Board of Patent Appeals and Interferences
Patent and Trademark Office (P.T.O.)
*1 EX PARTE RAYCHEM CORPORATION
Appeal No. 90-0857
July 20, 1990
HEARD: June 4, 1990
Request filed March 2, 1987, Control No. 90/001,178; and Request filed May 11, 1987, Control No. 90/001240 for the Reexamination for Patent No. 4,426,339, issued January 17, 1984, based on application Serial No. 06/251,910 filed April 7, 1981, which is a continuation of Serial No. 06/024,369 filed March 27, 1979; now abandoned. Method Of Making Electrical Devices Comprising Conductive Polymer Compositions.
Timothy H.P. Richardson for Patent Owner
Charles M. Cox et al. for Third Party Requestor
Primary Examiner--James Derrington
Before Seidleck, Tarring and W. Smith
Examiners-in-Chief
W. Smith
Examiner-in-Chief
This is an appeal from the final rejection of claims 1 through 41, which are all of the claims pending in this reexamination of U.S. Patent No. 4,426,339. Claim 1 is representative of the subject matter on appeal in this reexamination proceeding and reads as follows:
1. A process for the preparation of an electrical device which has improved resistance stability under service conditions, which comprises at least two electrodes, each of said electrodes being in physical and electrical contact with a conductive polymer composition, and in which, when said electrodes are connected to a source of electrical power, current passes between the electrodes through the conductive polymer composition, which process comprises contacting each of said electrodes with a conductive polymer composition by
(1) heating a thermoplastic electrically conductive polymer composition above its melting point;
(2) heating each electrode, in the absence of the conductive polymer composition, to a temperature above the melting point of the conductive polymer composition;
(3) bringing each electrode which has been heated in step (2), while it is at a temperature above the melting point of the conductive polymer composition, into direct physical contact with the molten conductive polymer composition prepared in step (1); and
(4) cooling each electrode and conductive polymer composition in contact therewith prepared in step (3),
whereby the contact resistance between each of the electrodes and the conductive polymer in contact therewith is reduced.
The references relied upon by the examiner are:
Bedard et al. (Bedard) 3,858,144 Dec. 31, 1974
Gale et al. (Gale) 4,444,708 Apr. 24, 1984
Griff, "Plastics Extrusion Technology", Robert E. Krieger Publishing Co., 2nd Edition, Chapter 7, pages 193-233 (1968).
Metals Handbook, "Properties and Selection of Metals", Vol. 1, 8th Edition, page 41 (1961).
References relied upon by the Board are:
Richart et al. (Richart) 3,503,823 Mar. 31, 1970
Smith-Johannsen et al. (Smith-Johannsen) 3,861,029 Jan. 21, 1975
*2 Claims 1 through 41 stand rejected under 35 USC § 103 as unpatentable over the combined disclosures of Bedard and Griff. We affirm.
BACKGROUND
The patent undergoing reexamination in this proceeding, U.S. Patent No. 4,426,339, ('339 patent), is assigned to Raychem Corp. (Raychem). The patent owner requested reexamination of this patent on March 2, 1987, which was ordered on May 8, 1987. On May 11, 1987, a second request for reexamination of the '339 patent was filed by an alleged infringer, Thermon Manufacturing (Thermon) [FN1], which was ordered on July 24, 1987. The two reexamination proceedings were merged by decision of the Group Director on November 10, 1987 which resulted in a single proceeding and consequently, a single appeal.
Claims 1 through 28 on appeal are identical to those issued in the '339 patent except for certain amendments which have been entered by the examiner during the reexamination proceeding which were directed to obvious errors in these claims. Claims 29 through 41 are new, having been added during the reexamination. As seen from claim 1, the claimed invention is directed to a process for preparing an electrical device which comprises at least two electrodes, each of which being in physical and electrical contact with a conductive polymer composition. The electrical device is preferably a self-regulating strip heater where the conductive polymer composition comprises carbon black and exhibits so-called positive temperature coefficient (PTC) behavior. As set forth in the specification of the '339 patent, conductive polymer compositions were well known at the time of the present invention and were used in electrical devices in which the composition was in contact with an electrode(s), usually of metal. These devices, including self-regulating strip heaters, were usually manufactured by extruding or molding the molten conductive polymer composition around or against the electrode(s). The specification discloses at column 2, lines 3-8 that a particular disadvantage arose with the prior art devices in that the longer they were in service, their resistance became higher and their power output became lower, especially when these devices were subjected to thermal cycling. The claimed invention revolves around the discovery by the inventors of the '339 patent that minimizing the initial contact resistance between the electrode and the conductive polymer composition will result in a smaller increase in total resistance with time. The '339 patent sets forth several alternative methods of decreasing the initial contact resistance of these electrical devices. The claims of the '339 patent are directed to one of these embodiments, i.e., heating each electrode in the absence of the conductive polymer composition to a temperature above the melting point of the conductive polymer composition and bringing the electrodes while they are at a temperature above the melting point of the conductive polymer composition into direct physical contact with the molten conductive polymer composition as the device is being extruded.
