Leakproof multi-layer composite flexitank
By employing a double-layer structure and hot melt adhesive bonding technology, the problems of leakage and insufficient mechanical strength in the transportation of ultrafine powders have been solved, achieving a leak-proof and durable container bag design suitable for the packaging and transportation of powder materials.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-08
- Publication Date
- 2026-06-26
AI Technical Summary
In existing technologies, traditional single-layer woven bags and ordinary composite bags have problems of leakage and insufficient mechanical strength when transporting ultrafine powders below 200 mesh. In particular, the risk of leakage at the seams of the bag body is prominent under repeated filling and unloading conditions, and the problem of synergistic optimization between leakage prevention of ultrafine powders and mechanical strength of the bag body has not been effectively solved.
It adopts a double-layer structure. The inner layer is a dense barrier layer formed by biaxially stretched LLDPE film, and the outer layer is a high-strength PP woven fabric with a composite wear-resistant coating. The entire surface is bonded by hot melt adhesive, and a microporous mesh structure is formed by reactive hot melt adhesive to enhance the interlayer bonding strength. Multiple sleeve structures are set at the top to disperse the lifting stress.
It achieves zero leakage of 200-mesh ultrafine powder, improves tensile strength and interlayer bonding strength, and ensures leak-proof and high durability throughout the entire transportation cycle.
Smart Images
Figure CN224410236U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of leak-proof container bag technology, and in particular to a leak-proof multi-layer composite container bag. Background Technology
[0002] In the field of powder material transportation, FIBCs (Flexible Intermediate Bulk Containers) are widely used for packaging and transporting various powders and granules. For ultrafine powders below 200 mesh, such as nanomaterials and fine chemicals, traditional single-layer woven bags suffer from leakage due to fiber gaps, resulting in material loss and environmental pollution. While ordinary composite bags improve leak-proofness, they are prone to peeling failure due to insufficient interlayer bonding, and the outer layer's abrasion resistance and tensile strength are insufficient for heavy-duty packaging requirements. Current technologies have not effectively solved the problem of synergistic optimization between leak-proofing of ultrafine powders and the mechanical strength of the bag body, especially under repeated filling and unloading conditions, where the risk of leakage at the bag seams is more prominent. Therefore, there is an urgent need to develop a composite FIBC structure that combines the sealing performance of ultrafine powders, high load-bearing capacity, and durability. Utility Model Content
[0003] The purpose of this invention is to provide a leak-proof multi-layer composite container bag.
[0004] The innovation of this utility model lies in the use of a biaxially oriented LLDPE film inner layer that can block the leakage of ultrafine powder below 200 mesh, combined with a high-strength PP woven fabric outer layer to ensure tensile strength, and the full surface composite is achieved by quantitative hot melt adhesive coating, eliminating interlayer separation and seam leakage.
[0005] To achieve the above-mentioned utility model objectives, the technical solution of this utility model is as follows: A leak-proof multi-layer composite container bag, comprising a bag body, wherein the top of the bag body is provided with an inlet and the bottom with an outlet, characterized in that the bag body has a double-layer structure, the double-layer structure comprising an inner layer structure in contact with the powder particles inside the bag and an outer layer structure in contact with the outside, wherein the inner layer structure is a dense barrier layer formed by biaxial stretching of a linear low-density polyethylene film with a thickness of 0.08-0.15mm, and its surface pore size is ≤50μm; the outer layer structure is a wear-resistant coating composited on the surface of a polypropylene woven fabric substrate, the substrate basis weight is ≥150g / m², the warp tensile strength is ≥80kN / m, and the weft tensile strength is ≥70kN / m; the inner layer structure and the outer layer structure are fully composited by a hot melt adhesive bonding layer, the hot melt adhesive coating amount is 8-12g / m², and the adhesive peel strength is ≥6N / cm.
[0006] Furthermore, the inner layer structure is made by co-extrusion blow molding process and includes a three-layer composite structure, with the middle layer being maleic anhydride grafted modified linear low-density polyethylene, and the inner and outer outer layers being LLDPE with a melt index of 2-5 g / 10 min.
[0007] Furthermore, the wear-resistant coating of the outer structure is a polyurethane-silicone composite coating with a thickness of 0.03-0.05 mm.
[0008] Furthermore, the hot melt adhesive layer is made of reactive polyolefin hot melt adhesive, which forms a microporous network structure after curing.
[0009] Furthermore, the top of the bag is provided with multiple sets of sleeve structures for lifting.
[0010] The beneficial effects of this utility model are: the biaxially stretched LLDPE inner layer enables zero leakage of 200-mesh ultrafine powder; the high-strength PP woven fabric outer layer improves tensile strength; the addition of a fixed-quantity hot melt adhesive layer improves interlayer bonding strength; and the addition of multiple sets of sleeve tube structures at the top disperses hoisting stress, ultimately achieving the goal of preventing leakage and high durability throughout the entire transportation cycle. Attached Figure Description
[0011] Figure 1 This is a schematic diagram of the overall structure of this utility model.
