Woven Polypropylene Sacks and Bags
topic
Woven PP sacks are tubular or flat woven fabric containers (capacity 5–50 kg) for packaging cement, fertiliser, rice, flour, sugar, feed, and industrial minerals, manufactured from flat PP tape yarns (1,200–3,000 dtex, tenacity 40–55 cN/tex) woven at 8–14 tapes/cm in circular or flat looms at 200–500 m/min production rates. Basis weight of 60–120 g/m², tensile strength of 1,500–3,500 N/5cm (EN 29073-3), and drop test performance of 8–12 drops from 1.2 m height without failure (EN 277 Level 2) are key quality parameters. Laminated PP sacks (BOPP film laminated to outer surface, 15–25 µm, gravure-printed in 4–8 colours) provide moisture barrier and high-quality surface printing for retail-facing consumer packaging — moisture vapour transmission rate (MVTR) reduced from 50 g/m²/24h (unlaminated) to 3–8 g/m²/24h (BOPP laminated). Block bottom valve sacks (AD*STAR type, woven PP + BOPP laminate + PE inner liner, 0.8–1.0 kg empty weight) replace paper cement sacks at 80% lower sack weight, 15% higher stacking strength, and complete water resistance versus paper sacks failing at >80% RH. Breathable woven PP (mesh aperture 0.5–2.0 mm, permeability 500–2,000 L/m²/s) for produce packaging (potatoes, onions, citrus) provides ventilation preventing anaerobic respiration and spoilage. Global woven PP sack market exceeds $3.2 billion.
Role
Woven PP sacks are the primary bulk packaging format for the global cement (4 billion tonnes/year), fertiliser (200 million tonnes/year), and food grain (2.8 billion tonnes/year) industries, with tensile strength, moisture barrier, and drop performance directly determining whether packaging integrity is maintained across the multi-modal transport chains linking production sites to end consumers.