Faqs

FIBC (Flexible Intermediate Bulk Container) is a large flexible packaging container made of polypropylene woven fabric, designed to carry bulk materials ranging from 500kg to 2000kg, such as chemicals, grains, and minerals. Its core functionality revolves around the unitized transportation concept, fundamentally transforming fragmented packaging models into integrated unit-load systems. By establishing standardized unitized containers, FIBC enables integrated lifting operations via cranes or forklifts, eliminating manual disassembly processes. For example, a truckload of cement traditionally requires hundreds of separate bags for manual handling, whereas FIBC systems accomplish full vehicle loading through single-lift operations, significantly improving efficiency.

Manufactured through polypropylene resin melting, filament drawing, fabric weaving, and sewing processes, FIBC maintains structural integrity under multiple times of rated load impacts during transit. Additional material modifications or structural enhancements enable specialized functions: moisture-proofing for grain storage to prevent mildew, anti-static liners for calcium carbide transportation to avoid explosions, and UV-resistant coatings for outdoor applications.

When empty, FIBCs can be compactly folded, reducing storage space. Reusable variants further enhance cost-effectiveness and environmental sustainability compared to single-use packaging. Serving as "flexible containers," FIBCs standardize bulk cargo handling across scenarios from port terminals to construction sites, resolving efficiency and cost challenges in loose material logistics through mechanized operations.

FIBC (Flexible Intermediate Bulk Container): The formal technical designation under international transportation regulations and quality certifications, systematically defining their flexible structure and intermediate-scale bulk handling characteristics.

Jumbo Bags: Derived from their massive and load-bearing capability, frequently used in maritime bulk cargo transport for commodities like ores and grains. The term "Jumbo" emphasizes their visually imposing design.

Space Bags: Highlights space-saving characteristics. Their collapsible design makes them prevalent in Southeast Asian export regions for optimal container space utilization during bulk cargo shipping.  

Bulk Bags: A generic term in European and American markets, directly denoting their primary application in transporting unpackaged materials (e.g., chemical powders, cereals), emphasizing functional purpose over structural specifics.

Ton Bags: Explicitly references the standardized weight capacity, commonly used in technical documentation and ISO standards to specify industrial-grade load specifications. 

The core distinctions between FIBCs and ordinary woven bags lie in load-bearing capacity, structural design, protective performance, and application scenarios. FIBCs typically have a load capacity range of 0.5–2 tons, with a structure primarily composed of outer polypropylene (PP) woven fabric. High-end variants incorporate inner liners such as polyethylene (PE) film or aluminum-plastic composite materials to enhance sealing properties, alongside integrated lifting loops and reinforced circular straps for compatibility with forklifts or cranes. In contrast, ordinary woven bags have a maximum load capacity of 50 kilograms, relying mainly on single-layer PP woven fabric strength, though some products may incorporate inner liners (e.g., HDPE, EVA) or surface coatings (PE, PVC) for basic moisture resistance.  

Regarding protective performance, FIBCs achieve specialized safeguards through UV-resistant masterbatch additives, aluminum-plastic composite layers, or conductive thread weaving techniques. Ordinary woven bags, however, are constrained by liner integrity and process costs, offering only basic protective capabilities.  

In application scenarios, FIBCs are designed for mechanized bulk material transport (e.g., mineral ores, lithium battery materials, hazardous chemicals), with high customization levels (e.g., internal tension straps for deformation resistance, aluminum foil oxygen barrier for freshness preservation). Ordinary woven bags, while suitable for small-batch chemical additives or construction materials, are incompatible with highly corrosive or precision-sensitive materials due to structural strength and sealing limitations.  

The design philosophies diverge significantly: FIBCs prioritize high load capacity, robust protection, and customizability, whereas ordinary woven bags emphasize cost efficiency, lightweight design, and incremental functional upgrades.

Primary Material: Polypropylene (PP). The core material of FIBCs is polypropylene (PP), accounting for over 90% of the composition. PP, a thermoplastic polymer, exhibits properties such as lightweight high strength, chemical corrosion resistance, and heat resistance (withstands 100℃ sterilization). During production, PP pellets undergo melting, filament extrusion, and weaving into base fabric, which is then cut and stitched into bag structures. To enhance outdoor weathering resistance, UV inhibitors are pre-blended into PP raw materials. High-quality PP pellets must exhibit uniform color, impurity-free composition, and pass tensile strength testing post-extrusion to meet manufacturing standards.  

Functional Additive: Calcium Carbonate Masterbatch. Calcium carbonate masterbatch serves as a cost-reducing filler in FIBCs, typically added at 3%–10%. By partially replacing PP, it lowers production costs while improving base fabric rigidity, dimensional stability, and processing fluidity. For instance, calcium carbonate addition reduces shrinkage and enhances surface smoothness. Modified calcium carbonate variants (e.g., titanium dioxide-coated variants) can reflect UV radiation, synergizing with UV-resistant agents. However, excessive calcium carbonate (e.g., >20%) compromises transparency, toughness, and thermal stability, necessitating coupling agents and lubricant pretreatment to ensure PP compatibility.  

