MXPA97002238A - Ophthalmic lenses of high index of refraction with base of polyester resin that have optical uniformity and / or dyeing capacity better - Google Patents

Abstract

The present invention relates to a method for casting a castable and crosslinkable composition in curved ophthalmic lenses having a refractive index of at least 1.50, which comprises arranging the casting composition in a mold cavity formed between adjacent and non-planar sides of the mold and subjecting the composition to conditions sufficient to polymerize and crosslink the composition, the composition comprising: 35-36% by weight of an unsaturated polyester resin, an additive selected from the group consisting of about 15 to about 20% by weight of a monomer allyl ester, about 1% to about 20% by weight of an acrylate or mixtures thereof, and an exotherm depressant selected from the group consisting of alpha-methyl styrene, terpinolene, gamma-terpinene, dilauryl thiodipropionate, 4-tert; -butylpyrocatechol, 3-methyl catechol and mixtures thereof, to decrease the rate of polymerization of the composition, in an amount sufficient to prevent visible ripple formation in the curative composition

Description

HIGH INDEX OF REFRACTION LENSES WITH A POLYESTER RESIN BASE THAT HAVE UNIFORMITY OPTICS AND / OR IMPROVED DYEING CAPACITY FIELD OF THE INVENTION This invention is directed to compositions based on polyester resin and to methods for manufacturing and using cured polymeric articles and coatings thereof. The compositions and methods are especially useful in the manufacture of ophthalmic lenses. More particularly, the present invention is directed to polymeric articles with unsaturated polyester base, particularly ophthalmic lenses with unsaturated polyester base, which have improved optical uniformity (or lower optical distortion) and higher dyeing rate, while maintaining over time its color "water". The lenses are characterized! by a relatively high refractive index (at least about 1.5 and preferably at least about 1.56) and a relatively low density, particularly less than about 1.3 grams / cc, i.e., 1.24 grams / EC, BACKGROUND OF THE INVENTION AND PREVIOUS TECHNIQUE L > s plastic materials have been used for the manufacture of ophthalmic lenses for many years. The P1074 / 97MX plastics offer advantages for the patient on glass, mainly in terms of their lower density allowing them to have lighter lenses, and their greater resistance to impact. Conversely, plastic lenses can exhibit disadvantages: they tend to scratch more easily, have higher levels of chromatic aberration (lower ABBE heats) and can distort in higher temperature processing conditions due to glass transition temperatures (Tg) , resulting in "warped" lenses or lenses with higher levels of optical distortion Additionally, Dlastics lenses typically have lower refractive indexes when compared to glass lenses, which tend to remove lenses of increased thickness and reduced foectic attractiveness Standard lenses type "CR-39" bored from diethylene glycol bie (allyl carbonate) have a refractive index of 1498. Advances in technology have allowed mejcjras in the performance of lenses plastic, coatings have been developed that impart better scratch resistance. ABBE relatively superior lords that are adapted to diminish the effects; of chromatic aberration. Improvements in optical processing and processing equipment and machining equipment have allowed the use of materials that have P1074 / 97MX material that has a relatively high ABBE number, so that the chromatic aberration is minimized and, more importantly, a material that has an exceedingly uniform composition is required so that the occurrence of visible "ripples" is minimized .

Fast dyeing capacity Male ophthalmic lenses are manufactured in semi-laser form and sent to optical laboratories where the prescription is "refined". Due to the increasing emphasis on short waiting times for laboratories, for example service in 1 hour, the availability of lens material to quickly accept fashionable dyeing is important. In the case of semi-finished lens products, the front surface of the lenses can wear a scratch-resistant coating that does not accept the dye. In this way, the only dyeing path can be on the back surface of the original lens material. This material must be dyeable.

High index -ce of refraction and. low density The higher the refractive index the thinner are the finished lenses that will be available for a P10"/ 97MX given design.This superior index, combined especially with a relatively low density, will allow the manufacture of" thinner and lighter "final lenses., plastic ophthalmic lenses had been manufactured from a variety of materials, including polycarbonate and polyethylene methacrylate, as well as polymerized allylic compounds, epoxies, and urethanes. The most common plastic ophthalmic lenses are made, however, from bis (allyl carbonate) of diethylene glycol which is commonly referred to as "CR-39" (a specific product manufactured by PG Industries). As already mentioned before, this mater; .al has a refractive index of 1,498. It is easily processed in optical laboratories and can be manufactured with low optical distortion and easily stained by various dyeing dyes that are commercially available. The use of polyester materials to produce ophthalmic lenses has been previously disclosed in different patents of the United States. Examples of these exposures are U.S. Patent Nos. 3,391,224 and 3,513,224. U.S. Patent No. 3,391 ,: > 24 discloses a composition in which a polyether having 5 to 20 weight percent ethyl methacrylate and less than 5 weight percent is combined.

P1074 / 97MX styrene, to produce a thermofix product that can be used to produce an ophthalmic lens. Patent No. 3,513,224 discloses a composition wherein 70 to 75 weight percent of a specific unsaturated polyester formed from the reaction of fu aric acid with triethylene glycol and 2,2-dimethyl-1,3-propanediol (also known as neopentyl glycol) is combined with about 12 to 18 weight percent styrene and 8 to 12 weight percent ethylene glycol dimethacrylate. The styrene increases the refractive index to approximately 1.52 and the ethylene glycol dimethacrylate reduces the brittleness of the polymer. Several unsaturated polyester resins have been developed in commercial form which are clear when cast and have a refractive index of about 1.56 (the high refractive index is mainly attributed to the use of styrene as a crosslinking extender monomer at a level of about 30. to 45 percent). The densities of the different polyester systems are also quite low (in the order of 1.25 grams / cc). These properties are superior to those of the CR-39 (index of 1498 and density of 1.32 grams / cc) with respect to the potential for making "thinner and lighter" lenses.

