Abstract: Method and apparatus for cleaning a gas for preventing the contamination of a surface of a substrate in a localized space are disclosed. A photocatalyst is provided in a selected area of the localized space and the photocatalyst, as it is illuminated with light, is contacted by the gas to be treated, whereby any noxious gases are removed from the treated gas. Alternatively, a unit apparatus composed of an ultraviolet radiation source, a photocatalyst, a photoelectron emitter and an electrode is installed in a selected area of the localized space and the gas to be treated is passed through the unit apparatus, whereby noxious gases and particulates are removed from the treated gas.

Abstract: An electronic air cleaner (10) includes a housing (20), a mechanical prefilter (30), an electrostatic precipitator cell (40) and at least one germicidal lamp (50). The electrostatic precipitator cell (40) includes a plurality of collector plates (42) for collecting thereon particulate material from the air stream. The germicidal lamp or lamps (50) are disposed to irradiate the collector plates (42) and any particulate material collected thereon with germicidal light to destroy microbial growth that might occur on the particulate material deposited on the collector plates. Reflectors (60) may be provided in operative association with the germicidal lamp or lamps (50) to concentrate the germicidal light unto the collecting surface of the collector plates (42). A post filter (90), disposed downstream with respect to air flow of the lamp or lamps (50), is provided to remove volatile organic compounds from the air flow.

Abstract: An exhaust emissions filtering system for filtering of particulate matter from a flow of exhaust. The exhaust emissions filtering system comprises an ultrasonic transducer unit, an ultraviolet light unit, a magnetic particle filter unit, and an electronic control unit. The exhaust emissions filtering system removes particulates from exhaust emissions by fracturing the particles with the ultrasonic transducer unit, further breaking down the fractured particles with a high-intensity ultraviolet light, and removing the particles with an electrostatic mesh that is located in the magnetic particle filter unit.

Abstract: A portable room air filter includes a rigid housing having an essentially-hollow reflective interior chamber. The interior chamber is bounded at one end by an air exhaust port, and by a removable HEPA filter element in fluid communication with an air intake port at an opposite, second end. The air purifier includes a germicidal ultraviolet light source mounted within the interior chamber, and a fan assembly draws air through the purifier. Baffling constructions prevent escape of ambient ultraviolet light, while ensuring free airflow through the purifier. Separate power switches control the fan assembly and ultraviolet light source. The purifier includes an interlock switch that disables the fan and ultraviolet light source when the purifier is opened. A status indicator provides visual feedback regarding the state of the ultraviolet light source. The purifier is lightweight and includes a grasping handle to facilitate movement of the purifier as needed.

Abstract: A method for disinfecting an airstream containing microorganisms by electrostatic precipitation by passing the airstream through the space between at least one grounded collection plate having at least one electrode spaced apart therefrom connected to a source of electrical potential, wherein the improvement comprises contacting the airstream with a photocatalyst having a predetermined band gap energy coated on the surface of each grounded collection plate and illuminated with photons having a wavelength corresponding to the band gap energy of the photocatalyst, so that at least a portion of the microorganisms that collect on the grounded collection plate are destroyed by photocatalytic oxidation. Devices embodying disinfecting methods are also disclosed.

Abstract: Air cleansing apparatus includes an electrostatic precipitator in which the collector plates are made of, for instance, reticulated chemical vapor deposited silicon carbide, or reticulated silicon carbide ceramic coated with titanium nitride, zirconium diboride, or chemical vapor deposited silicon carbide. Microorganisms entrained on the collector plates are thermally degraded or vaporized by microwave radiation directed against the plates during a sterilization period which follows a collection period.

Abstract: A process is provided for conditioning fly-ash present in flue gas which also contains sulfur dioxide and steam by subjecting the fly-ash containing flue gas to ultraviolet radiation so as to convert steam present in the flue gas into hydroxyl radicals which oxidizes about 5 to 10 percent of the sulfur dioxide in the flue gas into sulfur trioxide. This photo-produced sulfur trioxide conditions the fly-ash and renders it more easily separated in the electrostatic precipitator.

Abstract: An air purification system comprises a housing, a generally S-shaped duct mounted within the housing, at least one blower mounted within the housing for circulating air through the system, and purification structure for removing contaminants from the air. The system preferably comprises two blowers, a master control switch for activating one of the blowers to circulate air through the filter, and a secondary control switch for activating the other blower and the UVC source to initiate a UVC purification process to further purify the filtered air.

