US 3565814 A
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3,565,814 SITIONS IN A LAURYL METHACRYL ATE Feb. 23, 1971 v.1. J. PELLON PHOTOCHROMIC COMPO POLYMERIC BINDER Filed 06%. 27, 1967 IRRAD/A T/O/V TIME L 06 SEED/V0.5
INVENTOR. JOSEPH JAG/N70 PELLO/V ATTORNEY United States Patent O 3,565,814 PHOTOCHROMIC COMPOSITIONS IN A LAURYL METHACRYLATE POLYMERIC BINDER Joseph Jacinto Pellon, New Canaan, Conn., assignor to American Cyanamid Company, Stamford, Conn., a corporation of Maine Filed Oct. 27, 1967, Ser. No. 678,591 Int. Cl. G03c N72 US. Cl. 252-300 3 Claims ABSTRACT OF THE DISCLOSURE Photochromic compositions comprising a polymer of lauryl methacrylate having dispersed throughout the body thereof various benzospiropyran compounds are described.
BACKGROUND OF THE INVENTION The instant invention resides in the field of photochromic compositions. It is more particularly directed to photochromic compositions comprising polymers of lauryl methacrylate which have dispersed throughout the body thereof various benzospiropyrans.
The incorporation of benzospiropyrans into polymeric matrices has been known in the prior artv For example, US. Pat. No. 3,212,898 discloses the use of such benzospiropyrans in polyester resins.
While the prior art systems have been found adequate for many service applications, they tend to suffer from the inability to change color very rapidly when subjected to ultraviolet or other light.
SUMMARY I have now found that the sensitivity of benzospiropyran photochromic compositions, i.e., their rate of color change per unit of exposure, can be materially and drastically increased by incorporating them into a polymer of lauryl methacrylate rather than other polymer systems. The re sultant compositions are more easily and rapidly activated in service and therefore enable applications to which they are subjected to be more economically conducted. They are useful in all areas wherein known systems are used, such as data display, signal processing, information storage, photographic dodging, automobile Windshields, eyeglass lenses, containers, memory devices, such as optical analogue computers, temporary oscillographs, light switches, optical masks, jewelry, toys, advertising articles and the like.
BRIEF DESCRIPTION OF THE DRAWING The accompanying drawing is a graphic representation showing the change in optical density at 555 III/.4 of a composition comprising poly(lauryl methacrylate) and 3% of 1',3,3' trimethyl 6 nitro8'-meth0xy-spiro(2H-1- benzopyran-2,2'-indolene), represented by the open circle and a second composition comprising poly(methyl methacrylate) and 7% of the same spiropyran compound represented by a closed circle (9). Both compositions are in the form of unsupported films, the lauryl film being 1.0 mil thick and the methyl film being 0.7 mil thick. As can be readily seen the poly(lauryl methacrylate) film reaches a higher change in optical density than the poly (methyl methacrylate) film in a shorter irradiation time. Both curves were plotted by recording the optical density change of the two compositions produced in Example 1, below.
3,565,814 Patented Feb. 23, 1971 DESCRIPTION OF THE INVENTION INCLUDING PREFERRED EMBODIMENTS The benzospiropyran compounds which are useful as the photochromic additives of the present invention are well known in the prior art and have the general formula:
wherein R, R and R represent the same or different alkyl radicals having 1 to 20 carbon atoms, inclusive, and R and R taken together form a saturated carbocyclic ring, R is hydrogen or an alkyl radical having 1 to 20 carbon atoms, inclusive, X, X X X Y, Y Y and Y represent hydrogen, an alkoxy radical having 1 to 4 carbon atoms, inclusive, a nitro radical or a halogen radical, and the individual pairs Y and Y Y and Y Y and Y X and X X and X or X and X when taken together, form a conjugated aromatic ring.
These compounds are well known in the art as are methods for their preparation. For example, US. Pats. Nos. 2,953,454 and 3,022,318 teach various compounds and methods for their preparation, while copending application, Ser. No. 239,334, filed Nov. 21, 1962, now abandoned by Cerreta et al., teaches others, said references hereby being incorporated herein by citation.
