Tape joint compound

Abstract

An aqueous tape joint compound including: an inorganic filler; an emulsion polymer binder; cellulose ether thickener; water; and from 0.01 to 1.3% by weight based on the weight of the aqueous joint compound, water-soluble polymer or salts thereof, the water-soluble polymer selected from the group consisting of (a) polymer consisting essentially of, as polymerized units, from 50% to 100%, by weight based on the weight of the polymer, acrylic acid, and from 0% to 50%, by weight based on the weight of the polymer, second monoethylenically unsaturated acid monomer, (b) diisobutylene-maleic anhydride polymer, and (c) mixtures thereof; the water-soluble polymer having a weight average molecular weight of from 1500 to 75,000 and a calculated Tg of from 80 C. to 250 C.; the aqueous tape joint compound being substantially free from calcium sulfate hemihydrate is provided.

Claims

1. An aqueous tape joint compound comprising: an inorganic filler; from 0.5 to 4% by weight as solid polymer based on the weight of said aqueous joint compound of an emulsion polymer binder; cellulose ether thickener; water; and from 0.01 to 1.3% by weight based on the weight of said aqueous joint compound, water-soluble polymer or salts thereof, said water-soluble polymer selected from the group consisting of (a) polymer consisting essentially of, as polymerized units, from 50% to 100%, by weight based on the weight of said polymer, acrylic acid, and from 0% to 50%, by weight based on the weight of said polymer, second monoethylenically unsaturated acid monomer, (b) diisobutylene-maleic anhydride polymer, and (c) mixtures thereof; said water-soluble polymer having a weight average molecular weight of from 1500 to 75,000 and a calculated Tg of from 80 C. to 250 C.; and wherein said aqueous tape joint compound is substantially free from calcium sulfate hemihydrate.

2. The aqueous tape joint compound of claim 1 wherein said water-soluble polymer has a weight average molecular weight of from 1700 to 50,000.

3. The aqueous tape joint compound of claim 1 wherein said water-soluble polymer consists essentially of polyacrylic acid.

4. The aqueous tape joint compound of claim 1 having a Braebender viscosity of from 400 to 800 BU.

5. A method for forming an aqueous tape joint compound comprising admixing an inorganic filler; from 0.5 to 4% by weight as solid polymer based on the weight of said aqueous joint compound of an emulsion polymer binder; cellulose ether thickener; water; and from 0.01 to 1.3% by weight based on the weight of said aqueous joint compound, water-soluble polymer or salts thereof, said water-soluble polymer selected from the group consisting of (a) polymer consisting essentially of, as polymerized units, from 50% to 100%, by weight based on the weight of said polymer, acrylic acid, and from 0% to 50%, by weight based on the weight of said polymer, second monoethylenically unsaturated acid monomer, (b) diisobutylene-maleic anhydride polymer, and (c) mixtures thereof; said water-soluble polymer having a weight average molecular weight of from 1500 to 75,000 and a calculated Tg of from 80 C. to 250 C.; and wherein said tape joint compound is substantially free from calcium sulfate hemihydrate.

6. The method of claim 5 wherein said water-soluble polymer is provided in solid powder form.

7. A method for providing a monolithic surface comprising (a) providing a first planar substrate having a first edge; (b) abutting a second edge of a second planar substrate, thereby forming a joint; (c) applying the aqueous tape joint compound of any of claims 1-4 to the joint; and (d) allowing the aqueous tape joint compound to dry.

8. The method according to claim 7 further comprising applying a joint tape to said joint prior to step (c) or embedded into the aqueous tape joint compound prior to step (d).

Description

EXPERIMENTAL TEST METHODS

(1) Unless otherwise indicated, all samples were tested as made, and not diluted.

(2) Viscosity

(3) Measured in Brabender units (BU) using ASTM Standard C474, 2011, Standard Test Methods for Joint Treatment Materials for Gypsum Board Construction, ASTM International, West Conshohocken, Pa., 2003, DOI: 10,1520/C0033-03, at the website www.astm.org. All samples were equilibrated and measured at 25 C.

(4) Weight Average Molecular Weight

(5) Weight average molecular weight herein is that determined by aqueous gel permeation chromatography (GPC) using an Agilent 1100 HPLC system (Agilent Technologies Santa Clara, Calif.) equipped with an isocratic pump, vacuum degasser, variable injection size auto-sampler, and column heater. The detector was a Refractive Index Agilent 1100 HPLC G1362A. The software used to chart weight average molecular weight was an Agilent ChemStation, version B.04.02 with Agilent GPC-add on version B.01.01. The column set was TOSOH Bioscience TSKgel G2500PWxl 7.8 mm ID30 cm, 7 m column (P/N 08020) (TOSOH Bioscience USA South San Francisco, Calif.) and a TOSOH Bioscience TSKgel GMPWxl 7.8 mm ID30 cm, 13 m (P/N 08025) column. A 20 mM Phosphate buffer in MilliQ HPLC Water, pH7.0 was used as the mobile phase. The flow rate was 1.0 ml/minute. A typical injection volume was 20 L. The system was calibrated using poly(acrylic acid), Na salts Mp 216 to Mp 1,100,000, with Mp 900 to Mp 1,100,000 standards from American Polymer Standards (Mentor, Ohio).

