Prosecution Insights
Last updated: April 19, 2026
Application No. 17/601,533

POLYBUTYLENE TEREPHTHALATE THERMOFORMING PROCESS

Final Rejection §103
Filed
Oct 05, 2021
Examiner
NERANGIS, VICKEY M
Art Unit
1763
Tech Center
1700 — Chemical & Materials Engineering
Assignee
BASF Corporation
OA Round
6 (Final)
56%
Grant Probability
Moderate
7-8
OA Rounds
3y 1m
To Grant
85%
With Interview

Examiner Intelligence

Grants 56% of resolved cases
56%
Career Allow Rate
649 granted / 1152 resolved
-8.7% vs TC avg
Strong +28% interview lift
Without
With
+28.5%
Interview Lift
resolved cases with interview
Typical timeline
3y 1m
Avg Prosecution
69 currently pending
Career history
1221
Total Applications
across all art units

Statute-Specific Performance

§101
0.3%
-39.7% vs TC avg
§103
47.7%
+7.7% vs TC avg
§102
17.0%
-23.0% vs TC avg
§112
22.6%
-17.4% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1152 resolved cases

Office Action

§103
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 . Response to Amendment All outstanding rejections, except for those maintained below, are withdrawn in light of applicant’s amendment filed on 10/28/25. The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior office action. The new grounds of rejection set forth below are necessitated by applicant’s amendment filed on 10/28/2025. In particular, claim 26 is new. Thus, the following action is properly made final. Claim Rejections - 35 USC § 103 Claims 2-4, 6-8, 10-13, and 15, 17, 18, 21-26 are rejected under 35 U.S.C. 103 as being unpatentable over Mettlach (US 2011/0196098) in view of Smith (US 5,023,137). With respect to claims 2, 10, 15, 17, and 18, Mettlach discloses a polyester mixture for moldings and foils (films) comprising 30-98 wt % aromatic polyester that is preferably polybutylene terephthalate (paragraph 0018), 1-20 wt % semiaromatic polyester based on aliphatic and aromatic diacids and aliphatic dihydroxy compound having melting point of 60-170°C (paragraph 0093), and 0-60 wt % of other additives (abstract). The examples include polybutylene terephthalate and Ecoflex FBX 7011 semiaromatic polyester (paragraphs 0162, 0163, and 0165). Mettlach teaches that polyester mixtures comprising polybutylene terephthalate and an aliphatic-aromatic polyester provide improved flowability (i.e., processability) (paragraph 0009) as shown in Table 1 (paragraph 0168) where Example 2 with semiaromatic polyester has improved viscosity and flowability represented by MVR than Comp Example 1 which has no semiaromatic polyester. Improved flowability is indirectly related to necking upon elongation because there is less constraint on the softened or melt state. Mettlach teaches that the polyester mixture is used in molding to form sheets (paragraph 0169) by extrusion or injection molding (paragraphs 0149 and 0153) but fails to disclose that the polyester mixture is used in a thermoforming process. Smith discloses a polyester composition suitable for use in thermoforming dual-ovenable trays comprising polyethylene terephthalate (an aromatic polyester in the same class of polyesters as polybutylene terephthalate) (abstract) and teaches that polyesters are widely known to be thermoformed (col. 1, lines 34-64). Smith teaches that a sheet is formed from the polyethylene terephthalate composition, preheating the sheet until it softens above its Tg at mold temperature of 140-220°C (col. 7, lines 14-27), positioning over the mold and drawn into the shape, and heatsetting the formed sheet (col. 6, lines 53-68). Smith does not explicitly disclose a cooling step but one is necessarily present in order to handle the thermoformed articles at room temperature. Given that Mettlach teaches that a polyester mixture for use in molding articles has improved flowability due to the addition of the semiaromatic polyester and further given that aromatic polyesters are widely known to be thermformable as taught by Smith, it would have been obvious to one of ordinary skill in the art to utilize the polyester mixture having improved flowability of Mettlach as a suitable composition in a thermoforming process that is expected to have reduced necking compared to a polyester mixture with no semiaromatic polyester. With respect to claims 3, 4, 6, and 11, Mettlach teaches adding and fillers in an amount of up to 50 wt % (paragraph 0136) and an impact modifiers polymer in an amount of 1-20 wt % (paragraph 0095) such as one including ester of (meth)acrylic acid and a monomer comprising epoxy groups (paragraph 0096-0102) or glycidyl (meth)acrylate (i.e., epoxy modified (meth)acrylate) (paragraph 0119). With respect to claims 7 and 8, Mettlach teaches that the semiaromatic polyester is optionally derived from diols such as claimed c1, c2, c3, c4, c5, c6, d1, d2, and/or d3 (paragraphs 0063-0083). Therefore, it would have been obvious to one of ordinary skill in the art to utilize any of these compounds individually or as mixtures with BA and BB. With respect to claims 12 and 13, Mettlach does not require the addition of biodegradable homo- or copolyesters such as polylactide, polycaprolactone, PHA, and aliphatic polyesters vinyl copolymers derived from styrene or acrylic acid. With respect to claims 21 and 22, Smith does not require a step between extrusion and thermoforming. With respect to claim 23, Mettlach discloses a polyester mixture for moldings and foils (films) comprising 30-98 wt % aromatic polyester that is preferably polybutylene terephthalate (paragraph 0018), 1-20 wt % semiaromatic polyester based on aliphatic and aromatic diacids and aliphatic dihydroxy compound having melting point of 60-170°C (paragraph 0093), and 0-60 wt % of other additives (abstract). With respect to claims 24-26, comparative example 3 of Mettlach includes only polypolybutylene terephthalate (A1) and Ecoflex FBX 7011 semiaromatic polyester (C) as polymers. While this example is not the inventive example, it is considered to be representative of the prior