IMPROVED BINDER COMPOSITIONS AND USES THEREOF

Abstract

The present invention relates to new aqueous binder compositions comprising an aqueous curable binder composition comprising starting materials required for forming a thermoset resin upon curing and a matrix polymer, wherein the starting materials required for forming a thermoset resin upon curing comprise (i) a polyhydroxy component and a polycarboxylic acid component, or an anhydride, ester or salt derivative thereof and/or reaction product thereof, or (ii) a carbohydrate component and a nitrogen containing component and/or a reaction product thereof.

Claims

1. An aqueous curable binder composition comprising starting materials required for forming a thermoset resin upon curing and a matrix polymer, wherein the starting materials required for forming a thermoset resin upon curing comprise (i) a polyhydroxy component and a polycarboxylic acid component, or an anhydride, ester or salt derivative thereof and/or reaction product thereof, or (ii) a carbohydrate component and a nitrogen containing component and/or a reaction product thereof, and wherein the matrix polymer is selected from cellulose, starch, alginate, hyaluronic acid, and their derivatives, starch derivatives or copolymers, carboxymethyl cellulose (CMC), sodium carboxymethyl cellulose (NaCMC), hydroxypropyl cellulose (HPC), 2-hydroxyethyl cellulose (HEC), chitosan, polyvinyls (polyvinyl alcohol (PVA), polyvinyl acetate (PVAc), partially hydrolyzed polyvinyl acetate, polyacrylonitrile (PAN)), polyacrylics, polyacrylate, polymethacrylate, polyacrylamide, polymethacrylamides, polyurethanes, polyesters, aliphatic isocyanate oligomers, azetidinium polymer, copolymers thereof and mixtures thereof.

2. The aqueous curable binder composition of claim 1 wherein the polycarboxylic acid component is selected from monomeric and polymeric polycarboxylic acids.

3. The aqueous curable binder composition of claim 2 wherein the polycarboxylic acid component is a monomeric polycarboxylic acid, such as dicarboxylic acid, including, but not limited to, unsaturated aliphatic dicarboxylic acids, saturated aliphatic dicarboxylic acids, aromatic dicarboxylic acids, unsaturated cyclic dicarboxylic acids, saturated cyclic dicarboxylic acids, hydroxy-substituted derivatives thereof, or, tricarboxylic acid, including, but not limited to, unsaturated aliphatic tricarboxylic acids, saturated aliphatic tricarboxylic acids, aromatic tricarboxylic acids, unsaturated cyclic tricarboxylic acids, saturated cyclic tricarboxylic acids, hydroxy-substituted derivatives thereof, preferably citric acid, and mixtures thereof.

4. The aqueous curable binder composition of claim 1 wherein the salt derivative of the polycarboxylic acid component is an ammonium salt.

5. The aqueous curable binder composition of claim 1 wherein the polyhydroxy component is a carbohydrate component selected from monosaccharide in its aldose or ketose form, including a triose, a tetrose, a pentose, a hexose, or a heptose; or an oligosaccharide or polysaccharide; or a component that yields one or more reducing sugars in situ, or combinations thereof.

6. The aqueous curable binder composition of claim 1 wherein the nitrogen containing component is an ammonium salt of an inorganic acid, selected from phosphoric, sulphuric, nitric and carbonic acid, preferably ammonium sulphate or ammonium phosphate.

7. The aqueous curable binder composition of claim 1 wherein the nitrogen containing component is selected from polyamine functional compounds comprising primary and/or secondary and/or tertiary and/or quaternary amine functional groups.

8. The aqueous curable binder composition of claim 7 wherein the polyamine functional compound has the formula of H.sub.2N-Q-NH.sub.2, wherein Q is an alkylene, cycloalkylene, heteroalkylene, or cycloheteroalkylene, each of which optionally substituted.

9. The aqueous curable binder composition of claim 7 wherein the polyamine functional compound is selected from di-amine, tri-amine, tetra-amine, and pentaamine, more specifically 1,6-diaminohexane and 1,5-diamino-2-methylpentane, diethylenetriamine, 1-piperazine-ethaneamine, and bis(hexamethylene)triamine, triethylenetetramine, tetraethylenepentamine, polyethyleneimine (PEI), polyvinyl amine, polyether amine, polylysine.

