MXPA98001438A - Polymeric materials for fotocromi applications - Google Patents

Abstract

A polymeric material, for use as a vehicle of photochromic additives, characterized in that it comprises main chain etherethers or side chain alkoxylated groups, said polymeric material having a glass transition temperature of at least 60 ° C and an interlacing density from 3 to 8 moles per lit

Description

POLYMERIC MATERIALS FOR PHOTOCROMIC APPLICATIONS DESCRIPTIVE MEMORY This application is a continuation that forms part of the Patent of E.U.A. series No. 08 / 435,126, entitled "Adhesive Photochromic Matrix Layers for use in Optical Articles", filed on May 5, 1995, appointing Amitava Gupta, Ronald D. Blum and Venkatramani S. lyer as inventors. This application is also a continuation that forms part of the serial application No. 08 / 167,103, entitled "Method and Apparatus for Manufacturing Photochromic Lenses", filed on December 15, 1993, naming Amitava Gupta and Ronald Blum as inventors, which is a continuation that forms part of the application series No. 08 / 165,056, entitled "Method and Apparatus for Manufacturing Photochromic Lenses", filed on December 10, 1993, also naming Amitava Gupta and Ronald Blum as inventors.

FIELD OF THE INVENTION This invention relates to thin layers of materials that function as effective vehicles for photochromic additives, which can be attached to many types of optical substrates (including ophthalmic lenses, semi-finished lens blanks, optical preforms, protective goggles, shatterproof glasses, windows and windshields) , and which can be encapsulated between two layers of said optical products, at least one of which is transparent to ultraviolet light.

BACKGROUND OF THE INVENTION It is often desirable to incorporate photochromic properties into optical products which are used both in sunlight and in the dark. This allows these products to develop a dark tint that serves to reduce the external reflection during their exposure to sunlight, while also allowing them to become clear when sunlight is not present. Often a combination of three or more photochromic additives is used, each with a colored state that absorbs a particular part of the visible wavelength scale (400 to 750 NM) to obtain a brown or gray neutral color. Even though photochromic ophthalmic lenses have been successfully marketed for many years, photochromic versions of other optical products, such as windshields, windows, goggles and shatterproof glass, are not yet in common use, because it is difficult and expensive to manufacture photochromic versions of these products. Certain restrictions must also be imposed on the physical properties of the materials, particularly the plastic materials, to allow the photochromic additives incorporated therein to perform their intended function (i.e., change from a clear state to a dark state in the presence of light). solar, and return to a clear state when exposed to the extremes of sunlight). These restrictions compromise the structural and optical performance of these materials, and can make them inconvenient for their desired applications. It is useful to review the mechanism by which photochromic additives are thought to work, to further understand the deficiencies of commonly available photochromic materials, and to understand the rationale for the design of the layers that photochromic additives possess. Photochromic molecules exist in two fundamental state configurations ("doublet fundamental states"), one of which does not absorb visible radiation at some significant level, and the other of which is capable of strongly absorbing visible radiation. As shown in Figure 1, each of these fundamental state configurations has a corresponding electronically excited state. The four-state diagram of a typical organic photochromic molecule shown in Figure 1 includes two fundamental states: a colorless state, 1, and a colored state, 2, which are thermally interconvertible. For certain photochromic materials, state 2 can be converted to state 1 by the absorption of visible light. An excited state 3 formed by absorption of ultraviolet light by the ground state 1 decomposes to form an excited state., and from the excited state 4 it is decomposed to the ground state 2. The excited state 3 also decomposes directly to the ground state 2 (the activation procedure). The ground state 2 forms the excited state 4 which returns to both the ground state 1 and the ground state 2 during deactivation (the fading process), as shown in figure 1. The activated conversion of the ground state 2 into the ground state 1 introduces a temperature dependence on the dynamic scale of the photochromic response of organic photochromic materials. Thus, the higher the temperature, the faster the conversion of the ground state 2 into the ground state 1, and the equilibrium population of the ground state 2 decreases with respect to the population of the ground state 1. Consequently, with activation, the higher is the temperature, more photochromic additive exists in the colorless form 1. The elevation of the temperature barrier between the ground state 2 and the ground state 1 delays the conversion rate of the ground state 2 into the ground state 1 and, therefore, , decreases the reduction of the photochromic response ("activation level") when the temperature rises. However, at the same time, it delays the rate of change of the photochromic additive to the transparent state after it is removed from exposure to sunlight. The photochromic materials available in the state of the art therefore represent a compromise between the rate of change (measured as the time it takes for the photochromic material to return to the colorless form when the sun exposure is terminated, also referred to as the speed of the discoloration process) and the temperature dependence of the dynamic scale of the photochromic response (measured by the population of the colored form with respect to the colorless form in the thermal equilibrium when exposed to solar or ultraviolet radiation at some temperature in particular, also referred to as the activation level). For example, the Patent of E.U.A. No. 5,110,881, issued by McBain, describes a plastic material in which this advantage is changed to a better level of activation at a higher temperature, but the resulting rate of change (discoloration) is more than 5 minutes at 22.2 ° C, measured as To.s, the time needed to recover 50% of the optical transmission lost when exposed to sunlight or ultraviolet radiation ("Plastic Photochromic Eye ear: A Revolution", CN elch and JC Crano, PPG Industries Inc. ). A third deficiency of currently available photochromic materials is that said materials are generally obtained by diffusing or infusing ("imbibing") photochromic additives into bulk plastic materials, or incorporating the photochromic additives into a monomer or monomers, and subsequently polymerizing the formulation of monomer to form the bulk plastic material (see, for example, U.S. Patent No. 4,909,963 issued by Kwak and Chen, U.S. Patent No. 4,637,698 issued by Kwak and Hurditch, and U.S. Patent No. 5,185,390 issued by Fischer).

