DETAILED ACTION
Response to Amendment
This office action is in response to the Amendment filed on 1/26/2026. Claims 1-3, 5-8, 12, 15-20, 22-29, 32-33, 34-36, 47-48 and 50-51 are currently pending. Claims 34-36, 47,48, 50 and 51 were withdrawn without traverse in the reply filed on April 28,2025. Claims 1-3, 5-8, 12, 15-20, 22-29 and 32-33 are under examination.
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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 02/24/2026 has been entered.
Claim Analysis
Summary of Claim 1:
A method of making a lignocellulosic foam composition comprising
one or more lignocellulosic components, wherein the one or more lignocellulosic components comprise a micron-scale cellulose and/or cellulose nanofibrils (CNF) as a binding agent,
the method comprising the steps of:
(a)
creating a lignocellulosic slurry by combining the one or more of lignocellulosic components with a liquid component; and
(b)
exposing the lignocellulosic slurry to a first drying and foaming condition, wherein the first drying and foaming condition comprises microwave radiation, thereby creating a first lignocellulosic foam composition.
Claim Interpretation
Regarding claim 1, the language “exposing the lignocellulosic slurry to a first drying and foaming condition, wherein the first drying and foaming condition comprises microwave radiation,” is interpreted that the method requires the drying condition comprises microwave radiation and the foaming condition also comprises microwave radiation.
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.
Claims 1-3, 5-8, 12, 15-20 and 22-29 and 32-33 are rejected under 35 U.S.C. 103 as being unpatentable over Sun et al. (CN 106832520 A, full English Machine translation herewith) in view of Thole et al.(US PG Pub. 2018/0334777 A1).
Regarding claim 1, Sun et al. teach a method of making a biodegradable foaming composition for a flower seedling container (abstract), wherein the method comprises the steps of mixing municipal dewatered sludge, wood fibers, waste paper fibers and water to prepare a uniform slurry (abstract), thereby reading on the step (a); followed by pre-forming of the mixed slurry by compression molding. Then, the preformed material is foamed and dried using microwave radiation (claim 7), thereby reading on the step b.
Sun et al. further teach the wood fibers and paper fibers are crushed and pretreated to obtain smaller fibrous materials (which correspond to the lignocellulosic components comprising cellulose fibers); followed by mixing the fibrous material, sludge, water, crosslinking agent and lubricant to form a slurry (claim 7). Although Sun et al. are silent on the cellulose fibers as a binding agent, it is noted that its presence in the biodegradable foaming composition of Sun et al. would necessarily perform a binding function, because they are present in the composition.
Sun et al. are silent on the fiber size of the lignocellulosic components (micron-scale cellulose and /or cellulose nanofibrils).
However, Thole et al. teach a foamed composition [0040], wherein the untreated lignocellulose raw material (preferably wood [0015]) is subjected to communition and grinding processes to produce cellulose fibers at micron-scale dimensions, followed by the fibrillation of the secondary cell wall to form fibrils (cellulose nanofibrils). Thole et al. offers the motivation of using micron-scale cellulose and cellulose nanofibrils due to its ability to increase the particle surface area, lead to good gas retention capability during production and promote cohesion in the final solid foam [0033]. In light of these benefits, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to use the micron-scale cellulose and cellulose nanofibrils taught by Thole et al. on the method of making the foam composition of Sun et al., thereby arriving to the claimed invention.
Regarding claim 2, 3 and 5-7, Sun et al. teach one drying session using microwave equipment at a power of 350 W-600 W (claim 7) (See rejection of claim 1 above, which is incorporated by reference herein), which meet the limitation of “one or more drying sessions”, as required by the instant claim.
Regarding claim 8, Sun et al. teach that the density of the foamed material is between 0.3-0.8 g/cm3 (claim 10), which implies that the porosity of the foamed material is a variable property that can be controlled by variations in the microwave parameters (see Foods 2023 12,2497, Conclusion), as required by the instant claim.
Regarding claim 12, Sun et al. teach a method, wherein the lignocellulosic slurry is introduced into a mold, followed by a drying step of the lignocellulosic slurry (abstract, claim 7), as required by the instant claim.
Regarding claims 15-17, Sun et al. teach the foamed material comprises 50-84 parts municipal dewatered sludge or river silt having a moisture content of ≤95%, 5-20 parts wood fiber, 5-20 parts paper fiber, and 100-150 parts water. Sun et al. further teach that the wood fiber is industrial waste wood, wood fiber or wood chips where the large pieces of wood or wood fibers are shredded and then used (claims 1-4).
Sun et al. are silent on the nanocellulose fibers.
In the same field of endeavor (foamed materials), Thole et al. teach a composition, wherein the lignocellulosic material comprises cellulose fibers at micron-scale dimensions, and cellulose nanofibrils, as discussed in the rejection of claim 1. Thole et al. further teach a lignocellulosic slurry having a solids-water ratio of 1:2 to 1:20 [0020], which implies a concentration of cellulose fibers of 4.76 -33.3% (1/(1+2)=33%), that overlaps with the claimed range, thereby a prima facie case of obviousness being established. MPEP 2144.05. Accordingly, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to use the content of the micron-scale cellulose and nanocellulose fibers taught by Thole et al. as Thole et al. demonstrate this content of the cellulose fibers in a similar application with the expected result of increasing the particle surface area and promote cohesion in the final solid foam [0033], thereby arriving to the claimed invention.
