flat-bottom packaging bags for dry-powder kraft paper woven packaging bags

Applicable materials: 
Dry-mix mortar, putty powder (for interior/exterior walls), gypsum powder (building gypsum/high-strength gypsum), cement, quartz sand, dried sand, tile adhesive, grouting material, leak-stopping agent, self-leveling mortar, repair mortar, thermal insulation mortar, waterproof powder, lime powder, and other dry-mix and powdered construction materials.

Key features: 
The outer kraft paper layer delivers a professional, durable finish, enhancing the brand image of dry powder materials and making it ideal for sales through building-materials markets and engineering channels. The multi-layer composite structure offers high strength and excellent stiffness, ensuring that the bag maintains a full, well-shaped profile after filling and remains stable and upright during palletizing. The bag opening is smooth and even, facilitating easy opening and filling, and is compatible with a wide range of automated filling equipment as well as manual production lines. Sealing options are flexible, allowing customers to choose seam sealing, heat sealing, or ultrasonic sealing based on their specific needs. The three-layer construction—kraft paper, woven fabric, and PE film—provides outstanding leak-proof and moisture-resistant performance, effectively keeping dry powder materials dry and free from caking. The bag body is flat and stable when stacked, making it suitable for long-distance transportation and warehouse storage. Optional additives such as anti-aging agents and UV stabilizers further enhance durability, preventing brittleness and color fading when stored outdoors or in warehouses. High-quality printing ensures clear, eye-catching product information that meets building-materials packaging standards. Overall, the solution offers moderate cost-effectiveness.

Core Advantages: 
Moisture- and leak-proof, tensile-strength and puncture-resistant, with a professional, durable kraft-paper appearance; multi-layer composite structure for high strength; alkali-resistant and corrosion-proof; compatible with various filling methods; easy to seal and easy to palletize.

Material and Craftsmanship: 
The base material consists of a woven fabric made from PP (polypropylene) or HDPE (high-density polyethylene), laminated on the exterior with high-grammage kraft paper (available in white, yellow, or natural colors), and internally combined with a PE barrier film or a laminated layer, forming a three-layer composite structure of “kraft paper + woven fabric + PE film.” The bag style is a flat pouch, with bottom options including sewn-in bottom (requiring sealing strips or liner paper), heat-sealed bottom, or ultrasonically sealed bottom. Printing is carried out using 2- to 7-color gravure color printing with lamination, resulting in exquisite patterns and vibrant colors; the kraft paper base imparts a professional, durable texture, while the laminated layer offers water-resistant and wear-resistant properties, making it ideal for showcasing building-material brand image and product information.

Sealing method: 
After filling, sealing can be performed according to customer requirements using a sewing machine for stitched sealing (requiring sealing strips or liner paper), heat sealing (requiring an inner bag), ultrasonic sealing (no needle holes, with excellent leak-proof performance), or tie-sealing (suitable for small packages).

Applicable filling method: 
Compatible with screw fillers, impeller fillers, pneumatic fillers, gravity fillers, and manual filling (for semi-automatic or small-batch production lines).

Tensile strength: 
Testing has confirmed that the tensile strength reaches ≥700 N/50 mm, fully meeting the requirements for stacking loads of 10 to 50 kg and for long-distance transportation.

Moisture resistance: 
The water vapor transmission rate is reduced by more than 90% in a three-layer structure consisting of kraft paper, woven fabric, and PE film, effectively preventing dry powder materials from absorbing moisture, caking, hardening, and losing efficacy, with a shelf life of over six months. An optional aluminum foil layer can further reduce the water vapor transmission rate by more than 98%, making it suitable for specialized dry powder materials with extremely stringent moisture-barrier requirements.

Corrosion resistance grade: 
Meeting five-star standards, this packaging exhibits exceptional resistance to cement’s alkaline components, gypsum’s acidic components, additives, and various construction chemicals, ensuring that it remains intact—without softening, cracking, or leaking—even after prolonged contact with dry powder materials.

Packaging drop test: 
Under a 50 kg load condition, following a 1.2-meter free-fall test, the product remained intact and showed no powder leakage after being dropped from all six sides.

Printing standards: 
Solvent-resistant inks are used, offering both alkali resistance and abrasion resistance, fully complying with relevant standards for labeling on building-material packaging. Barcode and QR-code scanning and recognition rates reach 100%, supporting product traceability, access to usage instructions, and anti-counterfeiting verification.

Customization Scope: 
Supports multi-color overprinting, enabling the printing of brand logos, product names, net content, implementation standard numbers, product descriptions, application instructions, mixing ratio recommendations, precautions, production date and batch number (with a designated area for inkjet coding), shelf life, as well as the name and address of the manufacturer. Additional features include warning labels such as “Moisture-Proof,” “Drop-Resistant,” “Keep Away from Acids and Alkalis,” and “Use Promptly After Opening,” along with spaces reserved for barcodes, QR codes, anti-counterfeiting label areas, measurement markings (e.g., 20 kg, 25 kg, 40 kg scale lines), environmental recycling symbols, and transparent windows that display the contents to enhance customer trust.

Environmental Compliance: 
The product is manufactured using virgin materials; the kraft paper layer is partially biodegradable, while the woven fabric and barrier layer are recyclable. We can provide export-related certifications to meet the market access requirements of overseas markets.

Key features: 
The outer kraft paper layer delivers a professional, durable finish, enhancing the brand image of dry powder materials and making it ideal for sales through building-materials markets and engineering channels. The multi-layer composite structure offers high strength and excellent stiffness, ensuring that the bag maintains a full, well-shaped profile after filling and remains stable and upright during palletizing. The bag opening is smooth and even, facilitating easy opening and filling, and it is compatible with a wide range of automated filling equipment as well as manual production lines. Sealing options are flexible, allowing customers to choose between stitched sealing, heat sealing, or ultrasonic sealing based on their specific needs. The three-layer construction—kraft paper, woven fabric, and PE film—provides outstanding leak-proof and moisture-resistant performance, effectively keeping dry powder materials dry and free from caking. The bag body is flat and stable when stacked, making it suitable for long-distance transportation and warehouse storage. Optional additives such as anti-aging agents and UV stabilizers further enhance durability, preventing brittleness and color fading when stored outdoors or in warehouses. The printing is exquisite, with clear and prominent product information that meets building-materials packaging standards. Overall, the cost is moderate; compared with all-kraft-paper bags, this design offers higher strength at a lower cost, making it ideal for large-volume procurement.

Packaging specifications: 
All specifications can be customized to meet customer requirements, including bag fill weight (commonly ranging from 10 kg to 50 kg, with typical sizes of 10 kg, 15 kg, 20 kg, 25 kg, 40 kg, and 50 kg), bag dimensions (length × width), sealing method (sewn bottom/heat-sealed bottom/ultrasonic sealing), inner-bag material (PE barrier film or aluminum foil), number of inner-bag layers (single-layer or double-layer), kraft paper basis weight (commonly 80 g/m² to 120 g/m²), and printing area (single-sided, double-sided, or full-color), among others.

Applicable to: 
This product is suitable for dry-mix mortar manufacturers, putty powder plants, gypsum powder processing enterprises, cement and quartz sand producers, tile adhesive manufacturers, leak-stopping and self-leveling material producers, grouting sealant manufacturers, building-material packaging wholesalers, and building-material export traders.

Price and Minimum Order Quantity: 
Specific pricing and minimum order quantities are negotiable. Please feel free to call or write for a quotation.