CONSOLIDATED NONWOVEN

Abstract

The present invention relates to a consolidated nonwoven consolidated by treatment with an aqueous binder composition comprising:

a polymer P,

a polyvinyl alcohol,

optional a starch compound S and

optional at least one metal compound M selected from the group consisting of magnesium, calcium and zinc, in the form of an oxide, hydroxide, carbonate or bicarbonate,

wherein the polymer P is obtainable by free radical aqueous emulsion polymerization of a monomer mixture of

75 to 99% by weight of one or more monomers a) selected from the group consisting of esters of acrylic and/or methacrylic acid with alkanols of 1 to 12 carbon atoms, aliphatic conjugated diene and aromatic vinyl compound

1 to 25% by weight of one or more monomers b) selected from the group consisting of N-methylolacrylamide, N-methylolmethacrylamide, glycidyl methacrylate and carboxylic acid-functional ethylenically unsaturated monomers

≥0 to 15% by weight of one or more further ethylenically unsaturated monomer c) different from any of monomers a) and b)

wherein the amounts of monomers a) to c) sum to 100 wt %,

the water-based binder composition, the process of for producing the consolidated nonwoven and its use as reinforcing insert for bituminized roofing membranes.

Claims

1-15. (canceled)

16. A consolidated nonwoven consolidated by treatment with an aqueous binder composition comprising: a polymer P, a polyvinylalcohol, optionally a starch compound S and optionally at least one metal compound M selected from the group consisting of magnesium, calcium and zinc, in the form of an oxide, hydroxide, carbonate or bicarbonate, wherein the polymer P is obtained by free radical aqueous emulsion polymerization of a monomer mixture of 75 to 99% by weight of one or more monomers a) selected from the group consisting of esters of one or more of acrylic and methacrylic acid with alkanols of 1 to 12 carbon atoms, aliphatic conjugated diene and aromatic vinyl compound, 1 to 25% by weight of one or more monomers b) selected from the group consisting of N-methylolacrylamide, N-methylolmethacrylamide, glycidyl methacrylate and carboxylic acid-functional ethylenically unsaturated monomers, and ≥0 to 15% by weight of one or more further ethylenically unsaturated monomer c) different from any of monomers a) and b), wherein the amounts of monomers a) to c) sum to 100 wt %.

17. The consolidated nonwoven according to claim 16, wherein the polymer P is obtained by free radical aqueous emulsion polymerization of a monomer mixture of 75 to 99% by weight of one or more monomers a) selected from the group consisting of esters of one or more of acrylic and methacrylic acid with alkanols of 1 to 12 carbon atoms, aliphatic conjugated diene and aromatic vinyl compound, 1 to 15% by weight of one or more of N-methylolacrylamide and N-methylol-methacrylamide (monomer b1), 0 to 5% by weight of one or more carboxylic acid-functional ethylenically unsaturated monomer b2), and 0 to 15% by weight of one or more further ethylenically unsaturated monomers c) different from any of monomers a), b1) and b2) wherein the amounts of monomers a) to c) sum to 100 wt %.

18. The consolidated nonwoven according to claim 16, wherein the Polymer P is obtained by free radical aqueous emulsion polymerization of a monomer mixture of 75 to 98% by weight of at least one monomer a) selected from the group consisting of styrene and ester of acrylic with alkanols of 1 to 4 carbon atoms, 1 to 10% by weight of one or more of N-methylol-acrylamide and N-methylol-methacrylamide (monomer b1), 1 to 5% by weight of one or more carboxylic acid-functional ethylenically unsaturated monomer b2), and 0 to 15% by weight of further ethylenically unsaturated monomers c) different from any of monomers a), b1) and b2), wherein the amounts of monomers a), b1), b2) and if present c) sum to 100 wt %.

