DETAILED ACTION
Notice of Pre-AIA or AIA Status
1. The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Status of the Claims
2. Claims 1-12, 14-21 are currently pending. Claims 16-21 have been withdrawn as being drawn to a non elected invention. Claims 1-12, 14-15 are currently under examination. This office action is the first office action on the merits of the claims.
Election/Restrictions
3. Claims 16-21 are withdrawn from further consideration pursuant to 37 CFR 1.142(b), as being drawn to a nonelected invention, there being no allowable generic or linking claim. Applicant timely traversed the restriction (election) requirement in the reply filed on 09/29/2025.
Applicant's election with traverse of Group I Claims 1-12 and 14-15 in the reply filed on 09/29/2025 is acknowledged. The traversal is on the ground(s) that the office has not show a serious burden would be required to examine all of the pending claims, and that a lack of unity of invention was not raised in the examination of the PCT application upon which this application is based. Thus all method and hydrogel claims were searched together in the PCT application. This is evidence that the claims have unity of invention and should be searched together. Further Claim 1 is amended to recite that the method is a 3D fabricating method, the plurality of multivalent cations is provided as a colorless salt and the heating step and cooling step is repeated 2 to 10 times, Claim 17 is amended to recited that he hydrogel is a 3D printed hydrogel, the plurality of multivalent cations is provided as a colourless salt and that the toughness of the hydrogel is at least 10 J/m3 and accordingly the present claims relate to a method of 3D fabricating a hydrogel and the 3d printed hydrogel thereof and thereby possess a special technical feature not taught or suggested in Fang. This is not found persuasive because showing a serious search burden is not a requirement of a lack of unity restriction, which requires instead that it be shown there is no special technical feature of the claim set. That the PCT application upon which this application is based did not indicate a lack of unity is not an indication that a lack of unity is not present only that the particular examiner did not raise the point of lack of unity. This is particularly the case as the amended indication of 3D fabrication of claim 1 is not the same as 3D printing indicated in claim 17. As such the lack of a special technical feature is shown by the rejection indicated below over Qin (CN 107603106-A; all citations refer to the english language machine translation which is provided) as is evidenced by Massey (US 2013/0142915 A1) which teaches the method of claim 1 and as such teaches the common technical feature of the claims and so there is no special technical feature of the claim set and so no unity among the claims.
The requirement is still deemed proper and is therefore made FINAL.
Claim Interpretation
4. Claim 1 includes the phrase “A method of 3D fabricating” which is given its broadest reasonable interpretation as the method must make a 3 dimensional object.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
5. Claims 1-12, 14-15 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Concerning claim 1 the claim recites “a colorless salt” which renders the claim indefinite as it is not clear if this indication of colorless means that the salt can be white, which can be considered to have no color, or if the salt must be transparent.
Additionally concerning claim 1 the claim recites “wherein step (b) and step (c) are repeated 2 to 10 times” which renders the claim indefinite as it is not clear if this means that the indicated steps are performed a total of 2 to 10 times or if this means that the steps are performed once and then repeated to give a total performed times of 3 to 11.
Also concerning claim 1 the claim recites “the plurality of multivalent cations” which does not have antecedent basis for this limitation in the claim. There is enough antecedent basis for “a plurality of multivalent ions”.
Concerning claim 3 the claim recites “wherein the plurality of charged monomers is a salt form of a plurality of monomer, the monomer selected from” which renders the claim indefinite as it is not clear what “the monomer” refers to and if it is the plurality of charged monomer or the plurality of monomer and so it is not clear what is present in the indicated method. Moreover Acrylamide is not know to have salts so it is not clear what this means in regard to what can be present in the polymerizing step.
Concerning claim 4 the claim recites “at a concentration of about 5 wt% to about 50 wt%” which renders the claim indefinite as it is not clear what this is based off of. Is this based off of the reactants that make the ion impregnated hydrogel? The composition which is polymerized in step (a) which could include solvent?
Concerning claims 10-12 the claims recite “the ion impregnated hydrogel( from step (a))” which renders the claims indefinite as it is not clear if the indication in parenthesis is required or merely an example.
Concerning claim 10 the claim recited “wherein the step of exposing (step b) crosslinks the ion impregnated hydrogel (from step (a)) via ionic interactions” which renders the claim indefinite as it is not clear if the indication in parenthesis of step b is required or exemplary.