PRIMA FACIE CASE
*3 Bedard discloses methods of forming electrical devices, including self-regulating heaters, which comprise two electrodes in physical and electrical contact with a conductive polymer composition. The specific invention disclosed in Bedard revolves around a problem such electrical devices have concerning their increased resistance over time. Bedard discloses (column 2, lines 2-12) that this problem appears to be related to high voltage stress resulting from the combined influence of high operational voltage and the relative contiguity of the electrodes. Bedard theorizes that this problem is caused by the disperse nature of the conductive carbon in the conductive polymer composition which surrounds the electrodes and incomplete wetting of the electrode with the carbon black-containing polymer. Under high voltage stress, regions of high localized current density are created which lead to degradation and a concomitant increase of resistance at the interface, i.e., contact resistance.
Bedard discloses two methods for ameliorating this problem. The first is to precoat the metallic electrodes with a conductive carbon black-containing composition so that, following extrusion of the conductive polymer composition onto the electrodes, the percentage by weight of the conductive carbon black contained at the electrode interface is at least about 1.5 times that of the midpoint between adjoining electrodes. The second method is uniformly deplying an effective resistance-stabilizing amount of certain carboxylic acid group-containing polymers or polymeric amines in the conductive polymer composition. Bedard discloses at column 3, lines 6-37 that the resistivity stabilization which results from the second method may be owed to improved wetting [FN2] of the electrode stemming from the formation of ionic or other bonds between the functional groups of the additives and the electrode.
The molten conductive polymer composition of Bedard is extruded onto and around the electrodes in order to form the electrical device. As set forth at column 5, lines 31-57 of Bedard, it is preferred to anneal the extruded product in order to reduce its resistivity to acceptable initial levels. The annealing step takes place at temperatures above the melting point of the conductive polymer composition.
The purpose of the optional annealing step in Bedard is amplified in Smith-Johannsen which is incorporated by reference by Bedard at column 1, lines 20- 23. Smith-Johannsen discloses that the initial resistivity of self-regulating heaters having a low carbon loading in the conductive polymer composition, e.g., less than 15-20% by weight carbon may be regulated if the extruded product is annealed. As disclosed at column 2, lines 47-60 of Smith-Johannsen, the electrical device is extruded in conventional fashion followed by annealing or "thermal structuring" according to a time-temperature regime which is more severe than that previously used for strain relief or improving electrode wetability. Smith-Johannsen reiterates at column 4, lines 38-44 that the annealing conditions are such that the extruded product is exposed to temperatures above the melt of the conductive polymer composition for periods substantially longer than those which "heretofore have been employed to improve electrode wetting."
*4 The examiner's position is based upon that portion of Bedard's theory that the problem discussed in the reference may be in part attributed to an incomplete wetting of the electrode with the conductive polymer composition. The examiner relies upon a definition of the term "wetting" which appears in Metals Handbook which reads as follows:
wetting. A phenomenon involving a solid and a liquid in such intimate contact that the adhesive force between the two phases is greater than the cohesive force with the liquid. Thus a solid that is wetted, on being removed from the liquid bath, will have a thin continuous layer of liquid adhering to it. Foreign substances such as grease may prevent wetting. Additional agents, such as detergents, may induce wetting by lowering the surface tension of the liquid. For a contrast, see water break.
The examiner has concluded that to the extent that the prior art electrical devices or self-regulating heaters suffered from incomplete wetting of the electrodes by the conductive polymer composition, one of ordinary skill in the art would have recognized that incomplete wetting involves incomplete adhesion of the conductive polymer composition to the metal electrode.
The examiner's position is supported by the above referenced portions of Smith-Johannsen which acknowledge that wetting of the electrode by the conductive polymer composition was indeed a concern in forming devices of the type produced by the present invention. The examiner has also relied upon Gale as evidence that electrode wetting by the conductive polymer composition was a real concern in the prior art at the time the present invention as made. [FN3] (Supplemental Examiner's Answer, Paper No. 40, page 3). Specifically, Gale discloses in column 1, lines 32-column 2, line 21, that high contact resistance between the electrodes and the conductive polymer composition had been a continuing problem in prior art self-regulating heaters and was due to the difficulty of achieving metal adhesion to common PTC materials. The temperature cycling to which these prior art devices were exposed during use caused an increase in the resistance at the electrode interface (contact resistance) due to "breakdown in the already poor adhesion between the electrode and the bulk material and the accelerated oxidation and reaction of the PTC material at the electrode interface." (Column 1, lines 43-49). Gale then discusses Bedard and specifically states that Bedard attempted to ameliorate these problems, i.e., breakdown in the already poor adhesion of the conductive polymer composition to the electrode(s).