Abstract: An electronic air cleaner (10) includes a housing (20), a mechanical prefilter (30), an electrostatic precipitator cell (40) and at least one germicidal lamp (50). The electrostatic precipitator cell (40) includes a plurality of collector plates (42) for collecting thereon particulate material from the air stream. The germicidal lamp or lamps (50) are disposed to irradiating the collector plates (42) and any particulate material collected thereon with germicidal light to destroy microbial growth that might occur on the particulate material deposited on the collector plates. Reflectors (60) may be provided in operative association with the germicidal lamp or lamps (50) to concentrate the germicidal light unto the collecting surface of the collector plates (42).

Abstract: A lightweight portable germicidal air filter for home and personal use is disclosed. The air filter includes a cabinet which houses an electrostatic air filter, an ultraviolet lamp and a parabolic reflector or a convex lens for focusing the ultraviolet radiation emitted by the lamp on an upstream side of the air filter. The reflector or the lens are constantly oscillated to systematically sweep the upstream side of the filter with germicidal levels of radiation. A fan located adjacent the downstream side of the filter draws air through the filter and impels it out through areas for air outlet in the sidewalls of the cabinet. The advantage is a simple, lightweight germicidal air filter with few moving parts which is inexpensive to manufacture.

Abstract: Disclosed is a chemical and biological air purifier. The air purifier has a housing having an inlet and an outlet both aligned on a longitudinal axis, a turbulence generator, one or more vacuum ultraviolet (UV) sources achieving a chemical purification and one or more germicidal ultraviolet (UV) sources achieving the biological purification. The turbulence generator is mounted within the housing downstream of the inlet and promotes a dispersion and mixing of air received through the inlet. The vacuum UV source is mounted within the housing downstream of the turbulence generator and breaks oxygen molecules into mono-atomic oxygen which then reacts with chemical contaminants present in the air and degrades them by successive oxidation to odorless and inoffensive byproducts. The turbulence generator reduces the production of ozone by increasing the contact between the mono-atomic oxygen and the chemical contaminants.

Abstract: An integrated lamp air purification and cleansing system is disclosed which includes a lamp body which supports a lamp and contains an air purification system. The lamp body includes an air inlet for drawing in air and an air outlet for blowing out the air. An air purification system is enclosed in the lamp body for filtering and cleaning the air flow drawn in from the air inlet whereby the air flow blown out from the air outlet is filtered and purified. The air purification system includes an activated charcoal filter and an electrostatic filter for filtering particles from the air flow. The electrostatic filtering device further includes many elongated channels each surrounded by conductive channel walls which allow the air flow to pass through. Each of the elongated channels includes a discharging needle located in a center portion of the channel which induces an electrical discharge and ionization in the air flow passing through.

Abstract: An air purifier including a housing which has two air intake passages at two lateral sides and an induced-draft fan in an air accumulation chamber between the air intake passages, a plurality of air filters respectively mounted between the air accumulation chamber and the air intake passages, each air filter including two electrically insulative frames fastened together, and a plurality of metal wire gauze filters, and a high-voltage static electricity generator mounted inside the housing and connected to one metal wire gauze filter, the high-voltage static electricity generator providing high-voltage positive static electricity to one metal wire gauze filters, causing the other metal wire gauze filters to produce positive static electricity at one side and negative static electricity at an opposite side for catching dust from air passing through.

Abstract: A device for the removal of microscopic particles from air includes a tube which in a certain cross-section has a replaceable, suitably ionizing particle separation unit (4) with a multitude of threads or strips (10) which are held together in a common frame structure (11) extending across the tube. The strips (10) are arranged to be set in motion in relation to each other by the passing air, thereby generating static electricity for attracting micro particles from the air to the strips. The frame structure (11) is made of a flexible band formed into loops, the strips being affixed on the band, the frame structure also including a plurality of pipe- or tubeforming members located amongst the band loops, in order to distribute the air flow through the frame structure.

Abstract: The suction hood has an air depollution apparatus that is associated therewith and includes, inside a container that is connected to an intake grille in a downward region and to a discharge grille in an upward region, a mechanical filter, an activated-charcoal filter, suction fans that are adapted to produce a flow of air, and a collection device. The collection device includes, in succession: an electrification grid, which is supplied at a high voltage with negative polarity and is arranged on a horizontal plane that lies transversely to the container; a partition, which is arranged at an angle in front of the electrification grid so as to convey the stream of air toward at least one region that has a narrower cross-section; a negatively-charged deflector plate and a positively-charged collector plate that are arranged vertically so as to face each other at a short distance, so as to delimit the respective above- mentioned region having a narrower cross-section.