Concerning claim 12 the claim recites “is heated by exposing the ion impregnated hydrogel or to microwave radiation for at least 15 sec” which renders the claim indefinite as it is not clear what the “or to” means.
Concerning claim 15 the claim recites “wherein the toughness of the hydrogel is increased by at least about 100%” which renders the claim indefinite as there is not antecedent basis for “the hydrogel” as claim 1 from which it depends indicates a tough hydrogel , formed from the method and a ion impregnated hydrogel which is formed in step (a) of the method and it is not clear which of these is being referred to. Moreover it is not clear what this toughness increase is measured against. Is it in regard to the hydrogel before and after all of the steps of (b) and (c)? Is it in regard to a hydrogel without the multivalent ions present? Moreover it is not clear what a toughness measurement is as there are multiple different types of toughness tests such as izod notched impact test and Charpy impact test and it is not clear what toughness test is being referred to by applicant. Applicants specification paragraph 0054 gives that toughness can be described as area under a stress strain curve. This is not sufficient to be considered to be definition of toughness but even this raises questions bout what the bounds of toughness are as this does not indicate under what conditions the stress strain curve is obtained. Is it under tension? Compression? Shear? Stress curves are known to be different with different strain rates so what conditions are the stress strain curve measured? Is a particular temperature used?
Claim Rejections - 35 USC § 102
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 the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
6. Claim(s) 1-7, 9-12, 14-15 is/are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Qin (CN 107603106-A; all citations refer to the english language machine translation which is provided) as is evidenced by Massey (US 2013/0142915 A1).
Concerning claim 1-2, 4-7, 14 Qin teaches a method of preparing an acrylamide polyvinyl alcohol acrylic acid calcium chloride composite hydrogel (paragraph 0002). This method includes dissolving acrylamide acrylic acid calcium chloride and polyvinyl alcohol in water to obtain a uniform mixture (paragraph 0012), add a crosslinking agent and an initiator to the mixed solution I (paragraph 0013), after vacuuming and defoaming the mixed liquid is sealed in a glass mold and the water bath is heated to 40-70 °C for 1-8 hours to obtain a certain shape of the hydrogel (paragraph 0014) after which the gel is frozen at -20°C for 12 hours and then thawed a room temperature for 8 hours and the freezing thawing cycle is repeated 3 times to obtain the acrylamide polyvinyl alcohol acrylic acid calcium chloride three network composite hydrogel (paragraph 0015). The thawing step would correspond to exposing the ion impregnated hydrogel to heat as it is exposed to a higher temperature than it had previously been at and the freezing would correspond to cooling the ion impregnated hydrogel.
The hydrogel is indicated to have calcium ions for divalent crosslinks by coordination with acrylic acid and improved mechanical properties because of the cross-linking present (paragraph 0019) in the hydrogel. This increase of mechanical properties would make the hydrogel a tough hydrogel and the presence of calcium as a divalent linker would indicate that the hydrogel is an ion impregnated hydrogel. The hydrogel is indicated to be crosslinked to form a three dimensional hydrogel network which can maintain the shape of the hydrogel (paragraph 0017) which indicates that the method is a method 3d fabricating a tough hydrogel. Acrylic acid is a known charged monomer particularly in water where the carboxylic acid group disassociates and acrylic acid includes a vinyl group and so would correspond to the claimed charged vinyl monomer.
Qin teaches a particular method that is performed by adding polyvinyl alcohol and deionized water into a flask and heating at 90°C for 2 hours to dissolve the polyvinyl alcohol to form a uniform solution and then cooled to room temperature (paragraph 0031). Then Acrylamide acrylic acid polyvinyl alcohol and calcium chloride where added to deionized water at a mass ratio of 4:2:1:0.2 to obtain a homogenous mixture where the concentration of acrylamide acrylic acid polyvinyl alcohol and calcium chloride is 23.07 wt% and then N,N’methylene bisacrylamide is added (paragraph 0032). The mixture is bubbled with argon for 0.5 hours and then ammonium persulfate and N,N,N’,N’-tetramethyleneethylene diamine is evenly mixed, after which the obtained solution is transferred to a glass mold, vacuumed, and ultrasonically treated sealed and incubated at 60°C for 6 hours (paragraph 0032). After the reaction is complete the water is coagulated and the gel is frozen at -20°C for 12 hours and then placed at room temperature to thaw for 8 hours and the freezing thawing process was repeated three times to form the composite hydrogel (paragraph 0032). Given that the total amount of components in the solution is indicated to be 23.07 wt% and the mass ratio is indicated to be 4:2:1:0.2, this would indicate that the amount of the acrylic acid charged monomer in the solution provided to the polymerization step is approximately 6.41 wt% which is within the claimed range of about 5wt% to about 50 wt%.