Thus, at the time of the present invention, those of ordinary skill in this art recognized that high contact resistance between the electrodes and the PTC material of self-regulating heaters was due, at least in part, to incomplete wetting or poor adhesion of the conductive polymer material to the electrode.
Griff is a textbook about plastic extrusion technology. The portion of Griff relied upon by the examiner is a chapter which discloses conventional techniques for covering wire and cable by extrusion. Inasmuch as Smith-Johannsen discloses that the electrical devices, including self-regulating heaters, are formed by conventional melt extrusion processes, Griff is clearly relevant prior art to the claimed invention. Griff discloses on page 197 that preheating of the conductor affects adhesion of the extruded plastic coating to the conductor. At page 208 Griff discloses that for most plastics a preheat temperature of 150<<degrees>> C is desirable and that high-density polyethylenes do better when a temperature of 175<<degrees>> C is used. Griff also discloses on page 225 that semi-conductive insulation, which the conductive polymer compositions of the present invention are, may be extruded onto electrodes or conductors on "standard equipment, as long as care is taken to avoid excessive shearing."
*5 The examiner has concluded, based upon the combined disclosures of Bedard and Griff, that one of ordinary skill in this art at the time the present invention was made would have recognized the prior art problem of incomplete electrode wetting by the conductive polymer composition, the so-called adhesion problem, may be minimized if the electrodes are preheated prior to being contacted with the molten polymer in the extruder as disclosed by Griff.
Inasmuch as the problem of electrode or conductor wetting by the conductive polymer composition in the electrical devices or self-regulating heaters of present concern involves the contact and adhesion of the polymer composition at the interface between the polymer composition and the metal electrode or conductor, we find Richart to be relevant to the present obviousness determination. Richart is concerned with the problem of adhesion of thermoplastic coatings to metal strip, wire or pipe. Specifically, Richart discloses that adhesion of such coatings is improved by extruding the thermoplastic material onto the metal and heat treating the interface between the coating and the metal at a temperature above that at which the extrusion is done either during or after the extrusion step. The adhesion promoting heat treatment step of Richart may be performed in several different ways. See generally columns 3 and 4 of the reference. Richart discloses at column 3, lines 6-46 that the substrate, e.g., a wire, may be preheated to the required temperature prior to the time that it passes through the extruder as in the present invention. While this preheating method is within the scope of Richart's invention, it is not preferred for the reasons set forth in column 3 of the reference.
An alternative embodiment, also within the scope of Richart's invention, is to place the substrate, e.g., wire, which has been coated by extrusion in a high temperature oven as in the annealing process of Bedard. Richart discloses at column 3, lines 52-63 that this post extrusion oven heating may sometimes be more satisfactory than preheating the substrate but it suffers from practical difficulties, i.e., requires large heating ovens, exposure of the coating to high temperatures for extended periods of time can cause degradation or otherwise damage to the coating, and the difficulty of handling the coated substrate after it leaves the oven until the coating and substrate have been cooled below the softening point of the coating. Richart specifically discloses that if the heating capacity of the substrate is large the cooling time may be quite long.
The preferred and most convenient method disclosed in Richart for performing the invention of that reference is to utilize techniques that do not require the total mass of both the substrate and coating to be heated since it is only necessary to provide the requisite temperature at the interface between the coating and the substrate in order to promote adhesion. Therefore, Richart prefers to use heating techniques which provide for partial or localized heating at the interface. The disclosed techniques include dielectric heating where only the coating layer itself is heated, resistance heating where the metallic substrate may be used to selectively heat the interface, ultrasonic heating or induction heating.
*6 Thus, at the time the present invention was made, one of ordinary skill in this art would have recognized that the unannealed electrical devices or self-regulating heaters of Bedard would not have optimum conductive polymer composition-electrode adhesion and the optional annealing step of Bedard would improve electrode wetting by the conductive polymer composition, i.e., improve the adhesion between the conductive polymer composition and the electrode(s) in the electrical devices or self-regulating heaters of that reference from a consideration of Griff and/or Richart. Inasmuch as the contact resistance between the electrode and the conductive polymer composition is affected by the degree of contact or adhesion between these two materials (Bedard, Smith-Johannsen, Gale), one of ordinary skill in the art would have recognized at the time the present invention was made that the degree of adhesion between the electrodes and a conductive polymer composition in the electrical devices or self-regulating heaters of Bedard may be improved by preheating the electrodes to a temperature above the melt temperature of the conductive polymer composition prior to contacting the electrodes with the conductive polymer composition in the extruder as disclosed by Griff and/or Richart. Such a preheating step would have been an obvious alternative to the optional annealing step of Bedard.
