JP2013213935A - Method for manufacturing plastic lens for spectacles - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide means for providing a high-quality plastic lens for spectacles suppressing an occurrence of orange peel.SOLUTION: The method for manufacturing a plastic lens for spectacles provides a plurality of plastic lenses for spectacles by performing the following manufacturing process a plurality of times. The manufacturing process includes the steps of: injecting a plastic lens raw material liquid containing a curable component into a cavity of a molding die that has two molds facing each other at a prescribed interval, and the cavity formed by closing the interval; performing hardening reaction of the plastic lens raw material liquid in the cavity to acquire a plastic lens; demolding the acquired plastic lens from the molding die; and treating the demolded plastic lens by heat. The plastic lens after the demolding includes a lens the surface hardness of which has Rockwell hardness of 100 or less on the R scale. A maximum temperature in the heat treatment is set lower as the surface hardness of the plastic lens after the demolding becomes lower.

Description

  The present invention relates to a method for manufacturing a plastic lens for spectacles, and more particularly to a method for manufacturing a plastic lens for spectacles that can provide a high-quality plastic lens with few surface defects by casting polymerization.

  Plastics are widely used as a material for eyeglass lenses because they have the advantage of being lighter and harder to break than glass. Examples of a method for obtaining a plastic lens by molding plastic into a lens shape include a casting polymerization method in which a plastic lens raw material liquid is polymerized in a mold.

  Among eyeglass lenses, what is called a photochromic lens, which contains a photoresponsive dye (photochromic compound), can develop color in bright outdoors and restore high transparency when moved indoors. An anti-glare effect similar to that of a color lens having a density can be exhibited. As a method for producing a photochromic lens, in addition to a method for obtaining a plastic lens (lens substrate) containing a photochromic compound using the casting polymerization method (see Patent Documents 1 and 2), a lens substrate was molded. A method of performing a photochromic performance imparting process such as a coating process later (see Patent Documents 3 and 4) has also been proposed. The former method is preferable as a production method because it can obtain a plastic lens having photochromic performance without separately carrying out the photochromic performance imparting step, and has fewer manufacturing steps than the latter method. In addition, there are various advantages not found in the latter method, such as the ability to easily obtain a photochromic lens exhibiting a high color density. In addition to the above, as a method for producing a photochromic lens, a method for obtaining a photochromic lens provided with a coating film (photochromic film) containing a photochromic compound by casting polymerization has been proposed (see Patent Document 5).

JP-A-5-34649 JP-A-8-169923 JP-A-61-2228402 Japanese Patent Laid-Open No. 62-10604 WO2008 / 001578A1

  Patent Document 5 shows that as the object-side surface of the photochromic film becomes more flexible, the photochromic compound becomes easier to move in response to light, and as a result, the response speed and color density of the photochromic lens are greatly improved. ing. As a result of the inventor's investigation, this point is also applicable to a photochromic lens containing a photochromic compound in a plastic lens obtained by the method described in Patent Documents 1 and 2, and adjustment of the composition of the lens raw material and curing conditions It has been clarified that by reducing the surface hardness of the plastic lens molded by the above, a photochromic lens that responds quickly to light and develops color at a high density can be obtained. However, at the same time, as a result of the inventor's investigation, in a plastic lens with a reduced surface hardness, minute dot-like irregular deformation (so-called orange peel) occurs particularly noticeably on the lens surface, and has an appearance that can withstand practical use as a spectacle lens. It also proved difficult to obtain a lens.

  Accordingly, an object of the present invention is to provide means for obtaining a high-quality plastic lens for spectacles in which the occurrence of orange peel is suppressed. More specifically, even if the surface is a relatively soft lens, the orange peel To provide a method of manufacturing a plastic lens for spectacles capable of reducing the occurrence of

As a result of intensive studies to achieve the above object, the present inventor has obtained the following new knowledge.
In the manufacturing method of the plastic lens for spectacles using the casting polymerization method, the plastic lens released from the mold is usually subjected to heat treatment for annealing, functional film curing treatment, and the like. The present inventor has produced a plastic lens with a reduced surface hardness for the reasons described above, and orange peel was noticeably generated after the heat treatment. Therefore, the surface hardness obtained using the casting polymerization method is low, that is, the surface Considering that the cause of the orange peel in soft plastic glasses for glasses is due to the heat treatment, further investigations were made. As a result, it was surprisingly found that a plastic lens having a lower surface hardness cannot prevent the occurrence of orange peel unless the maximum temperature during heat treatment is set lower. Conventionally, there is no knowledge that the heat treatment temperature should be set based on the lens surface hardness, and this knowledge is found for the first time when the present inventor has produced a plastic lens having a lower surface hardness than the conventional one. It has been done.
Regarding the above points, the present inventor has developed a force to cause deformation in the lens surface layer portion when the non-uniform internal strain generated in the lens surface layer portion during polymerization is relieved by heating, and the surface is soft. The lens believes that this force cannot be resisted by lower temperature heating. This means that the softer the lens surface, the smaller the unevenness on the lens surface unless the temperature applied to the lens during heat treatment is set lower. It is presumed that the generation of deformation (orange peel) cannot be sufficiently suppressed. The above-mentioned non-uniform internal distortion occurs when minute foreign matter is mixed in the plastic lens raw material liquid and polymerized while remaining on the lens surface layer part, and the lens surface around the foreign matter may be unevenly deformed by heat treatment. It is thought to be a cause of the occurrence of orange peel. Even if an orange peel has a very small foreign particle as a core of several μm or less, the deformation range may extend to about 300 μm, and it becomes a defect that can be visually recognized by the naked eye. Further, if strain remains in the polymer surface layer part in the polymerization step, the surface may be deformed by stress relaxation during heat treatment even if there are no minute foreign matters, which is considered to cause orange peel.
As a result of further studies based on the above findings, the present inventor has completed the present invention.

