Fire resistant vermiculite composition board and method of manufacture

• US 4,043,862 A
• Filed: 07/21/1975
• Issued: 08/23/1977
• Est. Priority Date: 07/21/1975
• Status: Expired due to Term

• Current Assignee: Eucatex S. A. Industria E Gomercio
• Original Assignee: Eucatex S. A. Industria E Gomercio
• Inventors: Roberts, James R.
• Primary Examiner(s): Fisher, Richard V.
• Application Number:
  US05/597,451
• Time in Patent Office: 764 Days
• Field of Search: 162/181 C, 162/181 R, 162/181 D, 162/176, 162/149, 162/145, 162/135, 162/159, 162/183, 162/181 B, 162/187, 162/207, 162/217, 428/453, 428/454, 428/920, 428/332, 428/334
• US Class Current: 162/135
• CPC Class Codes: C04B 14/10 Clay sepiolite C04B14/042; grog C04B18/025
• CPC Class Codes: C04B 14/204 expanded
• CPC Class Codes: C04B 18/24 Vegetable refuse, e.g. rice husks, maize-ear refuse; Cellulosic materials, e.g. paper , cork
• CPC Class Codes: C04B 24/383 Cellulose or derivatives thereof
• CPC Class Codes: C04B 26/285 Cellulose or derivatives thereof C04B26/24 takes precedence
• CPC Class Codes: C04B 30/02 containing fibrous materials
• CPC Class Codes: C04B 40/02 Selection of the hardening environment
• CPC Class Codes: C04B 41/5076 with masses bonded by inorganic cements sulfur compositions C04B41/5097
• CPC Class Codes: Y02W 30/91 Use of waste materials as fillers for mortars or concrete
• CPC Class Codes: Y10S 428/92 Fire or heat protection feature
• CPC Class Codes: Y10T 428/263 Coating layer not in excess of 5 mils thick or equivalent

Abstract

A fire resistant vermiculite composition board comprises, in percent by weight, from 40 to 90% heat expanded vermiculite particles; from 5 to 20% ceramic clay particles; from 10 to 30% hydrated cellulosic gel having a TAPPI drainage time of at least 900 seconds; from 1 to 20% defiberized wood; and from 1 to 20% starch. The vermiculite is in an incompletely expanded condition of a degree predetermined to permit its further expansion upon subsequent exposure to heat. This results in a corresponding expansion of the composition board of which it is a component when the board is exposed to fire, preventing the formation of cracks and insuring continued fire protecting coverage of the area across which the board is applied.

Claims

1. Fire resistant vermiculite composition board comprising a felted, dried sheet comprising in dispersed admixture:

space="preserve" listing-type="tabular">______________________________________ % by weight ______________________________________ Heat-expanded vermiculite particles 40 to 90 Ceramic clay particles 5 to 20 Hydrated cellulosic gel having a TAPPI drainage time of at least 900 seconds 10 to 30. ______________________________________

2. Fire resistant vermiculite composition board comprising a felted, dried sheet comprising in dispersed admixture

View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12)

3. The composition board of claim 2 wherein the vermiculite is expanded to from 75 to 98% of its capacity for heat expansion.

4. The composition board of claim 2 wherein the vermiculite content is from 50 to 70% by weight.

5. The composition board of claim 2 wherein the hydrated cellulosic gel is characterized by a TAPPI drainage time of from 900 to 1,800 seconds.

6. The compositon board of claim 2 including from 1 to 20% by weight of wood in fibrous form.

7. The composition board of claim 2 including from 1 to 20% by weight of defiberized wood fibers having a TAPPI freeness of less than 750 C.S.F.

8. The composition board of claim 2 including from 1 to 20% by weight starch.

9. The composition board of claim 2 including from 1 to 20% by weight defiberized wood and from 1 to 20% by weight starch.

10. The composition board of claim 2 wherein at least one outer face of the board is covered with a coating of sodium silicate.

11. The composition board of claim 2 wherein at least one outer face of the composition board is coated uniformly with a substantially impervious coating of sodium silicate, the coating having a thickness of from 0.001 inch to 0.01 inch.

12. The composition board of claim 2 wherein the board has a moisture content of less than 1% by weight.

13. Fire resistant vermiculite composition board comprising a felted, dried sheet containing in dispersed admixture:

space="preserve" listing-type="tabular">______________________________________ % By Weight ______________________________________ Heat-expanded vermiculite particles 50 to 70 Ceramic clay particles 5 to 20 Hydrated cellulosic gel, having a TAPPI drainage time of at least 900 seconds 10 to 30 Wood in fibrous form 1 to 20 Starch 1 to 20 ______________________________________

the vermiculite being expanded to a degree of from 75 to 98% of its capacity for heat expansion, and at least one outer face of the board having substantially uniform, impervious coating of sodium silicate, the coating having a thickness of from 0.001 inch to 0.01 inch.

14. The process for the manufacture of fire resistant vermiculite composition board which comprises:

a. heating vermiculite to a temperature for a duration predetermined to partially expand the vermiculite to a degree of from 40 to 98% of its capacity for heat expansion,

b. forming an aqueous slurry of board-forming consistency comprising;

space="preserve" listing-type="tabular">______________________________________ % by weight ______________________________________ The partially expanded vermiculite of step "a" 40 to 90 Ceramic clay particles 5 to 20 Hydrated cellulosic gel having a TAPPI drainage time of at least 900 seconds 10 to 30 ______________________________________

c. vacuum forming the slurry into a wet sheet on a board-forming screen, and

d. drying the sheet.

15. The process of claim 14 including the step of heating the vermiculite under conditions predetermined to expand it to from 75 to 98% of its capacity for heat expansion.

16. The process of claim 14 including the step of adding to the slurry from 1 to 20 parts by weight starch and thereafter kiln drying the wet sheet in three temperature zones, the first being maintained at from 600°

to 700°

C., the second at from 450°

to 550°

C., and the third at from 400°

to 500°

C.

17. The process of claim 14 including the step of adding to the slurry from 1 to 20 parts by weight defiberized wood and thereby accellerating the drainage of the slurry on the board-forming screen.

18. The process of claim 14 including the step of coating at least one face of the dried sheet with a coating of sodium silicate.

19. The process of claim 14 wherein the sheet is dried to a moisture content of less than 1% by weight.