Thus, we agree with the examiner's conclusion that one of ordinary skill in the art would have found the subject matter of independent claims 1 and 16 prima facie obvious. The specific electrodes, optional crosslinking step, resistivities, electrode spacing, provision of an electrically insulating composition around the exterior of the extruded product and specific conductive polymer compositions called for by certain of the dependent claims are all disclosed by Bedard. To the extent that certain of the dependent claims require a specific relationship between the conductive polymer coating and the temperature at which the electrode is when the electrode is first contacted by the molten conductive polymer composition, we note that Richart clearly discloses that the metal substrate, here the conductor or electrode, is to be preheated to a temperature above the molten temperature of the polymer to be extruded in order to improve adhesion.
REBUTTAL OF THE PRIMA FACIE CASE
We have carefully considered patent owner's arguments as set forth in the various Briefs submitted on this record and the portions of the declarations which have been made of record in this reexamination proceeding which are relied upon in the Briefs. [FN4] However, it is our conclusion that the arguments and evidence of record on behalf of the patent owner do not provide an adequate rebuttal of the prima facie case.
Patent owner's arguments and evidence provided in support of these arguments presuppose, for the most part, that the electrical devices or self-regulating heaters disclosed in Bedard are annealed. See, e.g., the paragraph bridging pages 12-13 of the Appeal Brief. However, Bedard clearly discloses the annealing step is optional. It is axiomatic that a prior art reference must be considered in its entirety, including nonpreferred embodiments. In re Mills, 470 F.2d 649, 176 USPQ 196 (CCPA 1972).
*7 To the extent Bedard discloses electrical devices or self-regulating heaters which are not annealed, one of ordinary skill in the art would have recognized at the time of the present invention that such devices or heaters may have improved contact resistance due to better adhesion or contact (Bedard, Smith-Johannsen, Gale) if the electrodes are preheated to a temperature above the melting point of the conductive polymer composition from a consideration of Griff and/or Richart. To the extent that Bedard prefers annealed devices or heaters, one of ordinary skill in the art would have recognized from these references that preheating the electrodes to a temperature above the melting point of the conductive polymer composition would be an alternative to such an annealing operation in order to provide enhanced adhesion.
The patent owner argues on pages 15-17 of the Appeal Brief, that the annealed heaters disclosed in Bedard have no areas along the interface where the conductive polymer composition is physically separated and does not contact the electrodes. It is argued that there is such intimate physical contact between the electrodes and the conductive polymer composition in annealed heaters that it is difficult to separate the conductive polymer composition from the electrode. This observation is not surprising inasmuch as Richart discloses that this would be an expected result from such an annealing operation. However, Richart also discloses that the same result may be obtained if one preheats the electrode to a temperature above the melting point of the coating polymer composition prior to contacting the electrode with the molten coating composition instead of an after extrusion annealing process. There is no objective evidence of record that establishes that the contact resistance of an electrical device or self-regulating heater differs unexpectedly when such a device or heater is formed using an annealing step such as in Bedard or using the electrode preheating step taught to be alternative to the annealing step by Richart and used in the present invention. Either step would expectedly result in an electrical device or self-regulated heater which would have better adhesion between the conductive polymer composition and the electrode and, consequently, better contact resistance than such a device or heater which has been formed by a process which does not include annealing or preheating.
The arguments presented on pages 17-20 of the Appeal Brief revolve around Thermon's asserted lack of recognition of the relevance the examiner has placed upon Bedard and Griff in maintaining the rejection of record. Presumably, the same arguments would be advanced in response to our additional reliance upon Smith-Johannsen and Richart. The patent owner argues that Thermon's interest in the outcome of this reexamination proceeding is evidence that these documents are "irrelevant" (Appeal Brief, page 20) to this proceeding since Thermon allegedly did not formulate such a rejection in its reexamination request. The issue before us is whether the subject matter on appeal would have been obvious under 35 USC § 103 to one of ordinary skill at the time this invention was made. We do not find that the authorship of a particular rejection or the relevance placed on a particular disclosure used in support of such a rejection by any specific party to this reexamination proceeding has any bearing on the correctness of the ultimate conclusion reached in the obviousness determination.
*8 The patent owner argues on page 26 of the Appeal Brief that Griff is concerned only with insulated conductors. This is incorrect. As set forth above, Chapter 7 of Griff, which is directed to conventional wire and cable covering techniques, contains a section concerning semi-conductive coatings. Further, Smith-Johannsen explicitly discloses that the electrical devices or self-regulating heaters as in the present invention are extruded in "conventional" fashion. Griff discloses such "conventional" wire coating techniques and specifically discloses that semi-conductive coatings may be extruded on wires using "standard equipment" providing care is taken to avoid excessive shearing. There is no evidence of record that the extrusion equipment used in the prior art or in the present invention is anything but "standard equipment" which is operated in the known and normal fashion for semi-conductive coatings.