P1074 / 97MX polyester can be carried out in various forms. It is quite common to use a system promoted with a material such as cobalt octane or cobalt naphthenate. When used with methyl ethyl ketone peroxide, the system can be cured close to room temperature. Other free radical polymerization techniques can also be used, including thermal curing using peroxides or diazo compounds, as well as photoinitiated curing using compounds selected from the following classes of photoinitiators: benzoin ethers, benzophenones, thioxanthones, ketals, acetophenones, and phosphine oxides. Polyester resins can be manufactured using different compositions to achieve a wide variety of physical properties (hard, soft, rigid, flexible and the like). Typical commercial polyesters include those made from a variety of glycols and acids. Common glycols used in the synthesis of alkyd and polyester include: ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, neopentyl glycol and the like. Common acids used include: italic anhydride, isophthalic acid, adipic acid and the like, which are used together with maleic anhydride and / or fumaric acid to provide the unsaturation for crosslinking, usually with styrene F1074 / 97MX and other diluent mormeros. Resins made using phthalic anhydride are commonly referred to as "ortho resins", those that are worked with isophthalic acid are commonly referred to as "iso resins". In relation to the properties desired for the production of ophthalmic lenses, typical isoresins having good scratch resistance generally have a fairly long stain. Typical ortho resins, on the other hand, are generally more prone to scratching but stain more quickly. All unsaturated polyester resins are prone to some degree of non-uniform polymerization causing internal optical distortion or visible "ripples". As already mentioned, styrene is commonly used as a crosslinking diluent monomer with unsaturated polyester compositions. As the styrene portion increases, the refractive index also increases. However, the presence of higher concentrations of styrene also tends to cause a greater degree of exotherm within the polymerization composition, which leads to the formation of optical distortions of the lens. Improve optical uniformity (decrease optical distortion) and increase the dyeing speed of an ophthalmic lens composition based on P.074 / 97MX unsaturated polyester resin while maintaining color and a high refractive index is a formidable task.

SUMMARY OF THE INVENTION Briefly, the present invention is directed to compositions based on unsaturated polyester resin that are modified to give unexpected improvement in uniformity, lower optical distortion and / or better dyeing speed by the addition of one or more additives that selected from monomeric allyl ester and / or an acrylate monomer or oligomer (weighted average molecular weight less than 1,000), together with an exotherm depressant, making the modified polyester resin-based composition commercially viable for cast ophthalmic lenses . The additive or additives and the exotherm depressant are useful for modifying the polyester for a sufficient improvement in the reduction of the optical distortion and / or an improvement in the dyeing speed, so that any unsaturated polyester resin capable of producing colorless castings and relatively transparent, a sufficient shape will be improved to provide a composition having the properties required for an ophthalmic lens. Some of the additives will need to include a highlighter dye to reach the optimal color F1074 / 97MX of the lenses. Accordingly, an aspect of the present invention is to provide unsaturated polyester resin based compositions, which include an exotherm depressant, for example alpha-methyl styrene, and an additive selected from an allyl ester, an acrylate monomer and mixtures of they, which have improved optical uniformity and / or higher dyeing speed. Orro aspect of the present invention is to provide a method for manufacturing ophthalmic lenses by polymerizing and curing polyester resin based compositions within a mold cavity, the composition contains an exotherm depressant and an additive selected from an allyl ester, an acrylate monomer and mixtures thereof, whereby the temperatures of the curing cycle are increased in essentially uniform passages, between about 80 ° F (26.67 ° C) and about 200 ° F (93.33 ° C) , preferably between about 95 ° F (35 ° C) and about 190 ° F (87.78 ° C) in a period of time from at least about 7 hours to about 20 hours, preferably from about 12 hours to about 18 hours . After finishing the curing cycle, the lenses exhibit excellent optical uniformity. Another aspect of the present invention is the P1074 / 97MX provide a method for manufacturing ophthalmic lenses by polymerizing and curing polyester resin based compositions, within a curved mold cavity, wherein the composition includes an exotherm depressor to decrease the polymerization rate , and at least two thermal polymerization initiators. An initiator, for example, di- (4-tert-butylcyclohexyl) peroxydicarbonate, is effective to initiate the polymerization over a shorter polymerization temperature range, for example from about 95 ° F (35 ° C) to about 150 ° F ( 65.56 ° C); a second thermal initiator, for example tert-butylperoxy-2-ethyl hexanoate, is effective to initiate polymerization on an upper portion of the polymerization and the range of curing temperatures, for example, between about 150 ° F (65.56 ° C) to approximately 190 ° F (87.78 ° C). These aspects and advantages of the present invention as well as others will be more clearly demonstrated from the following detailed description of the preferred embodiments of the invention.

