JPH05100101A - Resin for molding lens and spectacle lens produced by using this resin - Google Patents

Abstract

PURPOSE:To obtain the resin for molding the lens having excellent polishing and grinding properties by irradiating thermoplastic resins, such as polymethyl methacrylate resin or polystyrene resin with a prescribed quantity of ionizable radiations. CONSTITUTION:At least one of the thermoplastic resins among the polymethyl methacrylate(PMMA) resin, the polystyrene(PS) resin and polycarbonate(PC) are irradiated with the prescribed quantity of the ionizable radiations by which the polishing and grinding properties are imparted thereto. Resins formed by copolymerizing ethyl acrylate, butyl methacrylate, etc., with methyl methacrylate as self-polymerizable plastic are used for the PMMA resin in such a case. Resins formed by copolymerizing methyl methacrylate, ethyl acrylate, etc., with styrene are used for the PS resin. Further, alpha rays, beta rays, gamma rays, and electron rays (electron beams) are used as the ionizable radiations with which the resins are to be irradiated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens molding resin such as polymethylmethacrylate resin, polystyrene resin and polycarbonate, and an eyeglass lens manufactured by the resin.

[0002]

2. Description of the Related Art In recent years, in place of conventional glass lenses,
It is well known that spectacle lenses made of plastic have been developed for the purpose of weight reduction, impact resistance, and improvement of safety of lenses. There are two types of methods for manufacturing the above-mentioned plastic spectacle lenses: a method using a casting mold and an injection molding method. The former casting method is a method in which monomers such as ethylene glycol bisallyl carbonate (so-called CR-39 resin), urethanized polyacrylate, and polyol polyacrylate are injected into a casting mold and polymerized one by one. is there. The latter injection molding method uses polymethymethacrylate.
ylmethacrylate, hereinafter simply referred to as PMMA) -based resin, polystyrene (hereinafter simply referred to as PS) -based resin, and polycarbonate (Polycarbonate)
(Hereinafter, simply abbreviated as PC), etc., is used to perform injection molding of a thermoplastic resin molding material using an injection molding die.

[0003]

However, any of the above-mentioned methods has the following various problems. That is, in the former casting method, while it is possible to obtain a spectacle lens having a predetermined shape, on the other hand, it takes more than 10 hours to complete the cross-linking polymerization from the casting of the cross-linking polymerization type resin into the mold. It is necessary to prepare a mold for the casting, and it is usual to add various additives to the above-mentioned casting resin. Therefore, the surface of the mold is easily soiled, and complicated cleaning is required for the casting mold. However, there is a problem in that the power and shape of the manufactured spectacle lens may change due to aging. On the other hand, the latter injection molding method has less contamination of the molding die,
Besides, it has the advantage that the molding time can be shortened and the change over time can be minimized.However, since the resin currently used is sticky, the lens raw material as a resin molded product is ground and polished by post-processing. There is a problem in that the above-mentioned grinding and polishing processes are extremely difficult when the spectacle lens has a shape suitable for the spectacle frame and a predetermined power.

Incidentally, the spectacle lens made of plastics is
Various lenses for nearsightedness, farsightedness, and presbyopia and differences in power,
Although it is originally required to prepare a huge number of types of spectacle lenses depending on the presence or absence of astigmatism, it is practically impossible to prepare a casting mold and an injection mold corresponding to these various lenses. Therefore, prepare a typical basic lens raw material in advance, grind and polish the basic lens raw material according to the request, and make it match the frequency etc. At present, a method of grinding to form a shape that fits the spectacle frame is used.

[0005]

An object of the present invention (first invention) is to provide a resin for molding a lens which is excellent in abrasiveness and grindability.

The invention according to claim 2 of the present invention (the second invention) has an object to provide a spectacle lens which has good optical performance, has very little change over time, and is excellent in polishability and grindability.

[0007]

The invention according to claim 1 (first invention) of the present invention is a PMMA resin, a PS resin,
And a resin for molding a lens in which at least one thermoplastic resin of PC is irradiated with a predetermined amount of ionizing radiation to impart polishing property and grindability.

