JP2011138043A - Plastic lens and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the deformation of a substrate caused by heating in a lens manufacturing process after film forming, when a relatively thick film (film of 20 μm or more) is disposed on one side of a lens. <P>SOLUTION: At least photochromic film 2 and a hard coat layer 5 are formed on one surface 1A of the substrate 1 for a plastic lens, and at least a stress reducing layer 3 for reducing the stress generated by thermal deformation in the lens manufacturing process of the photochromic film 2 is formed on the other surface 1B of the substrate 1. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a plastic lens for eyeglasses, for example, a plastic lens in which a relatively thick film such as a photochromic film is provided on one side, and a method for manufacturing the plastic lens.

  In recent years, plastic photochromic lenses (also referred to as light control lenses) using organic photochromic dyes are commercially available for eyeglasses. This photochromic lens has the same anti-glare effect as a high-density color lens by coloring in a bright outdoors, and has a function of recovering high transmittance when moving indoors. A photochromic lens is required to respond quickly when predetermined light is incident and develop a color at a high density, and to discolor quickly when placed in an environment without the light.

  As this photochromic lens, a lens having a structure in which a film made of a material in which a photochromic dye is dissolved on a lens substrate, that is, a photochromic film is provided is widely used. About photochromic film, material structure and method for producing photochromic lens with excellent photoresponsiveness (reaction speed and color density), color tone at the time of color development, and excellent adhesion to lens substrate and hard coat layer Various studies have been made.

For example, Patent Document 1 listed below describes a method of forming an ultraviolet curable photochromic film as a technique for forming a photochromic film on the convex surface side of a lens. In Patent Document 1, the optimum film thickness of the photochromic film is described as 20 μm to 50 μm, and if the thickness is not more than about 20 μm, the density and durability at the time of color development are suitably maintained. It is stated that it does not hit.
Patent Document 2 below discloses a technique for forming a photochromic film having a thickness of 30 μm on the convex surface of a lens.

JP 2007-77327 A JP 2007-77398 A

  By the way, when the material is an acrylic matrix, the photochromic film is subjected to an ultraviolet curing treatment, and when the material is a urethane matrix, a thermosetting treatment is performed to complete the film. However, in order to enhance the durability of the photochromic film, a protective film and a hard coat layer are further formed thereon, so that another heating process is added even after the thermosetting process of the photochromic film itself.

  That is, in the process of forming the protective film and the hard coat layer, usually, heating, ultraviolet irradiation, and the like are performed, and the lens substrate and the photochromic film are also heated accordingly, so that heat treatment in the subsequent process is inevitable. For this reason, the photochromic film may be contracted and deformed to some extent by the thermal history, and the stress acting on the substrate may become strong. When the stress becomes strong, especially in the case of a high refractive index material substrate having a thin lens thickness or a lens having a relatively low rigidity such that the lens substrate itself has impact resistance, the deformation due to the stress may increase. Also, in the case of a so-called minus lens (concave lens) in which the lens thickness decreases from the outer periphery of the lens toward the center, the amount of deformation may be significant.

  In view of the above problems, in the case where a relatively thick film of about 20 μm or more such as a photochromic film or the like is provided on one side of a lens, the present invention reduces the deformation of the substrate caused by the thermal history in the lens manufacturing process after film formation. The purpose is to suppress.

  In order to solve the above-described problems, a plastic lens according to the present invention has at least a photochromic film and a hard coat layer formed on one surface of a plastic lens substrate, and the photochromic film is formed on the other surface of the substrate. In this lens manufacturing process, at least a stress relaxation layer is formed to relieve stress on the substrate caused by thermal deformation of the photochromic film.

  The method for producing a plastic lens according to the present invention includes a step of forming a photochromic film on one surface of a plastic lens substrate, and a photochromic film in a lens manufacturing step after the photochromic film is formed on the other surface of the substrate. A step of forming a stress relaxation layer that relieves stress on the substrate caused by thermal deformation of the substrate, and a processing step involving generation of heat or heat to form another layer on the photochromic film. And it is characterized by performing the process of forming a stress relaxation layer before the process process accompanied by the heating or heat generation for forming this other layer.

  As described above, in the plastic lens of the present invention, a photochromic film is provided on one side of the plastic lens and a stress relaxation layer is provided on the other side, and the substrate is formed by thermal deformation of the photochromic film during the lens manufacturing process. The stress is relaxed by providing this stress relaxation layer. In this way, by relaxing the stress acting on the substrate from the photochromic film in the manufacturing process of other material layers such as a hard coat layer after the photochromic film is formed, the deformation of the substrate and the thermal deformation of the photochromic film itself are suppressed. be able to. For this reason, it becomes possible to suppress or avoid the occurrence of cracks or the like due to the deformation of the substrate on the surface of the hard coat layer or other material layers.

  Further, in the method for producing a plastic lens of the present invention, the above-described step of forming the stress relaxation layer is performed by heating or heat generation for forming another layer such that the photochromic film causes thermal deformation. For example, when the primer layer or the hard coat layer formed on the photochromic film is formed by heat curing or photocuring, it is performed before the step. According to this manufacturing method, since the stress relaxation layer is formed in advance, it is possible to reliably suppress the thermal deformation of the photochromic film in the subsequent process and the stress acting on the substrate, the hard coat layer, and the like.

  In the present invention, it is preferable that the difference between the refractive power of the substrate and the refractive power after the heat treatment in a state where the photochromic film and the stress relaxation layer are formed is less than 0.025D (diopter). . Specifically, the thermal history during the lens manufacturing process after forming the photochromic film and the stress relaxation layer is set in advance, and the photochromic film material is set so that the refractive power of the substrate is in the above range with respect to this thermal history. In addition, it is preferable to select the material and thickness of the stress relaxation layer. By configuring the stress relaxation layer in this manner, the amount of deformation of the substrate can be reliably suppressed, and occurrence of power defects due to substrate deformation can be avoided.

