Abstract: The present invention relates to surface-modified pigments based on platelet-shaped substrates, having improved settling and reagitation characteristics, and to their preparation processes and use.

Abstract: A description is given of coated inorganic pigments comprising an organic pigment which has a coating, prepared by the sol-gel process from glass-forming components and densified to form a xerogel or glass, having a layer thickness of at least 0.8 .mu.m. These pigments are prepared by spray drying a sol-pigment dispersion, followed if desired by thermal densification of the xerogel layer to form a glass layer. The coated pigments are suitable for producing enamels and moldings.

Abstract: Abrasive grain with increased projectability in a UP deposition process is provided with a first conductive coating and a second coating comprising a silicon-containing compound.

Abstract: The present invention is neutral-aged hydrophobic silica gels having a reduced surface area and a method for their preparation. The method comprises three steps, where in the first step a mixture comprising a silica hydrosol and colloidal silica is contacted with a strong mineral acid at a pH less than about 1 to form a silica hydrogel having incorporated therein colloidal silica. In the second step the silica hydrogel is aged at a pH within a range of about pH 3.5 to pH 8. In the third step the silica hydrogel is contacted with an organosilicon compound in the presence of a catalytic amount of a strong acid to effect hydrophobing of the silica hydrogel to form a hydrophobic silica hydrogel having a surface area within a range of about 100 m.sup.2 /g to 450 m.sup.2 /g in the dry state. In a preferred method the hydrophobic silica hydrogel and is further contacted with a sufficient quantity of a water-immiscible organic solvent to convert the hydrophobic silica hydrogel into a hydrophobic silica organogel.

Abstract: A non-chrome process for the pretreatment of substrate surfaces to simultaneously clean them and improve their bonding strength for organic coatings such as adhesives, protective primers, sealants, paints, composites and similar materials conventionally bonded to such substrates, including non-chromated or chromated curable organic resin protective coatings applied directly to bare aluminum substrates. The invention involves the use of novel wipe solvent compositions containing a major volume of an environmentally-safe volatile organic solvent which has a low composite vapor pressure or is otherwise exempt from federal, state or local regulations, and a minor volume of a polyfunctional coupling agent, preferably of the silane type.

Abstract: An anhydrous zinc antimonate sol comprising a surface-modified anhydrous zinc antimonate colloid particles dispersed in a liquid, the surface-modified anhydrous zinc antimonate colloid particles comprising anhydrous zinc antimonate colloid particles as nuclei and a silicon-containing substance coating surfaces of the colloid particles, the sol containing an amine and/or an hydroxycarboxylic acid and a method for producing the same. The anhydrous zinc antimonate sol of the present invention is useful as transparent antistatic materials for resins, plastics, glasses, paper, and magnetic tapes, etc., transparent ultraviolet absorbents, transparent heat wave absorbents, high refractive index hard coating agents, antireflective agents, and the like.

Abstract: A system is disclosed for inhibiting the corrosion of ferrous and other metals by passivating the metals. The system includes novel buffered compositions which may be applied to metal products, and novel combinations thereof with metals, for preventing or retarding corrosion, as well as methods for applying the buffered compositions to metal products, such that corrosion protection of the products is achieved. The methods include an in-situ application to existing structures with metal reinforcement as well as applications to metal products during manufacture. Generally, the compositions may be in various forms and comprise one or more layers, at least one of which includes a water repellent but water vapor permeable carrier component and one or more pH buffer components. The buffer is selected to produce a passivating pH at the surface of the metal.

Abstract: A process which comprises maintaining a mixture of carbon dioxide, surface treating agent and colorant at a temperature of from about -10.degree. C. to about 200.degree. C., and optionally removing carbon dioxide.

Abstract: The invention relates to a display screen having a phosphor layer of a phosphor composition of a phosphor coated with an oxygen compound of one of the elements magnesium, calcium, barium, zinc and aluminium, and with colloidal SiO.sub.2 having an average particle size of 70 nm.ltoreq.d.ltoreq.130 nm. The invention further relates to a phosphor composition of a phosphor coated with an oxygen compound of one of the elements magnesium, calcium, barium, zinc and aluminium, and with colloidal SiO.sub.2 having an average particle size of 70.ltoreq.d.ltoreq.130 nm, and to a method of manufacturing the phosphor composition.

