MXPA97005864A - Process for the manufacture of molded articles that are partially colored, or that have regions of different colo - Google Patents

Abstract

For the rapid and rational production of molded articles, specifically contact lenses, which are partially colored, or having regions of different colors, by means of the emptying process, measured quantities of two or more crosslinkable materials (6, 7) of different sizes are introduced. colors in the casting mold (40) in the uncrosslinked state, not mixed, and after closing the casting mold, crosslink together. Through proper control of the introduction of the different crosslinkable materials with respect to location and / or time, the appearance of colors and transitions between the colors in the contact lens is influenced in a controlled manner. As the crosslinkable materials, preferably water-soluble polyvinyl alcohol derivatives containing a cross-linked radical are used.

Description

PROCESS FOR THE MANUFACTURE OF MOLDED ITEMS THAT ARE PARTIALLY COLORED, OR OOE HAVE REGIONS OF DIFFERENT COLORS The invention relates to a process for the manufacture of molded articles that are partially colored, or have regions of different colors according to the preamble of the independent claim, and to a molded article manufactured by the process, which has at least two regions , especially ring regions, of different colors. The invention relates specifically to the manufacture of optical molded articles, especially contact lenses. Colored contact lenses are very common. In many cases, there is a need for contact lenses that are not colored over their entire area, but are colored only in a central region, while the peripheral region remains substantially transparent. For the manufacture of contact lenses of a uniform color therethrough, it is known to use an appropriately dyed monomer mixture, from which contact lenses are then manufactured in a conventional manner, especially by the casting process . The emptying process is described, inter alia, in U.S. Patent No. US-A-5, 252, 056. However, in this way it is not possible to manufacture contact lenses having partially colored regions, or regions of different colors. Different processes are known for the manufacture of partially colored contact lenses. According to a known process, disclosed, for example, in U.S. Patent No. US-A-4, 553, 975, a hydrated contact lens is masked on its periphery, and immersed in a dyeing bath. The dyeing process typically lasts from 25 to 65 minutes, and is performed at temperatures of about 44 ° C. Subsequently, the dye has to be fixed, and the contact lens has to be removed in a delayed manner. In another known process, described, among other things, in the US Pat. No. US-A-5,352,245, a dry contact lens manufactured by the casting process is printed with a stamp that is still on the half male casting mold. After the printing operation, the dye has to be fixed, and the contact lens must be hydrated and removed in a delayed manner. Accordingly, a common feature of both known processes is that first a contact lens has to be made (colorless), and then it has to be stained in additional steps in a delayed manner. By means of the invention, a process of the generic kind is going to be improved, which does not require fixing of the dye and removal of the molded article, and which, consequently, makes possible a simpler and substantially faster manufacture of molded articles, especially optical molded articles, and specifically contact lenses, which are partially colored or have regions of different colors. According to the invention, the process that solves this problem is one in which measured quantities of two or more crosslinkable materials of different colors are introduced into the casting mold in the non-crosslinked state, not mixed, and after closing the mold of emptied, crosslink. By means of these measures according to the invention, the molded article, specifically the contact lens, receives its coloration during its actual manufacture, by means of the emptying process, and the laborious after-treatment which is accustomed in another way is no longer necessary. . As a result, the process is especially rapid, and is particularly suitable for the required mass production, for example, in the case of so-called daily disposable contact lenses. Other convenient measures and preferred forms of the process will be clear from the dependent claims. Through these measures, it is possible to influence the distribution of the differently colored regions, and the emergence of colors and transitions between colors in a controlled manner. The invention is described in detail below with reference to the examples, and with reference to the drawings, in which: Figure 1 shows a section through a casting mold suitable for carrying out the process of the invention. Figure 2 shows a section through a suitable introduction device, by way of example, for carrying out the process of the invention. Figure 3 shows a section, analogous to Figure 2, through a slightly modified input device. Figure 4 is a schematic representation of a color distribution in a contact lens manufactured according to a first embodiment of the process of the invention. Figure 5 is a schematic representation of a color distribution in a contact lens manufactured in accordance with a second embodiment of the process of the invention. Figure 6 shows a schematic representation of a droplet of solution in the open casting mold. Figure 6a is a schematic representation of the color distribution in a contact lens manufactured from the solution droplet shown in Figure 6. Figure 7 shows a schematic representation of another solution droplet in the open casting mold. Figure 7a is a schematic representation of the color distribution in a contact lens manufactured from the solution droplet shown in Figure 7.

