JP2011245830A - Mold for molding plastic lens and method for manufacturing plastic lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a means for reducing an amount of waste during framing in a spectacle lens manufacturing process (and an amount of use of plastic lens raw material liquid during cast-polymerization).SOLUTION: A mold for molding a plastic lens includes: two circular molds 11, 12 facing each other with a predetermined interval; a cylindrical member 4 entered into the interval; and a sealing member 13 which fixes the entering state of the two molds and the cylindrical member by surrounding the peripheries of the molds and the cylindrical member. The cylindrical member internally has a through hole of a non-circular cross section. By sealing the through hole by the two holes, a cavity 2 for injecting plastic lens raw material liquid is formed.

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 present inventors have inserted a cylindrical member capable of forming a non-circular cavity between the molds, while using a circular mold, The present inventors have found that a non-circular lens can be manufactured and have completed the present invention.

That is, the above object was achieved by the following means.
[1] Two circular molds facing each other at a predetermined interval;
A cylindrical member sandwiched between the gaps;
A sealing member for fixing the sandwiched state between the mold and the cylindrical member by surrounding the peripheral surfaces of the two molds and the cylindrical member;
Have
The cylindrical member has a through-hole having a non-circular cross-sectional shape, and the through-hole is sealed with the two molds to form a plastic lens raw material liquid injection cavity. Mold for plastic lens molding.
[2] The plastic lens molding die according to [1], wherein a cross-sectional shape of the through hole is a rounded quadrangle.
[3] The plastic lens molding die according to [1] or [2], wherein the sealing member is an annular gasket.
[4] The gasket has a plastic lens raw material liquid inlet on the side surface, the cylindrical member has a notch in the peripheral edge of the side surface, and the injection port and the notch communicate with each other, so that the plastic lens The mold for molding a plastic lens according to any one of [1] to [3], wherein a flow path for injecting the 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 method for producing a plastic lens, characterized in that a non-circular plastic lens is obtained by performing.

  According to the present invention, it is possible to manufacture a plastic lens having a shape close to a lens shape 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.

In the shaping | molding die of this invention, it is the schematic which shows an example of the cylindrical member inserted | pinched between two circular molds. It is sectional drawing which shows an example of the mold and gasket which comprise a part of shaping | molding die of this invention. It is sectional drawing of the state which has arrange | positioned the cylindrical member shown in FIG. 1 in the cavity shown in FIG.

[Molding mold for plastic lens molding]
The plastic lens molding die of the present invention includes two circular molds facing each other at a predetermined interval, a cylindrical member sandwiched in the interval, and surrounding the peripheral surfaces of the two molds and the cylindrical member. And a sealing member for fixing a sandwiched state between the mold and the cylindrical member. Here, the cylindrical member has a through hole having a non-circular cross section. The through hole is sealed with the two molds, thereby forming a plastic lens raw material liquid injection cavity.
Since the plastic lens molding die of the present invention (hereinafter also simply referred to as “molding die”) has a cavity formed by sealing a non-circular through hole, the plastic lens raw material liquid is contained in the cavity. By performing the curing reaction, a non-circular plastic lens can be obtained. According to the non-circular plastic lens, it is possible to reduce the amount of waste at the time of frame insertion compared to the circular lens. Furthermore, the amount of the plastic lens raw material liquid used can be reduced compared to the case of manufacturing a circular lens. Further, since a circular mold can be used, a non-circular lens can be manufactured without changing the optical design from the conventional one.
Hereinafter, the molding die of the present invention will be described in more detail.

  FIG. 1 is a schematic view showing an example of a cylindrical member sandwiched between two circular molds in the molding die of the present invention (the left diagram in FIG. 1 is a plan view, and the right diagram in FIG. 1 is a perspective view). FIG. 1 shows a cylindrical member 1 having a through-hole 2 having a rounded quadrangular cross-section, but the cross-sectional shape of the through-hole is not limited to a rounded quadrangular shape, and may be an ellipse, a polygon, or the like. Various shapes other than circular can be taken. 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 cylindrical member having a through hole similar to this shape from the viewpoint of further reducing the amount of waste. Is preferably rounded square or oval, more preferably rounded square.

  For example, the through hole has a short diameter (in the meridian direction) of about 45 to 65 mm and a long diameter (in the horizontal direction) of about 60 to 75 mm, so that the shape of the widely used spectacle frame can be accommodated. This is preferable because a non-circular lens can be obtained.

The thickness of the lens to be molded is defined by the height of the through hole. Therefore, the height of the through hole may be determined according to the desired lens thickness. Moreover, what is necessary is just to determine the shape of the cylindrical part 4 surrounding the said through-hole according to the shape of the mold to be used, and a sealing member so that it can surround with a sealing member with two molds. 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 cylindrical member 1 shown in FIG. 1 has the notch 3 in a 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.