Qin is silent as to the plurality of multivalent cations is provided as a colourless salt.
Qin as is stated above teaches that calcium chloride is provided to the polymerization step in the form of a uniform solution. Calcium chloride is a salt that contains a multivalent cation of calcium with a valency of 2.
Massey provides evidence that CaCL2 added to water and dissolved produced a perfectly clear solution (paragraph 0104). This would provide evidence that the calcium chloride solution which uses water as a solvent would be a colorless salt.
As such since the form of the salt which is provided to the polymerizing step is colorless than the method indicated by Qin would include all of the claimed limitations and so teach the claimed method.
Concerning claim 3 Qin as evidenced by Massey teaches the method of claim 1 as is stated above.
Qin teaches that a solution of acrylamide acrylic acid calcium chloride and polyvinyl alcohol is provided to the polymerization step (paragraph 0032). Moreover Qin teaches that the calcium ion will coordinate with the carboxylic acid group on the acrylic acid (paragraph 0017). As such the solution which is provided would include at least some acrylic acid groups which are coordinated with the calcium ions present in solution and as such would be considered to be acrylic acid calcium salts. As such the plurality of charged monomer includes a salt form of acrylic acid and so meet the claimed limitations. It should also be note that the monomers present in the polymerization include acrylamide.
Concerning claim 9 Qin as evidenced by Massey teaches a particular method that is performed by adding polyvinyl alcohol and deionized water into a flask and heating at 90°C for 2 hours to dissolve the polyvinyl alcohol to form a uniform solution and then cooled to room temperature (paragraph 0031). Then Acrylamide acrylic acid polyvinyl alcohol and calcium chloride where added to deionized water at a mass ratio of 4:2:1:0.2 to obtain a homogenous mixture where the concentration of acrylamide acrylic acid polyvinyl alcohol and calcium chloride is 23.07 wt% and then N,N’methylene bisacrylamide is added (paragraph 0032). The mixture is bubbled with argon for 0.5 hours and then ammonium persulfate and N,N,N’,N’-tetramethyleneethylene diamine is evenly mixed, after which the obtained solution is transferred to a glass mold, vacuumed, and ultrasonically treated sealed and incubated at 60°C for 6 hours (paragraph 0032). After the reaction is complete the water is coagulated and the gel is frozen at -20°C for 12 hours and then placed at room temperature to thaw for 8 hours and the freezing thawing process was repeated three times to form the composite hydrogel (paragraph 0032). Given that the total amount of components in the solution is indicated to be 23.07 wt% and the mass ratio is indicated to be 4:2:1:0.2, this would indicate that the amount of the calcium chloride in the solution provided to the polymerization step is approximately 0.6408 wt% . Using the fact that the molar mass of Calcium chloride is approximately 110.98 g and that a liter of water is approximately 1000 g allows for the calculation of the molarity of the calcium chloride and therefore the molarity of the calcium ion. This results in a concentration of approximately 0.0577 mol/L which corresponds to 0.0577 M or 57.7 mM. This value is within the claimed range of about 10mM to about 2 M and as such the method of Qin would teach the claimed limitations.
