DuPont Pyralux LF7002R: 1 oz Cu / 0.5 mil PI Thin Substrate Flex Circuit Material — Complete Engineer’s Guide

There’s a specific gap in the flexible laminate catalog that most engineers only discover when a design is already locked: you need 1 oz copper for adequate current capacity, but you cannot afford the total stack height that a standard 1 mil Kapton construction delivers. That gap is exactly where DuPont Pyralux LF7002R lives. It pairs full 1 oz rolled-annealed copper with the thinnest available adhesive and Kapton film in the LF series — giving you usable current capacity in a substrate that’s still firmly in the ultra-thin territory. This article walks through every aspect of LF7002R that matters to a working PCB engineer: construction, specifications, design constraints, processing requirements, and where it fits against the alternatives you’re likely weighing at the same time.

What Is DuPont Pyralux LF7002R?

DuPont Pyralux LF7002R is a single-sided, acrylic-adhesive-based flexible copper-clad laminate (FCCL) from DuPont’s Pyralux LF product family. It is constructed from a 0.5 mil (13 µm) DuPont Kapton® polyimide film, bonded to a 1 oz/ft² (35 µm) rolled-annealed copper foil through a 0.5 mil (13 µm) C-staged modified acrylic adhesive.

The design intent is straightforward: take the thinnest available LF construction — the 0.5 mil adhesive / 0.5 mil Kapton combination of the LF7xxx sub-series — and pair it with 1 oz copper instead of the 0.5 oz foil used in LF7012R. The result is a material with meaningfully better current-carrying capability than LF7012R while retaining a total stack height that is still well below any LF9xxx construction. LF7002R carries 35 µm (1 oz) copper over a 13 µm (0.5 mil) adhesive and 13 µm (0.5 mil) Kapton core.

Decoding the LF7002R Part Number

DuPont’s Pyralux part code is systematic. Once you understand it, the full construction reads directly from the product number — which matters when you’re reviewing quotes or fab drawings at speed.

Code Segment	Value	Meaning
LF	—	Acrylic-based LF series, non-flame-retardant
7	—	LF7xxx sub-series: 0.5 mil (13 µm) thin adhesive system
0	—	1 oz/ft² copper weight indicator
0	—	Construction index within sub-series
2	—	0.5 mil (13 µm) Kapton® dielectric thickness
R	—	Rolled-Annealed (RA) copper foil

The LF7xxx designation is the important differentiator from the mainstream LF9xxx series. Any time you see LF7 at the start of a Pyralux part number, the adhesive is 0.5 mil rather than the 1 mil used in LF9xxx constructions. That 0.5 mil adhesive makes a real difference to total stack height and to coverlay lamination behavior, as covered later in the processing section.

Full Layer Stack and Physical Dimensions

Layer	Material	Metric Thickness	Imperial Thickness
Copper Foil	Rolled-annealed (RA) copper	35 µm	1 oz/ft²
Acrylic Adhesive	C-staged modified acrylic	13 µm	0.5 mil
Dielectric Core	DuPont Kapton® polyimide	13 µm	0.5 mil
Total (uncovered)		~61 µm	~2.4 mil

At approximately 2.4 mil (61 µm) total thickness before coverlay, LF7002R sits between the ultra-thin LF7012R (~1.7 mil) and the more common LF9110R (~3.4 mil). For context: the added thickness versus LF7012R is almost entirely the doubled copper weight — the adhesive and Kapton layers are identical between the two. Engineers who need to compare both constructions for a thickness-constrained design can isolate exactly how much that copper weight difference costs in stack height.

Electrical and Mechanical Properties

All values below are from DuPont’s current Pyralux LF datasheet (EI-10117, 2020 revision), tested to IPC Test Method TM-650. These are typical values for the LF series — actual performance can vary with construction and processing conditions.

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 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 for 10 s	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

One critical item engineers must note upfront: LF7002R is not certified to IPC-4204/1 in DuPont’s current standard catalog. This is consistent across the LF7xxx ultra-thin sub-series where the 0.5 mil adhesive / 0.5 mil Kapton combination falls outside the constructions that carry IPC-4204/1 certification. If your procurement contract, mil-spec, or medical device documentation requires IPC-4204/1 traceability, you will need LF7011R (1 oz / 0.5 mil adhesive / 1 mil Kapton — which IS certified) or step into the LF9xxx family. For commercial, consumer, and industrial applications where IPC certification is not contractually mandated, this is usually a non-issue.

