AQUEOUS BINDER FORMULATION

Abstract

Aqueous binder formulation comprising a copolymer having a glass transition temperature 80 C., a polyol compound and a phosphorus compound.

Claims

1: An aqueous binder formulation, comprising: a) a copolymer A, comprising, in polymerized form, 20% and 50% by weight of at least one ,-monoethylenically unsaturated C.sub.3- to C.sub.6-monocarboxylic acid (A1) and 50% and 80% by weight of at least one other monoethylenically unsaturated compound (A2), wherein a total amount of A1 and A2 is 100% by weight, the copolymer A has a weight-average molecular weight in a range of from 5000 to 20 000 g/mol, the copolymer A has a glass transition temperature Tg in a range of 80 C., measured according to DIN EN ISO 11357-2 (2013-09), and 70 mol % of carboxyl groups present in the copolymer A have been neutralized with a volatile base; b) an organic compound which comprises at least 2 hydroxyl groups (polyol B), wherein an amount of the polyol B is determined such that a molar ratio of carboxyl groups present in the copolymer A to hydroxyl groups present in the polyol B is in a range of from 10:1 to 1:1; and c) a phosphorus-containing compound (phosphorus compound C), wherein an amount of the phosphorous compound is 3% and 20% by weight based on an amount of A1 present in the copolymer A in polymerized form.

2: The aqueous binder formulation of claim 1, wherein the copolymer A comprises, in polymerized form, as A2; 50% and 80% by weight of at least one monoethylenically unsaturated aromatic compound (A2-1) and 0% and 40% by weight of at least one other monoethylenically unsaturated compound distinct from A1 and A2-1, wherein a total amount of A2-1 and A2-2 is not more than 80% by weight of the total amount of A1 and A2.

3: The aqueous binder formulation of claim 1, wherein the copolymer A comprises, in polymerized form, acrylic acid and/or methacrylic acid as A1 and, as A2, styrene and/or -methylstyrene (A2-1) and methyl methacrylate, n-butyl acrylate and/or 2-ethylhexyl acrylate (A2-2).

4: The aqueous binder formulation of claim 1, wherein the copolymer A comprises in polymerized form, as A2: at least one monoethylenically unsaturated aromatic compound (A2-1), and at least one other monoethylenically unsaturated compound distinct from A1 and A2-1 (A2-2), wherein an amount of A1 is 30% and 45% by weight, an amount of A2-1 is 55% and 70% by weight and a amount of A2-2 is 0% and 20% by weight.

5: The aqueous binder formulation of claim 1, wherein the copolymer A comprises, in polymerized form, 30% and 45% by weight of acrylic acid, 20% and 65% by weight of styrene, 0% and 40% by weight of -methylstyrene and 0% and 20% by weight of methyl methacrylate, n-butyl acrylate and/or 2-ethylhexyl acrylate.

6: The aqueous binder formulation of claim 1, wherein an alkanolamine is employed as the polyol B.

7: The aqueous binder formulation of claim 1, wherein an amount of the polyol B is determined such that a molar ratio of carboxyl groups present in the copolymer A to hydroxyl groups present in the polyol B is in a range of from 2.5:1 to 1.1:1.

8: The aqueous binder formulation of claim 1, wherein sodium hypophosphite and/or sodium hypophosphite monohydrate is (are) employed as the phosphorus compound C.

9: The aqueous binder formulation of claim 1, wherein an organic or inorganic basic compound having a boiling point 110 C. at 1.013 bar (absolute) is employed as the volatile base.

10: The aqueous binder formulation of claim 1, wherein the copolymer A has been produced in bulk or optionally in the presence of a solvent by polymerization of A1 and A2 at a temperature in a range of from 160 C. to 310 C. employing at least one continuously operated stirred tank reactor.

