JPH01500256A - Contact lens molding - Google Patents

Abstract

PCT No. PCT/GB87/00045 Sec. 371 Date Nov. 4, 1987 Sec. 102(e) Date Nov. 4, 1987 PCT Filed Jan. 27, 1987 PCT Pub. No. WO87/04390 PCT Pub. Date Jul. 30, 1987.A polyolefin mould for casting contact lenses from a polymerizable monomer composition which shrinks on polymerization, said mould comprising: male (50) and female (51) mould halves at least one of which has a flexible diaphragm portion (53, 54) which is shaped to provide a surface corresponding to a lenticular surface, said mould halves (50, 51), when closed together, cooperating to define a mould cavity (52) for receiving a volume of said monomer composition, at least one of said mould halves (50, 51) having a shoulder portion (55, 56) surrounding said cavity and shaped to engage with said other mould half to define an edge moulding portion of said cavity; whereby in use said diaphragm (53, 54) is deflected into said cavity under forces exerted on said mould by said monomer composition when polymerized in said closed cavity (52), thereby compensating for the shrinkage occurring on polymerization and avoiding the formation of bubbles or voids in the resulting lenses. In addition, the invention includes a method of casting contact lenses using a mould of the above kind.

Description

[Detailed description of the invention] contact lens shadow The present invention is a mold formed by two plastic half molds (half molds). Contact lenses are manufactured by casting a polymerizable 100% composition into a mold. 6. Further, the present invention relates to a novel shaped plastic for casting lenses. Packaged using stick molds and already formed mold parts The present invention relates to a system for manufacturing a lens.

Contact lenses are manufactured on a large scale from a pair of cooperating half-molds. The lens is cast within the formed closable mold. Closable mold system One thing that must be overcome when casting lenses from polymerizable polymers in the system The problem is that the monomer composition has to be The goal is to provide a means to Senzuma lumber used in the manufacture of contact lenses The materials generally exhibit volumetric shrinkage between 10 and 20%. Compensate for such shrinkage Failure to do so may result in unacceptably high waste rates and/or voids. This results in a poor quality product containing bubbles or bubbles.

Various methods have been proposed to solve the problem of shrinkage that occurs during casting of monomer compositions. has been done. These methods include an inflow into the cavity that is contracted and fills it. There are ways to provide a reservoir of anticipated thousands of materials (e.g. No. 2,006,091), however, the problem with this type of solution is that of monomer must reach the mold cavity through the confined area. However, the monomer tends to gel more rapidly in this confined region. It is about having quality.

One commercially successful solution to the shrinkage problem was found in British Patent No. 1. No. 575,694, taught by T. H. Chefart. . According to this Chef Art invention, one of the two halves of the mold (usually the male half) The split mold is provided with a visible peripheral rim or lip. These half-split models The mold is designed so that when the mold is closed, the flexible rim is aligned with the corresponding part of the other half of the mold. The mold cavity is designed to contact the surface of the mold cavity and define the perimeter of the mold cavity. thousand When contraction occurs during polymerization of the thumb, the flexible rim or lip (usually deforms inward) The two mold halves now touch each other slightly more closely than in the initial closed state. I think about it nearby. This slight increase in the proximity of the half-molds to each other in this polymerization stage The movement reduces the volume sufficiently to compensate for the shrinkage during polymerization.

In general and for many polymerizable materials, Scheffert's method is extremely effective. It has been a huge commercial success. However, mainly the edge of cast lenses There are several disadvantages depending on the manner in which it is formed. Chef Art Mold's Deliqué Great care must be taken to satisfactorily mold the soft flexible rim or lip area. Flexible rim makes it easy to fit the two mold halves together when needed and in use This can result in poorly shaped edges and Such edges often require mechanical polishing to make them acceptable to the eye. High quality record When manufacturing lenses, edge polishing is required unless extremely high rejection rates are tolerated. It is. Sanding can be done using many wood-friendly materials in dry condition; however, this method Not only would a separate processing step be required, but the lens would also be damaged during the drying process. There is a risk of loss.

Additionally, some lens materials, such as silicone rubber and fluorocarbon polymers, It cannot be polished because it is not hard enough.

One of the features of the present invention is that one of the mold halves has a flexible rim or lip. The present invention relates to another method of solving the problem of compensating for shrinkage without providing a loop.