10. The aqueous curable binder composition of claim 1 wherein the matrix polymer is selected from cellulose derivatives, such as carboxymethyl cellulose (CMC), sodium carboxymethyl cellulose (NaCMC), hydroxypropyl cellulose (HPC), 2-hydroxyethyl cellulose (HEC); nanocellulose, polyvinyl acetate (PVAc), aliphatic isocyanate oligomers, chitosan, azetidinium polymer or mixtures thereof.

11. The aqueous curable binder composition of claim 1 wherein the matrix polymer shows a molecular weight ranging from 500 Daltons (Da) to 210.sup.6 Da, preferably from 110.sup.3-510.sup.5 Da, more preferably from 510.sup.4 Da-310.sup.5 Da.

12. The aqueous curable binder composition of any of the claim 1 wherein the dry weight ratio of carbohydrate to ammonium salt of inorganic or polycarboxylic acid or polyamine functional compound ranges from about 2 to about 35, preferably from about 2.5 to about 13.

13. The aqueous curable binder composition of claim 12 wherein the matrix polymer makes up from about 1 to 20% of the dry weight of the binder composition, preferably from about 2 to 18% dry weight, more preferably from 5 to 15% dry weight of the composition.

14. The aqueous curable binder composition of any of the claim 1 further comprising dyes, antifungal agents, antibacterial agents, hydrophobes, silicone containing coupling agents and/or other additives known in the art for such binder compositions.

15. The aqueous binder composition of any of the preceding claim 1 wherein a component is selected micro-/or nano-particles derived from natural or synthetic polymers or their combination such as nanocelluloses, or from inorganic materials such as MgO, CaO, Al.sub.2O.sub.3 and CaCO.sub.4, or nanoclays such as montmorillonite, bentonite, kaolinite, hectorite, and halloysite and other organically-modified nanoclays, and/or mixtures thereof.

16. An assembly of fibers or particles bonded with an aqueous curable binder composition according to claim 1 or with a binder resulting from the curing of any of the curable binder compositions of claim

17. The assembly of fibers according to claim 16 being an insulation product, such as a mineral wool mat or other.

18. The assembly of particles according to claim 16 being a composite wood board, such as wood fiber board, wood particle board, plywood or similar board.

19. A process for the manufacturing of an assembly of fibers or particles according to claim 17 characterized in that it comprises the successive or concomitant application of the relevant components of the aqueous curable binder composition of claim 1, or the application of an aqueous binder composition according to claim 1 onto a collection of fibers or particles; the gathering of the coated fibers or particles in an assembly; and curing, whereby the components of the aqueous curable binder composition are caused to react to form a macromolecular binder, and evaporating water.

20. The process according to claim 19 characterized in that curing is performed at a temperature ranging from 90 C.-200 C., preferably higher than 140 C., more preferably lower than 190 C., typically between 160 and 180 C.

21. The process according to claim 19 characterized in that the aqueous binder composition is applied by spraying onto the collection of fibers or particles.

22. The process of claim 19 wherein the assembly is a wood fiber board or wood particle board or similar wood board, subjected to pressing during curing.

Description

[0049] The invention will be explained in more details in the examples below with reference to the attached Figures, in which:

[0050] FIGS. 1-3 show the cure rate of several binder compositions;

[0051] FIG. 4 shows the bond strength before and after weathering for dextrose/ammonium sulphate/polymer based binder compositions;

[0052] FIG. 5 shows the bond strength before and after weathering for dextrose/citric acid/polymer based binder compositions; and

[0053] FIGS. 6 and 7 show the bond strength before and after weathering for dextrose/diammonium phosphate/polymer based binder compositions.

[0054] In the following, examples, the following matrix polymers have been used: [0055] Carboxymethyl cellulose (Na CMC)-M.sub.W of approx. 250 kDa [0056] Hydroxypropyl cellulose (HPC)-M.sub.W of approx. 100 kDa [0057] Hydroxyethyl cellulose (HEC)-M.sub.W of approx. 250 kDa [0058] Chitosan (CS)-Mw in the range 60 kDa-220 kDa [0059] Partially hydrolysed PVA- M.sub.W in the range of 30 kDa-70 kDa.

Preparation of Binder Compositions

[0060] The required amount of matrix polymer was dissolved in water. Similarly, the required amount of dextrose monohydrate (DMH) was dissolved in water separately, followed by addition of ammonium sulphate (AmSO4), diammonium phosphate (DAP) or citric acid monohydrate (CAMH) with constant stirring, as the case may be. Then the desired amount of polymer solution was added to the mixture of DMH solution or vice versa. The mixture was vigorously stirred in order to obtain a homogenous solution, followed by addition of other additives into the solution if applicable and vigorous stirring.

