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 § 103
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.
Claim(s) 1-6 and 9 is/are rejected under 35 U.S.C. 103 as being unpatentable over Lee et al. (US 2017/0189575).
As to claim 1, Lee 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 0060-0063).; obtaining a base polymer powder by drying, pulverizing, and classifying the water containing gel polymer (see 0066); 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 0104-0107).
Lee 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 as required by claim 1.
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 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 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) and teaches times within the claimed range.
As to claim 2, 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, Lee discloses a target temperature of 185C (see Example 1, Table 1).
As to claims 4-5, Lee et al. teaches a total time of 60 mins (see Example 1 Table 1).
As to claim 6, the surface crosslinking agents are 1,3-propanediol and propylene glycol (see 0144).
As to claim 9, Lee et al. teaches the AUP is 25 g/g (see Example 1 of Table 2- measured at 0.7 psi see 0031).
Claim(s) 7 is/are rejected under 35 U.S.C. 103 as being unpatentable over Lee et al. (US 2017/0189575) as applied to claim 1 above in view of Won et al. (US 2014/0058048).
The teachings of Lee et al. as applied to claim 1 are as stated above.
Lee et al. discloses the use of a surface crosslinking agent but fails to teach including 1,000 ppmw to 5,000 ppmw of the surface crosslinking agent with respect to the base polymer as required by claim 7.
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 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.
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).
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 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. disclose a general teaching of performing a heat treatment with temperature and time ranges for surface crosslinking, whereas Lee et al. disclose 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.
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).
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Cachet I Proctor whose telephone number is (571)272-0691. The examiner can normally be reached Monday-Friday 7-3 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, Michael Cleveland can be reached at 571-272-1418. 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.
/CACHET I. PROCTOR/
Examiner
Art Unit 1715
/CACHET I PROCTOR/ Primary Examiner, Art Unit 1712
Prosecution Insights