Curable sheared or extruded, cross linked starch nanoparticle latex binder for use with mineral, natural organic or synthetic fibre products and non-woven mats
A curable aqueous binder composition comprising sheared or extruded cross linked starch particles and a crosslinking agent for use in the formation of composite materials such as mineral, natural organic or synthetic fiber products including mineral fiber insulation, non-woven mats, fiberglass insulation and related glass fiber products as well as wood based products and construction materials. In one application the curable aqueous starch binder composition may be blended with a second non-formaldehyde resin to make fiberglass insulation. In another application the curable aqueous starch binder composition may be mixed into a formaldehyde based resin to make fiberglass roof shingles.
1. A method for forming a composite material, the method comprising the steps of:
(a) providing a reinforcement material selected from the group consisting wood chips, sawmill shavings, saw dust, wood veneers, wood strips, and mixtures thereof;
(b) applying a curable binder to at least some of the reinforcement material, wherein the curable binder comprises (i) a latex including internally crosslinked biopolymer nanoparticles in water, and (ii) a crosslinking agent in solution with the water; and
(c) curing the curable binder to form a cured binder joining at least a portion of the reinforcement material.
2. The method of claim 1 wherein:
step (c) comprises heating the curable binder and reinforcement material at a temperature of 130° C. to 230° C. for sufficient time to cure the curable binder.
3. The method of claim 1 wherein:
the crosslinking agent in solution with the water is a formaldehyde based resin.
4. The method of claim 1 wherein:
the crosslinking agent in solution with the water is a substantially water-dilutable or dispersible adduct of co-condensation of urea and formaldehyde.
5. The method of claim 1 wherein:
the biopolymer nanoparticles have an average particle size ranging from 1 to 1000 nanometers.
6. The method of claim 1 wherein:
the biopolymer nanoparticles are present in the curable binder at a concentration of between 4% and 50% by weight of the curable binder.
7. The method of claim 6 wherein:
the biopolymer nanoparticles are present in the curable binder at a concentration of between 10% and 20% by weight of the curable binder.
8. The method of claim 1 wherein:
the crosslinking agent in solution with the water is present in the curable binder at a concentration of between 0.1% and 10% by weight of the curable binder.
9. The method of claim 1 wherein the curable binder is substantially formaldehyde free.
10. The method of claim 1 wherein the crosslinking agent is glyoxal.
11. The method of claim 1 wherein the crosslinking agent is tetraethyl orthosilicate.