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 .
Detailed Action
This office action is in response to applicant’s communication filed on 12/29/24.
Claims 16-35 are pending in this application and are being examined in this Office Action. The paragraph numbers for applicant’s specification herein refers to the paragraph numbers in applicant’s PGPub: US 2024294558.
Priority
The applicant claims benefit as follows:
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Objections
Claims 16 and 28 are objected to because of the following informalities:
Claim 16 is objected to because of the following informalities. Step (b) recites "using at least one Brønsted acid, removing, any solid constituents present." The comma after "removing" is extraneous and confusing. Claim 16 also labels its steps "(a)," "(b)" and "(c)" but refers back to them as "step a)" and "step b)." The labels should be used consistently.
Claim 28 is objected to because it recites "adding a fresh amount of alkoxysiloxane continuously or portionwise to a distillation bottoms." The article "a" should be removed.
The abstract of the disclosure is objected to because it is not a concise explanation of the invention, but it repeats the claim limitation. The abstract also begins with the phrase "The present invention provides," which should be avoided. See MPEP § 608.01(b). A corrected abstract of the disclosure is required and must be presented on a separate sheet, apart from any other text.
The specification is objected to because of the following informalities: Paragraphs [0091] and [0103] equate stearyl alcohol with hexadecanol. Stearyl alcohol is octadecanol, a C18 alcohol. Hexadecanol is cetyl alcohol, a C16 alcohol. Paragraph [0091] states a preference for a fatty alcohol "having a carbon number of C16 (preferably stearyl alcohol=hexadecanol)." Paragraph [0103] states that Example 1 used "15 g of stearyl alcohol (hexadecanol)." The two names cannot both be right. Applicant should clarify which alcohol was used.Appropriate correction is required.
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.
Claims 16-35 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 regards as the invention.
Claim 16 is indefinite because step (a) recites that the reaction mixture is created "with heating but without either the use of inert solvents which are water-insoluble but form azeotropes with water and/or without the use of further dehydrating agents."
The word "either" is confusing since it sets up a choice between two things and is normally closed by "or." Here it is closed by "and/or," and the word "without" is then repeated. The wording can be read two ways: 1. the process must leave out both the azeotrope-forming solvents and the dehydrating agents OR 2. the process must leave out only one of the two. Thus the two readings have different scope. The metes and bounds of step (a) are therefore unclear.
Claim 20 is indefinite because it recites an alcohol "selected from the group consisting of: methanol, ethanol, 1-propanol, isopropanol, 1-butanol, 2-butanol, isobutanol, pentanol, hexanol, heptanol, octanol, nonanol and/or decanol and/or the isomers thereof."
The phrase "consisting of" makes the group closed. The phrase "and/or" is open. The two are inconsistent. The correct Markush language is "selected from the group consisting of A, B and C".
Claim 25 is indefinite because it recites "wherein step (b) comprises a solvent selected from the group consisting of: alkanes, alkylaromatics, alcohols, hexamethylcyclotrisiloxane (D3), octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5) and dodecamethylcyclohexasiloxane (D6)."
Step (b) is a process step. A process step does not comprise a solvent. It is unclear whether the claim requires a solvent to be added during step (b), or requires only that a solvent be present during step (b).
Claim 28 is indefinite because it recites "adding a fresh amount of alkoxysiloxane continuously or portionwise to a distillation bottoms and discontinuously thereby restarting or continuing the formation of siloxane cycles."
The claim recites adding the fresh alkoxysiloxane "continuously" and also "discontinuously." A single addition cannot be both.
Appropriate correction is required. The dependent claims are rejected as depending from a rejected claim.
