US 4735858

I'll search for authoritative information on this patent number, including any 2026 litigation activity.

Let me check specifically for any litigation or 2026 Federal Circuit activity involving this patent.

US Patent 4,735,858 — Search Summary

Sourcing note / disambiguation

I located the patent on Google Patents and Justia. One important literal-identifier caveat: the string "4735858" also appears as the patent number of an unrelated Japanese patent (J-GLOBAL record: 「フィラメントワインディング自動化システム」/ filament-winding automation system, filed 2007‑09‑27, published 2009‑04‑16). That is a different document with a coincidentally matching numeric string. Everything below refers only to US 4,735,858 (application US06/886,794). I did not treat these as the same record.

Bibliographic data

Abstract (as published)

"A heat-resistant prepreg uses at a substrate a heat-resistant material made of heat-resistant organic fibers, inorganic fibers, etc. and as a matrix a heat-resistant mixture containing at least 10% by weight of a borosiloxane resin composition. This heat-resistant prepreg is obtained by impregnating the substrate at a temperature in the range of 200° to 300° C. to such an extent that at least 20% of the amount of phenyl groups bonded to silicon atoms in the aforementioned borosiloxane resin composition prior to the impregnating and drying steps will remain after the heat treatment."

Independent claims in plain language

The patent has 6 claims total, of which two (claims 1 and 5) are independent.

Claim 1 — the product (a heat-resistant prepreg).
A heat-resistant substrate (e.g., alumina fiber paper) impregnated with a heat-resistant mixture acting as the matrix. Two compositional requirements: (a) the mixture contains at least 10% by weight of a borosiloxane resin composition, with a heat-resistant resin making up the remainder to 100%; and (b) after heat treatment at 200 °C–300 °C, at least 20% of the phenyl groups originally bonded to silicon atoms in the borosiloxane resin must still be present (i.e., the drying must be controlled so as not to destroy the Si–phenyl bonds). No method steps are recited — the claim is defined by the structural/compositional result of that treatment.

Claim 5 — the method (making the prepreg).
A two-step process: (a) impregnating a heat-resistant substrate with a heat-resistant mixture of ≥10 wt% borosiloxane resin composition plus a heat-resistant resin to make up 100 wt%; and (b) drying by heating at ≥200 °C and ≤300 °C, to such an extent that at least 20% of the Si‑bonded phenyl groups present before impregnation/drying survive the heat treatment.

Dependent claims 2–4 specify that the borosiloxane is a polycondensate of (A) R₂SiX₂ (R = methyl or phenyl; X = hydroxy or halogen), (B) boric acid/boric anhydride/boric ester, and (C) dimethyl or phenyl silicone oil (≥1.0 cSt at 25 °C), condensed at 50–800 °C (claim 2); that the heat-resistant resin is silicone resin (claim 3); and that the substrate is alumina fibers (claim 4). Dependent claim 6 narrows claim 5's borosiloxane to a diphenyl silane diol / boric acid / methyl- or phenyl-silicone-oil polycondensate.

Technical underpinning: the specification teaches that the ratio of the IR absorbance at 700 cm⁻¹ after drying (δa) to before drying (δo) must satisfy δa/δo ≥ 0.2, and Table 1 correlates this with tensile shear strength (δa/δo = 0.3–1.0 gave 60–75 kg/cm²; δa/δo = 0.1 gave only 9 kg/cm²).

Prior art cited on the face of the patent

US 4,152,509; US 4,228,270; US 4,361,679; US 4,405,687; US 4,460,639.

Litigation / CAFC 2026 activity

No litigation or Federal Circuit activity involving US 4,735,858 was found. My searches of the Federal Circuit docket space for 2026 returned only unrelated matters (e.g., AeroVironment § 1498 appeal; Contour IP Holding LLC v. GoPro, Inc., Fed. Cir. No. 2026‑2012), none of which reference this patent. A targeted search for infringement/litigation tied to this number returned no results.

This is unsurprising and consistent with the record: the patent is recorded as expired for failure to pay maintenance fees (lapse effective around 2000‑04‑05), and the application was filed before June 8, 1995, so its term would have ended 17 years from grant (April 2005) at the latest. An expired forum-fee-lapsed patent from 1988 being in active 2026 appellate litigation would be anomalous.

Uncertainty statement

• I am highly confident in the bibliographic data, abstract, claim structure, and status above — they come from the full patent text and Google Patents/Justia records.
• The exact expiry mechanics are slightly ambiguous in the source data: Google's "legal events" shows both a 2000 lapse/failure-to-pay entry and a 2018 "patent expired due to nonpayment" entry. I report both literally rather than reconciling them; a USPTO PatentCenter/PAIR check would be needed to state the precise legal expiration date with certainty.
• I could not verify any CAFC 2026 docket for this patent, and I found no affirmative evidence one exists. This is a negative finding from the searches performed, not a certified "no cases ever" conclusion — a direct PACER/CourtListener docket query on the patent number would be the authoritative confirmation.

I'll search for litigation involving US patent 4735858 across patent litigation databases.

Initial results show no litigation hits. Let me search dedicated litigation databases and other sources.

Litigation Search Results for US Patent 4,735,858

Finding: No litigation involving US Patent 4,735,858 was located.

I searched the sources you specified (Unified Patents litigation portal, plus general web searches aimed at PACER/CAFC litigation records and patent-specific databases) for the exact number 4,735,858 / 4735858. No case—district court, CAFC, ITC, PTAB, or other forum—asserting or otherwise involving this patent was found.

What the searches did and did not show

I note that some search hits referenced similarly-numbered patents (e.g., US 10,621,228; US 8,767,824) and other parties (MemoryWeb, MCOM IP, etc.). These are different patents and I have excluded them, as you instructed.

Context on why no litigation is likely

• Owner/assignee: Original assignee Showa Electric Wire & Cable Co., Ltd.; current listed assignee SWCC Corp (per Google Patents). This is an industrial materials company, not a patent-assertion entity.
• Status: The patent is recorded as "Expired – Fee Related." Legal events show a maintenance-fee reminder (1999), lapse for failure to pay maintenance fees (2000), and confirmation of expiration due to nonpayment under 37 CFR 1.362. The patent thus lapsed around April 2000 and would have reached its full 20-year term in 2006 in any event.
• Subject matter: A heat-resistant prepreg/borosiloxane resin composition (1985 priority, JP 60-159417 and JP 61-162724). This is a niche materials patent that appears never to have been asserted.

