Abstract: Aqueous electroless nickel plating solutions comprising a water soluble nickel salt associated with a neutral zwitterion, e.g. alanine or glycine, and/or monovalent anion, e.g. lactate, nitrate, hypophosphite, acetate, sulfamate, hydrochloride, formate, propionate, trichloroacetate, trifluoroacetate, methanesulfonate, glycolate, aspartate or pyruvate, as counterion and chelant, a neutral, e.g. borate, or monovalent, e.g. hypophosphite, reducing agent, and a non-thiourea stabilizer, e.g. protonated dimethylamine or dimethylaminopropylamine or 2-hydroxyethanesulfonic acid. Valuable components of spent baths, e.g. nickel and neutral or monovalent anion species, can be advantageously recycled by employing solvent extraction and anion filtration operations.

Abstract: A foamed cellular cementitious composition useful for sound absorbing, thermal insulation and fire proofing is described. The cementitious composition is produced utilizing a mineral cement, an aggregate, water, and a stabilized foaming composition which includes at least one water-soluble film forming agent, and at least one foaming agent. The stabilized foaming composition provides air to the cementitious composition in an amount substantially in excess of that used in conventional air entrainment of cements. The film forming agent is preferably a resin emulsion and the foaming agent is preferably a nonionic surfactant, anionic surfactant or mixture thereof. The cementitious compositions have a density which is substantially lower than the density of a composition composed of mineral cement and aggregate per se.

Abstract: Starch-based biodegradable packaging fillers are provided which have high volumes, low weights, and excellent compressibility and resiliency properties. The products of the invention are fabricated by extrusion of a starch substrate, most preferably normal wheat starch, in the presence of minor amounts of a polyalkylene glycol or derivative thereof and/or a particulate bubble-nucleating agent. Effective biodegradable packaging fillers can thus be fabricated without the use of expensive modified starch substrates; however, such substrates can also be employed if desired, and the additives of the invention improve these products as well. In preferred production procedures, the additives are mixed with the starch substrate, and the mixture is preconditioned and then extruded through a twin screw extruder.

Abstract: Disclosed is a bimodal, insulative, styrenic polymer foam structure comprising a foam of a styrene polymer material of greater than 50 percent by weight of styrenic monomeric units, the foam having relatively larger primary cells with a cell size range of 0.05 to 1.2 millimeters and relatively smaller secondary cells ranging in cell size from about 5 percent to about 50 percent of the average cell size of the primary cells. The primary and secondary cells constitute at least about 90 percent of the total cell volume within the foam structure. The bimodal structure has an amount of carbon black sufficient to reduce the thermal conductivity of the structure below that of a corresponding bimodal structure without carbon black. Further disclosed is a process for making the foam structure.

Abstract: Starch-based biodegradable packaging fillers are provided which have high volumes, low weights, and excellent compressibility and resiliency properties. The products of the invention are fabricated by extrusion of a starch substrate, most preferably normal wheat starch, in the presence of minor amounts of a polyalkylene glycol or derivative thereof and/or a particulate bubble-nucleating agent. Effective biodegradable packaging fillers can thus be fabricated without the use of expensive modified starch substrates; however, such substrates can also be employed if desired, and the additives of the invention improve these products as well. In preferred production procedures, the additives are mixed with the starch substrate, and the mixture is preconditioned and then extruded through a twin screw extruder.

Abstract: An environmentally innocuous effective replacement for thiourea is disclosed for use as a complexing agent in displacement plating processes in which the plating solution is applied to the substrate surface to be plated by immersion or by spraying, cascading, pouring and the like. The replacement complexing agent is an imidazole-2-thione compound having the formula: ##STR1## wherein A and B are the same or different --R--Y groups, wherein R is linear, branched or cyclic alkenyl group containing 1 to 12 carbon atoms and Y is a hydrogen, halogen, cyano, vinyl, phenyl, or ether moiety. Of this class of compounds, 1-methyl-3-propyl-imidazole-2-thione is preferred for immersion tin plating. This class of complexing agents is particularly useful in spray displacement tin plating for the manufacture of printed circuit boards wherein free tin metal is added to the plating solution.

