Method for coating textile materials

Abstract

A method for coating a textile material, said method includes the following steps: a) incorporating activated carbon in powder form into a coating composition including an aqueous solvent and at least one organosilicon precursor, wherein the organosilicon precursor represents from 5 to 50% by volume relative to the whole of the aqueous solvent and organosilicon precursor, b) impregnating the textile material with the coating composition by padding and c) drying the impregnated textile material, characterised in that the coating composition contains no polycarboxylic acid or catalyst.

Claims

1. A process for coating a textile material, said process comprising the following steps: a) incorporating active charcoal in powder form into a coating composition comprising an aqueous solvent and at least one organosilicon precursor, in which the organosilicon precursor represents 5% to 50% by volume relative to the combination of aqueous solvent and organosilicon precursor, b) impregnating the textile material by padding with the coating composition, and c) drying the impregnated textile material, optionally, before step b), applying a precoating composition, on the textile material, comprising an organic solvent and a zirconium alkoxide, said precoating composition being free of polycarboxylic acid, wherein the organosilicon precursor of the coating composition and the zirconium alkoxide of the optionally applied precoating solution are sole sources of metal impregnating and coating the coated textile, wherein the coating composition is free of polycarboxylic acid and of catalyst, and wherein the coated textile has improved polar and non-polar toxic gas barrier properties compared to the non-coated textile.

2. The process as claimed in claim 1, wherein the coating composition is also free of surfactant.

3. The process as claimed in claim 1, wherein the textile material is a fabric, a nonwoven or a knit.

4. The process as claimed in claim 1, wherein the textile material comprises fibers including hydrolyzable functions.

5. The process as claimed in claim 1, wherein the aqueous solvent is water or a mixture of water and of an organic solvent.

6. The process as claimed in clam 1, wherein the organosilicon precursor is chosen from tetramethoxysilane (TMOS), tetraethoxysilane (TEOS), methyltrimethoxy silane (MTM), methyltriethoxysilane (MTE), phenyltrimethoxysilane (PhTMOS), phenyltriethoxysilane (PhTEOS), a fluoroalkyltrimethoxysilane, a fluoroalkyltriethoxy silane, a chloroalkylmethoxysilane, a chloroalkylethoxysilane, an aminopropyltriethoxysilane, (3-glycidyloxypropyl)trimethoxysilane (GPTMOS) and mixtures thereof.

7. The process as claimed in claim 6, wherein the silicon precursor is tetramethoxysilane (TMOS).

8. The process as claimed in claim 6, wherein the organosilicon precursor is a mixture of tetramethoxysilane (TMOS) with one or more precursors chosen from methyl trimethoxysilane (MTM), methyl triethoxysilane (MTE), phenyltrimethoxysilane (PhTMOS), phenyl triethoxysilane (PhTEOS), fluoroalkyltrimethoxysilane, a fluoroalkyltriethoxysilane, a chloroalkyimethoxysilane, a chloroalkylethoxysilane, an aminopropyltriethoxysilane, (3-glycidyloxypropyl)trimethoxysilane (GPTMOS), and mixtures thereof.

9. The process as claimed in claim 8, wherein the organosilicon precursor is a mixture of tetramethoxysilane (TMOS) with aminopropyl triethoxysilane (APTES).

10. The process as claimed in claim 1, wherein it includes from 1 to 3 successive cycles of impregnation by padding.

11. The process as claimed in claim 1, wherein the process further comprises, before step b), a step of applying the precoating composition, on the textile material, comprising the organic solvent and the zirconium alkoxide, said precoating composition being free of polycarboxylic acid.

12. The process as claimed it claim 1, wherein the textile material is a fabric or a nonwoven.

13. The process as claimed in claim 1, wherein the organosilicon precursor is chosen from tetramethoxysilane (TMOS), methyltrimethoxysilane (MTM), phenyltrimethoxysilane (PhTMOS), a fluoroalkyltrimethoxysilane, a chloroalkylmethoxysilane, an aminopropyltriethoxysilane, (3-glycidyloxypropyl)trimethoxysilane (GPTMOS), and mixtures thereof.

14. The process as claimed in claim 1, wherein the textile material comprises fibers including hydroxyl functions.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1: SEM images of cloth A before impregnation.

(2) FIG. 2: SEM images of cloth B before impregnation.

(3) FIG. 3: SEM images of cloth C before impregnation.

(4) FIG. 4: SEM images of cloth A with impregnation of a sol-gel solution containing 40 g/l of active charcoal (D.sub.1).

(5) FIG. 5: SEM images of cloth A with impregnation of a sol-gel solution containing 100 g/l of active charcoal (D.sub.2).

(6) FIG. 6: SEM images of cloth A with impregnation of a sol-gel solution containing 100 g/l of active charcoal (D′.sub.1).

(7) FIG. 7: SEM images of cloth A with impregnation of a sol-gel solution containing 100 g/l of active charcoal (D′.sub.2).

(8) FIG. 8: SEM images of cloth B with impregnation of a sol-gel solution containing 100 g/l of active charcoal (D.sub.2).

(9) FIG. 9: SEM images of cloth C with impregnation of a sol-gel solution containing 100 g/l of active charcoal (D.sub.2).

(10) FIG. 10: Photographs of cloth A: (A) before impregnation, (B) front side after impregnation with formula A.sub.1, (C) reverse side after impregnation with formula A.sub.1.

(11) FIG. 11: Photographs of cloth A: (A) before impregnation, (B) front side after impregnation with formula A.sub.2, (C) reverse side after impregnation with formula A.sub.2.

(12) FIG. 12: Photographs of cloth B: (A) before impregnation, (B) front side after impregnation with formula D.sub.2, (C) reverse side after impregnation with formula D.sub.2.

(13) FIG. 13: Photographs of cloth C: (A) before impregnation, (B) front side after impregnation with formula D.sub.2, (C) reverse side after impregnation with formula D.sub.2.