Abstract: A display screen having a phosphor coating comprising a phosphor composition of a phosphor provided with a coating which comprises one or more oxgyen compounds of the elements zinc, aluminium, magnesium, calcium and barium as well as colloidal SiO.sub. particles, said colloidal SiO.sub.2 particles being composed of SiO.sub.2 particles having an average size of 4 nm.ltoreq.d.ltoreq.30 nm, corresponding to a specific surface of 100 m.sup.2 /g.ltoreq.A.sub.s .ltoreq.550 nm m.sup.2 /g, and SiO.sub.2 particles having an average size of 50 nm.ltoreq.d.ltoreq.150 nm, corresponding to a specific surface of 25 m.sup.2 /g.ltoreq.A.sub.s .ltoreq.70 m.sup.2 /g.

Abstract: A process for preparing silicon granules with a chlorine contamination below 50 ppm by weight by deposition of elemental silicon on silicon particles in a fluidized-bed reactor. This reaction has a heating zone below a reaction zone. The silicon particles, in the heating zone, are fluidized by means of an inert silicon-free carrier gas to produce a fluidized bed and are heated by means of microwave energy. The silicon particles are reacted within the reaction zone, a reaction gas made up of a silicon source gas and the carrier gas. The average temperature of the reaction gas in the reaction zone, while the gas is perfusing the fluidized silicon particles, is maintained at less than 900.degree. C. The average temperature of the fluidized silicon particles in the reaction zone, while they are being perfused by the reaction gas, is maintained at greater than 900.degree. C.

Abstract: A coated ceramic powder comprises a plurality of ceramic particles and a siloxane star-graft coating polymer encapsulating at least a portion of the particles. The coating polymer comprises Si(w,x,y,z), where w, x, y and z are the mole percent tetrafunctional, trifunctional, difunctional and monofunctional monomeric units, respectively, and wherein w, x, y and z are about 45-75, 5-25, 5-45 and 5-10, respectively.

Abstract: Encapsulated electroluminescent phosphor particles and a method of making same. Each phosphor particle is encapsulated by a substantially transparent aluminum oxide-based multiple oxide coating. The encapsulated phosphors exhibit high initial luminescent brightness and high resistance to humidity-accelerated decay of luminescent brightness. The aluminum oxide-based coating provides reduced sensitivity to chemical degradation caused by exposure to condensed moisture or otherwise liquid water. The coating comprises the aluminum oxide and at least one other metal oxide.

Abstract: A method of making a ceramic retroreflective element having enhanced strength and increased retained reflectivity. The method of the present invention comprises forming retroreflective elements by the following steps:a) providing glass flakes;b) coating said glass flakes with a first barrier layer yielding coated glass flakes;c) providing optical elements;d) optionally coating said optical elements with a second barrier layer;e) blending said optical elements and said coated glass flakes;f) heating said optical elements and said coated glass flakes to spheroidize said flakes while agitating said optical elements and said coated glass flakes;g) further heating said optical elements and said spheroidized glass flakes to partially embed said optical elements in said spheroidized flakes while agitating said optical elements and said spheriodized flakes; andh) cooling said spheroidized flakes having partially embedded optical elements.

Abstract: This invention relates to a process for producing a selective absorber which contains one or more layers of a non-homogeneous material (cermet), the non-homogeneous material having been produced by means of a sol-gel process.

Abstract: A method of preparing an oral preparation, especially in the form of hard gelatin capsules, tablets or pellets, for use by the administration of drugs or supplementary nutrients for human beings or animals, said preparation on its outer side being provided with an enteric coating which contains or comprises a calcium salt of a polysaccharide. A moisture-resistant layer containing a protein, especially zein, can be provided between the material to be coated and the enteric coating. The enteric coating is formed in situ by spraying the liquid coating substances in a fluidized bed. The present invention also pertains to oral preparations which is prepared by the method.

Abstract: The disclosure describes a non-magnetic undercoating layer for a magnetic recording medium, coated on the surface of a non-magnetic substrate comprising:non-magnetic particles selected from the group consisting of particles (1) and (2):(1) coated acicular or spindle-shaped .alpha.-Fe.sub.2 O.sub.3 particles which are produced by adhering not less than 0.01 to 20 wt % (calculated as Al, SiO.sub.2 or Al and SiO.sub.2, and based on acicular or spindle-shaped .alpha.-Fe.sub.2 O.sub.3 particles as a core material) of an oxide or a hydroxide containing Al, Si or both Al and Si to the surfaces of acicular or spindle-shaped .alpha.-Fe.sub.2 O.sub.3 particles as a core material, and have a molecular weight-dependent parameter .alpha. represented by the following formula of not less than 0.5:As=K.sub.1 .multidot.M.sup..alpha.wherein M represents the number-average molecular weight of a binder resin, As represents the saturation adsorption of said binder resin, and K.sub.

