Automatic filling, full-color printed, square-bottom, valve‑mouth gypsum woven packaging bag

I. Product Introduction (Woven Bags)

This product is Square-bottom valve bag (glue-sealed bag) , specially for Gypsum-based self-leveling and pavement repair materials Dry-mix mortar formulation. The bag is constructed from a composite of PP woven fabric and PE film, with monochrome printing that clearly displays the product name, key selling points, and net content. This packaging bag features… Automatic filling at the valve port, leak-proof and dust-proof, stable palletizing. With comparable performance, it is an economical and practical packaging solution for dry-mix construction material companies.

II. Applicable to (Applicable Scenarios)

Packaging Gypsum-based self-leveling material 、 Rapid Pavement Repair Mortar

Fully automatic valve‑mouth filling for dry mortar production lines

Warehouse stacking, long-distance transportation, and retail sales at building materials markets

Construction sites—such as road emergency repairs and flooring projects—that have requirements for packaging efficiency and moisture protection.

III. Applicable Materials

Gypsum-based self-leveling mortar

Rapid pavement repair materials (cement-based or gypsum-based)

Self-leveling leveling mortar

High-strength grouting material

Other dry-powder-based construction repair materials

IV. Core Advantages

Product level (in-bag material):

Green and Energy-Efficient: Environmentally friendly formulation, compliant with green building material standards.

Precise leveling: excellent fluidity and self-leveling performance.

Quick-drying and crack-resistant: rapid setting, high early strength, and effective crack suppression.

Efficient and Fast: Simple construction, significantly shortening the project timeline.

At the packaging bag level:

Automatic filling with a square-bottom valve: compatible with automated production lines, offering high filling efficiency.

Leak-proof and dustproof: self-sealing valve opening + pinhole-free sealed bottom + PE inner liner lamination, completely preventing powder leakage.

Monochrome printing – economy option: 1–2 colors, low plate fees, and an affordable unit price.

Square-bottom stacking stability: After filling, the product forms a brick‑shaped cuboid, allowing for neat, stable stacking without toppling.

High Strength and Break Resistance: The PP woven fabric boasts high tensile strength and can safely support a load of 25 kg.

Moisture-proof and freshness-preserving: The PE film layer acts as a barrier to water vapor, preventing gypsum-based materials from absorbing moisture and caking.

V. Automatic Filling with Square Bottom and Valve Opening

Valve port structure : One side of the bag body is equipped with a filling valve port (typically an upper valve port).

Filling equipment : Compatible with screw‑type valve‑mouth packaging machines or pneumatic filling machines

Filling efficiency : Single machine 300 ~ 600 bags/hour, 800 on the fully automatic line ~ 1,200 bags/hour

Automatic closure Filling pressure seals the inner side of the valve opening, eliminating the need for bag sealing.

VI. Leak-Proof and Dust-Proof Design Details

Self-sealing valve port : After filling, the material pressure presses the inner side of the valve seat tightly, creating a natural seal.

PE inner membrane composite The intermediate-layer PE film is thermally laminated to seal the woven gaps, effectively preventing fine powder from leaking out.

Hot-melt adhesive bottom coating : Bottom seam with no pinholes, offering far superior sealing compared to sewn-bottom bags.

Laminated sealing : The outer coating further seals the pores of the woven fabric.

Optional microporous venting For aerated powder materials, micro‑perforation can be performed to equalize air pressure while minimizing dust emission.

VII. Monochrome Printing – Economy Model

Number of printing colors : 1–2 colors (typically the brand logo, product name, net content, and key selling points)

Publication fee cost : Monochrome versions cost approximately 200–500 yuan; bulk orders may qualify for a discount.

Unit price advantage Compared to full-color customization, the unit price of monochrome models can be reduced by 30% to 50%.

Customized content : Can print the company name, product name, net content (25 kg), eco-friendly and energy-saving selling points, and recycling symbols.

8. Stable Stacking on Square Bases

Post-filling form : The powdered material naturally forms a quadrangular (brick-shaped) structure inside the bag, with a flat bottom.

Independence : Can stand independently without leaning against a wall

Stacking performance : Square and well‑shaped; stackable up to 8–10 layers without toppling.

Warehousing and Transportation : Space-saving, suitable for container and pallet transport

9. Comparison between Square-Bottom Valve Bags and Flat Bags (Open-Top Bags/Sewn-Bottom Bags)

Bottom shape : Square-bottom valve bags are square and flat, sealed with hot-melt adhesive; flat bags are sealed with stitched seams, with visible thread ends protruding.

Dustproof sealing performance : Square-bottom valve bags are superior (no pinholes); flat bags are inferior (many seam pinholes, prone to powder leakage).

Filling efficiency : Square-bottom valve bags are very tall and can be fully automatically filled with a tube; flat-bottom bags are lower and require manual or semi-automatic handling.