Concerning claim 10 Qin as evidenced by Massey teaches a particular method that is performed by adding polyvinyl alcohol and deionized water into a flask and heating at 90°C for 2 hours to dissolve the polyvinyl alcohol to form a uniform solution and then cooled to room temperature (paragraph 0031). Then Acrylamide acrylic acid polyvinyl alcohol and calcium chloride were added to deionized water at a mass ratio of 4:2:1:0.2 to obtain a homogenous mixture where the concentration of acrylamide acrylic acid polyvinyl alcohol and calcium chloride is 23.07 wt% and then N,N’methylene bisacrylamide is added (paragraph 0032). The mixture is bubbled with argon for 0.5 hours and then ammonium persulfate and N,N,N’,N’-tetramethyleneethylene diamine is evenly mixed, after which the obtained solution is transferred to a glass mold, vacuumed, and ultrasonically treated sealed and incubated at 60°C for 6 hours (paragraph 0032). After the reaction is complete the water is coagulated and the gel is frozen at -20°C for 12 hours and then placed at room temperature to thaw for 8 hours and the freezing thawing process was repeated three times to form the composite hydrogel (paragraph 0032). It should be noted that the incubation at 60°C would expose the hydrogel which is formed in this step to the 60 °C temperature after it is formed, after which the ion impregnated hydrogel is frozen. As such the exposure to 60 °C as and after the hydrogel is formed would correspond to the claimed step b. Qin further teaches that the calcium ion will coordinate with the carboxylic acid group on the acrylic acid in order to form a divalent crosslinking (paragraph 0017). As such the ionic interaction which causes the divalent crosslinking through the calcium ion would be expected to form crosslinking at the step of exposure to 60 °C as the higher temperature would allow for greater mobility of ions in the ion impregnated hydrogel and Qin specifically states that the divalent crosslinking though calcium ions coordinating with acrylic acid will be present. It should be noted that the limitation of “the step of exposing (step(b)) crosslinking the ion impregnated hydrogen (from step (a)) via ionic interactions” is given its broadest reasonable interpretation that crosslinking must occur in step B but that it need not occur in every step B.
Concerning claim 11 Qin as evidenced by Massey teaches a particular method that is performed by adding polyvinyl alcohol and deionized water into a flask and heating at 90°C for 2 hours to dissolve the polyvinyl alcohol to form a uniform solution and then cooled to room temperature (paragraph 0031). Then Acrylamide acrylic acid polyvinyl alcohol and calcium chloride where added to deionized water at a mass ratio of 4:2:1:0.2 to obtain a homogenous mixture where the concentration of acrylamide acrylic acid polyvinyl alcohol and calcium chloride is 23.07 wt% and then N,N’methylene bisacrylamide is added (paragraph 0032). The mixture is bubbled with argon for 0.5 hours and then ammonium persulfate and N,N,N’,N’-tetramethyleneethylene diamine is evenly mixed, after which the obtained solution is transferred to a glass mold, vacuumed, and ultrasonically treated sealed and incubated at 60°C for 6 hours (paragraph 0032). After the reaction is complete the water is coagulated and the gel is frozen at -20°C for 12 hours and then placed at room temperature to thaw for 8 hours and the freezing thawing process was repeated three times to form the composite hydrogel (paragraph 0032). It should be noted that the incubation at 60°C would expose the hydrogel which is formed in this step to the 60 °C temperature as and after it is formed. This would correspond to the claimed “exposed to heat at a temperature of about 40°C to about 100°C” as is currently claimed. As such Qin would teach the claimed method.
Concerning claim 15 Qin teaches the method of claim 1 as is stated above.
Qin teaches that the example has a tensile strength of 0.310 MPa and an elongation at break of 445.12% (paragraph 0033) and teaches examples other hydrogels made by similar methods that have a tensile strength of 0.572 MPa and an elongation at break of 611.55% (paragraph 0041) or a tensile strength of 0.337 MPa and an elongation at break of 744.86%.
Qin further teaches that the hydrogel is a three network composite hydrogel where the copolymer of acrylic acid and polyvinyl alcohol interpenetrate, the acrylic acid coordinates with calcium ions to form divalent crosslinks, and a three dimensional network is formed by the polymerization of acrylamide acrylic acid and crosslinking agent (paragraph 0019). Linear molecules of polyvinyl alcohol are interspersed and microphase separation occurs during the freezing thawing process to form crosslinks (paragraph 0019). All of these crosslinking processes improve the mechanical properties of the obtained hydrogel, and therefor would be expected to improve the toughness of the hydrogel.
As is stated above Qin teaches the claimed method having each of the claimed steps and components, and indicates that there is an improvement of the mechanical properties of the hydrogel.
"[T]he discovery of a previously unappreciated property of a prior art composition, or of a scientific explanation for the prior art’s functioning, does not render the old composition patentably new to the discoverer." Atlas Powder Co. v. IRECO Inc., 190 F.3d 1342, 1347, 51 USPQ2d 1943, 1947 (Fed. Cir. 1999). Thus the claiming of a new use, new function or unknown property which is inherently present in the prior art does not necessarily make the claim patentable. In re Best, 562 F.2d 1252, 1254, 195 USPQ 430, 433 (CCPA 1977). See MPEP 2112.I.