Functional and Aesthetic Enhancement: Color Masterbatch. Color masterbatch, composed of pigments, dispersants, and PP carrier resin, enables FIBC color customization. Pigment concentrations typically range from 20% to 40%, requiring synchronized melting with PP base material to prevent color deviation. In food and chemical industries, masterbatches must comply with non-toxic and heat-resistant standards, while UV-resistant variants require validation via artificial accelerated aging tests.

1. By Shape

(1) Circular: No directional adjustment required during filling; ensures uniform load distribution post-filling, eliminates internal dead zones, and facilitates complete material discharge.  

(2) Square: Highest universality, optimizes space utilization for palletized transport and stacking, with flat surfaces enabling full display of printed content.  

(3) U-shaped: Hybrid structural design combining features of square and circular FIBCs.  

2. By Lifting Configuration  

(1) Top-lift: Lifting loops positioned at the top, suitable for vertical crane hoisting, requiring reinforced connection points between loops and the bag body.  

(2) Bottom-lift: Lifting rings integrated at the base, designed for forklifts or sling-based port cranes to lift from the bottom, commonly used in material dumping or warehouse turnover scenarios.  

(3) Pallet-free: Reinforced base design allows direct ground contact; bottom structure accommodates forklift tines for direct lifting. Ideal for powdered materials prone to caking.  

3.By Functional Features  

(1) Antistatic: Conductive fibers woven into the base fabric, critical for handling petrochemicals or explosive dust-prone materials.  

(2) Moisture-proof: Incorporates PE or aluminum foil inner liners to block moisture permeation, suitable for grains or pharmaceutical raw materials.  

(3) Food-grade: PE-coated or PE Liner provide microbial barriers, compliant with dairy or food additive packaging standards.  

(4) Drainage-type: High-tensile base fabric with enlarged mesh openings to drain excess moisture, optimized for river sand transport.

Material Strength  

Single-use: Typically employs base fabric ≤160g/m² with tensile strength ≥1470N/5cm, prioritizing cost efficiency.  

Reusable: Requires high-strength base fabric (170–210g/m²) with tensile strength ≥2000N/5cm, paired with heat-sealed seams for enhanced durability.  

Functional Design  

Single-use: Simplified structure for short-term transport; may include minimal UV stabilizers.  

Reusable: Enhanced UV resistance (e.g., hindered amine light stabilizers), moisture barriers (PE coatings, added liners), and reinforced stress points.  

Safety Factor  

Single-use: Minimum 5:1 safety factor (e.g., 1-ton rated FIBC withstands 5-ton destructive force).  

Reusable: Mandatory 6:1 safety factor with validated cycle testing (e.g., load retention after repeated use).  

Cost Structure  

Single-use: Lower unit cost but higher long-term expenses due to frequent replacement.  

Reusable: Higher initial investment but lower lifecycle cost through multiple reuse cycles.  

Environmental Impact

Single-use: Generates plastic waste; requires recycling (e.g., reprocessing into plastic pellets) to mitigate pollution.  

Reusable: Aligns with circular economy principles, reducing resource consumption; each reuse cycle lowers carbon footprint by 30%.  

PE Coating  

PE coating involves applying a layer of polyethylene (PE) film to the inner or outer woven fabric surface of an FIBC (Bulk bag/Jumbo bag). It enhances the moisture-proof and waterproof properties of outer layer, preventing water penetration while maintaining a certain level of breathability. It also improves the abrasion resistance and tear resistance of the outer layer, though its sealing performance is inferior to that of a separate liner. With lower cost, it is suitable for basic moisture-proof requirements. It is primarily used for powdered or granular materials with general moisture-proof needs (e.g., fertilizers, animal feed) in environments where strict sealing is not required.  

PE Liner

A PE liner is an independent polyethylene film inner bag placed inside the FIBC. It provides moisture-proof and leak-proof protection, preventing fine particle leakage, but cannot fully block gases or highly permeable substances. It is flexible and conforms easily to the shape of the contents but is susceptible to punctures by sharp objects. With moderate cost and high cost-effectiveness, it is suitable for products requiring leak prevention and moderate barrier properties, such as general chemical raw materials or food additives.  

Aluminum Foil Liner

An aluminum foil liner is composed of multi-layer composite materials, combining the barrier properties of aluminum foil with the heat-sealing properties of PE. It offers high barrier performance, protecting against moisture, oxidation, UV light, oxygen, water vapor, and light. However, aluminum foil is brittle and prone to tearing, requiring protection from the outer woven bag. With higher cost, it is ideal for high-value or sensitive materials. It is primarily used for products with stringent storage requirements, such as food (e.g., coffee, milk powder), pharmaceutical ingredients, or oxidation-prone chemicals.  