That is, the above object was achieved by the following means.
[1] Injecting a plastic lens raw material solution containing a curable component into the cavity of a mold having two molds facing each other with a predetermined interval and a cavity formed by closing the interval,
A plastic lens raw material solution is cured in the cavity to obtain a plastic lens,
Releasing the resulting plastic lens from the mold, and
Heat-treating the released plastic lens,
A method of manufacturing a plastic lens for spectacles to obtain a plurality of plastic lenses for spectacles by performing a manufacturing process including a plurality of times,
The plastic lens after the release includes a lens having a surface hardness of R scale Rockwell hardness of 100 or less, and the maximum temperature in the heat treatment is set to a lower temperature for a plastic lens having a lower surface hardness after the release. A method for producing a plastic lens for spectacles.
[2] Injecting a plastic lens raw material liquid containing a curable component into the cavity of a mold having two molds facing each other with a predetermined interval and a cavity formed by closing the interval,
A plastic lens raw material solution is cured in the cavity to obtain a plastic lens,
Releasing the resulting plastic lens from the mold, and
Heat-treating the released plastic lens,
A method for producing a plastic lens for spectacles, comprising:
The surface hardness of the plastic lens after release is R scale Rockwell hardness of 100 or less, and the maximum temperature in the heat treatment is set based on a predetermined correlation, where the correlation is the surface after release. A method for producing a plastic lens for spectacles, characterized in that a plastic lens having a lower hardness has a lower maximum temperature.
[3] Injecting a plastic lens raw material liquid containing a curable component into the cavity of a mold having two molds facing each other with a predetermined interval and a cavity formed by closing the interval,
A plastic lens raw material solution is cured in the cavity to obtain a plastic lens,
Releasing the resulting plastic lens from the mold, and
Heat-treating the released plastic lens,
A method for producing a plastic lens for spectacles, comprising:
The surface hardness of the plastic lens after the release is R scale Rockwell hardness of 100 or less, and the maximum temperature in the heat treatment is 110 ° C. or less and more than 90 for lenses having an R scale Rockwell hardness of 95 or more and 100 or less. A method for producing a plastic lens for spectacles, wherein the temperature is set to 105 ° C. or lower for lenses less than 95, 100 ° C. or lower for lenses greater than 85 and 90 to 90, and 95 ° C. or lower for lenses below 85.
[4] A plastic lens for spectacles according to any one of [1] to [3], wherein a plastic lens having a photochromic property is obtained by using a plastic lens raw material liquid containing a photochromic compound as the plastic lens raw material liquid. Manufacturing method.

  According to the present invention, it is possible to prevent the occurrence of orange peel in a plastic lens for spectacles obtained by a production method using a casting polymerization method, particularly in a photochromic lens in which the surface hardness is set low in order to obtain high photochromic performance. , It is possible to effectively suppress the occurrence of orange peel that causes quality degradation.

It is a graph which shows the relationship between the surface hardness of the plastic lens obtained in the Example, and the maximum annealing temperature with an orange peel generation rate of 0%. It is a graph which shows the relationship between the surface hardness of the plastic lens obtained in the Example, and the maximum annealing temperature with an orange peel generation rate of 0%.

  According to the present invention, a plastic lens raw material liquid containing a curable component is injected into the cavity of a mold having two molds facing each other with a predetermined interval and a cavity formed by closing the interval. A manufacturing process that includes curing a plastic lens raw material solution in a cavity to obtain a plastic lens, releasing the obtained plastic lens from a mold, and subjecting the released plastic lens to heat treatment. A method of manufacturing a plastic lens for spectacles, wherein a plurality of plastic lenses for spectacles is obtained by performing a plurality of times, and the plastic lens after mold release includes a lens having a surface hardness of R scale Rockwell hardness of 100 or less. The maximum temperature in the heat treatment is included, and the surface hardness after mold release is low. Method for producing a plastic lens for spectacles, which comprises setting a low temperature as ticks lens (hereinafter, referred to as "method 1".) It relates.

