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 .
DETAILED ACTION
This Office Action is responsive to Applicant’s Amendment and Remarks, filed June 23, 2026. The amendment, filed June 23, 2026, is acknowledged, wherein claims 1, 3 – 4, and 7 – 10 are amended.
Claims 1 – 16 are pending in this application and are currently examined.
Priority
This application is a national stage application of PCT/IB2022/050173, filed January 11, 2022, which claims benefit of foreign priority document IN202111001298, filed January 12, 2021.
Receipt is acknowledged of certified copies of papers required by 37 CFR 1.55.
Withdrawn Objections
The objection of claims 3 and 7 – 9 in the previous Office Action, dated February 23, 2026, is withdrawn in view of the amended claims 3 and 7 – 9.
Withdrawn Rejections
The rejection of claims 1 – 16 in the previous Office Action, dated February 23, 2026, under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention has been considered and is withdrawn in view of the amended claims 1, 4, and 10.
The rejection of claims 1 – 3 in the previous Office Action, dated February 23, 2026, under 35 U.S.C. 102(a)(1) as being anticipated by Xu has been considered and is withdrawn in view of the amended claim 1.
The rejection of claims 4 – 5 in the previous Office Action, dated February 23, 2026, under 35 U.S.C. 102(a)(1) as being anticipated by Xu has been considered and is withdrawn in view of the amended claim 4.
The rejection of claims 4 – 5, 9, and 12 – 15 in the previous Office Action, dated February 23, 2026, under 35 U.S.C. 103 as being unpatentable over Xu has been considered and is withdrawn in view of the amended claim 4.
The rejection of claims 6 and 10 in the previous Office Action, dated February 23, 2026, under 35 U.S.C. 103 as being unpatentable over Xu as applied to claims 4 – 5, 9, and 12 – 15 above, and further in view of Cadwalader has been considered and is withdrawn in view of the amended claim 4.
The rejection of claims 7 and 11 in the previous Office Action, dated February 23, 2026, under 35 U.S.C. 103 as being unpatentable over Xu as applied to claims 4 – 5, 9, and 12 – 15 above, and further in view of Wang et al. has been considered and is withdrawn in view of the amended claim 4.
The rejection of claim 8 in the previous Office Action, dated February 23, 2026, under 35 U.S.C. 103 as being unpatentable over Xu as applied to claims 4 – 5, 9, and 12 – 15 above, and further in view of Rodriguez-Chanfrau et al. has been considered and is withdrawn in view of the amended claim 4.
The rejection of claim 16 in the previous Office Action, dated February 23, 2026, under 35 U.S.C. 103 as being unpatentable over Xu as applied to claims 4 – 5, 9, and 12 – 15 above, and further in view of Anaya-Esparza et al. has been considered and is withdrawn in view of the amended claim 4.
The rejection of claims 1 – 5, 8, and 15 in the previous Office Action, dated February 23, 2026, on the ground of nonstatutory double patenting as being unpatentable over claims 1 and 4 of U.S. Patent No. 8952146B2 in view of Rodriguez-Chanfrau et al. has been considered and is withdrawn in view of the amended claims 1 and 4.
The following are maintained / new grounds of rejection necessitated by Applicant’s Amendment, filed June 23, 2026, wherein claims 1, 3 – 4, and 7 – 10 are amended.
Maintained Specification Objection
Applicant is reminded of the proper language and format for an abstract of the disclosure.
The abstract should be in narrative form and generally limited to a single paragraph on a separate sheet within the range of 50 to 150 words in length. The abstract should describe the disclosure sufficiently to assist readers in deciding whether there is a need for consulting the full patent text for details.
The language should be clear and concise and should not repeat information given in the title. It should avoid using phrases which can be implied, such as, “The disclosure concerns,” “The disclosure defined by this invention,” “The disclosure describes,” etc. In addition, the form and legal phraseology often used in patent claims, such as “means” and “said,” should be avoided.
The abstract is objected because the disclosure contains “said” in lines 1 and 6. Applicant is required to amend the abstract to avoid the language.
Responses to Applicant’s Remarks:
Applicant states that the abstract has been replaced with a new one in the format requested by the Office, and therefore requests withdrawal of the objection to the abstract. Applicant’s amendment to the abstract has been considered. However, the objection to the abstract is maintained because the amended abstract still contains the term “said”.
Maintained / New Claim Rejections - 35 USC § 112
The following is a quotation of the first paragraph of 35 U.S.C. 112(a):
(a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention.
The following is a quotation of the first paragraph of pre-AIA 35 U.S.C. 112:
The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor of carrying out his invention.
Claims 1 – 16 are rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, as failing to comply with the written description requirement. The claim(s) contains subject matter which was not described in the specification in such a way as to reasonably convey to one skilled in the relevant art that the inventor or a joint inventor, or for applications subject to pre-AIA 35 U.S.C. 112, the inventor(s), at the time the application was filed, had possession of the claimed invention.
Claim 1 is drawn to a high tenacity regenerated cellulosic fiber, which has a tenacity of at least 4.5 grams/denier and an elongation of at least 10%, measured in accordance with ASTM D 3822/D3822M-14 (2020) and claim 4 is drawn to a process for preparing a high tenacity cellulosic fiber having a tenacity of 4.5 grams/denier and elongation of at least 10% measured in accordance with ASTM D 3822/D3822M-14 (2020). The instant claims contain functional language by claiming the cellulosic fiber by what it does rather than what it is. See MPEP 2173.05(g). In the case of the instant claims, the cellulosic fiber is claimed based on the tenacity and elongation and not the structure or composition of the cellulosic fiber which would result in said tenacity and elongation.
The specification provides examples in which certain regenerated cellulosic fibers are produced and tested for tenacity and elongation. However, the examples only demonstrate a limited number of fibers meeting the claimed property limitations and do not identify structural features or a predictive process-property relationship that would allow one skilled in the art to recognized or obtain the full range of fibers encompassed by the claim. For example, the working examples provided in the specification disclose tenacity values within a limited range from 4.58 to 5.7 grams/denier under specific experimental conditions, including particular bacterial cellulose pre-treatment, degree of polymerization, pre-mix times, spinning temperatures, and blend ratios. These examples show that fibers prepared from bacterial cellulose pre-treated with particular pre-treatment agents, including hypochlorite as an oxidizing agent and sulphuric acid or hydrochloric acid as acid pre-treatment agents, under specific concentrations, treatment times, temperatures, and processing conditions, may achieve tenacity of least 4.5 grams/denier and elongation of at least 10%. However, the claims are not limited to those particular pre-treatment agents, concentrations, treatment times, temperature, or processing conditions. The concentration or percentage of the pre-treatment agent is significant because the extent of oxidation, acid hydrolysis, depolymerization, or other chemical modification of bacterial cellulose would be expected to depend on the identity and amount of pre-treatment agent, as well as treatment time and temperature. Such variables may affect the DP, cellulose chain structure, crystallinity, orientation, and other structural characteristics of the regenerated cellulosic fiber, which may affect the tenacity and elongation of the fiber. Thus, the limited working examples do not reasonably convey possession of the full scope of regenerated cellulosic fibers encompassed by claim 1, which broadly recites pre-treatment with an oxidizing agent, an acid, an alkali, or mixtures thereof, without limiting the concentration or treatment conditions required to obtain the claimed property profile. Further, the working examples do not report tenacity or elongation for fibers that are pre-treated with alkali, even though alkali pre-treatment is encompassed by claim 1. Thus, the specification provides no guidance establishing that such pre-treatment would yield fibers meeting the claimed tenacity and elongation limitations. Although Example 22 discloses a high shear mixing pre-treatment method that would also produce fibers meeting the functional limitations, high shear mixing is not an oxidizing agent, an acid, and alkali, or a mixture thereof as recited in amended claim 1. Therefore, Example 22 does not provide representative support for the claimed pre-treatment agent genus. Instead, Example 22 further illustrates that fibers meeting the claimed functional properties may be obtained under different process conditions, while the specification does not identify which critical pre-treatment parameters or structural characteristics are responsible for obtaining the claimed high tenacity and elongation profile across the full scope of the claims. The specification does not describe what critical parameters or structural characteristics of the cellulosic fiber contribute to the recited “high tenacity” property (page 20, Table 5). Because the claims broadly encompass multiple pre-treatment categories without reciting the particular concentrations or treatment conditions required to obtain the claimed property profile, the limited working examples do not reasonably convey possession of the full scope of the claimed regenerated cellulosic fiber.
