Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2002-06-14
2004-03-30
Sellers, Robert (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C252S400610, C523S457000, C523S461000, C524S091000, C524S096000, C524S104000, C524S110000, C524S112000
Reexamination Certificate
active
06713536
ABSTRACT:
DESCRIPTION OF THE INVENTION
The present invention relates to photochromic compositions of enhanced kinetic performance and to a method for improving the performance of organic photochromic compounds in polymeric substrates. More particularly, this invention relates to compositions comprising kinetic enhancing additive(s) (KEA) and organic photochromic compound(s), and optionally, carrier, stabilizer and/or conventional additive(s). The KEA is used in an amount sufficient to improve the performance of organic photochromic compounds in polymeric organic host materials, e.g., polymerizates and polymeric coatings. The KEA(s) may be transferred prior to, after or with the photochromic compound(s) or in a combination of such steps. Still more particularly, this invention relates to photochromic articles, e.g., ophthalmic lenses, made of polymeric substrates having incorporated therein organic photochromic compounds and KEA(s) such as epoxy-containing compound(s), organic polyols and/or a mixture thereof.
Photochromic compounds exhibit a reversible change in color when exposed to radiation including ultraviolet rays, such as the ultraviolet radiation in sunlight or the light of a mercury lamp. Various classes of photochromic compounds have been synthesized and suggested for use in applications in which a sunlight-induced reversible color change or darkening is desired. The most widely described classes are oxazines, chromenes and fulgides.
Photochromic compounds may be incorporated into plastic substrates, such as ophthalmic lenses, by various methods described in the art. Such methods include dissolving or dispersing the compound within the surface of a substrate, e.g., imbibition of the photochromic compound into the substrate by immersion of the substrate in a hot solution of the photochromic compound or by depositing the photochromic compound on the surface of the substrate and thermally transferring the photochromic compound into the substrate. The term “imbibition” or “imbibe” is intended to mean and include permeation of the photochromic compound into the substrate, solvent assisted transfer absorption of the photochromic compound into the substrate, vapor phase transfer and other such transfer mechanisms.
The extent to which the photochromic compounds penetrate the polymeric substrate generally increases with increasing temperature, increasing concentration of photochromic compounds at the surface of the polymeric substrate and increasing period of contact with the polymeric substrate. The ease with which the photochromic compounds are incorporated is also dependent upon the characteristics of the photochromic compounds and of the polymeric substrate. The molecular size, melting point and solvent solubility of the photochromic compounds as well as the receptivity of the polymeric substrate all affect the ease of incorporation of the photochromic compounds. Due to the numerous variables affecting production of photochromic articles, in some cases, photochromic compounds may not be incorporated into the plastic substrate with sufficient uniformity and to a sufficient depth. This can result in poor performance of the photochromic compound and inadequate reversible color change of the photochromic article.
Methods for incorporating photochromic compounds into polymeric substrates have been disclosed in U.S. Pat. Nos. 4,286,957, 4,880,667, 5,789,015, 5,914,193 and 5,975,696. Various photochromic compositions used in the process of incorporating photochromic compounds into polymeric substrates have been disclosed in U.S. Pat. Nos. 5,185,390, 5,391,327 and 5,770,115.
The aforementioned photochromic compositions and methods of incorporating photochromic compounds into polymeric substrates are generally known in the art and can be used in the process of the present invention.
The use of epoxy-containing compounds with photochromic compounds has been disclosed in U.S. Pat. Nos. 5,395,566, 5,462,698, 5,621,017 and 5,776,376. U.S. Pat. No. 5,395,566 discloses a photochromic composition of a compound having at least one radical polymerizable group and at least one epoxy group and a photochromic compound. U.S. Pat. No. 5,462,698 discloses a photochromic composition of a compound having at least one epoxy group, a fulgide compound and two different (meth)acrylic monomers. U.S. Pat. No. 5,621,017 discloses a photochromic composition of a radical polymerization monomer, photochromic compound and photopolymerization initiator. U.S. Pat. No. 5,776,376 discloses a photochromic composition of a polymerizable monomer composed of a compound having at least one epoxy group, various monomers, an &agr;-methylstyrene dimer and photochromic compounds.
In each of the aforedescribed patents disclosing compositions containing epoxy-containing compounds and photochromic compounds, the compositions contained radically polymerizable components and were polymerized to make photochromic lenses.
Although methods exist for incorporating photochromic compounds into polymeric substrates, improvements in such methods are sought. It has now been discovered that transferring a photochromic performance improving amount of kinetic-enhancing additives and a photochromic amount of photochromic compound into an organic polymeric host will result in improved performance of a photochromic compound in the Photochromic Performance Test described in Example 25. This improvement in performance is demonstrated when the photochromic compound(s) is transferred simultaneously with the KEA, prior to the KEA, after the KEA or by using a combination of such steps.
In one contemplated embodiment, the KEA is included in a removable imbibition composition containing organic photochromic compound(s), and that optionally includes carrier, light stabilizer(s), ultraviolet light absorber(s), antioxidant(s), rheology control agents(s) and/or leveling agent(s). Photochromic articles demonstrating improved photochromic performance may be produced by the process of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
In accordance with the present invention, a KEA is defined herein as a material which when transferred into a polymeric host with photochromic compound(s), prior to the photochromic compounds, after the photochromic compounds or by a combination of at least two of such steps, results in an increased rating in the Photochromic Performance Test described in Example 25. The ratings of the test are defined as the result obtained when the change in optical density (&Dgr;OD) at 15 minutes is divided by the Bleach (T ½) and then multiplied by 10,000.
A photochromic performance improving amount of the KEA is defined herein as the amount necessary to transfer into a organic polymeric host to result in an increased rating in the Photochromic Performance Test as compared to a organic polymeric host substantially free of the KEA. This amount may be transferred into the polymeric host all at once or by first transferring a portion of the amount in one step followed by the remainder of the amount in one or more subsequent transfer steps prior to, after or with the transfer of a photochromic amount of photochromic compound(s). Materials which are KEA(s) include, but are not limited to, organic polyols, epoxy-containing compound(s) and mixtures thereof.
Other than in the operating examples, or where otherwise indicated, all numbers expressing quantities of ingredients or reaction conditions used herein are to be understood as modified in all instances by the term “about”.
The disclosures of the patents and articles cited herein related to photochromic compounds, lactone polyesters, stabilizers, poly(urea-urethanes), polymeric organic host materials, photochromic compositions, i.e., photochromic imbibition compositions, methods of incorporating photochromic compounds into a polymeric substrate and methods for producing hard or soft contact lenses are incorporated herein, in toto, by reference.
In each instance where the term “weight percent” is used herein with respect to the imbibition composition, it is to be understood that the de
Kumar Anil
Misura Michael S.
Mallak Frank P.
Sellers Robert
Transitions Optical Inc.
LandOfFree
Removable imbibition composition of photochromic compound... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Removable imbibition composition of photochromic compound..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Removable imbibition composition of photochromic compound... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3269532