11: A process for producing the aqueous binder formulation of claim 1, the process comprising, in a reaction vessel: initially charging water and the copolymer A at room temperature, to obtain a mixture of water and the copolymer A, then inerting the reaction vessel with nitrogen, then heating the mixture of water and the copolymer A, with stirring, to a temperature in a range of from 50 C. to 90 C., then adding, at said temperature with stirring, the volatile base to the mixture of water and the copolymer A, to obtain a reaction mixture, and then adding the polyol B and the phosphorus compound C to the reaction mixture with stirring, before or after cooling to room temperature.

12: A process for producing a molding from a granular and/or fibrous substrate, the process comprising obtaining the aqueous binder formulation of claim 1.

13: A process for producing a molding from agranular and/or fibrous substrate, the process comprising applying the aqueous binder formulation of claim 1 to the granular and/or fibrous substrate, optionally shaping the thus-treated granular and/or fibrous substrate and subsequently subjecting the thus-obtained granular and/or fibrous substrate to thermal treatment at a temperature in a range of 110 C.

14: The process of claim 13, wherein an amount of aqueous binder formulation is determined such that 1 and 100 g of binder (corresponding to a total amount of the copolymer A, the polyol B and the phosphorus compound C calculated as solids) is employed per 100 g of granular and/or fibrous substrate.

15: A shaped body, obtainable by the process of claim 13.

Description

EXAMPLES

[0118] To produce the aqueous binder liquors the copolymers A1 to A5 and V1 and V2 were employed, the production of which employed the constituents reported in table 1 which follows according to the procedure disclosed in U.S. Pat. No. 4,529,787 and the characterization of which is likewise reported in table 1 which follows.

TABLE-US-00001 TABLE 1 Characterization of copolymers A1 to A5 and V1 and V2 used for producing the binder liquors. Copolymer A1 V1 V2 A2 A3 A4 A5 Constituent: acrylic acid [% by wt] 45 34 9.6 38 40 39 30 styrene [% by wt] 33 24.4 62 21 54 36 -methylstyrene [% by wt] 45 33 27 7 29 methyl methacrylate [% by wt] 10 50.4 10 N-butyl acrylate [% by wt] 15.6 5 2-ethylhexyl acrylate [% by wt] 2 Polymer properties: weight average molecular weight [Mw] 5500 1690 15 630 6930 13 290 16 890 17 160 glass transition temperature 121 56 80 123 97 88 128 [ C.]

[0119] To produce the binder liquors the copolymers A1 to A5 and V1 and V2 were initially charged into a stirred tank at room temperature together with deionized water, the stirred tank is then inertized with nitrogen, copolymer A/water mixture is then heated to a temperature (dependent on the particular copolymer A) in the range from 50 C. and 90 C. with stirring, a 25% by weight aqueous solution of ammonia as the volatile base was then added with stirring and the obtained mixture was stirred at this temperature for about 2 to 3.5 hours to at least partially dissolve the respective copolymer A and disperse any remaining residue. The respective reaction mixture was subsequently cooled back down to room temperature. The thus-obtained aqueous copolymer systems are referred to as copolymer solutions A1 to A5 and V1 and V2 according to the employed copolymer A. The components employed to produce the copolymer solutions A1 to A5 and V1 and V2 having a copolymer content of 27% by weight are listed in table 2 which follows.

TABLE-US-00002 TABLE 2 List of components employed to produce copolymer solutions A1 to A5 and V1 and V2 [in % by wt] Copolymer solution Constituent A1 V1 V2 A2 A3 A4 A5 copolymer A 27.0 27.0 27.0 27.0 27.0 27.0 27.0 ammonia solution 11.5 8.7 2.5 9.7 10.2 9.9 7.6 deionized water 61.5 64.3 70.5 63.3 62.8 63.1 65.4

[0120] Using the copolymer A1 two further copolymer solutions were furthermore produced analogously to the production of the copolymer solution A1, wherein one was made up with 27.0% by weight of copolymer A1, 27.0% by weight of a 25% aqueous solution of sodium hydroxide and 46.0% by weight of deionized water, corresponding to copolymer solution 33, and the other is made up with 27.0% by weight of copolymer A1, 17.1% by weight of triethylamine and 55.9% by weight of deionized water, corresponding to copolymer solution A6.

