JPH04182109A - Manufacture of plastic lens - Google Patents

Abstract

PURPOSE:To manufacture a plastic lens having high surface hardness without the use of large facilities and devices by forming an organic resin layer containing glass powder over a lens transfer surface of a mold for injection molding to carry out a surface coating treatment simultaneously with formation of the plastic lens. CONSTITUTION:In order to form an organic resin layer containing glass powder over a lens transfer surface of a mold for use in injection molding of a plastic lens, it is preferable to apply a solution of organic resin containing glass powder or to attach a film coated with a solution of organic resin containing glass powder to a lens transfer surface of a mold. As the glass powder, powder of silicate glass, borate glass, fluorine glass, photochromic glass can be used and particle diameter is desired to be 20mum or smaller. After formation of an organic resin layer containing glass powder by the above-mentioned method, a plastic lens is produced by known injection molding to obtain a plastic lens 9 having surface hardened films 11a, 11b. When a film is used, it is removed after molding.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing a plastic lens with excellent surface hardness.

[Prior Art] Injection molding methods for plastic lenses made of thermoplastic resins such as polycarbonate are known. For example, Japanese Patent Publication No. 12019/1983 discloses injection molding methods for plastic lenses made of thermoplastic resin such as polycarbonate. - forming a cavity with a volume larger than the finished lens using a pair of optical inserts, injecting into the cavity an amount of polycarbonate close to the mass of the finished lens, and then closing the mold to compress the polycarbonate; A method is disclosed in which the molten polycarbonate in the cavity is then cooled and solidified to form a plastic lens.

[Problems to be Solved by the Invention] However, plastic lenses have a significantly inferior surface hardness compared to glass lenses. For example, when used as eyeglass lenses, a surface hardness that can withstand daily use is required. Inevitably, lens surface treatment is necessary to impart surface hardness, and the above-mentioned
In the plastic lens obtained by the method of Publication No. 019, a surface treatment step after lens molding is essential.

In addition, this surface treatment process requires a process of applying the surface treatment material by dipping or spin coating, and a curing process of the surface treatment material by heat treatment, UV treatment, etc. after the coating process, and these processes are performed in a clean environment. It must be carried out in a work environment that maintains a
It requires a large amount of equipment and equipment, and the complexity and cost of the process were considered major issues.

The present invention has been made in order to solve the above-mentioned problems, and its purpose is to provide a method for manufacturing a plastic lens having excellent surface hardness without using a large amount of equipment or equipment. There is a particular thing.

[Means for Solving the Problems] The present invention has been made to achieve the above-mentioned object, and the present invention is directed to the injection molding of a glass powder-containing resin layer when manufacturing a plastic lens by injection molding. The gist of this invention is a method for manufacturing a plastic lens, which is characterized in that a plastic lens is formed on the lens transfer surface of a mold for use, and a plastic lens surface coating treatment is performed simultaneously with the molding of the plastic lens to obtain a plastic lens having a surface hardening film. be.

The present invention will be explained in detail below.

The raw material resin used in the method for manufacturing a plastic lens by injection molding of the present invention includes thermoplastic resins such as acrylic resin, polycarbonate resin, and polystyrene resin.

The method of manufacturing plastic lenses by injection molding is known per se, and in addition to the method described in the above-mentioned Japanese Patent Publication No. 12019/1982, there is also the method described in Japanese Patent Application Publication No. 1999/1999 filed by the applicant.
No. 275111, Japanese Unexamined Patent Publication No. 1-291915, Japanese Unexamined Utility Model No. 1
The methods and apparatuses described in Japanese Utility Model Application No. 1-169312 and Japanese Utility Model Application Publication No. 1-148315 can be applied as they are to the method of manufacturing a plastic lens of the present invention. Here, the method of manufacturing a plastic lens by injection molding will be briefly described as follows.

First, after precisely weighing the raw material resin of the plastic lens, it is heated to a high temperature (for example, in the case of acrylic resin, about 230 to 24
0° C.) to melt it and fill it into a cavity formed between a pair of optical inserts in an injection molding device.

Next, the temperature inside the cavity is lowered to a temperature at which the resin still remains in a fluid state (nearly 130°C in the case of acrylic resin), and then the temperature is maintained at a high pressure (for example, around 130°C).
000Kg/cm3) to solidify the resin.

Next, the resin is cooled while controlling the mold temperature and pressure so as to maintain the solidified state of the resin and the dynamic elastic modulus curve of the resin. Take it out.

