Full opinion text
OPINION STAPLETON, District Judge. These are consolidated actions involving the validity, infringement, ity of United States Patents No. 3,868,434 (“ ’434 patent”) and No. 3,996,311 (“ ’311 patent”), which issued to Richard C. Westphal (“Westphal”) and Paul Heinig (“Heinig”). Cosden Oil and Chemical Company (“Cosden”) originally filed this suit asking for a declaratory judgment that the patents in suit are in valid, unenforceable and not infringed. It has since added allegation of fraud on the Patent Office. American Hoechst Corporation (“AHC”), as successor to Foster Grant Co., the original assignee from Heinig and Westphal, seeks damages and injunctive relief against Cosden for infringement. Jurisdiction and venue are conferred upon this Court by 28 U.S.C. §§ 1338(a), 2201, 2202 and by 28 U.S.C. §§ 1391(a), 1391(b) and 1400(b). This opinion constitutes the Court’s findings of fact and conclusions of law. I. BACKGROUND FACTS Styrene is a “monovinyl aromatic” liquid compound; it contains both an aromatic, or cyclic, substituent and an aliphatic substituent called a “vinyl” group having two carbon atoms connected by a double bond. The presence of this aliphatic double bond makes styrene a chemically reactive monomer which can be polymerized by heat or the addition of a catalyst to form homopolystyrene which has a clear or “crystal” appearance. This so-called “crystal polystyrene” can be molded to form clear plastic products having many desirable properties, such as good moldability, an attractive surface gloss, and good dimensional stability. Unfortunately, crystal polystyrene products suffer from relatively poor resistance to fracture under slight pressure. This characteristic detracts from the use of crystal polystyrene in certain applications and makes it wholly unsuitable for many others. It has long been known that the impact resistance of crystal polystyrene may be improved by adding a small amount of a rubbery material to the styrene either before or after its polymerization. These “rubber toughened” materials are referred to as impact styrene polymer compositions, high impact polystyrene compositions (HIPS), or simply “impact polystyrene,” and are currently used to make hundreds of items ranging from TV cabinets to refrigerator door linings. Concerted efforts were made in the 1940’s to commercialize impact styrene polymer compositions for wider end use applications. The early compositions were made either by dissolving a rubbery matter in styrene monomer and polymerizing the resulting mass, or by simple mechanical blending of the polystyrene and the rubbery material. These manufacturing techniques were well known by 1958 and are very similar to those used today. In the early 1950’s, Amos and his coworkers at the Dow Chemical Company (“Dow”) added a step to the process by “agitating” or stirring the solution of rubbery material in styrene monomer. Agitation was shown to cure the early defect of large insoluble gels in the end products. This was the last significant change in the process; the focus of the industry after 1954 was on improving the compositions themselves by the substitution of new rubbers. The prevailing rubber used by the mid-1950’s was a styrene-butadiene type rubber, “SBR”, which consisted of about 75% butadiene and 25% styrene. In 1956, “stereo-specific polymerization catalysts,” invented by Karl Ziegler, were proved useful in the preparation of “stereoregulated” or “stereospecific” polybutadiene rubbers. These new catalysts made it possible to alter polybutadiene by directing and changing its microstructure. Among the many possibilities which resulted was the “high cis, low vinyl polybutadiene” rubber which was later used to make compositions encompassed by the claims of the patents in suit. “Vinyl” refers to the presence of 1,2-addition butadiene polymer units (called vinyl groups) in which only the first and second carbon atoms of the monomer form the polymer chain backbone, and the third and fourth carbons are in side chains: H H i i i t -- C — C -- i i • i H CH t i t i H -- C — H “Cis” refers to the presence of Cis 1,4-poly-butadiene polymer units, in which the first and fourth carbon atoms are disposed on the same side of a line joining the second and third carbon atoms: H H i i t i ^ -- ^ I I — « 1 H ' ' H H H The presence of these particular molecular configurations in quantities of at least 25% cis 1,4-butadiene, and not more than approximately 10% 1,2-addition butadiene, constitutes a “high cis, low vinyl polybutadiene” for purposes of this Opinion. High cis, low vinyl polybutadiene first became known to the public in 1956 by reference made in a Belgian patent issued to Goodrich Gulf. In 1957, several other foreign patents issued, and an article was published by Short, Kraus and Thornton of the Phillips Rubber Co. (“the Short article”), extolling the virtues of the new material. By 1957, stereospecific rubbers had been sufficiently studied and evaluated that they were being recommended as a substitute for natural rubber in certain applications. About this time, an effort was made in the industry to standardize the impact strength specification for various grades of impact polystyrene. Impact strength was the first property selected, evidently because it represents the most significant improvement over crystal polystyrene. Indeed, this is the property which enabled styrene polymer compositions to be used for a much larger number of products. The Izod impact test, which had been used since the 1920’s to measure fracture resistance, was selected by the industry in 1956-57 to establish representative values for crystal polystyrene and three grades of impact polystyrene (medium, high and super high impact polystyrene). For compositions made using the same type of rubber, the principal difference among the grades of impact polystyrene is determined by the amount of a rubber used in making the composition. The Izod impact strengths provided by high impact styrene polymer compositions made using about 6% SBR rubber were generally about 1 ft-lb/in. notch or less. This is contrasted with crystal polystyrene which has an Izod impact strength of about 0.3 ft-lb/in. notch. In late March, 1958, Mr. Heinig of AHC found a box on his desk. Based on a label and the feel of the material, he concluded that it contained a rubber composition from the Phillips Petroleum Company. While the label contained the words “cis 1,4 polybutadiene”, he did not know its microstructure. The box had been left by a Phillips’ salesperson who had earlier suggested that his company’s new stereospecific rubber should be tried in making impact polystyrene. The material was ultimately determined to be a high cis, low vinyl polybutadiene produced by Phillips. Heinig went immediately to Westphal and instructed him to make impact polystyrene using this material. In April, 1958, Westphal polymerized three specimens of impact polystyrene: one using the Phillips’ polybutadiene at a 6% level, one using a mixture of 3% Phillips’ polybutadiene and 3% SBR 1006, and a “control” specimen using 6% SBR 1006. The three interpolymers were prepared using AHC’s then current process of producing impact polystyrene which involved the sequential addition of two specific catalysts. The first catalyst added was Lupersol # 7 (75% tertiary butyl peracetate). Somewhat later in the polymerization cycle, a second catalyst addition was made, this time with a mixture of