DuPont Pyralux LF7062R combines 0.5 oz rolled-annealed copper with a 1 mil polyimide core for low-profile wearable and medical flex circuits. Full specs, design guidelines, bend radius rules, and biocompatibility notes for PCB engineers.
Walk through the flex circuit specifications for almost any wearable health monitor, compact medical diagnostic device, or body-worn sensor, and a pattern emerges fast: the material requirements cluster around thin dielectrics, light copper weights, and high flex endurance. DuPont Pyralux LF7062R sits precisely in that cluster. It pairs 0.5 oz rolled-annealed copper with a 1 mil Kapton® polyimide core and a 0.5 mil acrylic adhesive — a construction that’s deliberately balanced for the demands of devices worn on the body or embedded in compact medical instruments. This engineering guide covers the full spec picture, the design decisions the 1 mil PI core influences, how LF7062R fits in the single-sided LF family, and the fabrication and application rules that matter most for wearables and medical flex circuit programs.
What Is DuPont Pyralux LF7062R?
DuPont Pyralux LF7062R is a single-sided, acrylic-bonded copper-clad flexible laminate from DuPont’s Pyralux LF product family. The construction places 0.5 oz/ft² rolled-annealed (RA) copper on a 1 mil (25 µm) Kapton® polyimide core, bonded through a 0.5 mil (12.5 µm) C-staged proprietary acrylic adhesive. It is a single-sided grade — one copper layer, one polyimide core, one adhesive layer — supplied in 24 × 36 inch sheet form.
One specification note for engineering teams working under regulated design requirements: LF7062R is not listed as IPC-4204/1 certified in DuPont’s published LF product table. If IPC-4204/1 certification is a hard requirement for your program, review the standard LF family grade options and confirm current status with DuPont or your authorized distributor before specifying.
Decoding the LF7062R Part Number
Understanding DuPont’s Pyralux LF naming convention prevents misreads when comparing grades on a BOM or datasheet:
| Code Segment | Meaning |
| LF | Acrylic-based flexible laminate family (Kapton® PI + proprietary modified acrylic adhesive) |
| 7 | Single-sided copper-clad construction |
| 0 | Single-sided construction group in the LF matrix |
| 6 | 1 mil (25 µm) Kapton® polyimide core |
| 2 | 0.5 mil (12.5 µm) acrylic adhesive layer |
| R | Rolled-Annealed (RA) copper foil |
The copper weight of 0.5 oz/ft² (approximately 17.5 µm / 153 g/m²) is defined within the single-sided product group. The critical comparison: LF7012R (the thinnest LF single-sided grade) uses 0.5 mil PI and 0.5 mil adhesive — LF7062R steps up the PI core to 1 mil while keeping the same 0.5 mil adhesive and the same 0.5 oz copper weight. That single change in PI thickness is enough to alter dimensional stability, minimum bend radius, and how the laminate behaves during multi-step fabrication processes.
Full Material Specifications for DuPont Pyralux LF7062R
The LF7062R laminate uses the same DuPont Kapton® polyimide film chemistry and proprietary acrylic adhesive system throughout the LF family. All Pyralux LF copper-clad laminates arrive fully cured — no additional cure cycle is required during fabrication.
Physical Construction
| Parameter | Specification |
| Copper Type | Rolled-Annealed (RA) |
| Copper Weight | 0.5 oz/ft² (approx. 17.5 µm / 153 g/m²) |
| Adhesive Thickness | 0.5 mil (12.5 µm) |
| Polyimide Core Thickness | 1 mil (25 µm) |
| Construction | Single-sided |
| IPC-4204/1 Certified | No (confirm current status with distributor) |
| Sheet Size | 24 in × 36 in (610 mm × 914 mm) |
| Pack Range | 4 to 25 sheets per pack |
Electrical Properties (Typical Values)
| Property | Value | Test Method |
| Dielectric Constant (1 MHz) | ≤ 3.5 | IPC-TM-650 2.5.5.3 |
| Dissipation Factor (1 MHz) | ≤ 0.04 | IPC-TM-650 2.5.5.3 |
| Surface Resistance | ≥ 10⁶ MΩ | IPC-TM-650 2.5.17 |
| Volume Resistance | ≥ 10⁶ MΩ·cm | IPC-TM-650 2.5.17 |
| Dielectric Strength | ≥ 1000 V/mil | IPC-TM-650 2.5.6 |
These values are consistent with the Pyralux LF family baseline. The composite dielectric for impedance modeling includes the 1 mil Kapton PI (Dk approximately 3.4 at 1 MHz) plus the 0.5 mil acrylic adhesive (Dk approximately 3.0–3.2). Use the full composite Dk — approximately 3.3–3.5 — in impedance calculations, not just the bare PI film value.
