MXPA98005183A - Photocromic compositions that have a better speed of decolorac - Google Patents

Abstract

The present invention relates to a thermoplastic molding composition consisting of A) at least one resinous component selected from the group consisting of (i) a homogeneous mixture of polycarbonate resin and polycaprolactone and (ii) a copolymer of copoly (carbonate-lactone) ) and B) at least one photochromic compound selected from a group consisting of benzopyrans, naphthopyrans, spirobenzopyrans, spironaphthopyrans, spirobenzoxazines, spironaphthoxazines, fulgides and fulgimides, wherein said compound is present in a quantity of 0.01 to 1.0 parts per hundred parts by weight of said (

Description

PHOTOCROMIC COMPOSITIONS THAT HAVE A BETTER DECOLORATION SPEED BACKGROUND OF THE INVENTION The present invention relates to thermoplastic molding compositions and, more specifically, to compositions having photochromic properties. A thermoplastic molding composition is described consisting of (A) at least one resinous component selected from the group consisting of (i) a homogeneous mixture of polycarbonate resin and polycaprolactone and (ii) a copolymer of copoly (carbonate lactone) and (B) at least one compound selected from the group consisting of benzopyrans, naphthopyrans, spirobenzopyrans, spiro-naphthopyrans, spirobenzoxazines, spironaphthoxazines, fulgides and fulgimides. The composition containing the photochromic compound in an amount of 0.01 to 1.0 parts per hundred parts by weight of said (A) exhibits good photochromic properties. The photochromic molding compositions are characterized by the fact that, upon exposure to electromagnetic radiation or sunlight, they exhibit a reversible change in color and light transmission. Once the exposure to the original radiation has been discontinued, the composition returns to its original color, or colorless state. Recently, plastic photochromic materials, most notably compositions such as may be suitable for the preparation of ophthalmic lenses, films and lenses for automobile headlights, have been the focus of attention in the relevant techniques. The plastic materials as a means for the preparation of said lenses allow the preparation of lenses lighter and thinner than traditionally used glass. Also of interest are applications of photochromic technology to applications in automotive and aircraft transparencies and architecture of greenhouses and other glazing. It is known that photochromic behavior can be imparted to glass and certain plastic materials using inorganic and organic dyes, respectively. However, when these dyes are incorporated into polycarbonate based on bisphenol A, the color change of the photochromic dyes is very slow. As the transition speed is slow, the polycarbonate photochromic products can not compete commercially with the photochromic glass and the allylic resin plastics and are, therefore, unknown. The relevant technique includes US Pat. No. 3,567,605, which described a series of pyran and chromene derivatives which had been said to undergo a color change upon exposure to that radiation. US Patents are also relevant. 5,451,344 and 5,552,090, which described photochromic naphthopyrans useful in the present invention. The document 5,552,090 described the utility of said compounds in the preparation of molded photochromic articles of any of the polymeric resins, including the thermoplastic polycarbonate resins. Also relevant is US Pat. No. 4,064,195, which described a molding composition containing polycarbonate and polycaprolactone polymer. The present invention relates to a novel molding composition containing polycarbonate resin, polycaprolactone and a photochromic compound. The composition is transparent and exhibits desirable photochromic kinetics, which makes it particularly suitable in the preparation of lenses and in glazing applications. The composition of the invention demonstrates a rapid transition between dark and clear after exposure to, and elimination of, the source of radiation. In addition, the transparency of the polycarbonate is