Determination of Cure Rate

[0061] A 50 L sample of binder solution was dispensed onto a spot of a Whatman glass microfiber filter surface. Samples were kept on the top shelf in an oven, avoiding high moisture content inside the oven during curing. For each binder solution, samples were cured for different time periods ranging from 1 minute up to 20 minutes, at different temperatures. After curing, each glass filter sample was cut and fully immersed in 50 mL cold water in a 150 mL glass beaker, and then sonicated for 15 minutes at room temperature. The extract solution was filtered and the absorbance of the extract was determined with a spectrophotometer at 470 nm. The absorbance was plotted as a function of cure time. The results of various binder compositions are presented in FIGS. 1-3. As shown in FIG. 1, the matrix polymer addition to DMH/AmSO4 binder compositions shows no significant effect on the cure rate. The addition of matrix polymer to CAMH based binder compositions (FIG. 2) and DAP based binder compositions (FIG. 3) accelerated curing as demonstrated in FIGS. 2 and 3.

Determination of Bond Strength Before and After Weathering

[0062] Commercial PF (phenol formaldehyde) impregnated (A4 size) glass fiber veils were placed into a muffle furnace oven for 30 minutes at 600 C. in order to burnout the PF binder, and were then allowed to cool for 30 minutes. The obtained veil samples were weighted.

[0063] Approx. 400 g binder solution samples were poured into dip trays, and the obtained veil samples carefully fully immersed into the relevant binder solutions. The impregnated veils were cured at desired temperature for desired periods of time. Binder content was then measured and bond strength determined as follows.

[0064] The bond strength of the relevant cured binder impregnated veils was determined by means of a testometric machine (M350-10CT). For each test a cured binder impregnated A4 veil was cut into 8 equal strips. Each strip was tested separately using a 50 Kg load cell (DBBMTCL-50 kg) at an automated test speed of 10 mm/min controlled by winTest Analysis software. Glass veil tensile plates were attached to the testometric machine in order to ensure a 100 mm gap between plates. Samples were placed vertically in the grippers; and the force was tarred to zero. Various parameters such as maximum load at peak, stress at peak and modulus (stiffness) were evaluated by the software, and data presented as an average of 8 samples with standard deviation. The average maximum load at peak or stress at peak defined as the bond strength.

[0065] Cured binder impregnated veils were placed in an autoclave (J8341, Vessel: PVO2626 with associated safety valve, door interlock and integrated pipework) system. Samples were treated at 90% humidity and at a temperature ranging from 40 C. to 110 C. (full cycle), at a pressure of up to 2.62 bar, for 3 hours. The samples were dried completely in order to ensure no moisture remains onto the veils. The autoclave treated samples were tested for bond strength by means of testometric machine (M350-10CT) described here above, and the results were compared with those of untreated samples.

[0066] The evaluation of bond strength was investigated for the veils impregnated with various binder compositionssee FIGS. 4-7. These impregnated veils were cured at 190 C. for 20 minutes and mechanical tests were performed at dry conditions.

[0067] In FIG. 4, the results for the following binder compositions are shown: DMH/AmSO4/CS, DMH/AmSO4/NaCMC and DMH/AmSO4/PVA. The bond strength was found to be 66N for DMH/AmSO4 (85/15), when CS was added into the binder composition, the bond strength increased significantly. More specifically, the bond strength increased to 96N for DMH/AmSO4/CS (74/13/13) which is 45% higher bond strength as compared to that of DMH/AmSO4(85/15) binder (FIG. 4a). Similarly the bond strength of DMH/AmSO4/NaCMC (particularly for the ratios of 74/13/13, 85/15/10 and 85/15/5) was higher than for DMH/AmSO4 (85/15) (FIG. 4c). In the figures, the values presented in each graph are average values for the corresponding formulations. The dotted lines represent bond strength of binder composition containing no additional matrix polymer.

Bond Strength After Weathering was not Significantly Increased by Addition of Matrix Polymer.

[0068] FIG. 5 shows the bond strength results of various DMH/CAMH/NaCMC binder compositions impregnated into glass fiber veils. When NaCMC (5%) was added into the citric acid based composition, the bond strength increased by 23% (FIG. 5). Increase of the NaCMC concentration in the binder composition (DMH/CAMH/NaCMC) does not significantly affect the bond strength.