The method for manufacturing a plastic lens of the present invention includes forming a resin layer containing glass powder on the lens transfer surface of a plastic lens injection mold when manufacturing a plastic lens by the injection molding described above, and simultaneously molding the plastic lens. This method is characterized in that a plastic lens surface coating treatment is performed to obtain a plastic lens having a surface hardening film.

In the present invention, the formation of the glass powder-containing resin layer on the lens transfer surface of the plastic lens injection mold is preferably carried out by the following method.

(a) Method of applying a resin solution containing glass powder to the lens transfer surface of a mold for plastic lens injection molding (b) Attaching a film coated with a resin solution containing glass powder to the lens transfer surface of a mold for plastic lens injection molding In methods (a) and (b) above, examples of the glass powder include those made of silicate glass, borate glass, fluorine glass, and photochromic glass, such as commercially available glass powder manufactured by HOYA Co., Ltd. UV5NEO1LHI
, LHI-II, and THI-If may be used alone or in combination of two or more. The particle size of the glass powder is 20 μm or less, especially 5 μm or less.
It is preferable that it is 20 micrometers. The reason is that the particle size is 2
This is because if the thickness exceeds 0 μm, the resulting surface-cured film may lose its smoothness or become susceptible to birefringence.

As the resin for containing the glass powder, thermoplastic resins and thermosetting resins such as acrylic resins, polyester resins, epoxy resins, alkyd resins, urethane resins, and acrylic-modified polyester resins can be used. These resins are added to an organic solvent together with the glass powder and, if necessary, a level link, an agent, and a curing agent to obtain a glass powder-containing resin solution. The mixing ratio of glass powder and resin is 40 to 90 parts by weight of the former to 6 parts by weight of the latter.
It is preferable to use 0 to 50 parts by weight. The reason is that if the amount of glass powder is less than 40 parts by weight and the resin exceeds 60 parts by weight, the surface hardness will be insufficient; So,
This is because it becomes difficult to uniformly coat the mold surface or film surface.

As organic solvents, aromatic hydrocarbons such as benzene, toluene, and xylene, esters such as ethyl acetate and butyl acetate, ketones such as methyl ethyl ketone, and chlorinated hydrocarbons such as methylene chloride can be used. be.

In method (a), applying the glass powder-containing resin solution to the lens transfer surface of the plastic lens mold,
This is carried out using a method such as a spray method, and a resin layer containing glass powder is formed on the lens transfer surface of the mold.

On the other hand, in method (b), a glass powder-containing resin solution is applied to one side of a film such as a polyester film such as polyethylene terephthalate using a spray method or the like.

The thickness of this film is preferably 10 to 50 μm.

The reason for this is that if the thickness is less than 10 μm, the film is likely to tear or wrinkle, while if it exceeds 50 μm, the film will not follow the lens transfer surface of the mold. Next, after heating the film coated with the glass powder-containing resin solution, the film is attached so that the non-coated surface of the film comes into contact with the lens transfer surface of the mold, so that the glass powder-containing resin is applied to the lens transfer surface of the mold. form a layer. The attachment of this film to the lens transfer surface of the mold is preferably carried out using means such as vacuum suction in order to prevent the occurrence of wrinkles and the like.

The refractive index of the glass powder-containing resin layer formed on the lens transfer surface of the mold by the above methods (a) and (b) is preferably the same as or similar to the refractive index of the plastic lens obtained by injection molding. preferable. The reason for this is that if the difference in refractive index between the two is large, light reflection will increase at the interface and transparency will be impaired.

The thickness of the glass powder-containing resin layer formed on the lens transfer surface of the mold is determined as appropriate depending on the desired thickness of the surface-cured film in the finally obtained plastic lens with a surface-cured film. For example, it is preferable to set it as the range of 1-5 micrometers.

After forming a glass powder-containing resin layer on the lens transfer surface of an injection molding mold by the above method (a) or (b), when a plastic lens is manufactured by injection molding as described above, at the same time a plastic lens is formed. A lens surface coating treatment is also carried out at the same time to obtain a plastic lens having a surface hardened film. In the case of method (b),
After obtaining a plastic lens having a surface-cured film made of a glass powder-containing resin layer, it is necessary to peel off the film such as a polyester film supporting the glass powder-containing resin layer.

As described above, according to the present invention, since the plastic lens surface coating treatment is performed at the same time as the plastic lens molding, there is an advantage that a plastic lens having a surface hardening film can be obtained without performing a surface coating treatment after the plastic lens molding. There is.

