DuPont Pyralux LF9110R: Engineer’s Complete Datasheet Guide to 1 oz RA Cu / 1 mil PI Acrylic Flex Laminate

Every experienced flex circuit designer knows the Pyralux LF series. It is not the newest product in DuPont’s flex laminate portfolio, and it is not the highest-performance material in the catalogue — those distinctions belong to the adhesiveless AP series. But DuPont Pyralux LF9110R remains one of the most widely specified, broadly available, and cost-effectively manufactured single-sided flex laminate constructions in the world. The combination of 1 oz (35 µm) rolled-annealed copper, 1 mil (25 µm) C-staged modified acrylic adhesive, and 1 mil (25 µm) Kapton polyimide film is the foundation of an enormous proportion of the world’s consumer electronics FPCs, industrial flex interconnects, and medical device flex assemblies.

Understanding what this construction actually delivers — its confirmed specification data, where it sits versus the AP series, when it is the right call, and when it is not — is the working knowledge every flex circuit engineer needs. This guide covers all of it.

Decoding the DuPont Pyralux LF9110R Part Number

The Pyralux LF naming system encodes the construction at every segment. LF9110R breaks down as follows:

Code Segment	What It Encodes	LF9110R 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	Dielectric (Kapton) thickness designator	1 mil (25 µm) Kapton polyimide
0	Layer structure designator	Single-sided clad
R	Copper foil type	Rolled-Annealed (RA) copper

The “0” in the fifth position is the single-sided indicator — distinguishing LF9110R from LF9111R, which carries the same copper and adhesive weights but is double-sided clad. The “R” suffix distinguishes RA copper from “E” (electro-deposited) and “D” (double-treated) variants. For the standard single-sided flex market where LF9110R lives, RA copper is the default specification for its superior flex endurance and peel strength characteristics.

What Makes LF9110R a Three-Layer Construction — And Why It Matters

This is the single most important structural distinction between the Pyralux LF series and the Pyralux AP series, and it directly affects the electrical performance numbers in the datasheet. LF9110R is a three-layer laminate: copper foil bonded to Kapton polyimide film through an acrylic adhesive intermediate. The AP series is a two-layer adhesiveless laminate: copper bonded directly to polyimide with no adhesive layer.

That acrylic adhesive layer in the LF9110R is why its dielectric properties — particularly loss tangent — are measurably different from the AP series. The adhesive has its own dielectric characteristics that contribute to the overall electrical performance of the laminate. This is not a flaw; it is a known material characteristic that engineers account for in design.

LF9110R Three-Layer Stack Dimensions

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

For comparison, the adhesiveless AP9111R (1 oz / 1 mil PI, no adhesive) produces a total two-sided core of approximately 95 µm — marginally thicker than LF9110R’s single-sided 85 µm stack because it carries two copper faces.

DuPont Pyralux LF9110R Full Technical Specifications

The following tables represent the confirmed published specification data from DuPont’s official Pyralux LF datasheet. All values are for the LF9110R construction specifically.

Electrical Properties

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	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 (acrylic adhesive flex laminate spec)
RoHS	Compliant
ISO 9001:2015	Manufactured under certified QMS
Certificate of Conformance	Available with every batch
UL 94 V-0	Per DuPont standard

Note: LF9110R is certified to IPC-4204/1 — the standard for acrylic adhesive-based flexible copper-clad laminates — rather than IPC-4204/11, which is the adhesiveless specification that governs the AP series. This distinction matters when writing specification notes in engineering documentation.

The Critical Difference: LF9110R Electrical Performance vs. AP Series

The most important electrical difference between the Pyralux LF acrylic series and the Pyralux AP adhesiveless series is not the dielectric constant — it is the loss tangent.

