Inquire: Call 0086-755-23203480, or reach out via the form below/your sales contact to discuss our design, manufacturing, and assembly capabilities.
Quote: Email your PCB files to Sales@pcbsync.com (Preferred for large files) or submit online. We will contact you promptly. Please ensure your email is correct.
Notes: For PCB fabrication, we require PCB design file in Gerber RS-274X format (most preferred), *.PCB/DDB (Protel, inform your program version) format or *.BRD (Eagle) format. For PCB assembly, we require PCB design file in above mentioned format, drilling file and BOM. Click to download BOM template To avoid file missing, please include all files into one folder and compress it into .zip or .rar format.
If you’ve been spec-ing PCB materials for a high-layer-count multilayer board and stumbled across Arlon 45N, you’re in the right place. This guide cuts through the datasheet noise and explains what this material actually does, why engineers choose it, how it stacks up against polyimide alternatives, and where it fits in real-world board design. Whether you’re building automotive under-hood electronics, backplanes, or BGA-heavy boards, you’ll find what you need here.
What Is Arlon 45N? A Quick Overview for PCB Engineers
Arlon 45N is a tough, high-Tg multifunctional epoxy laminate and prepreg system developed by Arlon Electronic Materials Division (EMD). It’s categorized under Arlon’s Epoxy Products line — not to be confused with the company’s dedicated Low Flow Polyimide line (37N/38N) or its pure polyimide systems (85N/85HP).
That said, 45N is frequently evaluated alongside polyimide prepregs by engineers who need higher thermal performance than standard FR-4 but don’t necessarily require the extreme heat resistance of a full polyimide system. It bridges a very real gap in the material selection ladder.
Arlon 45N is a tough, high Tg (175°C by DSC) multifunctional epoxy laminate and prepreg system designed for use in a variety of higher layer count MLBs, processable using conventional FR-4 conditions. That last point matters a lot operationally — your fab shop doesn’t need special press cycles, special drills, or a whole new set of process instructions. You get upgraded thermal performance without retooling your production line.
Arlon Electronic Materials Division, a veteran-owned business founded in 1969, is a major manufacturer of specialty high-performance laminate and prepreg materials used in a wide variety of printed circuit board applications. The 45N product is one of their most versatile commercial offerings and has been in continuous production use across automotive, industrial, and high-reliability commercial applications.
Understanding the “Low Flow” and “Polyimide” Context
One reason engineers often search for “Arlon 45N Low Flow Polyimide Prepreg” together is because Arlon’s product portfolio covers both categories, and the terms get mixed when comparing options at the material selection stage.
Here’s a quick orientation to where 45N sits within the broader Arlon family:
Product
Type
Tg (DSC)
IPC Spec
Primary Use
45N
Multifunctional Epoxy
175°C
IPC-4101/26
High layer count MLB, automotive, BGA
37N
Low Flow Polyimide Prepreg
199°C
IPC-4101/40
Rigid-flex bonding
38N
2nd Gen Low Flow Polyimide
199°C
IPC-4101/42
Rigid-flex, aerospace
47N
Modified Epoxy Low-Flow
135°C
IPC-4101/26
Low-temperature bonding
49N
Multifunctional Epoxy Low-Flow
170°C
IPC-4101/26
Heat sink bonding
51N
Non-DICY Epoxy Low-Flow
170°C
IPC-4101/126
Lead-free rigid-flex
85N
Pure Polyimide
250°C
IPC-4101/40,41
Aerospace, military, space
Arlon’s 38N is the second-generation 200°C glass transition temperature polyimide low-flow resin system designed to improve adhesion and bond strength to Kapton polyimide films, copper, and other metals, with applications in military, aerospace, space, commercial, and industrial PWB electronics.
Arlon 45N occupies the commercial-grade high-performance slot. It’s the material you reach for when FR-4 isn’t enough but a full polyimide build isn’t justified by the budget or application requirements.
Arlon 45N Key Properties: Full Technical Breakdown
Thermal Properties
Thermal performance is where 45N earns its place in demanding designs. The Arlon 45N PCB Material has a glass transition temperature of 175°C and at 50–260°C, a Z-axis expansion of 2.4%, with CTE of 14–16 ppm/°C on the X,Y axis, 55 ppm/°C below Tg on the Z-axis, and 200 ppm/°C above Tg on the Z-axis.