BRIEF DESCRIPTION OF THE INVENTION In view of the foregoing, an objective of the present invention is to develop plastics materials that incorporate photochromic additives, in which the rate of change is maintained at a high level, while the level of photochromic response becomes relatively insensitive to changes in color. temperature. Another objective of this invention is to develop optical products (including, but not limited to, ophthalmic lenses, protective goggles, shatterproof glasses, windows and windshields) that incorporate these materials, which are simple and inexpensive to manufacture, and whose structural and optical performance Do not be significantly compromised. In accordance with one embodiment of the invention, a polymeric material is provided which comprises major chain ether groups or side chain alkoxylated groups and which is effective as a carrier of photochromic additives. The polymeric material preferably has a glass transition temperature of at least 51.6 ° C and an entanglement density of 2 to 8 moles per liter, more preferably 2.5 to 6 moles per liter. The polymeric material preferably comprises one or more polymerized monomers selected from the group consisting of one or more mono- or multi-functional acrylates or methacrylates. Examples include bisphenol A derivatives of mono- or multi-functional acrylates or methacrylates; aromatic carbonates of mono- or multi-functional acrylates or methacrylates; aliphatic carbonates of mono- or multi-functional acrylates or methacrylates; and allyl and vinyl derivatives of mono- or multi-functional acrylates and methacrylates. Other examples include polyethylene glycol diacrylates, ethoxylated bisphenol A diacrylates, 2-phenoxyethyl methacrylates, alkoxylated trifunctional aliphatic acrylates, alkoxylated aliphatic diacrylate esters, tetrahydrofurfuryl acrylates, alkoxylated trifunctional acrylates, and alkoxylated difunctional acrylate esters. In accordance with another embodiment of the present invention, resin formulations containing monomers that can be cured to form polymeric materials, such as those described above, are provided. Examples of said monomers are described above. The resin formulations of the present invention preferably comprise a photoinitiator or a thermal initiator. Preferred photoinitiators include bis-dimethoxybenzoyltrimethylpentyl phosphine oxide, 1-hydroxycyclohexylphenyl ketone and 2-hydroxy, 2-methyl, 1-phenylpropane. Preferred thermal initiators include organic peroxides, hydroperoxides, percarbonates, peracetates and azo derivatives. The resin formulations of the present invention may also include additional additives such as antioxidants. Preferred antioxidants include tiodiethylene bis (hydrocinnamide) and bis (1, 2,2,6,6, pentamethyl-4-piperidyl) sebacate One or more photochromic additives may also be included in the resin formulations of the present invention. Preferred photochromic compounds include spiro (indoline) naphthoxazines, spiro (indoline) pyridobenzoxazines, spiro (benzolinolino) naf oxazines and octa ethyl stilbene.Optical products can be obtained from the above polymeric material or the above resin. practice of the present invention include uncorrected lenses, ophthalmic lenses, semi-finished lens blanks, optical preforms, protective goggles, shatterproof glass, windows and windshields.Mother embodiments of the present invention relate to methods for forming a polymeric material which is impregnated with a photochromic additive According to a first modality, the photochromic additive is incorporated in the matte polymeric material by adding the photochromic additive to a monomer formulation before it is polymerized. According to a second embodiment, the photochromic additive is incorporated into the polymeric material by diffusing the photochromic additive material into the polymeric material. This can be achieved in several ways. For example, the photochromic additive can be incorporated into the polymeric material by immersing it in a solution of the photochromic additives in a chemically inert solvent, spraying or spin coating the polymeric material with a solution of the photochromic additives in a chemically inert solvent, repeatedly providing a layer of surface of polymeric material, and subsequently incorporating the photochromic additive into the surface layer of the polymeric material, etc. The polymeric material, either with or without the incorporated photochromic additive, can adhere to an optical product, for example, by a region interfacial composed of an interpenetrating network, by means of an adhesive layer, etc. Another way in which the polymeric material incorporating the photochromic additive can be included in an optical product, is by forming the polymeric material that incorporates the photochromic additive as a solid powder, suspending the solid powder in a liquid, and applying the suspended powder to an optical product. Yet another way to include the polymeric material that incorporates the photochromic additive into an optical product is to partially polymerize the polymeric material; loading the polymeric material partially polymerized with the photochromic additives; dispersing the partially polymerized charged polymeric material in a fluid vehicle; and applying the fluid vehicle with the polymeric material loaded, dispersed and partially polymerized on an optical product. Other objects and advantages of the invention and alternative embodiments will become readily apparent to those skilled in the art, particularly after reading the detailed description and claims described below.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a four-state diagram of a typical organic photochromic molecule.