Lupersol # 7 and a dissimilar catalyst, di-tertiary butyl peroxide. The two products made using the Phillips’ rubber were described by Westphal and Heinig in their April 16,1958 Memorandum of Invention to exhibit two “disadvantages”: “poor color” and a “slightly slower rate of polymerization,” and one advantage: good impact strength. These are the only advantages or disadvantages disclosed in writing by Westphal and Heinig in their initial Memorandum of Invention in the laboratory records; or in their subsequent memorandum to Leon Horne, then AHC’s in-house patent counsel. There was no reference (comparative or otherwise) in any document prepared in April or May 1958 to the properties of creep yield or gloss. At trial, Mr. Heinig recalled that the gloss of the two products made using the Phillips’ rubber was about the same as the gloss of the SBR-based control. Some additional work was done by AHC during the summer of 1958, when Westphal polymerized three additional impact polystyrene specimens using Phillips’ stereospecific rubber (with its unknown microstructure) at the 2%, 4% and 10% levels. During this time there was substantial correspondence between Mr. Heinig, Dr. Finestone, Heinig’s supervisor, and Mr. Zallen, AHC’s outside patent counsel, who was drafting the first patent application. To define the scope of the “invention” for Mr. Zallen, Heinig and Westphal generalized from a single stereospecific polybutadiene data point. They assumed that the Phillips’ rubber must be one of the stereospecific polybutadienes discussed in the Short article and used that article to predict the cis content range over which stereospecific polybutadiene would enhance the impact strength of polystyrene. Specifically, they obtained the cis range from three places in the Short article, which showed that a lower limit of cis content of 25% was important: (1) a table; (2) a sentence which states that “without exception, the important physical properties change little between 25 and 80% cis content”, and (3) a sentence which states that “[properties of the polymer in the range of 25-80% cis are in some respects reminiscent of emulsion polybutadienes, but are superior to the latter in resilience and low temperature characteristics.” The Short article also disclosed a maximum cis content of 95.2%. Heinig and Westphal admit that they very specifically limited the upper limit of cis content to be used in the claimed “invention” of the 1958 application to 95%. On July 22, 1958, Heinig rewrote the description he earlier provided to Mr. Horne of the experiments conducted in April and May, 1958, to avoid disclosing the sequential addition/dual catalyst system actually employed. His substitute disclosures identified a single catalyst, benzoyl peroxide, with no mention of either the sequential addition system or the two actually-employed catalysts. AHC filed an application for patent in the United States, with Westphal and Heinig named as co-inventors, on September 5, 1958. The application discussed the use of “cis 1,4 polybutadiene” in high impact polystyrene, wherein the end product was made either by (a) polymerizing polybutadiene in styrene or (b) by physically blending the polystyrene and polybutadiene, rather than utilizing chemical “grafting”. The only two rubbery materials referred to in the 1958 application were the SBR control and a stereospecific polybutadiene disclosed as being 80% cis. Each of the three claims recited a cis content of 25-95% and the specification taught that the use of 1,4 polybutadiene having a cis content of 25-95% was essential to the disclosed invention. The application contained no reference to the term “high cis, low vinyl,” but made reference only to “high cis polybutadiene”, “1,4 polybutadiene”, or a combination thereof. While it disclosed polybutadiene with a vinyl content of 1% to 10%, the application contained no statement regarding the significance of the vinyl content, and during the pendency of this 1958 application, AHC made no reference to any importance of vinyl content. Consistent with Mr. Heinig’s inability to find a disclosure of how to make cis 1,4 polybutadiene, there was no disclosure in the application of how to make stereospecific polybutadiene spanning the specified cis content range, except that a reference was made to the use of a “heterogeneous” catalyst system. The application disclosed no “advantageous” properties other than improved impact resistance. During the prosecution of the 1958 application, several events occurred abroad. First, in September, 1960, AHC filed patent applications in France, Canada, Sweden, Australia, West Germany, Great Britain, Japan and the Netherlands. Each of these applications was filed on subject matter common to the subject matter of the 1958 application, by Westphal and Heinig or their representatives or assigns. Second, the French patent application, filed on September 9, 1960, issued to AHC as French Patent 1,273,982 (“the ’982 French patent”) on September 11,1961. AHC was aware of its issuance no later than September 16, 1961. AHC filed its first continuation-in-part application (CIP) on November 27, 1961. This 1961 application disclosed and claimed for the first time that the cis content of polybutadiene within the scope of the invention could be above 95%. The 1961 CIP also claimed for the first time a vinyl content limitation of “not more than about 10%”. The oath accompanying the 1961 CIP application failed to identify any of the foreign applications filed during 1960 or 1961 and erroneously stated that no such foreign applications had been filed. The application also failed to mention that the ’982 French patent had issued. AHC continued to be unsuccessful at the PTO, and rather than appealing the PTO rejection to an ultimate decision, opted to file its second CIP. The second CIP (“the 1965 CIP”) was filed on May 21,1965. This time the accompanying oath or declaration purported to identify AHC’s foreign counterpart applications. However, AHC misstated the filing date of the ’982 French patent. On May 23, 1967, AHC filed its third CIP (“the 1967 CIP”). This application, for the first time, disclosed the allegedly unexpected properties of improved gloss and creep yield. The 1967 CIP, which eventually issued as the ’434 patent, was appealed to the PTO Board of Appeals three times. In 1969, the Board affirmed the Examiner’s rejection of all claims, holding that the use of the claimed polybutadiene for improved impact in impact polystyrene was prima facie obvious and that AHC’s showing of a single comparative data point for each of creep yield and gloss was inadequate to rebut this presumption. On the next appeal in 1973, the case was remanded for further consideration of art not cited by the. Examiner and for reevaluation in view of a new CCPA decision. On the third appeal, the Board of Appeals concurred with the Examiner that the claimed subject matter was prima facie obvious. In the course of its decision, the Board of Appeals held that the 1958 application did not support claims covering more than 95% cis: We find that the 1958 application is very clear, in presenting an upper limitation of 95% cis 1,4 polybutadiene as well as a disclosure of 1-10% 1,2-addition butadiene content for the mixture. We are not convinced by the affidavits presented in support of appellants’ position. (COS 696, p. 970). However, the Board reversed the Examiner, holding that AHC’s Rule 132 affidavits showing