METHOD OF MANUFACTURING COMPOSITE PRODUCTS COMPRISING A CARBOHYDRATE-BASED BINDER

Abstract

The present invention relates to the use of an amine compound comprising at least one, preferably at least two amine functions, wherein the amine functions are primary or secondary amines, to reduce the level of furfural and/or hydroxymethylfurfural in a carbohydrate-based binder or binder composition and/or escaping in the course of preparation, cross-linking and/or curing of carbohydrate-based binders. Preferably, the carbohydrate-based binder is obtained from a carbohydrate-based binder composition comprising a carbohydrate component and a cross-linker and possibly reaction product of carbohydrate component and cross-linker, wherein the cross-linker is selected from ammonium salts of inorganic acid, carboxylic acids, salts, ester or anhydride derivatives thereof, and/or combinations thereof.

Claims

1. A method for the preparation of a composite product comprising fibers and/or particles and/or sheet material bonded with a carbohydrate-based binder comprising (i) providing a binder composition comprising a carbohydrate component and at least 10% by dry weight of the binder composition and less than 50% by dry weight of the binder composition of a cross-linker and, optionally, a reaction product of the carbohydrate component and the cross-linker, wherein the cross-linker is selected from ammonium salts of inorganic acid, carboxylic acids, ammonium salts thereof, ester or anhydride derivatives thereof, and/or combinations thereof, (ii) adding to the binder composition an additional amount of from 0.5 to 10 wt. % (based on the total dry weight of the binder composition) of an amine compound comprising at least two amine functions, wherein the amine functions are primary or secondary amines, and the amine compound is selected from (a) aliphatic monoamines, the aliphatic group being a straight or branched saturated or unsaturated alkyl or hetero-alkyl chain having 2 to 24 C-atoms or cycloalkyl or cyclohetero-alkyl or an aromatic carbon ring structure, each optionally substituted by hydroxy, carboxyl, halo, cyanate, sulfonyl or thiol, (b) compounds of general formula H.sub.2N-Q-NH.sub.2 wherein Q is a straight or branched alkyl or heteroalkyl having 2 to 24 C-atoms, cycloalkyl, or cylcoheteroalkyl, an aromatic carbon ring structure, optionally substituted by hydroxy, carboxyl, halo, cyanate, sulfonyl and/or thiol, (c) whey or soy protein, optionally modified or denatured, (d) poly(primary amines) having a molecular weight of 5000 or less and 10 wt. % or more of primary amine groups based on the weight of the polyamine, (d) polyamino acids selected from lysine, ornithine, diaminobutyric acid and diaminopropionic acid, or (f) polyetheramines, polyethyleneimines, polyethyleneimine-containing copolymers and block copolymers, polyvinylamines, (co)polymers of aminoethyl methacrylate, (iii) applying the composition obtained under (ii) onto the fibers, particles and/or sheet material, and (iv) subjecting the product obtained under (iii) to heat and possibly pressure to effect drying and/or curing.

2. The method according to claim 1 wherein the cross-linker is ammonium sulphate or ammonium phosphate.

3. The method according to claim 1 wherein the cross-linker is a carboxylic acid, ammonium salts thereof, or ester or anhydride derivatives thereof.

4. The method according to claim 1 wherein the carbohydrate is selected from monosaccharides, disaccharides, oligosaccharides and polysaccharides and/or combinations thereof.

5. The method according to claim 1 wherein the carbohydrate component is a low MW polysaccharide selected from or derived from molasses, starch, starch hydrolysates, dextrines and derivatives, cellulose hydrolysates, hemicellulose hydrolysates or mixtures thereof.

6. The method according to claim 1 wherein the carbohydrate component is derived from higher molecular weight carbohydrates, wherein the level of C5-sugars or five-membered ring sugars varies from 10 to 70 wt. %.

7.-11. (canceled)

12. A method to reduce the level of furfural and/or hydroxymethylfurfural in a carbohydrate-based binder composition or binder and/or escaping from carbohydrate-based binders in the course of preparation, cross-linking and/or curing thereof, comprising the addition of an amine compound comprising at least two amine functions, wherein the amine functions are primary or secondary amines, to the binder composition during binder preparation and prior to curing.

13. The method according to claim 12 wherein the carbohydrate-based binder is obtained from a carbohydrate-based binder composition comprising a carbohydrate component and a cross-linker and, optionally, a reaction product of the carbohydrate component and the cross-linker, wherein the cross-linker is selected from ammonium salts of inorganic acid, carboxylic acids, ammonium salts thereof, ester or anhydride derivatives thereof, and/or combinations thereof.

14. The method according to claim 13 wherein the amine compound is used at a rate of 0.5 to 10 wt. %, based on the dry weight of the binder composition.

15. Composite product obtained by a method according to claim 1 comprising a reduced furfural and/or hydroxymethylfurfural content as compared with a composite product obtained from the same raw material transformed under the same processing conditions but with no added amine compound comprising least two amine functions, wherein the amine functions are primary or secondary amines.