The Engineering Logic Behind LF7062R: 0.5 oz Cu on 1 mil PI
To use DuPont Pyralux LF7062R effectively, it helps to understand exactly what it’s solving compared to its nearest LF single-sided relatives. The construction sits between two neighboring grades in a way that’s deliberate.
Why 0.5 oz Copper for Wearables and Medical Flex?
Reducing copper weight from 1 oz to 0.5 oz has two immediate practical effects. First, flex endurance improves substantially. Research on flex fatigue behavior shows that 0.5 oz (17.5 µm) copper can extend dynamic flex cycle life to four or five times that of 1 oz copper at the same bend radius — the thinner foil distributes bending strain across less material cross-section, delaying fatigue crack initiation. For a fitness tracker experiencing thousands of wrist movement cycles per day, or a medical patch worn continuously for 72-hour monitoring periods, this endurance multiplier is a concrete reliability advantage.
Second, the 0.5 oz copper layer is significantly thinner, which reduces the total stackup height and directly enables tighter minimum bend radii. Per IPC-2223, minimum bend radius for single-layer static flex runs approximately 6 × total stackup thickness. Thinner copper cuts that number. For products designed to conform to a wrist, wrap around a finger, or flex with chest movement, every reduction in minimum achievable bend radius expands the design space.
Why 1 mil PI Instead of 0.5 mil PI?
The upgrade from 0.5 mil to 1 mil polyimide core relative to LF7012R is about dimensional stability and fabrication manageability. At 0.5 mil PI, the dielectric substrate has almost no inherent stiffness — it requires careful backing fixtures, tooling support, and process discipline to move through imaging, etching, and coverlay lamination without distortion. Registration across a panel can drift if handling introduces any tension in the thin film.
The 1 mil PI core of LF7062R holds its dimensions better under thermal processing. It has enough stiffness to handle multi-step wet-chemistry fabrication — developer, etchant, rinse, dry — without the excessive handling care that 0.5 mil PI demands. For wearable and medical applications that often require tight trace tolerances, fine-pitch component pads, and precise coverlay window registration, the dimensional stability improvement of 1 mil PI over 0.5 mil PI is a practical fabrication advantage.
The trade-off is a modestly larger minimum bend radius compared to LF7012R. For most wearable and medical applications this trade-off is acceptable — the bend radii involved in a wrist-worn device or a body-contoured patch are rarely so tight that the PI thickness difference between these two grades is the binding constraint.
LF7062R vs. Neighboring Single-Sided LF Grades
Putting LF7062R in the context of the single-sided LF matrix clarifies the design-decision logic:
Pyralux LF Single-Sided Grade Comparison
| Product Code | Cu (oz) | Cu Type | PI (mil) | Adhesive (mil) | IPC-4204/1 |
| LF7012R | 0.5 | RA | 0.5 | 0.5 | No |
| LF7062R | 0.5 | RA | 1 | 0.5 | No |
| LF7004R | 0.5 | RA | 0.5 | 1 | No |
| LF7011R | 1 | RA | 0.5 | 1 | Yes |
| LF8022R | 1 | RA | 1 | 1 | Yes |
| LF8042R | 1 | RA | 2 | 1 | Yes |
LF7062R’s distinctive position: 0.5 oz copper weight — matching LF7012R — combined with a 1 mil PI core that’s twice the thickness of LF7012R’s 0.5 mil substrate, and a 0.5 mil adhesive (thinner than the 1 mil adhesive of LF7004R). It’s the grade that balances light copper, a more fabrication-stable PI core, and the thinnest available acrylic adhesive in the 0.5 oz single-sided range.
Why Rolled-Annealed Copper Matters at 0.5 oz for Dynamic Flex
The “R” in LF7062R is not just a copper type designator — at 0.5 oz foil weight, it’s the reason this grade is appropriate for the demanding dynamic flex conditions that wearable and medical devices impose.
Rolled-annealed copper is produced by mechanical working and annealing of copper strip, aligning grain structure horizontally parallel to the foil plane. This lamellar grain structure disperses bending stress across many crystal planes, giving RA copper elongation values of 20–45% — substantially better than electro-deposited copper’s 4–11% elongation range. At 0.5 oz foil thickness, the copper is already thin enough that even ED copper would perform adequately in low-cycle applications. But for applications demanding tens of thousands to hundreds of thousands of bend cycles — the realistic service life of a wearable health monitor or continuous-monitoring medical patch — research shows rolled-annealed copper at this thickness can maintain integrity through over 90,000 flex cycles compared to roughly 20,000 for ED copper at the same weight and geometry.