Examples of the compounds which correspond to Formula I include l,3 ,3 -trimethyl-5 ',6-dinitro-spiro (2H- 1 -benzopyran- 2,2'-indoline) 1,3,3-trimethyl-5',6-dinitro-8-rnethoxy-spiro(2H-1- benzopyran-2,2'-indoline) 1',3,3-trimethyl-5',8-dinitro-6-methoxy-spiro(ZH-lbenzopyran-2,2'-indoline), 1',3',3-tributyl-8-chlor0-6' butoxy-spiro(2H-l-benzopyran-2,2-indoline) 1-octyl-3-methyl-3-ethyl-3-propyl-4',7-diethoxyspiro (2H-1-benzopyran-2,2'-indoline), 1,3',3-tristearyl-3-butyl-S,6-benzo-6-fluoro-spiro(2H-lbenzopyran-2,2'-indoline), l,3',3'-trimethyl-6-nitro-6,7'-benzo-spiro(2H-l-benzopyran-2,2'-indoline), 1',3',3'-triethyl-7-bromo-4',7'-dimethoxy-spiro(2H-lbenzopyran-2,2-indoline), 1,3,3'-trimethyl-6-nitro-spiro(2H-1-benzopyran-2,2'-
indoline) l, 3 ',3 '-trimethyl-8-nitro-spiro (2H-1-benzopyran-2,2-
indoline) 1,3 ,3 -trimethyl-6-nitro-8-methoxy-spiro( 2H- l-benzopyran-2,2-indoline), l,3 ,3 -trimethyl-5-nitro-8-methoxy-spiro (2H- l-benzopyran-2,2-indo1ine 1', 3 ',3 -trimethyl-6-chloro-8-nitro-spiro(2H-1-benzopyran-2,2-indoline 1-methyl-3'-cyclohexyl-5,8-dichloro-5-methoxy-7'- iodo spiro(2H 1-benzopyran-2,2'-indoline) and the like.
The amount of photochromic material incorporated into the lauryl methacrylate polymer is not critical and depends generally upon the intensity of the color of the composition desired upon irradiation thereof, i.e., the more compound added, the greater the color intensity. However, an amount of photochromic material ranging from about 0.01% to about 20%, by weight, preferably about 0.05% to about 5.0%, by weight, based on the weight of the lauryl methacrylate being polymerized or lauryl methacrylate polymer, may be used.
The lauryl methacrylate may be used alone as a homopolymer or in conjunction with up to 50%, by weight, of a comonomer, such as those having the formula:
a (III) I C=CH wherein R is hydrogen or a lower alkyl radical having 1 to 4 carbon atoms, inclusive, and R is hydrogen, a lower alkyl radical having 1 to 4 carbon atoms, inclusive, or a halogen radical. Suitable monomers represented by this formula include styrene, methyl styrene, ethyl styrene, propyl styrene, butyl styrene, chloro styrene, bromo styrene, fiuoro styrene, iodo styrene, a-methyl styrene, a-ethyl styrene, a-butyl styrene, a-methyl methylstyrene, a-methyl ethylstyrene, lot-butyl ethylstyrene, u-ethyl chlorostyrene, vxpropyl iodostyrene and the like.
