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 .
Claim Status
Claims 1 and 8 were amended and claims 4-6 were canceled in the response filed 5/6/2026. Claims 1-3 and 7-15 are pending.
Withdrawn Claim Objections and Rejections
The amendments filed on 5/6/2026 are persuasive to overcome the objection and 35 USC 112(b) rejection of record on p. 2-3 of the OA dated 2/10/2026. Therefore, the objection and rejection are withdrawn.
The terminal disclaimer filed on 5/6/2026 disclaiming the terminal portion of any patent granted on this application which would extend beyond the expiration date of the US patent of co-pending application number 18/259792 has been reviewed and is accepted. The terminal disclaimer has been recorded. Therefore, the non-statutory double patenting rejection of record on p. 10-13 of the OA dated 2/10/2026 is moot.
Claim Rejections - 35 USC § 103
Claims 4-6 were canceled and their limitations were incorporated into claim 1. The rejections of record on p. 4-13 of the OA dated 2/10/2026 are modified to reflect this amendment. 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(s) 1-3, 7-11, and 13-15 is/are rejected under 35 U.S.C. 103 as being unpatentable over Yamasaki (US 2019/0292304, published on 6/26/2019, of record) in view of Osamu (US 3549504, published on 12/22/1970, of record).
Applicant claims a method for preparing an isocyanate compound comprising
A reaction step of reacting a salt of an amine compound with phosgene in the presence of a solvent to obtain a reaction product containing an isocyanate compound;
A degassing step of removing a gas phase from the reaction product;
A desolvation step of removing a solvent from the reaction product from which the gas phase has been removed;
A low boiling material-removing step of removing low boiling materials from the reaction product from which the solvent has been removed, and
A high boiling material-removing step of removing high boiling materials from the reaction product from which the low boiling materials have been removed;
Wherein the low boiling material-removing step is progressed in a distillation column to which a reboiler is connected to the bottom of the column and overheated inert gas is supplied to the bottom of the distillation column through the reboiler.
Yamasaki teaches a process for producing xylylene diisocyanate comprising reacting an aliphatic xylylenediamine (XDA, o, m, and/or p-see claims 9-11 and 13) hydrochloride salt (HCl, claim 14) with phosgene (carbonyl chloride) in an inert solvent, including aromatic hydrocarbons and esters (claim 15) to produce the corresponding xylylene isocyanates. See [0052-0084-steps a and b] and the following Fig. 1:
PNG
media_image1.png
538
1062
media_image1.png
Greyscale
.
Thus, step A of Yamasaki corresponds to the formation of the XDA·HCl salt and step B corresponds to the instantly claimed “reaction” step. Yamasaki then teaches a step C comprising a degassing step (41) to remove a gas phase (45) from the product and a desolvation step (51) to remove the solvent (55) from the reaction product from which the gas phase has been removed (42). See [0085-0090]. Yamasaki teaches that the degassed and desolvated reaction mixture (52) is fed to a tar-removal unit (61) and then passed via line (63) to a low-boiling removal tower (71) to remove low boiling impurities (74) to produce reaction stream (76) from the bottom of the column in a step d. See [0091-0101]. Bottoms stream (76) is fed to rectification column (81), wherein high boiling impurities are removed vial line (86) from the bottom of the column and providing purified xylylene diisocyanate (XDI) distillate product from the top of the column via line (84). See [0102-0109]. Figure 1 is fully defined with respect to the process in [0110-0173]. Therefore, Yamasaki teaches all of the steps recited in instant claim 1. Yamasaki further teaches that the temperature of the mixture at any point in the process should not exceed 190°C to prevent by-product formation and optimal conversion, and preferably falls within the range of 110-180°C. This temperature range overlaps with that of claim 1 regarding the temperature of each of the steps in the process being held at 165°C or less. See [0071, 0096-0097, 0104-0105] and MPEP 2144.05.
Further regarding the low boiling material-removing step in column (71), Yamasaki teaches that the column is equipped with a reboiler (78) to heat and re-circulate a portion of the bottoms product (76) back to the bottom of the column (71) via line (77). Yamasaki teaches that the reboiler (78) regulates the internal temperature of the low-boiling removal tower (71) and can use the “above-described” heat exchanger. See [0160-0162 and heat exchanger in 0139]. Yamasaki teaches that column (71) preferably has a column bottom temperature between 130 to 200°C, a column top temperature between 90-160°C and a column-top pressure between 0.05 – 3 kPa (0.375 – 22.5 torr). See [0096-0098].
Yamasaki does not explicitly teach that overheated (see p. 17, first paragraph of the specification as filed) inert gas is supplied to the bottom of the distillation column through the reboiler.