There is no requirement that a person of ordinary skill in the art would have recognized the inherent disclosure at the relevant time, but only that the subject matter is in fact inherent in the prior art reference. Schering Corp. v. Geneva Pharm. Inc., 339 F.3d 1373, 1377, 67 USPQ2d 1664, 1668 (Fed. Cir. 2003). See MPEP 2112.II.
"[T]he PTO can require an applicant to prove that the prior art products do not necessarily or inherently possess the characteristics of his [or her] claimed product. Whether the rejection is based on ‘inherency’ under 35 U.S.C. 102, on ‘prima facie obviousness’ under 35 U.S.C. 103, jointly or alternatively, the burden of proof is the same." In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433-34 (CCPA 1977). See MPEP 2112.V.
Where the claimed and prior art products are identical or substantially identical in structure or composition, or are produced by identical or substantially identical processes, a prima facie case of either anticipation or obviousness has been established. In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433 (CCPA 1977). "When the PTO shows a sound basis for believing that the products of the applicant and the prior art are the same, the applicant has the burden of showing that they are not." In re Spada, 911 F.2d 705, 709, 15 USPQ2d 1655, 1658 (Fed. Cir. 1990). See MPEP 2112.01.I.
As such since Qin teaches the claimed method using the claimed materials and teaches the improvement of mechanical properties than the method of Qin would result in the claimed toughness and Qin would teach the claimed limitations.
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.
7. Claim(s) 1-11, 14-15 is/are rejected under 35 U.S.C. 103 as being unpatentable over Omidian (US 2003/0232895 A1) in view of Qin (CN 107603106-A; all citations refer to the english language machine translation which is provided) as is evidenced by Bergner (US 4,203,812).
Concerning claim 1-2, 5, 7-8, 14 Omidian teaches a method of making a hydrogel material with enhanced mechanical strength properties by i) combining at least one ethylenically unsaturated monomer and a multi-olefinic crosslinking agent to form an admixture, ii)subjecting the admixture to polymerization conditions to form a hydrogel composite iii) combing at least one strengthening agent with the admixture prior to or after performing step ii so the that the hydrogel composite contains the at least one strengthening agent and iv) subjecting the hydrogel composition containing strengthening agent to strengthening conditions effective to afford the hydrogel material having enhanced strength properties (paragraphs 0066-0070). The indication of improved mechanical properties would indicate that the hydrogel is a tough hydrogel and the use of a multiolefinic crosslinking agent would cause chemical crosslinking that would result in a 3D structure and so the method would be a method of 3D fabricating a tough hydrogel.
Particularly preferred monomers which can be used in the admixture include acrylamide, 2-hydroxyethyl (meth)acrylate, acrylic acid, inorganic and organic salts of acrylic acid diallyl dimethylammonium chloride potassium salt of 3-sulfopropyl acrylate and mixtures of these (paragraph 0072). Preferred multi olefinic crosslinking agent include N,N’-methylenebisacrylamide among others (paragraph 0073). Preferred polymer strengtheners include polyvinyl alcohol polymer among others (paragraph 0078). Other chemical strengthening agents include ionotropic gelation agents such as calcium chloride and aluminum chloride hexahydrate (paragraph 0081) which include multivalent cations. The strengthening conditions can entail contacting the hydrogel composite with chemical strengthening agents or alternatively subjecting the hydrogel composition to cryogellation conditions such as by applying a freeze-thaw cycle on Polyvinyl alcohol and the hydrogel composite (paragraph 0081). Polymerization is indicated to be initiated by any known applicable mechanism such as thermal polymerization using ammonium persulfate and oxidation reduction reactions such as using ammonium persulfate and tetramethylenylene diamine (paragraph 0083).
The strengtheners used are described as primary and secondary in terms of the final strength and elasticity they provide with primary approaches including cryogel approaches that use poly vinyl alcohol among others (paragraph 0090 and 0144-0147) and secondary approaches including ionotropically crosslinked non polysaccharides such as acrylic acid polyacrylic acid acrylamide and polyacrylamide (paragraph 0091). Concerning the cryogel approach using polyvinyl alcohol Omidan indicates that processing using multiple freeze thaw cycles help increase the strength of the Polyvinyl alcohol containing hydrogel (paragraph 0147).