[0012] Figure 2 This is a schematic diagram of the inner and outer layers of the bag of this utility model.
[0013] In the picture:
[0014] 1. Bag body; 2. Inner layer structure; 3. Outer layer structure; 4. Hot melt adhesive layer; 5. Wear-resistant coating. Detailed Implementation
[0015] The technical solutions in the embodiments of this utility model will now be clearly and completely described with reference to the accompanying drawings.
[0016] Example 1: As Figure 1 , 2As shown, a leak-proof multi-layer composite container bag includes a bag body 1, with an inlet at the top and an outlet at the bottom. The bag body 1 has a double-layer structure, comprising an inner layer 2 that contacts the powder particles inside the bag body 1 and an outer layer 3 that contacts the outside. The inner layer 2 is a dense barrier layer formed by biaxial stretching of a linear low-density polyethylene film with a thickness of 0.08-0.15mm, and its surface pore size is ≤50μm. The outer layer 3 is a wear-resistant coating composited on the surface of a polypropylene woven fabric substrate, with a substrate weight ≥150g / m², a warp tensile strength ≥80kN / m, and a weft tensile strength ≥70kN / m. The inner layer 2 and the outer layer 3 are fully composited by a hot melt adhesive layer 4, with a hot melt adhesive coating amount of 8-12g / m² and an adhesive peel strength ≥6N / cm. The inner structure is made by co-extrusion blow molding and consists of a three-layer composite structure. The middle layer 21 is maleic anhydride-grafted modified linear low-density polyethylene, and the inner and outer outer layers 22 are LLDPE with a melt index of 2-5 g / 10 min. The wear-resistant coating 5 of the outer structure 3 is a polyurethane-silicone composite coating with a thickness of 0.03-0.05 mm. The hot melt adhesive layer 4 uses reactive polyolefin hot melt adhesive, which forms a microporous mesh structure after curing. The top of the bag body 1 has multiple sets of sleeve structures for lifting.
[0017] The working principle of this invention is as follows: The capillary resistance effect of the biaxially stretched LLDPE inner layer physically intercepts ultrafine powders smaller than 200 mesh; the maleic anhydride graft layer in the co-extrusion blow molding process enhances the film's cohesive strength through polar anchoring, preventing delamination and leakage; a high-basis-weight PP woven fabric constructs a three-dimensional load-bearing skeleton, which dissipates transport impact through a viscoelastic friction interface formed by a polyurethane-silicone coating; the reactive hot melt adhesive cures to form a microporous network cross-linked structure, achieving seamless interlayer sealing and releasing bending stress through microporous deformation; multiple sets of sleeve tubes at the top construct a truss-type force flow transmission system, reducing local stress peaks during hoisting. In the workflow: during the loading stage, the inner layer prevents particle leakage; during hoisting, the outer layer resists tensile stress and the coating is wear-resistant; during stacking, the microporous structure buffers static pressure; and during unloading, the LLDPE layer resists tearing, achieving full-cycle leak prevention and long-term durability for ultrafine powders.
[0018] In summary, the described embodiments are merely some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without inventive effort are within the scope of protection of this utility model.
Claims
1. A leak-proof multi-layer composite container bag, comprising a bag body, wherein the top of the bag body is provided with an inlet and the bottom with an outlet, characterized in that, The bag has a double-layer structure, comprising an inner layer that contacts the powder particles inside the bag and an outer layer that contacts the outside. The inner layer is a dense barrier layer formed by biaxial stretching of a linear low-density polyethylene film with a thickness of 0.08-0.15 mm and a surface pore size ≤50 μm. The outer layer is a wear-resistant coating on a polypropylene woven fabric substrate with a substrate weight ≥150 g / m², a warp tensile strength ≥80 kN / m, and a weft tensile strength ≥70 kN / m. The inner and outer layers are fully bonded together by a hot melt adhesive layer with a coating amount of 8-12 g / m² and an adhesive peel strength ≥6 N / cm.
2. The leak-proof multi-layer composite container bag according to claim 1, characterized in that, The inner layer structure is made by co-extrusion blow molding and includes a three-layer composite structure. The middle layer is maleic anhydride grafted modified linear low-density polyethylene, and the inner and outer outer layers are LLDPE with a melt index of 2-5 g / 10 min.
3. The leak-proof multi-layer composite container bag according to claim 1, characterized in that, The wear-resistant coating of the outer structure is a polyurethane-silicone composite coating with a thickness of 0.03-0.05 mm.
4. The leak-proof multi-layer composite container bag according to claim 1, characterized in that, The hot melt adhesive layer is made of reactive polyolefin hot melt adhesive, which forms a microporous network structure after curing.
5. The leak-proof multi-layer composite container bag according to claim 1, characterized in that, The top of the bag is equipped with multiple sets of sleeve structures for lifting.