CARBOHYDRATE BASED BINDER SYSTEM AND METHOD OF ITS PRODUCTION

Abstract

The present invention relates to an aqueous carbohydrate based binder composition, comprising a carbohydrate component and an amine component, wherein the carbohydrate component comprises one or more pentose sugars, as well as to a method of its production.

Claims

1. An aqueous binder composition, comprising a carbohydrate component (a) and an amine component (b), wherein the carbohydrate component (a) comprises one or more pentose(s) in a total amount of 3 to 70 mass %, based on the mass of the total carbohydrate component (a).

2. The binder composition according to claim 1, wherein the carbohydrate component (a) further comprises one or more hexose(s) in a total amount of 97 to 30 mass %, based on the mass of the total carbohydrate component (a).

3. The binder composition according to claim 1, wherein the one or more pentose(s) is/are selected from the group consisting of xylose, arabinose, ribose, lyxose, ribulose and xylulose, or any combination thereof.

4. The binder composition according to claim 1, wherein the amine component (b) is selected from the group consisting of proteins, peptides, amino acids, organic amines, polyamines, ammonia, ammonium salts of a monomeric polycarboxylic acid, ammonium salts of a polymeric polycarboxylic acid, and ammonium salts of an inorganic acid, or any combination thereof.

5. The binder composition according to claim 1, wherein said binder composition further comprises an amino acid component (c).

6. A binder obtainable by heating the binder composition according to claim 1.

7. A method of producing an aqueous binder composition, comprising a carbohydrate component (a) and an amine component (b), wherein the carbohydrate component (a) comprises one or more pentose(s) in a total amount of 3 to 70 mass %, based on the mass of the total carbohydrate component (a), wherein the method comprises the steps: (i) hydrolyzing one or more cellulose-based carbohydrate source(s), (ii) isolating the carbohydrates from the one or more hydrolized cellulose-based carbohydrate source(s), (iii) using the isolated carbohydrates from the one or more cellulose-based carbohydrate source(s) to form a carbohydrate component (a), comprising one or more pentose(s) in a total amount of 3 to 70 mass %, based on the mass of the total carbohydrate component (a), and (iv) adding an amine component (b).

8. The method according to claim 7, wherein step (i) of hydrolyzing one or more cellulose-based carbohydrate source(s) independently comprises treatment with heat/pressure, enzymatic and/or acidic treatment and/or metal chloride hydrolysis of each of said one or more cellulose-based carbohydrate source(s).

9. The method according to claim 7, wherein the carbohydrate component (a) further comprises one or more hexose(s) in a total amount of 97 to 30 mass %, based on the mass of the total carbohydrate component (a).

10. The method according to claim 7, wherein the one or more pentose(s) is/are selected from the group consisting of xylose, arabinose, ribose, lyxose, ribulose and xylulose, or any combination thereof.

11. The method according to claim 7, wherein the one or more cellulose-based carbohydrate source(s) are selected from the group consisting of agricultural residues such as corn stover and sugarcane bagasse; dedicated energy crops such as sugar beet, switchgrass, Miscanthus, hemp, willow and corn; wood residues, such as wood chips, timber barc, saw mill discards and paper mill discards; municipal paper waste, such as used paper and low grade paper waste; as well as industrial cellulose sources, such as brewery waste and dairy products.

12. The method according to claim 7, wherein the amine component (b) is selected from the group consisting of proteins, peptides, amino acids, organic amines, polyamines, ammonia, ammonium salts of a monomeric polycarboxylic acid, ammonium salts of a polymeric polycarboxylic acid, and ammonium salts of an inorganic acid, or any combination thereof.

13. The method according to claim 7, wherein step (iii) of forming the carbohydrate component (a) includes combining carbohydrates and/or carbohydrate mixtures obtained from at least two different cellulose-based carbohydrate sources.

14. The method according to claim 7, wherein said binder composition further comprises an amino acid component (c).

15. The method according to claim 14, wherein said amino acid component (c) is formed by using amino acids obtained from step (i) of hydrolyzing one or more cellulose-based carbohydrate source(s).

16. A method of manufacturing a product selected from the group consisting of: mineral wool insulation, glass wool insulation, stone wool insulation, a collection of fibers, a collection of particles, a collection of cellulose containing particles or fibers, a wood board, an orientated strand board, a wood particle board, plywood, an abrasive, a non-woven fiber product, a woven fiber product, a foundry mould, a refractory product, a briquette, a friction material, a filter, and an impregnated laminate comprising the steps of: applying to non- or loosely assembled matter a binder in accordance with claim 1; and curing the binder.

Description

[0054] The figures show:

[0055] FIG. 1 shows a diagram wherein cure rate of various binder compositions is related to the carbohydrate composition thereof with respect its pentose/hexose content.

[0056] FIG. 2 shows a diagram of different cure rates obtained from various xylose-containing binder compositions.

[0057] FIG. 3 shows laboratory cure rates obtained with binders using different proportions of glucose and xylose as the carbohydrate component of a binder and ammonium sulphate as the amine component.

[0058] The binder system of the present invention is free of environmentally problematic reactants/products and is particularly formaldehyde-free, and at the same time shows excellent cure rates which enable the reduction of cure time or cure temperature, thus providing a more efficient production, e.g. of fiber-based products such as glass or rock wool. In addition, as a further ecologically valuable asset, the binder system of the present invention may be produced by a method according to which cellulose-based, and thus renewable carbohydrate sources are used for preparing the carbohydrate component of said binder composition. Said cellulose-based carbohydrate sources may be energy plants known to contain high amounts of cellulose, or cellulose-containing wastes of all sorts, such as (low grade) paper waste, or waste incurred during industrial paper production.