Abstract: A self contained air movement system for air purification and infection control includes an elongated upright enclosed housing including a base module, sidewalls, and an upper module. A fan intermediate the base module and the upper module draws unclean air from a room containing the system through the base module, then discharges a purified air stream from the upper module. The base module includes a downward facing air intake opening spaced from the floor. A pair of pre-filters are disposed on the base module in stacked relationship for trapping relatively large particulate matter from the entering air stream. The upper module includes a discharge grille opening to the environment with angled louvers for guiding and re-directing the purified air stream from a downstream HEPA-type filter into an inclined stream, flowing proximate to and along the ceiling of the room in which the system is located.

Abstract: The filter device for air purification has an electrification grid supplied with a high voltage of negative polarity and arranged on a plane transverse to an air flow for negatively charging particles present in the air. A partition is arranged at an angle in front of the electrification grid so as to convey the stream of air toward a narrower region. A negatively charged deflector plate and a positively charged collector plate, which face one another at a short distance, delimit a respective narrower region for respectively repelling and attracting the negatively charged particles. A germicidal lamp is arranged at an opening of the deflector plate and illuminates the collector plate substantially along its entire length in a direction which is transverse to the air flow.

Abstract: The present invention is directed to a method of removing aerosols using a radiation effect.

Abstract: In the process for investigating particles situated in a gas, a gas stream is guided past a miniaturized UV excimer radiator. In this case, the particles are ionized and subsequently filtered out, and the resultant photoelectrically induced current is measured. Since particles from different sources (petrol engine, diesel engine, cigarette smoke) exhibit a wavelength dependence which is characteristic of the source, by measurements at at least two wavelengths, which is readily possible when using UV excimer radiators with different gas fillings, pollutants can be detected according to the source.

Abstract: A germicidal air purifier for trapping and destroying airborne microorganisms is disclosed. The air purifier includes an ultraviolet radiation source and a juxtaposed filter medium. A one of the ultraviolet radiation source and the filter medium is fixed and the other is displaceable so that at least an upstream side of the filter medium is systematically exposed to germicidal levels of radiation. In a first preferred embodiment, a fixed ultraviolet lamp irradiates a cylindrical air filter which is rotated on its longitudinal axis in close proximity to the lamp so that the upstream side of the filter is systematically irradiated. In a second preferred embodiment, a radiant lamp fixture is moved reciprocally across an upstream side of a planar filter to systematically irradiate the filter. In a third preferred embodiment, a radiant lamp fixture is rotated about an axis which is orthogonal to its longitudinal midpoint so that a circular area of a planar filter is irradiated.

Abstract: In order to enhance the efficiency of charging in a friction charger, it is proposed to precharge the particles before the first collision with the walls by making use of the photoeffect. This is performed, preferably, through irradiating the particles using UV radiation from a UV excimer radiator.

Abstract: Sensitizers for photoconductive compositions and elements are disclosed. The sensitizers are 2,4,6 tri substituted pyrylium dye salts wherein at least one of said substituents is a 5 or 6 membered heterocyclic ring having at least one atom selected from the group consisting of N, O and S.

Abstract: Photoconductive insulating compositions comprising organic photoconductors are described. Organic photoconductor materials such as p-terphenyl or polyvinylcarbazole are dispersed or dissolved in an electrically insulating binder and chemically sensitized with a polymer having repeating units to which are appended a monovalent chlorendate radical. When employing the aforesaid polymeric chemical sensitizer, acrylic polymers or cellulose nitrates are especially useful as insulating binders for heterogeneous compositions of the subject type. Or, by omitting conventional binders, the described polymeric chemical sensitizer can function simultaneously as chemical sensitizer and insulating binder for such photoconductive compositions. Further, the present polymeric chemical sensitizer is particularly useful with one or more additional chemical sensitizers to yield sensitized compositions with especially desirable properties.

Abstract: A series of chelated diketones in which the chelated atom is aluminum can be used as acceptor type sensitizers and plasticizers for polymeric photoconductors of the donor type used in electrophotography.