improvements in creep yield and gloss rebutted the showing of prima facie obviousness and rendered the subject matter patentable. As a result, the ’434 patent issued. On October 29,1971, AHC filed its fourth CIP, which was prosecuted simultaneously with the 1967 CIP. The claims of the 1967 CIP differed from those of the 1971 CIP in that the 1967 CIP contained certain additional process limitations as to the manner of forming the polymer compositions which were not recited in the 1971 CIP. AHC told the PTO that [a]ll of the claims in the parent application Serial No. 640,478 [the 1967 application] require that the composition be made by mass polymerization. The claims on appeal do not define any mass polymerization limitation. The claims in the parent application state that the rubber component must be dissolved in the styrene monomer. No such limitation appears in the claims presently on appeal. (COS 696). These two process distinctions represent the only substantive differences between the claims of the ’434 patent and the ’311 patent. This application, too, was rejected several times, was appealed, and then abandoned in favor of a still further CIP. The fifth and last CIP was filed on February 24, 1975, and eventually resulted in the ’311 patent, which was issued on December 7, 1976. II. INFRINGEMENT Since the issuance of the ’434 patent in February, 1975, Cosden has made and sold moldable impact styrene polymer compositions using Diene 35, Diene 55 and Taktene polybutadienes. Its use of Diene 35 and Diene 55 polybutadiene to make such compositions continues to the present. These compositions are made by dissolving about 5-10% of Diene or Taktene polybutadiene in styrene and polymerizing the styrene monomer under free-radical polymerization conditions until polymerization of the styrene monomer is substantially complete. Cos-den’s polymerization is carried out using mass polymerization techniques under agitation conditions to provide dispersed and substantially uniform compositions having enhanced impact value. Having so found, only two infringement issues remain: (1) is the vinyl content of the Diene polybutadiene “not more than about 10%” and its cis content “at least 25%”; and (2) is the cis content of the Taktene polybutadiene about 95% and its vinyl content “not more than about 10%”. AHC’s experts, Dr. Wiles and Professor Levy, analyzed six samples of Diene polybutadiene secured from Cosden and represented by it to be the material used in making its styrene polymer compositions. The vinyl contents of those samples, as measured by Dr. Wiles, were 8.6, 8.8, 8.5, 8.6, 8.6 and 8.5% and, as measured by Professor Levy, were 8.6, 8.3, 8.7, 8.5, 8.5 and 8.9%. Those measurements are in close conformity with the values published by Firestone throughout the years for the vinyl content of Diene polybutadiene of 7.5% and 9.1 or 9.4% They are also relatively close to the measurements of Cosden’s expert, Dr. Koenig, when he analyzed six samples of commercial Diene polybutadiene: 10.7, 10.8, 10.7, 10.8 and 10.8%. Dr. Wiles values for the cis content of the six samples which he analyzed were 33.9, 34.5, 33.9, 33.9, 33.9 and 33.7%. Firestone’s published value for the cis content is 35.9%. Dr. Koenig’s figures were 37.7, 38.1, 37.6, 37.8, 37.5, 37.7%. With respect to Taktene, Dr. Wiles found a cis content in two samples of 96.6 and 96.8% and a vinyl content of 1.4% and 1.3%. Professor Levy analyzed for vinyl content only and obtained values of 2.8% and 1.5%. Cosden submitted no test data for Taktene. Based upon the Wiles and Levy data, I conclude that the Diene polybutadiene used by Cosden has a vinyl content of “not more than about 10%” and a cis content of “at least 25%”. I also conclude that the Taktene used by Cosden has a cis content of “about 95%” and a vinyl content of “not more than about 10%”. I accept the data referenced above because it is the product of careful and skilled analysis and because each analysis seems internally consistent as well as confirmatory of the others. I discount the attacks made by Cosden on this data for reasons I will summarize below. Initially, Cosden argues that the analyses done by Levy and Wiles should be disregarded because their respective methods of measurements were allegedly not practiced in the Spring of 1958, when the invention was conceived. Levy conducted nuclear magnetic resonance (“NMR”) analyses, which concededly were not available in 1958, to determine microstructure as called for in the patent claims. Wiles used infrared (“IR”) spectroscopy which was well-known in 1958 but which, according to Cos-den, was practiced at that time only in ways which differ materially from those used here. I do not adopt Cosden’s position on this point because I disagree with both its legal premise and its analysis of the record. I agree that the state of the art of measurement in a particular field may be highly relevant in construing a patent and determining the scope of its claims. The statute charges the applicant with communicating his invention to those skilled in the art and his teachings are to be understood in light of the art as it then existed. In determining the boundaries of “not more than about 10%”, for example, it is helpful to know the margin of error in the measurement techniques of the day. If those in the art are aware that the margin of measurement error is plus or minus 5%, it is unlikely that they would read “not more than about 10%” to exclude anything below 10.5%, and quite likely that they would read it to include a somewhat higher limit. But using the existing state of the art to determine the scope of the claims of a patent is something quite different from limiting proof of infringement to methods in existence on the date of invention. If the scope is determined in the context of the existing art, I perceive no advantage and considerable mischief in freezing measurement technology and disregarding new learning which can establish, almost beyond peradventure, the precise characteristics of the accused substance. I do not believe the law so requires. Moreover, I do not believe Dr. Wiles’ technique differed materially from the varying techniques reflected in the literature in the late 50’s and early 60’s. Indeed, he followed a technique described in a 1949 publication. As one would expect, those practicing IR spectroscopy at that time had various preferences about the best technique to follow. At least one of these preferences even led some astray for a short time; but it is not true in any practical sense that Dr. Wiles’ IR analysis was not the kind of analysis being conducted in 1958. Indeed, Dr. Hampton, a pioneer in the field, indicated that Dr. Wiles’ method of analysis was the only one being used in 1958. He testified that, while varying techniques would produce somewhat varying results, most skilled artisans were using the same method and were achieving substantially the same results, with an error rate in the neighborhood of plus or minus 5%. Cosden does not seriously challenge Professor Levy’s results other than on the ground that his method was too modern. Dr. Wiles, however, is said to have made three “critical errors”: (1) his use of iodine monochloride titration, (2) his calculated recovery of only 90 to 92% polybutadiene of the Diene samples which he analyzed and (3) his application of an iteration technique to calculate extinction coefficients. I find no fault with Dr. Wiles’ titration method; his data show that the reproducibility obtained was good and the precipitation which occurred was “during the titration”, not “during the reaction.” With respect to the finding of 90% unsaturation in the vinyl standard, both Hampton and Wiles testified that this would only lead one to infer that the sample was not pure polybutadiene and would cast no doubt on Wiles’ results. Finally, the iteration technique used by Wiles was that taught by Hampton, and followed by Silas, Morero and Gevers. III. VALIDITY A. The Threshold Issues. At the outset, three related issues will be considered. The first issue is the earliest filing date to which AHC is entitled under 35 U.S.C. § 120. The second issue is whether AHC complied with 35 U.S.C. § 112 in connection with the various applications leading up to the patents-in-suit. The third issue is whether AHC made an invention or discovery prior to 1967, when it for the first time disclosed the allegedly improved properties of gloss and creep yield which were the predicate for the issuance of the patents. 