British patent specification 'tS2048758 states that the male and female parts of the mold are A contour with a horizontal shoulder-like peripheral mating surface on top of the lead portion. discloses a polypropylene mold for lenses. These shoulders are finished A load of 2 to 3 bonds was applied to the male part to avoid forming a blemish around the lens. Sometimes formed as an interference fit to seal tightly together. This kind of mating The purpose of using the lens is to eliminate variations in lens thickness around the lens. The two parts of the mold must fit together with the same degree of precision.

According to the invention, a female lens having a curved surface defines the anterior surface of the lens to be molded. Introducing a measured amount of the polymerizable monomer composition into the half-mold and placing it after the lens. Close the mold with a male half-mold having a curved surface defining a lateral surface. , consisting of polymerizing a 1,000-tonne composition and removing the resulting lens edges. A closed mold portion defining a curved surface on one of said mold halves. at least one of the mold halves, including a non-flexible shoulder forming the periphery of the surface; A diaphragm is formed on the curved surface, and the diaphragm portion is The suction force generated by the shrinking mold during polymerization causes the other half of the mold to B moves towards the resisting surface and thus fills to compensate for the resulting volume contraction. Inject the contact lens in a fully flexible, closable plastic mold. A method to type is provided.

The present invention mainly provides contact lenses made from polymerizable 100% polymer compositions that shrink during polymerization. A polyolefin mold for molding, the mold comprising male and female halves. Consists of segmented molds, at least one of which accommodates a lenticular surface The half-split mold has a diaphragm portion shaped to have a flat surface. a mold cavity for containing a volume of said monomer composition when closed together; at least one of said mold halves cooperates to define a shoulder joint. a shoulder portion surrounding the cavity and the other half; The shape is such that it engages with the split mold to define an edge molding portion of the cavity. and the diaphragm is configured to control the diaphragm during polymerization within the spaced cavity. Deflected into the cavity by the force generated on the mold by the Zimmer composition Also includes polyolefin molds that are sufficiently flexible to do so.

The main difference between the present invention and the Chef Art method described above is that the curved or lenticular The shoulder part of the mold surrounding the square mold surface is compared to the diaphragm part. The diaphragm portion of the mold is essentially non-yielding and the required volumetric contraction is due to bending of the diaphragm portion of the mold. be compensated by the

These diaphragm portions of the mold are manufactured from relatively thin plastic material. These parts, in combination with other dimensions, including the diameter of the mold halves, form the two halves. The central region of the split mold can be deflected to eliminate shrinkage.

The shoulder part of the mold has a cavity that is liquid-tight when the mold halves are put together. Designed to be sealed. The shoulder part has two half-split moldings. Shaped so that when the shoulders are brought together, the contact area between the shoulder parts is essentially a line contact. It is preferable that the heifer split mold cylinder has a slight barb. It is preferable that the We can guarantee that the formed mold will remain.

Preferably, the half-mold is significantly larger than the lens being molded. Some effects can be obtained by doing this, for example, on the top of the mold cavity. On the one hand, an annular gap is obtained between the mold halves. This annular gap Acts as a reservoir, this reservoir ensures that the mold is completely filled when the mold is closed. We guarantee that the This gap acts as a chamber in which the molding flash can be locked. Ru. After opening the mold, the flash preferably rests on the male mold; can be guaranteed by forming a rough surface on the outer part of the bull split mold in this area. Wear.

Another big advantage of using large half-molds is that the The objective is to easily hydrate the shaped lens. After hydration, the female half-split mall hydration by sealing the tear-off gap or lid against the flange of the It is possible to mold the package of the lens.

Further features and advantages of the invention will become apparent from the following description and the accompanying drawings.