  Further, the present invention is to inject a plastic lens raw material liquid containing a curable component into the cavity of a mold having two molds facing each other with a predetermined interval and a cavity formed by closing the interval. For eyeglasses, including obtaining a plastic lens by performing a curing reaction of the plastic lens raw material solution in the cavity, releasing the obtained plastic lens from the mold, and subjecting the released plastic lens to heat treatment A method for producing a plastic lens, wherein the surface hardness of the plastic lens after the release is R scale Rockwell hardness of 100 or less, and the maximum temperature in the heat treatment is set based on a predetermined correlation, The correlation is higher for plastic lenses with lower surface hardness after mold release. The is characterized in that to set a low temperature method of manufacturing a plastic lens for spectacles (hereinafter, referred to as "method 2".) It relates.

All of the above manufacturing methods were found based on the new knowledge by the present inventor that the plastic lens having a lower surface hardness after mold release should be set to a lower temperature in the heat treatment. Therefore, according to the manufacturing method, a high-quality plastic lens for spectacles without an orange peel can be provided. The method 3 described later is also based on the above knowledge.
Hereinafter, the production method of the present invention will be described in more detail. The following description applies to both Method 1 and Method 2, and also to Method 3 described below, unless otherwise specified.

Molding of Plastic Lens by Cast Polymerization In the manufacturing method of the present invention, a curable component is applied to the cavity of a mold having two molds facing each other with a predetermined interval and a cavity formed by closing the interval. A plastic lens raw material liquid is injected, and a plastic lens raw material liquid is cured in the cavity to obtain a plastic lens. The said process can be implemented similarly to the normal casting polymerization method. For details of the mold to be used, reference can be made to paragraphs [0012] to [0014] of JP-A-2009-262480 and FIG.

  As the plastic lens raw material liquid to be injected into the cavity, an appropriate one may be selected and used according to the optical characteristics required for the plastic lens for spectacles to be manufactured. As an example, a plastic lens raw material solution suitable for obtaining a plastic lens containing a photochromic compound according to the present invention will be described.

  As the curable component contained in the plastic lens raw material liquid, it is preferable to use those having radical polymerizability and giving a transparent polymer, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl. (Meth) acrylate, ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, glycidyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, isobornyl (meth) acrylate , Monofunctional (meth) acrylates such as adamantyl (meth) acrylate, α-naphthyl (meth) acrylate, β-naphthyl (meth) acrylate, ethylene glycol di (meth) acrylate, diethyleneglycol Rudi (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, glycerin di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, 2, Polyfunctional (meth) acrylic acid esters such as 2-bis (4- (methacryloxyethoxy) phenyl) propane, styrene, methylstyrene, dimethylstyrene, ethylstyrene, α-methylstyrene, black Styrene, dichlorostyrene, bromostyrene, p-chloromethylstyrene and other nuclear-substituted styrene, 1-vinylnaphthalene, 2-vinylnaphthalene, 4-vinylbiphenyl, vinylphenylsulfide and other vinyl compounds, acrylonitrile, methacrylonitrile, Examples thereof include maleic anhydride, N-substituted maleimide, and allyl compounds such as diethylene glycol bisallyl carbonate and diallyl phthalate. These curable components can be used alone or in combination of two or more. The surface hardness of the molded plastic lens can be controlled by the type of curable component, the mixing ratio, and the like.

  The photochromic compound is not particularly limited as long as it exhibits photochromic performance, and any known compound that can be used for the photochromic lens can be appropriately selected and used. For example, one or a mixture of two or more photochromic compounds such as a spiropyran compound, a chromene compound, a spirooxazine compound, and a fulgide compound can be used depending on the desired coloration.

  Examples of the above spiropyran compounds include indole and spirobenzopyran indole and benzene ring halogens such as halogen, methyl, ethyl, methylene, ethylene, and hydroxyl groups, and indolinospironaphthopyran indole and naphthalene rings. Substituents such as halogen, methyl, ethyl, methylene, ethylene, hydroxyl group, indole ring of indolinospiroquinolinopyran, halogen, methyl, ethyl, methylene, ethylene, hydroxyl group substituents, indolinospiropyropypyran indole Examples of the substituents include ring halogen, methyl, ethyl, methylene, ethylene, hydroxyl group and the like.

  Examples of chromene compounds include spiro [norbornane-2,2 ′-[2H] benzo [h] chromene], spiro [bicyclo [3.3.1] nonane-9,2 ′ [2H] benzo [h]. Chromene], 7'-methoxyspiro [bicyclo [3.3.1] nonane-9,2 '-[2H] benzo [h] chromene], 7'-methoxyspir [norbornane-2,2'-[2H] benzo [F] chromene], 2,2-dimethyl-7-octoxy [2H] benzo [h] chromene, spiro [2-bicyclo [3.3.1] nonene-9,2 '-[2H] benzo [h] Chromene], spiro [2-bicyclo [3.3.1] nonene-9,2 ′-[2H] benzo [f] chromene], 6-morpholino-3,3-bis (3-fluoro-4-methoxyphenyl) ) -3H-benzo (f) chromene, 5-iso Like propyl-2,2-diphenyl -2H- benzo (h) chromene.

