JP2012006189A - Mold for molding plastic lens and method for producing plastic lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a means for reducing the amount of waste when a frame is fitted in a spectacle lens production process (in addition, the consumption of a plastic lens raw material liquid in cast polymerization).SOLUTION: A plastic lens molding mold has a bottomed mold 1 having a recess whose profile is circular and which is opened to one side while the other side is blocked, a circular mold 11 which lid-closes the open end of the bottomed mold 1, and a sealing member 13 which fixes the lid-closed state by surrounding the peripheries of the two molds. By keeping the recess of the bottomed mold lid-closed by the circular mold 11, a cavity for injecting a plastic lens raw material liquid is formed in the bottomed mold 1. In a method for producing the plastic lens, the plastic lens raw material liquid is injected in the cavity for injecting the plastic lens raw material liquid of the plastic lens molding mold, and the curing reaction of a plastic raw material liquid is carried out in the cavity to obtain the plastic lens.

Description

  The present invention relates to a molding die for molding a plastic lens and a method for producing a plastic lens using the same, and more specifically, the amount of waste at the time of placing a frame in a spectacle lens manufacturing process (further, a plastic lens raw material in cast polymerization) The present invention relates to a plastic lens molding die capable of greatly reducing the amount of liquid used) and a method for producing a plastic lens using the same.

  Examples of a method for obtaining a plastic lens by molding plastic into a lens shape include a casting polymerization method in which a plastic lens raw material liquid is polymerized in a mold. In the casting polymerization method, the lens optical surface is formed by transferring the molding surface shape.

  As the casting polymerization method, two circular molds (upper mold and lower mold) are inserted into an annular gasket, and a plastic lens raw material solution is injected into a cavity (space) formed by the gasket and the upper and lower molds for polymerization. (Refer patent document 1) The method (refer patent document 2) which superpose | polymerizes by inject | pouring a plastic lens raw material liquid into the cavity formed by winding a tape around the surrounding surface of two circular molds is known.

JP 2008-30431 A JP 2007-216665 A

As described above, the shape of the plastic lens polymerized in the cavity formed by surrounding the two circular molds is circular. In the present specification and the present invention, unless otherwise specified, the shape is a plan view shape.
However, most of the lenses framed in the spectacle frame when actually manufacturing spectacles have a short meridian direction and a long horizontal direction. Therefore, the actual situation is that the upper and lower ends of the circular plastic lens (lens blanks) obtained by the casting polymerization are cut and discarded. Since the plastic lens raw material liquid used in this discarded part is unnecessary for an actual spectacle lens, in order to reduce the amount of the raw material liquid used and to reduce the manufacturing cost, the part removed at the time of frame insertion Should be as small as possible. From the viewpoint of environmental load, it is desirable to reduce the amount of waste at the time of framing.

  Accordingly, an object of the present invention is to provide a means for reducing the amount of waste (further, the amount of plastic lens raw material used in casting polymerization) during frame making in the eyeglass lens manufacturing process.

As a means for reducing the amount of waste and the amount of plastic lens raw material used, it is conceivable that the shape of the lens formed by cast polymerization is non-circular. Therefore, it is conceivable to use a non-circular mold to mold the non-circular lens, but it is difficult to accurately align the two non-circular molds.
On the other hand, as a result of intensive studies to achieve the above object, the inventors of the present invention have one of the two molds having a circular outer shape and having a concave portion opened in one and closed in the other. A non-circular lens can be formed by using a bottom mold, and a molding die that can be easily positioned between the molds can be configured.Further, the bottomed mold can be applied to the manufacture of a circular lens. I found. This is because the shape of the bottomed mold is circular regardless of the shape of the lens to be molded, so that it is easy to align with the other circular mold, and the recess is designed to have a shape corresponding to the desired lens shape. This makes it possible to mold various shapes of lenses including non-circular lenses.
The present invention has been completed based on the above findings.

That is, the above object was achieved by the following means.
[1] A bottomed mold having a circular shape and having a recess that is open on one side and closed on the other;
A circular mold for closing the open end of the bottomed mold;
A sealing member for fixing the lid closed state by surrounding the two molds;
Have
A mold for molding a plastic lens, wherein a cavity for injecting a plastic lens material liquid is formed in the bottomed mold by closing the concave portion of the bottomed mold with a circular mold.
[2] The molding die for plastic lens molding according to [1], wherein a cross-sectional shape of the concave portion of the bottomed mold is non-circular.
[3] The plastic lens molding die according to [1] or [2], wherein the concave portion of the bottomed mold has a molding surface capable of forming an optical surface on the inner bottom surface.
[4] The gasket has a plastic lens raw material liquid inlet on a side surface, the bottomed mold has a notch at a peripheral edge of the side surface, and the injection port communicates with the notch so that the plastic is introduced into the cavity. The mold for molding a plastic lens according to any one of [1] to [3], wherein a flow path for injecting the lens raw material liquid is formed.
[5] The plastic lens raw material liquid is injected into the plastic lens raw material liquid injection cavity of the plastic lens molding die according to any one of [1] to [4], and the plastic raw material liquid is cured in the cavity. A plastic lens manufacturing method, characterized in that a plastic lens is obtained by performing.