Osamu teaches a method for the purification of organic polyisocyanates, including xylylenediisocyanate, by fractional distillation in the presence of an inert gas or superheated vapor of an organic solvent. See abstract. In col. 1, lines 38-53, Osamu teaches: “An organic polyisocyanate, when produced by reacting the corresponding amine with phosgene, inevitably contains various byproducts having relatively low boiling points. This makes it necessary to submit the product mixture to a further purification process. Organic polyisocyanates, as is well known, have relatively high boiling points and are very unstable when heated. Heretofore, for the purpose of purifying the materials having high boiling point and which are susceptible to deterioration upon heating, a vacuum distillation method has usually been employed. However, in this method, the material to be purified is eventually subjected to a comparatively high temperature due to a remarkable rising of temperature necessarily caused around the bottom of distillation column by pressure drop. Therefore, organic polyisocyanates cannot be safely purified by this method.”
Osamu overcomes the issue by subjecting a mixture of an organic polyisocyanate and light (boiling) impurities to fractionation (distillation) by allowing the crude organic polyisocyanate to contact an inert gas in a fractionation column under such conditions that the pressure at the top of the fractionation column is lower than 200 mm Hg (torr) and the feed rate (C) of the inert gas satisfies equation (I). See col. 2, line 3 to col. 3, line 64. Figure 1 teaches an embodiment wherein an inert gas is used as the inert feed and Figure 2 teaches an embodiment wherein a superheated vapor of an organic solvent is used as the inert feed. See col. 2, lines 53-57.
Osamu teaches that the crude organic polyisocyanates may be treated by the present method in the form of the phosgenation products without any preparatory treatment, though removal of the high-boiling constituents is preferred. See col. 3, lines 15-21. The purification of XDI is exemplified in example 3 (Fig. 1) and in col. 8-14 (Fig. 2). Osamu teaches that the superheated solvent can comprise aliphatic hydrocarbons having 2 to 11 carbon atoms (claim 3). See col. 10, lines 18-40 and example D, including Table in col. 13-14. Osamu also teaches that the inert gas can be methane (CH4, a C1 hydrocarbon). See col. 3, lines 22-27. Osamu teaches that the superheated solvent/inert gas is heated to a temperature of between 100 to 210°C, depending on the polyisocyanate, with a temperature in the range of 100-170°C for XDI. This temperature range overlaps with all of the temperature limitations set forth in claim 1, wherein the inert gas is at 150-160°C and each of the steps and the bottom of the distillation column in the low-boiling material removing step is 165°C or less. See claim 8; example D in col. 13-14; col. 3, lines 50-60; and col. 10, lines 48-53 including xylylenediisocyanate. Also see MPEP 2144.05. The pressure of the bottom of the column (PB) is within the range of 5 to 200 mm Hg (torr), preferably 50 to 200 mmHg (torr), wherein both ranges overlap with the range of claim 1 of 50 torr or less. See col. 2, lines 3-4 and col. 3, lines 65-67. Also see MPEP 2144.05. Osamu teaches that the reboiler is a jacked vessel type reboiler equipped with a gas feed (sparger) ring which is fed from a heater (claims 2 and 7). See example 1 (Fig. 1) and example A in col. 11 (Fig. 2). Osamu teaches that the fractionating (distillation) apparatus can include columns with internal trays (baffles) (claim 8). See col. 3, lines 28-35.
It would have been prima facie obvious to combine the teachings of Yamasaki and Osamu to arrive at the instantly claimed process with a reasonable expectation of success before the effective filing date of the instant invention. A person of ordinary skill would have been motivated to feed an overheated inert gas stream to the reboiler in the process of Yamasaki because Osamu teaches that such a modification is known to prevent pressure drop during the distillation of the same polyisocyanate system (XDI) at similar temperatures and pressures. Therefore, including the overheated inert gas of Osamu in the process of Yamasaki will predictably increase the efficiency of the XDI production process by eliminating deleterious pressure drop in the low-boiling point removal distillation step. Also see MPEP 2143(I)(A).
Claim(s) 12 is/are rejected under 35 U.S.C. 103 as being unpatentable over Yamasaki (US 20190292304, published on 6/26/2019, of record) in view of Osamu (US 3549504, published on 12/22/1970, of record), as applied to claims 1-3, 7-11, and 13-15 above and further in view of Wang (“Facile Synthesis of Reductively Degradable Biopolymers Using Cystamine Diisocyanate as a Coupling Agent” Biomacromolecules, 2016, 17, p. 882, of record).
The Applicant claims a method wherein the amine compound is a sulfur-containing aliphatic amine selected from those among claim 12. Neither Yamasaki nor Osamu explicitly teach or suggest the use of the claimed amines.