Performance Tests:

[0121] To produce the aqueous binder liquor concentrates 1850 g of the respective abovementioned 27% by weight aqueous copolymer solutions A1 to A6 and V1 to V3 were initially charged in a 5 l beaker at room temperature, the amount of crosslinker triethanolamine (TEA) or glycerol and sodium hypophosphite (SHP) indicated in table 3 was added with stirring and the mixture was mixed until homogeneous. 0.3% by weight of 3-aminopropyltriethoxysilane based on the solids content (sum of nonaqueous components) of the respective binder liquor concentrate was then added to these mixtures and the mixture was then mixed until homogeneous by stirring. The respective binder liquor concentrates obtained were subsequently adjusted to a copolymer solids content of 4% by weight by addition of deionized water. The thus-obtained homogeneous mixtures are referred to as binder liquors C1 to C10 and V1 to V6.

TABLE-US-00003 TABLE 3 Formulation of binder liquor concentrates Binder liquor copolymer concentrate solution crosslinker SHP V1 A1 V2 A1 60 g TEA V3 A1 15 g V4 V3 60 g TEA 15 g V5 V1 60 g TEA 15 g V6 V2 60 g TEA 15 g C1 A1 60 g TEA 15 g C2 A1 15 g TEA 15 g C3 A1 120 g TEA 15 g C4 A1 60 g TEA 30 g C5 A6 60 g TEA 15 g C6 A1 60 g glycerol 15 g C7 A2 60 g TEA 15 g C8 A3 60 g TEA 15 g C9 A4 60 g TEA 15 g C10 A5 60 g TEA 15 g

[0122] Nonwoven glass fiber fabrics (5746 cm) from Whatman, GF/A No. 1820-915, having a basis weight of 53 g/m.sup.2 were employed to produce the moldings.

[0123] To apply the binder liquors (impregnation), the glass fiber nonwoven fabrics were passed longitudinally through the abovementioned 4% by weight aqueous binder liquors C1 to C10 and V1 to V6 using a continuous PES sieve belt at a belt speed of 60 cm per minute. By subsequent aspiration of the aqueous binder liquors the wet application rate was adjusted such that 10.8 g/m.sup.2 of copolymer (calculated as solids) were present in the nonwoven glass fiber fabric. The thus obtained impregnated nonwoven glass fiber fabrics were dried and cured for 3 minutes at 180 C. in a Mathis oven using a plastic mesh as a support at maximum hot air flow. After cooling to room temperature test strips having dimensions of 24050 mm were cut to size in the longitudinal fiber direction. The obtained test strips were subsequently stored for 24 hours in a climate controlled room at 23 C. and 50% relative atmospheric humidity. The nonwoven glass fiber fabric test strips obtained using the employed binder liquors C1 to C10 and V1 to V6 are hereinbelow referred to as test strips C1 to C10 and V1 to V6.

Wet Tear Strength Determination

[0124] To determine the wet tear strength the respective test strips were stored in deionized water at 80 C. for 15 minutes before excess water was dabbed off with a cotton fabric prior to measurement. Determination of tear strength was carried out on a Zwick-Roell Z005 tensile tester. Test strips C1 to C10 and V1 to V6 were introduced vertically into a clamping device such that the free clamped length was 200 mm. The clamped test strips were subsequently pulled apart in opposite directions at a speed of 25 mm/minute until the test strips tore. The higher the force required to tear the test strips, the better the assessment of the corresponding tear strength. 5 measurements were carried out in each case. The values reported in table 4 are the averages of the measurements obtained in each case.

TABLE-US-00004 TABLE 4 Summary of wet tear strength results [Values reported in N/50 mm in each case] Test strip wet tear strength V1 17 V2 22 V3 22 V4 2 V5 21 V6 31 C1 78 C2 70 C3 79 C4 93 C5 71 C6 35 C7 64 C8 65 C9 71 C10 61

[0125] Comparison of the wet tear strength results shows that the values for the inventive examples C1 to C10 are markedly higher than the values for the corresponding comparative examples V1 to V6.