JP2006243583A - Method for removing optical surface film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for removing an optical surface film, with which a surface film, of a plastics optical element with the surface film disposed on the optical surface thereof, is removed without damaging the optical surface of the plastics optical element. <P>SOLUTION: The surface film is removed by concurrently using chemical immersion treatment and mechanical polishing treatment. The immersion treatment is stopped in a state in which the surface film is still remaining on the optical surface before the optical surface of the plastics optical element is eroded with the chemical immersion treatment, and the remaining surface film which has been softened with the chemical treatment is removed by scraping it off with the polishing treatment. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a method for removing a surface film provided on an optical surface of a plastic optical element such as a plastic lens.

Plastic lenses are lighter than glass lenses and have better moldability, processability, and dyeability.
Since it is hard to break and has high safety, it is widely used in the field of spectacle lenses. However, since the plastic lens is soft and very easily damaged, a hard coat film having a high hardness is provided on the surface of the plastic lens to improve the scratch resistance. Furthermore, an antireflection film in which an inorganic substance is deposited may be provided on the surface of the hard coat film for the purpose of preventing surface reflection. This hard coat film is very useful for plastic lenses because it is a process that provides many functions such as improving adhesion to deposited films such as antireflection films and stabilizing dyeability in addition to imparting scratch resistance. is there. In addition, the plastic lens subjected to the surface treatment of the hard coat film or the antireflection film has a disadvantage that the impact resistance is lowered. In order to improve the impact resistance, the plastic lens base material, the hard coat film, A primer film may be provided between the two.

These surface films on the optical surface of the plastic lens substrate are provided after the plastic lens substrate is manufactured. Therefore, in the process of providing these surface films, for example, if a defect occurs in the hard coat film or a defective appearance such as dripping occurs, the plastic lens base material is expensive. It is necessary to reuse the lens substrate.

As a method for removing the surface film, as shown in Patent Document 1 below, a method of immersing the organopolysiloxane-based cured film in an alkaline aqueous solution has been proposed. Actually, the surface film can be removed simply by immersing the plastic lens substrate in an alkaline aqueous solution.
Japanese Patent Publication No. 2-36309

However, depending on the type of material of the plastic lens substrate, it is recognized that not only the surface film but also the plastic lens substrate is eroded when immersed in an alkaline aqueous solution, and the optical surface becomes rough. . In such a surface state, unlike a normal plastic product, the function as an optical surface is impaired, and the plastic lens base material cannot be reused.

The present invention has been made in view of the above circumstances, and provides an optical surface film removal method capable of removing the surface film of a plastic optical element having a surface film on the optical surface without damaging the optical surface of the plastic optical element. The purpose is to do.

In order to achieve the above object, according to the present invention, first, in the chemical solution for peeling off the surface film of a plastic optical element having an optical surface and having a surface film provided on the optical surface, the plastic optical An immersion step of immersing the element, an observation step of pulling up the plastic optical element from the chemical solution and observing the surface state of the plastic optical element by transmitted light or reflected light, and the surface film in the observation step is the plastic optical A polishing process for removing the surface film by polishing the surface of the plastic optical element through an abrasive when the state where the optical surface of the plastic optical element is peeled off from the element is observed. And the immersion step and the observation step are observed in a state where a part of the optical surface of the plastic optical element is exposed in the observation step. It provides a method for removing the optical surface film, which is repeated until the.

The method for removing an optical surface film of the present invention is to remove the surface film by using both chemical chemical immersion treatment and mechanical polishing treatment. Before the optical surface of the plastic optical element is eroded by the chemical immersion treatment, the chemical treatment is stopped with the surface film remaining, and the remaining surface film softened by the chemical treatment is easily scraped off by the polishing treatment. Can be removed. As a result, it has become possible to completely remove the surface film in a short time while preventing erosion of the optical surface of the plastic optical element in the case of only chemical solution immersion treatment. Furthermore, by observing the surface of the plastic optical element with reflected light or transmitted light, it is possible to confirm whether the surface state of the plastic optical element is a state in which a part of the optical surface is exposed.