  Examples of spirooxazine compounds include halogen, methyl, ethyl, methylene, ethylene, and hydroxyl groups of indolinospirobenzoxazine indole and benzene rings, and indole and naphthalene rings of indinospironaphthoxazine. Substitutes such as halogen, methyl, ethyl, methylene, ethylene, hydroxyl group, indole ring halogen, methyl, ethyl, methylene, ethylene, hydroxyl group, etc. of indolinospirophenanthrooxazine, indinospiroquinolineoxazine Of each indole ring such as halogen, methyl, ethyl, methylene, ethylene, hydroxyl group, piperidinospironaphthoxazine piperidine ring and naphthalene ring halogen, methyl, ethyl, methylene, ethylene, hydroxyl group, etc. Such as substitution products thereof.

Examples of fulgide compounds include N-cyanomethyl-6,7-dihydro-4-methyl-2-phenylspiro (5,6-benzo [b] thiophenedicarboximide-7,2′-tricyclo [3.3 .1.1 ^3,7] decane], N- cyanomethyl-6,7-dihydro-2-(p-methoxyphenyl) -4-methylspiro (5,6-benzo [b] thiophene-dicarboximide -7,2 '-Tricyclo [3.3.1.1 ^3,7 ] decane), 6,7-dihydro-N-methoxycarbonylmethyl-4-methyl-2-phenylspiro (5,6-benzo [b] thiophenedicarboxy Imido-7,2′-tricyclo [3.3.1.1 ^3,7 ] decane), 6,7-dihydro-4-methyl-2- (p-methylphenyl) -N-nitromethylspiro (5 6-Benzo [b] chi Fen-dicarboximide -7,2'- tricyclo [3.3.1.1 ^{3, 7]} decane), N- cyanomethyl-6,7-dihydro-4-cyclopropyl-3- methylspiro (5,6-benzo [B] Thiophenedicarboximide-7,2′-tricyclo [3.3.1.1 ^3,7 ] decane), N-cyanomethyl-6,7-dihydro-4-cyclopropylspiro (5,6-benzo [B] Thiophenedicarboximide-7,2′-tricyclo [3.3.1.1 ^3,7 ] decane), N-cyanomethyl-6,7-dihydro-2- (p-methoxyphenyl) -4- And cyclopropylspiro (5,6-benzo [b] thiophenedicarboximide-7,2′-tricyclo [3.3.1.1 ^3,7 ] decane).

  In recent years, various types of photochromic compounds are commercially available, and in the case of commercially available compounds, the molecular structure is often not clarified, but they can also be used in the present invention.

  The amount of the photochromic compound in the plastic lens raw material liquid may be appropriately set according to the type of the photochromic compound to be used. From the viewpoint of obtaining good photochromic performance, the amount is usually 0.001 with respect to 100 parts by mass of the plastic lens raw material liquid. It is set in the range of -3.0 mass parts, preferably 0.01-1.0 mass parts.

  The plastic lens raw material liquid usually contains a polymerization initiator together with the curable component and the photochromic compound. As the polymerization initiator, an appropriate one is selected and used depending on whether the curing reaction of the curable component is thermal polymerization or photopolymerization. The polymerization initiator that can be used for thermal polymerization will be described. Organic peroxides and azo compounds known as radical generators can be used, and in particular, 2,2′-azobisisobutyronitrile and 2,2 Azo compounds such as' -azobis (2,4-dimethylvaleronitrile), or tert-butyl peroxyneodecanate, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanate, etc. Organic peroxides are preferred because they have little influence on the photochromic compound. A polymerization initiator may be used individually by 1 type, and can also be used in combination of 2 or more type. The amount of the polymerization initiator in the plastic lens raw material liquid is usually in the range of 0.01 to 3.0 parts by mass, preferably 0.05 to 1.5 parts by mass with respect to 100 parts by mass of the plastic lens raw material liquid. .

  If necessary, the plastic lens raw material liquid may further contain various additive components such as a heat stabilizer, an antioxidant, an ultraviolet absorber, a release agent, an antistatic agent, and other dyes.

  The plastic lens raw material liquid can be injected into the mold cavity from the injection port provided on the side surface of the mold, as is usually done in the casting polymerization method. After the injection, the plastic lens raw material liquid is cured (usually radical polymerization) by performing a curing process by heating or light irradiation according to the curable components contained in the plastic lens raw material liquid, and the internal shape of the cavity is transferred. A molded product can be obtained.

  The surface hardness of a plastic lens molded by cast polymerization is also affected by polymerization conditions. When the curing reaction of the plastic lens raw material liquid is thermal polymerization, the heating conditions for polymerization vary depending on the polymerization initiator used, but are usually in the range of 20 to 100 ° C. and in the range of 6 to 48 hours. Furthermore, in order to increase the degree of polymerization of the lens, the reaction temperature may be raised to a region of 100 ° C. or higher as the polymerization reaction proceeds.

