Patent GB-655677-A (GB)
Title: Improvements in or relating to hydrophobic surface treated inorganic particles and materials
IPC: C04B20/10
Filed: 1947-12-03
Abstract: In producing a hydrophobe or water-repellant powder, particles of an inorganic material are coated with an alkoxy silane having at least one tertiary alkoxy group and at least one hydrolysable substituent group, e.g. a halogen, amino, methoxy or ethoxy group joined to the silicon atom.  The powder may be of porous particles, of particles having a large relative surface area, e.g. silica gel, diatomaceous earth, exfoliated vermiculite, fibrous asbestos, or of non-porous particles, e.g. crushed silica, zinc oxide, titanium dioxide, limestone, slate flour, powdered or spheroidized glass particles, or of water-soluble inorganic powders, e.g. ammonium chloride crystals and sodium bicarbonate. The powder is mixed with a solution of the alkoxy silane, the solvent, e.g. heptane, being evaporated and the powder further heated.  A treated powder of porous particles such as diatomaceous earth may be mixed with a vulcanizable rubber latex-with or without 0.5 to 5 per cent methyl cellulose-and spread on poplin to give a porous but water-repellent cloth, or a treated powder of non-porous particles applied to a fabric base having a tacky rubber or synthetic resin composition coating on the threads insufficient to give a continuous coating.  The treated powders may also be used as fillers in paints, enamels, leather-finishing compositions, or shoe polishes, and sodium bicarbonate may be treated before storage in a humid atmosphere as e.g. in fire extinguishers.ALSO:Di-tertiary-butoxy dichlorosilane is made by reacting a solution of silicon tetrachloride with tertiary butyl alcohol, in the presence of alphapicoline or pyridine as acid acceptor.  Di-tertiary-butoxy diaminosilane is made by reacting a heptane solution of the di-tertiary-butoxy dichloro silane with ammonia under pressure.  In this latter reaction, ammonium chloride crystals coated with the silane may be separated.ALSO:In producing a hydrophobe or water-repellent powder, particles of an inorganic material are coated with an alkoxy silane having at least one tertiary alkoxy group, and at least one hydrolysable substituent group, e.g. a halogen, amino, methoxy or ethoxy group, joined to the silicon atom.  The powder may be of porous particles, or of particles having a large relative surface area, e.g. silica gel, diatomaceous earth, exfoliated vermiculite, fibrous asbestos, or of non-porous particles, e.g crushed silica, zinc oxide, titanium dioxide, limestone, slate flour, powdered or spheroidized glass particles, or of water-soluble inorganic powders, e.g. ammonium chloride crystals and sodium bicarbonate. The powder is mixed with a solution of the alkoxy silane, the solvent, e.g. heptane, being evaporated and the powder further heated.  A treated powder of porous particles such as diatomaceous earth may be mixed with a vulcanizable rubber latex-with or without 0.5 to 5 per cent methyl cellulose-and spread on poplin to give a porous but water-repellent cloth, or a treated powder of non-porous particles applied to a fabric base having a tacky rubber or synthetic resin composition coating on the threads insufficient to give a continuous coating.  The treated powders may also be used as fillers in paints, enamels, leather finishing compositions, or shoe polishes, and sodium bicarbonate may be treated before storage in a humid atmosphere as, e.g. in fire extinguishers.  Di - tertiary - butoxy dichlorosilane is made by reacting a solution of silicon tetrachloride with tertiary butyl alcohol, in the presence of alpha-picoline or pyridine as acid acceptor, and di-tertiary-butoxy diamino silane is made by reacting a heptane solution of the di-tertiary-butoxy dichloro silane with ammonia under pressure.  In this latter reaction, ammonium chloride crystals coated with the silane may be separated.ALSO:In producing a hydrophobe or water-repellant powder, particles of an inorganic material are coated with an alkoxy silane having at least one tertiary alkoxy group and at least one hydrolysable substituent group, e.g. a halogen, amino, methoxy or ethoxy group joined to the silicon atom.  The powder may be of porous particles, or of particles having a large relative surface area, e.g. silica gel, diatomaceous earth, exfoliated vermiculite, fibrous asbestos, or of non-porous particles, e.g. crushed silica, zinc oxide, titanium dioxide, limestone, slate flour, powdered or spheroidized glass particles, or of water-soluble inorganic powders, e.g. ammonium chloride crystals and sodium bicarbonate. The powder is mixed with a solution of the alkoxy silane, the solvent, e.g. heptane, being evaporated and the powder further heated.  A treated powder of porous particles such as diatomaceous earth may be mixed with a vulcanizable rubber latex-with or without 0.5 to 5 per cent methyl cellulose-and spread on poplin to give a porous but water-repellent cloth, or a treated powder of non-porous particles applied to a fabric base having a tacky rubber or synthetic resin composition coating on the threads insufficient to give a continuous coating.  The treated powders may also be used as fillers in paints, enamels, leather finishing compositions, or shoe polishes, and sodium bicarbonate may be treated before storage in a humid atmosphere as, e.g., in fire extinguishers.  Di-tertiary-butoxy dichlorosilane is made by reacting a solution of silicon tetrachloride with tertiary butyl alcohol, in the presence of alphapicoline or pyridine as acid acceptor, and di-tertiary-butoxy diamino silane is made by reacting a heptane solution of the di-tertiary-butoxy dichloro silane with ammonia under pressure.  In this latter reaction, ammonium chloride crystals coated with the silane may be separated.