile, N, N-dimethylacrylamide, N-vinyl-2-pyrrolidone and the like.

Further, as a crosslinking agent, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth)
Acrylate, propylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, 1,4-butanediol di (meth) acrylate,
It is also possible to use polyfunctional monomers such as 1,6-hexanediol di (meth) acrylate, glycerin di (meth) acrylate, divinylbenzene diallyl phthalate, and diethylene glycol bisallyl carbonate.

The characteristics of these polymerizable monomers used,
That is, it is necessary to select a suitable polymerization method, type of polymerization initiator, addition amount, etc. in consideration of viscosity, volumetric shrinkage rate, polymerization rate and the like.

[0036]

A resin mold for manufacturing a contact lens and a method of manufacturing a contact lens using the same according to the present invention are carried out by a blank mold method by thermosetting. A high quality contact with a smooth surface and edge that does not damage the cornea because it is a resin that can withstand enough and that can be machined with a lathe is used, which has excellent optical and mechanical strength. The lens can be manufactured at low cost.

[0037]

[Examples] The present invention will be described in more detail with reference to the following examples.
The present invention is not limited to these.

Example 1 In this example, as a male material shown in FIG. 1, an ethylene-vinyl alcohol copolymer (trade name Solite M: Nippon Synthetic Chemical Industry Co., Ltd.) was used.
Resin mold manufactured by injection molding with the BC optical surface having a curvature of 7.21 mm, the female die shown in FIG. 2 using polypropylene, and the FC forming surface having a curvature of 7.2 mm. It was used. The thickness of the cavity formed when the male mold and the female mold are combined is 0.
It was set to 5 mm. As the polymerizable monomer, 70 parts by weight of 2,3-dihydroxypropyl methacrylate, 28 parts by weight of methyl methacrylate, 1 part by weight of ethylene glycol dimethacrylate, and 0.2 parts by weight of azobis (2,4-dimethylvaleronitrile) were mixed well. This mixture was used after deaeration and nitrogen replacement. The above resin mold was filled with this mixture, which was placed in a hot air circulation type constant temperature bath and heated at 50 ° C. for 5 hours and at 80 ° C. for 5 hours. Further, for annealing, the male mold with the female mold removed was placed in a hot air circulation type annealing furnace and heated at 125 ° C. for 5 hours.
After that, the male die to which the semi-finished lens was adhered was mounted on a lathe for lens cutting, the FC side of the lens was cut with a curvature of 7.70 mm, and the FC side surface was polished. Further, the outer peripheral defining portion of the lens was cut so as to have a smooth curved shape to form an edge portion. At this time, the cutting tool of a lathe for lens cutting was cut to the surface of the male mold. The obtained contact lens was swollen in pure water, washed, and then immersed in physiological saline to absorb a predetermined amount of water, and at the same time, elution of the eluate was completed.

The soft contact lens thus obtained had smooth surfaces and edges, and there were no voids on the surface or inside of the contact lens. The BC of this soft contact lens is 8.60 mm and the power is -3.00.
It had D, and the optical performance was very excellent. Further, regarding the mechanical strength, an average breaking strength of 192 g and an average elongation of 27
It was 5%, and had a strength equal to or higher than that of a lens manufactured by a lace cut method using a bar material.

The strength of the soft contact lens was evaluated by the following method.

Water-containing soft contact lens with physiological saline (thickness varies depending on the frequency, but 0.03 mm to
0.1 mm) is used as a test piece, and this test piece is stretched in physiological saline at 8 mm intervals with the upper and lower ends sandwiched, and the load at break (breaking strength) and the distance between the fulcrums at that time ( Elongation) was measured, and the average breaking strength and the average elongation were determined from the measured values.

