Prosecution Insights
Last updated: April 19, 2026
Application No. 18/140,459

Controlled release fertilizer containing ammonium polyphosphate and its preparation methods

Non-Final OA §103§112
Filed
Apr 27, 2023
Examiner
SMITH, JENNIFER A
Art Unit
1731
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Maoshi Agricultural Technology Co. Ltd.
OA Round
1 (Non-Final)
61%
Grant Probability
Moderate
1-2
OA Rounds
3y 2m
To Grant
88%
With Interview

Examiner Intelligence

Grants 61% of resolved cases
61%
Career Allow Rate
530 granted / 863 resolved
-3.6% vs TC avg
Strong +26% interview lift
Without
With
+26.3%
Interview Lift
resolved cases with interview
Typical timeline
3y 2m
Avg Prosecution
53 currently pending
Career history
916
Total Applications
across all art units

Statute-Specific Performance

§101
0.6%
-39.4% vs TC avg
§103
47.4%
+7.4% vs TC avg
§102
22.9%
-17.1% vs TC avg
§112
22.8%
-17.2% vs TC avg
Black line = Tech Center average estimate • Based on career data from 863 resolved cases

Office Action

§103 §112
DETAILED ACTION Notice of Pre-AIA or AIA Status The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . Election/Restriction Applicant’s election without traverse of the invention of Group I (claims 1-9) in the reply filed on 01/11/2026 is acknowledged. Claim 10 is withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected invention, there being no allowable generic or linking claim. Claim Rejections - 35 USC § 112 The following is a quotation of 35 U.S.C. 112(b): (b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention. The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph: The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention. Claims 1-9 are rejected 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. In regard to claim 1, the term “multiple metallic medium and trace elements” in lines 5 and 8is unclear. The term “metallic medium” is not a term of the art. It appears the “metallic medium” elements may refer to “secondary nutrients” like calcium and magnesium or “medium elements” like sulfur but the limitation is ambiguous. Where applicant acts as his or her own lexicographer to specifically define a term of a claim contrary to its ordinary meaning, the written description must clearly redefine the claim term and set forth the uncommon definition so as to put one reasonably skilled in the art on notice that the applicant intended to so redefine that claim term. Process Control Corp. v. HydReclaim Corp., 190 F.3d 1350, 1357, 52 USPQ2d 1029, 1033 (Fed. Cir. 1999). In regard to claim 1, the limitation “fertilizer envelopes coated on a surface of the fertilizer core particles respectively” in lines 2-3 is unclear. The limitation implies coverage of only one face or portion of the particle. The use of the word “respectively” is unclear as to what is being referred to. Claim Rejections - 35 USC § 103 In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status. The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action: A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made. The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows: 1. Determining the scope and contents of the prior art. 2. Ascertaining the differences between the prior art and the claims at issue. 3. Resolving the level of ordinary skill in the pertinent art. 4. Considering objective evidence present in the application indicating obviousness or nonobviousness. Claim 1 is rejected under 35 U.S.C. 103 as being unpatentable over Zhang (CN-102718588). In regard to claim 1, Zhang teaches a controlled release fertilizer containing ammonium polyphosphate (e.g. composite fertilizer granules containing ammonium polyphosphate) [paras. 