JP2019082631A - Resin layer forming method - Google Patents

Abstract

To provide a resin layer forming method that can reduce the dimensions of liquid pooling formed in an outer edge part, while ensuring a desired thickness of the resin layer.SOLUTION: According to the present invention, there is provided a resin layer forming method for forming a resin layer on at least one face of a lens substrate for a plastic lens, the resin layer forming method including the steps of: applying a coating liquid containing an ultraviolet curable resin to at least one face of the lens substrate for a plastic lens; heating the coating liquid on the lens substrate; and irradiating the coating liquid with an ultraviolet ray to cure the ultraviolet curable resin, thereby obtaining a resin layer.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for forming a resin layer, and more particularly, to a method for forming a resin layer on at least one surface of a lens substrate for a plastic lens.

  In some cases, a resin layer is provided on the surface of a plastic lens used for glasses and the like to provide an additional function to the plastic lens. As a method of forming such a resin layer, there is a method of applying and curing a coating liquid as a raw material of the resin layer on the surface of a plastic lens substrate to be processed into a plastic lens.

  In such a forming method, for example, as shown in Patent Document 1, a coating solution containing an ultraviolet curable resin is applied on the surface of a lens substrate by a spin coating method, and then the coating solution is irradiated with ultraviolet rays and the like for coating. The liquid is cured to form a resin layer which imparts a specific function such as scratch resistance to the plastic lens on the surface of the lens substrate.

JP, 2005-343119, A

  A resin layer for imparting general functions such as scratch resistance is sufficient with a thickness of about 3 μm, but with a resin layer or the like for imparting special functions to a lens, the thickness is relatively thick at 5 μm or more Thickness may be required. For example, in a resin layer that imparts a light control function to a lens, a thick thickness of about 40 μm may be required.

  In the case of forming such a relatively thick resin layer, the coating solution is thicker than 5 μm, and in the case of providing a light control function, 40 μm or more on the lens substrate surface. It needs to be applied.

  However, when a coating solution applied with such a thickness is cured to form a resin layer by a method of the prior art, when the lens substrate is rotated to make the thickness of the coating solution uniform, The problem that the thickly applied coating liquid is moved to the outer edge portion of the lens substrate and the size of the annular thick portion (so-called "liquid pool") formed in the outer edge portion and visually recognized in a ring shape becomes large. was there.

  Also, if the rotational speed of the lens substrate is increased to reduce the size of such a liquid pool, a large amount of coating solution is blown away from the lens substrate, and the necessary amount of coating solution is formed on the lens substrate. There is also a problem that all resin layers of desired thickness can not be obtained.

  The present invention has been made in view of such a point, and a resin layer forming method capable of reducing the size of a liquid pool formed at the outer edge while securing a desired thickness of the resin layer It is intended to be provided.

According to the invention
A resin layer forming method for forming a resin layer on at least one surface of a lens substrate for a plastic lens,
Applying a coating solution containing an ultraviolet curable resin to at least one surface of a lens substrate for a plastic lens;
Heating the coating solution on the lens substrate;
Irradiating the coating solution with ultraviolet light to cure the ultraviolet curable resin to obtain the resin layer;
A method of forming a resin layer is provided.

  According to such a configuration, after the application of the application liquid, the application liquid is heated, and a part of the components and the like contained in the application liquid is volatilized, so the flowability of the application liquid decreases and moves to the outer edge This becomes difficult, and in forming the resin layer, it is possible to suppress the increase in the size of the liquid pool while securing the thickness of the coating liquid.

  According to the present invention, there is provided a resin layer forming method capable of reducing the size of a liquid pool formed at the outer edge while securing a desired thickness of the resin layer.

It is a flowchart which shows the process of the resin layer formation method of preferable embodiment of this invention. It is typical drawing explaining the arrangement | positioning method of the coating liquid in application | coating step S1 of the resin layer formation method of FIG. It is typical drawing explaining arrangement | positioning of the lens base material in heating step S2 of the resin layer formation method of FIG. It is a schematic diagram explaining the liquid pool on a lens base material.

  Hereinafter, a resin layer forming method according to a preferred embodiment of the present invention will be described with reference to the drawings.