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 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 of this title, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 16-23 and 25-32 are rejected under 35 U.S.C. 103 as being unpatentable over Oku et al. ("Monomer recycling for vulcanized silicone rubbers in the form of cyclosiloxane monomers. Role of acid buffers," Polymer 2002, 43, 7289-7293, in applicant’s IDS filed 4/7/24) ("Oku" herein), in view of Petrus et al. ("Solvothermal Alcoholysis Method for Recycling High-Consistency Silicone Rubber Waste," Macromolecules 2021, 54, 2449-2465) ("Petrus" herein), further in view of Voronkov et al. ("Investigation in the Field of Alkoxysilanes. XIV. Cleavage of Organosiloxanes by Alcohols as a Method of Synthesizing Organoalkoxysilanes," Zh. Obshch. Khim. 1959, 29, pages 1501-1507, in applicant’s IDS filed 4/7/24) ("Voronkov" herein), and further in view of Vu et al. ("Back-to-cyclic-monomers: chemical recycling of silicone wastes using a [polydentate ligand-potassium silanolate] complex," ChemRxiv, posted January 4, 2023, in applicant’s IDS filed 4/7/24) (also see the supporting information) ("Vu" herein).
Determination of the Scope and Content of the Prior Art
(MPEP §2141.01)
Oku teaches a process for recycling waste silicone to siloxane cycles. Oku pulverizes vulcanized silicone rubber into pieces of about 1 mm and heats the pieces with KOH. The base breaks Si-O bonds of the main chain, and cyclosiloxane monomers are then formed by back-biting and end-biting of the potassium silanolate. The monomers recovered are D3, D4, D5 and D6. (Oku, abstract; page 7290, section 2.2 and Scheme 2; page 7291, Table 1)
Oku teaches running the depolymerization without solvent. Silicone rubber and KOH are stirred for 1 hour at 160° C., the temperature is raised to 170° C., an acid is added, and the mixture is then distilled at 170° C. and 30 mm Hg for 2 hours to collect the monomers. Oku teaches that using a solvent is energetically undesirable because the solvent must be removed before the monomers can be recovered. (Oku, page 7289; page 7290, section 2.2)
Oku teaches adding an acid to the basic reaction mixture after the depolymerization is over and before the mixture is distilled. The acid neutralizes the potassium silanolates and keeps the silanolate concentration low. Without added acid the yield is 46 percent. With KH2PO4 the yield is 83 percent, with the monopotassium salt of terephthalic acid 84 percent, and with citric acid, an organic acid, 64 percent. (Oku, abstract; page 7292, section 3.2 and Table 2)
Oku teaches that the amount of base controls the yield. The yield first rises and then falls as KOH is increased. Oku ran molar ratios of KOH to Si-O unit from 0.028 to 0.13 and found the best yield of about 65 percent at a ratio of 0.08. On a mass basis these ratios are about 2.1 to 9.8 percent of KOH on the silicone. (Oku, page 7291, Table 1 and Figure 1; page 7292, Table 2)
Oku also teaches running the same KOH depolymerization in toluene, an alkylaromatic, and then distilling the toluene off together with the monomers. (Oku, page 7290, section 2.2; page 7291, Table 1)
Petrus teaches the chemical recycling of post-consumer high-consistency silicone rubber waste by alcoholysis with fatty alcohols. The products are liquid alkoxysiloxanes R(OSiMe2)xOR, where x is 1, 2, 3 or 4, together with alkoxy-terminated oligomers Pm. The alcohols used are n-octanol, n-nonanol, n-decanol and n-dodecanol. (Petrus, abstract; page 2455, Scheme 3; page 2459)
Petrus teaches that the alcoholysis is run with no solvent and with no dehydrating agent. The shredded rubber and the alcohol are placed in the reactor and heated. The water formed in the reaction is not removed. (Petrus, page 2455; page 2464, "Silicone Rubber Alcoholysis Procedure")
Petrus teaches alkali metal catalysts, namely the lithium, sodium and potassium aryloxides [Li6(MesalO)6], [Na6(MesalO)6] and [K6(MesalO)6], used at 2 mol percent of metal at 200 to 220° C. for 2 hours. These gave 83 to 95 percent conversion of the silicone rubber to the alkoxysilane derivatives P1-P4. Petrus further teaches that the alcoholysis of siloxanes is conventionally carried out with alcohols in combination with KOH, KOH and amines, or Na(OEt) and amines, that is, with sodium ethoxide. (Petrus, page 2456; page 2458, Figure 13)