DETAILED DESCRIPTION OF THE PREFERRED MODALITIES Compositions of this invention include an unsaturated polyester resin as a portion P1074 / 97MX predominant composition (more than 50% by weight, preferably more than about 70% by weight, eg, from about 70% to about 85% by weight of the composition). Unsaturated polyesters are well known and can be manufactured by the reaction of one or more polyols with one or more carboxylic acids, olefinic unsaturation is provided by one or more of the reactants, usually the acid. The resulting unsaturation in the polyester allows these resins to form cross-linked reaction products and thermosets with compounds containing double olefinic bonds, for example styrene and / or methyl methacrylate. Commercially available unsaturated polyesters which can be used according to the present invention include the reaction products of one or more saturated or unsaturated dicarboxylic acids, or their ester-forming derivatives, with a polyhydric alcohol containing the vinyl group or with a saturated alcohol . Examples of suitable unsaturated dicarboxylic acids include aleonic acid, fumaric acid, citraconic acid, itaconic acid, meconic acid, and anhydrides thereof, lower alkyl esters or acid halides thereof. Examples of suitable saturated dicarboxylic acids include aliphatic dicarboxylic acids, such as P1074 / 97MX malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, piicic acid, or sebacic acid; and aromatic dicarboxylic acids such as orthophthalic acid, terephthalic acid, isophthalic acid, m-p-diphenyl dicarboxylic acid and diphenic acid; and anhydrides of these acids such as phthalic anhydride and maleic anhydride, lower alkyl ethers or acid halides of these acids and mixtures thereof. Examples of suitable polyols include ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, diethylene glycol, dipropylene glycol, triethylene glycol, poly (ethylene glycols) and mixtures thereof. The polyester-based resins that are used in the compositions and methods of this invention should have a number average molecular weight in the range of from about 1,000 to about 5,000, preferably from about 1,500 to about 4,000 and should not exhibit haze. Suitable unsaturated polyesters having these properties are well known in the art. As examples of suitable unsaturated polyester resins, the polyester base may be a polyester formed by the reaction of propylene glycol, phthalic anhydride and maleic anhydride, for example the "S-40" an unsaturated polyester disclosed by Bright in the US Pat.

P1 074 / 97MX United No. 5,319,007. The compositions set forth in the Bright patent include a phenoxyethyl acrylate, which is not included as an acrylate additive according to the present invention. Another suitable unsaturated polyester is formed by the reaction of maleic anhydride, orthophthalic anhydride and propylene glycol, for example "Aropol L-2506-15" from Ashland Chemical Co., also disclosed in the aforementioned US Patent of Bright No. 5,319,007. Preferred polyester resins useful in accordance with the present invention are shown in the following examples and are the reaction products of one or more acids or anhydrides selected from phthalic acid, isoittalic acid, maleic acid, phthalic anhydride, maleic anhydride and mixtures particularly of two or more of these acids or anhydrides, with a polyol selected from ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol and neopentyl glycol, preferably two or more such glycols, having a number average molecular weight in the range of approximately 1,500 and 4,000. One of the most difficult problems encountered when trying to formulate a polyester resin based composition in a formulation suitable for ophthalmic lenses is to provide the casting and curing composition with sufficient optical clarity or freedom of P1074 / 97 X optical distortion. In conventional methods for molding plastic ophthalmic lenses, reagents used to form the resin are introduced between the surfaces of separate metal or glass molds, and the mold sections are sealed together around their internal periphery by means of a retaining ring or resilient, non-reactive packing. As exothermic materials are used, the outer surfaces of the mold are immersed in a cooling fluid, for example, water, or cooled to dissipate the polymerization and crosslinking heat from the mold cavity to maintain an optimum polymerization temperature and cured. During the polymerization reaction, particularly before gelation and crosslinking, convection currents are created in the resin, while the resin is in the liquid state, as a result of the substance, temperature difference between the polymerization resin in the cavity of mold and the coolant that surrounds the mold. These convection currents tend to freeze within the polymer as the polymerization proceeds through gelation and curing, resulting in visible flute or "ripples" in the cured polyester resin. Lenses containing these visible "ripples" are not acceptable due to wide optical distortion or optical non-uniformity.

