Prosecution Insights
Last updated: April 19, 2026
Application No. 18/050,740

Glass Compositions, Fiberizable Glass Compositions, and Glass Fibers Made Therefrom

Final Rejection §103
Filed
Oct 28, 2022
Examiner
BROOKS, KREGG T
Art Unit
1764
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Electric Glass Fiber America LLC
OA Round
4 (Final)
56%
Grant Probability
Moderate
5-6
OA Rounds
3y 0m
To Grant
58%
With Interview

Examiner Intelligence

Grants 56% of resolved cases
56%
Career Allow Rate
395 granted / 701 resolved
-8.7% vs TC avg
Minimal +2% lift
Without
With
+2.0%
Interview Lift
resolved cases with interview
Typical timeline
3y 0m
Avg Prosecution
72 currently pending
Career history
773
Total Applications
across all art units

Statute-Specific Performance

§101
0.3%
-39.7% vs TC avg
§103
46.8%
+6.8% vs TC avg
§102
18.2%
-21.8% vs TC avg
§112
23.1%
-16.9% vs TC avg
Black line = Tech Center average estimate • Based on career data from 701 resolved cases

Office Action

§103
DETAILED ACTION Applicant’s amendment dated 5 March 2026 is hereby acknowledged. Claims 1, 2, 4, and 6-20 as amended are pending. All outstanding objections and rejections made in the previous Office Action, and not repeated below, are hereby withdrawn. The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior office action. New grounds of rejection set forth below are necessitated by applicant’s amendment filed on 5 March 2026. In particular, claim 1 now requires a range of TiO2. For this reason, the present action is properly made final. Claim Rejections - 35 USC § 103 Claim(s) 1, 2, 4, 6-12, and 15-20 are rejected under 35 U.S.C. 103 as being unpatentable over WO 2021/138394 A1 (“Korwin-Edson”). As to claim 1, Korwin-Edson teaches a glass composition for forming fibers (abstract). Korwin-Edson teaches SIO2 from 57 to 62 wt %, which is within the recited range, 7 to 9 wt % CaO, which is within the recited range, 8 to 12.5 wt % MgO, which is within the recited range (abstract). Korwin-Edson teaches the glass composition includes 0.4 to 1.0 wt % LI2O, which is within the recited range. Korwin-Edson teaches TiO2 ranging from 0.2 to 1.5 wt % (abstract), which substantially overlaps the recited range, in particular 0.5 to 0.7 wt % (para. 00062), which is within the recited range. Korwin-Edson teaches the composition is substantially free of B2O3 (para. 00066), which meets the recited range. Korwin-Edson also teaches less than 1.0 wt % of rare earth oxides such as Y2O3, which meets the recited range (para. 00069). Korwin-Edson does not explicitly discuss the combined content of MgO and CaO. However, the separately taught amounts of each total to a range of 15 to 21.5 wt %, which substantially overlaps the recited range. Furthermore, the exemplary embodiments include 7.9 to 9 wt % CaO (para. 00059), and 10.5 to 12.0 wt % (para. 00058), which totals to 18.4 to 21 wt %, which is within the recited range. Korwin-Edson does not exemplify the recited amount of Al2O3. However, Korwin-Edson teaches that the amount of Al2O3 ranges from 19 to 25 wt % (abstract, para. 00057), which overlaps the recited range. Moreover, the use of Al2O3 according to Korwin-Edson in the recited range provides for 1.22 to 1.35 as the ratio of Al2O3 to the exemplary amounts of MgO and CaO combined. Korwin-Edson teaches the amount of alumina is chosen to provide high modulus without excessively increasing crystallization (para. 00057). As such, the modification of Korwin-Edson, including having Al2O3 content, and the ratio of Al2O3 to (MgO+CaO) is an obvious modification suggested by Korwin-Edson. As to claim 2, the amount of MgO and CaO content taught by Korwin-Edson (8.0=12.5 wt % MgO and 7-9 wt % CaO) necessarily requires that the ratio of CaO/MgO is less than 1.5. As to claim 4, Korwin-Edson teaches the composition includes Na2O in exemplary embodiments of 0.05 to 0.1 wt %, and K2O of 0.04 to 0.2 % by weight (para. 0064), and thus Korwin-Edson suggests exemplary embodiments of less than 0.5 wt % (see also, Table 2, examples 6-10, having total of less than 0.5 wt %). As to claim 6, Korwin-Edson teaches glass fibers formed from the glass composition (para. 00077). As to claim 7, Korwin-Edson teaches the recited elastic (Young’s) modulus in the recited range (para. 00073). As to claim 8, Korwin-Edson teaches a delta (actual fiber drawing temperature over liquidus) of over 60 degrees C (para. 00050), and as such, Korwin-Edson teaches its compositions can be formed with such property. As to claim 9, Korwin-Edson teaches liquidus temperature in the recited range (para. 00048). As to claim 10, Korwin-Edson does not discuss the melting temperature. However, given that Korwin-Edson suggests a glass fiber of the recited composition, that such resulting fibers would have the recited melting temperature. As to claim 11, Korwin-Edson does not discuss the specific modulus measurement as recited. However, given that Korwin-Edson suggests a glass fiber of the recited composition, that such resulting fibers would have the recited specific modulus. As to claim 12, Korwin-Edson teaches forming fiber strands (para. 00079). As to claim 15, Korwin-Edson teaches a fabric of glass fibers (abstract). As to claim 16, Korwin-Edson teaches that chopped fiber glass strands may be formed (para. 0002). As to claim 17, Korwin-Edson teaches a composite product of a polymeric matrix, thus polymer material, and plurality of glass fibers (para. 00034). As to claim 18, Korwin-Edson teaches the use of woven fabrics of glass fibers in plastics (polymers) (para. 00081). As to claim 19, Korwin-Edson teaches the polymer of the composite material may be thermoplastic or thermosetting (para. 00082). As to claim 20, Korwin-Edson teaches various articles, including wind blades, formed from the glass fibers (para. 00081). Claim(s) 13 and 14 are rejected under 35 U.S.C. 103 as being unpatentable over WO 2021/138394 A1 (“Korwin-Edson”) in view of WO 2016/179134 A1 (“Li”). The discussion of Korwin-Edson with respect to claim 6 is incorporated by reference. Korwin-Edson teaches forming glass fibers, but does not discuss rovings or yarns. Li teaches similar glass fiber forming composition, and teaches that glass fiber strands can be formed into yarns and rovings (p. 13), and as such, yarns and rovings are obvious end products of glass fibers as taught by Li. Response to Arguments Applicant’s arguments with respect to claim(s) 1, 2, 4, and 6-20 have been considered but are moot because the new ground of rejection does not rely on any combination of references applied in the prior rejection of record for any teaching or matter specifically challenged in the argument. Conclusion Applicant's amendment necessitated the 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. Any inquiry concerning this communication or earlier communications from the examiner should be directed to KREGG T BROOKS whose telephone number is (313)446-4888. The examiner can normally be reached Monday to Friday 9 am to 5:30 pm. 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, Arrie Reuther can be reached at (571)270-7026. 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. /KREGG T BROOKS/Primary Examiner, Art Unit 1764
Read full office action

