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 .
Response to Amendment
In view of the amendment filed 01/15/2026:
Claims 1-4 are pending.
Claims 5-9 are withdrawn from further consideration.
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 text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
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) 1-3 are rejected under 35 U.S.C. 103 as being unpatentable over Takatori et al. (“Microstructural evolution of high purity alumina ceramics”, Journal of the Ceramic Society of Japan 124, 4, 2016, pg. 432-441), and further in view of Aramaki (JP2012023335A- Machine translation provided herein) and as evidenced by Wikipedia (“Aluminum Oxide”; https://en.wikipedia.org/wiki/Aluminium_oxide- see attached) and Sigma Aldrich (“Poly(vinyl butyral-co-vinyl alcohol-co-vinyl acetate)”; https://www.sigmaaldrich.com/US/en/product/aldrich/182567?srsltid=AfmBOopadAofSZu8pCHTfpBqOBAujeC-9-Mn8Gcae4hWxGox1P_iy6AQ- see attached).
Regarding claim 1, Takatori teaches a method of producing a ceramic sheet (Abstract: “Textured α-alumina ceramics were prepared by mixing different ratios of three-sized plate-like α -alumina particles and fine equiaxed particles without the use of sintering aids” and see “2.2 Forming” on pg. 433) comprising:
shaping a composition containing a resin and a ceramic material into a sheet-like form through pressure application to obtain a primary sheet (“The powders were weighed in the ratio in Table 1 for total 20.4 g in each batch and mixed together with 2.2 g of polyvinyl butyral (PVB) and 36.5 ml of organic solvents (ethanol: toluene = 2:3) in a polyethylene pot with alumina balls. After ball-milling for 20 h, the slurry was formed into a sheet with a thickness of ca. 100 ¯m using a doctor blade with a slit spacing of 0.5 mm”- see pg. 433),
wherein a volume fraction of the ceramic material in the primary sheet is not more than 65 volume% based on total volume of the resin and the ceramic material (“The powders were weighed in the ratio in Table 1 for total 20.4 g in each batch and mixed together with 2.2 g of polyvinyl butyral (PVB) and 36.5 ml of organic solvents (ethanol: toluene = 2:3) in a polyethylene pot with alumina balls”; the volume of alumina is determined by dividing 20.4 g by the density of alumina, which if 3.987 g/cm3 as taught by Wikipedia, to obtain a volume of 5.1 cm3 or mL and the volume of PVB is determined by dividing 2.2 g by the density of PVB, which is 1.083 g/mL as taught by Sigma Aldrich, to obtain a volume of 2.0 mL. The volume% of alumina is determined by dividing the volume of alumina by the total volume in the solution, which is 5.1/(5.1+2.0+36.5)= 11.7 vol%);
stacking a plurality of the primary sheet in a thickness direction to obtain a laminate (“The sheet was cut at regular intervals and laminated to prepare a plate specimen with a thickness of ca. 5mm using a heater press (80°C, 10 MPa).”- see pg. 433); and
firing the secondary sheet so as to obtain the ceramic sheet (“The dewaxed plate specimens (10 x 10 x 5mm3) were sintered in an electrical furnace at 1400, 1600 and 1700°C for 4 h and 1700°C for 20 h in air” see pg. 433).
While Takatori fails to explicitly teach the fired ceramic sheets having a value a/c of not less than 60.30, obtainable by dividing a-axis value by c-axis value upon Lotgering method, Takatori does teach that the degree of crystal orientation is determined according to the Lotgering method (see “2.3 Characterization” on pg. 433), and that the size of plate-like ceramic particles, the weight fractions, and sintering temperature will vary peak intensities corresponding to crystallographic planes in x-ray diffraction patterns (see “3.3 XRD of sintered bodies” on pg. 434-435).
Further, for alumina-based laminated sheets, Applicant’s disclosure determines the a-axis value from the (300) plane intensity and the c-axis value from the (006) plane intensity. The a/c ratio is then determined by dividing the (300) plane intensity by the (006) plane intensity (see the Table on pg. 8 of PgPub US20240360046A1).
Takatori teaches alumina XRD patterns with varying intensities for the (006) plane found at 2θ= 41.6° and for the (300) plane found at 2θ=68.1° in Figure 4 on pg. 435 according to varying plate-like ceramic particle sizes, weight fractions, and sintering temperatures, including no intensity in the (006) plane for Tref particles containing only equiaxed-grain α-alumina, a decreasing intensity in the (006) plane with increased alumina particle loading, and an increasing intensity in the (006) plane with increasing sintering temperatures (see XRD patterns for sintering at 1400 °C and 1700 °C in Figure 4).
Therefore, it would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to for the fired ceramic sheets of Takatori to have a value a/c of not less than 60.30, obtainable by dividing a-axis value by c-axis value upon Lotgering method by routine optimization (see MPEP 2144.05.II). The alumina crystallographic orientation and resulting microstructure in a laminate can improve flexural strength and anisotropy of the thermal expansion coefficients (“grains with uniformly aligned crystal axes, improved flexural strength, and 10% anisotropy of the thermal expansion coefficients by”- see pg. 432), and one of ordinary skill would be motivated to optimize result effective variables such as plate-like ceramic particle sizes, weight fractions, and sintering temperatures to improve the flexural strength and anisotropy of the thermal expansion coefficients .
While Takatori teaches cutting a sheet at regular intervals to form multiple sheets that are then laminated (see “2.2 Forming” on pg. 433), Takatori fails to teach slicing the laminate at an angle of 45° or less relative to a stacking direction to obtain a secondary sheet.