art as a whole and not just limited to Mettlach’s invention. This formulation is a known prior art composition, e.g., see paragraph 0009 (WO 2004/078844). Given that Mettlach shows improved thermformability via reduced necking by adding a semiaromatic polyester to polybutylene terephthalate, it would have been obvious to one of ordinary skill in the art to thermoform a known composition as suitable for thermoforming as taught by Smith, though it is in a comparative example, which does not comprise polymers other than polybutylene terephthalate and semiaromatic polyester. Claim 5 is rejected under 35 U.S.C. 103 as being unpatentable over Mettlach (US 2011/0196098) in view of Smith (US 5,023,137) and further in view of Aoshima (JP 2008-222995). The discussion with respect to Mettlach and Smith in paragraph 5 above is incorporated here by reference. Mettlach fails to disclose the addition of 0.1-2 wt % styrene-acrylic acid-glycidyl methacrylate copolymer but Smith teaches a deep drawing procedure (col. 6, lines 63-64). Aoshima discloses a polybutylene terephthalate resin composition containing an epoxy group-containing acrylic-styrene polymer as a melt tension modifier to improve drawdown properties (paragraph 0006) in an amount of 0.5-7.0 parts by weight (paragraphs 0006-0007). Aoshima exemplifies epoxy group-containing acrylic-styrene polymer that is methyl methacrylate-glycidyl methacrylate-styrene copolymer (paragraph 0020). Given that Mettlach and Smith and Aoshima disclose drawn polybutylene terephthalate films and further given that Aoshima discloses adding an epoxy group-containing acrylic-styrene polymer as a melt tension modifier to improve drawdown properties, it would have been obvious to one of ordinary skill in the art to add the epoxy group-containing acrylic-styrene polymer such as methacrylate-glycidyl methacrylate-styrene copolymer to the thermoforming process taught by Mettlach and Smith. Response to Arguments Applicant's arguments filed 10/28/2025 have been fully considered but they are not persuasive. Specifically, applicant argues that flowability represented by melt flow rate is not related to necking deformation during thermoforming. In Table 1 of Mettlach, the comparison between comp Example 1 (not including semiaromatic polyester C) and Example 2 (the same except for the addition of 5 parts by weight semiaromatic polyester C) shows that Example 2 exhibits a higher MVR at 250°C, i.e., flowability, but also shows that the modulus of elasticity and yield stress of Example 2 are lower, i.e., more flexible. Both flowability and flexibility affect thermoforming stability at ambient conditions and at 250°C. Therefore, the method of thermoforming a polyester composition having improved flowability and flexibility would be expected to exhibit reduced necking. Also, in Tables 1 and 2, when comparing comp Example 3 (includes only PBT and semiaromatic polyester) with comp Example 4 (includes only PBT), comp Example 3 higher MVR at 250°C in combination with lower modulus of elasticity and yield stress. Therefore, Mettlach teaches that the semiaromatic polyester provides for improvements in flowability and flexibility, i.e, properties which would be expected to provide relatively improved necking during thermforming molding process. It is noted that the claims do not specify to what degree necking. Therefore, even the smallest reduction in necking that is suggested by Mettlach reads on claimed reduction in necking. Applicant argues that it is impermissible to rely on a comparative example in a 103 rejection. The examiner agrees that solely relying on a comparative example in other than a 102 rejection is usually improper. However, the examiner is relying on Mettlach’s comp Example 3 as representative of a prior art reference cited by Mettlach (WO 2004/078844) which discloses a polymer blend consisting of polybutylene terephthalate and semiaromatic polyester is a known prior art composition. In the 103 rejection set forth above, Smith teaches that it is well known to thermoforming terephthalic acid based polyester and therefore not limited to the inventive compositions of Mettlach. Rather, it would have been obvious to one of ordinary skill in the art that any of the terephthalic acid based polyesters of the prior art, including both inventive and comparative compositions taught by Mettlach, can be suitably thermoformed as taught by Smith. Also, Mettlach provides evidence that the semiaromatic polyester when added to PBT exhibits improved flowability and flexibility even without the addition of high branched polyester and/or polycarbonate. Therefore, Mettlach’s comp Example 3 would be expected to exhibit reduced necking during a thermoforming process. Applicant argues that Smith does not disclose a blend of polybutylene terephthalate and semiaromatic polyester and therefore should not be combined with Mettlach. While does not disclose all the features of the present claimed invention, it is used as teaching reference, and therefore, it is not necessary for this secondary reference to contain all the features of the presently claimed invention, In re Nievelt, 482 F.2d 965, 179 USPQ 224, 226 (CCPA 1973), In re Keller 624 F.2d 413, 208 USPQ 871, 881 (CCPA 1981). Rather this reference teaches a certain concept, and in combination with the primary reference, discloses the presently claimed invention. Specifically, it teaches that terephthalic acid-based polyesters are commonly used in thermoforming processes. 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 VICKEY NERANGIS whose telephone number is (571)272-2701. The examiner can normally be reached 8:30 am - 5:00 pm EST, Monday - Friday. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Joseph Del Sole can be reached at (571)272-1130. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /VICKEY NERANGIS/Primary Examiner, Art Unit 1763 vn
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Prosecution Timeline

