Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Information Disclosure Statement
Receipt is acknowledged of the Information Disclosure Statement filed 15 December 2023. The Examiner has considered the reference cited therein to the extent that each is a proper citation. Please see the attached USPTO Form.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1-9, 11-12 are rejected under 35 U.S.C. 103 as being unpatentable over Hwang (US-20180228671-A1) in view of Lee (US-20180178193-A1 located in Information Disclosure Statement) and Park (US-5750585-A).
With regard to claim 1, Hwang’s Examples 1 and 2 teaches a method of preparing a superabsorbent polymer (para [0090-0093]). The process involves formulating a monomer composition including acrylic acid (water-soluble acrylic acid-based monomer), NaOH (acrylic acid neutralizer), IRGACURE 819 (photopolymerization initiator), and polyethylene glycol diacrylate (internal crosslinking agent) (Example 1), followed by the addition of S1670 (Ryoto Sugar Ester S-1670, manufactured by Mitsubishi Chemical Food Corporation) (foam stabilizer) and sodium bicarbonate (foaming agent) to the mixture (Example 2).
Upon light irradiation, gelation occurs with concurrent polymerization and foaming. The resulting hydrogel is dried, pulverized, classified, and surface-crosslinked into a base polymer powder (paras. [0009], [0090-0093], Examples 1-2).
Hwang further notes the importance of foam stabilizer to optimize the foaming efficiency of the foaming agent, thereby forming a crosslinked polymer having an appropriate pore structure (para [0038]).
While Hwang shares overlapping components and method, it is limited to a single-stage foam structure and does not teach a two-stage foam or the inclusion of an additional foaming agent within the superabsorbent polymer. However, Hwang teaches the order of mixing the raw materials is not particularly limited, as well as, the method of adding the foaming agent is not particularly limited (para [0042-0043]).
In the same field of endeavor, Lee teaches a method of preparing a superabsorbent polymer, the method comprising the polymerizing or crosslinking a monomer composition. This composition consists of acrylic acid-based monomers having acidic groups which are at least partially neutralized, in the presence of a polymerization initiator, a first crosslinking agent, a low-temperature foaming agent, and a high-temperature foaming agent at 25 to 100° C. to yield a water-containing gel polymer. This process is finalized by drying, pulverizing, and surface crosslinking (para [0045-0049]). This approach shares overlapping components with both the claimed invention and reference and yields a two-stage foamed superabsorbent polymer, though it omits the use of a foam stabilizer.
Furthermore, Lee et al. teaches that the combination of a low-temperature foaming agent (e.g. sodium bicarbonate, para [0053]) with a high-temperature foaming agent (e.g. azodicarbonamide (ADCA), para [0054]) effectively controls the size and distribution of internal pores of the superabsorbent polymer. This methodology enhances the absorption rate under load without comprising gel strength (Abstract). Consequently, both foaming agents disclosed in Lee (low and high temperature) directly read on the corresponding first and second foaming agents listed in the current claims (claim 7).
In the same field of endeavor, Park teaches a hydrogel foam comprising a blowing agent (col 1, lines 53-55), noting that blowing agent can be selected based on their decomposition temperature, gas yield per unit weight, and the nature of their residual byproducts (col 2, lines 36-39). Generally, polymeric foams are generated by the expansion or vaporization of a dissolved blowing agent during or subsequent to polymerization (col 2, lines 40-44). For the gas bubbles to be effectively captured within the gel structure, they must be generated after the onset of gelation but prior to the formation of complete crosslinks (col 4-5, lines 65-67 and 1-2). Furthermore, a consistent rate of polymerization is desirable to optimize the time for blowing agents (e.g., NaHCO3) addition, thereby yielding a reproducible hydrogel foam matrix having with the desired physical characteristics (col 6, lines 32-35).
With regard to the additional foaming agent, it would have been obvious to a person of
ordinary skill in the art before the effective filling date of the claimed invention to divide the total quantity of foaming agent into multiple additions, or to introduce a secondary foaming prior to the completion of polymerization, as suggested by Park, in order to better synchronize gas generation with the increasing viscosity of the polymerizing mixture. A sequential foaming events enhance pore morphology and overall absorption performance, as suggested by Lee. In general, the transposition of process steps or the splitting of one step into two, where the processes are substantially identical or equivalent in terms of function, manner and result, was held to not patentably distinguish the processes, see Ex parte Rubin, 128 USPQ 159 (PO BdPatApp 1959). A person of ordinary skill in the art would have a reasonable expectation of success in achieving the claimed invention, as implementing an additional foaming step prior to polymerization represents the routine optimization of known process variables to achieve the recognized goal of improved pore and gas control. The modification of introducing a later portion of foaming agent would provide an additional foaming event and thereby predictably change and tailor pore structure while performing the same known functionality.
