Reinforced Kraft Paper for Packing: Production Process, Strength & Applications
Reinforced kraft paper for packing is produced by increasing the proportion of long fibers to enhance its tear resistance. Meanwhile, its tensile strength is tested with dedicated equipment to ensure quality. Reinforced kraft paper has outstanding tear and tensile resistance, making it suitable for applications such as packaging and filter pads.
Definition & Long Fiber for Tear Resistance：reinforced kraft paper for packing
Reinforced kraft paper focuses on “strengthened performance” for packaging. By increasing the ratio of long fibers and optimizing production, it achieves higher tensile and tear resistance than regular kraft paper. It keeps virgin pulp’s eco-friendliness while meeting packaging needs for heavy load, damage prevention, and moisture resistance.
Production Process – 3 Key Links:
- Raw material: Long-fiber softwood pulp ≥85% (pine/spruce, 2.8–4.2mm) creates a dense web-like structure with strong bonding, unlike regular kraft with ≤60% long fiber.
- Beating: Controlled at 25–30°SR to keep fibers intact, avoiding strength loss. Regular kraft uses 35–45°SR, cutting fibers and reducing strength by 30%.
- Papermaking: Long-wire machine with vacuum -0.08MPa and pressing at 200kPa ensures even fiber distribution and strong structural layers, avoiding weak points.
vs. Regular Kraft: Tear Resistance & Long Fiber Advantages
| Performance Dimension | Reinforced Kraft Paper | Regular Kraft Paper | Key Advantage (Reinforced vs. Regular) |
|---|---|---|---|
| Long Fiber Ratio | ≥85% (softwood pulp) | ≤60% (softwood + hardwood pulp) | Stronger fiber bonding, tensile strength improved by 40%+ |
| Tear Strength | Longitudinal ≥18kN/m, Transverse ≥12kN/m | Longitudinal ≤12kN/m, Transverse ≤8kN/m | Tear resistance up by 50%, not easy to rip when carrying heavy loads |
| Wet Strength Stability | Wet tensile ≥12kN/m, no visible deformation after water absorption | Wet tensile ≤6kN/m, softens and deforms after water absorption | Remains durable in damp environments (e.g. wet waste) without breaking |
| Load-Bearing Capacity | Single sheet (80g/m²) supports ≥5kg (even load) | Single sheet (80g/m²) supports ≤2.5kg | Double the load capacity, ideal for heavy-duty packaging (e.g. building materials, hardware parts) |
Application Scenarios: Tear-Resistant for Wet Waste & Heavy-Duty
Wet Waste Packaging
Kitchen waste contains moisture that damages normal kraft. Reinforced kraft resists tearing under 3–5kg load and keeps 10–15μm pores for draining water, reducing leakage during transport. Common specs: 80–120g/m² rolls (500–1200mm), made into vest or flat bags.
Heavy-Duty Packaging
For hardware and construction parts, reinforced kraft provides ≥22kN/m tensile strength, holding 5–8kg without deformation. Its surface resists ≥500 friction cycles, preventing damage. Specs: 120–200g/m² sheets (1000×1500mm) or rolls, also customizable at 200g/m²+.
Filter Pad Packaging
For oily food or cleaned metal parts, reinforced kraft ensures tear resistance and allows drainage of oil/water through fiber pores. It keeps contents dry and safe. Specs: 60–100g/m² sheets (A3/A4 or custom). Food-grade type meets GB 4806.8 for food safety.
Tear Resistance & Heavy-Duty Fit reinforced kraft paper for packing
- Reduce Packaging Loss
Normal kraft has 8–12% breakage, while reinforced kraft cuts it to ≤1.5%, saving 90%+ rework and lowering long-term cost.
- Adapt to Complex Needs
No need for multi-layer reinforcement; a single sheet works for wet waste and heavy loads, boosting efficiency by 30%.
- Eco-Friendly & Durable
Made from 100% virgin long fibers, it fully degrades within 180 days, meets EU/China plastic-ban rules, and supports reuse 2–3 times.
- Flexible Customization
Available in 80–200g/m², 500–2000mm (rolls/sheets). Thickness and size adapt to different needs like waste bags or hardware packaging, avoiding material waste.