Abstract: The invention relates to the production of transparent electric conductors.According to the invention, a doped tin oxide layer formed by CVD is heat-treated to improve its conductivity.

Abstract: This disclosure is directed to a heat reflective glazing including a glass sheet having two generally planar parallel surfaces or sides with a multilayer coating on one of the side, and a method of producing such glazing. The side of the glass sheet having the multilayer coating thereon is designated as the film or coated side while the other side is designated as the glass side of the glass sheet. The multilayer coating comprises a first silicon-containing coating formed directly on the glass surface, a titanium nitride-containing coating overlying the first coating, a second silicon-containing coating covering the titanium nitride-containing coating, and an optional abrasion resistant coating, e.g., comprising tin oxide, on the second silicon-containing coating. The process for producing the coatings is a chemical vapor deposition process preferably carried out during the production of glass by the float process.

Abstract: Disclosed is a method of manufacturing a preform for an asymmetric optical fiber which comprises the steps of (a) fixing plural transparent glass rods involving at least one core-mother rod functioning as the core in said optical fiber in parallel relationship, (b) depositing glass soot around an assembly of said plural parallel fixed glass rods, thereby providing a single porous cladding bearing the predetermined shape, and (c) vitrifying the porous cladding by thermal fusion, thereby providing the entirely integral transparent preform. The above method does not involve any process of perforating a drilled-pore which is needed inevitably in conventional method. Therefore, it is possible to obtain a long preform with high dimensional precision, and to fabricate the optical fiber with low transmission loss.

Abstract: A thin-film optical interference filter designed and manufactured to have high transmission of blue light and high reflectance of infrared light. The novel feature of this filter rests in the thin-film layer design at the top and bottom of a quarterwave stack and the manufacturing technique by which this thin-film design is deposited. The thin-film layer design suppresses the so called halfwave holes which occur at wide angles of incidence of the incoming light. This desirable effect is achieved by the proper layer thickness and refractive index control in the manufacturing process.

Abstract: Process for the production of light microguides with low optical propagation losses by multilayer deposition comprises, deposited in this order on a substrate, a first layer of index n, a second guide layer of index n+.DELTA.n.sub.1 and a third layer covering the two first-mentioned layers and of index n+.DELTA.n.sub.2. The second guide layer is deposited in two successive stages comprising: a first deposition stage followed by a partial etching of a first intermediate layer through an appropriate mask, in such a way that the unmasked part of the first intermediate layer has a thickness, counted from the interface located between the first layer and the first intermediate layer, equal to h, and a second deposition stage of a second intermediate layer of a material having the same index n+.DELTA.n.sub.1 as the preceding intermediate layer and surmounting the latter by a height h'.

Abstract: A preform for fabrication of a glass fiber optical transmission line is prepared by chemical reaction of vapor ingredients within a glass tube. Reaction, which may be between chlorides or hydrides of, for example, silicon and germanium with oxygen, occurs preferentially within a constantly traversing hot zone. Flow rates and temperature are sufficient to result in glass formation in the form of particulate matter on the inner surface of the tube. The particulate matter deposits on the tube and is fused with each passage of the hot zone. Continuous rotation of the tube during processing permits attainment of higher temperatures within the heated zone without distortion of the tube.

Abstract: A method for fabricating an alignment layer on a substrate of a liquid crystal display device which includes aligning the center line of the substrate such that it lies substantially along a line that passes through the center of and perpendicular to a linear source. The substrate is then rotated about its center line to a desired angle, and the source material is vacuum deposited onto the substrate.

Abstract: A transparent article comprising on the surface of a transparent substrate a cured transparent coating film composed of a composition comprising 100 parts by weight of an organic silicon compound represented by the following general formula (I) and/or a hydrolysis product thereof:R.sup.1.sub.a R.sup.2.sub.b Si(OR.sup.3).sub.4-a-b (I)wherein R.sup.1 and R.sup.2 each stand for an alkyl group, an alkenyl group, an aryl group or a hydrocarbon group having a halogen group, an epoxy group, a glycidoxy group, an amino group, a mercapto group, a methacryloxy group or a cyano group, R.sup.3 stands for an alkyl group having 1 to 8 carbon atoms, an alkoxyalkyl group, an acyl group or a phenyl group, and a and b are 0 or 1,10 to 300 parts by weight of a polyfunctional epoxy resin having an aromatic ring and/or an aliphatic ring and 25 to 800 parts by weight of antimony oxide fine particles having an average particle size of 1 to 200 m.mu..