[0069] FIG. 6 shows the bond strength before and after extreme weather treatment. The study was performed with 7% DAP, and the ratio of DMH/polymer was varied. Results (FIG. 6) indicate the bond strength of DMH/DAP (93/7) is increased by addition of CMC or CS matrix polymer. When adding more matrix polymer into the binder composition (93/7), the bond strength remains essentially steady within the range.

[0070] The weather stability bond strength of all these DMH/DAP/NaCMC and DMH/DAP/CS compositions was also investigated, and the results are plotted in FIG. 6 too. Results indicate that CS significantly increases the weather stability (compare DMH/DAP/CS to DMH/DAP (93/7)).

[0071] FIG. 7 shows the bond strength of DMH/DAP/Polymer compositions before and after full cycle autoclaving: (a) DMH/DAP/NaCMC, (b) DMH/DAP/PVA and (c) DMH/DAP/CS. The values presented in each graph are the average values of the corresponding compositions. The DAP concentration was kept constant (12-13%). Results indicate that both NaCMC and CS significantly increase the bond strength as well as improved the weather stability as compared to that of DMH/DAP (87/13).

Binder Weight Loss Upon Curing

[0072] Binder solutions were prepared as described above and weighted samples showing a solids content of 2-5% were poured into aluminium petri dishes and kept in an oven for 2 hours at 140 C. The theoretical and experimental values were determined and the weight loss was calculated. The results obtained for various compositions are shown in Table 1 below. As can be seen, the binder weight loss is significantly reduced with addition of matrix polymer in the compositions.

TABLE-US-00001 TABLE 1 Binder weight loss upon curing at 140 C. for 2 hours. Binder Weight Formulations (wt. %) Loss (%) 85% DMH + 15% AmSO4 31.52 80% DMH + 15% AmSO4 + 5% NaCMC 22.76 75% DMH + 15% AmSO4 + 10% NaCMC 16.67 70% DMH + 15% AmSO4 + 15% NaCMC 8.46 80% DMH + 15% AmSO4 + 5% CS 26.76 80% DMH + 15% AmSO4 + 5% PVA 21.65 85% DMH + 15% CAMH 32.75 80.75% DMH + 14.25% CAMH + 5% NaCMC 23.98 80.75% DMH + 14.25% CAMH + 5% PVA 24.72 78.2% DMH + 13.8% CAMH + 8% NaCMC 23.59 78.2% DMH + 13.8% CAMH + 8% PVA 24.68 85% DMH + 15% CAMH 32.75 87% DMH + 13% DAP 32.44 80% DMH + 12% DAP + 8% NaCMC 27.27 80% DMH + 12% DAP + 8% PVA 29.37 82.65% DMH + 12.35% DAP + 5% CS 27.97

Water Absorption

[0073] 100 g of binder solutions were prepared with desired solid content. Glass microfiber filter GFA were completely immerged and kept for 10 seconds in the relevant binder solutions, and then removed. The binder impregnated GFA samples were cured at desired temperatures, e.g. at 180-190 C. for 10 minutes, and the weight was measured (4 decimal point). Thereafter, the cured GFA samples were fully immerged into a beaker filled with 200 mL water. The samples were maintained for 1 hour under water by means of a glass rod. After 1 hour, the GFA samples were withdrawn and the surface water was absorbed by absorbent paper. The weight of the wet GFA sample was measured. The percentage of water absorption was determined for each sample in three replicates according to the following relationship.

[0074] % Water absorption=[(Mass of GFA wetMass of GFA dry)/Mass of GFA dry]100

[0075] Table 2 represents water absorption (%) for various compositions of DMH/AmSO4/Polymer, DMH/CAMH/Polymer and DMH/DAP/Polymer, with and without additive (silicone). It can be seen that water absorption is about 247% for standard known DMH/AmSO4 (85/15) binder. With the addition of matrix polymer such as NaCMC and CS the water absorption is significantly reduced, depending on the type and ratio of the matrix polymer used in the formulation. The addition of silicone (1% or 1.5%) in the composition further reduces water absorption significantly.

