JP2007206711A - Plastic lens for eyeglasses with high refractive index - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lightweight plastic lens for eyeglasses with a high refractive index, the lens having high shock resistance and generating extremely little interference fringes. <P>SOLUTION: The plastic lens for eyeglasses with a high refractive index is obtained by preparing a plastic lens made of a polyurethane resin obtained by polymerizing at least one kind of polyisocyanate compound and at least one kind of polythiol and/or sulfur-containing polyol, forming a primer layer made of a polyurethane resin having at least 0.8 μm thickness on the surface of the plastic lens and further applying an organosiloxane hard coat layer having a refractive index of 1.47 or more thereon, and further applying at least one layer of a metal thin film on the hard coat layer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a plastic lens for high refractive index glasses having excellent impact resistance.

  Plastic lenses for eyeglasses have characteristics that are not found in glass lenses such as light, hard to break, and easy to dye. After passing through acrylic resin, polycarbonate resin, and ADC resin, high refractive index urethane resin is currently used for refraction. Those with a rate exceeding 1.60 are on the market.

  However, although the plastic lens improves the optical properties of the resin, the scratch resistance is much lower than that of the glass lens. Accordingly, it is an indispensable condition to deposit a hard coat layer on the lens surface. On the other hand, when the refractive index is 1.60 or more, in the minus lens, the thickness of the peripheral portion of the lens can be reduced, and a good-looking lens is obtained. Further, in order to reduce the weight of the lens, it is required to reduce the thickness of the central portion as much as possible, to improve the aberration due to the aspherical surface, and to further reduce the thickness of the peripheral portion.

Furthermore, in order to improve the scratch resistance, a hard coat layer using organic silicon, epoxy resin, or the like is provided. For this reason, a metal thin film for forming an antireflection layer located on the hard coat layer is extremely close. Although effective, when the antireflection layer is cracked by impact, the crack grows up to the lens body, and finally has a great disadvantage that the lens is destroyed at a stretch. Generally, when a hard coating layer is directly formed on a plastic lens, and an inorganic material such as TiO ₂ , ZrO ₂ , SiO ₂ is vacuum deposited on the upper layer, these layers are hard but very brittle, so the impact resistance is low, It is said that the impact resistance is reduced to 1/20 compared to the lens body when these coatings are simply carried out because cracks are easily generated. Patent Document 1 and Patent Document 2 describe that a polyurethane obtained from a specific polyol or active hydrogen-containing compound and diisocyanate or polyisocyanate is used as a primer on a lens made of diethylene glycol bisallyl carbonate or a copolymer thereof. The center thickness of the lens used is 1.6 mm or 1.2 mm. Today's high-refractive-index lenses make use of the high-refractive index to make even thinner lenses. The center thickness of the lens can be 0.7 mm or more and less than 1.2 mm. In the case of a lens, the edge thickness is thin. In the lens, a lens having a thin center thickness and high fashionability can be provided. However, impact resistance tends to decrease extremely as the lens becomes thinner.

  Further, the impact resistance test is usually performed according to the FDA standard, and a steel ball having a weight of about 16.4 g and a diameter of about 16 mm is dropped from 127 cm and evaluated, but the American National Standard (ANSI Z87.1). In 1989), for example, an evaluation method for dropping a steel ball having a diameter of 25.4 mm from 127 cm is specified as industrial safety glasses, which further enhances the safety of the wearer. The present inventors have aimed to develop a highly safe spectacle lens having impact resistance that satisfies the regulations for industrial use in order to ensure further safety of spectacle wearers. As a method of evaluating the impact resistance of a lens, the above-mentioned FDA standard steel ball (16.4 g) or a steel ball having a weight several times that of the FDA standard is dropped, and the expression “several times the FDA” is used for safety. In some cases, however, the diameter of the steel ball increases, and the contact area during a drop impact increases, which is not a true magnification display. For the evaluation of safety, the present inventors use FDA-standard steel balls (16.4 g), and give impact energy to breakage by a test method based on the US OLA-approved BRUCETON method that gives speed to this. The required safety was evaluated. In the FDA standard, the impact energy is specified to be 0.204 joules, so it is displayed as a multiple of this.