Limitations / caveats

• I could not directly query PACER or the CAFC docket system (they are not fully web-crawlable and typically require authenticated/paid access), so this conclusion rests on the accessible litigation aggregators (Unified Patents portal, CourtListener/recap results, general web search) rather than a guaranteed complete PACER docket sweep.
• Given the patent expired roughly 26 years ago and was never held by a known litigating entity, the probability of undiscovered litigation is low, but I cannot state with absolute certainty that no case ever existed.

Bottom line: Based on the sources searched, there is no known litigation involving US Patent 4,735,858. If you need a definitive PACER/CAFC records check, that would require a direct docket query with appropriate access credentials, which I do not have here.

PTAB / AIA Trial Analysis — U.S. Patent No. 4,735,858

Patent: Heat-resistant prepreg and method for production thereof
Patent Owner (current assignee per Google Patents / ODP): SWCC Corp (originally Showa Electric Wire & Cable Co., Ltd.)
Grant: 1988-04-05 · App. No.: 06/886,794 · Filed: 1986-07-18 · Priority: 1985-07-19 (JP 60-159417) / 1986-07-10 (JP 61-162724)
Claims: 6 (2 independent — claim 1 composition-of-matter prepreg; claim 5 method of production)
Source of record: https://patents.google.com/patent/[US4735858](/patent/US4735858)/en

Proceedings overview

Total AIA trial proceedings on file: 0. The structured "PTAB proceedings on file" block (USPTO Open Data Portal ingest) returns no IPR, PGR, or CBM for U.S. 4,735,858, and my web searches surfaced no petition, institution decision, Final Written Decision, or Federal Circuit appeal naming the patent — so there are zero claims invalidated, zero claims sustained, zero settlements, and zero institution denials to report. The bottom-line defensive posture is therefore not "hardened patent" or "claims canceled" — it is a dead-patent posture: the patent lapsed for nonpayment of maintenance fees effective 2000-04-05 (USPTO legal events: LAPS 2000-04-02; FP "Lapsed due to failure to pay maintenance fee," effective 2000-04-05; STCH 2018-01-30 "PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362"). A defendant receiving a demand letter citing this patent does not need an IPR — it needs a copy of the Patent Center fee record.

Proceedings

None. There is no proceeding to list in the required per-proceeding format, and I will not construct one.

Rather than populate the template with fabricated numbers, here is the verified negative result plus the reason the negative is structural rather than accidental:

Why it is structural. AIA trials began 2012-09-16. U.S. 4,735,858 had already been expired for over twelve years by that date. An IPR petition is also subject to the 35 U.S.C. § 315(b) one-year bar running from service of an infringement complaint; with the patent lapsed since 2000, no conforming petitioner/timeline exists. Practically speaking, this patent was never IPR-eligible during any period in which it was enforceable.

Legibility caveat for the record. I could not open PTAB E2E / PTAB Decisions directly in this session; the authoritative proceeding list I relied on is the structured ODP block supplied in the prompt ("The USPTO ODP API returns no AIA trial proceedings for this patent as of the most recent ingest"). Per the operating instructions, I searched to look for older or not-yet-ingested filings and found none. If a proceeding exists that neither source indexes, it would be an ODP ingest gap — a Patent Center / PTAB E2E docket pull is the clean way to close that.

Strategic summary

Claim-by-claim status of 4,735,858. Claims 1–6 are UNTESTED — not canceled, not sustained, because no tribunal ever reached them. Claim 1 (at least 10 wt% borosiloxane resin composition + heat-resistant resin to 100 wt%, with ≥20% of Si-bonded phenyl groups surviving heat treatment at 200–300 °C), claims 2–4 (borosiloxane made from R₂SiX₂ + boric acid/anhydride/ester + silicone oil ≥1.0 cSt at 25 °C; silicone-resin matrix; alumina-fiber substrate), claim 5 (the method), and claim 6 (diphenyl silane diol + boric acid + methyl/phenyl silicone oil polycondensed at 50–800 °C) all stand or fall together on the Expired - Fee Related status of the whole patent. There is no narrowing to exploit and no surviving claim to design around — the entire right lapsed.

Estoppel landscape. Because no IPR reached an FWD, no § 315(e)(2) estoppel exists against anyone. Every prior-art ground is nominally still open in district court — but that is a technicality with no practical value, since an expired patent cannot be infringed. The lapsed status (2000-04-05) is the dominant fact, not estoppel. Separately, if the patent were ever revived via a 37 C.F.R. § 1.378 petition, intervening rights under 35 U.S.C. § 41(c)(2) would protect substantial pre-revival investments and continued manufacture/use/sale on equitable terms; the statute's text tracks 35 U.S.C. § 252 and the Roche/Bolar line of reasoning, and injunctions are unavailable once a patent's rights end (Kearns v. Chrysler Corp., 32 F.3d 1541 (Fed. Cir. 1994) — "when the rights secured by a patent are no longer protectable by virtue of expiration or unenforceability, entitlement to injunctive relief becomes moot"). Revival after 26 years is, practically, foreclosed; the § 1.378 window for "unintentional" delay ran out long ago, and "unavoidable" delay would require a showing this record cannot support.

Pattern signals. All nil, because the dataset is empty:

• Repeat petitioners: none — no petitioner at all.
• Patent Owner appeal aggressiveness: no CAFC activity; applicant/owner never appeared before the PTAB at trial stage on this patent. (The same assignee, Showa Electric Wire & Cable, appears in the cited prior art of this very patent via US 4,405,687, and JP family members JPH0645709B2 and JPH0788431B2 issued 1994-06-15 and 1995-11-29 respectively — but those are prosecution/foreign-family events, not PTAB history.)
• Defensive aggregator (Unified Patents, RPX, etc.): no involvement. Unified does appear in other Fintiv-era filings in my search results, but not on this patent.
• Foreign counterparts: GB2180857B (granted 1990-02-14) and CA1291378C (granted 1991-10-29). Both are likewise long expired and are not U.S. enforcement vehicles.

The real read: a 1988 prepreg patent that has been dead since 2000 does not attract IPRs — assertion value is zero. Well-asserted patents eventually attract PTAB filings; the corollary is that a patent with 26 years of PTAB silence and a lapse-for-nonpayment entry is a paper tiger. Any 2026 demand letter citing 4,735,858 is either an error (wrong patent number), an attempt to assert an expired right, or a portfolio-substitution play where the real asserted patent is a continuation or a later-issued relative.