Figure 1 shows the two halves of the mold just before closing (UK Patent No. 1.5). 75494) side sectional view of the chef art mold, The second section is a chef art mold with two half molds completely closed. FIG. 3 shows a second embodiment of the mold according to the invention with %x. A diagram similar to the diagram, FIG. 4 is a side sectional view of a second embodiment of the mold according to the present invention; Figure 5 shows Figure i8a and Figure 8 with the tear-off lid fitted to form the package. A side view of the mold shown in figure b, Figures 6a and 6b show the separated lid and cow of the package shown in Figure 5. The cross-sectional view of the split mold, Figure 7a, is the chef art mold shown in Figures S1 and 2. FIG. 7b is an enlarged partial view of the edge of the lens mold in the mold according to the present invention. A similar diagram of a lens cast from Figure i7c, figure 7d and figure 7e show the edges of the lens in the mold according to the invention. Figure 8a is an enlarged partial view of Figure 4 of the third embodiment of the mold according to the present invention. Diagrams similar to those shown; Figure 8b is a plan view of the mold shown in Figure 8a.

Referring to the drawings, Figures 1 and 2 show the male half model of the Chef Art mold. female half mold 1 and female half mold 2 are shown, and half mold 1 and female half mold 2 are shown respectively. Surfaces 3 and 4 of 2 are polished surfaces, each having a maximum curvature. Define the base curve and prescription curve of the final cast lens. flexibility The rim 5 is integrally molded on the male half mold. When the mold is closed , the rim 5 abuts the surface 4, and the rim height "d" is equal to the initial depth of the mold cavity. Define the area and surrounding area. The 100% composition introduced into the mold cavity polymerizes. When this occurs, a contraction of the volume of the composition occurs. As a result, the rim 5 is as shown in FIG. deforms inward, and the two half-molds approach each other during the polymerization of the 1000 ml composition. Therefore, the molds are separated by a distance "x". At this distance, the lens is hard. Indicates the final thickness of the lens if bought, or if the lens is woody and subsequently hydrated, Shows part of the thickness (usually about half).

As can be seen from Figure 342, the rim 5 also deforms inward in common. As a result, the mall When the door is opened, the lens is usually held on a male half-mold. The rim is polymerizing The periphery of the lens is deformed unevenly, resulting in defective edges. Figure 7a is before polishing. A representative edge portion of a lens molded using Chef Art Mold is shown.

Close the mold, fill the mold cavity with the 1,000 ml composition and close the mold When a load is applied, the applicant's pending British patent application 'f%8606324 (publication) 2172839), the flanges 1 and 18 were deformed, and both Can be welded. The closure method in this embodiment is described in British Patent Specification No. 2172B39. It may be carried out as described in .

Volumetric shrinkage is caused by the suction or vacuum force created by the shrinkage of the polymer composition. This is compensated by the bending of the parts 19 and/or 20 which act in a flammable manner. subordinate Therefore, the position of the inner surface of portion 19 on the male half-mold is The position will be as indicated by the dotted line in Figure 3. Diaphragm part of mold The amount by which the lens is displaced depends on the nature of the polymerizable composition (including volumetric contraction during polymerization) and Depends on the volume of the mold cavity. Generally, the amount of displacement is about 10 to 40 microns, For example, 10 to 25 microns.

The mold according to the invention uses conventional molding temperatures, pressures, speeds and residence times. It is molded using an injection molding method. Each mold is typically a "one-way" mold be. That is, after a lens is cast in a mold, the mold must be discarded or In connection with FIGS. 5, 6a, and 6b, the lens pads will be described later. Used to form cages.

Compared to the chef art mold, the solid shoulder portion 15 has a flexible rim 5. You will notice that it has been replaced. As shown in Figures 4, 8a and 8b. In some embodiments, thickening of the molding material in the shoulder area or corresponding area may be used. This makes it possible to increase the rigidity in the shoulder area. Furthermore, Fig. 4, Fig. 8a and Another mating surface is formed on the mold half, as described below in connection with Figure 8b. This increases the strength of the entire mold.

Models having the general shape shown in Figures 3 and 4 and an inner diameter of approximately 9 to 1 (ln+) 1 to 1.5 mm when using a polypropylene mold It was found that the thickness of the material was satisfactory.

Figure 'fS4 shows a '=2 embodiment of a mold manufactured according to the invention, which The embodiment (and the embodiment shown in Figures 88 and 8b) is currently A preferred embodiment is shown below. As you can see, the overall size of the mold is shown in Figure 3. substantially larger than the mold shown in .

The purpose of this is to mold the female half-mold 51 in a later step in the process for molding lens hydration. The goal is to make it possible to use it as a container for personal use.