The second aspect of the present invention is the optical surface according to the first optical surface film removing method, wherein the surface film has an organopolysiloxane-based cured film, and the chemical solution is an alkaline aqueous solution. A method for removing a film is provided.
Although an alkaline aqueous solution is effective as a chemical solution for peeling off the organopolysiloxane-based cured film, there is a high risk of eroding the surface of the plastic optical element, and the combined method of the present invention is effective.

Thirdly, the present invention provides a method for removing an optical surface film, wherein the plastic optical element is made of a urethane-based resin in the method for removing an optical surface film of the first or second aspect. .
Since the urethane resin is eroded with an alkaline aqueous solution and the optical surface is likely to be damaged, the combined method of the present invention is effective.

Fourthly, in the method for removing an optical surface film according to any one of the first to third aspects, the surface film is composed of any one or more of a primer film, a hard coat film, and an antireflection film. An optical surface film removing method is provided.
The method for removing an optical surface film of the present invention is effective as a method for removing these surface films provided on the optical surface of a plastic optical element.

Hereinafter, although the embodiment of the removal method of the optical surface film of the present invention is described, the present invention is not limited to the following embodiment.
The method for removing an optical surface film of the present invention is to remove the surface film provided on the optical surface of the plastic optical element and reuse the plastic optical element. It is removed together with a polishing treatment.

Examples of the plastic optical element that is an object of the optical surface film removal method of the present invention include optical lenses such as a light-transmitting plastic lens, a prism, and a cover disposed on the front surface of various light-transmitting plastic devices. An element can be illustrated. Examples of the light transmissive plastic material include resins used for optical articles such as polycarbonate, polystyrene, polyethylene terephthalate, methacrylic resin, (thio) urethane resin, thioepoxy resin, and allyl carbonate resin.

Among these, it is preferable to apply the method for removing an optical surface film of the present invention to a (thio) urethane-based resin that is easily eroded by an alkaline aqueous solution that is widely used for chemical solution immersion treatment. The thiourethane resin is obtained by polymerizing a polymerizable monomer mainly composed of a polyisocyanate having two or more isocyanate groups exemplified by m-xylylene diisocyanate and a compound having two or more active hydrogens. Obtained. Examples of the compound having two or more active hydrogens constituting the polymerizable monomer include 2 polyols having two or more hydroxyl groups and 4-mercaptomethyl-3,6-dithio-1,8-octanedithiol. A polythiol having one or more thiol groups or a compound having at least one hydroxyl group and one thiol group in one molecule is used. The mixing ratio of the polyisocyanate compound and the active hydrogen is such that the ratio of the isocyanate group (NCO) to the active hydrogen (H) is NCO / H (molar ratio) = 0.5 to 3.0, especially 0.8.
A range of 5 to 1.5 is preferably used.

Examples of the surface film provided on the optical surface of the plastic optical element include a hard coat film that imparts scratch resistance to the optical surface of the plastic optical element. In addition, an antireflection film that suppresses surface reflection may be provided on the hard coat film. Furthermore, a primer film that improves the impact resistance of a fragile plastic optical element may be provided between the plastic optical element and the hard coat film. In order of forming the surface film, a primer film is first provided, and then a hard coat film and further an antireflection film are provided. Therefore, the surface film to be removed is determined by the production process in which the surface film to be removed is generated. The primer film alone, the hard coat film alone, the primer film and the hard coat film, two layers, the primer film and the hard coat film And three layers of an antireflection film, and two layers of a hard coat film and an antireflection film.

As the hard coat film, an organopolysiloxane-based cured film in which inorganic oxide fine particles having an average particle diameter of 1 to 100 nm are mixed is generally used. This organopolysiloxane-based cured film is obtained by curing a curable composition mainly composed of an organosilicon compound represented by the following general formula (1): R ¹ _a R ² _b SiX _4-ab ... (1)
In the formula, R ¹ is an organic group having a polymerizable reactive group, R ² is a hydrocarbon group having 1 to 6 carbon atoms, X is a hydrolyzable functional group, a is 0 or 1, and b is 0 or 1.