The following explanations refer, purely by way of example, only to the manufacture of contact lenses. However, they also apply analogously to the manufacture of other optical molded articles, and molded articles in general. The process of the invention uses, for example, a pouring process known as described, for example, in European Patent Number EP-A-0, 637,490. In this emptying process, a measured amount of a crosslinkable material is introduced into an open casting mold in the non-crosslinked state by means of a suitable insertion device. Figure 1 shows an assembled casting mold 40 of that class. This essentially comprises two mold halves, i.e., a female mold half 41 and a male mold half 42. The concave molding surface 43 of the female dump mold half 41 determines the geometry of the front surface of a lens of contact that will be manufactured. The male pour mold half 42 has a hat shape with a convex molding surface. The convex molding surface 44 determines the geometry of the back surface of a contact lens to be manufactured. The two casting mold halves 41, 42 are usually manufactured by the injection molding process, a thermoplastic material, preferably polypropylene, is normally used as the mold material. However, more recently, preference has also been given to the use of casting molds made of glass or quartz glass, and also of metal. After a measured quantity of a crosslinkable material suitable for the manufacture of the contact lenses has been introduced into the female casting mold half 41, the casting mold is closed, the crosslinkable material is crosslinked by its exposure to a form The energy source, usually ultraviolet light, opens the casting mold again, and the finished contact lens is removed from the casting mold. However, it is also possible to leave the finished contact lens in one of the casting mold halves, and use that half of the mold as part of the package. These methods of emptying for the manufacture of contact lenses and apparatus suitable for that purpose are known in general (see, for example, U.S. Patent No. US-A-5, 252, 056 already mentioned), and therefore do not require further explanation. The crosslinkable materials suitable for the manufacture of contact lenses are known to a person skilled in the art in large numbers. By crosslinkable materials are meant in this context, for example, the monomers or the monomer mixtures and solutions thereof, especially aqueous solutions, and preferably non-crosslinked, water-soluble polymers. A suitable monomer is, for example, 2-hydroxyethyl methacrylate (HEMA) as described, inter alia, in U.S. Patent No. US-A-4, 073, 577. They are also suitable, for example. , monomer mixtures containing 2-hydroxyethyl methacrylate, as described, for example, in U.S. Patent No. US-A-4, 123, 407. However, when monomers are used, there is a drawback that subsequent extraction is required. Accordingly, the especially non-crosslinked materials are non-crosslinked water soluble polymers and solutions thereof. Water-soluble polymers are especially derivatives of polymeric 1,2- and 1,3-diols, more especially polyvinyl alcohol derivatives (PVA), or derivatives of polyvinyl alcohol copolymers. The derivatization of the corresponding 1,3-diols, such as polyvinyl alcohol, is suitably carried out by modifying a portion of the 1,3-diol groups with side chains containing crosslinkable groups, especially vinyl groups. An appropriate derivation comprises, for example, reacting portions of the 1,3-diol groups to form cyclic ketals containing an olefinically unsaturated copolymerizable electron attracting radical. Especially suitable representatives of the correspondingly derived polyvinyl alcohol are, for example, the prepolymers, which are derivatives of a polyvinyl alcohol having a molecular weight of at least about 2,000, comprising from about 0.5 to about 80 percent, based on the number of hydroxyl groups of the polyvinyl alcohol, of units of the 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 copolymerizable electron attracting radical, preferably having up to 25 carbon atoms, as described in US Pat. European Patent Number EP-A-0,641,806. R2 is, for example, an olefinically unsaturated acyl radical of the formula R3-C0-, wherein R3 is an olefinically unsaturated copolymerizable radical having from 2 to 24 carbon atoms, preferably from 2 to 8 carbon atoms, and especially from 2 to 4 carbon atoms. In another embodiment, the radical R2 is a radical of the formula II: -CO-NH- (R4-NH-CO-0) -R5-0-CO-R (II) wherein: q is 0 or 1, 