The mold shown in FIG. 4 has a bull splitting mold 50 in common with the mold shown in FIG. and a heifer split mold 51 which, when closed together, measure the A mold cavity 52 is formed for accommodating a volume of polymerizable polymer. . This cavity 52 has two cooperating curved lens molding parts 53 and 54, the lens molding portions 52 and 54 are flexible and have a thickness of, for example For example, 0.6-1.4 ar1! , preferably as thin as 0.8 to 1.21 . The periphery of mold cavity 52 is defined by cooperating shoulder portions 55 and 56. The cooperating surfaces of these shoulders form a liquid-tight seal when the mold is closed. The shoulders 55 and 56 are slightly inclined to each other so as to be in substantially line contact while Ru. As described below with reference to Figures 7C, 7d, and 7e, the A slight undercut or barb is formed on the inside edge 5 of the slider 56. This means that when the mold is opened, the hardened molded lens is exposed to the female half of the mold. Guaranteed to remain in the split mold.

Correctly aligning the mold while closing is important for male and female split molds. Further on the upper portion and on the axial surfaces of the shoulder portions 55 and 56 are axial alignment tables. This is ensured by providing surfaces 58 and 59. Open while the mold is closed. Surfaces 58 and 59 initially serve to align the mold halves, but when the mold As it continues to close, surfaces 60 and 61 form the final part of the mold halves that hold them together. The steps can begin to work together to ensure accurate axial alignment of the mold halves. be understood.

The geometry of these two half molds is approximately It is adapted to close along a radially extending cooperating surface.

The outer diameter of shoulder 55 is smaller than the inner diameter of shoulder 56, but these two dimensions The mold halves are slightly pressed together to create a sliding, aligned fit when the mold halves are closed together. They are just different.

As clearly seen in FIG. 4, the male mold wall portion 62 is located between the axially aligned surfaces. separated from the corresponding wall portion of the cow splitting mold in the area of . This will cause the acts as a filler and ensures that the mold cavity 52 is completely filled during the mold closing operation. An annular chamber 64 is formed to ensure that the outside of wall section 62 The side surfaces may be roughened, for example by forming a series of snatch rings 65 on the outside surface. face. This ensures that when the mold is opened, the molded lens and chamber 64 The point of cooperation between shoulders 55 and 56 is the connection with the hardened excess material locked therein. and the excess cured material remains attached to the outer rough surface of the wall portion 62. We guarantee that.

The upper ends of the mold halves 50 and 51 are provided with mold flanges 17 of FIG. and flanges 66 and 77 similar to 18 are formed, but the flange portion There are functional differences in the structure of The half-split mold shown in fS3 figure changes the top flange. Our British Patent Application No. 58606324 (Publication No. 217283) When taken together as described in the specific embodiment described in No. 9), the embodiment of FIG. This eliminates the need to deform the top flange. As can be seen from Figure 4, the flange 67 includes an upwardly extending hole disposed through a corresponding hole 69 in flange 66. A beg 68 is formed that extends. There are four pins or vegs around the flange. Although uniformly distributed, this number can obviously be varied. Top of flange 66 When the mold is closed by a predetermined closing load applied to the They are joined together by deformation 68. This means that the protruding portion of the beg 68 can be inserted into the bottom. This is done by the welding head forming the bottom, which can significantly distort the flange It can be welded to the top portion of the flange 66 without any need for welding. (The strain on the flange is almost This method eliminates the stresses that can be caused by deforming the top flange. Top flange if polymerization temperature induces relaxation of residual or applied stress A modification of the is required. During injection molding, residual stress occurs in both halves of the mold, causing the mold to close. Applied stress results from the application of chain loads. Relaxing one of these two types of stress For example, relative movement of shoulders 55 and 56 may occur, resulting in an unacceptable seal or and lens edge shape.

Referring to Figures 7a to 7e, these figures show the parts manufactured by the Chefart method. Figure 3 shows the shape of the molded edge of a lens made according to the invention compared to the edge. No. Figure 7a shows a typical edge profile formed by the Chefart method. As can be seen from 7a[], after the lens has hardened, the flexible rim 5 is bent inward, The cured lens is then held onto the top of the male mold 1. bull split mold Apart from the occasional problem when removing pre-molded lenses from An edge having a wafer edge of 7° and a recessed rim 71 results. mosquito This edge shape is generally not satisfactory as it causes discomfort to the wearer. It is usually ground to form an edge profile as shown in Figure 7b. Remove any uneven edges on the lens, as shown in Figure 7a, that must be polished. Therefore, the lens surfaces 140 and 141 within the area of the edges are polished to create a rounded edge. forming smooth surfaces 140 and 141 ending in diprofil 143 . This requires extra processing steps that are preferably avoided in large-scale lens production. Essential. The reason for this is extra cost and dirt and inaccuracy. It is both the cause and the cause.

