Formaldehyde free binder compositions with urea-aldehyde reaction products

Abstract

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 reaction product of a urea compound and a polycarbonyl compound. Exemplary reaction products for the crosslinking agent may include the reaction product of urea and an α,β-bicarbonyl compound or an α,γ-bicarbonyl compound. Exemplary fiber-containing composites may include fiberglass insulation.

Description

CROSS-REFERENCES TO RELATED APPLICATIONS[0001]This application is a continuation-in-part of prior U.S. patent application Ser. No. 13 / 490,638, filed Jun. 7, 2012, entitled “Formaldehyde Free Binder Compositions With Urea-Aldehyde Reaction Products, (the “parent application”) which is incorporated herein by reference for all purposes.BACKGROUND OF THE INVENTION[0002]Organic binders for composite fiber products such as fiberglass insulation are moving away from traditional formaldehyde-based compositions. Formaldehyde is considered a probable human carcinogen, as well as an irritant and allergen, and its use is increasingly restricted in building products, textiles, upholstery, and other materials. In response, binder compositions have been developed that reduce or eliminate formaldehyde from the binder composition.[0003]One type of these formaldehyde-free binder compositions rely on esterification reactions between carboxylic acid groups in polycarboxy polymers and hydroxyl groups in...

AI Technical Summary

Benefits of technology

[0006]The binder composition may be applied to a group of fibers to form an pre-cured amalgam of binder composition and fibers. The amalgam may then be exposed to curing conditions (e.g., heating) to facilitate the curing of the binder and formation of a fiber-containing composite. During the curing stage, the crosslinking agent crosslinks the reducing sugar to form a polymeric matrix that adheres the fibers together in the fiber-containing composite. Examples of these composites include fiber insulation (e.g., fiberglass insulation) for piping, ducts, buildings, and other construction applications.

[0007]Embodiments include binder compositions containing (1) a reducing sugar and (2) a reaction product of a urea compound and an aldehyde-containing compound. The binder composition may be applied to a group of fibers and exposed to curing conditions to form a fiber-containing composite of fibers bound by the cured binder.

[0008]A more specific embodiment of the binder composition may include dextrose as the reducing sugar, and 4,5-dihydroxyimidazolidin-2-one as the reaction product of a urea compound (in this case H2N—CO—NH2) and glyoxal (OHC—CHO). When the dextrose and 4,5-dihydroxyimidazolidin-2-one are exposed to binder curing conditions, the 4,5-dihydroxyimidazolidin-2-one crosslinks the dextrose (and polymerized forms of dextrose) to make the cured binder.

[0009]Embodiments further include fiber-containing composites containing woven or non-woven fibers and a cured binder formed from a binder composition that includes (1) reducing sugar and (2) a crosslinking agent that is a reaction product of a urea compound and an aldehyde-containing compound. The fibers may be one or more types of fibers chosen from glass fibers, mineral fibers, and organic polymer fibers (among others). Non-woven glass fibers may be included in composites for fiberglass insulation.

[0010]Embodiments still further include methods of binding fibers, where the methods include the step of applying a binder composition to a mat of woven or non-woven fibers, and then curing the binder composition applied to the fibers to make a fiber-containing composite. The binder composition may include a reducing sugar and a crosslinking agent formed as a reaction product between a urea compound and an aldehyde-containing compound, as described above.

Problems solved by technology

Formaldehyde is considered a probable human carcinogen, as well as an irritant and allergen, and its use is increasingly restricted in building products, textiles, upholstery, and other materials.

However, these formaldehyde-free binder compositions also make extensive use of non-renewable, petroleum-based ingredients.

However, many types of carbohydrate-containing binders tend to become brittle when cured and form excessive particulates when the insulation is folded or compressed.

Some carbohydrate-containing binders are also prone to accelerated degradation in humid environments and thus require additional conditioning and additives to improve their moisture / water resistance.

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