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 cycloaliphatic group having from 6 to 10 carbon atoms, arylene alkylene or alkylenearylene having from 7 to 14 carbon atoms, or arylenenalkylene arylene having 13 to 16 carbon atoms, and wherein R 3 is as defined above. The variables mentioned above have especially the definitions disclosed in detail in European Patent Number EP-A-0, 641, 806, the relevant description of which is incorporated in the description of the present invention. Polymer solutions which are specifically suitable for the present invention are prepared, for example, according to Example 13 of European Patent Number EP-A-0,641,806. According to this example, 300 grams of polyvinyl alcohol (for example, Moviol Hoechst 4-88) are placed in a 2-liter double-walled reactor equipped with stirrer and thermometer, 800 grams of deionized water are added, and the mix, with stirring, at 95 ° C. After 1 hour, everything has dissolved to give a clear solution, and the solution is cooled to 20 ° C. 27 grams (0.155 moles) of methacrylamidoacetaldehyde-dimethylacetal, 440 grams of acetic acid, 100 grams of concentrated hydrochloric acid (37 percent), and a sufficient amount of deionized water are added to produce a reaction solution of 2,000 grams in total ( in the case rea: 333 grams). The mixture is stirred at 20 ° C for 20 hours. The change in acetate content can be determined by titration of acetic acid. Isolation can be performed by means of ultrafiltration: The reaction mixture is cooled to 15 ° C, and adjusted to a pH of 3.6 with aqueous NaOH (5 percent). The polymer solution is filtered on a 0.45 micron filter and purified by ultrafiltration. The ultrafiltration is carried out by means of an Omega 1 KD membrane from Filtron. The ultrafiltration is carried out until a residual content of sodium chloride of 0.004 percent is obtained. Before the purification is finished, the solution is adjusted to a pH of 7 with a 0.1 N sodium hydroxide solution. After the concentration, 1995 grams of a polymer solution are obtained at 14.54 percent (92 percent of the theory); content of N (Kjendhal determination) = 0.683 percent, acetate content (determined by hydrolysis) = 2.34 molar equivalents / gram; Inherent viscosity: 0.310; double bonds: 0.5 molar equivalents / gram (determined by microhydrogenation); free hydroxy groups (determined by reacetylation): 15.3 molar equivalents / gram; gel permeation chromatography (in water) analysis: molar percentage = 19 101, molar number 7,522, molar weight / molar number = 2.54. The isolation can also be carried out by means of precipitation: the reaction mixture is adjusted to a pH of 3.6 with triethyl amine, and is precipitated in acetone at a ratio of 1:10. The precipitate is separated, dispersed twice with ethanol and once with acetone, and dried. The product thus obtained has the same properties as that obtained by ultrafiltration. The aforementioned methacrylamide acetaldehyde dimethylacetal is obtained as follows: in a 3 liter reactor equipped with agitator and a cooling element, 220 grams (5.5 moles) of sodium hydroxide are dissolved in 300 grams of water and 700 grams of ice. The sodium hydroxide solution is cooled to 10 ° C, and 526 grams (5.0 moles) of aminoacetaldehyde-dimethylacetal and 50 milligrams of 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl are added (inhibitor of radicals). To this solution is slowly added over a period of 3.5 hours at 10 ° C, 548.6 grams (5.5 moles) of methacrylic acid chloride. When the addition is complete, the pH value slowly decreases to 7.2, and no further amine can be detected by gas chromatography. The reaction mixture is extracted with 500 milliliters of petroleum ether, in order to remove the impurities, and the aqueous phase is saturated with sodium chloride, and extracted three times with 500 milliliters of methyl tertiary butyl ether. The organic phase is dried with magnesium sulfate, filtered, and concentrated using a rotary evaporator. The resulting 882.2 grams of yellowish oil is slowly stirred by means of an Ultraturax in 2000 milliliters of petroleum ether at -10 ° C. The product is crystallized and filtered, and dried to give 713.8 grams of methacrylamidoacetaldehyde-dimethylacetal (86 percent theory), melting point 30-32 ° C, according to gas chromatography the product is 99.7 percent pure. A colorless polymer solution is prepared according to the example given above, and is used in the form of a 15 weight percent aqueous solution to prepare a solution. A colored polymer solution is prepared, for