JPH0623766A - Mold for laminate lens and production of its lens structure - Google Patents

Abstract

PURPOSE: To provide a direct casting method in which a glass plastic laminated spectacle lens structure is improved. CONSTITUTION: A composite body 18 is constituted of a glass element 12 and an organic polymer member. The edge of the member is protruded out more than the glass element 12 to form an extended section 20. A mold member 30 is constituted of a closed terminal 32 and a wall 36. An injection opening 34 is formed on the closed terminal 32. The wall 36 is formed of annular sections 38, 40 and 42 and terminated on a horizontal shelf 46 on the upper side of the wall. Sections 38 and 40 are connected together by a shelf 44. The mold member 30 is fixed with a member of a terminal body 18, and the body 18 is so inserted as to bend the extended section 20 behind the glass element 12. The body 18 is inserted into the mold member 30 until the body 18 is supported by the shelf 44, and the body is turned over and a laminated lens monomer is injected from the injection opening 34 and cured therein.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to glass plastic laminated spectacle lens structures and organic polymer molds used in the manufacture of such structures.

[0002]

2. Description of the Related Art US Pat. Nos. 4,793,703 and 5,014,
No. 712 (Flets, Jr.) describes a three-layer glass-plastic laminated spectacle lens structure. The lens comprises (1) an inorganic glass element, preferably photochromic glass, (2) a rigid organic plastic element, and
(3) It consists of a flexible organic adhesive thermoset or thermoplastic interlayer. According to US Pat. No. 4,793,703, the plastic element is selected to provide a coefficient of thermal expansion in the range of 200-700 × 10 ⁻⁷ / ° C. This relieves the severe stress conditions that tend to develop for more expandable plastics.

According to US Pat. No. 5,014,712, an adhesive interlayer is more firmly bonded to glass and plastic elements by having reactive groups on the surface of each element and the adhesive interlayer. This controls the subsequent delamination.

Generous application No. 07/82 filed on January 21, 1992 in the name of Dasher et al. And assigned to the assignee of the present application
No. 2,863 describes a continuous direct casting process for making laminated lens structures. In this way, one of the glass elements
One surface is provided with a thin flexible plastic adhesive layer. This forms a composite body that fits snugly into the tubular gasket. The monomer formulation is then cast onto the adhesive layer and cured to finish the laminated lens structure.

In addition to the patents mentioned above, please note the following US patents:

No. 2,542,386 (Beaty) describes introducing a monomer formulation into a gasket-type mold cavity through a flat nozzle.

No. 3,830,460 (Beety) describes the manufacture of organic plastic replica mold parts for glass or metal master molds. The replica member is incorporated into a conventional three-piece arrangement for casting organic plastic spectacle lenses. This patent teaches the selection of materials used to form the replica member.

No. 4,197,266 (Clark et al.) Describes molding an organic polymer lens between two molds to provide a reservoir of monomer and retain a filled cavity during curing. ing.

[0009] These patents do not disclose a direct casting complete one-piece organic plastic mold member. Therefore, it is thought that those patents have at most incidental interest.

[0010]

The tubular gasket disclosed in the Dasher et al. Family application is open at both ends. The composite body inserted into the gasket forms the bottom mold member. A rigid cover plate is placed over the upper edge of the gasket and the monomer to provide the upper mold member. It also creates the desired contour on one surface of the cured resin. The present invention seeks to improve the direct casting method of the Dasher et al. Application by providing a one-piece plastic mold.

[0011]

One aspect of the mold of the present invention is a one-piece organic polymeric mold having a top wall portion, a completely surrounding sidewall portion and an open bottom. The side wall has at least two completely surrounding portions with horizontal shelves for connection that function as stops for the composite lens member inserted through the open bottom. The lower portion of the sidewall is angled outward to facilitate entry of the lens member. To further facilitate the entry of the lens, a third portion of the sidewall is sloped outward at a larger angle to provide an outwardly flared shelf. The top wall part that completely surrounds the
It has an upright open entry that fills the mold with a curable monomer formulation.