How LF7002R Compares to Key Alternatives

This is the comparison engineers actually need when evaluating this part. The table below covers the most relevant neighboring constructions in the thin-flex space:

Product Code	Cu Weight	Adhesive	Kapton	Sides	Total Stack	IPC-4204	Key Differentiator
LF7002R	1 oz / 35 µm	0.5 mil	0.5 mil	Single	~2.4 mil	No	1 oz Cu, minimum dielectric
LF7012R	0.5 oz / 18 µm	0.5 mil	0.5 mil	Single	~1.7 mil	No	Thinnest possible build
LF7011R	1 oz / 35 µm	0.5 mil	1.0 mil	Single	~2.9 mil	Yes	IPC-certified, 1 oz Cu
LF9110R	1 oz / 35 µm	1.0 mil	1.0 mil	Single	~3.4 mil	Yes	Standard 1 oz thin flex
LF7010R	1 oz / 35 µm	0.5 mil	1.0 mil	Double	~3.9 mil	Yes	Double-sided equivalent
LF7004R	0.5 oz / 18 µm	1.0 mil	0.5 mil	Single	~2.2 mil	No	0.5 oz, thicker adhesive

The decision between LF7002R and LF7011R is the comparison that matters most in practice. Both have identical copper weight and adhesive thickness — the only structural difference is the Kapton core (0.5 mil vs. 1 mil). LF7011R’s thicker dielectric adds ~0.5 mil to the stack but buys you IPC-4204/1 certification and slightly better dimensional stability. If neither of those factors is a hard requirement for your project, LF7002R gives you the thinner, lighter construction.

Design Guidelines for DuPont Pyralux LF7002R

Bend Radius — The Real Numbers for 1 oz Copper at 0.5 mil Kapton

One of the practical advantages LF7002R carries over standard LF9110R is bend radius. Thinner total laminate = tighter achievable bend. The IPC-2223 standard for flexible PCB design provides guidance on minimum bend radii based on construction and application type.

For a single-layer RA copper flex in static service (bent once during installation and not moved again), engineers apply approximately 6× the total laminate thickness as a conservative minimum. At 61 µm total for LF7002R, that puts the theoretical static minimum at around 0.37 mm — substantially tighter than the ~0.20 mm achievable with LF7012R’s lighter copper, but still well within the range needed for most compact packaging applications.

For dynamic flex service with repeated bending cycles, the multiplier increases significantly. At 20× total thickness, dynamic minimum for LF7002R is approximately 1.22 mm. At 40× for high-cycle applications, it extends to 2.44 mm. The 1 oz RA copper handles bending fatigue considerably better than electro-deposited copper at the same weight — the elongated grain structure of RA copper is specifically what makes it the material of choice wherever flex fatigue matters. Always confirm radius with physical coupon testing for your specific design geometry before production release.

Trace Width, Spacing, and Current Capacity on 1 oz Copper

The step up to 1 oz copper compared to LF7012R’s 0.5 oz foil has direct, practical consequences for trace current capacity. As a rough reference using IPC-2221 external conductor guidelines, a 10 mil (0.25 mm) trace on 1 oz copper carries approximately 1.0–1.2 A for a 10°C temperature rise. At 0.5 oz, the same width carries roughly half that. For designs routing power alongside signals — battery management interconnects, sensor supply rails, LED driver bus traces — LF7002R’s 1 oz copper often makes the difference between a trace that fits and one that doesn’t.

Minimum trace width in standard photolithographic production on 1 oz copper is typically 3 mil (75 µm) trace and space, with specialist fabs holding 2 mil (50 µm) under tightly controlled conditions. The 35 µm copper requires careful etch control to maintain consistent line edge definition at fine pitch — more demanding than 0.5 oz but well within the capability of any flex-qualified production fab.

Impedance Design with a 0.5 mil Kapton Dielectric

The 0.5 mil Kapton core in LF7002R creates a very shallow dielectric — only 13 µm between the copper trace and any adjacent conductor or reference plane. For controlled impedance work, that means the height (H) parameter in your impedance equations is at its minimum, and your trace width requirements for a given impedance target will be narrower than on any 1 mil or 2 mil Kapton construction.

