Process for delamination of layered silicates

Patent metadata

Field	Value
Publication number	US-11905419-B2
Application number	US-201916966929-A
Country	US
Kind code	B2
Filing date	Feb 4, 2019
Priority date	Feb 8, 2018
Publication date	Feb 20, 2024
Grant date	Feb 20, 2024

Abstract

A process for delamination of a layered silicate in an aqueous medium includes treating a synthetic or naturally occurring 2:1 clay mineral layered silicate with a delamination agent, and contacting the treated layered silicate with an aqueous medium. An amount of the delamination agent used to treat the layered silicate can be at least equal to the cation exchange capacity of the layered silicate. A delaminated layered silicate can be obtained from the process and provided in a dispersion, a composite, or a barrier.

First claim

The invention claimed is:

1. A process for delamination of a synthetic or naturally occurring 2:1 clay mineral layered silicate in an aqueous medium, the process comprising:
treating a synthetic or naturally occurring 2:1 clay mineral layered silicate with a delamination agent, the layered silicate having a layer charge L c greater than or equal to 0.25 and less than or equal to 1.0 and a charge equivalent area A s of 47.6 Å 2 /(2 L c ),
contacting the treated layered silicate with an aqueous medium,
wherein the delamination agent
i. is an ionic compound having exactly one positively charged atom, the positively charged atom being nitrogen or phosphorous;
ii. contains of functional groups covalently bonded to the positively charged atom and including any one or more of a hydroxyl group, an ether group, a sulfonic acid ester group, or a carboxylic acid ester group, of being a number from 1 to 10;
iii. comprises a total number of carbon atoms n c being from 2 to 20;
iv. has a ratio n c /(1+n f ) from 1 to 5; and
v. has a charge equivalent area Ad being from at least 0.90-fold to 2.00-fold 3 of the charge equivalent area of the layered silicate A s ; and wherein
the delamination agent is used to treat the layered silicate in an amount of at least equal to the cation exchange capacity of the layered silicate,
with the proviso that of is greater than or equal to 2, if L c is less than or equal to 0.6.

2. The process according to claim 1 , wherein the layered silicate is a smectite or vermiculite.

3. The process according to claim 1 , wherein the layered silicate is represented by general formula
[ M Lc/valency ] inter [M I m M II o ] octa [M III 4 ] tetra X 10 Y 2   (I)

wherein,
M represents metal cations of oxidation state 1 to 3;
M I represents metal cations of oxidation state 2 or 3;
M II represents metal cations of oxidation state 1 or 2;
M III represents atoms of oxidation state 4;
X represents di-anions;
Y represents mono-anions;
m is less than or equal to 2.0 for metal atoms M I of oxidation state 3;
m is less than or equal to 3.0 for metal atoms M I of oxidation state 2; and
o is less than or equal to 1.0.

4. The process according to claim 3 , wherein
M independently represent Li + , Na + , or Mg 2+ ;
M I independently represent Mg 2+ , Al 3+ , Fe 2+ , or Fe 3+ ;
M II independently represent Li + or Mg 2+ ;
M III is a tetravalent silicon cation;
X is O 2− ; and
Y independently represent OH − or F − .

5. The process according to claim 1 , wherein
the delamination agent
ii. contains 1 to 8 of the n f functional groups;
and/or
iii. comprises 2 to 15 of the total number of carbon atoms n c ; and/or
iv. has the ratio n c /(1+n f ) from 1 to 5.

6. The process according to claim 1 , wherein the delamination agent has 4 to 10 of the total number of carbon atoms n c .

7. The process according to claim 1 , wherein
the delamination agent
i. has exactly one positively charged nitrogen atom; and/or
ii. contains 1 to 6 of the of functional groups, the of functional groups including any one or more of a hydroxyl group, an ether group, and a carboxylic acid group; and/or
iii. comprises 3 to 10 of the total number of carbon atoms n c ; and/or
iv. has the ratio n c /(1+n f ) from 1 to 4.

8. The process according to claim 1 , wherein treating the layered silicate with the delamination agent includes treating the layered silicate with an aqueous solution of the delamination agent, wherein the concentration of the delamination agent in the aqueous solution is high enough to prevent delamination of the layered silicate while treating the layered silicate with the delamination agent.

9. The process according to claim 8 , wherein the concentration of the delamination agent in the aqueous solution is from 0.2 to 2 mol/L.

10. The process according to claim 8 , wherein the concentration of the layered silicate in the aqueous solution containing the delamination agent is in the range from 1 to 50 g/L.

11. The process according to claim 1 , wherein the aqueous medium has an ionic strength low enough to cause delamination of the treated layered silicate.

12. The process according to claim 1 , wherein when contacting the treated layered silicate with the aqueous medium, the aqueous medium includes water.

13. A delaminated layered silicate obtained according to the process according to claim 1 .

14. The process according to claim 5 , wherein the layer charge L c is greater than or equal to 0.3 and less than or equal to 0.95.

15. The process according to claim 8 , wherein the concentration of the delamination agent in the aqueous solution is in the range of 0.5 to 1.5 mol/L.

16. The process according to claim 8 , wherein the concentration of the layered silicate in the aqueous solution containing the delamination agent is in the range from 5 to 40 g/L.

17. The process according to claim 8 , wherein the concentration of the layered silicate in the aqueous solution containing the delamination agent is in the range from 10 to 30 g/L.

18. The process according to claim 1 , wherein when contacting the treated layered silicate with the aqueous medium, the aqueous medium includes purified water.

19. A delaminated layered silicate obtained according to the process according to claim 2 .

20. A delaminated layered silicate obtained according to the process according to claim 3 .

21. A delaminated layered silicate obtained according to the process according to claim 7 .

22. A dispersion of the delaminated layered silicate product of claim 13 in a polar solvent.

23. A composite material comprising a polymer and the delaminated layered silicate of claim 13 .

24. A barrier prepared by applying the dispersion of claim 22 to a substrate and then removing the solvent by drying.

Assignees

• Byk Chemie Gmbh

Inventors

• Daab Matthias
• Breu Josef
• Schiessling Hubert
• Kalo Hussein

Classifications

• C09C1/3063 Primary

  Treatment with low-molecular organic compounds · CPC title

• C01B33/405

  not containing aluminium · CPC title

• C01B33/425

  not containing aluminium · CPC title

• C08K3/346

  Clay · CPC title

• C09D1/02

  alkali metal silicates · CPC title