example, by stirring X g of a 15 weight percent polyvinyl alcohol (PVA) solution (according to the example given above) first for 1 minute with 5.0 milliliters of a solution of sodium carbonate at 0.5 percent by weight, and then for 3 minutes with a solution of Y mg of Duasyn-Blau-R-KG in Z ml of water. After titration with 0.01N hydrochloric acid to a pH of 7, the solution is diluted twice with 400 milliliters of water each time, and ultrafiltered on a 3kD membrane (filter) in an ultrafiltration cell (Berghof). The polymer solution colored at 15 weight percent is processed to form a solution. The examples of the figures' for X, Y, and Z are given in Table 1. To prepare the solution, 30 milliliters of a 15 weight percent aqueous polyvinyl alcohol solution, and the colored polymer solution, are concentrated using a rotary evaporator at 100 mbar and at 40 ° C, until obtaining a solids content of 33 percent by weight. This solution is stirred vigorously with 1.35 milliliters of an aqueous solution of Irgacure 2959 at 1 weight percent (photoinitiator). The solution is filled into disposable polypropylene syringes having a Luerlock connection, and the air bubbles are removed from the solution by centrifugation at 6,000 g (10 minutes). The expression "of different colors" is used to also include uncolored or colorless crosslinkable materials, and uncolored or colorless regions of contact lenses. This means, for example, that a colored polymer solution and an uncolored one are referred to as different colors. By the term "measured quantity" is meant the usual amount required to fill the casting mold in a satisfactory manner, it being also possible to provide an overfill. For simplicity, the process of the invention is described below with reference to an example, wherein only two crosslinkable materials of different colors are used, especially polymer solutions, ie, an uncolored solution and a colored solution. However, in principle, the number of crosslinkable materials of different colors that can be used in the process of the invention, and therefore, the number of regions of the finished molded article having different colors, can also be larger. It is also possible to use, in place of the aforementioned preferred polymer solutions, other crosslinkable materials described hereinbefore under the term crosslinkable materials. The introduction of the polymer solutions into the open casting mold 40, in this case the female mold half 41, is carried out by means of an introduction device 50 shown, for example, in Figure 2. The introduction device 50 comprises an insertion needle, designated as 2 in its entirety, and a containment block 20. For better understanding, the insertion needle 2 has been shown on an amplified scale relative to the containment block 20. The insertion needle 2 it contains two coaxial insertion nozzles, i.e., an internal nozzle 3, and an external annular nozzle 4. The internal nozzle 3 is separated by a partition wall 5 of the external annular nozzle 4 surrounding it coaxially. The insertion needle 2 is fixed in the containment block 20 preferably by means of adhesive (for example, an epoxy-based adhesive). The containment block 20 consists essentially of a lower part 21 and an upper part 23. The upper part 23, whose lower limiting surface is provided with a recess 25. is fixedly mounted on the lower part 21, preferably by adhesive. The upper end of the outer annular nozzle 4 ends flush with the viewing surface 22 between the upper part 23 and the lower part 21. The upper part 23 further has two holes, each of which leads, at its outer end, to a connecting piece 26, with which the disposable syringes 27 mentioned with Luerlock connection, containing the polymer solutions, are detachably coupled. One of the holes receives the dividing wall 5, which surrounds the internal nozzle 3, in such a way that the internal nozzle 3 and the dividing wall 5 extend to the associated connection piece 26. According to the above, the inner nozzle 3 and the dividing wall 5 are longer than the outer annular nozzle 4. The second hole of the upper part 23 is provided with a tube 29, one end of which leads to the associated connection piece 26, and the another end of which terminates flush with the limiting surface of the recess 25. In this way, the two polymeric solutions of different colors are introduced into the casting mold half 41 separately. The introduction device described herein is merely an example. Of course, any other introduction devices can be used to perform the process of the invention.