(6) Tape Bond Adhesion

(7) Using 0.635 mm (25/1000 inch) feeler gauges, the formulation was applied to a piece of wall board. A template was used to reproduce the exact same geometry. A piece of joint tape paper, making three replicates using the outer tape side (manufacturer recommended side) and three replicates using the inner tape side, was embedded in the formulation. The tape paper was 152.4 mm (6 inch) long, with 101.6 mm (4 inch) being embedded and 50.8 mm (2 inch) not embedded. The formulation was allowed to dry in a controlled environment at 21 C. (70 F.) and 50% relative humidity. Using the 50.8 mm (2 inch), non-embedded tail to hold on to, a tensile tester pulled apart the tape paper from the formulation in a 90 degree t-peel test and quantified the amount of force required to break the adhesion between the tape and the compound.

(8) Cracking

(9) Cracking was rated by drying the tape joint compound in a standard crack ring. Templates were fabricated from 6.35 mm Plexiglas. A 69.85 mm diameter circle was cut away from the Plexiglas. The template was placed on a piece of wall board. The formulation was spread into the 69.85 mm diameter, 6.35 mm deep cylinder and set-up in duplicate. The formulation was allowed to dry over night in a controlled environment at 21 C. (70 F.) and 50% relative humidity. After drying, the samples were rated for the visual degree of cracking observed and a numerical rating was generated according to the chart:

(10) TABLE-US-00001 Visual Degree of Cracking Numerical rating None 10 Trace 8 Slight 6 Moderate 4 Heavy 2 Performed in duplicate, average reported
Cratering

(11) Cratering was rated by using an automatic apparatus to drawdown the tape joint compound diluted with water to a 500 BU and 400 BU viscosity, respectively, over wallboard at a fixed thickness and time. This test was performed in duplicate and the test boards were dried overnight in a controlled environment at 21 C. (70 F.) and 50% relative humidity. The resultant dry joint compound drawdowns were rated for the visual degree of cratering observed and a numerical rating was generated according to the chart:

(12) TABLE-US-00002 Visual Degree of Cratering Numerical rating None 10 Trace 8 Slight 6 Moderate 4 Heavy 2 Performed in duplicate, average reported

(13) The following examples serve to illustrate the invention.

(14) Water-Soluble Polymers

(15) Water-soluble polymer A=Acrylic acid/maleic acid copolymer, neutralized form, sodium salt, Mw=1900.

(16) Water-soluble polymer B=poly(acrylic acid); Mw=4,500.

(17) Water-soluble polymer C is a diisobutylene-maleic anhydride copolymer (50/50, wt/wt), hydrolyzed, sodium salt, Mw=10,000.

(18) Water-soluble polymer D=poly(acrylic acid), neutralized form, sodium salt, Mw=3,700.

(19) Water-soluble polymer E=Acrylic acid/maleic acid copolymer (80/20, wt/wt); Mw=40,000.

(20) Water-soluble polymer F=Acrylic acid/maleic acid copolymer (70/30, wt/wt); Mw=70,000.

(21) Water-soluble polymer G=Acrylic acid/2-acrylamido-2-methyl propane sulfonic acid (70/30, wt/wt) copolymer, sodium salt, Mw=12,000

Examples 1-42 and Comparative Examples A-B

(22) Regular weight aqueous tape joint compound formulation for Examples 1-42 and Comparative Examples A-B.

(23) TABLE-US-00003 Ingredient Parts by weight Water 29.8% Calcium carbonate 61.9% Mica 4K 3.6% ATTAGEL 25 Clay 2.0% Biocide 0.1% Emulsion polymer, PVA 2.2% (60% solids) Cellulose ether thickener 0.4% Water-soluble polymer 0-1.3% Notes: Mica 4K, dry ground muscovite mica with 47 micron average particle size, product of Imerys Minerals, Ltd.; ATTAGEL 25 Clay, attapulgite clay with 15 micron average particle size, product of BASF GmbH.

(24) EXAMPLES 1-20 and COMPARATIVE EXAMPLE A. The aqueous tape joint compounds of Examples 1-20 and Comparative Example A contain WALOCEL MK25000 PFV (HPMC) (WALOCEL is a trademark of The Dow Chemical Co.) as the cellulose ether thickener. Table 1.1 provides the identification and level of water-soluble polymer of the Examples and results of the testing of viscosity (BU), adhesion, cracking and cratering.

