Inverted novolac resin-type insulation binder
View Patent ↗A substantially infinitely water-dilutable resole (P:F) resin solution useful for preparing an aqueous binder composition and the related method of its use for making glass fiber products, especially fiberglass insulation.
1. A substantially infinitely water-dilutable aqueous resole resin solution having a tetradimer content below about 23% by weight of resin solids and being suitable for making a binder composition for preparing glass fiber products, said resole resin comprising the base catalyzed reaction product, at a reaction temperature below about 60° C., of (i) a novolac resin and (ii) formaldehyde in an amount sufficient to establish a cumulative F:P mole ratio for said resole resin of at least 3.5:1, in order to favor methylolation of dimers present in the novolac resin during production of the resole resin, said resole resin having an amount of free formaldehyde of above 16 wt. % of resin solids and an amount of free phenol below about 1.5 wt. % of resin solids.
2. The resole resin of claim 1 having a pH in the range of 8.0 to 9.5.
3. The resole resin of claim 1 wherein the novolac resin has a formaldehyde to phenol mole ratio of 0.05:1 to 0.25:1.
4. The resole resin of claim 1 wherein the F:P mole ratio for said resole resin is at least about 3.7:1.
5. The resole resin of claim 3 wherein the cumulative F:P mole ratio for said resole resin is at least about 3.7:1.
6. The resole resin of claim 1 wherein the reaction temperature is about 55° C.
7. The resole resin of claim 5 wherein the reaction temperature is about 55° C.
8. A binder composition suitable for binding together a loosely associated mat of glass fibers comprising the resole resin of claim 1 , claim 4 , claim 5 or claim 7 reacted with urea, in an amount sufficient to provide a urea to free formaldehyde mole ratio in the range of 0.6:1 to 1:1.25.
9. A method for binding together a loosely associated mat of glass fibers comprising (1) contacting said glass fibers with an aqueous binder composition comprising an aqueous solution of substantially infinitely water-dilutable resole resin solution of claim 1 , claim 4 , claim 5 or claim 7 , and (2) heating said aqueous binder composition at an elevated temperature sufficient to effect cure.
10. An glass fiber product comprising a crosslinked (cured) composition obtained by curing an aqueous binder composition comprising an aqueous solution of a substantially infinitely water-dilutable resole resin solution of claim 1 , claim 4 , claim 5 or claim 7 applied to a mat of nonwoven glass fibers.
11. The glass fiber product of claim 10 wherein the glass fiber product is fiberglass insulation product.