Property	LF9110R (Acrylic, 3-layer)	AP9111R (Adhesiveless, 2-layer)
Dk @ 1 MHz	3.6	3.4
Dk @ 10 GHz	3.0	3.2
Df @ 1 MHz	0.02	0.002
Df @ 10 GHz	0.02	0.003
Peel strength (as lam.)	1.8 N/mm	>1.8 N/mm
Peel strength (after solder)	1.6 N/mm	>1.8 N/mm
Total construction	3-layer (Cu/Adhesive/PI)	2-layer (Cu/PI)
IPC specification	IPC-4204/1	IPC-4204/11

The Df of 0.02 in the LF9110R is 10× higher than the AP series at low frequency and nearly 7× higher at 10 GHz. This is not a rounding difference — it is a fundamental consequence of the acrylic adhesive layer’s higher dielectric loss compared to the pure polyimide dielectric in the AP construction. For designs operating at frequencies below 500 MHz where signal loss is not a primary concern, this difference is largely academic. For RF flex circuits, controlled impedance designs above 1 GHz, or any application where insertion loss in the flex section appears in the signal integrity budget, the LF9110R’s 10× higher Df is a design-limiting factor.

When LF9110R Is the Right Material

Being clear about what LF9110R is optimised for is more useful than listing everything it falls short of. This is the correct choice when:

The design requires a cost-effective, broadly available single-sided flex laminate for standard-frequency signal interconnects below ~500 MHz. The LF series is the workhorse of the flex circuit industry precisely because its cost is significantly lower than the adhesiveless AP series — a material cost difference that translates meaningfully in high-volume consumer electronics production.

The application calls for static or low-cycle flex, not dynamic bending. The RA copper provides good flex fatigue resistance, but the acrylic adhesive layer limits the flex endurance compared to an adhesiveless construction of equivalent dimensions — the adhesive bondline is the mechanical weak point under repeated cyclic bending.

The fabricator is processing multilayer constructions where LF laminates function as bond plies or inner-layer cores in a rigid-flex stackup alongside FR4 rigid sections. The Pyralux LF family is explicitly designed for use in multilayer constructions, and the acrylic adhesive system is well-characterised across industry for this application.

The thermal processing temperature stays well within the adhesive’s working range. The acrylic adhesive has a lower Tg than pure polyimide — approximately 100–130°C for the cured acrylic versus 220°C for the AP’s all-polyimide construction — making the LF9110R the wrong choice for applications sustaining temperatures above ~120–130°C continuously.

DuPont Pyralux LF9110R in the Full LF Family

Understanding where LF9110R fits in the full LF product range helps designers quickly identify adjacent constructions when thicker Kapton, heavier copper, or double-sided copper is needed.

Standard LF Single-Sided Clad Offerings

Product Code	Cu (oz / µm)	Adhesive (mil / µm)	Kapton (mil / µm)	Total Core
LF7012R	0.5 oz / 18 µm	0.5 mil / 13 µm	0.5 mil / 13 µm	~44 µm
LF7062R	0.5 oz / 18 µm	0.5 mil / 13 µm	1.0 mil / 25 µm	~56 µm
LF7002R	1 oz / 35 µm	0.5 mil / 13 µm	0.5 mil / 13 µm	~61 µm
LF9110R	1 oz / 35 µm	1 mil / 25 µm	1 mil / 25 µm	~85 µm
LF9120R	1 oz / 35 µm	1 mil / 25 µm	2 mil / 51 µm	~111 µm
LF9150R	1 oz / 35 µm	1 mil / 25 µm	5 mil / 127 µm	~197 µm
LF9210R	2 oz / 70 µm	1 mil / 25 µm	1 mil / 25 µm	~120 µm
LF9220R	2 oz / 70 µm	1 mil / 25 µm	2 mil / 51 µm	~146 µm

Standard LF Double-Sided Clad Offerings (for reference)

Product Code	Cu (oz / µm) each side	Adhesive (mil / µm)	Kapton (mil / µm)
LF9111R	1 oz / 35 µm	1 mil / 25 µm	1 mil / 25 µm
LF9121R	1 oz / 35 µm	1 mil / 25 µm	2 mil / 51 µm
LF9151R	1 oz / 35 µm	1 mil / 25 µm	5 mil / 127 µm
LF9212R	2 oz / 70 µm	1 mil / 25 µm	1 mil / 25 µm

LF9110R is the single-sided anchor of the 1 oz / 1 mil adhesive / 1 mil Kapton configuration. Its double-sided equivalent, LF9111R, carries the same material weights with copper on both faces of the same 1 mil adhesive / 1 mil Kapton core.

Real-World Applications for DuPont Pyralux LF9110R

The LF9110R appears in a wide range of consumer, industrial, and medical electronics applications where cost-effectiveness, supply chain depth, and standard fabrication process compatibility outweigh the need for low loss tangent or extreme thermal stability.