Examples of the organic group having a polymerizable reactive group of R ^{1 in} the general formula (1) include a vinyl group, an allyl group, an acrylic group, a methacryl group, an epoxy group, a mercapto group, a cyano group, and an amino group. It is done. Specific examples of the hydrocarbon group having 1 to 6 carbon atoms of R ² include a methyl group, an ethyl group, a butyl group, a vinyl group, and a phenyl group. Specific examples of the hydrolyzable functional group for X include alkoxy groups such as methoxy group, ethoxy group, and methoxyethoxy group, halogen groups such as chloro group and bromo group, and acyloxy groups.

Specific examples of the organosilicon compound represented by the general formula (1) include vinyltrialkoxysilane, vinyltrichlorosilane, vinyltri (β-methoxy-ethoxy) silane, allyltrialkoxysilane, acryloxypropyltrialkoxysilane, methacryloxy Propyltrialkoxysilane, methacryloxypropyl dialkoxymethylsilane, γ-glycidoxypropyltrialkoxysilane, β- (3,4-epoxycyclohexyl) -ethyltrialkoxysilane, mercaptopropyltrialkoxysilane, γ
-Aminopropyltrialkoxysilane, N-β (aminoethyl) -γ-aminopropylmethyl dialkoxysilane, tetraalkoxysilane and the like. Two or more of these organosilicon compounds may be used in combination. Moreover, it is more effective to use this organosilicon compound after hydrolysis.

The curable composition for forming the hard coat film may contain a dye component such as a polyfunctional epoxy compound for imparting dyeability, a curing catalyst, and the like. The thickness of the hard coat film is generally in the range of 0.05 to 30 μm. When the hard coat film is applied by the dipping method, when the plastic optical element has a plurality of optical surfaces, the hard coat film is simultaneously formed on all the optical surfaces.

The antireflection film is composed of a single layer or multiple layers of an inorganic coating or an organic coating. There is also a multilayer structure of an inorganic coating and an organic coating. As the material of the inorganic coating, SiO ₂ , SiO, ZrO ₂ ,
_{TiO 2, TiO, Ti 2 O} 3, Ti 2 O 5, Al 2 O 3, Ta 2 O 5, CeO 2, Mg
Examples include inorganic substances such as O, Y ₂ O ₃ , SnO ₂ , MgF ₂ , and WO ₃ , and these are used alone or in combination of two or more. Among these, SiO ₂ capable of vacuum deposition at low temperature,
ZrO ₂ , TiO ₂ and Ta ₂ O ₅ are preferably used. Examples of the method for forming the inorganic coating include a vacuum deposition method, an ion plating method, a sputtering method, a CVD method, and a method of depositing by a chemical reaction in a saturated solution.

Examples of the material of the organic coating include FFP (tetrafluoroethylene-hexafluoropropylene copolymer), PTFE (polytetrafluoroethylene), ETFE (ethylene-tetrafluoroethylene copolymer), and the like. Plastic optical element And the refractive index of the hard coat film is selected. As a film forming method, the film is formed by a coating method having excellent mass productivity such as a spin coating method and a dip coating method in addition to a vacuum deposition method. In physical film forming methods such as vapor deposition, film formation is often performed sequentially for each optical surface of the antireflection film.

Moreover, as a primer film, the thing which has as a main component the polyester-type thermoplastic elastomer with a remarkable improvement in impact resistance can be mentioned. Examples of the polyester-based thermoplastic elastomer include those described in JP-A No. 2000-144048. The thickness of the primer film is in the range of 0.01 to 50 μm. The primer film may also contain inorganic oxide fine particles having an average particle diameter of 1 to 100 nm for adjusting the refractive index. The primer film is also formed on all optical surfaces simultaneously when being applied by the dipping method.

As a method of removing the surface film of a plastic optical element having such a surface film on the optical surface without affecting the optical surface of the plastic optical element, first, in the present invention, FIG.
As shown to (a), the plastic optical element 1 is immersed in the chemical | medical solution L which peels a surface film, and the immersion process which stops only to the extent which removes a surface film completely without removing with a chemical | medical solution is performed.