  In the plastic lens of the present invention, the thickness of the stress relaxation layer is preferably 40% or more and 120% or less of the thickness of the photochromic film. When the thickness of the stress relaxation layer is within the above range with respect to the thickness of the photochromic film, the deformation of the substrate in the heating process after the formation of the photochromic film is suppressed. When the thickness of the stress relaxation layer is thinner than the above range, the deformation effect by the photochromic layer is small. Further, when the thickness of the stress relaxation layer is thicker than the above range, the stress of the stress relaxation layer itself may be excessive.

Furthermore, the polymer component of the photochromic layer and the polymer component of the stress relaxation layer are preferably the same type. Here, the same species are those in which the monomer skeleton constituting the polymer is similar, and it is not necessary to match in detail such as the side chain of the monomer and the number of elements (specifically, carbon) constituting the monomer. For example, when the photochromic layer polymer component uses an acrylic monomer modified with some functional group, the stress relaxation layer polymer component is an acrylic layer made of an acrylic monomer having no modified functional group. include.
By matching the main polymer components, the thermal action and expansion of the photochromic layer and the stress relaxation layer are substantially equal, and deformation of the photochromic lens over time is suppressed.

  According to the plastic lens and the manufacturing method thereof of the present invention, the deformation of the substrate can be suppressed by suppressing the thermal deformation of the photochromic film in the heating step after the photochromic film is formed.

It is a schematic sectional block diagram of the plastic lens which concerns on embodiment of this invention. It is a figure which shows the board | substrate deformation amount before and behind the heating process of the plastic lens by a comparative example. It is a figure which shows the board | substrate deformation amount before and behind the heating process of the plastic lens by a reference example. It is a flowchart which shows the process of the manufacturing method of the plastic lens which concerns on embodiment of this invention. It is a figure which shows the deformation amount for every manufacturing process in the Example and comparative example of this invention. It is a figure which shows the deformation amount with respect to the thickness of the photochromic film | membrane in the Example and comparative example of this invention.

  Hereinafter, although the plastic lens which concerns on embodiment of this invention and its manufacturing method are demonstrated, this invention is not limited to the following embodiment. In each of the following embodiments, an example applied to a photochromic lens for eyeglasses and a method for manufacturing the same will be described, but it is also applicable to manufacturing various optical lenses that provide a photochromic function for purposes other than for eyeglasses. Is possible. The description will be made in the following order.

1. 1. Embodiment of plastic lens (1) Lens configuration (2) Substrate (3) Photochromic film (4) Stress relaxation layer (5) Hard coat layer (6) Antireflection film Embodiment 3 of manufacturing method of plastic lens Examples and Comparative Examples

1. Embodiment of Plastic Lens (1) Lens Configuration First, the configuration of a plastic lens according to an embodiment of the present invention will be described. As shown in the schematic cross-sectional view of FIG. 1, the plastic lens according to the present embodiment is configured by, for example, a first surface 1A made of a convex surface and a second surface 1B made of a concave surface as front and back optical surfaces, respectively. Each layer such as the photochromic film 2 is formed on the substrate 1. In the example shown in FIG. 1, the photochromic film 2 is formed on the first surface 1A, and the stress relaxation layer 3 is formed on the second surface 1B. Between the photochromic film 2 and the stress relieving layer 3 and the substrate 1, although not shown, an underlayer for improving adhesion may be formed as necessary. On the photochromic film 2 on the first surface 1A, a primer layer 4 for improving adhesion is formed as necessary, and a hard coat layer 5 and an antireflection film 6 are formed thereon. Similarly, a primer layer 7 is formed on the stress relaxation layer 3 as necessary, and a hard coat layer 8 is further formed thereon. Although not shown, for example, a functional layer having other functions such as water repellency and antifouling property may be provided on the antireflection film 6 on the first surface 1A.

  The stress relieving layer 3 has a material structure that has a function of suppressing deformation of the substrate 1 to some extent upon heating when forming each layer thereon after the photochromic film 2 is formed. As described above, when the photochromic film 2 is relatively thick, such as about 20 μm or more, the photochromic film 2 is polymerized to some extent in the photochromic film 2 during heating such as thermosetting in the formation process of the hard coat layer after the photochromic film 2 is formed. The photochromic film 2 contracts due to a reason such as advancement. The temperature rise during thermosetting is generally about 70 ° C. to 120 ° C., but there is also a temperature rise of about 70 ° C. during light irradiation when using a photocurable resin such as ultraviolet rays. Therefore, in the case of forming the thermosetting and photocurable material layers, the photochromic film 2 contracts to some extent. When the hard coat layer 5 and the like are cured with the photochromic film 2 contracted in this way, the shape of each layer is maintained, and the substrate 1 is finally deformed. When such deformation occurs, for example, in the case of a meniscus lens having a high refractive index, a relatively thin thickness, and a small curvature (large curvature radius), the curvature of the substrate 1 is smaller than that before the heating step. (The radius of curvature is larger), the shape may be nearly flat, and the curvature may be reversed.

  As a comparative example, FIG. 2 shows a result of measuring an example of the deformation amount of the substrate before and after the heating process in a photochromic lens having a conventional configuration in which such a stress relaxation layer 3 is not provided. In this example, a polythiol-based material having a refractive index of 1.67 is used as a substrate, a photochromic film is formed with a convex optical surface formed on one surface, and the other surface is optically polished to form a concave surface. Thus, the power of spherical power -1.25 is obtained. Thereafter, the height of the convex surface at each position of the substrate was measured before and after the step of forming the hard coat layer on the photochromic film, and obtained as the amount of deformation of the substrate. In FIG. 2, the solid line a indicates the shape of the substrate before the hard coat layer (HC) is formed, and the solid line b indicates the shape of the substrate after the hard coat layer (HC) is formed. As is clear from FIG. 2, it can be seen that the photochromic film is contracted by the heat treatment during the formation of the hard coat layer, and the convex surface of the substrate is deformed into a concave shape.

