BINDER COMPOSITION BASED ON BIOSOURCED INGREDIENTS AND USE THEREOF FOR FORMING NON-WOVEN GLASS-FIBRE WEBS

Abstract

The invention relates to an aqueous binder composition containing, relative to the total dry weight of the binder composition, 10 to 40% by weight of a hydrogenated sugar, 25 to 55% by weight of citric acid, 25 to 50% by weight of a polysaccharide, and 1 to 10%, preferably 2 to 6%, by weight, of sodium hypophosphite or hypophosphorous acid. The polysaccharide is dissolved in the aqueous binder composition and chosen from functionalized starches and dextrins having a weight-average molar mass of between 150,000 and 2,000,000 and a solubility in water of between 50 and 85%. The invention also relates to a method for manufacturing non-woven webs based on mineral or organic fibers using such a composition and the non-woven webs thus obtained.

Claims

1. An aqueous binder composition, comprising; 10 to 40% by weight of a hydrogenated sugar, 25 to 55% by weight of citric acid, 25 to 50% by weight of a polysaccharide, which is dissolved in the aqueous binder composition, and is selected from the group consisting of a dextrin having a weight-average molar mass of between 150,000 and 2,000,000 and a solubility in water of between 50 and 85% and a functionalized starch, and 1 to 10% by weight of sodium hypophosphite or hypophosphorous acid, percentages being expressed relative to a total dry weight of the binder composition.

2. The aqueous binder composition according to claim 1, wherein the hydrogenated sugar, citric acidl and polysaccharide together represent at least 70 % of the dry weight of the binder composition.

3. The aqueous binder composition according to claim 1, wherein the hydrogenated sugar is selected from the group consisting of erythritol, arabitol, xylitol, sorbitol, mannitol, iditol, maltitol, isomaltitol, lactitol, cellobitol, palatinitol, maltotritoll and a hydrogenation of a starch hydrolysate or a lignocellulosic material

4. The aqueous binder composition according to claim 1, wherein the polysaccharide is a functionalized starch, which is selected from the group consisting of an etherified starch and an esterified starch.

5. The aqueous binder composition according to claim 1, wherein a weight ratio of the hydrogenated sugar to citric acid is between 0.2 and 1.0.

6. The aqueous binder composition according to claim 1, further comprising: relative to a total weight of the hydrogenated sugar, citric acid, and the polysaccharide, 4 to 20% of a polycarbodiimide.

7. The aqueous binder composition according to claim 1, further comprising: relative to a total weight of the hydrogenated sugar, citric acid, and the polysaccharide, 4 to 20% of a polyol having a molecular mass of less than 500 and having from 3 to 6 primary alcohol functions.

8. The aqueous binder composition according to claim 1, which has a solid content of between 5 and 20% by weight.

9. A method for manufacturing a non-woven web of mineral fibers and/or organic fibers, the method comprising: applying the aqueous binder composition according to claim 1 to a set of mineral and/or organic fibers gathered in the form of a non-woven web, and heating the non-woven web of mineral and/or organic fibers coated with the binder composition to a sufficient heating temperature and for a sufficient heating time to cross-link the binder composition and to form an insoluble and infusible cross-linked binder.

10. The method according to claim 9, wherein the heating temperature is between 180 C. and 230 C. and the heating time is between 10 seconds and 2 minutes.

11. A non-woven glass-fiber web, obtained by the method according to claim 9.

12. The non-woven glass-fiber web according to claim 11, which has a loss on ignition (LOI) of between 10 and 40% by weight.

13. The non-woven glass-fiber web according to claim 11, which has a mass per unit area of between 25 and 400 g/m.sup.2.

Description

EXAMPLES

[0080] Aqueous binder compositions are prepared comprising the ingredients indicated in Table 1 below.

Comparative Composition A (Absence of Polysaccharide)

[0081] Maltitol is dissolved in water, then citric acid and sodium hypophosphite (HPS) are added to the obtained solution. After complete dissolution of the ingredients, it is diluted to a dry matter content of 10%.

Comparative Composition B (Polysaccharide=Maltodextrin)

[0082] A maltodextrin having a dextrose equivalent (DE) of about 16.5 to 19.5 is dissolved in water, then maltitol, citric acid and HPS are added and the mixture is stirred at ambient temperature until all of the ingredients have dissolved. After complete dissolution of the ingredients, the dry matter content of the composition is adjusted to 10% by weight.

