Polypropylene
Polypropylene Film & Sheet
Polypropylene combines low density, chemical resistance, and live-hinge fatigue performance in a substrate that prints, folds, and converts cleanly. K&R stocks corona-treated print-grade polypropylene for binders, packaging, and signage, plus untreated grades for industrial fabrication.
At a glance
- Specific gravity
- 0.90 – 0.91
- Service temp
- Up to 200°F / 93°C
- Tensile strength (yield)
- 4,500 – 5,500 psi
- Stock gauges
- .010, .015, .020, .030 (treated); .020 – .250 (natural)
Applications
- Binders, folders, presentation covers, and tabbed dividers
- Live-hinge boxes, enclosures, and clamshells
- Packaging: trays, lids, blister packs
- Signage: indoor and outdoor printed graphics
- Automotive interior components
- Food-contact applications (FDA-compliant grades)
- Industrial fabrication: chemical-resistant parts
Features & benefits
- Low specific gravity (0.90) — highest yield per pound of common substrates.
- Excellent chemical resistance to acids, bases, alcohols, and most solvents.
- Outstanding live-hinge fatigue resistance — bends repeatedly without cracking.
- Corona-treated grades print cleanly via toner, indigo, inkjet, screen, and offset.
- Higher service temperature than polyethylene (continuous to 200°F).
- FDA-compliant grades available for direct food contact.
- Cleanly fabricates by die-cutting, scoring, folding, and ultrasonic welding.
Print & process compatibility
| Method | Compatibility | Notes |
|---|---|---|
| Toner / Laser | ✓ treated | |
| HP Indigo | ✓ treated | |
| UV Inkjet | ✓ treated | |
| Solvent Inkjet | ✓ treated | |
| Screen | ✓ treated | |
| Offset | ✓ treated |
Available surfaces, finishes & gauges
| Surface / finish | Description | Stock gauges |
|---|---|---|
| Corona-Treated Matte | Print-grade polypropylene with corona surface treatment for toner, indigo, inkjet, screen, and offset adhesion. | .010, .015, .020, .030 |
| Natural / Translucent | Untreated grade for fabrication and bonding applications. | .020 – .250 |
| Color PP | Solid color stock and PMS-matched custom colors available. | Custom |
| Live-Hinge Grade | Engineered for repeated folding without crack propagation. | Custom |
Typical properties
Typical of average lots. Job-specific qualification recommended for production runs — request a sample.
| Property | Typical value | Test method |
|---|---|---|
| Physical | ||
| Specific gravity | 0.90 – 0.91 | ASTM D 792 |
| Water absorption (24 hr) | <0.02 % | ASTM D 570 |
| Hardness, Rockwell R | 85 – 110 | ASTM D 785 |
| Mechanical | ||
| Tensile strength at yield | 4,500 – 5,500 psi | ASTM D 638 |
| Tensile elongation at break | 100 – 600 % | ASTM D 638 |
| Flexural modulus | 200,000 – 250,000 psi | ASTM D 790 |
| Izod impact (notched, 73°F) | 0.5 – 2.0 ft-lb/in | ASTM D 256 |
| Thermal | ||
| Continuous service temperature | Up to 200°F (93°C) | — |
| Vicat softening temperature | 300°F (150°C) | ASTM D 1525 |
| Heat deflection temp. (66 psi) | 210°F (99°C) | ASTM D 648 |
| Melt flow rate | 2 – 12 g/10 min (varies by grade) | ASTM D 1238 |
| Print / surface | ||
| Dyne level (corona-treated) | ≥ 38 dynes/cm | ASTM D 2578 |
| Recommended treatment lifespan | Print within 30 days of treatment | — |
Fabrication & converting
Corona-treated grades should be printed within 30 days of treatment for best dyne retention. Die-cuts, scores, folds, and ultrasonic welds clean. Live-hinge grade engineered for repeated folding without crack propagation.