HK1003029B - Process and device for the production of moulded objects - Google Patents

Description

The invention relates to a process for the manufacture of moulds, in particular optical lenses and specifically contact lenses, as defined in the general concept of the respective independent claim 1 and a device for the manufacture of moulds, in particular optical lenses and specifically contact lenses, as defined in the general concept of the patent claim 27.

Contact lenses which can be produced in large quantities are preferably produced by the so-called moulding process and especially by the full-molding process, in which the lenses are usually produced in their final form between two moulds, so that neither subsequent processing of the lens surfaces nor edge processing is required.

In these well-known moulding processes, the geometry of the contact lens to be manufactured is determined by the mold cavity, the edge of the contact lens is also determined by the shape, which is usually made up of two mould halves, and the geometry of the edge is determined by the contour of the two mould halves in the area where they touch.

To make a contact lens, a certain amount of fluid-capable starting material is first introduced into the female mould halves. The mould is then closed by applying the male mould halves. Usually, the starting material is slightly overdosed so that the excess amount is displaced when the mould is closed into an overflow space that is connected to the mould cavity to the outside. Subsequent polymerization or interconnection of the starting material is done by irradiation with UV light or by thermal expansion or another non-thermal method.

The moulds are manufactured by injection moulding and are used only once (disposable moulds). This is partly because the moulds are partly contaminated by the excess material, are damaged when the contact lens is removed or are irreversibly deformed in parts.

In addition, the injection moulds can be subject to variations in dimensions due to variations in the manufacturing process (temperatures, pressures, material properties) and to a loss of moulds after injection moulding. These massive changes in shape can lead to variations in the parameters of the contact lens to be manufactured (refractive index, diameter, base curve, center thickness, etc.), which can lead to a deterioration in the quality of the lenses and thus to a reduced yield. If there is insufficient insulation between the mould halves, the excess material is not cleanly separated, which leads to the formation of so-called contact lenses.

In particular, due to the quality requirements of the contact lens rim, the molds are used only once, as some deformation of the molds in the contact area cannot be excluded with certainty.

A method for producing moulds such as boards or plates that include a core surrounded by a mantle is known from US-A-4,712,765. In this method and the associated device, a pre-formed core is introduced into a mold that includes a base part and a cover. A gap corresponding to the thickness of the mantle extends around the core introduced into the mold. A prismatic gap, located outside the actual mold cavity between base part and cover but connected to the mold cavity, inserts the material for the mantle into the mold cavity.

US-A-4,693,446 describes a process for manufacturing plastic lenses. The lens is manufactured by means of two moulds, between which a special seal defining the edge of the lens is placed. For example, the cavity formed by the two moulds and the seal is filled in such a way that two holes are provided in the seal. Through one of the holes the material is introduced, the other hole allows the escape of air in the cavity while the cavity is filled.

EP-A-0.484.015 reveals a method for the manufacture of lenses intended for the eye, such as contact lenses and intraocular lenses. The manufacture of the lenses is carried out by dispensing monomer into a female mould and then closing the mould with the help of the male mould. The closing of the male mould is carried out in such a way that when the male mould is moved on to the female, the male mould is directed to or centred on the side walls.

US-A-4,113,224 describes another moulding process for the manufacture of contact lenses, among others. This method uses a mould whose cavity is not completely closed but is connected to a reservoir channel (overloop) surrounding the cavity via a thin ring gap. The ring gap allows material to flow from the reservoir into the mould cavity during the interlocking process to compensate for the relatively large volume loss of the commonly used lens materials.

In order to ensure that material flows back into the mould cavity, at least initially, the material in the mould cavity is irradiated only in a central area smaller than the diameter of the mould cavity, or exposed in this central area to a greater radiation intensity than in the peripheral area of the mould cavity surrounding this central area. After the connection has begun and progressed to a certain extent, however, the material in the peripheral area with the adjacent mould and the mould in the reservoir are further processed in such a way that the material in contact with the surrounding ring and the surrounding rings are completely removed and the mould is subsequently treated with the necessary radiation, and the mould is then removed from the surface of the mould cavity.

Another problem with the manufacture of the moulds described above is that air may be introduced into the mould when it is closed, but this causes the lens to be sorted out as a panel during the subsequent inspection (quality control).

It is therefore a task of the invention to create a process and device of the above type, where the efficiency is high, i.e. the mold can be used efficiently, and where the effort is comparatively low, but always with the condition that the mould body (e.g. contact lens) produced is free of air inclusions.

This is achieved by ensuring that no air can be in the mould from the start of the filling process, thus avoiding air inclusions altogether. As a result, the mould can be closed more quickly and thus used more efficiently, at a comparatively low cost. Moreover, this also automatically provides an exact dosage of the required amount of the starting material, as the filling takes place in the starting material.

Appropriate further training of the invention is described in the dependent claims 2 to 26.

In one variant of the process, the mould cavity can be connected to a reservoir surrounding it, into which the starting material is supplied and from which the mould cavity is flooded, to fill it, a particularly low-technical process.

In another process, the mould is also closed in the starting material to avoid the risk of air entering the mould cavity by any means during the closing process.

Another variant uses a mould comprising a container and a movable mould part in that container. This mould part is moved to open and close the mould from the opposite container wall to the opposite container wall. During opening the mould, the starting material is fed between the container wall and the mould part and during closing the mould the starting material is discharged again. By moving the movable mould part away from the container opposite the mould, the space between the movable mould and the mould wall is filled with the starting material without allowing air to enter this space.

For example, a mould with two mould halves, one half on the container wall and the other half on the movable mould part, can be used; a mould with one half parent mould and one half parent mould, one half parent mould on the container wall and one half parent mould on the movable mould part, can be used; pumps can be used to pump and discharge the starting material; and a further advantageous process variant is to drive the movable mould part to pump and discharge the starting material.

The interlocking mould can be deformed in a particularly simple way by rinsing the mould with the starting material, for example by the flow of the starting material which separates the mould from the mould when the mould is opened and rinses the mould out when the mould is closed.

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However, the interlocked mould can also be removed from the mould by means of a gripper, which can be done by placing the mould removed from the mould by means of the gripper outside the space between the movable mould and the opposite wall of the container on the movable mould, holding the mould on the movable mould by applying pressure to it and then releasing it by applying pressure to it.

In another process, the mould is not completely closed after the starting material has been introduced into the mould cavity, so that a ring gap surrounding the mould cavity, connected to it, containing unmeshed starting material, remains open. This allows, on the one hand, to compensate for the volume loss resulting from the meshing by flowing starting material back into the mould cavity through the ring gap. On the other hand, it also avoids the mould halves being pressed against each other during the manufacture of the mould body. In particular, due to the risk of irreversibly deforming the mould halves under mechanical stress, the mould halves have only been used once so far, when it has been introduced.

It is also conceivable that the mould will close further as the material becomes progressively interlocked following the loss of interlocking.

In any case, it is important to use a starting material which is at least rigid and fluid before the connection, so that the starting material can flow back through the ring gap into the mould cavity to compensate for the shrinkage.

It is also possible to limit the material load by spatial confinement to the area of the mould cavity with the interconnecting energy, so that essentially only the source material in the mould cavity, i.e. the area of the mould body, especially the contact lens, is interconnected. Any excess material is not polymerized or interconnected. Sub-areas of the mould body edge are not formed by a mechanical limitation of the material by mould walls, but by a spatial limitation of the energy load (ordinary UV radiation or other radiation) that causes the polymerization or interconnection. These measures can be carried out in a mechanical manner without the need to deform the mould body in such a way that the mould cannot be easily re-assembled in the case of a mould, which is also known as the USB24A2, and can not be easily obtained in the case of a mould re-assembly.

In addition, it is possible to achieve spatial limitation of the energy charge by at least partially impenetrable masking of the form for the energy form concerned. Energy for the interconnection is radiation energy, in particular UV irradiation, gamma radiation, electron radiation or thermal radiation, preferably in the form of an essentially parallel beam of radiation, in order to achieve both a good limitation and an efficient use of energy.

It is also possible to use a form which is at least one-sidedly well permeable to the energy form which is the networking effect.

It is also possible to use a form which is well permeable to the energy form of the interconnector from at least one direction, and the spatial limitation of the energy charge is provided by a mask for energy poorly or not permeable to the energy provided on or in the form outside the form cavity.

The mask shall preferably be placed in the area of the separating planes or surfaces of different parts of the mould, in particular in areas of these parts in contact with the interconnectable source material.

Finally, it is also possible to keep the energy of the interconnection away from the source material in this ring gap, so that the interconnection can only take place in the mould cavity and in particular a backflow of source material to compensate for the volume loss is possible.