1. 35 U.S.C. § 120. 35 U.S.C. § 120 allows a later-filed application, under specified circumstances, to claim the benefit of one or more earlier-filed applications. It is well established that to come within the purview of Section 120, (1) a later application must, inter alia, disclose the same invention as has previously been disclosed in each prior application, and (2) each application must comply with 35 U.S.C. § 112. See, e.g., 35 U.S.C. § 120; Acme Highway Products Corp. v. D.S. Brown Co., 431 F.2d 1074, 1078 (6th Cir. 1970), cert. denied, 401 U.S. 956, 91 S.Ct. 977, 28 L.Ed.2d 239 (1971); Bendix Corp. v. Balax, Inc., 421 F.2d 809, 816-17 (7th Cir. 1970), cert. denied, 399 U.S. 911, 90 S.Ct. 2203, 26 L.Ed.2d 562 (1979), reh. denied, 414 U.S. 819, 94 S.Ct. 43, 38 L.Ed.2d 51 (1973); Chromalloy American Corp. v. Alloy Surfaces Co., 339 F.Supp. 859, 874 (D.Del.1972). None of the claims of the patents-in-suit which claim a cis content range of 25 to 100% is entitled to a 1958 filing date because the invention in the patents differs from the invention described in the 1958 application and is the result of changes made in the 1961 CIP. There was a crucial difference between the descriptions of the invention set forth, respectively, in the 1958 application and the 1961 CIP concerning the maximum cis content of the polybutadiene to be used in the “invention”: 1958 Application “The invention comprises essentially a. composition comprising 80-99% of the vinyl aromatic polymer and 1-20% total rubber material, wherein the composition contains at least 1% of a 1,4 polybutadiene having a cis-polymer percentage of 25-95% of the total polymer forms present.” (COS 696 [58], pp. 1-2). (Emphasis added). 1961CIP “The invention comprises essentially a product comprising 80-99% of a vinyl aromatic material and 20-1% total rubbery materials, said rubbery materials comprising (a) at least 1% by weight of the total product of a 1,4 polybutadiene having a cis content of at least 25% and a vinyl or 1,2 addition content of not more than 10%. . . ." (COS 696 [61], p. 19). (Emphasis added). This distinction between the effective maximum cis content of polybutadiene within the invention disclosed in the 1958 application and that disclosed in the 1961 CIP is also evident from a second comparison between the two applications: 1958 Application “Only when at least 1% of total rubbery content of the composition consists of a 1,4 polybutadiene having 25-95% cis polymer content are the improvements of this invention obtained.” (COS 696 [58], p. 3). (Emphasis added.) 1961CIP “Only when at least 1% of the total rubbery content of the composition consists of a 1,4 polybutadiene having a cis content of at least 25% and a vinyl content of not more than 10% are the improvements of this invention obtained.” (COS 696 [61], p. 21). (Emphasis added). AHC, in 1958, twice described the necessity to the invention of using 1,4 polybutadiene with a cis polymer content of 25-95%, and each of the claims of the 1958 application precisely tracked this microstructure range. In view of these contrasting descriptions of the invention, it is apparent that in 1958, 1,4 polybutadiene having less than 25% cis content or having more than 95% cis content was excluded from the impact polystyrene invention. The specification is unambiguous. As earlier noted, the PTO Board of Appeals so held in ruling that the 1958 application did not support the claims which included the 95-100% range. Not only are objective descriptions of the 1958 invention not the same as the 1961 invention, but it also was AHC’s subjective intention in 1958 to so-limit the invention. Westphal and Heinig admitted that AHC purposefully and deliberately limited the invention in 1958 to 1,4 polybutadiene having a maximum cis content of 95% and AHC’s contemporaneous documents confirm that, in 1961, AHC management believed the 1958 application was so-limited. Thus, the 1958 application clearly was not intended to encompass the use of a 1,4 polybutadiene having greater than 95% cis content and, contrary to AHC’s contention, in the context of that application, one of ordinary skill in the art would not read the disclosure of “typical cis polybutadienes having compositions substantially in the range 25-95% cis” as teaching the use of polybutadiene having a cis content in excess of 95%. It follows that all claims covering a cis content range of 25-100% are not entitled to an effective filing date prior to November 27, 1961, the first time such an invention was disclosed within the meaning of Section 120. 2. 85 U.S.C. § 112. The first paragraph of 35 U.S.C. § 112 concludes with the requirement that the patent specification “. .. shall set forth the best mode contemplated by the inventor of carrying out his invention.” The “purpose of this ... requirement is to restrain inventors from applying for patents while at the same time concealing from the public preferred embodiments of the inventions which they have in fact conceived.” In re Gay, 309 F.2d 769, 772, 50 Cust. & PatApp. 725 (1962). At the time of the filing of the 1958 application, AHC was utilizing a sequential addition/dual catalyst system in which Lupersol No. 7 and di-tertiary butyl peroxide were added in two stages. This was considered to be “proprietary information”, in Mr. Heinig’s words, however, and Example 1 of the 1958 application, and all subsequent applications, referred to a single addition of benzoyl peroxide as a catalyst. This was done because AHC believed the process for making high impact polystyrene which involved the two step technique had commercial value. It does not follow, however, that the 1958 application violated Section 112. The requirement is of disclosure of the best mode of carrying out the invention and the character of the claimed invention must be kept in mind in applying this section. The alleged invention of Westphal and Heinig was a composition, not a process. Consequently, all claims of both patents in suit are directed to styrene polymer compositions, not to the method or process of making such compositions. The best styrene polymer compositions known to the inventors at the time they filed their 1958 application were fully disclosed in that application, and contrary to Cosden’s assertions, nothing in this record establishes that the process described in Example 1 produces a composition which is in any way inferior to compositions