(14) FIG. 14: (A) Schematic view of the components of the tool for measuring the drape of the fabric; (B) schematic diagram for the measurement of the drape of the fabric.

(15) FIG. 15: (A) Photograph of the initial fabric in the tool for measuring the drape of the fabric; (B) photograph of the fabric impregnated with formula D.sub.2′.

(16) FIG. 16: Comparison of the normalized curves of methyl salicylate piercing with a deposition of 20 g/m.sup.2 onto cloth A with formulae D.sub.2 (strategy I) and D.sub.2′ (strategy II).

(17) FIG. 17: Comparison of the normalized curves of toluene piercing with a deposition of 20 g/m.sup.2 onto cloth A with formulae D.sub.2 (strategy I), D.sub.2′ (strategy II), E.sub.2 (strategy I) and E.sub.2′ (strategy II).

DETAILED DESCRIPTION

(18) Chemical Products Used Tetramethoxysilane (CAS No.: 681-84-5) (TMOS, Acros Organics, 99%); Methyltrimethoxysilane (CAS No.: 1185-55-3) (MTM, Sigma-Aldrich, 98%); 1H,1H,2H,2H-Perfluoroheptadecyltriethoxysilane (CAS No.: 101947-16-4) (17FTMOS, Sigma-Aldrich, 97%); Aminopropyltriethoxysilane (CAS No.: 919-30-2) (APTES, Acros Organics, 99%); Phenyltrimethoxysilane (CAS No.: 2996-92-1) (PhTMOS, TCI, >98%); Ethanol (CAS No.: 64-17-5) (Merck, Uvasol for spectroscopy); Acetonitrile (CAS No.: 75-05-8) (Merck, Lichrosolv gradient grade for liquid chromatography); Succinic acid (CAS No.: 110-15-6) (Sigma-Aldrich, Reagent Plus ≥99.0%); Sodium hypophosphite (CAS No.: 123333-67-5) (Sigma-Aldrich, hydrate).

Example 1: Preparation of Coated Fabrics

(19) The formulations according to strategies I, II and III described below were deposited on 5 cm×10 cm to 21 cm×30 cm pieces of cloth: cloth A (50/50 Kermel®/Lenzing FR® fabric (Kermel, Colmar, France) (Lenzing AG, Lenzing, Austria)), cloth B (50/50 Conex®/Lenzing FRO fabric (Teijin Aramid B.V., Arnhem, Netherlands) (Lenzing AG, Lenzing, Austria)) and cloth C (Nomex® felt (Dupont, Wilmington, Del., United States)) by full-bath impregnation and squeezing (padding principle) and the fabrics were then oven-dried for 2 minutes at 120° C. and left to stand for 24 hours at room temperature and atmospheric pressure in the laboratory. The initial amount deposited ranges between 10 and 435 g/m.sup.2. The mass per unit area of the sol-gel material is deduced by weighing the fabric before and after impregnation.

(20) I. Preparation of Coated Fabrics According to the Attachment Strategy Described in FR 2984343 A1 (with Polycarboxylic Acid)

(21) Formulation A.sub.1

(22) 0.131 g of succinic acid and 0.140 g of sodium hypophosphite are mixed in 17.73 mL of ultra-pure water in a hermetically sealed glass flask. The mixture is stirred on setting 4 of an IKA WERKE RO10 power multiple-stirrer plate (about 500 rpm) and at room temperature (20-22° C.) until the polyacid and the catalyst have dissolved. 0.805 g of active charcoal and 2.300 mL of TMOS are then added to the initial mixture.

(23) Dynamic viscosity: 3.5 cP (mPa.Math.s)

(24) The deposition of this formula onto textile indicates a mass per unit area of 29 g/m.sup.2.

(25) Formulation A.sub.2

(26) 0.200 g of succinic acid and 0.212 g of sodium hypophosphite are mixed in 27.03 mL of ultra-pure water in a hermetically sealed glass flask. The flask is placed at about 45° C. in a water bath covered with an aluminum foil, on a TECHLAB MAGNETIC STIRRER SH-4C heating stirrer (nominal temperature: 55° C.) and stirred at about 400-500 rpm until the polyacid and the catalyst have dissolved. 3.057 g of active charcoal and 3,600 mL of TMOS are then added to the initial mixture.

(27) Dynamic viscosity: 5.4 cP (mPa.Math.s)

(28) The deposition of this formula onto textile indicates a mass per unit area of 37 g/m.sup.2.

(29) Formulation B

(30) 0.333 g of succinic acid and 0.354 g of sodium hypophosphite are mixed in 45.06 mL of ultra-pure water in a hermetically sealed glass flask. The mixture is stirred on setting 4 of an IKA WERKE RO10 power multiple-stirrer plate (about 500 rpm) and at room temperature (20-22° C.) until the polyacid and the catalyst have dissolved. 2.033 g of active charcoal, 3.000 mL of TMOS and 2.780 mL of MTM are then added to the initial mixture.

(31) Dynamic viscosity: 2.0 cP (mPa.Math.s)

(32) The deposition of this formula onto textile indicates a mass per unit area of 22 g/m.sup.2.

(33) Formulation C.sub.1

(34) 0.267 g of succinic acid and 0.284 g of sodium hypophosphite are mixed in 18.02 mL of ultra-pure water and 18.02 mL of ethanol in a hermetically sealed glass flask. The mixture is stirred on setting 4 of the IKA WERKE RO10 power multiple-stirrer plate (about 500 rpm) and at room temperature (20-22° C.) until the polyacid and the catalyst have dissolved. 1.643 g of active charcoal, 4.800 mL of TMOS and 0.226 mL of APTES are then added to the initial mixture.

(35) Dynamic viscosity: 18.7 cP (mPa.Math.s)

(36) The deposition of this formula on textile indicates a mass per unit area of 27 g/m.sup.2.