P1074 / 97MX According to an important feature of the present invention, it has been found that in addition to an exotherm depressant for the unsaturated polyester resin base composition, a sufficiently low reaction rate results (the polymerization proceeds more slow for a long period of time) to reduce convection currents sufficiently to avoid visible ridges or "ripples". The resultant cured, unsaturated polyester based lens material has excellent optical uniformity with low optical distortion. Suitable exotherm depressants for the unsaturated polyester base compositions of the present invention include, for example, alpha methyl styrene; terpinolene; gamma-terpineno; dilauryl thiodipropionate; 4-tert-butylpyrocatechol; and mixtures thereof. The exotherm depressant should be included in the composition in an amount of at least about 0.01% by weight of the composition up to about 20% by weight, depending on the depressor used. 'Zl alpha methyl styrene is preferably used in an amount in the range between about 2% and 10% by weight, more preferably between 5.5% and 7% by weight of the composition. In addition to the exotherm depressant, it has been found that the unsaturated polyester must include an additive P1074 / 97MX selected from the group consisting of allyl ester, an acrylate monomer and mixtures thereof, to provide improved dyeing speed and / or improved optical uniformity. Any low color allyl ester and any low color acrylic monomer are suitable as additives according to the present invention. Suitable allyl esters include monoallyl esters, diallyl esters and triallyl esters, preferably an allyl ester selected from the group consisting of diallyl phthalate; bis (allyl carbonate) of diethylene glycol; triallyl cyanurate and mixtures thereof. Other suitable allyl esters include allyl acrylate; triallyl eylylbenzene isocyanurate; diallyl alloate; diallyl diglycolate; dimethalyl maleate; allyl benzoate, diallyl adipate; and mixtures thereof. The allylic ester, when incorporated as a composition additive, should be included in an amount in the range of about 1% to 20%, based on the total weight of the polyester-based lens composition, preferably between about 2% and 10% by weight; more preferably between about 6% and 10% by weight, achieving better results between about 7.5% and 9% by weight. As shown in the following examples, improvements in optical distortion and / or P1074 / 97MX dyeing speed either with the allyl ester or with an acrylate monomer, when used together with an exotherm depressor. Better results are achieved when a combination of allyl ester and acrylate monomer is used, particularly because the allyl ester also functions to increase the impact strength of the crosslinked polymer network, and the acrylate functions additionally to increase the abrasion resistance . Suitable acrylic monomers include monoacrylates, diacrylates, triacrylates, tetraacrylates, pentaacrylates, and higher polyfunctional acrylates. The preferred acrylate monomer is selected from the group consisting of d = methyl methacrylate; ethylene glycol dimethacrylate; 1,6-hexanediol diacrylate; polyoxyethylene trimethylolpropane triacrylate; dipentaerythritol pentaacrylate; and mixtures thereof. Other suitable monofunctional acrylates include acrylates and alkyl methacrylates and substituted alkyl, for example, ethyl acrylate; cyclohexyl methacrylate; 2-hydroxyethyl methacrylate; 3-hydroxypropyl acrylate; and mixtures thereof. Suitable monofunctional methacrylates and acrylates include any haloalkyl acrylate and methacrylate for example alpha-] oromoethyl acrylate; alpha-chloroethyl acrylate; chloromethyl methacrylate; 2-bromoethyl methacrylate; Y P1074 / 97MX mixtures thereof. The aryl acrylates and methacrylates are also suitable as the additive of the composition, for example 2-naphthyl methacrylate; para-tolyl acrylate; and mixtures thereof. Also suitable are haloalkyl acrylates and haloaryl methacrylates, such as para-chlorophenyl methacrylate; meta-bromophenyl acrylate; 2,4,6-tribromophenyl acrylate; and mixtures thereof. The benzyl acrylates and methacrylates which can be used as composition additives, according to the present invention, include benzyl acrylate; benzyl methacrylate and its derivatives, as well as para-chlorobenzyl methacrylate; meta-methoxybenzyl methacrylate; para-ethylbenzyl acrylate; and mixtures thereof. Other polyfunctional acrylates and methacrylates include polyol diacrylates and dimethacrylate such as neopentyl glycol diacrylate; polyethylene glycol dimethacrylate (400); tiodiethylene glycol dimethacrylate; and mixtures thereof. Additional useful polyfunctional acrylates and methacrylates include polyethacrylates and polyol polyacrylates, such as triacrylate pentaerythritol; glycerol triacrylate; trimethylolpropane triacrylate; tris (2-hydroxyethyl) isocyanurate trimethacrylate; and acrylate and PI074 / 97MX mono- and polyfunctional, aromatic and aliphatic urethane methacrylates; and mixtures thereof. The acrylate monomer, when incorporated as a composition additive, should be included in an amount in the range of about 1% to about 20%, based on the total weight of the polyester-based lens composition, preferably between about 2% and 10% by weight, more preferably between about 6% to about 10% by weight, and the best results are obtained in the range of between about 7.5% to about 9% by weight. The resulting lenses will have a relatively high refractive index (of about 1.56), a relatively low density (of about 1.24 grams / cc) and an acceptable ABBE value (of about 34 to 37). The lenses will have a sufficient hardness so that their surface can be worked with the optical laboratory equipment that is normally used. In addition, by adding various ultraviolet absorbing materials (such as Cyanamid Cyasorb UV5411; Ciba Geigy Tinuvin 234; and the like) and color-correcting dyes, the lenses can be made "water" in color and will not become parcels during the exposure to sunlight. The following Table of Examples demonstrates how the different compositions of additives change the P1074 / 97MX properties of lenses made with different polyester resin systems. The test methodology was the casting of semi-finished lenses in different configurations. A group of semi-laminated lenses was cast with an anterior curve of approximately 8 diopters and a posterior curve of 6 diopters, an edge thickness of 9-12 mm and a diameter of 75 mm. Another set of lenses was fitted with anterior and posterior curves of 6 diopters, an edge thickness of 9-12 mm and a diameter of 75 mm. For most of the tested formulations, lenses were also cast with an anterior curve of 4 diopters and a posterior curve of 6 diopters, with an edge thickness of 9-12 mm and a diameter of 75 mm. The amounts are given in percent by weight. All formulations were started with 0.5% by weight of di- (4-tert-butylcyclohexyl peroxydicarbonate) (AKZO Perkadox 16S) and 0.71% by weight of a 50% by weight solution of peroxy-2-ethylhexanoate of ter -butyl (AKZO Trigonox 21C50). The compositions were not promoted and thermally cured, immersing the molds in a water bath and employing the next cycle.