Recommended next steps

1. If you are a defendant / recipient of a demand letter citing 4,735,858: do not file an IPR. An IPR on an expired patent achieves nothing and the expired-patent defense is dispositive. Pull the fee record instead:
   • USPTO Patent Center (file wrapper, fee/status tab): https://patentcenter.uspto.gov/
   • Google Patents legal-status line, verbatim: "Expired - Fee Related" — https://patents.google.com/patent/US4735858/en
   • The dispositive entries are LAPS 2000-04-02, FP effective 2000-04-05, and the 2018-01-30 STCH record confirming expiration under 37 CFR 1.362.
   • Respond in writing that the patent lapsed for nonpayment of maintenance fees effective 2000-04-05, that no enforceable rights exist for post-2000 conduct, and that injunctive relief is unavailable per Kearns v. Chrysler Corp., 32 F.3d 1541 (Fed. Cir. 1994).
2. Confirm there is no live continuation/reissue in the family. The ODP family listing shows only US 06/886,794 with US publication US4735858A; there is no listed U.S. continuation. If the asserting party is monetizing the technology rather than this serial number, ask for the actual asserted patents and check whether any of them is a reissue or continuation of the 1985-07-19 / 1986-07-10 priority chain. (CA1291378C and GB2180857B are foreign counterparts, both expired.)
3. Close the residual unknown on pre-AIA proceedings. The ODP block covers AIA trials only. A proper docket pull should check:
   • PTAB E2E / PTAB Decisions: https://ptacts.uspto.gov/ptabweb/
   • Patent Center "Documents" tab for any ex parte reexamination request, reissue, or disclaimer.
     This matters because an ex parte reexamination is a third-party event that would not show up as an AIA trial and could, in theory, have amended the claims during the patent's enforceable life.
4. Watch for a § 1.378 revival petition as a low-probability risk item. If the patent were revived, the entire analysis shifts to 35 U.S.C. § 41(c)(2) intervening rights — you would want documentation of pre-revival manufacturing, sales, and substantial preparation, since that evidence supports absolute intervening rights and an equitable carve-out even for continued activity. Given the 2000 lapse date, confirm revival has not occurred and note it in any responsive pleading.
5. Do not rely on the "anticipated expiration 2006-07-18" figure. That 20-year date in the ODP metadata is a computational artifact; the patent actually terminated in 2000 for fee nonpayment. Cite the fee record, never the projected term.

Bottom line

No PTAB proceedings on file — and none is coming. U.S. 4,735,858 was never challenged at the PTAB because it was never eligible there during its enforceable life, and it has been expired for fee nonpayment since 2000-04-05. For a defendant today, that is a stronger position than any IPR win: you are not defending against a claim that was canceled — you are defending against a patent that stopped existing twenty-six years ago.

I'll verify the assignment record against USPTO sources and check for any post-issuance transfers before building the chain.

Let me check the USPTO Assignment Center record directly and the corporate history of the assignee.

The register search didn't surface the Assignment Center record directly. Let me try the assignment API endpoint and the reel/frame number.

I was able to confirm the corporate-history facts and the single recorded assignment, but the Assignment Center's own record view (which is what exposes reel/frame, correspondent, and conveyance text) could not be retrieved through the search interface within the tool budget. Here is the reconstruction, with the gaps marked honestly.

Assignment Record Reconstruction — US 4,735,858

Patent: US 4,735,858 (US4735858A) — "Heat-resistant prepreg and method for production thereof"
Application: US 06/886,794 · Filed 1986-07-18 · Granted 1988-04-05
Verification entry point: USPTO Assignment Center (search by patent number 4735858); mirrored index at assignment.uspto.gov

Evidence-base caveat, stated up front. The Google Patents legal-events mirror for this patent exposes exactly one assignment entry (the 1986 inventor-to-company assignment, with its reel/frame). The assignment-search endpoints did not return a case-level record I could read directly, so the correspondent-of-record field for that assignment is not available to me and I have not guessed at it. Everything below is sourced to the full patent text, the Google Patents legal-events register, and verified corporate-history sources for the assignee — not to a live Assignment Center screenshot.

Inventors

Both inventors assigned their rights to Showa Electric Wire & Cable Co., Ltd. by an assignment executed 1986-07-11 — seven days before the 1986-07-18 filing date. That pre-filing, joint, employee-style conveyance is the ordinary pattern for a Japanese corporate R&D filing and is consistent with both men being in-house Showa engineers. There is no hint of contested ownership, inventor-to-inventor assignment, or interest-splitting.

Departure pattern: Not determinable. I found no employment-tenure data for either inventor, so I cannot assess the "all inventors departed within 12 months of filing" fire-sale precursor. I explicitly decline to infer it from the assignment timing — a routine employee assignment is not evidence of departure, in either direction. The earlier summary's disambiguation note also applies here: the J-GLOBAL record for a Japanese patent numbered 4735858 (「フィラメントワインディング自動化システム」, app. 2007-250917, published 2009-04-16) surfaced again in this round of searching and is a different document; it contributes no inventor data for US 4,735,858.

Original assignee

Showa Electric Wire & Cable Co., Ltd. (昭和電線電纜株式会社), 2-1-1 Odasakae, Kawasaki-ku, Kawasaki, Kanagawa, Japan — the address fragment "2-1-1, ODAS…" appears verbatim in the recorded assignment entry.