It is argued in the paragraph bridging pages 28-29 of the Appeal Brief that the extrusion speeds normally used in extruding conductive polymer compositions are relatively low to avoid shearing of the composition so that problems of premature shrinkage, poor physical properties, lack of adhesion and separation of covering from conductor do not arise. We have carefully considered this argument and the portions of the declarations of record cited on page 29 of the Appeal Brief, but find that they are entitled to little weight. There is no doubt that some degree of adhesion exists between the conductive polymer composition and the electrodes as the electrical devices or self-regulating heaters of Bedard are extruded prior to the optimal annealing step. However, Bedard discloses that the degree of wetting of the electrode by the conductive polymer composition is a matter of concern. Richart discloses that the degree of adhesion in such devices may be improved by either preheating the conductor, as in the present invention, or by annealing the formed product as in Bedard. Either method would expectedly increase whatever degree of adhesion occurs through the normal extruding process. The '339 patent patent discloses that the preheating step of the present invention does, in fact, improve the degree of adhesion of the conductive polymer composition to the electrode over that achieved by the normal extrusion process which does not use an annealing step as evidenced by the pull strength ratios set forth in Examples 4-7. These results would be expected in view of the prior art relied upon herein. The portion of the declarations relied upon by the patent owner in support of this argument do not take this fact into account, i.e., an increase in the adhesion between the conductive polymer composition and the electrode would be expected when the electrode is preheated to a temperature above that of the molten coating.
The patent owner argues on pages 34-36 of the Appeal Brief that Bedard may not be combined with Griff since Griff is not a document within the field of endeavor of the inventors of the '339 patent. As set forth above, the prior art methods of forming the electrical devices or self-regulating heaters of present concern use conventional wire extrusion coating techniques as disclosed in Griff or Richart. One of ordinary skill in the art at the time of the present invention would have readily recognized that the electrical devices or self-regulating heaters of Bedard are formed using such conventional techniques. Therefore, Griff or Richart is within the field of the present inventor's endeavor and is properly combinable with Bedard.
*9 The patent owner argues on pages 37-38 of the Appeal Brief that at the time of the present invention, contact resistance of the prior art devices was not seen to be a significant problem, relying upon, inter alia, the first declaration of Dr. John Meyers, submitted with Paper No. 10, filed January 20, 1988. However, this argument and the declarations relied upon in support indicate that contact resistance is a problem of the prior art devices, albeit not a significant problem. To the extent that contact resistance was perceived to be a problem in the prior art devices, one of ordinary skill in the art would have been motivated to improve it. Further, Dr. Meyers' statements in the relied upon declaration are contradicted by statements in the Gale patent in which Dr. Meyers is listed as a co-inventor. Specifically, Gale discloses that prior art electrical devices, such as self-regulating heaters, had difficulties relating to high contact resistance between the conductors and the PTC material due to the difficulty of achieving metal adhesion to the common PTC materials. These prior art problems persisted up to and including the devices of the Bedard patent. See column 1, lines 32-60 of Gale. This is evidence that contact resistance and lack of adhesion between the electrode(s) and conductive polymer compositions were of concern at the time of Bedard and the present invention.
The patent owner asserts on pages 39-40 of the Appeal Brief that one of ordinary skill in the art would have expected that preheating the conductor as in the present invention would result in the formation of resin-rich layers adjacent the electrodes due to migration of carbon black away from the electrode-polymer interface. We have carefully considered this argument and the supporting evidence relied upon in this portion of the Appeal Brief but find it is entitled to little weight. As explained in Dr. Meyers' second declaration, executed April 19, 1988, this so-called migration theory is based upon the argued phenomenon that the carbon black in the molten conductive polymer composition will migrate away from the preheated electrode, i.e., that as the mass of molten conductive polymer is preferentially cooled the carbon black will migrate towards the cooled surface of the conductive polymer composition, away from the hotter, preheated electrode.
These arguments and supporting declaration do not take into account the precise method which is being claimed in the '339 patent. The claims undergoing reexamination only require that the electrode is to be heated to a temperature above the melting point of the conductive polymer composition which is defined at column 2, lines 49-51 of the '339 patent as the temperature at which the conductive polymer composition begins to melt. The conductive polymer composition in the extruder is molten at the time it contacts the preheated conductor and, therefore, can be at a higher temperature than the electrode. Thus, in the broadest sense, the claims on appeal encompass a set of operating parameters where the electrodes are preheated to a temperature where the conductive polymer composition begins to melt which is a temperature less than the molten conductive polymer composition. According to the so-called migration theory relied upon, this would expectedly result in migration of the carbon black particles in the conductive polymer composition to the interface between the relatively cool electrode and the molten conductive polymer composition, not away as argued. In any event, the argued theory is just that--a theory. There is no objective evidence of record which establishes that the argued phenomenon plays any real role in this process.