The material used is at least tough and fluid before the interlocking, so that the material can flow back through the ring gap into the mold cavity to compensate for the shrinkage.

The invention is designed to be used in a manner that prevents air from entering the mold when the mold is filled, thus avoiding air inclusions altogether. As a result, the mold can be closed more quickly and thus used more efficiently, while at the same time using relatively little effort.

Appropriate refinements of the invention in accordance with claim 27 are described in dependent claims 28 to 40.

In one embodiment, the device includes a reservoir for the provision of the starting material, which spatially surrounds the mold cavity. This reservoir is connected to the mold cavity. When filling the mold cavity, the reservoir is connected to the mold cavity and flows it. This allows several constructively particularly simple further training, which are explained in detail.

In another embodiment, the device includes means for closing the mould in the starting material, whereby the mould is always closed in the starting material so that no air can enter the mould cavity.

In an advantageous embodiment, the mould comprises a container and a movable mould part in this container, which can be moved away from and onto the opposite container wall to open and close the mould. The container has an inlet through which the starting material between the container wall and the mould part flows in during the opening of the mould. Furthermore, the container has an outlet through which the starting material flows out again during the closing of the mould. This embodiment is relatively simple in construction, so it is not very time consuming, and is therefore well suited for practical use.

The mould has two mould halves, one of which is on the container wall and the other on the movable mould part. The mould has (especially in the manufacture of contact lenses) a parent mould half and a mother mould half.

For the supply and/or removal of starting material, pumps are provided which, when the mold is opened, supply starting material between the container wall and the mould part through the inlet and, when the mold is closed, return it through the outlet.

In another example, means are provided to drive the movable mould, which can be used in a device without pumps or in a device with pumps to move the movable mould towards the opposite wall of the container, thus re-pressing the starting material between the mould halves.

In another embodiment of the device, means are used to generate a flow. This flow disengages the mould when the mould is opened and flushes it out of the mould when the mould is closed. These means can be formed as nozzles or similarly acting means.

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The moulding surface may be removed by means of a grip device which removes the interlocked moulding surface from the mould. For this purpose, the container preferably has a bulge or niche on a wall of the container different from the moulding surface, which extends essentially in the direction of the movement of the movable moulding surface. In this bulge or niche the grip device is located. The movable moulding surface has a bulge on an outer wall not opposite the moulding surface, into which the grip device deposits the moulding surface. This is a particularly convenient and simple design of the device.

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In another example of the device, the mould is provided with spacers which, when closed, keep the two mould halves close together, so that a ring gap is formed which encloses and is connected to the mould cavity.

This can compensate for the loss of volume caused by the interlocking, since the starting material can flow back into the mould cavity through the ring gap. On the other hand, it also avoids the mould halves being pressed firmly against each other during the manufacture of the mould body. In particular, because of the risk that the mould halves will deform irreversibly under mechanical stress, the mould halves have only been used once so far, as explained at the beginning.

It is also possible to provide for means which limit the energy transfer to the area of the mould cavity, so that essentially only the source material in the mould cavity, i.e. the area of the mould body, especially the contact lens, is interconnected. Any excess material is not polymerized or interconnected. Sub-areas of the mould body edge are not formed by a mechanical limitation of the material by mould walls, but by a spatial limitation of the polymerizing or interconnecting energy transfer (usually UV or other radiation). These two measures can be used in a retrofit mould to avoid contact between the two without the deformation of the mould body, which is a very simple problem, as in the case of the USB114, and can be solved without the use of a mechanical solvent.

It is also possible to provide the mould with an energy-independent or poorly permeable mask which shields from energy all mould cavities, except the mould cavity, which may contain unmeshed material or mould surfaces which may come into contact with the material.

It is also possible that the source of energy produces UV radiation and that at least one half of the form is made of a UV-permeable material, in particular quartz, the mask may consist of a layer of a non-UV-permeable material, in particular a layer of chromium, in the example of the device with the ring slit, the mask may be placed in the area of the ring slit.

Finally, in a device where the interconnection is confined to the area of the cavity of the mould, the mould may of course also be provided with elastic means or adjustment means which allow the two mould halves to be brought closer together following the loss of interconnection.

In particular, the method or device described may be used to produce moulds, in particular optical lenses and especially contact lenses.

The following illustration gives a more detailed description of the invention, showing, in part, in schematic representation or in section: Fig. 1A is an example of the device according to the invention,Fig. 2A is another example of the device according to the invention,Fig. 3A is a variant of the example of Fig. 2,Fig. 4A is another example of the device according to the invention, andFig. 5an enlarged representation of the edge area of an example of a closed-form embodiment.

The device described in Fig. 1A-C is designed for the manufacture of contact lenses from a liquid source material which can be polymerized or interlaced, e.g. by UV radiation. In Fig. 1A, the form 1 is shown in closed condition. The form 1 is placed in a container 10 filled with uninterlaced liquid source material M. The device also includes an energy source in the form of a UV light source 2a and a medium 2b which can direct the energy provided by the UV light 2a in the form of a parallel beam source 3 to the form 1. These 2a include in particular a blinding light source which can be arranged between the UV light source 2a and the medium 2a and is composed of a single UV light source 2a and the medium 2a.

Details on general construction, dimensional, material and stability issues, etc., as well as on e.g. material candidates for the moulds and process technical aspects are very extensively covered in EP-A-0.367.513 and in particular in US-A-4.113.224, and these documents are therefore explicitly declared to be an integral part of this specification (incorporation by reference).

The form 1 comprises two mould halves 11 and 12, each having a curved mould surface 13 and 14, respectively, which together define a mould cavity 15 which in turn determines the shape of the contact lens CL to be manufactured. The mould surface 13 of the upper mould half 11 is concave and determines the front surface with the adjacent edge area. Usually this mould half 11 is called the mother mould half. The mould surface 14 of the lower mould half 12 is convex and determines the back or base surface of the contact lens CL and the adjacent edge area of the same. This mould half 12 is usually called the parent mould half.

Unlike the forms known from the documents WO-87/04390 or EP-A-0.367.513 mentioned above, the mould cavity is not completely closed and dense, but in the example shown it is open all round in the area of its circumference which defines the edge of the CL lens to be manufactured. There the mould cavity 15 is also connected to a relatively narrow ring gap 16, as is the case with the moulds shown in US-A-4,113,224.The distance bolts can be adjustable (e.g. by means of a thread inserted into the parent half of the mould, not shown), they can also be spring-formed. In this way, by adjusting the spacing or against a spring force, the two moulds 11 and 12 can be moved against each other during the networking process in order to equalize the weight. The shape is of course in the usual way, e.g. by means of a closing unit indicated only by the pillar 1a, and can be opened and slid open. The equation of the distance of the two moulds for the second round comparison.B. also by means of this external locking unit.

In another embodiment not shown here, a series of segment columns may be used instead of the continuous ring slit 16 and the spacing 19 with the spaces between the individual segment columns acting as spacing.

The two halves 11 and 12 consist of a material which, as mentioned above, is as permeable as possible to the energy chosen, e.g. UV light, e.g. polypropylene or another polyolefin commonly used for such purposes. Since the irradiation with UV light is carried out here only on one side, from above, only the upper half, i.e. the mother half 11 here, needs to be UV permeable.The use of the material is not only very hard and resistant, but also very durable, so that the moulds made from this material can be reused very well. However, as the following explanations show, the condition is that the mould is either powerless or not completely closed, so that the mould halves are not damaged by contact. Alternatives to quartz are also UV-permeable special glasses or sapphires.The manufacturer's claim that the moulds are not intended to be used for the manufacture of contact lenses is based on the fact that the moulds are not intended to be used for the manufacture of contact lenses.

The space between the two mould halves 11 and 12, and therefore also the mould cavity 15, is located in the unmeshed starting material M throughout the manufacturing process. According to the general idea of the invention, at least the mould cavity is completely located in the starting material in the unmeshed state when filling. In Fig. 1B, it is seen that the upper mould half 11 does not protrude completely from the starting material M even in the open state, the space between the mould halves 11 and 12 always remains below the liquid level of the starting material in container 10.

Once the mould cavity is filled and the mould is closed (Fig. 1A), it is exposed to UV rays 3 and a networking of the mould body is achieved.

After the connection, the mould is opened and the mould body in the form of the contact lens CL is shaped, i.e. removed from the mould and removed from the mould. For this purpose, Fig. 1C symbolically provides for the grip device 4, which then, when the upper mould half is removed, removes the contact lens CL from the parent mould half 12 (Fig. 1B) and removes it from the mould (Fig. 1C). However, the moulding and removal of the contact lens or mould body from the mould can also be done in other ways, as explained in the other examples.