  On the other hand, as a reference example, the deformation amount of the substrate when the hard coat layer was formed by omitting the photochromic film using the same substrate was similarly obtained. The result is shown in FIG. In FIG. 3, the solid line c indicates the substrate shape before the hard coat layer is formed, and the solid line d indicates the substrate shape after the hard coat layer is formed. As can be seen from FIG. 3, when the photochromic film is not provided, the substrate is hardly deformed even by the heating process when forming the hard coat layer. Comparison of the results shown in FIGS. 3 and 4 shows that when the photochromic film is provided, the deformation of the photochromic film becomes significant when the refractive index of the substrate material is relatively high and the spherical power is relatively small. As shown in FIG. 2, when the substrate is deformed and the convex side becomes concave, when the spectacle lens is attached to the frame, a situation may occur in which the front and back of the lens are mistaken.

  On the other hand, in the plastic lens of the present embodiment, the stress relaxation layer 3 is provided on the second surface 1B side of the substrate 1 as described above. For this reason, in this stress relaxation layer 3, the stress applied to the substrate 1 due to the shrinkage of the photochromic film 2 is relieved by contracting to the same extent as the photochromic film 2 during the heating step in forming the hard coat layer 5 and the like. In addition, the deformation of the substrate 1 can be suppressed. Accordingly, it is possible to manufacture a plastic lens while suppressing variations and fluctuations in optical characteristics such as power. Further, by suppressing the deformation of the substrate 1, it is possible to suppress the cracking and peeling of each layer such as the hard coat layer 5 formed on the photochromic film 2, and to manufacture a plastic lens having a photochromic function with high productivity. Become.

  In addition, when providing such a stress relaxation layer 3, it is also possible to omit the other layers and to suppress the increase in the number of layers. For example, the primer layer 7 on the stress relaxation layer 3 is formed in order to obtain adhesion and impact resistance with the hard coat layer 8 on the stress relaxation layer 3. As the stress relaxation layer 3, for example, an acrylic resin or a urethane resin When the desired impact resistance is obtained and sufficient adhesion between the stress relaxation layer 3 and the hard coat layer 8 is obtained, the primer layer 7 is omitted, that is, the second surface 1B side. It is possible to replace the primer layer 7 with the stress relaxation layer 3.

  Further, the thickness of the stress relaxation layer 3 is preferably set to a thickness on the same order as the thickness of the photochromic film 2, for example, about 10 μm or more. Thus, when making a film thickness comparatively thick, while being able to use general acrylic resin and urethane type resin, it also has the advantage that the selection conditions of materials, such as a hard-coat layer, can be eased. For example, when a relatively high refractive index material having a refractive index of about 1.65 or more is used as the substrate 1, interference fringes are generated if the hard coat layer 5 or the like formed thereon has a low refractive index. The appearance will be worse. In order to suppress the generation of the interference fringes, the material such as the hard coat layer 5 needs to have a high refractive index. On the other hand, when the photochromic film 2 is provided, the photochromic film 2 is formed to be much thicker than the wavelength of visible light, about 20 μm, as described above. Such a material is not required to have a refractive index as high as that of the substrate 1. However, when the hard coat layers 5 and 8 are coated by the dip method or the like, for example, the hard coat layer 8 of the same material is also formed on the second surface 1B side. In order to suppress interference fringes, it is also necessary to use a high refractive index material.

  On the other hand, in this embodiment, when the thickness of the stress relaxation layer 3 is about the same as that of the photochromic film 2 or about 10 μm or more, it is necessary to suppress the interference fringes even when the refractive index of the substrate 1 is high. Disappear. Therefore, even when the hard coat layers 5 and 8 are formed by the dipping method, a material having a relatively low refractive index can be used as the material. This eliminates the need for materials such as titanium oxide fine particles to be added to the coating liquid for the hard coat layer in order to obtain a high refractive index, thereby providing a degree of freedom in material selection and reducing costs. .

Next, the material and forming method of each part of the plastic lens 10 will be described.
(2) Substrate material Examples of the substrate material applicable to the plastic lens according to the present embodiment include a copolymer of methyl methacrylate and one or more other monomers, diethylene glycol bisallyl carbonate, and one or more other monomers. Copolymer, polyurethane / polyurea copolymer, polycarbonate, polystyrene, polyvinyl chloride, unsaturated polyester, polyethylene terephthalate, polyurethane, polythiourethane, sulfide resin utilizing ene-thiol reaction, sulfur-containing vinyl polymer Examples include coalescence. These materials may contain various additives as necessary. Among them, a substrate material having a relatively high refractive index and having a refractive index of about 1.65 or more has a small curvature for obtaining the same power, that is, becomes thin, and thus deformation of the substrate tends to be a problem. Therefore, it is particularly preferable to apply the present invention.

  In general, as a plastic lens for spectacles, the optical surface is formed only on one surface, for example, the convex surface side, and the finished lens that forms various coating films after the optical surfaces on the front and back sides are completed in advance. There is a so-called semi-finished lens in which the other surface, for example, the concave surface side, is coated after forming an optical surface after receiving an order, but the present invention is applicable to both. In both the finished lens and the semi-finished lens, an effect of suppressing deformation of the substrate can be obtained by forming the stress relaxation layer in a predetermined process sequence, as will be described in the embodiment of the manufacturing method described later. In addition, the formation method of an optical surface is not specifically limited, such as a mechanical process and a shaping | molding process, The case where any processing method is used can be utilized.

(3) Photochromic film The photochromic film is formed by applying and curing a coating liquid having a photochromic dye on one surface, for example, the convex surface side of the substrate.
A coating liquid can be comprised from a sclerosing | hardenable component, a photochromic pigment | dye, a polymerization initiator, and the additive added arbitrarily. The method for preparing the coating liquid is not particularly limited, and the order of addition of the respective components is not particularly limited, and all the components may be added at the same time. Other additives may be added and mixed.

The coating liquid preferably has a viscosity at 25 ° C. of 20 to 500 cp, more preferably 50 to 300 cp, and particularly preferably 60 to 200 cp. By setting it as this viscosity range, application | coating of a coating liquid becomes easy and the photochromic film | membrane of desired thickness can be obtained easily.
Hereinafter, each component of the coating liquid will be described in detail.