According to the present invention, a plastic lens having a desired shape (circular or non-circular) can be produced by cast polymerization.
Furthermore, according to the present invention, it is possible to manufacture a non-circular plastic lens having a shape close to the shape of a lens to be framed as compared with a circular lens. Thereby, the amount of waste at the time of putting a frame and the usage-amount of a plastic lens raw material liquid can be reduced significantly.

It is the schematic which shows an example of the bottomed mold which comprises the shaping | molding die of this invention. It is sectional drawing of the bottomed mold shown in FIG. It is sectional drawing of the shaping | molding die used by normal casting polymerization. It is the schematic which shows an example of the shaping | molding die of this invention.

The plastic lens molding die of the present invention has a bottomed mold having a circular outer shape and having a recess that is open on one side and closed on the other, a circular mold that closes the opening end of the bottomed mold, and the above A sealing member for fixing the lid closed state by surrounding the periphery of the two molds. Here, when the concave portion of the bottomed mold is closed with a circular mold, a plastic lens raw material liquid injection cavity is formed in the bottomed mold.
In conventional casting polymerization, plastic lenses are polymerized in a cavity formed by surrounding two circular molds, so that the lenses that are necessarily formed are limited to circular lenses. On the other hand, in the plastic lens molding die of the present invention (hereinafter also simply referred to as “molding die”), the plastic lens raw material liquid injection cavity is formed by closing the concave portion of the bottomed mold with a circular mold. Therefore, the shape of the lens to be molded is determined by the shape of the recess. Therefore, lenses having various shapes including a non-circular lens can be molded by designing the shape of the concave portion to a shape corresponding to a desired lens shape. When manufacturing a circular lens, by changing the size (diameter) of the concave portion of the bottomed mold, it is possible to manufacture circular lenses of different sizes while using the same circular mold as the other mold. . Furthermore, even if the shape of the concave portion is non-circular, the bottomed mold is easy to align with the other circular mold because the outer shape is circular.
Hereinafter, the molding die of the present invention will be described in more detail.

  FIG. 1 is a schematic view (an upper view of FIG. 1 is a plan view, and a lower view of FIG. 1 is a perspective view) showing an example of a bottomed mold constituting the mold of the present invention. FIG. 1 shows a bottomed mold 1 having a concave portion 2 having a rounded quadrangular cross section, but the cross sectional shape of the concave portion is not limited to a rounded quadrangular shape, and is circular, elliptical, or polygonal. It is possible to take various shapes other than a circle such as. Since the shape of a general spectacle frame is short in the meridian direction and long in the horizontal direction, it is preferable to use a bottomed mold having a concave portion that approximates this shape from the viewpoint of further reducing the amount of waste. From the above, the cross-sectional shape of the recess of the bottomed mold is preferably a rounded square or an oval, and more preferably a rounded square. When a circular lens is molded, the cross-sectional shape (diameter) of the bottomed mold recess may be determined according to the desired lens shape.

  The cross-section of the concave portion corresponds to the shape of a widely used spectacle frame, for example, the length of the minor axis (meridian direction) is about 45 to 65 mm and the length of the major axis (horizontal direction) is about 60 to 75 mm. This is preferred because possible non-circular lenses are obtained.

The thickness of the lens to be molded is defined by the height of the inner side surface of the recess. Therefore, the height of the recess may be determined according to the desired lens thickness. The shape of the cylindrical portion 4 surrounding the recess may be determined according to the shape of the other mold and the sealing member so that it can be surrounded by the sealing member together with the other circular mold. For example, when an annular gasket is used as the sealing member, the outer diameter of the cylindrical portion may be determined so as to substantially match the inner diameter of the opening portion of the gasket into which the cylindrical member is inserted.
Moreover, the bottomed mold 1 shown in FIG. 1 has the notch 3 in the side surface peripheral part. This notch forms a part of the flow path of the plastic lens raw material liquid. This point will be described later.