The state of the art prior to the effective filing date of the claimed invention discloses that the tenacity of any fiber is driven by controllable conditions used in the manufacturing process. For example, Singh (Woodhead Publishing, 2017, Reference included with PTO-892) teaches that fiber tenacity and elongation at break are two important properties. The difference in the fiber tenacity can generally be attributed to several factors that are the degree of polymerization, the strength of bonding between adjacent polymer chains, the degree of orientation in the direction of fiber axis and the extent of crystallinity. Fibers that possess higher crystallinity, higher chain orientation and strong interchain bonding will generally exhibit lower values of elongation at break (page 20, para. 3). Based on Singh, one of ordinary skill in the art would reasonably conclude that multiple conditions are affecting the tenacity of the fiber.
It is not evident by the disclosure or the prior art that Applicant was in possession of a representative number of species of fibers, which have a high tenacity and the tenacity of at least 4.5 as claimed in the instant claim. Furthermore, as discussed above, the specification does not provide an adequate number of examples and does not identify the structural features that contribute to the tenacity of the fiber. Therefore, the instant claims was determined not to meet the written description requirement. Dependent claims 2 – 3 and 5 – 16 are rejected because these claims are either referring to the high tenacity regenerated cellulosic fiber or the manufacture of it.
Responses to Applicant’s Remarks:
Applicant argues that the written description requirement is satisfied because the specification describes pre-treatment of bacterial cellulose, suitable pre-treatment agents, the relevant DP ranges, and working examples demonstrating fibers with the claimed property profile. Applicant further argues that the amended claims are commensurate with the disclosed invention because the claims have been narrowed to recite the disclosed pre-treatment agents, the disclosed DP range, the process sequence, and the property measurements. Applicant’s arguments have been considered but are not persuasive. Although the specification discloses certain working examples of regenerated cellulosic fibers having tenacity and elongation values within the claimed ranges, the claims remain broader than the examples and are still defined, in part, by the functional result that the fiber has a tenacity of at least 4.5 grams/denier and an elongation of at least 10%. The specification does not identify sufficient structural features or a predictive process-property relationship that would reasonably convey to one of ordinary skill in the art that Applicant possesses the full scope of regenerated cellulosic fibers encompassed by the claims. The claims are not limited to the particular pre-treatment conditions, DP values, pre-mix times, spinning temperature, blend ratios, or other process variables used in the working examples. The state of the prior art further supports this point because fiber tenacity and elongation are affected by multiple interrelated process and structural variables, including degree of polymerization, bonding between adjacent polymer chains, molecular orientation along the fiber axis, and crystallinity, such that the claimed tenacity and elongation are not predictably obtained from the limited number of working examples. Because fiber tenacity and elongation are affected by multiple process and structural variables, disclosure of a limited number of examples does not reasonably describe the full genus of fibers defined by the claimed functional property requirements.
Applicant argues that the specification explains that reducing and controlling the DP of bacterial cellulose before dissolution improves dissolution behavior and enables production of regenerated cellulose fibers having high tenacity and elongation. Applicant further argues that the amended claims recite pre-treated bacterial cellulose having a DP of 450 – 1500 and therefore align with the technical teaching of the specification. Applicant’s arguments have been considered but are not sufficient to overcome the rejection. The recitation of a DP range of 450 – 1500 narrows the claims, but it does not by itself establish possession of all regenerated cellulosic fibers within the scope of the claims that also exhibit the required tenacity and elongation values. The specification indicates that DP can affect dissolution and fiber properties, but the disclosure does not establish that any bacterial cellulose pre-treated with any recited pre-treatment agent to any DP within the broad range of 450 – 1500 would predictably produce regenerated fibers having tenacity of at least 4.5 grams/denier and elongation of at least 10%. The claimed property profile depends on multiple variable beyond DP alone, including the particular pre-treatment chemistry, treatment conditions, dissolution conditions, spinning conditions, regeneration conditions, and blend composition. Therefore, the amended DP limitation does not cure the lack of written description for the full scope of fibers claimed by functional property limitations.
Applicant argues that the claims are supported because the specification discloses suitable pre-treatment agents, including oxidizing agents, acids, alkalis, and mixtures thereof, and provides examples showing that pre-treated bacterial cellulose can produce fibers having the claimed tenacity and elongation. Applicant’s arguments have been considered but are not persuasive. The examples relied upon by Applicant demonstrate only limited species and limited process conditions. The specification does not provide an adequate number of representative examples across the full scope of the claimed pre-treatment agents, For example, the rejection notes that the working examples show fibers pre-treated with hypochlorite or acids, such as sulfuric acid and hydrochloric acid, but do not report tenacity or elongation data for fibers prepared from alkali pre-treated bacterial cellulose. The claims, however, encompass pre-treatment with oxidizing agents, acids, alkalis, and mixtures thereof. Thus, the disclosure does not show possession of the full scope of the claimed genus, particularly where the claimed fiber properties are functional limitations and the specification does not provide guidance establishing which combinations of pre-treatment agents and processing conditions will reliably yield fibers meeting both the tenacity and elongation requirements.
Applicant argues that the claims need not recite every structural detail because the disclosure reasonably supports the claimed genus and the relevant process variables are described. Applicant’s argument has been considered but is not persuasive. The issue is not whether every structural or process detail must be recited in the claims. Instead, the issue is whether the originally filed disclosure reasonably conveys possession of the full scope of the claimed fibers, which are defined by the functional property requirements of tenacity and elongation. The specification does not identify structural characteristics of the regenerated cellulosic fiber, or a sufficiently predictive relationship between the disclosed process variables and the claimed fiber properties, that would allow one of ordinary skill in the art to recognize the full scope of fibers encompassed by the claims. The prior art evidence cited in the rejection further supports that fiber tenacity and elongation are affected by several variables, including degree of polymerization, bonding between polymer chains, chain orientation, and crystallinity. Therefore, the limited working examples and general process disclosure do not reasonably describe the full scope of the presently claimed fibers.
Applicant argues that the present amendments narrow the claims to the disclosure pre-treatment types and disclosed DP range, thereby aligning the claims with the exemplary embodiments and overcoming the written description concern. Applicant’s arguments have been considered but are not persuasive. The amendments narrow certain aspects of the claims, but the claims still encompass a broad genus of regenerated cellulosic fibers prepared from bacterial cellulose pre-treated by different classes of agents, including oxidizing agents, acids, alkalis, and mixtures thereof, over a DP range of 450 – 1500, and further require the functional properties of tenacity of at least 4.5 grams/denier and elongation of at least 10%. The specification does not provide representative species or sufficient identifying characteristics across the full scope of genus. Accordingly, the amendments do not overcome the written description deficiency, and the rejection under 35 U.S.C. 112(a) is maintained.
Claims 1 – 16 are rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, as failing to comply with the written description requirement. The claim(s) contains subject matter which was not described in the specification in such a way as to reasonably convey to one skilled in the relevant art that the inventor or a joint inventor, or for applications subject to pre-AIA 35 U.S.C. 112, the inventor(s), at the time the application was filed, had possession of the claimed invention.