*10 The patent owner argues on pages 44-46 of the Appeal Brief that the examiner has combined the prior art for a different purpose than that envisioned by the inventors of the '339 patent and as a result, his rejection under 35 USC § 103 is defective. Reliance is placed upon In re Wright, 848 F.2d 1216, 6 USPQ2d 1959 (Fed.Cir.1988) in support of this argument. Certainly, the problem confronted by the inventors is a factor which must be taken into consideration in making a patentability determination under 35 USC § 103. But that is all that it is, a factor. This factor may be given more or less weight depending upon the total facts of a particular case. It has long been held that a rejection under 35 USC § 103 based upon the combination of references is not deficient solely because the references are combined based upon a reason or technical consideration which is different from that which resulted in the claimed invention. In re Kronig, 539 F.2d 1300, 190 USPQ 425 (CCPA 1976); In re Gershon, 54 CCPA 1066, 372 F.2d 535, 152 USPQ 602 (1967). As established above, the prior art provided ample incentive, reason or motivation to modify the prior art process of forming electrical devices or self-regulating heaters by preheating the conductors or electrodes to a temperature above the melting point of the conductive polymer composition prior to extruding the conductive polymer composition about the conductors or electrodes. Taking into account these teachings of the prior art, we do not find that the inventor's purpose in making the claimed invention is entitled to controlling weight.
The patent owner relies upon the declarations of Mr. Clifford Smith, an employee of Raychem, as evidence of the superiority of the claimed process to the prior art annealing processes. Specific reference is made to paragraphs 6-9 of Mr. Smith's first declaration which accompanied Paper No. 10, filed January 13, 1988.
Mr. Smith sets forth in paragraph 6 of his first declaration that the claimed preheating process is advantageously employed in preference to the old annealing process in part because it eliminates manufacturing steps. Mr. Smith states in paragraph 7 of this declaration that the claimed preheating process results in greater manufacturing predictability and control than was possible with the prior art annealing process.
We conclude, however, that the advantages set forth by Mr. Smith in his declaration concerning the use of a preheating method versus the prior art annealing method would have been expected by one of ordinary skill in the art at the time the present invention was made. We based this conclusion upon the disclosure of Richart at column 3, lines 47-63 that annealing methods, while sometimes more satisfactory than preheating methods, have practical difficulties, i.e., require rather large heating ovens, the coating is exposed to relatively high temperatures for extended periods of times which can result in degradation or other damage to the coating and the difficulty in handling the coated substrate after it leaves the oven until the coating and the substrate have cooled. These practical difficulties of such an annealing method parallel those set forth in Mr. Smith's declaration. One of ordinary skill in the art at the time the present invention was made was aware of these difficulties and would have readily appreciated that these particular difficulties would be avoided when a preheating method such as that disclosed in Richart is used instead. Further one of ordinary skill in the art would have readily perceived that testing the formed product in the annealing method would be difficult due to the bulk of the annealed product and the need to allow the annealed product to cool once removed from the oven, vis-a-vis, the ready availability of the product of the preheating method for testing.
*11 It is argued on pages 53-58 of the Appeal Brief that Thermon failed in repeated attempts to make a self-regulating heater and allegedly copied the present invention when it was disclosed to the public through a French Patent publication which corresponds to the '339 patent. The patent owner cites Panduit Corp. v. Dennison Mfg. Co., 227 USPQ 337 (Fed.Cir.1985), vacated, 475 U.S. 809, 229 USPQ 478 (1986), aff'd on remand, 810 F.2d 1561, 1 USPQ2d 1953 (Fed.Cir.1987) in support. We have carefully considered the evidence relied upon in support of these assertions and find that it is entitled to little weight.