  After completion of the curing reaction, the molded body (plastic lens) inside the cavity is released from the mold. As is usually done in the casting polymerization method, the plastic lens can be released from the mold by removing the upper and lower molds forming the cavity and the sealing members such as gaskets in an arbitrary order.

In the present invention, the plastic lens released from the mold is subjected to heat treatment. In method 1, a plurality of plastic lenses are molded by cast polymerization, and the molded lenses include those having different surface hardness, and among these, the surface hardness is R scale Rockwell hardness of 100 or less, A lens with a softer surface than the conventional one is included. In the method 1, the maximum temperature in the heat treatment is set to a lower temperature for a plastic lens having a lower surface hardness for a plurality of plastic lenses after release for the reason described above. The surface hardness here may be measured by preparing a sample lens in advance in a preliminary experiment, and the magnitude relationship of the surface hardness of the plastic lens to be molded can be grasped from the composition of the plastic lens raw material liquid and the polymerization conditions. Is possible. In the present invention, the temperature related to heat treatment refers to the atmospheric temperature at which heat treatment is performed, for example, the temperature inside the heating furnace.

  On the other hand, the lens subjected to the heat treatment in Method 2 is a lens having a surface hardness of 100 or less on the R scale and a soft surface compared to the conventional lens. In Method 2, the lens is separated prior to the actual manufacturing process. Defines the correlation for setting the maximum temperature in the heat treatment applied to the plastic lens after molding. The correlation defined here assumes that the maximum temperature is set to a lower temperature for a plastic lens having a lower surface hardness after mold release for the reason described above. For example, in a preliminary experiment before actual production, a plurality of plastic lenses having different surface hardness after mold release were manufactured, and heat treatment was performed by changing the maximum temperature for these plastic lenses. The presence or absence of an orange peel is determined at. Then, the correspondence between the orange peel occurrence rate and the maximum temperature is confirmed, and the correlation value between the maximum value of the maximum temperature at which the orange peel occurrence rate is equal to or less than the threshold value or the logarithm of the maximum value and the surface hardness is obtained. In the examples described later, an example in which the threshold of the orange peel occurrence rate is 0% is shown. The threshold of the orange peel occurrence rate is most desirably 0% for improving the yield, but is set to a value exceeding 0%, for example, about 10% or 20% within an allowable range from the cost aspect. It is also possible. The above correlation equation can be obtained by a known linear approximation or curve approximation such as a least square method, and the maximum temperature of heat treatment applied to the plastic lens after mold release in the actual production is set as the correlation equation thus obtained. Can be used as a correlation.

In the present invention, the surface hardness of the plastic lens after release is defined by the Rockwell hardness of R scale (hereinafter referred to as “HR”). When the threshold of the orange peel occurrence rate is set to 0% based on the examples described later, the maximum temperature in the heat treatment applied to the plastic lens having a surface hardness after mold release of R scale Rockwell hardness of 100 or less is R scale Rockwell. 110 ° C. or less for lenses having a hardness of 95 or more and 100 or less, 105 ° C. or less for lenses less than 90 and less than 95, 100 ° C. or less for lenses greater than 85 and less than 90 and less than 90, and 95 ° C. or less for lenses of 85 or less Can be set.
That is, according to the present invention, a plastic lens raw material liquid containing a curable component is injected into the cavity of a mold having two molds facing each other with a predetermined interval and a cavity formed by closing the interval. The plastic lens raw material solution is cured in the cavity to obtain a plastic lens, the obtained plastic lens is released from the mold, and the released plastic lens is subjected to heat treatment. A method of manufacturing a plastic lens for spectacles, wherein the plastic lens after mold release has a surface hardness of R scale Rockwell hardness of 100 or less, and the maximum temperature in the heat treatment is R scale Rockwell hardness of 95 or more and 100. For lenses below 110 ° C or lower and over 90 and under 95 For a lens of 105 ° C. or less, 85 to 90 or less and less than 90, the temperature is set to 100 ° C. or less, and for a lens of 85 or less, 95 ° C. or less. Is also provided).

About the plastic lens containing a photochromic compound, it is preferable that the surface hardness of the surface which becomes an object side at the time of use is HR100 or less. This is because the photochromic compound is easy to move in the lens when the object side surface is HR100 or less, so that the photoresponse speed is fast and color can be developed at a high density. Similarly, the surface hardness of the surface on the eyeball side when using the photochromic lens can be HR100 or less. In addition, the plastic lens for spectacles obtained by this invention is not restricted to the plastic lens (photochromic lens) containing a photochromic compound. In addition, the lens subjected to the heat treatment in Method 1 may include a lens having an HR of 100 or less and a lens having an HR of more than HR100.
As described above, in the case of a plastic lens having a soft surface, when no countermeasure is taken, the occurrence of orange peel after heat treatment is particularly noticeable. According to the present invention, the occurrence can be effectively suppressed. Therefore, the methods 1 to 3 are applied as a method for producing a plastic lens for spectacles, which includes obtaining a plastic lens for spectacles by performing heat treatment on a plastic lens having a soft surface after release, that is, an HR of 100 or less. The lower limit of HR is not particularly limited, but is preferably HR 70 or higher from the viewpoint of preventing deformation during use. In the present invention, the Rockwell hardness HR of the R scale means a value measured at 23 ° C. according to JIS K7202-2.

