Water soluble phenolic resole-urea composition

A process for making a resinous binder that is substantially stable in cold storage at 0.degree. C. to 15.degree. C. for at least 30 days, comprising:

• dissolving in an aqueous resole solution, that contains free formaldehyde, from 0.3 to 3.0 moles of urea per mole of free formaldehyde, at 20.degree. C. to 40.degree. C., then
• acidifying said solution to a pH of 3.5 to 4.5 while maintaining the temperature at 20.degree. C. to 40.degree. C., and
• holding the solution in said pH range and in said temperature range for a sufficient period of time so that upon neutralization of said solution, the resole solution retains good solubility and is characterized by good inhibition of tetra dimer crystallization during cold storage at 0.degree. C. to 15.degree. C. such that any precipitate which forms comprises a flocculated sediment that is readily dispersed upon agitation.

A water soluble, cold storage stable resinous composition characterized by showing no signals of formation of hard insoluble phases for periods in excess of about 24 hours at temperatures of about 0.degree. C. to 15.degree. C., said composition comprising a phenolic resole containing free formaldehyde as prepared, that has been (1) reacted with a first amount of urea under acidic conditions of pH 3.5 to 4.5 and a temperature of from 10.degree. C. to 50.degree. C., wherein the molar ratio of free formaldehyde to urea added is in the range of from 0.3:1 to 3.0:1, (2) neutralized, and (3) further extended thereafter with a second amount of urea under neutral or slightly basic conditions.

A water soluble, cold storage stable resinous composition characterized by showing no signs of formation of hard insoluble phases for periods in excess of about 24 hours at temperatures of about 0.degree. to 15.degree. C., said composition comprising two resinous components comprising (1) a methylene urea polymer and (2) a phenolic resole, both being dissolved in an aqueous vehicle, said methylene urea polymer being present in sufficient amount that sedimentation and crystalization are inhibited during cold storage of said composition at 0.degree. C. to 15.degree. C. for periods in excess of 24 hours, said methylene urea polymer being produced by reaction of free formaldehyde within the aqueous vehicle and urea at a temperature in the range of about 10.degree. C. to 50.degree. C., at a pH of 3.0 to 5.8, for a period of from 15 to 40 minutes while maintaining the temperature of the mixture within the range of about 10.degree. C. to 50.degree. C., wherein the molar ratio of free formaldehyde to urea is in the range of from 0.3:1 to 3.0:1.

A water soluble, cold storage stable composition made by two successive additions of urea to a phenolic resole containing free formaldehyde as prepared, such that after said first urea addition in an amount which provides a molar ratio of free formaldehyde to urea in the range of 0.3:1 to 3.0:1, essentially any reaction proceeds under acidic conditions at a pH of 3.0 to 5.8 and a temperature of about 10.degree. C. to 50.degree. C., said acidic conditions being brought about by the addition of a non-buffer-forming, a non-precipitate-forming acid, said second addition of urea being made after a return to neutral or slightly basic conditions brought about by the addition of base.

An aqueous solution of a urea-modified resole that, after one month of storage at 0.degree. C., is substantially free of sediment and remains substantially infinitely water-dilutable, said composition comprising:

• a methylene urea polymer in a common aqueous vehicle with a phenolic resole, said polymer being formed by the addition of urea to a phenolic resole that contains free formaldehyde, in the proportion of 0.3 to 3.0 moles of urea per mole of free, uncombined formaldehyde in the resole, at a temperature of 10.degree. C. to 50.degree. C., and by the subsequent addition of an acidic material to adjust the pH to about 3.0 to about 5.0 while maintaining a temperature of about 10.degree. C. to 50.degree. C., and permitting the reaction to go forward for from 5 minutes to 60 minutes, to permit the formation of a methylene urea polymer, then adjusting the pH to a neutral or slightly basic value, the amount of said polymer, after neutralization, inhibiting sedimentation and crystallization during cold storage at 0.degree. C. to 5.degree. C.