TABLE-US-00002 TABLE 2 Water absorption (%) of DMH/AmSO4/Polymer, DAP/CAMH/Polymer and DMH/DAP/Polymer binders. Water Absorption STDEV (%) (+/) DMH/AmSO4/Polymer Formulation DMH/AmSO4: 85/15 246.64 6.37 DMH/AmSO4/NaCMC: 85/15/5 210.32 0.47 DMH/AmSO4/NaCMC/Silicone: 85/15/5/1 144.85 10.49 DMH/AmSO4/NaCMC/Silicone: 85/15/5/1.5 115.36 5.71 DMH/AmSO4/NaCMC/Silicone: 85/15/5/3.0 109.47 1.36 DMH/AmSO4/NaCMC: 85/15/10 153.05 7.36 DMH/AmSO4/NaCMC/Silicone: 85/15/10/1 134.75 3.52 DMH/AmSO4/NaCMC/Silicone: 85/15/10/1.5 112.97 8.42 DMH/AmSO4/NaCMC/Silicone: 85/15/10/3.0 119.52 10.96 DMH/AmSO4/NaCMC 74/13/13 112.67 7.77 DMH/AmSO4/NaCMC/Silicone: 74/13/13/1 130.45 6.55 DMH/AmSO4/NaCMC/Silicone: 74/13/13/1.5 116.80 9.78 DMH/AmSO4/NaCMC/Silicone: 74/13/13/3.0 143.62 1.66 DMH/AmSO4/CS: 85/15/5 198.62 8.98 DMH/AmSO4/CS/Silicone: 85/15/5/1 76.92 0.97 DMH/AmSO4/CS: 85/15/10 145.25 5.78 DMH/AmSO4/CS/Silicone: 85/15/10/1 82.65 4.73 DMH/AmSO4/CS/Silicone: 85/15/10/1.5 79.76 0.56 DMH/CAMH/Polymer Formulation DMH/CAMH: 85/15 273.55 5.39 DMH/CAMH/NaCMC: 80.75/14.25/5 224.65 8.30 DMH/CAMH/NaCMC/Silicone: 80.75/14.25/5/1 76.33 4.43 DMH/CAMH/NaCMC: 78.2/13.8/8 190.18 12.62 DMH/CAMH/NaCMC/Silicone: 78.2/13.8/8/1 83.97 6.38 DMH/CAMH/NaCMC: 74/13/13 143.25 17.68 DMH/CAMH/NaCMC/Silicone: 74/13/13/1 125.34 3.57 DMH/CAMH/HEC: 74/13/13 198.23 7.78 DMH/CAMH/HEC/Silicone: 74/13/13/1 77.25 6.39 DMH/CAMH/HEC/Silicone: 74/13/13/3 76.35 7.56 DMH/DAP/Polymer Formulation DMH/DAP: 87/13 261.61 4.62 DMH/DAP/NaCMC: 80/12/8 203.96 7.37 DMH/DAP/PVA: 80/12/8 231.99 10.75

[0076] Binder solutions comprising 2% solids were prepared according to the method disclosed above and showed the compositions indicated in the tables below. Bond strength of weathered and unweathered veils impregnated with the relevant binder compositions and cured for 8 minutes at 200 C. were measured as disclosed above. The results are summarized in the tables below, averaged over 8 replicates.

TABLE-US-00003 TABLE 3 Bond strength of veils, Bond strength after unweathered weather treatment Average Bond STDEV Average Bond STDEV Binder Formulations Strength (N) (+/) Strength (N) (+/) 85% DMH + 15% 63.347 10.896 36.847 7.001 AmSO4 (control) 84% DMH + 15% 63.930 4.880 36.278 4.683 AmSO4 + 1% CS 83% DMH + 15% 71.741 9.679 40.750 11.168 AmSO4 + 2% CS 82% DMH + 15% 73.794 7.956 41.389 6.299 AmSO4 + 3% CS 81% DMH + 15% 74.638 3.456 42.615 4.071 AmSO4 + 4% CS 80% DMH + 15% 78.263 7.636 45.519 7.849 AmSO4 + 5% CS

TABLE-US-00004 TABLE 4 Bond strength of veils, Bond strength after unweathered weather treatment Average Bond STDEV Average Bond Binder Formulations Strength (N) (+/) Strength (N) STDEV (+/) 49.73% DMH + 35.28% Fructose + 65.56 8.86 49.13 12.91 15% AmSO4 (control) 49.14% DMH + 34.16% 77.22 8.04 56.87 10.69 Fructose + 15% AmSO4 + 1% CS 48.56% DMH + 34.44% Fructose + 80.63 5.39 53.80 9.84 15% AmSO4 + 2% CS 47.97% DMH + 34.03% Fructose + 89.95 8.92 55.39 7.74 5% AmSO4 + 3% CS 47.39% DMH + 33.61% Fructose + 90.35 10.59 55.46 5.87 15% AmSO4 + 4% CS 46.8% DMH + 33.2% Fructose + 93.36 10.44 55.45 4.20 15% AmSO4 + 5% CS