By means of the introduction device 50, a measured amount of a polymeric solution - either of the uncolored polymer solution 6, or of the colored polymer solution 7 - is introduced into the pouring mold half 41 from the associated disposable syringe. through the inner nozzle 3, and a measured amount of the other polymer solution is introduced into the emptying mold half 41 from the associated disposable syringe 27, through the tube 29, through the cavity formed by the recess 25 , and through the external annular nozzle 4. The two polymer solutions can be introduced into the casting mold half 41 simultaneously, with a partial overlap in time, or separately in time. During insertion, the insertion needle 2 can also be moved relative to the casting mold 40 or the casting mold half 41 simultaneously or out of phase with time. The insertion needle 2 can be moved in the direction of its longitudinal axis in such a way that, for example, the insertion needle 2 is always placed through the entire introduction process, on the surface of the solution droplet that is is producing. In another example, the insertion needle 2 can also be immersed in the solution droplet that is being produced. In addition, it is possible for the insertion needle 2 to move transversely to its longitudinal axis. In this way it is possible, for example, for the polymer solutions to be distributed over the regions of the casting mold, or for the polymer solutions of different colors to be deposited in different regions of the casting mold. These measures, whose parameters are optimized in an empirical manner, and a suitable viscosity of the crosslinkable polymer solutions, have the effect that the two polymer solutions are mixed as little as possible in the open casting mold 40. This is shown symbolically in Figure 2 for a first embodiment of the process of the invention. In the open casting mold, a droplet of solution is produced consisting of two separate regions, each containing substantially only one of the polymer solutions, either the uncolored solution 6 or the colored solution 7. The introduction device shown in FIG. Figure 3 differs from that shown in Figure 2 essentially only in the construction of the insertion needle 2, which is the reason why the containment block 20 is not drawn in Figure 3. The insertion needle 2 shown in Figure 3 it is especially suitable for performing a second embodiment of the process of the invention. In relation to the diameter of the internal nozzle 3, and with the annular diameter of the external annular nozzle 4, the dividing wall 5 is thicker than in the introduction needle shown in Figure 2. As a result, the two polymeric solutions can be introduced into the open casting mold 40, such that the colored polymer solution 7 and the uncolored polymer solution 6 are substantially separated in the open casting mold, typically being arranged in the concentric annular regions, as shown exaggerated scale in Figure 3. In a third embodiment of the process of the invention, two separate introduction operations are performed, one after the other in the same place, or spatially offset one from the other. In this way it is possible, for example, to introduce a droplet of colored solution into the open casting mold first, and then to cover it with the uncolored polymer solution. By suitable selection of the diameter and shape of the nozzles, and of the rates of introduction of the polymer solutions, it is possible to manufacture contact lenses having any desired concentric annular regions of different colors. If the dividing wall 5 between the internal nozzle 3 and the external nozzle 4 is thin (corresponding to Figure 2), a slight mixture is present on the contact surfaces of the two polymer solutions, and the color transitions in the contact lens are relatively fluid. If the insertion needle 2 shown in Figure 3 is used, in such a way that the two polymer solutions are substantially separated in space from one another, and run together only when the mold is closed, then a relatively high color limit results. clearly defined. Figures 4, 5, -6a, and 7a show schematic examples of different color distributions in contact lenses, which can be obtained in contact lenses using the three mentioned embodiments of the process of the invention. The color distribution in the contact lens occurs only after closing the casting mold, and is fixed in the closed casting mold by crosslinking the polymer solutions. Figure 2 schematically shows, among other things, a droplet of solution in the open casting mold 40, as produced by means of the insertion needle 2 according to the first mentioned embodiment. The solution droplet consists of a region containing the colored polymer solution 7, and a region containing the uncolored polymer solution 6. As the polymer solutions are introduced into the open casting mold, the insertion needle 2 is moved. in the direction of its longitudinal axis. The movement is done in such a way that the tip of the insertion needle 2 is always on the surface of the growing solution droplet throughout the introduction process. In Figure 4, the corresponding color distribution in the contact lens is shown. A colored central region 8 is followed by a concentric annular region 9 having a mixed coloration, and by an additional concentric annular region 10 which is colorless. In Figure 6, a droplet of solution can be seen which is also produced by performing the first embodiment, using the insertion needle 2 shown in Figure 2. However, in this case, the insertion needle 2 is immersed in the droplet of growing solution as the polymer solutions are introduced into the open casting mold. The corresponding color distribution in the contact lens is shown schematically in Figure 6a. The central region 11 has a mixed coloration. The attached concentric annular region 12 is colorless, and the outer concentric annular region 13 is colored / has a mixed coloration. In Figure 3, schematically, among other things, a distribution of the two polymer solutions introduced into the open casting mold by means of the insertion needle 2, according to the second mentioned modality, is shown. Before the casting mold is closed, the different polymer solutions are substantially separated in space, in this example the colored polymer solution 7 being further inwards, and the colorless polymer solution 6 being further outwards. The resulting color distribution of the same in the contact lens is schematically shown in Figure 5. The central region 14 is colored and is separated from the concentric colorless outer annular region 15 by a defined boundary in a relatively sharp manner. The solution droplet shown in Figure 7 is produced by means of the third mentioned modality. In this case, two individual introduction operations are carried out separately in time. In this example, a droplet of the colored polymer solution 7 is introduced into the open casting mold first, and then that droplet is covered with the uncolored polymer solution 6. Accordingly, the solution droplet consists of a region containing the colored polymer solution 7, and a region covering the latter, and containing the uncolored polymer solution 6. The resulting color distribution thereof in the contact lens is shown schematically in Figure 7a. The central region 16 has a mixed coloration. The attached concentric annular region 17 is colored, and the outer annular region 18 has a mixed coloration. In Table 2, a number of characteristic data of different examples of the process are summarized. For comparison purposes, the corresponding data of completely uncolored contact lenses are also given. The data is based on an insertion needle 2 having an internal nozzle 3 and an external annular nozzle 4 into which the colored polymer solution and the uncolored polymer solution, respectively, are introduced from disposable polypropylene syringes having a Luerlock connection. . The colorless and colored polymer solutions are prepared as described above.

