Composite sheet made from mechanically delaminated vermiculite

• US 5,139,615 A
• Filed: 12/28/1988
• Issued: 08/18/1992
• Est. Priority Date: 12/28/1988
• Status: Expired due to Fees

• Current Assignee: Hercules Incorporated (Ashland Global Holdings, Inc.)
• Original Assignee: Hercules Incorporated (Ashland Global Holdings, Inc.)
• Inventors: Dumas, David H., Conner, Herbert T.
• Primary Examiner(s): Chin, Peter
• Application Number:
  US07/290,739
• Time in Patent Office: 1,329 Days
• Field of Search: 162/145, 162/152, 162/181.6, 162/183, 162/168.2, 162/164.6, 162/168.3, 106/18.12, 106/415, 106/417, 106/482, 106/484, 428/363, 428/241, 428/324, 428/283
• US Class Current: 162/145
• CPC Class Codes: C04B 14/204 expanded
• CPC Class Codes: C04B 14/42 Glass
• CPC Class Codes: C04B 18/26 Wood, e.g. sawdust, wood shavings
• CPC Class Codes: C04B 24/121 Amines, polyamines
• CPC Class Codes: C04B 24/2652 Nitrogen containing polymers, e.g. polyacrylamides, polyacrylonitriles
• CPC Class Codes: C04B 30/02 containing fibrous materials
• CPC Class Codes: D21H 13/40 vitreous, e.g. mineral wool, glass fibres
• CPC Class Codes: D21H 13/44 Flakes, e.g. mica, vermiculite
• CPC Class Codes: D21H 17/375 Poly(meth)acrylamide
• CPC Class Codes: D21H 17/42 anionic
• CPC Class Codes: D21H 17/56 Polyamines; Polyimines; Polyester-imides
• CPC Class Codes: Y02W 30/91 Use of waste materials as fillers for mortars or concrete

Abstract

Disclosed is a process for making a composite sheet using papermaking techniques. The composite sheet comprises (1) 20% to 99%, based on the weight of solids, of vermiculite delaminated by mechanical shearing only, (2) 1% to 80%, based on the weight of solids, of at least one fibrous material and (3) 0.1% to 10%, based on the weight of the vermiculite, of at least one flocculating agent.

Claims

1. A composite sheet comprising (1) from about 20% to about 99%, based on the weight of solids, of vermiculite delaminated by mechanical shearing onlyand having a particle size of less than 200 microns, (2) from about 1% to about 80%, based on the weight of solids, of at least one fibrous material and (3) from about 0.1% to about 10%, based on the weight of the vermiculite, of a combination of a cationic and an anionic flocculant.

2. The material of claim 1 wherein the fibrous material is a combination of glass fibers and wood pulp.

3. The material of claim 1 wherein the flocculating agent is a combination of a cationic polyamine and an anionic acrylamide copolymer.

4. A process for preparing a composite sheet comprising the steps of:

(a) delaminating vermiculite by mechanical shearing only by subjecting an aqueous slurry of the ore to a shearing action until a dispersion containing vermiculite lamellae having dimensions less than 200 microns is produced,

(b) dispersing in water from about 20% to about 99% of the mechanically delaminated vermiculite and from about 1% to about 80%, based on the weight of solids, of at least one fibrous material,

(c) adding from about 0.1% to about 10%, based on the weight of the vermiculite, of at least one flocculating agent to flocculate the dispersion, and

(d) dewatering the flocculated dispersion to form a sheet.

5. The process of claim 4 which additionally comprises removing particles larger than 50 microns by physical means after step (a).

6. The process of claim 4 wherein the mechanical delamination step is carried out in the presence of a dispersant that does not swell the vermiculite.

7. The process of claim 4 wherein the dewatering step is carried out in a continuous manner to provide a composite sheet in roll form.

8. The process of claim 4 wherein the fibrous material is a combination of wood pulp and glass fibers.

9. The process of claim 4 wherein the flocculating agent is a combination of a cationic polyamine and an anionic acrylamide copolymer.

10. The composite sheet produced by the process of claim 4.

11. The composite sheet produced by the process of claim 5.

12. The composite sheet produced by the process of claim 6.

13. The composite sheet produced by the process of claim 7.

14. The composite sheet produced by the process of claim 8.

15. The composite sheet produced by the process of claim 9.