According to a second aspect of the present invention (the second invention), a molding material made of at least one thermoplastic resin such as PMMA resin, PS resin and PC is irradiated with a predetermined amount of ionizing radiation. , A lens material molded by an injection molding method with the molding material irradiated with the ionizing radiation,
Also, one of the lens raw material that has been subjected to ionizing radiation treatment in which a predetermined amount of ionizing radiation has been irradiated to the lens raw material that has been injection-molded with the molding material made of the above-mentioned thermoplastic resin is ground and ground, and a spectacle frame is obtained. It is a spectacle lens having a shape conforming to.

The resin used for carrying out the present invention is a resin having excellent optical characteristics, such as PMMA resin and PS.
A thermoplastic resin such as a system resin or PC is used. PM mentioned above
MA-based resins include methyl methacrylate as a self-polymerizable plastic, ethyl acrylate, butyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, styrene (C
8 H8), polyalkylene glycol, poly (meth) acrylate, phenylmaleimide, cyclohexylmaleimide, acrylonitrile (CH2 = C)
H-CN, vinyl cyanide) or the like is used.

The PS-based resin described above includes styrene (stylen
e, C8H8) obtained by copolymerizing methyl methacrylate, ethyl acrylate, butyl methacrylate, phenyl methacrylate, cyclohexyl methacrylate, acrylonitrile (CH2 = CH-CN) or the like.

The above-mentioned PMMA resin, PS resin, PC
The ionizing radiation for irradiating the molding material consisting of or the ionizing radiation for irradiating the lens material injection-molded using the above-mentioned thermoplastic resin is α ray, β ray, γ
Ray, electron beam (electron beam) is used.

The irradiation dose is 1 to 200 Mrad (however,
1rad = 10 ^-2 Gy) It is preferably within the range of ^{2 to} 100 Mrad. That is, when the irradiation dose is less than 2 Mrad,
Since the amount of charged particles is too small, it is difficult to obtain a lens molding resin or a lens base material having good polishing and grinding properties. On the other hand, when the irradiation dose exceeds 200 Mrad, Since the amount is too large, the grindability and grindability of the lens molding resin or the lens original material are good, but the mechanical properties of the lens molding resin or the lens original material are deteriorated.

When the resin for molding a lens or the lens base material is colored by yellowing due to the above-mentioned irradiation with ionizing radiation, the heat deformation temperature of the resin is minus 10 ° C. to about 2-3. The coloring (yellowing) described above can be removed by applying heat treatment such as time and hot air drying, but an appropriate irradiation dose of ionizing radiation is the type of the resin used, the thickness of the resin, Considering the decrease in coloration of the resulting lens molding resin or lens base material, 1 to 200 Mr
It is desirable to set it within the range of ad.

To irradiate the above-mentioned molding material before injection molding with ionizing radiation, the molding material is placed in an irradiation treatment container for processing, or the molding material is placed on a belt conveyor and ionized. It is transferred into a radiation irradiation atmosphere so that the irradiation dose is 1 to 200 Mrad.

In order to irradiate the lens original material after the above injection molding with the ionizing radiation, the lens original material is transferred into the ionizing radiation irradiation atmosphere in the same manner as described above, and the irradiation dose is 1.
Try to be ~ 200 Mrad.

The above-mentioned PMMA resin, PS resin, PC
The lens-molding resin formed by irradiating 1 to 200 Mrad of ionizing radiation had extremely good abrasiveness and grindability due to the ionization action of charged particles.

In addition, the above-mentioned PMMA-based resin, PS-based resin, and PC molding materials may be used in a range of 1
After injection of 200 Mrad of ionizing radiation, injection molding of the original lens body, or the above-mentioned PMMA resin, PS
A lens raw material injection-molded with a molding material made of a base resin and PC, which is irradiated with ionizing radiation of 1 to 200 Mrad, has extremely good abrasiveness, grindability, and machinability. Since the grindstone and the pad for polishing the lens did not cause any clogging, it was possible to obtain a spectacle lens having good optical performance and having very little change over time.