19. The consolidated nonwoven according to claim 16, wherein the Polymer P is obtained by free radical aqueous emulsion polymerization of a monomer mixture of a. 75 to 99% by weight of styrene and butadiene, b. 1 to 10% by weight of one or more of N-methylolacrylamide and M-methyol-methacrylamide and c. ≥0 to 15% by weight of further ethylenically unsaturated monomers different from any of monomers a) and b), wherein the amounts of monomers a) to c) sum to 100 wt %.

20. The consolidated nonwoven according to claim 16, wherein the polymer P is obtained by free radical aqueous emulsion polymerization of a monomer mixture of 75 to 90% by weight of one or more of n-butyl acrylate and 2-ethylhexylacrylate (monomers a), 10 to 25% by weight of one or more carboxylic acid-functional ethylenically unsaturated monomer (monomer b) and 0 to 10% by weight of one or more of vinylsulfonic acid, acrylonitrile and methacrylonitrile (monomer c), in polymerized form, wherein the amounts of monomers a) to c) sum to 100 wt % and wherein the amount of the metal compound M is determined such that it is ≥0.1 and ≤0.4 mol based on one mol monomers b) in polymer P.

21. The consolidated nonwoven according to claim 16, wherein the polyvinylalcohol has a degree of hydrolysis of ≥80%.

22. The consolidated nonwoven according to claim 16, wherein the polyvinylalcohol has a molecular weight ≥40000 g/mol.

23. The consolidated nonwoven according to claim 16, wherein the wherein the starch compound S is a degraded starch.

24. A consolidated nonwoven according to claim 16, wherein the binder composition comprises: A) 1-99% by weight of polymer P, B) 1-70% by weight of polyvinylalcohol, C) 0-50% by weight of the starch compound S, and D) 0-10% by weight of the metal compound M, wherein the sum of the components A) to D) is 100% by weight.

25. The consolidated nonwoven according to claim 16, wherein the nonwoven comprises one or more of synthetic fibers, carbon fibers, glass fibers, ceramic fibers, mineral fibers and natural fibers.

26. The consolidated nonwoven according to claim 16, wherein the nonwoven comprises synthetic fibers selected from the group consisting of viscose, polyester, polyamide, polypropylene, polyethylene, polyacrylonitrile and polyvinyl chloride fibers.

27. The consolidated nonwoven according to claim 16, wherein nonwoven consists of a spunbond web or a staple fiber web, each with or without glass yarn reinforcement.

28. A process for producing a consolidated nonwoven according to claim 16, wherein an aqueous binder composition is applied to a nonwoven and the nonwoven thus obtained is subjected to a thermal treatment step at a temperature ≥110° C.

29. Use of the consolidated nonwoven according to claim 16, as reinforcing insert for bituminized roofing membranes.

30. An aqueous binder composition comprising a polymer P, a polyvinyl alcohol, optionally a starch compound S, and optionally at least one metal compound M selected from the group consisting of magnesium, calcium and zinc, in the form of an oxide, hydroxide, carbonate or bicarbonate, wherein the polymer P is obtainable by free radical aqueous emulsion polymerization of a monomer mixture of 75 to 99% by weight of one or more monomers a) selected from the group consisting of esters of one or more of acrylic and methacrylic acid with alkanols of 1 to 12 carbon atoms, aliphatic conjugated diene and aromatic vinyl compound, 1 to 25% by weight of one or more monomers b) selected from the group consisting of N-methylolacrylamide, N-methylolmethacrylamide, glycidyl meth-acrylate and carboxylic acid-functional ethylenically unsaturated monomers, and ≥0 to 15% by weight of one or more further ethylenically unsaturated monomer c) different from any of monomers a) and b) wherein the amounts of monomers a) to c) sum to 100 wt %.

31. The composition of claim 16, wherein the composition comprises at least one of: the starch compound S, and the at least one metal compound M.

32. The composition of claim 30, wherein the composition comprises at least one of: the starch compound S, and the at least one metal compound M.