Prosecution Timeline

Oct 28, 2022
Application Filed
May 08, 2025
Non-Final Rejection — §103
Jul 16, 2025
Response Filed
Aug 19, 2025
Final Rejection — §103
Nov 18, 2025
Response after Non-Final Action
Nov 24, 2025
Request for Continued Examination
Nov 27, 2025
Response after Non-Final Action
Dec 03, 2025
Non-Final Rejection — §103
Mar 05, 2026
Response Filed
Mar 27, 2026
Final Rejection — §103 (current)

Precedent Cases

Applications granted by this same examiner with similar technology

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FIBROUS MATERIAL IMPREGNATED WITH REACTIVE THERMOPLASTIC PREPOLYMER
2y 5m to grant Granted Apr 14, 2026
Patent 12590187
POLYMER COMPOSITE CAPABLE OF BEING QUICKLY DISSOLVED OR DISPERSED IN AQUEOUS SOLVENT AND PREPARATION METHOD AND APPLICATION THEREOF
2y 5m to grant Granted Mar 31, 2026
Patent 12590207
EPOXY COMPOSITION COMPRISING A BIO-BASED EPOXY COMPOUND
2y 5m to grant Granted Mar 31, 2026
Patent 12570778
ETHYLENE INTERPOLYMERS CATALYZED USING MIXED HOMOGENEOUS CATALYST FORMULATIONS
2y 5m to grant Granted Mar 10, 2026
Patent 12565031
STAINABLE MELAMINE LAMINATE PRODUCTS, COMPOSITIONS, AND METHODS OF MANUFACTURE
2y 5m to grant Granted Mar 03, 2026
Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

5-6
Expected OA Rounds
56%
Grant Probability
58%
With Interview (+2.0%)
3y 0m
Median Time to Grant
High
PTA Risk
Based on 701 resolved cases by this examiner. Grant probability derived from career allow rate.

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