US 8546449

Here is a concise summary of US Patent 8546449:

US Patent 8546449: Methods and compositions for the generation of peracetic acid on site at the point-of-use

• Title: Methods and compositions for the generation of peracetic acid on site at the point-of-use
• Assignee: Enviro Tech Chemical Services Inc
• Inventors: Michael S. Harvey, Jonathan N. Howarth
• Filing Date: March 24, 2011
• Issue Date: October 1, 2013
• Abstract: The patent describes methods and compositions for generating peroxyacetic acid (PAA) sanitizer near its point-of-use. These methods involve combining a hydrogen peroxide-acetyl precursor solution (preferably containing triacetin) with water, mixing them, and then adding an aqueous solution of an alkali metal or earth alkali metal hydroxide. This process rapidly converts triacetin into peracetic acid, yielding solutions with high PAA levels. The patent also covers methods for preparing the hydrogen peroxide-acetyl precursor solution. Additionally, it discloses solid, freely-flowable peroxygen bleaching and stain removal compositions, comprising a liquid acetyl precursor, a water-soluble solid hydrogen peroxide source, and a water-soluble solid alkalinity source, for treating articles like fabrics, dentures, textiles, and food/beverage equipment.

Plain-Language Overview of Independent Claims:

• Claim 1 (Method for Continuous/Intermittent PAA Generation in Flowing Water): This claim describes a method to continuously or intermittently produce a peracetic acid (PAA) solution for disinfection or sanitization at the point-of-use. It involves:

  1. Providing flowing water.
  2. Providing a hydrogen peroxide-acetyl precursor solution, specifically with triacetin.
  3. Introducing and mixing the precursor solution into the flowing water, ensuring the precursor solution is 5.6% to 22.5% of the total volume, and the hydrogen peroxide-to-triacetin mole ratio is between 2.98:1 and 12.84:1.
  4. Providing an aqueous source of an alkali metal or earth alkali metal hydroxide.
  5. Introducing and mixing this hydroxide source into the mixture to form a reaction medium. The reaction medium's pH must be between 11.2 and 13.37, and the mole ratio of hydroxide-to-hydrogen peroxide-to-triacetin is between 4.2:3.8:1 and 4:4:1, allowing hydrogen peroxide and triacetin to react and form PAA.
  6. Continuously or intermittently producing the non-equilibrium PAA solution, which contains PAA, unreacted hydrogen peroxide, unreacted acetyl precursor, glycerine (from triacetin's perhydrolysis), the hydroxide source, and water. In this final solution, 40.9% to 85.7% of the triacetin is converted to PAA, 0.078% to 1.88% of hydrogen peroxide remains, and the PAA concentration is 1% to 7.1%.

• Claim 14 (Method for Continuous/Intermittent PAA Generation in a Container of Water): Similar to Claim 1, this claim outlines a method for continuously or intermittently generating a non-equilibrium PAA solution for disinfection or sanitization at the point-of-use. The key difference from Claim 1 is that instead of flowing water, it uses a container of water that is softened, deionized, or has sufficiently low hardness to prevent calcium salt precipitation upon alkali metal or earth alkali metal hydroxide addition. The subsequent steps regarding the introduction of the hydrogen peroxide-acetyl precursor solution (with triacetin), mixing ratios, pH, mole ratios of reactants, and the characteristics of the final PAA solution are substantially the same as those detailed in Claim 1.

• Claim 15 (Method of Preparing Hydrogen Peroxide-Acetyl Precursor Solution): This claim describes a method for preparing the hydrogen peroxide-acetyl precursor solution used in the generation methods. It involves:

  1. Introducing liquid triacetin (as the acetyl precursor) to an aqueous hydrogen peroxide solution, forming a hydrogen peroxide-triacetin solution.
  2. Allowing these components to mix to form the final hydrogen peroxide-acetyl precursor solution. This solution contains 23% to 40% hydrogen peroxide (from a 50% aqueous solution), 20% to 52% triacetin, water, and a trace amount of PAA that forms within the first day. The mole ratio of hydrogen peroxide-to-triacetin is between 2.98:1 and 12.84:1.

• Claim 16 (Solid Peroxygen Bleaching and Stain Removal Composition): This claim defines a freely-flowable, solid composition designed for laundry bleaching and stain removal. The composition comprises:

  1. A liquid acetyl precursor, specifically triacetin.
  2. A water-soluble solid source of hydrogen peroxide, specifically sodium percarbonate.
  3. A water-soluble solid source of alkalinity, which can be an alkali metal bicarbonate, carbonate, sesquicarbonate, borate, silicate, or hydroxide.
     The composition specifically contains 0.99% to 8.45% triacetin, 13% to 54% sodium percarbonate, and 24% to 44% of the solid alkalinity source. This composition is designed to produce peracetic acid when introduced to water.

Litigation Status:
US Patent 8546449 is involved in litigation. As of the current date, Google Patents indicates:

• A PTAB case, IPR2025-01472, was filed but not instituted procedurally [cite: "Family has litigation", "PTAB case IPR2025-01472 filed (Not Instituted - Procedural)"].
• A US case was filed in the Texas Western District Court (case number 1:24-cv-01313) [cite: "Family has litigation", "US case filed in Texas Western District Court"].
• There is also an indication of the first worldwide family litigation filed [cite: "Family has litigation", "First worldwide family litigation filed"].

No active cases specifically for US8546449 were found in the U.S. Court of Appeals for the Federal Circuit (CAFC) 2026 dockets based on the provided search results.