JP2783499B2 - Plastic lens manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a plastic lens characterized by an annealing step useful for a method for producing a plastic lens such as a polyurethane lens. In particular, the present invention is useful for producing a polyurethane-based lens for correcting astigmatism having a toric surface.

[0002]

2. Description of the Related Art Plastic lenses are manufactured by, for example, a casting polymerization method or an injection molding method. Further, the molded plastic lens is generally provided with a coating called a hard coat layer. After these steps, annealing is preferably performed for the purpose of removing distortion caused by heat applied to the plastic lens. For example, in the case of the cast polymerization method, the plastic lens after the polymerization is released from the mold, and is heated again for annealing in order to remove internal strain generated during the polymerization. As an annealing method, for example, there is a method in which a released lens is placed and heated on a flat plate or a net-like plate with the convex surface facing upward while maintaining the stability of the lens. In the case of an injection molded lens, for example, Japanese Patent Application Laid-Open
As disclosed in Japanese Patent No. 5321, there is an annealing method of immersing the lens in warm water while holding the lens using a hollow lens holder that covers the periphery of the lens.

[0003]

However, in the method using the lens holder disclosed in Japanese Patent Application Laid-Open No. S57-115321, the method for attaching and detaching the holder is complicated, and the immersion operation in warm water takes time. For these reasons, there is a problem that the mass production is not suitable and the cost is high.
In addition, in a mounting method in which a convex surface faces upward on a flat plate or a net-like plate, particularly in the case of a lens such as an astigmatism lens having a deep toric curve, only the lens end surface portion comes into contact with the mounting table, and holding is performed. There was a problem of instability. further,
In the case of a lens having a large change in elastic modulus before and after Tg, such as a polyurethane lens, in addition to instability of holding,
There is also a problem that the lens is easily deformed at the time of annealing heating, which promotes optical distortion, and easily causes a shape transfer property in a mounted state.

Accordingly, an object of the present invention is to easily attach and detach the lens to and from the holder for annealing, to stably hold the lens, and to prevent the lens from being deformed during annealing.
An object of the present invention is to provide a method of manufacturing a plastic lens including an annealing step.

Further, the present invention relates to a polyurethane-based lens which is easy to be attached to and detached from a holder for annealing, can be stably held, and does not deform during annealing, and is easily deformed by heating. An object of the present invention is to provide an annealing method.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a method for producing a polyurethane lens including an annealing step, wherein a polyurethane lens to be annealed is provided on an inner peripheral surface of a cylindrical body opened upward. Annealed on a lens holding device having a tapered lens mounting portion so that the concave surface of the polyurethane-based lens faces upward and the outer peripheral edge of the polyurethane-based lens is in contact with the lens mounting portion. And a method of manufacturing a plastic lens.

Further, the present invention relates to a lens holding device having a lens mounting portion on the inner peripheral surface of a cylindrical body that opens a polyurethane lens upward, wherein the concave surface of the polyurethane lens is directed upward, The present invention relates to a method for annealing a polyurethane-based lens, wherein the outer peripheral edge of the lens is placed so as to be in contact with the lens placing portion and annealing is performed.

[0008] The term "plastic lens to be annealed" in the present invention includes any plastic lens that remains optically distorted when commercialized without annealing. Therefore, the shape, material, molding method, and coating method of the lens are not particularly limited as long as the plastic lens remains optical distortion when commercialized without annealing. Such a plastic lens includes, for example, a plastic lens molded by a casting polymerization method, an injection molding method, or the like, or a plastic lens after a hard coat layer is coated and cured on a plastic lens already molded, or a heating step of performing a dyeing treatment. And a plastic lens after the application.

Generally, the shape of a plastic lens is as follows:
In addition to a meniscus shape in which one surface is concave and one surface is convex, there is a double-sided concave shape, a double-sided convex shape, a concave surface in one surface, a flat surface in one surface, a convex surface in one surface, and a flat surface in one surface. However, the plastic lens manufactured by the method of the present invention is a meniscus lens having one concave surface and one convex surface. In particular, it is possible to satisfactorily anneal a meniscus-shaped plastic lens whose concave surface is a toric surface and whose convex surface is a spherical surface or an aspheric surface. Also,
Also includes semi-finished lenses.

As a material of the plastic lens, a polyurethane lens which is particularly susceptible to deformation by heat can be exemplified. In the method and annealing process of the present invention, the polyurethane lens, for example, a polyisocyanate, a polymer polyol and / or a monomer mixture containing polythiol [for example, Japanese 63-4
No. 6213 , JP-A-3-284715]. Further, it goes without saying that a polyurethane-based lens to which a third component is arbitrarily added in addition to the above components according to the purpose can be produced by the production method of the present invention.

