Methacrylic acid polymer extended urea-formaldehyde resin composition for making fiberglass products

Abstract

The present invention provides methacrylic acid polymer modified aqueous urea formaldehyde resin (UF resin) binder compositions useful in making a treated glass mat, e.g. for roofing shingles, wherein the methacrylic acid polymer comprises the reaction product of at least 50 wt. %, based on the total weight of monomers used to make the methacrylic acid polymer, of methacrylic acid or its salts, or mixtures thereof, a water-soluble phosphorous or sulfur containing compound and the remainder of a carboxylic acid group containing monomer, such as acrylic acid. The methacrylic acid polymers have at least one of a phosphite group, hypophosphite group, phosphinate group, diphosphinate group, and/or sulfonate group and enable modified UF resins to have early strength development even when the binder compositions comprise from 0.1 to less than 5 wt. % of the polymer modifier, based on total solids of the UF resin and the polymer modifier.

Claims

1. An aqueous urea formaldehyde resin (UF resin) binder composition comprising the UF resin and from 0.1 to less than 5 wt. % of at least one polymer modifier, based on total solids of the UF resin and the polymer, wherein the polymer modifier is a methacrylic acid polymer that contains at least one acid group which is other than a carboxylic acid group and which is chosen from a phosphite group, hypophosphite group, phosphinate group, diphosphinate group, sulfonate group and combinations thereof, wherein the methacrylic acid polymer is the reaction product of 50 wt. % or more of methacrylic acid, a salt thereof, or mixtures thereof, based on the total weight of monomers used to make the methacrylic acid polymer up to 40 wt %, based on the total weight of monomers used to make the methacrylic acid polymer, of a carboxylic acid group containing monomer group consisting of acrylic acid, itaconic acid and maleic acid or its anhydride, and 4.0 to 25 wt %, based on total weight of monomer used to make the methacrylic acid polymer, of a water soluble phosphorous containing compound having an oxidation state of +3 or +1 or sulfur containing compounds having an oxidation state +4 or +1; and, further wherein the at least one polymer modifier has a weight average molecular weight of from 2,000 to 16,000.

2. The aqueous urea formaldehyde resin (UF resin) binder composition as claimed in claim 1, wherein the methacrylic acid polymer is the reaction product of 60 wt. % or more of methacrylic acid, a salt thereof, or mixtures thereof, based on the total weight of monomers used to make the methacrylic acid polymer.

3. The aqueous urea formaldehyde resin (UF resin) binder composition as claimed in claim 1, wherein the at least one polymer modifier has a weight average molecular weight of from 5,000 to 12,000.

4. The aqueous urea formaldehyde resin (UF resin) binder composition as claimed in claim 1, wherein the at least one polymer modifier is a methacrylic acid copolymer wherein the at least one acid group which is other than a carboxylic acid group is chosen from a group wherein a phosphorous atom is bound to two carbon atoms along the carbon chain, a terminal group, a pendant alkyl phosphinate, a pendant alkyl phosphonate, and combinations thereof.

5. A method of making an aqueous urea formaldehyde resin (UF resin) binder composition comprising the UF resin and from 0.1 to less than 5 wt. % of at least one methacrylic acid polymer modifier, based on total solids of the UF resin and the polymer modifier, wherein the polymer modifier is a methacrylic acid polymer that contains at least one acid group which is other than a carboxylic acid group and which is chosen from a phosphite group, hypophosphite group, phosphinate group, diphosphinate group, sulfonate group and combinations thereof, comprising; polymerizing in aqueous media a mixture of 50 wt. % or more of methacrylic acid or its salt, based on the total weight of monomers used to make the methacrylic acid polymer, up to 40 wt %, based on the total weight of monomer used to make the methacrylic acid polymer, of a carboxylic acid group containing monomer selected from a group consisting of acrylic acid, itaconic acid and maleic acid or its anhydride, and from 4.0 to 25.0 wt. %, based on the total weight of monomers used to make the methacrylic acid polymer, of at least one of a water-soluble compound chosen from a phosphorous containing compound in which the phosphorous is in the oxidation state of +3, a phosphorous containing compound in which the phosphorous is in the oxidation state of +1, a sulfur containing compound in which the sulfur is in the oxidation state of +4, a sulfur containing compound in which the sulfur is in the oxidation state of +1, and their salts; and, combining the result of the polymerization with urea formaldehyde resin.