As a chemical | medical solution which peels a surface film | membrane, the alkaline aqueous solution which peels the organopolysiloxane type cured film which comprises a hard-coat film | membrane can be illustrated. In addition, it is of course possible to use a chemical solution that can peel off a surface film such as a hard coat film. The alkaline aqueous solution can not only peel the organopolysiloxane-based cured film but also the primer film. Further, only the antireflection film in the case of being composed of an inorganic vapor deposition film may be peeled off using, for example, hydrofluoric acid. However, the inorganic vapor deposition film is porous, and the alkaline aqueous solution can pass through the porous antireflection film to peel off the hard coat film, and by removing the hard coat film, the antireflection film can be removed. It is not necessary to remove only the antireflection film.

Examples of the alkaline aqueous solution include lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, and ammonia. Concentration of alkaline aqueous solution is 2-4
The weight is 0% by weight, the immersion time is several minutes to several hours, and the immersion temperature is in the range of room temperature to 90 ° C., but it is preferably determined while observing the state of the surface film in the observation step. The alkaline aqueous solution may contain an additive such as a surfactant.

An observation process is necessary to keep the surface film partially removed without removing it entirely with a chemical solution. In the observing step, the plastic optical element is pulled up from the chemical solution after a predetermined immersion time, light is applied to the lens surface, and the surface state of the plastic optical element is confirmed by visual observation of the reflected light. According to this method, the portion where the surface film remains on the lens surface always appears as interference fringes due to the reflected light. Therefore, it is possible to easily identify a portion where interference fringes are present and a portion where they are not present visually. It is also possible to identify the remaining state of the surface film by applying light to the lens surface and visually observing the transmitted light.

As described above, it is possible to confirm whether the surface state of the plastic optical element is a state where the surface film is peeled off and a part of the optical surface of the plastic substrate is exposed. And in an observation process, an immersion process and an observation process are performed repeatedly until the state where a part of said surface film remains is observed.

When the dipping process is completed, at least a part of the surface film remains. If the entire surface film is peeled off with a chemical solution, the optical surface of the plastic optical element may be eroded by the chemical solution. When a part of the surface film is peeled off and only a small part of the optical surface of the plastic optical element is exposed, or before it is exposed, the plastic optical element is pulled up from the chemical liquid, and the chemical liquid adhering to the surface of the plastic optical element is washed away. Stop peeling with chemicals.

The surface film remaining on the optical surface of the plastic optical element after the dipping process is peeled to some extent by the chemical solution and the hardness is lowered, but is not easily peeled mechanically, and is not polished in the next polishing process. The hardness is such that it can be removed by scraping with an agent. If the surface film is scraped off only by the polishing process without going through the dipping process, it takes a lot of time, and it is not realistic, and if it has a complicated curved surface such as a progressive refractive surface, uniform polishing Is difficult, and there is a possibility that the optical surface of the plastic optical element cannot be reproduced.

In the polishing process, the remaining optical film is scraped off by polishing the optical surface of the plastic optical element with an abrasive using the polishing apparatus shown in FIGS. 1 (b) and 1 (c). Are to be removed. In FIG. 1, a meniscus plastic spectacle lens is illustrated as an example of a plastic optical element. A spectacle lens has a convex surface and a concave surface, each of which is an optical surface. FIG. 1B shows a state in which the convex surface is polished by the polishing apparatus 101 for convex surface polishing, and FIG. 1C shows a state in which the concave surface is polished by the polishing apparatus 102 for concave surface polishing.

Referring to FIGS. 1B and 1C, polishing apparatuses 101 and 1 used in the polishing process step.
02 will be described. Polishing apparatus 101 for convex surface polishing and polishing apparatus 102 for concave surface polishing
The basic structure is the same except that the shape of the elastic abrasive is different. Polishing apparatus 101, 10
2 includes a lens holding unit 200 and an elastic polishing unit 300. The lens holding unit 200 includes a coaxial suction chuck 202 communicating with the hollow portion of the holding tube 201 at the upper end of a cylindrical holding tube 201. The suction chuck 202 is connected to a vacuum device (not shown) via a holding tube 201 and sucks and holds the lower surface side of the lens 1. The holding tube 201 can be moved up and down.