Run your impedance calculator with the following LF material parameters: Dk = 3.6 at 1 MHz, Dk = 3.0 at 10 GHz, copper thickness = 35 µm (1 oz). Tools such as Saturn PCB Toolkit and Polar Instruments Si9000e handle these inputs accurately. At 0.5 mil Kapton, the copper thickness-to-dielectric-height ratio is significant — do not use simplified thin-copper approximations. The 1 oz copper at 35 µm is 2.7× the dielectric thickness, which pushes you into terrain where a proper 2D field solver gives meaningfully different results than a simplified formula.

Stiffener and Coverlay Selection

LF7002R’s 0.5 mil acrylic adhesive requires matching attention on the coverlay side. At 35 µm copper post-etch, a coverlay with 0.5 mil adhesive provides marginal fill around trace edges at typical flex circuit trace pitches. For anything below 5 mil trace/space on 1 oz copper, most fabs prefer 1 mil coverlay adhesive on LF7002R to ensure complete void-free encapsulation between and around traces. Confirm with your fab based on their press capability and copper pattern density.

For component areas requiring stiffeners, use Pyralux LF sheet adhesive — the same acrylic adhesive family — to bond FR4, aluminum, or stainless steel reinforcement sections. Avoid epoxy-based adhesives in the stiffener bond unless your fab has confirmed compatibility with the acrylic system under your specific thermal profile.

Processing Parameters

Parameter	Specification
Lamination Temperature	182–199°C (360–390°F)
Lamination Pressure	14–28 kg/cm² (200–400 psi)
Time at Temperature	1–2 hours
Storage Temperature	4–29°C (40–85°F)
Maximum Humidity	Below 70% RH
Standard Sheet Sizes	24×36 in / 24×18 in / 12×18 in
Sheets Per Pack	4 minimum, 25 maximum
Warranty Period	2 years from shipment
Quality System	ISO 9001:2015 certified

The 0.5 mil acrylic adhesive in LF7002R has a smaller thermal mass than the 1 mil adhesive in LF9xxx constructions. In practice, that means the adhesive reaches cure temperature faster and can be more sensitive to press ramp rate variations. Work with your lamination equipment manufacturer to confirm that ramp rate profiles established for 1 mil adhesive constructions are still appropriate, or validate press performance with coupon peel strength testing when transitioning from LF9110R to LF7002R.

Typical Applications for DuPont Pyralux LF7002R

The specific combination of 1 oz current capacity with a 0.5 mil Kapton substrate places LF7002R firmly in a set of design scenarios where no single alternative construction hits all the requirements simultaneously:

Compact IoT and sensor node interconnects — Wireless sensor nodes, industrial IoT edge devices, and environmental monitoring instruments need flex interconnects that route power from a small LiPo cell alongside low-current signal traces. LF7002R handles both in a package thin enough to fit inside slim enclosures without stiffener reinforcement in the flex zone.

Medical wearables and skin-contact diagnostics — Continuous glucose monitors, cardiac patch monitors, and electrodermal activity sensors benefit from thin flex circuits that follow body contours without creating pressure or rigidity. The 1 oz copper supports the supply current requirements of modern BLE and ANT+ radio modules while the thin Kapton keeps the total build compliant.

Thin consumer electronics assemblies — Smart earbuds, compact hearing instruments, and slim-format smart glasses all represent designs where the board-to-board interconnect budget is measured in fractions of a millimeter. LF7002R fits these constraints while offering more current margin than LF7012R.

Rigid-flex inner layer application — In rigid-flex multilayer stackups where one or more inner flex layers need 1 oz copper for signal or power routing, LF7002R’s thin adhesive reduces the total laminate height contribution of each flex core — an important consideration when the overall board thickness is constrained by connector mating height or connector footprint Z-axis clearance.

Aerospace and satellite miniaturization — CubeSat and small satellite payloads where every milligram of interconnect mass matters benefit from LF7002R’s combination of 1 oz current capacity and minimum-mass substrate construction.