The first column contains a serial number for the individual process examples. In the second and third columns of Table 2: A is a solution charge consisting of modified polyvinyl alcohol with a solids content of percent and Irgacure 2959 at 0.3 percent, which is substantially colorless; B is a solution load such as A, which, however, contains enough Duasyn Blau, so that the concentration of the dye in the solution is 0.05 percent; C is a solution charge such as A, which, however, contains enough Duasyn Blau, so that the concentration of the dye in the solution is 0.1 percent; In the fourth column, the figure of the drawings in which the introduction needle 2 respectively used is shown is indicated. The fifth column indicates the figure of the drawings that schematically reproduces the shape of the droplet respectively introduced; the sixth column contains the figure of the drawings showing the color distribution of the respective contact lens. Columns 7 to 9 contain geometric data of the respectively obtained contact lenses. In these columns: MT: is the thickness of the material in the center of the contact lens (average thickness). DM: is the largest diameter of the contact lens. BC: is the radius of the base curve.

In the last line of the table, provided with the serial number 19, we summarize the data typically obtained for completely colorless contact lenses manufactured in the same casting mold, for comparison purposes. The polymer solutions are introduced, for example, by means of separately controllable pressure introduction systems Model 1000 XLE from GLT GmbH. The introduction pressure is from 3 to 5.5 bar. For the manufacture of contact lenses, a male casting half made of quartz crystal (SQ1), and a female casting mold half made of Duran glass are used. The irradiation is carried out by means of UV UV lamp UVPRINT 300 CM from Dr. Hónle GmbH, using a cut-off filter of 295 nanometers, with a thickness of 2 millimeters, by Schott. The distance between the lamp housing and the cavity in the quartz mold is 14.5 centimeters. The intensity of the light in the scale of 280 to 310 nanometers, is 12.5 m / m2. The irradiation times are from 5 to 8 seconds.