P1074 / 97MX For resin-only systems the initiators were dissolved in about 1% by weight of styrene. In all other cases the initiators were dissolved in additive composition. The resulting lenses for each test were evaluated for the presence of visible optical distortion ("ripples"). If each of the lens configurations for a given test group has a majority of lenses without visible optical distortion, the rating was considered as "Excellent". If one configuration had half or a majority of the lenses with visible distortion, but the other configuration (s) had a majority without distortion, the rating was considered "Good". If two configurations had half or a majority of lenses with visible optical distortion and the third configuration had a majority without distortion, the rating was "Regular". If all configurations had a majority of lenses with visible optical distortion, the rating was considered P1074 / 97MX as "Poor". A lens was selected from each test group, processed to a uniform thickness of approximately 1.5 to 2.0 mm. All lenses were stained simultaneously in gray staining solution (BPI gray) for 5 minutes at approximately 200 ° F (93.33 ° C). Those lenses that exhibited a percentage of visible light transmission after dyeing greater than or equal to 65% transmission are rated as "Very Slow"; 55% - 64%: "Slow"; 45% -54%: "Medium"; 35% - 44%: "Fast"; less than or equal to 34% of transmission was rated as "Very Fast". The hardness in the lenses of each test group was measured using a Barber Colman type 935 machine. A rating of 80 or more is considered acceptable. Examples 1 to 4 demonstrate the properties of the lenses; of polyester made from the resin started. Resins A and B are ortho-type resins, while resins C and D are iso-resins. Example 5 demonstrates the use of an additive composition that improves the optical clarity of resin C from a rating of "Poor" to a rating of "Good". The additive comprised approximately 22% by weight of the total formulation. In this composition, the additive consisted of triallyl cyanurate (46%) combined with polyoxyethylene trimethylolpropane triacrylate (18%) and P1074 / 97MX alpha-methyl styrene (36%) as the exotherm depressant. Example 6 demonstrates the use of a different additive composition to improve the optical clarity of Resin B from a rating of "Poor" to one of "Excellent". In this example, the allyl compound is diallyl phthalate (31%), the acrylate is 1,6-hexanediol diacrylate (31%) and the exotherm depressant is alpha-methyl styrene (38%). Examples 7 and 8 move to the same additive package used in Example 6 with the two iso, C and D resins. Light improvements were observed in both the optical clarity (from "Poor" improved to "Regular") and the speed of had. The composition of Resin C changed from "Very Slow" to "Slow" and the composition of Resin D changed from "Medium" to "Fast". Example 9 shows the effect of a different composition of additive wherein the allyl compound is bis (allyl carbonate) of diethylene glycol (50%) mixed with the exotherm depressor of alpha-methyl styrene (50%), and without a monomer of acrylate. The additive was 19% by weight of the formulation. A dramatic improvement in the dyeing speed was observed. The rating improved from "Medium" to "Very Fast". Example 10 illustrates the effect of improving the dyeing rate of Resin A of a mixture of P1074 / 97MX methacrylates and an acrylate, with an alpha-methyl styrene as an exotherm depressant, and without the presence of allyl ester. The composition was ethylene glycol dimethacrylate (40%), dipentaerythritol pentaacrylate (23%), methyl methacrylate (27%) and alpha methyl styrene (10%). The dyeing improved from "Medium" to "Fast". Example 11 demonstrates a surprising improvement in the dyeing rate for Resin A with a mixture of diallyl phthalate (75%) and alpha-methyl styrene (25%), and an acrylate monomer, comprising 10% of the total weight of the formulation. The dyeing speed increased from "Medium" to "Very Fast". Example 12 showed a good improvement in optical clarity and in the dyeing rate of Resin A by varying the additive composition of Example 11 to diallyl phthalate (25%) and alpha-methyl styrene (75%), the mixture comprising still 10% by weight of the total formulation. The optical clarity improved from "Good" to "Excellent" and the dyeing improved from "Medium" to "Fast". Example 13 demonstrates the use of ethylene glycol dimethacrylate (25%) and alpha-methyl styrene (75%) to generate the same improvement in optical clarity of Resin A, as shown in the mixture used in Example 12; however, the dyeing speed was reduced a little. Examples 14 to 16 show the effect of varying P1074 / 97MX the additive percentage of the complete formulation. Here the additive is a mixture of bis (allyl carbonate) of diethylene glycol (36%), dipentaerythritol pentaacrylate (14%), methyl methacrylate (23%) and alpha-methyl styrene (27%). At a level ie 10% of additive throughout the composition, no improvement was observed.; however, as the level was raised to 20% of the total, the dyeing speed increased from "Medium" to "Fast". As the composition increases beyond 50%, the dyeing speed increases to "Very Fast", but the reduction in optical clarity and hardness is noteworthy. Examples 17 to 20 show the effect of varying the percentage of a different additive composition in the complete formulation, here, the additive is a mixture of diallyl phthalate (36%), ethylene glycol dimethacrylate (14%) methyl methacrylate ( 23%) and alpha-methyl styrene (27%). At additive levels of 20%, 23%, and 30%, the dyeing speed varied from "Medium" to "Fast" and the optical clarity improved to "Excellent." At 50% additive, the optical clarity continues to be " Excellent "while the dyeing rate increases to" Very Fast. "The hardness of this composition approximates, however, to an unacceptable level of softness.

P1074 / 97MX TABLE OF EXAMPLES Ex. Type Composition Additive Uniformity Speed BARCOL # of Additive (%) Dyeing Optic Resira 1 A None 0 Good Average 88 2 B None 0 Poor Rapid 88 3 C None 0 Poor Very Slow 88 4 D None 0 Poor Average 87 C TAC | '46%) 22 Good Very Slow 87 TMPTI. (18%) AMS (38%) 6 B DAP | '31%) 24 Excellent Average 88 HDA (31%) AMS (38%) 7 C DAP (31%) 24 Regular Slow 86 HDA (31%) AMS (38%) 8 D DAP '31%) 24 Regular Fast 85 HDA ('31%) AMS '38%) 9 A ADC '50%) 19 Good Very Fast 84 AMS '50%) 10 A EGDMP. (40%) 22 Good Quick 89 DPPA (23%) MMA [27%) AMS [10%) 11 A DAP [75%) 10 Good Very Fast 88 AMS '25%) 12 A DAP [25%) 10 Excellent Quick 89 AMS [75%) 13 A EGDM? i (25%) 10 Excellent Average 90 AMS [75%] P1074 / 97MX TABLE OF EXAMPLES - (CONTINUED) Ex. Type Composition Uniformity Speed BARCOL # of Additive (%) Dyeing Optic Resin 14 A ADC (36%) 10 Poor Average 88 DPPA (14%) MMA (23%) AMS (27%) 15 A ADC (36%) 20 Good Quick 87 DPPA (14%) MMA (23%) AMS (27%) 16 A ADC (36%) 50 Regular Very Fast 80 DPPA (14%) MMA (23 %) AMS (27%) 17 A DEAP (36%) 20 Excellent Quick 88 EGDMA (14%) MMA (23%) AMS (27%) 18 A DAP (36%) 23 Excellent Quick 88 EGDMA (14%) MMA (23%) AMS (27%) 19 A DAP (36%) 30 Excellent Quick 88 EGDMA (14%) MMA (23%) AMS (27%) 20 A DAP (36%) 50 Excellent Very Fast 80 EGDMA (14 %) MMA (23%) AMS (27%) P1174 / 7MX Table Notes: Resin A is an unsaturated, clear polyester orthoresin intermediate (Silmar D-910) formed from the reaction of phthalic anhydride, maleic anhydride, propylene glycol, ethylene glycol, and diethylene glycol and it has a numerical average molecular weight of approximately 2,200. I read Resin A contains approximately 30% by weight of styrene as a diluent monomer. Resin B is an clear, unsaturated polyester orthoresin intermediate (Silmar SD1050A) formed by the reaction of phthalic anhydride, maleic anhydride and propylene glycol, having a number average molecular weight of about 1,900. Resin B contains about 30% by weight of styrene as a diluent monomer. Resin C is an unsaturated polyester isoresin intermediate, (Silmar SD1050D) formed by the reaction of isophthalic acid, maleic anhydride, and neopentyl glycol having a number average molecular weight of about 3,100. Resin C contains about 30% by weight of styrene as a diluent monomer. Resin D is an unsaturated polyester isoresin intermediate, (Silmar SD1050E) formed by the reaction of isophthalic acid, maleic anhydride, propylene F1074 / 97MX glycol and dipropylene glycol having a number average molecular weight of about 2,400. Resin D contains about 30% by weight of styrene as a diluent monomer. The TAC is trially cyanurate. TMPTA is polyoxyethylene trimethylolpropane triacrylate (SARTOMER CD499). AMS is alpha-methyl styrene. DAP is diallyl phthalate. HDA is 1,6-hexanediol diacrylate (SARTOMER SR238). ADC is bie (allyl carbonate) of diethylene glycol - (PPG CR-39). EGDMA is ethylene glycol dimethacrylate (SARTOMER SR206). DPPA is dipentaerythritol pentaacrylate (SARTOMER SR399). MMA is methyl methacrylate. Another composition is shown in Example 21.

