Process for the preparation of a treated mineral filler product, the obtained mineral filler product and its uses

Abstract

The present invention relates to the domain of mineral filler treatment processes. The process for the preparation of a treated mineral filler product comprises the following steps: (a) treating at least one dry mineral filler with at least one Group II or Group III salt of a C8 to C24 aliphatic monocarboxylic acid to produce an intermediate mineral filler product; followed by (b) treating the intermediate mineral filler product of step (a) with at least one C8 to C24 aliphatic monocarboxylic acid to produce a treated mineral filler product. Applications in particular to prepare treated mineral filler products (such as Ca carbonate) to be used in plastic applications such as in polypropylene (PP)- or polyethylene (PE)-based breathable or extrusion coating film applications.

1 . A process for the preparation of a treated mineral filler product comprising the following sequential steps:
 (a) treating at least one dry mineral filler comprising calcium carbonate with at least one calcium and/or magnesium salt of a C12 to C18 aliphatic monocarboxylic acid under heat and mixing to obtain an intermediate mineral filler product comprising the at least one dry mineral filler coated with the at least one calcium and/or magnesium salt of a C12 to C18 aliphatic acid; and   (b) treating the intermediate mineral filler product obtained in step (a) with at least one C12 to C18 aliphatic monocarboxylic acid under reduced heat and mixing to produce a treated mineral filler product,   
       wherein the treated mineral filler product has a total volatile content of less than 0.25% by mass at a temperature range of 25 and 300° C. 
     
     
         2 . The process according to  claim 1 , wherein the treated mineral filler product has a total volatile content of less than 0.23% by mass at a temperature range of 25 and 300° C. 
     
     
         3 . The process according to  claim 1 , wherein the at least one dry mineral filler subjected to treatment in step (a) is precipitated calcium carbonate (PCC) and/or natural ground calcium carbonate (NGCC). 
     
     
         4 . The process according to  claim 1 , wherein the at least one dry mineral filler subjected to treatment in step (a) is precipitated calcium carbonate (PCC) of one or more of aragonitic, vateritic and calcitic mineralogical crystal forms. 
     
     
         5 . The process according to  claim 1 , wherein the at least one dry mineral filler subjected to treatment in step (a) is natural ground calcium carbonate (NGCC) prepared from marble, limestone, or chalk, and optionally comprising dolomite. 
     
     
         6 . The process according to  claim 1 , wherein the at least one dry mineral filler subjected to treatment in step (a) has a d 50  of 0.5 to 10 microns. 
     
     
         7 . The process according to  claim 1 , wherein the at least one dry mineral filler subjected to treatment in step (a) has a d 50  of 1.5 to 1.8 microns. 
     
     
         8 . The process according to  claim 1 , wherein the at least one dry mineral filler subjected to treatment in step (a) has less than 0.2% by weight of water relative to mineral filler weight. 
     
     
         9 . The process according to  claim 1 , wherein the at least one calcium and/or magnesium salt of a C12 to C18 aliphatic monocarboxylic acid introduced in step (a) is a calcium and/or magnesium salt of a C16 to C18 aliphatic carboxylic acid. 
     
     
         10 . The process according to  1 , wherein the at least one calcium and/or magnesium salt of a C12 to C18 aliphatic monocarboxylic acid introduced in step (a) is a calcium and/or magnesium salt of stearic, palmitic, myristic or lauric acid, or any mixture thereof. 
     
     
         11 . The process according to  1 , wherein the at least one calcium and/or magnesium salt of a C12 to C18 aliphatic monocarboxylic acid introduced in step (a) is a calcium and/or magnesium salt of stearic and/or palmitic acid. 
     
     
         12 . The process according to  claim 1 , wherein the at least one calcium and/or magnesium salt of a C12 to C18 aliphatic monocarboxylic acid introduced in step (a) is in the form of a dry powder. 
     
     
         13 . The process according to  claim 1 , wherein the at least one calcium and/or magnesium salt of a C12 to C18 aliphatic monocarboxylic acid introduced in step (a) has a viscosity of more than 100,000 mPas. 
     
     
         14 . The process according to  claim 1 , wherein the at least one calcium and/or magnesium salt of a C12 to C18 aliphatic monocarboxylic acid employed in step (a) has a viscosity of more than 1,000,000 mPas. 
     
     
         15 . The process according to  claim 1 , wherein the at least one calcium and/or magnesium salt of a C12 to C18 aliphatic monocarboxylic acid introduced in step (a) and the at least one C12 to C18 aliphatic carboxylic acid introduced in step (b) are not equivalent. 
     