Thermal Property
Value
Glass Transition Temperature (Tg by DSC)
175°C
Thermal Decomposition (Td at 5%)
>300°C
Z-Axis Expansion (50–260°C)
2.4%
CTE X,Y Axis
14–16 ppm/°C
CTE Z-Axis (<Tg)
55 ppm/°C
CTE Z-Axis (>Tg)
200 ppm/°C
The 175°C Tg is a meaningful upgrade from standard FR-4 (typically 130–140°C). For lead-free assembly processes where peak reflow temperatures hit 260°C+, this thermal headroom reduces the risk of barrel cracking, inner-layer delamination, and via reliability failures.
Electrical Properties
The Arlon 45N’s dielectric constant falls between 4.2 and 4.6 at 1 MHz. It has a volume resistivity of 2.6 × 10⁷ MΩ-cm for C96/35/90, while at E24/125, it has a volume resistivity of 3.3 × 10⁷ MΩ-cm.
Surface resistivity values are 2.9 × 10⁷ MΩ at E24/125 and 4.0 × 10⁴ MΩ at C96/35/90, with a Poisson’s Ratio of 0.2 and Young’s Modulus of 2.8 (CD/MD).
Electrical Property
Value
Dielectric Constant (1 MHz)
4.2 – 4.6
Volume Resistivity (C96/35/90)
2.6 × 10⁷ MΩ-cm
Volume Resistivity (E24/125)
3.3 × 10⁷ MΩ-cm
Surface Resistivity (E24/125)
2.9 × 10⁷ MΩ
Surface Resistivity (C96/35/90)
4.0 × 10⁴ MΩ
For signal integrity engineers: 45N is not a low-loss material for RF or high-speed differential designs. It’s intended for digital multilayer and power board applications where controlled impedance at standard logic speeds is the requirement, not sub-GHz microwave performance.
Mechanical Properties
Peel strength with respect to copper is 8 N/mm after thermal stress, at elevated temperatures, and after process solutions.
Mechanical Property
Value
Young’s Modulus (CD/MD)
2.8
Poisson’s Ratio
0.2
Peel Strength (Copper, post thermal stress)
8 N/mm
The peel strength data is important for any design going through multiple thermal cycles — automotive under-hood boards, for example, can see thousands of thermal excursions across the product lifetime.
Compliance and Certification
Arlon 45N features high Tg by DSC (175°C), resists barrel cracking and inner layer copper cracking during fabrication, is resistant to measling and solder shock defects, suitable for most lead-free applications, and is RoHS/WEEE compliant.
Standard
Status
IPC-4101/26
Meets requirements
RoHS Compliance
Yes
WEEE Compliance
Yes
Flammability Rating
UL 94 V-0
Water Absorption
0.1%
Arlon 45N Datasheet: Available Prepreg Styles
Arlon 45N prepreg is offered on standard fiberglass fabric styles. The most common styles are listed below — availability may vary by distributor or fab shop.
Fabric Style
Nominal Thickness (mil)
Resin Content (%)
Typical Use
106
2.0–2.5
73–78
Fine-pitch, thin dielectric
1080
3.0–3.5
65–70
Standard MLB inner layers
2113
4.0–5.0
52–58
Core bonding
2116
4.5–5.5
48–54
Standard build-up
7628
6.5–7.5
40–46
Thicker dielectric, high pressure cure
For official prepreg style availability tables and resin content per lot, always refer to the current Arlon 45N datasheet directly (linked in the Resources section below).
Arlon 45N Process Conditions: What Your Fab Shop Needs to Know
This is where 45N wins friends on the production floor. The lamination cycle is compatible with conventional FR-4 press cycles, which means shorter qualification cycles at your fabricator.
Inner-Layer Preparation
Process inner layers through standard develop, etch, and strip sequences. Use brown oxide on all inner layers and adjust dwell time in the oxide bath to achieve a uniform, consistent coating. Bake inner layers in a rack for 60 minutes at 225°F–250°F (107°C–121°C) immediately prior to lay-up, and vacuum desiccate the prepreg for 8–12 hours prior to lamination.
Lamination Cycle
The lamination cycle for Arlon 45N is as follows: pre-vacuum for 30 minutes; control heat rise to 8°F–12°F (4.5°C–6.5°C) per minute between 210°F and 300°F (100°C and 150°C); product temperature at start of cure = 360°F (180°C); cure time at temperature = 90 minutes; cool down under pressure at ≤ 12°F/min (6°C/min).