Claims 1 and 4 have been amended to recite that the tenacity and elongation are measured in accordance with “ASTM D 3822/D3822M-14 (2020)”. However, the originally filed specification describes measurement in accordance with ASTM D 3822 only. The specification does not disclose the specific standard ASTM D 3822/D3822M-14 (2020). Further, although the working examples report tenacity and elongation values, the specification does not describe the actual measurement steps used in the examples in sufficient detail to show that the measurement process used in the examples corresponds to ASTM D 3822/D3822M-14 (2020). For example, the specification does not identify the specimen preparation, testing condition, or calculation protocol used to determine the reported tenacity and elongation values. The disclosure of ASTM D 3822 generally does not reasonably convey possession of particular amended limitation requiring ASTM D 3822/D3822M-14 (2020). As amended, the limitation is directed to a specific ASTM designation and version/reapproval year, which was not described in the specification as originally filed. Because the specification does not identify the specific ASTM D 3822/D3822M-14 (2020) standard and does not describe the tensile-testing steps used in the working examples, the specification does not establish that the reported tenacity and elongation values are obtained using the same measurement process required by the amended limitation. Accordingly, the originally filed disclosure does not reasonably convey to one skilled in the art that Applicant was in possession of the full scope of the amended measurement limitation at the time of filing. Claims 2 – 3 and 5- 16 are rejected because they depend from claims 1 and 4.
New 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:
i. Determining the scope and contents of the prior art.
ii. Ascertaining the differences between the prior art and the claims at issue.
iii. Resolving the level of ordinary skill in the pertinent art.
iv. 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 – 5, 12 – 13, and 15 are rejected under 35 U.S.C. 103 as being unpatentable over Xu (Machine Translation of CN101492837A, cited in the PTO-892 on February 23, 2026) in view of Sealey et al. (US6491788B2) and ASTM (ASTM International, 2020, PTO-892).
Xu teaches a preparation method of high polymerization bacterial cellulose fiber (page 1, line 5). The method comprises (1) dissolving bacterial cellulose with a polymerization degree of 1500 – 16000 in a solvent, and a bacterial cellulose solution with a mass fraction of 1% to 30% is prepared, filtered, and left to defoam to obtain a spinning solution; (2) the spinning solution in step (1) is sprayed through a spinneret, and then solidified and formed, and then stretched, washed, shaped, and dried to form a finished product (page 1, lines 35 – 39). Thus, Xu teaches the starting bacterial cellulose having a degree of polymerization of 1500 – 16000, which overlaps with the claimed range of 450 – 1500 recited in claims 1 – 2 and 4 – 5. In one example, the method comprises crushing and drying the bacterial cellulose with a polymerization degree of 1500, and then adding 1.5 mol/L lithium hydroxide / 0.65 mol/L thiourea system and dissolving at 0 ⁰C to make a 3.0% (mass percentage) solution. Spinning the solution, stirring for 12 hours, filtering, and defoaming and the spinning solution is sprayed out the spinneret through a metering pump, and enters the coagulation bath. The coagulation bath is water, the temperature is 10 ⁰C, and then it is stretched with saturated steam, the stretching temperature is 100 ⁰C, and the stretching ratio is 1.5 times. It was washed with water, oiled, and dried at a temperature of 120 ⁰C. The dried fibers are crimped at 90 ⁰C, heat-set at 130 ⁰C, and finally cut and packed to obtain a high-polymerization bacterial cellulose short fiber product (page 3, lines 5 – 12). In Example 2, the method comprises crushing and drying the bacterial cellulose with a polymerization degree of 3000, adding potassium permanganate / dimethylacetamide solution to activate it for 1 hour, and then taking out the lithium chloride / dimethylacetamide solution, dissolving the bacterial cellulose at 50 ⁰C to make a spinning solution with a concentration of 2.5%, stirring well, and letting stand for 12 h, filtering, and defoaming. The spinning solution is sprayed into the spinneret through a metering pump, and enters the coagulation bath. The coagulation bath is a 20% dimethylacetamide aqueous solution, the temperature is 15 ⁰C, and then the saturated steam is stretched, and the stretching temperature is 90 ⁰C, stretching ratio is 1.8 times, then washed with water, oiled, and dried at a temperature of 110 ⁰C. The dried fibers are crimped at 85 ⁰C, heat-set at 130 ⁰C, and finally cut and packed to obtain a high-polymerization bacterial cellulose fiber product (page 3, lines 15 – 25). Thus, Xu teaches examples of using bacterial cellulose having a degree of polymerization of 1500 as the starting material and using potassium permanganate, which is an oxidizing agent, to activate the bacterial cellulose with no dissolution step involved in the pre-treatment, which correspond to the limitations of claims 1 and 4. The method of Xu only contains the pre-treated bacterial cellulose as the only raw material, which corresponds to the limitations “100 wt% of a pre-treated bacterial cellulose” and “0” wt% of an additional cellulosic material of claims 1 and 4. Moreover, Example 2 demonstrates dissolving the bacterial cellulose activated by potassium permanganate into the lithium chloride / dimethylacetamide solution, which reads on the limitations “dissolve the cellulose and obtain a dope solution” in step (b) of claim 4. The molding in step (2) is completed by a dry-wet spinning, wherein the molding process is spinning, stretching, water washing, stretching, and drying, wherein the spinning solution is sprayed from a spinneret and then pass through an air gap, and then enter the spinning bath to solidify into silk (page 2, lines 24 – 26). The disclosure reads on the limitation of step (c) of claim 4. Furthermore, Xu teaches that the examples are only used to illustrate the invention and not to limit the scope of the invention. In addition, it should be understood that after reading the teaching of the invention, those skilled in the art can make various changes or modifications to the invention and these equivalent forms also fall within the scope defined by the claims of the invention (page 2, line 46; page 3, lines 1 – 2). Xu teaches that bacterial cellulose is more difficult to dissolve (page 2, line 34). Therefore, suitable solvents in step (1) are an inorganic solvent system, an organic solvent system, or an ionic liquid. The inorganic solvent system may be sodium hydroxide / thiourea. The organic solvent system may be N-methyl-morpholine-N-oxide (NMMO) (page 2, lines 3 – 6). In example 4, the bacterial cellulose with a polymerization degree of 2000 is pulverized and dried, and then a 50% (mass percent) NMMO aqueous solution is added for premixing to obtain an dissolved cellulose mixture suspension (Page 3, lines 42 – 44). Thus, Xu teaches the solvent system, which reads on the limitations of claim 15. These solvent system teachings are relied upon for the dissolution/solvent limitations, not as the claimed pre-treatment step.
However, Xu does not teach the fiber prepared has a tenacity of at least 4.5 grams/denier and an elongation of at least 10%. Xu does not teach the fiber has an average linear density in a range of 0.6 – 2.0 denier. Xu also does not explicitly teach that the tenacity and elongation of the fiber is measured in accordance with ASTM D 3822/D3822M-14 (2020).
Sealey et al. teach a process for making lyocell fibers from treated cellulose pulp (Abstract). Sealey et al. disclose that lyocell is a fiber composed of cellulose precipitated from an organic solution, and that lyocell fibers are produced principally for use in textile industry (Col. 2, lines 20 – 26). Sealey et al. teach that, in making lyocell fibers, the treated pulp is dissolved in an amine oxide solvent, preferably NMMO, and that the dissolved treated pulp is called a dope (Col. 15, lines 52 – 66). Sealey et al. teach that the dope is used to manufacture lyocell fibers, and that he dissolved treated pulp is forced through extrusion orifices to produce latent filaments or fibers that are later regenerated (Col. 16, lines 1 – 10 and 38 – 40). Sealey et al. teach that, once the alkaline pulp has been treated with oxidants, the treated pulp can either be washed in water and transferred to a bath of organic solvent, such as NMMO, for dissolution prior to lyocell molded body formation, or the treated pulp can be washed with water and dried for subsequent packaging, storage and/or shipping. Alternatively, the treated pulp can be dried and broken down into fragments for storage and/or shipping (Col. 14, lines 54 – 60). Sealey et al. further teach preferred lyocell fibers having dry elongation of about 8% to about 17%, more preferably about 12% to about 15%, and dry tenacities on the order of about 40 – 42 cN/tex (Col. 7, lines 7 – 20). In Example 11, Sealey et al. teach that the pulp of Example 4 is used to prepare a dope by dissolving the treated pulp in NMMO, and that the dope is spun into fibers by a dry jet/wet process (Col. 20, lines 16 – 22). Table 1 reports fiber fineness of 1.63 dtex and 1.25 dtex, dry tenacity of 40.9 cN/tex and 42.0 cN/tex, and dry elongation at break of 12.9% and 12.7% (Col. 20, lines 25 – 37). These teachings correspond to the tenacity, elongation, and linear density limitations of claims 1 and 3 – 4 because 40.9 – 42.0 cN/tex corresponds to about 4.63 – 4.76 g/denier, which is greater than the claimed tenacity of at least 4.5 g/denier; 12.7 – 12.9% elongation is greater than the claimed elongation of at least 10%; and 1.25 – 1.63 dtex corresponds to about 1.13 – 1.47 denier, which falls within the claimed average linear density range of 0.6 – 2.0 denier.