Since the entire manufacturing process, as shown in Fig. 1A-C, takes place below the liquid level of the starting material M in container 10, no air can enter the space between the two halves of the mould 11 and 12, and in particular into the mould cavity 15.

In the example shown in Fig. 1A-C, the UV exposure of the mould is also limited to the material in mould cavity 15, i.e. only the material in mould cavity 15 is interlaced. In particular, the starting material in the ring gap 16 surrounding mould cavity 15 and the remaining starting material in container 10 M are not energized and not interlaced.

For practical purposes, according to Fig. 1A-C, on the mould wall 17 in the area of the ring gap 16 a mask 21 is provided for the energy used, in this case UV light, impermeable (or at least poorly permeable in comparison with the permeability of the mould) which extends up to the mould cavity and, with the exception of the mould cavity, all other parts, cavities or surfaces of the mould which are or may come into contact with the liquid unmeshed material, possibly excess, which shields the irradiated material. Energy from the surface of the lens edge is prevented not by confining the material by mould walls, but by confining the polymeric or V-resolving or other mould walls, which are also surrounded by mould walls.

In the case of UV light, the mask may preferably be a thin layer of chromium which may be produced by processes such as those known as photolithography or UV lithography. Other metals or metal oxides may also be suitable as mask materials. The mask may also be coated with a protective layer, in the case of quartz as a material for the mould or moulding medium, for example from silicon dioxide. The mask need not necessarily be fixed, it may, for example, be removable or interchangeable. It could in principle be placed anywhere or in the mould provided that it fulfilled the function of covering all materials leading to the moulding, except for the moulding of the moulding, which is not necessarily a moulding machine.The mask may be placed on or just below a wall surface in contact with the unmeshed starting material, as this can largely eliminate undesirable deflection and scattering effects. This need not be the case. In principle, even a mask or masking in or on the mold may be omitted if it is otherwise possible to limit the energy load locally to the mold cavity, if necessary taking into account the optical effect of the mold. In the case of UV radiation, this could be achieved, for example, by a light source with a limited space, a suitable lens arrangement, possibly in combination with external masks, blinds or similar mountings and taking into account the optical effect of the mold.

In this example, the one half of the mold, here the parent half, is formed by a wall of a container 10a, here by the container floor 100a, so that the parent half is directly formed at the container floor 100a. In the container 10a, there is also a collapsible movable form 11a, which is designed to be moved from the opposite container, here the container floor 100a, away and back to the membrane of the container floor to the side walls of the container. In this way, the mold can be opened and closed. The volume of the container 11a could be moved on its own.

The space between the form part 11a and the floor 100a of the tank is in constant contact with a reservoir R. The pumps P1 and P2 at the inlet 101a and the outlet 102a respectively can be used to supply or discharge the material between form part 11a and the floor 100a of the tank, it being important that the space between form part 11a and the floor 100a of the tank is always filled with material M, so that no air can be completely discharged into this space. The pumps P1 and P2 are fitted with an integrated back valve, but it can also be used to integrate and discharge the material between form part 11a and the floor 100a of the tank, and a separate valve can be used between the pump and the tank.

In the case of a closed form (Fig. 2A), the form is charged with energy, here again with UV radiation 3. Here again, the charging of the form with energy from above is an example. This also causes the networking. Then the networked form body CL is removed from the form and removed from the form. First, liquid output material M is fed into the space between the container floor 100a and the form 11a by the P1 pump, the bulbous form 11a is moved upwards (Fig. 2B). The form body, in the form of the contact lens CL, can now be detached from the form and taken out of the form. This can be done by means of a special hand-held device, but this can be done more precisely as shown in Fig. 1 of the CL form.

The collapsible moulding part 11a is then moved back downwards and the material between the moulding part 11a and the container floor 100a is drained through the outlet 102a (Fig. 2C).

In principle, it is conceivable that the piston-slip moulding part 11a is driven only by the liquid source material supplied or drawn between the piston-slip part 11a and the tank floor 100a, so that the pumps P1 and P2 provide the necessary propulsion energy. It is also conceivable that no pumps are provided and that the piston-slip moulding part 11a is mechanically driven, so that the source material is absorbed during the upward movement and the source material is pushed out again during the downward movement.

The form part 11a has a 21a mask, which, as in the upper half of the form 11 in Fig. 1A-C, extends over the ring gap 16a to form cavity 15a and, if necessary, along the side walls of the collapsible form part 11a. If the mold is exposed to UV radiation 3, the networking and thus the formation of the body of the mold takes place in the area of form cavity 15a and only there. The material in the other areas, in particular in the ring gap 16a and the other starting material in the container 10a, is not already networked. The materials and the manufacture and installation of such masks are in principle the same as those described in Fig. 1A-C.

Figures 3A-C show an example of the device, which is in principle very similar to the example of Figure 2A-C. The only difference is that the example of Figure 3A-C in the output 102a does not include a P2 pump, but the output 102a is designed as a deformable tube or plate or valve. In explaining Figure 3A-C, the following will mainly deal with the shape of the mould body, in this case the contact lens CL. The filling of the mould cavity 15a is carried out by means of the pump P1 in the same way as in Figure 2A-C. The closed mould (Figure 3A) is formed by contacting the CL 3 with UV-beam.

When the piston moulding part 11a (Fig. 3B) is moved upwards, liquid source material flows into the container 10a between the container floor 100a and the piston moulding part 11a. The inlet 101a may be formed as a nozzle or similarly acting flux-producing medium. When the liquid source material is fed through the inlet, the current produced then removes the interlocked contact lens CL from the mould and, when the nozzle is arranged in the direction of the outlet 102a, flushes it out. This is then formed as a pressurized or plate-formed contact lens. When the outlet of the piston moulding part 11a (Fig. 3C) is formed as a jet or similarly acting flux-producing medium, the UV-current produced by the outlet is absorbed by the flow. The liquid is then released for further contact with the source material 102a, and can be freely re-filled with a new contact material CL 102a. The outlet may be filled with a liquid liquid after contact with the source material has been made, for example, by means of a new contact lens.

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Another embodiment of the device is shown in Fig. 4A-C. This embodiment is in principle similar to the embodiments described in Fig. 2A-C and Fig. 3A-C, but differs significantly from them in that it includes a slightly differently formed column-shaped movable form part 11b. Furthermore, the container 10b is also significantly shaped in that it has a bulge or niche 104b on one side of it, 103b, which extends in the direction of the pressure movement of the piston on the other side of the form part 11b. In the source source N of this 104b, the sub-form part 11b is a grip 4b, which is located in the direction of the column 11b. The 11b is positioned in the direction of the column 113, which is also a sub-form part 114b, and the 113, which is located in the direction of the column 113, which is also a channel 114b, which is located in the direction of the column 113.

The manufacture of the CL contact lens by cross-linking by applying UV radiation to the mould 3 is done again in the same way as described in Fig. 2A-C and Fig. 3A-C. The explanation of Fig. 4A-C will therefore focus primarily on the way in which the CL contact lens is deformed. In the closed form, the mould is re-imposed with UV radiation 3 and the CL contact lens is produced by cross-linking (Fig. 4A). Then the P1 pump pump pump pumps the source material between the mould 11b and the mould 100b bottom and the mould 11b bottom is pumped back up again (Fig. 4B). The mould source is moved back upwards through the mould 11b bottom (Fig. 4B). The mould 4B is now moved in the direction of the mould 104 N. The mould is then moved in the direction of the mould 104 N. The mould is then removed in the direction of its contact material, so that the mould is pulled back upwards through the mould 11b bottom and the mould 11b bottom is pulled back upwards (Fig. 4B). The mould is then moved in the direction of the mould 104 N. The mould is then pulled out in the direction of its contact material (Fig. 4B, 104 N. 104 P, 104 P, 104 P, and 104 P) so that the mould is pulled back in the direction of its contact material and the mould is then pulled back out in the direction of the mould 110 N.

The gripper 4b, located in slot 104b, is either sliding along the outer face of the form 11b 113b or is held in slot 104b until the gripper 40b is on the outer face of the form 11b 114b. At this point, the pressure is applied through the hole in the gripper 40b so that the contact lens CL is detached from the gripper 40b and deposited in the form 114b. Through the channel 114b leading to the gripper, the pressure is applied at the same time as the contact lens CL is removed from the gripper 40b, i.e. the pressure is applied so that the contact lens CL 40b is simply removed from the gripper 40b and deposited in the form 114b (Fig.A.4).

When the form 11b has been moved upwards, the notch 114b of form 11b is located outside the container 10b (Fig. 4B). If overpressure is then applied through the channel 115b, the contact lens CL will detach from the notch 114b and can be fed into further processing. In particular, it should be noted that the sidewall 103b can extend further upwards and have a further niche into which the contact lens CL can be deposited or flushed, thus achieving even better guidance of form 11b and a smoothness of its corresponding dense surfaces sliding along the container wall.