Abstract: Starch-based biodegradable packaging fillers are provided which have high volumes, low weights, and excellent compressibility and resiliency properties. The products of the invention are fabricted by extrusion of a starch substrate, most preferably normal wheat starch, in the presence of minor amounts of a polyalkylene glycol or derivative thereof and/or a particulate bubble-nucleating agent. Effective biodegradable packaging fillers can thus be fabricated without the use of expensive modified starch substrates; however, such substrates can also be employed if desired, and the additives of the invention improve these products as well. In preferred production procedures, the additives are mixed with the starch substrate, and the mixture is preconditioned and then extruded through a twin screw extruder.

Abstract: An electroless plating bath composition is produced by mixing stannous oxide, at least one member selected from the group consisting of lead oxide and lead perchlorate, perchloric acid, and thiourea. The composition thus obtained is ideal for electroless plating of a substrate of copper, particularly a substrate provided with a resist film.

Abstract: An acid solution for displacement plating of a reflowable tin lead alloy having a melting point not exceeding 500.degree. F. over a cupreous surface. The displacement plating solution contains stannous ions in an amount of from 0.05 to 0.50 moles per liter, plumbous ions in an amount of from 0.01 to 0.15 moles per liter, a total content of stannous ions and plumbous ions in an amount of from 0.05 to 0.60 moles per liter and a ratio of stannous ions to plumbous ions varying from about 1.0:3.0 to 50.0:1.0. The solution is characterized by an ability to plate the tin lead alloy at a plating rate of at least 100 microinches per 15 minutes. The deposit obtained is capable of reflow and is useful in the manufacture of printed circuit boards.

Abstract: A process for replenishing a tin-lead alloy displacement plating solution which comprises periodically adding complexing agent to the solution during use of the same to bring the total concentration of complexing agent to an amount sufficient to ensure adhesion of the deposit to its underlying substrate.

Abstract: The invention provides a bath for immersion plating a substance with a tin-lead alloy, which includes tin(II) ions, lead(II) ions, organic sulfo groups and thiourea or a mixture of thiourea and a thiourea derivative for a complexing agent. The organic sulfo groups allow insoluble thiourea complexes to be stably dissolved in the solution of the bath; thereby there is no need to retain the bath at a high temperature. Compared with conventional baths for immersion plating, the bath of the invention attains stable plating and a longer life of itself. Addition of the thiourea derivative prevents whiskers from being deposited and allows uniform and sufficiently smooth plating.

Abstract: Viscous aqueous electroless plating solutions comprising ionic depositable metal species such as copper or nickel, metal complexing agent such as EDTA, metal reducing agent such as formaldehyde or hypophosphite and thickener such as xantham gum, silica or carboxymethylcellulose have a viscosity greater than 50 cp, for instance up to 20,000 cp. The viscous solutions are useful for electrolessly depositing metal onto moving or inclined catalytic substrates and as a component of kits for applying electrolessly deposited metal images to such surfaces.

Abstract: A biodegradable shaped product comprising an expanded modified flour product preferably having at least 40% by weight amylose content and containing about 2% or more by weight of an inorganic water soluble salt, said expanded product having a low density, closed cell structure with good resilience and compressibility.Another embodiment provides a biodegradable packaging material comprising an expanded, low density, closed cell modified flour product, the flour preferably having at least 40% by weight amylose content and containing about 2% or more by weight of an inorganic water soluble salt, and the expanded product having a bulk density of less than about 2.0 lb/ft.sup.3, a resiliency of at least about 50%, and a compressibility of from about 100 to 800 g/cm.sup.2.

Abstract: The invention provides a bath composition for electroless solder plating comprising:(A) about 5 to about 120 g/l of at least one compound selected from the group consisting of alkanesulfonic acids and alkanolsulfonic acids,(B) about 10 to about 100 g/l of at least one compound selected from the group consisting of tin salts of alkanesulfonic acids and tin salts of alkanolsulfonic acids,(C) about 10 to about 100 g/l of at least one compound selected from the group consisting of lead salts of alkanesulfonic acids and lead salts of alkanolsulfonic acids,(D) about 10 to about 200 g/l of at least one compound selected from the group consisting of thiourea and thiourea derivatives, and(E) about 1 to about 250 g/l of at least one compound selected from the group consisting of monocarboxylic acids, dicarboxylic acids, tricarboxylic acids and salts thereof.