ASTM teaches a standard test method for measuring tensile properties of single textile fibers, including measuring breaking force and elongation at break and calculating breaking tenacity (page 1, Left Col., para. 1; Left Col., para. 6). ASTM further teaches that Test Method D3822 has been used extensively in the trade for acceptance testing (page 2, Left Col., para. 5). Thus, ASTM teaches that ASTM D 3822/D3822M-14 (2020) is a recognized single fiber tensile testing standard, which corresponds to the limitation of claims 1 and 4.
It would have been prima facie obvious for a person of ordinary skill in the art before the effective filing date of the claimed invention to modify the process as taught by Xu by applying the potassium permanganate activation step taught in the Example 2 of Xu to the bacterial cellulose having a degree of polymerization of 1500 in Example 1 of Xu prior to dissolution because Xu teaches the same general process of preparing high polymerization bacterial cellulose fibers from bacterial cellulose by dissolving the bacterial cellulose to form a spinning solution, spraying the spinning solution through a spinneret, passing through an air gap, entering a spinning bath, and subsequently stretching, washing, drying, and forming the finished fiber product. Xu further teaches that bacterial cellulose is difficult to dissolve and provides examples in which bacterial cellulose is activated with potassium permanganate before the later dissolution step. Therefore, one of ordinary skill in the art would have had a reason to apply the potassium permanganate activation step in Example 2 of Xu to the DP-1500 bacterial cellulose in Example 1 of Xu in order to facilitate dissolution and prepare the same type of high polymerization bacterial cellulose fiber taught by Xu. One of ordinary skill in the art would have had a reasonable expectation of success because the modification uses teachings from the same reference, directed to the same bacterial cellulose fiber preparation process, using the same type of bacterial cellulose starting material and the same general sequence of dissolution, spinning, coagulation, stretching, washing, and drying. Xu further teaches that the examples are illustrative and that those skilled in the art may make changes or modifications after reading the teaching of the invention. Thus, applying the potassium permanganate activation step disclosed in Xu to the DP-1500 bacterial cellulose process of Xu would have been no more than the predictable use of a known activation/pre-treatment step taught by Xu for the same material and same purpose.
It would have been prima facie obvious for a person of ordinary skill in the art before the effective filing date of the claimed invention to prepare the regenerated bacterial cellulose fibers of Xu to have tenacity, elongation, and linear density values within the ranges taught by Sealey et al. because Sealey et al. teach lyocell fibers, wherein lyocell is a cellulose fiber precipitated from an organic solution, and further teach preparing a cellulose dope by dissolving treated pulp in NMMO and spinning the dope into fibers by a dry jet/wet process. Sealey et al. also teach fiber property values including dry tenacity of 40.9 cN/tex and 42.0 cN/tex, dry elongation at break of 12.9% and 12.7%, and fiber fineness of 1.63 dtex and 1.25 dtex. These values correspond to tenacity greater than 4.5 g/denier, elongation greater than 10%, and average linear density within 0.6 – 2.0 denier, as recited in claims 1 and 3 – 4. One of ordinary skill in the art would have had a reason to use the fiber property of Sealey et al. with the regenerated bacterial cellulose fiber process of Xu because both Xu and Sealey et al. concern preparation of cellulosic fibers from dissolved cellulose spinning solutions/dopes. Xu provides the bacterial cellulose raw material, degree of polymerization, activation/pre-treatment before dissolution, and regenerated bacterial cellulose fiber process, while Sealey et al. provide support that regenerated cellulosic fibers prepared from cellulose dope/spinning processes are known to possess tenacity, elongation, and linear density values within the claimed ranges. Xu also teaches that the prepared bacterial cellulose fibers have improved breaking strength and modulus and are useful as high performance fibers. Thus, one of ordinary skill in the art would have been motivated to obtain Xu’s regenerated bacterial cellulose fibers with known regenerated cellulose fiber mechanical properties, such as tenacity, elongation, and fineness values taught by Sealey et al. One of ordinary skill in the art would have had a reasonable expectation of success because Xu teaches preparing bacterial cellulose fibers by dissolving bacterial cellulose to form a spinning solution, followed by spinning, coagulation, stretching, washing, and drying and Sealey et al. teach preparing regenerated cellulosic fibers by dissolving cellulose to form a dope and spinning the dope into fibers. Thus, both references concern preparation of cellulosic fibers from dissolved cellulose spinning solutions/dopes and Sealey et al. provide relevant guidance that regenerated cellulosic fibers prepared by such dope/spinning processes may possess the claimed tenacity, elongation, and linear density values.
Regarding the recitation that tenacity and elongation are measured in accordance with ASTM D 3822/D3822M-14 (2020), as discussed above, ASTM D 3822/D3822M-14 (2020) teaches a recognized standard test method for measuring tensile properties of single textile fibers, including breaking force, elongation at break, and breaking tenacity. ASTM D 3822/D3822M-14 (2020) further teaches that Test Method D3822 has been used extensively in the trade for acceptance testing. Thus, the art teaches that ASTM D 3822/D3822M-14 (2020) is recognized single fiber tensile testing standard for determining the same tensile properties recited in the claims. Although different tensile testing methods may produce different reported values, one of ordinary skill in the art seeking to determine and report the tenacity and elongation of regenerated cellulosic fibers in a standardized and accepted manner would have had reason to use ASTM D 3822/D3822M-14 (2020), because ASTM D 3822/D3822M-14 (2020) is recognized in the art for measuring the tensile properties of single textile fibers, including breaking tenacity and elongation at break, Therefore, it would have been obvious to measure the tenacity and elongation of the regenerated cellulosic fibers made obvious by Xu in view of Sealey et al. using ASTM D 3822/D3822M-14 (2020). The ASTM measurement limitation identifies the test method used to measure the tensile properties of the fiber, but it does not require a different fiber structure, different raw material, or different manufacturing step. Sealey et al. teach regenerated cellulosic fibers having tenacity and elongation values within the claimed ranges and Xu teaches preparing regenerated bacterial cellulose fibers by dissolution and spinning. Accordingly, the recitation of ASTM D 3822/D3822M-14 (2020) does not patentably distinguish the claimed fibers form the regenerated cellulosic fibers made obvious by the combined teachings of Xu, Sealey et al., and ASTM.
Regarding claims 12, Xu teaches washing as part of the bacterial cellulose fiber preparation process after spinning/ coagulation step. Although Xu may not explicitly state that the pre-treated bacterial cellulose is washed immediately after activation and before dissolution, it would have been prima facie obvious to wash the activated/pre-treated bacterial cellulose before the subsequent dissolution step in order to remove residual pre-treatment solution, improve purity, and facilitate later dissolution and spinning. Such washing would have been a routine processing step because Xu already teaches washing in the same bacterial cellulose fiber preparation process and Sealey et al. further corroborate that treated cellulose material may be washed before subsequent processing.
With respect to claim 13, Xu teaches crushing, pulverizing, and drying bacterial cellulose before dissolution in its examples, thereby teaching size reduction of the cellulose material as part of the preparation process. To the extent Xu does not explicitly disclose size reducing the bacterial cellulose after the pre-treatment step, it would have been prima facie obvious to size reduce the pre-treated bacterial cellulose before dissolution in order to improve handling, increase surface area, and facilitate formation of the spinning solution. Sealey et al. further support this processing rationale because Sealey et al. teach that treated pulp may be dried and broken into fragments, and that treated pulp may be physically broken down, for example by shredder, before being dissolved in an amine oxide-water mixture to form a dope..
