Patent GB-924228-A (GB)
Title: Polyurethane foam material
IPC: C08J9/12
Filed: 1961-02-28
Abstract: A process for the production of polyurethane foams using linear or branched polyoxyalkylene polyhydric alcohols containing at least two hydroxyl groups and polyisocyanates and/or polyisothiocyanates comprises dispersing a gas substantially uniformly in the polyhydric alcohol, the dispersion being effected by injecting the gas under pressure into the polyhydric alcohol and then agitating the mixture until a uniform dispersion is obtained and thereafter reacting the polyhydric alcohol having the gas dispersed therein with an organic polyisocyanate and/or polyisothiocyanate and water and/or another blowing agent, the gas employed being one which is substantially inert with respect to the components entering into reaction.  The products obtained preferably have a density of 1,6 or less and a cell size of from about 0,01 to about 0,03 inch in cross-section.  It is preferred not to inject the gas while liquefied although it might be possible in some cases to do so.  The polyhydric alcohol may be a reaction product of an alkylene oxide with water or a polyhydric alcohol.  It may contain an aromatic ring, introduced by condensing an alkylene oxide with a phenol, such as hydroquinone or with a polyester prepared from an aromatic acid, such as terephthalic and a polyol such as glycerol.  As catalysts there are listed triethylene diamine and tertiary amine derivatives of morpholine, piperazine and tetrabutylene diamine. They are preferably used together with compounds of di- or tetravalent tin, such as stannous salts, dialkyltin salts, or a dialkyltin chloride, oxide, sulphide, alkoxide, diphenate or dinaphthanate or an alkyltin trialkoxide, triphenate or trinaphthanate.  Suitable di- and tri-isocyanates are listed.  A siloxane oxyalkylene block copolymer is also preferably present in the reaction mixture.  As blowing agents, water, methylene chloride, trichlorofluoromethane and isopentane are specified. Apparatus for effecting the process is described.  The gas is preferably injected into the polyhydric alcohol (moved by a gear pump) by an injection nozzle with a check valve which closes when the pressure on the alcohol is higher than that on the gas.  In an example (1) air is injected into a glycerol/propylene oxide reaction product of M.W. 3,000 to provide 10 parts by volume of air to 100 parts by weight of the polyol.  The mixture is stirred and then toluene 2,4- and 2,6-diisocyanates are injected and simultaneously water, stannous octoate, N-ethyl morpholine, triethylene diamine and a polysiloxane oxyalkylene block copolymer are mixed in.  The mixture is discharged before any substantial reaction has taken place and then reacts to give a polyurethane foam of density 1,6 lbs. per cubic foot.  It is also possible to inject the other components separately into the gas-containing polyol.  Specifications 769,682 and 804,369 are referred to.ALSO:A process for the production of polyurethane foams using linear or branched polyoxyalkylene polyhydric alcohols containing at least two hydroxyl groups and polyisocyanates and/or polyisothiocyanates comprises dispersing a gas substantially uniformly in the polyhydric alcohol, the dispersion being effected by injecting the gas under pressure into the polyhydric alcohol and then agitating the mixture until a uniform dispersion is obtained and thereafter reacting the polyhydric alcohol having the gas dispersed therein with an organic polyisocyanate and/or polyisothiocyanate and water and/or another blowing agent, the gas employed being one which is substantially inert with respect to the components entering into reaction.  The products obtained preferably have a density of 1,6 or less and a cell size of from about 0,01 to about 0,03 inch in crosssection.  It is preferred not to inject them while liquefied although it might be possible in some cases to do so.  The polyhydric alcohol may be a reaction product of alkylene oxide with water or a polyhydric alcohol.  It may contain an aromatic ring, introduced by condensing an alkylene oxide with a phenol, such hydroquinone or with a polyester prepared from an aromatic acid, such terephthalic and a polyol such as glycerol.  As catalysts there are listed triethylene diamine and tertiary amine derivatives of morpholine, piperazine and tetrabutylene diamine.  They are preferably used together with compounds of di- or tetravalent tin, such as stannous salt, dialkyltin salts, or a dialkyltin chloride, oxide, sulphide, alkoxide, diphenate or dinaphthanate or an alkyltin trialkoxide, triphenate trinaphthanate.  Suitable di- and triisocyanates are listed.  A siloxane oxyalkylene block copolymer is also preferably present in the reaction mixture.  As blowing agents, water, methylene chloride, trichlorofluoromethane and isopentane are specified. Apparatus for effecting the process is described.  The gas is preferably injected into the polyhydric alcohol (moved by a gear pump) by an injection nozzle with a check valve which closes when the pressure on the alcohol is higher than that on the gas.  In an Example (1) air is injected into a glycerol/propylene oxide reaction product of M.W. 3000 to provide 10 parts by volume of air to 100 parts by weight of the polyol. The mixture is stirred and then toluene 2, 4- and 2, 6-diisocyanates are injected and simultaneously water, stannous octoate, N-ethylmorpholine, triethylene diamine and a polysiloxane oxyalkylene block copolymer are mixed in.  The mixture is discharged before any substantial reaction has taken place and then reacts to give a polyurethane foam of density 1,6 lbs. per cubic foot.  It is also possible to inject the other components separately into the gas-containing polyol.  Specifications 769,682 and 804,369 are referred to.