Further, the plastic lens with a surface hardening film obtained above can be further subjected to antireflection treatment, antifogging treatment, dyeing treatment, etc. to impart additional functions. For example, to form an antireflection film, a normal film forming method of alternately forming high refractive index layers and low refractive index layers is used. In addition, a sintered body of SiO2 was used as a vapor deposition raw material for the base layer and a low refractive index film, and ZrO2 powder, Ta205 powder, and Y2O3 powder were used in a molar ratio of 1:1 as a vapor deposition raw material for a mixed vapor deposition film that was a high refractive index film. 1
．． After mixing at a ratio of 3:0.2 and press forming, 120
Using a pellet formed by sintering at 0°C, the above-mentioned plastic lens with a surface hardening film was placed in a vapor deposition tank, heated to 85°C while exhausting air, and heated to 2X 10-'Torr.
After evacuating the air to a maximum temperature, the above-mentioned evaporation raw materials were vapor-deposited using an electron beam heating method to form a base layer consisting of a silicon oxide film, a composite of a mixture vapor-deposited film and a silicon oxide film, etc., as shown in Table 1. A first layer of a low refractive index film consisting of a film, a second layer of a high refractive index film consisting of a mixed vapor deposition film, and a third layer of a silicon oxide film.
It is also possible to obtain a multilayer antireflection film having a film structure formed by sequentially forming layers of low refractive index films.

Note that the base layer is preferable as it improves the adhesion with the coating lens.

Table-1 be.

[Examples] Hereinafter, the present invention will be further explained with reference to Examples, but the present invention is not limited to these Examples.

Example 1 (I) Preparation of glass powder-containing resin solution (A) Refractive index 1.
No. 49 silicate glass (5G-2 manufactured by HOYA Corporation) was powdered with a particle size of 1 to 10 μm using a ball mill, and 5 parts by weight of this glass powder was mixed with 5 parts by weight of polymethyl methacrylate and 400 parts by weight of toluene. A glass powder-containing resin solution (A) was obtained by dispersing it in the dissolved solution.

(II) Application of glass powder-containing resin solution (A) to the lens transfer surface of the optical insert - Figure 1 shows a glass powder-containing resin solution (A) applied to the lens transfer surface of a pair of optical inserts of a plastic lens injection molding device. It is a figure showing the state where is being applied. In the plastic lens injection molding apparatus shown in the figure, 1a and 1b are an upper mold and a lower mold, respectively, 2a and 2b are optical inserts for the upper mold and an optical insert for the lower mold, respectively, and 3a and 3b are respectively They are a mold mother mold for the upper mold and a mold mother mold for the lower mold, 4a and 4b are an optical insert fitting part for the upper mold and an optical insert fitting part for the lower mold, respectively, and 5a and 5b are respectively for the upper mold. 6a and 6b are a cylinder rod part for the upper mold and a cylinder rod part for the lower mold, respectively.

A spray device 8a is applied to the lens transfer surfaces of the optical inserts 2a and 2b of this plastic lens injection molding machine.
, 8b, the glass powder-containing resin solution (A) was applied to form coating films 7a and 7b of the solution (A) with a film thickness of 2 μm. The mold temperature during coating was approximately 80°C.

(III) Injection molding of plastic lenses Polymethyl methacrylate (
Acrypet VH) manufactured by Mitsubishi Rayon Co., Ltd. was used. After precisely measuring this raw resin, it is heated to approximately 230 to 240°C, and then filled in a molten state into the cavity formed between a pair of optical inserts, and then the temperature inside the cavity is lowered to approximately 130°C. The resin was then solidified by applying pressure to about 1000 Kg/cm3 at this temperature. Next, while controlling the mold temperature and pressure to keep the dynamic elastic modulus curve of the resin constant,
After cooling the resin, the resulting plastic lens was removed from the mold.

A cross-sectional view of the plastic lens obtained in this example is shown in the second figure.
As shown in the figure. As is clear from FIG. 2, this plastic lens 9 has a film thickness of 2 μm derived from the coating film of the glass powder-containing resin solution (A) on the concave and convex sides of the outer surface of the lens base material 10. Surface hardened films 11a and 11b were formed. The plastic lens 9 has a center thickness of 2 mm, a dioptric power of -3,00 diopters, and an aspherical optical design on the convex side.

(mV) Physical property evaluation of plastic lens with surface hardening film The results of physical property evaluation of the obtained plastic lens with surface hardening film are as follows.

(1) Scratch Resistance Test The lens surface was rubbed with #0000 still wool and a load of 10 kg, and the resistance to scratches was visually judged.

The judgment criteria were as follows.

A: Hardly any scratches occur even if rubbed strongly B...
・Strong (Significant scratches occur when rubbed C: Scratches similar to those of the lens substrate result. As a result, the plastic lens with the surface hardened film obtained in this example was rated A.