Claims 6 and 10 are rejected under 35 U.S.C. 103 as being unpatentable over Xu (Machine Translation of CN101492837A, cited in the PTO-892 on February 23, 2026) in view of Sealey et al. (US6491788B2) and ASTM (ASTM International, 2020, PTO-892) as applied to claims 1 – 5, 12 – 13, and 15 above, and further in view of Cadwalader (WO2018/035245A1).
Xu and Sealey et al. teach the limitations discussed above.
However, Xu and Sealey et al. do not teach the pre-treatment step comprises an additional treatment for reducing the amount of metallic impurities in the bacterial cellulose, wherein the treatment comprising treating the bacterial cellulose with a chelating agent, wherein the chelating agent is ethylenediaminetetraacetic acid (EDTA).
Cadwalader teaches chelating agents for reducing metal content in some products and methods related thereto. In some embodiments, the products include one or more carbohydrates-based isolates, such as cellulose (para. [0041]). In some embodiments, the chelator is EDTA or salts thereof (para. [0052]).
It would have been prima facie obvious for a person of ordinary skill in the art before the effective filing date of the claimed invention to further modify the bacterial cellulose process as taught by Xu, as modified by Sealey et al., to include an additional treatment for reducing metallic impurities using chelating agent, such as EDTA, in view of Cadwalader because Cadwalader teaches that cellulose contains metal impurities and EDTA may be used to reduce the metal content. One would have had a reason to include such treatment because Cadwalader teaches reducing metal content in carbohydrate-based isolates, including cellulose, using chelating agents, and Xu’s bacterial cellulose is a cellulose material used to prepare regenerated cellulose fibers. Reducing metallic impurities would have been desirable to improve the purity of the cellulose material before subsequent dissolution and fiber formation. Therefore, one of the ordinary skill in the art would have had a reasonable expectation of success because Cadwalader teaches EDTA as a suitable chelator for reducing metal content in cellulose-containing carbohydrate-based isolates, and the proposed modification merely applies a known metal-reduction/chelation treatment to the cellulose material of Xu before subsequent processing. The modification would not require changing the bacterial cellulose raw material, dissolution step, spinning step, or regenerated fiber formation process of Xu. .
Claims 7 and 11 are rejected under 35 U.S.C. 103 as being unpatentable over Xu (Machine Translation of CN101492837A, cited in the PTO-892 on February 23, 2026) in view of Sealey et al. (US6491788B2) and ASTM (ASTM International, 2020, PTO-892) as applied to claims 1 – 5, 12 – 13, and 15 above, and further in view of Wang et al. (Machine Translation of CN105926065A, cited in the PTO-892 on February 23, 2026).
Xu and Sealey et al. teach the limitations discussed above.
However, Xu and Sealey et al. do not teach that the oxidizing agent is an agent recited in claim 7. Xu and Sealey et al. do not teach that the pre-treatment step is carried out at a temperature ranging between 30 – 100 ⁰C for a time-period ranging from 1 to 20 hours.
Wang et al. teach a preparation method for a bacterial cellulose nanofiber-based oriented macroscopic fiber and the invention uses bacterial cellulose wet film as a raw material and oxidize and homogenize the bacterial cellulose with a TEMPO oxidation system, wherein the oxidation system contains the oxidizing agent NaClO (page 2, lines 22 – 24). Wang et al. further teach that the treatment of bacterial cellulose using oxidizing agent is performed in a sealed system with the temperature raised to 80 ⁰C and the system is stirred for 0.5 to 2 hours (page 3, lines 15 – 16). Thus, Wang et al. is relied upon for teaching sodium hypochlorite-containing oxidative treatment of bacterial cellulose, not for teaching a dissolution solvent system.
It would have been prima facie obvious for a person of ordinary skill in the art before the effective filing date of the claimed invention to substitute the potassium permanganate as taught by Xu with NaClO in view of Wang et al. because both Xu and Wang et al. teach methods of preparing cellulose fiber using oxidizing agent. One would have been motivated to substitute the potassium permanganate as taught by Xu with NaClO in view of Wang et al. because Xu teaches activating bacterial cellulose with an oxidizing agent, potassium permanganate, before dissolution, and Wang et al. teach treating bacterial cellulose with TEMPO oxidation system containing NaClO as the oxidizing agent. Thus, Wang et al. provide specific teaching that sodium hypochlorite may be used as an oxidizing agent for bacterial cellulose treatment. Therefore, one of the ordinary skill in the art would have had a reasonable expectation of success to substitute the potassium permanganate as taught by Xu with NaClO in view of Wang et al. because both Xu and Wang et al. teach oxidative treatment of bacterial cellulose before forming cellulose fibers and Wang et al. explicitly teach using NaClO-containing TEMPO oxidation treatment on bacterial cellulose. The substitution of NaClO for the oxidizing agent in the bacterial cellulose activation step of Xu would have involved applying a known oxidizing agent taught by Wang et al. for the same type of cellulose material, which is bacterial cellulose, and would have been expected to yield a treated bacterial cellulose suitable for subsequent fiber preparation. Wang et al. further teach treatment at 80 ⁰C for 0.5 to 2 hours, which corresponds to the temperature and time limitations recited in claim 11.
Claim 8 is rejected under 35 U.S.C. 103 as being unpatentable over Xu (Machine Translation of CN101492837A, cited in the PTO-892 on February 23, 2026) in view of Sealey et al. (US6491788B2) and ASTM (ASTM International, 2020, PTO-892) as applied to claims 1 – 5, 12 – 13, and 15 above, and further in view of Rodriguez-Chanfrau et al. (Cellulose Chemistry and Technology, 2017, Vol. 51, Issue 7 – 8, page 673 – 680, cited in the PTO-892 on February 23, 2026).
Xu and Sealey et al. teach the limitations discussed above.
However, Xu and Sealey et al. do not teach that the pre-treatment agent is the acid, wherein the acid is the agent recited in claim 8.
Rodriguez-Chanfrau et al. teach that the bacterial cellulose is modified by acid treatment with sulphuric acid. The results show that the solubility of the initial sample increased by approximately 18% while the yield exceeds 80% (Abstract). Thus, Rodriguez-Chanfrau et al. is relied upon for teaching sulphuric acid treatment/modification of bacterial cellulose before subsequent processing, not for teaching sulphuric acid as the dissolution solvent used to form the spinning/dope solution.
It would have been prima facie obvious for one of the ordinary skill in the art before the effective filing date of the claimed invention to modify the bacterial cellulose pre-treatment process taught by Xu by selecting sulphuric acid as the pre-treatment agent in view of Rodriguez-Chanfrau et al. because Xu teaches preparing regenerated bacterial cellulose fibers by dissolving bacterial cellulose to form a spinning solution and also teaches that bacterial cellulose is difficult to dissolve, while Rodriguez-Chanfrau et al. teach that sulphuric acid treatment of bacterial cellulose increases the solubility of the bacterial cellulose. Thus, one of ordinary skill in the art would have recognized sulphuric acid treatment as a suitable known treatment for improving the solubility of bacterial cellulose before subsequent dissolution and fiber formation. One of ordinary skill in the art would have had a reason to make the modification because improving the solubility of bacterial cellulose would facilitate the subsequent dissolution step required in the process of Xu. Rodriguez-Chanfrau et al. specifically teach that bacterial cellulose modified by sulphuric acid treatment exhibited about an 18% increase in solubility while maintaining a yield exceeding 80%. Therefore Rodriguez-Chanfrau et al. provide a specific reason to use sulphuric acid treatment on bacterial cellulose before further processing. One of ordinary skill in the art would have had a reasonable expectation of success because Rodriguez-Chanfrau et al. explicitly apply sulphuric acid treatment to bacterial cellulose and report increased solubility with a yield exceeding 80%. Thus, applying the sulphuric acid treatment taught by Rodriguez-Chanfrau et la. to Xu’s bacterial cellulose before dissolution would have been expected to provide treated bacterial cellulose suitable for subsequent dissolution and regenerated fiber formation.