0016-0018], wherein: the controlled release fertilizer comprises fertilizer core particles and fertilizer envelopes coated on a surface of the fertilizer core particles respectively (e.g. fertilizer granules are coated with powder and oil) [0018]; the fertilizer core particles contain phosphorus source, nitrogen source, potassium source and multiple metallic medium and trace element sources (e.g. potassium fertilizer, nitrogen fertilizer, and trace elements mixed with ammonium polyphosphate phosphorous source) [0017]; P (phosphorus) in the phosphorus source is only from ammonium polyphosphate which has a degree of polymerization in a range of 5 to 20 (e.g. ammonium polyphosphate with a degree of polymerization not greater than 10) [0016] and 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) See MPEP 2144.05] and has a chelating effect on metallic medium and trace elements in the multiple metallic medium and trace element sources (e.g. ammonium polyphosphate can form completely water-soluble chelates with trace elements such as zinc and iron, which can simultaneously supplement phosphorus fertilizer and trace elements to plants) [0034]. Claim 9 is rejected under 35 U.S.C. 103 as being unpatentable over Zhang (CN-102718588) as applied to claim 1 above, and further in view of Wynnyk et al. (US Patent Publication No. 2004/0016276). In regard to claim 9, Zhang discloses the controlled release fertilizer according to claim 1, wherein the fertilizer envelopes include oil or powder (e.g. fertilizer granules are coated with powder and oil) [0018] but does not explicitly recite polyurethane envelopes. Wynnyk et al. is directed to controlled release fertilizer material surrounded by a protective urethane-containing coating [abstract], typically polyurethane [0031]. Wynnyk et al. describe that it is known in the art to coat particulate plant nutrient with oil to improve the release profiles of the plant nutrient [0007]. Wynnyk describes polyurethane used to produce a coating that is less susceptible to damage during the mechanical handing of the fertilizer material [0020]. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to include a polyurethane coating (e.g. envelope) as a component of Zhang’s fertilizer product in addition to or in place of the oil coating disclosed. One of ordinary skill in the art would have been motivated to do so to improve controlled release of fertilizer nutrients [0020; 0005]. Claims 1-4 are rejected under 35 U.S.C. 103 as being unpatentable over Walker (WO-2022133548) in view of Wang et al. (ACS omega, 2021). In regard to claim 1, Walker teaches a controlled release fertilizer (e.g. nutrients in the form that are sustained release) [pg. 14, lines 29-30] containing ammonium polyphosphate (e.g. phosphorous in the form of ammonium polyphosphate) [pg. 18, line 28], wherein: the controlled release fertilizer comprises fertilizer core particles and fertilizer envelopes coated on a surface of the fertilizer core particles respectively (e.g. fertilizer granule particles can be coated) [pg. 17, lines 4-7]; the fertilizer core particles contain phosphorus source, nitrogen source, potassium source and multiple metallic medium and trace element sources (e.g. NPKS in addition to micronutrients including zinc, copper, iron, manganese, boron, molybdenum and secondary nutrients calcium, magnesium and silicon [pg. 19, last para.]. Walker does not explicitly disclose wherein the P (phosphorus) in the phosphorus source is only from ammonium polyphosphate which has a degree of polymerization in a range of 5 to 20. Wang et al is directed to short-chain ammonium polyphosphate [abstract], wherein the degree of polymerization is in a range of 2 to 20 [pg. 18811, first col.]. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to utilize a short-chain ammonium polyphosphate as the ammonium polyphosphate material disclosed in Walker. One of ordinary skill in the art would have been motivated to do so because short-chain APPs are effective phosphate fertilizers and are known to increase soil P availability and improve phosphorus fertilizer use efficiency [pg. 18811, first col.]. Furthermore, Wang teaches a chelating effect on metallic medium and trace elements in the multiple metallic medium and trace element sources (e.g. poly-P fertilizers exhibit significant effects on mobilizing or activating soil recalcitrant P through chelating with soil metal ions such as Ca2+, Mg2+, Fe3+, and Al3+) [pg. 18811, first col.]. In regard to claim 2, Walker teaches the multiple metallic medium and trace element sources comprise calcium source, magnesium source, boron source, molybdenum source, iron source, zinc source, manganese source and copper source (e.g. NPKS in addition to micronutrients including zinc, copper, iron, manganese, boron, molybdenum and secondary nutrients calcium, magnesium and silicon [pg. 19, last para.]