DuPont Pyralux LF7092R: 1 oz Cu / 0.5 mil Adhesive / 2 mil PI Flex Material Guide

If you’ve been sourcing single-sided copper-clad laminates for flex or rigid-flex builds, you’ve probably landed on DuPont Pyralux LF7092R at some point. It’s one of those SKUs that threads a specific needle — a 2 mil Kapton core with a thin 0.5 mil acrylic adhesive layer and 1 oz rolled-annealed copper on top. Not the thinnest stack in the LF family, and not the thickest either. For a lot of mid-range flex applications, it hits just right. This guide breaks down everything you need to know from a fabrication and design standpoint.

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What Is DuPont Pyralux LF7092R?

DuPont Pyralux LF7092R is a single-sided, acrylic-based copper-clad laminate (CCL) from DuPont’s Pyralux LF product family. It belongs to one of the most widely used flex laminate lines in the industry — the LF series has been the go-to for high-reliability flexible circuitry for over 35 years.

Decoding the product code tells you the whole story:

• LF — Pyralux LF series (acrylic adhesive-based, Kapton polyimide substrate)
• 70 — 0.5 mil (13 µm) acrylic adhesive thickness
• 9 — indicates 2 mil (51 µm) Kapton polyimide film
• 2 — single-sided construction with copper on one face
• R — rolled-annealed (RA) copper foil

The “R” suffix matters. Rolled-annealed copper is mechanically superior for dynamic flex applications because the grain structure runs parallel to the film, giving it far better flex-cycle endurance compared to electro-deposited (ED) copper.

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DuPont Pyralux LF7092R Construction Breakdown

Understanding the stackup is the first thing any PCB engineer should do before committing to a material. Here’s the layer-by-layer breakdown:

Layer	Specification	Metric Equivalent
Copper Foil	1 oz/ft² (RA)	35 µm
Acrylic Adhesive	0.5 mil	13 µm
Kapton® Polyimide Film	2.0 mil	51 µm
Total Nominal Thickness	~2.9 mil	~74 µm

The 2 mil Kapton core makes LF7092R noticeably more rigid than the 0.5 mil or 1 mil PI variants in the LF range, but still quite capable of tight bend radii when properly designed. The 0.5 mil adhesive keeps the overall stack lean while providing reliable bonding between the copper foil and the polyimide substrate.

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Technical Specifications

The table below summarizes the key electrical, mechanical, and thermal properties for the Pyralux LF CCL series, based on DuPont’s published typical values (using LF9110R as reference, applicable across the LF family at similar constructions):

Property	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
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
Dimensional Stability (MD/TD)	± 0.10%	IPC-TM-650 2.2.4
Solder Float, 288°C / 10 sec	Pass	IPC-TM-650 2.4.13
Volume Resistivity	> 10¹⁵ Ω·cm	IPC-TM-650 2.5.17
Surface Resistance	> 10¹⁴ Ω	IPC-TM-650 2.5.17
IPC Certification	IPC-4204/1	—
Copper Type	Rolled-Annealed (RA)	—
Operating Temp (Continuous)	≤ 125°C	—
Lamination Temp	182–199°C (360–390°F)	—
Lamination Pressure	14–28 kg/cm² (200–400 psi)	—
Lamination Time	1–2 hours at temperature	—

Engineer’s note: That 288°C solder float pass is a survival test, not a green light for sustained exposure at that temperature. With the acrylic adhesive in the LF family having a Tg in the 70–100°C range, continuous operation above 125°C is off the table. If your application runs hot, look at Pyralux AP instead.

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Key Features and Benefits of DuPont Pyralux LF7092R

High Bond Strength for Long-Term Reliability

The proprietary C-staged modified acrylic adhesive used in Pyralux LF7092R delivers peel strength values that exceed the IPC minimums — 1.8 N/mm after lamination drops to 1.6 N/mm post-solder, which still gives you solid adhesion margins for most demanding applications.

Rolled-Annealed Copper for Superior Flex Endurance

For applications with repeated bending cycles, RA copper is non-negotiable. The grain structure in RA foil runs parallel to the film surface, which means it handles fatigue far better than ED copper in dynamic flex scenarios. For static flex or rigid-flex applications, both work fine, but if your design bends repeatedly in service, the “R” suffix in LF7092R is exactly what you want.