Useful Resources for Engineers Working with DuPont Pyralux LF7002R

Resource	Where to Access
Pyralux LF Datasheet (EI-10117, current rev.)	pyralux.dupont.com
Pyralux LF Technical / Processing Manual	Request from DuPont or Qnity sales representative
Pyralux Safe Handling Guide	pyralux.dupont.com
IPC-4204/1 Flexible Metal-Clad Dielectrics Spec	ipc.org
IPC-2223 Sectional Design Standard for Flex PCBs	ipc.org
IPC Test Methods TM-650	ipc.org
Pyralux Laminate Product Selector Tool	pyralux.dupont.com
Insulectro Pyralux LF Product Page	insulectro.com/products/pyralux-lf
DuPont PCB Materials Reference	DuPont PCB Guide — PCBsync

5 Frequently Asked Questions About DuPont Pyralux LF7002R

Q1: Is DuPont Pyralux LF7002R IPC-4204/1 certified?

No — LF7002R is not certified to IPC-4204/1 in the current DuPont catalog. This is consistent across all LF7xxx constructions that use the 0.5 mil Kapton dielectric (LF7012R, LF7002R, LF7004R, LF7022R). If your project requires IPC-4204/1 documentation, the closest certified single-sided alternative with 1 oz copper is LF7011R (1 oz / 0.5 mil adhesive / 1 mil Kapton) or the mainstream LF9110R (1 oz / 1 mil adhesive / 1 mil Kapton). Both are thicker but carry full IPC-4204/1 certification on standard production lots.

Q2: What is the main design advantage of LF7002R over LF7012R?

Both parts share the same 0.5 mil adhesive and 0.5 mil Kapton dielectric. The difference is copper weight: LF7002R uses 1 oz/ft² (35 µm) rolled-annealed copper versus LF7012R’s 0.5 oz/ft² (18 µm). That means LF7002R carries roughly twice the current at the same trace width for the same temperature rise. It also handles etch-defined fine features slightly differently — 1 oz copper gives you better trace edge definition stability at trace widths above 3 mil because the foil is more structurally rigid during the imaging and etching process. Choose LF7002R when current capacity is a design driver. Choose LF7012R when absolute minimum thickness is the primary constraint.

Q3: Can LF7002R be used in dynamic flex applications?

Yes. The “R” suffix designates rolled-annealed copper, which is the correct choice for any application involving repeated bending. RA copper has an elongated grain structure that resists fatigue cracking under cyclic stress far better than electro-deposited copper at the same thickness. For high-cycle dynamic flex (hundreds of thousands to millions of cycles), evaluate the specific bend radius, copper condition post-etch, and coverlay construction against IPC-2223 guidelines for dynamic flex design. Test coupons under representative bending conditions before committing to production volumes on any ultra-thin laminate used in dynamic service.

Q4: How does the 0.5 mil Kapton affect my impedance calculations for LF7002R?

Significantly. At 13 µm dielectric height, the Kapton in LF7002R is only 37% of the dielectric height in a standard LF9110R construction (25 µm). For a 50Ω microstrip target with Dk = 3.6, the required trace width will be much narrower on LF7002R than on LF9110R. At this dielectric height, copper thickness (35 µm for 1 oz) represents a substantial fraction of the total height H, so always use a tool that accounts for finite copper thickness — simplified Wadell or Wheeler equations will give you incorrect results. Saturn PCB Toolkit and Polar Si9000e both handle this correctly if you set the dielectric and copper parameters accurately.

Q5: What is the difference between LF7002R and LF7010R?

LF7010R is the double-sided version of the 1 oz / 0.5 mil adhesive sub-series, but with a 1 mil (25 µm) Kapton core rather than 0.5 mil. The constructions differ on both the number of copper layers (LF7002R is single-sided; LF7010R is double-sided) and the Kapton thickness. LF7010R is also IPC-4204/1 certified, which LF7002R is not. If your design needs routing on both sides of a thin flex construction with 1 oz copper, and IPC certification matters, LF7010R is the part to specify. LF7002R is the right choice when you need a single-sided build at the absolute minimum dielectric height.

Engineering Summary

DuPont Pyralux LF7002R occupies a specific and deliberate niche in the flex laminate selection matrix: full 1 oz current capacity on the thinnest available acrylic adhesive / Kapton substrate in the LF series. It is not a material you’d reach for on a general-purpose flex connector where LF9110R or LF7011R does the job with better IPC credentials. But for thin-format designs where 0.5 oz copper simply cannot carry the current load and every additional mil of total thickness represents a real engineering problem, LF7002R is precisely the right call. Specify it accurately, work with a fabricator who understands ultra-thin acrylic laminate processing, and apply IPC-2223 bend radius principles to your flex zone geometry — and this material will deliver exactly what it promises.