Extended curable compositions for use as binders

Abstract

The present invention provides low-cost formaldehyde-free curable aqueous compositions comprising 100 weight parts of one or more than one binder chosen from (i) mixtures of one or more than one polycarboxylic acid or polymeric polyacid and one or more than one polyol compound comprising at least two hydroxyl or epoxy groups, (ii) copolymers or copolymeric polyacids bearing carboxylic acid groups or anhydride groups and hydroxyl groups, and (iii) mixtures thereof, and 10 to 40 weight parts of one or more than one extender having an average particle size ranging from 0.5 μm or more and as high as 45 μm or less, preferably chosen from microcrystalline silica, diatomaceous silica, kaolin, bentonite, and anhydrous aluminosilicate clay delaminated. In the inventive binder compositions, the ratio of the wet over dry tensile strength of said composition is about 0.5 or greater. The present invention further provides products coated or impregnated with the binder, such as heat-resistant fiberglass nonwovens used for insulation. The aqueous binder may further comprise one or more phosphorous-containing accelerator.

Description

FIELD OF THE INVENTION [0001] The present invention relates to reduced cost, formaldehyde-free curable aqueous binder compositions containing extenders and yet retain their hot wet tensile strength properties when cured. More specifically, the present invention relates to compositions comprising from 10 to 40 weight % of one or more extender, based on the weight of one or more formaldehyde-free curable aqueous binder, wherein the ratio of the hot-wet tensile strength to the dry tensile strength of said composition, is about 0.5 or greater. BACKGROUND OF THE INVENTION [0002] Binders for heat-resistant non-woven materials, such as fiberglass insulation, have mostly contained resins, such as formaldehyde condensate resins that include urea-formaldehyde (UF) and phenol-formaldehyde (PF). These resins are inexpensive, however they steadily emit harmful formaldehyde gasses over their useful life. Further, such resins tend to yellow over time and can emit a foul odor when wet. [0003] Recen...

AI Technical Summary

Problems solved by technology

These resins are inexpensive, however they steadily emit harmful formaldehyde gasses over their useful life.

Further, such resins tend to yellow over time and can emit a foul odor when wet.

Such aqueous acrylic resins, despite being odor-free and emitting virtually no formaldehyde have increased the cost of manufacturing fiberglass insulation or other fibrous products compared to costs associated with the use formaldehyde condensates.

However, the auxiliaries mentioned can hamper the effectiveness of the binder or reduce the strength of the cured binder below acceptable levels.

For example, pyrogenic silica, like any nanoparticle-size additive, can absorb binder, thereby masking its effectiveness.

Calcium carbonate and iron oxide both interfere with the condensation reaction that cures the binder, and the carbonate also induces foaming and neutralizes the carboxylic acid functional polymer.

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