Abstract: Electrostatic contrast control in p-type electrophotographic elements is achieved by incorporating into the photoconductive layer a hole trapping agent such as a tetraphenylboron anion, bromide ion, iodide ion, oxidizable dye such as a carbocyanine and dicarbocyanine, merocarbocyanine and merodicarbocyanine, styryl, oxonol, hemioxonol, or hemicyanine. Usable hole trapping agents have an oxidation potential in a neutral solution of at least 0.1 volts less than that of the photoconductor in the photoconductive layer.

Abstract: A dye-releasing mechanism is described which employs a nondiffusible dye-releasing compound having a dye or dye-precursor moiety attached thereto through a sulfonamido cleavage linkage so that a diffusible sulfonamide dye or dye-precursor will be released upon oxidation and subsequent alkaline hydrolysis of the compound.

Abstract: A photoconductive sensitive material composed of a conductive support and a layer consisting essentially of charge-generating pigment, trinitro-11H-indeno[1,2-b]quinoxaline-11-one and binder resin formed on said support, and a photoconductive sensitive material composed of a conductive support, a thin layer consisting of charge-generating pigment alone or mixed with binder resin and a layer consisting essentially of trinitro-11H-indeno[1,2-b]quinoxaline-11-one and binder resin, said two layers being formed in that order on said support, possess high sensitivity and always give a clear-cut image even when used repeatedly.

Abstract: A photosensitive member having at least two electrically operative layers is disclosed. The first layer comprises a photoconductive layer which is capable of photogenerating holes and injecting photogenerated holes into a contiguous charge transport layer. The charge transport layer comprises an electrically inactive organic resinous material containing from about 10 to about 75 percent by weight of: ##STR1## where R.sub.1 is selected from the group consisting of an alkyl with from 1 to 12 carbon atoms and an alkyl with from 1 to 12 carbon atoms substituted by aryl groups selected from the group consisting of phenyl, maphthyl, anthryl, and biphenyl and R.sub.2 is selected from the group consisting of methyl, ethyl, chloro, bromo and hydrogen.

Abstract: Photographic elements, processes for forming images in photographic elements and new compounds are disclosed. Generally, the invention relates to ballasted electron-accepting nucleophilic displacement compounds; after acceptance of at least one electron (reduction) by a nucleophile precursor group, the compounds are capable of undergoing intramolecular nucleophilic displacement to release a diffusible moiety, such as an image dye or a photographic reagent. In certain embodiments, the ballasted electron-accepting nucleophilic displacement compounds are used in combination with electron donors and electron-transfer agents. The processes disclosed are particularly useful in providing positive transfer images using negative-working silver halide emulsions.

Abstract: A method of spectrally sensitizing a photographic light-sensitive emulsion where a water-soluble solution, prepared by dissolving a methine dye having at least one water-soluble group in water in the presence of a "Red Shift Compound", as hereinafter defined, is added to a photographic light-sensitive emulsion to provide a photographic light-sensitive emulsion spectrally sensitized with increased sensitizing efficiency and with reduced fog. The disadvantages caused by the use of high organic solvent contents are avoided and photographic light-sensitive emulsions suitable for high-speed coating are obtained.

Abstract: The present invention provides 1,3,7-trinitrophenazine-5-oxide which has an excellent sensitization effect on organic photoconductors, as well as a photoconductive sensitive material comprising said compound and an organic photoconductor.

Abstract: Electrophotographic light-sensitive member carrying a layer on an electroconductive support, said layer comprising a charge generating substance, a binder and 7-nitro-2-aza-9-fluorenylidene-malonitrile.

Abstract: 3-(-FLUORENYLIDENE)CARBAZOLE DERIVATIVES, PROCESS FOR PREPARING SAME AND ELECTROPHOTOGRAPHIC LIGHT-SENSITIVE MATERIAL CONTAINING 3-(9-FLUORENYLIDENE)CARBAZOLE DERIVATIVES.

Abstract: Semiconductive compositions are produced by the inclusion of a particular class of dyes into a polymeric binder. When the binder is an organic photoconductive binder, the dyes act as exceptionally good sensitizers for the photoconductive material.

Abstract: 6,7,14,15-Tetrahydropyrido[2,1-b]pyrido[1',2':1,2]pyrimido[4,5-g]quinazolin e-7,15-dione is oxidized with a quinone as an oxidizing agent to produce 7,15-dihydropyrido[2,1-b]pyrido[1',2':1,2]pyrimido[4,5-g]quinazoline-7,15- dione.