(25) TABLE-US-00004 TABLE 1.1 Performance of tape joint compounds. % Peel Adhesion Water- Water- (lbs/in) Crater % soluble soluble Viscosity Bond Bond 500 400 Ex # Solids polymer polymer (BU) in out Total Crack BU BU Comp. A 69.4 0% 660 0.61 1.04 1.65 9 6.5 6 1 69.4 0.07% A 690 0.71 1.15 1.85 9.5 7 7.5 2 69.4 0.14% A 680 0.87 1.19 2.06 8 7.5 8 3 69.3 0.27% A 640 1.04 1.15 2.19 8.5 6.5 7 4 69.4 0.07% B 650 0.74 1.14 1.88 9 6.5 7.5 5 69.4 0.14% B 630 0.93 1.12 2.05 7 7.5 8 6 69.3 0.27% B 610 0.97 1.13 2.10 10 8 8.5 7 69.4 0.07% B powder 650 0.82 1.13 1.95 7.5 8.5 8 8 69.4 0.14% B powder 615 0.83 1.15 1.97 7.5 8.5 8.5 9 69.4 0.27% B powder 640 0.62 1.12 1.74 7 8 7.5 10 69.4 0.07% C 600 0.87 0.83 1.70 7 7.5 8.5 11 69.3 0.14% C 570 1.15 0.99 2.14 9 7.5 8.5 12 69.8 1.3% C 490 1.50 1.15 2.65 8 6 9 13 69.4 0.07% C powder 540 0.88 1.02 1.90 9.5 8 8 14 69.4 0.14% C powder 540 0.95 0.96 1.92 8 8 8.5 15 69.4 0.27% C powder 560 0.91 1.32 2.23 7 8.5 8 16 69.5 0.67% C powder 580 0.99 1.35 2.34 7 6.5 7 17 69.4 0.07% D 680 0.88 0.90 1.77 9 7 8.5 18 69.3 0.14% D 660 1.03 0.90 1.93 10 7 8 19 69.3 0.27% D 640 1.22 0.98 2.19 9 8.5 8.5 20 69.0 1.3% D 520 0.53 1.01 1.54 9 8 8.5

(26) EXAMPLES 21-42 and COMPARATIVE EXAMPLE B. The aqueous tape joint compounds of Examples 21-42 and Comparative Example B contain METHOCEL J75 MS-N(HPMC) (METHOCEL is a trademark of The Dow Chemical Co.) as the cellulose ether thickener. Table 21.1 provides the identification and level of water-soluble polymer of the Examples and results of the testing of viscosity (BU), adhesion, cracking and cratering.

(27) TABLE-US-00005 TABLE 21.1 Performance of tape joint compounds. Peel Adhesion % Water- Water- (lbs/in) Crater % soluble soluble Viscosity Bond Bond 500 400 Ex # Solids polymer polymer (BU) in out Total Crack BU BU Comp. B 69.4 0% 660 0.45 1.07 1.52 3 4.5 4.5 21 69.4 0.07% A 610 0.60 1.13 1.73 4 5 5 22 69.4 0.14% A 650 0.87 1.10 1.97 5 6 7 23 69.3 0.27% A 620 1.06 1.05 2.11 5 5.5 8 24 69.2 0.67% A 590 0.79 0.89 1.68 8 6 6 25 69.1 1.3% A 540 0.45 0.58 1.04 6 5.5 6.5 26 69.4 0.07% B 645 0.82 0.95 1.76 4 5 5 27 69.4 0.14% B 630 0.92 1.03 1.95 3 5 6 28 69.3 0.27% B 585 0.93 0.99 1.93 6 5.5 6 29 69.2 0.67% B 570 0.58 0.92 1.50 5.5 6 5 30 69.1 1.3% B 510 0.38 0.76 1.13 5.5 5 5.5 31 69.4 0.07% B powder 620 0.94 1.02 1.97 6.5 5 5 32 69.4 0.14% B powder 640 1.04 1.06 2.09 2 5.5 6 33 69.4 0.27% B powder 630 1.09 1.08 2.17 4 5 7 34 69.4 0.07% C 660 0.56 1.05 1.61 9.5 5 5 35 69.3 0.14% C 590 0.62 0.97 1.59 6 7 6.5 36 69.3 0.27% C 540 0.61 0.99 1.60 9.5 7 6 37 69.3 0.27% E 640 0.95 1.07 2.02 6 6 7 38 69.3 0.27% G 850 0.74 0.99 1.73 8 6.5 6.5 39 69.4 0.14% F 680 0.50 0.83 1.33 4.5 3 3 40 69.3 0.27% F 630 0.58 0.97 1.56 4.5 5 5 41 69.2 0.67% F 580 0.76 0.96 1.72 8 5 5 42 69.1 1.3% F 560 0.77 0.97 1.75 5 5.5 6.5

Examples 43-48 and Comparative Examples C-D

(28) Regular weight aqueous tape joint compound formulation for Examples 43-48 and Comparative Examples C-D.

