Method For Determining Stability Of A Liquid Fabric Softener Formulation

A method of preparing a stable liquid fabric softener formulation, comprising the steps of:

• (i) providing an effective amount of a water-insoluble quaternary ester or diester ammonium salt for desired softening effects and an effective amount of a water-soluble cationic antibacterial agent of formula (VIII) for desired antibacterial effects:
• wherein
• R2 and R3 are the same or different C8-C12 alkyl, or
• R2 is C12-16 alkyl, C8-18 alkylethoxy, C8-18 alkylphenoxyethoxy and R3 is benzyl, and
• X is a halide or is methosulfate;
• (ii) picking a desirable stability formula index value, wherein the desirable stability formula index value is 2.5 or greater than 2.5;
• (iii) determining an amount of a cationic polymer of formula (IX) needed to make a stable formulation according to following equation:
• amount of the cationic polymer equals or is greater than:
• [(Stability formula index*the amount of the cationic antibacterial agent of formula (VIII))−the amount of the quaternary ester or diester ammonium salt]/3
• wherein the cationic polymer of formula (IX) is:
• wherein
• R4 is H or CH3;
• Y is O or NH;
• Z is a linear alkyl chain of methylene units (CH2)x, where
• x is an integer from 2 to 18, a substituted alkyl chain from 2 to 18 carbons in length having at least one hydroxyl group anywhere along the chain length,
• a benzene ring wherein the Y and the N substituents attach to the benzene ring in a para relationship, or
• a branched alkyl chain having a total number of carbons atoms from 2 to 18 carbon atoms;
• R1, R2, and R3 are, independently, —CH3, —CH2—C6H5, —C2H5, -n-C6H13, -n-C10H21, -naphthalenyl, -benzofuranyl, or —CH2—C6H4—CH2—O—C6H4—CHO;
• X is an anion chosen from the group consisting of halides, sulfates, methosulfate, trifluoromethane sulfonate, tetrafluoroborate, carbonates, bicarbonates, and mixtures thereof, and
• n is between several hundred to about 100 million;
• and
• (iv) preparing the stable fabric softener formulation containing the quaternary ester or diester ammonium salt, the water-soluble cationic antibacterial agent of formula (VIII), and the cationic polymer in their respective amounts.

A method of imparting antibacterial and/or softening properties to a fabric comprising adding to the final rinse cycle of textile laundry a composition comprising a homogeneous dispersion of:

• a) from 0.5% to 20% by weight water-insoluble quaternary ester or diester ammonium salt;
• b) from 0.5% to 10% by weight of one or more water-soluble cationic antibacterial agents;
• c) from 0.05% to 5% by weight cationic acrylics polymer;
• and
• d) water.