Phenol-formaldehyde resin solution containing water soluble alkaline earth metal salt

Claim 2

A process for preparing a urea-free aqueous solution of a water soluble resole resin having improved storage stability for subsequent use in preparing a binder for mineral fibers, the process comprising: (a) preparing an aqueous mixture of at least one aldehyde and at least one phenol, the molar ratio of aldehyde to phenol being from about 1.5: 1 to 5.0 : 1; (b) adding an alkaline earth metal compound to the aqueous mixture in an amount effective to catalyze the reaction between the aldehyde and the phenol; (c) reacting the aldehyde and the phenol under basic conditions in the absence of urea and in the presence of the alkaline earth metal compound to form a urea-free aqueous solution of a resole resin; and (d) adding sulfamic acid to the urea-free aqueous solution prepared in step (c) to provide a resin solution having improved stability in an amount sufficient to provide a pH from about 1 to 8.

Claim 3

A process according to claim 1 wherein at least one phenol is phenol and at least one aldehyde is formaldehyde.

Claim 4

A process according to claim 2 wherein the alkaline earth metal is selected from calcium and barium.

Claim 5

A process according to claim 3 wherein the alkaline earth metal is calcium.

Claim 6

A process according to claim 4 wherein the calcium compound is selected from calcium oxide and calcium hydroxide.

Claim 7

A process according to claim 4 wherein the molar ratio of formaldehyde to phenol is from about 3.2 : 1 to 3.8 : 1.

Claim 8

A process according to claim 4 wherein the calcium compound is added in an amount from about 1% to 10% by weight, calculated as calcium oxide on the weight of phenol.

Claim 9

A process according to claim 7 wherein the calcium compound is added in an amount from about 3% to 6% by weight, calculated as calcium oxide on the weight of phenol.

Claim 10

A process according to claim 4 wherein the sulfamic acid is added in an amount sufficient to adjust the acidity of the solution to a pH of from about 6.0 to 7.0

Claim 11

A process according to claim 1 wherein the sulfamic acid is added to the resin solution to provide an acidic solution, the solution being subsequently neutralized by addition of a base.

Claim 12

A process according to claim 10 wherein the base is selected from monoethanolamine, diethanolamine and triethanolamine, the resin solution being neutralized to a pH of about 7 or greater.

Claim 13

A process according to claim 5 wherein the temperature of the aqueous mixture of formaldehyde and phenol is maintained at a first temperature of from about 40° C. to 50° C. as the catalyst is added, the temperature then being adjusted to rise to a second temperature of from about 60° C. to 80° C. within about 30 minutes and maintained until the free formaldehyde content declines to a level of about 10% by weight of the reaction mixture solids.

Claim 14

A process according to claim 12 wherein the reaction mixture is neutralized with solid sulfamic acid, the reaction mixture being cooled to between about 30° C. and 40° C. before addition of the sulfamic acid.

Claim 15

An aqueous solution of phenol-formaldehyde resin prepared according to process of claim 4.

Claim 16

A process for preparing a binder for mineral fibers, the process comprising preparing an aqueous solution of a water soluble urea-free resole resin having improved storage stability, the binder being prepared by a process comprising: (a) preparing an aqueous mixture of at least one aldehyde and at least one phenol, the molar ratio of the aldehyde to the phenol being from about 1.5 : 1 to 5.0: 1; (b) adding an alkaline earth metal compound to the aqueous mixture in an amount effective to catalyze the reaction between the aldehyde and the phenol; (c) reacting the aldehyde and the phenol under basic conditions in the absence of urea and in the presence of the alkaline earth metal compound to form a urea-free aqueous solution of a resole resin; (d) adding sulfamic acid to the urea-free aqueous solution prepared in step (c) to provide a resin solution having improved stability in an amount sufficient to provide a pH from about 1 to 8, and (e) subsequently adding at least one nitrogenous reactant selected from urea, ammonia, ammonium salts, dicyandiamide, meladine, and aminoplast resins to the urea-free aqueous solution including sulfamic acid.

Claim 17

A process for preparing a binder for mineral fibers, the process comprising preparing an aqueous solution of a water soluble urea-free resole resin having improved storage stability, the binder being prepared by a process comprising: (a) preparing an aqueous mixture of at least one aldehyde and at least one phenol, the molar ratio of the aldehyde to the phenol being from about 1.5 : 1 to 5.0: 1; (b) adding an alkaline earth metal compound to the aqueous mixture in an amount effective to catalyze the reaction between the aldehyde and the phenol; (c) reacting the aldehyde and the phenol under basic conditions in the absence of urea and in the presence of the alkaline earth metal compound to form a urea-free aqueous solution of a resole resin; (d) adding sulfamic acid to the urea-free aqueous solution prepared in step (c) to provide a resin solution having improved stability in an amount sufficient to provide a pH from about 1 to 8, and (e) subsequently adding at least one nitrogenous reactant selected from urea, ammonia, ammonium salts, dicyandiamide, meladine, and aminoplast resins to the urea-free aqueous solution including sulfamic acid.

Claim 18

A process according to claim 15 wherein the nitrogenous reactant is urea.

Claim 19

A process according to claim 15 wherein the nitrogenous reactant is added in an amount sufficient to react with substantially all residual formaldehyde in the aqueous resole solution.

Claim 20

A process according to claim 17 wherein the nitrogenous reactant is added in an amount up to about 75% by weight based on the weight of total solids.