  The resin layer forming method of the present embodiment is a resin layer forming method for forming a resin layer having a light control function on at least one surface of a lens base for a plastic lens used for eyeglasses and the like.

  As shown in FIG. 1, in the resin layer forming method of the present embodiment, first, in step S1, ultraviolet light is applied to at least one surface (coated surface 1a) of the substantially circular lens substrate 1 for plastic lenses. An application step of applying a coating solution containing a curable resin is carried out.

  The coating solution may be applied to the lens substrate by dip coating or spin coating. However, in the resin layer forming method of the present embodiment, spin coating using a spin coater is selected.

  In the resin layer forming method of the present embodiment, the coating liquid is applied to the convex surface of the lens substrate, but the surface to which the coating liquid is applied may be concave. If it is a convex surface, the solution elimination effect can be obtained better.

  In spin coating in the resin layer forming method of this embodiment, spin coating is performed with the surface (coated surface) of the lens substrate facing in the horizontal direction, that is, with the optical axis oriented in the horizontal direction (longitudinal placement). went. However, spin coating may be performed with the surface (coated surface) of the lens substrate facing upward in the vertical direction, that is, with the optical axis oriented in the vertical direction (horizontal placement).

  As a lens substrate for a plastic lens used in the present embodiment, for example, a copolymer of methyl methacrylate and one or more other monomers, and a copolymer of diethylene glycol bisallyl carbonate and one or more other monomers And copolymers of polyurethane and polyurea, polycarbonate, polystyrene, polyvinyl chloride, unsaturated polyester, polyethylene terephthalate, polyurethane, polythiourethane, sulfide resin utilizing ene-thiol reaction, vinyl polymer containing sulfur, etc. . Although a urethane type is preferable, it is not limited to these.

  The plastic lens may be any of a biconvex lens, a biconcave lens, a planoconvex lens, a planoconcave lens, a convex meniscus lens, and a concave meniscus lens. Although the lens diameter is not particularly limited, it is preferable to use a lens with a diameter of about 50 to 100 mm because an excessively large lens requires a long time for the coating process. In order to effectively prevent liquid accumulation by centrifugal force, it is preferable that the lens has a convex surface. Moreover, in order to hold | maintain a coating liquid stably on a lens convex surface, it is preferable that a lens convex surface is a curved surface of -8 to +8.

  The coating liquid used in the resin layer forming method of the present embodiment is a coating liquid containing at least an ultraviolet curable resin component and a solvent.

  A photo cationic polymerization initiator was used as the ultraviolet curable resin component contained in the coating solution. As a photocationic polymerization initiator, a sulfonium salt, an iodonium salt, a diazonium salt etc. are mentioned. Among these, the photocationic polymerization initiator is preferably a sulfonium salt, more preferably diphenyl-4- (phenylthio) phenylsulfonium hexafluorophosphate or diphenyl-4- (phenylthio) phenylsulfonium hexafluoroantimonate. is there.

  Among these, a compound having a (meth) acryloyl group or a (meth) acryloyloxy group as a radically polymerizable group is preferable from the viewpoint of easy availability and good curability. In addition, the said (meth) acryloyl shows both acryloyl and methacryloyl.

  In the resin layer forming method of the present embodiment, a method of arranging the coating liquid 4 in a spiral shape on the coating surface of the lens substrate 1 by the dispenser nozzle 2 in the coating step S1 is adopted (FIG. 2). The method of arranging the coating solution in a spiral on the coating surface is preferable because it can improve the uniformity of coating regardless of the viscosity of the coating solution. In the resin layer forming method of the present embodiment, for example, the coating liquid is helically arranged by a method as described in JP-A-2009-285978.

  In the resin layer forming method of this embodiment, the dispenser nozzle 2 that discharges the coating liquid of the spin coater on the coated surface of the lens substrate rotating at a medium speed (for example, about 200 rpm) is shown by an arrow in FIG. The coating liquid is spirally disposed on the application surface 1 a of the lens substrate 1 by moving the lens substrate 1 radially outward from the center of the lens substrate 1 or radially inward from the peripheral edge of the lens substrate 1. Ru. The coating solution to be disposed may be in a state of being in contact with the coating solution adjacent in the radial direction, or in a state of being spaced apart. The spirally arranged coating solution is then smoothed by flowing radially. The amount of the coating liquid to be disposed is set to an amount that results in a resin layer having a desired thickness when the coating liquid is cured.