Claim 9 is rejected under 35 U.S.C. 103 as being unpatentable over Xu (Machine Translation of CN101492837A, cited in the PTO-892 on February 23, 2026) in view of Sealey et al. (US6491788B2) and ASTM (ASTM International, 2020, PTO-892) as applied to claims 1 – 5, 12 – 13, and 15 above, and further in view of Ring et al. (US4788146)
Xu and Sealey et al. teach the limitations discussed above.
However, Xu and Sealey et al. do not teach that the pre-treatment agent is the alkali, wherein the alkali is the agent recited in claim 9.
Ring et al. teach liquid loaded pads prepared from pellicles of microbially-produced cellulose obtained by culturing Acetobacter xylinum (Abstract). Ring et al. teach that the materials comprise a liquid loaded pad of microbially produced cellulose, particularly cellulose produced from the culture of Acetobacter xylinum, and that the pellicle is removed from the nutrient, treated with sodium hydroxide, neutralized, and washed with water to obtain a water-loaded pellicle of microbial cellulose (Col. 3, lines 40 – 50). Ring et al. further teach in Example 1 that the pressed bacterial cellulose pellicle is transferred to a 3% NaOH solution and allowed to soak for 12 hours, followed by neutralization with hydrochloric acid and repeated washing with distilled water until the rinse water remained neutral (Col. 4, lines 47 – 65). Ring et al. also teach that the NaOH treatment may be modified, with equivalent results, by boiling the pellicle in a 1 to 10% solution of NaOH or KOH for up to 1 hour or more, followed by neutralization and washing (Col. 7, lines 3 – 15). These teachings correspond to claim 9 because Ring et al. teach treating microbial/bacterial cellulose with an alkali, including sodium hydroxide or potassium hydroxide, as a separate treatment step before subsequent neutralization and washing.
It would have been prima facie obvious for a person of ordinary skill in the art before the effective filing date of the claimed invention to further modify the bacterial-cellulose pre-treatment/activation process taught by Xu, as modified by Sealey et al., by selecting an alkali, such as sodium hydroxide or potassium hydroxide, as the pre-treatment agent in view of Ring et al., thereby arriving at the limitation that the pre-treatment agent is an alkali, as recited in claim 9, because Ring et al. teach microbially produced cellulose from Acetobacter xylinum, wherein the pellicle is treated with sodium hydroxide, neutralized, and washed with water, and further teach that the pellicle may be boiled in a 1 to 10% solution of NaOH or KOH. One of ordinary skill in the art would have had a reason to make the modification because Xu uses bacterial cellulose as the cellulosic raw material for preparing regenerated bacterial-cellulose fibers and Ring et al. teach that microbial/bacterial cellulose produced from Acetobacter xylinum may be treated with sodium hydroxide or potassium hydroxide as a separate treatment step before neutralization and washing. Ring et al. further teach that the NaOH treatment is for removal of entrapped Acetobacter xylinum bacteria and bacterial residue from the pellicle. Thus, one of ordinary skill in the art would have been motivated to use an alkali pre-treatment on Xu’s bacterial cellulose to remove bacterial residue/impurities and prepare the bacterial cellulose material before subsequent dissolution and fiber formation. One of ordinary skill in the art would have had a reasonable expectation of success because Ring et al. apply sodium hydroxide treatment to microbial/bacterial cellulose and further teach NaOH or KOH treatment with equivalent results, followed by neutralization and washing. Therefore, applying the alkali treatment taught by Ring et al. to Xu’s bacterial cellulose would have been expected to provide treated bacterial cellulose that remains suitable for subsequent dissolution and regenerated fiber preparation.
Claim 14 is rejected under 35 U.S.C. 103 as being unpatentable over Xu (Machine Translation of CN101492837A, cited in the PTO-892 on February 23, 2026) in view of Sealey et al. (US6491788B2) and ASTM (ASTM International, 2020, PTO-892) as applied to claims 1 – 5, 12 – 13, and 15 above, and further in view of Bhushan et al. (US7938993B2)
Xu and Sealey et al. teach the limitations discussed above.
However, Xu and Sealey et al. do not teach that the pre-mix is prepared by mixing the cellulosic raw material and the solvent in step (b), for a time-period between 0 to 6 hours, with or without shear at a temperature between 25 to 90 ⁰C.
Bhushan et al. teach a process for preparation of a cellulose solution for spinning of fibers, filaments, or films, wherein cellulose is activated in a mixture containing cellulose, tertiary amine oxide solvent and water for a period sufficient to allow swelling of the cellulose, followed by dissolution of cellulose in the solvent by heating for removal of water (Abstract). Bhushan et al. teach that cellulose is mixed with aqueous solution of 40 – 70% amine oxide to enhance cellulose activation at 70 – 115 ⁰C, and that activation is complete if the mass is kept for 2 – 60 minutes, after which cellulose dissolution is fast and a good homogenous cellulose solution is made (Col. 2, lines 62 – 67; Col. 3, lines 1 – 10). Bhushan et al. further teach that the premixing of cellulose with amine oxide and activation are carried out at 70 – 115 ⁰C, preferably 80 – 90 ⁰C, for 20 – 60 minutes, preferably 30 – 40 minutes (Col. 4, lines 3 – 5). Bhushan et al. also teach that cellulose is mixed with aqueous amine-oxide solution under conditions where no dissolution of cellulose takes place and only the cellulose absorbs the amine oxide uniformly, and the mixture is allowed to remain for some time to activate the cellulose (Col. 3, lines 47 – 54). In Example 1, Bhushan et al. teach that pulp and NMMO/water mixture are fed into the premixer and mixed for 60 minutes and 80 ⁰C, during which the pulp absorbs water present in aqueous NMMO solution and becomes activated, facilitating penetration of NMMO into the interior of the fiber matrix (Col. 6, lines 31 – 39). These teachings correspond to claim 14 because Bhushan et al. teach preparing a cellulose/amine oxide premix by mixing cellulose with aqueous amine oxide before dissolution, and the taught premixing/activation conditions, including 60 minutes at 80 ⁰C and preferred 20 – 60 minutes at 80 – 90 ⁰C, fall within the claimed time period of 0 to 6 hours and temperature range of 25 ⁰C to 90 ⁰C.
It would have been prima facie obvious for a person of ordinary skill in the art before the effective filing date of the claimed invention to further modify the premix/dissolution step taught by Xu, as modified by Sealey et al., by preparing the premix under the time and temperature conditions in view of Bhushan et al., thereby arriving at the limitation that the premix is prepared by mixing the cellulosic raw material and solvent for a time period between 0 to 6 hours, with or without shear, at a temperature between 25 °C to 90 ⁰C, as recited in claim 14, because Bhushan et al. teach that the premixing of cellulose with amine oxide and activation are carried out at 70 – 115 ⁰C, preferably 80 – 90 ⁰C, for 20 – 60 minutes, preferably 30 – 40 minutes. Bhushan et al. also teach in Example 1 that pulp and NMMO/water mixture are fed in the premixer and mixed for 60 minutes at 80 ⁰C. One of ordinary skill in the art would have had a reason to make the modification because Xu teaches preparing regenerated bacterial-cellulose fibers by dissolving bacterial cellulose to form a spinning solution and Bhushan et al. teach premixing cellulose with aqueous amine oxide before dissolution to activate the cellulose and facilitate formation of a homogeneous cellulose solution. Bhushan et al. teach that the swelling of cellulose is enhanced above 70 ⁰C in the presence of an amine oxide-water mixture, that after such activation cellulose dissolution is fast and good homogeneous cellulose solution is made with the treated cellulose, and that solution homogeneity is important for smooth spinning performance and final product properties. Thus, one of ordinary skill in the art would have been motivated to use premixing time and temperature conditions of Bhushan et al. in Xu’s cellulose solvent premix step to improve swelling, activation, dissolution, and dope homogeneity before spinning. One of ordinary skill in the art would have had a reasonable expectation of success because Bhushan et al. explicitly teach premixing cellulose with aqueous amine oxide under conditions where no dissolution takes place and the cellulose absorbs amine oxide uniformly, followed by further processing to form an extrudable/spinnable cellulose solution. Bhushan et al. also demonstrate in Example 1 that mixing pulp with NMMO/water for 60 minutes at 80 ⁰C activates the pulp and facilitates penetration of NMMO into the fiber matrix, followed by complete dissolution and spinning. Because these time and temperature conditions fall within the claimed 0 – 6 hour and 25 – 90 ⁰C ranges, applying the known premixing conditions of Bhushan et al. to Xu’s premix/dissolution process would have been expected to successfully form a cellulose dope suitable for subsequent regenerated fiber formation.