Definition and Standards of Safety Factor

Safety factor of an FIBC (bulk bag/jumbo bag) refers to the ratio of ultimate breaking force of bag body and lifting straps to the rated working load, reflecting the safety redundancy of the packaging system.  

- Single-Use Type: Minimum 5:1 safety factor, meaning a 1-ton-rated FIBC must withstand 5 tons of tensile force without failure.  

- Reusable Type: Requires a 6:1 safety factor, with mandatory compliance for hazardous material transportation.  

Load-Bearing Calculation Methods  

The load-bearing capacity of an FIBC is calculated by integrating static loads and dynamic effects:  

1. Static Load Formula  

- Wstatic=Wbag+Wmaterial 

- Where Wbag is the self-weight of the FIBC, and Wmaterial is the net weight of the material.  

2. Dynamic Load Adjustment  

Introduce a dynamic load coefficient kd (1.2–1.5) to account for acceleration effects:  

- Wdynamic = kd x Wstatic

- Example: For a 1-ton material load:  

- Wdynamic = 1.3 x (10kg + 1000kg) = 1313kg  

3. Safety Factor Application  

The final load-bearing capacity must satisfy:  

- Wfinal ≥ SF x Wdynamic  

- Example (5:1 safety factor):  

- Wfinal ≥ 5 x 1313kg = 6565kg

Type A

Type A FIBCs, also known as standard FIBCs, lack antistatic treatment and exhibit high surface resistance (≥10¹² Ω). Prone to electrostatic accumulation, which may generate sparks or discharges.  

Primary applications include: Non-flammable, non-conductive materials (e.g., general plastic pellets, dry construction materials) in low-risk environments with controlled humidity (humidity >50%).  

Type B  

Type B FIBCs, also called specially treated FIBCs, reduce static electricity through surface coatings or structural designs but lack a defined resistance range. Antistatic performance is unstable, posing residual risks.  

Primary applications include: Scenarios without stringent antistatic requirements (e.g., short-term storage of low-risk materials). Additional antistatic measures (e.g., ionizers) must be implemented.  

Type C

Type C FIBCs, known as conductive FIBCs, incorporate conductive fibers or metal threads with surface resistance ≤10⁵ Ω. Type C FIBCs rapidly dissipate static electricity via grounding to eliminate spark risks.  

Primary applications include: High-risk flammable/explosive environments, such as volatile solvents (e.g., ethanol, acetone) or explosive dust-prone materials (e.g., metal powders, sulfur).  Note:  Type C FIBCs must be grounded, and operating environments must comply with explosion-proof standards (e.g., ATEX).  

Type D

Type D FIBCs, termed static dissipative FIBCs, utilize antistatic additives or carbon fibers to achieve surface resistance of 10⁶–10¹¹ Ω. Type D FIBCs gradually release static charges to prevent sudden discharges.  

Primary applications include: General antistatic requirements, such as mildly flammable dusts (e.g., flour, starch), low-volatility chemicals (e.g., plastic pellets, rubber compounds), or scenarios requiring humidity control (humidity >40%).  

Aging Resistance Test Duration Standards

The aging resistance of UV-resistant FIBCs is primarily evaluated through accelerated artificial aging tests. Test duration requirements under different standards are as follows:  

- Chinese National Standard: According to the new GB/T standard General Technical Requirements for Plastic Woven Bags, accelerated aging tests typically use UVB-313 lamps with a test cycle of 144 hours (alternating 8-hour UV exposure and 4-hour condensation cycles). Post-aging retained tensile strength must be ≥50%.  

- International Standards:  

• ISO 4892-3/ASTM G154 specifies a broad test duration range (hundreds to thousands of hours), depending on material type and intended usage. Plastic FIBCs generally require 2,000–4,000 hours of testing.  

• ISO 21898: For FIBC aging resistance, UVB-313 lamps are used, with retained tensile strength required to be ≥50%.  

Methods to Extend Service Life  

1. Material Optimization  

   - Add aging-resistant additives: Incorporate UV stabilizers and antioxidants (0.1%–3% by weight) into polypropylene (PP) or polyethylene (PE) raw materials to significantly enhance UV resistance.  

   - Use color masterbatches with high lightfastness ratings to prevent fading and UV degradation.  

2. Production Process – Sewing Techniques  

   - Employ heavy-duty threads with fine needles or composite stitching techniques to improve seam sealing and aging resistance.  

3. Avoid Direct UV Exposure  

   - Store FIBCs in shaded areas or cover them with UV-blocking tarps during storage to minimize sunlight exposure. 

