DETAILED ACTION
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 .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 09/30/2025 has been entered.
Status of the Claims
Pursuant to the amendment dated 09/30/2025, claims 20 and 23 have been cancelled. Claims 1-14, 16, and 17 were cancelled previously.
Claims 15, 18, 19, 21, 22, and 24-33 are pending and under current examination.
All rejections not reiterated have been withdrawn.
A terminal disclaimer is on file for US Patent 11,224,676.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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 15, 18, 19, 21, 22, 25-29, 32, and 33 are rejected under 35 U.S.C. 103 as being unpatentable over Areskoug et al. (US 2010/0286584; publication date: 11/11/2010; cited in the IDS filed 06/26/2023) in view of Park et al. (US 2009/0069736; publication date: 03/12/2009; of record) Haseyama et al. (US 2002/0193459; publication date: 12/19/2002; of record), Treat (WO2017/059430; publication date: 04/06/2017), and International Standard ISO 13322 (published 05/2014; of record).
With regard to claims 15, 32, and 33, Areskoug discloses a method of making a hydrophilic polyurethane foam comprising providing a water phase containing a surfactant and dispersed inert particles, providing an isocyanate terminated polyether having functionality of more than 2, and combining these to form a foam structure (abstract). The isocyanate terminated polyether may be Hypol™ hydrophilic prepolymer (0015) and has a cream time (i.e. it forms an emulsion) of 20-30 seconds (0019). After emulsion, the foam cures within about 400-800 seconds (0019).
Thus, Areskoug discloses a method of producing a hydrophilic polyurethane foam material comprising the steps of (i) preparing an aqueous mixture comprising at least one surfactant, (ii) mixing said aqueous mixture with a prepolymer composition to form an emulsion, and (iii) allowing the emulsion to cure, thereby producing said hydrophilic polyurethane foam material, wherein particles are added to said aqueous mixture in step (i) wherein the method does not comprise the use of any particles or structural units other than the nucleating particles.
The instant claims require the nucleating particles to be present in an amount of at least 5% by weight (instant claims 15 and 32) or at from 5 – 25% by weight (claim 33) of the prepolymer composition.
In the method disclosed by Areskoug, the carbon particles are used at 0.5 to 2 parts by weight and the prepolymer is used at 100 parts by weight, thus the percent of particle relative to prepolymer is 0.5 to 2 % by weight. This falls below the lower limit on amount of particles recited in the instant claims.
Areskoug discloses further that the disclosed method forms a foam to be used as a wound dressing for wounds producing moderate exudate (0040) and that the method creates a pore size of 30 – 1000 microns (Areskoug: claim 5).
Park, in the analogous art of polyurethane foams for wound dressings (title) discloses that for wounds with high levels of exudate, the dressing absorbs sufficient exudate when the pore size of the foam adjacent to the wound ranges from 10 – 80 microns (0001, 0004). Thus the relationship between pore size in a wound dressing and wound derived fluid uptake was recognized as of the instant effective filing date.
Haseyama, in the analogous art of polyurethane foams, discloses that fine powders can be used in the making of polyurethane foams as nucleating agents (0233) to decrease cell size of foams (0236) and can be used in amounts of from 0.5 to 20 parts by weight per 100 parts of a urethane-based polymer (0237).
Treat provides greater detail regarding the effect of a nucleating particle on foam formation in e.g. para 0085-0086: The size of cells within a polymer foam may be controlled by the bubble formation mechanism. For example, the cell size and distribution within a polymer foam can be controlled by a combination of the nucleation rate of bubbles and the growth rate of the bubbles. This nucleation and growth can be described by classic nucleation theory. Briefly, classic nucleation theory states that the formation of a bubble from a homogeneous polymer-gas solution is an energetically unfavorable process with an associated activation energy. The activation energy of the formation is inversely proportional to the cell nucleation rate. After a stable bubble forms, it then grows in size by depleting the surrounding solution of gas. In polymer foams, the activation energy associated with the bubble nucleation is the limiting factor in the number of bubbles created within a given volume. The activation energy associated with bubble nucleation can be reduced through heterogeneous nucleation, In this heterogeneous nucleation, the surface between a nucleating agent and the polymer may promote bubble formation by increasing the interfacial order of the gas bubble, increasing the interfacial order of the gas bubble may reduce the energetic barrier to nucleation by providing a favorable surface for nucleation. Such surfaces may have a surface energy that encourages wetting of the surface by the gas. In addition, these surfaces may have a high surface area in order to maximize the nucleation site density. Reducing the activation energy may provide a strategy for controlling the cell structure of polymer foams and controlling their mechanical properties. One of ordinary skill in the art would have had a thorough understanding of the mechanism via which nucleating particles affect bubble size during foam formation.