     
         16 . The process according to  claim 1 , wherein the at least one C12 to C18 aliphatic carboxylic acid introduced in step (b) is stearic, palmitic, myristic or lauric acid, or any mixture thereof. 
     
     
         17 . The process according to  claim 1 , wherein the at least one C12 to C18 aliphatic carboxylic acid introduced in step (b) is stearic and/or palmitic acid. 
     
     
         18 . The process according to  claim 1 , wherein the at least one C12 to C18 aliphatic carboxylic acid introduced in step (b) is in the form of a melt. 
     
     
         19 . The process according to  claim 1 , wherein a total amount of the aliphatic carboxylic acid salt introduced in step (a) and the aliphatic carboxylic acid introduced in step (b) is 0.2 to 8 mg of total aliphatic carboxylic acid salt and aliphatic carboxylic acid per m 2  of mineral filler. 
     
     
         20 . The process according to  claim 1 , wherein a total amount of the aliphatic carboxylic acid salt introduced in step (a) and the aliphatic carboxylic acid introduced in step (b) is 0.6 to 5 mg of total aliphatic carboxylic acid salt and aliphatic carboxylic acid per m 2  of mineral filler. 
     
     
         21 . The process according to  claim 1 , wherein a total amount of the aliphatic carboxylic acid salt introduced in step (a) and the aliphatic carboxylic acid introduced in step (b) is 3 to 4 mg of total aliphatic carboxylic acid salt and aliphatic carboxylic acid per m 2  of mineral filler. 
     
     
         22 . The process according to  claim 1 , wherein the aliphatic carboxylic acid salt introduced in step (a) and the aliphatic carboxylic acid introduced in step (b) are selected so that their equivalent isolated mixture has a viscosity of between 5 and 60,000 mPas. 
     
     
         23 . The process according to  claim 1 , wherein the aliphatic carboxylic acid salt introduced in step (a) and the aliphatic carboxylic acid introduced in step (b) are selected so that their equivalent isolated mixture has a viscosity of between 5 and 400 mPas. 
     
     
         24 . The process according to  claim 1 , wherein the aliphatic carboxylic acid introduced in step (b) is a 1:1 stearic acid:palmitic acid mixture, and the aliphatic carboxylic acid salt introduced in step (a) is magnesium or calcium stearate. 
     
     
         25 . The process according to  claim 1 , wherein 0.4 by weight % of the aliphatic carboxylic acid, based on the weight of the mineral filler, is introduced in step (b), and 0.8 to 1.2 by weight % of the calcium and/or magnesium salt of an aliphatic carboxylic acid, based on the weight of the mineral filler, is introduced in step (a). 
     
     
         26 . The process according to  claim 1 , wherein 0.4 by weight % of the aliphatic carboxylic acid, based on the weight of the mineral filler, is introduced in step (b), and 0.8 by weight % of the calcium and/or magnesium salt of an aliphatic carboxylic acid, based on the weight of the mineral filler, is introduced in step (a). 
     
     
         27 . The process according to  claim 1 , wherein the weight ratio of the at least one C12 to C18 aliphatic monocarboxylic acid of step (b) to the least one calcium and/or magnesium salt of a C12 to C18 aliphatic monocarboxylic acid of step (a) is 1:1 to 1:10. 
     
     
         28 . The process according to  claim 1 , wherein the weight ratio of the at least one C12 to C18 aliphatic monocarboxylic acid of step (b) to the least one calcium and/or magnesium salt of a C12 to C18 aliphatic monocarboxylic acid of step (a) is 1:1.5 to 1:4. 
     
     
         29 . The process according to  claim 1 , wherein an additional treatment agent that does not correspond to a C12 to C18 aliphatic carboxylic acid, nor to a calcium and/or magnesium salt of a C12 to C18 aliphatic monocarboxylic acid, is introduced during the process. 
     
     
         30 . The process according to  claim 29 , wherein the additional treatment agent is a siloxane. 
     
     
         31 . The process according to  claim 30 , wherein the additional treatment agent is a polydimethylsiloxane (PDMS). 
     
     
         32 . The process according to  claim 30 , wherein the siloxane is dosed at 200 to 1000 ppm. 
     
     
         33 . The process according to  claim 30 , wherein the siloxane is dosed at 400 to 600 ppm. 
     
     
         34 . The process according to  claim 30 , wherein the siloxane is introduced following step (b).