  Examples of the heat treatment applied to the plastic lens after the release include thermal curing treatment of functional films such as annealing and hard coat. In the present invention, as described above, any heat treatment is performed at a lower temperature for a lens having a lower surface hardness. Annealing is usually performed by leaving the lens in a heating furnace at a furnace temperature of about 100 to 150 ° C. for about 1 to 5 hours. The maximum temperature in the furnace for annealing achieves an orange peel rate of 0%. From the point of view, as described above, the lens of HR 95 or more and 100 or less is 110 ° C. or less, the lens of 90 to less than 95 is 105 ° C. or less, the lens of 85 or more and 90 or less and less than 90 is 100 ° C. or less and 85 or less. The lens is preferably set to 95 ° C. or lower.

  Moreover, when the surface of the plastic lens (lens base material) molded by the casting polymerization method is soft, it is preferable to form a hard coat layer in order to enhance scratch resistance and prevent the occurrence of new surface defects. In order to form these coating layers, a method of coating the coating composition on the lens substrate by dipping method, spin coating method, roll coating method, spraying method or the like is usually used. Curing of the applied coating composition is generally performed by heat treatment. Although it depends on the composition of the coating composition, the heating temperature is generally 40 to 150 ° C. (preferably 80 to 130 ° C.) and the heating time is 1 to 4 hours. The maximum temperature during heating is orange peel. From the viewpoint of realizing the occurrence rate of 0%, as described above, the lens of HR 95 to 100 is 110 ° C. or less, the lens of 90 to less than 95 is 105 ° C. or less, and the lens of 85 to 90 to 90 is 100. It is preferable to set it to 95 ° C. or less for lenses having a temperature of 85 ° C. or less.

On the surface of the cured coating obtained as described above, an antireflection film can be formed in order to impart an antireflection effect to the plastic lens for spectacles. The antireflection film is formed of a single dielectric made of a dielectric material such as SiO, SiO ₂ , Si ₃ N ₄ , TiO ₂ , ZrO ₂ , Al ₂ O ₃ , or MgF ₂ by vacuum deposition, ion sputtering, or ion plating. It can be formed by laminating layers or multilayer thin films, and reflection at the interface with the atmosphere can be kept low. When the antireflection film is composed of a single layer, the optical film thickness is preferably λ0 / 4 (λ0 = 450 to 650 nm). Also, a two-layer film having an optical film thickness of λ0 / 4−λ0 / 4 having different refractive indexes, and an optical film thickness of λ0 / 4−λ0 / 2−λ0 / 4 or λ0 / 4−λ0 / 4−λ0 / 4. A multilayer antireflection film composed of a three-layer film having a different refractive index or a multilayer antireflection film partially replaced by an equivalent film is useful.

EXAMPLES Next, although an Example demonstrates this invention still in detail, this invention is not limited to the aspect shown in an Example. In the examples, the methods used for the evaluation of the photochromic performance and the apparatuses used are as follows.
(A) Light transmittance during color development (T% max): Using a xenon lamp (300 W) light source device, the lens is placed for 5 minutes under the conditions of a temperature of 23 ° C. and an ultraviolet intensity of 1.2 mW / cm ² measured with an integrating light meter. The spectrum at the time of color development is measured by an instantaneous multi-photometry system and defined as the light transmittance at the maximum absorption wavelength (λmax) at that time. The lower the light transmittance, the higher the color density.
(B) Fading half-life (F1 / 2): defined as the time required for the absorbance at λmax of the lens to drop to ½ after the light irradiation is stopped after the color development for 5 minutes. The shorter the time, the faster the fading speed.
-Light source: Ushio Electric Co., Ltd. xenon lamp (300W) device “UIT-501C”
・ Integrated light meter: Integrated light meter “UIT-102 (receiver UVD365PD)” manufactured by Ushio Electric Co., Ltd.
-Instant multi-photometry system: "MCPD-3000" manufactured by Otsuka Electronics Co., Ltd.

1. Molding of plastic lens by casting polymerization Five types of plastic lenses having different surface hardness were molded by casting polymerization method by the following method. A plurality of lenses of each type were prepared, and the R scale Rockwell hardness was measured at 23 ° C. according to JIS K7202-2 for the surface hardness measurement lens. The values are shown in Table 1 below.