It would have been prima facie obvious to adjust the amount of nucleating agent in Areskoug’s method to adjust the pore size of the foam. The artisan of ordinary skill would have been motivated to reduce the pore size in order to be able to use the wound dressing for wounds producing above average amounts of exudate. The skilled artisan would have had reasonable expectation of success because the relationship between particulate nucleating agent and pore size of a polymer/polyurethane film was recognized and well-understood as of the filing date of the instant invention and Haseyama provides a working range in concentration as a starting point for optimization (see also MPEP 2144.05).
With regard to claims 15, 32, and 33, the particles in Areskoug’s method are inert particles of activated carbon (0010); however, other substances were known to serve the function of nucleating agents to adjust pore size of polyurethane foams as of the instant effective filing date: Haseyama discloses that carbon black, clay, and magnesium oxide were known nucleating agents at the time the instant invention was filed (0234). It would have been prima facie obvious to use any of these particles as the nucleating agent in Areskoug’s method because they were known to serve the same purpose as Areskoug’s activated carbon particles. See MPEP 2144.06.
With regard to claims 15, 32, and 33, the relevant disclosures of Areskoug, Park, and Haseyama are set forth above. These disclosures render obvious optimizing the pore size of a polyurethane foam wound dressing for wound exudate absorption by adding an inorganic nucleating agent in the range of 5-35% by weight of the prepolymer used to form the foam. None of these references disclose the claimed method of measuring the pore size of the polyurethane foam.
ISO 13322-1 was a well-known method of particle size analysis before the effective filing date of the invention.
It would have been prima facie obvious to use the above method to assess the pore size of the polyurethane foam during optimizing the effects of nucleating agents on pore size.
With regard to claims 18 and 19, as noted above, the particles are added to the aqueous mixture prior to combining with the prepolymer (limitation of instant claim 18). However, the examiner also points out that there are only a handful of times during the procedure during which the particles could be added, and trying any of these would have been obvious to one of ordinary skill (see MPEP 2143(I)(E)). Additionally, any order of combining ingredients is considered prima facie obvious (see MPEP 2144.04(IV)(C)).
With regard to claim 21, as noted above, the range for nucleating particle disclosed by Haseyama overlaps with the range in amount of nucleant required by the instant claims (see MPEP 2144.05).
With regard to claim 22, as noted above, Haseyama discloses that the particle size of the nucleating agent may be 50 microns or less. This range overlaps with the amount recited in the instant claims (see MPEP 2144.05).
With regard to claims 25-28, Areskoug discloses an example method using an isocyanate-capped polyether, and Park discloses that e.g. toluene diisocyanate and polyether polyols are suitable for the urethane-forming substances (0024) therefore one of ordinary skill would have recognized the species disclosed by Park as suitable for the genus disclosed by Areskoug.
With regard to claim 29, Park discloses including an antibiotic (i.e.antimicrobial) agent in the dressing (0022). The skilled artisan would have been motivated to do so in order to protect against infection and would have had reasonable expectation of success because such was routine in the art as of the instant effective filing date.
Claim 24 is rejected under 35 U.S.C. 103 as being unpatentable over Areskoug et al. (US 2010/0286584; publication date: 11/11/2010; cited in the IDS filed 06/26/2023), Park et al. (US 2009/069736; publication date: 03/12/2009; of record), Haseyama et al. (US 2002/0193459; publication date: 12/19/2002; of record), Treat (WO 2017/059430; publication date: 04/06/2017), and International Standard ISO 13322 (published 05/2014; of record) as applied to claims 15, 18, 19, 21, 22, 25-29, 32, and 33 above, and further in view of Tokiwa et al. (US 2003/0119928; publication date: 06/26/2023).
The relevant disclosures of Areskoug, Park, Haseyama, Treat, and International Standard ISO 13322 are set forth above. These disclosures render obvious optimizing the pore size of a polyurethane foam wound dressing for wound exudate absorption by adding an inorganic nucleating agent but do not disclose that the nucleating agent is alumina trihydrate.
Tokiwa discloses aluminum hydroxide was known as a nucleating agent for polymer foams as of the instant effective filing date (0032).
It would have been prima facie obvious to replace the nucleating agents rendered obvious by Areskoug, Park, and Haseyama with aluminum hydroxide (i.e. alumina trihydrate, CAS Registry No. 21645-51-2) because these substances were disclosed to serve the same purpose as of the instant effective filing date. See MPEP 2144.06.
