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 Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(d):
(d) REFERENCE IN DEPENDENT FORMS.—Subject to subsection (e), a claim in dependent form shall contain a reference to a claim previously set forth and then specify a further limitation of the subject matter claimed. A claim in dependent form shall be construed to incorporate by reference all the limitations of the claim to which it refers.
The following is a quotation of pre-AIA 35 U.S.C. 112, fourth paragraph:
Subject to the following paragraph [i.e., the fifth paragraph of pre-AIA 35 U.S.C. 112], a claim in dependent form shall contain a reference to a claim previously set forth and then specify a further limitation of the subject matter claimed. A claim in dependent form shall be construed to incorporate by reference all the limitations of the claim to which it refers.
Claim 4 is rejected under 35 U.S.C. 112(d) or pre-AIA 35 U.S.C. 112, 4th paragraph, as being of improper dependent form for failing to further limit the subject matter of the claim upon which it depends, or for failing to include all the limitations of the claim upon which it depends. Claim 1 recites” wherein the total time of the surface crosslinking (S3) is 45 minutes to 75 minutes.” Claim 4 recites “The method of claim 1, wherein the total time for the surface crosslinking (S3) is 45 minutes to 75 minutes” which is the same total time range of claim 1 from which it depends. Applicant may cancel the claim(s), amend the claim(s) to place the claim(s) in proper dependent form, rewrite the claim(s) in independent form, or present a sufficient showing that the dependent claim(s) complies with the statutory requirements.
Claim Rejections - 35 USC § 103
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) 1-6 and 8-11 is/are rejected under 35 U.S.C. 103 as being unpatentable over Yoon et al. (US 2019/0126240) in view of Lee et al. (US 2017/0189575) and in further view of Won (US 2014/0058048).
As to claim 1, Yoon et al. discloses a process for forming a superabsorbent polymer (see abstract) comprising forming a water-containing gel polymer by crosslinking-polymerizing an acrylic acid based monomer having acidic groups that is neutralized, in the presence of an internal crosslinking agent (see 0043-0045).; obtaining a base polymer powder by drying, pulverizing, and classifying the water containing gel polymer (see 0133-0135); and preparing superabsorbent polymer particles, on which a surface-crosslinked layer is formed by performing heat treatment of the base powder in the presence of a surface crosslinking agent (see 0136, 0140).
Yoon et al. teaches the surface cross-linking reaction is carried out by heating the powder from 160C-170 C to 180-200 for 10-60 mins, and heating at 180-200C for 20-60 mins (see 0140).
Yoon et al. fails to explicitly state where a difference (T2-T1) between temperature T2 and temperature T1 is 10C to 20C, wherein the temperature T1 is a temperature at a point when 25% - 40% of a total time of the surface crosslinking has passed and the temperature T2 is a temperature at a time point when 70% to 100% of the total time of the surface crosslinking has passed, and the total time of surface crosslinking is 45 minutes to 75 minutes or tha the surface crosslinking agent is included in an amount of 1,000 ppmw to 5000 ppmw with respect to the base polymer powder as required by claim 1.
Lee et al. discloses a process for forming a superabsorbent polymer by providing an acrylic acid based monomer having acidic groups, that is neutralized, in the presence of an internal crosslinking agent; polymerizing the monomer to form a water containing gel polymer; drying, pulverizing, classifying the polymer; and providing a surface crosslinked layer over the base polymer by using a crosslinking agent and heat treating (see 0060-0066 and 0104-0107).
Lee et al. does teach performing surface crosslinking using a staged heat treatment profile where the temperature is raised from 160C to a target temperature of about 185C over an initial time period, followed by maintaining the temperature at about 185C for a subsequent time period (see Example 1, Table 1). In Example 1, the total surface crosslinking time is 60 mins, including 30 mins for raising the temperature from 160C to 185C and 30 minutes to hold the temperature at 185C. The temperature at approximately 25% to 40% of the total surface crosslinking time (T1) (i.e., about 15-24 mins) is about 172 – 180C, and the temperature at approximately 80 to 100% of the total surface crosslinking time (T2) (i.e., about 42 – 60 mins) is 185C. Lee et al. teaches a temperature difference T2-T1 in the range of approximately 5 to 13C which overlaps the claimed range. It has been established that 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).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to adjust the heating rate to within the claimed range through routine experimentation to optimize the physical properties of the polymer since Lee et al. teaches the surface crosslinking conditions controls the physical properties of the superabsorbent polymer (see 0107).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the process of Yoon et al. to include the heating process taught by Lee et al. One would have been motivated to do so since both are directed to forming superabsorbent particles formed by forming a surface crosslinked layer through heat treatment. Yoon et al. discloses a general teaching of performing a heat treatment with temperature and time ranges for surface crosslinking, whereas Lee et al. discloses a specific operable heating profile for forming the surface crosslinked layer. Accordingly, combining the teachings of Yoon et al. and Lee et al. would have been a predictable use of prior art elements according to their established functions to achieve a surface-crosslinked superabsorbent polymer having optimized physical properties.