Abstract: A process of manufacturing a porous carbon material and a capacitor having the same is provided. The process is comprised of: forming an intermediate blank (in the shape of a desired electrode) made of a metal carbide material having a porosity in the range of substantially 30% to 50% by volume. The blank is then impregnated by exposure to a gaseous hydrocarbon mixture at a temperature exceeding the decomposition of the hydrocarbon until the mass of the blank increases by about 10% to 25%. Next the inner surface of the blank is activated by heating. The blank is then exposed to gaseous chlorine and heated to remove the metal and form the blank having transport channels. Further chlorination occurs which forms nano sized pores in the structure. Thus, a porous carbon material is made which contains transport channels and nano sized pores.

Abstract: Disclosed are decorative surface coverings of the "inlaid" type having embossed patterns in register with inlaid patterns. Disclosed methods include the steps of: applying in a pattern on a first surface of a foamable layer an agent for modifying the foaming of said foamable layer to produce a foamable layer having a pattern of relatively nonfoamable areas and relatively foamable areas; applying a first collection of particulate resinous material substantially only to said areas containing said foaming modifier or only to said areas not containing said foaming modifier; and foaming said foamable layer in said relatively foamable areas.

Abstract: The present invention sets forth an enteric coating composition comprising a blend ofa) an alkali-soluble acrylic latex polymer andb) an aqueous solution of ammonium or alkaline salts of cellulose polymers.The invention also sets forth a method for preparing an enterically-coated dosage form and a method for preparing the present compositions.

Abstract: A dried gel material sterically entrapping nanoclusters of a catalytically active material and a process to make the material via an inverse micelle/sol-gel synthesis. A surfactant is mixed with an apolar solvent to form an inverse micelle solution. A salt of a catalytically active material, such as gold chloride, is added along with a silica gel precursor to the solution to form a mixture. To the mixture are then added a reducing agent for the purpose of reducing the gold in the gold chloride to atomic gold to form the nanoclusters and a condensing agent to form the gel which sterically entraps the nanoclusters. The nanoclusters are normally in the average size range of from 5-10 nm in diameter with a monodisperse size distribution.

Abstract: The present invention is neutral-aged hydrophobic organosilicate-modified silica gels and a method for their preparation. The method comprises three steps, where in the first step an organosilicate-modified silica hydrosol is contacted with a strong mineral acid at a pH less than about 1 to form an organosilicate-modified silica hydrogel. In the second step the organosilicate-modified silica hydrogel is aged at a pH within a range of about pH 3.5 to pH 8. In the third step the neutral-aged organosilicate-modified silica hydrogel is contacted with an organosilicon compound in the presence of a catalytic amount of a strong acid to effect hydrophobing of the organosilicate-modified silica hydrogel to form a hydrophobic organosilicate-modified silica hydrogel having a surface area within a range of about 100 m.sup.2 /g to 750 m.sup.2 /g in the dry state.

Abstract: A method for manufacture of a small dimension product using a dissolvable crystal. The crystal is coated with at least one layer of vacuum deposited material to form a coated crystal. The coated crystal is mixed with a liquid to dissolve the crystal and permit the layer of material to break into flakes. The flakes are separated from the liquid.

Abstract: The invention relates to a method of coating luminescent powders with a coating which comprises silicon dioxide, which method is characterized in that in a first step luminescent particles are dispersed in a solution containing one or more metallo-organic compounds of silicon and, optionally, metallo-organic compounds of further elements in a hydrous solvent mixture having a pH-value of 1<pH 5, whereafter the metallo-organic compounds are hydrolysed by adding ammonia. A further aspect of the invention relates to a luminescent powder having a coating composed of silicon oxide and at least one oxide of a further element selected from the group formed by aluminum, barium, lead, boron, magnesium, titanium, zinc, zirconium, cobalt, copper and iron.