The evidence relied upon as to the purported attempts by Thermon to develop a self-regulating heater consists of isolated excerpts of the depositions of certain Thermon employees taken during the course of the litigation concerning the '339 patent. Due to the ex parte nature of this reexamination proceeding, we have heard only from the patent owner with Thermon not having an opportunity to rebut these allegations. 37 CFR 1.535. Consequently, the record of this reexamination proceeding does not allow this issue to be placed into the context needed in order to determine the correctness of the allegations since it can not be precisely determined what actions were undertaken by Thermon, its purpose in taking any such action and the actual result achieved. See Vandenberg v. Dairy Equipment Co., 740 F.2d 1560, 1567, 224 USPQ 195, 199 (Fed.Cir.1984). Further, as set forth by the court in Cable Electric Products, Inc. v. Genmark, Inc., 770 F.2d 1015, 1028, 226 USPQ 881, 889 (Fed.Cir.1985):
It is our conclusion that more than the mere fact of copying by an accused infringer is needed to make that action significant to a determination of the obviousness issue. Accord Vandenberg v. Dairy Equipment Co., 740 F.2d 1560, 1567, 224 USPQ 195, 199 (Fed.Cir.1984), where copying of a patented device, despite the failure of protracted efforts by the copyist to design a similar device, was found to be an admission of the mechanical superiority of the patented version, but "not strong evidence of nonobviousness." [footnote omitted]
Rather than supporting a conclusion of obviousness, copying could have occurred out of a general lack of concern for patent property, in which case it weighs neither for nor against the nonobviousness of a specific patent. It may have occurred out of contempt for the specific patent in question, only arguably demonstrating obviousness, or for the ability or willingness of the patentee financially or otherwise to enforce the patent right, which would call for deeper inquiry. Even widespread copying could weigh toward opposite conclusions, depending on the attitudes existing toward patent property and the accepted practices in the industry in question. It is simplistic to assert that copying per se should bolster the validity of a patent.
*12 While the allegations of Thermon's copying of the claimed invention and evidence in support thereof are relevant to a patentability determination under § 103, we do not find that on this record, they are entitled to any great weight.
Certain of the dependent claims are argued on pages 59-61 of the Appeal Brief. As to claims 29 through 33 and 36 through 40, we again note that Richart clearly discloses the concept of preheating a substrate to be coated to a temperature above the melting point of the thermoplastic polymer coating. Inasmuch as the specific polymer compositions set forth in these dependent claims are disclosed in Bedard as being suitable thermoplastic polymer coatings for electrical devices or self-regulating heaters, one of ordinary skill in the art would, from a consideration of Richart, choose a suitable temperature based upon a given thermoplastic polymer composition from among those disclosed in Bedard.
It is argued that claims 34 and 41, which require that the conductive polymer should contain 22% or less by weight of carbon black, are unobvious in view of the teaching of Griff that semi-conductive polymers contain 30-50% by weight of carbon black. However, this argument ignores the clear and unambiguous disclosure of Bedard and Smith-Johannsen that semi-conductive coatings used in electrical devices or self-regulating heaters of concern herein may contain less than 15% by weight carbon black. The teachings of Bedard and Smith-Johannsen are more relevant on this point as they are concerned with the devices of the present invention.
The renewed argument concerning the physical state of the interface of the electrode and conductive polymer composition in the electrical device or self-regulating heater of Bedard which appears on pages 5-12 of the Reply Brief and the cited portions of the declarations of record relied upon in support are again based upon annealed heaters. As set forth above, Richart discloses the alternativeness between using a preheating step as in the present invention and an annealing step as in Bedard in order to maximize adhesion between a metal substrate and a thermoplastic polymer composition. Inasmuch as Bedard does disclose that useful electrical devices or self-regulating heaters may be obtained from a method which does not include annealing, one of ordinary skill in the art would have been led to use the pre-heating technique in making such an unannealed heater.
The patent owner argues on pages 9-11 of the Supplemental Reply Brief that if Bedard does suggest the need to improve physical contact at the electrode interface that Bedard itself teaches solutions to this alleged problem and that other prior art documents of record teach a variety of possible solutions to this problem. The patent owner concludes that in view of the variety of alternative solutions to the alleged problem, the examiner's rejection amounts to a so-called "obvious to try" rejection. We disagree.
Assuming arguendo, that the prior art of record suggests the listed alternative techniques to improve adhesion between a metal substrate and a thermoplastic polymer composition, this does not establish that any one of the proposed methods is any less obvious than another. Merck & Co., Inc. v. Biocraft Lab., Inc., 874 F.2d 804, 10 USPQ2d 1843 (Fed.Cir.1989). One of ordinary skill in the art would expect each to work toward improving adhesion to some degree. Indeed, Richart evidences such knowledge on the part of this hypothetical person as Richart discloses at column 2, lines 26-49 the use of primers to achieve better adhesion between a metallic substrate and a thermoplastic polymer coating. As set forth in this portion of Richart, as well as in the portion of the reference which discloses the various methods useful in practicing the invention of that reference, one of ordinary skill in the art recognizes that a given technique of improving adhesion between a metallic substrate and thermoplastic polymer coating will have advantages and disadvantages vis-a-vis any of the other known and obvious alternatives. Richart shows that one of ordinary skill in the art is sufficiently skilled to determine for a given product, e.g., the electrical devices or self-regulating heaters of Bedard, which of the disclosed methods for emphasizing adhesion between the metallic substrate and the thermoplastic polymer coating is best used.