(2) Adhesion 100 cross-cuts were made at 1 mm intervals, cellophane tape was strongly applied and quickly peeled off, and the presence or absence of peeling of the cured film was examined. As a result, no peeling was observed.

(3) Appearance The transparency of the film and molded lens was visually inspected, and the presence or absence of coating unevenness and coloring was also investigated. As a result, the product of this example was transparent and beautiful.

(4) Impact resistance A 16 g steel ball was dropped from a height of 127 cm onto the center of a lens with a center thickness of 2 mm to check for damage.

As a result, no damage was observed.

Example 2 (I) Preparation of a film with a glass powder-containing resin layer The glass powder-containing resin solution (A) obtained in (1) of Example 1 was applied to one side of a 25 μm thick PET (polyethylene terephthalate) film. It was applied by a spray method to form a PET film with a glass powder-containing resin layer.

(II) Attaching the optical insert of the PET film with the resin layer containing glass powder to the lens transfer surface As shown in FIG.
After heating at b, a pair of optical inserts 2a1
I sent it between 2b. The fed PET films 12a and 12b with a resin layer containing glass powder are passed through a vacuum device 14.
When vacuum suction is performed by a and 14b, the PET film 12 with a glass powder-containing resin layer is removed as shown in FIG. 3(b).
゛The non-coated surfaces of a and 12b (the surfaces on which the glass powder-containing resin layer is not coated) are optical inserts 2a and 2b.
By closely contacting the lens transfer surfaces of the optical inserts 2a, 2b, the glass powder-containing resin layer-coated PET films 12a, 1'2b were attached to the lens transfer surfaces of the optical inserts 2a, 2b.

(m) Injection molding of a plastic lens After obtaining a plastic lens by injection molding in the same manner as in Example 1 (m), the PET film was peeled off to obtain a plastic lens having a hardened surface film as shown in Figure 2. Ta.

(IV) Evaluation of physical properties of plastic lens with hardened surface film The suitability of this plastic lens with hardened surface film as an eyeglass lens was determined using the same evaluation method as in Example 1. There was no difference in performance from plastic lenses with cured films, and all were good.

[Effects of the Invention] According to the present invention, a plastic lens having a surface hardening film can be obtained by performing surface coating treatment at the same time as injection molding of a plastic lens. In comparison, the operation can be simplified. In addition, the obtained plastic lens with a hardened surface film has excellent scratch resistance and
It has excellent adhesion, appearance, and impact resistance, and is suitable for use as an eyeglass lens, for example.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a state in which a resin solution containing glass powder is applied to the lens transfer surface of an optical insert of a plastic lens injection molding apparatus in Example 1. FIG. FIG. 3 is a cross-sectional view of a plastic lens having a hardened surface film, as shown in Example 2.
FIG. 3 is a diagram showing a state in which a glass powder-containing resin layer-coated film is attached to the lens transfer surface of the optical insert of the plastic lens injection molding apparatus. 1a, 1b...upper mold, lower mold, 2a, 2b...optical insert for upper mold, optical insert for lower mold, 3a, 3b... mold mother mold for upper mold, mold mother mold for lower mold ,
4a, 4b... Upper mold optical insert fitting part, lower mold optical insert fitting part, 5a, 5
b... Clamp part for upper mold, clamp part for lower mold, 6a,
6b... Cylinder rod part for upper die. Cylinder rod part for lower mold, 7a, 7b... Coating film of resin solution containing glass powder, 8a, 8b... Spray device, 9... Plastic lens having surface hardening film, 1
0...Lens base material, 11a, 11b...Surface cured film, 12a, 12b...P with glass powder-containing resin layer
ET film, 13a, 13b... heater,] 4a
. 14b...vacuum device

Claims (4)

[Claims] (1) When manufacturing plastic lenses by injection molding, a resin layer containing glass powder is formed on the lens transfer surface of a plastic lens injection mold, and at the same time as the plastic lens is molded, a plastic lens surface coating treatment is applied to the surface. A method for producing a plastic lens, the method comprising obtaining a plastic lens having a cured film. (2) In the method for manufacturing a plastic lens according to claim (1), the formation of the glass powder-containing resin layer on the lens transfer surface of the plastic lens injection molding mold involves injecting the glass powder-containing resin solution into the mold. or by attaching a film coated with a glass powder-containing resin solution to the lens transfer surface of the mold. (3) In the method for manufacturing a plastic lens according to claim (1) or (2), an antireflection film is provided on the surface hardened film of the plastic lens having the surface hardened film.
Method of manufacturing plastic lenses. (4) The method for manufacturing a plastic lens according to any one of claims (1) to (3), wherein the obtained plastic lens is a thermoplastic resin eyeglass lens.