Non-asbestos millboard composition

• US 4,244,781 A
• Filed: 06/11/1979
• Issued: 01/13/1981
• Est. Priority Date: 06/11/1979
• Status: Expired due to Term

• Current Assignee: Berja Corporation
• Original Assignee: Nicolet Corporation
• Inventors: Heckman, Peter F.
• Primary Examiner(s): Cannon, James C.
• Application Number:
  US06/047,119
• Time in Patent Office: 582 Days
• Field of Search: 65/245, 65/253, 65/288, 65/348, 65/374 RM, 162/145, 162/159, 162/168 NA, 162/181 C, 162/181 D, 252/62, 29/132
• US Class Current: 162/145
• CPC Class Codes: C03B 35/181 Materials, coatings, loose coverings or sleeves thereof
• CPC Class Codes: C03B 35/185 having a discontinuous surface for contacting the sheets or ribbons other than cloth or fabric, e.g. having protrusions or depressions, spirally wound cable, projecting discs or tires
• CPC Class Codes: C04B 14/10 Clay sepiolite C04B14/042; grog C04B18/025
• CPC Class Codes: C04B 14/46 Rock wool ; Ceramic or silicate fibres C04B14/40, C04B14/42 take precedence
• CPC Class Codes: C04B 18/241 Paper, e.g. waste paper; Paper pulp
• CPC Class Codes: C04B 24/26 obtained by reactions only involving carbon-to-carbon unsaturated bonds C04B24/243 takes precedence
• CPC Class Codes: C04B 28/00 Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
• CPC Class Codes: C04B 28/26 Silicates of the alkali metals
• 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: Y02W 30/91 Use of waste materials as fillers for mortars or concrete

Abstract

A non-asbestos millboard refractory composition useful for the manufacture of lehr and glass tempering rolls and useful at temperatures above about 650° C. comprises on a dry weight basis 10-30 percent ceramic fiber, 0-10 percent organic fiber, 35-60 percent pyrophyllite and 20-35 percent inorganic binder. This composition is particularly useful in the manufacture of a non-asbestos millboard sheet which is formed by preparing an aqueous slurry of the components of this composition, adding flocculant and developing the flocculated composition into sheet form by placing the slurry on a rotating screened cylinder to effect formation and dewatering, transfering the dewatered and formed slurry to a synthetic felt and then to an accumulator roll, where layers of the slurry are accumulated upon one another to a desired thickness. The accumulated layers are then slit, removed and formed into flat sheets of desired dimensions for subsequent use.

Claims

1. A non-asbestos millboard refractory composition comprising on a dry weight basis 10-30 percent ceramic fiber, 0-10 percent organic fiber, 35-60 percent pyrophyllite and 20-35 percent inorganic binder.

2. A non-asbestos millboard refractory composition in accordance with claim 1 wherein the inorganic binder comprises 15-30 percent bentonite clay and 3-10 percent silicate.

3. A non-asbestos millboard refractory composition in accordance with claim 1 comprising on a dry weight basis 10-20 percent ceramic fiber, 2-5 percent organic fiber, 40-60 percent pyrophyllite, 15-30 percent bentonite clay and 3-10 percent silicate.

4. A non-asbestos millboard refractory composition in accordance with claim 1 wherein said silicate is sodium silicate.

5. A non-asbestos millboard refractory composition in accordance with claim 1 wherein said organic fiber comprises kraft fiber.

7. A lehr roll or glass tempering roll comprising substantially circular discs having the composition in accordance with claim 1 or 6 assembled, fitted and pressed onto a bar to provide a substantially cylindrical lehr roll or glass tempering roll.

6. A non-asbestos and asbestos-free refractory millboard composition consisting essentially on a dry weight basis of 10-30% by weight ceramic fiber, 0-10% by weight Kraft cellulosic fiber, 30-60% by weight pyrophyllite, 10-30% by weight bentonite clay and 5-15% by weight sodium silicate.

8. A non-asbestos millboard sheet comprising on a dry weight basis 10-30 percent ceramic fiber, 0-10 percent organic fiber, 35-60 percent pyrophyllite, 20-35 percent inorganic binder and 0 to 5.0 percent flocculant.

9. A non-asbestos millboard sheet in accordance with claim 8 wherein the inorganic binder comprises 15-30 percent bentonite clay and 3-10 percent silicate.

10. A non-asbestos millboard sheet in accordance with claim 8 comprising on a dry weight basis 10-20 percent ceramic fiber, 2-5 percent organic fiber, 40-60 percent pyrophyllite, 15-30 percent bentonite clay, 3-10 percent silicate and 0.1 to 1.0 percent flocculant.

11. A non-asbestos millboard sheet in accordance with claim 8 wherein said silicate is sodium silicate.

12. A non-asbestos millboard sheet in accordance with claim 8, wherein said organic fiber comprises kraft fiber.

13. A non-asbestos millboard sheet in accordance with claim 8 wherein said flocculant comprises a polyelectrolyte.

14. A non-asbestos millboard sheet in accordance with claim 13 wherein said polyelectrolyte comprises a polyacrylamide.

15. A method of producing a non-asbestos millboard sheet in accordance with claim 8 which comprises admixing said organic fiber and said ceramic fiber, adding said pyrophyllite and said inorganic binder in water to form an aqueous slurry, and flocculating and coagulating said slurry to form said millboard sheet from said flocced and coagulated slurry.

16. A method in accordance with claim 15 wherein said flocculating and coagulating of said slurry to form said millboard sheet comprises adding flocculant to said aqueous slurry.

17. A method of producing a non-asbestos millboard sheet in accordance with claim 16 which comprises admixing said organic fiber and said ceramic fiber, adding said pyrophyllite and said inorganic binder in the form of an aqueous solution in order to form an aqueous slurry, adjusting the water content of said slurry to about 1.0 to 5.0 percent and the temperature to about 20.0°

to 30.0°

C., adding a low molecular weight cationic polymer in an amount from about 0.05 to 5.0 percent, then adding a high molecular weight cationic polymer in an amount from about 0.05 to 0.5 percent to coagulate said slurry and forming said millboard sheet from said coagulated slurry.

18. A method in accordance with claim 15 wherein said flocculating and coagulating of said slurry to form said millboard sheet comprises adjusting the alkalinity of said slurry to a pH in the range pH 10-13 to coagulate said slurry and forming said millboard sheet from said coagulated slurry.