Strengthened, light weight wallboard and method and apparatus for making the same

• US 6,340,388 B1
• Filed: 04/12/2000
• Issued: 01/22/2002
• Est. Priority Date: 11/18/1998
• Status: Expired due to Fees

• Current Assignee: Innovative Technologies Enterprises Corporation
• Original Assignee: Advanced Construction Materials Corporation
• Inventors: Luongo, Joseph S.
• Primary Examiner(s): Green, Anthony
• Application Number:
  US09/547,615
• Time in Patent Office: 650 Days
• Field of Search: 106/672, 106/675, 106/677, 106/680, 106/698, 106/778, 156/39, 156/45, 156/346, 524/423, 524/444, 428/449, 428/537.7
• US Class Current: 106/675
• CPC Class Codes: B28B 11/24 for curing, setting or hardening processes for influencing or modifying the setting or hardening ability of mortars, concrete or artificial stone compositions, in general C04B40/00
• CPC Class Codes: B28B 15/00 General arrangement or layout of plant ; Industrial outlines or plant installations
• CPC Class Codes: B28B 19/0092 to webs, sheets or the like, e.g. of paper, cardboard
• CPC Class Codes: B28B 23/0087 Lightweight aggregates for making lightweight articles
• CPC Class Codes: B29C 67/245 for making articles of indefinite length
• CPC Class Codes: B32B 29/00 Layered products comprising a layer of paper or cardboard
• CPC Class Codes: C04B 14/185 expanded
• CPC Class Codes: C04B 2111/0062 Gypsum-paper board like materials
• CPC Class Codes: C04B 22/0013 Boron compounds
• CPC Class Codes: C04B 24/2623 Polyvinylalcohols; Polyvinylacetates
• CPC Class Codes: C04B 24/38 Polysaccharides or derivatives thereof C04B24/243 takes precedence
• CPC Class Codes: C04B 28/14 containing calcium sulfate cements gypsum-paper plates E04C
• CPC Class Codes: C08K 2003/3045 Sulfates
• CPC Class Codes: C08K 3/30 Sulfur-, selenium- or tellurium-containing compounds
• CPC Class Codes: C08K 7/22 Expanded, porous or hollow particles
• CPC Class Codes: C08L 75/04 Polyurethanes
• CPC Class Codes: E04C 2/043 of plaster E04C2/049 takes precedence
• CPC Class Codes: Y10T 428/31996 Next to layer of metal salt [e.g., plasterboard, etc.]

Abstract

A novel wallboard composition is disclosed comprising a unique combination of synthetic binders selected for their ability to establish a strengthened permanent bond in the final dry state for use in a wallboard composition comprising primarily gypsum, and in a wallboard composition comprising an expanded mineral such as Perlite which largely reduces the amount of gypsum over current gypsum wallboard formulations, thus reducing the weight while maintaining the strength of the wallboard structure. In a preferred embodiment, the lightweight, strengthened wallboard of the present invention also comprises an optional covering veneer that is applied to the top ply of the face paper to provide increased strength, moisture resistance, and fire retardency, and the back paper top ply is treated to provide increased flexural strength. Additionally, this invention relates to the unique manufacturing process to produce the wallboard composition of the present invention in order to create a lightweight, strengthened, moisture resistant, and fire retardant wallboard used to cover walls and ceilings in construction applications. Still further, this invention relates to the apparatus for manufacturing the wallboard composition of the present invention, including a method and apparatus for economically converting a standard gypsum wallboard manufacturing facility into a facility for manufacturing wallboard of the present invention.

Claims

1. A slurry composition suitable for use in the manufacture of construction grade wallboard comprising:

expanded perlite present at about 0.5% up to about 47.5% by weight of the total wet weight of the slurry;

calcium sulfate;

a vinyl acetate emulsion comprising a homogeneous blend of suspended polyvinyl acetate particles in polyvinyl alcohol and water; and

a solution comprising a 10% to 25% solution of polyvinyl alcohol to water, said solution being present in said composition in an amount of approximately 0.1% to about 30% of said vinyl acetate emulsion.

2. The composition of claim 1, further comprising:

sodium trimetaphosphate present at about 0.01% up to about 10% by weight of the total wet weight of the slurry.

6. The composition of claim 1, said calcium sulfate being present in an amount not in excess of about 60% by weigh t of the total wet weight of the slurry.