Example 2 In this example, polyacetal (trade name: DURACON M90-44: manufactured by Polyplastics Co., Ltd.) was used as the material of the male mold shown in FIG. 1, and the curvature of the BC optical surface was changed. The resin mold was 7.25 mm, polypropylene was used as the material of the female mold shown in FIG. 2, and the curvature of the FC formation surface was 7.2 mm. The thickness of the cavity formed when the male mold and the female mold were combined was 0.3 mm. As the polymerizable monomer, 97 parts by weight of 2-hydroxyethyl methacrylate, 2 parts by weight of ethylene glycol dimethacrylate, and 0.3 parts by weight of azobis (2,4-dimethylvaleronitrile) were mixed well, and the mixture was degassed, nitrogen-containing. The one with substitution was used. The above resin mold was filled with this mixture, and the mixture was put into a hot air circulation type constant temperature bath and heated at 40 ° C. for 8 hours and at 80 ° C. for 5 hours. After curing, the female mold was removed from the male mold, and the male mold to which the semi-finished lens was adhered was mounted on a lathe for lens cutting, the FC side of the lens was cut with a curvature of 7.70 mm, and the FC side surface was polished.
Further, the outer peripheral defining portion of the lens was cut so as to have a smooth curved shape to form an edge portion. At this time, the cutting tool of a lathe for lens cutting was cut to the surface of the male mold. The obtained contact lens was swollen in pure water, washed, and then immersed in physiological saline to absorb a predetermined amount of water, and at the same time, elution of the eluate was completed.

The soft contact lens thus obtained had smooth surfaces and edges, and there were no voids on the surface or inside of the contact lens. The BC of this soft contact lens is 8.60 mm and the power is -3.00.
It had D, and the optical performance was very excellent. Further, regarding mechanical strength, an average breaking strength of 122 g and an average elongation of 32
It was 5%, and had a strength equal to or higher than that of a lens manufactured by a lace cut method using a bar material.

(Example 3) In this example, an ethylene-vinyl alcohol copolymer (trade name Soalite M: Nippon Synthetic Chemical Industry Co., Ltd.) was used as the male material shown in FIG.
Resin mold manufactured by injection molding with the BC optical surface having a curvature of 6.60 mm, the polypropylene used as the female material shown in FIG. 2, and the FC forming surface having a curvature of 6.5 mm. It was used. The thickness of the cavity formed when the male mold and the female mold are combined is 0.
It was set to 5 mm. As the polymerizable monomer, N, N-dimethylacrylamide 58 parts by weight, 2,2,2-trifluoroethyl methacrylate 25 parts by weight, tris (trimethylsiloxy) silylpropyl methacrylate 10 parts by weight, 2,3-dihydroxypropyl methacrylate 5 1 part by weight of ethylene glycol dimethacrylate and 0.5 part by weight of t-butylperoxypivalate were mixed well, and the mixture was deaerated and replaced with nitrogen. The above resin mold was filled with this mixture, and the mixture was put into a hot air circulation type constant temperature bath, and the mixture was kept at 40 ° C. for 8 hours for 80 hours.
Heated at ° C for 10 hours. Furthermore, for annealing, the male mold with the female mold removed is placed in a hot air circulation type annealing furnace,
Heated at 130 ° C. for 5 hours. Then, the male die to which the semi-finished lens was adhered was mounted on a lathe for lens cutting, the FC side of the lens was cut with a curvature of 7.06 mm, and the FC side surface was polished. Further, the outer peripheral defining portion of the lens was cut so as to have a smooth curved shape to form an edge portion. At this time, the cutting tool of a lathe for lens cutting was cut to the surface of the male mold. The obtained contact lens was swollen in pure water, washed, and then immersed in physiological saline to absorb a predetermined amount of water, and at the same time, elution of the eluate was completed.

The soft contact lens thus obtained had smooth surfaces and edges, and there were no voids on the surface or inside the contact lens. The BC of this soft contact lens is 8.60 mm and the power is -3.00.
It had D, and the optical performance was very excellent. Further, regarding the mechanical strength, an average breaking strength of 168 g and an average elongation of 38
It was 8%, and had a strength equal to or higher than that of a lens manufactured by a lace cut method using a bar material.

(Embodiment 4) In this embodiment, as a material of the male mold shown in FIG.
4200: manufactured by Mitsui Petrochemical Co., Ltd., the BC optical surface has a curvature of 6.90 mm, and polypropylene is used as the female material shown in FIG. 2, and the FC forming surface has a curvature of 7.2 mm. A resin mold manufactured by injection molding was used as The thickness of the cavity formed when the male mold and the female mold were combined was 1 mm. As the polymerizable monomer, 70 parts by weight of 2,3-dihydroxypropyl methacrylate, 28 parts by weight of methyl methacrylate, 1 part by weight of ethylene glycol dimethacrylate, and 0.2 parts by weight of azobis (2,4-dimethylvaleronitrile) were mixed well. This mixture was used after deaeration and nitrogen replacement. The above resin mold was filled with this mixture, and this was put into a hot-air circulation type constant temperature bath, and the mixture was heated at 50 ° C. for 5 hours to 80 ° C.
Heated at ° C for 5 hours. Further, for annealing, the male mold with the female mold removed was placed in a hot air circulation type annealing furnace, and 1
Heated at 25 ° C. for 5 hours. After this, the male die to which the semi-finished lens was adhered was attached to a lathe for lens cutting, the FC side of the lens was cut with a curvature of 7.65 mm, and the FC side surface was polished. Further, the outer peripheral defining portion of the lens was cut so as to have a smooth curved shape to form an edge portion. On this occasion,
It was carried out by cutting the lens cutting lathe tool to the surface of the male mold. The obtained contact lens was swollen in pure water, washed, and then immersed in physiological saline to absorb a predetermined amount of water, and at the same time, elution of the eluate was completed.

