Formaldehyde free composites made with carbohydrate and alpha-carbon nucleophile binder compositions
Fiber-containing composites are described that contain woven or non-woven fibers, and a cured binder formed from a binder composition that includes (1) a reducing sugar and (2) a crosslinking agent that includes a first carbon moiety selected from an aldehyde, a ketone, a nitrile, and a nitro group, wherein an α-carbon atom having at least one acidic hydrogen is directly bonded to the first carbon moiety. Exemplary reducing sugars include dextrose and exemplary crosslinking agents include glyoxal. Exemplary fiber-containing composites may include fiberglass insulation.
1 . A fiber-containing composite comprising:
woven or non-woven fibers; and
a cured binder formed from a binder composition comprising:
a carbohydrate;
a crosslinking agent that is an organic compound comprising:
a first carbon moiety comprising an electron withdrawing group; and
an α-carbon atom directly bonded to the first carbon moiety,
wherein the α-carbon atom has at least one acidic hydrogen atom, and
one or more additional binder components selected from the group consisting of polymerization catalysts, dedusting oils, waxes, biocides, inorganic fillers, and colorants;
wherein the α-carbon atom forms a nucleophile that reacts with a carbonyl carbon on the carbohydrate during polymerization of the binder composition to form the cured binder; and wherein the molar ratio of crosslinking agent to carbohydrate is from 1:4 to 1:10.
2 . The fiber-containing composite of claim 1 , wherein the woven or non-woven fibers are glass fibers.
3 . The fiber-containing composite of claim 1 , wherein the carbohydrate is an aldose or ketose.
4 . The fiber-containing composite of claim 1 , wherein the carbohydrate is dextrose.
5 . The fiber-containing composite of claim 1 , wherein the first carbon moiety comprising an electron withdrawing group is selected from an aldehyde, a ketone, a nitrile, and a nitro group.
6 . The fiber-containing composite of claim 1 , wherein the binder composition further comprises a polymerization catalyst.
7 . The fiber-containing composite of claim 6 , wherein the polymerization catalyst comprises an inorganic acid catalyst.
8 . The fiber-containing composition of claim 7 , wherein the inorganic acid catalyst is chosen from at least one of hydrochloric acid, sulfuric acid, sulfonic acid, and nitric acid.
9 . The fiber-containing composite of claim 8 , wherein the polymerization catalyst comprises an organic acid catalyst.
10 . The fiber-containing composition of claim 9 , wherein the organic acid catalyst is chosen from at least one of acetic acid, citric acid, maleic acid and poly acrylic acid.
11 . The fiber-containing composite of claim 1 , wherein the carbohydrate is a reducing sugar and the polymerization catalyst is citric acid.
12 . The fiber-containing composite of claim 11 , wherein the citric acid is present in the binder composition at 0.1-1.0 mole per mole of reducing sugar.
13 . The fiber-containing composite of claim 1 , wherein the binder composition further comprises at least one of a coupling agent, a dedusting oil, a biocide, a flame retardant, a wetting agent, a wax, and an anti-foaming agent.
14 . The fiber-containing composite of claim 1 , wherein the binder composition has a pH from about 4 to about 8.
15 . The fiber-containing composite of claim 1 , wherein the binder composition additionally contains up to 40 wt. % of starch or polyvinyl alcohols.
16 . The fiber-containing composite of claim 1 , wherein the binder composition include (i) carbohydrate in amounts of 40 to 90 wt. %, (ii) crosslinking agent in amounts of 0.1 to 20 wt. %, (iii) organic acid in amounts of 10 to 40 wt. %, (iv) starch being different from the aforementioned carbohydrate (i) in amounts of 0.1 to 30 wt. %.
17 . The fiber-containing composite of claim 1 , wherein the woven or non-woven fibers comprise about 50 wt. % to about 99.5 wt. % of the fiber-containing composite.
18 . The fiber-containing composite of claim 1 , wherein the binder composition comprises about 5 wt. % to about 50 wt. % solids.
19 . The fiber-containing composite of claim 1 , wherein the binder composition lacks ammonia.
20 . The fiber-containing composite of claim 1 , wherein the binder composition is applied prior to curing on the woven or non-woven fibers, and the polymerization of the binder composition occurs at a temperature of about 120° C. to about 150° C.
21 . The fiber-containing composite of claim 1 , wherein the fiber-containing composite is chosen from piping insulation, duct boards, duct liner, duct wrap, flexible duct media, pipe insulation, tank insulation, rigid plenum liner, textile duct liner insulation, equipment liner, oven insulation, elevated temperature board, elevated temperature wrap, elevated temperature panel, insulation batts, insulation rolls, heavy density batt insulation, light density batt insulation, exterior foundation insulation board, and marine hull insulation.
22 . The fiber-containing composite of claim 1 , wherein the carbohydrate is an aldose or ketose and the crosslinking agent is an aldose or ketose, the binder composition further comprising a strong acid having a pKa of 4.0 and lower, the strong acid being present at 1% to 10% by mass of aldose and/or ketose.
23 . The fiber-containing composite of claim 1 , wherein the binder composition include (i) aldose and/or ketose in amounts of 90 to 99 wt. %, (ii) strong acid having a pKa of 4.0 and lower being present in 1% to 10% by mass of aldose and/or ketose, (iii) crosslinking agent in amounts of 0.0 to 20 wt. %, (iv) organic acid in amounts of 0.0 to 40 wt. %, (v) starch being different from the aforementioned aldose and/or ketose (i) in amounts of 0.0 to 30 wt. % (all percentage refer to dry weight percentage).