[0011] As the hard coat layer provided on the plastic lens to be subjected to annealing, is preferably one composed mainly of organic silicon compound, R ¹ _a R ² _b S
An organosilicon compound represented by i (OR ³ ) _4-ab and / or a hydrolyzate thereof can be used. Where R ¹ ,
R ² is an alkyl group, an alkenyl group, an aryl group, or a hydrocarbon group having a halogen group, a glycidoxy group, an epoxy group, an amino group, a mercapto group, a methacryloxy group or a cyano group, and R ³ has 1 carbon atom. To 8 are an alkyl group, an alkoxyalkyl group, an acyl group, a phenyl group, or an allylalkyl group, and a and b are 0 or 1. In addition, colloidal fine metal oxides (eg, silica, antimony oxide,
Zirconium oxide, titanium oxide, tin oxide, etc.), metal alkoxide, curing agent, etc., depending on the purpose.

In the case of a plastic lens obtained by a polymerization method, examples of the polymerization method include a thermal polymerization method and a polymerization method using light rays including ultraviolet rays and visible rays. As for the molding method of the lens, casting molding, injection molding, injection compression molding, pressure molding and the like can be mentioned. However, a preferred molding method is cast molding. As a lens type,
Metal, glass, ceramic, plastic and the like can be used. The upper mold and the lower mold having a lens cavity space formed by a toric surface and a spherical or aspherical surface are formed by a toric surface and a spherical or aspherical surface. Furthermore, the mold release process after molding differs depending on the manufacturing method.However, in the casting method, the sealing material is removed, and a wedge is driven between the lower mold and the molded lens to separate them from each other. There is a method of removing the lens by peeling the upper mold, or alternately immersing the lens in cold water and hot water, and releasing the mold by applying a heat shock due to a temperature difference or the like. In the injection molding method, a method of directly ejecting from a mold is generally used.

In the manufacturing method and the annealing method of the present invention,
A “lens holding device having a tapered lens mounting portion provided on the inner peripheral surface of a cylindrical body that is opened up and down” is used.
The lens holding device will be described with reference to the plan view of FIG. 1 and the cross-sectional view (XX) of FIG. However, the lens holding device shown in FIG. 1 is an example, and the present invention is not limited to this. Reference numeral 1 denotes a lens holding device, and the lens holding device 1 is a cylindrical body that opens vertically. The inner surface of the lens holding device 1 has a tapered lens mounting portion 2. The angle of the tapered surface of the lens mounting portion 2 is set in consideration of the radius of curvature of the convex surface of the held lens. In addition, the angle of the tapered surface is preferably such that a thread chamfering process is performed from the viewpoint of contact generated during handling of the lens, safety, and the like.

FIG. 3 shows another embodiment of the lens holding device used in the present invention. The lens holding device 11 shown in FIG. 3 is provided with two stages of lens mounting portions, and can anneal two lenses simultaneously. That is, the lens holding device 11
Is a cylindrical body that is opened up and down, provided with two lens mounting portions 12A and 12B whose upper die side provided on the inner peripheral surface in the axial direction is larger than the lower side, and these lens mounting portions are , And each has a tapered lens mounting surface that supports the outer peripheral edge of the plastic lens. Thus, the lens holding device used in the present invention is:
It can have one or more lens mounts,
The number of lens mounting portions can be determined as appropriate.

Further, as shown in FIG. 3, the lens holding device of the present invention can have a concave portion 15 for taking out a lens. That is, one end of the peripheral wall portion of the lens holding device 11 is open to the upper end opening of the lens holding device, and the other end is located at the same height position or lower than the lowermost lens mounting portion so that the inside and outside of the lens holding device are located. A plurality of lens removal recesses 15 to be communicated
Is provided. However, the concave portion for taking out the lens may not be provided, or one or two or more concave portions may be provided. Further, it is preferable that two take-out recesses are formed at opposing positions of the storage recess. The shape of the concave portion for taking out the lens is set to such a size that a human finger can enter, and the plastic lens can be taken out with the finger. The height from the lower end side opening surface of the lens holding device to the lowermost lens mounting portion is such that when the plastic lens is mounted on the lens mounting portion with the concave surface facing upward, the lens convex surface (lower surface) is set. The height which does not protrude from the lower end side opening surface is set in consideration of the radius of curvature of the convex surface. The plastic lenses 13A and 13B to be annealed
Each of the tapered lens mounting portions 12A and 12A
B. The plastic lens is placed so that the peripheral edge lower surface 14 is supported by the lens placing portion. This state is shown in the sectional explanatory view (YY) of FIG.
FIG. 4 does not show the plastic lens 13B and the lens removing recess 15 for convenience. The concave side of the plastic lens 13A is held in a non-contact state.