  The cylindrical member can be usually obtained by molding a thermoplastic resin used for manufacturing a gasket by a known molding method such as injection molding. 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 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 molding die of the present invention can use any molding die used in normal casting polymerization without any limitation, except that the cylindrical member is sandwiched between two molds. That is, the mold according to the present invention can be configured by disposing the cylindrical member in the cavity of the mold used in normal casting polymerization. Thus, the ability to use a conventionally used mold is advantageous because a non-circular lens can be manufactured without significant changes in the manufacturing process.
For example, as shown in FIG. 2, the mold used in normal casting polymerization is a concave mold having a molding surface on the concave surface side to form the front surface (convex surface) of the lens. A second mold 12 having a molding surface on the convex surface side is formed to form a rear surface (concave surface), and an annular gasket 13 surrounds the peripheral surfaces of both molds to form a cavity 14 therein. 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 cavity 14.

  On the other hand, in the molding die of the present invention, the cylindrical member is placed in the cavity 14 to form the plastic lens raw material liquid injection cavity 2. Since the plastic lens raw material liquid injection cavity has a non-circular shape, a molded body obtained by performing a curing reaction therein also has a non-circular shape.

  FIG. 3 is a cross-sectional view showing a state where the cylindrical member shown in FIG. 1 is disposed in the cavity shown in FIG. 3 is a cross-sectional view taken along line YY in FIG. 1 left, and the right view in FIG. 3 is a cross-sectional view taken along line XX in FIG. 1 left.

  As shown in the right figure of FIG. 3, the plastic lens raw material liquid is connected to 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 on the peripheral edge of the side surface of the cylindrical member. Is formed. It is possible to form a flow path by forming an opening on the side surface of the cylindrical member 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 cutout in the cylindrical member. In addition, forming the flow path by communicating the cutout or opening of the cylindrical member and the inlet of the gasket as described above is advantageous in facilitating the positioning of the gasket and the cylindrical member.

  In the embodiment described above, an annular gasket is used as a sealing member for fixing the sandwiched state between the mold and the cylindrical member by surrounding the periphery of the two molds and the cylindrical member. It is also possible to use an adhesive tape as a sealing member.

[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 non-circular plastic lens is obtained.
In the plastic lens manufacturing method of the present invention, the plastic lens raw material solution is cured in a cavity formed by sealing a non-circular through hole of a cylindrical member with two molds, that is, in a non-circular cavity. Thus, a non-circular plastic lens can be manufactured. 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, etc., so that a curing reaction of the curable component contained in the lens raw material liquid is performed to obtain a non-circular 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 and further removing the cylindrical member. 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. Since the shape of the plastic lens manufactured by the present invention is closer to the shape of the lens to be framed than the circular lens as described above, the amount of the portion removed and discarded as an unnecessary portion in the edging process. Can be greatly reduced.

  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 cylindrical member Cylindrical member having a through-hole whose cross-sectional shape is a rounded square (short diameter 52 mm, long diameter 72 mm) using polyethylene elastomer (Excellen FX, manufactured by Sumitomo Chemical Co., Ltd.), which is an olefinic thermoplastic resin. (Outer diameter 81.5 mm, height 17.5 mm) was obtained by injection molding.
A notch was formed by a cutter at the peripheral edge of the side surface of the formed cylindrical member.
Through the above steps, a cylindrical member having the shape shown in FIG. 1 was obtained.

(2) Assembly of molding die The cylindrical member obtained in the above (1) 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 coincided. Thereafter, two glass molds were fitted into the opening of the gasket, thereby assembling a mold 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 liquid was introduced into a plastic lens raw material liquid injection cavity formed by sealing the cylindrical member through hole with two molds, 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.

In Example 1, the shape of the lens taken out from the mold was the same shape as the through hole of the cylindrical member, that is, a rounded quadrangle with a short diameter of 52 mm and a long diameter of 72 mm. That is, a non-circular lens could be obtained. The thickness of the obtained lens was the same as the height of the cylindrical member. By removing unnecessary portions from the non-circular lens according to the frame shape of the spectacle frame and placing it in the spectacle frame, the spectacles can be completed.
For example, a circular lens formed by a molding die in which two circular molds are fitted and assembled in the gasket has a diameter of about 80 mm when the gasket is taken out. Compared to this circular lens, the volume of the non-circular lens is about 35% less. 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.

Claims (5)

Two circular molds facing each other at a predetermined interval;
A cylindrical member sandwiched between the gaps;
A sealing member for fixing the sandwiched state between the mold and the cylindrical member by surrounding the peripheral surfaces of the two molds and the cylindrical member;
Have
The cylindrical member has a through-hole having a non-circular cross-sectional shape, and the through-hole is sealed with the two molds to form a plastic lens raw material liquid injection cavity. Mold for plastic lens molding. The plastic lens molding die according to claim 1, wherein a cross-sectional shape of the through hole is a rounded square. The plastic lens molding die according to claim 1, wherein the sealing member is an annular gasket. The gasket has a plastic lens raw material liquid inlet on a side surface, the cylindrical member has a notch at a peripheral edge of the side surface, and the plastic lens raw material liquid is introduced into the cavity by communicating with the inlet. The plastic lens molding die according to any one of claims 1 to 3, wherein a flow path for injection 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, characterized in that a non-circular plastic lens is obtained.