Referring to Figure 7C, this figure was produced using a mold as shown in Figure 3. This shows the type of edge blow fill produced. This lens is shown in Figure 7b. 7a, but has a relatively sharp peripheral edge 2 compared to the original shown in FIG. In contrast to azaleas, they are almost uniform around the circumference of the lens, so they are comfortable for the wearer.

Sanding smooths out uneven edges, but sanding removes unevenly formed edges. It should also be noted that it is difficult to completely correct. Edge 73 flat or a naturally rounded part that comes into contact with the eye, and such a surface is generally comfortable. It is understood that However, the uneven surface is designed to prevent irritation to the lower surface of the eyelids. It is preferable to space the merging points away from the convex surface of the lens.

Additionally, there are practical advantages to locking the pre-molded lens within the heifer split mold. These improvements can be achieved by improving the shape of the cooperating parts of the mold. It will be done.

Referring to Figure 7d, this figure shows a slight undercut on the shoulder of the heifer split mold. - shows a situation in which a cut 75 is formed. This undercut is just a little For example, angle B can be approximately 10° from the axis of the lens. Undercover like this If the molded lens is left blank, the molded lens will remain in the female half mold, causing damage to the edges. It is easily released by hydration without being released. In the H7d diagram, the shoulder portion 74 is cooperates with the lenticular surface 76 of the male mold, so that the edge 7 is a concave surface of the lens. approach.

Figures 8a and 8b illustrate the presently most preferred embodiment of the invention. be. The mold shown in these figures is similar to and equivalent to the mold shown in Figure 4. Parts are given the same reference number. The main difference is that it houses the second reservoir 102. A peripheral portion 101 is located between shoulders 55 and 56 and includes a peripheral portion 101 within this reservoir portion. The point is that a snatch ring 65 is formed on the male mold.

0.5 mm between the wall portions 62 and 63 to form a reservoir 64. The gapped surfaces 6o and 61 are slidingly fitted and have a length of approximately 1 to 1.5 cm. Dimensioned to form a working surface. Similarly, surfaces 58 and 59 have approximately 1 Form a cooperating sliding guide surface 5-3 mm long, 1.5-2 mm above the acid mold are notched to form a 3-5° external lead taper of approximately 15-2 mm. Ru. The diameter of the lens cavity is determined by the desired diameter of the lens and is usually zero-gauge. For soft contact lenses that are molded as lenses, this diameter is between 8 and 10 mm. within range. Dimension d1. Typical dimensions of d2 and d3 are each approximately 15.2 0 and 30o+m between surfaces 58 and 59 and between surfaces 60 and 61. for sliding contact and some angled surfaces formed in the hollow part of the mold. As a result, the strength of the entire mold is increased outside the diaphragm portions 53 and 54. As can be seen from the zab diagram, the flange 66 has a veg. A hole 69 is formed for receiving 68 . The hole 69 has a sufficient diameter, especially in the peripheral direction. Provides a gap and some tolerance when the two half molds are brought together. It is now possible to

The preferred lens profile is shown in the iTe diagram. This diagram is an iBa diagram. Shows the edge profile that occurs when molding a lens using the mold shown. However, the same considerations apply to the mold shown in FIG. Is it an i7e figure? As can be seen, the edges are formed by the cooperation of the shoulders 55 and 56. Show The undercut or barb 55 (angle ), but the shoulder 56 is perpendicular to the axis of the lens. It is inclined to the plane. Since it has a top Rashid 78, the concave and convex surface is a concave part of the lens. It merges at one edge 79 between the convex surfaces. This requires polishing No extremely comfortable molded edges. The surface of landfing 8 is a radial plane. It may be tilted by an angle of approximately 4° to 10° (equivalent to angle α) relative to the It is sufficient that the cooperating parts of the routers 55 and 56 are in line contact. Shoulder 55 and 5 The dimension X of the cooperating part 6 is important to some extent, and should be approximately 0.1 to 0.2 mm. It is preferable that

