DuPont Pyralux LF9110E: Engineer’s Complete Guide to the ED Copper Acrylic Flex Laminate — Specs and Comparison to LF9110R

When a fabrication engineer or purchasing manager types “LF9110E” into a search, they are almost never asking a purely abstract material question. They have a print in front of them that calls out LF9110E specifically, or they are evaluating whether to switch from LF9110R to LF9110E on a current program, or they want to understand precisely what the “E” suffix changes before approving a design. This guide answers all three versions of that question. DuPont Pyralux LF9110E is the electro-deposited copper variant of the well-established LF9110 single-sided acrylic flex laminate — identical in every dimension to LF9110R except for the copper foil type — and the practical engineering implications of that single substitution are worth understanding clearly before you specify either variant.

Decoding the DuPont Pyralux LF9110E Part Number

DuPont’s Pyralux LF naming convention confirms that the product code suffix specifies copper type: add “R” to the end of the code to specify rolled-annealed copper (e.g., LF9210R), add “E” to the end of the code to specify electro-deposited copper (e.g., LF9210E). Applied to the LF9110 construction, that gives:

Code Segment	What It Encodes	LF9110E Value
LF	Acrylic-based laminate family	C-staged modified acrylic adhesive construction
9	Copper weight designator	1 oz/ft² (35 µm) copper
1	Product series designator	LF 1 oz copper series
1	Kapton thickness designator	1 mil (25 µm) Kapton polyimide
0	Layer structure designator	Single-sided clad
E	Copper foil type	Electro-Deposited (ED) copper

The “0” in the fifth position confirms this is a single-sided construction — copper on one face only — distinguishing it from LF9111E, the double-sided equivalent. Every physical dimension of the laminate is identical to LF9110R: 35 µm copper / 25 µm acrylic adhesive / 25 µm Kapton polyimide. The copper foil type is the sole difference between the two variants, and it affects specific performance characteristics in ways that matter in certain applications while being irrelevant in others.

LF9110E Full Construction Overview

DuPont Pyralux LF copper-clad laminated composites are constructed of DuPont Kapton polyimide film with copper foil on one or both sides, bonded together with a proprietary C-staged modified acrylic adhesive. All copper-clad laminates are available with rolled, annealed copper or electro-deposited copper. For LF9110E, the construction breaks down as follows:

LF9110E Three-Layer Stack Dimensions

Layer	Material	Thickness
Conductor	1 oz (35 µm) Electro-Deposited copper	35 µm
Adhesive	C-staged modified acrylic adhesive	25 µm (1 mil)
Dielectric	DuPont Kapton polyimide film	25 µm (1 mil)
Total core		~85 µm

This is precisely the same total stack thickness as LF9110R. The 85 µm core before coverlay application is a confirmed structural fact for both variants.

DuPont Pyralux LF9110E Full Technical Specifications

All dielectric and laminate-level properties for the LF9110E are identical to LF9110R — they share the same Kapton film, acrylic adhesive formulation, and lamination conditions. The only property differences are those that derive directly from the copper foil type, which are addressed in the comparison section below.

Electrical Properties (LF Series — Both E and R Variants)

Property	Value	Frequency	Test Method
Dielectric Constant (Dk)	3.6	1 MHz	IPC-TM-650 2.5.5.3
Dielectric Constant (Dk)	3.0	10 GHz	ASTM D2520
Loss Tangent (Df)	0.02	1 MHz	IPC-TM-650 2.5.5.3
Loss Tangent (Df)	0.02	10 GHz	ASTM D2520
Volume Resistivity	>10¹⁵ Ω·cm	—	IPC-TM-650 2.5.17
Surface Resistance	>10¹⁴ Ω	—	IPC-TM-650 2.5.17

Mechanical and Adhesion Properties

Property	LF9110E Value	Test Method
Peel Strength (after lamination)	1.8 N/mm (10 lb/in)	IPC-TM-650 2.4.9
Peel Strength (after solder)	1.6 N/mm (9 lb/in)	IPC-TM-650 2.4.9
Dimensional Stability (MD/TD)	±0.10%	IPC-TM-650 2.2.4
Solder Float (288°C, 10 s)	Pass	IPC-TM-650 2.4.13

Lamination Process Conditions

Parameter	Value
Part Temperature	182–199°C (360–390°F)
Pressure	14–28 kg/cm² (200–400 psi)
Time	1–2 hours at temperature

Compliance and Certifications

Standard	Status
IPC-4204/1	Certified
RoHS	Compliant
ISO 9001:2015	Manufactured under certified QMS
Certificate of Conformance	Available with every batch

The One Variable: ED Copper vs. RA Copper — What Actually Changes

This is the core engineering content that every engineer searching for LF9110E needs. The laminate properties are identical between LF9110E and LF9110R. What changes is every property that flows from the copper foil’s grain structure and surface morphology.