Consumer Electronics FPCs and Ribbon Cables

The vast majority of single-sided flex circuits in consumer electronics — smartphone antenna flex, display backlight drive cables, trackpad interconnects, keyboard ribbon cables — are built on acrylic adhesive flex laminates in the Pyralux LF family or equivalent. LF9110R’s 1 oz / 1 mil / 1 mil construction is the baseline specification that most flex circuit commodity manufacturers offer as their standard material. At production volumes, the cost advantage over adhesiveless AP constructions is significant and commercially decisive for cost-sensitive consumer electronics programs.

Multilayer Rigid-Flex Constructions as Flex Core Layer

Pyralux LF laminates are explicitly recommended for use in producing high reliability, high density circuitry in flexible, rigid-flex, and all-flexible multilayer constructions. In a rigid-flex stackup where the flex zone carries low-frequency signals and the signal integrity budget does not require low-loss dielectrics, LF9110R is a cost-effective inner flex core layer. Its acrylic adhesive system is well-understood by rigid-flex fabricators and is compatible with the Pyralux LF bond ply materials used to build up multilayer constructions.

Industrial Sensor and Control Interconnects

Flex circuits used in industrial sensors, HVAC controls, automotive interior lighting, and machinery control panels operate at frequencies well below 500 MHz where the LF9110R’s Df of 0.02 has no practical impact on signal quality. The material’s 288°C solder float pass and IPC-4204/1 qualification make it appropriate for standard lead-free assembly processes, and its broad distribution network ensures supply chain continuity for programs that need multi-source material availability.

Medical Diagnostic and Monitoring Devices (Non-Implant)

External medical devices — patient monitoring leads, diagnostic probe flex assemblies, portable diagnostic instrument interconnects — regularly use LF9110R-equivalent constructions where the flex circuit carries low-frequency biopotential signals or instrument control signals without high-frequency signal integrity requirements. DuPont’s standard caution applies: Pyralux LF is not approved for permanent human implantation.

Automotive Interior Electronics and Instrument Clusters

Flex circuits routing signals between instrument cluster displays, button arrays, and control modules in automotive interiors operate within temperature ranges that the LF9110R’s acrylic adhesive system tolerates — typically −40°C to +85°C for interior applications. The 1 oz copper provides adequate current capacity for the LED drive currents and low-power logic signals typical in instrument cluster flex circuits.

Fabrication and Design Considerations for LF9110R

Bend Radius: LF9110R Single-Sided Construction

Total finished circuit thickness for LF9110R with a standard 25 µm polyimide film coverlay (including coverlay adhesive):

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

Applying IPC-2223 guidelines:

Flex Type	Multiplier	LF9110R Min. Bend Radius
Static (bend-to-install)	6× total thickness	~0.8 mm
Dynamic (repeated flex)	10× total thickness	~1.4 mm
High-cycle dynamic (>10k cycles)	15× total thickness	~2.0 mm

The single-sided construction has a mechanical advantage in bending — with copper on only one face, the laminate bends more easily toward the coverlay side (copper in tension) than away from it. Always orient single-sided flex circuits in bend zones so the copper layer is on the outside of the bend (tension side), which is the lower-stress configuration for the copper conductor.

Trace Width and Current Capacity at 1 oz Copper

Standard current capacity guidance for 1 oz (35 µm) external copper traces on LF9110R:

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

Lamination: Acrylic Adhesive B-Stage Considerations

The acrylic adhesive in LF9110R is C-staged (fully crosslinked) as supplied — it does not require a separate B-stage cure step during initial processing. However, when LF9110R is used as a flex core layer in a multilayer lamination with additional bondplies, the lamination conditions (182–199°C, 14–28 kg/cm², 1–2 hours) must be applied correctly. The B-staged acrylic adhesive bondply materials (LF and FR series) used in combination with LF9110R undergo their full cure during the multilayer lamination press cycle — these contain trace unreacted monomers prior to cure and require adequate ventilation during press cycles.

Moisture Bake-Out Before Assembly

As with all polyimide-based flex laminates, moisture absorbed by the Kapton film during storage can cause blistering during reflow soldering. Bake LF9110R assemblies at 120°C for a minimum of 4 hours before lead-free reflow, and process within 8 hours. This is especially important in humid environments or where material has been stored for extended periods outside of original packaging.

