JPH08254603A - Half dimming plastic lens and manufacture thereof - Google Patents

Abstract

PURPOSE: To maintain a bright-visional and easily visible state of an object without reducing visible light transmissivity of a lens under normal conditions by forming ultraviolet absorption layers on both surfaces of a lower part of half dimming plastic lens. CONSTITUTION: In this manufacture, a lower part 5 of a dimming plastic lens 2 is immersed for 5 to 30min in a solution obtained by dissolving an ultraviolet- absorbing agent in hot water of 70 to 90 deg.C to deposit the agent on the surfaces of the lower part 5 of the lens 2 and then, this lens 2 is taken out of the solution and dried to manufacture a half dimming plastic lens 1 having ultraviolet absorption layers 6 on its lower part 5. Accordingly, even when ultraviolet rays are incident on the lower part 5 of the lens 1, the rays are shielded by the ultraviolet absorption layers 6 and the lower part 5 is inhibited from being discolored by the effect of the absorption layers 6 to maintain its visible light transmissivity at about 90%. Also, since the whole surface of the lens 1 does not uniformly turn dark in color when ultraviolet rays are incident on the lens 1, this lens 1 has novelty that theretofore can not be attained and its fashonableness is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a half dimming plastic lens used as a lens for sunglasses and having a function of not causing partial discoloration, and a method for manufacturing the same.

[0002]

2. Description of the Related Art A material obtained by adding a photochromic dye to a main raw material plastic, and optionally adding auxiliary materials such as a pigment agent, a stabilizer, a filler and an antistatic agent, and mixing and kneading these. The lens produced by injection molding or compression molding using is called a dimming plastic lens that changes from a nearly colorless state to a slightly darker brown or gray color when exposed to ultraviolet light, and is commonly used in sunglasses. There is.

[0003]

However, in the above-mentioned photochromic plastic lens, the entire surface of the lens is uniformly discolored when exposed to ultraviolet rays, and the transmittance of visible light is remarkably reduced. There was a drawback that was hard to see. In addition, it lacked novelty and lacked fashion. Therefore, the upper part of the lens discolors when exposed to ultraviolet light, and the transmittance of visible light is significantly reduced to eliminate glare, while the lower part of the lens does not discolor even when exposed to ultraviolet light. Maintains the transmittance of so that the objects can be seen well. Furthermore, it aims to enhance the novelty of the lens and improve the fashionability.

[0004]

[Means for Solving the Problem] A main raw material plastic, that is, cellulose acetate propionate is added with a spirooxazine compound, and auxiliary materials such as a stabilizer, a filler, and an antistatic agent are added if necessary. Add an appropriate amount. A light-modulating plastic lens having a photochromism phenomenon in which the entire lens is thinly colored is manufactured by means of injection molding or compression molding using a material obtained by mixing and kneading these. Further, an ultraviolet absorbing layer is formed below the light control plastic lens described above.

[0005]

[Function] The upper part of the lens is discolored when exposed to ultraviolet rays outdoors and the transmittance of visible rays is remarkably reduced.
The lower part of the lens has a function of maintaining the transmittance of visible light without being discolored when exposed to ultraviolet rays.

[0006]

EXAMPLES The following will describe examples in detail with reference to the drawings. The half-dimming plastic lens 1 according to the present invention is mainly used for sunglasses, and has a uniform thickness and does not have a vision correction function. (FIGS. 1 and 2),
There is a prescription lens (FIGS. 3 and 4) having a vision correction unit 2 for nearsightedness / diopia or bifocals, both of which are manufactured in a substantially circular shape. An ultraviolet absorbing layer 6 is formed on the lower part 5 (about half the lower part) of the half-dimming plastic lens 1.
On both sides, sometimes only on one side. The half-dimming plastic lens 1 is made of the main plastic material, that is,
An appropriate amount of auxiliary materials such as stabilizers, fillers and antistatic agents which are usually used in cellulose acetate propionate (manufactured by Eastman Chemical Co.) are added as necessary, and a spirooxazine compound is added.
A circular dimming plastic lens 2 having a photochromism phenomenon in which the entire lens is thinly colored is manufactured by means of injection molding or compression molding using a material in which these are well mixed and kneaded. When the light control plastic lens 2 is exposed to ultraviolet rays, the light control plastic lens 2 changes from a nearly colorless state to a slightly darker color such as a brown type or a gray type, and the visible light transmittance decreases from about 90% to about 20% to 30%. If no ultraviolet ray is applied, the visible light transmittance is restored from about 20% to 30% to about 90% of the original.

