4mm PP Hollow Sheet — The Thinnest Self-Supporting Corrugated Polypropylene Board
Le Plaque creuse en PP de 4 mm is the thinnest gauge of polypropylene corrugated board that stands on its own without a supporting frame. At approximately 0.65 kg/m² , it provides the rigidity and flatness that 2–3 mm sheets cannot achieve without external reinforcement — yet it weighs roughly 30 % less than the 5 mm alternative , reducing both material cost and shipping weight across every pallet.
This makes 4 mm the cost-optimal thickness for a wide range of standard packaging applications: electronics component trays, courier box liners, agricultural turnover crate inserts, and retail product dividers . It is the thickness most OEM specifiers default to when they need “a PP corrugated board that holds its shape” — strong enough to protect, light enough to ship, and inexpensive enough to specify at scale.
Manufactured from 100 % recyclable polypropylene (PP recycling code 5) , PPBOXY’s 4mm hollow sheet is waterproof, chemically inert, and rated for −20 °C to +80 °C continuous service — making it suitable for refrigerated logistics and outdoor staging where cardboard degrades. Every sheet is available in custom lengths up to 6000 mm , widths up to 2100 mm, and colors matched to your Pantone reference.
Caractéristiques techniques
Caractéristiques techniques
Détails
Matériau 100 % recyclable polypropylene (PP) corrugated/twin-wall sheet
Épaisseur 4 mm (±0.2 mm tolerance)
Weight ~0.65 kg/m²
Standard Size 4×8 ft (1220 × 2440 mm)
Custom Size Range 500 mm × 500 mm up to 2100 mm × 6000 mm
Available Colors White, blue, black, red, green, yellow, custom Pantone
Plage de températures −20 °C to +80 °C
Absorption d'eau < 0.01 % (virtually zero)
Chemical Resistance Oils, solvents, weak acids, weak alkalis
Capacité de charge ~15 kg uniform load (400 × 600 mm panel, edge-supported)
Self-Supporting Yes — holds flat without frame
Foldable Possible along score line, but not the preferred choice for folding
Print Compatibility Screen printing (standard); digital/offset (Corona-treated option)
ESD Option Available (carbon-loaded PP, 10⁶–10⁹ Ω/sq)
Food Contact EU 10/2011 & FDA 21 CFR 177.1520 compliant
Recyclabilité PP recycling code 5 — fully recyclable
Réutilisabilité 50–100+ cycles
Quantité minimale de commande No minimum order quantity
Certifications SGS, ISO 9001, REACH, RoHS
Why 4 mm? The Self-Supporting Sweet Spot Between 3 mm and 5 mm
Choosing the right PP corrugated thickness is not simply “thicker = better.” Each millimetre increment changes the board’s structural behaviour, cost profile, and best-fit applications. The table below shows where 4 mm fits — and why it is the most frequently specified thickness in packaging and logistics.
Propriété
3 mm PP Sheet
4 mm PP Sheet 5 mm PP Sheet
Self-supporting? ❌ No — requires frame or folding
✅ Yes — holds flat without support ✅ Yes — greater rigidity
Foldable by hand? ✅ Yes — score-and-snap
⚠️ Possible along score line, but not preferred
❌ No — too thick to fold cleanly
Weight (approx.) ~0.45 kg/m²
~0.65 kg/m² ~0.85 kg/m²
Relative material cost Lowest
Optimal — best rigidity-per-dollar ~30 % higher than 4 mm
Flat surface for printing Moderate — slight flex
Excellent — stable flat surface Excellent — very stable
Best for Foldable boxes, curved forms
Flat inserts, tray liners, self-standing panels Heavy loads, reusable pallets, printed signage
Typical application Foldable courier boxes
Electronics trays, crate inserts, dividers Layer pads, printed boards, industrial dividers
Key takeaway : If your application requires a board that lies flat under its own weight without bowing — and you don’t want to pay for the extra 30 % material cost of 5 mm — 4 mm is the engineering and economic optimum.