Theoretically, the diaphragm part of the male and female half mold is a polymeric lens molding. They must bend equally under the stress created by the composition (they are (provided that it is the same thickness), but in fact, using certain injection molding methods, the male It has been found that substantially all of the movement occurs within the diaphragm of the mold. this The reasons are not completely understood. However, the effect of injection pressure difference At least a contributing factor, the diaphragm of the male mold is inherently slightly It is considered more flexible. Using a specific molding tool, the molding pressure can be applied to the female mold. 50 bar for the male mold and 30 bar for the male mold. ability was obtained. The molding temperatures are virtually the same, with barrel temperatures around 210°C and bolts. The star was cooled to about 40°C. These molding pressure differences (1) (female mold pressure difference) The higher the molding pressure, the greater the residual stress. Therefore, it is expected that the resistance against external loads will also increase. The real reason for this difference Whatever the suitable. Does this make it easier to predict the curvature of the cast lens surface? It is et al.

According to the invention, the shape of the edge is more predictable (at this point during casting the mold part There is no need to polish the edge surface anymore (as there is no movement of When implementing the present invention to manufacture drogel lenses, the cast lenses are made after opening the mold. The mold containing the female halves can be immediately immersed in hydration liquid. The lens is split into male half mode. Locking within the shield prevents damage and contamination during handling. Surprise In particular, hydration of the cast lens while locked in the female half-mold is As long as it is carried out in a suitable manner, it will not cause distortions caused by non-uniform hydration.

Mold opening and lens hydration can be mechanized. Therefore, the mold Place the mold on the feeder and orient the mold so that the mold flange is at the top. the mold into the separation station along the track. Guide and pneumatically weld the weld between the male and female flanges at the separation station Cut with a driving knife, raise the male molds, and remove these molds with suction pressure. You can do it like this. Next, remove the female half mold containing the locked molded lens. , placed into a tray by a vacuum-operated extraction unit, and from this into a hydration device. I can do it.

By positioning the mold so that there is significant space for the hydration fluid, The female mold cavity can be separated into two halves without the risk of the lenses popping out of the female mold cavity. The lens can be appropriately hydrated within the mold. Lenses are usually made of cast polymer. You can achieve satisfactory hydration by changing the hydration solution several times (for example, 4 to 5 times). Wear. Gradually decreasing the concentration of the saline hydrate in successive aliquots of fluid Preferably, this reduces the risk of stress cracks forming within the hydrated lens. This is because it seems to be gone.

Therefore, in carrying out the method of the present invention, a lens is poured into a mold cavity. mold, open the mold after appropriate polymerization and curing time, and then separate the female halves. Immerse it in the hydration bath while it is still attached to the mold. Dilute the hydrated lens in salt water solution After collection from a representative number checked for quality and fidelity to specifications can. However, due to the predictability of the method, each individual lens should be checked one by one. It is not necessary to check. The reason is that all lenses are manufactured from the original mold. This is because they are known to have the same optical properties within tolerance limits. Pre-molded The lens remains in the female half-mold from the casting stage to the final inspection, so there is no need to remove it. There is also less damage or contamination from handling.

In carrying out the present invention, a plasma arc is applied to one half of the mold. Other methods can also be employed, including radiation or electron beam irradiation. How to be afraid This is because the method works to ensure that the lens adheres to the half-split mold. .

Another advantage of the mold shown in Figures 4 and 88 and 8b is that the cow splitting mold This means that the final lens bag can be molded later. . Thus, with reference to FIGS. 5, 6a, and 6b, a suitably shaped lid 80 The package is made using the acid mold cavity 51 as a container closed by can be molded. Packaging contact lenses, especially hydrated contact lenses When storing lenses, avoid contamination from outside sources or drying and shrinkage of lenses during storage. escaping liquid or concentrating the stored solution and the user's It is important that the package is sealed to prevent eye irritation. No. In the embodiment shown in Figure 5, pulling the tear peg or tag 81 allows the opening. A tear N8o is provided which can be used. The structure of this N8o is clear from Figure 6. clearly shown. This 58° is made of sealable or heat weldable material, preferably Polypropylene or other materials that can withstand sterilization by autoclave heating or irradiation. It can be molded from other plastics. Polypropylene has a hydration contour autoclave at a temperature within the range of 120°C that is satisfactory for sterilizing lenses. It is an excellent material of choice because it can withstand heating. This N8o has A circumferential notch 82 is formed and the peg or tag 81 can be pulled and torn. The circular part in the center of the lid can be removed.