  As described above, formation of a hard coat layer is indispensable for a plastic lens. However, when the refractive index of the lens body exceeds 1.60, reflected light from the interface between the hard coat layer and the lens and the hard coat layer are formed. Reflected light from the surface interferes with each other, generating interference fringes. Theoretically, it is sufficient that the refractive indexes of the lens body and the hard coat layer are equal, but at present there is a difference of 0.1 or more. On the other hand, it may be possible to prevent interference fringes by making the thickness of the hard coat layer very thin. However, even if the wavelength of visible light is in the range of 400 nm to 700 nm and only one wavelength can be accommodated, other wavelengths In other words, such a thin film cannot exhibit the effect of scratch resistance.

With the commercialization of plastic lenses for high-refractive-index glasses, the present inventors have shown the results in Patent Document 3. However, in order to improve productivity and quality, the inventors have repeated trials and reached the present invention. Is.
JP-A 63-87223 JP 63-14001 A JP-A-5-341239

  The problem to be solved is to obtain a spectacle lens having a wide range of permissible values for the surface treatment performed on the lens body, a stable quality and a high impact resistance, and extremely few interference fringes.

  In the present invention, (1) on the surface of a plastic lens using a polyurethane resin obtained by polymerizing at least one polyisocyanate compound and at least one polythiol and / or sulfur-containing polyol, A high refractive index glasses in which a primer layer made of polyurethane resin is formed, an organosiloxane hard coat layer having a refractive index of 1.47 or more is further formed thereon, and at least one metal thin film is provided on the hard coat layer. Lies in plastic lenses.

  The present invention resides in (2) the plastic lens for high refractive index glasses according to the above (1), wherein the primer layer is formed by touch drying.

  The present invention resides in (3) the plastic lens for high refractive index glasses according to the above (1), wherein the refractive index of the plastic lens is 1.59 or more.

  According to the present invention, (4) when the thickness of the central portion is 0.7 mm or more and less than 1.2 mm, the impact energy value is 4 times or more than the FDA standard value 0.204 Joule, and the mechanical strength is as described in (1) above. It exists in plastic lenses for high refractive index glasses.

  This invention exists in the plastic lens for high refractive index glasses as described in said (1) which mix | blended the ultraviolet absorber with the (5) hard-coat layer.

  The present invention includes (6) at least one of the interface between the plastic lens and the primer layer, the interface between the primer layer and the hard coat layer, the interface between the hard coat layer and the metal thin film, and the interface between the hard coat layer and air. The plastic lens for high-refractive-index glasses according to the above (1), which has a fine uneven surface with a curvature radius of 15 nm to 150 nm.

  In addition, as long as the objective of this invention is met, the structure which combined said (1)-(6) suitably is also employable.

  According to the lens for high refractive glasses of the present invention, although it has a thin center thickness of 0.7 mm or more and less than 1.2 mm, it has an impact resistance that is four times or more of the FDA standard and most of interference fringes. A lightweight lens can be provided.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as necessary. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Further, the positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios.

  In the plastic lens for high refractive index glasses according to this embodiment, the resin constituting the lens body to be used is a refractive index obtained by polymerizing at least one polyisocyanate compound and at least one polythiol and / or sulfur-containing polyol. It is a polyurethane resin of 1.59 or more.

  The polyisocyanate is selected from aliphatic, aromatic or alicyclic diisocyanates, and m-xylylene diisocyanate, isophorone diisocyanate, tolylene diisocyanate, hexamethylene diisocyanate, 4,4′-diphenylmethane diisocyanate and the like are preferably used.