No Refrigerated Storage Required

Unlike some B-staged adhesive systems, Pyralux LF materials don’t need cold chain handling. Store sheets at 4–29°C (40–85°F) below 70% relative humidity, and you’re covered for a two-year warranty window from shipment date. That simplifies logistics compared to epoxy prepregs significantly.

NASA Low-Outgassing Data Available

For space and aerospace applications, outgassing is a serious concern — trapped volatiles in a vacuum environment can contaminate optics or degrade neighboring components. DuPont has NASA CVCM/TML data available for the LF series, which makes compliance certification much smoother.

Halogen-Free and RoHS Compliant

LF7092R meets RoHS requirements and is halogen-free, important for designs targeting EU markets or customers with green procurement policies.

Multiple Lamination Cycles Tolerated

The material can withstand multiple lamination cycles without delamination or property degradation — useful when you’re building multilayer rigid-flex stacks where you might laminate in stages.

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Where DuPont Pyralux LF7092R Gets Used

The 2 mil PI / 0.5 mil adhesive / 1 oz Cu stack of LF7092R puts it squarely in the mid-weight flex laminate category. Here’s where you typically see it:

Application Segment	Why LF7092R Fits
Consumer electronics	Compact, low-profile flex interconnects in phones, tablets
Wearables	Thin enough for body-conforming designs, RA Cu handles fatigue
Medical devices	Reliable flex in hearing aids, surgical tools, imaging systems
Aerospace / Avionics	NASA low-outgassing data, polyimide thermal stability
Military electronics	Proven reliability, IPC-4204/1 certification
Automotive displays	Withstands automotive thermal cycling and vibration
Rigid-flex PCBs	Excellent compatibility as the flex layer in multilayer stacks

The 2 mil Kapton provides a stiffer flex platform than the 1 mil variants, which some designers actually prefer for handling and dimensional stability during fabrication — it’s less prone to wrinkling in processing.

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Pyralux LF7092R vs. Other LF Variants: How It Compares

Choosing between LF variants is often about dialing in the right total thickness and flexibility. Here’s a quick comparative table for single-sided LF constructions:

Product Code	Cu (oz)	Adhesive (mil)	Kapton (mil)	Total (approx.)	Best For
LF7002R	1 oz	0.5	0.5	~1.4 mil	Ultra-thin, tight bend radius
LF7062R	0.5 oz	0.5	1.0	~1.7 mil	Thin dynamic flex, fine traces
LF7092R	1 oz	0.5	2.0	~2.9 mil	Mid-weight flex, rigid-flex inner layers
LF9110R	1 oz	1.0	1.0	~2.4 mil	General purpose single-sided
LF9120R	1 oz	1.0	2.0	~3.4 mil	Stiffer, thicker dielectric builds
LF9150R	1 oz	1.0	5.0	~6.4 mil	High dielectric thickness, RF structures

The LF7092R occupies a useful middle ground — thicker Kapton than LF7002R or LF7062R for better dimensional control and handling, while the 0.5 mil adhesive keeps the overall build thinner than the 1 mil adhesive counterparts at the same PI thickness.

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Processing Guidelines for DuPont Pyralux LF7092R

Lamination Parameters

Getting lamination right is critical with acrylic-adhesive laminates. The standard Pyralux LF lamination window is:

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

Work within this window and you’ll get full C-staging of the acrylic adhesive. Undercuring results in poor peel strength; overcuring at the high end can start degrading the adhesive.

Drilling and Routing

Standard carbide drill bits work fine for through-holes. Maintain adequate vacuum around drill heads — while the material itself poses low handling risk, good ventilation practice applies for any polyimide drilling operation.

Chemical Processing Compatibility

Pyralux LF materials are fully compatible with standard flex PCB wet chemistry processes. This includes:

• Oxide treatment (black/brown/alternative)
• Electroless copper / electrolytic copper plating
• Photoresist lamination and imaging
• Wet etching (ferric chloride, cupric chloride, alkaline)
• Soldermask application (liquid photoimageable)
• ENIG, HASL, and immersion tin surface finishes

Coverlay and Soldermask

For encapsulation, Pyralux LF Coverlay (acrylic-based, also from the LF family) is the natural pairing for LF7092R and ensures adhesive compatibility. LPI soldermask is also well-supported, though many flex designers prefer coverlay for dynamic flex zones due to its better flex-cycle performance.