Petrus teaches that the reaction is run in a sealed steel high-pressure reactor with a PTFE-lined vessel, heated from 180 to 240° C., so that the pressure in the reactor is above atmospheric. Petrus teaches that alcohols with shorter main chains have lower boiling points, exert a higher pressure in the reactor, and give a higher conversion of the silicone rubber. (Petrus, page 2455; page 2459; page 2464)
Petrus teaches that the amount of alcohol controls the conversion. Petrus ran (OSiMe2) to ROH ratios of 1 to 2 through 1 to 8. At a ratio of 1 to 2 the conversion to P1 was 15 percent, and raising the alcohol four-fold raised that conversion to 24 percent. (Petrus, page 2456 and Figure 9)
Petrus teaches that a white solid residue is present at the lower reaction temperatures and is separated from the liquid product. Petrus further teaches removing the excess n-octanol from the liquid product by distillation at 100° C. and 10 mbar. (Petrus, page 2454, Figure 5; page 2455; page 2460, "Materials and Methods")
Voronkov teaches the cleavage of organosiloxanes by alcohols under basic conditions to give organoalkoxysilanes. Linear, branched or cyclic organosiloxanes are heated with primary or secondary alcohols in the presence of 1 to 10 mole percent of a hydroxide or an alcoholate of an alkali metal, and the corresponding organoalkoxysilanes are formed in yields of up to 70 percent. Voronkov teaches that under the reaction conditions the alkali metal hydroxides are converted into the alcoholates by the scheme MOH + ROH = MOR + HOH. In one worked example the base is metallic sodium dissolved in n-butyl alcohol, that is, sodium n-butoxide. (Voronkov, page 1501 and footnote; page 1505)
Voronkov teaches that the siloxanes cleaved in this way include hexamethylcyclotrisiloxane, the octamethylsiloxanes, and a high-molecular linear polydimethylsiloxane of molecular weight 200,000 to 400,000. The alcohols used contain 4 to 12 carbon atoms. Voronkov teaches that the yields of the alkoxysilanes remained approximately the same for all of these polydimethylsiloxanes. Voronkov further teaches that the cleavage may also be accomplished with methyl alcohol. (Voronkov, page 1501 footnote; page 1502)
Voronkov teaches worked examples that use no inert solvent and no dehydrating agent. In one, 14.8 g of octamethylcyclotetrasiloxane, 52.9 g of n-amyl alcohol and 0.56 g of powdered KOH were boiled under a reflux condenser fitted with a water trap, giving 67 percent of dimethyl-n-amoxysilane. In another, 60.0 g of hexamethyldisiloxane, 44.1 g of n-amyl alcohol and 1.0 g of KOH were boiled with no solvent. The second example uses 73.5 percent by mass of alcohol on siloxane. Voronkov states that one of the reagents was always used in considerable excess and that in some syntheses the siloxane was the reagent used in excess. (Voronkov, page 1505; page 1506)
Voronkov describes the inert solvent and the dehydrating agent as optional. Voronkov states that adding an inert solvent that is insoluble in water, such as toluene or benzene, "has a very advantageous effect," and that adding dehydrating agents "gives better results" than azeotropic distillation of the water. (Voronkov, page 1502)
Vu teaches the solvent-free, base-catalysed depolymerization of silicone waste to siloxane cycles, with the cycles removed by distillation as they form. Vu runs the reaction from 60 to 170° C. under reduced pressure and obtains mixtures of D3, D4 and D5 in yields up to 97 to 99 percent, with D4 the major product. (Vu, abstract; page 3, Tables 1 and 2)
Vu teaches screening the anion of the potassium base. Potassium trimethylsilanolate gave 97 percent, potassium hydroxide 95 percent, and potassium tert-butoxide 97 percent. Potassium tert-butoxide is an alkali metal alkoxide of formula [M+][OR−] in which M is potassium and R is a branched alkyl radical. Vu teaches that the composition of the siloxane mixture is independent of the counter-anion, because once the active silanolate chain end is formed it drives the depolymerization. (Vu, page 3; page 4, Table 3)
