DuPont Pyralux LF9110R — 1 oz RA copper / 1 mil polyimide acrylic-based flex laminate. Full datasheet specs, electrical properties, Dk/Df values, LF vs AP series comparison, fabrication tips, and 5 FAQs from a PCB engineer’s perspective.
If you’ve been designing flexible circuits long enough, you’ve landed on DuPont Pyralux LF9110R at some point — whether you recognized it by name or not. It is one of the most widely used constructions in the entire Pyralux LF acrylic-based product family, and with good reason. The combination of 1 oz rolled-annealed copper, a 1 mil Kapton polyimide film, and a 1 mil modified acrylic adhesive creates a thin, cost-effective single-sided laminate that covers a wide range of standard flex and rigid-flex applications. This article breaks down exactly what LF9110R is, what the datasheet numbers actually mean for your design, and where it fits — and where it doesn’t — compared to the adhesiveless AP series and other LF constructions.
What Is DuPont Pyralux LF9110R?
DuPont Pyralux LF9110R is a single-sided, acrylic-based copper-clad laminate from DuPont’s Pyralux LF product family. The LF series has been the industry standard for high-reliability flexible circuit laminate for over 35 years, and LF9110R is the thinnest single-sided construction in the standard lineup.
Decoding the product code: “LF” identifies the acrylic adhesive family; “91” specifies 1 oz/ft² (35 µm) RA copper; “1” identifies the 1 mil (25 µm) Kapton polyimide film thickness; the trailing “0” indicates a single-sided construction with no copper on the reverse face; and “R” confirms rolled-annealed copper foil. The result is a three-layer laminate: 1 oz RA copper / 1 mil acrylic adhesive / 1 mil Kapton polyimide.
This distinguishes LF9110R immediately from DuPont’s adhesiveless AP series. Where AP constructions bond copper directly to polyimide without any intermediate layer, LF9110R uses a C-staged modified acrylic adhesive as the bonding layer between the copper foil and the Kapton film. That architectural choice is the single most important design consideration when deciding whether LF9110R or an AP construction is the right call for a given application — and it cuts both ways, as explained below.
LF9110R Construction Summary
| Parameter | LF9110R Value |
| Product Code | LF9110R |
| Laminate Family | Pyralux LF (Acrylic-Based) |
| Construction Type | Single-sided copper-clad |
| Copper Foil | 1 oz/ft² (35 µm) RA |
| Adhesive Layer | 1 mil (25 µm) modified acrylic (C-staged) |
| Polyimide Film | 1 mil (25 µm) DuPont Kapton |
| Total Nominal Thickness | ~3 mil (75 µm) without copper plating |
| Copper Type | Rolled-Annealed (RA) |
| IPC Certification | IPC-4204/1 |
| UL Listing | UL 796 |
| Quality System | ISO 9001:2015 |
LF9110R Full Datasheet: Electrical and Physical Properties
The following data is drawn from DuPont’s official Pyralux LF Copper-Clad Laminate Technical Data Sheet, tested to IPC-TM-650 and ASTM methods where specified. All values are typical for the LF9110R construction (1 oz RA Cu / 1 mil adhesive / 1 mil Kapton).
LF9110R Electrical Properties
| Property | LF9110R Typical Value | Test Method |
| Dielectric Constant (Dk) @ 1 MHz | 3.6 | IPC-TM-650 2.5.5.3 |
| Dielectric Constant (Dk) @ 10 GHz | 3.0 | ASTM D2520 |
| Loss Tangent (Df) @ 1 MHz | 0.02 | IPC-TM-650 2.5.5.3 |
| Loss Tangent (Df) @ 10 GHz | 0.02 | ASTM D2520 |
| Dielectric Strength | ≥137 kV/mm (3,500 V/mil) | ASTM D-149 |
| Volume Resistivity | ≥10⁹ MΩ-cm | ASTM D-257 |
| Surface Resistivity | ≥10⁸ MΩ | ASTM D-257 |
| Insulation Resistance (ambient) | ≥10⁶ MΩ | IPC-TM-650 2.6.3.2 |
LF9110R Mechanical and Thermal Properties
| Property | LF9110R Typical Value | Test Method |
| Peel Strength after lamination | 1.8 N/mm (10.0 lb/in) | IPC-TM-650 2.4.9 |
| Peel Strength after solder | 1.6 N/mm (9.0 lb/in) | IPC-TM-650 2.4.9 |
| Solder Float Resistance (288°C) | Pass (10 sec) | IPC-TM-650 2.4.13 |
| Dimensional Stability | ≤ +0.10% (MD/TD) | IPC-TM-650 2.2.4 |
| Adhesive Flow | ≤ 4.2 µm/µm (mil/mil) | IPC-TM-650 2.3.17.1 |
| Flammability | VTM-0 | UL94 |
| Max Operating Temperature | ~150°C continuous | — |
| Lamination Temperature Range | 182–199°C (360–390°F) | DuPont Process Guide |
| Lamination Pressure | 14–28 kg/cm² (200–400 psi) | DuPont Process Guide |
| Lamination Time | 1–2 hours at temperature | DuPont Process Guide |
| Storage Temperature | 4–29°C (40–85°F) | DuPont Safe Handling Guide |
| Storage Humidity | Below 70% RH | DuPont Safe Handling Guide |
| Shelf Life (sealed) | 2 years | DuPont warranty |
The Role of the Acrylic Adhesive in LF9110R Construction
The acrylic adhesive layer is what defines the entire Pyralux LF family — and it is the aspect of LF9110R that most often prompts questions from engineers making a first comparison against AP-series adhesiveless laminates. Here is what you need to know about it at a practical level.