maintained together with a sufficient impact resistance, leaving it apart from the corresponding compositions based on allylic resin and glass that are currently being used in commercial photochromic applications. The thermoplastic molding composition of the present invention consists of (A) at least one resinous component, which may be a homogeneous mixture of a polycarbonate and polycaprolactone resin (PCL) or a copolymer copolymer (carbonate lactone) and (B) at least one compound selected from the group consisting of benzopyrans, naphthopyrans, spirobenzopyrans, spironaphthopyrans, spirobenzoxazines , spironaftoxazines, fulgidae and fulgimi-das. In the embodiment in which A is a mixture, the composition contains approximately 1 to 50 mole percent of polycaprolactone (the percentages indicated throughout this text refer to the percentage in relation to the total weight of the resinous components and the compound photochromic) and a positive amount of the photochromic compound, the amount being sufficient to make the composition photochromic. More preferably, the composition contains about 5 to 50% PCL, 95 to 50% polycarbonate and about 0.01 to 1.0 part, preferably 0.03 to 0.5 parts per hundred parts resin ( ppcr) of the photochromic compound. Polycaprolactone, in the context of the invention, is a polymeric resin having a weight average molecular weight of up to about 250,000, preferably 25,000 to 150,000, more preferably 30,000 to 100,000, whose molecular structure contains units that conform to 0 II [0] (- CH2-) s C] Suitable PCLs are partially crystalline resins which can be purchased commercially, such as from Union Carbide under the name Tone Polymers P-767 and P-787. The PCL preferably has a reduced viscosity (measured with 0.2 g of polymer in 100 milliliters of benzene at 30 ° C) of about 0.1 to 1.5, more preferably about 0.5 to 0.9. PCL is a linear polyester formed through the opening reaction of the e-caprolactone ring. Aromatic polycarbonates within the scope of the present invention are homopolycarbonates, copolycarbonates, branched polycarbonate and mixtures thereof. The polycarbonates generally have a weight average molecular weight of 10,000 to 200,000, preferably 20,000 to 80,000, and their melt flow rate, according to ASTM D-1238 at 300 ° C, is from about 1 to about 65 g / 10 min, preferably about 2 to 15 g / 10 min. They can be prepared, for example, by the known diphasic interface process from a carbonic acid derivative, such as phosgene, and dihydroxy compounds by polycondensation (see German Patent Application Publications 2,063,050, 2,063,052, 1,570,703) , 2,211,956, 2,211,957 and 2,248,817; French Patent 1,561,518, and the monograph H. Schnell, "Chemistry and Physics of Polycarbonates", Interscience Publishers, New York, New York, 1964, incorporated herein by reference). In the present context, suitable dihydroxy compounds for the preparation of the polycarbonates of the invention conform to structural formulas (1) or (2).

OR) (2) Wherein A represents an alkylene group of 1 to 8 carbon atoms, an alkylidene group of 2 to 8 carbon atoms, a cycloalkylene group of 5 to 15 carbon atoms, a group Cycloalkylidene of 5 to 15 carbon atoms, a carbonyl group, an oxygen atom, a sulfur atom, -SO- or -S02- or a radical that conforms to e and g both represent the number 0 to 1; Z represents F, Cl, Br or C 1 -C 4 alkyl and, if several Z radicals are substituents on an aryl radical, they can be identical or different from each other; d represents an integer from 0 to 4, and f represents an integer from 0 to 3. Among the dihydroxy compounds useful in the practice of the invention are hydroquinone, resorcinol, bis (hydroxyphenyl) alkanes, bis ( hydroxyphenyl) ethers, the bis (hydroxyphenyl) ketones, the bis (hydroxyphenyl) sulfoxides, the bis (hydroxyphenyl) sulphides, the bis (hydroxyphenyl) sulfones, the 2,2,4-trimethylcyclohexyl-1, diphenol and the a, -bis (hydroxyphenyl) diisopropylbenzenes, as well as their alkylated compounds in the nucleus. These and other suitable "" aromatic dihydroxy compounds are described, for