Abstract: An optical recording medium using a recording layer of an alloy taking two different crystalline states exhibiting different reflectivities is preferably manufactured by depositing a plurality of layers, each of which consists essentially of an element or an intermetallic compound, i.e. a material having a lower crystallizable temperature, to form a recording layer having a desired average chemical composition, while heating a substrate on which the recording layer is being deposited.

Abstract: A method of treating a substrate having first and second sides with corresponding oppositely facing first and second surfaces, to produce curvature in the first surface. The method includes the steps of removing material, according to a predetermined pattern, from the second side of the substrate, and applying a stress-producing film of material to at least one surface of the substrate to thereby cause the substrate to bend to produce the desired curvature in the first surface.

Abstract: The invention relates to a transparent glass board for use in document copying machines as the copying glass on which each sheet of original documents is placed and, in the case of copying machines of automatic document feed type, is forced to slide. To ensure good copying and smooth sliding carriage of original paper sheets, a transparent antistatic coating layer using tin oxide and/or indium oxide is formed on one or each of the top and back surfaces of a transparent glass, and a transparent lubricative coating layer using an organic silicon compound having isocyanate groups attached to Si atom is formed on the top side of the glass plate so as to provide a top surface with which each sheet of documents comes into contact. The antistatic layer has a thickness of 300-1500 .ANG. and the lubricative layer has a thickness of 300-2000 .ANG..

Abstract: In a method for creating a corrosion-resistant coating (27) of high reflectivity on the surface of a workpiece (22), especially a glass reflector insert, in an evacuable coating chamber with a vaporizing system disposed therein, a second coating (24) of aluminum is deposited cold from a vapor onto a first, cold-applied coating (23) forming an adhesion mediator of nickel-chromium oxide, and onto that a third coating (25) of SiO.sub.2 is applied cold, and a fourth coating (26) of TiO.sub.2 or Ta.sub.2 O.sub.5 is applied at a workpiece temperature of at least 250.degree. C., and finally, as a fifth coating (27), a nickel-chromium oxide layer is deposited reactively from a vapor at a workpiece temperature of at least 250.degree. C. The deposit of the first, third, fourth and fifth coatings (23, 25, 26, 27) from a vapor is performed by means of electron beam vaporizers and the vapor depositing of the second coating (24) is performed by means of a resistance vaporizer.

Abstract: Optical components (16), particularly germanium components, are provided with a coating on exposed surface (15) within a vacuum chamber (17) by production of a glow discharge plasma containing carbon and another depositable element from feedstock gases which are fed to the chamber (17) via mass-glow rate controllers (9, 10, 11). The mass flow rate of the feedstock gases is maintained substantially constant at predetermined levels during respective time intervals to provide a multilayer coating of predetermined characteristics. Typically the coating has at least one first layer which is amorphous hydrogenated germanium carbide, at least one second layer which is amorphous hydrogenated germanium and at least one third layer which is amorphous hydrogenated carbon, these layers being ordered such that each second layer is bounded on each side by a first layer and the third layer is bounded on one side by a first layer, the other side of the third layer forming the exposed surface of the coating.

Abstract: An optical coating which is stable upon sustained exposure to water vapor is provided by a low-temperature photochemical vapor deposition process. First, there are provided a first vapor phase reactant containing silicon, a second selected vapor phase reactant, and an oxygen-containing precursor which are capable of interacting upon radiation inducement to form the corresponding oxides of the vapor phase reactants. A chosen substrate is exposed to the first and second selected vapor phase reactants in predetermined proportions and the chosen oxygen-containing precursor in the presence of radiation of a predetermined wavelength to induce a reaction to form a coating on the substrate. The coating comprises silicon dioxides containing a predetermined proportion of the second oxide, such as lead oxide. The coating maintains stable optical properties upon sustained exposure to water vapor. Graded index optical elements as well as quarterwave stack structure may be formed by this process.

Abstract: A method for fabricating graded refractive index (rugate, optical filters as well as complex rugate filters having prespecified refractive index verses thickness profiles is disclosed. A plurality of at least two different compatable thin film deposition source components of different refractive index, which are stoichiometrically combinable in variable proportion, such as silicon nitride and silicon oxide, or zinc sulfide and zinc selenide, are used to form a thin film material with a refractive index which varies as a function of the proportions of the components. Each source component is separately laser flash evaporated and codeposited on a substrate to form a coating while monitoring the physical and optical thicknesses of the coating, to allow adjustment of the respective laser flash evaporation rates of the source components.