(3-1) Curing Component The curable component that can be used for forming the photochromic film is not particularly limited, and includes (meth) acryloyl group, (meth) acryloyloxy group, vinyl group, aryl group, styryl group, and the like. Known photopolymerizable monomers and oligomers having radically polymerizable groups, and prepolymers thereof can be used. Among these, a compound having a (meth) acryloyl group or a (meth) acryloyloxy group as a radically polymerizable group is preferable because it is easily available and has good curability. Note that “(meth) acryloyl” refers to both acryloyl and methacryloyl.
As specific curable components, components described in JP2008-33223A, JP2007-77327A, and the like can be used.

(3-2) Photochromic dye compound As the photochromic dye compound, known ones can be used, and examples thereof include photochromic dye compounds such as a fulgimide compound, a spirooxazine compound, and a chromene compound. The photochromic dye compound can be used without particular limitation.
Examples of the fulgimide compound, spirooxazine compound, and chromene compound are described in, for example, JP-A-2-28154, JP-A-62-2288830, WO94 / 22850, and WO96 / 14596. A compound can be used conveniently.
As compounds having excellent photochromic properties, for example, JP 2001-114775 A, JP 2001-031670 A, JP 2001-011067 A, JP 2001-011066 A, JP 2000-347346 A. JP, 2000-344762, JP 2000-344761, JP 2000-327676, JP 2000-327675, JP 2000-256347, JP 2000-229976, JP 2000-229975, JP 2000-229974, JP 2000-229993, JP 2000-229972, JP 2000-219687, JP 2000-219686, JP 2000 No. 219865, Japanese Unexamined Patent Publication Nos. 11-322739, 11-286484, 11-279171, 10-298176, 09-218301, 09-124645, 08 The compounds disclosed in JP-A-295690, JP-A No. 08-176139, JP-A No. 08-157467 and the like can also be suitably used.

  Among these photochromic dye compounds, the chromene-based photochromic dye compounds have higher photochromic property durability than other photochromic dye compounds, and the improvement in color density and fading speed of the photochromic properties is particularly superior to other photochromic dye compounds. Since it is large, it can be used particularly preferably. Furthermore, among these chromene-based photochromic dye compounds, compounds having a molecular weight of 540 or more are preferably used since the improvement in the color density and the fading speed of the photochromic properties according to the present invention are particularly large compared to other chromene-based photochromic dye compounds. Can do.

(3-3) Photopolymerization initiator The photopolymerization initiator is not particularly limited. For example, benzoin, benzoin methyl ether, benzoin butyl ether, benzophenol, acetophenone, 4,4′-dichlorobenzophenone, diethoxyacetophenone, 2 -Hydroxy-2-methyl-1-phenylpropan-1-one, benzylmethyl ketal, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2 Isopropylthiooxane, bis (2,6-dimethoxybenzoyl-2,4,4-trimethyl-pentylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 2,4, 6-Trimethylbenzoyldiphenyl-sulfur Sphine oxide, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1 and the like, such as 1-hydroxycyclohexyl phenyl ketone, 2-isopropylthiooxanthone, bis (2,6-dimethoxy) Benzoyl-2,4,4-trimethyl-pentylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenyl-phosphine oxide are preferred.
These photopolymerization initiators can be used by appropriately mixing a plurality of types, and the blending amount of the photopolymerization initiator with respect to the total amount of the curable composition is based on 100 parts by weight of the radical polymerizable monomer. In general, it is 0.001 to 5 parts by weight, preferably 0.1 to 1 part by weight.

  In the case of curing by a method other than photopolymerization, for example, as a thermal polymerization initiator, diacyl peroxide such as benzoyl peroxide, p-chlorobenzoyl peroxide, decanoyl peroxide, lauroyl peroxide, acetyl peroxide, etc. Peroxyesters such as t-butylperoxy-2-ethylhexanoate, t-butylperoxydicarbonate, cumylperoxyneodecanate, t-butylperoxybenzoate; diisopropylperoxydicarbonate, di-2 -Percarbonates such as ethylhexyl peroxydicarbonate, di-sec-butyloxycarbonate; 2,2'-azopisisoptyronitrile, 2,2'-azopis (4-dimethylvaleronitrile), 2,2'- Azobis (2-methylbutyroni Lil), 1,1'-azobis (cyclohexane-1-carbonitrile) azo compounds such like.

  The amount of these thermal polymerization initiators used varies depending on the polymerization conditions, the type of initiator, the type and composition of the polymerizable monomer, but is generally 0.01 to 10 parts per 100 parts by weight of the total polymerizable monomer. It is preferable to use in the range of parts by weight. The above thermal polymerization initiators may be used alone or in combination.

(3-4) Additives In order to improve the durability of the photochromic dye, the color development speed, the fading speed and the moldability, the coating liquid further contains a surfactant, an antioxidant, and a radical scavenger. , UV stabilizers, UV absorbers, mold release agents, anti-coloring agents, antistatic agents, fluorescent dyes, dyes, pigments, fragrances, plasticizers, and other additives may be added. As these additives, known compounds are used without any limitation.

  Further, as the surfactant, any of nonionic, anionic and cationic types can be used. In consideration of solubility in the coating liquid, it is preferable to use a nonionic surfactant.

  Antioxidants, radical scavengers, UV stabilizers, UV absorbers include hindered amine light stabilizers, hindered phenol antioxidants, phenol radical scavengers, sulfur antioxidants, benzotriazole compounds, benzophenone compounds Etc. can be used suitably. These antioxidants, radical scavengers, ultraviolet stabilizers, and ultraviolet absorbers may be used in combination of two or more. Furthermore, when using these non-polymerizable compounds, surfactants and antioxidants, radical scavengers, UV stabilizers, and UV absorbers may be used in combination.

  Among the stabilizers, a hindered amine light stabilizer may be mentioned as a preferable stabilizer from the viewpoint of preventing deterioration of the photochromic dye during curing or improving the durability of the obtained photochromic film. As the hindered amine light stabilizer, known compounds can be used without any limitation.