The present invention is further an improved method of making a glass plastic laminated spectacle lens structure, the components of which are (a) a thin inorganic glass element, (b).
A rigid organic plastic element, and (c) a flexible adhesive intermediate layer, the method comprising: (1) applying a thin flexible plastic adhesive layer to the interior concave surface of the glass element to form a composite body; 2) inserting the composite into a mold member such that the peripheral edge of the composite body fits properly against the inner wall of the mold member and is sealed from the periphery; (3) on the concave surface of the composite body, Injecting the monomer blend to a depth at least as thick as the thickness of the organic plastic element, and (4) curing the monomer to form a laminated lens blank, including closed ends, open ends and sidewalls. The composite body is inserted into a hollow mold of a one-piece organic polymer having a side wall having an inner shelf surrounding the cavity and acting as a stop, the composite body being the front of the composite body. We are considering how to be inserted into the mold of the open end until it meshes with the rack of the side wall.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on the embodiments shown in the drawings.

The present invention provides a method of making a laminated glass plastic spectacle lens blank that is relatively inexpensive. FIG. 1 is a sectional view showing such a lens blank 10. The lens blank 10 consists of a glass element 12, a plastic element 14 and an adhesive intermediate layer 16.

The plastic element 14 was formerly an epoxy body, preferably cast and otherwise cured. The main feature of the invention described in copending application 07 / 822,863 is referred to as direct casting, ie casting and curing of element 14 as part of a continuous lens forming operation.
This includes casting and curing steps as part of continuous operation.

The present invention represents an improvement on the direct casting method and system of Dasher et al. More particularly, the present invention provides a one-piece organic polymer mold for use in a simplified casting process.

Adhesive layer 16 is provided by applying a thin flexible plastic layer over the inner surface of glass element 12, as described in the Dasher et al.
Forming eighteen. Thermoplastic urethanes that are preformed by extrusion as thin sheets are preferred. The sheet is on the order of 0.005 to 0.025 "(0.13 to 0.63 mm) thick, preferably 0.010 to 0.015" (0.25 to 0.375 mm) thick. As an example, an aliphatic polyether type urethane obtained from Thermedix under the trademark SG-85A is used.

Since thermoplastic urethane is preferred, the present invention will be further described in terms of applications such as materials for the intermediate layer 16. However, it will be appreciated that other thermoplastics and thermosets are also contemplated. These plastics include polyvinyl butyral, 1,4 butanediol, polyether polyols and aliphatic diisocyanates.

The composite 18 is preferably formed by applying an adhesive layer 16 to the glass element 12 as described in the Dasher et al. Briefly, the method consists of placing a glass element 12 on a heated pad and laying a sheet of thermoplastic urethane on the glass element. A vertical mutual plunger with a convex compression surface is mounted on the sheet in axial alignment with the glass element 12. Before applying the urethane sheet to the glass, lower the plunger to contact the urethane sheet for pre-stretching. The heated glass element is then raised to cooperate with the plunger to form the composite body 18 when the urethane sheet is applied to the glass. Reference is made to the genus application for details regarding the formation of the complex body 18, which application is included herein for that purpose.

When formed, the composite body 18 has excess thermoplastic urethane film that must be trimmed. As shown in FIG. 2, which is a side sectional view,
The excess film is cut, leaving a circumferential extension 20 beyond the glass element 12 of about 0.5 cm. This makes the glass element
Sufficient overlap is provided to be overlapped over the twelve edges.

FIG. 3, which is a sectional side view, shows an organic polymer member.
14 shows an improvement system for casting 14. The system comprises a composite body 18 and an organic polymeric type member according to the present invention generally designated 30. The mold member 30 is a completely unitary member.

The type polymer used must be a high temperature polymer having a melting point above the maximum temperature reached in the cure cycle of the monomer formulation. The polymer must also have a sufficiently low polarity so that it does not adhere to the lens polymer on subsequent cure. This eliminates the need for the release coatings currently required and avoids the adhesion of the coating to the glass member.

The organic polymer type member of the present invention is easily manufactured by injection molding from a relatively inexpensive material. Not only does this provide a disposable mold that is inexpensive to clean, but it also allows the lens geometry and type to be easily modified. For example, to make a variety of lenses, such as aspherical lenses, progressive lenses, and lenses with countersinks that are multifocal, only the injection molding machine equipment needs to be modified.

Accumulation of electrostatic charge usually occurs in polymeric materials, especially when the material is injection molded or cast. To avoid this in current mold parts, antistatic agents are included in the mold polymer. This is important to reduce the tendency of either the molded or cast lens to cause contamination of the material by the environment making the cast lens unusable.