[0059] The following examples are intended for further illustration without intention to limit the subject matter of the present invention.

EXAMPLES

Example 1

Cure Rates of Xylose-Containing Binder Compositions Using Hexamethylenediamine (HMDA)

[0060] Aqueous binder compositions were prepared according to the formulations provided in Table 1, below. The overall compositions are based on 80 mass % sugars +20 mass % hexamethylenediamine, calculated solids 70 mass %.

TABLE-US-00001 TABLE 1 Formulations Gelling (mass % of pentose in time Components (g) brackets) (s) HMDA DMH Xylose Water Mannose Arabinose DMH 851 10.00 30.80 9.20 DMH + Xylose 528 10.18 27.43 2.94 9.45 (9.68) DMH + Xylose 451 10.36 23.94 5.99 9.71 (20.01) DMH + Xylose 359 10.56 20.32 9.15 9.97 (31.05) DMH + Xylose 305 10.69 16.47 12.54 10.30 (43.23) DMH + Xylose 286 10.96 12.66 15.82 10.56 (55.55) DMH + Xylose 266 11.14 8.58 19.40 10.87 (69.34) DMH + Xylose 251 11.40 4.39 23.03 11.18 (83.99) Xylose 11.49 26.95 11.49 (100.00) DMH + 380 10.56 10.16 9.15 10.85 9.33 Xylose + Mannose (31.95) Arabinose + 286 11.17 8.60 6.45 10.87 12.90 DMH + Xylose (69.23)

[0061] The ratios pentose versus hexose were calculated on a molarity basis (with the content in mass % of the pentose(s) provided in brackets), and the calculated solids were kept the same to allow a like for like comparison of the formulations.

[0062] The two last formulations containing sugar mixtures reflect typical carbohydrate mixtures obtained when hydrolyzing soft wood and sugar beet. As can clearly be taken from the graph in FIG. 1, the presence of a pentose (here: xylose or a mixture of xylose/arabinose) significantly improves the cure rate achieved with the resulting binder composition. However, surprisingly, there is no linear relation between the pentose content and improvement in cure rates, and the effect attenuates when adding great excesses of xylose. Accordingly, the amount of pentose in the carbohydrate component should be adjusted to optimize cure speed.

[0063] When replacing half of the hexose DMH (dextrose monohydrate) in a DMH and xylose composition with the hexose mannose, which has a similar structure when compared to dextrose, said mixture results in a similar curing kinetic when compared to the above-mentioned composition comprising DMH and xylose.

[0064] Also, replacing parts of the xylose with another pentose (arabinose) results in similar curing kinetics when compared to the composition containing only xylose.

Example 2

Cure Rates of Xylose-Containing Binder Compositions Using (NH.SUB.4.).SUB.2.SO.SUB.4

[0065] Three aqueous binder compositions (up to 100 mL) were prepared according to the formulations provided in Table 2, below.

TABLE-US-00002 TABLE 2 85.3% Glucose + 46.6% Glucose + 0.8% Xylose + 38.4% Xylose + 83.7% Xylose + 13.9% 15.0% 16.3% Formulations (NH.sub.4).sub.2SO.sub.4 (NH.sub.4).sub.2SO.sub.4 (NH.sub.4).sub.2SO.sub.4 Glucose (g) 16.20 8.20 Xylose (g) 0.15 6.75 13.51 (NH.sub.4).sub.2SO.sub.4 (g) 2.64 2.64 2.64

[0066] These formulations were dropped on filter pads and heated at 140 C. Brown polymers were formed on the filter pads, then dissolved in water and absorbance of the solutions was measured to build the cure rates of each formulation over time.

[0067] The resulting cure rates can be taken from FIG. 2, from which it is apparent that small (catalytic) amounts of a pentose are not sufficient to significantly accelerate the cure rate.

Example 3

Cure Rates of Glucose-Xylose Containing Binder Compositions Using (NH.SUB.4.).SUB.2.SO.SUB.4

[0068] The cure rate of the following formulations of binders was tested in the laboratory:

TABLE-US-00003 Sample A B C D E F Molar % 100 85 70 50 30 0 glucose Molar % 0 15 30 50 70 100 xylose Actual weight 0% 12.82% 26.32% 45.45% 66.04% 100% % of Xylose Weight 4.50 3.83 3.15 2.25 1.35 0.00 glucose (g) Weight 0.00 0.56 1.13 1.88 2.63 3.75 xylose (g) Weight of 4.95 4.21 3.47 2.48 1.49 0.00 DMH required (g) Ammonia 0.50 0.50 0.50 0.50 0.50 0.50 Sulphate (g) Total solids 5.00 4.89 4.78 4.63 4.48 4.25 weight (g) Water (g) 13.05 13.12 13.18 13.27 13.36 13.50 Total batch 18.50 18.39 18.28 18.13 17.98 17.75 weight (g)

[0069] The results are shown in FIG. 3 which plots light absorbance at 470 nm or each sample being cured (y-axis) against time T in minutes (x-axis). It is interesting to note that Sample D (about 45% wt. xylose and 55% wt. glucose; about 50% mol xylose and 50% mol glucose) gave a cure rate similar to 100% xylose; this indicates a synergy between xylose and glucose and, more generally, between pentose(s) and hexose(s) in binders disclosed herein.