The adhesive in LF9110R is a C-staged (fully cured) modified acrylic that has been the subject of more than 35 years of field qualification in demanding applications. DuPont describes it as delivering high bond strength, high thermal resistance, halogen-free chemistry, and low outgassing — with NASA outgassing data available — along with no refrigeration requirement for storage and the ability to withstand multiple lamination cycles without degradation.
For the vast majority of single-layer flex and low-layer-count rigid-flex applications, the acrylic adhesive system is entirely adequate. The peel strength numbers in the table above — 1.8 N/mm as-laminated and 1.6 N/mm post-solder — are genuine high-bond-strength values that provide a reliable copper-to-dielectric interface through normal assembly and service conditions.
Where the adhesive layer becomes a design constraint is in specific high-performance scenarios. The Dk of the acrylic adhesive (~3.6 at 1 MHz) is slightly higher than the Kapton film itself, and the Df of 0.02 is one order of magnitude higher than the AP-series all-polyimide construction (Df ~0.002). For signal-integrity-critical designs running GHz-range differential pairs, that loss tangent difference is meaningful. Similarly, the acrylic adhesive layer adds a CTE-mismatched component to the Z-axis stack that matters in high-cycle thermal environments. When those trade-offs are acceptable — which they are across a large range of standard applications — LF9110R is the economical and practical choice. When they are not, that is the design space where a DuPont PCB using AP-series adhesiveless laminate earns its cost premium.
Understanding LF9110R’s Place in the Pyralux LF Single-Sided Lineup
LF9110R is the thinnest-core single-sided construction in the standard LF series. The table below shows the full single-sided LF 1 oz RA copper family with varying Kapton thicknesses, plus a double-sided reference.
Pyralux LF Single-Sided 1 oz RA Copper Series
| Product Code | Cu Weight | Adhesive | Kapton | IPC Cert | Primary Use Case |
| LF9110R | 1 oz (35 µm) | 1 mil (25 µm) | 1 mil (25 µm) | Yes | Thinnest profile, compact flex |
| LF9120R | 1 oz (35 µm) | 1 mil (25 µm) | 2 mil (51 µm) | Yes | Standard thin single-sided flex |
| LF9130R | 1 oz (35 µm) | 1 mil (25 µm) | 3 mil (76 µm) | Yes | Moderate rigidity flex zone |
| LF9140R | 1 oz (35 µm) | 1 mil (25 µm) | 4 mil (102 µm) | Yes | Stiffer flex, wider traces |
| LF9150R | 1 oz (35 µm) | 1 mil (25 µm) | 5 mil (127 µm) | Yes | Flex-to-install applications |
| LF9210R | 1 oz (35 µm) | 2 mil (51 µm) | 1 mil (25 µm) | Yes | Thicker adhesive, higher peel |
| LF9220R (DS) | 1 oz (35 µm) | 1 mil / 1 mil | 2 mil (51 µm) | Yes | Double-sided equivalent |
The 1 mil Kapton in LF9110R gives the thinnest overall laminate profile in the single-sided LF family. This is useful when total flex zone thickness needs to be minimized — for example, in camera modules, wearable medical devices, or compact consumer electronics where the flex circuit must clear tight mechanical envelopes. The trade-off is that a 1 mil Kapton base provides less dimensional stability and handling stiffness than a 2 or 3 mil Kapton construction, which affects panel-level fabrication handling.