  The coating liquid preferably contains a surfactant, a leveling agent, etc. in order to improve uniformity during film formation, and in particular, a silicone-based / fluorine-based leveling agent having leveling properties may be added. preferable.

  Furthermore, an adhesion agent such as a coupling agent or a polymerization catalyst for the coupling agent may be added to the coating liquid in order to improve adhesion.

(3-5) Curing conditions As a method of applying the coating liquid to the surface of the substrate, for example, a spin coating method, a dip method, a spray method, or the like can be applied as a method that is usually performed. The spin coating method is preferable from the viewpoint of the viscosity and surface accuracy of the composition. Especially when the spin coating method is used, the film thickness can be controlled more accurately. When applied to a semi-finished lens, the coating is applied to only one side of the substrate, so the other side can be optically polished to form a coating solution. This has the advantage that no waste occurs.

  Further, it is preferable to form an undercoat layer for improving adhesion described later before applying the coating liquid to one surface of the substrate. Further, the substrate 1 and the photochromic film are formed by subjecting the surface to be coated to oxidation / reduction treatment such as acid, alkali and ozone, chemical treatment using various organic solvents, physical treatment such as plasma and ultraviolet rays, and detergent treatment using various detergents. Adhesiveness with the coating liquid for 2 can be improved.

The curing conditions for the coating liquid are not particularly limited, and a known polymerization method according to the type of radical polymerizable monomer to be used can be employed. The polymerization initiation means can be carried out by heat, irradiation with ultraviolet rays, α rays, β rays, γ rays or the like, or a combination of both. Preferably, ultraviolet rays are irradiated and cured, followed by further heat curing. preferable.
As a light source used for curing by ultraviolet rays, a known light source can be used without any limitation, and specific examples include an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a xenon lamp, a carbon arc, a germicidal lamp, an electrodeless lamp and the like. It is done.
The light irradiation time can be appropriately determined depending on the type of ultraviolet polymerization initiator, the absorption wavelength, the sensitivity, the desired film thickness of the photochromic film 2, and the like.

  The film thickness of the photochromic film 2 is preferably 10 μm to 100 μm, and more preferably 20 μm to 50 μm in consideration of the density at the time of color development, durability and heat resistance, and film uniformity. In particular, when the thickness is 20 μm or more, it is more preferable to apply the present invention because the deformation of the substrate in the heating step after photochromic formation becomes significant.

(3-6) Underlayer for Photochromic Film Although not shown in FIG. 1 between the photochromic film 2 and the substrate 1, it is preferable to provide an underlayer. For this underlayer, polyurethane resin, polyester resin, epoxy resin, melamine resin, or polyurethane acrylate resin can be used. Although the formation method of a base layer is not specifically limited, It can obtain by preparing the coating liquid which can form a base layer, apply | coating to 1 A of 1st surfaces, and performing a hardening process. A coating method is not particularly limited, but coating by a dip method or a spin method is preferable. Since the photochromic film is formed only on one surface, a spin method capable of forming a film only on one surface is particularly preferable.

  The thickness of the underlayer is not particularly limited as long as it can improve the bonding state between the first surface 1A and the photochromic film 2. A preferable film thickness is 1 μm to 20 μm, and more preferably 3 μm to 10 μm. When the film thickness is thinner than 0.5 μm, it is difficult to ensure the adhesion between the photochromic film 2 and the substrate 1. When the thickness of the underlayer exceeds 25 μm, the film configuration including the photochromic film 2 becomes soft, so it is preferable that the thickness is less than 25 μm.

(4) Stress relaxation layer The material of the stress relaxation layer 3 is not particularly limited as long as the stress generated by the shrinkage or the like in the subsequent heating step can suppress the stress generated from the photochromic film 2 side to some extent. The thickness is preferably selected to such an extent that a function of suppressing deformation of the substrate 1 is obtained depending on the material used.

  The stress relaxation layer is not limited as long as it is a film having the ability to cancel or absorb the stress of the photochromic film 2. For example, a material having a high Young's modulus and not easily elastically deformed can absorb the stress of the photochromic layer. In addition, when the stress change of the material for forming the stress relaxation layer and the photochromic layer are substantially equal, the same stress is applied to both the front and back surfaces, so that deformation of the lens substrate is suppressed.

  An example of a particularly preferable material is a material having the same characteristics as the material of the photochromic film 2 with respect to temperature change, that is, a polymer component that is a matrix of the photochromic film 2 has the same characteristics. For example, when the matrix component of the photochromic film 2 is acrylic, the acrylic stress relaxation layer 3 is applied. When the matrix component of the photochromic film 2 is polyurethane, the polyurethane stress relaxation layer 3 is applied. That's fine. If the polymer components constituting the two are substantially the same, the change in shrinkage rate becomes equal, and the deformation under various conditions (for example, temperature and humidity) is offset.

  Moreover, as a particularly preferable material, a material obtained by removing the photochromic dye from the coating liquid used as the material of the photochromic film 2 can be given. In the case of using this material, by setting the thickness to the same level as that of the photochromic film 2, it is possible to generate the same level of stress as that of the photochromic film 2. The range can be easily predicted, and the shape change of the substrate 1 can be effectively suppressed.

  Moreover, the film forming method of the coating liquid for the stress relaxation layer 3 is preferably a spray method or a spin coating method applied only to the second surface 1B of the substrate 1, as with the film forming method of the photochromic film 2. In order to form the film uniformly, spin coating is preferred. The curing conditions of the coating liquid are not particularly limited as in the photochromic film 2, and heat, irradiation with ultraviolet rays, α rays, β rays, γ rays, or the like can be used, or a combination thereof can be used. And is not particularly limited.