Parameter
Specification
Pre-vacuum
30 minutes
Heat Rise Rate
8–12°F/min (4.5–6.5°C/min)
Cure Start Temperature
360°F (180°C)
Cure Time
90 minutes
Cooldown Rate
≤ 12°F/min (6°C/min)
Vacuum-assisted lamination is strongly recommended. The controlled heat-up rate between 100°C and 150°C is critical — too fast and you risk resin flow issues; too slow and you extend cycle time unnecessarily.
Drilling and De-smear
Drill at 350 SFM. Undercut bits are recommended for vias 0.018″ (0.45mm) and smaller. De-smear using alkaline permanganate or plasma with settings appropriate for multifunctional epoxy — slightly longer dwell times may be required compared with difunctional FR-4 systems.
Arlon 45N vs. Competing Materials: How Does It Stack Up?
Arlon 45N vs. Standard FR-4
Standard FR-4 remains the industry workhorse, but it tops out at around 130–140°C Tg and becomes unreliable through multiple lead-free reflow cycles on thick or high-layer-count boards. Arlon 45N’s 175°C Tg provides a substantial safety margin. The processing similarity means you’re not paying a premium in cycle time or new tooling — just in material cost, which is modest at this performance tier.
Arlon 45N vs. Arlon 49N (Low-Flow Multifunctional Epoxy)
Arlon’s 49N is a low-flow epoxy prepreg engineered for bonding multilayer epoxy rigid-flex or attaching heat-sinks to multilayer epoxy PCBs, with a high glass transition temperature of 170°C, and is well suited for high-layer count rigid-flex applications where z-axis expansion is a concern.
If controlled resin flow is critical — you’re bonding rigid to flex sections or attaching metal heat-sinks — 49N is the better pick. If you’re building a standard multilayer where dielectric integrity and Tg are the primary requirements, 45N’s higher Tg (175°C vs. 170°C) and standard press conditions give it an edge.
Arlon 45N vs. Arlon 85N (Pure Polyimide)
Arlon’s 85N is a 250°C high glass transition pure polyimide resin system that provides superior thermal resistance to high-temperature end-use electronics, and is the best choice for high-layer count multilayers with long service life for aerospace, military, space, and other applications where reliable thermal stability is required.
85N is in a different class entirely — aerospace, military, and space-grade hardware where 250°C Tg is a hard requirement. Processing is more demanding, cost is significantly higher, and the design rules differ. For most commercial and automotive-grade electronics, 45N is more than adequate and considerably easier to fabricate.
Summary Comparison Table
Material
Tg (°C)
Td (°C)
Z CTE
Water Abs.
Typical Application
Arlon 45N
175
>300
2.4%
0.1%
High-count MLB, automotive, BGA
FR-4 (standard)
130–140
~300
3.0–4.5%
0.1–0.2%
General commercial PCBs
Arlon 49N
170
302
~2.5%
0.1%
Heat sink bonding, rigid-flex
Arlon 37N
199
320
<1%
<1%
Rigid-flex, polyimide systems
Arlon 85N
250
>400
<2%
0.1%
Military, aerospace, space
Arlon 45N Applications: Where Engineers Actually Use This Material
The Arlon 45N PCB Material finds relevance in a wide range of critical applications, including motherboards, backplanes, BGA packaging, multilayer boards with high layer counts, and automotive applications.
#### Automotive Electronics
Under-hood automotive applications are one of the most demanding commercial electronics environments. Temperature cycling, vibration, and long service life requirements push FR-4 to its limits. 45N’s 175°C Tg and excellent resistance to barrel cracking make it a common spec for engine control units (ECUs), transmission controllers, and power distribution modules.
#### Backplanes and Motherboards
High-layer-count backplanes — think 20+ layers in server infrastructure or industrial control systems — accumulate thermal stress through multiple lamination and reflow cycles. The tighter Z-axis CTE of 45N (2.4% vs. FR-4’s typical 3.0–4.5%) means better via reliability and longer service life in these dense builds. For engineers designing Arlon PCB solutions for telecom or data center infrastructure, 45N is a natural default upgrade from standard FR-4.
#### BGA and Fine-Pitch Component Packaging
Ball grid array packages demand dimensional stability during assembly reflow. The combination of low moisture absorption (0.1%) and high Tg in 45N reduces the risk of moisture-driven delamination events during high-temperature assembly — a failure mode that haunts BGA designs built on marginal FR-4 laminates.