• Primary line of business: design, manufacture, sale, and installation of electric wires and cables — power cable, communication cable, magnet wire, oxygen-free copper, seismic-isolation devices, plus wire harnesses and precision devices. The company's own Integrated Report dates its founding to 1936 as a spin-off from Tokyo Electric Company (today's Toshiba) and its Tokyo Stock Exchange listing to 1949. (SWCC Group Report — company history)
• Product embodying the claims? Unclear / no direct evidence found. The patent's subject matter (a borosiloxane-resin-matrix prepreg for alumina-fiber and similar substrates) sits adjacent to Showa's known materials competency — Showa is itself the assignee of cited prior art US 4,405,687 ("Polyborosiloxane composition for production of electrically insulating layer and insulated electric wire using the composition"), confirming it genuinely worked in polyborosiloxane materials. But I found no evidence of a commercial prepreg product sold under the claims of 4,735,858. I am flagging this as a genuine gap rather than implying the claims were never practiced.
• Current status: Operating. Corporate lineage, confirmed across three sources:
  • 2006-04 — converted to a pure holding company and renamed SWCC Showa Holdings Co., Ltd. (昭和電線ホールディングス株式会社); cable and device operations split into subsidiaries.
  • 2011 — business/capital alliance with China's Futong Group, whose Hong Kong arm became largest shareholder (~19.1% per later disclosures) — a period of financial distress, not insolvency: net loss of ¥8.5bn in FY2009 and a second consecutive loss the following year, with the equity ratio collapsing. (SWCC company history)
  • 2017 — operating subsidiaries consolidated.
  • 2023-04-01 — absorbed SWCC Showa Cable Systems and SWCC Showa Unimac, unwound the holding structure, and renamed itself SWCC Corporation. This is why Google Patents lists the current assignee as "SWCC Corp."
  • No bankruptcy. Despite the 2009–2013 distress, I found no Chapter 7/11 equivalent, no civil rehabilitation, and no patent auction involving this entity.

Cross-reference flag for the reviewers: the corporate-succession facts above are corroborated by recorded merger assignments on other SWCC patents — e.g. US 9,842,681 carries SWCC SHOWA CABLE SYSTEMS ← SWCC SHOWA DEVICE TECHNOLOGY (merger/change of name, effective 2017-04-01, reel 043889/0044) and SWCC CORPORATION ← SWCC SHOWA CABLE SYSTEMS (merger, effective 2023-04-23, reel 066740/0471). Those reel numbers belong to US 9,842,681, not to US 4,735,858 — do not carry them across. Their relevance is evidentiary only: they prove the same corporate chain that would apply here.

Assignment timeline

One (1) recorded assignment exists.

• 1986-07-11 (executed) / recorded 1986-07-18 — Reel 004579 / Frame 0877
  • Conveyance: Assignment
  • Assignor: Etsuo Hosokawa; Hiroshi Hashimoto (joint inventors)
  • Assignee: Showa Electric Wire & Cable Co., Ltd., 2-1-1 Odasakae, Kawasaki-ku, Kawasaki, Kanagawa, Japan
  • Correspondent: Not exposed in the indexed record. The legal-events entry carries only owner name, free-format text ("ASSIGNMENT OF ASSIGNORS INTEREST"), the assignor names, and the reel/frame. The recording correspondent — the attorney or agent who filed it with the USPTO — must be read off the assignment document image at reel 004579, frame 0877. I did not retrieve that image and will not name a correspondent I have not seen. This is the single most important unresolved field in this report.
  • Context: Pre-filing employee invention assignment (internal capture of inventor rights by the corporate employer). Ordinary.
  • Recurrence flag: Not assessable — only one link in the chain, and its correspondent is unknown, so the "repeat correspondent" tell cannot even be tested here.

No post-issuance assignment is recorded. The full Google Patents legal-events log for this patent reads, in order:

Everything after 1995 is fee administration. There is no merger, change-of-name, security-interest, license, release, or correction record on this patent — which is itself the finding: the 2006 holding-company renaming and the 2023 SWCC renaming were not separately recorded against this patent, so Google Patents' "Current Assignee: SWCC Corp" is a lineage inference, not a reel/frame-documented transfer. The legal owner of record on the last day of the patent's life was still nominally Showa Electric Wire & Cable Co., Ltd.

Timeline diagram

timeline
    title Ownership of US 4735858
    1985 : JP priority applications filed
    1986 : Inventors assign to Showa Electric
    1988 : US patent granted
    2000 : Patent lapses for unpaid fees
    2006 : Assignee becomes SWCC Showa Holdings
    2023 : Assignee renamed SWCC Corporation

NPE / troll-pattern signals

Verdict

Insufficient data (only the original assignment is on record)

Justification: the entire documented chain consists of a single 1986 pre-filing employee assignment of the inventors' rights to Showa Electric Wire & Cable Co., Ltd. at reel 004579/frame 0877 — a purely internal capture with no third-party, no licensing vehicle, and no subsequent transfer of any kind. Every hallmark NPE prerequisite is factually absent: the patent lapsed for failure to pay maintenance fees effective 2000-04-05 (with a 2018 STCH confirmation entry), roughly 26 years before today, and its original owner is a Tokyo-listed wire-and-cable manufacturer (now SWCC Corporation) that never sold the asset. The one thread I could not pull — the correspondent of record on reel 004579/0877 — cannot change this verdict; a 1986 in-house assignment to an operating Japanese industrial has no plausible NPE significance regardless of which attorney filed it. The honest characterization is therefore "operating-company-owned for life, expired, no assertion chain," which the taxonomy codes as insufficient data rather than a positive NPE or defensive-aggregator finding.

Two contradictions to flag against the earlier sections:

1. The prior summary's "Current Assignee (listed): SWCC Corp" is not supported by any recorded assignment on this patent. It reflects Google Patents' corporate-lineage inference, not a reel/frame. The assignee of record from 1986 until lapse was Showa Electric Wire & Cable Co., Ltd.
2. The prior summary's "Expired – Fee Related" and its note that the 2000 and 2018 entries are "slightly ambiguous" — I agree with leaving both reported literally. The two entries are consistent rather than contradictory if read as (a) the 2000 lapse for failure to pay the 8-year fee and (b) the 2018 administrative closure of the record; the authoritative reconciliation requires a USPTO PatentCenter/PAIR lookup, which I could not perform here.

Verification: search patent number 4735858 at the USPTO Assignment Center and pull the document image for reel 004579, frame 0877 to recover the correspondent field that this reconstruction could not supply.

I'll search for the prior-art references cited on the face of US 4,735,858 to build accurate citations and anticipation analysis.

Prior Art Analysis — US 4,735,858 (application US 06/886,794)

0. Scoping and sourcing note

A live USPTO PatentCenter/PAIR query could not be completed in this session, so the citation set below is taken from the authoritative full text of US 4,735,858 (Google Patents mirror, which reproduces the printed "Patent Citations (5)" list from the face of the document). The patent's own text labels this list: "Patent Citations (5)" — so the examiner-cited patent prior art is exactly five references. I also exclude the 8 "Cited By" documents and the 14 "Cited By (14)" entries: those are later publications and are not prior art to this patent.

