A multi-layer composite plastic-free waterproof packaging paperboard

Abstract

This utility model discloses a multi-layer composite plastic-free waterproof packaging paperboard, comprising, from the outside to the inside, a waterproof functional layer, a first fiber substrate layer, a moisture regulating layer, a second fiber substrate layer, and a support and cushioning layer, stacked sequentially. A micron-level interlocking structure is formed at the interface between the first fiber substrate layer and the waterproof functional layer. The waterproof functional layer is composed of a plastic-free fiber layer impregnated or coated with a bio-based hydrophobic agent. The moisture regulating layer is a loose cellulose fiber web loaded with highly absorbent resin particles. The support and cushioning layer is a recycled pulp molding layer with a honeycomb or corrugated three-dimensional structure. The plastic-free composite process strengthens the interlayer bond through the interweaving of plant protein glue and hot-pressed fibers. The overall structure has high strength, strong waterproof capability, and is environmentally friendly, effectively solving the pollution problems caused by traditional plastic film packaging.

Description

Technical Field

[0001] This utility model relates to the field of packaging paper technology, specifically to a multi-layer composite plastic-free waterproof packaging paperboard. Background Technology

[0002] In the current packaging paperboard industry, traditional solutions for achieving waterproofing often rely on plastic components such as polyethylene film and polypropylene adhesives. These materials have a degradation cycle of 200-500 years in the natural environment, easily causing "white pollution." Existing plastic-free waterproof paperboards have many technical defects: relying solely on a single hydrophobic coating for waterproofing makes the coating prone to peeling and results in poor waterproofing stability; most lack moisture regulation structures, and even minor water seepage can easily lead to moisture damage to food, electronic products, and other contents; the support and cushioning layers are mostly flat designs, resulting in low stress dispersion efficiency, often leading to delamination and collapse within 48 hours of stacking; and there is a general conflict between environmental protection and mechanical performance. Some biodegradable paperboards also lack sufficient longitudinal tensile strength, failing to meet handling and stretching requirements. Utility Model Content

[0003] In order to overcome the shortcomings of existing technical solutions, this utility model provides a multi-layer composite plastic-free waterproof packaging paperboard, which can effectively solve the problems mentioned in the background art.

[0004] The technical solution adopted by this utility model to solve its technical problem is:

[0005] A multi-layer composite plastic-free waterproof packaging paperboard includes a waterproof functional layer, a first fiber substrate layer, a moisture regulating layer, a second fiber substrate layer and a support and buffer layer, which are stacked sequentially from the outside to the inside. A micron-level interlocking structure is formed at the composite interface between the first fiber substrate layer and the waterproof functional layer.

[0006] The waterproof functional layer is composed of a plastic-free fiber layer impregnated or coated with a bio-based hydrophobic agent, the moisture regulating layer is a fluffy cellulose fiber web loaded with highly absorbent resin particles, and the support and buffer layer is a recycled pulp molding layer with a honeycomb or corrugated three-dimensional structure. The layers are plastic-free composited by the interweaving of fibers generated by plant protein adhesive and hot pressing.

[0007] As a further description of the above technical solution, both the first fiber substrate layer and the second fiber substrate layer are formed from 100% recycled waste paper pulp or mixed plant fiber pulp.

[0008] As a further description of the above technical solution, in the moisture conditioning layer, the particle size of the superabsorbent resin microparticles is 80-250 mesh, and the porosity of the fluffy cellulose fiber web is 75-90%.

[0009] As a further description of the above technical solution, the height of the honeycomb or corrugated three-dimensional structure of the supporting buffer layer is 1.5-4.0 mm, and the corrugation density is 110-160 corrugations / meter.

[0010] As a further description of the above technical solution, the outer surface of the waterproof functional layer is also provided with a micro-nano composite structure imitating the hydrophobic texture of lotus leaves. The imitation hydrophobic texture is formed by synchronously pressing the molding roller during the hot pressing process, and the depth of the imitation hydrophobic texture is 10-50μm.

[0011] As a further description of the above technical solution, a barrier starch film is provided between the moisture regulating layer and the first fiber substrate layer and the second fiber substrate layer, and the thickness of the barrier starch film is 5-20μm.

[0012] As a further description of the above technical solution, the total thickness of the composite layers is 1.2-3.5 mm.