Wang is directed toward the synthesis of biopolymers using cystamine diisocyanate (CDI) as a coupling agent. See abstract. Wang teaches that CDI is obtained from the corresponding amine hydrochloride (CDH) with triphosgene (BTC):
PNG
media_image2.png
112
814
media_image2.png
Greyscale
. See p. 885. CDH corresponds to the HCl salt of “bis(aminoethyl)disulfide”. Wang teaches that CDI provides facile access to reductively degradable biopolymers via condensation polymerization with various diols. See abstract.
It would have been prima facie obvious to combine the teachings of Yamasaki, Osamu, and Wang to arrive at the instantly claimed process with a reasonable expectation of success before the effective filing date of the instant invention. A person of ordinary skill would have been motivated to employ bis(aminoethyl)disulfide as a reactant in the process of Yamasaki and Osamu because Wang teaches that the isocyanate derived therefrom (CDI) has utility in biopolymer formation and can be made by an analogous process. Therefore, replacing one known amine with another known amine that can produce a valuable polymerization intermediate in a known and predictable process is prima facie obvious. Also see MPEP 2143(I)(B).
Response to Arguments on p. 10-13 of the Response filed 5/6/2026
Applicant argues that amended claim 1 recites a specific combination of process parameters for the purification of isocyanate compounds including:
1. supplying inert gas overheated to 150-160°C to the bottom of the distillation column through the reboiler (previously claim 4 and p. 17, first paragraph of the specification as filed);
2. maintaining each step of the process at a temperature of 165°C or less (previously claim 5); and
3. maintaining a distillation column bottom temperature bottom of 165°C or less and bottom pressure of 50 torr or less (previously claim 6).
Applicant argues Osamu does not teach steps 1-3 because “Osamu merely discloses lowering the boiling point by reducing partial pressure using inert gas”. Applicant argues that Osamu does not teach the claimed ranges, which are critical to the process because they prevent the thermal degradation of the isocyanate while simultaneously managing the hydraulic stability of the column. Applicant argues that Osamu teaches using inert gas primarily to lower the boiling point by reducing partial pressure wherein in the present application the overheated inert gas and specific pressure/temperature constraints are used to reduce the difference in hydraulic parameters between the top and bottom of the column. Applicant argues that the specifically claimed parameters ensures stable reflux formation under very low-pressure conditions, which is not a technical problem recognized by Yamasaki or Osamu. Applicant argues that the claimed limitations cannot be arrived it by routine optimization and that the rejection is based on impermissible hindsight.
The Applicant’s arguments have been fully considered but are not persuasive. Regarding the temperature limitations of claim 1, as indicated in the rejection:
“Yamasaki further teaches that the temperature of the mixture at any point in the process should not exceed 190°C to prevent by-product formation and optimal conversion, and preferably falls within the range of 110-180°C. This temperature range overlaps with that of claim 1 regarding the temperature of each of the steps in the process being held at 165°C or less. See [0071, 0096-0097, 0104-0105] and MPEP 2144.05.
…
Osamu teaches that the superheated solvent/inert gas is heated to a temperature of between 100 to 210°C, depending on the polyisocyanate, with a temperature in the range of 100-170°C for XDI. This temperature range overlaps with all of the temperature limitations set forth in claim 1, wherein the inert gas is at 150-160°C and each of the steps and the bottom of the distillation column in the low-boiling material removing step is 165°C or less. See claim 8; example D in col. 13-14; col. 3, lines 50-60; and col. 10, lines 48-53 including xylylenediisocyanate. Also see MPEP 2144.05. The pressure of the bottom of the column (PB) is within the range of 5 to 200 mm Hg (torr), preferably 50 to 200 mmHg (torr), wherein both ranges overlap with the range of claim 1 of 50 torr or less. See col. 2, lines 3-4 and col. 3, lines 65-67. Also see MPEP 2144.05.”
Therefore, the Office respectfully disagrees with the Applicant’s assertions that Yamasaki and Osamu do not teach the claimed temperature and pressure ranges. Further, both Yamasaki and Osamu teach the temperature limitations with particular respect to the formation of XDI, which is the same reaction exemplified in the examples of the specification as filed. See p. 20-25. Osamu in particular teaches that the upper limit of the temperature during the reaction steps is 170°C, which is only a 5 degree difference (+3% difference) from the upper limit of 165°C as claimed, while Yamasaki teaches an upper limit of 180°C. Therefore, both Yamasaki and Osamu provide significant guidance and motivation to the skilled artisan to stay within the claimed temperature ranges to prevent degradation of the desired XDI product. Also see MPEP 2144.05 regarding the obviousness of ranges.
In response to applicant's argument that the examiner's conclusion of obviousness is based upon improper hindsight reasoning, it must be recognized that any judgment on obviousness is in a sense necessarily a reconstruction based upon hindsight reasoning. But so long as it takes into account only knowledge which was within the level of ordinary skill at the time the claimed invention was made, and does not include knowledge gleaned only from the applicant's disclosure, such a reconstruction is proper. See In re McLaughlin, 443 F.2d 1392, 170 USPQ 209 (CCPA 1971).