The soft contact lens thus obtained had smooth surfaces and edges, and there were no voids on the surface or inside of the contact lens. The BC of this soft contact lens is 8.20 mm and the power is -8.00.
It had D, and the optical performance was very excellent. Further, regarding the mechanical strength, an average breaking strength of 186 g and an average elongation of 26
It was 3%, and had a strength equal to or higher than that of a lens manufactured by a race cut method using a bar material.

Example 5 In this example, a modified polyolefin (trade name ZE) was used as the male material shown in FIG.
ONEX280: used by Nippon Zeon Co., Ltd., BC
The optical surface had a curvature of 7.25 mm, polypropylene was used as the material of the female mold shown in FIG. 2, and the FC forming surface had a curvature of 7.2 mm. A resin mold manufactured by injection molding was used. The thickness of the cavity formed when the male mold and the female mold were combined was 0.3 mm. In addition,
The male mold used here was subjected to plasma treatment. As a plasma treatment method, the male mold was placed in a plasma apparatus, and the treatment was performed in an argon atmosphere with a vacuum degree of 0.1 Torr at a discharge frequency of 13.56 MHz and a discharge power of 200 W for 3 minutes. As the polymerizable monomer, 97 parts by weight of 2-hydroxyethyl methacrylate, 2 parts by weight of ethylene glycol dimethacrylate, and 0.3 parts by weight of azobis (2,4-dimethylvaleronitrile) were mixed well, and the mixture was degassed, nitrogen-containing. The one with substitution was used. The above resin mold was filled with this mixture, and the mixture was put into a hot air circulation type constant temperature bath and heated at 40 ° C. for 8 hours and at 80 ° C. for 5 hours. After curing, the female mold was removed from the male mold, and the male mold to which the semi-finished lens was adhered was mounted on a lathe for lens cutting, the FC side of the lens was cut with a curvature of 7.70 mm, and the FC side surface was polished. Further, the outer peripheral defining portion of the lens was cut so as to have a smooth curved shape to form an edge portion. At this time, the cutting tool of a lathe for lens cutting was cut to the surface of the male mold. The obtained contact lens was swollen in pure water, washed, and then immersed in physiological saline to absorb a predetermined amount of water, and at the same time, elution of the eluate was completed.

The soft contact lens thus obtained had smooth surfaces and edges, and there were no voids on the surface or inside of the contact lens. The BC of this soft contact lens is 8.60 mm and the power is -3.00.
It had D, and the optical performance was very excellent. Further, regarding the mechanical strength, an average breaking strength of 128 g and an average elongation of 33
It was 8%, and had a strength equal to or higher than that of a lens manufactured by a lace cut method using a bar material.