Abstract: The present invention relates to compositions and methods for increasing the alertness of an individual through the administration of a stimulant such as xanthine or an xanthine derivative and preferably caffeine. A particular composition has one or more layers containing the stimulant arranged about the cores of microparticles. This allows the composition to release a significant portion of the stimulant within about two hours after administration so that a level of alertness can be readily achieved. Thereafter, the balance of the composition is released within about 6 to 10 hours, so that the stimulant can provide alertness during that time, but then can dissipate to levels which would not affect the individual's ability to sleep. Also, the formulation is carefully designed so that the stimulant does not accumulate in the individual's system.

Abstract: A process which comprises heating at a temperature of from about 31.degree. C. to about 200.degree. C. a mixture of supercritical carbon dioxide, metal or metal oxide, and a surface treating component, optionally removing carbon dioxide, and optionally cooling.

Abstract: Ultrafine iron-containing rutile type titanium dioxide particles useful for UV shielding cosmetics, pharmaceutical compositions and UV shielding paints are disclosed. They are rutile type crystalline titanium dioxide particles having an average single particle size of 0.01 to 0.1 .mu.m and containing an iron component at a concentration of 1 to 15% by weight as expressed as Fe based on the titanium dioxide in the crystalline structure. They can be produced by using a fine titania sol comprising rutile crystallites as basic particles, precipitating iron oxide or hydrated iron oxide onto the surfaces of the titania particles to effect coating, then firing and grinding.

Abstract: The present invention is hydrophobic silica gels and a method for their preparation under neutral conditions. The method comprises two steps, where in the first step the pH of a silica hydrosol is adjusted with a base to within a range of about pH 3 to pH 7 to facilitate formation of a silica hydrogel. In the second step the silica hydrogel is contacted with an organosilicon compound in the presence of a catalytic amount of a strong acid to effect hydrophobing of the silica hydrogel. In a preferred method, in a third step the hydrophobic silica gel is contacted with a sufficient quantity of a water-immiscible organic solvent to convert the hydrophobic silica hydrogel into a hydrophobic silica organogel.

Abstract: The present invention relates to compositions and methods for increasing the alertness of an individual through the administration of a stimulant such as xanthine or an xanthine derivative and preferably caffeine. A particular composition has one or more layers containing the stimulant arranged about the cores of microparticles. This allows the composition to release a significant portion of the stimulant within about two hours after administration so that a level of alertness can be readily achieved. Thereafter, the balance of the composition is released within about 6 to 10 hours, so that the stimulant can provide alertness during that time, but then can dissipate to levels which would not affect the individual's ability to sleep. Also, the formulation is carefully designed so that the stimulant does not accumulate in the individual's system.

Abstract: Organic peracids supported on inorganic macromolecular supports and a process for preparing them are provided. The peracids have general chemical formulae: Q--O--Si--A--NR--X--CO.sub.3 H (I) wherein Q represents the inorganic support, A is an alkylene or arylene group, R represents hydrogen, alkyl or an aryl group and X represents an optionally substituted alkylene or arylene group, or Q--O--Si--A--N X'--CO.sub.3 H (II) where Q and A are as defined above, and X' represents an optionally substituted alkylene or arylene group. The peracids have improved stability and recovery characteristics compared with those of the prior art.

Abstract: A method of fabricating artificial pearls by repeatedly dipping glass or plastic ball elements in a dye liquor and then heat-drying the dip-dyed ball elements at 50.degree.-60.degree. C. for about 15-20 minutes. The dye liquor contains 59 wt %-66 wt % ethyl solvent, 12 wt % acetone, 16.5 wt % cellulose acetate butyrate, 4.4 wt % pearl pigment, 0.55 wt % dye of desired base color, and 0.55 wt % essence.

Abstract: The invention relates to a muco-adherent, soluble device for administering active ingredients, a method of using said device, and an improved method of manufacturing said device using a continuous, enclosed mixing device capable of operating under pressure. The devices of the invention, which comprise a lyophilized foam and an active ingredient, have a dissolution time of at least about 8 hours, and preferably at least about 24 hours, and can provide for the sustained and/or controlled release of an active ingredient for up to about 24 hours.

