Obviousness

An analysis of obviousness under 35 U.S.C. § 103 requires identifying specific prior art references that, when combined, would render the claimed invention obvious to a person having ordinary skill in the art (PHOSITA) at the time of the invention. The motivation for such a combination must also be demonstrated.

Based on the provided patent text, the "Prior art keywords" are "weight", "dcoi", "composition", "wood", and "wax", and the "Prior art date" is 2021-08-05. However, no specific prior art documents (e.g., patent numbers, publication IDs, or journal articles) are listed within the "Prior Art section of this page" to serve as the basis for a detailed obviousness combination. Therefore, the following analysis is constructed hypothetically, assuming the existence of prior art documents consistent with the patent's own background statements and the provided keywords.

A PHOSITA in the field of wood preservation at the priority date of August 5, 2021, would likely possess knowledge regarding various wood treatment chemicals and methods, as well as common problems associated with their application, such as leaching and active ingredient loss.

Hypothetical Prior Art Landscape:

1. Primary Reference (Reference A - DCOI Wood Preservative): This hypothetical reference would disclose the use of 4,5-dichloro-2-octylisothiazol-3(2H)-one (DCOI) as a biocide in wood preservative compositions. The patent itself states that "DCOI dissolved in hydrocarbon solvents has also been proposed to treat wood for heavy duty applications" and "DCOI... has been used in wood preservative compositions for mold control and antibacterial activity." [cite: Original Patent Text] Such a reference would also likely mention effective concentrations for DCOI, potentially including or overlapping with the "at least 0.5% by weight" claimed in US12370716. [cite: Original Patent Text]

2. Secondary Reference (Reference B - Waxes/Resins for Wood Treatment): This hypothetical reference would disclose the use of waxes (e.g., paraffin wax, polyethylene wax) or solvent-borne polymeric resins (e.g., alkyd resins, hydrocarbon resins) in wood treatment compositions. These additives would be shown to serve known functions such as improving water repellency, enhancing dimensional stability, or, critically, improving the fixation and reducing the leaching or mobility of active biocidal ingredients within the wood substrate. The patent explicitly lists "wax" as a prior art keyword. [cite: Original Patent Text] The patent also defines "water repellent" as potentially comprising "a wax water repellent (e.g., paraffin wax, polyethylene wax, carnauba wax, slack wax), a silicone, or combinations thereof." [cite: Original Patent Text]

Obviousness Argument for Independent Claims 1, 10, and 15:

1. Wood Preservative Composition (Claim 1):
Claim 1 defines a wood preservative composition comprising at least 0.5% by weight DCOI and a retaining additive (solvent-borne polymeric resin, wax, or combination) with a DCOI:retaining additive weight ratio in a range of 1:5 to 5:1. [cite: Original Patent Text]

• Combination: A PHOSITA would be motivated to combine the DCOI wood preservative taught by Reference A with the retaining additives (waxes or solvent-borne polymeric resins) disclosed in Reference B.
• Motivation: The patent itself highlights that oil-borne preservatives like pentachlorophenol (Penta) were widely used but faced discontinuation due to classification as a persistent organic pollutant. [cite: Original Patent Text] This created a desire for "an alternative oil-borne preservative." [cite: Original Patent Text] While DCOI was known as a biocide for wood, a PHOSITA would recognize that biocides, especially those applied in solvent carriers, can be susceptible to leaching or migration over time, reducing their long-term effectiveness. Reference B would teach that waxes and polymeric resins are effective for enhancing water repellency and, crucially, for "binding the DCOI to the wood product, entrap[ping] the DCOI within the wood, physically fix[ing] the DCOI to the wood product, and/or otherwise inhibit[ing] movement of the DCOI in the wood product." [cite: Original Patent Text] Therefore, a PHOSITA would be motivated to combine DCOI with such a retaining additive to improve its retention, reduce leaching, and thereby enhance the longevity and efficacy of the DCOI-based wood preservative as an alternative to Penta. The specific concentration ranges for DCOI (at least 0.5% by weight) and the weight ratio of DCOI to retaining additive (1:5 to 5:1) would be considered routine optimization for a PHOSITA to achieve desirable preservative efficacy and cost-effectiveness.

2. Method of Treating Wood (Claim 10):
Claim 10 describes a method comprising contacting a wood substrate with the wood preservative composition (as defined in Claim 1) for a period suitable to inhibit fungal decay. [cite: Original Patent Text]

• Combination: Once the wood preservative composition itself is rendered obvious by the combination of Reference A and Reference B, the method of treating wood with this composition would also be obvious. Reference A (DCOI wood preservative) would teach the application of DCOI to wood for decay inhibition.
• Motivation: Standard wood treatment processes, such as dipping, soaking, spraying, brushing, vacuum, or pressure processes (including full-cell and empty-cell methods like Rueping and Lowry), are well-known in the art and defined by standards like those from the American Wood Protection Association (AWPA). [cite: Original Patent Text] A PHOSITA applying an improved DCOI-based composition with a retaining additive would routinely select and employ these established treatment methods to ensure adequate penetration and retention of the preservative system in the wood substrate.

3. Wood Product (Claim 15):
Claim 15 covers a wood product produced by treating a wood substrate with the wood preservative composition of Claim 1. [cite: Original Patent Text]

• Combination: The wood product would be the direct and expected result of performing the obvious method of treating a wood substrate with the obvious wood preservative composition.
• Motivation: A PHOSITA, motivated to create a more durable and longer-lasting DCOI-treated wood product with improved resistance to biocide loss, would foreseeably arrive at the claimed wood product. The desired characteristics of reduced DCOI leaching and dislodgeability, while presented as beneficial outcomes in the patent, would be the expected improvements sought by combining DCOI with known retaining additives. The various types of wood products (e.g., timber, utility poles, decks) and wood species mentioned in the patent are conventional substrates for wood preservation treatments. [cite: Original Patent Text]

In conclusion, without specific prior art documents, the combination of a hypothetical DCOI wood preservative (Reference A) with hypothetical disclosures of waxes or solvent-borne polymeric resins as retaining additives in wood treatment (Reference B) would render the claimed composition, method, and product obvious to a PHOSITA. The motivation would stem from the known need to enhance the fixation and reduce the loss of biocides in wood preservation, a problem that waxes and polymeric resins were conventionally known to address.