  After the placement of the coating solution is completed, the lens substrate 1 is rotated at a rotational speed (for example, about 300 rpm) higher than that at the time of the placement of the coating solution, thereby spirally placing the thickness of the coating solution flowing in the radial direction. It is preferable to make the height more uniform.

  Subsequently, heating step S2 which heats the application liquid on the application side of lens substrate 1 is carried out. In this heating step, the coating solution disposed in a spiral shape on the coated surface of the lens substrate 1 is heated by the IR heater.

  Specifically, in this heating step, for example, as shown in FIG. 3, the lens substrate 1 is vertically disposed with its optical axis facing in a substantially horizontal direction, and the coated surface of the lens substrate 1 is 1a is made to face the planar radiation portion of the IR heater 6, and infrared rays from the IR heater 6 heat the coating liquid 2 spirally arranged on the coated surface and flowing in the radial direction for a predetermined time. Also during heating by the IR heater 6, the lens substrate 1 is rotated at a low speed (for example, about 50 rpm) about the optical axis.

  In the present embodiment, the set temperature of the IR heater 4 is set to about 180 to 200 degrees Celsius so that the ambient temperature is 150 degrees to 170 degrees Celsius or more.

  By this heating, a part of the solvent and the like in the coating liquid is volatilized, the viscosity of the coating liquid is increased, and the fluidity is reduced.

Next, a cooling step S3 of cooling the coating liquid 4 on the coated surface of the lens substrate 1 heated in the heating step to a normal temperature (room temperature) is performed.
In this step, the coating liquid 4 on the coated surface 1a of the lens substrate 1 is cooled to a normal temperature (about 20 to 30 degrees Celsius) by rotating the lens substrate at a low speed (for example, about 50 rpm) in an atmosphere at room temperature. Air cool down.

Next, the lens substrate 1 having the coating solution cooled to room temperature in the cooling step is rotated at high speed to perform a high-speed rotation step S4 to make the coating solution on the application surface 1a of the lens substrate 1 more uniform in thickness. Be done. In this high-speed rotation step S4, the thickness of the coating liquid 4 on the lens substrate 1 is made more uniform by centrifugal force by rotating the lens substrate 1 at high speed (for example, about 1000 rpm) by a spinner or the like. At the same time, in some cases, the excess coating solution 4 is blown out of the lens substrate 1.
The high speed rotation step S4 may be performed prior to the cooling step S3. Furthermore, a resin layer forming method which does not perform this high-speed rotation step S4 is also possible.

  Next, a UV curing step S5 is carried out to obtain a resin layer by curing the UV curable resin contained in the coating solution by irradiating the coating solution having a uniform thickness in the high-speed rotation step S4 with ultraviolet rays.

  In this UV curing step S5, while rotating the lens substrate at a low speed (for example, about 50 rpm), the coating solution 1a is irradiated with the UV light generated by the UV lamp as in the UV curing step in the prior art. The coating liquid (specifically, the ultraviolet curable resin in the coating liquid) on the coated surface 1 a of 1 is cured to obtain a resin layer on the lens substrate 1.

Further, a heat treatment step S6 is performed in which heat is applied to the resin layer obtained in the UV curing step S5 to further cure the resin layer, and the resin layer forming method of the present embodiment is completed.
According to such a method, it is possible to form a resin layer having a thickness of 20 to 40 μm while suppressing the width of the liquid pool to 10 mm or less.

Subsequently, examples of the present invention will be described.
In the present example, a lens base having an outer diameter of 75 mm for plastic lenses was used as the lens base.

  First, as a coating step, after the lens substrate is placed vertically and the lens substrate is rotated at 200 rpm for one second about the optical axis, the nozzle for applying the coating liquid while further rotating at 200 rpm is The coating was moved radially outward from the center on the coated surface of the lens substrate, and 1 to 2 g of the coating solution was spirally disposed on the coated surface. Thereafter, the lens substrate continued to rotate at 200 rpm for 12 seconds, and then at 300 rpm for 3 seconds.