Claims 30 and 31 are rejected under 35 U.S.C. 103 as being unpatentable over Areskoug et al. (US 2010/0286584; publication date: 11/11/2010; cited in the IDS filed 06/26/2023) in view of Park et al. (US 2009/069736; publication date: 03/12/2009) and Haseyama et al. (US 2002/0193459; publication date: 12/19/2002; of record), Treat (WO 2017/059430; publication date: 04/06/2017), and International Standard ISO 13322 (published 05/2014; of record) as applied to claims 15, 18, 19, 21, 22, 25-29, 32, and 33 above, and further in view of Okayama et al. (US4937273, Patented 26 June 1990; of record).
The relevant disclosures of Areskoug, Park, Haseyama, Treat, and International Standard ISO 13322 are set forth above. As noted above, Park discloses including an antibiotic (i.e. antimicrobial) agent in the dressing; however, does not specify a silver antimicrobial agent.
Okayama et al. is directed to a method for producing a flexible polyurethane foam with antimicrobial agent [Claim 1], where the polyurethane is prepared with polyols [Claim 6] and organic isocyanates [Claim 11]. Where the antimicrobial agent is silver ions, silver salts, silver nitrate [Col 3, lines 50, 60, limitation of claims 29-31] and maintains its antibacterial (i.e. antimicrobial) effect for a long period of time [Col 1, Lines 24-25].
Based on these teachings, it would have been prima facie obvious to one of ordinary skill in the art, at the time the invention was made, to combine the polyurethane foam of Areskoug/Park/Haseyama et al. with the antimicrobial agents of Okayama et al.. One of ordinary skill in the art would have been motivated to do so to prepare a flexible polyurethane foam with an embedded antimicrobial agent that maintains its antibacterial effect for a long period of time. A person of ordinary skill in the art would have had a reasonable expectation of success because this would merely require adding the antibacterial agents disclosed by Okayama to the foam during processing.
Response to Arguments
Applicant's arguments filed 09/30/2025 have been fully considered but they are not persuasive.
On page 7, Applicant points out that the instant claimed method produces a foam material with substantially homogeneous small cell sizes, such that the majority of the foam cells are 0.01 mm2 or less in cross-sectional size and asserts that such a foam is not disclosed or suggested in the cited prior art.
Insomuch as this may be an assertion of unexpected results, please refer to MPEP 716.02(b) which details the burden on Applicant to establish that results in a side-by-side comparison to the closest prior art are unexpected and significant. Specifically, Applicant must establish that differences in results are in fact unexpected and unobvious and are of both practical and statistical significance. Additionally, evidence of unexpected properties must be commensurate in scope with the claims.
In the instant case, no evidence establishing an unexpected improvement over the closest prior art has been made of record. The instant specification provides data showing that foams formed in the presence of 7% wt alumina trihydrate particles has smaller foam cell size and a greater absorbency than foams formed without any particles; however, the closest prior art contains a lower amount of a different type of particle (activated carbon) and it was well-known in the art that adding nucleating particles during manufacture decreases foam cell size. The prior art together teaches that foam cell size is correlated with absorbency, and that it can be decreased by including nucleating particles of various identity (carbon black, clay, and magnesium oxide in addition to the inert activated carbon particles disclosed by Areskoug) in amounts ranging from 0.5 to 20% wt. Thus, it would not have been surprising to the artisan of ordinary skill that including 7% nucleating particle in the instant method of forming a foam would create a more absorbent foam having smaller particle size than a foam formed without any nucleating particles at all.
On page 8, Applicant argues that Areskoug relates to activated carbon particles and nothing discloses or suggests exclusion of activated carbon particles nor does Areskoug disclose any alternative particles. Applicant points to Areskoug’s para 0010 as disclosing the activated carbon particles to be essential to Areskoug’s invention because they improve the maximum absorption and retention capacities of a hydrophilic polyurethane foam structure. Applicant points to data showing that absorption in Areskoug’s foams having activated carbon particles is 30% greater than foams formed without any particles at all, reproducing Table 1 on page 8 of the remarks.
Applicant appears to have interpreted Areskoug to teach that the nucleating particles must be activated carbon particles in order to provide benefit to the foam; however, the examiner respectfully disagrees with this interpretation. In view of each of the cited prior art references, Areskoug, Park, Treat, and Haseyama, one having ordinary skill would have understood that inert nucleating particles can decrease the size of foam cells, and that this is desirable to improve absorption of fluid into the foam. The examiner notes that Areskoug shows the presence of particles decreases the foam cell size; however, in view of the combination of references cited in the rejection, one having ordinary skill would have considered the prior art to teach that inert particles in general can provide the effect that is achieved in Areskoug with the particular particle, inert activated carbon. Areskoug does not state that inert activated carbon is the only substance that can be used as nucleating particles in their invention and the data only compare a foam formed with nucleating particles to one that lacks particles altogether. Similarly, the examiner considers para 0010 of Areskoug to teach that inert nucleating particles are essential to Areskoug’s invention; however, the combination of references establishes that one having ordinary skill would have understood several substances can provide the nucleating effect. In response to applicant's arguments against the references individually, one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986).