(29) TABLE-US-00006 Use levels for Ingredient examples Water 29.1% Calcium carbonate 62.0% Mica 4K 3.6% ATTAGEL 25 Clay 2.0% Biocide 0.1% Latex, PVA (60% solids) 2.7% Thickener 0.4% Water-soluble polymer 0-0.27%

(30) EXAMPLES 43-45 and COMPARATIVE EXAMPLE C. The aqueous tape joint compounds of Examples 43-45 and Comparative Example C contain METHOCEL 240S(HPMC) as the cellulose ether thickener. Table 43.1 provides the identification and level of water-soluble polymer of the Examples and results of the testing of viscosity (BU), adhesion, cracking and cratering.

(31) TABLE-US-00007 TABLE 43.1 Performance of tape joint compounds Peel Adhesion % Water- Water- (lbs/in) Crater % soluble soluble Viscosity Bond Bond 500 400 Ex # Solids polymer polymer BU in out Total Crack BU BU Comp. C 69.8 0% 690 0.93 1.10 2.03 6 7 7.5 43 69.8 0.07% B 700 0.87 1.18 2.05 7 8.5 8 44 69.8 0.14% B 680 1.12 1.13 2.25 9 8.5 9 45 69.7 0.27% B 660 1.25 1.17 2.42 8 9 9

(32) EXAMPLES 46-48 and COMPARATIVE EXAMPLE D. The aqueous tape joint compounds of Examples 46-48 and Comparative Example D contain CELLOSIZE QP 52000 (HEC) (CELLOSIZE is a trademark of The Dow Chemical Co.) as the cellulose ether thickener. Table 46.1, below, provides the identification and level of water-soluble polymer of the Examples and results of the testing of viscosity (BU), adhesion, cracking and cratering.

(33) TABLE-US-00008 TABLE 46.1 Performance of tape joint compounds Peel Adhesion % Water- Water- (lbs/in) Crater % soluble soluble Viscosity Bond Bond 500 400 Ex # Solids polymer polymer BU in out Total Crack BU BU Comp. D 69.8 0% 660 0.37 0.37 0.74 10 3 4 46 69.8 0.07% B 680 0.40 0.49 0.89 7.5 4 6.5 47 69.8 0.14% B 670 0.42 0.52 0.94 7 4 6.5 48 69.7 0.27% B 640 0.51 0.68 1.19 9.5 3.5 5.5

Examples 49-56 and Comparative Example E

(34) Light weight aqueous tape joint compound formulation for Examples 49-56 and Comparative Example E.

(35) TABLE-US-00009 Use levels for Ingredient examples Water 40.0% Calcium carbonate 46.8% SIL-CEL 35/34 7.9% ATTAGEL 25 Clay 2.6% Biocide 0.1% Latex, PVA (60% solids) 2.2% Thickener 0.5% Water-soluble polymer 0-0.7% Note: SIL-CEL 35/34, expanded perlite with 40 micron particle size, product of Silibrico Corp.

(36) EXAMPLES 49-56 and COMPARATIVE EXAMPLE E. The aqueous tape joint compounds of Examples 49-56 and Comparative Example E contain METHOCEL J75MSN(HPMC) as the cellulose ether thickener. Table 49.1, below provides the identification and level of water-soluble polymer of the Examples and results of the testing of viscosity (BU), adhesion, cracking and cratering.

(37) TABLE-US-00010 TABLE 49.1 Peel Adhesion % Water- Water- (lbs/in) Crater Solids soluble soluble Viscosity Bond Bond 500 400 Ex # Wt % polymer polymer BU in out Total Crack BU BU Comp. E 59.1 0% 620 0.24 0.42 0.66 9.5 5 6 49 59.1 0.3 A 585 0.29 0.48 0.77 10 5 6.5 50 59.1 0.7 A 550 0.33 0.54 0.87 9.5 6.5 7.5 51 59.1 0.3 B 580 0.7 0.97 1.68 9.5 5 7 52 59.0 0.7 B 570 0.42 0.82 1.24 9 5.5 8 53 59.2 0.3 B 580 0.35 0.99 1.34 9.5 5.5 8 powder 54 59.0 0.3 C 500 0.25 0.56 0.81 9.5 7 7 55 59.1 0.1 D 560 0.24 0.51 0.75 9.5 6 7.5 56 59.1 0.3 D 550 0.70 1.07 1.77 9 6 8