  A preferable thickness of the stress relaxation layer 3 when using the above-described acrylic or urethane material or a material obtained by removing a pigment from the material of the photochromic film 2 is 40% or more of the film thickness of the photochromic film 2. It is preferable. On the other hand, when the thickness of the stress relaxation layer 3 exceeds 100% of the thickness of the photochromic film 2, the relaxation effect of the stress relaxation layer 3 exceeds the stress component of the photochromic film 2, resulting in the stress relaxation layer 3. It is also assumed that deformation occurs. Therefore, the upper limit of the thickness of the stress relaxation layer 3 is preferably 120% or less of the thickness of the photochromic film 2.

  Further, an underlying layer (not shown in FIG. 1) may be provided between the stress relaxation layer 3 and the substrate 1, as in the photochromic film 2. The material and film thickness of the underlayer are the same materials as the underlayer when the underlayer is provided on the photochromic film 2, that is, polyurethane resin, polyester resin, epoxy resin, melamine resin, polyurethane acrylate resin, or monomers of these resin components Resins having various functional groups modified on the skeleton can be used. The film thickness may be any thickness that can improve the bonding state between the stress relaxation layer 3 and the substrate 1, and may be 1 μm to 20 μm, preferably 3 μm to 10 μm.

(5) Hard Coat Layer In the plastic lens according to the present embodiment, the material of the hard coat layer 5 formed on the upper surface of the photochromic film 2 is not particularly limited, and known organosilicon compounds and metal oxide colloidal particles The coating liquid consisting of can be used. After applying the coating liquid, the hard coat layer 5 can be obtained by a curing process.
Examples of the organosilicon compound include an organosilicon compound represented by the following general formula (I) or a hydrolyzate thereof.

(R ¹ ) _a (R ³ ) _b Si (OR ² ) _{4- (a + b)} (I)
(In the formula, R ¹ is an organic group having a glycidoxy group, an epoxy group, a vinyl group, a methacryloxy group, an acryloxy group, a mercapto group, an amino group, a phenyl group, etc., and R ² is an alkyl having 1 to 4 carbon atoms. group, an acyl group or an aryl group having 6 to 10 carbon atoms having 1 to 4 carbon atoms, R9 ³ is an alkyl group or an aryl group having 6 to 10 carbon atoms having 1 to 6 carbon atoms, a and b are each 0 or 1 Indicates an integer.)

The alkyl group having 1 to 4 carbon atoms R ^2, for example, a linear or branched methyl group, an ethyl group, a propyl group, a butyl group.
Examples of the acyl group having 1 to 4 carbon atoms R ^2, for example, an acetyl group, a propionyl group, oleyl group and benzoyl group.
Examples of the aryl group having 6 to 10 carbon atoms of R ² include a phenyl group, a xylyl group, and a tolyl group.
The alkyl group having 1 to 4 carbon atoms R ^3, for example, a linear or branched methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group and the like.
Examples of the aryl group having 1 to 10 carbon atoms of R ³ include a phenyl group, a xylyl group, and a tolyl group.

Examples of the metal oxide colloidal particles include tungsten oxide (WO ₃ ), zinc oxide (ZnO), silicon oxide (SiO ₂ ), aluminum oxide (Al ₂ O ₃ ), titanium oxide (TiO ₂ ), and zirconium oxide (ZrO). ₂ ), tin oxide (SnO ₂ ), beryllium oxide (BeO), antimony oxide (Sb ₂ O ₅ ) and the like, and may be used alone or in combination of two or more.

  As a method for applying the coating liquid onto the photochromic film 2, for example, a dipping method, a spin coating method, a spray method, etc. are applied as usual methods. A spin coating method is preferred. In particular, when the hard coat layer 5 is formed as a hard film on the photochromic film 2 and then the other surface, that is, the optical surface of the second surface 1B is formed, a spin coat method that can be applied to one surface is preferable. In addition, when the optical surface of the other surface is formed before the hard film is formed, it is preferable to apply a dipping method that can be applied to both surfaces. Before applying the coating liquid onto the photochromic film 2, chemical treatment with acids, alkalis, various organic solvents, physical treatment with plasma, ultraviolet rays, ozone, etc., and detergent treatment with various detergents are performed. Adhesiveness with the hard coat layer 5 can be improved.

  A primer layer 4 that improves impact resistance may be formed between the photochromic film 2 and the hard coat layer 5. The material for the primer layer 4 is not particularly limited as long as it improves the impact resistance without impairing the adhesion of the hard coat.

(6) Antireflection film In the present invention, the antireflection film 6 may be formed on the hard coat layer 5. The material and formation method of the antireflection film 6 are not particularly limited, and a single layer or a multilayer film made of a known inorganic oxide can be used.
Examples of the inorganic oxide include silicon dioxide (SiO ₂ ), zirconium oxide (ZrO ₂ ), aluminum oxide (Al ₂ O ₃ ), niobium oxide (Nb ₂ O ₅ ), yttrium oxide (Y ₂ O ₃ ), and the like. Can be mentioned.
In addition, a single-layer or multilayer organic antireflection film composed of an organic silicon compound and inorganic fine particles and having a refractive index adjusted according to the type of inorganic fine particles can also be used.

2. Next, a method for manufacturing a plastic lens according to an embodiment of the present invention will be described. FIG. 4 is a flowchart showing each step of the plastic lens manufacturing method according to the present embodiment. In this example, the surface 1A and the second surface 1B of the substrate 1 are formed in advance as optical surfaces made up of, for example, convex surfaces and concave surfaces, and then a photochromic lens is formed using so-called finished lenses in which layers are formed on each surface or both surfaces. Although the case where it manufactures is shown, this invention is not limited to this. As shown in FIG. 4, in the manufacturing method according to the present embodiment, first, as described above, the photochromic film 2 is formed on the first surface 1A of the substrate 1 on which the optical surface is formed (step S1). Thereafter, the stress relaxation layer 3 is formed on the second surface 1B (step S2). As described above, a step of forming a base layer may be added before forming the photochromic film 2 and the stress relaxation layer 3.

  In addition, after forming the coating liquid of the photochromic film 2, it hardens | cures by heating etc., Then, the coating liquid of the stress relaxation layer 3 is formed and hardened | cured by heating etc., but in this heating, the photochromic film 2 of Even if the polymerization proceeds to some extent and shrinkage occurs, the polymerization of the stress relaxation layer 3 also proceeds, so that deformation of the substrate 1 can be suppressed.