Suitable materials, especially for use in extruding mold members, are polyolefins such as polypropylene and polymethylpentene. Also of interest are perfluorinated hydrocarbons such as FEP and polyvinylidene fluoride. However, fluorocarbons are more expensive and difficult to mold. For higher temperature curing, polymethylpentene is preferred due to its high melting point.
Polypropylene is easier to obtain and is therefore preferably used when the curing temperature does not exceed about 160 ° C.

The mold member 30 shown in FIG. 3 has a closed end 32. The inner surface of the closed end 32 has a shape that corresponds to the desired outer surface for molding the organoplastic lens element 14 but vice versa. A small inlet 34 for injection is formed in the mold 30, preferably at the edge of the closed end 32. The inlet 34 is
It acts as a means of introducing the monomer formulation into the mold 30 when the mold is inverted. It also acts as a reservoir for the monomer to flow into the mold as it expands during curing. An upstanding annular wall 36 begins around the closed end 32. The wall 36 closes the open space into which the composite body 18 is inserted and forms the closed upper end of the mold 30. As explained later, the mold 30
It can be turned over to prepare for casting. The composite body 18 then becomes the base or bottom of the mold 30.

The wall 36 preferably comprises three annular sections or bands 38, 40 and 42 which are fully formed as one piece. Portion 38 is the vertical portion of mold 30 that is perpendicular to the horizontal plane. When element 14 is cast into the mold and allowed to cure,
The portion 38 forms the edge or outer surface of the element 14. The wall 36 staggers at the upper edge of the wall portion 38, providing a shelf 44. The ledge 44 acts as a support for the composite body 18 when it is inserted into the mold. The intermediate portion 40 is inclined from vertical to the outside at a small angle, for example about 5 °. The wall portion 42 slopes outward from vertical at a larger angle, for example about 45 °. The wall 36 ends in a flat horizontal shelf 46. The wall 36 and the closed end 32 together form the mold 30.
The mold surrounds the cavity and is open above it.

In operation, the composite body 18 has an adhesive layer
16 is placed over the open end of the mold 30 so that it faces the mold cavity. The narrow extension 20 of the thermoplastic urethane adhesive layer 16 is
Leaning within shelf 46. Then the complex body 18
Pressure is applied to insert the body into mold 30 until it leans against shelf 44. Therefore, the composite body 18 forms a closed end on the mold 30 and becomes the base or bottom wall when the mold is inverted.

4A-4D are cross-sectional side views showing four stages during insertion of composite body 18. The figure also shows the wall 36
How the preferred structure of will facilitate the insertion of the body 18 will be described. FIG. 4A shows the first stage with the body 18 positioned on the mold 30 with the extension 20 positioned to lean against the shelf 46.
FIG. 4B shows the extension 20 folded back toward the annular end of the glass member 12 when the body 18 is pushed inside the wall portion 42. FIG. 4C shows the extension 20 hermetically folded against the end of the glass member 12 when the body 18 is further depressed into the wall portion 40. FIG. 4D shows the composite body pushed into its final position, ie, against the shelf 44.

The assembly shown in FIG. 4D is now flipped over to serve as cast molding. This is shown in FIG. 5, which is a cross-sectional view showing the preparation of the mold placed in the curing chamber. As shown in FIG. 5, a monomer formulation, preferably an epoxide formulation, is introduced through the currently upright inlet 34 until cavity 48, as well as inlet 34, are filled.

The properly supported assembly is now subjected to an appropriate curing step in known manner. For example, in the case of an epoxide formulation, a temperature of 55 ° C for 16 hours
Gently raise the temperature to 150 ° C and cool it to 150 ° C for 4 hours
A heat treatment cycle of holding at ° C is conceivable. This step cures the epoxide formulation and forms the resin member 14, thereby forming the desired laminated lens blank 10.

[Brief description of drawings]

1 is a cross-sectional side view of a three layer laminated glass plastic spectacle lens structure known in the prior art.

2 is a cross-sectional side view of a preferred shape of a composite lens body used in the manufacture of the structure of FIG. 1 according to the present invention.

FIG. 3 is a cross-sectional side view showing a direct casting system for producing the lens structure of FIG. 1 including an organic polymer type member according to the present invention.

4 is a cross-sectional side view of the system of FIG. 3 showing the steps of inserting the composite body of FIG. 2 into the mold of FIG.

