Expandable Joint Compound Composition and Method of Making Same

Abstract

A joint compound formulation is a mixture of a clay, cellulose ethers, expanded perlite, an adhesive, limestone, water, and a surfactant. The surfactant includes an alkyl trisiloxane. In addition a foam stabilizer, sodium dodecyl diphenyl ether disulfonate, may be added to the formulation.

Claims

1. In a joint compound formulation having at least: a. a clay; b. a thickener; c. expanded perlite; d. an adhesive; e. limestone; and f. water; an improvement comprising the addition of a surfactant.

2. The joint compound formulation of claim 1, wherein the surfactant is an alkyl trisiloxane.

3. The joint compound formulation of claim 2, wherein the alkyl trisiloxane makes up between 0.005% and 0.2% by weight of the formulation.

4. The joint compound formulation of claim 2, wherein the formulation further includes a gemini surfactant.

5. The joint compound formulation of claim 4, wherein the gemini surfactant is sodium dodecyl diphenyl ether disulfonate.

6. The joint compound formulation of claim 2, wherein the formulation further includes a foam stabilizer surfactant.

7. The joint compound formulation of claim 6, wherein the foam stabilizer surfactant is sodium dodecyl diphenyl ether disulfonate.

8. The joint compound formulation of claim 7, wherein sodium dodecyl diphenyl ether disulfonate makes up between 0.01% and 0.3% by weight of the formulation.

9. A method for formulating a joint compound formulation having at least the following ingredients: a. a clay; b. a thickener; c. expanded perlite; d. an adhesive; e. limestone; and f. water; comprising the steps of: i. mixing the ingredients to create mixed ingredients; and ii. adding a surfactant to the formulation.

10. The method for formulating a joint compound formulation of claim 9, wherein the surfactant is an alkyl trisiloxane.

11. The method for formulating a joint compound formulation of claim 10, wherein the alkyl trisiloxane makes up between 0.005% and 0.2% by weight of the formulation.

12. The method for formulating a joint compound formulation of claim 10, wherein the formulation further includes a gemini surfactant.

13. The joint compound formulation of claim 12, wherein the gemini surfactant is sodium dodecyl diphenyl ether disulfonate.

14. The method for formulating a joint compound formulation of claim 10, wherein the formulation further includes a foam stabilizer surfactant.

15. The method for formulating a joint compound formulation of claim 14, wherein the foam stabilizer surfactant is sodium dodecyl diphenyl ether disulfonate.

16. The method for formulating a joint compound formulation of claim 15, wherein sodium dodecyl diphenyl ether disulfonate makes up between 0.01% and 0.3% by weight of the formulation.

Description

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] For example, Table 1 below shows a representative conventional joint compound formula, PR-1.

TABLE-US-00001 TABLE 1 Quantity Ingredient (kilograms) Starch 0.4 Clay 3 Thickener 0.35 Expanded 6.2 perlite Limestone 47.8 Biocide 0.19 Latex 2.5 Water 39.56 Total Weight 100 Characteristics Viscosity, BU 360 Density, g/ml 1.16

[0016] As shown in Table 2 below, the addition of the surfactant system to PR-1 (with mixing) to create PR-1-EXP results in a reduction in density from 1.16 g/ml to 0.98 g/ml as well as a reduction in viscosity from 360 BU to 302 BU. The reduction in density translates to an 18.40% increase in volume for the same weight of product.

TABLE-US-00002 TABLE 2 Dosage (actives) Range Product - Quantity (% by weight of (% by weight PR-1-EXP (grams) PR-1) of PR-1) PR-1 322.43 Silsurf A008-UP 0.097 0.03 0.005-0.40 Dowfax 2A1 0.161 0.02 0.005-0.50 Total Weight 322.688 Characteristics Viscosity, BU 302 Density, g/ml 0.98

[0017] An important performance characteristic of joint compounds is drying shrinkage. Lower shrinkage is generally desirable because it translates to greater coverage for a given volume of joint compound. Conversely, it means that fewer coats of the joint compound would be required to achieve the desired surface smoothness. With the inventive surfactant system, an unexpected reduction in shrinkage results.

[0018] Shrinkage testing was carried out in duplicates, and the results are shown in Table 3. Between PR-1 and PR-1-EXP, the average shrinkage value fell from 21.80% to 17.80%. Water was added to PR-1 in order to bring its viscosity down to that of PR-1-EXP (302 BU). The average value of the new watered-down PR-1 displayed an even higher average shrinkage value of 23.7%. Therefore, at equivalent viscosity, there was a roughly 25% reduction in shrinkage between watered down PR-1 and PR-1-EXP which contained the inventive surfactant system.

TABLE-US-00003 TABLE 3 Shrinkage results for PR-1 samples Viscosity Product (BU) Shrinkage-1 Shrinkage-2 Average PR-1 360 21.7% 21.8% 21.8% PR-1-EXP 302 18.6% 16.9% 17.8% PR-1 (watered down) 302 23.5% 23.9% 23.7%

[0019] Shrinkage data for the joint compound after volumetric expansion was essentially unchanged compared to the original unexpanded joint compound which suggests that the microbubbles within the inventive expanded joint compound were of relatively sound structural integrity. A volumetric expansion of the inventive joint compound coupled with lower shrinkage translates into greater coverage for an initial volume of the corresponding unmixed, unexpanded inventive joint compound versus conventional joint compounds.

[0020] The surfactant can be dry mixed with the ingredients before the addition of water in a mixer. The surfactant can be dosed into the joint compound inside the mixer along with other ingredients. The surfactant can be added to the mixed ingredients upon exiting the mixer without additional mixing. Particularly, when packaging the joint compound in each individual container the surfactant can be added to the container while the container is being filled with joint compound. For example, one could situate a precision fluid dispenser in close proximity to a spout where the joint compound emerges to fill the container. The precision fluid dispenser would spray measured quantities of each surfactant into the container. An example of a precision fluid dispenser that could be employed for this is ECO-DUO which is manufactured by ViscoTec Pumpen-u. Dosiertechnik GmbH, 84513 Töging a. Inn, Germany. Another example is the Valvemate 8000 dispensing system by Nordson EFD LLC, USA.

[0021] Using the precision fluid dispenser, the surfactant could be added to an empty container prior to being filled with the joint compound comprising the mixed ingredients. The surfactant could be added to the container when the container is partially filled with the joint compound comprising the mixed ingredients to a predetermined level (for example, 50% of the final container volume). The surfactant could be added to the container when the container is essentially full of the joint compound comprising the mixed ingredients. The surfactant could also be added to the container at multiple fill levels.