That’s not a small margin. For a program where field reliability is non-negotiable and replacement or service isn’t practical, specifying RA copper isn’t a premium — it’s a baseline requirement.
Laminating and Processing Parameters
DuPont Pyralux LF7062R processes under the same standard Pyralux LF laminating conditions:
| Parameter | Range |
| Part Temperature | 182 – 199 °C (360 – 390 °F) |
| Pressure | 14 – 28 kg/cm² (200 – 400 psi) |
| Time at Temperature | 1 – 2 hours |
The acrylic adhesive is fully C-staged at delivery. No additional cure steps are required. Fabricators experienced with other LF grades don’t need process changes to accommodate LF7062R — the standard LF fabrication workflow applies directly.
Practical Fabrication Notes
Panel handling: The 1 mil PI core is stiffer than 0.5 mil PI grades but still requires care during panel conveyance. Maintain appropriate support in wet process lines and minimize unsupported span lengths during conveyance between process steps.
Imaging registration: The 1 mil PI core maintains registration better than 0.5 mil PI through thermal and chemical process steps. Still, monitor panel registration during photolithography qualification runs when moving to LF7062R from heavier PI grades.
Coverlay bonding: DuPont Pyralux LF coverlay — Kapton PI coated with B-staged acrylic adhesive — is the natural companion. Bond under the same temperature and pressure window as the core laminate. Validate adhesion peel strength on thin 0.5 oz constructions during process qualification. For medical device programs, coverlay adhesion testing should be included in design validation documentation.
Trace etching at 0.5 oz: Thin copper requires shorter etch dwell times, which reduces undercutting and produces cleaner trace sidewalls. This supports fine-pitch trace-and-space work typically needed in compact wearable and medical interconnect layouts. Production-stable trace/space minimums of 3/3 mil are achievable with well-controlled etch chemistry on 0.5 oz copper; some fabricators can reliably hit 2/2 mil.
Storage: Maintain in original sealed packaging between 40–85°F (4–29°C), below 70% relative humidity, away from UV and chemical contamination. Kapton polyimide film is hygroscopic — moisture absorption before lamination processing degrades adhesion quality at the coverlay bonding step, a particularly important concern in medical programs where adhesion reliability is part of the quality record.
Current Carrying Capacity at 0.5 oz for Medical and Wearable Circuits
At half-ounce copper weight, LF7062R is suited for signal routing and light power distribution, not heavy current delivery. Using IPC-2152 as the baseline for external conductors in free air at a 10°C temperature rise:
| Trace Width | 0.5 oz Cu Approx. Current |
| 25 mil (0.635 mm) | ~0.6 A |
| 50 mil (1.27 mm) | ~0.9 A |
| 100 mil (2.54 mm) | ~1.4 A |
| 200 mil (5.08 mm) | ~2.2 A |
For wearable health monitors, ECG patches, glucose sensors, and similar medical wearables — where typical trace currents are in the milliamp to low-amp range for sensor excitation, BLE radio supply, and MCU power rails — 0.5 oz copper on LF7062R is entirely adequate. For designs that need genuine power delivery beyond 2–3 A on a single trace, 1 oz copper grades are the appropriate step up.
Design Guidelines for Wearable and Medical Flex on LF7062R
Working on DuPont PCB designs for wearables or medical devices on LF7062R? These design rules apply directly:
Bend Zone Layout for Body-Worn Applications
Route copper traces perpendicular to the bend axis throughout the flex zone. This orientation subjects the foil to pure bending stress — the most favorable loading condition for RA copper’s lamellar grain structure. For wearable devices that flex continuously with body movement, the bend axis is typically well-defined by the product geometry; confirm it with mechanical engineering before locking in the circuit layout.
Keep vias and plated through-holes at least 100 mil (2.54 mm) from the bend tangent line. Copper-plated barrel walls concentrate stress and are documented failure initiation points in flex circuits subjected to repeated bending. In dynamic flex zones, avoid vias entirely if the design permits — through-holes belong in the rigid stiffener areas, not in the flexing region.
For continuous dynamic flex applications like medical wristbands or ECG straps, target a minimum bend radius of at least 10× the total circuit stackup thickness (including coverlay) as a working starting point. Validate against IPC-2223 calculations and perform physical flexure testing at the design validation stage. Accelerated flexure testing — cycling at 10 Hz through the minimum design bend radius — can simulate years of service life in days and catch fatigue issues before production.