Vu teaches that when a real industrial silicone waste is depolymerized the medium becomes too viscous to stir, and that a diluent is therefore needed. Vu teaches adding n-octadecanol, a C18 fatty alcohol, at 10 percent by weight. With 0.5 mol percent of potassium base and no diluent the yield was 10 percent. With 0.5 mol percent of potassium base and 10 percent by weight of n-octadecanol the yield was 75 percent at 150° C. and 5 mbar, and 84 percent at 170° C. and 5 mbar, with D4 accounting for 80 percent of the mixture. On the amounts Vu gives, 0.5 mol percent of potassium tert-butoxide on a 9.5 g charge is about 0.07 g, which is about 7.6 percent by weight of the 0.95 g of n-octadecanol used. (Vu, page 6, Table 5 and the accompanying text)
Vu teaches operating this cyclization in a semicontinuous way. After the volatile cycles are distilled off, the catalyst stays in the distillation flask as a residue together with a small amount of polysiloxane. The flask is then refilled with fresh silicone oil, stirred at 140° C. for one hour, and distilled again under reduced pressure. Vu teaches that no reactivity was lost over the next four runs, with yields of 96 to 97 percent in each of five runs, and that a small amount of silicone oil is always kept in the flask at the end of the distillation. (Vu, page 6, "Recyclability of the catalyst" and Figure 1; Supporting Information, page 3, section 2.4)
Ascertainment of the Difference Between Scope the Prior Art and the Claims
(MPEP §2141.012)
Oku teaches the depolymerization of a waste silicone to siloxane cycles using an alkali metal base, without solvent, with an acid added after the depolymerization and before the cycles are distilled off.
But Oku is deficient in that Oku does not use an alcohol or an alkali metal alkoxide, does not form or isolate an alkoxysiloxane, and does not carry out a later step in which an alkoxysiloxane is heated with a fatty alcohol and an alkali metal alkoxide while the cycles are removed.
Petrus cures the first part of that deficiency. Petrus reacts the same kind of waste silicone with an alcohol and an alkali metal catalyst, with heating, without solvent and without a dehydrating agent, to give alkoxysiloxanes. Petrus also separates the solid residue and distils the excess alcohol off the alkoxysiloxane product.
Voronkov cures the rest of that particular deficiency. Voronkov teaches that the base used to cleave organosiloxanes with alcohols may be an alkali metal alcoholate, that is, an alkali metal alkoxide, and that the hydroxide is converted to the alcoholate in the reaction medium in any event.
Vu cures the last deficiency. Vu heats a silicone with a fatty alcohol and an alkali metal alkoxide, with stirring, while the siloxane cycles that form are removed by distillation, and does so repeatedly by adding fresh substrate to the distillation bottoms.
Finding of Prima Facie Obviousness Rationale and Motivation
(MPEP §2142-2143)
Therefore, it would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the Oku process by first reacting the waste silicone with an alcohol and an alkali metal alkoxide, as taught by Petrus and Voronkov. Oku and Petrus recycle the same waste material, namely cross-linked silicone rubber. Oku gets 46 to 65 percent and works with a mixture that gels. Petrus gets 83 to 95 percent conversion in 2 hours and gets a liquid product. One of ordinary skill would have been motivated to use the alcohol route in order to get a liquid intermediate that can be stirred, filtered and distilled.
Using an alkali metal alkoxide in place of Oku's alkali metal hydroxide is the simple substitution of one known element for another to obtain a predictable result. Voronkov teaches that the hydroxide and the alcoholate are alternatives for the same purpose in the same reaction, and teaches that the hydroxide is converted into the alcoholate in the reaction medium in any event. Petrus separately teaches that sodium ethoxide is conventionally used with alcohols for this purpose. One of ordinary skill would have had a reasonable expectation of success because all three references cleave the same Si-O-Si bond with the same class of base.
Carrying out step (a) without an inert water-insoluble azeotrope-forming solvent, and without a dehydrating agent, would also have been obvious. Oku runs the depolymerization with no solvent at all and teaches that a solvent is undesirable because it must later be removed. Petrus runs the alcoholysis of the same waste with no solvent and no dehydrating agent, and does not remove the water formed. Voronkov examples include when no inert solvent and no dehydrating agent are used. Voronkov calls the inert solvent "very advantageous" and calls the dehydrating agents "better".
