Process of manufacturing thickeners and the use of thus produced thickeners in high-viscosity epoxy resin formulations

1. A process comprising mixing

at least one mixed mineral organoclay rheology additive, which comprises a quaternary alkyl-ammonium salt treated mineral clay mixture prepared by

i. forming an aqueous hormite clay slurry (a)

ii. forming an aqueous smectite clay slurry (b)

iii. combining the aqueous hormite clay slurry (a) with the aqueous smectite clay slurry (b) to form a combined clay slurry (c)

iv. treating the combined clay slurry (c) with one or more quaternary alkyl-ammonium salts

v. separating the thus produced quaternary alkyl-ammonium salt treated mineral clay mixture from the aqueous medium,

in which

the aqueous hormite clay slurry (a) being formed by

(i.1) dispersing a fraction of one or more hormite clays selected from the group of sepiolites and palygorskites in an aqueous medium to form a dispersion, and wherein the hormite clay fraction employed contains less than 3.0% by weight of Al 2 O 3 , less than 1.0% by weight of Fe 2 O 3 , and less than 3.5% by weight of the combination of Al 2 O 3 and Fe 2 O 3 ,

and

the aqueous smectite clay slurry (b) being formed by

(ii.1) dispersing a fraction of one or more smectite clays in an aqueous medium to form a dispersion,

and

in that the weight of the hormite clay content exceeds the weight of the smectite clay content in the combined clay slurry (c); and

subjecting the dispersions formed in (i.1) and (ii.1) to high speed fluid shear before carrying out step iii. and/or after having carried out step iii,

in a liquid composition comprising at least one epoxy resin.

2. The process according to claim 1 , the liquid composition further comprising a hardener comprising groups which react with epoxy groups.

3. The process according to claim 2 , the hardener being selected from the group consisting of diamines, polyamines, polyamides and cyclic carboxylic acid anhydrides and mixtures thereof.

4. A process for producing a mixed mineral organoclay rheology additive, which comprises a quaternary alkyl-ammonium salt treated mineral clay mixture, the process being characterized by:

i. forming an aqueous hormite clay slurry (a)

ii. forming an aqueous smectite clay slurry (b)

iii. combining the aqueous hormite clay slurry (a) with the aqueous smectite clay slurry (b) to form a combined clay slurry (c)

iv. treating the combined clay slurry (c) with one or more quaternary alkyl-ammonium salts, and

v. optionally separating the thus produced quaternary alkyl-ammonium salt treated mineral clay mixture from the aqueous medium,

in which

the aqueous hormite clay slurry (a) being formed by

(i.1) dispersing a fraction of one or more hormite clays selected from the group of sepiolites and palygorskites in an aqueous medium to form a dispersion, and wherein the hormite clay fraction employed contains less than 3.0% by weight of Al 2 O 3 , less than 1.0% by weight of Fe 2 O 3 , and less than 3.5% by weight of the combination of Al 2 O 3 and Fe 2 O 3 ,

and

the aqueous smectite clay slurry (b) being formed by

(ii.1) dispersing a fraction of one or more smectite clays in an aqueous medium to form a dispersion,

and

in that the weight of the hormite clay content exceeds the weight of the smectite clay content in the combined clay slurry (c); and

subjecting the dispersions formed in (i.1) and (ii.1) to high speed fluid shear before carrying out step iii. and/or after having carried out step iii.

5. The process according to claim 4 , wherein the weight of the fraction of one or more hormite clays (i) based on the total weight of the clays in the combined clay slurry is from 60 to 95 wt. %.

6. The process according to claim 4 , wherein the weight of the fraction of one or more smectite clays (ii) based on the total weight of the clays in the combined clay slurry is from 5 to 40 wt. %.

7. The process according to claim 4 , wherein the one or more smectite clays are selected from the group consisting of hectorites, montmorillonites, bentonites, beidelites, saponites, stevensites and mixtures thereof.

8. The process according to claim 7 , wherein the smectite clay is selected from the group consisting of hectorites, saponites and mixtures thereof.

9. The process according to claim 4 , wherein the quaternary alkyl-ammonium salt contains the same or different straight-chain or branched, saturated or unsaturated alkyl groups having 1 to 22 carbon atoms and the counter-ion moiety is selected from the group consisting of chloride, bromide, methylsulfate, nitrate, hydroxide, acetate, phosphate and mixtures thereof.

10. The process according to claim 9 , wherein the quaternary alkyl-ammonium salt is selected from the group consisting of dimethyl di(C 14-18 alkyl) ammonium chloride, methyl benzyl di(C 14-18 alkyl) ammonium chloride, dimethyl benzyl C 14-18 -alkyl ammonium chloride, dimethyl C 14-18 -alkyl 2-ethylhexyl ammonium methylsulfate and mixtures thereof.