Stiffener Design for Component Areas
Body-worn devices require stiffeners at connector pads, component mounting areas, and test points to prevent pad lifting and provide a flat surface for SMT assembly. LF7062R’s 1 mil PI core has minimal mechanical rigidity on its own — stiffeners are not optional in assembled configurations. FR4 stiffener (1.0 mm or 1.6 mm thickness) is standard for most wearable programs; polyimide sheet stiffeners are preferred in applications with wide temperature excursions where CTE mismatch between FR4 and the flex PI creates fatigue at the stiffener edge.
Always position the stiffener edge at least 1.0 mm from the bend tangent and apply strain relief epoxy at the edge to prevent stress concentration at the hard-soft transition.
Biocompatibility and Material Considerations for Medical Flex
Kapton® polyimide film and the DuPont acrylic adhesive system have a long track record in medical electronics. For body-contact applications, the relevant biocompatibility evaluation framework is ISO 10993. DuPont’s Medical Caution Statement (H-50102) should be reviewed for any medical application — DuPont explicitly cautions against use in permanently implantable devices. For external-contact wearable medical devices and short-term skin-contact applications, the polyimide substrate is well-established in the industry.
Surface finish selection for medical flex: ENIG (Electroless Nickel Immersion Gold) is standard for fine-pitch pads, good shelf life, and flat surface topology. For nickel-sensitive applications, discuss ENEPIG or direct immersion gold options with your fabricator. Nickel-free finishes are relevant when the device contacts broken or sensitive skin.
Real-World Application Scenarios for LF7062R
Wearable health monitors (ECG, SpO₂, temperature) — Continuous health monitoring wearables need flex interconnects that survive thousands of daily movement cycles, keep total device profile thin, and operate reliably at the low signal currents typical of biosensor front-ends. LF7062R’s 0.5 oz RA copper and 1 mil PI balance all three requirements.
Medical diagnostic patches — Single-use and multi-use adhesive medical patches for 24–72-hour continuous monitoring (Holter monitors, CGM transmitter patches, fall detection patches) use flex circuits that must conform closely to the skin surface, tolerate repeated patient movement, and stay within aggressive weight and thickness budgets.
Hearing aids and audiology instruments — Hearing aids operate in one of the most space-constrained environments in medical electronics. Flex circuits connecting microphones, processors, and battery management systems in an in-ear or behind-ear form factor are typically built on ultra-thin single-sided flex substrates. LF7062R’s 1 mil PI gives better handling and registration than 0.5 mil PI grades while keeping the overall circuit profile compact.
Fitness wearables and smart garments — Fitness trackers, smart insoles, and e-textile integration circuits that monitor biometrics during athletic activity must survive aggressive dynamic flex during movement. The RA copper at 0.5 oz is the right specification for this fatigue resistance requirement.
Compact industrial sensors — Pressure, temperature, and strain sensors used in tight-clearance industrial environments use single-sided flex for their interconnect tails. LF7062R’s light copper weight and thin total construction keep the interconnect tail compliant and easy to route through constrained passages.
LF7062R vs. Adhesiveless Single-Sided Alternatives
The natural engineering question when specifying LF7062R for medical programs is whether to consider an adhesiveless all-polyimide construction like Pyralux AC instead.
Pyralux AC eliminates the acrylic adhesive bonding layer entirely — copper is cast directly onto the polyimide. This produces a thinner total circuit, higher copper peel strength, better dimensional stability across temperature, and a higher service temperature ceiling. The engineering upgrade to Pyralux AC or similar adhesiveless grades makes sense when the acrylic adhesive system’s thermal limits are binding (approximately 150°C continuous), when the reliability documentation requirements for a medical program specifically require adhesiveless construction data, or when chip-on-flex bare die attachment demands the tighter substrate-to-copper bond that adhesiveless construction provides.
For the broad class of wearable and medical monitoring devices that operate at body temperature with only brief thermal excursions during solder reflow and sterilization (autoclave sterilization is a DuPont contraindication for acrylic-based LF grades — confirm with DuPont for your specific sterilization method), LF7062R provides a cost-effective, fabrication-familiar, and fully capable solution.