TABLE-US-00005 TABLE 5 Bond strength of Bond strength after weather veils unweathered treatment Average Bond Average Bond Binder Formulations Strength (N) STDEV (+/) Strength (N) STDEV(+/) 93% DMH + 7% DAP (control) 61.879 5.623 47.517 7.113 92% DMH + 7% DAP + 1% CS 76.365 11.618 62.671 7.041 91% DMH + 7% DAP + 2% CS 77.228 19.285 71.698 9.090 90% DMH + 7% DAP + 3% CS 80.586 7.494 65.023 6.975 89% DMH + 7% DAP + 4% CS 83.593 3.745 63.070 6.317 88% DMH + 7% DAP + 5% CS 85.106 8.047 68.655 5.123 87% DMH + 13% DAP 63.593 3.692 56.608 7.624 86% DMH + 13% DAP + 1% CS 83.311 4.994 56.714 9.745 85% DMH + 13% DAP + 2% CS 82.974 7.375 68.743 9.176 84% DMH + 13% DAP + 3% CS 91.810 13.908 74.988 6.892

[0077] The data clearly shows the beneficial effect of chitosan polymer matrix (CS) addition to the hydrocarbon based binder compositions.

[0078] The experiments were repeated with binder compositions comprising 2% solids. The compositions are shown in the tables below and comprise a polyazetidinium (CA1025) as polymer matrix. Bond strength of weathered and unweathered veils impregnated with the relevant binder compositions and cured for 8 minutes at 200 C. were measured as disclosed above. The results are summarized in Table 6 below, averaged over 8 replicates.

TABLE-US-00006 TABLE 6 Bond strength of veils Bond strength after unweathered weather treatment Average Bond STDEV Average Bond STDEV Binder Formulations Strength (N) (+/) Strength (N) (+/) 85% DMH + 15% AmSO4 66.812 4.145 52.123 4.542 84% DMH + 15% AmSO4 + 1% CA1025 76.345 11.167 63.410 5.393 83% DMH + 15% AmSO4 + 2% CA1025 91.245 6.388 60.231 10.250 82% DMH + 15% AmSO4 + 3% CA1025 86.144 8.922 61.076 13.230 81% DMH + 15% AmSO4 + 4% CA1025 85.144 11.654 59.530 6.549 80% DMH + 15% AmSO4 + 5% CA1025 90.640 15.134 59.614 4.720 85% DMH + 15% CAMH 84.766 6.047 59.569 10.650 84% DMH + 15% CAMH + 1% CA1025 116.151 8.766 103.040 15.460 83% DMH + 15% CAMH + 2% CA1025 113.480 12.390 99.004 19.273 82% DMH + 15% CAMH + 3% CA1025 108.101 9.386 93.758 14.468 81% DMH + 15% CAMH + 4% CA1025 113.229 11.863 96.023 11.444 93% DMH + 7% DAP 73.499 6.763 61.000 10.738 92% DMH + 7% DAP + 1% CA1025 76.266 9.219 65.361 12.090 91% DMH + 7% DAP + 2% CA1025 86.489 5.461 68.984 10.122 90% DMH + 7% DAP + 3% CA1025 87.264 10.278 69.571 9.345 89% DMH + 7% DAP + 4% CA1025 87.280 6.899 66.944 8.225 87% DMH + 13% DAP 67.843 7.629 59.438 6.947 86% DMH + 13% DAP + 1% CA1025 73.781 15.805 82.893 7.693 85% DMH + 13% DAP + 2% CA1025 87.873 6.696 83.829 8.665 84% DMH + 13% DAP + 3% CA1025 88.965 13.690 85.755 14.067 83% DMH + 13% DAP + 4% CA1025 88.611 7.886 85.308 8.783
Again, the effect on bond strength of the addition of CA1025 is clearly evidenced. [0079] DMH: dextrose monohydrate [0080] AmSO4: ammonium sulphate [0081] DAP: Diammonium phosphate [0082] CS: High molecular weight chitosan from Sigma Aldrich, CAS no 9012-76-4 (419419) [0083] CaMH: citric acid monohydrate [0084] CA1025: trade name of a commercially available azetidinium polymer

[0085] The experiments were repeated with binder compositions as shown in Table 7 below. Bond strength of weathered and unweathered veils impregnated with the relevant binder compositions and cured for 8 minutes at 200 C. were determined as disclosed above. The results averaged over 8 replicates are shown in Table 7 below.