example, in US Pat. 3,028,356, 2,999,835, 3,148,172, 2,991,273, 3,271,367 and 2,999,846, all of which are incorporated herein by reference. Other examples of suitable bisphenols are 2,2-bis (4-hydroxyphenyl) propane (bisphenol A), 2,4-bis (4-hydroxy-phenyl) -2-methylbutane 1,1-bis (4-hydroxyphenyl) cyclohexane, a, '-bis (4-hydroxyphenyl) -p-diisopropylbenzene, 2,2-bis (3-methyl-4-hydroxyphenyl) propane, 2,2-bis (3-chloro-4-hydroxyphenyl) propane, bis (3, 5-dimethyl-4-hydroxyphenyl) methane, 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane, bis- (3,5-dimethyl-4-hydroxyphenyl) sulfide, bis (3, 5-dimethyl-4-hydroxyphenyl) sulphoxide, bis (3,5-dimethyl-4-hydroxyphenyl) sulfone, dihydroxybenzophenone, 2,4-bis (3,5-dimethyl-4-hydroxyphenyl) cyclohexane,, a '-bis (3,5-dimethyl-4-hydroxyphenyl) -p-diisopropylbenzene, 2,4-trimethylcyclohexyl-1,1-diphenol and 4,4'-sulphonyldiphenol. Examples of particularly preferred aromatic bisphenols are 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane, 2,2,4-trimethylcyclohexyl-1,1. -diphenol and 1,1-bis (4-hydroxyphenyl) cyclohexane. The most preferred bisphenol is 2,2-bis (4-hydroxyphenyl) propane (bisphenol A). The polycarbonates of the invention can carry in their structure units derived from one or more of the suitable bisphenols. A further embodiment of the invention is represented by a composition in which the resinous components consist of block copolymer or random copolymer (carbonate lactone). In this embodiment of the invention, the copolymer contains from 1 to 50 mol% of units that conform to 0 [0 (- CH2-) 5 C] The preparation of said polycarbonates is well known in the art. Suitable resins in the practice of the invention include polycarbonates, copolycarbonates and terpolycarbonates based on phenolphthalein, such as those described in US Pat. 3,036,036 and 4,210,741, both incorporated herein by reference. The polycarbonates of the invention can also be branched by condensing in them small amounts, for example 0.05-2.0 mol% (relative to the bisphenols) of polyhydroxyl compounds. Polycarbonates of this type have been described, for example, in German Patent Application Publications 1,570,533, 2,116,974 and 2,113,374; in British Patents 885,442 and 1,079,821, and in US Pat. 3,544,514. The following are some examples of polyhydroxyl compounds that can be used for this purpose: phloroglucinol, 4,6-dimethyl-2,4,6-tri (4-hydroxyphenyl) heptane, 1, 3, 5-tri (4-hydroxyphenyl) benzene, 1, 1, 1-tri (4-hydroxyphenyl) ethane, tri (4-hydroxyphenyl) phenylmethane, 2,2-bis [4,4- (4,4'-dihydroxydiphenyl)] cyclohexylpropane, 2,4-bis (4-hydroxy-1-isopropylidine) phenol, 2,6-bis (2'-dihydroxy-5 '-methylbenzyl) -4-methylphenol, 2,4-dihydroxybenzoic acid, 2- (4-hydroxyphenyl) -2- (2,4-dihydroxyphenyl) propane and 1, 4-bis (4,4'-dihydroxytriphenylmethyl) benzene. Some of the other polyfunctional compounds are 2,4-dihydroxy-benzoic acid, trimesic acid, cyanuric chloride and 3,3-bis (4-hydroxyphenyl) -2-oxo-2,3-dihydroindole. In addition to the aforementioned polycondensation process, other processes for the preparation of the polycarbonates of the invention are polycondensation in a homogeneous phase and transesterifi cation. Suitable procedures are described in US Pat. here incorporated as reference 3,028,365, 2. 999,846, 3,153,008 and 2,991,273. The preferred process for the preparation of polycarbonates is the interphase polycondensation process. Other synthesis methods can be used in the formation of the polycarbonates of the invention, such as those described in US Pat. 3,912,688, incorporated herein by reference. Suitable polycarbonate resins can be purchased commercially, for example Makrolon FCR 2400, Makrolon CD 2005, Makrolon 2600, Makrolon 2800 and Makrolon 3100, all of which are bisphenol-based homopolycarbonate resins which differ in terms of their respective molecular weights and are characterized by due to the fact that their melt flow indices (RFF) according to ASTM D-1238 are approximately 16.5-24, 13-16, 7.5-13.0 and 3.5-6.5 g / 10 min ., respectively. A branched polycarbonate, such