Thus, it would have been further prima facie obvious to take the obtained alkoxysiloxane and subject it to the fatty alcohol and alkoxide cyclization of Vu, with thermal removal of the siloxane cycles. Vu supplies the motivation. Vu teaches that in the depolymerization of a real industrial silicone waste the medium becomes too viscous to stir, that the yield without a diluent is only 10 percent, and that adding a C18 fatty alcohol at 10 percent by weight raises the yield to 75 percent and then to 84 percent. One of ordinary skill would have had a reasonable expectation of success because the alkoxysiloxane made by the modified process is a linear polydimethylsiloxane carrying terminal alkoxy groups, which is the same class of substrate Vu depolymerizes.
Applicant's own specification confirms that the parts of the combination were known. Paragraph [0030] states that waste silicones may be depolymerized to afford siloxane cycles in high yields "on the basis of the technical teaching" of the earlier alkoxysiloxane process. Paragraph [0023] acknowledges Vu's teaching that "the fatty alcohol addition effectively counters the formation of siloxane structures linked via T-units."
Note that an express suggestion to substitute one equivalent component or process for another is not necessary to render such substitution obvious. In re Fout, 675 F.2d 297, 213 USPQ 532 (CCPA 1982). The use of an alkali metal alkoxide in place of an alkali metal hydroxide, and the addition of a known fatty alcohol diluent to a base-catalysed depolymerization, are predictable changes to known silicone recycling reactions.
With regard to claim 17, none of Oku, Petrus or Vu uses a water-binding silicic ester or a tetraalkoxysilane. The Voronkov example using n-amyl alcohol uses none either. (Oku, page 7290; Petrus, page 2464; Voronkov, page 1505)
With regard to claim 18, Vu teaches potassium tert-butoxide, in which M is potassium and R is a branched alkyl radical. Voronkov teaches alkali metal alcoholates generally and works an example with sodium n-butoxide, in which M is sodium and R is a linear alkyl radical. (Vu, page 4, Table 3; Voronkov, page 1501 and footnote; page 1505)
With regard to claim 19, Petrus uses n-octanol, n-nonanol and n-decanol, which are linear C8 to C10 alkanols. Voronkov uses alcohols of 4 to 12 carbon atoms, which overlaps the claimed C1 to C10 range. Where a prior art range overlaps a claimed range, a prima facie case of obviousness exists. MPEP § 2144.05(I). (Petrus, page 2459; page 2464; Voronkov, page 1502)
With regard to claim 20, Petrus uses n-octanol, n-nonanol and n-decanol, which are octanol, nonanol and decanol as recited. (Petrus, page 2459; page 2464)
With regard to claim 21, Petrus teaches that the amount of alcohol is a variable that controls the conversion of the silicone rubber. Where the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation. MPEP § 2144.05(II). One of ordinary skill would have been motivated to use the smallest amount of alcohol that still gives an acceptable conversion, in order to use less alcohol and to reduce the load on the later distillation. Voronkov confirms that amounts inside the claimed range work, because Voronkov boils 44.1 g of n-amyl alcohol with 60.0 g of siloxane, which is 73.5 percent by mass, and states that the siloxane rather than the alcohol was often the reagent used in excess. (Petrus, page 2456 and Figure 9; Voronkov, page 1505; page 1506)
With regard to claim 22, Voronkov uses 1 to 10 mole percent of the alkali metal alcoholate. On a dimethylsiloxy unit basis this is about 1.9 to 18.9 percent by mass for the potassium alcoholate of n-amyl alcohol, and about 1.1 to 11.4 percent by mass for potassium ethoxide. Both fall inside the claimed range of 1 to 20 percent by mass. Oku's KOH amounts of 2.1 to 9.8 percent by mass fall inside the claimed range as well. MPEP § 2144.05(I). (Voronkov, page 1501; Oku, page 7291, Table 1)
With regard to claim 23, Oku adds citric acid, an organic acid, to the basic reaction mixture after the depolymerization and before the distillation. Oku adds the acid to a mixture that contains no solvent and no water, and Oku's citric acid melts at 153° C., which is the melting point of the anhydrous form. It would in any event have been obvious to use the acid in anhydrous form, because added water would reverse the alcoholysis and hydrolyse the alkoxy groups. (Oku, page 7292, section 3.2 and Table 2)