Storage Requirements

Store LF9110R in original DuPont packaging at 4–29°C (40–85°F) and below 70% relative humidity. Do not freeze. The product has a two-year warranty from the date of shipment when stored within these conditions. DuPont provides a Certificate of Conformance with every batch, and roll labels carry the lot number, order numbers, IPC specification, and customer part number — retain these labels for traceability.

LF9110R vs. Key Competing Materials

Parameter	LF9110R (DuPont)	AP9111R (DuPont)	Shengyi SHE-FLEX LF	Generic Acrylic PI Flex
Construction	3-layer (Cu/Acrylic/PI)	2-layer (Cu/PI)	3-layer	3-layer
Cu Weight	1 oz / 35 µm RA	1 oz / 35 µm RA	1 oz / 35 µm	1 oz / 35 µm
Adhesive	1 mil acrylic	None	Acrylic	Acrylic
Kapton	1 mil / 25 µm	1 mil / 25 µm	~25 µm	~25 µm
Dk @ 1 MHz	3.6	3.4	~3.5–3.7	~3.5–4.0
Df @ 1 MHz	0.02	0.002	~0.02–0.03	~0.02–0.04
Adhesive Tg	~100–130°C	N/A (none)	~100–120°C	~80–120°C
IPC certification	IPC-4204/1	IPC-4204/11	Varies	Varies
ISO 9001:2015	Full DuPont QMS	Full DuPont QMS	Factory-dependent	Factory-dependent
Relative cost	Lower	Higher	Lower	Lowest
Best fit	Standard FPC, multilayer	High-reliability, RF flex	Commodity FPC	Low-cost commodity

The comparison against AP9111R is the one designers face most often. If signal frequencies exceed 500 MHz, temperature exposure exceeds 130°C continuously, or the application requires IPC-4204/11 certification (mandatory for some aerospace and medical programs), the AP series is the correct specification. For the large majority of commercial flex applications below these thresholds, LF9110R’s combination of lower cost, broad availability, and fully characterised fabrication process is the practical choice.

Sourcing DuPont Pyralux LF9110R

Unlike the ultra-thin AP7-series constructions, LF9110R is a standard, broadly stocked product in the Pyralux LF family. DuPont supplies it in standard sheet dimensions of 24×36 in, 24×18 in, and 12×18 in (4–25 sheets per pack). Lead times from authorised distributors are typically 1–3 weeks for standard quantities, with production lot pricing available for high-volume programs.

DuPont PCB materials span the full Pyralux product architecture — LF, FR, AP, and specialty constructions. Understanding the relationship between these product families helps procurement teams make the correct material specification for each design tier in a product portfolio, rather than defaulting to a single material across all designs regardless of performance requirements.

Useful Resources for LF9110R Flex Circuit Designers

Resource	Description	URL
DuPont Pyralux LF Official Datasheet (PDF)	Full TDS for LF9110R with confirmed specifications	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 Official Product Page	Full Pyralux portfolio overview and sample requests	https://www.dupont.com/electronics-industrial/pyralux.html
DuPont Pyralux Laminate Product Selector	Product code identification for custom constructions	https://pyralux.dupont.com
DuPont Pyralux AP Datasheet (comparison reference)	Full TDS for AP adhesiveless series	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 and DFM design rules	https://www.ipc.org
IPC-6013 Flex PCB Performance Standard	Acceptance and qualification testing	https://www.ipc.org
Epectec Flex PCB Material Overview	Practical material selection guide covering LF vs AP tradeoffs	https://www.epectec.com/flex/
IPC-TM-650 Test Method Database	All test methods cited in LF9110R datasheet	https://www.ipc.org/TM

Frequently Asked Questions About DuPont Pyralux LF9110R

1. What is the exact confirmed construction of LF9110R and is it single-sided or double-sided?

DuPont Pyralux LF9110R is a single-sided copper-clad laminate. The confirmed construction from DuPont’s official datasheet is: 35 µm (1 oz/ft²) rolled-annealed 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. The double-sided equivalent — copper on both faces of the same 1 mil adhesive / 1 mil Kapton construction — is LF9111R. Many engineers searching “LF9110R” are evaluating single-sided flex for FPC and multilayer rigid-flex applications; the “0” in the product code’s fifth position is the single-sided designator.