Omidian does not specifically teach the polymerizing of a plurality of charged monomers in the presence of a plurality of multivalent ions in combination with repeated steps of exposing the ion impregnated hydrogel to heat and cooling the impregnated hydrogel, or that the plurality of multivalent cations is provided as a colorless salt. However as is stated above Omidian teaches that acrylic acid can be ionotropically crosslinked with multivalent ions, and that using polyvinyl alcohol as a strengthening agent can use multiple freeze thaw cycles to increase the mechanical strength of the hydrogel. Moreover, Omidian teaches that the method can use at least one strengthening agent in the composition and teaches that the strengthening agents can be added before polymerization.
Qin is drawn to hydrogels with improved mechanical properties and teaches a method that includes dissolving acrylamide acrylic acid calcium chloride and polyvinyl alcohol in water to obtain a uniform mixture (paragraph 0012), add a crosslinking agent and an initiator to the mixed solution I (paragraph 0013), after vacuuming and defoaming the mixed liquid is sealed in a glass mold and the water bath is heated to 40-70 °C for 1-8 hours to obtain a certain shape of the hydrogel (paragraph 0014) after which the gel is frozen at -20°C for 12 hours and then thawed a room temperature for 8 hours and the freezing thawing cycle is repeated 3 times to obtain the acrylamide polyvinyl alcohol acrylic acid calcium chloride three network composite hydrogel (paragraph 0015). The thawing step would correspond to exposing the ion impregnated hydrogel to heat as it is exposed to a higher temperature than it had previously been at and the freezing would correspond to cooling the ion impregnated hydrogel.
Bergner is drawn to solutions of aluminum chloride and provides evidence that aluminum chloride which is isolated from aqueous solution is colorless and when dissolved in water forms clear solutions (column 4 lines 25-35). This would indicate that aluminum chloride hydrate and alumnium chloride solution in water are both colorless salts.
It would have been obvious to one of ordinary skill in the art at the time of filling to alter the method of Omidian to use a combination of ionic and polyvinyl alcohol strengthening agents with the charged monomer of acrylic acid before polymerization and to use a freeze thaw cycle 4 times as taught in Qin because Omidan teaches that multiple strengthening agents can be used, that strengthening agents can be used before polymerization, and that polyvinyl alcohol uses multiple freeze thaw cycles to increase the strength of the hydrogel, and Qin teaches particular steps to use a combination of a ionic crosslinker, polyvinyl alcohol crosslinker, and a multiolefinic crosslinker and the particular amount of freeze thaw cycles that are useful in order to provide increased mechanical properties and to use aluminum chloride hexahydrate to give the claimed method using a colorless salt because Omidian teaches that aluminum chloride hexahydrate is a pererable ionotropic strengthening agent and Bergner provides evidence that this salt is colorless.
Concerning claim 3 Omidian teaches that preferred monomers which can be used in the hydrogel include acrylic acid and acrylic acid inorganic or organic salts (paragraph 0072).
It would have been obvious to one of ordinary skill in the art at the time of filling to use a salt of acrylic acid as the monomer of the method of Omidian in view of Qin as is evidenced by Bergner because Omidian teaches that salts of acrylic acid are preferable monomers to be used in the polymerization of the hydrogel.
Concerning claim 4 Qin further teaches a particular method that is performed by adding polyvinyl alcohol and deionized water into a flask and heating at 90°C for 2 hours to dissolve the polyvinyl alcohol to form a uniform solution and then cooled to room temperature (paragraph 0031). Then Acrylamide acrylic acid polyvinyl alcohol and calcium chloride where added to deionized water at a mass ratio of 4:2:1:0.2 to obtain a homogenous mixture where the concentration of acrylamide acrylic acid polyvinyl alcohol and calcium chloride is 23.07 wt% and then N,N’methylene bisacrylamide is added (paragraph 0032). The mixture is bubbled with argon for 0.5 hours and then ammonium persulfate and N,N,N’,N’-tetramethyleneethylene diamine is evenly mixed, after which the obtained solution is transferred to a glass mold, vacuumed, and ultrasonically treated sealed and incubated at 60°C for 6 hours (paragraph 0032). After the reaction is complete the water is coagulated and the gel is frozen at -20°C for 12 hours and then placed at room temperature to thaw for 8 hours and the freezing thawing process was repeated three times to form the composite hydrogel (paragraph 0032). Given that the total amount of components in the solution is indicated to be 23.07 wt% and the mass ratio is indicated to be 4:2:1:0.2, this would indicate that the amount of the acrylic acid charged monomer in the solution provided to the polymerization step is approximately 6.41 wt% which is within the claimed range of about 5 wt% to about 50 wt%.