  FIG. 2 is a cross-sectional view of the bottomed mold shown in FIG. 2 is a cross-sectional view taken along line YY in FIG. 1 and FIG. 2 is a cross-sectional view taken along line XX in FIG. The opening end surface 5 of the bottomed mold shown in FIG. 2 is a contact surface with the circular mold. The opening end surface may have a curved surface or an inclined shape according to the surface shape of the abutting circular mold. Thereby, the lid closed state with the circular mold can be stabilized. Moreover, in order to improve the stability of the lid closed state with the circular mold, a flange portion can be formed on the opening end surface of the bottomed mold.

  The bottomed mold may be made of metal or resin. From the viewpoint of easy removal of the molded lens, the bottomed mold is preferably made of resin. The resin-made bottomed mold can be usually obtained by molding a thermoplastic resin used for manufacturing a gasket by a known molding method such as injection molding. Here, a bottomed mold having a molding surface on which an optical surface can be formed by molding a bottomed mold using a mold whose surface is transferred to the inner bottom surface 2 'of the bottomed mold. Can be obtained. By using such a bottomed mold, the surface onto which the inner bottom surface of the bottomed mold is transferred can be used as the optical surface of the lens as it is without polishing or the like.

  The thermoplastic resin is preferably an olefin resin and particularly preferably a polyethylene elastomer from the viewpoints of moldability, flexibility, heat resistance, monomer stability, price, and the like. Specific examples of the olefin elastomer include a polyethylene elastomer made of low density polyethylene, a polypropylene elastomer in which a rubber component is finely dispersed in a polypropylene homopolymer, an ethylene-vinyl acetate copolymer, and an ethylene-alkyl acrylate copolymer. Can be mentioned. The notch can be formed by cutting the peripheral edge of the bottomed mold side surface with a cutter or the like. As will be described later, an opening may be provided on the side surface instead of the notch, and the opening can be formed by making a hole in the side surface by a known opening means of a cutter or a punch.

The mold of the present invention can be constructed by replacing the upper mold or the lower mold of the mold used in normal casting polymerization with the above-mentioned bottomed mold. Thus, the ability to configure the mold without greatly changing the configuration of the mold conventionally used is advantageous in that it does not require a significant change in the manufacturing process.
Here, based on FIG. 3, the shaping | molding die used by normal casting polymerization is demonstrated. 3 is a concave mold having a molding surface on the concave surface side to form the front surface (convex surface) of the lens, and a convex surface to form the rear surface (concave surface) of the lens. A cavity mold 14 is formed by having a circular mold (second mold) 12 having a molding surface on the side, and an annular gasket 13 surrounding the peripheral surfaces of both molds. The first mold and the second mold have a non-transfer surface (non-use surface 17) that can be handled by a manufacturing jig and a transfer surface (use surface 16) for transferring the optical surface of the lens. The use surface 16 is a surface for transferring the optical surface shape and surface state of the lens. In this mold, the plastic lens raw material liquid injected from the injection port 15 is introduced into the cavity 14 from the injection port 18 provided on the side surface of the gasket 13, and a curing reaction is performed in the cavity 14. Therefore, the obtained molded body is circular like the mold.

  In contrast, the mold of the present invention can be configured by replacing the first mold or the second mold with a bottomed mold. As an example, FIG. 4 shows a cross-sectional view of a mold configured by replacing the second mold of the mold shown in FIG. 3 with the bottomed mold shown in FIG. 4 is a cross-sectional view taken along line YY in FIG. 1 and FIG. 4 is a cross-sectional view taken along line XX in FIG. In the mold shown in FIG. 4, the concave portion 2 closed by the first mold 11 closing the open end of the bottomed mold 1 is a plastic lens raw material liquid injection cavity. Therefore, a molded product obtained by performing a curing reaction in this has a shape similar to that of the concave portion. Therefore, for example, a non-circular lens can be obtained by making the cross-sectional shape of the concave portion non-circular. In the present invention, “lid closing” means closing the space by covering the open space.

  As shown in the lower diagram of FIG. 4, the plastic lens raw material liquid is introduced into the plastic lens raw material liquid injection cavity 2 by communicating the inlet 18 provided on the side surface of the gasket and the notch 3 provided in the peripheral edge of the side surface of the bottomed mold. Is formed. It is possible to form a flow path by forming an opening on the side surface of the bottomed mold instead of the notch and communicating the opening and the injection port 18, but from the viewpoint of easy alignment. It is preferable to form a flow path by providing a notch in the bottomed mold. In addition, forming the flow path by communicating the notched or opening of the bottomed mold with the inlet of the gasket as described above is advantageous for facilitating the positioning of the gasket and the bottomed mold. In addition, the holding part 19 can be provided in a gasket inner peripheral surface as shown in FIG. This holding part 19 is for abutting the peripheral part of the bottomed mold and positioning and holding the bottomed mold. For example, the holding part 19 is provided on the inner peripheral surface of the gasket as a band or as a protrusion arranged at a constant interval. Can do.