2. Why is the loss tangent of LF9110R (0.02) so much higher than the AP series (0.002)?

The higher loss tangent of LF9110R directly results from the acrylic adhesive layer in its three-layer construction. The C-staged modified acrylic adhesive has inherently higher dielectric loss than DuPont Kapton polyimide film — approximately 10× higher at low frequency and 7× higher at 10 GHz. Since the signal field from a trace on LF9110R passes through both the Kapton layer and the acrylic adhesive layer, the combined electrical performance reflects contributions from both materials. The AP series eliminates the adhesive entirely, so the signal field passes through pure Kapton polyimide only — delivering the 10× lower loss tangent. For designs operating above 500 MHz to 1 GHz, this difference in Df becomes a meaningful contributor to signal attenuation in the flex section.

3. Can LF9110R withstand lead-free reflow soldering?

Yes. LF9110R passes DuPont’s solder float test at 288°C for 10 seconds, confirming that the laminate withstands the thermal exposure of standard lead-free reflow profiles (typical peak 255–260°C for SAC305 solder). The critical pre-assembly requirement is a moisture bake-out of at least 4 hours at 120°C before reflow, followed by assembly within 8 hours. Moisture absorbed by the Kapton polyimide layer during storage will cause blistering and delamination during reflow if the bake-out step is skipped — this is a consistent failure mode in acrylic-based flex laminates assembled without pre-bake. The acrylic adhesive’s cured Tg (~100–130°C) means the laminate should not be subjected to continuous operating temperatures above approximately 120°C; standard reflow (brief exposure to 260°C) is tolerated but not sustained operation at these temperatures.

4. What is the difference between LF9110R (single-sided) and LF9111R (double-sided) and when should each be specified?

LF9110R has copper on one face only; LF9111R has copper on both faces of the same 1 oz / 1 mil acrylic / 1 mil Kapton construction. LF9110R is the correct specification when: the design requires circuitry on only one face (single-sided FPC), when the back face of the laminate will serve as a bonding surface for coverlay only, or when the flex circuit will be laminated into a multilayer construction where the bare Kapton face bonds to a bondply or rigid prepreg. LF9111R is correct when: both faces carry active traces, pads, or ground planes requiring etching, imaging, and plating. The two products have identical electrical and mechanical property data — the distinction is entirely in how many copper faces the fabricator needs to process.

5. When should an engineer choose LF9110R instead of AP9111R for the same flex application?

The choice comes down to frequency, thermal requirements, and cost. Choose LF9110R when the flex circuit operates below ~500 MHz (where the 10× difference in Df has negligible impact on signal integrity), when operating temperature stays below ~120°C continuously, when the program does not require IPC-4204/11 certification (the adhesiveless laminate standard), and when material cost is a significant program constraint — which it typically is in high-volume consumer electronics. Choose AP9111R when: the design includes RF signals or high-speed digital interfaces above 500 MHz where insertion loss in the flex section matters; when operating temperatures exceed 120°C continuously; when the program requires IPC-4204/11 certification for aerospace, medical, or defense program compliance; or when the flex section undergoes sustained dynamic bending where the adhesiveless peel strength retention under thermal cycling is superior. In practice, the LF9110R serves the commercial and industrial mass market; the AP9111R serves the high-reliability and high-frequency niche.

Summary

DuPont Pyralux LF9110R is the industry’s baseline single-sided flex laminate: 1 oz (35 µm) rolled-annealed copper bonded to 1 mil (25 µm) DuPont Kapton polyimide film through a 1 mil (25 µm) C-staged modified acrylic adhesive, certified to IPC-4204/1 and manufactured under DuPont’s ISO 9001:2015 quality system. Its confirmed Df of 0.02 at both 1 MHz and 10 GHz reflects its three-layer acrylic construction — meaningful at RF frequencies but irrelevant for the vast majority of signal interconnect applications it is designed to serve. Broadly available, well-characterised, cost-effective, and supported by two years of DuPont warranty and full batch-level traceability, it is the correct specification for single-sided flex FPCs, multilayer rigid-flex inner core layers, and standard-frequency industrial and consumer electronics interconnects worldwide.