. In regard to claim 3, Walker teaches wherein the controlled release fertilizer contains components [pgs. 17-19; 21]: ppw Calculated as wt.% w/w % ammonium polyphosphate 100-300 7-32 phosphorous 0.5-15 nitrogen source 400-700 29-68 nitrogen 1-15 potassium source 150-450 11-44 potassium 0.5-12 calcium source 10-50 0.6-6.5 secondary nutrient 0.5-18 magnesium source 50-100 3-13 0.5-18 boron source 1-3 0.06-0.41 trace nutrient 0.01-2 molybdenum source 1-3 0.06-0.41 0.01-2 iron source 5-20 0.3-2.7 0.01-2 zinc source 0.5-1 0.03-0.14 0.01-2 manganese source 1.5-2 0.09-0.28 0.01-2 copper source 0.5-1 0.03-0.14 0.01-2 agglomerant 5-30 0.31-4 binder 1-10 The ranges calculated from the Walker reference overlap or lie inside the claimed ranges. With regard to the ranges of the nitrogen source claimed, because Walker recites the percentage of total nitrogen, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention that to achieve a total nitrogen content within the ranges disclosed by Walker would necessarily require a greater amount of “nitrogen source” as claimed (e.g. if urea is the nitrogen source, a nitrogen content would be between 13-31% which overlaps with the Walker range). In regard to claim 4, Walker teaches wherein the nitrogen source is ammonium nitrate phosphate (e.g. ammonium nitrate and monoammonium phosphate) [pg. 18], and the potassium source is potassium sulfate [pg. 19]. Claims 5-8 are rejected under 35 U.S.C. 103 as being unpatentable over Walker (WO-2022133548) in view of Wang et al. (ACS omega, 2021) as applied to claim 4 above, and further in view of Kopf et al. (US Patent Publication No. 2022/0332659). In regard to claims 5-8, Walker discloses NPKS in addition to micronutrients including zinc, copper, iron, manganese, boron, molybdenum and secondary nutrients calcium, magnesium and silicon [pg. 19, last para.] but does not explicitly disclose the suitable salts as claimed. Kopf et al. is directed to fertilizer granules based on inorganic salts [abstract]. The fertilizers described by Kopf may contain macronutrients [0092] and micronutrients [0096]. In regard to claim 5, Kopf teaches a calcium source as potassium calcium magnesium sulfate (e.g. polyhalite K2Ca2Mg(SO4)4.2H2O) [0095] and a magnesium source selected from a group consisting of magnesium sulfate, magnesium nitrate and magnesium chloride (e.g. suitable salts include magnesium sulfate, magnesium chloride) [0095]. In regard to claim 6, Kopf teaches a boron source (e.g. sodium borate or boric acid) [0096] and a molybdenum source (e.g. sodium molybdate or ammonium molybdate) [0096]. In regard to claim 7, Kopf teaches an iron source (e.g. iron EDTA chelates) and a zinc source (e.g. zinc sulfate) [0096]. In regard to claim 8, Kopf teaches a manganese source (e.g. manganese sulfate) and copper source (e.g. copper sulfate) [0096]. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to utilize the macronutrient and micronutrient components recited by Kopf. One of ordinary skill in the art would have been motivated to choose from well-known and predictable materials frequently used in the art when the general conditions of the claimed nutrient elements are disclosed. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to Jennifer A Smith whose telephone number is (571)270-3599. The examiner can normally be reached Monday - Friday 9:30am-6pm EST. 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, Amber R Orlando can be reached at (571) 270-3149. 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. /JENNIFER A SMITH/Primary Patent Examiner, Art Unit 1731 January 29, 2026
Read full office action

Prosecution Timeline

Apr 27, 2023
Application Filed
Jan 29, 2026
Non-Final Rejection — §103, §112 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

1-2
Expected OA Rounds
61%
Grant Probability
88%
With Interview (+26.3%)
3y 2m
Median Time to Grant
Low
PTA Risk
Based on 863 resolved cases by this examiner. Grant probability derived from career allow rate.

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