11. The process according to claim 4 , wherein the mineral clay mixture is treated with about 5 to 80 mmol of the quaternary alkyl-ammonium salt per 100 g of clay in the combined clay slurry.

12. The process according to claim 4 , wherein subsequently to step (i.1) the aqueous slurry (a) and subsequently to step (ii.1) the aqueous slurry (b) are screened through an at least 100 mesh screen (U.S. standard mesh) to remove coarse particles.

13. The process according to claim 4 , wherein the aqueous slurry (a) and the aqueous slurry (b) are subjected to high speed fluid shear by passing the respective slurry or a mixture of the slurries through a narrow gap, across which a pressure differential is maintained.

14. A process comprising mixing the mixed mineral organoclay rheology additives as obtained by the process according to claim 4 in a composition as thickening agent.

15. The process according to claim 14 , wherein the mixed mineral organoclay rheology additives are used as thickening agents in a liquid composition.

16. The process according to claim 15 , wherein the liquid composition is a liquid organic composition.

17. The process according to claim 16 , wherein the liquid organic composition is selected from the group consisting of coating materials, sealants, adhesives, oil drilling fluids, gas drilling fluids, composite materials, moulding compounds and liquid organic compositions which contain besides the mixed mineral organoclay rheology additive only one or more organic solvents.

18. The process according to claim 15 , wherein the mixed mineral organoclay rheology additive is contained in an amount from 0.1 to 10 wt.-% based on the total weight of the liquid composition.

19. The process according to claim 1 , comprising mixing at least one mixed mineral organoclay rheology additive, which consists of a quaternary alkyl-ammonium salt treated mineral clay mixture prepared by

i. forming an aqueous hormite clay slurry (a)

ii. forming an aqueous smectite clay slurry (b)

iii. combining the aqueous hormite clay slurry (a) with the aqueous smectite clay slurry (b) to form a combined clay slurry (c)

iv. treating the combined clay slurry (c) with one or more quaternary alkyl-ammonium salts

v. separating the thus produced quaternary alkyl-ammonium salt treated mineral clay mixture from the aqueous medium,

in which

the aqueous hormite clay slurry (a) being formed by

(i.1) dispersing a fraction of one or more hormite clays selected from the group of sepiolites and palygorskites in an aqueous medium to form a dispersion, and wherein the hormite clay fraction employed contains less than 3.0% by weight of Al 2 O 3 , less than 1.0% by weight of Fe 2 O 3 , and less than 3.5% by weight of the combination of Al 2 O 3 and Fe 2 O 3 ,

and

the aqueous smectite clay slurry (b) being formed by

(ii.1) dispersing a fraction of one or more smectite clays in an aqueous medium to form a dispersion,

and

in that the weight of the hormite clay content exceeds the weight of the smectite clay content in the combined clay slurry (c); and

subjecting the dispersions formed in (i.1) and (ii.1) to high speed fluid shear before carrying out step iii. and/or after having carried out step iii,

in a liquid composition comprising at least one epoxy resin.

20. The process according to claim 4 for producing a mixed mineral organoclay rheology additive, which consists of a quaternary alkyl-ammonium salt treated mineral clay mixture, the process being characterized by:

i. forming an aqueous hormite clay slurry (a)

ii. forming an aqueous smectite clay slurry (b)

iii. combining the aqueous hormite clay slurry (a) with the aqueous smectite clay slurry (b) to form a combined clay slurry (c)

iv. treating the combined clay slurry (c) with one or more quaternary alkyl-ammonium salts, and

v. optionally separating the thus produced quaternary alkyl-ammonium salt treated mineral clay mixture from the aqueous medium,

in which

the aqueous hormite clay slurry (a) being formed by

(i.1) dispersing a fraction of one or more hormite clays selected from the group of sepiolites and palygorskites in an aqueous medium to form a dispersion, and wherein the hormite clay fraction employed contains less than 3.0% by weight of Al 2 O 3 , less than 1.0% by weight of Fe 2 O 3 , and less than 3.5% by weight of the combination of Al 2 O 3 and Fe 2 O 3 ,

and

the aqueous smectite clay slurry (b) being formed by

(ii.1) dispersing a fraction of one or more smectite clays in an aqueous medium to form a dispersion,

and

in that the weight of the hormite clay content exceeds the weight of the smectite clay content in the combined clay slurry (c); and

subjecting the dispersions formed in (i.1) and (ii.1) to high speed fluid shear before carrying out step iii. and/or after having carried out step iii.