The lens holding device used in the present invention is preferably made of, for example, an aluminum alloy in consideration of lightness and heat resistance. However, plastics, ceramics, metals other than aluminum, and the like may be used as long as the material takes into account lightness and heat resistance in a predetermined temperature range.

The plastic lens to be annealed placed on the lens holding device is annealed under predetermined conditions. The annealing conditions depend on whether the plastic lens to be annealed is molded and released or coated, and furthermore, depending on the plastic lens material, molding conditions, coating material and curing conditions, etc. Change. For example, in the case of a polyurethane lens, the annealing temperature and time can be, for example, in the range of 20 ° C. to 130 ° C., and the annealing time can be in the range of 30 minutes to 12 hours.

[0018]

The present invention will be described in more detail with reference to the following examples. Example 1 Molding of lens 3 to be annealed 100 parts by weight of m-xylene diisocyanate, 142 parts by weight of pentaerythritol tetrakis 3-mercaptopropionate, 6 parts by weight of di-n-butyl phosphate and 0.25 of dibutyltin diurarate Parts by weight and 0.5 parts by weight of 2- (2'-hydroxy-5'-t-octylphenyl) benzotriazole as an ultraviolet absorber were mixed and thoroughly stirred, and then degassed under a vacuum of 1 mmHg for 60 minutes. Was. Next, spherical power +3.00 deopters (D), astigmatism power +1.00 optometry (D), lens outer diameter 70
Φ, to obtain a prescription lens with a center thickness of 2.0 mm, prepare upper and lower glass lens molds, assemble a lens mold with a tape-type resin gasket, inject the mixture into the mold, The temperature was continuously raised from 25 ° C. to 120 ° C. over 20 hours, and further maintained at 120 ° C. for 2 hours to perform polymerization. The tape was removed, a wedge was driven between the lower mold and the molded lens to separate them, and the upper mold was peeled from the lens to take out the lens.

Annealing Step Next, the lens obtained in the releasing step was held in a device similar to the lens holding device shown in FIG. The lens holding device is made of an aluminum alloy, and the lens receiving recess has an inner diameter of 6 mm.
It was 8 to 75Φ. The inclination of the tapered surface of the lens mounting part is 45 degrees with respect to the plane. The lens was annealed under the condition of 20 ° C. to 115 ° C. in such a state. The obtained lens had no optical distortion and exhibited excellent lens properties.

Example 2 Lenses 13A and 13B to be Annealed Molded polyurethane lens monomers 484 parts by weight of m-xylene diisocyanate, 305 parts by weight of pentaerythritol tetrakis 3-mercaptopropionate, 90 parts by weight of monothioglycerol, and dibutyltin 0.3 parts by weight of diurarate 0.5 parts by weight of 2- (2'-hydroxy-5'-t-octylphenyl) benzotriazole as an ultraviolet absorber was mixed and sufficiently stirred, and then 1 mmH
Degassed under vacuum of 60 g for 60 minutes. Next, the spherical power-
3.00 ヂ optry (D), astigmatic power -1.00 ヂ optry (D), lens outer diameter 80 mmφ, center thickness 1.
To obtain an 8 mm prescription lens, upper and lower glass lens molds are prepared, a lens mold is assembled with a resin gasket, and the mixed solution is poured into the mold.
℃ continuously over 20 hours, and further increased to 120 ℃
For 2 hours to carry out polymerization to mold the lens 13A. Apart from this, a lens 13B was molded in the same manner as described above except that the lens outer diameter was 75 mmφ. The gasket was removed, a wedge was driven between the lower mold and the molded lens to separate them, and the upper mold was peeled from the lens to take out the polyurethane lenses 13A and 13B.

Annealing Step Next, the lens obtained in the releasing step is inserted and arranged in an apparatus similar to the lens holding apparatus shown in FIG.
Annealing was performed at 120 ° C. The lens holding device is made of an aluminum alloy and has a dimension of 86 mm in outer diameter.
φ, the inner diameter of the upper opening was 81 mmφ, and the inner diameter of the lower opening was 69 mmφ. The angle of the tapered surface was 45 degrees with respect to the plane. The obtained lens had no optical distortion and exhibited excellent lens properties.