Example 6 In this example, an ethylene-vinyl alcohol copolymer (trade name Soalite M: Nippon Synthetic Chemical Industry Co., Ltd.) was used as the male material shown in FIG.
Resin mold manufactured by injection molding with the BC optical surface having a curvature of 6.60 mm, the polypropylene used as the female material shown in FIG. 2, and the FC forming surface having a curvature of 6.5 mm. It was used. The thickness of the cavity formed when the male mold and the female mold are combined is 0.
It was set to 5 mm. As the polymerizable monomer, N, N-dimethylacrylamide 58 parts by weight, 2,2,2-trifluoroethyl methacrylate 25 parts by weight, tris (trimethylsiloxy) silylpropyl methacrylate 10 parts by weight, 2,3-dihydroxypropyl methacrylate 5 1 part by weight of ethylene glycol dimethacrylate and 0.5 part by weight of t-butylperoxypivalate were mixed well, and the mixture was deaerated and replaced with nitrogen. The above resin mold was filled with this mixture, and the mixture was put into a hot air circulation type constant temperature bath, and the mixture was kept at 40 ° C. for 8 hours for 80 hours.
Heated at ° C for 10 hours. Furthermore, for annealing, the male mold with the female mold removed is placed in a hot air circulation type annealing furnace,
Heated at 130 ° C. for 5 hours. Then, the male die to which the semi-finished lens was adhered was mounted on a lathe for lens cutting, the FC side of the lens was cut with a curvature of 7.06 mm, and the FC side surface was polished. Further, the outer peripheral defining portion of the lens was cut so as to have a smooth curved shape to form an edge portion. At this time, the cutting tool of a lathe for lens cutting was cut to the surface of the male mold. The obtained contact lens was released from the mold in a dry state, and this lens was subjected to plasma treatment. As a plasma treatment method, a contact lens in a dry state is installed in a plasma device and a vacuum degree of 0.
Discharge frequency 13.56M in oxygen atmosphere of 02 Torr
Processing was performed for 5 minutes at 100 Hz and discharge power of 100 W. This was swollen in pure water, washed, and then immersed in physiological saline to absorb a predetermined amount of water, and at the same time, elution of the eluate was completed.

The soft contact lens thus obtained had smooth surfaces and edges, and there were no voids on the surface or inside the contact lens. The BC of this soft contact lens is 8.60 mm and the power is -3.00.
It had D, and the optical performance and the wettability of the lens surface were very excellent. Further, regarding the mechanical strength, the average breaking strength was 156 g and the average elongation was 363%, and the mechanical strength was equal to or higher than that of a lens manufactured by a race cut method using a bar material.

Example 7 In this example, polybutylene terephthalate (trade name Toughpet PBT-N1000: manufactured by Mitsubishi Rayon Co., Ltd.) was used as the male material shown in FIG. 1, and the curvature of the BC optical surface was used. Was 6.60 mm, polypropylene was used as the material of the female mold shown in FIG. 2, and the resin mold manufactured by injection molding was used with the curvature of the FC forming surface being 6.5 mm. The thickness of the cavity formed when the male mold and the female mold were combined was 0.5 mm. As the polymerizable monomer, N, N-
Dimethyl acrylamide 58 parts by weight, 2,2,2-trifluoroethyl methacrylate 25 parts by weight, tris (trimethylsiloxy) silylpropyl methacrylate 10
Parts by weight, 2,3-dihydroxypropyl methacrylate 5 parts by weight, ethylene glycol dimethacrylate 1 part by weight, and t-butyl peroxypivalate 0.5 part by weight were mixed well, and the mixture was deaerated and replaced with nitrogen. I used the one. The above resin mold was filled with this mixture, and the mixture was put into a hot air circulation type constant temperature bath, and the mixture was kept at 40 ° C. for 8 hours for 8 hours.
Heated at 0 ° C. for 10 hours. Furthermore, for annealing, the male mold with the female mold removed was placed in a hot air circulation type annealing furnace and heated at 130 ° C. for 5 hours. Then, the male die to which the semi-finished lens was adhered was mounted on a lathe for lens cutting, the FC side of the lens was cut with a curvature of 7.06 mm, and the FC side surface was polished. Further, the outer peripheral defining portion of the lens was cut so as to have a smooth curved shape to form an edge portion. At this time, the cutting tool of a lathe for lens cutting was cut to the surface of the male mold. The obtained contact lens was swollen in pure water, washed, and then immersed in physiological saline to absorb a predetermined amount of water, and at the same time, elution of the eluate was completed.

The soft contact lens thus obtained had smooth surfaces and edges, and there were no voids on the surface or inside of the contact lens. The BC of this soft contact lens is 8.60 mm and the power is -3.00.
It had D, and the optical performance was very excellent. Further, regarding the mechanical strength, an average breaking strength of 178 g and an average elongation of 40
It was 0%, and had a strength equal to or higher than that of a lens manufactured by a lace cut method using a bar material.

Comparative Example 1 In this comparative example, a contact lens was obtained in the same manner as in Example 1 except that polypropylene was used as the male material shown in FIG. After swelling in pure water and washing in the same manner as in Example 1, it was immersed in physiological saline to absorb a predetermined amount of water, and at the same time, elution of the eluate was completed.

The soft contact lens thus obtained was inferior in surface accuracy to the contact lens obtained in Example 1 and had insufficient optical performance.

