An un-reacted substantially formaldehyde free curable binder solution for binding loose matter consists essentially of a solution obtainable by dissolving a reducing sugar, an ammonium salt acid precursor optionally a carboxylic acid or a precursor thereof and optionally ammonia in water.
1. A substantially formaldehyde free binder solution consisting essentially of a solution obtainable by dissolving
a reducing sugar, and
at least 2.5% by dry weight with respect to the reducing sugar of a material selected from the group consisting of ammonium sulphate salts, ammonium phosphate salts, ammonium nitrate salts, ammonium carbonate salts, and combinations thereof
in water.
2. The substantially formaldehyde free binder solution of claim 1 , in which the reducing sugar consists essentially of dextrose and there is at least 7% by dry weight of the salt material with respect to dextrose.
3. The substantially formaldehyde free binder solution in accordance with claim 1 , in which a carboxylic acid is included or provided in the form of an ammonium salt.
4. The substantially formaldehyde free binder solution in accordance with claim 1 , in which the pH of the solution is greater than 7.
5. The substantially formaldehyde free binder solution in accordance with claim 1 , in which the binder solution has a pH which, in its conditions of use, prevents precipitation of sulphates, phosphates, nitrates or carbonates.
6. The substantially formaldehyde free binder solution in accordance with claim 1 , in which material selected from the group consisting of ammonium sulphate salts, ammonium phosphate salts, ammonium nitrate salts, ammonium carbonate salts, and combinations thereof makes up between 5% and 25% by dry weight of the binder solution.
7. The substantially formaldehyde free binder solution in accordance with claim 1 , in which the binder solution contains at least 5% solids and less than 50% solids.
8. The substantially formaldehyde free binder solution in accordance with claim 1 , in which the ratio by dry weight of reducing sugar to material selected from the group consisting of ammonium sulphate salts, ammonium phosphate salts, ammonium nitrate salts, ammonium carbonate salts, and combinations thereof (expressed as dry weight of reducing sugar/dry weight of ammonium salt) is in the range 2.5 to 13.
9. The substantially formaldehyde free binder solution in accordance with claim 1 , in which the binder solution contains between 0.1% and 1% of a silane or silicon-containing coupling agent calculated as dissolved binder solids.
10. A method of manufacturing a product comprising the steps of:
providing a collection of loose matter;
treating the collection of loose matter with the substantially formaldehyde free binder solution of claim 1 ;
arranging the collection of loose matter treated with the binder solution into the shape of the product; and
curing the binder by applying a source of energy.
11. The method of claim 10 , in which the curing of the binder is carried out by passing the arranged collection of loose matter treated with the binder solution through at least one zone of a curing oven at a temperature within the range 230° C.-300° C. with an oven residence time in the range 30 seconds to 20 minutes.
12. The method of claim 10 , in which the curing of the binder is carried out by between platens of a press.
13. A material comprising a collection of loose matter and uncured or partially cured substantially formaldehyde free binder characterised in that the binder has a pH of greater than 6 when dissolved in water and comprises
a reducing sugar, and
at least 2.5% by dry weight with respect to the reducing sugar of an ammonium salt selected from the group consisting of ammonium sulphate salts, ammonium phosphate salts, ammonium nitrate salts, ammonium carbonate salts, and combinations thereof.
14. The material of claim 13 in which the loose matter comprises mineral fibres.
15. The material of claim 13 , having more than 500 mg/kg of species selected from the group consisting of sulphates, phosphates, nitrates, carbonates, and combinations thereof.
16. The material of claim 15 , in which the species selected from the group consisting of sulphates, phosphates, nitrates, carbonates, and combinations thereof is derived from the ammonium salt.
17. The material of claim 15 , in which the binder is partially cured and comprises melanoidins.