DETAILED DESCRIPTION OF THE INVENTION Referring to the previous description in relation to figure 1, but without wishing to depend on any theory or theory of operation in particular, it is clear that the conversion speed of ground state 2 into ground state 1 controls the level of activation, as well as also the speed of change (discoloration). Thus, the faster the conversion of the ground state 2 into the ground state 1, the lower the activation level, but the faster the fading speed. For slow bleaching systems, the activation level is controlled by the second method of converting ground state 2 to ground state 1, ie, by the absorption of visible light by ground state 2, and deactivation subsequent to form 1 , as shown in figure 1. For such slow discoloration materials, the activation level approaches a maximum, but the discoloration rate is slow. In various photochromic molecules, the rate of discoloration provided by the photochromic molecule itself is much faster than the rate of discoloration allowed by the partial rotational speeds of the plastic matrix constituting the optical product. Therefore, the rate of discoloration is determined to a large extent by the nature of the matrix, in particular its partial rotational speed. As a result, the level of activation is also determined in large part by the nature of the matrix for these photochromic molecules. Said photochromic molecules are described, for example, in the patent of E.U.A. No. 5,349,065 issued by Tanaka, Tanaka and Kida, or the patent of E.U.A. No. 5,021,196, issued by Crano, Kwiatkowski and Hurditch. Plastic products incorporating said molecules exhibit discoloration rates and matrix-dependent activation levels. A series of polymeric matrices was developed by the present inventors to be used in conjunction with said photochromic molecules which are capable of achieving high levels of activation at temperatures up to 37.7 ° C and higher, and which still retain fading rates (T0.5). less than 1 minute at room temperature (21.1ßC to 32.2ßC). A key characteristic of the polymeric matrices of the present invention is that the barrier for the conversion of the ground state 2 into the ground state 1 (Figure 1), presented by the polymer segments, contains a component that very little depends on the temperature, is say, it remains almost constant on the temperature scale of 21.1 ° C to 37.7 ° C. This is achieved by selecting appropriate monomers that, after curing them, contain constituents (either in the side chains or in the main chains) capable of undergoing rotation with a very low activation energy (less than 40 kJ / mol). A combination of said constituents is provided, so that the polymer network has several degrees of rotational freedom available thereto. At the same time, the network is interlocked to ensure that the absolute magnitude of the rotating frequency remains restricted. This is done to ensure that the speed of environment is in its glass transition temperature or above it. Therefore, all matrices are formulated to have a glass transition temperature well above the target temperature scale (-6.6 ° C or more), so that only lateral chain or local group movements exist for stimulate the conversion of ground state 2 into ground state 1 (figure 1). It was found that when monomers containing side or main chain ether groups (described in certain ethoxylated or propoxylated derivatives or methoxy substituents present as side chains) were used to formulate the polymer matrix to incorporate the photochromic additives, the matrices allowed the rapid conversion of ground state 2 into ground state 1 in the absence of