For the application of overpressure or underpressure, the P3 pump is shown in Fig. 4A-C, with the overpressure connection HP or the underpressure connection NP connected to the channel 115b or to the hole in the gripper plate 40b, depending on the position of the column-shaped movable part. This P3 pump can draw from the reservoir R in which the starting material is supplied, starting material to generate the required pressure. In Fig. 4A-C, at the input 101b and at the input 102b, two separate reservoirs are shown, into which the P1 or P2 and P3 pumps are fed, but it is obvious that it is also possible that this is a single reservoir.

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As already discussed in the explanation of the individual figures, when the mould halves are closed, excess starting material is displaced into the ring gap 16 between the two mould halves. The ring gap 16 which is better recognized in Fig. 5 is selected so far or so high (Δy) that a contact of the two mould halves 11 and 12 (or a contact of the mould part 11,11a,11b with the container floor 100,100a,100b) is safely and reliably avoided in the area of the mask 21.

The shape of the cavity 15 in Fig. 5 is an example of a shape corresponding to the typical edge geometry of a so-called soft contact lens. The cavity and thus the contact lens edge are formed by two wall surfaces 22 and 23 at right angles to each other, formed at the male 12 and female shapes respectively.

As can be clearly seen, the wall surface 23 of the mould half 11 does not reach quite up to and the wall surface 22 but is about Δy of the ring slit 16 lower. Typical gap heights Δy are for the manufacture of contact lenses in the range below about 100 μm. Experiments have shown that at least when using parallel energy radiation a clean edge structuring of the mould body produced is still possible even at gap heights of about 1 mm. Conversely, however, it is also possible without further ado to reduce the width or height of the slit to virtually zero if the mould is closed only by force, so that the mould halves lie on top of each other without further strain.

However, even if the mould is closed with force and is used only once, the device of the invention is still distinguished from known devices by the fact that the mould is closed in the starting material and can thus be closed more quickly without the risk of air inclusions.

In the case of unilateral energy storage, the moulded half-forms which are not connected to the energy source can in principle be made of any material compatible with the interconnecting or interconnected material or components thereof. However, if metals are used, potential reflections can be expected, depending on the type of energy radiation, which may lead to undesirable effects such as overexposure, edge distortion or the like.

In principle, it is also possible to use deflection and/or scattering effects of the radiation affecting the mould to produce a deliberately blurred contour or slightly rounded edge of the mould to be manufactured. The same effect can also be achieved with masks with locally variable permeability. Sharp edges of the mould can thus be rounded off by targeted incomplete networking and by triggering the incompletely networked areas with a suitable solvent, which may also be the unlinked starting material itself. In the case of HEMA (hydroxyethyl methalate) as starting material, for example, isopropanol is a suitable solution.

It is also clear that the device described in the figures can also contain several cavities instead of just one, so that several contact lenses can be produced simultaneously during a cycle. In addition, the piston-moulded variants can be specifically controlled in such a way that the piston-moulded part is first mechanically loaded and the starting material is released into the container with a slight delay during the supply or released out of the container with a slight delay during the discharge. This also applies to the variant that uses both pumps and the piston is mechanically driven.

A variant is also possible in which the number of cycles after which a new contact lens is produced is variable. For example, a sensor can detect whether a contact lens has actually been rinsed out of the mould and only when the sensor has detected such a rinsed out contact lens, the mould is completely closed and a new contact lens is produced. If the sensor does not detect a rinsed out contact lens, the mould is further rinsed until the contact lens has been rinsed out of the mould.

For the contact lens CL can be used as a starting material that can be interconnected with UV light by irradiation, for example the HEMA (hydroxyethyl methacrylate) or poly-HEMA, which is widely used for these purposes, especially in combination with a suitable connector such as ethylene glycol dimethylacrylate. For other moulds, other materials may be used depending on the purpose of use, although other forms of energy, e.g. electron radiation, gamma radiation, thermal energy, etc., are generally possible to trigger the interconnection depending on the type of material to be interconnected. However, in the manufacture of contact lenses, interconnecting materials under UV light are generally not mandatory.

The starting materials are particularly special prepolymers, in particular those based on polyvinyl alcohol containing cyclic acetal groups and interconnectable groups.

Contact lenses based on polyvinyl alcohol are already known, e.g. EP 216.074 reveals contact lenses containing polyvinyl alcohol with (meth) acryloyl groups bound via urethane groups, EP 189.375 describes contact lenses made of polyvinyl alcohol cross-linked with polyepoxides.

In addition, some special acetals are already known to contain interconnectable groups. In this context, for example, reference is made to EP 201,693, EP 215,245 and EP 211,432. EP 201,693 describes, among other things, acetals of unbranched aldehydes with 2 to 11 carbon atoms, which finally carry an amino group, whose amino group is replaced by a C3-C24 olefin-unsaturated organic radical. This organic radical has a functionality that removes nitrogen electrons, and the function described is polymerized by the olefin-unsaturated function. In EP 201, polyvinyl chloride 1,2-diol, 1,3-diol, or a product of the non-alcohol cell is also characterized by the reaction products of the acetylated 1,2-diol.

If one of the acetals in EP 201.693 is mentioned at all in connection with, for example, polyvinyl alcohol, as is the case, inter alia, in example 17 of that patent application, the acetal which is polymerizable by its olefin group is first copolymerized with, for example, vinyl acetate.

In contrast, according to one aspect of the present invention, the prepolymers contain a 1,3-diol scaffold, whereby a certain percentage of the 1,3-diol units are modified to a 1,3-dioxane having a polymerizable but non-polymerizable residue at the 2-position.

The prepolymer used is preferably a derivative of polyvinyl alcohol with a molecular weight of at least approximately 2000 and containing between approximately 0,5 and approximately 80% of units of formula I, depending on the number of hydroxyl groups in the polyvinyl alcohol, where R is for niederalkylenes up to 8 carbon atoms, R1 is for hydrogen or niederalkyl and R2 is an olefin unsaturated, electron-expressed, copolymerizable residue preferably up to 25 carbon atoms.

For example, R2 is an olefin unsaturated acyl residue of the formula R3-CO-, where R3 is an olefin unsaturated copolymerizable residue of 2 to 24 carbon atoms, preferably 2 to 8 carbon atoms, especially preferably 2 to 4 carbon atoms. Other The following substances are to be classified as "methanol" and "petroleum": Other where q is zero or one and R4 and R5 are independently defined as niederalkylenes with 2 to 8 carbon atoms, arylenes with 6 to 12 carbon atoms, a saturated bivalent cycloaliphatic group with 6 to 10 carbon atoms, arylenes or alkylenes with 7 to 14 carbon atoms or arylenes with 13 to 16 carbon atoms, and where R3 has the meaning given above.

The prepolymer is therefore in particular a derivative of polyvinyl alcohol with a molecular weight of at least approximately 2000 containing units of formula III ranging from approximately 0,5 to approximately 80%, depending on the number of hydroxyl groups in the polyvinyl alcohol, where R stands for niederalkyl, R1 for hydrogen or niederalkyl, p has a value of zero or one, q has a value of zero or one, R3 means an olefin unsaturated copolymerizable residue with 2 to 8 carbon atoms and R4 and R5 independently mean niederalkyl with 2 to 8 carbon atoms, arylic 6 with 12 to 16 carbon atoms, a saturated bivalent cycloalkyl group with 6 to 10 carbon atoms, arylic or alkyl aryl aryl aryl aryl aryl aryl or 14 to 16 carbon atoms.

Niederkylene R preferably has up to 8 carbon atoms and can be straight or branched. Suitable examples include octylene, hexylene, pentylene, butylene, propylene, ethylene, methylene, 2-propylene, 2-butylene or 3-pentylene. Niederkylene R preferably has up to 6 and preferably up to 4 carbon atoms.

R1 means preferably hydrogen or a nioderalkyl with up to seven, in particular up to four carbon atoms, in particular hydrogen.

Niederkylene R4 or R5 preferably has 2 to 6 carbon atoms and is particularly straight chain.

Arylene R4 or R5 is preferably a phenylene that is unsubstituted or substituted by a niederalkyl or niederalcoxy, in particular 1,3-phenyl or 1,4-phenyl or methyl-1,4-phenyl.

A saturated bivalent cycloaliphatic group R4 or R5 is preferably cyclohexyls or cyclohexyl-niederalkyls, e.g. cyclohexylenmethyls, which are unsubstituted or replaced by one or more methyl groups, e.g. trimethylcyclohexylenmethyls, e.g. the bivalent isophoron residue.