Examples of other applicable comomeric compounds which may be copolymerized with the lauryl methacrylate include the unsaturated alcohol esters, more particularly the allyl, methallyl, crotyl, l-chloroallyl, 2-chloroallyl, cinnamyl, vinyl, methvinyl, l-phenylallyl, butenyl, etc., esters of saturated and unsaturated aliphatic and aromatic monobasic and polybasic acids such, for instance, as acetic, propionic, butyric, valeric, caproic, crotonic, oxalic, malonic, succinic, glutaric, adipic, pimelic suberic, azelaic, sebasic, citraconic, mesaconic, itaconic, acetylene, dicarboxylic, aconitic, benzoic, phenylacetic, phthalic, terephthalic, benzoylphthalic, etc., acids; the saturated monohydric alcohol esters, e.g., the methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, amyl, etc.; esters of ethylenically unsaturated aliphatic monobasic and polybasic acids, illustrative examples of which appear above,'vinyl cyclic compounds (including monovinyl aromatic hydrcarbons), e.g., styrene, o-, m-, and p-chlorostyrenes, -bromostyrenes, -fluorostyrenes, -methylstyrenes, -ethylstyrenes, -cyanostyrenes, the various poly-substituted styrenes such for example, as the various di-, tri-, and tetra-chlorostyrenes, -bromostyrenes, -fluorostyrenes, -methylstyrenes, -ethylstyrenes, -cyanostyrenes, etc., vinyl naphthalene, vinylcyclohexane, vinyl furane, vinyl pyridine, vinyl dibenzofuran divinyl benzene, trivinyl benzene, allyl benzene, diallyl benzene, N-vinyl carbazole, the various allyl cyanostyrenes, the various alpha-substituted styrenes and alphasubstituted ring-substituted styrenes, e.g., alpha-methyl styrene, alpha-methyl-paramethyl styrene, etc.; unsaturated ethers, e.g., ethyl vinyl ether, diallyl ether, ethyl methallyl ether, etc.; unsaturated amides, for instance, N-allyl caprolactarn, acrylamide, and N-substituted acrylamides, e.g., N-methylol acrylamide, N-allyl acrylamide, N-methyl acrylamide, N-phenyl acrylamide, etc.; unsaturated ketones, e.g., methyl vinyl ketone, methyl allyl ketone, etc.; methylene malonic esters, e.g., methylene methyl malonate, etc.; ethylene; unsaturated polyhydric alcohol (e.g., butenediol, etc.) esters of saturated and unsaturated a'liphatic and aromatic, monobasic and polybasic acids.
Other exmples of monomers that can be copolymerized with lauryl methacrylate include the vinyl halides, more particularly vinyl fluoride, vinyl chloride, vinyl bromide and vinyl iodide, and the various vinylidene compounds, including the vinylidene halides, e.g., vinylidene chloride, vinylidene bromide, vinylidene fluoride and vinylidene iodide, other comonomers being added if needed in order to improve the compatibility and copolymerization characteristics of the mixed monomers.
Among the monomers which are preferred for use in carrying my invention into effect are, for example, compounds such as acrylonitrile, and other compounds, e.g., the various substituted acrylonitriles (e.g., methylacrylonitri-le, ethacrylonitrile, phenylacrylonitrile, etc.), the various N-substituted acrylamides and alkacryla-mides, for instance, N-dialkyl acrylamides and methacrylamides, e.g., N-dimethyl, -diethyl, -dipropyl, -dibutyl, etc., acrylamides and methacrylamides and the like.
The photochromic spiropyrans may be incorporated into the lauryl methacrylate polymer after the polymer is formed, by, for example, dissolving both components in a common solvent, or by adding the spiropyran during the polymer production.
The actual polymerization process employed during which the photochromic material may be completely and uniformly dispersed throughout the lauryl methacrylate polymer during polymerization is not critical, and generally any known process for the polymerization of the monomer may be employed. The exact process used in each instance is governed by the photochromic material which is to be incorporated into the resulting polymer. For example, a polymerization process should be selected which does not require the use of any material, substance, compound or condition which will neutralize or react with the photochromic material, thereby nullifying the reversible color change ability of the photochromic compound. In other words, if any material in a predominant excess, such as an acid catalyst or other functional compound, or a chain length regulator such as a mercaptan, is a necessary ingredient of the polymerization process, that process cannot be used to produce the compositions of the present invention, since spiropyrans are sensitive to these ingredients. The use of polymerization systems of this kind cause a decrease in the ability of the spiropyran to reverse its color.