TABLE-US-00007 TABLE 7 Bond Strength of Veils Bond Strength of Veils Unweathered after weather treatment Average Bond STDEV Average Bond STDEV Binder Formulations Strength (N) (+/) Strength (N) (+/) 85% DMH + 15% HMDA 72.843 7.760 59.972 10.264 80% DMH + 15% HMDA + 5% HPC 67.175 6.859 53.989 5.306 80% DMH + 15% HMDA + 5% NaCMC 93.310 7.224 77.060 6.285 80% DMH + 15% HMDA + 5% CA1025 85.703 9.744 88.180 7.190 75% DMH + 15% HMDA + 10% CA1025 85.419 12.881 93.776 7.381 [0086] DMH: dextrose monohydrate [0087] HMDA: hexamethylene diamine [0088] HPC: hydroxypropyl cellulose [0089] CA1025: trade name of a commercially available azetidinium polymer
Clearly, bond strength of weathered and unweathered veils is essentially maintained or even increased despite reduced dextrose available for reaction with HMDA cross-linker.
Accorder to further aspects, the present invention provides an aqueous curable binder composition, an assembly of fibers or particles and a process as set out in the following aspects: [0090] Aspect 1. An aqueous curable binder composition comprising starting materials required for forming a thermoset resin upon curing and a matrix polymer. [0091] Aspect 2. The aqueous curable binder composition of aspect 1 comprising a polyhydroxy component, a polycarboxylic acid component, or an anhydride, ester or salt derivative thereof for forming a thermoset resin upon curing, and a matrix polymer. [0092] Aspect 3. The aqueous curable binder composition of aspect 2 wherein the polycarboxylic acid component is selected from monomeric and polymeric polycarboxylic acids.

[0093] Aspect 4. The aqueous curable binder composition of aspect 4 wherein the polycarboxylic acid component is a monomeric polycarboxylic acid, such as dicarboxylic acid, including, but not limited to, unsaturated aliphatic dicarboxylic acids, saturated aliphatic dicarboxylic acids, aromatic dicarboxylic acids, unsaturated cyclic dicarboxylic acids, saturated cyclic dicarboxylic acids, hydroxy-substituted derivatives thereof, or, tricarboxylic acid, including, but not limited to, unsaturated aliphatic tricarboxylic acids, saturated aliphatic tricarboxylic acids, aromatic tricarboxylic acids, unsaturated cyclic tricarboxylic acids, saturated cyclic tricarboxylic acids, hydroxy-substituted derivatives thereof, preferably citric acid, and mixtures thereof. [0094] Aspect 5. The aqueous curable binder composition of aspect 2 wherein the salt derivative of the polycarboxylic acid component is an ammonium salt. [0095] Aspect 6. The aqueous curable binder composition of any of the preceding aspects wherein the polyhydroxy component is a carbohydrate component selected from monosaccharide in its aldose or ketose form, including a triose, a tetrose, a pentose, a hexose, or a heptose; or a polysaccharide or an oligosaccharide; or a component that yields one or more reducing sugars in situ, or combinations thereof. [0096] Aspect 7. The aqueous curable binder composition of aspect 1 comprising a carbohydrate component and a nitrogen containing component for forming a thermoset resin upon curing, and a matrix polymer. [0097] Aspect 8. The aqueous curable binder composition of aspect 7 wherein the carbohydrate component is selected from monosaccharide in its aldose or ketose form, including a triose, a tetrose, a pentose, a hexose, or a heptose; or an oligosaccharide or a polysaccharide; or a component that yields one or more reducing sugars in situ, or combinations thereof.

[0098] Aspect 9. The aqueous curable binder composition of any of aspects 7 or 8 wherein the nitrogen containing component is an ammonium salt of an inorganic acid, selected from phosphoric, sulphuric, nitric and carbonic acid, preferably ammonium sulphate or ammonium phosphate.

[0099] Aspect 10. The aqueous curable binder composition of any of aspects 7 or 8 wherein the nitrogen containing component is selected from polyamine functional compounds comprising primary and/or secondary and/or tertialy and/or quaternary amine functional groups.

[0100] Aspect 11. The aqueous curable binder composition of any of aspect 10 wherein the polyamine functional compound has the formula of H.sub.2N-Q-NH.sub.2, wherein Q is an alkyl, cycloalkyl, heteroalkyl, or cycloheteroalkyl, each of which optionally substituted.