With regard to claim 25, step (b) of the combined process still contains the excess alcohol carried over from step (a), because that alcohol is only distilled off later in step (b). Claim 25 lists alcohols. Oku separately teaches running the depolymerization in toluene, an alkylaromatic, and it would have been obvious to keep a solvent present during the neutralization in order to keep the salt-laden mixture stirrable and easy to filter. (Petrus, page 2460, "Materials and Methods"; Oku, page 7290, section 2.2)
With regard to claim 26, Petrus runs the alcoholysis at 180 to 240° C., and runs the catalysed reactions at 200 to 220° C. Voronkov boils the mixtures under reflux with alcohols boiling above 100° C. These fall inside or overlap the claimed range of 50 to 200° C. MPEP § 2144.05(I). (Petrus, pages 2455 and 2458; Voronkov, page 1501)
With regard to claim 27, Petrus runs the catalysed reactions for 2 hours, which is inside the claimed 0.5 to 12 hours. Petrus runs them in a sealed steel high-pressure reactor at 180 to 240° C., so the pressure is above atmospheric, and Petrus teaches that a higher pressure in the reactor gives a higher conversion of the silicone rubber. Pressure is therefore a variable that controls the result, and choosing a value above 1013.25 hPa would have been obvious. Choosing a value below 12000 hPa would also have been obvious, because that is the limit set by ordinary pressure equipment such as the 20 mL PTFE-lined vessel Petrus uses. MPEP § 2144.05(II). (Petrus, pages 2455, 2458, 2459 and 2464)
With regard to claim 28, Vu adds a fresh amount of substrate to the distillation bottoms, which hold the catalyst and a small amount of siloxane, and then restarts the formation and distillation of the siloxane cycles. Vu repeats this over five runs with no loss of yield. Claim 28 is written in the alternative, so this teaching alone meets the claim. (Vu, page 6, "Recyclability of the catalyst" and Figure 1; Supporting Information, page 3, section 2.4)
With regard to claim 29, Vu uses n-octadecanol, a C18 fatty alcohol, which falls inside the claimed C12 to C18 range. (Vu, page 6, Table 5)
With regard to claim 30, Vu uses the fatty alcohol at 10 percent by weight, and Petrus uses the alcohol at 2 to 8 equivalents per siloxane unit, which is more than 350 percent by weight. The claimed range of 20 to 50 percent by weight lies between these two values. Vu further teaches that the amount of fatty alcohol controls the result, because it controls the viscosity of the medium and raises the yield of cycles from 10 percent to 75 percent and then to 84 percent. Choosing the amount of fatty alcohol would therefore have been routine optimization. MPEP § 2144.05(I) and (II). (Vu, page 6, Table 5; Petrus, page 2455; page 2456 and Figure 9)
With regard to claim 31, Vu uses 0.5 mol percent of the potassium base together with 10 percent by weight of n-octadecanol on a 9.5 g charge. For potassium tert-butoxide this is about 7.6 percent by weight of alkoxide on the fatty alcohol. The claimed range of 10 to 20 percent by weight is so close to that value that one of ordinary skill would have expected the same result. See Titanium Metals Corp. v. Banner, 778 F.2d 775, 783 (Fed. Cir. 1985); MPEP § 2144.05(I). Oku further teaches that the amount of base controls the yield and has an optimum, so optimizing it would have been routine. MPEP § 2144.05(II). (Vu, page 4, Table 3; page 6, Table 5; Oku, page 7291, Figure 1)
With regard to claim 32, Vu runs the cyclization at 140 to 170° C., which is inside the claimed range of 100 to 200° C. Vu heats for 1 hour and then distils for up to 3 hours, which is inside the claimed 1 to 12 hours. (Vu, page 6, Table 5; page 7, Experimental Section)
Claims 24 and 33-35 are rejected under 35 U.S.C. 103 as being unpatentable over Oku, in view of Petrus, further in view of Voronkov, and further in view of Vu, as applied to claims 20 and 23 above, and further in view of Knott et al. (US 20200377686, pub date Dec. 3, 2020) ("Knott" herein).