Useful Resources for Engineers and Procurement
- DuPont Pyralux LF Official Product Page: dupont.com/electronics-industrial/pyralux-lf.html — full product matrix, datasheet downloads, and regional representative contacts
- Pyralux LF CCL Data Sheet (PDF, EI-10117): DuPont’s authoritative construction table for all LF single-sided and double-sided grades, including LF7062R specifications — available via DuPont directly or authorized distributors such as Insulectro
- IPC-4204 Standard: “Flexible Metal-Clad Dielectrics for Use in Fabrication of Flexible Printed Wiring” — certification framework; confirm LF7062R certification status with DuPont
- IPC-2223: “Sectional Design Standard for Flexible Printed Boards” — the reference standard for bend radius calculations, flex zone trace layout rules, and stiffener design guidance
- IPC-2152: “Standard for Determining Current Carrying Capacity in Printed Board Design” — the basis for 0.5 oz copper trace current calculations referenced in this article
- IPC-6013: “Qualification and Performance Specification for Flexible Printed Boards” — qualification and reliability testing standards for flex circuits in medical and wearable programs
- IPC-TM-650 Test Methods: Electrical, mechanical, and thermal test methods for Pyralux LF laminates — available at IPC.org
- DuPont Medical Caution Statement (H-50102): Available from DuPont — essential reading before specifying any Pyralux material in medical device programs
- DuPont Safe Handling Guide for Pyralux: Available at pyralux.dupont.com — drilling, routing, chemical exposure, and storage procedures
Frequently Asked Questions About DuPont Pyralux LF7062R
Q1: What is the key design difference between LF7062R and LF7012R? Both grades use 0.5 oz RA copper and 0.5 mil acrylic adhesive. The difference is the polyimide core: LF7012R uses 0.5 mil PI, LF7062R uses 1 mil PI. The practical impact is that LF7062R has better dimensional stability during fabrication, handles better in multi-step wet processes, and offers slightly more dielectric thickness for impedance calculations. LF7012R achieves a smaller minimum bend radius and thinner total circuit height. For designs where panel registration and fabrication yield are priorities alongside flexibility, LF7062R is often the better choice. For absolute minimum thickness, LF7012R is the grade to evaluate.
Q2: Is LF7062R suitable for dynamic flex applications like continuous body-worn devices? Yes — the rolled-annealed copper specification is specifically appropriate for dynamic flex. At 0.5 oz, RA copper delivers documented flex cycle endurance of tens of thousands to over 90,000 cycles at typical wearable bend radii, depending on geometry. Always calculate minimum bend radius per IPC-2223 for your specific total stackup including coverlay, and validate with flexure testing during design validation. Dynamic bend-cycle testing at the design stage is standard practice for medical-grade wearable flex circuits.
Q3: What are the biocompatibility considerations for using LF7062R in skin-contact medical devices? Kapton® polyimide film has a well-established track record in medical electronics for non-implantable applications. The relevant framework for skin-contact device biocompatibility evaluation is ISO 10993. DuPont issues a Medical Caution Statement (H-50102) that should be reviewed for any medical application. LF7062R should not be specified for permanently implantable devices. For external-contact wearable monitoring applications, confirm biocompatibility test requirements with your regulatory and quality teams, and verify material compatibility with your specific surface finish and coverlay choices.
Q4: Can LF7062R be used in a rigid-flex construction for a compact medical device? Yes — single-sided LF grades are used as flex cores in rigid-flex assemblies. In a rigid-flex construction, LF7062R would occupy the flexible zone connecting rigid cap layer sections. The 1 mil PI core handles multiple lamination thermal cycles without degradation. For medical device rigid-flex programs, confirm the full stackup design with your fabricator’s DFM review process, and ensure that the adhesive system compatibility between LF7062R and the rigid cap laminate or bondply materials is verified.
Q5: What surface finish is recommended for LF7062R circuits in medical wearable programs? ENIG (Electroless Nickel Immersion Gold) is the most common surface finish for fine-pitch medical wearable flex circuits — it provides excellent shelf life, flat surface topology for SMT component placement, and good wire bondability. For skin-contact areas or applications where nickel sensitivity is a concern, discuss ENEPIG (Electroless Nickel Electroless Palladium Immersion Gold) or direct immersion gold options with your fabricator. Confirm that the chosen surface finish is compatible with your coverlay window design and component assembly process.
Getting LF7062R Right the First Time
DuPont Pyralux LF7062R is a focused solution for a well-defined class of applications: single-sided flex circuits that need the lightest appropriate copper weight for maximum flex endurance, a fabrication-stable 1 mil polyimide core that handles better than 0.5 mil film in multi-step processes, and the thinnest available adhesive layer in the 0.5 oz single-sided LF range. For wearable health monitors, medical diagnostic patches, hearing aids, and compact biosensor interconnects, this construction addresses the core material requirements directly. Specify the RA copper designation deliberately — it is the foundation of the flex cycle endurance the application demands — and validate the design with IPC-2223 bend radius calculations and physical flexure testing before committing to production. These steps distinguish a design that survives its intended service life from one that doesn’t.