as Makrolon 1239, can also be employed. These are products of Bayer Corporation, Pittsburgh, Pennsylvania. A suitable polycarbonate resin is known in the practice of the invention and its structure and methods of preparation have been described, for example, in US Pat. 3,030,331, 3,169,121, 3,395,119, 3,729,447, 4,255,556, 4,260,731, 4,369,303 and 4,714,746, all incorporated herein by reference. Suitable dyes in the context of the invention are photochromic compounds selected from the group consisting of benzopyrans, naphthopyrans, spiro-benzopyrans, spironaphthopyrans, spirobenzoxazines, spironaphthoxazines, fulgides and fulgimides. Said photochromic compounds have been described in the literature, including US Pat. 4,826,977, 4,931,221, 5,106,998, 5,552,090, 5,628,935 and 5,565,147 (all incorporated herein by reference). The color range of the naphthopyrans suitable in the present invention is from 410 to 500 nm, whereby they impart a yellow or orange coloration in their darkened state. In the bleached or bleached condition, the materials exhibit a colorless or pale coloration. The present invention can be used in a mixture or combined with suitable organic photochromic compounds to obtain, upon activation, the formation of a neutral coloration, such as green, brown and gray. Particularly useful for this purpose are the photochromic compounds belonging to the group of naphthopyrans, spiroindolinooxazines and spiroindolinopyrans, which are known and can be purchased commercially. These have a high quantum efficiency for coloration, good sensitivity and saturated optical density and an acceptable rate of whitening or discoloration. These compounds can be represented by the following graphic formulas IA1, IA2 and IA3, where the letters a to n represent the sides of the naphthopyran rings and the numbers represent the numbering of the ring atoms of the naphthopyrans: IA2 IA3 In graphic formulas IA1, IA2 and IA3, the group represented by A is a substituted or unsubstituted heterocyclic ring, of five or six members, fused to the g, io I side of the naphthopyran and is represented by the following graphic formulas IIA a IIF: IIA IIB IIC 1ID HE IIF In the graphic formulas IIA to IID, X can be an oxygen or nitrogen atom, the nitrogen atom of which is substituted with hydrogen or a C ^ C ^ alkyl. R x can be hydrogen, substituted or unsubstituted phenyl alkyl, carboxy or alkoxy carbonyl. Preferably, Rx is hydrogen, C ^ Cj alkyl, substituted or unsubstituted phenyl, carboxy or alkoxy (^ -3) carbonyl. R2 can be hydrogen, alkyl or substituted or unsubstituted phenyl. Preferably, R 2 is hydrogen, C 1 -C 3 alkyl or substituted or unsubstituted phenyl. R3 and R4 may each be hydrogen, alkyl or phenyl. Preferably, R3 and R4 are each hydrogen, alkyl ^^ 3 or phenyl. R5 and R6 can each be hydrogen, phenyl alkyl, hydroxy, alkoxy or acetoxy. Preferably, R 5 and R 6 are each hydrogen, C 1 -C 3 alkyl, phenyl, hydroxy, C 1 -C 5 alkoxy or acetoxy. R7, R8 and R10 can each be hydrogen, CX-C6 alkyl or phenyl, with the proviso that, when R7 is phenyl, R8 is hydrogen or alkyl CL-Cg and, when R8 is phenyl, R7 is hydrogen or alkyl Preferably , R7, R8 and R10 are each hydrogen, C ^ Cj alkyl or phenyl. More preferably, Rlf R2, R3, R4, R5, R6, R7, R8 and R10 are each hydrogen or methyl. Rllf R12, R13, R14, R1S and R16 may each be hydrogen, alkoxy alkyl or phenyl. Preferably, R / R12, R13, R14, R15 and R16 are each hydrogen, C ^ Cj alkyl, Cx-C3 alkoxy or phenyl. More preferably, Rn Ri2 'Ri3' Ri4 'RIB and Ri6 are each hydrogen, methyl or methoxy. In graphic formulas IIE and IIF, R17 may be hydrogen, C1-C6 alkyl, substituted or unsubstituted phenyl or halogen. Preferably, R17 is hydrogen, C1-C3 alkyl, substituted or unsubstituted phenyl or halogen. More preferably, R17 is hydrogen, methyl or chloro. R18 can be hydrogen, CX-C6 alkyl, phenyl, carboxy, (Cx-C6) alkoxycarbonyl or haloalkoxy (Cj-C carbonyl) Preferably, R1B is hydrogen, C1-C3 alkyl, phenyl, carboxy, (Cx-C3) alkoxy carbonyl or haloalkoxy rbonyl, R19 and R20 can each be hydrogen, alkyl or phenyl.