Oct 05, 2021
Application Filed
May 14, 2024
Non-Final Rejection — §103
Jul 16, 2024
Applicant Interview (Telephonic)
Jul 16, 2024
Response Filed
Jul 16, 2024
Examiner Interview Summary
Sep 20, 2024
Final Rejection — §103
Oct 22, 2024
Response after Non-Final Action
Oct 28, 2024
Response after Non-Final Action
Nov 15, 2024
Request for Continued Examination
Nov 19, 2024
Response after Non-Final Action
Dec 31, 2024
Non-Final Rejection — §103
Feb 06, 2025
Response Filed
Apr 02, 2025
Final Rejection — §103
Jun 03, 2025
Applicant Interview (Telephonic)
Jun 03, 2025
Examiner Interview Summary
Jun 04, 2025
Response after Non-Final Action
Aug 04, 2025
Request for Continued Examination
Aug 05, 2025
Response after Non-Final Action
Aug 17, 2025
Non-Final Rejection — §103
Oct 28, 2025
Response Filed
Dec 16, 2025
Final Rejection — §103 (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

7-8
Expected OA Rounds
56%
Grant Probability
85%
With Interview (+28.5%)
3y 1m
Median Time to Grant
High
PTA Risk
Based on 1152 resolved cases by this examiner. Grant probability derived from career allow rate.

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