Patent GB-1108503-A (GB)
Title: Method of and apparatus for the production of expanded aminoplasts and modification of the cellular structure thereof
IPC: B29B7/74
Filed: 1965-02-17
Abstract: Foamed aminoplasts are produced and have their cellular structure modified by mixing a foamed-up foaming agent, a water-soluble aminoplast resin and a hardening agent and, during or after the admixing of the reaction components leading to the hardening of the foamed aminoplast resing produced and shortly bedore injection moulding or extrusion, adding continuously a dry mixture of gas, particularly air, and at least one pulverulent additive to the foamed aminoplast resin being produced while the latter is in a shaped but not fully hardened condition.  The aminoplasts are the water-soluble resins obtained by condensation of urea and/or thiourea with formaldehyde in the presence of catalysts and at an elevated temperature. The foamed-up foaming agent is any foaming agent in solution or dispersion which has been foamed, e.g. by beating up or stirring.  Suitable additives are surface-active grease-free soot, dry resin, glue, aminoplast resin precondensate powder which has been ground to micro-fineness and which optionally has been modified with organic or inorganic substances, particularly substances having hydraulic setting action, furfural-modified aminoplast resin, foamed polystyrene in pellet form or foamed polystyrene waste, water-soluble polyester and/or phenol resin and/or acrylic resin mixed with a water-soluble aminoplast resin, and a water-soluble, air-dry polyester resin, optionally in admixture with styrene and/or polyhydric alcohol and/or an oxidation agent and/or a reducing agent. Compressed gas may be added shortly before moulding or extrusion. The mixtures of gas and pulverulent additive may produce gas with the other components. In examples are used an aqueous urea-formaldehyde precondensate modified with furfural, solution of phenol-formaldehyde resin in stage A, asbestos flour, silicic acid-impregnated wood flour, aqueous ortho-phosphorioc acid, a styrene solution of a polyester, an aqueous dispersion of bitumen, aqueous solution of lauryl alkanol sulphate, aluminium sulphate, calcium carbonate, aluminium chloride, gum arabic, aqueous oxalic acid solution, gypsum powder, grease-free soot and sodium silicate solution.ALSO:Nitrogenous or mixed fertilizers and trace elements are incorporated into foamed aminoplasts which are produced and have their cellular structure modified by mixing a foamed up foaming agent, a water soluble aminoplast resin and a hardening agent and during or after the admixing of the reaction components leading to the hardening of the foamed aminoplast resin produced and shortly before injection moulding or extrusion, adding a dry mixture of gas and at least one pulverulent additive, containing the fertilizers, continuously to the foamed aminoplast resin being produced, while the latter is in a shaped but not fully hardened condition.  Suitable fertilizers are crotonylidene-diurea or urea compounds with paraformaldehyde and acetaldehyde, casein, leather flour, chlorides, sulphates, phosphates, nitrates, aminoplast resin, and cellulose. Seeds and bulbs may be incorporated into the foam.ALSO:Disinfectants, bactericidal agents and poisons are incorporated into foamed aminoplasts which are produced and have their cellular structures modified by mixing a foamed-up foaming agent, a water soluble aminoplast resin and a hardening agent and, during or after the admixing of the reaction components leading to the hardening of the foamed aminoplast resin produced and shortly before injection moulding or extrusion, adding a dry mixture of gas and at least pulverulent additive containing the disinfectants &c., continuously to the foamed aminoplast resin being produced, while the latter is in a shaped but not fully hardened condition.  Suitable disinfectants are resorcinol, calcium chloride, potassium hydroxide, 1, 1, 1-trichloro-2, 2-bis-(p-chlorophenyl)-ethane, soda-lime and formaldehyde.