  In the embodiment described above, an annular gasket is used as a sealing member for fixing the closed state of the mold by surrounding two molds. In the present invention, an adhesive tape is used instead of the gasket as a sealing member. It can also be used.

[Plastic lens manufacturing method]
The method for producing a plastic lens according to the present invention includes injecting a plastic lens raw material liquid into a plastic lens raw material liquid injection cavity of the molding die for molding a plastic lens according to the present invention, and performing a curing reaction of the plastic raw material liquid in the cavity. A plastic lens is obtained.
In the method for producing a plastic lens of the present invention, a plastic having the same shape as the concave portion is obtained by performing a curing reaction of the plastic lens raw material liquid in a cavity formed by closing the concave portion of the bottomed mold with a circular mold. A lens can be manufactured. Therefore, for example, if the cross-sectional shape of the recess is non-circular, a non-circular lens can be obtained. As described above, the non-circular plastic lens is advantageous both in terms of environment and cost because it can reduce the amount of waste at the time of frame insertion and the amount of plastic lens raw material used compared to the conventional circular lens. It is.
Hereafter, the manufacturing method of the plastic lens of this invention is demonstrated in detail.

  The details of the mold used in the plastic lens manufacturing method of the present invention are as described above.

  The plastic lens raw material liquid (hereinafter also referred to as “lens raw material liquid”) used in the method for producing a plastic lens of the present invention contains a curable component, and various types of plastic lens base materials that are usually used for spectacle lenses. Polymeric raw material monomers, oligomers and / or prepolymers can be included, and a mixture of two or more monomers can also be included to form a copolymer. The curable component may be a thermosetting component or a photocurable component, but in the casting polymerization, a thermosetting component is usually used. If necessary, a catalyst selected according to the kind of monomer can be added to the lens raw material liquid. The lens raw material liquid may also contain various commonly used additives.

  Specific examples of the lens raw material liquid include, for example, a copolymer of methyl methacrylate and one or more other monomers, diethylene glycol bisallyl carbonate resin (CR-39), diethylene glycol bisallyl carbonate, and one or more other monomers. Copolymer, polyurethane and polyurea copolymer, polycarbonate, polystyrene, polyvinyl chloride, unsaturated polyester, polyethylene terephthalate, polyurethane, polythiourethane, sulfide resin using ene-thiol reaction, vinyl polymer containing sulfur The raw material liquid which can polymerize etc. is mentioned. Injection of the raw material liquid into the plastic lens raw material liquid injection cavity can be performed through the above-described flow path.

  Next, the lens raw material liquid injected into the cavity is heated, irradiated with light, and the like, whereby a curable component contained in the lens raw material solution undergoes a curing reaction to obtain a lens-shaped molded body. Curing reaction conditions (for example, heating temperature raising program) are not particularly limited, and may be determined according to the type of lens raw material liquid to be used. After completion of the curing process, the plastic lens can be taken out by separating (releasing) the two molds that are in close contact with the lens. As described above, by using a bottomed mold having an inner bottom surface to which a mirror surface of a mold is transferred, a plastic lens having an optical surface to which the inner bottom surface of the bottomed mold is transferred can be obtained.

  The plastic lens thus obtained may be a finish lens (lens blank optically finished on both sides) or a semi-finished lens (lens blank optically finished on only one surface). . The semi-finished lens has an optically finished surface, and the back surface is polished so as to have a desired lens power according to the lens prescription value.

  Thereafter, the plastic lens whose both surfaces are optically finished is trimmed into a frame shape of the spectacle frame at the spectacle store or by a manufacturer who has received an order from the spectacle store, and then beveled. A functional film for imparting desired performances such as an antireflection film and a water repellent film before and after that can be formed on the lens by a known method, if necessary. Glasses are completed by fitting a lens, which is rimmed and has a functional film as necessary, into a spectacle frame. The shape of the plastic lens produced in the present invention may be circular or non-circular, and is not particularly limited. As described above, since the non-circular lens is closer to the shape of the lens to be framed than the circular lens, the amount of the part that is removed and discarded as an unnecessary part in the edging process can be greatly reduced. This is advantageous.