Next, an ultraviolet absorber such as BPI
(UV-400) or UV-1008 (benzophenone type) manufactured by Mitsui Toatsu Co., Ltd. is dissolved in hot water at 70 ° C to 90 ° C, and the lower part 5 of the light control plastic lens 2 manufactured as described above is placed in this solution. Soak for 5 to 30 minutes. In this way, the ultraviolet light absorber adheres to both surfaces of the lower portion 5 of the light control plastic lens 2, so that the half light control plastic lens 1 having the ultraviolet light absorption layer 6 can be obtained by taking it out and drying it. Due to the effect of the ultraviolet absorbing layer 6, the lower portion 5 of the half-dimming plastic lens 1 maintains a visible light transmittance of about 90% even when exposed to ultraviolet rays. Next, the addition amount of the main raw material and the auxiliary material will be exemplified. Cellulose acetate / propionate 100 parts by weight Spirooxazine-based compound Appropriate amount Pigment Appropriate amount if necessary Stabilizers Appropriate amount if necessary Filler Appropriate amount if necessary Antistatic agent Appropriate amount as necessary UV absorber BPI (UV-400) 0 0.01 to 0.5 parts by weight It should be noted that the work of immersing the light control plastic lens 2 in the ultraviolet absorbent solution and the work of taking it out may be manual or automatic by a robot machine. If one surface of the lower portion 5 of the light control plastic lens 2 is covered with a release paper or the like, the ultraviolet absorbent will adhere to only one surface, and the ultraviolet absorption layer 6 can be formed on only one surface. Further, a hard coat is applied on both sides of the half dimming plastic lens 1 as needed, and the hard coat is at the stage of the dimming plastic lens 2 (pretreatment) or at the stage of becoming the half dimming plastic lens 1. You can go.

[0008]

According to the half dimming plastic lens 1 of the present invention, since the ultraviolet absorbing layer 6 is formed in the lower portion 5 of the lens, ultraviolet rays are blocked by the ultraviolet absorbing layer 6 and do not change color. Therefore, the visible light transmittance in the normal state is about 90%, and there is an effect that a bright and easily visible state is maintained. Further, when the ultraviolet rays hit the upper part 4 of the lens, it changes from a nearly colorless state to a slightly darker color such as a brown type or a gray type, and the visible light transmittance is from about 90% to
% To about 30%. Therefore, the glare is naturally eliminated, and the effect of protecting the eyes is achieved. Furthermore, when ultraviolet rays hit, the entire surface of the lens does not become a dark color uniformly,
It has unprecedented novelty and improves fashionability. The UV absorbing layer 6 can be formed simply by dissolving the UV absorber in warm water, immersing the lower part 5 of the light control plastic lens 2 in this solution and drying it. Therefore, the half light control plastic lens 1 can be manufactured easily and inexpensively. There is an effect that can be done.

[Brief description of drawings]

FIG. 1 is a front view of a half dimming plastic lens (without a visual acuity correction unit).

FIG. 2 is a vertical cross-sectional view of a central portion of a half-dimming plastic lens (without a visual acuity correction unit).

FIG. 3 is a front view of a half dimming plastic lens (with a visual acuity correction unit).

FIG. 4 is a vertical cross-sectional view of a central portion of a half-dimming plastic lens (with a visual acuity correction unit).

FIG. 5 is an enlarged cross-sectional view of a lower portion of the half light control plastic lens.

[Explanation of symbols]

 1 Half dimming plastic lens 2 Dimming plastic lens 3 Visual correction part 4 Upper part 5 Lower part 6 Ultraviolet absorption layer

Claims (2)

[Claims] 1. A lower portion 5 of the light control plastic lens 2.
A half-dimming plastic lens characterized in that an ultraviolet absorbing layer 5 is formed on the. 2. An organic photochromic compound commonly used in cellulose acetate propionate,
Light control plastic in which the entire lens is thinly colored by means of injection molding or compression molding, using a material in which an appropriate amount of stabilizers, fillers, antistatic agents, pigments, etc. are added and mixed and kneaded. The lens 2 is manufactured, and the lower part 5 of the light-modulating plastic lens 2 is dipped in a solution of an ultraviolet absorber such as BPI (UV-400) or UV-1008 (benzophenone type) dissolved in warm water, and dried. A method of manufacturing a half dimming plastic lens, which comprises forming an ultraviolet absorbing layer 6 on a lower portion 5 of the dimming plastic lens 2.