One literal-identifier caveat carried over from the prior sections: the numeric string 4735858 also appears in unrelated records; everything here refers only to US 4,735,858, priority 1985-07-19 (JP 60-159417) and 1986-07-10 (JP 61-162724), filed 1986-07-18, granted 1988-04-05, assignee Showa Electric Wire & Cable Co., Ltd.

Governing § 102 framework. All five cited references were published more than one year before the 1985-07-19 priority date, so each is available under 35 U.S.C. § 102(b) as a statutory bar (and under § 102(a) for anything shown before the invention date). Note also that US 4,735,858 is a pre-AIA patent (filed 1986), so pre-AIA § 102 governs throughout.

Important framing for anticipation. Anticipation under § 102 requires a single reference to disclose every element of a claim, arranged as in the claim. The independent claims here each contain a limitation that no cited reference discloses: the phenyl-retention requirement (≥ 20% of Si-bonded phenyl groups surviving) and, for claim 1, the "prepreg" structural character (a heat-resistant substrate impregnated with the matrix). No single cited reference anticipates claims 1, 4, or 5 as a whole. The citations are strongest against the dependent composition claims (2, 3, 6), which recite the borosiloxane polymer chemistry and the heat-resistant-resin admixture in isolation.

1. The five examiner-cited references

Reference 1 — US 4,152,509

Full citation: US 4,152,509 A, "Borosiloxane polymers and a method for producing the same," The Foundation: The Research Institute For Special Inorganic Materials; appl. US 05/835,373; filed 1976-09-30; published 1979-05-01.
URL: https://patents.google.com/patent/[US4152509A](/patent/US4152509A)/en

Brief description: Discloses borosiloxane polymers and a method of making them by reacting a boron compound (e.g., boric acid) with organosilicon compounds and a silicone oil to form a boron–silicon–oxygen (borosiloxane) backbone. This is foundational borosiloxane chemistry from the same research lineage (Seishi Yajima's group) that produced several of the other citations here. It is a polymer/composition reference — it is not directed to impregnated prepregs, substrates, or drying schedules.

Potential § 102 anticipation:

• Claim 2 — Potentially anticipatory as to the borosiloxane composition per se: it teaches a polycondensate of a boron compound with silane/organosilicon components and a silicone oil, which is the genus recited in claim 2. The mapping is not exact unless the reference also uses the R₂SiX₂ silane species and the ≥1.0 cSt silicone oil, so this is a facial rather than a clean anticipation — the examiner appears to have cited it as background/method art for the borosiloxane.
• Claim 6 — Same reasoning (broad borosiloxane polycondensate disclosure).
• Claims 1, 3, 4, 5 — Not anticipated. No heat-resistant substrate, no matrix + heat-resistant-resin admixture, no 200–300 °C drying step, and no phenyl-retention criterion.

Reference 2 — US 4,228,270

Full citation: US 4,228,270 A, "Polyborodiphenylsiloxanes," Asahi Kasei Kogyo Kabushiki Kaisha; appl. US 05/969,006; filed 1977-12-14; published 1980-10-14 (status: Expired – Lifetime).
URL: https://patents.google.com/patent/US4228270

Brief description: Discloses polyborodiphenylsiloxanes and their preparation by polycondensation of a borodiphenylsiloxanol / boric acid system. Critically, these polymers carry phenyl groups on silicon (diphenylsiloxy units) — exactly the Si–phenyl bonds whose retention the patent-at-issue makes claim-critical. It is a polymer/composition reference, not a prepreg or impregnation reference.

Potential § 102 anticipation:

• Claim 2 — Potentially anticipatory as to the phenyl-bearing borosiloxane genus (a polyborodiphenylsiloxane is a borosiloxane polycondensate containing Si–phenyl groups).
• Claim 6 — Relevant, because claim 6 specifies diphenyl silane diol + boric acid; a "polyborodiphenylsiloxane" is squarely within that family (subject to confirming the same silicone-oil component).
• Claims 1, 3, 4, 5 — Not anticipated (no substrate, no matrix blend, no drying/retention limitation).

Reference 3 — US 4,361,679

Full citation: US 4,361,679 A, "Process for producing heat-resistant and moisture-resistant polyborometallosiloxanes," NTN Toyo Bearing Co., Ltd.; appl. US 06/278,929; filed 1981-06-30; published 1982-11-30.
URL: https://patents.google.com/patent/US4361679

Brief description: Discloses a process for making heat-resistant and moisture-resistant polyborometallosiloxanes by adding a metal compound (Ti, Zr, V, P, Al, Fe, Cr, Co, Ni, Ge, Sn, As, Mg, Pb, Sb, etc.) to an organoborosiloxane and heating (≤ ~550 °C) to bond the metal through oxygen to Si/B. The abstract confirms the organoborosiloxane starting material and the heat treatment. It is directed to moisture resistance of the borosiloxane polymer, not to prepregs.

Potential § 102 anticipation:

• Claim 2 / Claim 6 — Only weakly relevant. It presupposes an organoborosiloxane (the same genus claims 2/6 recite) but its point of novelty is the metal-modified product. Because claim 2 does not exclude metals, a metal-containing polyborosiloxane could still arguably read on claim 2's genus — but the reference does not expressly show the (A)+(B)+(C) reactant set of claim 2 or the diphenyl-silane-diol/boric-acid/methyl-silicone-oil set of claim 6, so this is background rather than clean anticipation.
• Claims 1, 3, 4, 5 — Not anticipated.
• Its real significance is confirmatory: it establishes that borosiloxane polymers were known to have a moisture/hydrolysis weakness, which is the problem the patent-at-issue's phenyl-retention teaching addresses.

Reference 4 — US 4,405,687 (the single most relevant citation)

Full citation: US 4,405,687 A, "Polyborosiloxane composition for production of electrically insulating layer and insulated electric wire using the composition," Showa Electric Wire & Cable Co., Ltd.; appl. US 06/367,025; filed 1981-04-13; published 1983-09-20 (inventors incl. Morita et al.).
URL: https://patents.google.com/patent/US4405687

Brief description: This is the closest § 102 art, and it comes from the same assignee (Showa Electric Wire & Cable) as the patent-at-issue. It discloses a thermally resistant resinous composition comprising:

• (A) a polyborosiloxane obtained by polycondensation at 50°–800 °C of (1) a boron compound (boric acids, boric anhydride, metallic salts of boric acid, halogenated borons, boric esters), (2) a silane compound of formula SiX₄, SiRX₃, or SiRR′X₂ (R, R′ = methyl or phenyl; X = hydroxyl or halogen), and (3) a silicone oil selected from dimethyl silicone oil and phenyl methyl silicone oil having a viscosity of at least 1.0 cSt at 25 °C (preferably ≥10 cSt);
• (B) at least one thermally resistant synthetic resin — expressly including silicone resins and nitrogen-heterocycle resins (polyimide, polyamideimide, polyimidazopyrrolone);
• (C) an inorganic filler; and (D) a common solvent for (A) and (B).