A circular rib 83 is formed on the lid outside the circular groove 82. This rib is female positioned to cooperate with a corresponding circular groove 84 in the flange 67 of the half mold. The shape of this rib collects the energy of the ultrasonic welding tool applied to M2O. A lid is placed on the flange in the center and in the region of the rib 83, that is, in the corresponding circular groove 84. Also works like welding. Ultrasonic welding simultaneously disperses liquid from the contact area and Ultrasonic welding is also preferable because it localizes and reliably welds the cooperating parts. That is, a female half-section model containing an expanded hydrated lens immersed in an isotonic saline solution. Fit the lid to form the packaged lens from the hydration station. This method is particularly preferred as it means that you can pass directly to the matching station. be. After packaging, the lenses are autoclaved to a temperature within the range of 120°C. The entire package is heated to sterilize it, inspected at the end, and shipped to the user. It is preferable that the 0 dimension r1. r2. Typical values for r3 and r4 are approximately 17.2 2.30 and 32 mm, and the preferred total depth of the heifer split mold is approximately 12 mm. ~! It is 5mm.

This is related to the use of cow split molds for molding soft contact lenses. This system uses a lathe inside a concave container. Packaging soft contact lenses manufactured by spray hydration Therefore, it can be improved and used.

The method of the invention applies to hard lenses such as polymethyl methacrylate, hard gas Transparent fluorocarbon and silicone rubber lenses and HEMA and its components parent trees, including soft (hydrogel) lenses, including polymer-based lenses; It can be used to cast hydrophobic or hydrophobic lens compositions. Typical lens molding port As a rimmer, U.S. Pat. No. 4,469,646, U.S. Pat. No. 9524, No. 3699089, No. 3700761, No. 3822089, and British Patents Nos. 1385677, 1475605 and 213883. This is the polymer described in No. 1.

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Claims (28)

