Pre-exfoliated layered material
Pre-exfoliated natural or synthetic, modified or unmodified layered materials are prepared by mixing layered materials with one or more plastics additives selected from the group consisting of ultraviolet light absorbers, hindered amine light stabilizers, antioxidants, colorants, flame retardants, antimicrobials and fatty acid additives and melt extruding the mixture. The layered materials are for example modified or unmodified layered silicate clays. The galleries of the layered materials in the mixtures are expanded to a level of less than full exfoliation. The melt extruded mixtures of layered materials and additives are highly useful to prepare polymer nanocomposites.
1. A pre-exfoliated layered material/additive composition consisting of (a) a pre-exfoliated natural or synthetic, modified or unmodified layered material, wherein a gallery of said layered material is between 3 nm and 20 nm; (b) a plastics additive which is a phosphite antioxidant; and (c) less than 20% by weight other components, based on the weight of said pre-exfoliated layered material/additive composition; and wherein the weight:weight ratio of said pre-exfoliated natural or synthetic, modified or unmodified layered material to said plastics additive is from about 10:90 to about 90:10.
2. The pre-exfoliated layered material/additive composition of claim 1 , wherein said pre-exfoliated natural or synthetic, modified or unmodified layered material is selected from the group consisting of montmorillonite, bentonite, beidellite, mica, hectorite, saponite, nontronite, sauconite, vermiculite, ledikite, magatite, kenyaite, stevensite, volkonskoite, hydrotalcite, illite, kaolinite, wollastonite, attapulgite, sepiolite, halloysite, talcum, silica and mixtures thereof.
3. The pre-exfoliated layered material/additive composition of claim 1 , wherein the weight:weight ratio of said pre-exfoliated natural or synthetic, modified or unmodified layered material to said plastics additive is from about 20:80 to about 80:20.
4. A pre-exfoliated layered material/additive composition consisting of (a) a pre-exfoliated natural or synthetic, modified or unmodified layered material; (b) a plastics additive which is a phosphite antioxidant; and (c) less than 20% by weight other components, based on the weight of said pre-exfoliated layered material/additive composition; and wherein the weight:weight ratio of said pre-exfoliated natural or synthetic, modified or unmodified layered material to said plastics additive is from about 10:90 to about 90:10.
5. The pre-exfoliated layered material/additive composition of claim 4 , wherein said pre-exfoliated natural or synthetic, modified or unmodified layered material is selected from the group consisting of montmorillonite, bentonite, beidellite, mica, hectorite, saponite, nontronite, sauconite, vermiculite, ledikite, magatite, kenyaite, stevensite, volkonskoite, hydrotalcite, illite, kaolinite, wollastonite, attapulgite, sepiolite, halloysite, talcum, silica and mixtures thereof.
6. The pre-exfoliated layered material/additive composition of claim 4 , wherein the weight:weight ratio of said pre-exfoliated natural or synthetic, modified or unmodified layered material to said plastics additive is from about 20:80 to about 80:20.