Determination of the Scope and Content of the Prior Art
(MPEP §2141.01)
Knott teaches a process for recycling silicones, in particular silicone rubber and silicone oils, by heat treatment in a digestion system that includes at least one Brønsted acid. (Knott, abstract; paragraph [0040])
Knott teaches which Brønsted acids are used for this purpose. They include protic acids with a pKa of less than −1.30, such as nitric acid, methanesulfonic acid and para-toluenesulfonic acid; protic acids with a pKa of less than −2.90, such as concentrated sulfuric acid; and protic acids with a pKa of less than −4.90, such as the perfluoroalkanesulfonic acids, perchloric acid and chlorosulfonic acid. Knott also adds acetic acid to the digestion system in amounts of 0.5 to 4.0 percent by mass, and works an example in which 0.69 g of concentrated sulfuric acid is used with a cured silicone joining compound. (Knott, paragraphs [0044]-[0046]; paragraph [0055]; paragraph [0088])
Ascertainment of the Difference Between Scope the Prior Art and the Claims
(MPEP §2141.012)
Oku neutralizes the basic depolymerization mixture with an acid before the cycles are distilled off, and teaches an organic acid among the acids used.
Oku is deficient in that Oku does not name anhydrous sulfuric acid, anhydrous perchloric acid or anhydrous acetic acid.
Knott cures this deficiency. Knott names sulfuric acid, perchloric acid and acetic acid as the Brønsted acids used in silicone recycling systems.
Finding of Prima Facie Obviousness Rationale and Motivation
(MPEP §2142-2143)
Therefore, it would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to use anhydrous sulfuric acid, anhydrous perchloric acid or anhydrous acetic acid as the Brønsted acid in the neutralization step, as taught by Knott.
Oku already teaches that an acid must be added to neutralize the alkali metal silanolate, and teaches what acid strength is wanted. Knott teaches which Brønsted acids are used in silicone recycling and gives their acid strengths, and works an example with concentrated sulfuric acid. Choosing one of those acids for the neutralization is a choice from a small number of known and predictable options, with a reasonable expectation of success. Using the acid in anhydrous form would have been obvious because the medium is anhydrous once the alcohol has been distilled off, and because added water would reverse the alcoholysis and hydrolyse the alkoxy groups.
Note that an express suggestion to substitute one equivalent component for another is not necessary to render such substitution obvious. In re Fout, 675 F.2d 297, 213 USPQ 532 (CCPA 1982).
With regard to claim 33, the acid limitation is the same as in claim 24 and is met for the same reason. (Knott, paragraphs [0044]-[0046]; paragraph [0088])
With regard to claim 34, Vu uses n-octadecanol, a C18 fatty alcohol, which falls inside the claimed C12 to C18 range. (Vu, page 6, Table 5)
With regard to claim 35, the alkoxide amount limitation is the same as in claim 31 and is met for the same reason. (Vu, page 4, Table 3; page 6, Table 5; Oku, page 7291, Figure 1)
Double Patenting
The nonstatutory double patenting rejection is based on a judicially created doctrine grounded in public policy (a policy reflected in the statute) so as to prevent the unjustified or improper timewise extension of the "right to exclude" granted by a patent and to prevent possible harassment by multiple assignees. See In re Goodman, 11 F.3d 1046, 29 USPQ2d 2010 (Fed. Cir. 1993); In re Longi, 759 F.2d 887, 225 USPQ 645 (Fed. Cir. 1985); In re Van Ornum, 686 F.2d 937, 214 USPQ 761 (CCPA 1982); In re Vogel, 422 F.2d438, 164 USPQ 619 (CCPA 1970); and In re Thorington, 418 F.2d 528, 163 USPQ 644 (CCPA 1969).
A timely filed terminal disclaimer in compliance with 37 CFR 1.321(c) may be used to overcome an actual or provisional rejection based on a nonstatutory double patenting ground provided the conflicting application or patent is shown to be commonly owned with this application. See 37 CFR 1.130(b).