Grain Structure: Columnar vs. Laminar

Rolled-annealed copper is produced by mechanically rolling copper ingot to foil thickness and then annealing it, which produces elongated, horizontal (laminar) grain structure parallel to the foil surface. Electro-deposited copper is grown electrochemically, producing columnar grains that grow vertically through the foil thickness. This structural difference underpins every performance difference between LF9110E and LF9110R.

Flex Fatigue Life: RA Wins Outright

For dynamic flex applications — any design where the circuit bends repeatedly during product operation — rolled-annealed copper is the unequivocal choice. The RA copper’s laminar grain structure allows the foil to deform and recover under cyclic bending without initiating fatigue cracks at grain boundaries. ED copper’s columnar grain boundaries run perpendicular to the bending stress in a flex circuit, providing potential crack initiation sites under repeated cycling.

The practical rule used throughout the flex PCB industry is clear: RA copper is essential for dynamic flex applications, while ED copper suits static flex only. On LF9110E, the ED copper foil applies that constraint to the full LF9110 construction — a design that would function reliably through thousands of flex cycles on LF9110R may show premature copper cracking on LF9110E under the same bending conditions.

Fine-Pitch Etch Resolution: ED Has the Advantage

The one area where ED copper outperforms RA copper in a practical fabrication context is fine-pitch etching at standard copper weights. ED copper’s columnar grain structure produces a more uniform etch front across the copper depth, yielding more consistent trace sidewall geometry and lower within-panel trace width variation at sub-3 mil (75 µm) trace widths. For circuit designs on LF9110E that include fine-pitch signal traces at or below 3 mil / 75 µm, ED copper’s etch behaviour is an advantage over RA copper’s laminar structure at the same copper weight.

This advantage is proportionally more significant at lower copper weights (9–18 µm), where it drives material selection decisions in products like the AP7156E and AP7125E. At 1 oz (35 µm) — as in LF9110E — the fine-pitch etch advantage of ED copper is real but less decisive than at ultra-thin foil weights.

Surface Roughness and High-Frequency Insertion Loss

RA copper’s mechanical rolling process produces a smoother surface than the electrodeposition process used to create ED copper foil. Smoother copper surfaces mean lower resistive losses at high frequencies, where current flows predominantly on the conductor surface due to the skin effect. Above approximately 2–3 GHz, the surface roughness difference between RA and ED copper at 1 oz weight becomes a measurable contributor to insertion loss. For LF9110E, this is largely academic — the acrylic adhesive’s Df of 0.02 dominates insertion loss behaviour at all frequencies well before copper surface roughness becomes the limiting factor.

Double-Treated (D) Variant: A Third Option Worth Knowing

Both RA and ED types are available with double-treated copper — nodules of electro-deposited copper on both sides of the copper foil. Double-treated copper, if used, eliminates surface preparation steps prior to resist or coverlay lamination. The double-treated RA variant is specified as LF9110D — it delivers RA copper’s flex endurance with improved adhesion surface for resist lamination, eliminating the mechanical surface preparation step that some fabricators apply to standard RA foil before imaging. LF9110D is worth considering when production throughput is a priority and dynamic flex endurance is also required.

