Process for the preparation of surface treated mineral filler products and uses of same
The present invention relates to a process for preparing a surface treated mineral filler product, and to its preferred use in the field of plastic applications, and in particular polypropylene (PP)- or polyethylene (PE)-based breathable or extrusion coating film applications.
1. A treated mineral filler product obtained by a process comprising the steps of:
(a) providing at least one calcium carbonate-containing mineral filler;
(b) providing at least one aliphatic aldehyde having between 6 and 14 carbon atoms;
(c) contacting the at least one mineral filler of step (a), in one or more steps, with the at least one aliphatic aldehyde of step (b) such that the added amount of the at least one aliphatic aldehyde corresponds to a theoretical total weight of between 0.25 mg/m2 and 5 mg/m2 on the surface of the treated mineral filler product; and
(d) forming a treatment layer comprising the at least one aliphatic aldehyde and/or reaction products of the at least one aliphatic aldehyde on the surface of the at least one calcium carbonate-containing mineral filler of step (a) resulting in a treated mineral filler product having a volatile onset temperature of at least 220° C.
2. The product according to claim 1 , wherein the at least one calcium carbonate-containing mineral filler of step (a) is precipitated calcium carbonate (PCC) and/or natural ground calcium carbonate (GCC).
3. The product according to claim 1 , wherein the at least one calcium carbonate-containing mineral filler of step (a) is precipitated calcium carbonate (PCC) in one or more of aragonitic, vateritic and calcitic mineralogical crystal forms.
4. The product according to claim 1 , wherein the at least one calcium carbonate-containing mineral filler of step (a) is natural ground calcium carbonate (GCC) comprising ground marble, limestone, chalk, and/or dolomite.
5. The product according to claim 1 , wherein the at least one aliphatic aldehyde of step (b) is an aliphatic aldehyde having 6 to 12 carbon atoms.
6. The product according to claim 1 , wherein the at least one aliphatic aldehyde of step (b) is an aliphatic aldehyde having 6 to 9 carbon atoms.
7. The product according to claim 1 , wherein the at least one aliphatic aldehyde of step (b) is an aliphatic aldehyde having 8 or 9 carbon atoms.
8. The product according to claim 1 , wherein the at least one aliphatic aldehyde of step (b) is a saturated aliphatic aldehyde.
9. The product according to claim 1 , wherein the at least one aliphatic aldehyde of step (b) features an equivalent isolated viscosity of less than 500 mPa·s at 23° C.
10. The product according to claim 1 , wherein the at least one mineral filler provided in step (a) has a median particle size diameter d 50 in the range between 0.3 μm and 10 μm.
11. The product according to claim 1 , wherein the at least one mineral filler provided in step (a) has a specific surface area (BET) of between 1 m 2 /g and 10 m 2 /g as measured by the BET nitrogen method.
12. The product according to claim 1 , wherein the at least one mineral filler provided in step (a) has a specific surface area (BET) of between 3 m 2 /g and 8 m 2 /g as measured by the BET nitrogen method.
13. The product according to claim 1 , wherein the at least one mineral filler of step (a) has a moisture content of between 0.01 wt.-% and 1.0 wt.-%, based on the dry weight of the at least one mineral filler provided in step (a).
14. The product according to claim 1 , wherein step (c) further comprises contacting the at least one mineral filler of step (a) with at least one saturated aliphatic carboxylic acid having 6 to 28 carbon atoms and/or at least one cation salt of one or more saturated aliphatic carboxylic acids having 6 to 28 carbon atoms.
15. The product according to claim 1 , wherein step (c) further comprises contacting the at least one mineral filler of step (a) with a saturated aliphatic carboxylic acid selected from the group consisting of stearic acid, behenic acid, palmitic acid, isostearic acid, montanic acid, capric acid, lauric acid, myristic acid, and any mixtures thereof.
16. The product according to claim 1 , wherein step (c) further comprises contacting the at least one mineral filler of step (a) with a 2:1 to 1:2 mixture (by weight) of stearic acid and palmitic acid.
17. The product according to claim 1 , wherein step (c) further comprises contacting the at least one mineral filler of step (a) with at least one polysiloxane.
18. The product according to claim 1 , wherein step (c) further comprises contacting the at least one mineral filler of step (a) with polydimethylsiloxane.
19. The product according to claim 1 , wherein the treated mineral filler product obtained in step (d) has a volatile onset temperature of greater than or equal to 220° C.
20. The product according to claim 1 , wherein the treated mineral filler product obtained in step (d) has a volatile onset temperature of between 230° C. and 300° C.
21. The product according to claim 1 , wherein the treated mineral filler product obtained in step (d) has a moisture content of between 0.01 wt.-% and 0.15 wt.-%, based on the dry weight of the at least one mineral filler of step (d).
22. The product according to claim 1 , wherein the treated mineral filler product obtained in step (d) has a moisture content of between 0.02 wt.-% and 0.12 wt.-%, based on the dry weight of the at least one mineral filler of step (d).
23. The product according to claim 1 , wherein the treated mineral filler product obtained in step (d) has a moisture content of between 0.04 wt.-% and 0.08 wt.-%, based on the dry weight of the at least one mineral filler of step (d).
24. The product according to claim 1 , wherein the treated mineral filler product obtained in step (d) features a moisture pick up susceptibility such that its total surface moisture level is below 1.0 mg/g, of the dry treated mineral filler product after exposure to an atmosphere of 50% of relative humidity for 48 hours at a temperature of 23° C.
25. The product according to claim 1 , wherein the treated mineral filler product obtained in step (d) features a moisture pick up susceptibility such that its total surface moisture level is below 0.5 mg/g, of the dry treated mineral filler product after exposure to an atmosphere of 50% of relative humidity for 48 hours at a temperature of 23° C.
26. The product according to claim 1 , wherein the treated mineral filler product obtained in step (d) features a moisture pick up susceptibility such that its total surface moisture level is below 0.4 mg/g, of the dry treated mineral filler product after exposure to an atmosphere of 50% of relative humidity for 48 hours at a temperature of 23° C.
27. The product according to claim 1 , wherein the at least one aliphatic aldehyde having between 6 and 14 carbon atoms is heptanal.
28. The product according to claim 1 , wherein the at least one aliphatic aldehyde having between 6 and 14 carbon atoms is octanal.
29. The product according to claim 1 , wherein the at least one aliphatic aldehyde having between 6 and 14 carbon atoms is undecanal.
30. The product according to claim 1 , wherein the at least one aliphatic aldehyde having between 6 and 14 carbon atoms is dodecanal.