Treated mineral filler products, process for the preparation thereof and uses of same

Process for the preparation of a treated mineral filler product, characterised in that said process comprises the following steps:

• (a) providing at least one dry mineral filler;
• (b) providing at least one saturated C8 to C24 aliphatic carboxylic acid(s);
• (c) providing at least one di and/or trivalent cation salt of one or more saturated C8 to C24 aliphatic carboxylic acid;
• (d) contacting said mineral filler(s) of step (a), in one or more steps under heating, with:
• a. the “aliphatic carboxylic acid(s)” of step (b);
• b. the “aliphatic carboxylic acid salt(s)” of step (c);
• whereupon
• (e) a treatment layer comprising said aliphatic carboxylic acid(s) and said aliphatic carboxylic acid salt(s) is formed on the surface of said mineral filler(s) resulting in a treated mineral filler product;
• characterised in that:
• the weight ratio of all of said aliphatic carboxylic acid salt(s) provided in step (c):all of said aliphatic carboxylic acid(s) provided in step (b) is from 51:49 to 75:25;
• the total weight of all of said aliphatic carboxylic acid salt(s) and all of said aliphatic carboxylic acid(s) located on the surface of the mineral filler is at least 2.5 mg/m2 of the mineral filler provided in step (a);
• during step (d), the temperature is adjusted such that all of the aliphatic carboxylic acid(s) and aliphatic carboxylic acid salt(s) are molten.