Need a board you can fold into a box? See our Plaque ondulée en PP de 3 mm . Need a premium surface for high-resolution printing? See our 5mm Polypropylene Sheet with Corona treatment .
Key Features of the 4mm PP Hollow Sheet
Self-Supporting Flatness Without a Frame
The 4 mm twin-wall structure provides enough section modulus to span open areas without sagging — a capability that 2–3 mm sheets lack. In practical terms, a 400 mm × 600 mm panel of 4 mm PP hollow sheet laid across a 350 mm gap will support over 15 kg of uniformly distributed load without visible deflection. This eliminates the need for secondary support structures in tray and divider applications, reducing assembly time and part count.
Weight-Optimal at ~0.65 kg/m²
At approximately 0.65 kg/m² , the 4 mm sheet is light enough for manual handling in high-volume packing lines while providing 40–60 % more rigidity than 3 mm sheets. For a typical electronics factory packing 2,000 units/day, switching from 5 mm to 4 mm tray inserts saves roughly 400 kg of daily shipping weight — a tangible cost reduction that compounds across every shipment.
Waterproof & Chemically Inert
Polypropylene’s closed-cell fluted core absorbs zero moisture (water absorption < 0.01 %), unlike solid fibreboard or cardboard that softens and warps in humid environments. The PP resin resists oils, weak acids, weak alkalis, and common solvents, making 4 mm sheets suitable for automotive parts trays, chemical packaging inserts, and food-contact applications (EU 10/2011 and FDA 21 CFR 177.1520 compliant).
Standard 4×8 ft & Custom Sizes
PPBOXY stocks the industry-standard 4×8 ft (1220 × 2440 mm) format for immediate availability, with custom sizes up to 2100 mm width × 6000 mm length available on order. Common industry-specific cuts include:
Application
Typical Cut Size
Use Case
Electronics tray insert
400 × 600 mm
PCB and component separation
Courier box liner
400 × 300 mm
Inner wall and base protection
Agricultural crate divider
500 × 350 mm
Produce separation in turnover crates
Retail product display
1200 × 800 mm
Free-standing shelf/back panel
Color Options for Visual Coding & Branding
Available in white, blue, black, red, green, yellow, and custom Pantone-matched colors , 4 mm sheets serve double duty as visual management tools in warehouse and production environments. Color-code by product line, inspection status, or hazard class while simultaneously providing physical protection. White is the most common choice for printing and general packaging; blue and black are preferred for industrial and outdoor applications where UV resistance is required.
Industry Applications for 4mm PP Hollow Sheet
Electronics & Semiconductor Packaging
4 mm is the default thickness for electronics tray inserts and component dividers — rigid enough to hold PCBs flat without warping, thin enough to minimize package bulk. The waterproof surface prevents moisture-related failures during transit and storage, and the non-outgassing polypropylene is safe for cleanroom-adjacent handling. For ESD-sensitive components, PPBOXY offers carbon-loaded 4 mm sheets with surface resistivity of 10⁶–10⁹ Ω/sq.
Courier & E-Commerce Packaging
In high-volume courier operations, 4 mm PP hollow sheet is used as inner liners, base pads, and structural dividers within corrugated plastic boxes. Unlike cardboard inserts that degrade after a single trip, 4 mm PP liners are reusable for 50–100+ cycles , dramatically reducing per-shipment packaging cost. The self-supporting flatness ensures product presentation quality without additional framing. Pair with our Correx Fragile Delivery Box for complete fragile-item protection.
Agricultural Turnover Crates
4 mm sheet is the standard divider material inside PP corrugated agricultural crates — it separates produce layers without adding excessive weight to manual handling. The waterproof surface withstands hydrocooling and washdown protocols, and the chemical resistance tolerates sanitizing agents used in post-harvest processing. See our Emballages agricoles collection for complete crate solutions.
