Open cement bag instruction

An Open Kraft Cement Bag (also called an open-mouth kraft cement sack) is a heavy-duty, multi-layer paper packaging designed for storing, transporting, and dispensing dry, powdery building materials-primarily cement. It features a fully open top for easy filling and manual closing (sewn, stapled, or heat-sealed), distinct from valve-type sacks that use a narrow spout for automated filling.

open cement bags

open cement bags display filled with cements

- Core Material & Construction of Open Cement Bag
• Base Material: Unbleached brown kraft paper (virgin softwood pulp, e.g., pine) for high tear/burst strength; optional white kraft for premium branding.
• Layer Structure (Multi-Wall):
1. Standard: 3–4 plies (70–90 GSM per layer; total 210–360 GSM).
2. Premium: 4–5 plies + PE film liner (20–25μm) for moisture barrier (critical for cement's hygroscopic nature).
• Key Properties:
1. High tensile strength (resists 50kg load and 1–2m drops).
2. Porous outer layers (release air during filling to prevent bursting).
3. Abrasion resistance (withstands rough handling/stacking).

- Storage & Handling for Open Cement Bag
• Store in dry warehouses (humidity <65%) to avoid moisture damage.
• Keep off concrete floors (use pallets/racks).
• Avoid direct sunlight (degrades paper strength over time).

The Design Features + Customization Options + Performance Specifications (Compliant with GB/T 9774-2020, EN 1086)

A. Design features
• Open Mouth: Full top opening (no valve) for manual filling; closed via:
- Sewn (cotton/polyester thread, traditional).
- Stapled (metal staples, quick).
- Heat-sealed (PE-lined bags, moisture-proof).
• Side Gussets: Expandable pleats (10–11cm width) for volume expansion and stable stacking.
• Printing: Custom flexo/offset printing (1–6 colors) for logos, branding, safety warnings, and specs.
• Color: Natural brown (default) or white (outer layer, premium).

B. Customization Options
• Size: Custom lengths/widths for 20–50kg capacities.
• Lining: PE-coated inner layer or full PE liner (enhanced moisture protection).
• Printing: Branding, QR codes, safety symbols, multilingual instructions.
• Reinforcement: Extra kraft layers or fiber reinforcement for heavy-duty use.

C. Performance Specifications (Compliant with GB/T 9774-2020, EN 1086)
• Drop Test: Survives 1.5m drop onto concrete (filled).
• Stacking Test: Resists a 10-bag stack for 24 hours (no bursting).
• Moisture Resistance: PE-lined bags withstand 80% humidity for 24 hours (no water ingress).
• Burst Strength: ≥250 kPa (50kg bags).