With regard to claims 2-3, Hwang teaches that a foam stabilizer is utilized at a concentration of about 0.0001 to 0.1% by weight based on the monomer mixture, to improve the foaming efficiency and form a crosslinked polymer with an appropriate pore structure (para [0038]). This disclosure reads on the claimed concentration range. While Hwang does not explicitly teach the concentration of the foam stabilizer concentration for each specific step or foaming process.
In the same field of endeavor, Lee teaches the pore area in a superabsorbent polymer can be tailored by controlling the weight ratio of the low-temperature foaming agent (e.g. sodium bicarbonate, para [0053]) and the high-temperature foaming agent (e.g. azodicarbonamide (ADCA), para [0054]) between 50:1 to 2:1 (para [0055]).
With regard to foam stabilizer concentration, Hwang offers the motivation to optimize the foam stabilizer in the superabsorbent polymer due to its ability to enhance the foaming efficiency of the foaming agent and improve the resulting pore structure (para [0038]). As such, the efficiency and concentration of the foaming agent will directly affect the polymer’s pore structure. Therefore, the amounts of foam stabilizer can be optimized to reach the desired efficiency of the foaming agent via a routine optimization. The case law has held that discovering an optimum value of a result effective variable involves only routine skill in the art. In re Boesch, 617 F.2d 272, 205 USPQ 215 (CCPA 1980). Thus, it would have been obvious to one having ordinary skill in the art before the effective filling date, to adjust the foam stabilizer in the superabsorbent of Hwang while in the weight ratio parameters of Lee to arrive at the claimed invention.
With regard to claim 4, Hwang teaches the incorporation of a foam stabilizer to enhance the efficiency of the foaming agent, yielding a crosslinked polymer with an appropriate pore structure (para [0038]), thereby reading on a surface-modified compound.
With regard to claim 5, Hwang teaches the use of polypropylene glycol as a foam stabilizer (para [0037]), which reads on a claimed foam stabilizer.
With regard to claims 6, 9, and 11, Hwang does not teach the temperature of polymerization or foaming.
In the same field of endeavor, Lee teaches the polymerization and crosslinking of a monomer composition at 25 to 100° C. to form a water-containing gel polymer (which overlaps the claimed temperature range). Lee notes that the prepared water-containing gel polymer has a low viscosity, resulting in pore sizes generated by the foaming process that exceed those generated by the high-temperature foaming agent (para [0052]), which reads on the claimed temperature range. Lee also notes the high temperature foaming agent is rather decomposed at higher temperatures (about 100° C., (para [0054]).
In the same field of endeavor, Park teaches when the foaming and polymerization temperature is maintained below 60° C., gas generation is driven primarily by the acid decomposition of carbonates (col 6, lines 15-18). Park emphasizes that maintaining a consistent rate of polymerization is crucial to optimize the timing of blowing agents (e.g. NaHCO3) addition, which yields a reproducible hydrogel foam matrix having the targeted characteristics (col 6, lines 32-35). Additionally, Park indicates that the percentage of open cell-foams increases when the foam is formed at temperatures below 65° C (col 7, lines 28-29), which overlaps the claimed temperature range.
With regard to the temperature, Lee and Hwang offers the motivation to optimize the temperature of foaming and polymerization, given the temperature’s direct impact on foaming agent decomposition, pore generation, and the overall structural characteristics of the superabsorbent polymer. As such, the temperature governs the polymer’s properties. Therefore, the temperature can be optimized to reach the desired retention of the foaming agent via a routine optimization. The case law has held that discovering an optimum value of a result effective variable involves only routine skill in the art. In re Boesch, 617 F.2d 272, 205 USPQ 215 (CCPA 1980). Thus, it would have been obvious to one having ordinary skill in the art before the effective filling date, to adjust the temperature in the superabsorbent of Hwang within the parameters of Hwang and Lee to arrive at the claimed invention.
With regard to claim 7, Hwang teaches the use of inorganic foaming agents, including sodium carbonate and potassium carbonate (para [0012]), which reads on the claimed foaming agent.
Lee. Teaches the use of low-temperature foaming agents such as, sodium bicarbonate, sodium carbonate, potassium carbonate (para [0053]), as well as, high-temperature foaming agents such as, azodicarbonamide, p,p′-oxybisbenzenesulfonylhydrazide (OBSH), p-toluenesulfonyl hydrazide (TSH) (para [0054]). These low and high temperature foaming agents correspond to the claimed first and second foaming agents.
Park teaches the use of sodium bicarbonate as the foaming agent (col 5, lines 48-49).
With regard to claim 8, While Hwang and Lee do not teach an additional monomer composition. Hwang teaches the order of mixing the raw materials is not particularly limited (para [0042]).
In the same field of endeavor, Park teaches hydrogel foams can be formulated from multiple monomer species to form a co-polymer based hydrogel foam (col 4, lines 7-10). Park further teaches that the size and number of the gas cells is determined by monomer concentration(col 1, lines 45-50), and overall foam density (col 7, lines 35-39) are governed by monomer concentration, monomer solution viscosity, crosslinking extent, surfactant type, and the volume of gas introduced.
