Antipunking phenolic resin binder systems for mineral fiber thermal insulation
AssigneeMonsanto Company
InventorHarold P. Higginbottom
Life of this patent
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Abstract
Phenolic resin antipunk systems for thermal insulation, characterized by stability and a low level of volatile pollutants. The aqueous resin systems contain a resole component and an antipunk component. They are prepared by a three-step reaction which controls the degree of reaction, the molecular weight and the water tolerance of the resole component. Stability is promoted by inhibition of the crystallization of bis(4-hydroxy-3,5-dimethylolphenyl) methane.
Claims19
A single-phase storage-stable aqueous phenolic antipunk resin system which comprises a resole and a condensate of formaldehyde and a nitrogenous compound selected from the group consisting of ammonia, urea, dicyandiamide and melamine;
- wherein the system has a pH in the range of 6 to 8.5 and contains less than 2 percent of free phenol and less than 2 percent of free formaldehyde based on the weight of the resole, wherein the resole has a number average molecular weight of less than 400, a water tolerance in the range of about 50 to 800 percent and a combined formaldehyde to phenol molar ratio in the range of 2.0:1 to 2.5:1;
- wherein the condensate has a molar ratio of combined formaldehyde to nitrogenous compound in the range of 0.5:1 to 1.5:1;
- wherein the molar ratio of combined phenol to nitrogenous compound is in the range of about 0.61:1 to 2:1 producing an antipunk resin system;
- and wherein the resin system contains sufficient methylolated 2,2'-and 2,4'-dihydroxydiphenylmethanes to inhibit crystallization of the resole.
A process for preparing an aqueous solution of a phenolic antipunk resin system which comprises:
- a. reacting 1.0 mole phenol with from 0.05 to 0.30 moles formaldehyde under conditions for formation of novolac resin,
- b. adding from 1.75 to 4.0 moles formaldehyde and reacting under basic conditions to produce a resole of molecular weight less than 400 and water tolerance between about 50 and 800 percent, and containing less than 2 weight percent free phenol;
- c. adding between about 0.5 and 1.64 moles of a nitrogenous compound selected from the group consisting of ammonia, urea, dicyandiamide and melamine and reacting the nitrogenous compound to produce an antipunk resin system and to reduce the free formaldehyde content to less than 2 weight percent of the resole, and
- d. adjusting the pH to between 6 and 8.5 at 25.degree.C.
A process for preparing an aqueous solution of an emulsifiable phenolic resin system which comprises:
- a. reacting 1.0 mole phenol with from 0.05 to 0.30 moles formaldehyde under conditions for formation of novolac resin,
- b. adding from 1.75 to 4.0 moles formaldehyde and reacting under basic conditions to produce a resole of molecular weight less than 400 and water tolerance between about 50 and 800 percent, and containing less than 2 weight percent free phenol,
- c. adding between about 0.5 and 1.64 moles of a nitrogenous compound selected from the group consisting of ammonia, urea, dicyandiamide and melamine and reacting the nitrogenous compound to reducee the free formaldehyde content to less than 2 weight percent of the resole,
- d. adjusting the pH to between 6 and 8.5 at 25.degree.C., and
- e. adding between about 0.1 and 5.0 parts by weight of a proteinaceous compound soluble in aqueous media at a pH of 7 to 10, per 100 parts by weight of the resin system solids.
Dependencies are inferred from the claim text.