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Storage and Handling

Condition	Requirement
Storage Temperature	4–29°C (40–85°F)
Relative Humidity	Below 70% RH
Freezing	Not permitted
Warranty Period	2 years from shipment date
Sheet Sizes Available	24×36 in, 24×18 in, 12×18 in
Sheets Per Pack	Min 4 / Max 25

Always store in original DuPont packaging and keep the roll labels — they carry lot numbers, IPC spec references, and DuPont order numbers needed for traceability if a quality inquiry comes up later.

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DuPont Pyralux LF7092R: Useful Resources

The following technical documents and databases are the primary references any engineer should have bookmarked when working with this material:

Resource	Type	Access
DuPont Pyralux LF CCL Official Datasheet (EI-10117)	Official PDF Datasheet	Free
Pyralux Product Selector Tool	Interactive Selection Database	Free
DuPont Pyralux LF Product Page	Product Overview & Portfolio	Free
IPC-4204/1 Standard (Flexible Metal Clad Laminates)	Industry Standard	Paid via IPC
IPC-TM-650 Test Methods	Test Methods Manual	Free via IPC
DuPont PCB Materials Overview	Practical Engineering Reference	Free
Pyralux Safe Handling Guide	Safety Documentation	Free
NASA Low-Outgassing Data (GSFC)	NASA Materials Database	Free

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Frequently Asked Questions About DuPont Pyralux LF7092R

1. What is the difference between Pyralux LF7092R and Pyralux AP in terms of construction?

Pyralux LF7092R is a three-layer construction — copper foil bonded to Kapton polyimide through an acrylic adhesive. Pyralux AP is an adhesiveless (two-layer) construction where copper is deposited directly onto the polyimide. The AP series offers higher continuous operating temperatures (up to 200°C+), better dimensional stability, and thinner overall profiles, but costs more. LF7092R with its acrylic adhesive is the cost-effective workhorse for the majority of commercial and mil-spec flex applications operating below 125°C.

2. Can DuPont Pyralux LF7092R be used for dynamic flex applications?

Yes, with caveats. The rolled-annealed copper (“R” suffix) is specifically chosen for dynamic flex endurance. However, the minimum bend radius must be respected — with 1 oz copper and 2 mil PI, design your flex zones to a minimum bend radius of roughly 6–10× the total material thickness. For very high cycle-count applications, consult DuPont’s flex life data or run IPC-TM-650 2.4.3 flex endurance testing on a representative coupon before committing to production.

3. Does DuPont Pyralux LF7092R require refrigerated storage?

No. Unlike some prepregs and B-staged epoxy systems, Pyralux LF CCL requires no refrigeration. Standard storage at 4–29°C and below 70% relative humidity is sufficient for a two-year shelf life. This is one of the practical advantages of the LF acrylic adhesive system over alternative adhesive chemistries used by some competitors.

4. What coverlay is compatible with DuPont Pyralux LF7092R?

The recommended coverlay is from DuPont’s own Pyralux LF Coverlay series, which uses the same acrylic adhesive chemistry as the base laminate. This ensures adhesive-to-adhesive compatibility and consistent lamination parameters. For the 2 mil PI core of LF7092R, pairing with an LF coverlay using 0.5 mil or 1.0 mil acrylic adhesive on 1 mil PI is common for balanced constructions.

5. How does the 0.5 mil adhesive in LF7092R compare to the 1.0 mil adhesive in LF9120R?

The 0.5 mil adhesive in LF7092R results in a thinner overall laminate stack (~2.9 mil total vs. ~3.4 mil for LF9120R with the same PI thickness). Thinner adhesive generally improves flex performance and lowers z-axis CTE contribution. The trade-off is marginally lower initial peel strength compared to the 1 mil adhesive constructions, though both comfortably exceed IPC minimum requirements. For most flex designs, the choice between 0.5 and 1 mil adhesive comes down to total thickness targets rather than strength concerns.