made with the sequential addition/dual catalyst system being used by AHC in 1958 in its commercial production. The first paragraph of Section 112 also required a patent applicant to disclose his invention “in such full, clear, concise, and exact terms as to enable any person skilled in the art ... to make and use the same.... ” Cosden asserts that the 1958 application of Westphal and Heinig failed to comply with this enablement requirement and that AHC is, therefore, not entitled to rely upon that application for its priority date with respect to the prior art. Cosden’s primary argument is that the 1958 application (as well as the subsequent applications of Westphal and Heinig) should have specified an analytical technique for determining the microstructure of the polybutadiene used in making the disclosed compositions. As earlier indicated, I am not persuaded that there were numerous measurement technologies in 1958 which would produce materially different results. There was one technology — infrared spectroscopy — and there was no need to tell one skilled in the art what technology to use in determining microstructure. Contrary to Dr. Koenig’s assertion, Mr. Hampton testified that, if a sample of polybutadiene had been cut up into small pieces and sent to different people skilled in the art of infrared analysis in 1958, the competent spectroscopists should have obtained similar microstrueture values. The fact that individual practitioners of infrared spectroscopy may have had individual preferences in technique for practicing the art did not mean that the 1958 application was inadequate for failing to name some particular practitioner. Cosden also faults AHC for failing to specify certain process conditions in the patent which can affect the quality of the resulting product. The “process conditions” necessary to practice the invention, however, were the conventional processes already known to those skilled in the art by virtue of their disclosure in prior art patents and publications. Lever Bros. Co. v. Proctor & Gamble Mfg. Co., 139 F.2d 633, 638-39 (4th Cir. 1944). While conditions such as stirrer speed were shown to have an impact on the properties of the high impact polystyrene, there is no evidence that any special process conditions were required to obtain the advantages of the invention. Finally, Cosden contends that the patent fails to comply with Section 112 because it was issued on the basis of allegedly superior and unexpected properties for impact polystyrene over a critical polybutadiene microstructure range, which is not critical in fact. In support of this argument, Cosden relies heavily on the holding of Kwik Set, Inc. v. Welch Grape Juice Co., 86 F.2d 945 (2d Cir. 1936) that: A patentee may not arbitrarily select a point in a progressive change and maintain a patent monopoly for all operations in that progressive change falling on one particular side of that arbitrarily selected point. It is only where the selected point corresponds with the physical phenomenon and the patentee has discovered the point at which that physical phenomenon occurs that the maintenance of a patent monopoly is admissible.... Id. at 947. I think it apparent from the record that “no more than about 10%” vinyl is not a point at which a distinctive physical phenomenon occurs in the sense that the results on one side of that point are materially different from the results immediately on the other. Indeed, AHC does not argue that “about 10%” is a “go/no go” point. Such a finding is not necessary to patentability, however. Assuming that properties throughout the claimed range are markedly better than the properties of the prior art so that the inventor has indeed described how to get a composition substantially superior to prior art compositions, a point addressed hereafter, it should make no difference under Section 112 if the results somewhat above 10% are also substantially superior to the prior art. In that event, the applicant would have satisfied the requirements of Section 112 even though he may have claimed a monopoly of more limited scope than the one to which he was entitled. 3. 35 U.S.C. § 101. Section 101 of the Patent Act provides that one who “invents or discovers” a new composition shall be entitled to a patent. Cosden argues that AHC is not entitled to the 1958 filing date because Heinig and Westphal had not discovered the alleged invention as of that time. It points out that the patent was issued solely on the basis of the allegedly unexpected properties of improved creep and gloss and that the first mention of these properties came in the 1967 CIP. While the argument is not without appeal, I believe the issue is no longer open in the Third Circuit. Assuming for the moment that these improvements are characteristic of the claimed compositions, neither the failure to expressly mention them in the 1958 application, nor, indeed, the failure of the inventors to appreciate the improvements at that time would operate to bar AHC from relying on the 1958 filing date. Eli Lilly and Co. v. Premo Pharmaceutical Laboratories, Inc., 630 F.2d 120 (3d Cir.), cert. denied, 449 U.S. 1014,101 S.Ct. 573, 66 L.Ed.2d 473 (1980); In re Davies, 475 F.2d 667 (Cust. & Pat.App. 1973). B. Anticipation 1. Shell’s Work. Section 102(g) stipulates that one is not entitled to a patent if “before the applicant’s invention thereof, the invention was made in this country by another who has not abandoned, suppressed or concealed it.” Citing this Section, Cosden asserts that AHC is not entitled to a patent on any claims reciting a cis content in excess of 95% because workers at Shell had earlier conceived of that invention and reduced it to practice. (a) AHC’s Experience With Very High Cis Polybutadiene. I have previously concluded that the 1958 patent application did not claim or disclose impact polystyrene made with very high cis polybutadiene (i.e., polybutadiene having a cis content in excess of 95%). As a result, AHC cannot claim a filing date or constructive reduction to practice with respect to the claims including this range until November 27, 1961. AHC nevertheless asserts, however, that Westphal and Heinig conceived of using very high cis polybutadiene in April of 1958 and reduced that conception to practice at least by November of 1960. In evaluating this claim, one must keep in mind the principles recently reviewed by Judge Schwartz in Grefco, Inc. v. Kewanee Industries, Inc., 499 F.Supp. 844, 848 (Del.1980): The date of invention is deemed to be the date of the filing of the patent application. U.S. Expansion Bolt Co. v. Jordan Industries, Inc., 488 F.2d 566, 568 n. 3 (3d Cir. 1973). The burden rests with the inventor to demonstrate an invention or reduction to practice prior to the time of filing. See generally Rex Chainbelt Inc. v. Borg-Warner Corp., 477 F.2d 481, 487 (7th Cir. 1973); 1 Chisum, Patents § 3.08[3]; United Show [Shoe] Machine Corp. v. Brooklyn Wood Heel Corp., 77 F.2d 263 (2d Cir. 1935). Moreover, the uncorroborated and undocumented testimony of the patentee is insufficient to prove invention date. Westphal and Heinig each testified that they conceived of making polystyrene with very high cis polybutadiene in April of 1958, but that they failed to mention this conception in the 1958 application because their patent counsel, Mr. Zallen, had advised that there should be no reference to a polybutadiene which they had no reason to believe had actually been