Abstract: Disclosed is a method of manufacturing a preform for an asymmetric optical fiber which comprises the steps of (a) fixing plural transparent glass rods involving at least one core-mother rod functioning as the core in said optical fiber in parallel relationship, (b) depositing glass soot around an assembly of said plural parallel fixed glass rods, thereby providing a single porous cladding bearing the predetermined shape, and (c) vitrifying the porous cladding by thermal fusion, thereby providing the entirely integral transparent preform. The above method does not involve any process of perforating a drilled-pore which is needed inevitably in conventional method. Therefore, it is possible to obtain a long preform with high dimensional precision, and to fabricate the optical fiber with low transmission loss.

Abstract: Coatings, which act as barrier layers to inhibit migration of alkali metal ions from a glass surface and/or act as color suppressing underlayers for overlying infra-red reflecting or electrically conducting layers, are deposited by pyrolysis of a gaseous mixture of a silane, an unsaturated hydrocarbon and carbon dioxide on a hot glass surface at a temperature of 600.degree. C. to 750.degree. C.

Abstract: A micro-optical building block system for optical processing of light signals and method for making the components used in the system. The basic system includes a master substrate on which is mounted at least one building block. Typically, there are a multiplicity of pre-defined positions at which the building blocks will mate with the master substrate. Building blocks can be positioned adjacent to each other on the master substrate in such a way as to allow light signals to be transferred between them. Mating relief patterns are formed on both the master substrate and the building block substrates, the relief pattern areas on the master substrate being adjacent and repetitive, or alternatively, different patterns. The mating relief patterns enable self alignment of the building blocks at predetermined positions on the master substrate. The relief pattern on the building blocks is adapted to be employed to embody a variety of optical components as integral or constituent parts of the relief pattern.

Abstract: Optical conductors, useful in the transmission of data-encoding light beams, that comprise an optically transmissive rod carrying one or more cavities, each with a border defining an inclined planar surface, can be produced via a method comprising the steps of (1) coating the rod, via plasma-assisted physical vapor deposition, with an amorphous material of lower refractive index than the rod's; and (2) rendering each inclined planar surface light-reflective. The sequence of steps (1) and (2) can be reversed.

Abstract: A method and composition for depositing SiO.sub.2 on substrates by chemical vapor deposition are provided wherein aminoxysilane reagents are utilized. These aminoxysilane reagents pyrolyze at about the same temperatures as organometallic reagents, permitting multiple alternating layers of silicon dioxide and metal oxides to be formed at the same operating temperature.

Abstract: Retroreflective materials are made by coating glass particles with both hydrophobic polymers and coupling agents or with siloxane compounds which have both hydrophobic side chains and coupling-type side chains capable of chemically bonding to, or of forming loose associations with, a wide variety of materials.

Abstract: A continuous, chemical vapor deposition method for producing a coated glass article is disclosed. A glass substrate is advanced continuously, while hot, past first and second treating stations. A non-oxidizing atmosphere is maintained in the vicinity of the first treating station, while an oxidizing atmosphere is maintained in the vicinity of the second station. A non-oxidizing gas which contains a silane, e.g., SiH.sub.4, is directed from the first treating station against a surface of the glass to form a silicon coating on that surface. An oxidizing gas which includes a metal compound in the vapor phase is directed from the second station against the silicon-coated surface of the article.

Abstract: The invention provides a novel silicone-coated, quartz glass-made optical fiber which is very advantageous in the high efficiency of the coating process as well as in the improved workability in the connecting works of the fiber terminals for extension of the communication lines by virtue of the excellent peelability of the coating layer from the surface of the quartz glass fiber even by mere drawing the coated fiber between fingers. The coating layer is formed of a radiation- or UV-cured silicone composition comprising (A-a) an organopolysiloxane having aliphatic unsaturation, e.g. vinyl, and/or (A-b) an organopolysiloxane having mercaptoalkyl groups, e.g. 3-mercaptopropyl groups, and (B) a curing accelerator.