  Polythiols include di (2-mercaptoethyl) ether, pentaerythritol tetrakisthioglycolate, pentaerythritol tetrakis (3-mercaptopropionate), 1.2-bis [(2-mercaptoethyl) thio] -3-mercapto Dithiol such as propane or polythiol is preferably used.

  Further, in the plastic lens for high refractive index glasses according to this embodiment, a primer layer made of polyurethane resin having a thickness of at least 0.8 μm is formed on the surface of the lens body.

  Examples of polyurethane resins include thermoplastic polyurethanes synthesized from diisocyanates and diols disclosed in JP-A-63-87223 and JP-A-61-287680, or thermosetting disclosed in JP-A-3-109502. Polyurethane is used. Further, as disclosed in JP-A-6-337376, a polyurethane resin containing inorganic fine particles can also be used.

  In the plastic lens for high refractive index glasses according to this embodiment, an organosiloxane hard coat layer having a refractive index of 1.47 or more is formed on the surface of the primer layer, and further on the hard coat layer. At least one metal thin film is provided to provide an antireflection function, and even when the thickness of the lens center portion is 0.7 mm or more and less than 1.2 mm, the impact energy value is four times or more of the FDA standard value 0.204 Joule. It has strength.

  The resin forming the hard coat layer is made of a curable composition mainly composed of a silicon resin, and has a carbon group having an alkyl group, alkenyl group, allyl group, vinyl group or epoxy group, halogen group, amino group, methacryloxy group, etc. Examples include a composition in which colloidal silica having a particle diameter of 1 to 50 mμ is dispersed in a base resin typified by a silanol compound substituted with a hydrogen group or the like, a hydrolyzate or a partial condensate thereof. Further, fine zirconia, iron or the like may be added for the purpose of increasing the refractive index.

  Further, by adding an ultraviolet absorber to the resin constituting the hard coat layer, the lens body, the primer, and the resins constituting the hard coat are prevented from deteriorating, and the eyeball is protected.

  Further, at least one of a plastic lens / primer layer interface, a primer layer / hard coat layer interface, a hard coat layer / metal thin film interface, and a hard coat layer / air interface has a radius of curvature of 15 nm to 150 nm. The fine uneven surface is formed to form an inhomogeneous layer, and interference fringes due to reflected light are removed.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example.

Example 1
In FIG. 1, reference numeral 1 denotes a cross section of the plastic lens for high refractive index glasses of the present invention. As polyurethane resin using polyisocyanate compound (liquid A) and polythiol (liquid B), MR-7 (trade name) manufactured by Mitsui Toatsu Chemicals Co., Ltd. was prepared in an equivalent ratio of 1: 1. Then, after adding a catalyst and stirring sufficiently, deaeration is performed. The prepared resin is poured into a predetermined negative lens casting cell and once stored in a cool and dark room, natural deaeration is performed all day and night. Immediately after taking out from the cool dark room, the inlet is sealed, put into a heater, and gradually heated from room temperature to 100 ° C. for about 20 hours. The cell part was disassembled and the cured resin part was taken out. In order to remove the remaining unreacted part, the resin part was completely cured by annealing again at 120 ° C. for 2 hours to obtain a plastic lens 2. The gap of the casting cell was adjusted so that the center thickness of the lens was 0.7 mm and 1.0 mm, respectively.

  The two plastic lenses thus obtained were washed with pure water and an ultrasonic cleaner, dipped in a primer solution made of polyurethane resin, and applied to obtain a film thickness of 0.8 μm and 2 μm, respectively. 3-1. If it is 0.8 μm or less, impact energy cannot be absorbed and cracks are caused. On the other hand, when the thickness is larger than 3 μm, the surface accuracy is poor and the transmitted image is distorted.