[0018]

According to the invention described in claim 1 (first invention) of the present invention, the above-mentioned PMMA-based resin, PS-based resin and PC have α-ray (α-ray) and β-ray (β-ray). , Γ
Radiation of rays (γ-ray) and electron rays (el)
ectron beam) and other ionizing radiation
When n) is irradiated in a predetermined amount, there is an effect that good abrasiveness and grindability can be imparted to the above-mentioned thermoplastic resins.

According to the second aspect of the present invention (the second invention), the above-mentioned PMMA resin, PS resin, P
After irradiating the molding material made of C with a predetermined amount of ionizing radiation before injection molding, the lens raw material is injection-molded, or the molding material made of the above-mentioned PMMA-based resin, PS-based resin, PC is used. When a predetermined amount of ionizing radiation is irradiated to the lens original material injection-molded using the above α ray, β
Due to the ionizing action of the charged particles of the rays, γ rays and electron rays, the above-mentioned lens raw material is provided with good polishing and grindability. As a result, there is an effect that it is possible to obtain a spectacle lens which has good optical performance, has very little change with time, and is excellent in polishability and grindability.

[0020]

[Embodiment 1] Hereinafter, an embodiment of the present invention will be described in more detail. In order to compare the lens processability of this example with the lens processability of the conventional product, resin pellets of PMMA, PS, and PC were irradiated with electron beams of the respective doses shown in Table 1 below. With those that do not irradiate any electron beam,
The lens raw material was injection-molded, and the polishing properties and grindability of the lens raw material after injection molding were compared by the time required for processing.

[0021]

[Table 1]

In the above Table 1, the grindability indicates the time for shaping the eyeglass lens using the diamond grindstone, the roughing indicates the time for grinding using the electrodeposited diamond foil, and the intermediate finishing uses gold sand. The polishing processing time is shown, and the finishing processing is the time required for the polishing finishing processing.

As is apparent from Table 1 above, the processability of the lens injection-molded with the resin obtained by electron beam irradiation of this example is excellent in grindability and polishability, but the electron beam irradiation is performed. As for the workability of conventional lenses injection-molded with a non-resin, not only grinding becomes impossible due to clogging of a diamond grindstone, but also polishing is poor.

[0024]

[Example 2] In order to compare the lens processability of this example with the lens processability of a conventional product, PMMA was used to obtain a diameter of 78.
mmφ, thickness 9 mm, radius of curvature of front of lens is 87 mm, radius of curvature of rear of lens is 96 mm, injection molding is performed, and this prototype is irradiated with electron beam. Grinding and polishing are performed on the equivalent product of the conventional example that does not irradiate the electron beam, and the power is +4 diopters, the radius of curvature of the lens front surface is 87 mm, the radius of curvature of the lens rear surface is 288 mm, the edge thickness is 1 mm, and the center thickness is 7.6 mm Table 2 below shows the results of comparison of the grindability and the grindability in the time required for the grinding and the grinding described above after forming the meniscus lens for spectacles.

[0025]

[Table 2]

As is clear from Table 2 above, the processability of the lens obtained by irradiating the original lens body after injection molding with an electron beam in this example is excellent in grindability and polishability. As for the workability of the conventional lens in which the original material of the lens is not irradiated with the electron beam, not only the grinding becomes impossible due to the clogging of the diamond grindstone, but also the polishing property is poor.

Claims (2)

[Claims] 1. A lens molding characterized in that at least one thermoplastic resin of polymethylmethacrylate resin, polystyrene resin, and polycarbonate is irradiated with a predetermined amount of ionizing radiation to impart abrasiveness and grindability. Resin. 2. At least one of a polymethylmethacrylate resin, a polystyrene resin, and a polycarbonate.
A molding material composed of two thermoplastic resins is irradiated with a predetermined amount of ionizing radiation, and a lens material molded by an injection molding method with the molding material irradiated with the ionizing radiation, and a molding material composed of the thermoplastic resin. It is characterized by polishing and grinding one of the lens original material injection-molded in 1. with the ionizing radiation-treated lens original material that is irradiated with a predetermined amount of ionizing radiation to a shape that fits the eyeglass frame. And eyeglass lenses.