As shown in FIG. 1B, the elastic polishing body 301 for polishing the convex surface of the lens 1 has a substantially cylindrical shape, and is flat or slightly depressed so that the lower surface is substantially in close contact with the entire convex surface of the lens 1. It has a shape. As shown in FIG. 1C, the elastic polishing body 302 that polishes the concave surface of the lens 1 is circular and is formed in a dome shape so that the lower surface is in close contact with almost the entire concave surface of the lens 1. The upper surfaces of the elastic polishing bodies 301 and 302 are disk-shaped fixing plates 310 having substantially the same diameter.
A hollow rotating shaft 311 is vertically attached to the center of the fixed plate 310, and the elastic polishing bodies 301 and 302 are rotatably held around the rotating shaft 311 and are driven to rotate by a motor (not shown). It has come to be. At the center of the fixed plate 310, there is a rotating shaft 3
11 is formed with a water passage 313 for communicating the hollow 11 and the elastic polishing bodies 301 and 302 with each other.

As the elastic polishing bodies 301 and 302, a liquid-permeable polishing sponge can be used. The material is PVA, urethane, PP or the like. In addition, a sponge such as PVA, urethane, or PP in which an abrasive is dispersed can be used when forming the sponge.

The hollow rotating shaft 311 is provided with a supply unit (not shown) that can supply the slurry L1 containing the abrasive. The water inlet 3 is connected to the upper ends of the elastic polishing bodies 301 and 302 via the rotation shaft 311.
The slurry L <b> 1 supplied from 13 passes through the elastic polishing bodies 301 and 302 by gravity and flows out from the lower surface mainly in contact with the lens, and is supplied between the elastic polishing bodies 301 and 302 and the lens 1.

In such a polishing method using the polishing apparatuses 101 and 102, a slurry containing an abrasive is removed from the elastic polishing body 301, while the lower surface of the plastic lens 1 is adsorbed and held by the lens holding unit 200.
While supplying between 302 and the upper surface of the plastic lens 1, the elastic polishing bodies 301 and 302 are pressed while rotating to polish the upper surface of the plastic lens 1 with an abrasive. Since the elastic polishing bodies 301 and 302 have good shape followability to the lens 1 and a large contact area, uniform and rapid polishing is possible. Lens 1 with a polishing apparatus 101 for polishing a convex surface
The concave surface film is removed, and the concave surface film is removed by the polishing apparatus 102 for polishing the concave surface. The number of rotations of the elastic polishing bodies 301 and 302 is in the range of 30 to 500 rpm. The polishing time is about several seconds to several minutes, and usually about 30 seconds. As the abrasive, those generally marketed for polishing can be used. For example, Al ₂ O ₃ , CeO ₂ , SiO ₂ , Si
Examples thereof include metal oxides such as O, ZrO ₂ and Cr ₂ O ₃ , and carbides such as SiC and C. For the plastic lens 1, Al ₂ O ₃ (alumina) can be preferably used. The particle size and shape of the abrasive is the material of the plastic optical element to be polished,
It is arbitrarily determined depending on the shape and the type of the surface film. The reason why the abrasive is dispersed in water is to diffuse the frictional heat between the elastic polishing bodies 301 and 302 and the plastic lens 1 and to improve the shape following property to the optical surface.

In the above polishing process, the convex surface of the lens 1 is polished first, but the concave surface of the lens 1 may be polished first, and when the surface film is formed only on one surface, Only the surface may be polished.

In the above polishing apparatus, the lens holding portion is fixed, but the lens holding portion may be rotated in the opposite direction to the elastic polishing body to increase the relative speed between the lens and the elastic polishing body. In this case, it is preferable to shift the rotation center of the lens and the rotation center of the elastic polishing body so that there is no polishing residue.
Furthermore, the shape of the elastic polishing body is not limited to that shown in the figure, and for example, polishing may be performed on the side surface of a cylindrical elastic polishing body.