  When the primer layers 3 and 3-1 are dry to the touch, they are dipped into an organosiloxane hard coat solution and controlled so that the film thickness when dried is 2.6 μm. However, it goes without saying that the film thickness is constant on one lens, and if it is not uniform, irregular interference fringes are generated, which makes the appearance worse. If this hard coat layer is 2 μm or less, the scratch resistance and impact resistance will be insufficient, and conversely if it exceeds 4 μm, the surface accuracy will be lowered and the surface accuracy will be lowered. On this hard coat layer, an antireflection metal film comprising 5 layers was applied by vapor deposition. The impact energy by the BRUCETON method was 0.86 Joule when the lens center thickness was 0.7 mm, and 1.56 Joule when the thickness was 1.0 mm, which was 4.2 times and 7.5 times that of FDA, respectively. .

  By adding about 2% by weight of UV absorber of benzophenone derivative to the above hard coat solution, UV light below 380 nm is completely cut, so that the fastness to sunlight increases and the lens body and hard coat layer deteriorate. In addition to preventing, it can also protect the eyeball. A benzotriazole derivative, a cyanoacrylate derivative, etc. can also be used for the ultraviolet absorber used for the present Example.

(Comparative Example 1)
A lens provided with a hard coat layer and an antireflection layer was prepared in the same manner as in Example 1 except that the center thickness of the lens was 0.5 mm and the primer layer thickness was 0.1 μm. The impact energy according to the BRUCETON method was 0.20 joules, which was 1 time that of FDA, which was insufficient for safety.

(Comparative Example 2)
In the same manner as in Example 1, a primer having a thickness of 0.8 μm was applied to a lens having a center thickness of 1.1 mm made of diethylene glycol diallyl carbonate (CR-39) to form a hard coat having a thickness of 2.5 μm. An antireflection layer was formed thereon to obtain a lens. The impact energy by the BRUCETON method was 0.16 joules, and cracks were generated.

(Example 2)
The case where the heterogeneous layer is formed at each interface of the lens body 2, the primer layer 3, the hard coat layer 4 and the air will be described as an example. The purpose is to form inhomogeneity by immobilizing SiO ₂ ultrafine particles in close contact with a single layer and transferring the surface shape of the ultrafine particles to the mold on the lens objective surface side of the casting cell. It is.

The coating solution was prepared by first dissolving ethyl silicate [Si (OC ₂ H ₅ ) ₄ ] in ethanol, and then making a solution containing H ₂ O for hydrolysis and HNO ₃ as a catalyst. 10% by weight of ultrafine particles of SiO ₂ having a particle size of 120 nm are added. Adjust PH and disperse sufficiently. The mold is dipped into the adjusted solution and pulled up at a speed of 5 mm / s vertically. After evaporation of the volatile components, the coating solution was dried at 200 ° C. for 30 minutes. In this way, the ultrafine particles of SiO ₂ are fixed in close contact with the single layer on the molding surface of the mold.

  A high-refractive-index eyeglass lens is produced in the same manner as in Example 1 using the mold described above. Since the resin constituting the lens body undergoes volume shrinkage in the heat polymerization process, the mold is pressed so that early mold release does not occur by following the mold. When the predetermined polymerization is completed, the polymer is taken out from the heating furnace, slowly cooled to room temperature, the cell is disassembled, and the lens 6 is taken out. A curved surface corresponding to the radius of the particle diameter is closely transferred to the objective surface side of the lens, and this molding surface becomes the heterogeneous layer 7 (FIG. 2). Further, this lens is subjected to ultrasonic cleaning with pure water and dried, and then a predetermined primer layer is applied to form primer layers 8 and 8-1, and then a hard coat layer and a metal thin film layer are sequentially formed to complete the finished lens 9. obtain. In the lens thus obtained, the reflected light on the surface of the lens 6 is kept within 0.3%, and the light that interferes with the reflected light on the surface of the hard coat layer is so small that the interference fringes cannot be visually recognized. The center thickness of the lens was 1.1 mm, the impact energy was 1.56 joules, 7.5 times the FDA standard.