Where LF9110R Gets Specified in Real Designs
The broad application range of the Pyralux LF family reflects the fact that the acrylic-based three-layer construction is a mature, well-understood technology with extensive qualification data behind it.
Consumer Electronics Flex Interconnects — Camera modules, display connectors, keyboard flex cables, and earphone flex assemblies are among the highest-volume uses of LF-series laminates. The combination of thin overall profile, reliable peel strength, and competitive material cost make LF9110R the standard specification across much of this sector.
Medical Devices (Non-Implant) — Handheld diagnostic devices, blood glucose monitors, hearing aid flex circuits, and wearable biosensors frequently use LF-series laminates. DuPont explicitly cautions against use in permanent implantable medical applications; for all other medical applications, the LF series is a common and qualified choice with NASA low-outgassing data available.
Automotive Interior Flex Circuits — Instrument cluster flex cables, seat sensor circuits, and HVAC control panel interconnects that do not reside in under-hood high-temperature environments commonly use LF9110R and similar LF constructions. The 150°C continuous operating temperature limit needs to be respected in thermal zone planning for automotive designs.
Industrial Sensor and Control Flex — Factory automation sensors, industrial robot arm flex interconnects for light signal routing, and control panel flex assemblies that prioritize cost and proven reliability over extreme temperature performance are natural fits for the LF series.
Low-Layer-Count Rigid-Flex — Single or double flex cores in a 4–6 layer rigid-flex assembly where the signal layers are not operating above a few hundred MHz and the thermal environment is moderate represent the volume production sweet spot for LF9110R as a flex core material.
LF9110R vs. AP Series: When to Use Which
This is the specification decision that comes up most often for engineers evaluating DuPont Pyralux LF9110R against adhesiveless alternatives. The table below summarizes the key trade-offs.
LF9110R (Acrylic) vs. AP Series (Adhesiveless) Comparison
| Design Parameter | LF9110R (Acrylic) | AP Series (Adhesiveless) |
| Adhesive Layer | Yes — modified acrylic | None |
| Dk (1 MHz) | 3.6 | ~3.4 |
| Df (1 MHz) | 0.02 | ~0.002 |
| Max Operating Temp | ~150°C | 180°C continuous |
| CTE Z-axis | Higher (adhesive adds Z-stress) | Lower, more stable |
| Peel Strength | 1.8 N/mm (as-laminated) | ≥1.4 N/mm (typical) |
| Material Cost | Lower | Higher |
| Availability | Wide, standard stock | Wide, standard stock |
| High-Freq Performance | Moderate | Excellent |
| Thermal Cycling Stress | Adhesive interface adds CTE discontinuity | No adhesive CTE discontinuity |
| Dynamic Flex (RA) | Yes — RA copper | Yes — RA copper |
The short version: if your design operates below a few hundred MHz, runs in moderate thermal environments, and does not require the last fraction of dielectric performance, LF9110R is the economically practical choice with a 35+ year qualification track record. When GHz-range signal integrity, extreme thermal cycling, or maximum operating temperature above 150°C is the requirement, that is when the AP series adhesiveless construction earns its place in the stack-up.
Fabrication and Processing Notes for LF9110R
LF9110R is processed using standard flexible circuit fabrication techniques. Key process-specific notes for the LF9110R construction follow.
Lamination — The C-staged acrylic adhesive is fully cured; no post-lamination cure is required for the clad itself. When bonding LF9110R into multilayer constructions using LF sheet adhesive or LF bondply, follow the DuPont-specified lamination conditions: 182–199°C at 14–28 kg/cm² for 1–2 hours at temperature. Adequate area ventilation is required during press operations, as trace impurities in the B-staged adhesive components used in bonding layers can volatilize at press temperatures.
Etching — Standard wet chemical subtractive etching for 1 oz copper applies. The 1 mil Kapton backing requires appropriate chemical resistance checks for etchant exposure time if through-holes in the polyimide base are required.
Panel Handling — With a 1 mil Kapton base, LF9110R panels are among the most delicate in the LF family. Copper edges on thin clad panels are sharp; handle with clean cotton or nitrile gloves and use appropriate edge protection. Do not allow unsupported panel spans to exceed handling limits that risk crease damage to the thin polyimide film.
Drilling — When mechanical drilling is required for plated-through-hole constructions incorporating LF9110R cores, provide adequate vacuum at the drill head to capture polyimide dust in accordance with the DuPont Safe Handling Guide.