6. The method of making an aqueous urea formaldehyde resin (UF resin) binder composition as claimed in claim 5, wherein the amount of the water-soluble compound ranges from 6.0 wt. % to 20 wt. %.

7. The method of making an aqueous urea formaldehyde resin (UF resin) binder composition as claimed in claim 5, wherein the water-soluble compound is chosen a hypophosphite compound, a bisulfite, a metabisulfite, and salts thereof.

8. The method of making an aqueous urea formaldehyde resin (UF resin) binder composition as claimed in claim 5, wherein the amount of the methacrylic acid polymer modifier ranges from 0.5 to less than 5 wt. % of at least one polymer modifier, based on total solids of the UF resin and the polymer modifier.

9. A method of using the aqueous urea formaldehyde resin (UF resin) binder composition as claimed in claim 1, comprising; applying the aqueous urea formaldehyde resin binder composition to or treating with the aqueous urea formaldehyde resin composition a wet laid continuous glass fiber mat; and, heating to cure the aqueous urea formaldehyde resin composition to form a treated glass mat.

10. A treated glass mat made by the method as claimed in claim 9.

Description

EXAMPLES

(1) In the examples and Tables 1 and 2 that follow, the following abbreviations were used:

(2) AA: acrylic acid, MAA: methacrylic acid, S: Styrene, MAAn: methacrylic anhydride, SMBS: sodium metabisulfite, SHP: sodium hypophosphite.

(3) In the examples that follow, the following test methods were used.

(4) Tensile Strength: The aqueous curable compositions were evaluated for dry and wet tensile strength on glass microfiber filter sheets (20.325.4 cm, Cat. No. 1820-866, Whatman International Ltd., Maidstone, England). Each sheet was dipped in each binder composition, placed between two cardboard sheets of similar dimensions, and run through a roll padder with roll pressure of 68.9 kPa (10 psi). The coated sheets were then dried by heating at 90 C. for 1.5 minutes in a Mathis oven. Post drying weight was determined to calculate binder add-on (15%+/2% by weight binder add-on). Dried sheets were then cured in a Mathis oven at a temperature of 190 C. for 60 sec and 180 sec, as indicated. The cured sheets were cut into 2.54 cm (1 in) by 10.16 cm (4 in) strips and tested for tensile strength in the machine direction using a Thwing Albert Tensile Tester (Thwing Albert Instrument Company, West Berlin, N.J.) equipped with a 1 kN load cell. The fixture gap was 2.54 cm (1 in) and the crosshead speed was 2.54 cm/min (1 in/min). Strips were tested either as is at room temperature conditions (Room Temperature Tensile Strength, RT-TS) or immediately after 30 minutes of immersing in water which is maintained at a temperature of 80 C. (How-Wet Tensile Strength, HW-TS). Tensile strengths were recorded as the peak force measured during parting. Data reported are averages of values recorded from measuring 10 treated and cured strips per filter sheet for each binder composition tested. Acceptable values for Room Temperature tensile strength fully cured at 180 seconds, are those higher than 40 N, or, preferably, above 45 N. Acceptable values for How-Wet tensile strength fully cured at 180 seconds are those higher than 5.0 N, or, preferably, above 7.0 N.

(5) In the Examples 1 to 4, the Comparative Examples 1C, 2C and 3C and the Control that follow, urea formaldehyde (UF) supplied at 65.5% solids by weight was blended with the following aqueous polymer solutions by simple mixing using a Caframo type RZR50 stirrer (Warton, Ontario, Calif.) equipped with a 2.54 cm diameter stirring blade and agitated to achieve a stable vortex for 10 minutes, at ambient temperature conditions. The binder was then diluted with water to a solids content of 15 wt. %:

Control Example

(6) None;

Example 1

(7) 1 wt. % on solids of a polymethacrylic acid (homopolymer) made from 89.29 wt. % MAA, 2.68% initiator and 8.03 wt. % SHP, 5,000 Mw;

