Composite fiberboard and process of manufacture

• US 5,277,762 A
• Filed: 04/24/1992
• Issued: 01/11/1994
• Est. Priority Date: 04/26/1991
• Status: Expired due to Term

• Current Assignee: AWI Licensing Company
• Original Assignee: Armstrong World Industries Incorporated
• Inventors: Felegi, John Jr., Kehrer, Kenneth P., Wise, Edward E. Jr.
• Primary Examiner(s): Chin, Peter
• Application Number:
  US07/873,977
• Time in Patent Office: 627 Days
• Field of Search: 162/145, 162/152, 162/169, 162/175, 162/212, 162/216, 162/208, 162/181.6, 162/181.8
• US Class Current: 162/145
• CPC Class Codes: C04B 14/10 Clay sepiolite C04B14/042; grog C04B18/025
• CPC Class Codes: C04B 14/18 Perlite
• CPC Class Codes: C04B 14/38 Fibrous materials; Whiskers
• CPC Class Codes: C04B 18/241 Paper, e.g. waste paper; Paper pulp
• CPC Class Codes: C04B 2103/0065 Polymers characterised by their glass transition temperature (Tg)
• CPC Class Codes: C04B 2111/52 Sound-insulating materials
• CPC Class Codes: C04B 26/04 obtained by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: C04B 40/00 Processes, in general, for influencing or modifying the properties of mortars, concrete or artificial stone compositions, e.g. their setting or hardening ability active ingredients C04B22/00 - C04B24/00; hardening of a well-defined composition C04B26/00 - C04B28/00; making porous, cellular or lightening C04B38/00; mechanical aspects B28, e.g. conditioning the materials prior to shaping B28B17/02
• CPC Class Codes: C04B 40/0064 Processes of the Magnini or Hatscheck type
• CPC Class Codes: D21H 13/40 vitreous, e.g. mineral wool, glass fibres
• CPC Class Codes: D21H 17/68 siliceous, e.g. clays
• CPC Class Codes: Y02W 30/91 Use of waste materials as fillers for mortars or concrete

Abstract

A novel composite board of mineral wool, perlite, and cellulosic newsprint fibers for use as an acoustical tile is disclosed. The board displays a high porosity, a fine pore structure, a low density gradient through its thickness and an acceptable strength. The board is manufactured by a process that includes a flotation step prior to the final formation step.

Claims

1. A process for manufacturing a composite board product having a thickness of at least 0.5 inch and consisting essentially of up to 87% mineral wool, 5-75% perlite, 4-35% by weight cellulose fibers, 0-25% clay, and 2-15% by weight of a latex binder composition which comprises mixing the components with water to form an aqueous slurry;

feeding said slurry into an initial zone;

retaining said formed slurry in said zone without any further treatment for a time sufficient for turbulence to cease and for said cellulose fibers to disperse substantially uniformly throughout the thickness of said slurry; and

, immediately thereafter, transferring said slurry to the final forming zone wherein the formed material is drained of liquid and pressed into the shape of said product having a thickness of at least 0.5 inch; and

heating to solidify said product.

2. A process as in claim 1 wherein said initial zone is in the shape of a mold and said slurry is retained therein for at least 10 seconds.

3. A process as in claim 1 wherein said product contains up to 45% mineral wool and 40-75% perlite.

4. A process as in claim 1 wherein said slurry is retained in said initial zone for at least 20 seconds.

5. A composite board having a thickness of at least 0.5 inch consisting essentially of up to 87% by weight mineral wool, 5-85% by weight perlite, 0-25% by weight clay, 4-35% by weight cellulosic fibers, and 2-15% by weight of a binder composition comprising at least one thermoplastic polymer having a glass transition temperature of from 80°

C. to 115°

C., wherein the cellulose fibers in said board are substantially completely coated with said binder composition, said board displaying a density profile difference from front to back of less than about 0.05 pound per board foot and a noise resistance coefficient of at least 0.60.

6. The composite board of claim 5 comprising up to 45% mineral wool and 40-75% perlite.

7. A composite board of claim 5 having a thickness of 0.75-2.5 inches.

8. A process for manufacturing a composite board product having a thickness of at least 0.5 inch and consisting essentially of up to 87% mineral wool, 5-75% perlite, 4-35% by weight cellulose fibers, 0-25% clay, and 2-15% by weight of a binder composition which comprises mixing the components with water to form an aqueous slurry;

feeding said slurry into an initial zone;

retaining said formed slurry in said zone without any further treatment for a time sufficient for any turbulence to cease and for said cellulose fibers to disperse substantially uniformly throughout the thickness of said slurry; and

, immediately thereafter, transferring said slurry to the final forming zone wherein the formed material is drained of liquid and pressed into the shape of said product having a thickness of at least 0.5 inch; and

heating to solidify said product.

9. A composite board having a thickness of at least 0.5 inch consisting essentially of up to 87% by weight mineral wool, 5-85% by weight perlite, 0-25% by weight clay, 4-35% by weight of cellulosic fibers, and 2-15% by weight of a binder composition, said board displaying a density profile difference from front to back of less than about 0.05 pound per board foot and a noise resistance coefficient of at least 0.60.