The arylene unit of an alkyl arylene or arylene alkyl R4 or R5 is preferably a phenylenes, unsubstituted or substituted by a niederalkyl or niederalcoxy, the alkyl unit of which is preferably a niederalkyl such as a methylene or ethylene, especially a methylene.

Aryl alkyl aryl R4 or R5 is preferably a phenylen-niederkyl phenylen with up to 4 carbon atoms in the alkyl unit, e.g. phenylenethylene phenylenes.

The residues R4 and R5 shall be preferably, independently of each other, niederalkylenes with 2 to 6 carbon atoms, phenylenes unsubstituted or substituted by niederalkyl, cyclohexylenes or cyclohexylene-niederalkylenes unsubstituted or substituted by niederalkyl, phenylenes-niederalkylenes, niederalkylenes-phenylenes or phenylenes-niederalkylenes.

Err1:Expecting ',' delimiter: line 1 column 55 (char 54)

Niederalkyl has in particular up to 7 carbon atoms, preferably up to 4 carbon atoms, and is e.g. methyl, ethyl, propyl, butyl or tert-butyl.

Niederkoxy in particular has up to 7 carbon atoms, preferably up to 4 carbon atoms, and is e.g. methoxy, ethoxy, propoxy, butoxy or tert-butoxy.

The olefin unsaturated copolymerizable residue R3 with 2 to 24 carbon atoms preferably means alkenyl with 2 to 24 carbon atoms, in particular alkenyl with 2 to 8 carbon atoms and especially alkenyl with 2 to 4 carbon atoms, such as ethenyl, 2-propenyl, 3-propenyl, 2-butenyl, hexenyl, octenyl or dodecenyl. The meanings ethenyl and 2-propenyl are preferred, so that the -CO-R3 group represents the acyl residue of acrylic acid or metal acrylic acid.

The bivalent group -R4-NH-CO-O- is present when q is one and absent when q is zero.

The bivalent group -CO-NH-(R4-NH-CO-O) q-R5-O- is present when p is one and absent when p is zero.

In prepolymers where p is one, the index q is preferably zero. In particular prepolymers where p is one, the index q is zero and R5 is niederalkyls are preferred.

A preferred prepolymer is therefore in particular a derivative of polyvinyl alcohol with a molecular weight of at least approximately 2000 containing units of formula III ranging from approximately 0,5 to approximately 80%, depending on the number of hydroxyl groups in the polyvinyl alcohol, where R stands for niederalkyls with up to 6 carbon atoms, p for zero and R3 for alkenyl with 2 to 8 carbon atoms.

Another preferred prepolymer is therefore in particular a derivative of polyvinyl alcohol with a molecular weight of at least about 2000 containing units of formula III ranging from about 0,5 to about 80%, depending on the number of hydroxyl groups in the polyvinyl alcohol, where R stands for niederalkylenes with up to 6 carbon atoms, p stands for one, q stands for zero, R5 stands for niederalkylenes with 2 to 6 carbon atoms and R3 stands for alkenylenes with 2 to 8 carbon atoms.

Another preferred prepolymer is therefore in particular a derivative of polyvinyl alcohol with a molecular weight of at least 2000 and containing units of formula III ranging from about 0,5 to about 80%, depending on the number of hydroxyl groups in the polyvinyl alcohol, where R stands for niederalkylenes with up to 6 carbon atoms, p one, q one, R 4 for niederalkylenes with 2 to 6 carbon atoms, phenylenes unsubstituted or substituted by niederalkyl, cyclohexylenes or cyclohexy-niederalkylenes unsubstituted or substituted by niederalkyl, phenylenes with 2 to 8 carbon, phenylenes with 2 to 8 carbon, and R 5 for niederalkylenes with 6 to 8 carbon.

The prepolymers are derivatives of polyvinyl alcohol with a molecular weight of at least about 2000 which contains between about 0,5 and about 80% units of formula III, in particular between 1 and 50%, preferably between 1 and 25%, preferably between 2 and 15% and preferably between 3 and 10%. Prepolymers intended for the manufacture of contact lenses contain between 0,5 and about 25% units of formula III, in particular between 1 and 15%, and preferably between 2 and about 12%.

Polyvinyl alcohols which can be derived preferably have a molecular weight of at least 10000. As a maximum, polyvinyl alcohols may have a molecular weight of up to 1000000. Polyvinyl alcohols preferably have a molecular weight of up to 300000, in particular up to about 100000, and preferably up to about 50000.

Normally, suitable polyvinyl alcohols have mainly a poly (((2-hydroxy) ethylene structure. However, the derived polyvinyl alcohols may also have hydroxy groups in the form of 1,2-glycols, such as copolymer units of 1,2-dihydroxyethylene, such as those obtained by alkaline hydrolysis of vinyl acetate-vinyl carbonate copolymers.

In addition, the derived polyvinyl alcohols may also contain small amounts, for example up to 20%, preferably up to 5%, of copolymer units of ethylene, propylene, acrylamide, methacrylamide, dimethacrylamide, hydroxyethyl methacrylate, methyl methacrylate, methylacrylate, ethylacrylate, vinylpyrrolidone, hydroxyethylacrylate, allyl alcohol, styrene or similar commonly used monomers.

Commercial polyvinyl alcohols can be used, such as Vinol® 107 by Air Products (MW = 22000 to 31000, 98 to 98,8% hydrolysed), Polysciences 4397 (MW = 25000, 98,5% hydrolysed), BF 14 by Chan Chun, Elvanol® 90 to 50 by DuPont, UF-120 by Unitika, Moviol® 4-88, 10-98 and 20-98 by Hoechst. Other manufacturers include Nippon Gelohsei (Gohsenol®), Monsanto (vatol®), Wacker (Polyviol®) or the Japanese manufacturers Kuraray, Denki and Shin-Etsu.

As mentioned above, copolymers of hydrolysed vinyl acetate, available for example as hydrolysed ethylene vinyl acetate (EVA) or vinyl chloride vinyl acetate, N-vinylpyrrolidone vinyl acetate and maleic anhydride vinyl acetate, can also be used.

Polyvinyl alcohol is usually produced by hydrolysis of the corresponding homopolymer polyvinyl acetate. In a preferred embodiment, the derived polyvinyl alcohol contains less than 50% polyvinyl acetate units, in particular less than 20% polyvinyl acetate units.

The compounds containing units of formula III can be produced in a known way. For example, a polyvinyl alcohol with a molecular weight of at least about 2000 containing units of formula IV can be produced in a known way. Other - CH ((OH) - CH2- (IV) Other with a content of approximately 0,5% to 80%, by weight, of the compound of formula (V), where R' and R' are independently hydrogen, niederalkyl or niederalkanoyl such as acetyl or propionyl and the other variables have the values given for formula III, in particular in acidic medium.

Alternatively, a polyvinyl alcohol of a molecular weight of at least approximately 2000 containing units of formula IV may be converted into a formula VI compound, in which the variables are defined as for the formula V compound, in particular under acidic conditions, and the cyclic acetal thus obtained may then be converted into a formula VII compound. Other The following substances are to be classified in the same category as the active substance: Other where the variables are defined as for the formula V compound.

Alternatively, the reaction product obtained from a compound of formula IV and a compound of formula VI as described above may be obtained from a compound of formula (VIII) Other The following shall be added to the list of substances: Other where R3 is for alkenyl with 2 to 8 carbon atoms and X is for a reactive group, e.g. for etherised or esterified hydroxy, e.g. for halogens, especially for chlorine.

For example, formula V compounds where p stands for zero are known from EP 201,693. Compounds of formula VI are also described there. Compounds of formula VII are known in themselves or can be produced in a known way. An example of a formula VII compound where q stands for zero is isocyanatoethylmethacrylate. An example of a formula VII compound where q stands for one is the reaction product of isophorisocyanate with 0.5 aequivalent hydroxyethyl methalate.

The prepolymers of formula I and III are surprisingly stable, which is unexpected for the professional because, for example, higher functional acrylates usually need to be stabilized. If such compounds are not stabilized, rapid polymerization usually occurs. However, spontaneous cross-linking by homopolymerization does not take place with the prepolymers. The prepolymers of formula I and III can also be purified in known ways, for example by acetone, dialysis or ultrafiltration, where ultrafiltration is particularly necessary.

The preferred purification method of the prepolymers, an ultrafiltration, can be performed in a known way. There is the possibility of performing the ultrafiltration repeatedly, for example, two to ten times. Alternatively, the ultrafiltration can also be performed continuously until the desired degree of purity is reached. The desired degree of purity can be chosen in principle at any appropriate level.

The prepolymers of formula I and III, on the other hand, are highly efficient and can be specifically interlinked, in particular by photointerlinking.