produced. There is no corroboration of this testimony, however, and, based on all of the evidence, I conclude that it is, at least in part, post hoc rationalization. Westphal and Heinig did not know the microstructure of the Phillips polybutadiene when they used it to make polystyrene and their memorandum of invention makes no mention of microstrueture. Moreover, there is no mention of microstructure in Westphal’s laboratory notebook or in the research department summaries between April and July 1958. At some point prior to the September 1958 filing, Westphal and Heinig were exposed to the microstructure information in the Short article, however, and the range claimed in the 1958 application was a guess based on the microstructure there reported. That article makes no reference to a polybutadiene having a cis content in excess of 95%. Nor is there any such reference in any of the drafts of the 1958 patent application or in any of the communications between Westphal and Heinig and their patent counsel. We do know that, in June of 1958, AHC, and I believe it fair to infer Westphal and Heinig, were aware of the possibility that one could produce a 98% cis polybutadiene with stereospecific catalysts. Dr. Finestone at AHC wrote a letter to Mr. Zallen on June 25, 1958 so stating. Moreover, I can accept that Westphal and Heinig believed in the summer of 1958 that one could make an impact polystyrene with very high cis polybutadiene. After all, they had no reason to believe otherwise. On the other hand, the record as a whole indicates that they did not believe at the time of filing the application that one would get markedly improved impact strength, much less improved gloss and creep yield, in polystyrene made with very high cis polybutadiene. Their sole basis for conceiving that any polybutadiene, other than the Phillips’ sample, would produce improved results was the Short article which they used to formulate a guess on the range throughout which improved results would be achieved. Accordingly, the most rational inference from all the evidence is that they did not formulate the conception in 1958 that very high cis polybutadiene would give improved results. This situation appears to have continued until May of 1961 when AHC received a sample of 99% cis polybutadiene and used it to make impact polystyrene with improved results. While AHC repeatedly sought samples of high cis polybutadiene from rubber companies between September 1958 and May 1961, no reference is made to very high cis polybutadiene and the evidence concerning this period provides no basis for concluding that Westphal’s and Heinig’s appreciation for the potential of that material increased in any way. (b) Shell's Experience With Very High Cis Polybutadiene. At some time prior to November, 1957, Lunk, Schroeder and Doyle at Shell conceived of using very high cis polybutadiene as a toughening agent for making impact polystyrene. The testimony of the inventors to this effect was corroborated by three employees of Shell at the time, as well as by documentary evidence. Dr. Lunk’s laboratory notebook, which described in detail experiments run in November 1957 and January-February 1958 using a 98.6% cis, .6% trans, and .8% vinyl polybutadiene, confirms that these Shell workers had the concept of very high cis polystyrene in mind as of November 1957 and that they in fact made polystyrene with that polybutadiene on several different occasions prior to April of 1958. Only a single sample of very high cis polybutadiene rubber made at Shell was available to Lunk, Schroeder and Doyle during the 1957-58 winter. The November 1957 polymerization was not stirred. It showed an impact strength of 1.40 and 2.2 foot per pound per inch at the 3% and 4% rubber levels respectively. In December, Shell began making stirred polymerizations in accordance with the teachings of the Amos patent. The next three polymerizations with very high cis polybutadiene, conducted in January and February 1958, accordingly, were stirred. The January 1958 runs were carried out at the 3% and 4% levels. The 3% run, a relatively low rubber level, showed impact strength of .96 ft./lbs. per inch; the 4% run showed a rather modest impact, .58 and .66 ft./lbs. per inch. In February 1958, the same rubber was again run at the 4% level. It showed impact strengths of 1.21 and 1.46 ft./lbs. per inch. With the exception of the one 4% run in January 1958, which apparently was over-agitated, those impact results were substantially higher than Shell was contemporaneously achieving with SBR at comparable rubber levels. The November and February results at the 4% level were also better than those achieved by AHC at that level several months later with 95% cis polybutadiene. Shell’s work with very high cis polybutadiene was done with the expectation that it might produce a polystyrene with improved impact strength and Shell’s experiments prior to April 1958 show that such a result was in fact achieved. The record affirmatively establishes, however, that the workers at Shell did not appreciate during that period of time that the improved results were attributable to the very high cis polybutadiene. The Shell monthly research reports do not report at all on the November 1957 to February 1958 work. Moreover, the January 1959 research report affirmatively concluded as follows: Although properties similar to those obtained with S-1006 [i.e. SBR] were obtained with some experimental materials such as emulsion polybutadiene, and cis polybutadiene, none of these materials gave products superior to those from S-1006. Availability and ease of handling are other and perhaps not unimportant, factors in favor of S-1006. A June 1959 report does show, however, that the Shell workers appreciated the connection between very high cis polybutadiene and higher impact strength by that time. In that publication, Lunk and Schroeder reported as follows: Several types of cis-polybutadiene, differing in molecular weight and micro-structure, have been investigated in the preparation of high impact polystyrene via bulk interpolymerization. Compared with SBR rubbers (i.e., S-1006) they showed the following advantages: (1) Higher impact strength and elongation. At a rubber concentration of 5%, impact strengths of 1.5-2 ft. lb/in. were obtained, as compared to 0.9-1.2 ft. lb/in. with S-1006. The improvements in elongation were less spectacular but still substantial. (2) Better resistance to high temperatures during the polymeriation reaction. With S-1006, considerable losses of impact strength and elongation occurred when the final temperature of the polymerization reaction was higher than 180° C. Interpolymers containing cis-polybutadiene suffered little or no losses at temperatures as high as 195° C. (c) Analysis. Whether or not there can be a conception of an invention without an appreciation by the inventor of unexpected, inherent properties which alone support its patentability has been a matter of some debate. I need not resolve that issue here, however, because under either view, Cosden prevails on its contention that Shell’s work anticipates those claims of the patent-in-suit which include very high cis polybutadiene. If appreciation is not required, the evidence clearly and convincingly demonstrates that Shell both conceived this invention and reduced it to practice in the winter of 1957-58 before Heinig and Westphal received the Phillips sample. If appreciation is required, the