CONCLUSION
*13 Considering anew the evidence relied upon by the patent owner in the various Appeal Briefs in its entirety, it is our judgment that this evidence is not sufficient to outweigh the evidence of obviousness relied upon above. Accordingly, we are in agreement with the examiner's conclusion that the subject matter on appeal would have been prima facie obvious to one of ordinary skill in the art under 35 USC § 103. Inasmuch as we have placed substantial reliance upon Richart and Smith-Johannsen in addition to the Bedard, Griff and Gale references relied upon by the examiner, and since the patent owner's ability to refile is non-existent in a reexamination proceeding, we denominate our affirmance of the examiner's rejection as a new ground of rejection under 37 CFR 1.196(b) in order to provide the patent owner with a full and fair opportunity to respond.
Any request for reconsideration or modification of this decision by the Board of Patent Appeals and Interferences based upon the same record must be filed within one month from the date of the decision (37 CFR 1.197). Should the patent owner elect to have further prosecution before the examiner in response to the new rejection under 37 CFR 1.196(b) by way of amendment or showing of facts, or both, not previously of record, a shortened statutory period for making such response is hereby set to expire two months from the date of this decision.
No time period for taking any subsequent action in connection with this appeal may be extended under 37 CFR 1.136(a). See the final rule notice, 54 F.R. 29548 (July 13, 1989), 1105 O.G. 5 (August 1, 1989).
If the patent owner fails to continue prosecution, the reexamination proceeding will be terminated, and a certificate under 35 U.S.C. 307 and 37 CFR 1.570 will be issued cancelling the patent claims, the rejection of which has been affirmed.
AFFIRMED 37 CFR 1.196(b)
BOARD OF PATENT APPEALS AND INTERFERENCES
James A. Seidleck
Examiner-in-Chief
Henry W. Tarring, II
Examiner-in-Chief
William F. Smith
Examiner-in-Chief
FN1. Counsel stated at oral argument that the civil action between Raychem and Thermon which had been pending in the U.S. District Court for the Western District of Texas, Austin Division, (CA No. A 84 CA 018), has been dismissed without prejudice.
FN2. Patent owner and the examiner agree that the use of the word "setting" at column 3, line 32 of Bedard is a printer's error and that the word "wetting" is correct.
FN3. We recognize that Gale itself is not prior to the claims on appeal. However, it is relevant evidence as to knowledge of those of ordinary skil in the art in the relevant time frame, Ashland Oil, Inc. v. Delta Resins and Refractories, Inc., 776 F.2d 281, 308, 227 USPQ 657, 671 (Fed.Cir.1985); In re Farrenkopf, 713 F.2d 714, 219 USPQ 1 (Fed.Cir.1983).
FN4. Some of the declarations of record and portions of others are directed to rejections and/or references no longer relied upon.
James A. Seidleck, Henry W. Tarring, II and William F. Smith
Examiners-in-Chief
ON REQUEST FOR RECONSIDERATION
*14 Patent owner requests reconsideration of our decision of July 20, 1990, in which we affirmed the examiner's decision that the subject matter on appeal was unpatentable under 35 USC § 103. In reaching our decision, we relied upon Richart and Smith-Johannsen in addition to the Bedard, Griff, and Gale references relied upon by the examiner. [FN1] As stated by patent owner, the present request amounts to a clarification of the number of rejections pending.
There is only one rejection pending. It is under 35 USC § 103 and is based upon the combined disclosures of Bedard, Griff, Gale, Richart, and Smith-Johannsen.
Patent owner's request that the two month period for responding to this rejection be reset is denied as it was not accompanied by any supporting reasons, noting that reexamination proceedings are to be carried out with "special dispatch." 35 USC § 305.
The requested clarification is set forth above. The times for taking any further action with respect to our decision run from the mailing date of our original decision, July 20, 1990.
FN1. Contrary to the statement in the last paragraph of the request, the examiner did rely upon Gale. See page 3, Supplemental Examiner's Answer, mailed August 25, 1989 (Paper No. 40). While this reference is not technically prior art to the claims on appeal, it is relevant evidence that is properly taken into account in the present patentability determination under 35 USC § 103. See the cases cited in footnote 7 of our decision.
August 22, 1990
William F. Smith
Examiner-in-Chief
ERRATUM
The phrase "prima facie" as it appears on page 24, line 15 of our decision mailed July 20, 1990 should be deleted. The sentence should read: "Accordingly, we are in agreement with the examiner's conclusion that the subject matter on appeal would have been obvious to one of ordinary skill in the art under 35 USC § 103."
The times for taking any action with respect to our decision run from the mailing date of our original decision, July 20, 1990.
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