R19 and R20 are each hydrogen, alkyl C-L-C;, or phenyl. More preferably, R18, R19 and R20 are each hydrogen or methyl. For R1-R20, the substituents of the phenyl may be C ^ Cj alkyl and the halogen or (halo) groups may be chloro or bromo. In the graphic formulas IA1, IA2 and IA3, B and B1 may each be selected from the group consisting of (i) substituted or unsubstituted aryl phenyl and naphthyl groups; (ii) the substituted or unsubstituted heterocyclic aromatic groups pyridyl, furyl, benzofuryl, thienyl and benzothienyl, and (iii) B and B 'taken together form the adamantyl group. The aryl and heterocyclic substituents of B and B 'may each be selected from the group consisting of hydroxy, C1-C3 alkyl, C1-C3 haloalkyl, which includes mono-, di- and trihalo, alkoxy-C, and alkoxy substituents , dialkylamino C ^ C-, acryloxy, methacryloxy and halogen, said halogen or groups being (halo) fluoro, chloro or bromo. Preferably, B and B 'are represented respectively by the following graphic formulas: V 0 \ IIIA IIIB In the graphic formulas IIIA and IIIB, Yx and Z1 may each be selected from the group consisting of hydrogen, C1-C3 alkyl, alkoxy fluoro and chloro; Y 2 and Z 2 are each selected from the group consisting of C 1 C alkyl, C 1 -C 6 alkoxy, hydroxy, halogen, for example chlorine, fluoro and bromo, acryloxy and methacryloxy and a and b are each integers from 0 to 2. More preferably, Y1 and Zx are each hydrogen, C1-C3 alkyl, C1-C3 alkoxy or fluoro, Y2 and Z2 are each C1-C3 alkyl or C ^ Cj alkoxy, a is the integer 0 or 1 and b is a integer from 0 to 2. Preferred naphthopyrans of the present invention are represented by the following graphic formula IB. In graphic formula IB, group A represents formulas IIA to IID 'where X is an oxygen atom and formulas IIE and IIF. The group A is fused in such a way that an oxygen atom of the formulas IIA to IIF is bonded to the carbon atom number 8 of the naphtho portion of the naphthopyran.

IB A still preferred dye can be described as substituted naphthopyrans in the 3-position of the pyran ring with (i) an aryl substituent and (ii) a phenyl substituent having a 5- or 6-membered heterocyclic ring containing oxygen and / or nitrogen fused to the carbon atoms numbers 3 and 4 of the phenyl substituent and with a heterocyclic ring containing nitrogen in the 6-position of the naphthyl portion of the naphthopyran compound. These compounds can be represented by the following graphic formula: In graphic formula I, Rx may be C 1 -C 10 alkyl, halogen or the group -0-L, where L is a C 1 -C 4 alkyl, for example methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl said nonyl, decyl, undecyl and dodecyl, said halogen being chloro, fluoro or bromo, is the integer 0, 1 or 2. Preferably, R 1 is C 1 Cg alkyl, fluoro, bromo or the group -OL, where L is Cx-C4 alkyl is already the integer 0 or 1. More preferably, Rx is C ^ Cj alkyl, fluorine or the group -OL, where L is methyl is already the integer 0 or 1. In graphic formula I, R2 it can be a saturated, unsubstituted or mono- or disubstituted nitrogen-containing heterocyclic group selected from the following groups represented by graphic formulas IA to IG: LE IF IG where E and F in the graphic formula IC are each a nitrogen or carbon atom, with the proviso that, when E is nitrogen, F is a carbon atom, and G in the graphic formula ID is a nitrogen atom, oxygen or carbon and H is a nitrogen or carbon atom, with the proviso that, when H is nitrogen, G is a carbon atom. Examples of R2 groups include aziridino, azetidino, 1-pyrrolidyl, 1-pyrrolinyl, 1-imidazolidyl, 2-imidazolin-1-yl, 2-pyrazolidyl, 3-pyrazolin-2-yl, morpholino, piperidino, piperazinyl, -methyl-l-piperazinyl, 1,4,5,6-tetrahydropyrimidinyl, 1-indolinyl, hexamethyleneimino and heptamethyleneimino. The substituents for R 2 may be alkyl and / or alkoxy. Preferably, R 2 is an unsubstituted or monosubstituted member of the group consisting of indolinyl, morpholino and piperidino. More preferably, R2 is morpholino. B can be the substituted or unsubstituted aryl group, naphthyl or phenyl, said substituents being aryl alkyl (C 1 -C 4) alkoxy (C 1 C, halogen, morpholino, piperidino or R (R ") N-, where R and R "are each hydrogen or Cx-C3 alkyl, said groups being halogen (or halo) fluoro or chloro Preferably, B is represented by the following graphic formula II: eleven In graphic formula II, R 6 is hydrogen, C 1 -C 4 alkyl, C 1 -C 4 alkoxy, fluoro or chloro and each R 7 is a C 1 -C 4 alkyl C 1 -C 4 alkoxy, hydroxy, chloro or fluoro and d is an integer of 0 a 2. Preferably, R6 is hydrogen and R7 is selected from the group consisting of chloro, methyl and methoxy. B1 may be represented by one of the following graphic formulas III or IV: III IV In graphic formulas III and IV, X is oxygen or nitrogen and Y is carbon or oxygen, with the proviso that, when X is nitrogen, Y is carbon; R4 and R5 are each hydrogen or Cx-C5 alkyl; each R3 is a CX-C5 alkyl, C1-C5 alkoxy, hydroxy or halogen, said halogenated substituent being chloro, fluoro or bromo, and c is an integer of 0 to 3, for example 0, 1, 2 or 3. Preferably, B 'is represented by graphic formula III or IV, where X is oxygen; And it's carbon or oxygen; R4 and R5 are each hydrogen or Cx-C4 alkyl; each R 3 is a C 1 -C 4 alkyl, C 1 -C 4 alkoxy, hydroxy or fluoro, and c is the integer 0, 1 or 2.