16. The method according to claim 3 wherein the carboxylic acid is a polycarboxylic acid.

17. The method according to claim 3 wherein the carboxylic acid is a monomeric polycarboxylic acid

18. The method according to claim 4 wherein the carbohydrate is dextrose.

19. The method according to claim 4 wherein the carbohydrate comprises non-reducing sugars that may produce reducing sugars in situ.

20. The method according to claim 12 wherein the carbohydrate-based binder is obtained from a carbohydrate-based binder composition comprising a carbohydrate component and a cross-linker and, optionally, a reaction product of the carbohydrate component and the cross-linker, wherein the cross-linker is an ammonium salt of an inorganic acid selected from ammonium sulphate and ammonium phosphate.

21. The method according to claim 12 wherein the carbohydrate-based binder is obtained from a carbohydrate-based binder composition comprising a carbohydrate component and a cross-linker and, optionally, a reaction product of the carbohydrate component and the cross-linker, wherein the cross-linker is a polycarboxylic acid, ammonium salts thereof, ester or anhydride derivatives thereof.

22. The method according to claim 12 wherein the carbohydrate is selected from monosaccharides, disaccharides, oligosaccharides and polysaccharides and/or combinations thereof, wherein non-reducing sugars may produce reducing sugars in situ, and wherein the level of C5-sugars or five-membered ring sugars varies from 10 to 70 wt. %.

23. The method according to claim 12 wherein the carbohydrate-based binder composition comprises a carbohydrate component and a cross-linker and, optionally, a reaction product of the carbohydrate component and the cross-linker, wherein the carbohydrate component is present in an amount ranging from 30% to less than 95% by dry weight of the binder composition and the crosslinker makes up 5% to less than 50% by dry weight of the binder composition.

24. The method according to claim 13 wherein the carbohydrate component is present in an amount ranging from 60% to less than 95% by dry weight of the binder composition and the crosslinker makes up 5% to less than 40% by dry weight of the binder composition.

Description

[0041] FIG. 1 is a chart showing the variation of furfural content in a binder derived from a carbohydrate component comprising dextrose and xylose in varying amounts, cross-linked with ammonium sulphate, as well as the effect of added hexamethylenediamine.

EXAMPLE 1

[0042] Dextrose and varying amounts of xylose were dissolved in water to constitute different carbohydrate components. These carbohydrate components were combined with ammonium sulphate cross-linker (AMS) to form aqueous binder compositions at a dry weight ratio of carbohydrate/AMS of 85/15 and at 37.5 wt. % solids. The same procedure was repeated with binder compositions as above further comprising 2 and 4 wt. % hexamethylene diamine. GFA glass filters were impregnated with the relevant binders at a rate of 15% by weight cured solids, and cured during 5 min at 180? C.

[0043] The furfural concentration of the cured binder was determined by leaching the impregnated filter into a small quantity of water at room temperature for 1 hour and analysing the leachate for furfural and hydroxyfurfural by HPLC (C18 column, acetonitrile/water mobile phase, UV detector). The results were plotted in a chart as per FIG. 1 which clearly shows that addition of small amounts of hexamethylene diamine significantly depresses furfural generation.

EXAMPLE 2

[0044] The same experiment as above was repeated for the compositions shown in the Tables below, in comparison with corresponding compositions containing no amine.

[0045] As can be understood, added urea, lysine and some further polyamines efficiently reduce furfural concentration in the leachate.

TABLE-US-00001 TABLE 1 Furfural reduction in 85/15 glucose/(NH.sub.4).sub.2SO.sub.4 binder compositions % Reduction in % Reduction in Furfural + Furfural + Amine 2% amine 4% amine HMDA 8% 95% Lupasol FG 9% 48% Urea 36% 47% TETA 16% 46% Triethylenetetramine Lysine 7% 22% Luredur VM 0% 16% Ethylamine 0% 0% Jeffamine T-403 0% 0%

TABLE-US-00002 TABLE 2 Furfural reduction in 85/15 sugar/(NH.sub.4).sub.2SO.sub.4 binder compositions, wherein the sugar composition comprises 60% wt. glucose and 40% wt. xylose. % Reduction in % Reduction in Furfural + Furfural + Amine 2% amine 4% amine HMDA 27% 98% Lysine 16% 29% TETA 15% 26% Triethylenetetramine Lupasol FG 6% 23% Urea 12% 22% Jeffamine T-403 9% 19% Ethylamine 2% 18% Luredur VM 0% 6%

[0046] In the Tables above,

[0047] HMDA stands for hexamethylenediamine

[0048] Lupasol FG (commercial name) is a polyethylenimine

[0049] Jeffamine T-403 (commercial name) is a polyetheramine

[0050] Luredur VM (commercial name) is a polyvinylamine