Abstract: A cellulose-derived sponge showing good flexibility even in a dried state is disclosed, which comprises a matrix of a cellulose having an open-cell structure. The sponge shows mechanical properties satisfying at least one of the following conditions (I) and (II):Y.ltoreq.0.07X.sup.3 +0.39X.sup.2 -0.04X+0.04 (I)Z.ltoreq.0.24X.sup.3 +1.17X.sup.2 -0.78X+0.08 (II)wherein X, Y and Z stand for the thickness (mm), the bending rigidity (gf cm.sup.2 /cm) and the hysteresis of bending moment (gf cm/cm), respectively, of the sponge having a bulk density of 0.8 g/cm.sup.3 or less and a water content of 25% by weight or less. The sponge may be prepared by mixing viscose, reinforcing fibers, salt cake, a foaming agent and an anionic polyelectrolyte with each other, and solidifying the mixture in a mold.

Abstract: An acid solution for displacement plating of a reflowable tin lead alloy having a melting point not exceeding 500.degree. F. over a cupreous surface. The displacement plating solution contains stannous ions in an amount of from 0.05 to 0.50 moles per liter, plumbous ions in an amount of from 0.01 to 0.15 moles per liter, a total content of stannous ions and plumbous ions in an amount of from 0.05 to 0.60 moles per liter and a ratio of stannous ions to plumbous ions varying from about 1.0:3.0 to 50.0:1.0. The solution is characterized by an ability to plate the tin lead alloy at a plating rate of at least 100 microinches per 15 minutes. The deposit obtained is capable of reflow and is useful in the manufacture of printed circuit boards.

Abstract: An electroless Pb-Sn alloy plating bath composition is obtained by mixing at least one of methane sulfonic acid, 1-hydroxyethane-1, 1-diphosphoric acid and a salt of 1-hydroxyethane-1, 1-diposphoric acid, compounds for forming Pb-Sn alloy and a reducing agent.

Abstract: Conformable marking sheet comprising a microporous thermoplastic polymer base sheet having a network of interconnected pores. The marking sheet has a low yield stress, making it conformable to rough surfaces. The pores of the base sheet can be filled with a diluent (wax) or they may have the diluent removed, for example by extraction. The construction may further comprise an adhesive on the bottom and a top marking indicium layer comprising a polymeric binder in which is partially embedded a multiplicity of retroflective lens elements, e.g., transparent microspheres.

Abstract: A process for removing, from spent electroless metal plating bath solutions, accumulated byproducts and counter-ions that have deleterious effects on plating. The solution, or a portion thereof, is passed through a selected cation exchange resin bed in hydrogen form, the resin selected from strong acid cation exchangers and combinations of intermediate acid cation exchangers with strong acid cation exchangers. Sodium and nickel ions are sorbed in the selected cation exchanger, with little removal of other constituents. The remaining solution is subjected to sulfate removal through precipitation of calcium sulfate hemihydrate using, sequentially, CaO and then CaCO.sub.3. Phosphite removal from the solution is accomplished by the addition of MgO to form magnesium phosphite trihydrate. The washed precipitates of these steps can be safely discarded in nontoxic land fills, or used in various chemical industries. Finally, any remaining solution can be concentrated, adjusted for pH, and be ready for reuse.

Abstract: Disclosed herein are a method for measuring the concentration of one or more ingredients in an electroless plating solution containing at least one metal ingredient, anions and a reducing agent, and concentration adjustment method and system making use of the method. The method features measurement of the concentration of the reducing agent after replacing the anions with anions of a different type which does not affect the measurement of the concentration of the reducing agent. The measurement of the concentration of the metal ingredient can be conducted by atomic absorption spectrometry or plasma spectro.metry, while that of the reducing agent can be performed by ultraviolet absorption spectroscopy or electrochemical quantitative analysis.

Abstract: A plastic foam material comprises an aggregate of discrete elements made of substantially individual cellulose fibers combined with a cellulose starch and including a plurality of bubbles produced by a gas-generating agent. The discrete elements are suspended in a matrix also including a plurality of bubbles produced by a gas-generating agent. In a preferred embodiment the matrix is also made of substantially individual cellulose fibers combined with a cellulose starch and formed into a geometric shape. In another preferred embodiment the discrete aggregate elements are substantially closed-cell foam and the matrix is substantially open-cell foam. In yet another preferred embodiment the discrete aggregate elements are substantially closed-cell, and the foam matrix is also substantially closed-cell.

Abstract: Compositions and method for applying a coating to a metallic surface characterized by the presence of tellurium and/or selenium.

Abstract: Novel heat resistant foams can be obtained by heating metal phosphonates or metal phosphonate precursors to temperatures of above 200.degree. C. They may for example be used as electrical and/or heat insulation materials, in the production of mouldings, as a cavity filler, as carriers for active ingredients and/or as fillers with low bulk densities.