(37) Formulation C.sub.2

(38) 0.268 g of succinic acid and 0.284 g of sodium hypophosphite are mixed in 18.02 mL of ultra-pure water and 18.02 mL of ethanol in a hermetically sealed glass flask. The mixture is stirred on setting 4 of the IKA WERKE RO10 power multiple-stirrer plate (about 500 rpm) and at room temperature (20-22° C.) until the polyacid and the catalyst have dissolved. 4.107 g of active charcoal, 4.800 mL of TMOS and 0.226 mL of APTES are then added to the initial mixture.

(39) Dynamic viscosity: 82.5 cP (mPa.Math.s)

(40) The deposition of this formula on textile indicates a mass per unit area of 36 g/m.sup.2.

(41) Formulation D.sub.1

(42) 0.237 g of succinic acid and 0.252 g of sodium hypophosphite are mixed in 15.98 mL of ultra-pure water and 15.98 mL of ethanol in a hermetically sealed glass flask. The mixture is stirred on setting 4 of the IKA WERKE RO10 power multiple-stirrer plate (about 500 rpm) and at room temperature (20-22° C.) until the polyacid and the catalyst have dissolved. 1.454 g of active charcoal, 4.000 mL of TMOS and 0.402 mL of APTES are then added to the initial mixture.

(43) Dynamic viscosity: 13.5 cP (mPa.Math.s)

(44) The deposition of this formula on textile indicates a mass per unit area of 27 g/m.sup.2.

(45) Formulation D.sub.2

(46) 0.296 g of succinic acid and 0.314 g of sodium hypophosphite are mixed in 19.97 mL of ultra-pure water and 19.97 mL of ethanol in a hermetically sealed glass flask. The mixture is stirred on setting 4 of the IKA WERKE RO10 power multiple-stirrer plate (about 500 rpm) and at room temperature (20-22° C.) until the polyacid and the catalyst have dissolved. 4.545 g of active charcoal, 5.000 mL of TMOS and 0.502 mL of APTES are then added to the initial mixture.

(47) Dynamic viscosity: 12.4 cP (mPa.Math.s)

(48) The deposition of this formula on textile indicates a mass per unit area of 42 g/m.sup.2.

(49) Formulation E.sub.1

(50) 0.127 g of succinic acid and 0.135 g of sodium hypophosphite are mixed in 8.57 mL of ultra-pure water in a hermetically sealed glass flask. The mixture is stirred on setting 4 of an IKA WERKE RO10 power multiple-stirrer plate (about 500 rpm) and at room temperature (20-22° C.) until the polyacid and the catalyst have dissolved, followed by addition of 0.773 g of active charcoal. 8.57 mL of ethanol, 0.337 mL of 17FTMOS, 2.100 mL of TMOS and 0.108 mL of APTES are mixed in a second hermetically sealed glass flask. The contents of the second flask are then poured into the first with continued stirring.

(51) Dynamic viscosity: 37.0 cP (mPa.Math.s)

(52) The deposition of this formula on textile indicates a mass per unit area of 30 g/m.sup.2.

(53) Formulation E.sub.2

(54) 0.127 g of succinic acid and 0.135 g of sodium hypophosphite are mixed in 8.57 mL of ultra-pure water in a hermetically sealed glass flask. The mixture is stirred on setting 4 of an IKA WERKE RO10 power multiple-stirrer plate (about 500 rpm) and at room temperature (20-22° C.) until the polyacid and the catalyst have dissolved, followed by addition of 1.937 g of active charcoal. 8.57 mL of ethanol, 0.337 mL of 17FTMOS, 2.100 mL of TMOS and 0.108 mL of APTES are mixed in a second hermetically sealed glass flask. The contents of the second flask are then poured into the first with continued stirring.

(55) Dynamic viscosity: 50.0 cP (mPa.Math.s)

(56) The deposition of this formula on textile indicates a mass per unit area of 44 g/m.sup.2.

(57) Formulation F.sub.1

(58) 0.138 g of succinic acid and 0.147 g of sodium hypophosphite are mixed in 9.28 mL of ultra-pure water in a hermetically sealed glass flask. The mixture is stirred on setting 4 of an IKA WERKE RO10 power multiple-stirrer plate (about 500 rpm) and at room temperature (20-22° C.) until the polyacid and the catalyst have dissolved, followed by addition of 0.840 g of active charcoal. 9.28 mL of ethanol, 0.365 mL of 17FTMOS, 2.200 mL of TMOS and 0.233 mL of APTES are mixed in a second hermetically sealed glass flask. The contents of the second flask are then poured into the first flask and stirring of the mixture is continued.

(59) Dynamic viscosity: 20.0 cP (mPa.Math.s)

(60) The deposition of this formula on textile indicates a mass per unit area of 31 g/m.sup.2.

(61) Formulation F.sub.2

(62) 0.138 g of succinic acid and 0.146 g of sodium hypophosphite are mixed in 9.28 mL of ultra-pure water in a hermetically sealed glass flask. The mixture is stirred on setting 4 of an IKA WERKE RO10 power multiple-stirrer plate (about 500 rpm) and at room temperature (20-22° C.) until the polyacid and the catalyst have dissolved, followed by addition of 2.104 g of active charcoal. 9.28 mL of ethanol, 0.365 mL, of 17FTMOS, 2.200 mL of TMOS and 0.233 mL of APTES are mixed in a second hermetically sealed glass flask. The contents of the second flask are then poured into the first flask and stirring of the mixture is continued.

(63) Dynamic viscosity: 20.0 cP (mPa.Math.s)

(64) The deposition of this formula on textile indicates a mass per unit area of 40 g/m.sup.2.

(65) II. Preparation of Coated Fabrics According to an Attachment Strategy without Polycarboxylic Acid in One Step

(66) Formulation A.sub.1′

(67) 2.381 g of active charcoal and then 7.000 mL of TMOS are added to a volume of 52.56 mL of ultra-pure water in a hermetically sealed glass flask. The mixture is stirred at room temperature (20-22° C.) on setting 4 of the IKA WERKE RO10 power multiple-stirrer plate (about 500 rpm).