  When a metal stamper is produced from a mold in which the ultrafine particle surfaces used in this example are closely fixed with a single layer, a large number of molds having the same shape can be obtained. That is, nickel is vacuum-deposited on the mold surface to form a vapor deposition layer, and a metal mold is obtained by electroforming using the vapor deposition layer as an electrode. I can get the matrix. This second matrix is the same mold as the first mold.

  Further, in order to form a fine uneven surface on the outer surface of the hard coat layer, the second matrix may be used. In this case, the hard coat liquid is applied so that the hard coat layer has a thickness of about 2.5 μm, the hard coat layer 10 is formed, and the second matrix is pressed using a laminator that can be heated under reduced pressure. Thus, in the case of this example, a fine uneven surface with a curvature radius of 60 nm can be formed. This uneven surface becomes a heterogeneous layer 11 and exhibits an antireflection effect. Since the structure of the inhomogeneous layer is continuously changed from the refractive index on the air side to the refractive index of the substance (in this case, the refractive index of the hard coat layer 1.47), the reflectance is 1 at 400 nm as shown in FIG. Antireflection layer by multilayer metal thin film with reflectivity characteristics of 0.3% at 550nm, 0.4% at 700nm, and almost flat characteristics over the whole visible light range. Is not particularly necessary, but it is effective to apply a single layer in order to improve the scratch resistance. Further, a fluorine-based coating agent is applied to fine uneven surfaces to improve water repellency and stain resistance, and the refractive index of these films is as low as 1.36, which is useful for preventing reflected light.

  In addition, a method in which a hard coat liquid is applied to the second matrix surface in advance and pressed onto a primer layer formed on the lens to extrude an excessive hard coat liquid can also be used. In this case, the film thickness may be controlled by placing a spacer in an unnecessary portion around the lens. In any case, it is necessary to consider that air is not involved in the pressing process.

Industrial application fields

  The present invention relates to a plastic lens for high refractive index glasses having excellent impact resistance.

It is a schematic cross section of the plastic lens for high refractive index glasses of the present invention. It is a schematic cross section of the high refractive index eyeglass plastic lens of the second invention. It is a schematic cross section of the plastic lens which formed the fine uneven surface in the hard-coat layer. It is a graph which shows the light reflectivity characteristic of the heterogeneous layer which consists of a fine uneven surface.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Plastic lens for high refractive index glasses 2 Lens body 3, 3-1 Primer layer 4, 4-1 Hard coat layer 5 Metal thin film 6 Lens body 7 Inhomogeneous 8 Primer layer 9 High refractive index glasses plastic lens 10 Transfer surface 11 Homogeneous layer

Claims (6)

  A primer layer made of a polyurethane resin having a thickness of at least 0.8 μm is formed on the surface of a plastic lens using a polyurethane resin obtained by polymerizing at least one polyisocyanate compound and at least one polythiol and / or sulfur-containing polyol. A high refractive index spectacles plastic comprising an organosiloxane hard coat layer having a refractive index of 1.47 or more formed thereon, and further provided with at least one metal thin film on the hard coat layer. lens.   2. The plastic lens for high refractive index glasses according to claim 1, wherein the primer layer is formed by touch drying.   2. The plastic lens for high refractive index glasses according to claim 1, wherein a refractive index of the plastic lens is 1.59 or more.   2. The high refractive index according to claim 1, wherein when the thickness of the central portion is 0.7 mm or more and less than 1.2 mm, the impact energy value has a mechanical strength that is four times or more of the FDA standard value 0.204 Joule. Plastic lens for eyeglasses.   The plastic lens for high refractive index glasses according to claim 1, wherein an ultraviolet absorber is blended in the hard coat layer.   At least one of the interface between the plastic lens and the primer layer, the interface between the primer layer and the hard coat layer, the interface between the hard coat layer and the metal thin film, and the interface between the hard coat layer and air. 2. The plastic lens for high-refractive-index glasses according to claim 1, further comprising a fine uneven surface having a curvature radius of 15 nm to 150 nm.

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