DuPont Pyralux AP7164E: The Complete PCB Engineer’s Guide to 0.33 oz ED Copper / 1 mil Polyimide Flex Circuit Material

If you’ve been specifying flex circuit laminates for any length of time, you already know that picking the right copper weight and dielectric thickness isn’t just a box-checking exercise — it has real downstream consequences on etch resolution, impedance control, and assembly yield. DuPont Pyralux AP7164E sits in a particularly useful spot in the AP product family: 0.33 oz (12 µm) electro-deposited (ED) copper on a 1 mil (25 µm) polyimide dielectric, double-sided, adhesiveless. This guide breaks down what that combination actually means on the shop floor and when you should reach for it.

What Is DuPont Pyralux AP7164E? Product Overview and Construction

DuPont Pyralux AP7164E is a double-sided, copper-clad laminate from the all-polyimide Pyralux AP series. Its construction is adhesiveless — the copper is bonded directly to the polyimide without an intermediate acrylic or epoxy layer. That single fact is responsible for most of the material’s performance advantages over adhesive-based laminates like Pyralux LF or FR.

The “AP” in the product code stands for All-Polyimide, which tells you the dielectric is 100% polyimide — the same base chemistry as DuPont Kapton film. The adhesiveless construction means there’s no lower-glass-transition-temperature adhesive layer to degrade under thermal cycling, which is why the AP series is the go-to for aerospace, defense, medical, and 5G hardware.

The “7164E” suffix encodes the construction:

• 71 → 1 mil (25 µm) polyimide dielectric
• 64 → 12 µm (0.33 oz/ft²) copper
• E → Electro-Deposited (ED) copper foil

Understanding the suffix system helps you quickly navigate the broader AP product table when you need to step up to 0.5 oz or drop to 0.25 oz copper.

DuPont Pyralux AP7164E Full Technical Specifications

The table below consolidates the critical properties for AP7164E. These values are based on the DuPont AP technical data sheet and are typical for this construction — individual lots may vary slightly.

Property	Value	Test Method
Dielectric Thickness	1.0 mil (25 µm)	—
Copper Thickness	12 µm / 0.33 oz/ft²	—
Copper Type	Electro-Deposited (ED)	—
Construction	Double-sided, adhesiveless	—
Max Operating Temperature	180°C (356°F)	UL 796
Glass Transition Temp (Tg)	220°C	—
In-Plane CTE (T < Tg)	~25 ppm/°C	—
Dielectric Constant (1 MHz)	~3.4	IPC-TM-650
Loss Tangent (1 MHz)	~0.002	IPC-TM-650
Peel Strength	See TDS	IPC-TM-650
Flexural Endurance (min.)	6,000 cycles	IPC-TM-650
Modulus	~700 kpsi	—
Chemical Resistance	Pass, >95%	24-hr immersion
Flammability	UL 94V-0	UL 94
IPC Certification	IPC-4204/11	—
Quality System	ISO 9001:2015	—

The 220°C Tg is the headline thermal number. It’s meaningfully higher than adhesive-based flex materials, which typically Tg out around 100–130°C. That gap matters when you’re running lead-free reflow profiles (peak 260°C solder temp) or operating in a hot underhood automotive environment.

How AP7164E Fits Into the Broader Pyralux AP Product Family

One of the most common points of confusion when specifying AP materials is understanding where AP7164E sits relative to its neighbors. The AP series is organized by dielectric thickness (1–6 mil range) and copper weight. AP7164E shares the 1 mil dielectric with several siblings:

Product Code	Dielectric (mil)	Copper (µm / oz)	Copper Type
AP7163E	1.0	9 µm / 0.25 oz	ED
AP7164E	1.0	12 µm / 0.33 oz	ED
AP8515R	1.0	18 µm / 0.5 oz	RA
AP9111R	1.0	35 µm / 1.0 oz	RA

Key takeaway: AP7164E and AP7163E are the two thin-copper ED options at 1 mil dielectric. When you need even thinner copper for ultra-fine lines or antenna structures, you step down to AP7163E (0.25 oz). When you need higher current capacity or more robust traces, you move up to the RA copper options at 0.5 oz or 1 oz.

ED vs. RA Copper: Why AP7164E Uses Electro-Deposited Foil

The “E” suffix matters. ED (electro-deposited) copper is manufactured electrochemically, producing a fine-grained columnar grain structure. Compared to rolled-annealed (RA) copper:

• ED copper provides superior fine-line resolution and more uniform surface roughness — ideal for photolithographic etching of tight trace/space geometries
• RA copper offers superior ductility and fatigue resistance under dynamic flexing

This means AP7164E is not the right choice for dynamic flex zones where the circuit will see millions of bend cycles. For those applications, reach for AP8515R (RA copper). AP7164E excels in static flex, rigid-flex stackups, and fine-pitch density applications.

Design and Fabrication Considerations for AP7164E

Minimum Trace/Space and Etch Resolution

The 0.33 oz (12 µm) copper weight is one of the thinner practical commercial thicknesses. Thinner copper etches faster and with better sidewall control, enabling tighter trace/space geometries compared to heavier copper. For reference, most fabricators achieving 3 mil trace/space on 0.5 oz copper can push to 2–2.5 mil geometries on 0.33 oz, given good process control.

This is one of the primary reasons to specify AP7164E over a heavier copper variant when you’re routing high-density flex with fine-pitch BGAs or high-density connector fields.

Controlled Impedance Design on 1 mil Dielectric

The 1 mil polyimide dielectric and the AP series’ tight thickness tolerance (DuPont notes this as a key advantage versus competitive materials at 15–20% tolerance) make AP7164E well-suited for microstrip impedance designs. With a dielectric constant around 3.4, a typical 50Ω microstrip on 1 mil dielectric requires a relatively narrow trace — which aligns well with the fine-line capability of the 0.33 oz ED copper.