Example 2

(8) 1 wt. % on solids of a polymethacrylic acid made from 92.81 wt. % MAA, 1.39% initiator and 5.80 wt. % SHP, 10,000 Mw;

Example 3

(9) 1 wt. % on solids of a polymethacrylic acid made from 86.71 wt. % MAA, 1.46% initiator and 11.83 wt. % SMBS, 10,000 Mw;

Example 4

(10) 1 wt. % on solids of a methacrylic acid copolymer made from 42.59 wt. % AA, 50.87 wt. % MAA, 2.34% initiator and 4.20 wt. % SHP, 16,000 Mw;

Example 1C

(11) 1 wt. % on solids of a polyacrylic acid made from 85.86 wt. % AA, 0.74% initiator, 5.72 wt. % NaOH and 7.68 wt. % SMBS, 3,700 Mw;

Example 2C

(12) 1 wt. % on solids Acrysol G111 poly-ethylacrylate/methacrylic acid emulsion copolymer 54 EA/46MAA/NH.sub.4OH, 300,000 Mw (Dow Chemical Co., Midland, Mich.); and,

Example 3C

(13) 1 wt. % on solids SMA 1000H equimolar styrene-maleic anhydride solution polymer 36% solids with 5,500 Mw, (Cray Valley HSC, Exton, Pa.)

(14) TABLE-US-00001 TABLE 1 Polymeric Binder Composition and Room Temperature Tensile Strength Modifier Chain Level, Molecular Polymer Transfer % s/s in Wt., RT-TS Std RT-TS Std. Example Composition Agent UF resin g/mole (60 sec), N Dev., N (180 sec), N Dev., N Control 35.7 7.3 37.3 5.6 1 p-MAA SHP 1 5,000 49.4 8.8 57.5 6.5 2 p-MAA SHP 1 10,000 54.8 1.46.3 59.6 5.0 3 p-MAA SMBS 1 10,000 52.0 4.9 51.6 8.9 4 p-MAA SHP 1 16,000 42.7 9.5 44.9 6.4 5 p-AA/MAA SHP 1 9,500 47.9 7.3 53.4 8.1 1C p-AA SMBS 1 3,700 46.1 4.3 47.9 4.7 2C EA/MAA SMBS 1 300,000 38.5 19.4 50.9 6.4 3C Sty/MAAn 1 1,000 45.5 3.4 46.9 5.8

(15) TABLE-US-00002 TABLE 2 Hot-Wet Tensile Strength Std. HW-TS.sub.t HW-TS.sub.t Dev., (180 sec), Std. Example (60 sec), N N N Dev., N Control 1.5 0.8 4.6 1.2 1 3.8 1.2 10.4 1.9 2 6.7 1.0 11.6 1.9 3 3.6 0.5 5.5 1.8 4 2.8 0.6 7.5 1.8 5 4.2 1.2 10.8 2.8 1C 1.8 0.7 4.4 1.5 2C 3.0 1.2 8.9 1.8 3C 2.0 0.8 4.6 0.8

(16) As shown in Tables 1 and 2, above, the inventive methacrylic acid polymers of Examples 1, 2, 3 and 4 when used in very low proportions of 1 wt. % based on total polymer and UF resin solids, gives at least the room temperature tensile strength of any of the polymers in Comparative Examples 1C, 2C and 3C; however, the Inventive Examples 1, 2, 3 and 4 all exhibit superior hot wet tensile strength when compared to the Comparative Examples with no phosphorus acid group or sulfonate group containing polymer. Observed with a range of phosphorus acid group containing methacrylic acid polymers and copolymers having a range of molecular weights, especially in the preferred 4,000 to 12,000 range, the improved hot wet tensile strength is particularly strong after just 60 seconds of cure. This data suggests the invention enables the desired development of early cure strength during the processing of glass mats made with the binder compositions.

(17) In comparison to the comparative Example 1C and 3C solution polymers which are water soluble polymers, it is not expected that one would see the improved hot wet tensile strength shown in inventive Example 2 where the polymer modifier is a solution polymer.