[0101] Aspect 12. The aqueous curable binder composition of aspect 11 wherein the polyamine functional compound is selected from di-amine, tri-amine, tetra-amine, and penta-amine, more specifically 1,6-diaminohexane and 1,5-diamino-2-methylpentane, diethylenetriamine, 1-piperazine-ethaneamine, and bis(hexamethylene)triamine, triethylenetetramine, tetraethylenepentamine, polyethyleneimine (PEI), polyninyl amine, polyether amine, polylysine.

[0102] Aspect 13. The aqueous curable binder composition of any of the preceding aspects wherein the matrix polymer is selected from naturally derived polymers, such as polysaccharides, such as cellulose, starch, alginate, hyaluronic acid, and their derivatives, carboxymethyl cellulose (CMC), hydroxypropyl cellulose (HPC), 2-hydroxyethyl cellulose (HEC), synthetically derived polymers, such as polyvinyls (PVA, PVAc, PAN), polyacrylics, polyacrylate, polymethacrylate, polyacrylamide, polymethacrylamides, polyurethanes, polyesters, aliphatic isocyanate oligomers, polyazetidinium, copolymers thereof and mixtures thereof.

[0103] Aspect 14. The aqueous curable binder composition of aspect 13 wherein the matrix polymer is selected from cellulose derivatives, such as carboxymethyl cellulose (CMC), hydroxypropyl cellulose (HPC), 2-hydroxyethyl cellulose (HEC); polyvinyl acetate (PVAc), aliphatic isocyanate oligomers, or mixtures thereof.

[0104] Aspect 15. The aqueous curable binder composition of any of the preceding aspects wherein the matrix polymer shows a molecular weight ranging from 500 Daltons (Da) to 210.sup.6 Da, preferably from 110.sup.3-510.sup.5 Da, more preferably from 510.sup.4Da-310.sup.5 Da. [0105] Aspect 16. The aqueous curable binder composition of any of aspects 7-15 wherein the dry weight ratio of carbohydrate to ammonium salt of inorganic or polycarboxylic acid or polyamine functional compound ranges from about 2 to about 35, preferably from about 2.5 to about 13.

[0106] Aspect 17. The aqueous curable binder composition of aspect 16 wherein the matrix polymer makes up from about 1 to 20% of the dry weight of the binder composition, preferably from about 2 to 18% dry weight, more preferably from 5 to 15% dry weight of the composition.

[0107] Aspect 18. The aqueous curable binder composition of any of the preceding aspects further comprising dyes, antifungal agents, antibacterial agents, hydrophobes, silicone containing coupling agents and/or other additives known in the art for such binder compositions.

[0108] Aspect 19. The aqueous binder composition of any of the preceding aspects wherein a component is selected micro-/or nano-particles derived from natural or synthetic polymers of their combination such as nanocelluloses, or from inorganic materials such as MgO, CaO, Al.sub.2O.sub.3 and CaCO.sub.4, or nanoclays such as montmorillonite, bentonite, kaolinite, hectorite, and halloysite and other organically-modified nanoclays, and/or mixtures thereof.

[0109] Aspect 20. An assembly of fibers or particles bonded with an aqueous curable binder composition according to any of the preceding aspects or with a binder resulting from the curing of any of the curable binder compositions of the preceding aspects.

[0110] Aspect 21. The assembly of fibers according to aspect 20 being an insulation product, such as a mineral wool mat or other.

[0111] Aspect 22. The assembly of particles according to aspect 20 being a composite wood board, such as wood fiber board, wood particle board, plywood or similar board.

[0112] Aspect 23. A process for the manufacturing of an assembly of fibers or particles according to any of aspects 20-22 characterized in that it comprises the successive or concomitant application of the relevant components of the aqueous curable binder composition of any of aspects 1-19, or the application of an aqueous binder composition according to any of aspects 1 to 19 onto a collection of fibers or particles; the gathering of the coated fibers or particles in an assembly; and curing, whereby the components of the aqueous curable binder composition are caused to react to form a macromolecular binder, and evaporating water.

[0113] Aspect 24. The process according to aspect 23 characterized in that curing is performed at a temperature ranging from 120 C.-200 C., preferably higher than 140 C., more preferably lower than 190 C., typically between 160 and 180 C.

[0114] Aspect 25. The process according to any of aspects 23-24 characterized in that the aqueous binder composition is applied by spraying onto the collection of fibers or particles.

[0115] Aspect 26. The process of any of aspects 23 to 25 wherein the assembly is a wood fiber board or wood particle board or similar wood board, subjected to pressing during curing.