LF9110E vs. LF9110R: Complete Side-by-Side Comparison

This is the table most engineers searching for LF9110E are actually looking for. Every confirmed difference between the two variants is captured here:

Parameter	LF9110E (ED Copper)	LF9110R (RA Copper)	LF9110D (Double-Treated RA)
Copper type	Electro-Deposited (ED)	Rolled-Annealed (RA)	Double-Treated RA
Copper thickness	35 µm (1 oz/ft²)	35 µm (1 oz/ft²)	35 µm (1 oz/ft²)
Adhesive	1 mil acrylic	1 mil acrylic	1 mil acrylic
Kapton	1 mil / 25 µm	1 mil / 25 µm	1 mil / 25 µm
Total core	~85 µm	~85 µm	~85 µm
Dk @ 1 MHz	3.6	3.6	3.6
Df @ 1 MHz	0.02	0.02	0.02
Peel strength	1.8 N/mm	1.8 N/mm	1.8 N/mm
Dynamic flex life	Lower	Higher	Higher
Fine-pitch etch	Better (columnar grain)	Good	Good
Surface roughness	Higher	Lower	Lower
Pre-lamination surface prep	May be reduced	Standard	Eliminated
Relative cost	Similar	Baseline	Slightly higher
Static flex	Yes	Yes	Yes
Dynamic flex	Not recommended	Yes	Yes
IPC-4204/1	Certified	Certified	Certified

The conclusion from this table is clean: if the design has any dynamic flex requirement — repeated bending during product operation — specify LF9110R or LF9110D, never LF9110E. If the design is static flex or bend-once-during-installation, and fine-pitch trace resolution is a priority, LF9110E is a legitimate choice.

Where LF9110E Fits in the Full Pyralux LF Family

DuPont Pyralux LF products are acrylic-based copper clad laminates, coverlays, bondplys and sheet adhesives and have been the industry standard in high reliability applications for over 35 years with a proven record of consistency and dependability. LF9110E is one construction within a broad product family that covers a wide range of copper weights and Kapton thicknesses.

Standard LF Single-Sided Clad — E Variants Available

Product Code (RA/E)	Cu (oz / µm)	Adhesive (mil)	Kapton (mil)	Total Core
LF7012R / LF7012E	0.5 oz / 18 µm	0.5 mil	0.5 mil	~44 µm
LF7062R / LF7062E	0.5 oz / 18 µm	0.5 mil	1.0 mil	~56 µm
LF9110R / LF9110E	1 oz / 35 µm	1 mil	1 mil	~85 µm
LF9120R / LF9120E	1 oz / 35 µm	1 mil	2 mil	~111 µm
LF9150R / LF9150E	1 oz / 35 µm	1 mil	5 mil	~197 µm
LF9210R / LF9210E	2 oz / 70 µm	1 mil	1 mil	~120 µm
LF9220R / LF9220E	2 oz / 70 µm	1 mil	2 mil	~146 µm

Every construction in the LF single-sided family is available in both RA (“R”) and ED (“E”) copper variants by appending the correct suffix to the product code. The dielectric, adhesive, and laminate-level properties are identical across both variants for any given construction.

Real-World Applications for DuPont Pyralux LF9110E

Understanding LF9110E’s correct application domain is best approached by asking: where does ED copper provide a functional advantage over RA copper in a static-flex context on a standard acrylic LF laminate?

High-Density Static FPC Signal Routing

The primary practical scenario where LF9110E is preferred over LF9110R is high-density single-sided FPC designs at trace/space below 3 mil (75 µm). Circuit designs on LF9110E that include fine-pitch signal traces benefit from ED copper’s more consistent etch behaviour at these dimensions, particularly in large-panel production where within-panel trace width variation has direct yield impact. Display driver FPCs, dense sensor signal cables, and compact connector breakout flex circuits with sub-75 µm features are the right application home for LF9110E.

Rigid-Flex Inner Layers Where Dynamic Flex Is Not Required

Pyralux LF laminated composites are typically used to produce high reliability, high density circuitry of flexible, rigid-flex, and all-flexible multilayer constructions. In a multilayer rigid-flex board where the flex zone’s LF9110 layer is a static inner core — carrying signals through a flex region that bends once during assembly installation but does not flex during product operation — LF9110E is a viable inner-layer material. The ED copper provides consistent etch geometry on fine-pitch inner-layer routing without the flex fatigue lifetime penalty, because the static flex condition does not cycle the copper.

Static Sensor Flex Interconnects and Industrial Control FPCs

Industrial sensor ribbon cables, HVAC system control flex circuits, and machine instrument panel FPCs that are installed with a single-installation bend and never move again are appropriate applications for LF9110E where the cost profile and ED etch behaviour are advantages and the dynamic flex restriction is not a constraint.

