Fluid-resistant textile fabrics and methods
Coating compositions which include a blend of a fluorochemical and a particulate additive comprising a bimodal size distribution of inorganic nanoparticles are provided. The bimodal distribution of inorganic nanoparticles may include a quantity of smaller nanoparticles having an average size distribution of between about 1 to about 15 nm, and a quantity of larger nanoparticles having an average size distribution of between about 40 to about 500 nm. The smaller and larger nanoparticles may be present in a ratio of the smaller sized particles to the larger sized particles of at least 1.2, with the total amount of nanoparticles being present in an amount of between about 0.1 to about 10 wt. % based on total composition weight.
1. A coating composition to impart fluid-resistance to textile articles comprising:
a blend of a fluorochemical and a particulate additive comprising between about 0.1 to about 10 wt. %, based on total composition weight, of a bimodal size distribution of colloidal silica nanoparticles, wherein
the bimodal size distribution of colloidal silica nanoparticles includes (i) a quantity of smaller colloidal silica nanoparticles having a mean particle diameter of between about 1 nm to about 15 nm and (ii) a quantity of larger colloidal silica nanoparticles having a mean particle diameter of between about 40 nm to about 100 nm, and wherein
the smaller and larger colloidal silica nanoparticles are present in a ratio of the smaller colloidal silica nanoparticles to the larger colloidal silica nanoparticles of at least 1:2.
2. The coating formulation of claim 1 , wherein the bimodal size distribution of colloidal sillica nanoparticles is present in an amount of between about 1.0 to about 2.0 wt. % based on total composition weight.
3. The composition of claim 1 , wherein the fluorochemical comprises one or more organo-fluorine groups that contain a perfluorinated carbon chain having from 2 to about 16 carbon atoms.
4. The composition of claim 3 , wherein the perfluorinated carbon chain is a perfluorinated aliphatic group of the general formula C n F 2n+1 , where n is an integer of at least 1.
5. The composition of claim 4 , wherein n is from 4 to 8.
6. The compositions of claim 1 , wherein the smaller colloidal silica nanoparticles have a particle size of between about 10-20 nm, and the larger colloidal silica nanoparticles have a particle size of about 40-50 nm.
7. The compositions of claim 1 , wherein the smaller colloidal silica nanoparticles have a particle size of about 10 nm, and the larger colloidal silica nanoparticles have a particle size of about 40 nm.
8. A fluid-resistant textile article comprising a textile fabric substrate, and a coating composition according to claim 1 on the substrate.
9. A method of imparting fluid-resistance to a textile article comprising coating a textile fabric substrate with a coating composition according to claim 1 .