Palletizing stability : Square-bottom valve pouches are superior (self-standing cubic shape); flat pouches are standard (round bottom makes them easy to roll).

Automated adaptation : Square-bottom valve bags are perfectly compatible with fully automated packaging lines; flat bags require manual intervention or equipment modifications.

Cost : The square-bottom valve bag is slightly taller; the flat bag is lower.

Main uses : Square-bottom valve bags are used for cement, mortar, self-leveling compounds, and chemical powders; flat bags are used for ores, aggregates, and low-value bulk materials.

X. Material and Craftsmanship

10.1 Structural Composition

Outer layer: Color-printed PP woven fabric (single-color printing)

Middle layer: PE film (moisture-barrier layer, thickness 5–12 μm)

Inner layer: PP woven base fabric (basis weight ≥ 65 g/m²)

Bag Type: Square-bottom valve bag (glue-sealed bottom, top valve opening)

10.2 Production Process Flow

Drawing → Weaving → Composite Molding → Gravure Printing → Valve Mouth Forming → Glue‑Back Bag Making → Hot‑Melt Adhesive Bottom Sealing → Finished‑Product Inspection

XI. Tensile Strength

Longitudinal tensile strength : ≥450 N/50mm (in accordance with GB/T 8946)

Zonal tensile strength : ≥450 N/50mm

Elongation at break : 15%~30%

Peel strength (composite layer) : ≥3.0 N/15mm

Safe load capacity : 25kg

XII. Moisture-Proof Rating

Water vapor transmission rate (WVTR) : ≤15 g/(m²·24h) (GB/T 1037)

Moisture-proof effect Under conditions of relative humidity ≤80%, the material can be guaranteed not to absorb moisture or cake within 3 months.

Upgrade Options : The PE film can be thickened to 80 μm, reducing the water vapor transmission rate to ≤5 g/(m²·24h).

13. Packaging Drop Test

Test Standard : GB/T 4857.5

Drop height : 1.2 meters

Fall order : Elevation → Plan → Side View

Criteria for Determination : The bag is undamaged, and the contents are free of spillage.

XIV. Applicable Filling Method

Filling equipment : Valve‑port‑specific packaging machines (screw‑type, pneumatic‑conveying, impeller‑type)

Filling process : Automatic bagging → Valve‑mouth docking → Automatic metered filling → Valve‑mouth self‑sealing → Conveying to the downstream line

Auxiliary equipment : Can be equipped with an automatic palletizer and a stretch wrapper.

15. Packaging Specifications

Applicable Net Content : 25 kg (as indicated in the image)

Common size (25 kg square-bottom valve bag) : Width 40 cm × Length 50 cm × Bottom fold 13 cm (for reference)

Bag type : Square-bottom valve bag (top valve opening)

Valve port type : Flanged type / Cylindrical type / Membrane type

16. Scope of Customization

Printed content Product name (pavement repair material, gypsum-based self-leveling compound), brand (Leader), key selling points (green and energy-saving, precise leveling, fast-drying and crack-resistant, highly efficient and quick), net content, QR code.

Net Content Specification : Customizable from 15 to 50 kg

Bag body dimensions : Customized according to material density

Material : PP basis weight (45 ~ 80 g/m²), PE film thickness (5 ~ 80 μm)

Other features : Anti-slip embossed texture, one-way vent valve, easy-tear notch

Minimum order quantity Custom-printed bags typically require a minimum order of 5,000 to 10,000 units (some manufacturers may accept orders as low as 1,000 units).

XVII. Environmental Compliance

Packaging Standards : Complies with GB/T 8946-2013 “General Technical Requirements for Plastic Woven Bags”

Ink Safety : Benzene- and ketone-free, compliant with GB 9685

Recyclability : Both PP and PE are recyclable materials.

Export Compliance : Meets the requirements of EU Regulation 10/2011 and the RoHS Directive.

18. Price and Minimum Order Quantity

Price reference (monochrome printing, 25 kg square-bottom valve bags)

Purchase quantity: 1,000 ~ 4,999 items: 0.8 ~ 1.3 yuan per piece (plate fee extra)

Purchase quantity: 5,000 ~ 19,999 items: 0.7 ~ 1.0 yuan per piece (plate fee may be waived)

Purchase quantity: 20,000 ~ 49,999 items: 0.6 ~ 0.9 yuan per piece

For purchase quantities of 50,000 units or more: RMB 0.5–0.8 per unit.

The laminated moisture-proof version adds approximately RMB 0.1–0.3 per unit; thicker PE film or the addition of an air-release valve incurs further costs.

Minimum order quantity

Negotiable

XIX. Applicable Parties (Procuring Entity)

Manufacturer of gypsum-based self-leveling and pavement repair materials

Dry-mix mortar enterprise

Building materials packaging traders and export enterprises

Brand owners requiring OEM contract manufacturing and packaging services