[0013] Compared with the prior art, the beneficial effects of this utility model are:

[0014] The multi-layer composite plastic-free waterproof packaging paperboard of this utility model has at least one of the following beneficial effects during use:

[0015] From an environmental perspective, all constituent materials are fully biodegradable and can degrade efficiently under standard composting conditions. Furthermore, no toxic substances such as formaldehyde, benzene solvents, or heavy metals are released during production and use, completely eliminating dependence on plastic components and effectively solving the pollution problems caused by traditional plastic film packaging. In terms of waterproofing and moisture control, the outer waterproof functional layer uses a bio-based hydrophobic agent and a lotus leaf-like hydrophobic texture to create a double water-blocking effect, reducing moisture adhesion and penetration. The middle moisture-regulating layer can absorb trace amounts of moisture that penetrate the waterproof layer, keeping the internal environment dry, suitable for packaging needs of moisture-sensitive products. Regarding mechanical and cushioning performance, the fiber-based substrate layer constructs a stable mechanical framework, ensuring overall structural strength and preventing cardboard breakage. The three-dimensional structure supporting the cushioning layer can efficiently disperse external impacts, forming a double cushioning effect with the fluffy fiber mesh, ensuring that it is not prone to collapse, delamination, or water seepage during stacking. Extensive use of recycled raw materials and agricultural waste reduces resource consumption and costs. The plastic-free composite process strengthens the interlayer bond through the interweaving of plant protein adhesives and hot-pressed fibers, and can also simultaneously complete texture processing, adapting to various packaging scenarios. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of a multi-layer composite plastic-free waterproof packaging cardboard according to the present invention.

[0017] Figure 2 This is a schematic diagram of the first part of the structure of a multi-layer composite plastic-free waterproof packaging cardboard according to the present invention;

[0018] Figure 3 This is a schematic diagram of the second part of the structure of a multi-layer composite plastic-free waterproof packaging paperboard according to the present invention.

[0019] Numbering on the map:

[0020] 1. Waterproof functional layer; 2. First fiber substrate layer; 3. Moisture regulating layer; 4. Second fiber substrate layer; 5. Support and buffer layer; 6. Lotus leaf-like hydrophobic texture; 7. Plastic-free fiber layer; 8. Interlocking structure; 9. Loose cellulose fiber web; 10. Recycled pulp molding layer; 11. Barrier starch film. Detailed Implementation

[0021] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0022] like Figure 1-3 As shown, this utility model provides a multi-layer composite plastic-free waterproof packaging paperboard, which includes a waterproof functional layer 1, a first fiber substrate layer 2, a moisture regulating layer 3, a second fiber substrate layer 4 and a support and buffer layer 5 stacked sequentially from the outside to the inside. A micron-level interlocking structure 8 is formed at the composite interface between the first fiber substrate layer 2 and the waterproof functional layer 1.

[0023] This embodiment utilizes a gradient design of 5-7 functional layers to form a complete protective system of "external water blocking → internal moisture control → structural damage resistance → strong interlayer adhesion": the outer waterproof functional layer 1 blocks the intrusion of external liquid water / moisture, the middle moisture regulating layer 3 absorbs trace amounts of permeable moisture, the support and buffer layer 5 resists external impacts, and the first / second fiber substrate layer 4 strengthens the overall structural strength. All layers are formed into a unified whole through a plastic-free composite process, avoiding delamination failure. The micron-level interlocking structure 8 between the first fiber substrate layer 2 and the waterproof functional layer 1 increases the contact area (more than 30% higher than planar composites), strengthens the interlayer adhesion, and prevents the waterproof layer from detaching.

[0024] The waterproof functional layer 1 is composed of a plastic-free fiber layer 7 impregnated or coated with a bio-based hydrophobic agent, the moisture regulating layer 3 is a fluffy cellulose fiber web 9 loaded with highly absorbent resin particles, and the support and buffer layer 5 is a recycled pulp molding layer 10 with a honeycomb or corrugated three-dimensional structure. The layers are plastic-free composited by the interweaving of fibers generated by plant protein adhesive and hot pressing.