  The composition of the coating solution is Compoceran SQ Series (manufactured by Arakawa Chemical Industries, Ltd.), propylene glycol monomethyl ether acetate, methanol, CPI-210S (manufactured by San Apro Ltd.), Y-7006 (manufactured by Toray Dow Corning Co., Ltd.) The solid concentration was 60%.

  In the present example, an example was implemented in which the diameters (the outer diameter of the application range) of the coating liquid disposed in a spiral shape were different. Specifically, three examples in which the diameter of the coating liquid arranged in a spiral shape was 68 mm, 70 mm, and 71 mm were performed.

  Next, as a heating step, the setting temperature of the IR heater is set to 200 ° C. so that the atmosphere temperature becomes higher than 170 ° C., and the lens substrate is rotated by 50 rpm while the lens is mounted by the IR heater. The coating solution on the substrate was heated for 5 minutes.

  Next, as a cooling step, the lens substrate placed vertically was rotated at 50 rpm for 180 seconds (3 minutes) in a normal temperature atmosphere to air-cool the coating liquid on the lens substrate to room temperature.

  Furthermore, as a high-speed rotation step, the lens substrate in the vertical state is rotated at 1000 rpm for 10 seconds (or 1500 rpm for 5 seconds) to make the coating liquid on the lens substrate more uniform in thickness.

  Next, as a UV curing step, ultraviolet light (UV) was irradiated for 5 seconds while rotating the lens base placed in the vertical state at 50 rpm, and the ultraviolet curable resin in the coating liquid was cured to obtain a resin layer.

  Finally, as a heat treatment step, the lens substrate was heated in an oven at 110 ° C. for 1 hour to complete the resin layer forming method.

  Table 1 shows the thickness of the resin layer formed according to the above example and the W width of the liquid pool.

In each of Examples 1 to 5 in which the resin layer is formed according to the above-described embodiment, approximately 30 μm which is the desired thickness of the resin layer is obtained in the central portion of the lens base material. ) Is also below the tolerance of 2.5 mm.
In Examples 1 to 5, the outer diameter of the coating range of the coating solution and the speed and duration of rotation at high speed rotation are different.

  The reference example is an example in which the high speed rotation step is performed before the cooling step. Also in this example, a desired resin layer thickness of approximately 30 μm is obtained at the center of the lens substrate, and The width W (FIG. 4) of the resin pool 4a of the coating liquid 4 on the coated surface 1a of the lens substrate 1 is also less than the allowable range of 2.5 mm.

  Without being limited to the above-described embodiment of the present invention, various changes and modifications are possible within the scope of the technical idea described in the claims.

1: Lens base material
1a: coating surface 2: dispenser nozzle 4: coating solution 6: IR heater

Claims (10)

A resin layer forming method for forming a resin layer on at least one surface of a lens substrate for a plastic lens,
Applying a coating solution containing an ultraviolet curable resin to at least one surface of a lens substrate for a plastic lens;
Heating the coating solution on the lens substrate;
Irradiating the coating solution with ultraviolet light to cure the ultraviolet curable resin to obtain the resin layer;
A method of forming a resin layer characterized by The step of applying the coating solution is
Placing a coating solution on at least one side of the lens substrate;
Making the disposed coating solution substantially uniform in thickness on the lens substrate,
The method for forming a resin layer according to claim 1. The step of disposing the coating solution includes the step of helically arranging the coating solution on at least one surface of the lens substrate while rotating the lens substrate.
The method for forming a resin layer according to claim 2. The method further comprises a cooling step of cooling the coating liquid on the lens substrate to room temperature after the heating step.
The resin layer formation method of any one of Claims 1 thru | or 3. Rotating the lens substrate at high speed after the heating step;
The method for forming a resin layer according to any one of claims 1 to 4. The high speed rotation step is performed prior to the cooling step.
The method for forming a resin layer according to claim 5. The high speed rotation step is performed after the cooling step.
The method for forming a resin layer according to claim 5. The resin layer has a thickness of 20 to 40 μm,
The resin layer formation method of any one of Claims 1 thru | or 7. The width of the liquid pool formed at the outer edge of the resin layer is 10 mm or less
A resin layer forming method according to any one of claims 1 to 8. The heating in the heating step is performed by an infrared heater,
The resin layer forming method according to any one of claims 1 to 9.

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