(68) Dynamic viscosity: 3.1 cP (mPa.Math.s)

(69) The deposition of this formula on textile indicates a mass per unit area of 21 g/m.sup.2.

(70) Formulation A.sub.2′

(71) 5.956 g of active charcoal and then 7.000 mL of TMOS are added to a volume of 52.56 mL of ultra-pure water in a hermetically sealed glass flask. The mixture is stirred at room temperature (20-22° C.) on setting 4 of the IKA WERKE RO10 power multiple-stirrer plate (about 500 rpm).

(72) Dynamic viscosity: 7.3 cP (mPa.Math.s)

(73) The deposition of this formula on textile indicates a mass per unit area of 36 g/m.sup.2.

(74) Formulation D.sub.1′

(75) 1.816 g of active charcoal are mixed with a volume of 19.97 mL of ultra-pure water in a hermetically sealed glass flask. 19.97 mL of ethanol, 5.000 mL of TMOS and 0.502 mL of APTES are mixed in a second hermetically sealed glass flask. The contents of the second flask are then poured into the first flask and the mixture is stirred at room temperature (20-22° C.) on setting 4 of the IKA WERKE RO10 power multiple-stirrer plate (about 500 rpm).

(76) The deposition of this formula on textile indicates a mass per unit area of 28 g/m.sup.2.

(77) Formulation D.sub.2′

(78) 4.541 g of active charcoal are mixed with a volume of 19.97 mL of ultra-pure water in a hermetically sealed glass flask. 19.97 mL of ethanol, 5.000 mL of TMOS and 0.502 mL of APTES are mixed in a second hermetically sealed glass flask. The contents of the second flask are then poured into the first flask and the mixture is stirred at room temperature (20-22° C.) on setting 4 of the IKA WERKE RO10 power multiple-stirrer plate (about 500 rpm).

(79) Dynamic viscosity: 10-12 cP (mPa.Math.s)

(80) The deposition of this formula on textile indicates a mass per unit area of 33 g/m.sup.2.

(81) Formulation E.sub.1′

(82) 1.129 g of active charcoal are mixed with a volume of 12.24 mL of ultra-pure water in a hermetically sealed glass flask. 12.24 mL of ethanol, 0.482 mL of 17FTMOS, 3.000 mL of TMOS and 0.154 mL of APTES are mixed in a second hermetically sealed glass flask. The contents of the second flask are then poured into the first flask and the mixture is stirred at room temperature (20-22° C.) on setting 4 of the IKA WERKE RO10 power multiple-stirrer plate (about 500 rpm).

(83) The deposition of this formula on textile indicates a mass per unit area of 17 g/m.sup.2.

(84) Formulation E.sub.2′

(85) 2.813 g of active charcoal are mixed with a volume of 12.24 mL of ultra-pure water in a hermetically sealed glass flask. 12.24 mL of ethanol, 0.482 mL of 17FTMOS, 3.000 mL of TMOS and 0.154 mL of APTES are mixed in a second hermetically sealed glass flask. The contents of the second flask are then poured into the first flask and the mixture is stirred at room temperature (20-22° C.) on setting 4 of the IKA WERKE RO10 power multiple-stirrer plate (about 500 rpm).

(86) The deposition of this formula on textile indicates a mass per unit area of 35 g/m.sup.2.

(87) Formulation G.sub.1′

(88) 0.200 g of active charcoal are mixed with a volume of 17.52 mL of ultra-pure water in a hermetically sealed glass flask. 2.100 mL of TMOS and 0.293 mL of PhTMOS are then added and the mixture is stirred at room temperature (20-22° C.) on setting 4 of the IKA WERKE RO10 power multiple-stirrer plate (about 500 rpm).

(89) Dynamic viscosity: 1.9 cP (mPa.Math.s)

(90) The deposition of this formula on textile indicates a mass per unit area of 18 g/m.sup.2.

(91) Formulation G.sub.2′

(92) 0.397 g of active charcoal are mixed with a volume of 17.52 mL of ultra-pure water in a hermetically sealed glass flask. 2.100 mL of TMOS and 0.293 mL of PhTMOS are then added and the mixture is stirred at room temperature (20-22° C.) on setting 4 of the IKA WERKE RO10 power multiple-stirrer plate (about 500 rpm).

(93) Dynamic viscosity: 2.8 cP (mPa.Math.s)

(94) The deposition of this formula on textile indicates a mass per unit area of 19 g/m.sup.2.

(95) Formulation H.sub.1′

(96) 0.411 g of active charcoal are mixed with a volume of 18.02 mL of ultra-pure water in a hermetically sealed glass flask. 1.800 mL of TMOS and 0.753 mL of PhTMOS are then added and the mixture is stirred at room temperature (20-22° C.) on setting 4 of the IKA WERKE RO10 power multiple-stirrer plate (about 500 rpm).

(97) Dynamic viscosity: 2.2 cP (mPa.Math.s)

(98) The deposition of this formula on textile indicates a mass per unit area of 20 g/m.sup.2.

(99) Formulation H.sub.2′

(100) 0.823 g of active charcoal are mixed with a volume of 18.02 mL of ultra-pure water in a hermetically sealed glass flask. 1.800 mL of TMOS and 0.753 mL of PhTMOS are then added and the mixture is stirred at room temperature (20-22° C.) on setting 4 of the IKA WERKE RO10 power multiple-stirrer plate (about 500 rpm).

(101) Dynamic viscosity: 13.0 cP (mPa.Math.s)

(102) The deposition of this formula on textile indicates a mass per unit area of 26 g/m.sup.2.

(103) Tables 1 and 2 below summarize the masses per unit area obtained for the various formulations. It is recalled that: the attachment strategy I according to FR 2984343 A1 is performed with the addition of succinic acid and sodium hypophosphite; the one-step attachment strategy II is direct attachment with the silicon-based precursors used.