Abstract: A novel process for producing a double refraction plate is disclosed. According to the process, a transparent dielectric material is directed to and deposited on a substrate from an oblique direction. Above all, for controlling the retardation of the resulting double refraction plate, a polarized light having a plane of polarization in a specific direction relative to the substrate is directed to the substrate through the variable phase plate and the light reflected from the substrate is observed through the variable phase plate, as the dielectric material is deposited from an oblique direction.

Abstract: A process for producing an aerosol stream, which is conducted through an essentially aerosol-free vapor and/or gas stream to prevent undesirable precipitation of particles contained in the aerosol stream, is augmented by additionally employing thermophoresis. For this purpose, the vapor and/or gas stream is heated to a temperature which is higher than the temperature of the aerosol stream. Thermophoresis then causes the particles to be held within the aerosol stream.

Abstract: An alkali silicate non-glare coating is disclosed which has improved optical properties, specially resistance to haze, as a result of acid treatment which removes excess alkali from the coating.

Abstract: Integrated optical waveguides, for example planar waveguides with stripes of guiding material formed integrally on a substrate, are manufactured by depositing the doped glass guiding material by plasma chemical vapor deposition. Several substrates can be arranged in a suitably shaped apparatus so that deposition can take place on all of them at once.

Abstract: This disclosure describes a novel method of coating a substrate, e.g., a transparent glass substrate, with a very thin inorganic coating of predetermined varying composition, e.g. an electrically-conductive tin oxide coating. The coating is carried out in such a way that quality control problems associated with leakage of the coating reactants from the reaction zone are virtually eliminated. The resulting coating can exhibit excellent non-iridescent properties even at thicknesses well below on micrometer.

Abstract: A method for producing a directed aerosol stream from gaseous and/or vapor phase reactants by conveying the gaseous and/or vapor phase reactants including vaporous silicon tetrachloride, water vapor, and at least one vaporous, fluorine-containing hydrocarbon to a reaction site; reacting the reactants at the reaction site in a flame-free chemical reaction to produce an aerosol composition constituted of solid silicon dioxide particles which include silicon dioxide doped with fluorine, whereby the optical index of refraction of the solid silicon dioxide particles is reduced; and causing the aerosol composition to flow as an aerosol stream from the reaction site and immediately surrounding the aerosol stream with a moving, essentially aerosol-free, gas and/or vapor stream to form a directed aerosol stream enveloped in the aerosol-free stream.

Abstract: An anti-reflection coating for an optical component and a method of forming the same are disclosed. The anti-reflection coating is formed on a substrate for an optical component by subjecting a mixture of an evaporating material and 10-30% of SiO.sub.2 to vacuum evaporation at room temperature without heating the substrate. When the anti-reflection coating is a single layer, a mixture of MgF.sub.2 and 10-30% of SiO.sub.2 is used as the evaporating material. When the anit-reflection coating is a multi-layer structure, a mixture of a fluoride or a silicon oxide and 10-30% of SiO.sub.2 for a first layer, and a mixture of a fluoride or an oxide and 10-30% of SiO.sub.2 for middle and last layers are used as the evaporating material.

Abstract: The present invention relates to a method for producing a directed aerosol stream by a flame free reaction which is conducted while enveloped within an aerosol free gas and/or vapor stream. It is particularly suitable for use in coating systems, as it permits economical coating without so-called wall deposits.

Abstract: A method for treating an alkali silicate non-glare coating with an acid in order to prevent alkali-induced haze is disclosed.

Abstract: A method of preparing an optical fiber includes the steps of applying a first cladding layer of a sinterable, glasseous particulate matter providing a selected index of refraction to a support surface, forming at least one longitudinally-extending groove in the layer prior to sintering, applying a deposit of glasseous particulate matter in said groove to ultimately define a core stripe having an index of refraction greater than that of the previously applied layer, applying a covering layer of glasseous particulate matter, sintering the various layers and the core strip to provide an optical fiber preform, and drawing the preform to provide an optical fiber having a rotationally non-symmetric characteristics with a core of higher index of refraction than the surrounding cladding.

Abstract: A method for adhering silver to a glass substrate for producing mirrors includes attaining a silicon enriched substrate surface by reducing the oxygen therein in a vacuum and then vacuum depositing a silver layer onto the silicon enriched surface. The silicon enrichment can be attained by electron beam bombardment, ion beam bombardment, or neutral beam bombardment. It can also be attained by depositing a metal, such as aluminum, on the substrate surface, allowing the metal to oxidize by pulling oxygen from the substrate surface, thereby leaving a silicon enriched surface, and then etching or eroding the metal oxide layer away to expose the silicon enriched surface. Ultraviolet rays can be used to maintain dangling silicon bonds on the enriched surface until covalent bonding with the silver can occur. This disclosure also includes encapsulated mirrors with diffusion layers built therein. One of these mirrors is assembled on a polymer substrate.