The same is true of processes necessitating conditions of high temperature etc. wherein the organic spiropyran is destroyed. A polymerization method which may be used for example, comprises conducting the polymerization in the presence of a free-radical generating catalyst (and a polymerization regulator) at temperatures of from about 10 C. to C. Any known free-radical generating catalyst which initiates the polymerization of the lauryl methacrylate may be used. Suitable catalysts include, for example, the organic peroxides such as methyl ethyl ketone peroxide, benzoyl peroxide; the hydroperoxides such as cumene hydroperoxide; the persulfate type compounds such as potassium persulfate, or catalysts such as azobisisobutyronitrile and the like. Additionally, such catalysts as lauroyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, the dialkyl peroxides, e.g., diethyl peroxide, dipropyl peroxide, dilauryl peroxide, dioleyl peroxide, distearyl peroxide, di(tertiary-butyl)peroxide and di(tertiary-amyl) peroxide, such peroxides often being designated as ethyl, propyl, lauryl, oleyl, stearyl, tertiary-butyl and tertiary-amyl peroxides; the alkyl hydrogen peroxides, e.g., tertiary-butyl hydrogen peroxide (tertiary-butyl hydroperoxide), tertiary-amyl hydrogen peroxide (tertiarysolution of the polymer. The apparatus which simultaneously devolatilizes and extrudes the material comprises a chamber with one or more screws having a close tolerance with the wall for compounding the material in its passage therethrough, and at least one vacuum chamber amyl hydroperoxide), etc.; symmetrical diacyl peroxides, 5 for removing the volatile components of the mixture. for instance, peroxides which commonly are known under The terms photochromrc compoun d, photochromic such names as acetyl peroxide, propionyl peroxide, lauroyl t c of PhOtOChIOmlC material, as used In the peroxide, stearoyl peroxide, malonyl peroxide, succinyl stapt l c p n s, substances, of peroxide, phthaloyl peroxide, benzoyl peroxide, etc.; un- 10 terials which change their transmission or reflectance upon symmetrical or mixed diacyl peroxides, e.g., acetyl benzoyl being subjected to ultrav oletor VlSlblC irradlatlon and peroxide, propionyl benzoyl peroxide, etc.; terpene oxides, Subsequently revert to thelr Oflglhal Stat? PP sublechoh e.g., ascaridole, etc.; and salts of inorganic per-acids, e.g., thfifeof to a diihirent wavelength of Iadlatlbh, 0T removal ammonium persulfate, sodium persulfate, sodium per- 0f ihell'lltlal ra o carbonate, potassium percarbonate, sodium perborate, h COIIIPOSIUOHS 0f h lhyehhon y be fhrther potassium perborate, sodium perphosphate, potassium modified with such materials as fillers, dyes, lubricants, perphosphate, etc. Other examples of organic peroxide plasticizers, colorants, stabilizers, etc. It is also possible catalysts which may be employed are the following: t0 lengthen thfi hfe 0f the q p f y h lf tetralin hydroperoxide, tertiary-butyl diperphthalate, Various amounts of an ultraviolet light stablllzer into the tertiary-butyl perbenzoate, 2,4-dichlorobenzoyl peroxide, COIHPOSIUOIIS- h thls manhef the Photochfomlc hfelof the urea peroxide, caprylyl peroxide, p-chlorobenzoyl peroxadded behlosplfopyrahs 1S lbhgthehed y P q s an ide, 2,2-bis(tertiary-butylperoxy)butane, hydroxyhept l extraneous amount of ultrav olet light from commg into peroxide, the diperoxide of benzaldehyde and the ik contact with the photochromic material. When absorbers Catalyst concentrations ranging from 0.0001 to 5.00 parts, of thl$ p are added, amounts P to about 20%, by by weight, based on the weight of the monomer employed Welght, based'oll the W igh Of the polymer, may be used. may advantageously be used. The following examples are set forth for purposes of If emulsion polymerization processes are employed any illustration only and are not to be construed as limitations available emulsifier may be used, with compounds such on o instant l ventlon. All parts and percentages are as fatty acid soaps, rosin soaps, sodium lauryl sulfate, by Welght unless OtheFWlse speclfiednon-ionic emulsifiersd such las pglyethorlty alkylated pliitilnolsi EXAMPLE 1 compounds such as iocty so ium su osuccinate i exy sodium sulfosuccinate and the like, in amounts ranging To Sultable. vessel are added parts of Poly(lau.ryl from about1% 