record clearly and convincingly establishes that Shell had both conceived it and reduced it to practice on or before June 1959, while there is nothing in the record to support conception or actual reduction by AHC prior to May of 1961. It follows that, under Section 102(g), all claims including the cis range over 95% are invalid unless it can be said that Shell “abandoned, suppressed or concealed” its invention. Clearly, it cannot. On January 25, 1960, Shell filed a United States patent application in the names of Lunk, Schroeder and Doyle covering the use of polybutadiene having a cis content above 90%, and preferably about 95%, as the toughening agent for making impact polystyrene, the subject matter of that application was carried forward in successive continuation-in-part applications for the next fourteen i years until the last application in the chain was ultimately abandoned in 1974. AHC argues that this abandonment of the last patent application filed by Lunk, Schroeder and Doyle is evidence of abandonment of their 1957-1958 work. I disagree. The fourteen years work in attempting to secure patent protection provides more support for the conclusion that there was no intent to abandon, than the ultimate cessation of those unsuccessful efforts provides for a contrary conclusion. See Jacquard Knitting Mach. Co., Inc. v. Ordinance Gauge Co., 213 F.2d 503, 508 (3d Cir. 1954). Moreover, even if Shell had abandoned its invention in 1974, it would not help AHC since the relevant legal issue is whether there had been an abandonment as of 1961. Allen v. W.H. Brady Co., 508 F.2d 64 (7th Cir. 1974); Continental Copper and Steel Industries, Inc., 196 U.S.P.Q. 30, 37 (M.D. Pa.1976). With respect to concealment and suppression, AHC contends that notebooks, records and reports relating to the work of Lunk, Schroeder and Doyle have never been made available to the public by Shell and that the abandoned patent application continued to be inaccessible to the public because of the PTO’s policy of confidentiality set forth in 37 C.F.R. § 1.14. Although many of Shell’s internal corporate documents and laboratory records have not been made available to the public, this does not support an inference of “suppression or concealment.” And, as far as the public availability of Shell’s abandoned patent application is concerned, reference to that application in the Lunk T99 patent is sufficient to render it available to the public as of its January, 1964 issue date. In re Lund, 376 F.2d 982, 991, 54 Oust. & Pat. App. 1361 (1967); 37 C.F.R. 1.14(b). Like abandonment, suppression or concealment must be intentional. English v. Heredero, 200 U.S.P.Q. 597, 600 (Bd.Pat. Interf.1978). Shell spent fourteen years trying to get a U.S. patent. It disclosed the Lunk, Schroeder and Doyle work in another U.S. patent to Lunk, which did issue. The work was also described in ten foreign published patent applications. All three inventors and their patent counsel testified that there was never, at any time, an intent to suppress or conceal the Lunk, Schroeder, Doyle work. The evidence is thus inconsistent with an intent to suppress or conceal. 2. The Amos ’692 Patent. The Amos ’692 patent, in Example 6, taught a polystyrene composition obtained by polymerizing styrene monomer in the presence of a solution polymerized polybutadiene. Dr. Bucknell, Cosden’s expert, explained that the cis content of this polybutadiene was in the range of 25% and the vinyl content was in the range of 18.5%. This is consistent with the data which AHC provided to the patent office. Cosden maintains that the 10% vinyl content limitations of the patents-in-suit is not “material” and that Example 6 of the Amos patent meets every other limitation of the patents-in-suit. In addition to maintaining that the 10% vinyl limitation is material, AHC points out that Claims 1, 3-14, and 27 of the ’131 require a graft interpolymer of styrene and 1,4 polybutadiene, while Claims 1, 3-14 of that patent specify that the composition must contain a discontinuous phase which is substantially insoluble in toluene at room temperature. These latter two limitations do not distinguish Amos, however. Amos clearly taught graft copolymers as well as linear polymers. With respect to solubility, the Amos ’692 patent did not discuss whether the discontinuous phase of the impact polystyrene product was soluble or not. It dealt with the product as a whole. It appears, however, that the discontinuous phase of Amos is substantially insoluble. I agree with AHC and the PTO, however, that the 10% vinyl limitation satisfactorily distinguishes the Amos ’692 patent. 3. The Schramm ’227 Patent; The Lunk '199 Patent; and the ’982 French Patent. Cosden cites the Schramm ’277 patent; the Lunk ’199 patent; and the ’982 French patent as anticipations of the claims of the patents-in-suit that include the 95% to 100% range. Having reached the conclusion I reached on the Section 102(g), I need not decide these issues. C. Obviousness. For an invention to be held unpatentable under Section 103 of the Patent Act, it must be found that the differences between the invention and the prior art are such that the subject matter of the invention as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art. Clopay Corp. v. Blessings Corp., 422 F.Supp. 1312 (D.Del.1976). The pertinent art in the context of this case is the commercial production of high impact polystyrene and the development of improved forms thereof. The record indicates that, as of September 1958 and at all times here pertinent, the persons skilled in this art were employed by major chemical companies, like Monsanto and Dow, which were the principal competitors in the impact polystyrene market. These firms employed groups of people who had specific responsibility for developing impact polystyrene with improved properties. They were thus “problem solvers”. See, e.g., Systematic Tool & Machine Co. v. Walter Kidde & Co., Inc., 555 F.2d 342 (3d Cir.), cert. denied, 434 U.S. 857, 98 S.Ct. 178, 54 L.Ed.2d 128 (1977); Komline-Sanderson Eng. Corp. v. Ingersoll Rand, 485 F.Supp. 973 (D.Del.), aff’d 639 F.2d 773 (3d Cir. 1980). Typically, these groups would include someone with post-graduate work in chemistry, as well as others with less formal education but many years of practical experience in this or related arts. Whatever the mix of education and on-the-job training, however, it is fair to characterize the members of these groups as well informed and highly skilled in the art. As AHC readily concedes, it was well known in the art in September of 1958 that the impact properties of polystyrene could be enhanced by polymerizing the styrene monomer in the presence of rubbery polymers. The process customarily used at that time for accomplishing this objective was that described in the Amos ’692 patent. Amos taught that the rubber should be dissolved in styrene monomer and stirred until it became a suitable prepolymer; the prepolymer was then placed in the second vessel where the polymerization would be completed. Amos also taught that polybutadiene was one of the rubbery modifiers which could be used in this way to “toughen” polystyrene. In particular, his example 6 described an experiment using a polybutadiene prepared by free radical polymerization. Amos does not specify the microstructure of the polybutadiene, but one skilled in the art would realize from his description of its preparation that it had a microstructure