Abstract: A biodegradable shaped product comprising an expanded high amylose starch product having at least 45% by weight amylose content, said expanded product having a low density, closed cell structure with good resilience and compressibility.Another embodiment provides a biodegradable packaging material comprising an expanded, low density, closed cell starch product, the starch having at least 45% by weight amylose content and the expanded product having a bulk density of less than about 2.0 lb/ft.sup.3, a resiliency of at least about 50%, and a compressibility of from about 100 to 800 g/cm.sup.2.

Abstract: Disclosed are an electroless copper plating solution comprising a copper ion, a copper ion-complexing agent, a reducing agent and a pH-adjusting agent, the plating solution comprising a trialkanolmonoamine or a salt thereof as a complexing agent and accelerator in an amount giving a higher copper deposition speed than the copper deposition speed obtained when the trialkanolmonoamine or salt thereof is present in an amount sufficient to complex the copper ion but not enough to function as the accelerator, and 1.2.times.10.sup.-4 to 1.2.times.10.sup.-3 mole/l of an iron ion compound as a reaction initiator and/or 1.92.times.10.sup.-4 to 1.92.times.10.sup.

Abstract: A biodegradable shaped product comprising an expanded high amylose starch product having at least 45% by weight amylose content, said expanded product having a low density, closed cell structure with good resilience and compressibility.Another embodiment provides a biodegradable packaging material comprising an expanded, low density, closed cell starch product, the starch having at least 45% by weight amylose content and the expanded product having a bulk density of less than about 2.0 lb/ft.sup.3, a resiliency of at least about 50%, and a compressibility of from about 100 to 800 g/cm.sup.2.

Abstract: An improved continuous, smooth, porous, rigid surface is supported by an array of shaped, porous, support blocks mounted on an impervious planar foundation and surrounded by bi-functional containment walls to form a gravity filtration and drainage apparatus. The particular shape of the support blocks in contact with the foundation creates a plurality of parallel flumes, the center-lines of which align with the slope, if any, of the plane to facilitate drainage to contiguous drainage ditches. Accessibility of these drainage flumes at both ends of the overall structure provide for inspection, flushing, and purging of the overlying filter surface to assure functionality by simplified maintenance procedures. The drainage apparatus can be attached to an impervious evaporation surface, on which residual solids harvested from the surface of the drainage apparatus are deposited and periodically manipulated for further accelerated dewatering by evaporation.

Abstract: Corrosion and wear resistant metallic compositions containing nickel, cobalt, boron and thallium and articles coated therewith are described. Preferred electroless coatings contain nickel and cobalt in a ratio of about 45:1 to about 4:1 and are deposited as hard, amorphous alloy nodules of high nickel content dispersed or rooted in a sofer alloy of high cobalt content. The coatings are preferably deposited on catalytically active substrates from an electroless coating bath containing nickel ions, cobalt ions, thallium ions, metal ion complexing agents and a borohydride reducing agent at pH about 12 to about 14. With post-coating heat treatment coated surfaces exhibit hardness levels as high as about 1300 Knoop.

Abstract: An aqueous foamable membrane-forming composition comprised of a water dispersible polymeric latex, preferably styrene-butadiene latex, and an alkyl ether sulfate surface active agent. The composition desirably contains a alcohol having 12 to 14 carbon atoms, an acrylic acid polymer viscosity modifying agent and powdered carbon. Compositions of the invention in dilute aqueous form can be foamed and deposited on a surface to be covered, such as a landfill. Upon standing, the foam develops into a substantially stable, weather resistent membrane.

Abstract: An aqueous autocatalytic electroless gold plating composition having improved stability and an excellent plating rate is provided which comprises about 0.002 to about 005M of a water-soluble alkali metal monovalent gold cyanide complex, about 0.01 to about 0.1M of a water-soluble cyanide compound, about 0.1 to about 1.0M of a carbonte compound, and about 0.01 to about 0.1M of a reducing agent selected from the group consisting of water soluble alkali metal borohydrides and water soluble amine boranes, the plating composition having a plating rate within the range of about 10 to about 14.

Abstract: A coating composition for providing a part with improved salt spray resistance, which includes undissolved solid hexavalent chromate in an aqueous acid solution which is the reaction product of phosphate ions with ions of the group consisting of chromate or molybdate ions, and their coatings and coated parts.