Won et al. discloses a method for forming a superabsorbent polymer formed form a water-containing gel polymer that is formed into a powder by drying, pulverizing, and classifying; and then a surface crosslinked layer is formed on the powder in the presence of a surface crosslinking agent by heat treating (see abstract, 0025-0026, 0041-44, 0052-53, and 0057). Won et al. states the amount of agent used can be controlled according to the kind of surface cross-linking agent, the characteristics of the powder, or the reaction conditions (see 0049). Won et al. further discloses the surface crosslinking agent is provided 0.05 to 2 parts by weight per 100 parts by weight of milled polymer (500 ppm – 20,000 ppm) (see 0049) which overlaps the claimed range. It has been established that when 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).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to apply the surface crosslinking agent amount taught by Won et al. to the process of Yoon modified by Lee et al. in order to control the degree of surface crosslinking and optimize the physical properties of the superabsorbent polymer. One would have been motivated to do so since both references are directed to forming superabsorbent polymers by surface crosslinking and Won et al. discloses operable amounts of agent that are within the claimed range in order to achieve desired absorbency properties.
As to claim 2, Yoon et al. modified by Lee et al. discloses the temperature at about 30 – 40% of the surface crosslinking time (T1) (i.e., about 18-24 mins) is about 175- 180 C, and the temperature at approximately 90-100% (about 54-60 mins) of the total crosslinking time (T2) is 185C. The temperature difference is 5-10C which overlaps the claimed range. It has been established that 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).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to adjust the heating rate to within the claimed range through routine experimentation to optimize the physical properties of the polymer, since Lee et al. teaches the surface crosslinking conditions controls the physical properties of the superabsorbent polymer (see 0107).
As to claim 3, Yoon et al. modified by Lee et al. teaches a target temperature of 185C (see Table 1, Example 1 of Lee et al).
As to claims 4 and 5, Yoon et al. modified by Lee et al. teaches the total time of 60 mins (see Table 1, Example 1 of Lee et al.).
As to claim 6, the surface crosslinking agent used 1,3-propanediol (see 0153 of Yoon et al.).
As to claims 8 and 11, the CRC of the superabsorbent polymer is 41.1 g/g (see 0161, Table 2, Example 2 of Yoon et al.).
As to claim 9, the AUP is 22.5 g/g (see Yoon et al. Table 2, Example 2).
As to claim 10, Yoon et al. teaches a CRC of 41.1 g/g and an AUP of 22.5 g/g which equates to a EFFC of 31.8 g/g ( see Table 2, Example 2).
Response to Arguments
Applicant's arguments filed 04/08/2026 have been fully considered but they are not persuasive. Applicant argues that the cited references do not teach the claimed conditions and that controlling the temperature difference at specific points of 30-40% and 90-100% of the total surface crosslinking time results in a CRD of 40 g/g or greater with reduced variation. Claim 1 does not require T1 and T2 specifically at 30 – 40% and 90-100%. Rather, amended claim 1 recites broader ranges of 25-40% and 70-100%, respectively. Lee’s disclosed surface crosslinking profile produces a temperature difference overlapping the claimed 10-20C range at time points encompassed by those broader ranges. Applicant’s reliance upon a CRC of at least 40 g/g also does not establish patentability of claim 1. A CR of at least 40 g/g is not recited as a limitation of claim 1. Moreover, Yoon reports a CRC of 41.1 g/g in Table 2, Example 2. Thus, attaining a CRC of at least 40 g/g was known in the prior art.
The amendment requiring 1,000 – 5,000 ppw does not overcome the rejection because Won expressly reaches a broader surface crosslinking agent amount encompassing the range and teaches selection of the amount according to polymer characteristics and reaction conditions.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Nam et al. (US 20190100629 – cited in IDS) discloses a superabsorbent polymer that is prepared by forming a water-containing gel polymer by crosslinking polymerizing an acrylic acid-based monomer having acidic groups; obtaining a base polymer powder by drying, pulverizing, and classifying the water containing gel polymer; and forming a surface-crosslinked layer through heat treating in the presence of a surface crosslinking agent (see Example 1). Nam et al. further teaches the surface crosslinking is performed by heating from 20C to 185C over 20 minutes followed by 40 minutes at 185 C (total surface crosslinking time of 60 minutes). This would equate to T1 of about 168.5C at 30% of the time, thereby having a T2 – T1 of 16.5C. Nam et al. further states the CRC of 41.1 g/g and the use of about 1,400ppmw or crosslinking agent (see Example 1, Table 1, and Table 2).
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.
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/CACHET I. PROCTOR/
Examiner
Art Unit 1712
/CACHET I PROCTOR/ Primary Examiner, Art Unit 1712
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