<Example 1>
(1) Production of thiourethane-based lens base material 94 g of m-xylylene diisocyanate as a raw material for plastic lenses and 87 g of 4-mercaptomethyl-3,6-dithio-1,8-octanedithiol as a polythiol
Is sufficiently stirred and mixed, and then ZelecUN (stepan) is used as an internal mold release agent.
Co., Ltd.) 0.15 g and 0.09 g of Viosorb 583 (manufactured by Kyodo Yakuhin) as an ultraviolet absorber were added and stirred to completely dissolve. Thereafter, 0.02 g of dibutyltin dichloride was added as a polymerization catalyst, and the mixture was sufficiently stirred and dissolved at room temperature, and then deaerated for 30 minutes while stirring under reduced pressure to 5 mmHg. This raw material was injected into two lens molding glass molds whose outer peripheral portions were sealed with tape, and the temperature was raised from 25 ° C. to 120 ° C. over 20 hours to be polymerized and cured. Thereafter, the cured plastic lens was released from the glass mold, and was annealed by heating at 120 ° C. for 2 hours. At this time, a glass mold having a lens power of −6D was used.
(2) Preparation and application curing of hard coat composition 100 parts of butyl cellosolve and 155 parts of γ-glycidoxypropyltrimethoxysilane were mixed and stirred sufficiently to make uniform. To this mixed solution, 43 parts of a 0.1N aqueous hydrochloric acid solution was added dropwise with stirring. The mixture was further stirred at room temperature for 4 hours, and then aged in a refrigerator overnight. Thereafter, 0.3 part of a silicone-based surfactant “L-7001” (manufactured by Nihon Unicar) was added and stirred, and then methanol-dispersed titanium dioxide / zirconium dioxide / silicon dioxide composite fine particle sol (manufactured by Catalyst Kasei Kogyo Co., Ltd., solid content concentration). 20 parts by weight) was mixed and thoroughly stirred. further,
After adding 0.7 parts of Fe (III) acetylacetonate, the mixture was stirred at room temperature for 3 hours and then aged overnight in a refrigerator for use as a hard coat composition. This hard coat composition was dipped on the plastic lens obtained in (1) above (with a lifting speed of 18).
cm / min), and the coated lens is air-dried at 80 ° C. for 20 minutes, and then 120 ° C.
Was baked for 120 minutes to form an organopolysiloxane hard coat film having a thickness of 2.0 to 2.2 μm on the lens fabric.
(3) Formation of antireflection film by dry method An antireflection film was provided on the plastic lens substrate on which the hard coat film obtained in (2) was formed by the following method. The plastic lens on which the hard coat film is formed is exposed to an argon gas plasma with an output of 200 W in a vacuum for 30 seconds, and then SiO ₂ , ZrO ₂ , SiO ₂ , ZrO ₂ , SiO ₂ , SiO ₂ , A five-layer thin film was formed. The optical thickness of the formed antireflection film is, in order from the lens side, the first SiO ₂ is about λ / 4, the total thickness of the next ZrO ₂ and SiO ₂ is about λ / 4, and the next ZrO ₂ is About λ / 4, the uppermost SiO ₂ is about λ / 4. The design wavelength λ at this time was 520 nm. Further, a water repellent film made of a fluorine-containing silane compound was formed on the antireflection film by a vacuum deposition method.
(4) Regeneration of lens with cured film (4-1) Immersion in alkaline chemical solution Pacna 100 (produced by Yuken Industry Co., Ltd., composed of NaOH and surfactant) in 1000 g of water 7
After dissolving 0 g, the lens obtained in the above (3) was immersed for 1 H in an alkaline chemical solution having a liquid temperature of 50 ° C., and then washed with water. Most of the surface film remained on the lens after immersion in the chemical solution.
(4-2) Surface polishing with an abrasive 100 g of alumina-based abrasive WA (manufactured by Fujimi Incorporated) 400 g of water
1 while using a polishing apparatus 101 for convex surface polishing and a polishing apparatus 102 for concave surface polishing as shown in FIG. 1 while dripping the polishing liquid agitated and dispersed in the urethane sponge at a speed of 0.5 cc / second. The convex surface and the concave surface were polished in order. The rotation speed of the sponge at this time was 200 rpm. The polishing time was 30 seconds on each side. After polishing, the lens was washed with water and dried to obtain a lens from which the cured film was removed.
No surface film remained on the regenerated lens, and no evidence of erosion was found on the optical surface.