#### Industrial and Commercial High-Reliability Electronics
Any application where the board must survive extended thermal cycling, exposure to elevated ambient temperatures, or prolonged field life fits the 45N profile. Industrial power electronics, motor drives, and energy infrastructure boards benefit from the improved thermal margin without requiring the cost and process complexity of polyimide systems.
Storage, Handling, and Shelf Life
Prepreg shelf life is a real operational concern, especially in lower-volume specialty shops. Arlon 45N prepreg should be stored at 60–70°F (15–21°C) at or below 30% relative humidity. Vacuum desiccation for 8–12 hours before lamination is strongly recommended and is not optional for critical builds.
Improper storage — warm temps, high humidity — will advance the resin cure state, reducing resin flow during lamination and potentially causing voids or delamination. Always check lot date codes and condition prepreg appropriately before committing to a high-layer-count press run.
No — Arlon 45N is a multifunctional epoxy laminate and prepreg, not a polyimide. It is often compared with polyimide systems because it targets the higher-performance end of the epoxy spectrum, but engineers who need true polyimide performance (Tg of 200°C+, chemical resistance to polyimide flex substrates) should look at Arlon’s 37N, 38N, or 85N products instead. 45N fills the gap between standard FR-4 and polyimide for cost-sensitive high-reliability designs.
2. Can Arlon 45N be processed on standard FR-4 lamination equipment?
Yes, and that’s one of its strongest selling points. Arlon 45N is processable using conventional FR-4 lamination conditions, which means existing press equipment, drills, and de-smear lines work without modification. The lamination cycle parameters (180°C cure start, 90-minute cure time) are well within the range of standard hydraulic and vacuum-assist presses.
3. What is the IPC specification for Arlon 45N?
Arlon 45N meets the requirements of IPC-4101/26. This slash sheet defines requirements for multifunctional epoxy base materials and is the relevant qualification standard when your customer or program requires IPC material certification documentation.
4. How does Arlon 45N perform in lead-free assembly?
Very well for the epoxy class. Arlon 45N resists barrel cracking and inner layer copper cracking during fabrication, is resistant to measling and solder shock defects, and is suitable for most lead-free applications. The 175°C Tg provides meaningful margin above typical lead-free peak reflow temperatures of 245–260°C, and the low 0.1% water absorption reduces the risk of explosive delamination (popcorning) during high-temperature assembly cycles.
5. What is the difference between Arlon 45N and Arlon 44N?
Arlon’s 44N is a high resin content multifunctional (175°C) epoxy prepreg system with a proprietary microdisperse ceramic filler system, engineered for filling clearance holes in thin metal cores such as 0.006-inch copper-invar-copper or via holes in sequentially laminated MLB designs, and is based on Arlon’s 45N. In other words, 44N is a filled derivative of 45N designed specifically for hole-fill applications. If you’re bonding standard multilayer inner layers, 45N is the right choice. If you’re filling vias or clearance holes in metal-core or sequentially laminated boards, 44N is purpose-built for that task.
Final Thoughts: Is Arlon 45N Right for Your Design?
If your design sits in that frustrating zone where standard FR-4 is leaving thermal margin on the table but you don’t have the budget, schedule, or process infrastructure for a full polyimide build, Arlon 45N is worth a serious look. The 175°C Tg, excellent lead-free compatibility, IPC-4101/26 certification, and FR-4-compatible processing make it one of the most practical upgrades available in the epoxy class.
For engineers working on automotive, industrial backplanes, BGA-dense consumer electronics, or any high-layer-count board that needs to survive real-world thermal stress, this material consistently delivers. The low moisture absorption and strong copper peel strength mean it’s not just thermally robust — it holds together mechanically through the full assembly and service lifecycle.
When comparing to Arlon’s broader product family, remember: 45N is your go-to epoxy upgrade, 49N or 51N is where you go when controlled resin flow is the primary requirement, and the 37N/38N/85N polyimide products step in when the application genuinely demands polyimide-class performance.
Inquire: Call 0086-755-23203480, or reach out via the form below/your sales contact to discuss our design, manufacturing, and assembly capabilities.
Quote: Email your PCB files to Sales@pcbsync.com (Preferred for large files) or submit online. We will contact you promptly. Please ensure your email is correct.
Notes: For PCB fabrication, we require PCB design file in Gerber RS-274X format (most preferred), *.PCB/DDB (Protel, inform your program version) format or *.BRD (Eagle) format. For PCB assembly, we require PCB design file in above mentioned format, drilling file and BOM. Click to download BOM template To avoid file missing, please include all files into one folder and compress it into .zip or .rar format.