Effective January 1, 1994, a registered attorney or agent of record may sign a terminal disclaimer. A terminal disclaimer signed by the assignee must fully comply with 37 CFR 3.73(b).
The USPTO internet Web site contains terminal disclaimer forms which may be used. Please visit http://www.uspto.gov/forms/. The filing date of the application will determine what form should be used. A web-based eTerminal Disclaimer may be filled out completely online using web-screens. An eTerminal Disclaimer that meets all requirements is auto-processed and approved immediately upon submission. For more information about eTerminal Disclaimers, refer to http://www.uspto.gov/patents/process/file/efs/guidance/eTD-info-I.jsp.
Claims 16-23 and 25-32 are provisionally rejected on the ground of nonstatutory obviousness-type double patenting as being unpatentable over claims 1-26 of copending Application No. 18447540 ('540 herein), in view of Vu et al. ("Back-to-cyclic-monomers: chemical recycling of silicone wastes using a [polydentate ligand-potassium silanolate] complex," ChemRxiv, posted January 4, 2023, in applicant’s IDS filed 4/7/24), and further in view of Petrus et al. ("Solvothermal Alcoholysis Method for Recycling High-Consistency Silicone Rubber Waste," Macromolecules 2021, 54, 2449-2465).
The teachings of Vu and Petrus have been discussed previously within this office action.
Claim 1 of '540 is directed to a process for producing one or more alkoxysiloxanes by a thermal reaction of at least one waste silicone with at least one alkali metal alkoxide and at least one alcohol, comprising (a) reacting the waste silicone by mixing with at least one alcohol and at least one alkali metal alkoxide with heating but without removing any potentially occurring water from the reaction mixture, (b) neutralizing the reaction mixture with at least one Brønsted acid, optionally with an addition of at least one solvent, and separating by filtration the solid constituents, and (c) subsequently isolating the alkoxysilane(s) by thermal separation of volatile compounds.
Although the claims at issue are not identical, they are not patentably distinct from each other because steps (a) and (b) of instant claim 16 correspond in substance to the whole of the process claimed in '540. Instant claim 16 differs only by adding step (c). The rest of the claims similarly substantially overlap in scope.
The only difference is step (c) of instant claim 16, in which the alkoxysiloxane obtained by the '540 process is heated with at least one fatty alcohol and at least one alkali metal alkoxide with mixing while the siloxane cycles formed are thermally removed. Claims 28-32 are further limitations on that step.
That difference does not make the instant claims patentably distinct.
Vu heats a silicone with a fatty alcohol, n-octadecanol, and an alkali metal alkoxide, potassium tert-butoxide, while the cycles formed are removed by distillation under reduced pressure, and teaches that the fatty alcohol keeps the medium stirrable and raises the yield to 84 percent.
Petrus teaches that fatty alcohols and alkali metal catalysts convert the same waste silicones to alkoxysiloxanes of the kind claimed in '540.
One of ordinary skill in possession of the '540 claims would have found it obvious to subject the alkoxysiloxane produced by those claims to the Vu cyclization in order to obtain siloxane cycles, for the reasons given in the 35 U.S.C. 103 rejection above.
Claims 24 and 33-35 are provisionally rejected on the ground of nonstatutory obviousness-type double patenting as being unpatentable over claims 1-26 of copending Application No. 18/447,540, in view of Vu et al. and Petrus et al. as applied above, and further in view of Knott et al. (US 20200377686).
The teachings of Knott have been discussed previously within this office action.
Claims 8 and 23 of '540 already recite anhydrous sulfuric acid, anhydrous perchloric acid and anhydrous acetic acid, and Knott names the same acids for silicone recycling.
Claim 34 recites the C12 to C18 fatty alcohol taught by Vu. Claim 35 recites the amount of alkali metal alkoxide addressed above.
This is a provisional obviousness-type double patenting rejection, because the conflicting claims have not in fact been patented.
Conclusion
No claim is allowed.
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/JENNIFER C SAWYER/Examiner, Art Unit 1691
/RENEE CLAYTOR/Supervisory Patent Examiner, Art Unit 1691
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