P1074 / 97MX EXAMPLE 21 The composition of Example 21 not only offers a great economic advantage in the manufacture of 1.56 refractive index lenses at low material costs, but also results in lenses having good mechanical performance, good optical quality and water white color, all of which are features described for the ophthalmic lens market. The viscosity of the composition is 250 centipoise at 25 ° C which can be easily handled by conventional mixing, filtering and pouring devices. By employing the thermal curing cycle provided below, the following physical properties of the uncoated lenses were obtained. refractive index 1. 556 P1 074 / 97MX Density c / cc 1.25 Inches ce drop sphere FDA 120 to 1.55 mm thick central index yellow to 14 mm thick 1.30 UV cut (5%), nm 370 The formulation of Example 21 was started with 0.5% by weight of perkadox 16S and 1.0% by weight of Trigonox 21C50. The preferred curing cycle for the composition is: Another excellent composition is shown in the Example 22 P1Q74 / 97MX EXAMPLE 22 The formulation of Example 22 was started with 0.5% by weight of Perkadox 16S and 0.71% by weight of Trigonox 21C50. The preferred curing cycle for the composition is: P107 4 / 97MX The physical properties of lenses made from this composition and by this curing cycle are: refractive index 1.562 Density g / cc 1.24 Inches drop sphere FDA 130 to 1.55 mm central thickness index yellow to 14 mm thickness 2.4 UV cut (5%), nm, 1.6mm thickness 380 The lenses of this composition exhibit improved optical uniformity with respect to those of Example 21, while maintaining good mechanical performance and color. It should be understood that this disclosure has been made only by way of preferred embodiment and that various changes may arise in the details of construction, combinations and arrangements of parts, without departing from the spirit and scope of the invention as claimed below.

P1074 / 97MX

Claims (29)

1. NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty and, therefore, the content of the following CLAIMS is claimed as property: 1. A crosslinking model composition capable of being molded and cured to form polymeric ophthalmic lenses with a refractive index of at least 1.50, characterized in that it comprises: a predominant amount of an unsaturated polyester resin; an additive selected from the group consisting of a monomer or allylic ester, an acrylate monomer, an acrylate oligomer having a weight average molecular weight of less than 1,000, and mixtures thereof; and a compound for decreasing the rate of polymerization of the composition, in an amount sufficient to prevent the formation of visible ripples in the cured composition.
2. 2. A composition according to claim 1, characterized in that the additive comprises an allyl ester monomer.
3. 3. A composition according to claim 2, characterized in that the allylic ether monomer is selected from the group consisting of a monoallyl ester, P1074 / 97MX a dialkyl ester, a triallyl ester and mixtures thereof.
4. 4. A composition according to claim 3, characterized in that the allylic ester monomer is selected from the group consisting of allyl acrylate; allylbenzene, diallyl phthalate; triallyl cyanurate; triallyl isocyanoate; diallyl maleate, diethylene glycol bis (allyl carbonate); diallyl diglycolate; p.lethylate of dimethalyl; allyl benzoate; diallyl adipate; and mixtures thereof.
5. 5. A composition according to claim 4, characterized in that the allyl ester is selected from the group consisting of diallyl phthalate, bis (allyl carbonate) of diethylene glycol, triallyl cyanurate and mixtures thereof.
6. 6. A composition according to claim 1, characterized in that the additive comprises an acrylate selected from an acrylate monomer and an acrylate oligomer having a weight molecular weight of less than about 1,000.
7. A composition according to claim 2, characterized in that the allylic ester comprises from about 1% to about 20% by weight of the total composition.
8. 8. A composition according to claim 6, P1074 / 97MX characterized in that the acrylate additive comprises from about 1% to about 20% by weight of the composition.
9. 9. A composition according to claim 1, characterized in that the additive comprises from about 1% to about 20% by weight of an allyl ester and from about 1% to about 20% by weight of acrylate monomer.
10. A composition according to claim 9, characterized in that the compound for decreasing the polymerization rate of the composition is selected from the group consisting of: alpha methyl styrene; terpinolene; dilauryl thiodipropionate; 4-tert-butylpyrocatechol; 3-methyl catechol and mixtures thereof in an amount of about 0.01% to about 20% by weight of the composition.
11. 11. A composition according to claim 10, characterized in that the allylic ester monomer and the acrylate monomer are each present in the composition in an amount from about 2% to about 10% based on the total weight of the composition, and the compound for decreasing the polymerization rate of the composition is present therein in an amount of between about 0.01% and 10% by weight of the composition. P1074 / 97MX
12. 12. A composition according to claim 1, characterized in that it also includes the polymerization initiator in an amount of about 0.01% to about 10% by weight based on the total weight of the composition.
13. 13. A composition according to claim 6, characterized in that the acrylate additive is selected from the group consisting of: methyl methacrylate; ethyl acrylate; cyclohexyl methacrylate; 2-hydroxyethyl methacrylate, 3-hydroxypropyl acrylate; alpha-bromo acrylate = lime; alpha-chloroethyl acrylate; chloromethyl methacrylate; 2-bromethyl methacrylate; 2-naphthyl methacrylate; paratolyl acrylate; parachlorophenyl methacrylate, metabromophenyl acrylate; 2, 6-tribromophenyl acrylate; para-chlorobenzyl methacrylate; meta-methoxybenzyl methacrylate, para-ethylbenzyl acrylate; ethylene glycol dimethacrylate; 1,6-hexanediol dimethacrylate; neopentyl glycol diacrylate; polyethylene glycol dimethacrylate; tiodiethylene glycol dimethacrylate; pentaerythritol triacrylate; glyceryl triacrylate, dipentaerythritol pentacrylate; trimethylol propane triacrylate; tris (2-hydroxyethyl) isocyanurate trimethacrylate; polyoxyethylene trimethylolpropane triacrylate; a urethane acrylate; a urethane methacrylate and mixtures thereof; P1Q74 / 97MX
14. 14. A composition according to claim 13, characterized in that the acrylate additive is selected from the group consisting of onoacrilate, a diacrylate, a triacrylate, a pentacrylate and mixtures thereof.
15. 15. A composition according to claim 14, characterized in that the acrylate additive is a monomer selected from the group consisting of methyl methacrylate; d: ethylene glycol methacrylate; 1,6-hexanediol diacrylate; polyoxyethylene trimethylolpropane triacrylate; dipentaerythritol pentacrylate; and mixtures thereof.
16. 16. A composition according to claim 15, characterized in that the composition comprises from about 70% to about 85% by weight of an unsaturated polyester resin; 6% to about 10% by weight of diallyl phthalate; about 1% to 5% by weight of ethylene glycol dimethacrylate; and about 3% to 8% by weight of methyl methacrylate; wherein the compound for decreasing the polymerization rate of the composition is included in the composition in an amount between about 0.01% and 9% by weight of the composition.
17. 17. A composition according to claim 16, characterized in that the compound for decreasing the polymerization rate the composition comprises alpha-methyl-styrene. P1074 / 97MX
18. 18. A composition according to claim 17, characterized in that it comprises from about 75% to 80% by weight of an unsaturated polyester resin; from about 7.5% to 9% by weight of diallyl phthalate; from about 2.5% to 4% by weight of ethylene glycol dimethacrylate; from about 4.5% to 6% by weight of methyl methacrylate; and from about 5.5% to 7% by weight in weight of alpha-ethyl-styrene.
19. 19. A composition according to claim 15, characterized in that the composition comprises from about 70% to 85% by weight of an unsaturated polyester resin; from about 6% to 10% by weight of diethylene glycol bis (allyl carbonate); from about 1% to 5% €? n weight of dipentaerythritol pentacrylate; from about 3% to 8% by weight of methyl methacrylate; and wherein the compound for decreasing the polymerization rate of the composition is included therein in an amount of about 0.01% to 9% by weight of the composition.
20. 20. A composition according to claim 19, characterized in that the compound for decreasing the polymerization rate of the composition comprises alpha-methyl styrene.
21. 21. A composition according to claim 20, characterized in that it comprises from approximately 75% to 80% P1074 / 97MX by weight of an unsaturated polyester resin; from about 7.5% to 9% by weight of bis-chloryl carbonate) of diethylene clicol; from about 2.5% to 4% by weight of dipentaerythritol pentacrylate; from about 4.5% to 6% in spite of methyl methacrylate; and from about 5.5% to 7% by weight of alpha-methyl styrene.
22. 22. A composition according to claim 21, characterized in that the unsaturated polyester resin is formed by the reaction of an acid or anhydride selected from group C [which consists of phthalic acid, isophthalic acid, maleic acid, phthalic anhydride, maleic anhydride and mixtures thereof, with a polyol selected from the group consisting of ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, neopentyl glycol and mixtures thereof.