Claim 16 is rejected under 35 U.S.C. 103 as being unpatentable over Xu (Machine Translation of CN101492837A, cited in the PTO-892 on February 23, 2026) in view of Sealey et al. (US6491788B2) and ASTM (ASTM International, 2020, PTO-892) as applied to claims 1 – 5, 12 – 13, and 15 above, and further in view of Anaya-Esparza et al. (Processes, 2020, Vol. 8, Issue 11, cited in the PTO-892 on February 23, 2026).
Xu and Sealey et al. teach the limitations discussed above.
However, Xu and Sealey et al. do not teach the pre-mix further comprises an additive, wherein the additive is the agent recited in claim 16.
Anaya-Esparza et al. teach that CMC-TiO2 shows antimicrobial activity against E. coli and S. aureus, associated with the ROS generation ability of TiO2 with cell growth inhibition properties (page 13, para. 1).
It would have been prima facie obvious for a person of ordinary skill in the art before the effective filing date of the claimed invention to further modify the premix used in Xu’s regenerated cellulose fiber process by including TiO2 as an additive in view of Anaya-Esparza et al., thereby arriving at the limitation that the premix further comprises an additive, wherein the additive is TiO2, as recited in claim 16, because Xu teaches preparing a cellulose premix/spinning solution for forming regenerated cellulose fibers, and Anaya-Esparza et al. teach incorporating TiO2 into a cellulose-based material to provide antimicrobial activity against E.coli and S.aureus. Thus, Anaya-Esparza et al. provide a specific teaching that TiO2 is a useful additive for cellulose-based materials. One of ordinary skill in the art would have had a reason to make the modification because incorporating TiO2 into Xu’s cellulose premix would have predictably imparted the antimicrobial property taught by Anaya-Esparza et la. to the resulting cellulose material. Xu teaches preparing regenerated cellulose fibers from a cellulose-containing premix/spinning solution and Anaya-Esparza et al. teach that TiO2-containing cellulose-based material shows antimicrobial activity. Therefore, one of ordinary skill in the art would have been motivated to include TiO2 in Xu’s premix to obtain a TiO2-containing regenerated cellulose fiber having antimicrobial functionality. One of ordinary skill in the art would have had a reasonable expectation of success because Anaya-Esparza et al. teach TiO2 in a cellulose-based material and report antimicrobial activity associated with TiO2. Accordingly, incorporating the known TiO2 additive into Xu’s cellulose premix would have been expected to provide a TiO2-containing cellulose material with antimicrobial benefit taught by Anaya-Esparza et al.
Responses to Applicant’s Remarks:
Applicant’s Remarks, filed June 23, 2026, have been fully considered and are found to be not persuasive.
Applicant argues that Xu merely discloses dissolution and spinning of high polymerization bacterial cellulose, but does not disclose or suggest a separate non-dissolution pre-treatment step for obtaining pre-treated bacterial cellulose having a controlled DP in the range of 450 – 1500. Applicant also argues that Xu’s lithium hydroxide/urea and sodium hydroxide systems are dissolution solvent systems, not pre-treatment steps, and therefore Xu does not teach the claimed pre-treatment before dissolution. Applicant further argues that Xu does not disclosure regenerated cellulose fibers simultaneously exhibiting a tenacity of at least 4.5 g/denier and an elongation of at least 10%. However, the arguments are not persuasive with respect to the newly formulated rejection. The claimed pre-treatment is distinguished from dissolution because the pre-treatment is the treatment or activation of bacterial cellulose before the later dissolution step used to form the spinning/dope solution. The present rejection does not rely on Xu’s lithium hydroxide/urea or sodium hydroxide solvent systems as the claimed pre-treatment step. Instead, Xu is relied upon for teaching bacterial cellulose, high polymerization bacterial cellulose fiber preparation, dissolution to form a spinning solution, spinning through a spinneret, air-gap/coagulation processing, stretching, washing, and drying. Xu is also relied upon for teaching bacterial cellulose having a DP of 1500 in Example 1 and a separate potassium permanganate activation step before dissolution in Examples 2 and 3. Thus, it would have been obvious to apply Xu’s potassium permanganate step to Xu’s DP-1500 bacterial cellulose process before dissolution. Sealey et al. are further relied upon to show that regenerated cellulosic fibers prepared from cellulose dope/spinning processes are known to have tenacity, elongation, and linear density values within the claimed ranges. Therefore, the rejection is based on the combined teachings of Xu and Sealey et al., not on Xu alone.
Applicant argues that Xu does not recognize that controlling DP within the claimed range improves dissolution behavior and enables preparation of regenerated cellulose fibers having the claimed balance of high tenacity and elongation. Applicant further argues the Xu does not provide motivation to pre-treat bacterial cellulose before dissolution to control DP within 450 – 1500. Applicant’s argument is not persuasive because Xu teaches the problem that bacterial cellulose is difficult to dissolve and further teaches an activation step using potassium permanganate before dissolution in the same general bacterial cellulose fiber preparation process. Xu also teaches that the examples are illustrative and that modifications may be made by one of ordinary skill in the art. Thus, one of ordinary skill in the art would have had a reason to apply the activation step taught in Xu’s potassium permanganate example to the DP-1500 bacterial cellulose of the Example 1 of Xu in order to facilitate dissolution and prepare a bacterial cellulose spinning solution. One of ordinary skill in the art would have had a reasonable expectation of success because the modification uses teachings from the same references, directed to the same material and same overall fiber-forming process.
Applicant argues that Xu does not disclose the claimed washing and size reduction limitations as applied to pre-treated bacterial cellulose before dissolution. Applicant further argues that Xu’s disclosure of washing and drying occurs after fiber formation and does not teach washing or size reducing the pre-treated bacterial cellulose prior to dissolution. However, the argument is not persuasive. Xu teaches crushing or pulverizing bacterial cellulose as part of preparing the bacterial cellulose material for dissolution and spinning, and Xu further teaches washing as part of the bacterial cellulose fiber preparation process. As set forth in the rejection on page 23, although Xu may not explicitly state that the potassium permanganate activated bacterial cellulose is washed immediately after activation and before dissolution, it would have been obvious to wash the activated bacterial cellulose before subsequent dissolution in order to remove residual pre-treatment solution, improve purity, and facilitate later dissolution and spinning. Sealey et al. further support the routine nature of washing treated cellulose material before dissolution because Sealey et al. teach that treated pulp may be washed in water and transferred to an organic solvent such as NMMO for dissolution. It would have been obvious to size reduce pre-treated bacterial cellulose before dissolution to improve handling, increase surface area, and facilitate formation of the spinning solution. Accordingly, the washing and size reduction limitations of claims 12 – 13 would have been obvious processing steps in view of the combined teachings of Xu and Sealey et al.