Example 3 Formation of Hard Coat Layer To a glass container equipped with a magnetic stirrer, 142 parts by weight of γ-glycidoxypropylmethoxysilane were added, and while stirring, 1.4 parts by weight of 0.01 N hydrochloric acid were added. And 32 parts by weight of water. After completion of the dropwise addition, the mixture was stirred for 24 hours to obtain a hydrolyzate of γ-glycidoxypropyltrimethoxysilane. Next, stannic oxide zirconium monoxide composite sol (methanol dispersion, total metal oxide 3
1.5% by weight, average particle size 10 to 15 micron) 4
60 parts by weight, 300 parts by weight of ethyl cellosolve, 0.7 part by weight of a silicone-based surfactant as a lubricant, and 8 parts by weight of aluminum acetylacetonate as a curing agent, a hydrolyzate of the above-mentioned γ-glycidoxypropyltrimethoxysilane After the mixture was sufficiently stirred, filtration was performed to prepare a coating liquid. After thoroughly washing the plastic lens (polyurethane-based lens obtained in Example 1) treated with an aqueous alkali solution, the plastic lens is immersed in the coating solution, and dipped (with a pulling speed of 14 cm / min). After the immersion, the plastic lens was heated at 130 ° C. for 2 hours to form a cured film (hard coat film). Annealing Step Since the lens having the hard coat layer showed some deformation and distortion due to heating by curing, the lens was annealed in the same manner as in Example 1 using the lens holding device of FIG. The annealing condition at this time is 80 ° C. to 120 ° C.
Time. The resulting lens exhibited excellent lens physical properties due to deformation and optical distortion.

[0023]

According to the method for producing a plastic lens and the annealing method of the present invention, it is possible to easily obtain a plastic lens made of polyurethane for astigmatism correction and having excellent optical characteristics with suppressed optical distortion. This method is simple and suitable for mass production, and can provide an inexpensive plastic lens made of polyurethane for astigmatism correction.

[Brief description of the drawings]

FIG. 1 is a plan view of a lens holding device used in the present invention.

FIG. 2 is a sectional view taken along line XX of the lens holding device shown in FIG.

FIG. 3 is an explanatory perspective view of a lens holding device used in the present invention.

FIG. 4 is a sectional view taken along the line YY of the lens holding device shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 11 Lens holding device 2, 12A, 12B Lens mounting part 3, 13A, 13B Lens 14 Lens peripheral edge lower surface 15 Lens recess

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B29C 71/02 B29C 35/02-35/14 C08J 7/00 301 G02B 1/04

Claims (11)

(57) [Claims] 1. A method of manufacturing a polyurethane lens including an annealing step, wherein a polyurethane lens to be annealed includes a tapered lens mounting portion provided on an inner peripheral surface of a cylindrical body opened upward. A plastic lens characterized in that the lens is placed and annealed with the concave surface of the polyurethane lens facing upward and the outer peripheral edge of the polyurethane lens is in contact with the lens mounting portion on the lens holding device having the lens. Manufacturing method. 2. The method according to claim 1, wherein the polyurethane lens is mounted on each lens mounting portion of the lens holding device having at least two lens mounting portions. 3. One end of the peripheral wall portion of the lens holding device is open to the upper end opening of the lens holding device, and the other end is located at the same height position or below the lowermost lens mounting portion. 3. The manufacturing method according to claim 1, wherein one or two or more lens taking-out recesses for communicating the inside and the outside are provided. 4. The manufacturing method according to claim 3, wherein two take-out recesses are formed at opposing positions of the storage recess. 5. A polyurethane lens is placed on a lens holding device having a lens mounting portion on an inner peripheral surface of a cylindrical body opened upward, with the concave surface of the polyurethane lens facing upward.
A method of annealing a polyurethane-based lens, comprising mounting the polyurethane-based lens so that an outer peripheral edge thereof is in contact with the lens-mounting portion and annealing the lens. 6. The annealing method according to claim 5, wherein the polyurethane lens has a toric surface on a concave surface, a spherical surface or an aspheric surface on a convex surface, and has a meniscus shape. 7. The annealing method according to claim 5, wherein the polyurethane lens is a lens coated and cured with a hard coat. 8. The annealing method according to claim 5, wherein the lens holding device has a tapered lens mounting portion provided on an inner peripheral surface of a cylindrical body that is opened up and down. 9. The annealing method according to claim 5, wherein a polyurethane-based lens is mounted on each lens mounting portion of the lens holding device having at least two lens mounting portions. 10. A peripheral wall portion of the lens holding device, one end of which is open to an upper end opening of the lens holding device and the other end is located at the same height position or below the lowermost lens mounting portion. 10. One or more of the claims 5 to 9, wherein one or two or more lens taking-out recesses for communicating the inside and the outside are provided.
The production method according to the paragraph. 11. The manufacturing method according to claim 10, wherein two take-out recesses are formed at opposing positions of the storage recess.