Multilayer Flex and Rigid-Flex Stackup Compatibility

AP7164E is fully compatible with standard flex circuit fabrication processes including oxide treatment and wet chemical processing. The low CTE (~25 ppm/°C in-plane) is critical for rigid-flex designs: a close CTE match between the flex core and FR4 rigid sections minimizes interfacial stress during thermal cycling and assembly.

For multilayer rigid-flex builds, DuPont PCB  materials are commonly paired with high-performance flex cores like AP7164E in the rigid sections, providing a complementary thermal and mechanical property set.

Storage and Handling

DuPont Pyralux AP laminates are warranted for two years from manufacturing date when stored at 4–29°C (40–85°F) and below 70% relative humidity. The material does not require refrigeration. During processing, ensure lamination areas are well-ventilated — trace residual solvents typical of polyimide chemistry can volatilize under press lamination temperatures.

Primary Application Areas for DuPont Pyralux AP7164E

Industry Segment	Typical Application
Aerospace & Defense	Satellite flex harnesses, avionics flex interconnects, radar sensor arrays
Medical Devices	Imaging system flexible circuits, diagnostic wearables, surgical robotics
5G & Telecom	Antenna flex circuits, mmWave interconnects, high-frequency RF flex
Automotive	ECU flex circuits, ADAS sensor interconnects, in-cabin control electronics
Consumer Electronics	High-density smartphone flex, camera module interconnects

The adhesiveless, all-polyimide construction makes AP7164E particularly suited for any application where chemical resistance, dimensional stability, and long-term thermal reliability matter more than the lowest possible material cost.

DuPont Pyralux AP7164E vs. Competing Flex Materials

When evaluating AP7164E, engineers typically compare it against adhesive-based alternatives and other thin-copper flex laminates:

Parameter	AP7164E (Adhesiveless PI)	Adhesive-Based Flex (e.g., Pyralux LF)	Standard FR4 Flex Core
Tg	220°C	~100–130°C	~135–175°C
CTE Match for Rigid-Flex	Excellent	Moderate	Poor (glass-filled)
Fine-Line Resolution	Excellent (ED foil)	Good	Limited
Dynamic Flex Cycles	Moderate (ED foil)	Good (RA available)	Not recommended
Chemical Resistance	Excellent	Good	Moderate
IPC Certification	IPC-4204/11	Varies	IPC-4101
Typical Cost	Premium	Lower	Lowest

The cost premium for AP7164E is real, but in high-reliability applications it’s almost always justified when you factor in qualification, rework, and field failure costs.

Useful Resources for Engineers Specifying AP7164E

Here are direct reference links you should have bookmarked when working with DuPont Pyralux AP materials:

• DuPont Pyralux AP Official Product Page: https://www.dupont.com/electronics-industrial/pyralux-ap.html
• DuPont Pyralux AP Technical Data Sheet (PDF): Available via pyralux.dupont.com — search for “AP double-sided clad TDS”
• IPC-4204/11 Standard: The IPC certification standard applicable to adhesiveless polyimide copper-clad laminates — available through IPC.org
• IPC-2223 Sectional Design Standard for Flexible Printed Boards: Critical reference for flex circuit design rules — IPC.org
• IPC-6013 Qualification & Performance for Flexible Printed Boards: Acceptance criteria for manufactured flex boards — IPC.org
• DuPont Pyralux Safe Handling Guide: Available at pyralux.dupont.com
• UL Product iQ: Verify UL 94V-0 and UL 796 certifications for Pyralux AP materials at iq.ul.com

5 FAQs About DuPont Pyralux AP7164E

1. Can AP7164E be used in dynamic flex applications?

Not ideally. The “E” suffix indicates electro-deposited copper foil, which has lower ductility than rolled-annealed (RA) copper. For circuits that will undergo continuous or high-cycle dynamic flexing, AP8515R (0.5 oz RA copper, 1 mil dielectric) is a better choice. AP7164E is well-suited for static flex and rigid-flex where the flex zones are only bent once or a small number of times during assembly.

2. What’s the practical etching advantage of 0.33 oz copper on flex?

Thinner copper reduces undercut during wet chemical etching, which translates directly to tighter achievable trace/space ratios. If your design calls for anything below 3 mil trace/space, 0.33 oz copper gives your fabricator significantly more process latitude than 0.5 oz or 1 oz. It also improves uniformity of etch across fine-pitch structures.

3. How does AP7164E perform in lead-free reflow assembly?

Very well. The 220°C Tg is comfortably above standard lead-free peak reflow temperatures (~260°C peak), and the adhesiveless construction means there’s no lower-Tg adhesive layer to soften or delaminate. Dimensional stability through multiple reflow passes is one of the hallmark advantages of the AP series over adhesive-based flex materials.

4. Is DuPont Pyralux AP7164E RoHS compliant?

Yes. DuPont Pyralux AP materials do not contain polybrominated biphenyls (PBBs) or polybrominated biphenyl oxides (PBBOs). However, always request the current compliance documentation from your distributor to confirm the specific lot you’re receiving meets your project’s compliance requirements.

5. What roll and sheet sizes are AP7164E available in?

Standard roll widths for Pyralux AP products are typically 250 mm (9.84 in) and 500 mm (19.68 in), with roll lengths of 50 m or 100 m on a standard core. Sheet sizes and custom widths are available by special order through DuPont’s authorized distribution network. If you’re running a high-mix, low-volume prototype program, many flex fabricators stock AP material and sell cut pieces.