Abstract: A process for depositing on the surface of a substrate a layer of a chosen material having continuous gradations in refractive index in a predetermined periodic pattern. The substrate is exposed to two vapor phase reactants which react upon radiation-inducement to produce the chosen material, and the relative proportion of the reactants is varied in a predetermined and continuous sequence to produce continuous gradations in the stoichiometric composition and refractive index of the deposited layer as a function of thickness. Additionally, predetermined changes in refractive index and/or thickness across the horizontal surface of the substrate may be produced in combination with the change in refractive index as a function of thickness. Diffraction optical elements formed by such a process include various optical filters and reflective optical coatings.

Abstract: A process for making semi-reflective metallized glasses containing an anchoring layer, said anchoring layer being deposited by vacuum evaporation from an alloy comprising nickel in an amount of from about 40-70% by weight, chromium in an amount of from about 5-31% by weight, and molybdenum in an amount of from about 3-28% by weight. The anchoring layer may also be deposited from an alloy of nickel, chromium, molybdenum and at least one metal selected from the group of tungsten, iron and cobalt, in an amount of from about 55-75% by weight nickel, iron and cobalt, from about 5-31% by weight chromium, and from about 3-28% by weight molybdenum and tungsten. The anchoring layer is deposited upon the surface of a support glass by vacuum evaporation after which one or more layers may be deposited upon this anchoring layer.

Abstract: A method of providing a metal layer on a substrate having an ultra-smooth or microprofiled surface, in which the surface structure is reproduced in the metal layer. On the substrate surface which is hydrophilic or is made hydrophilic, preferably a monomolecular layer of alkoxysilylalkylthiol, an alkoxysilylalkylamine or a chlorosilylalkylthiol is provided as a bonding intermediary in a layer which is at most 15 molecules thick by contact with an atmosphere in which said substance is present in a vapor form. The metal layer is vapor-deposited thereon in a thickness of 50-300 nm.

Abstract: Reactive gases providing a coating on a substrate by CVD are made to meet in counterflow, in order to ensure, by the turbulence effect, that there is an almost instantaneous mixing of the said reagents. The movement of the gases before contact is ensured by two pipes containing baffles, the effect of which is to cause the gases to rotate in opposite directions to one another. Application to the coating of glass with transparent conductive SnO.sub.2.

Abstract: A reflector includes a base body exhibiting dielectric property at least at its surface. A reflecting layer made of aluminum is formed on one surface of the base body by vacuum deposition. A light-transmitting water-insoluble inorganic oxide layer is formed on the aluminum reflecting layer. The light-transmitting inorganic oxide layer has its micropores sealed by sealing agent comprising H.sub.2 O or a carboxylate of an iron family element having a low valence.

Abstract: A method of applying an intermediate bond coat on a laser mirror substrate is described comprising surface polishing the mirror substrate followed by depositing a layer of amorphous silicon, amorphous germanium, or mixtures thereof on the mirror surface, and polishing the thus coated mirror surface to a substantially void-free surface finish. Laser mirror substrates such as graphite fiber reinforced glass, molybdenum and silicon carbide coated by such process are also described.

Abstract: In a process of gaseous opalization a film of silica is formed by an oxidation reaction with a dry gas containing oxygen. Pure oxygen or oxygen diluted in an inert gas, other than nitrogen, may be used. An electric arc is generated by an alternating voltage between 5,000 and 10,000 volts and is directed at a chlorinated silicon compound, entrained by the dry gas containing oxygen, the feeding of which gas carrier does not form silica on the electrodes which generate the arc. This process may be applied to the opalization of incandescent and discharge bulbs of various sizes including tubes and globes of lighting apparatus.

Abstract: An inhomogeneous optical layer is formed on a surface of a substrate in a vacuum coater, in which the substrate is moved along a travelling path having path sections and a substance is evaporated from its source and deposited on the surface while the deposited substance is exposed to gas which is able to react on the substance. In such an operation, the deposition rate of the substance is varied monotonously along the path in each of the path section in order that, in a layer formed by the deposition on the substrate, the content of the substance and that of the reaction product are varied monotonously in the direction of thickness. If the refractive index of the substance is different from that of the reaction product, the resultant refractive index in the layer is varied monotonously in the direction of the thickness of the layer.