[0025] In the waterproof functional layer 1, the coating amount of the bio-based hydrophobic agent is 8-25 g / m². 2 The basis weight of the non-plastic fiber layer 7 is 40-80 g / m³. 2 Its fiber raw materials include at least one of bleached softwood pulp, bamboo pulp, or agricultural straw pulp. The porous structure of the fluffy fiber web can absorb part of the impact force through deformation, forming a "double buffer" with the supporting buffer layer 5.

[0026] This embodiment involves impregnation / coating with a bio-based hydrophobic agent (coating amount 8-25g / m²). 2 ) non-plastic fiber layer 7 (basis weight 40-80g / m 2 The raw materials are bleached softwood pulp / bamboo pulp / straw pulp. Bio-based hydrophobic agents (such as plant waxes and lignin derivatives) form a hydrophobic film on the fiber surface, reducing the affinity of water for the paperboard and decreasing surface water absorption (corresponding to a Cobb 60s water absorption value ≤15g / m³). 2 ).

[0027] The honeycomb / corrugated three-dimensional structure (corrugation height 1.5-4.0mm, corrugation density 110-160 corrugations / meter) utilizes a hexagonal honeycomb / wavy corrugated geometric design to distribute external impact loads across multiple corrugations (increasing stress dispersion efficiency by 40%). Energy (such as the impact force during a drop) is absorbed through corrugation deformation, protecting the internal contents. The raw materials are unbleached waste paper pulp / bagasse pulp / wheat straw pulp (octane-dry basis weight 120-250g / m³). 2 It has high fiber coarseness, good stiffness, strong three-dimensional structural stability, and is not easy to collapse when stacked (no delamination / water seepage after 48 hours of stacking).

[0028] Furthermore, both the first fiber substrate layer 2 and the second fiber substrate layer 4 are formed from 100% recycled waste paper pulp or mixed plant fiber pulp. The raw materials for the first fiber substrate layer 2 and the second fiber substrate layer 4 are 100% recycled waste paper pulp or mixed plant fiber pulp, with the fibers interwoven to form a dense network structure, serving as the "mechanical skeleton" of the paperboard: longitudinal tensile strength ≥ 8.0 kN / m (resisting tensile forces during handling), and edge crush strength ≥ 7.0 kN / m (withstanding vertical pressure during stacking). The first fiber substrate layer 2 connects the waterproof functional layer 1 and the moisture regulating layer 3, and the second fiber substrate layer 4 connects the moisture regulating layer 3 and the support and buffer layer 5. Through the balance of fiber flexibility and rigidity, the paperboard is prevented from becoming brittle.

[0029] Furthermore, in the moisture regulating layer 3, the superabsorbent polymer (SAP) particles have a size of 80-250 mesh, and the porosity of the loose cellulose fiber web 9 is 75-90%. The superabsorbent polymer particles are cross-linked polyacrylates or starch-grafted acrylates. When trace amounts of moisture penetrate the waterproof layer, the SAP adsorbs the moisture through hydrogen bonds, achieving a water absorption rate of 500-1000 times its own weight. After absorbing water, it forms a gel that does not leak out, maintaining a dry internal environment (suitable for moisture-sensitive products such as food and electronics).

[0030] Furthermore, the honeycomb or corrugated three-dimensional structure of the supporting buffer layer 5 has a flute height of 1.5-4.0 mm and a flute density of 110-160 flutes / meter. Its raw material is at least one of unbleached waste paper pulp, bagasse pulp, or wheat straw pulp, with an oven-dry basis weight of 120-250 g / m³. 2 The plant protein adhesive is a modified soybean protein adhesive or wheat gluten protein adhesive, with a solid content of 25-40% and an application rate of 4-12 g / m³. 2 (Single-sided), the hot pressing temperature is 140-180℃, the pressure is 0.8-1.5MPa, and the time is 10-30 seconds.

[0031] Furthermore, the outer surface of the waterproof functional layer 1 is also provided with a micro-nano composite structure imitating a lotus leaf hydrophobic texture 6. The imitation lotus leaf hydrophobic texture 6 is formed by synchronously imprinting during the hot pressing process using a molding roller, and the depth of the imitation lotus leaf hydrophobic texture 6 is 10-50μm. The outer surface imitation lotus leaf hydrophobic texture 6 (depth 10-50μm, synchronously imprinted by hot pressing) uses a "micron bump + nano groove" structure to make the water droplet contact angle >150° and the roll-off angle <10°, making it difficult for water droplets to adhere and causing them to roll off quickly, further blocking the penetration path of liquid water.