More preferably, B 'is 2,3-dihydroxybenzofuran-5-yl, 2-methyldihydroxybenzofuran-5-yl, indolin-5-yl, 1,2,3,4-tetrahydroquinolin-6-yl, chroman-6-yl or 1,3-benzodioxol-5-yl. In graphic formula III, when R4 and R5 are H and when X is oxygen and Y is carbon and c is zero, the group is a 2,3-dihydrobenzofuran-5-yl; when X is oxygen and Y is oxygen and c is zero, the group is 1,3-benzodioxol-5-yl, and when x is nitrogen and Y is carbon and c is zero, the group is indolin-5-yl. In graphic formula IV, when X is oxygen and Y is carbon, the unsubstituted group is a 6-yl chroman; when X is oxygen and Y is oxygen, the unsubstituted group is a 1,4-benzodioxan-6-yl, and when X is nitrogen and Y is carbon, the unsubstituted group is 1, 2, 3, 4-tetrahydroquinolin- 6-ilo. For reasons of brevity, these groups will be referred to herein as fused heterocyclic phenyl groups. The preferred naphthopyran dye is 3,3-diphenyl-3H-naphtho [2, 1-b] pyran, represented by the formula where Ra to R6 represent hydrogen. The spiroxazines suitable in the present invention are known: see, for example, US Pat. 3,562,172, 3,578,602, 4,215,010 and 4,342,668, all of which are incorporated herein by reference. Essentially, the spiroxazines suitable in the present invention can be described by the formula wherein: R1 and R2 independently represent a hydrogen or halogen atom (fluorine, chlorine or bromine) or a group selected from linear or branched C1-C5 alkyl, perfluoroalkyl Cx-C5, alkoxy Ci-Cg, nitro or cyano; R3 and R4 independently represent linear or branched C ^ Cg alkyl groups, phenyl or benzyl; or R3 and R4, when considered together with the carbon atom to which they are attached, form a C5-C8 cycloalkyl group; R5 represents a linear or branched alkyl group, phenyl, benzyl or allyl; R6 represents a hydrogen atom or a linear or branched C ^ Cg alkyl group, or the group -NR8R9, where R8 is a linear or branched alkyl group, phenyl or benzyl; R9 is hydrogen or has the same meaning as R8, or R8 and R9, when considered together with the nitrogen atom to which they are attached, form a cyclic structure consisting of 5-12 members and possibly containing a more selected heteroatom between oxygen and nitrogen, and R7 represents a hydrogen or halogen atom (fluorine, chlorine or bromine) or a group selected from: linear or branched C ^ Cg alkyl, alkoxy cyano, thioether and carboxylated ester with 1-3 carbon atoms in the ester portion, or represents an aromatic or heterocyclic fused ring, -X represents CH or N-. In particular, the groups Rx and R2, when they are not hydrogen, can be linked in any of positions 4, 5, 6 and 7 of the indoline part of the molecule. In addition, the R7 group, if it does not represent hydrogen or an aromatic or heterocyclic fused ring, can be present at any of the 7 ', 8', 9 'and 10' positions of the naphthalene part of the molecule. In the preferred embodiment, photochromatic compounds corresponding to the general formula (I) are used, in which: R1 and R2 independently represent a hydrogen atom or the methyl group; R3 and R4 each represent the methyl group, or together they represent the cyclohexyl group; R5 represents the methyl group; R6 represents a hydrogen atom or the group -NR8R9, where the groups R8 and R9, together with the nitrogen atom to which they are attached, form a ring structure of piperidyl, morpholyl, pyrrolidyl or hexamethyleneimino, and R7 represents a hydrogen atom. hydrogen and X represents CH. Examples of preferred photochromic compounds used according to the present invention are 1,3,3,4,5- or 1,3,3,5,6-pentamethylpyrro (indoline-2,3 '- [3H] -naphtho (2: 1). -b) - (1,4) oxazine), 1,3,3-trimethylspiro (indoline-2,3 '- [3 H] -naphtho (2, 1-b) - (1,4) oxazine), 1, 3, 3-trimethylspiro (indoline-6- (1-piperidyl) -2,3'- [3 H] -naphtho (2, 1-b) - (1,4) oxazine), 1,3,3-trimethyl spiro ( indoline-6 '- (1-morpholyl) -2,3'- [3 H] -naphtho (2, 1- b) - (1,4) oxazine), 1,3,3,4,5- or 1, 3, 3, 5, 