[Claims] 1. A female half-split mold with a curved surface defining the anterior surface of the lens to be molded. A measured amount of the polymerizable monomer composition is introduced into the lens and the posterior surface of the lens is defined. Close the mold with a male half mold with a curved surface that defines the monomer polymerization of the composition and the resulting closure defining the edges of the lens. The curved mold part wraps around the curved surface on one of the mold halves. curvature of at least one half of the mold, including the non-flexible shoulder that constitutes the A diaphragm is formed on the surface, and the diaphragm portion is collected during polymerization. The opposing surface of the other half mold due to the suction force created by the shrinking monomer. sufficient flexibility to move towards the How to cast contact lenses in a closable plastic mold . 2. Each of the half-mold molds has a periphery of one of the curved surfaces. 2. The method of claim 1, wherein an inflexible shoulder is formed. 3. The shape and placement of the shoulder is determined by the area of the shoulder when the half mold is closed. Claims where the contact between the mold halves within the area is substantially line contact The method according to item 1 or 2. 4. When closing a half-split mold, the first contact is between the shoulders or between the shoulders. 4. A method according to claim 3, in which the curved surface of the half-mold is formed. 5. The suction force created by the monomer composition during polymerization causes the male half mold to according to any of the preceding claims, wherein the mold is deformed into the mold cavity. Method. 6. Due to the interaction between the axially aligned surfaces on a portion of each half mold According to any of the preceding claims, providing precise control of the alignment of the closure mold. the method of. 7. The process of maintaining the half mold by a closing load during the curing of the monomer composition A method according to any of the preceding claims, comprising: 8. By joining the mold halves together in areas spaced from the curved surface. 8. The method of claim 7, wherein the half mold is held closed. 9. The polymerized monomer is hydrophilic and the mold cannot be opened after the monomer has hardened. , the polymer is hydrated while the cured molded lens remains locked in the female half-mold. 9. The method according to claim 7 or 8, comprising: 10. Close the top of the female half-mold with a removable cap, thus keeping it in the aqueous medium. of claims including forming a sealed package containing a hydrogel lens in The method described in Scope Item 9. 11. Claims for joining the cap around the periphery of the female half mold by ultrasonic welding The method according to item 10. 12. Kill the lens by heat treatment or irradiation while in place in the package. 12. A method according to claim 10 or claim 11, comprising the additional step of culturing. 13. Casting contact lenses from polymerizable monomer compositions that shrink during polymerization A polyolefin mold for Consists of male and female half molds, at least one of which is a lens. a diaphragm portion shaped to have a surface corresponding to the zigzag surface; The split molds contain a volume of said monomer composition when closed together. working together to define a mold cavity, At least one of the half-split molds has a shoulder portion, and the shoulder portion surrounds the cavity and engages the other mold half to open the cavity. The diaphragm is shaped to define an edge forming portion of the tee; The monomer composition when polymerized in the closed cavity molds the mold. The polymer is sufficiently flexible to deflect into said cavity under the forces generated above. olefin mold. 14. Each of the male and female mold halves has a flexible diaphragm portion. The mold according to claim 13. 15. Shoulder part on one half-mold and on the other half-mold The engageable parts are such that when the mold halves are closed, the contact in the area of the shoulder is key. Shaped to provide a substantial line contact forming a fluid-tight seal in the cavity The mold according to claim 13 or 14. 16. Each of the male and female half-molds is provided with a shoulder section, which The angle the shoulder makes with the axis of the mold is such that the shoulder is substantially tangent to the mold closure. 16. The mold of claim 15, wherein the mold is slightly different so as to provide tactile bonding. 17. Casting contact lenses from polymerizable monomer compositions that shrink during polymerization A polyolefin mold for Consists of male and female half molds, each of which has a lenticular surface. The mold halves are shaped to have corresponding surfaces, and the mold halves are closed together. a mold cavity for accommodating a volume of said monomer composition when pressed; and at least one of said half molds defines a shoulder portion. The shoulder portion surrounds the cavity and connects the other half of the molding. and is shaped to engage with the edge molding portion of the cavity to define an edge molding portion of the cavity. Therefore, during use, the diaphragm part of the male mold is inside the closed cavity. The monomer composition is subjected to the force generated in the mold during polymerization. Polyolefin mold deflected into the cavity. 18. The mold halves have mutually engageable shoulder portions, and these shoulders The parts are designed so that when the mold is closed, the contact between the mold halves is essentially a line contact. 18. The mold according to claim 17, which has a hollow shape. 19. The female half-mold has a shoulder portion that surrounds the molded portion of the lenticular surface. , the female half mold has a hardening inside the female half mold when the mold is closed. A barb is formed in the region of the shoulder portion so that the lens can be retained therein. Molds listed in any section of the range. 20. The separate male and female mold halves have axially extending matching surfaces. The mold according to any one of claims 13 to 19. 21. on the male half-split mold so that the burr attaches preferentially to the male half-split mold. Claims 13 to 20, wherein a rough surface portion is formed on the outside of the lens-shaped molded portion. The mold described in any of the sections. 22. Contains a pair of generally cup-shaped interengaging male and female half molds , each half-mold fits tightly against the flange of the other half-mold when closed. Molding according to any one of claims 13 to 21, having adjacent flanges. Do. 23. Protrusions are formed on the flange on the female half mold, and these protrusions By deforming the protrusions, the male and female halves can be held together. A mold according to claim 22 passing through a corresponding opening in the other flange. . 24. The protrusion may be partially melted or placed in front of the flange of the male half mold. The mold according to claim 23, wherein the protrusion is deformed by welding the protrusion. . 25. It has a generally cup-shaped body portion formed from a polymer of propylene; Tearing of the propylene polymer hermetically sealed to the rim of the main body. Contains a container with a lid, the resulting sealed package is fitted with sterilized lenses and and an aqueous storage solution. 26. Claim 2: The main body portion is a female half-split mold into which the lens is cast. Packaged lens according to item 5. 27. Claim 25 or 3, wherein the lid is attached to the main body part by ultrasonic welding. 27. The packaged lens of paragraph 26. 28. According to any one of claims 25 to 27, the lens is a hydrogel lens. Packaged lenses as listed.