This reactant list is, element-for-element, the same A/B/C borosiloxane definition used in claim 2 of the patent-at-issue (and the silicon-oil viscosity threshold of claim 2/6).

Potential § 102 anticipation:

• Claim 2 — Strongly anticipatory candidate. Every element of claim 2's borosiloxane definition (R₂SiX₂ with R = methyl/phenyl and X = hydroxy/halogen; boron compound selected from boric acid/boric anhydride/boric ester; dimethyl or phenyl silicone oil ≥1.0 cSt at 25 °C; polycondensation at 50–800 °C) appears to be disclosed in US 4,405,687 in nearly verbatim terms. This is the reference most likely to have driven the examiner's rejection of claim 2.
• Claim 6 — Anticipatory candidate to the extent the reference's SiRR′X₂ with R = R′ = phenyl and X = OH reads on diphenyl silane diol and its silicone oil is a methyl/phenyl silicone oil; the 50–800 °C polycondensation range is expressly disclosed.
• Claim 3 (heat-resistant resin = silicone resin) — Anticipatory candidate as to the silicone-resin component, since (B) expressly includes silicone resins as the thermally resistant resin blended with the polyborosiloxane.
• Claim 1 — NOT fully anticipated. The reference is an insulating coating/wire composition, not a prepreg; it discloses no heat-resistant substrate impregnation and, decisively, no ≥20 % Si-phenyl retention after a 200–300 °C treatment. Claim 1 as a whole therefore survives on its own.
• Claims 4 and 5 — Not anticipated (no alumina-fiber substrate; no prepreg-making drying step or retention criterion).

Reference 5 — US 4,460,639

Full citation: US 4,460,639 A, "Fiber reinforced glass matrix composites," Dow Corning Corporation (inventors Frank K. Chi, Gary L. Stark); appl. US 06/482,685; filed 1983-04-06; published 1984-07-17.
URL: https://patents.google.com/patent/US4460639

Brief description: Discloses a method of making fiber-reinforced glass composites by (A) impregnating high-modulus fibers with a resin sol (a sol of an organosilsesquioxane such as [C₆H₅SiO₃/₂][RSiO₃/₂], optionally mixed with a colloidal metal oxide or metal alkoxide), (B) forming a prepreg by drying, (C) heating the prepreg, (D) pressing at a temperature not greater than about 300 °C, (E) curing at not greater than about 300 °C, and (F) firing to ≥1000 °C to convert to a glass matrix. Fibers disclosed include carbon, silicon carbide ("Nicalon"), and an alumina-boria-silica fiber ("Nextel 312"); the reference expressly notes the low-temperature (≤300 °C) laminating/curing as a distinction over hot-pressing. Its organosilsesquioxane sol carries phenyl groups (C₆H₅SiO₃/₂).

Potential § 102 anticipation:

• Claim 5 — Closest structural analogue for the method, and the reference most relevant to the process concept: it discloses impregnating a heat-resistant fiber substrate with a resin, forming a prepreg by drying, and heating at ≤300 °C (steps (b)–(d)). However, it does not anticipate claim 5: the impregnating resin is an organosilsesquioxane sol / metal-oxide / metal-alkoxide sol system, not a borosiloxane resin composition + heat-resistant resin blend at ≥10 wt % borosiloxane, and it discloses no 200–300 °C drying to a defined phenyl-retention level. Claims 5's two compositional and numerical limits are absent.
• Claim 4 (substrate = alumina fibers) — Potentially anticipatory insofar as "Nextel 312" is an alumina-boria-silica fiber; whether that reads on "alumina fibers" literally is a claim-construction question (the fiber is not pure alumina). Flag as a possible but not clean § 102 hit.
• Claim 1 — Not anticipated (organosilsesquioxane matrix, no borosiloxane-inclusive mixture at ≥10 wt %, no phenyl-retention limitation).
• Claims 2, 3, 6 — Not anticipated (no borosiloxane polycondensate chemistry; the sol is a silsesquioxane, not a B-containing borosiloxane).

2. Consolidated anticipation matrix

3. Bottom line

• Most relevant single reference: US 4,405,687 (Showa Electric Wire & Cable — the patent-at-issue's own assignee). It maps element-for-element onto the borosiloxane composition defined in dependent claim 2 and onto the diphenyl/boric-acid/methyl-silicone-oil polycondensate of claim 6, and it supplies the silicone-resin component of claim 3. It is the citation that most plausibly drove rejection of those dependent claims.
• Second most relevant: US 4,460,639 (Dow Corning). It is the only cited reference that is itself about impregnating a heat-resistant fiber substrate to form a prepreg and heating at ≤300 °C, and therefore the most relevant art against the process concept of claim 5 and the substrate of claim 4 — though it fails § 102 on claim 5 because it uses an organosilsesquioxane sol rather than a ≥10 wt % borosiloxane/heat-resistant-resin mixture and has no phenyl-retention requirement.
• US 4,152,509, US 4,228,270, US 4,361,679 are borosiloxane-chemistry background (polymer species and moisture resistance). They are relevant to the genus recited in claims 2/6 but do not disclose the prepreg, the matrix blend, or the drying/retention limitation.
• Critically, none of the five cited references anticipates independent claims 1 or 5 as a whole, because none discloses the numerically defined phenyl-retention limitation (δa/δo ≥ 0.2; ≥20 % of Si-bonded phenyl groups surviving) nor the full combination of a borosiloxane-inclusive matrix at ≥10 wt % on a heat-resistant substrate dried at 200–300 °C. That retention criterion — grounded in the patent's IR absorbance-at-700 cm⁻¹ teaching and Table 1 — is the point of novelty the citations do not reach.

Caveats: (i) I could not run an authenticated USPTO PatentCenter/PAIR query, so the citation set is taken from the printed "Patent Citations (5)" list in the patent's own full text; (ii) the anticipation characterizations above are based on the cited references' disclosed subject matter as retrieved, and a definitive element-by-element § 102 determination would require reading the full specifications of each reference (not just abstracts/claims) — in particular US 4,405,687's examples and US 4,460,639's claim 1.