Abstract: An organic photoconductive insulating composition and electrophotographic elements containing the same are prepared using as a photoconductor a polyarylalkane compound having the formula ##STR1## wherein R.sup.1 and R.sup.2 represent hydrogen, alkyl, or aryl groups, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 represent aryl groups, and A.sup.1 and A.sup.2 represent phenyl groups.

Abstract: Organic photoconductive materials comprising as an active ingredient a photoconductive copolymer consisting of 3 to 50 mole % of at least one acrylic monomer represented by the formula ##STR1## wherein R.sub.1 is hydrogen or methyl; and R.sub.2 is a group of the formula --C.sub.n H.sub.2n+1 or a group of the formula --CH.sub.2).sub.m X [wherein n is an integer of 0 to 18; m is an integer of 1 to 4; and X is a group of the formula --OR.sub.3 or ##STR2## (wherein R.sub.3 is a group of the formula --C.sub.l H.sub.2l+1 ; and l is an integer of 0 to 4)], and 97 to 50 mole % of a photoconductive monomer having an .alpha.,.beta.-unsaturated bond.

Abstract: A series of chelated diketones in which the chelated atom is boron can be used as acceptor type sensitizers for polymeric photoconductors of the donor type used in electrophotography.

Abstract: A process for preparing a photosensitive material for electrostatic photography having an improved memory resistance, which comprises a photoconductive layer on an electrically conductive substrate, the photoconductive layer comprising (1) a finely divided inorganic photoconductor, (2) 5 to 50 parts by weight, per 100 parts by weight of the photoconductor of an electrically insulating organic synthetic resin binder having a specific resistance of at least 10.sup.14 ohm-cm, and (3) 0.001 to 1 % by weight, based on the photoconductor, of at least one photo-memory erasing compound selected from alkali metal dichromates, which process comprises forming the photoconductive layer by applying a coating composition to the electrically conductive substrate at a coating weight of 5 to 50 g/m.sup.

Abstract: This invention relates to a method of making an electrophotographic imaging element, the resulting element, and the process of utilizing the element in electrophotographic processes. In its present form the element is generally of the known multi-layered type including a conductive substrate, a layer of charge generating photoconductive material, and a charge transport layer. The charge generating photoconductive layer requires no binder matrix and is comprised primarily of an organic dye material selected from organic primary amine soluble charge generating monoazo and disazo compounds and from organic primary amine soluble charge generating derivatives of squaric acid.

Abstract: Photoconductive insulating compositions in the form of organic photoconductive dispersions are described. Particles of organic photoconductor such as p-terphenyl are dispersed in cellulose nitrate and chemically sensitized with .pi.-deficient N-heteroaromatic compounds such as quinoxalines to provide useful heterogeneous photoconductive insulating dispersions. Such dispersions can be applied to an electrically conducting support to prepare electrophotographic elements.

Abstract: The invention is directed essentially to photographic material containing, on a carrier, a layer with azo dyestuffs of the formula ##STR1## wherein A, B, X and Y are certain substituents, in a second main aspect azo dyestuffs of the formula ##STR2## wherein B' represents certain substituents and in a third main aspect azo deystuffs of the formulaA.sub.1 --N.dbd.N--B.sub.1 --NH--CO--X.sub.1 --Y--Z.sub.1 --OC--HN--B.sub.1 --N.dbd.N--A.sub.1wherein A.sub.1, B.sub.1, X.sub.1, Z.sub.1 and Y are certain substituents.The photographic materials provide advantages stemming from the use of the dyestuffs of the invention which are distinguished by particularly high fastness to light coupled with excellent bleachability, good resistance to diffusion and advantageous color strength.

Abstract: A photosensitive member having at least two electrically operative layers is disclosed. The first layer comprises a photoconductive layer which is capable of photogenerating holes and injecting photogenerated holes into a contiguous charge transport layer. The charge transport layer comprises an electrically inactive organic resinous material containing from about 15 to about 75 percent by weight of N,N'-diphenyl-N,N'-bis(phenylmethyl)-[1,1'-biphenyl]-4,4'-diamine. The charge transport layer while substantially non-absorbing in the spectral region of intended use is "active" in that it allows injection of photogenerated holes from the photoconductive layer, and allows these holes to be transported through the charge transport layer. This structure may be imaged in the conventional xerographic mode which usually includes charging, exposure to light and development.