Regarding the argument that Osamu only teaches adding the superheated inert gas to lower the boiling point by reducing partial pressure using inert gas as opposed to improving hydraulic properties in the distillation column, Osamu explicitly teaches that:
“XDI, as is well known, has a high boiling point (161°C at 10 mm. Hg) and is so unstable to heating that it is polymerized by heating to temperature higher than 170°C. The boiling points of the above-mentioned impurities are very near to that of XDI and moreover, the boiling point of impurity (I) which is produced in a greater amount than any other impurities is closest to that of XDI.
In purifying the crude XDI, therefore, the most important problem to be solved is how to eliminate effectively the impurities (I) to (III), and especially impurity (I).
Heretofore, for the purpose of removing these im- purities, a vacuum distillation method has been applied.
In this method, however, the objective compound to be purified is eventually subjected to a comparatively high temperature since a remarkable raising of temperature Sue to pressure drop inevitably occurs near the bottom of a distillation column. In other words, in this method, the employment of a fractionation column having several trays is required because of the little difference in boiling points between the impurities and XDI. Incidentally, the pressure drop amounts to considerable mm. Hg near the bottom of the column, whereby XDI is subjected to heating at about 180-200° C.
Therefore, by this method, XDI cannot satisfactorily be purified. For the purpose of solving this problem, many attempts to minimize the pressure drop in distillation column have been made. However, none of them has satisfactorily solved the problem.
The present invention is based on the disclosure that purification of crude XDI by fractionation can easily be completed without any bad effect on XDI itself at a low temperature with the use of hitherto-employed fractionation column such as tray column and packed column by selecting specific fractionation conditions.
The present method has been perfected on the basis of this discovery, and comprises subjecting crude XDI to fractionation by allowing the crude XDI to contact in a fractionation column with the superheated vapor of an organic solvent having a boiling point of from -20° C.
to 150° C. at a pressure of 200 mm. Hg. The organic solvent is exemplified by aliphatic hydrocarbon having 2 to 11 carbon atoms, alicyclic hydrocarbon having 5 to 8 carbon atoms, aromatic hydrocarbon, halogenated aliphatic hydrocarbon having 1 to 6 carbon atoms, or halogenated benzene. The crude XDI and solvent vapor are contacted under such conditions that the pressure at the top of the column is maintained at 5 to 200 mm. Hg and the temperature at the bottom of the column is maintained at not higher than 170° C.
According to this aspect of the present invention, the pressure drop at the bottom of fractionation column can effectively be improved, and therefore crude XDI can easily and satisfactorily be purified by fraction with the use of simple apparatus such as tray column and packed column, accompanied with no degradation of XDI itself due to the heating.
The object of the aspect of the present invention is to provide a novel method for purification by fractionation of crude XDI including impurities having boiling points extremely close to that of XDI, that is to say, to provide a novel method for eliminating these impurities as light cuts from the crude XDI.
Another object of this aspect of the invention is to provide pure XDI substantially free from impurities in a high yield by simple procedure.”
See col. 9, lines 4-70.
Therefore, Osamu appears to teach that the inclusion of the superheated inert gas in the distillation column accomplishes the same goal as that argued by the Applicant. “Hydraulic parameters” are only vaguely defined and discussed in the specification as filed, but it would appear that eliminating pressure drop in the distillation column (as is done is Osamu using the superheated inert gas in combination with the claimed pressure and temperature limitations) would qualify as improving the hydraulic parameters in the column. Osamu clearly considers the temperature of the superheated inert gas and the temperature and pressure in the column are critical to the success of the disclosed purification, and all of these values overlap very closely with those claimed. Further, Osamu also teaches that the quality and yield of the XDI will predictably decrease if the superheated inert gas is not included in the distillation column and if temperature in the column rises about the degradation temperature of the XDI (recited as 170°C). Therefore, the Office respectfully disagrees with the Applicant’s characterization of the teachings of Osamu. The Office maintains that the disclosure of Osamu, when applied to Yamasaki, would reasonably lead the skilled artisan to the claimed process with a reasonable expectation of success. Also see MPEP 2144.05 and MPEP 2143(I)(A).
Regarding the rejection over claim 12, the Applicant further argues that Wang does not cure the deficiencies of Osamu and Yamasaki. However, this is not persuasive for the reasons discussed above.
Conclusion
THIS ACTION IS MADE FINAL. 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 AMY C BONAPARTE whose telephone number is (571)272-7307. The examiner can normally be reached 11-7.
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, Scarlett Goon can be reached at 571-270-5241. 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.
/AMY C BONAPARTE/Primary Examiner, Art Unit 1692
Prosecution Insights