Automotive Parts Trays & Separators
In automotive assembly and parts logistics, 4 mm PP sheet functions as inter-layer separators and protective sleeves for machined components — pistons, gaskets, bearings, and stamped parts. The flat, non-abrasive surface prevents surface finish damage, while chemical resistance protects against incidental contact with oils and coolants. The self-supporting rigidity allows tray designs without secondary structural elements.
Retail Display & Point-of-Purchase
For retail environments, 4 mm PP sheet provides the lightest self-standing display backboard — rigid enough to mount on easels or slot into display fixtures without bowing, yet light enough for easy repositioning by store staff. Available in white for direct printing (or pair with our 5mm Corona-treated sheet for high-resolution graphics). See also our Panneaux de signalisation en PP for dedicated signage solutions.
Foire aux questions
Q1: What is a 4mm PP hollow sheet used for?
A 4 mm PP hollow sheet is most commonly used as tray inserts, crate dividers, and inner packaging liners where the board must lie flat under its own weight without a supporting frame. It is the default thickness for electronics component trays, courier box liners, agricultural crate dividers, and automotive parts separators. Its self-supporting rigidity at low weight makes it the cost-optimal choice for flat-panel packaging applications.
Q2: What is the difference between 3mm, 4mm, and 5mm PP corrugated sheets?
3 mm is thin enough to fold into boxes by hand — ideal for foldable packaging where rigidity is less important than formability. 4 mm is the thinnest gauge that is self-supporting — it holds flat without a frame, making it the best choice for inserts, trays, and dividers. 5 mm provides maximum rigidity and is preferred for heavy-duty layer pads, printed signage, and reusable pallets. See our 3mm sheet for folding applications or 5mm sheet for heavy-duty and printing needs.
Q3: Is 4mm PP hollow sheet waterproof?
Yes. Polypropylene’s closed-cell fluted core absorbs zero moisture (water absorption < 0.01 %). Unlike cardboard or solid fibreboard, 4 mm PP hollow sheet does not soften, warp, or degrade when exposed to water, condensation, or high humidity. It performs reliably in refrigerated logistics, outdoor staging, and washdown environments.
Q4: Can I print on a 4mm PP hollow sheet?
Yes, with surface preparation. Standard 4 mm PP sheet accepts screen printing and vinyl overlay without treatment. For high-resolution digital or offset printing , PPBOXY offers Corona-treated 4 mm sheets that raise surface energy from ~30 to 42+ dynes/cm, enabling UV, solvent, and latex ink adhesion. For premium print quality, see our 5mm Corona-treated polypropylene sheet .
Q5: How does 4mm PP hollow sheet compare to cardboard of equivalent thickness?
4 mm PP hollow sheet is waterproof, reusable (50–100+ cycles vs. cardboard’s 1–3 trips), and chemically resistant — all qualities that cardboard lacks. While cardboard has a lower unit price, PP’s reusability delivers a lower per-cycle cost after approximately 5–8 uses. PP also maintains flatness and structural integrity in humid and refrigerated environments where cardboard softens and fails.
Q6: What is the load capacity of a 4mm PP hollow sheet?
A 400 mm × 600 mm panel of 4 mm PP hollow sheet supported at the edges can support approximately 15 kg of uniformly distributed load without visible deflection. Point loads should be distributed using rubber pads or foam inserts to prevent localised flute crushing. For applications requiring higher load capacity, consider our 5mm blue PP corrugated sheet or plastic corrugated layer pads .
Q7: What sizes are available for 4mm PP hollow sheet?
PPBOXY stocks the standard 4×8 ft (1220 × 2440 mm) format with immediate availability. Custom cuts are available from 500 mm × 500 mm up to 2100 mm × 6000 mm . Common pre-cut sizes for electronics, courier, and agricultural applications are listed in the specifications table above. Contact our team for application-specific sizing recommendations.
PP Hollow Sheet 4mm