Camera Module and Display Backlight Static Cables

Smartphone display backlight flex cables, fixed-position camera module signal cables (where the cable is bent once into position during phone assembly and never flexed again), and static display ribbon interconnects are all static flex applications where LF9110E functions equivalently to LF9110R and where fine-pitch density may make ED copper a preferred fabrication choice.

Fabrication and Design Guidance for LF9110E

Fabrication of LF9110E follows standard Pyralux LF processing procedures. Lamination conditions for DuPont Pyralux LF flexible circuit materials are typically: part temperature 182–199°C (360–390°F), pressure 14–28 kg/cm² (200–400 psi), time 1–2 hours at temperature. No process changes are required at the lamination stage when substituting LF9110E for LF9110R.

Bend Radius: Tighter Limits for ED Copper

Total finished circuit thickness for LF9110E with standard 25 µm film polyimide coverlay on the copper face:

Layer	Thickness
Coverlay (PI film + acrylic adhesive)	~50 µm
Copper (1 oz ED)	35 µm
Acrylic adhesive	25 µm
Kapton polyimide	25 µm
Total finished thickness	~135 µm

Applying IPC-2223 guidance — noting ED copper is for static flex only:

Flex Type	Multiplier	LF9110E Min. Bend Radius	Notes
Static — one-time bend	6× total thickness	~0.8 mm	ED copper acceptable
Limited-cycle (<100 cycles)	10× total thickness	~1.4 mm	Evaluate carefully
Dynamic flex (repeated)	Not recommended	—	Use LF9110R instead

Apply the static bend radius with conservative margin on LF9110E. Unlike LF9110R, there is no safety buffer for unintended repeated flexing — if the installation process will bend the circuit more than a handful of times, specify LF9110R.

Trace Width and Current Capacity at 1 oz ED Copper

The current-carrying capacity of 1 oz ED copper is functionally identical to 1 oz RA copper for DC and low-frequency applications. Sheet resistance is the same (approximately 0.49 mΩ/square at 35 µm copper). The high-frequency insertion loss difference due to surface roughness is relevant only above ~2 GHz and is masked by the acrylic adhesive’s Df = 0.02 loss at all frequencies in any case.

Trace Width	Max Continuous Current (External, 1 oz, 20°C rise)
0.5 mm (20 mil)	~1.1 A
1.0 mm (39 mil)	~1.8 A
2.0 mm (79 mil)	~2.8 A
3.0 mm (118 mil)	~3.7 A
5.0 mm (197 mil)	~5.2 A

Pre-Assembly Moisture Bake-Out

As with all Pyralux LF constructions, bake LF9110E assemblies at 120°C for a minimum of 4 hours before reflow soldering, and process within 8 hours of bake completion. The Kapton polyimide film in the LF9110E absorbs moisture identically to LF9110R — the copper foil type has no influence on moisture uptake behaviour. Skipping the pre-bake is a reliable path to delamination and blistering defects during lead-free reflow regardless of copper variant.

Storage Requirements

Pyralux LF Copper-Clad Laminate should be stored in the original packaging at temperatures of 4–29°C (40–85°F) and below 70% humidity. The product should not be frozen and should be kept dry, clean, and well-protected. The two-year warranty from date of shipment applies when these conditions are maintained. Certificate of Conformance is available with every batch for both LF9110E and LF9110R.

LF9110E vs. Competing ED Copper Acrylic Flex Laminates

Parameter	LF9110E (DuPont)	Shengyi SHE-FLEX 1oz ED	Generic Acrylic PI Flex ED	LF9110R (DuPont, for reference)
Cu type	1 oz / 35 µm ED	1 oz / 35 µm ED	1 oz / 35 µm ED	1 oz / 35 µm RA
Adhesive	1 mil acrylic	~1 mil acrylic	~1 mil acrylic	1 mil acrylic
Kapton	1 mil / 25 µm	~25 µm	~25 µm	1 mil / 25 µm
Dk @ 1 MHz	3.6	~3.5–3.7	~3.5–4.0	3.6
Df @ 1 MHz	0.02	~0.02–0.03	~0.02–0.04	0.02
IPC-4204/1	Certified	Varies	Varies	Certified
ISO 9001:2015	Full DuPont QMS	Factory-dependent	Factory-dependent	Full DuPont QMS
Lot traceability	Full (CoC per batch)	Factory-dependent	Minimal	Full (CoC per batch)
Dynamic flex	Not recommended	Not recommended	Not recommended	Recommended