I'll ground the obviousness analysis in the actual disclosures of the five references cited on the face of US 4,735,858. Let me pull what I can on each.

Let me get the claim language of the two most structurally important references.

Obviousness Analysis — US 4,735,858 under 35 U.S.C. § 103

Reference set used (the "Prior Art" / Patent Citations section of the patent page):

Threshold point on prior‑art status. Each of these issued more than one year before the 1986‑07‑18 U.S. filing (and before the one‑year critical date measured from that filing, 1985‑07‑18). All are therefore § 102(b) statutory‑bar art; the JP priority claims (60‑159417, 61‑162724) do not remove a § 102(b) bar, which runs from the U.S. filing date. The content of all five was before the examiner (they appear on the face), but mere citation does not mean a § 103 combination was ever articulated or overcome — a fresh combination of these references is entirely available as an invalidity theory.

1. Legal framework

Under Graham v. John Deere and KSR Int'l v. Teleflex, the inquiry is: (1) scope and content of the prior art; (2) differences between the prior art and the claims; (3) PHOSITA's level of skill; (4) secondary considerations. Under KSR, a combination is obvious where the prior art elements perform their known functions with predictable results, where there is a "finite number of identified, predictable solutions," or where a technique known to improve one device is applied to a similar device in the same way.

PHOSITA definition (I would propose): a bachelor's degree in polymer/materials science or chemistry plus 2–4 years' experience formulating silicone/borosiloxane resins, impregnating fiber substrates and heat‑treating prepregs — i.e., someone who reads both the silicone‑resin coating art (e.g., '687) and the fiber‑composite/prepreg art (e.g., '639).

One literal‑reading flag (carried forward and worth restating): the specification's drying passage reads "not less than 200° C. and more than 300° C." — an internally contradictory range. Claims 1 and 5, the abstract, and the Figure's region II all say 200–300 °C inclusive. I treat the claims' "not more than 300 °C" as controlling and the specification sentence as a typographical error; it does not affect the analysis below, but it does confirm that the upper bound (300 °C) is the operative limit.

2. What each reference teaches, mapped to the claim elements

Independent claim 1 (product)

Independent claim 5 (method)

Steps (a) impregnation with ≥10 wt% borosiloxane + heat‑resistant resin, and (b) drying at 200–300 °C with ≥20% phenyl retention map as follows:

• Step (a): '639 step (A)+(B); '687's coating/composition disclosure.
• Step (b): '639's "pressing … at a temperature not greater than about 300° C." and "curing … at a temperature not greater than about 300° C."; and, for the lower bound, the solvent‑selection teaching — '687 uses n‑methyl‑2‑pyrrolidone and xylene as the common solvent and bakes at 400–450 °C; NMP (b.p. ≈ 202 °C) and xylene (b.p. ≈ 138–144 °C) dictate that practical solvent evolution requires heating to at least about 200 °C, which is exactly the rationale '858 itself gives for its 200 °C floor.

Dependent claims

3. The obviousness combinations

Ground 1 (strongest): US 4,405,687 + US 4,460,639

Both references are in the same field of endeavor (heat‑resistant resin‑impregnated/bonded fiber structures), and both come from the same corporate/technical lineage — '687 is the patentee's own prior work (Showa Electric Wire & Cable, the assignee of '858). The combination supplies every element of claims 1 and 5:

• '687 supplies the matrix: a polyborosiloxane composition blended with a heat‑resistant resin (silicone resin, or polyimide) in a common solvent, at blend ratios (50:50) that sit squarely inside the claimed "≥10% by weight borosiloxane" window, applied to a substrate and baked to develop heat resistance.
• '639 supplies the article and the temperature parameter: impregnate heat‑resistant (incl. alumina‑based) fibers with a phenyl‑bearing organosilicon resin, dry to a prepreg, press/cure at ≤300 °C and only thereafter fire to ceramic. '639's express purpose for holding the pre‑fire steps to ≤300 °C — avoiding "excessive curing" so the prepreg remains fusible/adherable — is the same functional requirement that '858's 200–300 °C window serves.

Motivation to combine: '858's problem is stated in its own background — epoxy/unsaturated‑polyester prepregs are limited to ~120 °C and "cannot be joined without an adhesive agent." '687 was expressly developed for thermal resistance of an applied resin layer over a conductor, and '639 was expressly developed to obtain a laminable prepreg that avoids hot‑pressing. A POSITA seeking a heat‑resistant, self‑adherent prepreg would (i) select the known thermally superior borosiloxane resin of '687, and (ii) adopt '639's impregnate‑dry‑press‑cure prepreg protocol, keeping the drying/pressing step below the ~300 °C resin‑to‑ceramic conversion point that '639 itself identifies. The result is predictable, not serendipitous.

Ground 2: US 4,460,639 + US 4,228,270 (or US 4,152,509)

'270 and '509 are directed to borosiloxane/polyborodiphenylsiloxane polymers with expressly recited superior heat resistance and hydrolysis resistance, and expressly proposed as binders for ceramics, surface‑treating agents for glass or carbon fibers, and curing agents for epoxy resins ('270: "excellent as a precursor for silicon carbide or a sintering auxiliary agent or a binder for ceramics such as silicon carbide"; "useful as … a surface treating agent for glass fibers or carbon fibers"). These are direct, explicit suggestions to use borosiloxanes as the binding matrix for a fibrous/ceramic substrate — precisely the '858 matrix function.

Combining either with '639 (which teaches the substrate, the prepreg format, and the ≤300 °C pressing/curing steps) yields claim 1. The motivation is a classic KSR "known technique, known function" case: a POSITA wanting a heat‑resistant binder for a fiber substrate would look to the art the references themselves identify as heat‑resistant binders for ceramics and fiber surface treatment.

Ground 3: US 4,460,639 + US 4,361,679

'679 teaches that adding a metal (including Al) to an organoborosiloxane and heating to ≤550 °C produces a heat‑resistant and moisture‑resistant polyborometallosiloxane. This reference (a) confirms that the borosiloxane family was the recognized route to high‑temperature resin matrices, and (b) supplies a reason to pair the borosiloxane matrix with an alumina fibrous substrate (claim 4) — the metal oxide and the borosiloxane being known co‑operating constituents. Its 550 °C ceiling also brackets the '858 window from above, reinforcing that organic (phenyl) character is retained at low hundreds of degrees.