Abstract: A method for coating pharmaceutical tablets is disclosed in which polymeric coating ingredients are combined with saccharides in a melt spinning operation to form composite particulates. The particulates are then dispersed in water to form an aqueous polymer coating solution, followed by application to pharmaceutical tablets by such methods as spray coating. The particulates dissolve extremely rapidly in water to form a dispersion of the polymer coating ingredients. Such rapid dissolution allows for increased processing rates and avoids disadvantages of the prior art such as the requirement of high sheer rate mixing for long times.

Abstract: The process comprises the steps of (A) mixing a base material (A-1), which is obtained by mixing an organopolysiloxane and a reinforcing silica and then heating the resulting mixture, with an aminosilane compound (A-2) represented by the formula:(R.sup.1).sub.n Si[N(R.sup.2).sub.2 ].sub.(4-n)wherein a plurality of R.sup.1 may be the same or different and are each a substituted or unsubstituted monovalent hydrocarbon group, a plurality of R.sup.2 may be the same or different and are each a substituted or unsubstituted monovalent hydrocarbon group, and n is 2 or 3; to allow them to react; and (B) heating the reaction mixture obtained in the step (A) under normal pressure or reduced pressure to remove an unreacted aminosilane compound and a by-product amine, contained in the reaction mixture.

Abstract: A soil top dressing is comprised of a mixture of sand, clay, a plasticizer material, water, and a coloring pigment, if desired. The components of the soil composition are preferably present in the following proportions by weight: sand 50-70%; clay 10-40%; plasticizer 0.5-5.0%; water 5-20%; coloring pigment 1-5%; all coated with kelp meal granules (5-20%). The method of making the invention involves continuously mixing a portion of the sand and the plasticizer in an agitation mixer. The sand becomes coated with the plasticizer, whereupon a quantity of clay is then added, followed by an additional portion of the plasticizing material. It is particularly important that the sand particles become coated with the plasticizing compound and clay. The coloring pigments are added and mixed thereafter. The foregoing particles are thereupon coated with particles of kelp meal. As soon as complete mixing takes place, material can be immediately transferred from the mixer to suitable packaging.

Abstract: Oxidation resistant coatings on carbon fibers are provided. Oxidation inhibitor particles are incorporated into a polymeric sizing coating on carbon fibers to protect the fibers from deterioration and erosion due to oxidation of carbon.

Abstract: The present invention relates to a method for producing a microgranulated particle having particle size of not more than 0.2 mm, wherein a fine powder with the average particle size of not more than 10 .mu.m, which is being agitated, tumbled or fluidized, is granulated, with a solution containing a binder alone or a binder and a surfactant being sprayed onto the surface thereof. The present invention allows to produce pharmaceutical preparations for poorly soluble and poorly absorbable drugs and preparations requiring a high content of the active ingredient. Also, it can provide an easy-to-handle powdery microgranulated particle in the field of food and fertilizers.

Abstract: Silicon oxide-coated solid particles are produced by decomposing silanes which contain at least one alkanoyloxy radical with water vapor and/or oxygen in the presence of the agitated solid particles.

Abstract: Pharmacologically inactive spherical seed cores comprising at least 50% by weight of microcrystalline cellulose having an average degree of polymerization of 60 to 375, wherein the spherical seed cores have an average particle size of 100 to 1000 .mu.m, a tapped bulk density of at least 0.65 g/ml, an aspect ratio of at least 0.7, a water absorption capacity of 0.5 to 1.5 ml/g, and a friability of no more than 1%; spherical granules comprising the spherical seed cores coated with a powdery layer comprising active ingredients and having an outer layer of coating provided on the powdery layer; and a process for the production of spherical granules, comprising the steps of coating the spherical seed cores with powder comprising active ingredients using an aqueous binding solution, spraying an aqueous solution or suspension of a coating agent thereon, and drying the resulting coated granules.

Abstract: The present invention relates to the application of ceramic coatings on substrates. The method comprises applying a preceramic coating comprising hydrogen silsesquioxane resin, a material containing Si--Si bonds which forms volatile SiH compounds, and a catalyst followed by pyrolyzing the preceramic coating in an inert atmosphere. The novel ceramic coatings formed by the process of this invention are especially valuable on electronic devices.