It would have been obvious to one of ordinary skill in the art at the time of filling to alter the method of Omidian in view of Qin as is evidenced by Bergner to use the amounts of charged monomer of acrylic acid as is indicated in the method of Qin for the purpose of providing sufficient charged monomer that can be used to ionically crosslink the hydrogel.
Concerning claim 6 Omidian further teaches that preferable multiolefin crosslinkers which must be present in the method include N,N’ methylenebisacrylamide (paragraph 0073).
It would have been obvious to one of ordinary skill in the art at the time of filling to use N,N’ methylenebisacrylamide in the method of Omidian in view of Qin because Omidian teaches that N,N’ methylenebisacrylamide is a preferable crosslinker.
Concerning claim 9 Omidian as is stated above teaches that a secondary method of increasing the strength of the hydrogel is ionotropically crosslinked non polysaccharides such as acrylic acid polyacrylic acid acrylamide and polyacrylamide (paragraph 0091).
Omidian does not particularly teach the concentration of the multivalent ions.
Qin teaches a particular method that is performed by adding polyvinyl alcohol and deionized water into a flask and heating at 90°C for 2 hours to dissolve the polyvinyl alcohol to form a uniform solution and then cooled to room temperature (paragraph 0031). Then Acrylamide acrylic acid polyvinyl alcohol and calcium chloride where added to deionized water at a mass ratio of 4:2:1:0.2 to obtain a homogenous mixture where the concentration of acrylamide acrylic acid polyvinyl alcohol and calcium chloride is 23.07 wt% and then N,N’methylene bisacrylamide is added (paragraph 0032). The mixture is bubbled with argon for 0.5 hours and then ammonium persulfate and N,N,N’,N’-tetramethyleneethylene diamine is evenly mixed, after which the obtained solution is transferred to a glass mold, vacuumed, and ultrasonically treated sealed and incubated at 60°C for 6 hours (paragraph 0032). After the reaction is complete the water is coagulated and the gel is frozen at -20°C for 12 hours and then placed at room temperature to thaw for 8 hours and the freezing thawing process was repeated three times to form the composite hydrogel (paragraph 0032). Given that the total amount of components in the solution is indicated to be 23.07 wt% and the mass ratio is indicated to be 4:2:1:0.2, this would indicate that the amount of the calcium chloride in the solution provided to the polymerization step is approximately 0.6408 wt% . Using the fact that the molar mass of Calcium chloride is approximately 110.98 g and that a liter of water is approximately 1000 g allows for the calculation of the molarity of the calcium chloride and therefore the molarity of the calcium ion. This results in a concentration of approximately 0.0577 mol/L which corresponds to 0.0577 M or 57.7 mM. This value is within the claimed range of about 10mM to about 2 M .
It would have been obvious to one of ordinary skill in the art at the time of filling to alter the method of Omidian in view of Qin to include using the molar amount of the multivalent cation which crosslinks the hydrogel of Qin because this would teach a useful amount of the multivalent cation which would increase the strength of the hydrogel.
Concerning claims 10-11 Omidian as is stated above teaches a polymerization method which can include thermal polymerization by use of ammonium persulfate (paragraph 0083). Omidian also states that the ionic crosslinking of acrylic acid can be used as an approach to increase strength of the hydrogel (paragraph 0092)
Omidian does not particularly teach the temperature of an exposer to heat or that the step of exposing crosslinks the ion impregnated hydrogel.