  Next, after the stress relaxation layer 3 is formed, other layers provided on the photochromic film 2, such as the primer layer 4, the hard coat layer 5, and the antireflection film 6 are formed (step S3). At this time, the primer layer 7 on the stress relaxation layer 3 may be formed simultaneously with the primer layer 4, and the hard coat layer 8 on the stress relaxation layer 3 may be formed simultaneously with the hard coat layer 5. In this case, the coating liquid for each layer may be formed on both sides by the dipping method and then simultaneously formed by thermal curing or ultraviolet curing. Since the stress relaxation layer 3 has already been formed in any layer heating process or light irradiation process, the shrinkage of the photochromic film 2 due to the generation of heat during heating or light irradiation is suppressed, and the deformation of the substrate 1 is suppressed. can do.

  After passing through the above steps S1 to S3, although not shown in the drawings, a step of forming each layer on the substrate 1 is performed as necessary through a step of forming a material layer that imparts other functions such as water repellency and antifouling properties. finish. In the case of manufacturing as a spectacle lens, the plastic lens according to the present embodiment is completed through an inspection process, for example, by performing peripheral processing such as for spectacle frames.

  The example shown in FIG. 4 shows the case where the present embodiment is applied to a finished lens. However, when the embodiment is applied to a semi-finished lens, the photochromic film 2 is formed after processing and forming only the first surface 1A. Then, before the stress relaxation layer 3 is formed, a process of processing the second surface 1B by optical polishing or the like may be inserted. In any case, the stress relaxation layer 3 is formed before the other heating (or heat generation) step after the photochromic film 2 is formed, so that the photochromic film 2 is thermally contracted as described above. It is possible to suppress the deformation of the substrate 1 with certainty.

3. Examples and Comparative Examples Next, the results of evaluation of photochromic lenses manufactured by applying the plastic lens manufacturing method of the present invention will be described.
(1) Lens Configuration in Examples and Comparative Examples In this example, a lens substrate having a refractive index ne of 1.7 (EYRY, manufactured by HOYA Corporation, product name) and a lens substrate having a refractive index of 1.74 (EYVIA, Examples 1 to 9 (EYRY) and Examples 10 to 19 (EYVIA) provided with a stress relaxation layer 3 after the photochromic film 2 was formed and the stress relaxation layer 3 were prepared. Comparative Examples 1 and 2 (EYRY) and Comparative Examples 3 and 4 (EYVIA) in which the photochromic film 2 was formed without being provided were prepared. An optical surface having a spherical power of -2.00 was formed in advance on a substrate having a refractive index of 1.7, and the lens diameter was 80 mm. An optical surface with a spherical power of −1.25 was formed in advance on a substrate with a refractive index of 1.74, and the lens diameter was 75 mm. The materials and formation conditions of the photochromic film 2 and the stress relaxation layer 3, and the subsequent heat treatment conditions will be described below.

(I) Preparation of photochromic coating solution In a plastic container, 20 parts by mass of trimethylolpropane trimethacrylate, 35 parts by mass of BPE oligomer (2,2-bis (4-methacryloyloxypolyethoxyphenyl) propane), EB6A (polyester oligomer hexa) Acrylate) 10 parts by mass, polyethylene glycol diacrylate having an average molecular weight of 532, 10 parts by mass of radical polymerizable monomer consisting of 10 parts by mass of glycidyl methacrylate, 3 parts by mass of photochromic dye, light stabilizer LS765 (bis ( 1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, methyl (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate) 5 parts by mass, hindered phenolic antioxidant Irga Ox245 (manufactured by Ciba Specialty Chemicals) 5 parts by mass, CGI-184 as a UV polymerization initiator was added (Ciba Specialty Chemicals) 0.6 parts by weight, was thoroughly stirred and mixed.

  6 parts by weight of γ-methacryloyloxypropyltrimethoxysilane (KBM503 manufactured by Shin-Etsu Chemical Co., Ltd.) was added dropwise with stirring to the composition obtained by mixing.

  Thereafter, 0.1 parts by mass of an amine catalyst is further added and mixed, and then defoamed for 2 minutes with a rotation and revolution type stirring deaerator (Sinky AR-250, Inc.), whereby a coating liquid having photochromic properties is obtained. Obtained.

(Ii) Preparation of foundation layer As the foundation layer formed between the substrate 1 and the photochromic film 2, a polyurethane dispersion having an acrylic group introduced into a polyurethane skeleton was prepared.

(Iii) Stress Relaxation Layer Coating Liquid As a material for the stress relaxation layer 3, a coating liquid for forming an acrylic resin film was used. Specifically, in a plastic container, 20 parts by mass of trimethylolpropane trimethacrylate, 35 parts by mass of BPE oligomer (2,2-bis (4-methacryloyloxypolyethoxyphenyl) propane), EB6A (polyester oligomer hexaacrylate) 10 100 parts by mass of a radical polymerizable monomer consisting of 10 parts by mass of polyethylene glycol diacrylate having an average molecular weight of 532 and 10 parts by mass of glycidyl methacrylate, and CGI-184 (manufactured by Ciba Specialty Chemicals) as an ultraviolet polymerization initiator 0.6 Part by mass was added and sufficiently stirred and mixed.
To this mixed solution, 6 parts by weight of γ-methacryloyloxypropyltrimethoxysilane (KBM503 manufactured by Shin-Etsu Chemical Co., Ltd.) was added dropwise with stirring.

(Iv) Formation process of each layer After the 1st surface 1A and 2nd surface B of the board | substrate 1 are cleaned with the volatile solvent which uses isopropanol as a main material, a reflective lens meter (FOCOVISION SR-1) is used. Then, the radii of curvature R1 and R2 of each surface were measured, and converted by assuming the refractive power when the refractive index of each substrate 1 was 1.53.