[0032] Furthermore, a barrier starch film 11 is provided between the moisture regulating layer 3 and the first fiber substrate layer 2 and the second fiber substrate layer 4. The thickness of the barrier starch film 11 is 5-20 μm. The moisture permeability of the barrier starch film is ≤200 g / (m³). 2 • 24h). Interlayer barrier starch film 11 (thickness 5-20μm, moisture permeability ≤200g / (m²) 2 • 24h) can block the migration of moisture between the substrate layer and the conditioning layer, and prevent the SAP from affecting the strength of the substrate layer after absorbing moisture.

[0033] Furthermore, the total thickness of the composite layers is 1.2-3.5 mm. The Cobb 60s water absorption value of the packaging paperboard is ≤15 g / m³. 2 Tensile strength ≥ 8.0 kN / m (longitudinal), edge compressive strength ≥ 7.0 kN / m, and no delamination or water seepage after 48 hours under stacking load.

[0034] All components of the packaging paperboard are fully biodegradable, with a biodegradability rate of ≥90% within 180 days under standard composting conditions. The plant protein adhesive contains 25-40% protein solids; under hot pressing at 140-180℃, the protein molecules denature and cross-link, forming a strong bond; the application rate is 4-12 g / m³. 2 (Single-sided) allows for precise control of bonding strength, preventing excessive adhesive application that could lead to stiff cardboard. During hot pressing (0.8-1.5MPa, 10-30 seconds), the fibers in each layer interweave under pressure and temperature (forming "fiber entanglement nodes"), working synergistically with the protein adhesive to increase interlayer bonding strength by over 25%, ensuring no delamination after 48 hours of stacking. The plant-based protein adhesive is free of formaldehyde and benzene solvents, and the bio-based hydrophobic agent is free of heavy metals; no toxic substances are released during production and use.

[0035] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A multi-layer composite plastic-free waterproof packaging paperboard, characterized in that: It includes a waterproof functional layer, a first fiber substrate layer, a moisture regulating layer, a second fiber substrate layer and a support and buffer layer, which are stacked and combined in sequence from the outside to the inside. At the composite interface between the first fiber substrate layer and the waterproof functional layer, a micron-level interlocking structure is formed. The waterproof functional layer is composed of a plastic-free fiber layer impregnated or coated with a bio-based hydrophobic agent, the moisture regulating layer is a fluffy cellulose fiber web loaded with highly absorbent resin particles, and the support and buffer layer is a recycled pulp molding layer with a honeycomb or corrugated three-dimensional structure. The layers are plastic-free composited by the interweaving of fibers generated by plant protein adhesive and hot pressing.

2. The multi-layer composite plastic-free waterproof packaging paperboard according to claim 1, characterized in that: Both the first fiber substrate layer and the second fiber substrate layer are formed from 100% recycled waste paper pulp or mixed plant fiber pulp.

3. The multi-layer composite plastic-free waterproof packaging paperboard according to claim 1, characterized in that: In the moisture conditioning layer, the particle size of the superabsorbent resin microparticles is 80-250 mesh, and the porosity of the fluffy cellulose fiber web is 75-90%.

4. The multi-layer composite plastic-free waterproof packaging paperboard according to claim 1, characterized in that: The honeycomb or corrugated three-dimensional structure of the supporting buffer layer has a rib height of 1.5-4.0 mm and a rib density of 110-160 ribs / meter.

5. The multi-layer composite plastic-free waterproof packaging paperboard according to claim 1, characterized in that: The outer surface of the waterproof functional layer is also provided with a micro-nano composite structure imitating the hydrophobic texture of lotus leaves. The imitation lotus leaf hydrophobic texture is formed by synchronously pressing by a molding roller during hot pressing, and the depth of the imitation lotus leaf hydrophobic texture is 10-50μm.

6. The multi-layer composite plastic-free waterproof packaging paperboard according to claim 1, characterized in that: A barrier starch film is provided between the moisture regulating layer and the first fiber substrate layer and the second fiber substrate layer, and the thickness of the barrier starch film is 5-20 μm.

7. The multi-layer composite plastic-free waterproof packaging paperboard according to claim 1, characterized in that: The total thickness of the composite layers is 1.2-3.5 mm.

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