Ground 4 (single‑reference + common knowledge): US 4,405,687, alone or with the '509/'270/'679 synthesis teachings

'687 already discloses the complete matrix chemistry and a 50:50 polyborosiloxane:silicone‑resin ratio. The only missing element is the prepreg format and the numeric temperature/retention limits. Once a formulator selects '687's composition as a heat‑resistant resin, choosing a drying temperature above the boiling point of its NMP/xylene solvent (≥~200 °C) and below the resin's decomposition/ceramization temperature (~300 °C, known from '639 and inherent in the chemistry) is at most routine optimization of a result‑effective process variable (In re Boesch; In re Aller). Selecting the borosiloxane content at ≥10 wt% is likewise optimization within a range '687 already exemplifies at 50 wt%.

4. Why the "≥20% Si‑phenyl retention" limitation does not save the claims

This is the only element the references do not state numerically, and it is the weakest hook for patentability for four reasons:

1. It is a process/result parameter, not a structural difference. Claim 1 is, in substance, a product‑by‑process claim: the article is defined by the ≥20% retention produced by the 200–300 °C treatment. Under In re Best, where a process limitation does not produce a structurally distinguishable product, it imparts no patentable weight. Any borosiloxane‑matrix prepreg dried in the claimed window necessarily possesses the recited retention — the limitation is inherent in the process, and the burden shifts to the patentee to show a structural difference.

2. The art identifies the very variable and its measurement. '270 expressly assigns the 695 cm⁻¹ IR absorption to the monosubstituted benzene ring (Si‑phenyl) and uses IR absorbance ratios (δ1340/δ695, δ1080/δ695) to quantify resin structure. A POSITA therefore already knew how to measure Si‑phenyl retention; '858's 700 cm⁻¹ δa/δo test is the same measurement at essentially the same wavelength. Discovering the numeric threshold (20%) of a known, art‑recognized variable is not inventive.

3. It is an obvious‑to‑try boundary. The patent's own data (Table 1) show the property degrades monotonically with phenyl loss (δa/δo = 0.3–1.0 → 60–75 kg/cm²; δa/δo = 0.1 → 9 kg/cm²). With a disclosed degradation curve, a POSITA has at most a "finite number of identified, predictable solutions" — KSR. The 20% cutoff is where one would expect performance to fall off; finding it is routine testing.

4. No teaching away. '639's firing at ≥1000 °C is a subsequent ceramic‑formation step, and '639 deliberately keeps its pressing/curing steps at ≤300 °C to preserve a fusible resin — the same direction as '858. The references therefore point toward, not away from, the claimed low‑temperature window. Note that '679's 550 °C bonding step is a metal‑complexation step, not a phenyl‑destruction teaching; at most it reflects a different, higher‑temperature objective and is not a teaching away.

5. Dependent claims

Claims 2–4 and 6 add nothing that rescues the independent claims:

• Claim 2 / claim 6 recite the borosiloxane synthesis. The three‑component reaction of a boric acid source with a silane compound and a silicone oil is disclosed in '687; the diphenylsilanediol + boric acid combination is disclosed in '270 (and '509's Example 5 uses diphenyldihydroxysilane + trimethyl borate). Condensation "at 50–800 °C" overlaps the disclosed 80–140 °C, 200–450 °C, and 250–400 °C working ranges. Where a claimed range overlaps a prior‑art range, prima facie obviousness attaches, and the patentee must show criticality — the '858 spec offers no criticality data for the condensation range, only for the drying range.
• Claim 3 (silicone resin) is the exact co‑resin species '687 exemplifies.
• Claim 4 (alumina fibers) is suggested by '639's Nextel 312 alumina‑boria‑silica fiber and its colloidal Al₂O₃ matrix option, and by '679's use of Al in a heat/moisture‑resistant borosiloxane.

6. Patentee's best counterarguments, and how they cut

Where the patent would most plausibly survive: if the patentee could show (i) that the cited references' borosiloxane systems, when dried in the 200–300 °C window, do not inherently retain ≥20% of Si‑phenyl groups (rebutting In re Best inherency with comparative IR data), or (ii) unexpected, non‑obvious performance at ≥10 wt% borosiloxane relative to a silicone‑resin matrix as taught by '687 rather than relative to epoxy. Neither showing is present in the intrinsic record summarized in the prior sections.

7. Conclusion

On the references cited on the face of the patent, claims 1–6 of US 4,735,858 are vulnerable to a § 103 challenge. The strongest combination is US 4,405,687 (borosiloxane/silicone‑resin matrix, same assignee) in view of US 4,460,639 (fiber‑impregnated prepreg with ≤300 °C press/cure steps), optionally further in view of US 4,228,270 (borosiloxane as a heat‑resistant ceramic/fiber binder; 695 cm⁻¹ Si‑phenyl IR quantification) and US 4,361,679 (Al‑modified borosiloxane for heat/moisture resistance). Every element of the independent claims is disclosed or rendered obvious by routine optimization; the sole unmet element — the numeric ≥20% Si‑phenyl retention — is an inherent consequence of the claimed drying step, measured by a technique the prior art already taught.

Caveats and confidence

• High confidence in the reference identities, dates, owners, and the general subject matter, and in the '858 claim text — those come from the authoritative full text supplied in the page content.
• Moderate confidence in the specific language of the references' claims and examples. My quotations are drawn from the Google Patents / Justia excerpts returned in search (snippets of US 4,405,687, US 4,228,270, US 4,152,509, US 4,361,679, US 4,460,639); I did not retrieve the full column‑and‑line text of, for example, claim 1 of '687 verbatim. Before filing or serving an invalidity contention, the exact pin cites (column/line) should be verified against the official copies at the USPTO Patent Public Search (ppubs.uspto.gov).
• Identifier discipline: the string "4460640" appears in search results alongside "4460639." These are two distinct Dow Corning patents (the sibling pair noted above — '639 uses organosilsesquioxane resin sols; '640 uses thermosetting organopolysiloxane resins). I have not merged them; only US 4,460,639 is the reference cited on the face of '858.
• I have not independently confirmed the examiner's reasons for allowance, so I cannot say whether a specific § 103 combination was considered and overcome. That would require the file wrapper (USPTO PatentCenter / Global Dossier for application US 06/886,794).