(Comparative Example 2) In this comparative example, contact was performed in the same manner as in Example 1 except that the thickness of the cavity formed when the male mold and the female mold were combined was set to 0.1 mm. Got the lens. After swelling in pure water and washing in the same manner as in Example 1, it was immersed in physiological saline to absorb a predetermined amount of water, and at the same time, elution of the eluate was completed.

The soft contact lens thus obtained had a polymerization distortion, and its optical performance was insufficient as compared with the contact lens obtained in Example 1. Further, regarding the mechanical strength, an average breaking strength of 112 g and an average elongation of 2
It was 25%, which was lower than the strength of the contact lens obtained in Example 1.

[0058]

According to the first and fifth aspects of the present invention, the resin mold for producing a contact lens and the method for producing a contact lens using the resin mold are carried out by a blank mold method by thermosetting and used. As the material of the resin mold, it is a resin that can withstand heat curing and heat annealing sufficiently, and because it uses a resin that can be machined with a lathe, it has excellent optical properties and a smooth surface that does not damage the cornea. High quality contact lenses having edges and edges can be manufactured at low cost.

According to the inventions of claims 2 and 6,
The resin mold for manufacturing a contact lens and the method for manufacturing a contact lens using the resin mold have a polymerization distortion due to the thickness of the space formed when the resin mold is combined with the male mold and the female mold being set to 0.3 mm or more. A high-quality contact lens that is suppressed and has excellent optical properties and mechanical strength can be manufactured at low cost.

[Brief description of drawings]

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

FIG. 2 is a sectional view of a female mold for manufacturing a contact lens used in Example 1 of the present invention.

FIG. 3 is an assembled sectional view of a resin mold for manufacturing a contact lens used in Example 1 of the present invention.

[Explanation of symbols]

 1 BC optical surface 2 Male contact surface 3 Attachment when mounted on lathe 4 FC forming surface 5 Female contact surface 6 Side contact surface of mold 7 Lens-shaped space 8 Cavity thickness

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B29C 71/02 2126-4F G02C 7/04 // B29K 23:00 29:00 59:00 67: 00 77:00 81:00 B29L 11:00

Claims (8)

[Claims] 1. A space is formed when a male mold and a female mold are combined with a polymerizable monomer, and the polymerizable monomer is heated to polymerize the monomer. This mold is used in the method of manufacturing a contact lens by attaching the male mold to the lens cutting lathe with it removed, and cutting the front curve side of the lens to produce a contact lens. A resin mold for manufacturing a contact lens, which is a resin that can withstand sufficiently and is made of a resin that can be cut by a lathe. 2. A polymerizable monomer is filled in a space formed when a male mold and a female mold are combined, and the mixture is heated to polymerize it. It is a mold used in the method of manufacturing a contact lens by attaching the male mold to the lathe for lens cutting in the removed state and cutting the front curve side of the lens, and combining this resin mold male mold and female mold A resin mold for manufacturing a contact lens, wherein the thickness of the space formed at this time is 0.3 mm or more. 3. The resin mold for producing a contact lens according to claim 1, wherein the material of the resin mold is a resin that can be molded by injection molding. 4. The resin-type material comprises a resin selected from polyamide, ethylene-vinyl alcohol copolymer, polyacetal, polyester, polysulfone, and amorphous polyolefin. A resin mold for manufacturing a contact lens according to any one of the items. 5. The resin mold material is a resin that can withstand heat curing and heat annealing sufficiently, and is made of a resin that can be machined by a lathe. The male mold and the female mold are combined, and a space is formed between them. After filling the polymerizable monomer and polymerizing it by heating it, attach the male mold to the lens cutting lathe with both molds matched or with the female mold removed, and attach the front curve side of the lens. A method for manufacturing a contact lens, which comprises cutting. 6. A male mold and a female mold are combined so that the thickness of the space formed is 0.3 mm or more, the space formed between them is filled with a polymerizable monomer, and this is heated. A contact lens characterized by mounting the male mold on the lathe for lens cutting after the two molds are overlapped with each other or with the female mold removed and cutting the front curve side of the lens. Manufacturing method. 7. The method of manufacturing a contact lens according to claim 5, wherein the material of the resin mold is a resin that can be molded by injection molding. 8. A resin-type material comprising a resin selected from polyamide, ethylene-vinyl alcohol copolymer, polyacetal, polyester, polysulfone, and amorphous polyolefin. The method for manufacturing a contact lens according to any one of claims.