(104) TABLE-US-00001 TABLE 1 Strategy I Sol-gel Sol-gel deposition Concentration of reaction with active active charcoal time before charcoal (g/m.sup.2) on Sol-gel precursors Formulae (g/l) deposition cloth A (averages) TMOS A.sub.1 40.2 65 h 29 TMOS A.sub.2 99.8 24 h 37 TMOS/MTM B 40.0  6 days 22 TMOS/APTES C.sub.1 40.0  6 h 27 TMOS/APTES C.sub.2 100.0 25 h 36 TMOS/APTES D.sub.1 40.0  2 h 27 TMOS/APTES D.sub.2 100.0  2 h 42  1 h 45  37 (cloth B)  1 h 45 435 (cloth C) TMOS/APTES/17FTMOS E.sub.1 40.0  5 h 30 TMOS/APTES/17FTMOS E.sub.2 100.1 16 h 30 44 TMOS/APTES/17FTMOS F.sub.1 40.0  1 h 31 TMOS/APTES/17FTMOS F.sub.2 100.2  2 h 20 40

(105) TABLE-US-00002 TABLE 2 Strategy II Sol-gel Sol-gel deposition Concentration of reaction with active charcoal active charcoal time before (g/m.sup.2) on cloth A Sol-gel precursors Formulae (g/l) deposition (averages) TMOS A.sub.1′ 40.0 14 days 21 TMOS A.sub.2′ 100.0 28 days 36 TMOS/APTES D.sub.1′ 40.0  1 min 28 TMOS/APTES D.sub.2′ 100.0 35 min 33 TMOS/APTES/17FTMOS E.sub.1′ 40.1  5 min 17 TMOS/APTES/17FTMOS E.sub.2′ 100.0 10 days 35 TMOS/PhTMOS G.sub.1′ 10.0  3 days 18 TMOS/PhTMOS G.sub.2′ 20.0 10 days 19 TMOS/PhTMOS H.sub.1′ 20.0  3 days 20 TMOS/PhTMOS H.sub.2′ 40.0 21 days 26

Example 2: Properties of the Impregnated Fabrics of Example 1

(106) Scanning Electron Microscopy

(107) In order to demonstrate the fact that the active charcoal is bonded to the textile by means of the presence of the sol-gel, the textiles were characterized by SEM before and after impregnation with the solutions.

(108) Scanning Electron Microscopy (SEM) is a powerful technique for observation of the topography of surfaces. It is based mainly on the detection of secondary electrons emerging from the surface under the impact of a very fine beam of primary electrons which scans the observed surface and makes it possible to obtain images with a separating power often less than 5 nm and a great depth of field. The instrument makes it possible to form a almost parallel, very fine (down to a few nanometers) beam of electrons that are strongly accelerated by voltages adjustable from 0.1 to 30 keV, to focus it on the zone to be examined and to scan it progressively. Suitable detectors make it possible to collect significant signals during the scanning of the surface and to form various significant images therefrom. The images of the samples of the fabrics were produced with the “Ultra 55” SEM machine from Zeiss. The samples are observed directly without particular deposition (metal, carbon). A low acceleration voltage of 3 keV and the InLens detector (back-scattered and secondary electron detector) allow observation of the samples and avoid a phenomenon of excessive charge due to the nature of the fabrics.

(109) The three cloths A, B and C (cloth A: 50/50 Kermel®/Lenzing fabric; cloth B: 50/50 Conex®/Lenzing fabric; cloth C: Nomex® felt) were observed before impregnation, without performing any particular preparation. The SEM images show that these three textiles have relatively smooth fibers (FIGS. 1 to 3), with a few roughnesses/grooves in the case of the two fabrics (FIGS. 2 and 3).

(110) The samples of cloth A impregnated with formulations D.sub.1, D.sub.2, D.sub.1′ and D.sub.2′ (example 1) were also observed by SEM. For formulations D.sub.1 and D.sub.2 prepared according to strategy I, the SEM images show that the sol-gel coats the active charcoal particles and binds them to the fibers forming a continuous cladding (FIGS. 4 and 5). The SEM images of the fabrics impregnated with formulations D.sub.1′ and D.sub.2′ prepared according to strategy II (FIGS. 6 and 7) show that the deposits are similar to those obtained with the solutions of strategy I. For the fabric impregnated with formulation D.sub.1′, it is in fact observed that the sol-gel, which is thicker and fractured, coats the active charcoal particles and binds them to the fibers, forming a cladding.

(111) The SEM images of the samples of cloths B and C impregnated with formulation D.sub.2 (example 1) also show that the sol-gel coats the active charcoal particles and binds them to the fibers, forming a continuous cladding (FIGS. 8 and 9). The particles are spaced wider apart in the case of the felt, whereas lumps are visible in the case of the open fabric Conex®/Lenzing (cloth B).

(112) Permeability to Air

(113) For the purpose of the intended applications, notably in filtration, it is crucial for the textiles to be sufficiently permeable to air and/or to liquids. The permeability to air of the textiles was thus measured before and after deposition, according to the standard ISO 9237:1995 at 100 Pa. The results of the measurements are presented in table 3.

(114) TABLE-US-00003 TABLE 3 Permeability to air Deposition of at 100 Pa (l/m.sup.2 .Math. s) Formula sol-gel with active Before After Textiles deposited charcoal (g/m.sup.2) deposition deposition Cloth A D.sub.2 42 139 22 Cloth B D.sub.2 37 1032 122 Cloth C D.sub.2 435 745 182

(115) For cloths B and C, the permeability to air is lowered after deposition, but remains suitable. Moreover, the structure of the impregnated textile plays a predominant role on the permeability, since, for the same formula deposited, cloth C (felt) is eight times more permeable than cloth A (Kermel®/Lenzing cloth), with, however, a deposit that is ten times greater.

(116) Visual Appearance

(117) The deposition of sol-gel with active charcoal is uniform and modifies the appearance of the textiles, irrespective of their structure (FIGS. 10, 11, 12, 13). The sol-gel formula has no impact on the visual appearance of the textiles after deposition, unlike its active charcoal content: the higher the concentration, the more the color tends toward black.