23. 23. A composition according to claim 22, characterized in that the unsaturated polyester has a number average molecular weight in the range of between about 1,500 and 4,000.
24. 24. A method for casting a castable and crosslinkable composition so as to form curved ophthalmic lenses with a refractive index of at least 1.50, which comprises placing the casting composition in a mold cavity formed between adjacent and non-planar sides of the mold , and subject the composition to sufficient conditions P1074 / 97MX for polymerizing and crosslinking the composition, the composition is characterized in that it comprises: a predominant amount of an ethylated polyester resin; an additive selected from the group consisting of an allyl ester monomer, an acrylate monomer, an acrylate oligomer having a weight average molecular weight of less than about 1,000, and mixtures thereof; and a compound for decreasing the rate of polymerization of the composition in order to decrease the polymerization rate of said composition, in an amount sufficient to prevent the formation of visible ripples in the cured composition.
25. 25. A method according to claim 24, characterized in that the additive comprises an allyl ester monomer.
26. 26. A method according to claim 25, characterized in that the allyl ester monomer is selected from the group consisting of a diallyl phthalate, diethylene glycol bis (allyl carbonate), triallyl cyanurate and mixtures thereof.
27. 27. A method according to claim 24, characterized in that the additive comprises an acrylate monomer. P1074 / 97MX
28. 28. A method according to claim 25, characterized in that the allylic ester monomer comprises from about 1% to 20% by weight of the total composition.
29. 29. A method according to claim 27, characterized in that the acrylate monomer comprises from about 1% to 20% by weight of the composition. : 0 A method according to claim 24, characterized in that the additive comprises from about 1% to 20% by weight of an allylic ester monomer and from about 1% to 20% by weight of an acrylate monomer. 31. A method according to claim 30, characterized in that the compound for decreasing the polymerization rate of the composition comprises: alpha-methyl styrene in an amount of about 1% to 20% by weight of the composition. 32. A method according to claim 31, characterized in that the allylic ester monomer, the acrylate monomer and the alpha methyl styrene are each present in the composition in an amount of between about 2% and 10% by weight, based on the total weight of the composition. 33. A method according to claim 24, characterized in that it also includes an initiator of P1074 / 97MX polymerization in an amount of between about 0.01% to 10% based on the total weight of the composition. 34. A method according to claim 27, characterized in that the acrylate monomer is selected from the group consisting of methyl methacrylate; ethylene glycol dimethacrylate; 1,6-hexanediol diacrylate; polyoxyethylene trimethylolpropane triacrylate; dipentaerythritol pentacrylate; and mixes of the missions. 35. A method according to claim 34, characterized in that the composition comprises from about 70% to 85% by weight of an unsaturated polyester resin; from about 6% to 10% by weight of diallyl phthalate; from about 1% to 5% by weight of ethylene glycol dimethacrylate; and from about 3% to 8% by weight of methyl methacrylate; and wherein the compound for decreasing the polymerization rate of the composition is included in the composition in an amount of about 0.01% to 9% by weight of the composition. 35. A method according to claim 35, characterized in that the compound for decreasing the polymerization rate of the composition comprises alpha-methyl styrene. 37. A method according to claim 36, P1074 / 97MX characterized in that it comprises from about 75% to 80% by weight of an unsaturated polyester resin; from about 7.5% to 9% by weight of diallyl phthalate; from about 2.5% to 4% by weight of ethylene glycol dimethacrylate; from about 4.5% to 6% by weight of methyl methacrylate; and from about 5.5% to 7% by weight of alpha-methyl styrene. 38. A method according to claim 34, characterized in that the composition comprises from about 70% to 85% by weight of an unsaturated polyester resin; from about 6% to 10% by weight of diethylene glycol bis (allyl carbonate); from about 1% to 5% by weight of dipentaerythritol pentacrylate; and from about 3% to 8% by weight of methyl methacrylate; and wherein the compound for decreasing the polymerization rate of the composition is included in the composition in an amount of about 0.01% to 9% by weight of the composition. 39. A method according to claim 38, characterized in that the compound for decreasing the polymerization rate of the composition comprises alpha-methyl styrene. 40. A method according to claim 39, characterized in that it comprises from about 75% to 80% by weight of an unsaturated polyester resin; from P1074 / 97MX about 7.5% to 9% by weight of bis (allyl carbonate) of diethylene glycol; from about 2.5% to 4% by weight of dipentaerythritol pentacrylate; from about 4.5% to 6% by weight of methyl methacrylate; and from about 5.5% to 7% by weight of alpha-methyl styrene. 41. A method according to claim 33, characterized in that the polymerization initiator comprises a combination of di- (4-tert-butylcyclohexyl) peroxydicarbonate and tert-butyl peroxy-2-ethylhexanoate, each in an amount in the range of between about 0.1% and 1% by weight of the composition. 42. A method for improving the vision of an object by a human eye, comprising placing between the eye and the object a polymeric ophthalmic lens having a refractive index of at least 1.50, the ophthalmic lens is cured from a composition characterized in that it comprises: a predominant amount of an unsaturated polyester resin; an additive selected from the group consisting of an allyl ester monomer, an acrylate monomer, an acrylate oligomer having a weight-average molecular weight of less than L, 000 and mixtures thereof; and a compound for decreasing the polymerization rate of the composition in order to decrease the P1074 / 97MX polymerization rate of said composition, in an amount sufficient to avoid the formation of visible ripples in the cured composition. 43. A method according to claim 42, characterized in that the additive comprises an allyl ester monomer. 44. A method according to claim 43, characterized in that the allylic ester monomer is selected from the group consisting of a diallyl phthalate, diethylene glycol bis (allyl carbonate), triallyl cyanurate and mixtures thereof. 45. A method according to claim 42, characterized in that the additive comprises an acrylate monomer. 46. A method according to claim 43, characterized in that the allylic ester monomer comprises from about 1% to about 20% by weight of the total composition. 1 . A method according to claim 45, characterized in that the acrylate monomer comprises from about 1% to about 20% by weight of the composition. 48. A method according to claim 42, characterized in that the additive comprises from about 1% to 20% by weight of an allyl ester and of P1074 / 97MX about 1% to 20% by weight of an acrylate monomer. 49. A method according to claim 48, characterized in that the compound for decreasing the polymerization rate of the composition comprises: alpha-methyl styrene in an amount of about 1% to about 20% by weight of the composition. 50. A method according to claim 49, characterized in that the allyl ester, the acrylate monomer and the alpha-methyl styrene are each present in the composition in an amount of between about 2% and 10% by weight, based on the total weight of the composition. P1074 / 97MX