Description

EXAMPLES

[0103] In the following all part and percentages are based on weight unless otherwise specified. The following materials were used: [0104] Web 1: a needled spunbond web based on polyethylene terephthalate fibers having a basis weight of 150 g/m.sup.2 [0105] Web 2: a needled and a glass fiber reinforced staple fiber web based on polyethylene terephthalate fibers having a basis weight of 90 g/m.sup.2 [0106] Dispersion 1: a thermally crosslinkable copolymer of acrylic ester and styrene (together 96% by weight) and N-methylolmethacrylamide (4% by weight); [0107] Dispersion 2: a thermally crosslinkable copolymer of styrene and butadiene (together 91% by weight) and N-methylolmethacrylamide (4% by weight); [0108] Dispersion 3: a thermally crosslinkable copolymer of acrylic ester and unsaturated carboxylic acids (together 87.9% by weight) and calcium hydroxide (5.5% by weight); [0109] Dispersion 4: a thermally crosslinkable copolymer of acrylic ester and styrene (together 85% by weight) and N-methylolmethacrylamide (5% by weight).

[0110] The weight of the monomers in percent is related to the total amount of monomers of the respective copolymer. All dispersions are anionically stabilized aqueous dispersion with a solid content in the range of 45-50% by weight. [0111] Starch 1: a hydroxypropylated potato starch having an average molecular weight of 1,769,000 g/mol, dissolved in boiling water, 20% by weight; [0112] Starch 2: a corn starch having an average molecular weight of 130,000 g/mol, dissolved in boiling water, 20% by weight [0113] Polyvinyl alcohol (PVOH) 1: fully hydrolyzed (according to data sheet 98.5-99.2 mol %) with an average molecular weight of 86,500 g/mol [0114] Polyvinyl alcohol 2: fully hydrolyzed (according to data sheet 98.5-99.2 mol %) with an average molecular weight of 29,500 g/mol [0115] Polyvinyl alcohol 3: fully hydrolyzed (according to data sheet 98.5-99.2 mol %) with an average molecular weight of 45,000 g/mol [0116] Polyvinyl alcohol 4: fully hydrolyzed (according to data sheet 98.5-99.2 mol %) with an average molecular weight of 57,000 g/mol [0117] Polyvinyl alcohol 5: fully hydrolyzed (according to data sheet 98.5-99.2 mol %) with an average molecular weight of 109,500 g/mol

[0118] Each polyvinyl alcohol (PVOH) was dissolved in boiling water, 20% by weight.

Determination of Solid Contents (SC):

[0119] The determination of solids content is based on a gravimetric method. 1-2 g of the dispersion (initial weight) are weighed on an analysis balance into a tarred aluminum dish. The dish is stored for 1 hour at 120° C. in a circulating air oven until constant mass is reached. After cooling to room temperature (23° C.) the final weight is determined again (weight after drying).

[0120] The ratio of the “weight after drying” to the “initial weight” multiplied by 100% gives the solid content in per cent.

[0121] In the following composition, the proportions by weight are based on the dry mass of the binder composition, i.e., without water. [0122] Binder composition A: a mixture of dispersion 1 and polyvinyl alcohol 1 with a ratio of 70/30 (solid/solid); [0123] Binder composition B: a mixture of dispersion 2, starch 1 and polyvinyl alcohol 1 with a ratio of 50:30:20 (solid/solid/solid); [0124] Binder composition C: a mixture of dispersion 2 and polyvinyl alcohol 1 with a ratio of 70/30 (solid/solid); [0125] Binder composition D: a mixture of dispersion 3, starch 2, and polyvinyl alcohol 1 with a ratio of 50/30/20 (solid/solid/solid) [0126] Comparative binder composition E: a mixture of dispersion 1 and a melamine formaldehyde resin with a solid content of 69% by weight), the mixture having a ratio (of 90/10 (solid/solid) [0127] Comparative binder composition F: a mixture of dispersion 2 and starch 1 with a ratio of 70/30 (solid/solid) [0128] Comparative binder composition G: a mixture of dispersion 4, starch 2, and a melamine formaldehyde resin with a solid content of 69% per weight, dispersion/starch/resin having a ratio of 39/35/26 (solid/solid/solid). [0129] Comparative binder composition H: a mixture of starch 1 and polyvinyl alcohol 1 with a ratio of 80/20 (solid/solid), according EP 3299514

Performance testing

Production of Impregnating Liquors

[0130] The impregnating liquors were produced from the inventive binder composition A-D and also the comparative binder composition E and F by adjusting these compositions to a solids content of 13% by weight by diluting with deionized water.

