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 .
This Office action is in response to the amendment filed 7/21/2026. Claims 3-4, 9 and 16 are cancelled; and claim 17 is amended. Accordingly, claims 1-2, 5-8, 10-15 and 17-18 are currently pending in the application.
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
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.
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 1-2, 5-7, 10-15 and 17-18 are rejected under 35 U.S.C. 103 as being unpatentable over Garland et al (US 2015/0011717 A1) in view of Kiss et al (US 2009/0076214 A1).
Regarding claims 1 and 6, Garland et al disclose a process for producing high pressure polyethylene (HPPE). The process includes contacting ethylene, an optional polar comonomer in the presence of an initiator to a reaction system under polymerization conditions to form a reaction system effluent comprising a first polyethylene resin having a first concentration of unreacted monomer and directing reaction system effluent to a pressure separation unit operated at separation conditions thereby removing at least a portion of the unreacted monomer from the reaction system effluent (abstract). HPPE resin can have a density as low as about 0.9 g/cm3 (paragraph 0010) which reads on LDPE in present claim 1. High pressure polymerization system 1 (Fig. 1) can include an ethylene feed source 3 that supplies ethylene monomer to a first compressor 5 that pressurizes the ethylene to a pressure of about 150 to 200 bar. A second compressor 10 located downstream of, and in fluid communication with the first compressor 5, increases the pressure of the reactor feed to greater than or equal to about 3000 bar (paragraph 0026) which reads on delivering a monomer feedstock comprising ethylene monomer to a compressor system to produce a pressurized feedstock having a pressure of at least 2000 bar in present claim 1. The compressed reactor feed is introduced to a reactor 18. The reactor can include two or more initiator injection points to feed initiator to the reactor 18 (paragraph 0028) to produce a polymer in combination with unreacted monomer (i.e., reads on passing the pressurized feedstock to at least one free radical polymerization reactor to produce a reactor effluent comprising LDPE and unreacted ethylene monomer in present claim 1). The exiting mixture of polymer alone or in combination with unreacted monomer can pass through a high pressure let down valve 32 into a separation system that can include one or more high pressure separation (HPS) vessels (i.e., reads on first separation vessel in present claim 1) and one or more low pressure separation vessels (paragraph 0029) which reads on second and third separation vessel in present claim 1. The low pressure separation vessel can operate at a pressure of from 0.5 bar to 2.0 bar (paragraph 0031) which overlaps with the operating pressure of second separation vessel in present claim 1. Case law holds that when the range of instant claims and that disclosed in prior art overlap, a prima facie case of obviousness exists. See In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976). See MPEP § 2144.05. It is noted that no stripping agents are added upstream of the separation vessel.
Garland et al are silent with respect to third separation vessel having an operating pressure of less than or equal to 0.05 bar; amount of unreacted monomer in separation product comprising LDPE; and adding additives.
Regarding third separation vessel having an operating pressure of less than or equal to 0.05 bar, Kiss et al in the same field of endeavor teach that polymer rich phase may be transferred to one or more low pressure separators running at just above atmospheric pressure for a simple flash of light components, reactants or oligomers for producing a low volatile-containing polymer melt entering the finishing extruder. Separators located downstream in the process operate at lower pressure relative to separators located upstream (paragraph 0255). The monomer rich phase is separated and recycled while the polymer rich phase is fed to a coupled devolatilizer (paragraph 0256). The devolatilization is a separation process to separate remaining volatiles (paragraph 0259) and devolatilizing device operates under a strong vacuum (paragraph 0273). Therefore, in light of the teachings in Kiss et al, it would have been obvious to one skilled in art prior to the filing of present application to include the devolatilizing device operating at low pressures of less than 0.05 bar (i.e., under vacuum), in the process of Garland et al, to remove any remaining volatiles including the unreacted monomers, absent evidence to the contrary.
Regarding amount of unreacted monomer in separation product comprising LDPE, given that the process of present claims is obvious based on the disclosure in Garland et al combined with the teachings in Kiss et al and includes a process wherein the separators located downstream operate at lower pressure relative to separators located upstream as in present invention, one skilled in art prior to the filing of present application would have a reasonable basis to expect the separation product comprising LDPE to include less than or equal to 50 ppm of unreacted ethylene monomer as in present claim 1 or less than 30 ppm as in present claim 6, absent evidence to the contrary. Since PTO cannot conduct experiments, the burden of proof is shifted to the applicants to establish an unobviousness difference, see In re Best, 562 F.2d 1252, 195 USPQ 430 (CCPA 1977).
Regarding adding additives, Kiss et al teach that modifiers and additives may also be introduced either before or into the separator-blending vessel or downstream to it. However, a downstream introduction of these additives typically simplifies monomer recycle and is thus advantageous (paragraph 0150). Therefore, in light of the teachings in Kiss et al, it would have been obvious to one skilled in art prior to the filing of present application to add additives downstream including between the second and third separation vessel, for above mentioned advantages.
Regarding claim 2, Garland et al teach that purified polyethylene resin exiting the pressure separation unit is directed to a pelletization unit (paragraph 0005) which reads on pelletizing separation product without a subsequent purging step in present claim 2.
Regarding claim 5, Kiss et al teach that additives are added in amount of less than 1 wt% (paragraph 0087) which overlaps with the amount of additive in present claim 5.
