Molding a lightweight cast acoustical product
View Patent ↗A lightweight cast article that is made by the method of the present invention. A foamed acoustical product is prepared by blending a starch with cold water, then heating the starch/water blend to form a starch gel. Mineral wool is added to the starch gel to form a pulp and the pulp is wet-mixed until wool nodules are formed. The pulp is then combined with a surfactant and an amount of foam water. The foaming agent is selected from the group consisting of a linear sodium dodecylbenzene sulfonate, a cocamidopropyl betaine, a cocamidopropyl hydroxysultaine, their salts and mixtures thereof. Mixing of the foaming agent and pulp continues to form a foamed pulp. The foamed pulp is cast into a mold and allowing the foamed pulp to dry forming a foamed product. The foamed product is removed from the mold.
1. A method of making a foamed acoustical product comprising:
blending a starch with cold water;
heating the starch/water blend to form a starch gel;
adding mineral wool to the starch gel to form a pulp;
wet mixing the pulp until wool nodules are formed;
combining a surfactant with an amount of foam water, said surfactant being selected from the group consisting of a linear alkylbenzene sulfonate, a cocamidopropyl betaine, a cocamidopropyl hydroxysultaine, their salts and mixtures thereof;
mixing the surfactant, foam water and pulp to form a foamed pulp;
casting the foamed pulp into a mold;
allowing the foamed pulp to dry forming a foamed product;
removing the foamed product from the mold.
2. The method of claim 1 wherein the product of said method is free of perlite addition.
3. The method of claim 1 wherein the starch of said blending step comprises a vegetable starch.
4. The method of claim 3 wherein the vegetable starch of said blending step further comprises one of the group selected from corn, potato, wheat and tapioca starch.
5. The method of claim 4 wherein the vegetable starch is preferably a cross-linked corn starch.
6. The method of claim 1 wherein said mixing step comprises making a preformed foam and mixing the preformed foam into the wet pulp.
7. The method of claim 1 wherein said incorporating step further comprises adding a surfactant solution to the wet pulp and agitating the wet pulp to form the foamed pulp.
8. The method of claim 1 wherein said casting step comprises casting a panel.
9. The method of claim 1 wherein said combining step further comprises mixing the surfactant, water and pulp in a ribbon mixer.
10. The method of claim 1 wherein said heating step comprises adding steam to the starch/water mixture.
11. The method of claim 1 wherein the mineral wool of said adding step is added as fibrous mineral wool.
12. The method of claim 1 wherein said blending step further comprises blending fillers and boric acid with the starch/cold water mixture.
13. The method of claim 12 wherein the filler of said blending step comprises stucco.
14. The method of claim 1 further comprising texturizing the surface of the product.
15. A foamed acoustical product comprising: a dried structure of mineral wool, the spaces between the mineral wool fibers being filled with dried starch gel having voids therein, an interior surface of said voids being coated with a film selected from the group consisting of a linear alkylbenzene sulfonate, a cocamidopropyl betaine, a cocamidopropyl hydroxysultaine, their salts and mixtures thereof; said mineral wool being in the form of wool nodules of less than or equal to 3 mm; and
wherein said product has a density of at least 16 pounds per ft 3 and a hardness of at least 80 lbs force.
16. The product according to claim 15 further comprising at least one of the group consisting of gypsum, boric acid and mixtures thereof.