Patent GB-601956-A (GB)
Title: Improvements in the production of foam generating agents
IPC: A62D1/02
Filed: 1944-04-12
Abstract: Foam-generating agents are prepared by hydrolysing a sulphur-containing proteinaceous material selected from the class consisting of keratins, albumens, globulins and haemoglobins, in the presence of an aqueous non-acid solution having a pH value not greater than 10, by means of an oxide or hydroxide of a heavy metal selected from the group consisting of lead, zinc, cadmium, mercury, cobalt, nickel and copper.  The quantity of heavy metal oxide or hydroxide used is preferably in excess of that required to convert the sulphur in the proteinaceous material to the insoluble sulphide of the heavy metal.  The solution may then be filtered and any metal in solution derived from the hydrolysing agent removed and finally the solution is concentrated down to remove excess water.  In an example, dried blood is heated with water which may contain up to 0.025 mols. caustic soda, in the presence of litharge in a sealed autoclave at 105 DEG  to 110 DEG  C. for 24 hours, after which the contents are filtered, zinc dust added to precipitate dissolved lead and the solution again filtered and concentrated to a nitrogen content of 4.5 to 5 per cent.  The solution gives foams with air and fresh or salt water. Specification 517,767 is referred to.  The Specification as open to inspection under Sect. 91 is not limited to the use of the above-mentioned metallic oxides and hydroxides, but includes any having medium basic properties and an aqueous medium whose pH is above 10, for example, pH 11 may be employed.  It is stated that the metal in solution derived from the hydrolysing agent may be removed by precipitation by means of a finely divided metal which precedes it in the electro-chemical series.  This subject-matter does not appear in the Specification as accepted.ALSO:Foam-generating agents are prepared by hydrolysing a sulphur-containing proteinaceous material selected from the class consisting of keratins, albumens, globulins and h moglobins, in the presence of an aqueous non-acid solution having a pH value not greater than 10, by means of an oxide or hydroxide of a heavy metal selected from the group consisting of lead, zinc, cadmium, mercury, cobalt, nickel and copper.  The quantity of heavy metal oxide or hydroxide used is preferably in excess of that required to convert the sulphur in the proteinaceous material to the insoluble sulphide of the heavy metal.  The solution may then be filtered and any metal in solution derived from the hydrolysing agent removed and finally the solution is concentrated down to remove excess water.  In an example, dried blood is heated with water which may contain up to 0.025 mols. caustic soda, in the presence of litharge in a sealed autoclave at 105 DEG  to 110 DEG  C. for 24 hours after which the contents are filtered, zinc dust added to precipitate dissolved lead and the solution again filtered and concentrated to a nitrogen content of 4.5 to 5 per cent.  The solution gives foams with air and fresh or salt water. Specification 517,767 is referred to.  The Specification as open to inspection under Sect. 91 is not limited to the use of the above-mentioned metallic oxides and hydroxides, but includes any having medium basic properties and an aqueous medium whose pH is above 10, for example, pH 11 may be employed.  It is stated that the metal in solution derived from the hydrolysing agent may be removed by precipitation by means of a finely-divided metal which precedes it in the electro-chemical series.  This subject-matter does not appear in the Specification as accepted.