Applicant argues that Cadwalader is directed to reducing metallic impurities present in cellulose materials using chelating agent, such as EDTA, but does not disclose reducing the DP of bacterial cellulose prior to dissolution. Applicant further argues that Cadwalader does not disclose preparation of regenerated cellulose spinning dopes from pre-treated bacterial cellulose or regenerated cellulosic fibers exhibiting the claimed balance of tenacity and elongation. However, the argument is not persuasive because Cadwalader is not relied upon to teach the entire regenerated bacterial cellulose fiber process, the DP range, or the claimed tenacity and elongation. Xu in view of Sealey et al. is relied upon for the base process and fiber property limitations. Cadwalader is relied upon only for the additional dependent limitations recited in claims 6 and 10, which is the additional treatment for reducing metallic impurities using a chelating agent, wherein the chelating agent is EDTA. Cadwalader teaches reducing metal content in carbohydrate-based isolates, including cellulose, using chelating agents, and teaches EDTA or salts thereof as suitable chelators. Therefore, it would have been obvious to include an EDTA treatment in Xu’s bacterial cellulose process to reduce metallic impurities before subsequent dissolution and fiber formation.
Applicant argues that Wang et al. is directed to preparation of bacterial cellulose nanofiber-based directionally arranged macrofibers using TEMPO oxidation, sodium hypochlorite systems, homogenization, wet spinning, and crosslinking operations. Applicant further argues that Wang et al. do not relate to formation of regenerated cellulose fibers, but instead relates to nanofiber-based macrofibers, and does not disclose a distinct pre-treatment step for controlling optimization of DP so that regenerated cellulosic fibers having high tenacity and elongation could be obtained. Applicant’s argument is not persuasive because Wang et al. is not relied upon to teach the entire regenerated bacterial cellulose fiber process or the claimed tenacity and elongation. Xu in view of Sealey et al. is relied upon for the base regenerated bacterial cellulose fiber process and the fiber property limitations. Wang et al. is relied upon only for the additional dependent limitations of claims 7 and 11, which is the use of sodium hypochlorite as an oxidizing agent and treatment under the recited temperature/time conditions. Wang et al. teach treating bacterial cellulose using a TEMPO oxidation system containing NaClO and further teach treatment at 80 ⁰C for 0.5 to 2 hours. Because Xu already teaches activating bacterial cellulose using an oxidizing agent before dissolution, one of ordinary skill in the art would have had a reason to select NaClO as an alternative oxidizing agent for bacterial cellulose treatment in view of Wang et al., with a reasonable expectation of success because Wang et al. apply NaClO-containing oxidation treatment to bacterial cellulose.
Applicant argues that Rodriguez-Chanfrau et al. is directed to sulphuric acid treatment of bacterial cellulose for increasing cellulose solubility, but does not disclose the presently claimed process including formation of regenerated cellulosic fibers from bacterial cellulose by controlled optimization of DP prior to dissolution and regeneration. Applicant further argues that Rodriguez-Chanfrau et al. do not disclose regenerated cellulosic fibers exhibiting the claimed tenacity and elongation properties. However, the arguments are not persuasive because Rodriguez-Chanfrau et al. is not relied upon to teach the entire process of claim 4or the claimed fiber properties. Xu in view of Sealey et al. is relied upon for the base bacterial cellulose regenerated fiber process and the claimed property values. Rodriguez-Chanfrau et al. is relied upon only for the additional dependent limitation of claim 8, which is that the pre-treatment agent is an acid, wherein the acid is sulphuric acid. Rodriguez-Chanfrau et al. teach sulphuric acid treatment of bacterial cellulose and report increased solubility of the initial bacterial cellulose sample. Because Xu teaches that bacterial cellulose is difficult to dissolve before forming a spinning solution, one of ordinary skill in the art would have had a reason to use the sulphuric acid treatment taught by Rodriguez-Chanfrau et al. to improve bacterial cellulose solubility before the subsequent dissolution and fiber-forming steps taught by Xu.
Applicant argues that the cited references do not disclose the claimed alkali pre-treatment of bacterial cellulose before dissolution. Applicant’s argument is not persuasive in view of Ring et al. Ring et al. teach microbially produced cellulose from Acetobacter xylinum, wherein the pellicle is treated with sodium hydroxide, neutralized, and washed with water. Ring et al. further teach that the NaOH treatment may be modified by boiling the pellicle in a 1 to 10% solution of NaOH or KOH, followed by neutralization and washing. Accordingly, Ring et al. teach alkali treatment of microbial/bacterial cellulose as a separate treatment step. Because Xu uses bacterial cellulose as the cellulosic raw material for preparing regenerated bacterial cellulose fibers, one of ordinary skill in the art would have had a reason to apply the alkali treatment taught by Ring et al. to Xu’s bacterial cellulose to remove bacterial residue/impurities and prepare the bacterial cellulose material before subsequent dissolution and fiber formation.
Applicant argues that the prior art does not disclose the claimed premix time and temperature conditions. However, the argument is not persuasive in view of Bhushan et al. Bhushan et al. teach premixing cellulose with amine oxide and activation at 70 – 115 ⁰C, preferably 80 – 90 ⁰C, for 20 – 60 minutes, preferably 30 – 40 minutes. Bhushan et al. further teach in Example 1 that pulp and NMMO/water mixture are fed into a premixer and mixed for 60 minutes at 80 ⁰C, during which the pulp absorbs water present in the aqueous NMMO solution and becomes activated, facilitating penetration of NMMO into the interior of the fiber matrix. These conditions fall within the claimed time period of 0 to 6 hours and temperature range of 25 ⁰C to 90 ⁰C. Because Xu teaches preparing regenerated bacterial cellulose to form a spinning solution, one of ordinary skill in the art would have been motivated to use the premixing time and temperature conditions of Bhushan et al. to improve swelling, activation, dissolution, and dope homogeneity before spinning, with a reasonable expectation of success because Bhushan et al. demonstrate such premixing conditions in a cellulose/NMMO system.
Applicant argues that Anaya-Esparza et al. is directed to cellulose-based antimicrobial compositions incorporating TiO2 particles. Applicant further argues that Anaya-Esparza et al. do not disclose or suggest pre-treatment of bacterial cellulose for controlled optimization of DP prior to dissolution and regeneration, does not disclose regenerated cellulose spinning dopes, and does not disclose regenerated cellulosic fibers exhibiting the claimed balance of tenacity and elongation. Applicant’s argument is not persuasive because Anaya-Esparza et al. is not relied upon to teach the entire regenerated bacterial cellulose fiber process, the claimed DP range, or the claimed tenacity and elongation. Xu in view of Sealey et al. is relied upon for the base bacterial cellulose regenerated fiber process and the claimed property values. Anaya-Esparza et al. is relied upon only for the additional dependent limitation of claim 16, which is that the premix further comprises an additive, wherein the additive is TiO2. Anaya-Esparza et al. teach TiO2-containing cellulose-based materials and teach that CMC- TiO2 shows antimicrobial activity against E.coli and S.aureus. therefore, it would have been obvious to include TiO2 as an additive in Xu’s cellulose premix to impart antimicrobial functionality to the resulting cellulose material or fiber, with a reasonable expectation of success because Anaya-Esparza et al. teach TiO2 in a cellulose-based material and report the associated antimicrobial activity.
Applicant argues that Xu, Cadwalader, Wang et al., Rodriguez-Chanfrau et al., and Anaya-Esparza et al., taken alone or in combination, do not render the currently amended claims obvious. However, the argument is not persuasive with respect to the newly formulated rejections. The present rejections do not rely on any single secondary reference to teach the entire claimed invention. Instead, Xu is relied upon for the bacterial cellulose raw material, DP teaching, activation/pre-treatment before dissolution, dissolution/spinning process, and regenerated bacterial cellulose fiber preparation. Sealey et al. is relied upon for known regenerated cellulose fiber property values, including tenacity, elongation, and linear density. The additional secondary references are relied upon only for specific dependent limitations. Accordingly, the combination of references provides articulated reasons to modify Xu’s bacterial cellulose regenerated fiber process and provides a reasonable expectation of success for each modification.
Conclusion
No claim is found to be allowable.
Applicant's amendment necessitated the maintained / new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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/H.Y.L./Examiner, Art Unit 1693
/SCARLETT Y GOON/Supervisory Patent Examiner, Art Unit 1693