Core Principles for Matching Base Fabric Grammage Based on Material Characteristics  

1. Matching by Material Weight & Density  

- For FIBCs containing lightweight materials (density <0.8g/cm³), such as grains (wheat, corn), cotton, synthetic fiber products, or foam pellets:  

  160g/m² base fabric is recommended. Low-density materials impose minimal load stress, allowing reduced fabric strength requirements to lower packaging costs and improve handling efficiency.  

- For FIBCs containing high-density materials (density ≥0.8g/cm³), such as polymer pellets (PE/PP), aggregates, feed, cement, or mineral powders:  

  220g/m² base fabric is required. Heavy loads (typically 1-2 tons) demand higher tensile strength and puncture resistance to prevent seam failure or bottom rupture.  

2. Matching by Material Physical Form  

- For smooth/low-abrasion materials (powders, spherical pellets, textiles):  

  160g/m² base fabric suffices due to minimal abrasion and tear propagation risks.  

- For sharp/abrasive materials (crushed ores, construction aggregates, metal chips):  

  220g/m² base fabric is critical. Tightly woven structures with enhanced tear resistance mitigate puncture risks during rough handling.  

3. Matching by Material Chemical Properties  

- For non-corrosive/neutral materials (food-grade products, dry industrial goods):  

  160g/m² base fabric applies. Optional PE coating can be added for moisture barrier requirements.  

- For hygroscopic/corrosive materials (fertilizers, salts, acidic/alkaline powders):  

  220g/m² base fabric is mandatory. Reduced inter-fiber porosity limits moisture ingress, while thicker fabric delays chemical degradation. Additives (e.g., anti-corrosion agents) or laminated fabrics may be required.  

4. Matching by Material Flowability & Filling Method  

- For free-flowing materials requiring rapid discharge (feed pellets, grains, powder coatings):  

  160g/m² base fabric offers superior flexibility for easy bag collapse and cost efficiency.  

- For viscous/blocky materials requiring manual breaking or multi-handling cycles (wet clay, sticky powders):  

  220g/m² base fabric ensures structural integrity under repeated flexing and prevents fine particle leakage through dense weaves.  

5. Matching by Operational Environment  

- Indoor/short-term storage applications:  

  160g/m² base fabric** optimizes cost-effectiveness.  

- Outdoor/long-term exposure or high-frequency reuse scenarios:  

  220g/m² base fabric is essential. Higher PP content and uniform UV stabilizer dispersion enhance weatherability and aging resistance.  

I. Correct loop Attachment and Operation Methods

1.  Inspect loops and equipment: Before lifting, confirm loops are free from wear, tears, or aging. Check hooks, ropes, and other equipment are intact, ensuring their load capacity meets the FIBC payload requirements. If using a forklift, ensure fork tines are smooth and free of burrs to avoid puncturing the bag body.

2.  Loop attachment point selection: Hooks must be attached to the center point of the loops or lifting ropes to ensure even load distribution on both sides, preventing the FIBC from tilting or tipping. For multi-loop designs (e.g., four-loop slings), attach all slings simultaneously to avoid unilateral loading.

3.  Lifting and securing the load: During lifting, slowly raise the FIBC to approximately 40 cm off the ground. Confirm stability before continuing to elevate. When lowering the load, maintain the FIBC body approximately 40 cm above the ground or bin floor. Lower slowly only after stability is confirmed.

4.  Transport and stacking: Utilize pallets for transport where possible to avoid direct hook attachment and swinging during movement. When stacking, position FIBCs upright with spouts facing upwards, avoiding crushing or inversion.

II. Prohibited Operations and Key Considerations

1.  Slanted lifting or unilateral lifting is strictly prohibited: Do not lift at an angle, lift from one side only, or attach only some slings. This causes the FIBC's center of gravity to shift, leading to cargo spillage or sling failure.

2.  Personnel standing in the lifting zone is strictly prohibited: During lifting operations, personnel are strictly forbidden from standing beneath the FIBC or within the surrounding danger zone to prevent injury from accidental falls or impacts.

3.  Avoid friction and collision: During operation, keep clear of sharp objects or rough surfaces to prevent loops from rubbing against or snagging other cargo, which could cause damage or breakage.

4.  Overloading and eccentric loading are strictly prohibited: Strictly adhere to the Maximum Safe Working Load (SWL) marked on the FIBC. Overloading can cause immediate sling failure. Simultaneously, avoid shifting cargo centers of gravity to prevent overloading individual loops.

5.  Rapid lifting/lowering or sudden stops are strictly prohibited: Quick starts, braking, or lifting/lowering generates shock loads (instantaneous forces potentially 2-3 times the rated load). Operate smoothly to avoid inertial forces damaging slings.

6.  Forklift operation prohibitions: When using a forklift, fork tines must not directly contact the bag body. Lift must be via pallets or a dedicated support frame to prevent puncturing the bag.