Abstract: An encapsulant composition comprising a lead zinc silicoborate glass which forms a crystalline phase of Zn.sub.2 SiO.sub.4 and ZnB.sub.2 O.sub.4 when it is fired at 650.degree.-800.degree. C.

Abstract: An expandable polymer concrete or mortar composition, and process for producing it, which allows the use of low temperature cure resins by incorporating a substituted mineral which is able to expand in the polymer concrete mix so that the dilation of the mineral will counteract the shrinking effect of the curing resin. The substituted mineral may be selected from the montmorillonite group and is produced by substituting its water of hydration with a higher volatility composition such as ammonia.

Abstract: A method of manufacturing a microporous thermally insulating body comprises mixing together a finely divided microporous insulating material such as silica aerogel or pyrogenic silica and a solid ammonia-generating compound in particulate form, and compressing the mixture to form a thermally insulating body. The ammonia-generating compound is dispersed evenly throughout the insulating material and may comprise, for example, ammonium carbonate, ammonium acetate or urea. Preferably, the ammonia-generating compound comprises a mixture of about one third by weight of ammonium carbonate and about two thirds by weight of ammonium bicarbonate together with a small proportion of magnesium oxide.

Abstract: A copper conductor composition having an improved solderability as well as a good adhesion, which comprises a copper powder, an inorganic binder and a boride or silicide of a metal such as W, Mo, Ti, Ta, Nb or Cr. The solderability is kept on a good level even if the composition is subjected to a firing operation repeatedly.

Abstract: A process and composition are disclosed for directly electrometallizing a non-conductive substrate such as the non conductive surfaces of a circuit board and to directly effect through hole plating and/or form circuits on the boards without employing an electroless metal coating.A process and composition is also described for depositing metals on a non-conductive substrate by using the reductive capacity of hydrogen in the presence of a metal catalyst on the substrate. The metal catalyst is combined with hydrogen that is generated electrolytically from a protic bath. The metal catalyst combined with hydrogen is contacted with a metal salt. The metal salt may be combined with the protic bath so that the hydrogen that is generated electrolytically combines with the metal catalyst and the metal salt is converted to a metal coating on the substrate.

Abstract: A coating composition for providing a part with improved salt spray resistance, which comprises undissolved solid hexavalent chromate in an aqueous acid solution which is the reaction product of phosphate ions with ions of the group consisting of chromate or molybdate ions, and their coatings and coated parts.

Abstract: A novel immersion tin composition is disclosed containing both thiourea compounds and urea compounds. A method for improving the adhesion of printed circuit boards to one another in a multilayer board and for minimizing or eliminating smear in a multilayer board is also disclosed comprising coating the metal layers of the individual circuit boards with an immersion tin coating prior to laminating them to form a multilayer board.

Abstract: A method of forming a temporary barrier between a substrate and the atmosphere by applying to the substrate a layer of foam generated from an aqueous composition comprising specified agents. Certain compositions especially adapted for this purpose are also provided.

Abstract: A biodegradable packaging material comprising an expanded high amylose starch product having at least 45% by weight amylose content, said expanded product having a low density, closed cell structure with good resilience and compressibility.Another embodiment provides a method of preparing a low density, biodegradable packaging material comprising extruding a starch having at least 45% by weight amylose content, in the presence of a total moisture content of 21% or less by weight, at a temperature of from 150.degree. to 250.degree. C.

Abstract: A novel devitrifying frit is disclosed which has a coefficient of expansion essentially the same as that of silicon. The subject frits have a high softening temperature and excellent reheat stability which make them useful in ink formulations for forming dielectric layers in multilayer circuitry. The frits are also suitable for use as a substrate material for direct mounting of silicon chips or for use in thick film via-fill inks.

Abstract: The bath uses nickel-II-tri(ethylenediamine) hydroxide and/or cobalt-II-tri(ethylenediamine) hydroxide having the formula M(NH.sub.2 --C.sub.2 H.sub.4 --NH.sub.2).sub.3 (OH).sub.2 as a source of the metal to be deposited, where M represents nickel and/or cobalt, and where the ethylenediamine acts as the complexing agent.