Regarding claim 7, case law holds that differences in temperature will not support patentability of the subject matter encompassed by the prior art unless there is evidence indicating such temperature is critical. MPEP 2144.05. As such, temperature of the third separation vessel influences the removal of unreacted monomers by volatilizing and thus would be considered a result effective variable. Thus, it would have been obvious to one of ordinary skill in the art to have optimized the temperature to any range including 180 to 2600C through routine optimization.
Regarding claim 10, Kiss et al teach that there is a pressure letdown between the separators (paragraph 0151).
Regarding claims 11 and 12, Garland et al teach that high pressure polymerization system 1 (Fig. 1) can include an ethylene feed source 3 that supplies ethylene monomer to a first compressor 5 that pressurizes the ethylene to a pressure of about 150 to 200 bar. A second compressor 10 located downstream of, and in fluid communication with the first compressor 5, increases the pressure of the reactor feed to greater than or equal to about 3000 bar (paragraph 0026) which reads on compressor system comprises a primary compressor and secondary compressor in present claim 11 and pressure of the monomer feedstock to at least 200 bar prior to feeding to secondary compressor in present claim 12.
Regarding claim 13, Garland et al teach that reactor 18 can be a tubular or autoclave reactor (paragraph 0035).
Regarding claim 14, see figure 1, of Garland et al wherein there is a high pressure let down valve 32 located between the reactor and HPS (figure 1 and paragraph 0029) which reads on reactor effluent is passed to a letdown valve upstream of the separation system in present claim 14.
Regarding claim 15, Garland et al teach that HPPE resin can include polymer units derived from one or more polar monomers (paragraph 0019).
Regarding claims 17-18, examples of additives in Kiss et al include antioxidants, flame retardants, UV stabilizers, lubricating agents, and coloring agents (paragraph 0144).
Claim 8 is rejected under 35 U.S.C. 103 as being unpatentable over Garland et al (US 2015/0011717 A1) in view of Kiss et al (US 2009/0076214 A1) and Shin et al et al (US 2009/0076214 A1).
The discussion with respect to Garland et al and Kiss et al in paragraph 8 above is incorporated here by reference.
Garland et al and Kiss et al are silent with respect to operating pressure of the first separation vessel.
However, Shin et al disclose a method of recovering ethylene and vinyl comonomer that is capable of improving the rate of recovery of unreacted monomers. The method comprises polymerizing ethylene and vinyl based comonomer at a pressure of 1500 bar or more, a step of depressurizing the product obtained in the polymerization step including ethylene-vinyl based comonomer polymer, ethylene and comonomer (abstract). After the polymerization, the process of depressurizing to a pressure of 0.1 to 5 bar does not proceed all at once but is carried out sequentially undergoing the first depressurization step of reducing the pressure to 200 bar to 300 bar (i.e., reads on the operating pressure of first separation vessel in present claim 8), a second and third depressurizing step to 0.1 bar to 5 bar (paragraph 0017). The method for recovering in which the compression is progressed from respective pressures after separating them while lowering the pressure step by step reduces the cost required for the compression process, thus ensuring the economic efficiency of the process (paragraph 0018). Therefore, in light of the teachings in Shin et al, it would have been obvious to one skilled in art prior to the filing of present application, to use an operating pressure in the first separation vessel in overlapping ranges, in the process of Garland et al in view of Kiss et al independently, for above mentioned advantages.
Response to Arguments
The rejections under 35 U.S.C. 112(a) and 112(d) as set forth in paragraphs 5 and 7, of Office action mailed 5/13/2026, are withdrawn in view of amendments and/or applicant arguments that are persuasive.
Applicant's arguments with respect to rejections under 35 U.S.C. 103, filed 7/21/2026, have been fully considered but they are not persuasive. Specifically, applicant argues (A) Kiss teaches a final devolatizing device operating under strong vacuum that "use stripping agents such as water or nitrogen, to further reduce the volatile content of the polymer [0273]. While Garland is silent to the use of stripping agent, Garland in View of Kiss would teach a person of ordinary skill in the art to include a stripping agent to reduce unreacted ethylene monomer; and (B) not including a stripping agent upstream of third separation vessel provides the unexpected results of reduced unreacted ethylene monomer content compared to comparative examples including stripping agent.
With respect to (A), Kiss teaches “devolatilization is a separation process to separate remaining volatiles from the polymer, without resorting to older, inefficient processes such as steam stripping. The final devolatizing device may operate under a strong vacuum and may optionally use stripping agents such as water or nitrogen (paragraph 0273). Hence, it is clear the use of stripping agents is optional and is considered inefficient.
With respect to (B), in Table 1, none of the inventive examples can be compared to the comparative examples to see the impact of not adding stripping agent, since there are several variables. For example, IE 1 and CE A/CE B have the same amount of unreacted ethylene monomer before devolatilization but the pressure is varied. Similarly in Table 2, only IE 3 can be compared to CE D and CE E because of the similar operating temperatures. However, operating pressures are different. Hence, it is not clear which variable is being compared to obtain similar residual ethylene monomer in the final polymer (the inclusion/non-inclusion of stripping agent or differences in the pressure). Therefore, applicant argument of unexpected results is not convincing.
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.
Contact Information
Any inquiry concerning this communication or earlier communications from the examiner should be directed to KARUNA P REDDY whose telephone number is (571)272-6566. The examiner can normally be reached 8:30 AM to 5:00 PM M-F.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Arrie (Lanee) 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.
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/KARUNA P REDDY/Primary Examiner, Art Unit 1764
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