With regard to the additional monomer, it would have been obvious to a person of
ordinary skill in the art before the effective filling date of the claimed invention to divide the total monomer amount into multiple additions or utilize a secondary monomer prior to the completion of polymerization to better gas cell generation and size. In general, the transposition of process steps or the splitting of one step into two, where the processes are substantially identical or equivalent in terms of function, manner and result, was held to not patentably distinguish the processes, see Ex parte Rubin, 128 USPQ 159 (PO BdPatApp 1959). A person of ordinary skill in the art would have a reasonable expectation of success in achieving the claimed invention, as introducing an additional monomer constitutes the optimization of a known process variable to achieve the established goal of improving gas cell generation and sizing.
With regard to claim 12, Hwang and Park do not teach the pore size.
In the same field of endeavor, Lee teaches the use of low- and high-temperature foaming agents to generate micropores (paras [0016-0017]). Lee further teaches that low-temperature foaming agent generates pores with a diameter of 100 to 400 μm (A), while high-temperature foaming agent generates pores with a diameter of 5 to 100 μm (B). Furthermore, Lee demonstrates a pore diameter ratio of A to B of pore 3:7 to 9:1, which reads on the claimed limitation as 70% falls within the range. Lee demonstrates that distributing both micropores and macropores within this specific ratio improves the absorption rate under load without compromising gel strength (para [0016-0017]). Lee further teaches the pore area ratio in the superabsorbent polymer can be tailored to by controlling a weight ratio of the low-temperature foaming agent and the high-temperature foaming agent as well (para [0055]).
With regard to pore size, Lee offers the motivation to optimize two foaming agents concentration to adjust/optimize pore size of the superabsorbent polymer due to its ability to affect the absorption rate under load may be improved while preventing reduction in gel strength (para [0038]). As such, the pore size of the superabsorbent polymer will affect the absorption rate of the superabsorbent polymer. Therefore, the type and concentration of foaming agent can be optimized to reach the desired pore characteristics via a routine optimization. The case law has held that discovering an optimum value of a result effective variable involves only routine skill in the art. In re Boesch, 617 F.2d 272, 205 USPQ 215 (CCPA 1980). Thus, it would have been obvious to one having ordinary skill in the art before the effective filling date, to adjust the foam agent parameters in the superabsorbent of Hwang in accordance with Lee’s teaching to arrive at the claimed invention.
Claim 10 is rejected under 35 U.S.C. 103 as being unpatentable over Hwang (US-20180228671-A1) in view of Lee (US-20180178193-A1 located in Information Disclosure Statement) and Park (US-5750585-A). as applied to claims 1-7, 9, and 11-12 above, and further in view of Nishimura (JP-2005036145-A)
The teachings of Hwang, Lee, Park are discussed above.
With regard to claim 10, Hwang and Lee do not explicitly teach the diameter of the bubbles present.
Park notes that the selection of a blowing agent is based on its decomposition temperature, the volume of gas generated per unit weight, and the nature of their residual decomposition products (col 2, lines 36-39). Generally, polymeric foams are generated by the expansion or vaporization of a dissolved blowing agent during or subsequent to polymerization (col 2, lines 40-44). For the gas bubbles to be effectively captured within the gel structure, they must be generated after the onset of gelation but prior to the formation of complete crosslinks (col 4-5, lines 65-67 and 1-2).
In the same field of endeavor, Nishimura teaches a resin composition comprising a polymerized, crosslinked polyacrylamide and a foaming agent (e.g. azodicarbonamide, para [0003], Abstract). Nishimura teaches that the foaming agent used should be high-quality and capable of forming various bubbles with superior foaming properties (para [0010]).
Furthermore, Nishimura teaches when the fine foaming agent is uniformly dispersed in the resin, bubbles across a wide range of diameters are formed, specifically nano-sized bubbles (e.g., 1 to 150 nm) (para [0061]), which overlaps the claimed bubble ranges.
As stated above, Hwang, Lee, and Park teach the use of additional foaming agents and foaming steps.
With regard to the bubble size, Park and Nishimura offers the motivation to optimize the foaming agent selected to generate a superior bubble size of the superabsorbent polymer due to its ability to affect gas generation volume, as suggested by Park, to achieve the teachings of Nishimura. The references collectively teach similar compositions (e.g., acrylic acid, foaming agents, and foams). Therefore, the type and concentration of foaming agent can be optimized to reach the desired retention of the bubble size via a routine optimization. The case law has held that discovering an optimum value of a result effective variable involves only routine skill in the art. In re Boesch, 617 F.2d 272, 205 USPQ 215 (CCPA 1980). Thus, it would have been obvious to one having ordinary skill in the art before the effective filling date, to optimize the foaming agent in the superabsorbent of Hwang to adapt the bubble size of Nishimura to arrive at the claimed invention.
Conclusion
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/A.A.W./Examiner, Art Unit 1761
/ANGELA C BROWN-PETTIGREW/Supervisory Patent Examiner, Art Unit 1761
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