In the case of photo-interlacing, a photoinitiator is added which can initiate a radical interlacing. Examples of this are familiar to the professional, in particular suitable photoinitiators can be benzoin methyl ether, 1-hydroxycyclohexylphenyl ketone, Daracure 1173 or Irgacure types.

Photopolymerization is best done in a solvent. In principle, any solvent that dissolves polyvinyl alcohol and any additional vinyl comonomers used is suitable as a solvent, e.g. water, alcohols such as low-alcohols, e.g. ethanol or methanol, and carbonic amides such as dimethylformamide or dimethyl sulfoxide, as well as mixtures of suitable solvents, e.g. mixtures of water with an alcohol, e.g. a water/ethanol or water/methanol mixture.

The photoresist is preferably obtained directly from an aqueous solution of the prepolymers which can be obtained as a result of the preferred purification step, ultrafiltration, if necessary with the addition of an additional vinyl monomer.

The process of manufacturing the polymers may be characterised, for example, by photophotography of a prepolymer containing units of formula I or III, in particular in essentially pure form, i.e. for example after one or more ultrafiltrations, preferably in solution, in particular in aqueous solution, in the absence or presence of an additional vinyl comonomer.

The vinyl comonomer, which may be used in addition to the photoresist according to the invention, may be hydrophilic, hydrophobic or a mixture of a hydrophobic and a hydrophilic vinyl monomer. Suitable vinyl monomers include, in particular, those commonly used in the manufacture of contact lenses. A hydrophilic vinyl monomer is a monomer that typically produces a polymer that is water-soluble or can absorb at least 10% by weight as a homopolymer. Analogically, a hydrophobic vinyl monomer is a monomer that typically produces a polymer that is insoluble in water and can absorb less than 10% by weight of water as a homopolymer.

Generally, between about 0.01 and 80 units of a typical vinyl comonomer react per unit of formula I or III respectively.

If a vinyl comonomer is used, the cross-linked polymers preferably contain between about 1 and 15%, and particularly preferably between about 3 and 8%, units of formula I or III respectively, based on the number of hydroxyl groups of the polyvinyl alcohol translated with about 0,1 to 80 units of the vinyl monomer.

The proportion of vinyl comonomers, if used, shall preferably be between 0,5 and 80 units per unit of formula I, in particular between 1 and 30 units of vinyl comonomer per unit of formula I and, in particular, between 5 and 20 units per unit of formula I.

It is also preferable to use a hydrophobic vinyl comonomer or a mixture of a hydrophobic vinyl comonomer with a hydrophilic vinyl comonomer, containing at least 50% by weight of a hydrophobic vinyl comonomer, which will improve the mechanical properties of the polymer without significantly reducing the water content. However, in principle, both conventional hydrophobic vinyl comonomers and conventional hydrophilic vinyl comonomers are suitable for copolymerization with polyalcohol containing groups of forvinyl I.

Suitable hydrophobic vinyl compounds include, without being exhaustive, C1-C18 alkylacrylates and methacrylates, C3-C18 alkylacrylamides and methacrylamides, acrylonitrile, methacrylnitrile, vinyl-C1-C18 alkanoates, C2-C18 alkenes, C2-C18 halogenates, styrene, C1-C6-alkylstyrol, vinyl-acrylate containing from 1 to 6 carbon atoms in the alkyl group, C2-C10 perfluoroalkylacrylate and methacrylate or corresponding partial fluoroalkylacrylate and methacrylate, C3-C12 perfluoroalkylacrylamide, C1-C18 alkycylconsacylcarbonyl-acrylate, C1-C18 alkycylconsacylcarbonyl-acrylate, C1-C12 alkycylconsacylcarbonyl-acrylate, C1-C12 alkycylconsacylcarbonyl-acrylate, C1-C1-C12 alkycylconsacylconsacylcarbonyl-acrylate, C1-C1-C1-C1-C1-C1-C1-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C4-C

Examples of suitable hydrophobic vinyl compounds include methyl acrylate, ethyl acrylate, propylacrylate, isopropylacrylate, cyclohexylacrylate, 2-ethyl hexylacrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, vinyl acetate, vinyl propionate, vinyl buryrate, vinyl valerate, styrene, chloroprene, vinyl chloride, vinyl chloride, acrylonitrile, 1-butane, butadiene, methacritrile, vinyl nitrile, vinyl toluene, vinyl ethyl ether, perfluorethyl methacrylate, methacrylonitrile, bispropyl ether, methacrylonitrile, methacrylonitrile, methacrylonitrile, methacrylonitrile, methacrylonitrile, methacrylonitrile, methacrylonitrile, methacrylonitrile, methacrylonitrile, methacrylonitrile, methacrylonitrile, methacrylonitrile, methacrylonitrile, methacrylonitrile, methacrylonitrile, methacrylonitrile, methacrylonitrile, methacrylonitrile, methacrylonitrile, methacrylonitrile, methacrylonitrile, methacrylonitrile, methacrylonitrile, methylonitrile, methylonitrile, methylonitrile, methylonitrile, methylonitrile, methylonitrile, methylonitrile, methylonitrile, methylonitrile, methylonitrile, methylonitrile, methylonitrile, methylonitrile, methylonitrile, methylonitrile, methylon, methylon, and 3-methacrylonitrile.

Err1:Expecting ',' delimiter: line 1 column 657 (char 656)

Examples of suitable hydrophilic vinyl comonomers include hydroxyethyl methacrylate, hydroxyethyl methacrylate, acrylamide, methacrylamide, dimethylacrylamide, allyl alcohol, vinyl pyridine, vinyl pyrrolidone, glycerin methacrylate, N- (1,1-dimethyl-3-oxobutyl) acrylamide, and the like.

The preferred hydrophobic vinyl comonomers are methyl methacrylate and vinyl acetate.

The preferred hydrophilic vinyl comonomers are 2-hydroxyethyl methacrylate, N-vinylpyrrolidone and acrylamide.

The following examples, unless expressly stated otherwise, are quantity data, weight data, temperatures are given in degrees Celsius.

Example 1a): 105.14 parts aminoacetaldehyde dimethylacetal and 101.2 parts triethylamine in 200 parts dichloromethane are dripped under ice 104.5 parts methacrylochloroid dissolved in 105 parts dichloromethane at maximum 15°C for 4 hours. After completion of the reaction, the dichloromethane phase is washed with 200 parts water, then with 200 parts 1N HCl solution, then twice with 200 parts water. Drying with anhydrous magnesium sulphate, the dichloromethane phase is evaporated and stabilized with 0.1% relative to the reaction product, 2,6-diethylbutyl-cryptopyrrole. At 90°C mbar-10-3 mbar-10 at 90°C mbar-3 mbar-10 at 112°C mbar-10 mbar, glamethyl dimethylamide is obtained as dimethyl sulphate liquid (dimethyl sulphate) with a colour of 112%.

Example 1b): 52,6 g aminoacetaldehyde dimethylacetal are dissolved in 150 ml of deionised water and cooled to 5 °C under freezing conditions. Then 50 ml of methacrylic acid chloride and 50 ml of 30% sodium bromide are added simultaneously for 40 minutes so that the pH is maintained at 10 and the temperature does not rise above 20 °C. After completion of addition, the residual content of aminoacetaldehyde dimethylacetal is determined by gas chromatography to 0,18% by means of hydroxyde dihydroacetaldehyde. Further addition of 2,2 ml of methacrylic acid chloride and 2,0 ml of 30% sodium bromide is made by completely surrounding the phase. The solution is then mixed with 1 Nitrogen (H2O) nitrate (H2O) nitrate = 7 g/m2. The product is mixed with water and water of 0.8 g/m2 of methacrylic acid and 0.8 g/m2 of petroxydehydroacetaldehyde. The product is mixed with water and water. The product contains 0.8 g/m2 of petroxydehydroacetaldehyde.

Example 2: 10 parts of polyvinyl alcohol with a molecular weight of 22'000 and a solubility of 97.5 - 99.5% are dissolved in 90 parts of water, 2.5 parts of methacrylamidoacetaldehyde-dimethylacetal are added and acidified with 10 parts of concentrated hydrochloric acid. The solution is stabilized with 0.02 parts of 2,6-di-tert-butyl-p-cresol. After 20 hours of stirring at room temperature, the solution is set to 7 with a 10% sodium salt solution and then ultrafiltered seven times over a 3k membrane (ratio 1:3).

Example 3: 10 Parts of the solution of methacrylamidoacetaldehyde-1,3-acetals of polyvinyl alcohol obtained in Example 2 are photochemically cross-linked by replacing them with 0,034 parts of Darocure 1173 (CIBA-GEIGY). This mixture is exposed as a 100 micron layer between two glass plates with 200 pulses of a 5000 watt exposure device from the company Dust.