5 is a cross-sectional side view of the system of FIG. 4 filled with a monomer formulation ready for cure.

[Explanation of symbols]

 10 Lens Blank 12 Glass Element 14 Plastic Element 16 Adhesive Intermediate Layer 18 Composite Body 20 Extension 30 Mold Member 32 Closure End 34 Inlet 36 Annular Wall 38, 40, 42 Band 44, 46 Shelf 48 Cavity

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Internal reference number FI Technical display location B29L 9:00 4F 11:00 4F (72) Inventor Frederick Ernest Nor New York, USA 14814 Big Flats Larkmont Av Inventor 1412 (72) Inventor Scott Keith Philhower United States Ohio 45230 Cincinnati Cambridge Avenue 6123

Claims (18)

[Claims] 1. A mold for laminated glass plastic spectacle lens structures, which mold is a one-piece organic polymer hollow body consisting of closed ends, open ends and sidewalls,
Such that one end of the side wall is fully connected around the closed end of the mold and the other end of the side wall surrounds the open end of the mold and receives a glass lens element in a cavity surrounded by the side wall. A mold sized to have an internal shelf that acts as a stop for the inserted glass element. 2. The mold according to claim 1, wherein a portion of the side wall on the opening end side of the shelf is inclined outward to facilitate insertion of a glass lens element into the mold. 3. A portion of the side wall on the open end side of the shelf comprises two completely surrounding portions, a first portion directly adjacent to the shelf sloping outward at a small angle, The mold according to claim 1, wherein the second portion is inclined outward at a larger angle. 4. The outer edge of the second portion is surrounded by a horizontal shelf, the inner diameter of the horizontal shelf being equal to the outer diameter of the adhesive layer on the glass element inserted into the mold. Mold according to claim 3, characterized in that it corresponds. 5. The mold of claim 1, wherein the closed end of the mold has an outwardly upstanding opening that serves as a reservoir and inlet / outlet for the monomer formulation. 6. The mold of claim 5, wherein the upright opening is at the edge of the closed end of the mold. 7. The mold according to claim 1, wherein the organic polymer is polyolefin or fluorocarbon. 8. The mold of claim 7 wherein the polyolefin is selected from the group consisting of polymethylpentene and polypropylene. 9. The mold of claim 1, wherein the organic polymer has a low polarity so that the lens polymer does not bond with the mold polymer during curing of the lens polymer. . 10. The mold according to claim 1, wherein the organic polymer has a melting point higher than the curing temperature of the lens polymer. 11. The organic type contains an antistatic agent to prevent accumulation of electrostatic charges.
Described type. 12. A method of manufacturing a glass-plastic laminated spectacle lens structure, the components of which are: (a) a thin inorganic glass element, (b) a rigid organic plastic element, and (c) a flexible adhesive intermediate. The method comprises: (1) applying a thin flexible plastic adhesive layer to the inner concave surface of the glass element to form a composite body; (2) a peripheral edge of the composite body having a mold member. Inserting the composite into a mold member so that it fits properly into the inner wall of and is sealed from the surroundings, (3) on the concave surface of the composite body at least as deep as the thickness of the organic plastic element A one-piece organic polymer having closed ends, open ends and side walls, comprising: (4) curing the monomers to form a laminated lens blank. Inserting the composite body into a hollow mold, the side wall having an internal shelf that surrounds the cavity and acts as a stop, the composite body extending to the point where the composite engages the side wall shelf. A method characterized by being inserted into the open end of the mold. 13. The method of claim 12, wherein sidewalls of the mold beyond the shelves slope outward to facilitate entry of the composite body. 14. The method of claim 13 wherein the side wall of the mold beyond the ledge comprises two annular portions, one portion sloping outward at a greater angle than the other. 15. After inserting the composite body into the mold, the mold is inverted and the monomer formulation is placed in a cavity surrounded by the sidewalls through an upright entrance / exit of the closed end of the mold. 13. The method according to claim 12, wherein the method is introduced. 16. The method of claim 15 wherein said monomer fills the reservoir and said cavity formed by said upright entry and exit ports. 17. The method of claim 12, wherein the organic polymer type comprises polyolefin or fluorocarbon. 18. The method of claim 17, wherein the polyolefin is selected from the group consisting of polymethylpentene and polypropylene.