  EXAMPLES The present invention will be further described below with reference to examples, but the present invention is not limited to the embodiments shown in the examples.

[Example 1]
(1) Molding of bottomed mold Using polyethylene elastomer (Excellen FX, manufactured by Sumitomo Chemical Co., Ltd.), which is an olefin-based thermoplastic resin, a concave portion (short diameter 62 mm, long diameter 73 mm, high inner side surface) A bottomed mold (outer diameter 81.5 mm, height 23 mm) having a circular outer shape having a thickness of 18 mm) was obtained by injection molding. As the mold for forming the bottomed mold, a mold in which the surface transferred to the inner bottom surface of the bottomed mold concave portion is a concave surface subjected to mirror polishing. By using this mold, a bottomed mold was formed in which the inner bottom surface of the recess was a convex molding surface capable of forming an optical surface.
A notch was formed by a cutter at the peripheral edge of the side surface of the molded bottomed mold.
Through the above steps, a bottomed mold having the shape shown in FIG. 1 was obtained.

(2) Assembly of mold The bottomed mold obtained in (1) above was inserted into an annular gasket made of the same polyethylene elastomer as described above. At this time, the gasket was positioned so that the inlet on the side of the gasket and the notch of the bottomed mold coincided. Thereafter, a circular glass mold having a concave molding surface was fitted into the opening of the gasket to form a convex surface, thereby assembling a molding die having a sectional view shown in FIG.

(3) Molding of plastic lens After the molding die obtained in the above (2) is arranged so that the inlet part of the gasket faces vertically upward, the raw material of diethylene glycol bisallyl carbonate resin (CR-39) from the inlet part The solution was introduced into a plastic lens raw material liquid injection cavity formed by closing the concave portion of the bottomed mold with a circular mold, and after the cavity was filled, a curing reaction was performed according to a predetermined polymerization program. After completion of the curing reaction, the lens was removed from the mold. The shape of the lens taken out from the mold was the same shape as the concave portion of the bottomed mold, that is, a rounded quadrangle with a minor axis 62 mm and a major axis 73 mm. That is, a non-circular lens could be obtained. The thickness of the obtained lens was the same as the height of the inner side surface of the recess.

[Example 2]
A circular lens having a diameter of 75 mm was obtained by producing a mold and molding a plastic lens in the same manner as in Example 1 except that the cross-sectional shape of the concave portion of the bottomed mold was changed to a circle (diameter 75 mm).

  As shown in the above embodiment, according to the present invention, not only a circular lens but also a non-circular lens can be obtained. In both the first and second embodiments, unnecessary parts are removed from the obtained lenses according to the frame shape of the spectacle frame, and the spectacles can be completed by placing them in the spectacle frame. The non-circular lens obtained in Example 1 is approximately 35% less in volume than the circular lens obtained in Example 2. Therefore, the amount of plastic lens raw material used to obtain a single lens can be reduced by the small volume, and the amount removed and discarded in the edging process for frame insertion is reduced accordingly. can do.

  The present invention is useful in the field of manufacturing eyeglass lenses.

  DESCRIPTION OF SYMBOLS 1 ... Bottomed mold, 2 ... Recessed part, 3 ... Notch, 4 ... Cylindrical part, 5 ... Open end surface, 11 ... Circular mold, 13 ... Gasket

Claims (5)

A bottomed mold having a circular shape and having a recess that is open on one side and closed on the other;
A circular mold for closing the open end of the bottomed mold;
A sealing member for fixing the lid closed state by surrounding the two molds;
Have
A mold for molding a plastic lens, wherein a cavity for injecting a plastic lens material liquid is formed in the bottomed mold by closing the concave portion of the bottomed mold with a circular mold. The mold for molding a plastic lens according to claim 1, wherein a cross-sectional shape of the concave portion of the bottomed mold is non-circular. 3. The plastic lens molding die according to claim 1, wherein the concave portion of the bottomed mold has a molding surface capable of forming an optical surface on an inner bottom surface. The gasket has a plastic lens raw material injection port on a side surface, the bottomed mold has a cutout at a peripheral edge of the side surface, and the injection port and the cutout communicate with each other, thereby allowing the plastic lens raw material solution to enter the cavity. The mold for molding a plastic lens according to any one of claims 1 to 3, wherein a flow path for injecting the liquid is formed. The plastic lens raw material liquid is injected into the plastic lens raw material liquid injection cavity of the plastic lens molding die according to any one of claims 1 to 4, and the plastic raw material liquid is cured in the cavity. A method for producing a plastic lens, comprising obtaining a plastic lens.