3. A slurry composition suitable for use in the manufacture of construction grade wallboard comprising:

a dry powder mineral substrate selected from the group of minerals consisting of calcium sulfate, perlite, and combinations thereof;

a synthetic binder comprising a vinyl acetate emulsion, starch, and a boron source; and

a solution comprising a 10% to 25% solution of polyvinyl alcohol to water, said solution being present in said composition in an amount of approximately 0.1% to about 30% of said vinyl acetate emulsion.

4. The composition of claim 3, further comprising:

sodium trimetaphosphate present at about 0.01% up to about 10% by weight of the total wet weight of the slurry.

5. A method of manufacturing a construction grade wallboard product comprising the steps of:

forming a first mixture by adding a first solution comprising a 10% to 25% solution of polyvinyl alcohol to water to a vinyl acetate emulsion comprising a homogeneous blend of suspended polyvinyl acetate particles in polyvinyl alcohol and water, such that said first solution is present in said first mixture in an amount of approximately 0.1% to about 30% of said vinyl acetate emulsion;

forming a second mixture by adding a mineral selected from the group consisting of calcium sulfate, perlite, and combinations thereof, to said first mixture;

combining said second mixture with a suitable amount of water;

gradually preparing a slurry by mixing and stirring said second mixture and said water to form a slurry;

enveloping said slurry between two paper cover sheets to form a wet board; and

drying said wet board at a temperature in the range of 75°

C. to 325°

C.

7. A construction grade wallboard comprising:

a core formed from a slurry composition, said slurry composition further comprising;

expanded perlite present at about 0.5% up to about 47.5% by weight of the total wet weight of the slurry;

calcium sulfate;

a vinyl acetate emulsion comprising a homogeneous blend of suspended polyvinyl acetate particles in polyvinyl alcohol and water; and

a solution comprising a 10% to 25% solution of polyvinyl alcohol to water, said solution being present in said composition in an amount of approximately 0.1% to about 30% of said vinyl acetate emulsion; and

paper cover sheets sandwiching said core.

8. The construction grade wallboard of claim 7, said calcium sulfate being present in an amount not in excess of about 60% by weight of the total wet weight of the slurry.

9. The construction grade wallboard of claim 7, said slurry composition further comprising:

sodium trimetaphosphate present at about 0.01% up to about 10% by weight of the total wet weight of the slurry.

10. A construction grade wallboard comprising:

a core formed from a slurry composition, said slurry composition further comprising;

a dry powder mineral substrate selected from the group of minerals consisting of calcium sulfate, perlite, and combinations thereof;

a synthetic binder comprising a vinyl acetate emulsion, starch, and a boron source; and

a solution comprising a 10% to 25% solution of polyvinyl alcohol to water, said solution being present in said composition in an amount of approximately 0.1% to about 30% of said vinyl acetate emulsion; and

paper cover sheets sandwiching said core.

11. The construction grade wallboard of claim 10, said slurry composition further comprising:

sodium trimetaphosphate present at about 0.01% up to about 10% by weight of the total wet weight of the slurry.

12. A construction grade wallboard comprising:

a core formed from a slurry composition, said slurry composition further comprising;

a dry powder mineral substrate selected from the group of minerals consisting of calcium sulfite, perlite, and combinations thereof;

a vinyl acetate emulsion comprising a homogeneous blend of suspended polyvinyl acetate particles in polyvinyl alcohol and water; and

a solution comprising a 10% to 25% solution of polyvinyl alcohol to water, said solution being present in said composition in an amount of approximately 0.1% to about 30% of said vinyl acetate emulsion; and

paper cover sheets sandwiching said core.

13. The construction grade wallboard of claim 12, said slurry composition further comprising:

sodium trimetaphosphate present about 0.01% up to about 10% by weight of the total wet weight of the slurry.

14. The construction grade wallboard claim 12, wherein said vinyl acetate emulsion is present at about 0.00% to about 40% by weight of the total wet weight of the slurry.

15. The construction grade wallboard of claim 12, wherein said polyvinyl alcohol is present in said vinyl acetate emulsion at about 0.10% to about 30% of said vinyl acetate emulsion.

16. The construction grade wallboard of claim 12, wherein said polyvinyl alcohol is about 80% to about 100% hydrolyzed.