<Example 2>
(1) Production of thiourethane-based lens substrate The same plastic lens as in Example 1 was produced.
(2) Formation of primer film and hard coat film (2-1) Preparation of primer composition and application curing Commercially available polyester resin “A-160P” (manufactured by Takamatsu Oil, water-dispersed emulsion, solid content concentration 25%) 100 Titanium oxide composite fine particles “OPTRAIK 1130F-2 (A-8
”” (Manufactured by Catalyst Chemical Industry, Fe ₂ O ₃ / TiO ₂ = 0.02, SiO ₂ / TiO ₂ = 0.1)
1, particle size 10 nm, solid content concentration 30%, dispersion solvent methyl alcohol, surface treatment tetraethoxysilane) 84 parts, dilution solvent methyl alcohol 640 parts, leveling agent silicone surfactant “SILWET L-77” (Japan) 1 part (manufactured by Unicar) was mixed and stirred for 3 hours to obtain a primer composition. This primer composition was applied to the plastic lens by a dipping method (pickup speed 20 cm / min), and the applied lens was heat-cured at 100 ° C. for 15 minutes to form a film thickness of 0.8 to 0.00 on the lens. A 9 μm polyester primer film was formed.
(2-2) Preparation of hard coat composition and coating curing After mixing 144 parts of butyl cellosolve, 603 parts of methanol-dispersed titanium dioxide / zirconium dioxide / silicon dioxide composite fine particle sol (catalyst chemical industry solid content concentration 20% by weight) , 170 parts of γ-glycidoxypropyltrimethoxysilane were mixed and stirred thoroughly.
To this mixed solution, 60 parts of 0.05N aqueous hydrochloric acid solution was added dropwise with stirring, and the mixture was further stirred for 4 hours.
After aging for a whole day and night, 0.2 part of Fe (III) acetylacetonate and 0.3 part of a silicone surfactant “L-7001” (manufactured by Nihon Unicar) were added and stirred at room temperature for 4 hours.
It was aged for one day in a refrigerator and used as a composition for hard coat. The hard coat composition was applied on the plastic lens on which the primer film obtained in (2-1) or (2-2) was formed by a dipping method (pickup speed: 18 cm / min), and the coated lens was 80
After air drying at 20 ° C. for 20 minutes, baking was performed at 120 ° C. for 120 minutes, and a film thickness of 2.0 was formed on the primer.
An organopolysiloxane hard coat film having a thickness of 2.2 μm was formed.
(3) Formation of antireflection film by dry method An antireflection film was constructed on the plastic lens substrate on which the primer film and the hard coat film obtained in (2) were formed. The SiO ₂ film is formed by a vacuum evaporation method (degree of vacuum: 2.0 × 10 ^−
4 Pa). The TiO ₂ film is formed by ion-assisted deposition (vacuum degree: 4.0 × 10 ^−
3 Pa). The ion assist conditions for forming the TiO ₂ layer by ion assist deposition are as follows: an acceleration voltage of 520 V, an acceleration current of 270 mA, and a degree of vacuum of 4.0 × 10 ⁻ by introducing oxygen.
^It was made to hold | maintain at ³ Pa. Counting from the substrate side, the first layer is an SiO ₂ layer (refractive index of 1.45) having an optical thickness of 0.083λ, and the second layer is a TiO ₂ layer having an optical thickness of 0.070λ (
(Refractive index 2.36), the third layer is an SiO ₂ layer having an optical film thickness of 0.10λ, and the fourth layer is 0.18.
TiO ₂ layer having an optical thickness of λ, the fifth layer is an SiO ₂ layer having an optical thickness of 0.065λ, the sixth layer is a TiO ₂ layer having an optical thickness of 0.14λ, and the seventh layer is 0 S with an optical film thickness of 26λ
An antireflection film was constructed by sequentially laminating iO ₂ layers. The design wavelength λ was 520 nm. Further, a water repellent film made of a fluorine-containing silane compound was formed on the antireflection film by a vacuum deposition method.
(4) Regeneration of lens with cured film (4-1) Immersion in alkaline chemical solution Pacna 100 (produced by Yuken Industry Co., Ltd., composed of NaOH and surfactant) in 1000 g of water 7
After dissolving 0 g, the lens obtained in (3) above was immersed in an alkaline chemical solution having a liquid temperature of 50 ° C. for 2 H, and then the lens was washed with water. Most of the surface film remained on the lens after immersion in the chemical solution.
(4-2) Surface polishing with an abrasive 100 g of alumina-based abrasive WA (manufactured by Fujimi Incorporated) 400 g of water
1 while using a polishing apparatus 101 for convex surface polishing and a polishing apparatus 102 for polishing concave surface as shown in FIG. 1, while dripping the polishing liquid stirred and dispersed in urethane sponge at a speed of 0.5 cc / second. The convex surface and the concave surface were polished in order. The rotation speed of the sponge at this time was 200 rpm. The polishing time was 30 seconds on each side. After polishing, the lens was washed with water and dried to obtain a lens from which the cured film was removed.
No surface film remained on the regenerated lens, and no evidence of erosion was found on the optical surface.