In the same field of endeavor pertaining to method of producing a ceramic sheet, Aramaki teaches slicing the laminate at an angle of 45° or less relative to a stacking direction to obtain a secondary sheet (“The angle formed by the thickness direction of the cured product (thermally conductive sheet) cut to a predetermined thickness by the ultrasonic cutter and the anisotropic thermally conductive filler is 5 ° to 45 °, and 5 ° to 30 °. Is preferred. If the angle formed is less than 5 °, the compression ratio is 0 °, and if it exceeds 45 °, the thermal resistance value may increase.”- see pg. 7). Cutting the laminate at an angle of 45° or less relative to a stacking direction decreases the surface roughness on the cut surface and results in a high thermal conductivity in the thickness direction (“Therefore, since the surface roughness of the cut surface is small, the thermal resistance at the interface is low, the thermal conductivity in the thickness direction is high”- see pg. 2).
It would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to slice the laminate of modified Takatori at an angle of 45° or less relative to a stacking direction to obtain a secondary sheet, as taught by Aramaki, for the benefit of decreasing the surface roughness on the cut surface that results in a high thermal conductivity in the thickness direction.
Regarding claim 2, modified Takatori modified with Aramaki teaches the method of producing a ceramic sheet according to claim 1. Further, Takatori teaches wherein debinding of the secondary sheet through heating in an atmosphere of 600°C is performed in advance of the firing (“The plate was heated to remove organic binder at a heating rate of 10°C·h¹1 in an electric furnace of air circulation and soaked at 600°C for 2 h”- see pg. 433), and the firing is performed in an atmosphere of 1400 °C, 1600 °C, and 1700 °C (“The dewaxed plate specimens (10 © 10 © 5mm3) were sintered in an electrical furnace at 1400, 1600 and 1700°C for 4 h and 1700°C for 20 h in air. Heating and cooling were conducted at a heating rate of 300°C·h¹1”- see pg. 433).
Regarding claim 3, modified Takatori modified with Aramaki teaches the method of producing a ceramic sheet according to claim 1. Further, Takatori teaches wherein the primary sheet has a thickness of 100 µm (“After ball-milling for 20 h, the slurry was formed into a sheet with a thickness of ca. 100 µm using a doctor blade with a slit spacing of 0.5 mm”- see pg. 433)
Claim(s) 4 is rejected under 35 U.S.C. 103 as being unpatentable over Takatori et al. (“Microstructural evolution of high purity alumina ceramics”, Journal of the Ceramic Society of Japan 124, 4, 2016, pg. 432-441), and Aramaki (JP2012023335A- Machine translation provided herein) as evidenced by Wikipedia (“Aluminum Oxide”; https://en.wikipedia.org/wiki/Aluminium_oxide- see attached) and Sigma Aldrich (“Poly(vinyl butyral-co-vinyl alcohol-co-vinyl acetate)”; https://www.sigmaaldrich.com/US/en/product/aldrich/182567?srsltid=AfmBOopadAofSZu8pCHTfpBqOBAujeC-9-Mn8Gcae4hWxGox1P_iy6AQ- see attached), and further in view of Yamagata et al. (JP2012201106- Machine translation provided herein).
Regarding claim 4, modified Takatori modified with Aramaki teaches the method of producing a ceramic sheet according to claim 1. However, Takatori fails to teach wherein the volume fraction of the ceramic material in the primary sheet is not less than 50 volume% based on the total volume of the resin and the ceramic material.
In the same field of endeavor pertaining to a method for producing a ceramic sheet, Yamagata teaches improving the thermal conductivity of a material by adding a filler with high thermal conductivity such as aluminum powder (“In order to improve the thermal conductivity of the thermally conductive material, a method in which a filler having high thermal conductivity such as an aluminum oxide powder, a boron nitride powder, and an aluminum nitride powder is contained in the polymer has been generally used”- see pg. 2).
Further, Yamagata teaches a volume fraction of a ceramic material in a primary sheet between 40-70 vol% based on total volume of the resin and the ceramic material (Abstract: wherein the silicone laminate is formed by laminating a silicone resin composition containing 40-70 vol.% thermoconductive filler obtained by blending hexagonal boron nitride powder (A) having 20-50 μm average particle size with aluminum oxide powder (B)). A volume fraction of 40-70 vol% of ceramic material is optimal, because a volume fraction less than 40 vol% forms sheets with reduced heat conductivity and a volume fraction exceeding 70 vol% may impair the mechanical strength of the sheet (“The content of the thermally conductive filler in the thermally conductive molded body of the present invention is preferably 40 to 70% by volume,
particularly 50 to 60% by volume in the entire volume. If the content rate of a heat conductive
filler is less than 40 volume%, it exists in the tendency for the heat conductivity of a heat
conductive molded object to reduce. Moreover, when it exceeds 70 volume%, it exists in the
tendency for the mechanical strength of a molded object to be impaired.”- see pg. 3 paragraph
1).
Therefore, it would have been obvious before the effective filing date of the claimed
invention to a person having ordinary skill in the art to have a volume fraction of the ceramic
material in the primary sheet of modified Takatori modified with Aramaki be between 50-65 vol.% based on total volume of the resin and the ceramic material, as taught by Yamagata. One of ordinary skill would be motivated to use a range between 50-65 vol.%, since it has a high enough ceramic material content where heat conductivity is not reduced but not high enough to impair the mechanical strength of a molded object.
Response to Arguments
Applicant’s arguments with respect to claim(s) 1 have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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/ARIELLA MACHNESS/Examiner, Art Unit 1743