(118) Suppleness

(119) The suppleness of the textiles before/after deposition is evaluated by a drape angle measurement.

(120) The suppleness of the textiles before/after impregnation was evaluated with the suppleness measurement tool shown in FIG. 14A. This tool 1 consists of two parts, a lower part 2 serving as a support for the fabric T and an upper part 3 which fits onto the lower part to block the fabric T. FIG. 14B shows the schematic diagram for the measurement. To take a measurement, 5 cm of fabric are positioned “in empty space”, i.e. to the exterior of the measurement tool, a profile photograph is taken, and the angle α formed between the fabric and the vertical on the profile photograph is then measured using a protractor to evaluate the drape of the fabric.

(121) This tool allows a comparison of the samples with a reference (fabric without sol-gel) as shown by the photographs represented in FIG. 15.

(122) Tables 3 and 4 below summarize the suppleness measurements before/after sol-gel deposition.

(123) TABLE-US-00004 TABLE 4 Strategy I Deposition of sol-gel Formula with active charcoal Mean angle measured Textiles deposited (g/m.sup.2) (°) Cloth A — — 18 A.sub.1 29 83 A.sub.2 37 81 B 22 82 C.sub.1 27 81 C.sub.2 36 81 D.sub.1 27 70 D.sub.2 42 72 E.sub.1 30 77 E.sub.2 44 78 F.sub.1 31 65 F.sub.2 40 70 Cloth B — — 11 D.sub.2 37 79 Cloth C — — 69 D.sub.2 435  90

(124) TABLE-US-00005 TABLE 5 Strategy II Deposition of sol-gel Formula with active charcoal Mean angle measured Textiles deposited (g/m.sup.2) (°) Cloth A — — 18 A.sub.1′ 21 70 A.sub.2′ 36 50 D.sub.1′ 28 67 D.sub.2′ 33 81 E.sub.1′ 17 69 E.sub.2′ 35 69 G.sub.1′ 18 74 G.sub.2′ 19 64 H.sub.1′ 20 69 H.sub.2′ 26 73

(125) As expected, the textiles are more rigid after deposition. These measurements also show that the suppleness of the textiles may vary with the sol-gel formulae (precursors) and their active charcoal concentration. Moreover, the textiles impregnated with the formulations according to strategy II are overall more supple than those impregnated with the formulations according to strategy I.

(126) Hydrophobicity

(127) The precursors used for the formation of the sol-gel may be chosen so as to provide water-repellency properties. Thus, formulations containing fluoro precursors (such as formulae E.sub.1, F.sub.1, F.sub.2 and E′.sub.1) make it possible to obtain hydrophobic fabrics. The hydrophobic properties of the fabrics impregnated with formulations E.sub.1, E.sub.2, F.sub.1, F.sub.2, E′.sub.1 and E′.sub.2 were determined by contact angle measurements with the OCA 15EC goniometer from DataPhysics and the software SCA20 in dynamic mode with the acquisition of 4 measurements per second for 1 minute in order to determine the stability of the water drop (10 μL) on the fabric. Table 7 below summarizes the mean contact angles on 2 or 3 measurements at t0.

(128) TABLE-US-00006 TABLE 6 Formula Textile deposited Hydrophobic Contact angle (°) Cloth A — No 0 E.sub.1 Yes 150 ± 5 E.sub.2 No 0 F.sub.1 Yes 165 ± 5 F.sub.2 Yes 140 ± 5 E.sub.1′ Yes 150 ± 5 E.sub.2′ No 0

Example 3: Gas-Phase Filtration

(129) The fabrics impregnated with each sol-gel formulation were exposed to gaseous mixtures containing methyl salicylate or toluene to test the trapping efficiency as a function of the porosity properties of the sol-gel materials and the intrapore polarity. The curves of piercing under gaseous streams were established for each pollutant.

(130) 3.1 Materials and Methods

(131) Permeability of the Fabrics to Gases

(132) In order to test the permeability of the fabrics to gases, a test bench was installed in the laboratory. For this, a “Porometer 3G, sample holder 37 mm” porometer from Quantachrome was used. This porometer allows the testing of a fabric 37 mm in diameter (cutting performed with a punch). The leaktightness is ensured by O-ring joints. Thus, the gas stream passes through all of the test fabric.

(133) The fabric test bench consists of two 4-way valves upstream and downstream of the sample holder, for measuring the gas streams on either side of the sample holder. The tests showed that there is no (or little) loss of pressure in the presence of the test fabric. The measurements of the pollutant contents are performed in the gas stream after the sample holder using a PID detector (Photo-Ionization Detector) in order to obtain the pollutant piercing curve. The permeability of the fabrics was tested using two pollutants: toluene and methyl salicylate. Each pollutant has an intrinsic mode of exposure. These modes are described below.

(134) Test of Permeability to Toluene:

(135) For the toluene exposure tests, this pollutant is obtained from a bottle calibrated at 100 ppm (the flow meter used is in the range: 0-100 mL/min) and then diluted in dry nitrogen (the flow meter used is in the range: 0-1 L/min). The diluted gas stream is placed in contact with the test fabric. An initial toluene content of 3-4 ppm is used for the permeability tests.

(136) Test of Permeability to Methyl Salicylate:

(137) For the methyl salicylate exposure tests, the vapors of this pollutant are generated by bubbling with dry nitrogen (the flow meter used is in the range: 0-1 L/min). The stream of gas enriched in methyl salicylate is placed in contact with the test fabric. A thermostat/cryostat to adjust the temperature of the bubbler containing the methyl salicylate (coil) is used so as to ensure the reproducibility of the exposure tests. The bubbler containing the methyl salicylate is thus regulated at 20° C. By using a flow of dry nitrogen of 300 mL/min, an initial content of 55-60 ppm of methyl salicylate is obtained.