Production of Consolidated Nonwovens (Fiber Webs)

[0131] The consolidated fiber webs were produced by saturating the respective raw web 1 or 2 with the respective impregnating liquors A-D and E or F in the longitudinal direction by means of a foulard via bath impregnation. The impregnated fiber webs obtained were subsequently dried and cured within a drum dryer from Mathis, the drying temperature and feed rate were set to 200° C. and 0.9 m/min, respectively. Thus, a drying/crosslinking time of 3 minutes was achieved. The solid content of 13% by weight of each impregnating liquor combined with an individual foulard pressure resulted in a solid binder amount of 20% after drying related to the basis weight of the webs. [0132] inventive example 1 (IE1): web 2 was impregnated with binder composition A [0133] inventive example 2 (IE2): web 1 was impregnated with binder composition B [0134] inventive example 3 (IE3): web 1 was impregnated with binder composition C [0135] inventive example 4 (IE4): web 2 was impregnated with binder composition D [0136] inventive example 5 (IE5): web 1 was impregnated with binder composition A [0137] comparative example 1 (CE1): web 2 was impregnated with binder composition E [0138] comparative example 2 (CE2): web 1 was impregnated with binder composition F [0139] comparative example 3 (CE3): web 2 was impregnated with binder composition G [0140] comparative example 4 (CE4): web 1 was impregnated with binder composition H

Determination of Breaking Strength and Breaking Strains in Machine and Cross-Machine Direction (Tensile Test)

[0141] Breaking strengths in machine direction (MD) and cross-machine direction (CD) were determined for fiber webs IE1 to IE5 and CE1 to CE3 at room temperature and at 180° C. in accordance with DIN EN 29073 using a breaking machine from Zwick (model Z005). To this end, 270×50 mm.sup.2 strips were die-cut out of fiber webs IE1 to IE5 and CE1 to CE3 in the machine as well as cross-machine direction and clamped with a length of 200 mm into the pulling device.

[0142] For the tests at elevated temperatures a heating chamber was used. The individual specimen was clamped into the pulling device and the chamber was closed, after the temperature within the chamber stabilized at 180° C. the test started.

[0143] In each case, 5 separate measurements were carried out with a testing speed of 100 mm/min. By recording force and extension, breaking strengths in N/50 mm (F.sub.max), as well as force-extension-curves were determined. In case of a glass yarn reinforced nonwoven the force level of the glass yarn rupture (F.sub.glass) was additionally evaluated. Depending on the area weight of the fibrous web and the amount of reinforcing glass yarns either glass yarn rupture occurs prior to the total rupture of the remaining web or both effects happen simultaneously.

[0144] Regarding tensile tests higher breaking strengths imply a better material performance and therefore a better binder composition.

Determination of Thermal Dimensional Stability

[0145] The tests were carried out in accordance to DIN 18192. Specimens of 360×100 mm.sup.2 were diecut out in machine direction. In the specimen center a field of 100×100 mm.sup.2 was marked. Length and width values at 10 positions are determined. The temperature of the used heating chamber was set to 200° C. Within the chamber a laboratory stand was positioned. Clamping rails were fixed to both specimen ends. After opening the heating chamber, the specimen was connected with one clamping rail to the laboratory stand. The lower clamping rail was loaded with a constant mass and the chamber was closed, thus the loaded specimen was exposed to 200° C. for a time of 10 minutes. After that the specimen including the laboratory stand were removed from the chamber and the loaded specimen cooled down to ambient temperature for 5 minutes. Mass and clamped rails were removed and lengths and widths values of the marked field were determined and by means of the corresponding values prior to loading strains (eps.sub.long, eps.sub.trans) were calculated. The optimum values within the thermal dimensional stability tests would be zero, thus values of eps.sub.long and ep.sub.strans close to zero reveal a better thermal dimensional stability.