6-pentame-0-usefulpiro (indoline-6 '- (1-piperidyl) -2, 3' - [3H] -naphtho- (2, 1-b) - (1,4) oxazine) and 1, 3, 3-trimethylspiro (indoline-6 '- (1-piperidyl) -9' - (methoxy) -2,3 '- [3 H] -naphtho- (2, 1-b) - (1,4 ) oxazine). The spiropyrans useful for the purposes of the present invention are photochromatic organic compounds which can be defined by the following general formulas (II), (III), (IV) and (V): indolinanaftopiranoB 0 (III) bßnzotiazolinaespiropiranos 15 (IV) benzoxazinespiropyrans (V) In the preceding general formulas: R 1 and R n represent alkyl or aryl groups; , R12 represents an alkyl or aryl group or a substituted alkyl group (such as hydroxyalkyl, haloalkyl, carbalkoxyalkyl, alkoxyalkyl, and annoalkyl); R 14 represents hydrogen or an alkyl, aryl or alkoxy group; R13 and R15 represent hydrogen or mono- or poly- "substitution groups, chosen from alkyl and substituted alkyl, or halogen, nitro or alkoxy groups. The fulgidae and fulgicides suitable in the context of the invention are known and have been described in literature (see, for example, Applied Photochromic 5 Polymer Systems, Edited by CB McArdle, Blackie USA: Chap an & Hall, New York, 1992, pp. 80-120), incorporated herein by reference. The composition of the invention can be used in applications that require photochromic materials to those that have been previously referred to. Photochromic lenses such as those described in US Pat. 5,531,940, the description of which is incorporated herein by reference. The invention is further illustrated, but without intending to limit it, by the following examples, in which all parts and percentages are by weight, unless otherwise specified. EXPERIMENTAL: Compositions according to the invention were prepared and their photochromic properties were determined. In order to measure the darkening rate, the samples were exposed to UV radiation (Spectrolin lamp of long wavelength -365 nm) for ten minutes. Absorbance was recorded at the maximum peak of the dye (424 nm for Yellow L variance) at 4 second intervals over a period of 10 minutes using a spectrophotometer (Perkin-Elmer Lambda 9 UV / Vis). The rate of discoloration was measured in a similar manner after first removing the source of UV radiation. When the UV radiation affects the samples that were studied, the incorporated photochromic dye begins to develop from a colorless state or a colored state. More color develops as exposure to UV radiation continues, until the color intensity reaches a substantially constant plateau. Since the absorbance also increases when the photochromic dye becomes a colorless state in a colored state, this value is a convenient measure of the rate at which the material darkens. In the following table, T1 / 2 refers to the time (in seconds) required to revert to 50% absorbance. As shown by the results shown in the following table, the control composition containing only polycarbonate and the dye of the invention showed a slow rate of darkening and discoloration; their T1 / 2 values were 4 minutes and 5 seconds. PCL molded articles are opaque and compositions containing only PCL and the dye of the invention are unsuitable for applications where transparency is a requirement. The compositions prepared and evaluated as follows, contained, as PCL, Tone 767 of Union Carbide, a resin characterized by the fact that its weight-average molecular weight is 50,000 g / mol. The dye used in the examples, at a level of 0.1 ppcr, was 3, 3-diphenyl-3H-naphtho [2, 1-b] pyran. The table shows the inverse rates of discoloration. Table 1 Resinous components (% p) (1) The polycarbonate resin was Makrolon 2458 homopolycarbonate based on bisphenol A, with a melt flow rate according to ASTM D-1238 of about 20 g / 10 min. (2) A copolycarbonate based on bisphenol A (65%) and 2,2,4-trimethylcyclohexyl-1,2-diphenol (35%). The results show the effectiveness of the dyes of the invention in making the composition suitable as a photochromic composition.