<Comparative Example 1>
(1) Production of lens with cured film A plastic lens was produced in exactly the same manner as in Example 2, and a primer film, a hard coat film, and an antireflection film were formed.
(2) Removal of cured film (2-1) Immersion in alkaline chemical solution Pacna 100 in 1000 g of water (manufactured by Yuken Industry Co., Ltd., composed of NaOH and surfactant) 7
After dissolving 0 g, the lens obtained in (1) above was immersed in an alkaline chemical solution having a liquid temperature of 50 ° C. for 2 H, and then the lens was washed with water. Thereafter, washing and drying were performed, but a cured film remained.

<Comparative example 2>
(1) Production of lens with cured film A plastic lens was produced in exactly the same manner as in Example 2, and a primer film, a hard coat film, and an antireflection film were formed.
(2) Removal of cured film (2-1) Immersion in alkaline chemical solution Pacna 100 in 1000 g of water (manufactured by Yuken Industry Co., Ltd., composed of NaOH and surfactant) 7
After dissolving 0 g, the lens obtained in (1) above was immersed in an alkaline chemical solution having a liquid temperature of 50 ° C. for 5 H, and then the lens was washed with water. Thereafter, washing and drying were performed, but the cured film could be removed, but the surface of the lens base material was bumpy and could not be recycled.

The optical surface film removal method of the present invention is used for the purpose of reclaiming a plastic optical element by removing the surface film of the plastic optical element on which the surface film is formed, and is used for the production of plastic lenses to improve the yield. be able to.

It is process drawing which shows the process of the optical surface film removal method of this invention.

Explanation of symbols

1: plastic optical element (lens), L: chemical, 101, 102: polishing apparatus, 301
302: Elastic polishing body, 200: Lens holding part, 300: Elastic polishing part, L1: Slurry

Claims (4)

An immersion step of immersing the plastic optical element in a chemical solution for peeling off the surface film of the plastic optical element having an optical surface and having a surface film provided on the optical surface;
An observation step of pulling up the plastic optical element from the chemical solution and observing the surface state of the plastic optical element by transmitted light or reflected light;
When the surface film is peeled off from the plastic optical element and a part of the optical surface of the plastic optical element is exposed in the observation step, the surface of the plastic optical element is polished with an abrasive. And a polishing treatment step for removing the surface film,
The method of removing an optical surface film, wherein the immersion step and the observation step are repeated until a state in which a part of the optical surface of the plastic optical element is exposed is observed in the observation step. In the removal method of the optical surface film of Claim 1,
The surface film has an organopolysiloxane-based cured film,
The method for removing an optical surface film, wherein the chemical solution is an alkaline aqueous solution. In the removal method of the optical surface film of Claim 1 or 2,
The method for removing an optical surface film, wherein the plastic optical element is made of urethane resin. In the removal method of the optical surface film in any one of Claims 1-3,
The method for removing an optical surface film, wherein the surface film is composed of at least one of a primer film, a hard coat film, and an antireflection film.

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