Abstract: A microencapsulated pharmaceutical is formed by vapor depositing a polymeric film about an active pharmaceutical agent. The film thickness of the vapor deposited film is controlled to provide effective controlled release of said pharmaceutical agent subsequent to application. In a preferred embodiment the pharmaceutical is an orally ingestible pharmaceutical formed by vapor deposition of a poly-p-xylylene polymer about a core comprising an active pharmaceutical agent. The pharmaceutical agent exhibits surprising controlled release activity inspite of the extreme inertness of vapor deposited films such as Parylene films.

Abstract: A process for preparing silane metal oxides comprising reacting a metal oxide with an amine compound to form an amine metal oxide intermediate, and subsequently reacting said intermediate with a halosilane.

Abstract: A granular material which includes an inorganic substrate has a ceramic coating which substantially reduces dust generation during processing of the granular material. The ceramic coating comprises the reaction product of an alkali metal silicate and an aluminosilicate, the ceramic coating further including a magnesium complex and an alkali metal chloride. The magnesium complex and alkali metal chloride are dispersed within the coating. It has been found that the use of magnesium chloride alone eliminates the use of oil in preventing dusting of the resultant granule material. Methods of producing such ceramic-coated granular materials are also disclosed, as well as methods of reducing dust generation using magnesium chloride.

Abstract: The present invention provides a pigment-attached blue-emitting phosphor having attached a blue pigment which has fastness and chemical stability and is excellent in reflection spectrum characteristics, and a color cathode-ray tube having a blue-emitting fluorescent layer containing the blue pigment formed on the inner surface of a face plate.The present invention also provides a pigment-attached blue-emitting phosphor having a CoO.ZnO.SiO.sub.2 type blue pigment attached thereto, and a color cathode-ray tube provided with a blue-emitting fluorescent layer containing the blue pigment particles on the inner surface of a face plate.

Abstract: A method of inhibiting algae growth on an asphalt shingle surface exposed to varying humidity using a blend of copper-containing algae-resistant granules and non-algae-resistant granules. The copper-containing algae-resistant granules comprise a substrate granule having at least one inner ceramic coating layer comprising cuprous oxide and a seal coating having a thickness covering the inner layer and which is at time t.sub.o devoid of copper.

Abstract: A method of making synthetic color pigments comprises synthesizing monodispersed colloidal core particles by precipitation from a solution and applying dye material to the core particles either by adsorption directly into the core particles or by adsorption or incorporation into alumina fixation shells at the surfaces of the core particles. Additional functional shells may be applied to the dyed core particles for various reasons. The pigments are useful for the coloration of various media such as printing inks and paint compositions.

Abstract: A cathode-ray tube phosphor is manufactured by coating, on the surfaces of phosphor particles, a mixture of a metal alginate containing at least one type of a metal selected from the group consisting of Zn, Al, and an alkali earth metal and at least one type of a water-soluble binder selected from the group consisting of gum arabic, gelatin, polymethacrylamide, and polyvinyl alcohol.

Abstract: Provided is an improved process for removing hydrogen sulfide from fluid streams by contacting hydrogen sulfide contaminated fluid streams with a novel composition comprising zinc oxide and a diatomite material coated with a colloidal oxide. Additionally, a novel method for producing a composition comprising the steps of coating a diatomite material with a colloidal oxide solution followed by mixing the thus coated diatomite material with zinc oxide to form a paste is further provided.

Abstract: A structural article for high temperature applications comprises a body formed of at least partially consolidated, particulate silicon nitride, a conformal outer coating of silicon nitride or silicon carbide on the body, and a conformal intermediate layer of a silicon, oxygen and nitrogen-containing compound, i.e. silicon oxynitride, chemically bonded to both the body and the outer coating. The method for making such an article comprises providing a body formed of at least partially consolidated, particulate silicon nitride, oxidizing the surface of the body, removing silicon dioxide from the oxidized surface of the body; and chemically vapor depositing a conformal outer coating of silicon nitride or silicon carbide. The conformal outer coating provides a protective envelope around and assists in high temperature isostatic pressing of the body and hence permits one to use the structural article in isostatic pressing processes.

Abstract: Coated pharmaceutical dosage forms which are resistant to gastric juice and release their active ingredient rapidly at a predetermined pH value in the range from pH 5 to pH 8 are obtained in accordance with the invention by coating pharmaceutical dosage forms with an aqueous dispersion containing dispersed latex particles of a first polymer which contains carboxyl groups and is water soluble between pH 5 and pH 8 and of a second water insoluble film forming polymer, in a weight ratio between 60:40 and 5:95.