What Is PP Woven Fabric?
PP woven fabric is a textile material made from interlaced polypropylene flat tapes (yarns) produced on circular looms. It forms the structural body of PP woven cement bags, providing exceptional strength-to-weight ratio, moisture resistance, and durability.
Polypropylene is a thermoplastic polymer derived from petroleum. When extruded into flat tapes and woven into fabric, it creates one of the most cost-effective and durable packaging materials available for heavy-duty industrial use.
PP Fabric Production Process
- PP Granule Extrusion — PP granules + additives → molten polymer → flat film
- Slitting — Film is slit into narrow strips (2–3mm wide)
- Stretching — Strips are stretched 5–7× for orientation → high-strength flat tapes
- Winding — Tapes are wound onto bobbins for loom use
- Weaving — Circular looms interlace warp and weft tapes → tubular fabric
- Rolling — Finished fabric is wound onto rolls
Types of PP Woven Fabric
By Construction
| Type | Description | GSM | Best For |
|---|---|---|---|
| Standard Woven | Basic interlaced tape fabric | 55–80 GSM | Budget bags, dry climates |
| Dense Woven | Tighter weave, higher tape count | 80–120 GSM | Heavy-duty, premium bags |
| Laminated Woven | PE/BOPP film bonded to surface | +15–40 GSM | Moisture-sensitive markets |
| Coated Woven | PP coating on surface | +10–20 GSM | Printed bags, clean surface |
By Tape Type
- Flat Tape — Standard, most common (2–3mm wide, 20–40 micron thick)
- Fibrillated Tape — Slit tape for net-like structure; lighter but weaker
- Multifilament — Round yarn; softer, less common in cement bags
By Color
- Natural (translucent) — Standard, lowest cost
- White — TiO₂ added, better printing base, +5–10% cost
- Colored — Masterbatch added (green, blue, etc.), +10–15% cost
Key Specifications
| Property | Typical Range | Test Standard |
|---|---|---|
| Fabric Weight | 55–120 GSM | ISO 3801 |
| Mesh Count | 10×10 to 14×14 per 10cm | EN ISO 7211 |
| Tensile Strength (Warp) | 30–80 kN/m | ISO 13934 |
| Tensile Strength (Weft) | 25–60 kN/m | ISO 13934 |
| Elongation at Break | 15–25% | ISO 13934 |
| Denier (Tape) | 600–1200 denier | — |
| UV Resistance | 200–500 hours | ASTM D4329 |
Understanding Mesh Density
Mesh count (e.g., 10×10) means the number of tapes per 10cm in warp × weft directions:
- 10×10 — Standard mesh, economical
- 12×10 — Denser warp, better strength in bag length direction
- 14×14 — High density, premium strength, suitable for lamination
Higher mesh = stronger fabric = more material = higher cost.
Fabric Weight Guide for Cement Bags
| Bag Capacity | Recommended GSM | Mesh | With Lamination |
|---|---|---|---|
| 25 kg | 55–65 GSM | 10×10 | 70–90 GSM |
| 40 kg | 65–80 GSM | 12×10 | 80–110 GSM |
| 50 kg | 75–100 GSM | 12×10 or 14×14 | 90–130 GSM |
| Heavy-duty 50 kg | 100–120 GSM | 14×14 | 115–150 GSM |
Cost Analysis
Raw Material Costs
| Component | Cost Range | Notes |
|---|---|---|
| PP Granules | $0.80–$1.20/kg | Main raw material, tracks oil prices |
| Masterbatch (white) | $1.50–$3.00/kg | For white/colored fabric |
| UV Stabilizer | $3.00–$6.00/kg | Protects against sun degradation |
| CaCO₃ Filler | $0.10–$0.20/kg | Reduces cost, reduces strength |
Cost Per Bag (Fabric Only)
| Bag Type | Fabric Weight | Cost per Bag |
|---|---|---|
| 25 kg (60 GSM) | ~45g | $0.04–$0.06 |
| 50 kg (80 GSM) | ~90g | $0.07–$0.11 |
| 50 kg laminated (100 GSM) | ~110g | $0.09–$0.14 |
| 50 kg heavy-duty (120 GSM) | ~130g | $0.10–$0.16 |
PP Granule Quality Matters
- Virgin PP — Best tape strength, consistent quality ($1.00–$1.20/kg)
- Reproc (Reprocessed) — 10–20% recycled; good quality, lower cost ($0.85–$1.00/kg)
- High-Fill — 20–40% CaCO₃ filler; lowest cost but weaker ($0.60–$0.85/kg)
- Recycled — 50–100% recycled; variable quality, cheapest ($0.50–$0.80/kg)
Warning: Using too much filler or recycled content reduces tape strength and can cause bag failures. Limit filler to 10–20% for cement bags.
Quality Control Tests
Essential tests for PP woven cement bag fabric:
- Tensile Strength Test — Pull fabric strip until breakage; measure force (kN/m)
- Elongation Test — Measure stretch percentage at breaking point
- Drop Test — Fill bag with 50kg, drop from 1.5m onto concrete (pass = no breakage)
- Water Resistance — Cobb test for laminated fabric (water absorption in g/m²)
- UV Resistance — Expose fabric to UV for 200+ hours; measure strength retention
- Seam Strength — Test sewn seam strength (should exceed 85% of fabric strength)
Environmental Considerations
PP Woven Bag Environmental Impact
- Recyclable — PP is type 5 plastic, fully recyclable
- Reusable — Many cement bags are reused for other purposes
- Carbon footprint — Lower than paper on a strength-normalized basis
- Ocean pollution risk — Non-biodegradable; responsible disposal required
Sustainability Trends
- Recycled PP content increasing (up to 30% in some markets)
- Bio-based PP development (from renewable sources)
- Bag collection and recycling programs expanding in Asia and Africa
- Some markets shifting from PP to biodegradable paper alternatives
Frequently Asked Questions
What is the most common GSM for cement bags? 70–80 GSM is the most common for standard 50kg cement bags in Asia and Africa. European markets typically use 90–120 GSM for heavier-duty requirements.
How much PP granule is needed per bag? A standard 50kg cement bag at 80 GSM uses approximately 80–100 grams of PP granules. A factory producing 1 million bags/month needs approximately 80–100 tons of PP granules monthly.
Does oil price affect PP fabric cost? Yes, significantly. PP is a petroleum derivative. When crude oil rises by $10/barrel, PP granule prices typically increase by $50–$80/ton, raising per-bag cost by $0.005–$0.008.
Can I use the same fabric for cement and fertilizer bags? Yes. The same PP woven fabric works for cement, fertilizer, grain, and other dry bulk materials. You may adjust GSM and mesh density based on product weight and handling requirements.
Learn about circular looms that weave this fabric in our Circular Loom Guide or explore PP woven machines in the machine directory.