On page 9, Applicant argues that there is nothing in Areskoug that discloses or suggests the claimed distribution of average cross-sectional cell size with the combination of the cited prior art. Applicant cites Areskoug’s para 0013 as disclosing a pore size distribution between 30 and 1000 mm and points out Areskoug’s Fig 1 and Fig 1A, which Applicant characterizes as disclosing pore cell sizes of varying size. Applicant argues that nothing in the prior art makes it predictable that the exclusive use of the particles recited in the amended claims would result in the homogeneous pore size distribution recited in the amended claims.
The examiner notes that the present Application also does not establish that the exclusive use of the particles recited in the amended claims provides for the allegedly homogeneous pore size distribution recited in the amended claims. Data of record in the instant application establishes that including nucleating particles in the mixture prior to foam curing results in greater absorbency and smaller pore size relative to a foam manufactured without any nucleating particle; however, this effect was known in the art, cannot be attributed to the identity of the inert particle, nor does Areskoug disclose or suggest that it can. Again, in view of the combination of references, one having ordinary skill would have recognized that inert particles formed from different substances may act as nucleating particles in polyurethane foam manufacture. The examiner respectfully disagrees that the image of a foam in Areskoug’s figure 1 accurately depicts the size of their foam cells or could reasonably be used as a comparator to the instant foam cell size. The image is not a photograph but rather a pictorial representation. The examiner considers para 0013 to disclose a range that the cell size may suitably be in Areskoug’s foam, not that each foam formed by Areskoug’s method contains cells sized as small as 30 mm and as large as 1000 mm. Moreover, Areskoug reports pore size in units of length (mm) whereas the instant claims recite a unit of area for the dimensions of the pore, therefore a direct comparison of the numerical ranges is not appropriate. Regarding Applicant’s assertion that the instant claims recite a homogeneous pore size distribution, the examiner notes that the claims recite “said foam material have an average cross-sectional cell size of 0.01 mm2 or less” and this range has no lower limit and that this is an average size with no indication of the variability in foam cell size. Accordingly, the claims do not recite a limitation requiring homogeneous cell size distribution. In response to applicant's argument that the references fail to show certain features of the invention, it is noted that the features upon which applicant relies (i.e., that nothing in the prior art makes it predictable that the exclusive use of the particles recited in the amended claims would result in the homogeneous pore size distribution recited in the amended claims) are not recited in the rejected claim(s). Although the claims are interpreted in light of the specification, limitations from the specification are not read into the claims. See In re Van Geuns, 988 F.2d 1181, 26 USPQ2d 1057 (Fed. Cir. 1993).
On page 10, Applicant points out that Areskoug does not disclose the claimed range in nucleating particle size, but rather discloses an example having 1% wt of activated carbon particles.
In response, Applicant is reminded that “[d]isclosed examples and preferred embodiments do not constitute a teaching away from a broader disclosure or nonpreferred embodiments. In re Susi, 440 F.2d 442, 169 USPQ 423 (CCPA 1971).” (See MPEP 2123(II).) Moreover, In response to applicant's arguments against the references individually, one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986). In the instant case, the teaching to increase the percentage of nucleating particles relative to the prepolymer mix over the range taught by Areskoug is found in Park, Haseyama, and Treat.
On page 10, Applicant argues that there is no reasonable expectation of success with regards to obtaining a desired pore size with the combination of Areskoug and Park, and that Park does not disclose or suggest activated carbon particles however, Areskoug requires activated carbon particles. On page 10, Applicant argues that Haseyama does not disclose or suggest that the disclosed nucleating agents can be activated carbon particles such as those disclosed in Areskoug therefore one would have no motivation to combine Areskoug and Haseyama as Haseyama does not disclose or suggest the required activated carbon particles of Areskoug such that there is no link between the particles of Areskoug and those of Haseyama.
The obviousness conclusion is based upon the particles having been known for the same purpose as of the instant effective filing date, see MPEP 2144.06(II). There is no requirement for the evidence that inert active carbon particles (Areskoug) and carbon black, clay, and magnesium oxide (Haseyama) were each known nucleating agents at the time the instant invention was filed to have been in a single disclosure. Areskoug and Haseyama are properly combined under 35 USC 103 because they are in the same field of endeavor, namely formation of polyurethane foams. Additionally these references solve the same problem as the instant invention and each other, controlling foam opening size using inert particles, thus are properly combined under 35 USC 103 for this reason as well.
Conclusion
No claims are allowed.
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/KATHERINE PEEBLES/ Primary Examiner, Art Unit 1617