The photochromic performance of a composition of the invention is further demonstrated by the results of its darkening and discoloration as indicated below. The darkening rates of Compositions 1-1 and 1-2 above, after exposure of the test specimens (100 mils in thickness) to a light source of 424 nm, are shown in Table 2. Table 2 Absorbance after exposure to UV radiation Time (minutes) Table 3 shows the rate of discoloration after removing these specimens (Compositions 1-1 and 1-2) from the light source. Table 3 Fading time (seconds) (1) The 50% discoloration time refers to the time interval from which the totally darkened material was removed from the light source until the reversion reached 50% of the maximum darkening. () The 30% discoloration time refers to the time interval from which the completely darkened material was removed from the light source until the reversion reached 30% of the maximum darkening. In an additional parallel group of experiments, the photochromic compound used was spiroxazine, according to: The results were the following Table 4 Resinous components (% p) 111 The polycarbonate resin was Makrolon 2458 homopolycarbonate based on bisphenol A, with a melt flow rate according to ASTM D-1238 of about 20 g / 10 min. , 2) A copolycarbonate based on bisphenol A (65%) and 2,2,4-trimethylcyclohexyl-1,1-diphenol (35%). The photochromic performance of the compositions of the invention is further demonstrated by the darkening and discoloration results indicated below. Table 5 shows the darkening rates of the above Compositions 4-1 and 4-2, after exposing the test specimens (100 mils thick) to a 610 nm light source. Table 5 Absorbance after exposure to UV radiation Time (minutes) Table 6 shows the discoloration rate after removing these specimens (Compositions 4-1 and 4-2) from the light source. Table 6 Discoloration time (seconds) (1) The 50% discoloration time refers to the time interval from which the total obscured material was removed from the light source until the reversion reached 50% of the maximum darkening. < 2) The 30% discoloration time refers to the time interval from which the totally darkened material was removed from the light source until the reversion reached 30% of the maximum darkening. Although the invention has been described in detail in the foregoing for illustrative purposes, it is to be understood that said detail has only that purpose and that those skilled in the art can make variations therein without departing from the spirit and scope of the invention, except in what may be limited by the claims.

Claims (2)

1. CLAIMS 1. A thermoplastic molding composition consisting of (A) at least one resinous component selected from the group consisting of (i) a homogeneous mixture of polycarbonate resin and polycaprolactone and (ii) a copolymer copolymer (carbonate-lactone) and (B) at least one photochromic compound selected from the group consisting of benzopyrans, naphthopyrans, spirobenzopyrans, spironaphthopyrans, spirobenzoxazines, spironaphthoxazines, fulgides and fulgimides, wherein said compound is present in an amount of 0.01 to 1.0 parts. per hundred parts by weight of said (A).
2. 2. The thermoplastic molding composition of Claim 1, wherein said (ii) is a block copolymer containing from 1 to 50 mol% of units that conform to 0 II [or (-CH2-) 5 C] 3. The thermoplastic molding composition of Claim 1, wherein said (ii) is a random copolymer containing from 1 to 50 mol% of units that conform to 0 II [0 (-CH2-) 5 C] 4. The composition of Claim 1, wherein said (B) is a benzopyran. 5. The composition of Claim 1, wherein said (B) is a naphthopyran. 6. The composition of Claim 1, wherein said (B) is a spirobenzopyran. The composition of Claim 1, wherein said (B) is a spirobenzoxazine. 9. The composition of Claim 1, wherein said (B) is a spironaphthoxazine. 10. The composition of Claim 1, wherein said (B) is a fulgida. 11. The composition of Claim 1, wherein said (B) is a fulgimide. 12. The composition of Claim 1, wherein said compound conforms to where Rx is C ^ C ^ alkyl, halogen or the group -O-L, where L is a C1-C12 alkyl; a represents 0, 1 or 2; R2 is a heterocyclic group containing saturated nitrogen; B is an aryl group and B 'is selected from the group consisting of III and IV III IV where X is oxygen or nitrogen and Y is carbon or oxygen, with the proviso that, when X is nitrogen, Y is carbon, and where R4 and R5 represent hydrogen or alkyl R3 is a C1-C5 alkoxy alkyl, hydroxy or an atom of halogen and c is an integer from 0 to 3. 13. The composition of Claim 1, wherein said compound is where Rx to R6 represent hydrogen. 14. The composition of Claim 1, wherein said compound is 15. The composition of Claim 1, wherein said compound is present in an amount of 0.03 to 5 parts per hundred parts by weight of said (A). 16. The thermoplastic molding composition of Claim 1, wherein said (i) contains about 5 to 50 percent polycaprolactone relative to the weight of said blend.