Casting polymerization of lens type 1 2,2′-bis [4- (methacryloyloxyethoxy) phenyl] propane (m + n = 2.6 in the following structural formula (1), R ¹ is a methyl group, R ² is a hydrogen atom ) 50% by mass, tetraethylene glycol dimethacrylate 30% by mass, tetraethylene glycol diacrylate 10% by mass, α-methylstyrene 8% by mass, 2,4-diphenyl-4-methyl-1-pentene 2% by mass In 100 parts by mass, 0.02 parts by mass of Chromtech Photochromic Dyes PH-4115 as a photochromic compound was dissolved, and 1.0 parts by mass of t-butyl peroxyneodecanate as a polymerization initiator was added and mixed. Each of these preparations is poured into a mold composed of two glass molds and a plastic gasket, and the mold is placed in a hot-air circulating heating furnace and heated at 40 ° C. for 12 hours, and then raised to 85 ° C. over 4 hours. The polymerization was carried out by heating for 2 hours. Thereafter, the mold was released to obtain a highly transparent flat lens having a thickness of 6.0 mm (for surface hardness measurement) or 2.0 mm and an outer diameter of 75 mm.

Casting polymerization of lens type 2 50% by mass of 2,2′-bis [4- (methacryloyloxyethoxy) phenyl] propane used in the monomer mixed solution composition of the photochromic polymerizable composition, and tetraethylene glycol dimethacrylate 30 10% by mass, polyethylene glycol dimethacrylate (in the following formula, B represents an ethylene group, p represents the number of 9 on average), 10% by mass of α-methylstyrene, 2,4-diphenyl-4-methyl- A highly transparent flat lens having a thickness of 6.0 mm (for surface hardness measurement) or 2.0 mm and an outer diameter of 75 mm was obtained in the same manner as in Example 1 except that 1-pentene was changed to 2% by mass.

Casting polymerization of lens type 3 The monomer mixed solution composition of the photochromic polymerizable composition was 50% by mass of 2,2′-bis [4- (methacryloyloxyethoxy) phenyl] propane used in Example 1, tetraethylene glycol di- Example except that 20% by weight of methacrylate, 20% by weight of polyethylene glycol dimethacrylate used in Example 2, 8% by weight of α-methylstyrene, and 2% by weight of 2,4-diphenyl-4-methyl-1-pentene were used. 1 was used to obtain a highly transparent planar lens having a thickness of 6.0 mm (for surface hardness measurement) or 2.0 mm and an outer diameter of 75 mm.

Lens Type 4 Cast Polymerization 2,2′-bis [4- (methacryloyloxyethoxy) phenyl] propane (m + n = 2.6) 50 used in Example 1 for the monomer mixed solution composition of the photochromic polymerizable composition % By mass, 20% by mass of tetraethylene glycol diacrylate, 20% by mass of polyethylene glycol dimethacrylate used in Example 2, 8% by mass of α-methylstyrene, 2% by mass of 2,4-diphenyl-4-methyl-1-pentene A highly transparent planar lens having a thickness of 6.0 mm (for surface hardness measurement) or 2.0 mm and an outer diameter of 75 mm was obtained in the same manner as in Example 1 except that the above was changed.

Casting polymerization of lens type 5 The monomer mixed solution composition of the photochromic polymerizable composition was 50% by mass of 2,2′-bis [4- (methacryloyloxyethoxy) phenyl] propane used in Example 1, triethylene glycol diester. A thickness of 6.0 mm (surface) was obtained in the same manner as in Example 1 except that 43% by weight of methacrylate, 6% by weight of α-methylstyrene, and 1% by weight of 2,4-diphenyl-4-methyl-1-pentene were used. (For hardness measurement) or 2.0 mm and a highly transparent flat lens having an outer diameter of 75 mm.

3. 1. Annealing of lens after mold release Each type of 2.0mm lens obtained in 1 above is divided into 48 lots, and after cleaning the lenses in each lot, they are left in a furnace at the furnace temperature shown in Table 2 for 2 hours (annealing). did. Regarding the surface hardness measurement lens, it was confirmed that there was no surface hardness change before and after annealing.

4). Evaluation of presence or absence of surface defects 3. After annealing, irradiation with a high-pressure mercury lamp was performed, and the transmitted light was imaged on a white screen about 1 meter ahead to observe the presence or absence of surface defects. Specifically, a white screen was placed on a table with an illuminance of 200 lux at a distance of 1 meter from the same lamp as the high-pressure mercury lamp, and the illuminance of the screen was adjusted to 1000 lux. The lens to be inspected was slowly moved between the lamp and the screen, and the light transmitted through the lens was imaged on the screen to observe the presence or absence of surface defects. When the uneven unevenness of local illuminance due to minute unevenness (orange peel) on the lens surface was found visually, it was evaluated as orange peel, and when it was not found, it was evaluated as no orange peel. The results are shown in Table 2.