Regarding claims 18-19, Sun et al. teach a method, wherein the lignocellulosic slurry further comprises the step of adding 3-30 parts crosslinking agent, 3-5 parts lubricant (claim 1, [0025]), which overlaps with the claimed range (1% to about 50 %), Further, in the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. (In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990).) It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have selected the overlapping portion of the range taught by Sun et al.
Regarding claim 20, Sun et al. teach a method, wherein the additives comprise polymer materials such as polyvinyl alcohol, polyethylene (claim 5), lubricants (claim 6) and wood derivative, metal particles and minerals that are usually present in municipal sludge, as required by the instant claim.
Regarding claim 22, Sun et al teach a method, wherein the slurry is dried to a moisture content of 8%-15% (claim 7), as required by the instant claim.
Regarding claim 23-24, Sun et al. teach drying conditions using a microwave equipment (claim 7), which reads on the drying condition comprising thermal energy. Sun et al. implies a first drying condition performed for 10-15 min using microwave radiation at a power of 350W-600W (Step 3 of claim 7) to create the foamed structure, wherein the high power boils the water content in the slurry, creating steam pressure that foams and expands the material (see Section 3.1 of Zubair et al.); followed by a second drying condition to remove the residual moisture until reaching 8-15% of moisture, as required by the instant claims.
Regarding claims 25-27, Sun et al. teach a first drying and foaming condition followed by a second drying condition until the desired moisture of 8-15% is reached (see rejection of claim 23). Therefore, it is obvious that the rate of liquid component removal (moisture removal) and the liquid content in the second drying condition is different and lower to that in the first, which leads to a second lignocellulosic composition with different properties compared with those of the first lignocellulosic composition, as required by the instant claims.
Regarding claims 28 and 32, Sun et al. are silent on the dried lignocellulosic foam composition with an outer layer of shell material.
However, Thole et al. teach the lignocellulosic foam composition can be veneered on both sides and used as lightweight structure panels and a lightweight middle layer in sandwich constructions [0040]. Thole et al. further teach the method further comprises the step of adding additives to the lignocellulosic composition, wherein said additives are in the form of one or more hydrophobizing agents, flame retardants, corona shielding agents and antimycotics (claim 12) and also teaches that the additives adjust desired properties in the foam (claim 11), [0040]), which implies the additives will be present in the outer layers. A person of ordinary skill in the art would have been motivated to combine the teachings of Sun et al. and Thole et al. because both references teach methods to produce lightweight, biodegradable foams derived from lignocellulosic slurries. It would have been reasonable to apply Thole’s lignocellulosic foam onto the foamed material of Sun et al. (core) to provide an outer shell with the predictable result of enhanced durability and mechanical properties, thereby arriving the claimed invention.
Regarding claims 29 and 33, Sun et al. teach the method comprising a first drying condition and a second drying condition as discussed in the rejection of claim 23. Sun et al. teach that the drying conditions ensure removal of desired moisture and that the drying is performed using microwave equipment or other heating and drying equipment (step 3-4 of claim 7). Sun et al. in view of Thole et al. teach a dried lignocellulosic foam composition with an outer layer as discussed in the rejection of claim 28.
Sun et al. in view of Thole et al. are silent on the third drying condition.
However, it would have been obvious to a person of ordinary skill on the art before the effective filing date of the claimed invention to add a third drying condition if residual moisture remained on the lignocellulosic foam composition after the incorporation of the outer layer. This additional step would be a predictable use of known methods to yield complete drying of both the core and the outer layer.
Response to Arguments
Applicant's arguments filed 1/26/2026 have been fully considered but they are not persuasive. In light of the amendment a 103 rejection is made over Sun et al. in view of Thole et al.
Regarding the rejection of claim 1 over Sun et al., Applicant states “ Not only does Sun not teach micron scale cellulose and /or cellulose nanofibrils, it does not teach that wood or paper fibers can be a binder and it includes required use of a crosslinking agent in order to affect binding of components. In response, Examiner acknowledges that the difference between the present invention and the prior art is that a crosslinking agent is not required in the present invention, however as written the claims do not expressly exclude a crosslinker. Attention is drawn to the rejection as set forth above, wherein the presence of the cellulose fibers in the composition of Sun et al. in view of Thole et al. would necessarily perform a binding function, because they are present in the composition and hydrogen bonding occurs between cellulose fibers when water is removed.
Examiner acknowledges that Sun et al. do not explicitly teach micro scale cellulose and/or cellulose nanofibrils. However, attention is drawn to the rejection as set forth above, wherein Thole et al. is used as a teaching reference regarding the importance of the size of the cellulose fibers in a foaming composition, and weather a crosslinking agent is present in the composition will not change that. Further, it is noted that Thole et al. teach the addition of crosslinking agents [0029] to improve the properties of the finished product [0029].
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to OLGA L. DONAHUE whose telephone number is (571)270-1152. The examiner can normally be reached M-F 8:00-5:00.
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, JOSEPH DEL SOLE can be reached on 571-272-1130. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
/OLGA LUCIA DONAHUE/Examiner, Art Unit 1763
/CATHERINE S BRANCH/Primary Examiner, Art Unit 1763