Composition 1 (According to the Invention)

[0083] A partially soluble dextrin having a weight-average molar mass of 200,000 Da, sold under the name Stabilys LAB 4511, is dissolved/dispersed in water at ambient temperature. Maltitol, citric acid and HPS are then added. After dissolution of these ingredients, the dry matter content of the composition is adjusted to 12% by weight.

Composition 2 (According to the Invention)

[0084] A partially soluble dextrin having a weight-average molar mass of 200 kDa, sold under the name Stabilys LAB 4511, is dissolved/dispersed in water at ambient temperature. Maltitol, citric acid and HPS and, as additional cross-linking agent, a polycarbodiimide (Permutex XR13-554 sold by the Stahl company) are added to the dextrin solution. The solids content is adjusted to 9% by weight.

Composition 3 (According to the Invention)

[0085] A partially soluble dextrin having a weight-average molar mass of 200 kDa, sold under the name Stabilys LAB 4511, is dissolved/dispersed in water at ambient temperature. Maltitol, citric acid, HPS and, as additional cross-linking agent, a beta-hydroxyalkylamide (Primid XL-552 sold by the EMS Chemie company) are added to the dextrin solution. The solids content is adjusted to 11% by weight.

Composition 4 (According to the Invention)

[0086] An acetylated starch (Tackidex G076 sold by the Roquette company) is dissolved in water by heating in an autoclave (130 C., 2 bar, dry extract of 21%), then, after cooling to ambient temperature, maltitol, citric acid and HPS are added. After dissolution of all the ingredients, the dry matter content of the composition is adjusted to 9% by weight.

[0087] The ingredients of the different comparative compositions and of the compositions according to the invention as well as their respective amounts are given in Table 1 below. The amounts are expressed as a % relative to the dry weight of the composition.

TABLE-US-00001 TABLE 1 Citric cross-linking Composition maltitol acid polysaccharide agent HPS A 31.8 63.5 4.7 B 21.9 43.8 29.6 (maltodextrin) 4.7 1 21.9 43.8 29.6 (Stabilys 4.7 LAB4511) 2 19.4 38.8 28.8 (Stabilys 8.8 4.7 LAB4511) 3 18.5 36.8 27.5 (Stabilys 13.2 4.0 LAB4511) 4 21.9 43.8 29.6 (Tackidex 4.7 G076)

[0088] Compositions A, B and 1-4 are used for manufacturing non-woven webs. For this purpose, each of the compositions of Table 1 is applied to a non-woven glass-fiber web having a weight per unit area of 35 g/m.sup.2 by immersing this web in the previous solutions.

[0089] After applying the binder composition, the impregnated web is heated for 60 seconds to a temperature of 210 C.

[0090] From the webs thus obtained, samples of 30 cm5 cm are cut out at the die in order to take measurements of tensile strength. The tensile strength in the dry state is determined by measuring the breaking force under uniaxial tension (100 mm/min, useful length of 20 cm) of the samples immediately after curing.

[0091] The tensile strength in the wet state is determined in the same way on samples that have remained for 10 minutes in water at 80 C.

[0092] Table 2 shows the tensile strengths in the dry and wet state for all the webs obtained. Each result is an average calculated from 12 samples, taken from a single web.

TABLE-US-00002 TABLE 2 Weight per Tensile strength Tensile strength unit area in the dry state in the wet state Composition polysaccharide LOI (%) (g/m.sup.2) (N/5 cm) (N/5 cm) A 22.7 0.7 35.0 73.4 13.1 24.3 6.6 B maltodextrin 27.1 1.5 37.2 108.5 16.1 29.1 8.1 1 Stabilys LAB4511 26.5 4.9 37.1 109.1 25.6 50.0 12.3 2 Stabilys + polycarbodiimide 22.6 0.9 34.4 100.6 9.5 60.9 7.5 3 Stabilys + hydroxyalkylamide 22.7 2.0 34.6 105.3 14.7 65.5 6.4 4 Tackidex 24.5 1.3 36.1 125.8 17.5 39.5 5.2

[0093] It is noted that the addition of a dextrin with high molecular weight that is partially soluble in water (Stabilys LAB4511) makes it possible to obtain webs having a tensile strength in the wet state that is twice as high.

[0094] The addition of a polycarbodiimide or a polyhydric alcohol (beta hydroxyalkylamide having four OH functions) further increases this tensile strength in the wet state.

[0095] Conversely, a maltodextrin with low molecular weight (composition B) does not provide a significant improvement in tensile strength.

[0096] The use of a functionalized starch (Tackidex G076) provides a less remarkable improvement than that of a dextrin with high molecular weight that is partially soluble in water at ambient temperature.