entanglement, or at low levels of entanglement density. This matrix provided fast discoloration speeds, but low levels of activation at or near the upper limit of the target temperature scale. As the entanglement density increased, the conversion rate of ground state 2 into ground state 1 was retarded, simultaneously increasing the activation level to the temperature scale from 32.2 * C to 37.7 ° C. An entanglement density scale was found within which the level of activation remained almost constant (varying less than 30%) on a relatively wide temperature scale (26.6 ° C to 37.7 ° C), leaving the rate of change (velocity of discoloration) almost also unchanged at 30 to 45 seconds. It is thought that polymer matrices within this scale of entanglement densities and concentrations of ether groups present as alkoxy groups or side chains, provide an optimum number of degrees of freedom of rotation with little temperature dependence for a photochromic molecule incorporated in the matrix. Thus, a combination of polyethylene glycol diacrylate (400), ethoxylated bisphenol A diacrylate and 2-phenoxyethyl methacrylate, used as a 3 component mixture or mixed with ethylene bisalyl carbonate, provides independent control of interlacing density and glass transition temperature of the resulting polymer matrices, in addition to providing main chain ether groups and side chain alkoxylated groups in the resulting network. In addition to the monomers included above, a series of polyethylene glycol diacrylates of different molecular weights, alkoxylated trifunctional aliphatic acrylates (such as SR9008, available from Sartomer Corp) and alkoxylated aliphatic diacrylate esters (such as SR9209, available from from Sartomer Corp). In addition, other monomeric or multi-functional oligomeric acrylates or methacrylates may also be used, provided that the entanglement density scale is not 2 to 8 moles per liter, preferably 2.5 to 6 moles per liter. Preferred candidates between acrylates and methacrylates are those having aliphatic or aromatic ether bonds in the main chain, such as bisphenol A derivatives, or aromatic carbonates derived therefrom, aliphatic carbonates, as well as side chain substitutions having linkages alkoxy In addition, allyl and vinyl derivatives, such as styrene, substituted styrenes or bisalyl carbonate, or derivatives thereof can be used. The monomer formulation was photopolymerized typically using photoinitiators such as bis-dimethoxybenzoyl trimethylpentyl phosphine oxide (BAPO, available from Ciba Geigy Corp), 1-hydroxycyclohexyl phenyl ketone (Irgacure 184, available from Ciba Geigy Corp) or 2-hydroxy , 2-methyl, 1-phenylpropane (Durcure 1173, available from Radcure Corp). Alternatively, the monomer formulation can be thermally polymerized using an organic peroxide, hydroperoxide, percarbonate, peracetate or an azo derivative as a thermal polymerization initiator. Examples are benzoyl peroxide, 2,2'-azobisisobutyronitrile or diisopropylcarbonate. Antioxidants such as thiodiethylene bis (hydrocinamide) (Irganox 1035, available from Ciba Geigy Corp) or bis (l, 2,2,6,6, -pentamethyl-4-piperidyl) sebacate (Tinuvin 292, available from Ciba Geigy Corp), may also be included in the monomer formulation. Table 1 shows some typical formulations and their glass transition temperatures. The formulations are developed as usual for a given substrate material (for example, an optical product made of CR-39 (trademark of PPG Corp), bisphenol A polycarbonate or a polyurethane). In each case, the monomers are selected to develop solid bond and compatibility with the substrate to which this matrix is to be applied.