Abstract: A ferrophosphorous composition with improved conductivity and passivation resistance in prepared by treating ferrophosphorus particles with an aqueous solution containing a dilute mineral acid and ions of chromium and metal selected from the group consisting of zinc, strontium, calcium, barium, lead or copper. In a preferred embodiment, the concentration of chromium and zinc ions in the solution is in the range of about 2 grams/liter to about 10 grams/liter, and the treatment time is from about 2 to about 6 minutes.The treated ferrophosphorous particles can be formulated in a suitable resin binder for use as corrosion resistant coatings, weldable coatings, EMI shielding coatings or electrically conductive coatings. The treated ferrophosphorus particles can also be used in powder metallurgy applications.

Abstract: Disclosed is a medical tube comprising a mono-layer medical tube comprising a high molecular weight compound, wherein the inner texture of a tube wall constituting the tube is porous and no skin layer is present on the inner face of the tube wall.The porous inner texture of the tube is microscopically spongy and contains cells or voids interconnected by pores. The inner wall of the tube contains concavities which open into the cells or voids and communicates them with any fluid flowing through the tube.

Abstract: This invention relates to a metallizing composition capable of forming an electroconductive coating of satisfactory adherence properties on the surface of a sintered ceramic article, particularly on a sintered silicon nitride type ceramic article. The metallizing composition contains metal salts of tungstic acid and/or molybdic acid and a metal of Group IVb of the Periodic Table of Elements or a compound thereof. The electroconductive coating of high adherence properties is formed by applying the metallizing composition on a sintered ceramic article and drying the deposited layer of the composition in air, heating the dried layer, and firing the layer in a non-oxidizing atmosphere. The metallizing composition is suitable for the formation of the electroconductive coating on a complexly shaped sintered ceramic article such as, for example, on the inner surface of a hollow ceramic article.

Abstract: A novel immersion tin composition is disclosed containing both thiourea compounds and urea compounds. A method for improving the adhesion of printed circuit boards to one another in a multilayer board and for minimizing or eliminating smear in a multilayer board is also disclosed comprising coating the metal layers of the individual circuit boards with an immersion tin coating prior to laminating them to form a multilayer board. The immersion tin composition may also be prepared from a two component system which eliminates or substantially retards the formation of H.sub.2 S in the presence of sulfur containing components.

Abstract: A process for producing an inorganic foam includes mixing a metallic compound, such as aluminum and/or magnesium nitrate, into a slurry with an acid or acidic solution, such as acid phosphate solution, and then heating the slurry to a predetermined temperature for a sufficient length of time to decompose the metallic compound to the metallic oxide. After the decomposition, reaction can occur between the metallic oxide and the acid or acidic solution to produce a strong binding medium for the foam. As formation, and consequently hardening, of the binding medium cannot commence until after the heating stage, hardening of the binding medium can be controlled to prevent premature hardening before the binding medium is applied to its working environment.

Abstract: Disclosed is a metallizing composition comprising an oxynitride glass of the Mg-Al-Si system and/or the Y-Al-Si system and a powder of a high-melting-point metal. This composition has a good affinity with a nitride ceramic material and a carbide ceramic material and is useful for forming metallized layers on substrates of these ceramic materials.

Abstract: Metallized polymer compositions are disclosed, the surface of which comprises an intermetallic compound of a metal element A (Sn, As, Sb or Bi) and a metal element B (Fe, Co, Ni, Cu, Zn, Ga, Ru, Rh, Pd, Ag, Cd or In), preferably an intermetallic compound of antimony and a metal element B. Processes for producing such metallized polymer compositions involve either the reduction of a metal element A compound in the presence of metallic metal element B and the polymer or the compression of a laminate of metal element A and metal element B layers onto the polymer. The metallized polymers are useful in the production of printing circuit boards, electromagnetic interference shielding devices, membrane switches, capacitors, conductive fibers, magnetic tapes and disc, antistatic mats, barrier polymers and optical storage devices.

Abstract: The invention concerns a collagen sponge which has a denaturation temperature of at least 37.degree. C., is not cross-linked and in one of its two embodiments forms an optically clear solution in aqueous medium. As compared with the collagen sponges previously known, it is particularly suitable as support material for pharmaceutical and cosmetic active substances since it has a higher denaturation temperature than the latter and dissolves again in contact with body fluid. The collagen sponge of the invention is prepared from an optically clear collagen solution by precipitation with neutral salts, dissolving and reprecipitation and then subjecting the collagen to freeze-drying without removal of the precipitation salt. Acid-swollen collagens and/or cellulose or cellulose derivatives can also be added to the solution, whereby the physical properties of the collagen sponge can be affected.