5. Confirmation of correlation between lens surface hardness and maximum temperature during heating The surface hardness of the lens formed by cast polymerization by heat treatment is determined by the composition of the raw material liquid and the heat treatment conditions for polymerization. The lens for which the defect evaluation was performed has the same surface hardness as the surface hardness measurement lens molded under the same heat treatment condition using the same raw material liquid. The surface hardness HR was as shown in Table 1.
A graph in which the lens surface hardness HR is plotted against the item D in Table 2 is shown in FIG. When the graph shown in FIG. 1 was linearly approximated by the method of least squares, the linear function shown in FIG. 1 was obtained.
FIG. 2 is a graph in which the lens surface hardness is plotted against the logarithm of item D in Table 2. When linear approximation is performed by the least square method, the linear function shown in FIG. 2 is obtained.
The linear functions shown in FIG. 1 and FIG. 2 both have a correlation coefficient square R ² exceeding 0.99, and therefore, between the maximum temperature at which the orange peel occurrence rate is 0% and the lens surface hardness. It was confirmed that a good correlation was established, that is, a non-orange peel-free product could be obtained by performing heat treatment at a lower temperature for a lens with a softer surface. For example, in actual manufacturing, the heat treatment applied to the lens after mold release is set to a temperature equal to or lower than the maximum temperature calculated using the linear function obtained here, so that high-quality glasses plastic without orange peel A lens can be obtained.
Also, from the above results, when mass-producing a plurality of plastic lenses with different surface hardness, heat treatment applied to the lens after mold release is performed at a lower temperature for a lens with a softer surface so that high quality without orange peel can be obtained. It can also be confirmed that a plastic lens for spectacles can be obtained. In addition, from the results shown in Table 2, as specified in Method 3, the maximum temperature during heat treatment is 110 ° C. or less for lenses of HR 95 or more and 100 or less, and 105 ° C. or less for lenses of more than 90 and less than 95, For lenses less than 90 and less than 90 but less than 100 ° C, and for lenses less than 85, set to 95 ° C or less, a high-quality plastic lens for eyeglasses without orange peel has an extremely high orange peel rate of 0%. It can also be confirmed that it can be provided at a high yield.
In addition, although the heat processing performed above is annealing, when forming a cured film (for example, hard coat) using a thermosetting composition after annealing is performed on the lens after release as necessary. The heating temperature for the thermosetting treatment is also set to the lens surface hardness in the same manner as described above, thereby preventing the occurrence of orange peel due to the thermosetting treatment.

6). Evaluation of Photochromic Performance Photochromic performance was evaluated by the method described above for each type of lens that was confirmed to have no orange peel after annealing. The results are shown in Table 3 together with the Rockwell hardness shown above.

From the results shown in Table 3, it can be confirmed that the color density and the light response speed of the plastic lens containing the photochromic compound can be improved by reducing the surface hardness.
Plastic lenses with improved photochromic performance by softening the surface in this way tend to have significant orange peel as described above. By carrying out below the maximum temperature set based on the above, it is possible to prevent the occurrence of orange peel due to the heat treatment.

  The present invention is useful in the field of manufacturing eyeglass lenses.

Claims (4)

Injecting a plastic lens raw material liquid containing a curable component into the cavity of a mold having two molds facing each other at a predetermined interval and a cavity formed by closing the interval;
A plastic lens raw material solution is cured in the cavity to obtain a plastic lens,
Releasing the resulting plastic lens from the mold, and
Heat-treating the released plastic lens,
A method of manufacturing a plastic lens for spectacles to obtain a plurality of plastic lenses for spectacles by performing a manufacturing process including a plurality of times,
The plastic lens after the release includes a lens having a surface hardness of R scale Rockwell hardness of 100 or less, and the maximum temperature in the heat treatment is set to a lower temperature for a plastic lens having a lower surface hardness after the release. A method for producing a plastic lens for spectacles. Injecting a plastic lens raw material liquid containing a curable component into the cavity of a mold having two molds facing each other at a predetermined interval and a cavity formed by closing the interval;
A plastic lens raw material solution is cured in the cavity to obtain a plastic lens,
Releasing the resulting plastic lens from the mold, and
Heat-treating the released plastic lens,
A method for producing a plastic lens for spectacles, comprising:
The surface hardness of the plastic lens after release is R scale Rockwell hardness of 100 or less, and the maximum temperature in the heat treatment is set based on a predetermined correlation, where the correlation is the surface after release. A method for producing a plastic lens for spectacles, characterized in that a plastic lens having a lower hardness has a lower maximum temperature. Injecting a plastic lens raw material liquid containing a curable component into the cavity of a mold having two molds facing each other at a predetermined interval and a cavity formed by closing the interval;
A plastic lens raw material solution is cured in the cavity to obtain a plastic lens,
Releasing the resulting plastic lens from the mold, and
Heat-treating the released plastic lens,
A method for producing a plastic lens for spectacles, comprising:
The surface hardness of the plastic lens after the release is R scale Rockwell hardness of 100 or less, and the maximum temperature in the heat treatment is 110 ° C. or less and more than 90 for lenses having an R scale Rockwell hardness of 95 or more and 100 or less. A method for producing a plastic lens for spectacles, wherein the temperature is set to 105 ° C. or lower for lenses less than 95, 100 ° C. or lower for lenses greater than 85 and 90 to 90, and 95 ° C. or lower for lenses below 85. The manufacturing method of the plastic lens for spectacles of any one of Claims 1-3 which obtains the plastic lens which shows photochromic property by using the plastic lens raw material liquid containing a photochromic compound as the said plastic lens raw material liquid.