Abstract: An inhomogeneous optical layer is formed on a surface of a substrate in a vacuum coater, in which the substrate is moved along a travelling path having path sections and two substances are evaporated from their respective sources and both of the substances are deposited on a common surface section of the surface. In such an operation, the deposition rate of each of the substances is varied monotoneously along the path in each of the path section in order that, in a layer formed by the deposition on the substrate, the content of each of the substances is varied monotonously in the direction of thickness. If the refractive index of one of the substances is different from that of the other of the substances, the resultant refractive index in the layer is varied monotoneously in the direction of the thickness of the layer.

Abstract: A fluid crystal display cell (1) which has 2 cell plates coated with electrodes (14, 15) which include a fluid crystal mass (5). The first cell plate (1) is transparent and the second cell plate (2) is equipped with an adhesive cell interior reflector layer (9), at least in some regions, which contain the flake-like aluminum particles (6) as reflector particles and a bonding phase for this. The bonding phase is a practically homogeneous, transparent layered mineral matrix (7), consisting almost primarily of SiO.sub.2, in which the aluminum particles (6) are imbedded.

Abstract: A method of repairing an intermediate amorphous silicon and/or germanium bond coat on a laser mirror substrate is described. The initial coating is put down by polishing the mirror substrate followed by depositing a layer of amorphous silicon, amorphous germanium, or mixtures thereof on the mirror surface, and polishing the thus coated mirror surface to a substantially void-free surface finish. A layer of oxide of silicon or germanium is deposited on the thus formed coating either during, after, or in sandwich fashion during the formation of such intermediate bond coat. The intermediate coating can be surface polished back to the original amorphous layer or the oxide can remain on the surface after polishing.

Abstract: An improved process for chemical vapor deposition of coatings of the type bearing silicon oxide or silicon oxide/tin oxide mixtures. The process involves the use of mono- or di-alkoxy terminated permethylpolysilanes, preferably monomethoxypentamethyldisilane, as a silicon-donating reactant. Also disclosed are novel transparent silicon-bearing coating compositions which can be formed by the improved process to have any desired refractive index value from about 1.44 to about 2.0.

Abstract: Optical waveguide circuits, such as signal splitters, can be produced by etching grooves in a transparent, glass substrate and by filling the grooves with glass having a higher refractive index than the material of the substrate. The grooves have a semicircular cross-section and the filling glass is produced by a low temperature plasma-activated chemical vapor deposition process. Two substrates can be placed on top of each other, with the surfaces in which the filled grooves have been provided in contact, to form an integrated optical circuit.

Abstract: Glass bulbs are given a deposit of silica by oxidation of silane with oxygen on the inside of the bulb. The silica deposit is formed by oxidation, with oxygen through an electric arc, of silane diluted to a slight concentration of 0.1 to 3% by volume in a gas inert in regard to silane. The process applies to opalizing, i.e. providing a light diffusing layer, incandescent and discharge bulbs of different sizes, including tubes, and globes of lighting fixtures.

Abstract: A lamp envelope comprised of silica glass having a SiO.sub.2 --B.sub.2 O.sub.3 glass layer on an inner surface thereof is coated on the free surface of such SiO.sub.2 --B.sub.2 O.sub.3 glass layer with a protective layer comprised of a silica glass having a lower B.sub.2 O.sub.3 amount relative to the B.sub.2 O.sub.3 amount in the SiO.sub.2 --B.sub.2 O.sub.3 glass layer.

Abstract: A surface coating composition comprising:(A) 100 parts by weight of a partially hydrolyzed condensation product of alkyltrialkoxysilane having the general formulaR.sup.1 Si(OR.sup.2).sub.3in which R.sup.1 represents an aliphatic hydrocarbon group of C.sub.1 -C.sub.4 or an aromatic hydrocarbon group, and R.sup.2 represents an aliphatic hydrocarbon group of C.sub.1 -C.sub.4 ;(B) 10-100 parts by weight of an organic carboxylic acid of C.sub.1 -C.sub.5 ; and(C) 0.01-1.0 part by weight of an anionic surface active agent containing a fluorocarbon chain.