Next, after cleaning the surface in the same manner, UVO ₃ (ozone) treatment was performed for 1 minute. Further, after washing with pure water, the above-described coating solution for the underlayer was coated by a spin coat method. Thereafter, the base layer was cured and formed by heating at 70 ° C. for 90 minutes.

  Next, the above-mentioned coating solution for the photochromic film 2 was coated on the underlayer by a spin coat method. Then, the thermosetting process was performed and the photochromic film | membrane 2 was formed.

  Next, after the second surface 1B of the substrate 1 is cleaned with a volatile solvent containing isopropanol as a main material, the second surface 1B is formed under the same material, coating conditions and curing conditions as those for the first layer 1A. A stratum was formed.

  Further, the above-described coating liquid for the stress relaxation layer 3 was applied on the base layer of the second surface 1B. At this time, the coating time was fixed at 12.5 seconds, and coating was performed by changing the rotation speed from 500 to 900 rpm. Thereafter, heat treatment was performed to form the stress relaxation layer 3.

  As a heating process after the formation of the stress relaxation layer 3, a heat treatment corresponding to the formation process of the primer layers 4 and 7 and the hard coat layers 5 and 8 was performed. A first heat treatment at 70 ° C. for 90 minutes was performed for the primer layers 4 and 7, and a second heat treatment at 100 ° C. for 60 minutes was performed for the hard coat layers 5 and 8.

(V) Results The curvature radii of the respective substrates 1 in Examples 1 to 19 in which the stress relaxation layer 3 is formed and Comparative Examples 1 to 4 in which the stress relaxation layer is not formed are similarly measured with a reflective lens meter, and the substrate The refractive power of 1 was assumed to be 1.53, the refractive power was converted from the radius of curvature, and the amount of change in refractive power was determined from the difference from the initial refractive power. Further, the film thickness of the photochromic film 2 and the stress relaxation layer 3 is measured by a spectral interference film thickness measurement method in which the film thickness is measured from the difference in refractive index with the base layer, and the ratio of the film thickness of the stress relaxation layer 3 to the film thickness of the photochromic film 2 is measured. (%) Was calculated. The results are shown in Tables 1 and 2. Table 1 shows the results of Examples 1 to 9 and Comparative Examples 1 and 2 using a substrate (EYRY) made of a material having a refractive index of 1.7, and Table 2 made of a material having a refractive index of 1.74. The results of Examples 10 to 19 and Comparative Examples 3 and 4 using (EYVIA) are shown. In addition, the conditions of the rotation speed at the time of application | coating of the coating liquid for the stress relaxation layer 3 are as follows.

Rotational speed 500 rpm: Examples 1, 2, 10, 11
Rotational speed 600 rpm: Examples 3, 4, 12, 13
Number of rotations 700 rpm: Examples 5, 6, 14, 15
Number of rotations 800 rpm: Examples 7, 16, and 17
Rotational speed 900 rpm: Examples 8, 9, 18, 19

  FIG. 5 shows the refractive power measured before two layers are formed on the substrate 1, that is, the refractive power before heating, and after the heat treatment is performed twice after the stress relaxation layer 3 is formed. Further, FIG. 6 shows the amount of change in refractive power with respect to the thickness of the stress relaxation layer 3. In addition, in FIG. 6, the result whose film thickness of the stress relaxation layer 3 is 0 shows Comparative Examples 1-4.

  From the results of FIGS. 5 and 6, it can be seen that although there is variation, the amount of change in refractive power corresponding to the change in the radius of curvature tends to decrease as the thickness of the stress relaxation layer 3 increases. In each example, the thickness of the photochromic film 2 is about 40 μm, while the thickness of the stress relaxation layer 3 is in the range of 17.2 μm to 31.2 μm (the difference from the initial refractive power). When the base material refractive index is assumed to be 1.53 for the sake of convenience, an effect of suppressing it to less than 0.025D is obtained. Moreover, it can be seen from the results in FIG. 6 that the amount of change in refractive power decreases not in proportion to the increase in film thickness of the stress relaxation layer 3, but in inverse proportion. 3 is 15 μm or more (that is, the ratio of the thickness of the stress relaxation layer to the thickness of the photochromic film is approximately 40% or more), it can be seen that the amount of change in refractive power can be suppressed to less than 0.025D.

  In the above embodiment, the photochromic film 2 is set to 40 μm. However, if the film thickness is thinner, for example, 30 μm or 20 μm, the thickness of the stress relaxation layer 3 is not necessarily 15 μm or more. If the film thickness is about 40% or more of the film thickness of 2, it can be easily predicted that the amount of change in refractive power can be sufficiently reduced.

  1. Substrate, 1A. First surface, 1B. Second surface, 2. 2. photochromic film; Stress relaxation layer, 4,7. Primer layer, 5,8. 5. hard coat layer, Antireflection layer

Claims (5)

At least a photochromic film and a hard coat layer are formed on one surface of the plastic lens substrate,
A plastic lens in which a stress relaxation layer for relaxing stress on the substrate caused by thermal deformation of the photochromic film in a lens manufacturing process after forming the photochromic film is formed on the other surface of the substrate.   The difference between the refractive power of the substrate and the refractive power after the heat treatment in the state in which the photochromic film and the stress relaxation layer are formed is 0.025D (when the refractive index of the substrate is assumed to be 1.53) The plastic lens according to claim 1, wherein the plastic lens is less than diopter.   The plastic lens according to claim 1 or 2, wherein a thickness of the stress relaxation layer with respect to a thickness of the photochromic film is 40% or more and 120% or less.   The plastic lens according to any one of claims 1 to 3, wherein a polymer component of the same type as the polymer component constituting the photochromic film is used as the stress relaxation layer. Forming a photochromic film on one surface of the plastic lens substrate;
Forming a stress relaxation layer on the other surface of the substrate to relieve stress on the substrate caused by thermal deformation of the photochromic film in the lens manufacturing process after forming the photochromic film;
A process with heating or heat generation to form another layer on the photochromic film, and
A method for producing a plastic lens, wherein the step of forming the stress relaxation layer is performed before a processing step involving generation of heat or heat for forming the other layer.

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