of about 25% cis and about 18% vinyl. This microstructure is, of course, quite close to that of polybutadienes included within the microstructure range referred to in the claims-in-suit and it seems clear that one skilled in the art would understand from Amos that impact polystyrene could be made with polybutadienes within the claimed range. Amos did not suggest, however, that higher cis (i.e., over 25%), lower vinyl (i.e., not more than about 10%) polybutadienes would produce a more desirable product than other polybutadienes or than prior art SBR rubber. AHC further concedes that one skilled in the art in September of 1958 would know that emulsion polybutadiene, typically having a cis content of about 20% and a vinyl content of about 18%, could be used to toughen polystyrene. The teaching that emulsion polybutadiene could be utilized in making impact polystyrene is said by AHC to be the closest prior art. High cis, low vinyl polybutadienes coming within the microstructure range cited in the patents in suit had been produced using stereospecific catalysts well prior to April of 1958. The Smith, et al patent, a Phillips patent filed in April of 1956, for example, disclosed a cis 4-type polybutadiene of generally high cis content. The Foster patent, a Firestone patent filed in August of 1956, disclosed the Diene type polybutadienes, of generally low to medium cis content. By October of 1957, Phillips had had an opportunity to do some in depth study of the characteristics of the new stereospecific polybutadienes. The Short article was published in that month This article considered the effect of changes in the cis content on the physical properties of polybutadienes prepared with stereospecific catalysts systems and compared the properties of these compositions with those of emulsion polybutadiene and SBR. Short concluded that the high cis polybutadienes had “excellent resilience”, and that the properties of polymers in the range of 25-80% cis “are in some respects reminiscent of emulsion polybutadiene but are superior to the latter in resilience and low temperature characteristics.” Short also explained that a comparison of the stereospecific product with natural rubber and SBR revealed a “marked superiority of 1,4 polybutadiene at low temperatures.” Neither Short nor any other prior art reference suggested that if one polymerized styrene monomer in the presence of high cis, low vinyl polybutadiene, one would obtain a polystyrene with better impact strength, creep and gloss than could be obtained with emulsion polybutadiene or SBR. I am persuaded, however, that the Short article would motivate one of ordinary skill in the art to use Amos’s teachings to make polystyrene with high cis, low vinyl polybutadiene in the expectation that the impact strength and low temperature properties of the resulting product would be superior to compositions made with emulsion polybutadiene or with SBR. Contrary to AHC’s contention, I believe those in the art of making Amos technology polystyrene did look to the properties of the rubber to predict characteristics of the polystyrene product. Accordingly, I believe that one of ordinary skill in the art would see in the resilience and low temperature characteristics of high cis, low vinyl polybutadiene an indication that one could make polystyrene with significantly improved impact strength and that such improvement would be particularly marked in low temperature applications. Richard A. Bishop, then Director of Research at AHC, for example, confirmed in an article published in 1955, that block and graft polymers differ from polymers “made using the same ratios of monomers in the usual process,” because in block and graft polymers “properties of one material can be added onto the backbone of another material without changing the essential nature of the backbone.” Mr. Bishop specifically suggested that a correlation existed between rubber resiliency and its ability to toughen polystyrene: “GR-S synthetic rubber is known to possess excellent resiliency and this material has been added to polystyrene to improve impact strength.” Similarly, Safford taught that block and graft polymer “tend to retain the characteristic properties of the homopolymer of individual monomers.” Indeed, Heinig, as well as Bucknall and Ruffing, confirmed that the art looked to the properties of the rubber as one indicator of the end product properties of impact styrene which might reasonably be expected. While I do not suggest, based upon this evidence, that there was absolute predictability, I do find that those of ordinary skill in the art had a reasonable expectation that a graft copolymer of styrene and polybutadiene, made from polybutadiene having good low temperature properties and excellent resilience, would have the same superi- or properties. I believe this is borne out by the fact that, after dissemination of the information contained in the Short article, those practicing the art who could get their hands on high cis, low vinyl polybutadiene polymerized styrene monomer in the presence of that material within a very short time after they obtained it. As previously noted, Shell prepared impact polystyrene using high cis, low vinyl polybutadiene in late 1957, after receiving a small sample in October. Westphal and Heinig tried high cis, low vinyl polybutadiene immediately upon receiving a sample in April of 1958. Ruffing, at Dow, was unable to secure a sample of stereospecific butadiene until late 1958 and used that sample to make impact polystyrene on January 5, 1959. Indeed, within three years of Shell’s initial work, not only these firms but Cosden, Firestone, Distrene, Monsanto, J.T. Baker Company, and the Richardson Company had all made impact polystyrene reinforced with stereo-specific polybutadiene. While it is true, as AHC contends, that the existence of high cis, low vinyl polybutadiene was publicly announced as early as 1956, I do not find this fact probative of non-obviousness since it was not readily available to artisans working in the polystyrene art until considerably later. In reaching the conclusion that Amos and Short would motivate an artisan of ordinary skill to practice the invention of the patents in suit, I have not overlooked AHC’s argument that there are counter-teachings in the prior art. While it had once been conventional wisdom that one needed a styrene and butadiene copolymer in order to make the modifer compatible with the styrene monomer, by 1958, it was known that such compatibility was not required when making a chemical graft of a rubber toughened plastic, rather than a mechanical blend. Likewise, I do not read the Stoops and Safford patents to teach that high vinyl polybutadiene or low cis polybutadiene are preferable to other types of polybutadienes. Stoops does not refer to the microstructure of polybutadiene. He found that polybutadiene polymerized at 60° C. or below gave better results in his impact polystyrene than did polystyrene polymerized at 90°C., and speculated that the reason why this occurs is the “less highly branched structure” of the 60 °C. polybutadiene, not because of vinyl content. While Stauffer utilized a polybutadiene having a vinyl content of over 30% in making a speciality impact polystyrene with decreased perma plastic flow and “excellent electrical properties”, I do not read his teachings to suggest that high cis, low vinyl polybutadiene would not produce a polybutadiene with good impact