Enamel and Glaze Patents: Who Leads, Where the Gaps Are 2026
- Filing has cooled since 2017. the peak filing year in this dataset, with the 2022 midpoint down to a fifth of that level — a maturing, not a growing, claim space.
- The top 5 assignees hold 31.0% of all 281 records. concentrated enough to matter, but with 41.6% held by the top 10, well short of a lockout — there is room to file around the edges.
- C23D (enamelling of metals) sits at just 25.3% of records. well behind the 79.4% covered by core C03C glass and enamel compositions — the metal-substrate process side is comparatively open.
What this landscape covers
This landscape tracks 281 published records filed between 2015 and the 2026 data cut-off, drawn from claims and description text referencing porcelain enamel, ceramic glaze and vitreous enamel coating, filtered to IPC classes covering glass and enamel compositions, enamelling of metals, and ceramics and refractories. The scope favours documents that speak directly to adherence-to-steel, fish-scaling defects, lead- and cadmium-free frit, firing temperature control and chemical resistance — the practical failure modes and formulation constraints that separate a workable enamel from a laboratory curiosity.
Because publication lags filing by roughly eighteen months, the apparent drop-off in the most recent years understates real filing activity; treat the last one to two years of any trend as a floor, not a ceiling. Family counts, not raw document counts, anchor the assignee ranking below, which neutralises the effect of aggressive continuation filing or filing the same invention in multiple jurisdictions.
Filing trend and technology composition
Two views of the same 281 records: how filing activity has moved year over year, and which IPC subclasses the claims actually sit in.
Filing trend: a 2017 peak and a flat-to-declining decade
Filings peaked at 21 in 2017 and had fallen to 5 by the 2022 midpoint, with the trend continuing flat to declining into the most recent, publication-lag-affected years. This is a mature claim space rather than an emerging one: the core chemistry and processing routes have largely been staked out, and new filings increasingly target refinements rather than foundational compositions.
IPC composition: enamel chemistry dominates, metal-substrate process trails
C03C (glass and enamel compositions) appears in 79.4% of the 281 records, making it the backbone of the field, followed by C04B (ceramics, cement and refractories) at 35.6%. C23D (enamelling of metals) — the substrate-adhesion and firing-process side — sits at only 25.3%, and smaller adjacent classes such as B32B (layered products, 5.7%) and C23C (coating and surface deposition, 5.3%) are thinner still. Records can carry more than one class, so these shares add up to well over 100%.
Shares are the percentage of the 281 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Enamel and Glaze Technology with Eureka
This page is one run against one query. Ask Eureka your own question about enamel and glaze technology and every answer comes back with the patent numbers behind it.
Try EurekaMost-cited records and a representative filing
CA2749233A1 — Method for producing a porcelain enamel logo on a porcelain enamel background
The filing describes a multi-firing process: a porcelain enamel base fired over a metal substrate at a first temperature, a cover coat fired at a lower second temperature to set a background colour, and a decal fired at a lower third temperature still, with the decal carrier burning off to leave a fixed, multi-colour porcelain enamel image on the cover coat.Assignee and filing date are rendered from the record above.
View full record| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US5993974A | Porcelain-enameled steel sheets and frits for enameling | 112 |
| 2 | US6303183B1 | Anti-microbial porcelain enamel coating | 110 |
| 3 | US5677250A | Low-temperature lead-free glaze for alumina ceramics | 105 |
| 4 | US5783506A | Ceramic glaze including pearlescent pigment | 85 |
| 5 | US4460630A | Method of forming porcelain enamels on aluminized steel | 73 |
| 6 | EP0916624A1 | Porcelain-enameled steel sheets and frits for enameling | 70 |
| 7 | US4361654A | Porcelain enamel frit for sheet iron ground coat | 65 |
| 8 | CN101921136A | 一种生料哑光釉 | 57 |
| 9 | US6566289B2 | White enamel for aluminized or galvanized steel | 47 |
| 10 | US20070265154A1 | Porcelain Enamel Having A Metallic Appearance | 38 |
Citation counts inside a searched corpus favour older filings, since they have had more time to accumulate citations — read this as a signal of influence on the field, not of current commercial importance.
Patent titles are shown in the language they were filed in, not translated, so that each record stays verifiable against the original filing — a translated title will not match in Eureka or in any national register. Each row carries its publication number; clicking a row searches Eureka by that number.
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Browse MCP servers →What the numbers mean for a filing decision
Three read-outs from the dataset that matter more for strategy than the raw counts on their own.
Leadership is real but not a lockout
The leader holds 25 records outright, and the top five combined account for 31.0% of all 281 records in scope — enough to dominate the most-cited compositions but not enough to close the field. The top ten extend that to 41.6%, leaving well over half of all filings spread across a long tail.
A field past its filing peak
Filing activity peaked at 21 records in 2017 and had fallen to 5 by 2022, with no rebound visible before the data cut-off. Recent-year momentum among the leading assignees shows no growth either, which points to a technology where the dominant compositions were established some years ago.
Process-side claims are thinner than composition claims
Core glass and enamel composition claims under C03C cover 79.4% of records, while the metal-enamelling process side under C23D covers only 25.3%. That gap suggests firing-profile and substrate-adhesion process claims are less thoroughly staked out than frit and glaze chemistry itself.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to enamel and glaze technology, with the prior art for and against each one.