Example 4: 110 g of polyvinyl alcohol (Moviol 4-88, Hoechst) are dissolved in 440 g of deionised water at 90 °C and cooled to 22 °C. 100,15 g of a 20.6% aqueous solution of methacrylamidoacetaldehyde-dimethyl acetal, 38,5 g of concentrated hydrochloric acid (37% p.a., Merck) and 44,7 g of deionised water are added. The mixture is stirred at room temperature for 22 hours and then set to pH = 7,0 with a 5% NaOH solution. The solution is diluted with deionised water to 3 litres of air, filtered and reduced by a 1-KD omega membrane of the company Ultravinyl Polyvinyl acetate. After three filters have been injected into the polymer, the solution is concentrated in a 0,96% solution of man-made acetic acid. The solution is concentrated in a 0,96% solution of methacrylamidoacetaldehyde and contains a total of 11,9-9% of the acetic acid and a molecular weight of 10,9-9% of the polymer.

Example 5: 133.3 g of a 15% polyvinyl alcohol solution (Moviol 4-88, Hoechst) is mixed with 66.6 g of deionized water, 3.3 g of monomeric 4-methacrylamidobutyraldehydeethylacetal and 20.0 g of concentrated hydrochloric acid (37% by weight, Merck) and stirred at room temperature for 8 hours. The solution is then set to pH = 7 with 5% sodium hyaluronic acid. After ultrafiltration of this solution via a 3 KD omega membrane from Filtron, reducing the sodium chloride content of the polymer solution from 2.07% to 0.04%, a 20 g solution of polyvinyl acetyl polyvinyl group of the methacrylamide-1,3-hydroxydeethylamideethylamide group is obtained. The groups are composed of 0,41%, 0.3%, and 0.4% of the polymer group are covered with a 7.5 μm thickness of acetic acid.

Example 6: 200 g of a 10% polyvinyl alcohol solution (Moviol 4-88, Hoechst) are mixed with 2.4 g (14.8 mmol) aminobutyraldehyde diethyl acetal (Fluka) and 20 g of concentrated hydrochloric acid (37% p.a., Merck). The solution is stirred at room temperature for 48 hours and then neutralized with 10% sodium salts. The solution is diluted to 400 ml. 200 ml of this solution are further processed as in Example 7. The remaining 200 ml of this solution are mixed with 0.85 g (8.1 mmol) methacryl chloride (Fluka) and the pH is maintained at 2 N sodium salts at pH = 10-59. At room temperature the polymer is maintained at pH 7.0 for 30 minutes. The 3-D-methacryl chloride solution is purified with a pH of 27.6%. The pH of the polymer is maintained at room temperature at pH 0.05.

Example 7: 200 ml of the polymer solution of example 6 is mixed with 1.3 g (8.5 mmol) 2-isocyanatoethylmethacrylate and the pH is maintained at 10 with 2N sodium chloride solution. After 15 minutes at room temperature, the solution is neutralized with 2N hydrochloric acid and ultrafiltered analogously as in example 6. After concentrating, a 27.1% polymer solution of 4-methacryloylethyl ureido) butyraldehyde-1,3-acetals of polyvinyl alcohol with a viscosity of 2320 cp is obtained. The inherent viscosity of the polymer is 0.390. The nitrogen content is 1.9%.

Example 8: The 30.8% polymer solution of example 4 with a viscosity of about 3600 cp is mixed with 0.7% Darocur 1173 (relative to the polymer content). The solution is filled into a transparent polypropylene contact lens mould, the mould is closed. The solution is exposed to light for 6 seconds from a distance of 18 cm by means of a 200-watt Oriel UV lamp. The mould is opened and the finished contact lens can be removed. The contact lens is transparent and has a water content of 61%. The modulus is 0.9% mPa, the refractive index 50%. The contact lens is autoclaved at 121 °C for 40 minutes. No changes in contact lens mould can be detected.

Example 9: 10.00 g of a 27.1% polymer solution as shown in example 7 is mixed with 0.0268 g of darocur 1173 (0.7% relative to polymer content) and 0.922 g of methyl methacrylate. After adding 2.3 g of methanol, a clear solution is obtained. This solution is exposed to light for 14 seconds by a 200-watt Oriel lamp, as in example 8.

Example 10: 12.82 g of a 24.16% solution of the prepolymer from example 4 are mixed with 1.04 g acrylamide and 0.03 g darocur 1173. The clear solution is then exposed to the light of example 8 by a 200 W oriel lamp for 14 seconds.

The polymers can be processed into moulds in a known way, in particular into contact lenses, for example by photo-interlacing the prepolymers of the invention into contact lens moulds in the manner described in detail above. Other examples of moulds of the invention, in addition to contact lenses, are biomedical or special ophthalmic moulds, e.g. intraocular lenses, eye patches, moulds that can be used in surgery, such as heart valves, artificial arteries or the like, and films or membranes, e.g. membranes for diffusion control, photoresist or photoresist or photoresist materials for information storage.

Contact lenses incorporating, or consisting essentially or wholly of, a polymer as described above have a range of unusual and extremely advantageous properties, including excellent compatibility with the human cornea, based on a balanced ratio of water content, oxygen permeability and mechanical properties. Furthermore, the contact lenses of the invention are of high resistance to moulding.

It can also be emphasized that such contact lenses, as described, can be manufactured in a very simple and efficient way compared to the state of the art. This is due to several factors. Firstly, the starting materials are inexpensive to obtain or manufacture. Secondly, the advantage is that the prepolymers are surprisingly stable, so that they can be subjected to a high-grade cleaning.

All the above advantages are naturally applicable not only to contact lenses but also to other moulds.The sum of the various advantages in the manufacture of moulds makes moulds particularly suitable as mass-produced articles, such as contact lenses, which are worn for a short period of time and then replaced by new lenses.

Claims (40)

1. A process for the manufacture of mouldings (CL), especially optical lenses, specifically contact lenses, from a starting material (M) that is crosslinkable by the impingement of suitable energy (3), in a mould (1) that is at least partially permeable to the energy concerned and that has a mould cavity (15) determining the shape of the moulding (CL) to be produced, the starting material (M) being introduced into the mould (1) in a still at least partially uncrosslinked state, and being crosslinked in that mould, to a degree sufficient for it to be possible for the moulding to be released from the mould, by impingement of the energy (3) concerned, wherein the filling of the mould cavity (15) is carried out in the starting material (M) that is still at least partially in the uncrosslinked state.
2. A process according to claim 1, wherein for filling the mould cavity (15) the cavity is connected to a reservoir (R) which surrounds it, in which the starting material is stored and from which the mould cavity (15) is flooded.
3. A process according to either claim 1 or claim 2, wherein the mould (1) is closed in the starting material.
4. A process according to claim 1, wherein a mould is used that comprises a container (10a, 10b) and a mould member (11a, 11b) that is displaceable in that container and can be moved away from and towards the container wall (100a, 100b) lying opposite it for the purpose of opening and closing the mould, starting material being fed in between the container wall (100a, 100b) and the mould member (11a, 11b) as the mould is opened and conveyed away again as the mould is closed.
5. A process according to claim 4, wherein a mould (1) having two mould halves is used in which one mould half is provided on the container wall (100a, 100b) and the other mould half is provided on the displaceable mould member (11a, 11b).
6. A process according to claim 5, wherein a mould having a male mould half and a female mould half is used, the male mould half being provided on the container wall (100a, 100b) and the female mould half being provided on the displaceable mould member (11a, 11b).
7. A process according to any one of claims 4 to 6, wherein pumps (P1, P2) are used to feed in and convey away the starting material.
8. A process according to any one of claims 4 to 6, wherein the displaceable mould member (11a, 11b) is driven in order to feed in and convey away the starting material.
9. A process according to any one of claims 1 to 8, wherein the crosslinked moulding (CL) is released from the mould by flushing out the mould with starting material.
10. A process according to any one of claims 4 to 8 and according to claim 9, wherein the moulding (CL) is separated from the mould by the flow of starting material as the mould is opened and is flushed out of the mould by the flow of starting material as the mould is closed.
11. A process according to claim 9, wherein in a first cycle the mould is opened and closed again, then at least the crosslinking necessary for it to be possible for the moulding (CL) to be released from the mould is effected by the impingement of energy (3) and, in a second cycle, the mould is opened again, the moulding being separated from the mould and the mould member (11a) then being moved back towards the opposite-lying container wall (100a) again in order to close the mould, in the course of which the crosslinked moulding is flushed out of the mould.
12. A process according to any one of claims 1 to 8, wherein the crosslinked moulding is removed from the mould by means of a gripping device (4).
13. A process according to any one of claims 4 to 8 and according to claim 12, wherein the moulding (CL) removed from the mould by the gripping device (4, 4b) is deposited on the displaceable mould member (11b) outside the space between the displaceable mould member (11b) and the opposite-lying container wall (100b).
14. A process according to claim 13, wherein the moulding deposited on the displaceable mould member is held fast thereto by negative pressure (NP) and then released from it by positive pressure (HP).
15. A process according to any one of claims 1 to 14, wherein the mould is not fully closed after the introduction of the starting material into the mould cavity, so that an annular gap (16) containing uncrosslinked starting material remains open, which gap surrounds the mould cavity and is in communication with that mould cavity.
16. A process according to claim 15, wherein the mould is closed further following crosslinking shrinkage as crosslinking of the material progresses.
17. A process according to claim 16, wherein a starting material that is of at least viscous flowability prior to the crosslinking is used, and wherein starting material can flow back through the annular gap (16) into the mould cavity (15) to compensate for shrinkage.
18. A process according to any one of claims 1 to 17, wherein the starting material is a prepolymer that is a derivative of a polyvinyl alcohol having a molecular weight of at least about 2000 that, based on the number of hydroxy groups of the polyvinyl alcohol, comprises from approximately 0.5 to approximately 80 % of units of formula I wherein