The DuPont brand premium for LF9110E over generic acrylic ED flex laminates is justified by the IPC-4204/1 certification, full lot traceability backed by ISO 9001:2015 QMS, and the consistency of acrylic adhesive formulation that underpins the peel strength and dimensional stability specifications. Generic acrylic flex laminates may meet the headline numbers on a single-lot test, but lot-to-lot consistency is where the DuPont material’s quality system advantage translates into production yield.

Sourcing DuPont Pyralux LF9110E

Like LF9110R, the LF9110E construction is a broadly available, standard-stock product in DuPont’s Pyralux LF family. Pyralux LF Copper-Clad Laminate is supplied in sheet form, with standard dimensions of 24×36 in (610×914 mm), 24×18 in (610×457 mm), and 12×18 in (305×457 mm). There is a minimum of four sheets and a maximum of 25 sheets per pack. Lead times from authorised distributors are typically 1–3 weeks for standard quantities.

When ordering, it is essential to specify the correct suffix. Purchasing LF9110R when LF9110E is specified — or vice versa — results in a material substitution that changes copper grain structure, fine-pitch etch behaviour, and dynamic flex life without changing any of the headline dimensional or electrical specifications on the Certificate of Conformance. The CoC for both variants will show the same Dk, Df, and peel strength values. Only the copper foil type entry distinguishes them.

DuPont PCB materials cover the full Pyralux architecture — LF, AP, FR, and specialty constructions — and understanding the R / E / D suffix system is foundational knowledge for anyone specifying flex laminates across multiple product families.

Useful Resources for LF9110E Flex Circuit Designers

Resource	Description	URL
DuPont Pyralux LF Official Datasheet (PDF)	Full TDS for LF9110 with confirmed specs for both E and R variants	https://insulectro.com/wp-content/uploads/2021/09/EI-10117-Pyralux-LF-CCL-Data-Sheet.pdf
DuPont Pyralux LF — Elco PCB (PDF)	Alternative datasheet source with full construction table	https://www.elcopcb.com/wp-content/uploads/2024/04/PyraluxLFclad_DataSheet.pdf
DuPont Pyralux LF Official Product Page	Full Pyralux LF product family overview	https://www.dupont.com/electronics-industrial/pyralux-lf.html
DuPont Pyralux Product Selector	Identify correct LF product codes for custom constructions	https://pyralux.dupont.com
Cirexx Pyralux LF Datasheet (PDF)	Legacy DuPont LF datasheet with full R/E/D suffix explanation	https://www.cirexx.com/wp-content/uploads/LFclad_H-73244.pdf
DuPont Pyralux AP Datasheet (for comparison)	AP adhesiveless series specs for LF vs. AP evaluation	https://insulectro.com/wp-content/uploads/2021/09/EI-10124-Pyralux-AP-Data-Sheet.pdf
IPC-4204/1 Specification	Qualification standard for acrylic adhesive flex laminates	https://www.ipc.org
IPC-2223 Flexible PCB Design Standard	Bend radius rules and DFM guidelines	https://www.ipc.org
IPC-6013 Flex PCB Performance Standard	Acceptance and qualification testing for flex circuits	https://www.ipc.org
IPC-TM-650 Test Method Database	All test methods cited in LF9110E datasheets	https://www.ipc.org/TM

Frequently Asked Questions About DuPont Pyralux LF9110E

1. What is the exact construction of LF9110E and how does it differ from LF9110R?

DuPont Pyralux LF9110E is a single-sided, acrylic adhesive-based flex laminate with the following confirmed construction: 35 µm (1 oz/ft²) electro-deposited (ED) copper / 25 µm (1 mil) C-staged modified acrylic adhesive / 25 µm (1 mil) DuPont Kapton polyimide film. Total core thickness before coverlay is approximately 85 µm. LF9110R is identical in every physical dimension — same copper weight, adhesive thickness, and Kapton thickness — with the sole difference being the copper foil type: rolled-annealed (RA) in LF9110R versus electro-deposited (ED) in LF9110E. All dielectric, adhesion, and laminate-level properties (Dk, Df, peel strength, dimensional stability, solder float, certifications) are confirmed to be identical between the two variants.