Abstract: A multi-active photoconductive insulating element having at least two layers comprising an aggregate photoconductive layer in electrical contact with a photoconductor containing layer.The aggregate photoconductive layer comprises at least one compound having the structure: ##STR1## wherein A represents: ##STR2## in which R.sub.1, R.sub.2, R.sub.3, and R.sub.4, which may be the same or different, represent a substituted or unsubstituted alkyl group having from 1 to 18 carbon atoms or a substituted or unsubstituted aryl group;R.sub.5 and R.sub.6, which may be the same or different, represent an electron withdrawing group, phenyl or substituted phenyl;R.sub.7 and R.sub.8, which may be the same or different represent an electron withdrawing group or hydrogen except that when Ar is unsubstituted phenylene or unsubstituted anthrylene, R.sub.7 and R.sub.8 must be other than hydrogen;R.sub.

Abstract: A photoconductive sensitive material composed of a conductive support and a photoconductive layer formed thereon, said photoconductive layer consisting essentially of charge generating pigment(s), 2,4,7-trinitrothioxanthone and resinous binder.

Abstract: A multi-active photoconductive insulating element is disclosed having at least two layers comprising an inorganic photoconductor-containing layer and an aggregate photoconductive layer. The aggregate photoconductive layer contains a continuous polymeric phase having dispersed therein a co-crystalline complex composed of (i) at least one polymer having an alkylidene diarylene group in a recurring unit and (ii) at least one pyrylium-type dye salt.

Abstract: A photoconductive insulating composition containing (a) one or more p-type organic photoconductor components and (b) a charge transfer complex of one or more electron acceptor components and one or more electron donor components, the electron donor components being selected from materials having one of the following formulas: ##STR1## wherein N REPRESENTS 0, 1 OR 2; X represents oxygen, sulfur, selenium or the groups >CR.sup.3 R.sup.4 or >C.dbd.CR.sup.5 R.sup.6 ; Y represents a single covalent chemical bond or the necessary carbon and hydrogen atoms to complete a 6 to 9 member saturated or unsaturated ring; and each of R.sup.1 through R.sup.8 represents a substituent group such that the resultant material forms a charge-transfer complex with 2,4,7-trinitro-9-fluorenone.

Abstract: Polyaryl hydrocarbon photoconductors having the formula ##STR1## wherein: N IS AN INTEGER HAVING A VALUE OF 0 OR 1;Ar.sup.1 and Ar.sup.2 each represents an aryl group including substituted aryl such as an aryl group that is fused to other aromatic or nonaromatic ring systems; R.sup.1, R.sup.2, R.sup.3 and R.sup.4 each represents a hydrogen atom, an alkyl group or an aryl group including substituted aryl and, when n is 1 and R.sup.1 and R.sup.4 are each hydrogen, R.sup.2 and R.sup.3 are each aryl; are combined with a sensitizer for the photoconductor and an electrically insulating binder to produce photoconductive compositions. Useful electrophotographic elements include a support having thereon such photoconductive insulating compositions.

Abstract: A photocurable electroconductive coating composition adapted to be crosslinked and insolubilized by actinic radiation comprises an acrylic monomer, a photoactivatable free radical polymerization initiator and a salt of a copolymerizable organic compound, wherein at least one of the monomers contains more than one polymerizable ethylenically unsaturated group. The cured coatings are insoluble in aqueous and organic solvents and are conductors of electricity suitable for conductive underlayers of photoconductive imaging elements and as antistatic coatings.

Abstract: Novel polymeric compounds having utility in multiactive photoconductive insulating elements. Such elements have at least two layers comprising an aggregate photoconductive layer in electrical contact with a photoconductor-containing layer.The aggregate photoconductive layer comprises at least one novel polymeric compound having the structure: ##STR1## WHEREIN R.sub.1, and R.sub.3, which may be the same or different, represent a substituted or unsubstituted alkyl group having from 1 to 18 carbon atoms or a substituted or unsubstituted aryl group;R.sub.2, and R.sub.4, which may be the same or different, represent an alkylene group having from 2 to 10 carbon atoms or a substituted or unsubstituted arylene group;R.sub.5 and R.sub.6 which may be the same or different, represent hydrogen or an electron withdrawing group;R.sub.