    R is lower alkylene having up to 8 carbon atoms,

    R¹ is hydrogen or lower alkyl and

    R² is an olefinically unsaturated, electron-attracting, copolymerisable radical preferably having up to 25 carbon atoms.
19. A process according to claim 18, wherein the starting material is a prepolymer wherein R² is an olefinically unsaturated acyl radical of formula R³-CO-, in which R³ is an olefinically unsaturated copolymerisable radical having from 2 to 24 carbon atoms, preferably from 2 to 8 carbon atoms, especially preferably from 2 to 4 carbon atoms.
20. A process according to claim 19, wherein the starting material is a prepolymer wherein R³ is alkenyl having from 2 to 8 carbon atoms.
21. A process according to claim 18, wherein the starting material is a prepolymer wherein the radical R² is a radical of formula II         -CO-NH-(R⁴-NH-CO-O)_q-R⁵-O-CO-R³     (II) wherein

    q is zero or one and

    R⁴ and R⁵ are each independently lower alkylene having from 2 to 8 carbon atoms, arylene having from 6 to 12 carbon atoms, a saturated divalent cycloaliphatic group having from 6 to 10 carbon atoms, arylenealkylene or alkylenearylene having from 7 to 14 carbon atoms or arylenealkylenearylene having from 13 to 16 carbon atoms, and

    R³ is an olefinically unsaturated copolymerisable radical having from 2 to 24 carbon atoms, preferably from 2 to 8 carbon atoms, especially preferably from 2 to 4 carbon atoms.
22. A process according to claim 18 wherein the starting material is a derivative of a polyvinyl alcohol having a molecular weight of at least about 2000 that, based on the number of hydroxy groups of the polyvinyl alcohol, comprises from approximately 0.5 to approximately 80 % of units of formula III wherein

    R is lower alkylene,

    R¹ is hydrogen or lower alkyl,

    p is zero or one,

    q is zero or one,

    R³ is an olefinically unsaturated copolymerisable radical having from 2 to 8 carbon atoms and

    R⁴ and R⁵ are each independently lower alkylene having from 2 to 8 carbon atoms, arylene having from 6 to 12 carbon atoms, a saturated divalent cycloaliphatic group having from 6 to 10 carbon atoms, arylenealkylene or alkylenearylene having from 7 to 14 carbon atoms or arylenealkylenearylene having from 13 to 16 carbon atoms.
23. A process according to claim 22, wherein the starting material is a prepolymer wherein

    R is lower alkylene having up to 6 carbon atoms,

    p is zero and

    R³ is alkenyl having from 2 to 8 carbon atoms.
24. A process according to claim 22, wherein the starting material is a prepolymer wherein

    R is lower alkylene having up to 6 carbon atoms,

    p is one,

    q is zero,

    R⁵ is lower alkylene having from 2 to 6 carbon atoms and

    R³ is alkenyl having from 2 to 8 carbon atoms.
25. A process according to claim 22, wherein the starting material is a prepolymer wherein

    R is lower alkylene having up to 6 carbon atoms,

    p is one,

    q is one,

    R⁴ is lower alkylene having from 2 to 6 carbon atoms, phenylene, unsubstituted or substituted by lower alkyl, cyclohexylene or cyclohexylene-lower alkylene, unsubstituted or substituted by lower alkyl, phenylene-lower alkylene, lower alkylene-phenylene or phenylene-lower alkylene-phenylene,

    R⁵ is lower alkylene having from 2 to 6 carbon atoms and

    R³ is alkenyl having from 2 to 8 carbon atoms.
26. A process according to claim 18, wherein the starting material is a derivative of a polyvinyl alcohol having a molecular weight of at least about 2000 that, based on the number of hydroxy groups of the polyvinyl alcohol, comprises from approximately 1 to approximately 15 % of units of formula I.
27. A device for the manufacture of mouldings (CL), especially optical lenses, specifically contact lenses, having a closable and openable mould (1) that has a mould cavity (15) determining the shape of the moulding to be produced, which mould is intended to receive a crosslinkable starting material and is at least partially permeable to energy (3) that causes the crosslinking of the starting material and is supplied from the outside, and having an energy source (2a) and also means (2b) for the impingement of the energy upon the mould, wherein during filling of the mould cavity (15) the mould cavity is arranged in starting material (M) that is still at least partially in the uncrosslinked state.
28. A device according to claim 27, which comprises a reservoir (R) for supplying the starting material, which reservoir surrounds the mould cavity (15) and can be connected to the mould cavity (15), and wherein during filling of the mould cavity the reservoir (R) is connected to the mould cavity (15) and floods that cavity.
29. A device according to either claim 27 or claim 28, which comprises means (1a) for closing the mould (1) arranged in the starting material.
30. A device according to any one of claims 27 to 29, wherein the mould comprises a container (10a, 10b) and a mould member (11a, 11b) displaceable in that container, which mould member can be moved away from and towards the container wall (100a, 100b) lying opposite it for the purpose of opening and closing the mould, and wherein there is provided in the container an inlet (101a, 101b) through which starting material flows in between the container wall (100a, 100b) and the mould member (11a, 11b) as the mould is opened, and wherein there is provided in the container an outlet (102a, 102b) through which starting material flows out again as the mould is closed.
31. A device according to claim 30, wherein the mould comprises two mould halves, one mould half being provided on the container wall (100a, 100b) and the other on the displaceable mould member (11a, 11b).
32. A device according to claim 31, wherein the mould comprises a male mould half and a female mould half, and wherein the male mould half is provided on the container wall (100a, 100b) and the female mould half is provided on the displaceable mould member (11a, 11b).
33. A device according to any one of claims 30 to 32, wherein pumps (P1, P2) are provided which, as the mould is opened, feed in starting material through the inlet (101a, 101b) and between the container wall (100a, 100b) and the mould member (11a, 11b) and, as the mould is closed, convey starting material away again through the outlet (102a, 102b).
34. A device according to any one of claims 30 to 32, wherein means are provided for driving the displaceable mould member (11a, 11b).
35. A device according to any one of claims 27 to 34, wherein means are provided for producing a flow that separates the moulding from the mould when the mould is opened and flushes the moulding out of the mould when the mould is closed.
36. A device according to any one of claims 27 to 34, wherein a gripping device (4) is provided which removes the crosslinked moulding (CL) from the mould.
37. A device according to any one of claims 30 to 34 and according to claim 36 wherein the container (10b) comprises, on a container wall (103b) other than the shape-giving face (100b), a hollow or recess (104b) that extends substantially in the direction of movement of the displaceable mould member (11b), the gripping device (4b) being arranged in that hollow or recess (104b), and wherein the displaceable mould member (11b) comprises, on an outer wall (113b) that does not lie opposite the shape-giving container wall (100b), an indentation (114b) in which the gripping device (4b) deposits the removed moulding (CL).
38. A device according to claim 37, wherein the displaceable mould member comprises a channel (115b) that leads to the indentation (114b) and can be connected to a negative pressure or positive pressure source (P3), which channel (115b) is connected to the negative pressure source when the gripping device (4b) deposits the removed moulding (CL) in the indentation (114b) of the mould member (11b) and then is connected to the positive pressure source in order to release the lens.
39. A device according to any one of claims 31 to 38, wherein the mould is provided with spacers (19) that hold the two mould halves a small distance apart from one another when the mould is in the closed position, so that an annular gap (16) is formed that surrounds the mould cavity (15) and is in communication with that cavity.
40. A device according to claim 39, wherein the mould is provided with resilient means or displacement means that allow the two mould halves to move closer together following crosslinking shrinkage.