2. Can LF9110E be used in dynamic flex applications — circuits that bend repeatedly during use?

No. LF9110E should not be specified for dynamic flex applications. ED copper’s columnar grain structure, while advantageous for fine-pitch etching, is fundamentally less resistant to cyclic bending fatigue than RA copper’s laminar grain structure. The crack initiation and propagation mechanism under repeated bending is more aggressive in ED copper at standard flex PCB operating conditions. For any application where the flex circuit bends more than a few hundred times during its service life — hinge interconnects, scan head cables, robotic arm flex, wearable body motion flex — specify LF9110R (RA copper) or LF9110D (double-treated RA copper). LF9110E is the correct choice only for static or bend-once-during-installation flex designs.

3. Why would an engineer specify LF9110E instead of LF9110R on a design?

There are two practical scenarios where LF9110E is the preferred specification over LF9110R. First, when the design includes trace widths at or below 3 mil (75 µm) and fine-pitch etch resolution is a production yield concern — ED copper’s columnar grain structure produces more consistent trace sidewalls at sub-75 µm dimensions than RA copper in a standard subtractive etch process. Second, when the manufacturing line uses a process that benefits from ED copper’s surface characteristics for resist lamination, without the surface preparation step that some RA copper requires before dry film or liquid resist application. Outside these two scenarios, LF9110R is generally the more versatile default choice because it supports both static and dynamic flex applications.

4. Are the electrical and dimensional specs on the Certificate of Conformance the same for LF9110E and LF9110R?

Yes — all laminate-level specifications on the Certificate of Conformance are identical for LF9110E and LF9110R. Dk (3.6 at 1 MHz, 3.0 at 10 GHz), Df (0.02 at both frequencies), peel strength (1.8 N/mm after lamination, 1.6 N/mm after solder), dimensional stability (±0.10% MD/TD), solder float pass at 288°C — these properties are determined by the Kapton film and acrylic adhesive system, not the copper foil type, and they are identical across the R, E, and D copper variants of the same LF construction. The only field on the CoC that distinguishes LF9110E from LF9110R is the copper foil type designation. This is why it is critical to specify the correct product code suffix when ordering — the headline specs on the datasheet do not alert a receiving inspector to a wrong-variant delivery.

5. What is LF9110D and when should it be specified instead of LF9110E or LF9110R?

LF9110D specifies double-treated rolled-annealed copper — RA copper foil with a layer of electro-deposited copper nodules applied to both surfaces of the foil. This double-treatment serves one specific purpose: it eliminates the mechanical surface preparation step (brushing, chemical roughening, or oxide treatment) that some fabricators apply to standard RA copper before laminating dry film resist or coverlay adhesive. The double-treated surface provides improved resist adhesion without requiring a surface prep operation, which reduces cycle time and process cost in high-throughput production environments. LF9110D retains RA copper’s laminar grain structure beneath the nodule layer, so it maintains the dynamic flex fatigue life advantages of LF9110R while adding the surface adhesion improvement. It is the correct specification when both dynamic flex capability and improved resist adhesion without surface preparation are required simultaneously.

Summary

DuPont Pyralux LF9110E is the electro-deposited copper variant of DuPont’s most widely used single-sided acrylic flex laminate construction: 35 µm (1 oz/ft²) ED copper / 25 µm acrylic adhesive / 25 µm DuPont Kapton polyimide, totalling approximately 85 µm before coverlay. Every dielectric, adhesion, and laminate-level property is identical to LF9110R. The copper foil type change — from RA to ED — delivers improved fine-pitch etch consistency at sub-75 µm trace dimensions and simplifies surface preparation for resist lamination in some production environments, at the cost of dynamic flex fatigue life that makes it unsuitable for any application involving repeated bending. Specified correctly for static flex applications requiring fine-pitch resolution, and avoided where dynamic flex is a design requirement, LF9110E is a well-characterised, IPC-4204/1-certified, ISO 9001:2015-quality-system-backed laminate with a 35-year track record in the flex circuit industry.