(138) Methods for Exploiting the Methyl Salicylate Permeability Data

(139) The methyl salicylate permeability tests consist in measuring the salicylate content (in ppm) as a function of time. This plot is known as a piercing curve, the “S” shape of which is more or less pronounced. Comparison of the methyl salicylate piercing curves normalized with a deposit of 20 g/m.sup.2 for the initial fabric, formula D.sub.2 (strategy I) and formula D′.sub.2 (strategy II) is presented in FIG. 16.

(140) The piercing curves obtained were exploited by two methods: decomposition of the piercing curve and modeling of the piercing curve. The two methods are detailed below.

(141) Method 1: Decomposition of the Piercing Curve

(142) The first method for evaluating the filtration consists in decomposing the piercing curve and in analyzing the total trapping times. The total trapping times are determined for a methyl salicylate content at 0 ppm (t @ 0 ppm), a methyl salicylate content of less than 1 ppm (t<1 ppm), less than 5 ppm (t<5 ppm) and less than 20 ppm (t<20 ppm). These total trapping times constitute the characteristic times of the decomposition method.

(143) Method 2: Modeling of the Piercing Curve

(144) The second method for evaluating the filtration consists in modeling the piercing curve by a sigmoid function according to the Hill model described below. This model was selected since, by definition, it allows modeling starting from the point (0,0), i.e.: a salicylate content of 0 ppm at t=0 min. This model, derived from enzymatic catalysis, models strictly positive data following a sigmoid (“S”-shaped curve), which indeed corresponds to the piercing curves obtained by exposing the fabrics impregnated with sol-gel to methyl salicylate.

(145) The characteristic time of the piercing curve modeling method is thus: t.sub.1/2. Furthermore, from the parameters of the model, the slope of the curve may be calculated. For this, two points are necessary: A (t.sub.A; T.sub.A) and B (t.sub.B; T.sub.B). The calculation of the coordinates and of the slope are noted in the table below.

(146) Data Comparison: Normalization of the Characteristic Times

(147) The masses per unit area of the sol-gel deposits range between 15 and 30 g/m.sup.2. However, data comparison is only possible for an identical mass. Thus, to overcome the differences in masses per unit area, the characteristic times of the two methods described above were normalized to a mean deposit of 20 g/m.sup.2. In practice, the normalization is calculated as follows:

(148) $.Math.t\left(\min \right).Math.=\frac{t_{\mathrm{characteristic}}\left(\min \right)}{\mathrm{Experimental}\mathrm{mass}\mathrm{per}\mathrm{unit}\mathrm{area}\left(g\text{/}{m}^2\right)}\times \mathrm{Mass}\mathrm{per}\mathrm{unit}\mathrm{area}\mathrm{of}20g\text{/}{m}^2$

(149) In this manner, the data are reported for an identical weight: comparison of the formulae is thus possible.

(150) 3.2 Results

(151) Exposure to Methyl Salicylate

(152) The results of the attachment strategies I and II are reported in Tables 7 and 8 below for the methyl salicylate trapping efficiency.

(153) TABLE-US-00007 TABLE 7 Strategy I Time (min) Slope (ppm/ |t.sub.@ 0 ppm| |t.sub.<1 ppm| |t.sub.<5 ppm| |t.sub.<20 ppm| |t.sub.1/2| min) Cloth A 0.0 1.0 1.5 3.0 4.2 6.42 without deposit Formula A.sub.1 16.2 25.0 32.4 42.2 52.6 1.68 A.sub.2 6.92 19.0 27.7 38.5 58.1 1.47 B — 1.07 2.88 7.5 11.5 1.93 C.sub.1 — 11.3 17.4 23.4 31.6 3.32 C.sub.2 — 18.3 24.9 33.8 50.5 2.02 D.sub.1 — 11.2 17.9 25.4 36.5 2.61 D.sub.2 16.1 37.1 51.7 76.1 101.8 0.56 E.sub.1 7.12 14.4 19.6 27.8 33.5 2.25 E.sub.2 17.0 22.5 29.3 38.6 51.4 1.71 F.sub.1 13.6 19.1 21.2 36.9 40.9 1.17 F.sub.2 10.8 19.6 23.5 30.8 42.3 1.90 Cloth B 0.00 1.13 1.65 3.68 4.7 4.72 without deposit Formula D.sub.2 0.00 15.3 36.1 68.6 95.4 0.53 Cloth C 0.00 0.83 1.80 2.50 3.7 6.77 without deposit Formula D.sub.2 13.0 17.2 22.0 35.0 58.9 3.09

(154) TABLE-US-00008 TABLE 8 Strategy II Time (min) Slope |t.sub.@0 ppm| |t.sub.<1 ppm| |t.sub.<5 ppm| |t.sub.<20 ppm| |t.sub.1/2| (ppm/min) Cloth A 0.0 1.0 1.5 3.0 4.2 6.42 without deposit Formula D.sub.1′ 45.6 53.2 64.9 84.7 99.4 0.81 D.sub.2′ — 53.9 76.6 112 134.6 0.58 E.sub.1′ — 17.4 22.5 31.1 39.1 1.36 E.sub.2′ — 54.9 71.3 92.0 106.8 0.87 G.sub.1′ — 21.6 31.6 44.1 49.5 1.19

(155) The results obtained in the filtration of methyl salicylate show that the textiles are much more efficient after deposition. Moreover, all of the formulations tested according to attachment strategy II show better filtration performance than the formulations prepared according to attachment strategy I based on the same sol-gel precursors. These results clearly demonstrate that the incorporation of the polycarboxylic acid and of the catalyst modify the sol-gel, making it unsuitable for application in gas filtration. Similarly, the filtration performance qualities for the same formulation are better when the active charcoal concentration is higher.

(156) The best result in terms of methyl salicylate permeability is obtained with formulation D.sub.2′ according to strategy II. However, considering the results obtained with formulation G.sub.1′, it is expected that the same formulation containing ten times more active charcoal (100 g/1) would make it possible to obtain a better result.

(157) Moreover, successive deposits were tested to increase the mass per unit area of the filtering material. From 1 to 3 successive deposits of formula A1 were prepared. These led to masses per unit area of between 24 and 90 g/m.sup.2. The methyl salicylate trapping efficiency results are indicated in table 9 below.