Useful Resources for Engineers Specifying DuPont Pyralux LF9110R
- DuPont Pyralux LF Official Product Page — dupont.com/electronics-industrial/pyralux-lf.html — The primary source for the current Technical Data Sheet (EI-10117), product selector, and processing guide downloads. Always verify you are working from the latest revision.
- DuPont Pyralux LF CCL Technical Data Sheet (EI-10117, PDF) — Available via the DuPont website and authorized distributors including Insulectro, Cirtech Electronics, and Suntech Circuits. Contains the full LF single-sided and double-sided product code tables, complete electrical and mechanical property data, and lamination condition specifications.
- DuPont Pyralux LF & FR Safe Handling Guide (H-46862) — Covers storage conditions (4–29°C, below 70% RH), shelf life, lamination ventilation requirements, and drill/route dust management for all LF series materials.
- DuPont Pyralux Flexible Composites Technical Manual — The comprehensive processing reference for all Pyralux LF materials, covering lamination profiles, via processes, coverlay application, and rigid-flex construction techniques. Available from your DuPont sales representative.
- IPC-4204/1 — The IPC specification to which LF9110R is certified. Reference when writing incoming inspection criteria, supplier qualification documents, or quality plans.
- IPC-2223 — Sectional design standard for flexible printed boards. Contains conductor spacing rules, bend radius guidelines, dynamic flex design rules, and via structure requirements directly applicable to LF9110R-based designs.
- NASA Low-Outgassing Data — DuPont reports NASA low-outgassing data availability for Pyralux LF materials; this data is particularly relevant for aerospace and vacuum-environment applications where outgassing qualification is required.
Frequently Asked Questions About DuPont Pyralux LF9110R
Q1: What is the difference between LF9110R and LF9110E? The only difference is the copper foil type. LF9110R uses rolled-annealed (RA) copper, which has a grain structure parallel to the foil surface and superior flex fatigue resistance. LF9110E uses electro-deposited (ED) copper, which has a columnar grain structure better suited to fine-line imaging but inferior fatigue life under cyclic flex stress. For any application with a dynamic flex zone or repeated installation bending, LF9110R is the correct choice. For static flex where fine line widths and cost optimization are the priority, LF9110E may be considered. DuPont also offers LF9110ED — a double-treated RA copper variant (nodules on both copper faces) for applications requiring enhanced peel strength.
Q2: Can LF9110R be used as a flex core inside a multilayer rigid-flex stack-up? Yes, it is one of its standard use cases. LF9110R single-sided flex cores can be incorporated into multilayer rigid-flex constructions using LF sheet adhesive or LF bondply for interlayer bonding. The thin 1 mil Kapton construction minimizes total stack thickness when multiple flex cores are required. Be aware of the CTE mismatch consideration between the acrylic adhesive layers and the Kapton film when designing for high-cycle thermal environments; consult the DuPont Pyralux Technical Manual for multilayer lamination recommendations.
Q3: Is LF9110R halogen-free? Yes. DuPont confirms the Pyralux LF acrylic-based flexible circuit materials are halogen-free. They do not contain polybrominated biphenyls (PBBs) or polybrominated biphenyl oxides (PBBOs). This is relevant for RoHS compliance and for designs targeting environmental standards that restrict halogenated flame retardants.
Q4: What is the maximum continuous operating temperature for LF9110R? The maximum continuous operating temperature for LF-series acrylic-based laminates is approximately 150°C. This is lower than the 180°C continuous rating of the adhesiveless AP series, reflecting the thermal limitations of the acrylic adhesive component. For designs operating near or above 150°C continuously — such as under-hood automotive applications, high-power RF modules, or aerospace avionics — the AP adhesiveless series is the more appropriate material family.
Q5: How does the Dk of LF9110R compare to the AP series for controlled impedance design? LF9110R has a Dk of 3.6 at 1 MHz, dropping to approximately 3.0 at 10 GHz. The AP-series adhesiveless constructions have a Dk of approximately 3.4 at 1 MHz with more stable frequency behavior due to the absence of an adhesive layer. For most controlled impedance designs operating below 1 GHz, the Dk difference is small enough that standard microstrip or stripline calculations using the LF9110R Dk value will yield accurate trace width targets. For designs operating at several GHz, the frequency-dependent Dk shift from 3.6 to 3.0 should be taken into account in simulation, and the higher Df of 0.02 versus the AP series 0.002 will produce noticeably higher insertion loss at GHz frequencies. For those applications, the AP series is the correct choice.