[0146] Within these tests web1 was loaded with 8 kg and web 2 with 6 kg.

TABLE-US-00001 TABLE 1 Results for tensile test and thermal dimensional stability of examples IE2, IE3, IE5 and CE2 (basis is web 1) with an area weight of the consolidated nonwoven of 186 g/m.sup.2 *stability at Tensile test, Tensile test, Tensile test Tensile test 200° C. RT MD RT CD 180° C. MD 180° C. CD eps.sub.long eps.sub.trans example F.sub.max F.sub.max F.sub.max F.sub.max [%] [%] IE3 652 458 339 265 4.9 −3.7 IE2 689 489 355 286 5.4 −4.6 CE2 642 465 285 249 5.6 −4.8 IE5 686 478 332 253 5.4 −4.7 CE4 646 448 325 250 5.0 −4.5 *thermal dimensional stability at 200° C.

TABLE-US-00002 TABLE 2 Results for tensile test and thermal dimensional stability of examples IE1, IE4 and CE1 und CE3 (basis is web 2) with an area weight of the consolidated nonwoven in the range from 110-130 g/m.sup.2 .sup.1)stability at Tensile test, Tensile test, Tensile test Tensile test 200° C. RT MD RT CD 180° C. MD 180° C. CD eps.sub.long eps.sub.trans example Wt.sup.2) F.sub.glass F.sub.max F.sub.max F.sub.max F.sub.max [%] [%] IE1 126 295 271 229 118 116 1.0 −0.6 CE1 129 284 241 170 124 85 1.4 −0.9 IE4 109 340 223 269 146 148 0.01 −0.05 CE3 110 345 183 203 150 113 0.06 −0.04 .sup.1)thermal dimensional stability at 200° C. .sup.2)web weight of the consolidated nonwoven

[0147] The results of the inventive examples reveal F.sub.max and—if existing—F.sub.glass values (in machine as well as cross-machine direction) than the comparative examples combined with lower eps.sub.long and eps.sub.trans values (improved thermal dimensional stability). Additionally, the recorded forceextension curves of the inventive binder compositions showed steeper curve progressions which means higher material stiffnesses.

Binder Compositions H-K with Different Polyvinyl Alcohol

[0148] In analogy to binder composition A, the binder compositions H to K were prepared as a mixture of 70 parts by weight dispersion 1 and 30 parts by weight of the respective polyvinyl alcohol (each calculated as solids), as shown in Table 3. The impregnating liquors were produced from the inventive binder composition H-K by adjusting these compositions to a solids content of 13% by weight by diluting with deionized water.

Fiber webs IE6 to IE8

[0149] Web 1 was impregnated, dried and hardened with the diluted binder compositions H to K thus obtained as described above.

TABLE-US-00003 TABLE 3 Results for tensile test and thermal dimensional stability of examples IE5 to IE9 (basis is web 1) with an area weight of the consolidated nonwoven of 186 g/m.sup.2 .sup.1)stability at Tensile test, Tensile test, Tensile test Tensile test 200° C. b.- MW of PVA RT MD RT CD 180° C. MD 180° C. CD eps.sub.long eps.sub.trans Web comp. PVA [g/mol] F.sub.max F.sub.max F.sub.max F.sub.max [%] [%] IE5 A 1 86,500 686 478 332 253 5.4 −4.7 IE6 H 2 29,500 615 415 268 210 5.4 −5.7 IE7 I 3 45,000 659 471 297 238 5.3 −5.1 IE8 J 4 57,000 658 478 332 246 5.4 −5.0 IE9 K 5 109,500 661 475 332 253 5.3 −4.0 .sup.1)thermal dimensional stability at 200° C.