TABLE 1 List of preferred formulations for certain substrates Definition of terms: DEG-BAC: Diethylene glycol Bisalyl carbonate; PEGDA: Polyethylene glycol diacrylate; THFA: Tetrahydrofurfuryl Acrylate, EBDA: Bisphenol A Diacrylate Ethoxylate; PEMA: 2-Phenoxyethyl Methacrylate, 9008: Trifunctional Alkoxylated Acrylate, 9209: Alkyl Diffused Acrylate Ester, 184: 1-Hydroxycyclohexyl Phenyl Ketone, TIN 1130: 2-Hydroxyphenyl Benzotriazole, TIN 292: Bis (l, 2,2 Sebacate , 6,6, -Pentamethyl-4-piperidinyl).

These polymer matrices can be charged with the photochromic additives. Preferred photochromic molecules for the practice of the present invention include spiro (indolino) naphthoxazines, spiro (indolino) piidoidobenzoxazines, spiro (benzindolino) naftoxazines and octamethyl stilbene. There are several means to load the photochromic additives into the polymer matrices. For example, photochromic additives may be added to the monomer formulation prior to polymerization, provided that the additives persist at the polymerization conditions. The matrix can be imbibed with the photochromic additives, either by slow diffusion, or by taking the matrix to a temperature above its glass transition temperature, and then immersing it for a short time in a solution of the photochromic additives in a chemically inert solvent . Alternatively, the matrix can be sprayed or coated by rotation with a solution of the photochromic additive, the solvent can be evaporated, then the polymer matrix can be heated to allow the photochromic additive thus deposited on the surface to diffuse inward, and finally develop a gradient of concentration. The process for forming the matrix layer and the addition of the photochromic additives can be repeated several times until a general thickness appropriate for the contemplated application is reached. The polymeric matrices described in the present invention can be applied to optical products in various ways. For example, the polymer matrix can be developed as a layer bonded to the optical product by an interface region composed of an interpenetrating network. In another method of applying the polymer matrix to the optical product, the polymer matrix is produced in the form of a thin sheet that adhesively bonds to the optical product of interest. In yet another method of applying the polymer matrix to the optical product, the material of the polymer matrix having the photochromic additive can be formed as a solid powder, and then suspended in a liquid for coating by immersion, spraying, rotating or brushing the optical product. The matrix material will not dissolve in any solvent because it is entangled. In yet another method of applying the polymeric matrix to the optical product, the matrix material can be partially polymerized to form a sticky viscous material loaded with photochromic additives, dispersed in a fluid carrier, and then coated by dipping, spraying, rotating or with brush on the optical product. Still other modalities will become immediately apparent to those skilled in the art after reading this specification and the following claims. All patents, patent applications and other references cited in the present invention, including priority applications, are incorporated herein by reference in their entirety.

Claims (10)

NOVELTY OF THE INVENTION CLAIMS

1. - A polymeric material comprising main chain ether groups or side chain alkoxylated groups, said polymer material having a glass transition temperature of at least 51.6 ° C and an entanglement density of 2 to 8 moles per liter, and polymeric material being effective as a vehicle of photochromic additives.

2. The polymeric material of claim 1, characterized in that said polymeric material comprises one or more polymerized monomers selected from the group consisting of mono- or multi-functional acrylates or methacrylates.

3. The polymeric material of claim 2, characterized in that said monomers are selected from the group consisting of bisphenol A derivatives of mono- or multi-functional acrylates or methacrylates; aromatic carbonates of mono- or multi-functional acrylates or methacrylates; aliphatic carbonates of mono- or multi-functional acrylates or methacrylates; and allyl and vinyl derivatives of mono- or multi-functional acrylates and methacrylates.

4. The polymeric material of claim 2, characterized in that said polymeric material comprises one or more polymerized monomers selected from the group consisting of polyethylene glycol diacrylates, ethoxylated bisphenol A diacrylates, 2-phenoxyethyl methacrylates, alkoxylated trifunctional aliphatic acrylates, esters of alkoxylated aliphatic diacrylate, tet rahydrofurfu ryl acrylates, alkoxylated trifunctional acrylates and difunctional alkoxylated acrylate esters.

5. A resin formulation comprising one or more photochromic additives and one or more monomers selected from (a) monomers selected from the group consisting of mono- or multi-functional acrylates or methacrylates, and (b) monomers which, when polymerized , form a polymeric material comprising major chain ether groups, said resin formulation having a glass transition temperature of at least 51.6 ° C and an entanglement density of 2 to 8 moles per liter after polymerization.

6. The resin formulation of claim 5, characterized in that said monomers are selected from two or more monomers of the group consisting of mono- or multi-functional acrylates or methacrylates.

7. The resin formulation of claim 6, characterized in that said monomers are selected from two or more monomers from the group consisting of bisphenol A derivatives of mono- or multi-functional acrylates or methacrylates; aromatic carbonates of mono- or multi-functional acrylates or methacrylates; aliphatic carbonates of mono- or multi-functional acrylates or methacrylates; and allyl and vinyl derivatives of mono- or multi-functional acrylates or methacrylates.

8. The resin formulation of claim 6, characterized in that said monomers are selected from two or more monomers from the group consisting of polyethylene glycol diacrylates, ethoxylated bisphenol A diacrylates, 2-phenoxyethyl methacrylates, alkoxylated trifunctional aliphatic acrylates, esters of alkoxylated aliphatic diacrylate, tetrahydrofurfuryl acrylates, alkoxylated trifunctional acrylates and alkoxylated difunctional acrylate esters.

9. A method for forming a polymer material impregnated with a photochromic additive, comprising: providing a polymeric material comprising ether groups of the main chain or alkoxylated side chain groups, said polymeric material having a glass transition temperature of at least 51.6 ° C and an entanglement density of 2 to 8 moles per liter; provide a photochromic additive; incorporating said photochromic additive into said polymeric material.

10. An optical product selected from the group consisting of uncorrected lenses, ophthalmic lenses, lens lenses, optical preforms, protective glasses, shatterproof glasses, windows and windshields, said optical product comprising the polymeric material of claim 1.