18%, by Weight preferably 4% to 5%, methacrylate) in toluene representing a solution having by weight based on the amount monomer employed an 18% solids content. To this solution are added 3 parts being exernplary of l,3',3'-trimethyl-6-nitro-8-meth0xy-spiro(ZH-l-benzo- The same limitations of procedure must also be placed The mlxture 1s stlried i the spiroupon the physical blending techniques when the photopyran is dissolved. The resultantsolutron is then drawn chromic material is blended with the lauryl methacrylate 2 g atplece 2 glasslald g i g temperature polymer utilizing various devices to admix the polymer or ours 0 pro a ml 16 and the photochmmic compounds 40 The resultant film 15 stripped from the glass substrate When physical blending of the polymer and photoand lrradlated W ml.wayelength of hght' The chromic substance is desired, known procedures such as l 9 m Optlcal density is recorded versus h utilizing a ball mill, a tumbler mixer, hot rolls, emulsion lgadlanon g g i curve i i blending techniques, Banbury mixers, Waring Blendors s 0 e on e rawmg an represente y e and the like are eifective. Another procedure which may 49 open i i be employed is known as a devolatilization-extrusion A 9" film (0] H111) of .poly'(methy1.niethacrylate) method wherein se arate streams of solutions of the contammg 7% of the Same Splropyran exhlblted a Slower d h t t 1 t dt optical density change after a longer irradiation time than I ymel' an P 0C flf P are 511 e 0 the lauryl methacrylate film under the same conditions of mg, compounding, devolati ization and extruslon 1n com- 50 exposure. The plot of the curve recorded testing the methyl mercially ava lable devices. In the devolatilizer-extruder, methacrylate film is Shown on the drawing by a closed the mlxture is worked in a chamber under heat and 1 vacuum so that new surfaces of the polymer mixture are Following th procedure of Example 1, various other contlnuously and rapldlybxposed to vacuum to remove spiropyran compounds represented by Formula I are inthe solvent befor e tr dl g P t. The t r corporated into various lauryl methacrylate polymers. In VolahhZatlOn as herein p yed refers to the step In each instance, the sensitivity is greater than in known which the nonpolymeric material is removed from the systems. The results are set forth in Table I, below:
TABLE I Polymer Benzopyran compound Cone. Percent Example 2 Lauryl methacrylate/methacrylic 1,3,3-trimethyl-G-nirto-spiro(2H-1- 1.0
acid (95/5) copolymer. benzopyran2,2-indollne). 3 Laurylmethacrylate/ethyl acrylate 1,3,3-trimethyl-fi-chl0ro-8-nitro-spiro(.ZH-l- 2.5
(95/5) copolymer. henzopyran-Q,2'-indoline). 4 Laurylmethacrylate/vinyl benzene 1,3,3-trimethyl-5,6-dinitro-S-methoxy-spiro- 0.50
(00/10) copolymer. (2 H-l-benzopyran-2,2-indoline). 5 Laurylmethacrylate/styrene/ 1,3,3-tributyl-6-nitro-6,7'-benzo-spiro(2H-1- 0.25
acrylonitrile (/15/10) terpolyrner. benzopyran-2,2indoline). 6 Poly(lauryl methacrylate) l,3,3-trimethyl-6-nitro-8-butoxy-spiro(2H-1 5.0
benzopyran-2,2-indoline) 7 Lauryl methacrylate/styrene (/20) 1,3,3-trime'thyl-5,6-dinitro-spiro(2H-1- 10.0
copolymer. benzopyran-2,2-indoline) 8 Lauryl methacrylate/acrylonitrile 1,3,3-trimethy1-5-iodo-spiro-(fl H-l-benzopyran- 4. 5
(50/50) copolymer. 2,2-indoline). 9 Polyflauryl methacrylate) 1,3.3-trimethyl-7-bromo-4,7-dimethoxy- 3.0
spiro (2H-1-b enzopyran-2,2-indoline) 10 Laurylmethacrylate/vmyl chloride 1,3' 3-trimethyl-5',P-dinitroG-ethoxy-spiro(2H- 1.5
wherein R, R and R individually represent an alkyl radical having from 1-4 carbon atoms, inclusive, R is hydrogen or an alkyl radical of 1-4 carbon atoms, inclusive, X, X X X Y, Y Y and Y represent hydrogen, an alkoxy radical of 1-4 carbon atoms, inclusive, a nitro radical or a halogen radical and the individual pairs Y 20 and Y Y and Y Y and Y X and X X and X or X and X when taken together, form a conjugated aromatic ring.
2. A composition according to claim 1 wherein said polymer is poly(laury1 methacrylate).
3. A composition according to claim 1 wherein said compound is 1,3,3-trimethyl-6-nitro-8-methoxy-spiro- (2H-l -benzopyran-2,2'-indoline) References Cited UNITED STATES PATENTS 3,212,898 10/ 1965 Cerreta 9690 3,329,502 7/1967 Ullman 9690 3,450,533 6/1969 Amidon et al. 96-90 NORMAN G. TORCHIN, Primary Examiner R. E. FICHTER, Assistant Examiner U.S. Cl. X.R. 969O