Who holds the claims, and where they are not looking
The ranked leaders span industrial enamel specialists, appliance and cookware manufacturers, and materials suppliers with adjacent frit businesses. None of the recent-year momentum figures show growth, which is consistent with a settled rather than an expanding competitive set.
A single leader well ahead of the field
The top-ranked assignee holds 25 records against a fifth-place figure of 10 and a tenth-place figure of 5 — a steep drop-off after the leader that flattens into a long tail beyond the top ten.
Most of the field sits outside the top ten
With the top 10 combined accounting for 41.6% of all 281 records, the majority of filings belong to assignees outside the ranked leadership — ceramics manufacturers, regional tile and sanitaryware producers, and individual inventors each holding a handful of records.
US and China lead receiving offices, Europe and Japan follow
The United States receives the largest share of filings at 81, ahead of China at 57, EPO at 38 and Japan at 26, with the UK and WIPO/PCT route trailing at 18 and 15 respectively — a filing footprint concentrated in the largest appliance and construction-materials markets.
| Assignee | Recent year | YoY |
|---|---|---|
| Microban Products Company | 0 | — |
| Medtronic Advanced Energy LLC | 0 | -100% |
| Ferro Corporation | 0 | — |
| AOS Holding Company | 0 | — |
| Pemco Brugge BVBA | 0 | — |
| NGK Insulators, Ltd. | 0 | — |
| A. O. Smith Corporation | 0 | — |
| FERRO FRANCE S A R L | 0 | — |
Where to take this next
The landscape narrows down to specific questions once you know where the concentration and the gaps sit.
Check freedom-to-operate against the leading assignees
Run the most-cited compositions and the top-five assignees' active families against a specific frit or firing-profile idea before committing R&D spend.
Explore in Eureka →Scope a filing in the under-claimed process branches
C23D enamelling-of-metals claims trail composition claims by a wide margin — substrate adhesion and multi-firing decal processes are candidates for a first-to-file position.
Explore in Eureka →Track momentum, not just cumulative share
Cumulative leadership figures can mask a flat or declining recent-year trend; pair the ranking with year-over-year filing counts before assuming a competitor is still active.
Explore in Eureka →Common questions on enamel and glaze patents
The dataset ranks 100 assignees by family count, with the leader holding 25 records and the top five combined accounting for 31.0% of all 281 records in scope. That leadership is concentrated among industrial enamel and frit suppliers plus appliance manufacturers with in-house enamelling lines, but it stops well short of a lockout: the top ten still only reach 41.6% of records, leaving most of the field to a long tail of ceramics producers, regional manufacturers and individual inventors. Anyone assessing competitive risk should look at both the leadership figures and the long tail, since a crowded field of small filers can still block a narrow claim even without a dominant single owner.
The filing trend points to maturity rather than growth: activity peaked at 21 records in 2017 and had fallen to 5 by the 2022 midpoint, with no rebound visible before the 2026 data cut-off. Recent-year momentum figures for the leading assignees show no growth either. Because publication lags filing by around eighteen months, the very latest years in any such trend are always undercounted, but the multi-year decline from the 2017 peak is unlikely to be explained by lag alone.
The bulk of records fall under C03C, covering glass and enamel compositions, which appears in 79.4% of the 281 records in scope. C04B, covering ceramics, cement and refractories, follows at 35.6%, and C23D, covering the enamelling of metals process itself, sits at 25.3%. Smaller but relevant adjacent classes include B32B for layered products and C23C for coating and surface deposition, each under 6% of records. Since a single record can carry several IPC classes, these percentages add up to more than 100% and should not be summed.
The clearest gap sits on the process side: C23D, enamelling of metals, covers only 25.3% of records against 79.4% for core C03C composition claims, meaning firing-profile control, substrate pre-treatment and multi-stage decal or logo application are comparatively under-claimed relative to frit and glaze chemistry itself. Chemical-resistance testing protocols and lead- and cadmium-free frit formulations for specific high-temperature firing windows are narrower branches worth checking before filing. None of this should be read as an absence of prior art — it means the density is lower, not zero, so a freedom-to-operate check against the leading assignees' active families is still the necessary next step.
The United States leads with 81 filings, ahead of China at 57, the European Patent Office at 38 and Japan at 26. The United Kingdom and the WIPO/PCT route trail at 18 and 15 respectively. This distribution reflects where the largest appliance manufacturing, construction-materials and ceramics markets sit, and it is a useful guide to where enforcement and freedom-to-operate risk is most concentrated for a company selling enamelled steel or ceramic products into those markets.
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Disclaimer. This page is generated from Patsnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
Nothing on this page constitutes an exhaustive prior-art, novelty, freedom-to-operate, or validity search, nor does it constitute legal, financial, investment, or professional advice, and it should not be relied upon as such. Any patent, commercial, or strategic decision should be verified independently and reviewed with qualified patent, legal, and domain professionals. Patsnap makes no warranties, express or implied, as to the accuracy, completeness, or fitness for any particular purpose of the information presented.
Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company’s registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.