Qin as evidenced by Massey teaches a particular method that is performed by adding polyvinyl alcohol and deionized water into a flask and heating at 90°C for 2 hours to dissolve the polyvinyl alcohol to form a uniform solution and then cooled to room temperature (paragraph 0031). Then Acrylamide acrylic acid polyvinyl alcohol and calcium chloride were added to deionized water at a mass ratio of 4:2:1:0.2 to obtain a homogenous mixture where the concentration of acrylamide acrylic acid polyvinyl alcohol and calcium chloride is 23.07 wt% and then N,N’methylene bisacrylamide is added (paragraph 0032). The mixture is bubbled with argon for 0.5 hours and then ammonium persulfate and N,N,N’,N’-tetramethyleneethylene diamine is evenly mixed, after which the obtained solution is transferred to a glass mold, vacuumed, and ultrasonically treated sealed and incubated at 60°C for 6 hours (paragraph 0032). After the reaction is complete the water is coagulated and the gel is frozen at -20°C for 12 hours and then placed at room temperature to thaw for 8 hours and the freezing thawing process was repeated three times to form the composite hydrogel (paragraph 0032). It should be noted that the incubation at 60°C would expose the hydrogel which is formed in this step to the 60 °C temperature after it is formed, after which the ion impregnated hydrogel is frozen. As such the exposure to 60 °C as and after the hydrogel is formed would correspond to the claimed step b. Qin further teaches that the calcium ion will coordinate with the carboxylic acid group on the acrylic acid in order to form a divalent crosslinking (paragraph 0017). As such the ionic interaction which causes the divalent crosslinking through the calcium ion would be expected to form crosslinking at the step of exposure to 60 °C as the higher temperature would allow for greater mobility of ions in the ion impregnated hydrogel and Qin specifically states that the divalent crosslinking though calcium ions coordinating with acrylic acid will be present.
It should be noted that the limitation of “the step of exposing (step(b)) crosslinking the ion impregnated hydrogen (from step (a)) via ionic interactions” is given its broadest reasonable interpretation that crosslinking must occur in step B but that it need not occur in every step B.
It would have been obvious to one of ordinary skill in the art at the time of filling to alter the method of Omidian in view of Qin to use the polymerization temperature of Qin to give the claimed method where this polymerization temperature exposes the ion impregnated hydrogel to heat and crosslinks the hydrogel via ionic interactions because Omidian teaches that thermal polymerization can be used and Qin teaches a specific polymerization temperature which is useful to give mechanically strengthened hydrogels.
Concerning claim 15 Omidian teaches that the hydrogels have improved elasticity and chemical strength properties (abstract) and teaches that cryogel methods using polyvinyl alcohol can be used as a primary strengthening method (paragraph 0090) and ionotropically crosslinking non polysaccharides can be used as a secondary approach to strengthening the hydrogel (paragraph 0091). Omidian further teaches that for a superporous hydrogel to be tough an optimized viscoelastic behavior is desirable, and at extremely high elastic behavior where the crosslink density of the hydrogel is very high, the polymer chains are not easily relaxed under certain stresses or loads, but at extremely viscous behavior in which the lowest crosslink density is applicable the polymer chains are fee to relax and display the behavior of a fluid under load (paragraph 0100). According an optimum amount of crosslinker concentration to permit reasonable chain stress relaxation is preferred (paragraph 0100).
It should be noted that Omidian teaches that the crosslinkers which can be present include a multi-olefinic crosslinking agent (paragraph 0067) and ionotropic crosslinking (paragraph 0091).
Qin specifically teaches that hydrogels made form its method include a chemical crosslinking network an ionic bond coordinated physical crosslinking network caused by the presence of the multivalent ion and a physical crosslinking of the polyvinyl alcohol forming crystalline microdomains thought the freezing thawing cycle process (paragraph 0026).
This would indicate that crosslinking depends on the amounts of the multivalent ion which crosslinks the acrylic acid, the multiolefin crosslinking agent, and the amount of polyvinyl alcohol.
It would have been obvious to one of ordinary skill in the art at the time of filling to optimize the amount of the multivalent ion which crosslinks the acrylic acid, the multiolefin crosslinking agent, and the amount of polyvinyl alcohol to provide optimal toughness which would provide the claimed toughness improvement because Omidian teaches that for a hydrogel to be tough that an optimum amount of crosslinker concentration is required to permit reasonable chain stress relaxation and each of the components causes a type of crosslinking.
Allowable Subject Matter
8. Claim 12 would be allowable if rewritten to overcome the rejection(s) under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), 2nd paragraph, set forth in this Office action and to include all of the limitations of the base claim and any intervening claims.
The following is a statement of reasons for the indication of allowable subject matter: None of the prior art of record teach or fairly suggest the claimed method which includes exposing the ion impregnated hydrogel to microwave radiation for at least 15 sec.
Conclusion
9. Claims 1-12, 14-15 are rejected. Claims 12 is allowable over the prior art of record but is rejected under 112.
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/DAVID L MILLER/Examiner, Art Unit 1763
/JOSEPH S DEL SOLE/Supervisory Patent Examiner, Art Unit 1763