In all processes, manufactured contact lenses are free from distortion. The transmission of colored contact lenses at 672 nanometers is typically 68 percent when the solution B load (MT: 0.095 millimeters) is used, and 51.5 percent when the solution C load is used. Partially colored contact lenses correspond to those of non-colored contact lenses manufactured in the same mold using only one material. In addition to the reproducibility, Table 2 demonstrates according to the foregoing the discovery that was not expected by an expert in this field, that partially colored contact lenses or contact lenses having regions of different colors can be manufactured by means of the process of the invention with the same precision and quality as non-colored contact lenses.

TABLE 1 TABLE 2 MT - desired values:

Claims (16)

NOVELTY OF THE INVENTION Having described the above invention, it is considered as a novelty, and therefore, the content of the following is claimed as property: CLAIMS

1. A process for the manufacture of molded articles, especially optical molded articles, specifically contact lenses, which are partially colored, or which have regions of different colors, from a crosslinkable material by exposure to energy, specifically radiation energy, by introducing a measured amount of the material in an open casting mold (40) in the uncrosslinked state, the casting mold closing substantially, and the material being crosslinked by its exposure to energy, where measured amounts of two or more crosslinkable materials are introduced ( 6, 7) of different colors in the casting mold (40) in the uncrosslinked state without mixing, and then crosslinked.

2. A process according to claim 1, wherein the introduction of the crosslinkable materials (6, 7) is carried out in such a way that they are mixed as little as possible in the open casting mold (40).

3. A process according to claim 2, wherein the crosslinkable materials (6, 7) are introduced into the casting mold (40) by means of coaxial introduction nozzles (3, 4).

4. A process according to claim 3, wherein the coaxial insertion nozzles (3, 4) move relative to the emptying mold (40) during the insertion process.

A process according to any of claims 1 to 4, wherein the introduction of the crosslinkable materials (6, 7) is performed in such a way that a droplet consisting of separate regions is produced, each containing substantially only one of the crosslinkable materials (6, 7), in the open casting mold (40).

6. A process according to any of claims 1 to 4, wherein the introduction of the crosslinkable materials (6, 7) is carried out in such a way that the different crosslinkable materials are substantially separated in space, especially in concentric ring regions. , in the open casting mold (40).

7. A process according to any of claims 1 to 6, wherein the crosslinkable materials (6, 7) are introduced into the casting mold (40) in a simultaneous manner.

8. A process according to any of claims 1 to 6, wherein the crosslinkable materials (6, 7) are introduced into the casting mold (40) with a partial overlap in time.

9. A process according to any of claims 1 to 6, wherein the crosslinkable materials (6, 7) are introduced into the casting mold (40) separately from one another in time.

10. A process according to any of the preceding claims, wherein one of the crosslinkable materials (6, 7) is substantially colorless.

11. A process according to any of the preceding claims, wherein the crosslinkable materials (6, 7) are water soluble polymers, especially derivatives of polymeric 1,2- or 1,3-diols, more especially derivatives of polyvinyl alcohol (PVA), or derivatives of vinyl alcohol copolymers.

A process according to any of the preceding claims, wherein the measured amounts of two or more crosslinkable materials (6, 7) of different colors that are introduced into the casting mold (40) in the non-crosslinked state, do not mixed, they crosslink together.

13. A process according to any of the preceding claims, wherein the crosslinkable materials (6, 7) of different colors, are exposed to energy, specifically radiation energy, in a simultaneous manner.

14. A molded article having at least two particularly concentric annular regions of different colors, which can be obtained by the process according to any of the preceding claims.

15. An optical molded article having at least two particularly concentric annular regions of different colors, which can be obtained by the process according to any of the preceding claims.

16. A contact lens having at least two particularly concentric annular regions of different colors, which can be obtained by the process according to any of the preceding claims.