(158) TABLE-US-00009 TABLE 9 Successive deposits with strategy I Mass per Deposit unit area t.sub.1/2 Slope Formula number (g/m.sup.2) (min) (ppm/min) Initial 0 0 4.2 6.4 fabric A1 1 24 98.6 1.2 3 90 180.8 0.8

(159) Exposure to Toluene

(160) As for methyl salicylate, the toluene permeability tests consist in measuring the toluene content (in ppm) as a function of time. This plot is known as a piercing curve, the “S” shape of which is more or less pronounced. Comparison of the toluene piercing curves normalized with a deposit of 20 g/m.sup.2 for the initial fabric, formula D.sub.2 (strategy I) and formula D′.sub.2 (strategy II) is presented in FIG. 16.

(161) The data exploitation methods are the same as for methyl salicylate. The attachment strategies I and II are compared in tables 10 and 11 below for the toluene trapping efficiency.

(162) TABLE-US-00010 TABLE 10 Strategy I Time (min) |t.sub.@ 0 ppm| |t.sub.<1 ppm| |t.sub.< 2 ppm| |t.sub.<3 ppm| Cloth A without 0.0 0.2 0.3 0.4 deposit Formula A.sub.1 17.5 44.1 78.3 161 A.sub.2 30.8 93.8 145 — B 0.14 0.27 4.65 55.8 C.sub.1 0.94 43.0 66.0 104 C.sub.2 21.1 76.7 111 163 D.sub.1 18.7 48.5 76.9 136 D.sub.2 35.3 104 160 — E.sub.1 4.85 19.4 33.0 64.1 E.sub.2 11.3 42.8 67.6 131 F.sub.1 4.21 21.4 37.5 74.4 F.sub.2 34.2 54.8 86.6 — Cloth C without 0.00 0.27 0.82 26.0 deposit Formula D.sub.2 52.0 73.9 — —

(163) TABLE-US-00011 TABLE 11 Strategy II Time (min) |t.sub.@ 0 ppm| |t.sub.<1 ppm| |t.sub.< 2 ppm| |t.sub.<3 ppm| Cloth A without deposit 0.0 0.2 0.3 0.4 Formula D.sub.1′ 35.6 79.4 112 174 D.sub.2′ — 111 161 237 E.sub.1′ — 29.3 46.8 74.7 E.sub.2′ — 110 150 206 G.sub.1′ — 29.6 53.0 87.9

(164) The results obtained in terms of the toluene permeability follow the same trends as those obtained in terms of the methyl salicylate permeability. Specifically, the toluene filtration performance is also greater with the attachment strategy II, and also with a higher concentration of active charcoal.

(165) The best toluene permeability results are obtained with formulation D′.sub.2, which also gave the best performance for methyl salicylate.

Example 4: Porosity of the Sol-Gel Materials with Active Charcoal

(166) The porosity of the sol-gel materials was determined from the establishment of nitrogen adsorption isotherms (specific surface area, pore volume, pore size distribution). The intrapore polarity is revealed by the capacity of the material to more efficiently trap methyl salicylate in comparison with toluene.

(167) 4.1 Materials and Methods

(168) Nitrogen adsorption consists of the physisorption of nitrogen on the surface of a solid: this is a reversible phenomenon (adsorption/desorption). Nitrogen adsorption a volumetric technique: a volume of gas of known temperature and pressure is sent onto the sample, which has been degassed beforehand and maintained at the temperature of liquid nitrogen. An adsorption isotherm corresponding to the volume of gas adsorbed as a function of the partial pressure of nitrogen is established. Interpretation of the adsorption isotherms is performed on the basis of various analytical models: Brunauer-Emmett-Teller (BET) model, which is a model of adsorption of a monomolecular layer of nitrogen molecules into the pores, and a model based on the density functional theory (DFT) which reproduces, with the aid of Monte Carlo methods, the adsorption isotherm for pores of given size. These analyses make it possible to obtain three pieces of information: the specific surface area for adsorption, the pore volume and the pore size distribution. The analyses were performed with the AUTOSORB-1 porosity analyzer from Quantachrome.

(169) 4.1 Results

(170) The table below summarizes the polarity and the porosity of the sol-gel materials with active charcoal in the form of monoliths, obtained by BET analysis with nitrogen adsorption (specific surface area for adsorption, pore volume, pore size distribution).

(171) TABLE-US-00012 TABLE 12 Micropore, mesopore and Specific surface Pore macropore size distribution area (m.sup.2/g) volume (%) Formula S.sub.BET S.sub.DFT (cm.sup.3/g) <20 Å 20-500 Å >500 Å Strategy I A.sub.2 880 ± 80 810 ± 70 0.52 ± 0.01 56.5 44.5 0.0 D.sub.1 710 ± 50 680 ± 50 0.60 ± 0.02 51.5 49.5 0.0 D.sub.2 940 ± 80 940 ± 80 0.80 ± 0.05 53.9 47.1 0.0 E.sub.2 710 ± 50 690 ± 60 0.58 ± 0.02 72.0 28.0 0.0 Strategy II D.sub.1′ 760 ± 60 740 ± 60  52.7 47.3 0.0 D.sub.2′ 940 ± 80 900 ± 80 0.85 ± 0.05 48.5 51.5 0.0 E.sub.2′ 910 ± 80 900 ± 80 0.74 ± 0.04 63.9 37.1 0.0

(172) These results demonstrate above all that the composite material described in the invention (sol-gel with active charcoal) does indeed have substantial porosity, the presence of the sol-gel thus not blocking the pores of the active charcoal. Furthermore, and as expected, a higher concentration of active charcoal in the same sol-gel formulation leads to a higher specific surface area for adsorption and a higher pore volume. Finally, the sol-gel formulations according to strategy II have greater porosity (specific surface area for adsorption and pore volume) than those according to strategy I. For applications in filtration, strategy II again appears to be the most suitable.