Claim 1
Independent Claim
631 words
I claim: .[.1. An improved process for producing stable urea-aldehyde insulating foams having properties of improved structural strength and low formaldehyde vapor emission, from two separate storable liquids, said process comprising: blending an air-foamed solution containing dialdehydes having two to eight molecular carbons, surfactant, and mineral acid, with a partially cured aqueous urea-formaldehyde resin containing between 1.3 and 1.5 mols of formaldehyde per mol of urea and about 50 percent total solids, so that the molecular aldehyde moieties supplied by the dialdehyde are between 0.2 and 0.4 times the number of aldehyde moieties supplied by formaldehyde, and the molecular ratio of total aldehyde moieties to urea is between 1.7 and 2.0; curing and drying the blended fluids at a pH between 2.0 and 3.5 at ambient conditions until the foam hardens..]. .[.2. The process of claim 1 wherein dipropylene glycol, sorbitol, or polyethylene glycols, are added to the partially cured resin solution..]. .[.3. The process of claim 1 wherein attapulgite clay, or colloidal silica are added to the aqueous dialdehyde solution..]. .[.4. The process of claim 1 wherein the blended urea-aldehyde foam is applied as contiguous mass into a thin-skinned container to harden into a structural member..]..Iadd. 5. An improved process for producing stable urea-aldehyde polymers, having properties of high structural strength and low free formaldehyde content, from two separate storable fluids, said process comprising: blending aqueous alkyl or aryl, dialdehydes containing between two and eight molecular carbons with partially cured aqueous urea-formaldehyde resin, containing between 1.2 and 1.7 mols of formaldehyde per mol of urea and about 50 percent total solids, so that the molecular aldehyde moieties supplied by the dialdehydes are between 0.1 and 1.0 times the number of aldehyde moieties supplied by formaldehyde, and the molecular ratio of total aldehyde moieties to urea is between 1.6 and 2.2; and curing and drying the blended fluids at a pH between 2 and 5 until the polymer hardens. .Iaddend. .Iadd. 6. An improved process for producing stable urea-aldehyde polymers, having properties of high structural strength and low free formaldehyde content, from two separate storable fluids, said process comprising: blending aqueous alkyl dialdehydes containing between two and eight molecular carbons with partially cured aqueous urea-formaldehyde resin containing between 1.3 and 1.5 mols of formaldehyde per mol of urea and about 50 percent total solids, so that the molecular aldehyde moieties supplied by the dialdehyde are between 0.2 and 0.4 times the number of aldehyde moieties supplied by formaldehyde, and the molecular ratio of total aldehyde moieties to urea is between 1.7 and 2.0; and curing and drying the blended fluids at a pH between 2 and 5 until the polymer hardens. .Iaddend..Iadd. 7. The process of claim 6 wherein the alkyl dialdehyde is glyoxal, and, or, suberic aldehyde. .Iaddend..Iadd. 8. An improved process for producing stable urea-aldehyde polymer filled wood particle board having properties of increased structural strength and decreased free formaldehyde from two separate storage liquids, said process comprising: blending one part partially cured aqueous urea-formaldehyde resin containing between 1.3 and 1.5 mols of formaldehyde per mol of urea and about 50 percent total solids, with between 6 and 12 parts finely divided wood particles; evenly spraying the blended wood particles with an aqueous solution containing alkyl dialdehydes having between two and eight molecular carbons so that the molecular aldehyde moieties supplied by the dialdehyde are between 0.2 and 0.4 times the number of aldehyde moieties supplied by formaldehyde, and the molecular ratio of total aldehyde moieties to urea is between 1.7 and 2.0; and curing and drying by heating and pressing the total mixture to a temperature between 120° and 180° C. for 3 to 45 minutes, at pressures between 50 and 500 pounds per square inch, so that pH is reduced to about 5 during the cure. .Iaddend.