Composite luggage shell and preparation method thereof

Abstract

The invention discloses a composite luggage shell and a preparation method thereof.The composite luggage shell comprises a first set of BOPP film layers, a woven cloth middle layer and a second set of BOPP film layers which are sequentially arranged in a stacked mode, and the woven cloth middle layer is PP flat filament woven cloth enhanced through stretching orientation; the first group of BOPP film layers and the second group of BOPP film layers are respectively formed by laminating and compounding a plurality of transparent BOPP film layers. The composite luggage shell is prepared through a lamination hot press molding process, has the characteristics of low cost, high strength, light weight and excellent low-temperature performance, and can clearly retain the weaving texture and texture of the PP flat filament woven cloth, and the comprehensive performance and the cost performance are remarkably improved.

Description

Technical Field

[0001] This invention belongs to the field of luggage, specifically relating to a composite luggage shell and its preparation method. Background Technology

[0002] As essential everyday travel gear, the performance, cost, and appearance of luggage shells directly determine a product's market competitiveness. Currently, most luggage shells on the market are injection molded from PP or modified PP materials, or vacuum formed from materials such as PC. However, due to limitations in materials and manufacturing processes, neither injection molding nor vacuum forming can perfectly balance lightweight and strength.

[0003] CN121492371A discloses a shell formed by hot pressing of transparent BOPP film lamination, which has the characteristics of low production cost, high molding efficiency and high mechanical strength. However, since the BOPP film itself has no obvious texture, the shell has a monotonous appearance and poor texture, which makes it difficult to meet the aesthetic needs of the mid-to-high-end market.

[0004] Furthermore, existing suitcase shells are prone to embrittlement and reduced impact resistance in low-temperature environments, especially in cold northern regions where the shells are easily damaged, affecting product lifespan. Therefore, developing a suitcase shell that balances cost, strength, appearance, and low-temperature performance has become a pressing technical challenge in this field. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, the present invention aims to provide a composite bag shell made of stretched orientation reinforced PP flat yarn woven fabric and transparent BOPP film as raw materials and its preparation method. The composite bag shell has the characteristics of low cost, high strength, light weight and excellent low temperature performance, and can clearly retain the weaving texture and feel of PP flat yarn woven fabric.

[0006] This invention is achieved through the following technical solution:

[0007] A composite luggage shell includes a first group of BOPP film layers, an intermediate layer, and a second group of BOPP film layers stacked sequentially. The intermediate layer is a PP flat yarn woven fabric reinforced by stretching and orientation. The first group of BOPP film layers and the second group of BOPP film layers are each composed of multiple layers of transparent BOPP film layers.

[0008] This invention employs a rational composite combination of stretched and oriented PP flat yarn woven fabric and transparent BOPP film. The PP flat yarn woven fabric is a single layer positioned between the first and second BOPP film layers. The first transparent BOPP film layer clearly highlights the woven texture of the intermediate PP flat yarn woven fabric and enhances its surface gloss, thus preserving the natural woven texture while overcoming the drawbacks of pure BOPP film shells being textureless and monotonous in appearance. Furthermore, the high strength of the first and second BOPP film layers and the tensile properties of the PP flat yarn woven fabric achieve a synergistic reinforcement effect, resulting in a composite bag shell that combines low cost and high strength, significantly improving overall performance and cost-effectiveness.

[0009] The transparent BOPP film described in this invention is readily available through commercial purchase.

[0010] In a preferred embodiment of the present invention, the thickness of the films in the first group of BOPP film layers and the second group of BOPP film layers is 0.01-0.08 mm, and the multiple layers are stacked to ensure the necessary thickness of the shell.

[0011] This invention allows for the adjustment of the thickness or number of BOPP film layers in the first and second groups to meet the thickness requirements of different sized luggage shells. Typically, the thickness of the shell material for a 20-inch luggage is 1.00mm-1.10mm, for a 24-inch luggage is 1.10mm-1.20mm, and for a 28-inch luggage is 1.20mm-1.30mm.

[0012] As a preferred embodiment of the present invention, the transparent BOPP film is tested according to GB / T 1040.3-2006, with longitudinal tensile strength > 120MPa, transverse tensile strength > 270MPa, longitudinal nominal strain at break > 130%, and transverse nominal strain at break > 45%, ensuring the tensile performance and toughness of the shell.

[0013] As a preferred embodiment of the present invention, the basis weight of the PP flat yarn woven fabric of the present invention is 80g / ㎡-150g / ㎡.

[0014] In a preferred embodiment of the present invention, the warp tensile load of the PP flat yarn woven fabric is >360 N / 50 mm and the weft tensile load is >340 N / 50 mm, as measured according to GB / T 1040.3-2006.

[0015] The present invention also provides a method for preparing the above-mentioned composite bag shell, comprising the following steps:

[0016] (1) Raw material pretreatment: Cut the stretched and oriented reinforced PP flat yarn woven fabric and transparent BOPP film to the size that matches the dimensions of the suitcase shell, and set them aside;

[0017] (2) Laying in layers: Lay in layers in the order of multiple transparent BOPP film → one layer of PP flat yarn woven fabric → multiple transparent BOPP film;

[0018] (3) Preheating the press plate: Place the layered raw materials into the hot press to preheat the press plate;

[0019] (4) Hot pressing: The preheated sheet is placed into a hot pressing mold for hot pressing;

[0020] (5) Pressure holding and cooling: After hot pressing, the pressure is held until the mold temperature drops below 60°C, then the mold is opened to obtain the composite bag shell.

[0021] The composite bag shell of this invention is made of transparent BOPP film and PP flat yarn woven fabric through a lamination hot pressing molding process. By optimizing the hot pressing molding process parameters, a firm bond between the BOPP film and the PP flat yarn woven fabric can be achieved, while avoiding damage and deformation of the woven texture due to scratches, thus balancing the molding effect and appearance.

[0022] In a preferred embodiment of the present invention, in step (3), the preheating temperature is 145-155℃, the preheating pressure is 0.2-0.5 MPa, and the pressurization time is 3-5 minutes.

[0023] In a preferred embodiment of the present invention, in step (4), the hot pressing temperature is 163℃-167℃, the pressure is 2.0-5.0 MPa, and the pressurization time is 30-80s.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] This invention adopts a composite structure of "multi-layer BOPP film - PP flat yarn woven fabric - multi-layer BOPP film". The PP flat yarn woven fabric is located between the two sets of BOPP film. The outer transparent BOPP film can clearly show the woven texture, while improving the gloss of the shell surface. It not only fully preserves the natural woven texture, but also solves the drawbacks of pure BOPP film shells having no texture and monotonous appearance. The appearance and texture are excellent, meeting the appearance requirements of mid-to-high-end bags.

[0026] This invention utilizes the high strength properties of BOPP film and the tensile properties of PP flat yarn woven fabric to achieve a synergistic reinforcement effect, increasing the tensile strength of the shell by more than 3 times compared to traditional PP injection molded shells, and reducing the weight by more than 30%, thus achieving a balance between lightweight and strength; moreover, it exhibits excellent low-temperature performance without cracking when dropped at a low temperature of -35℃.

[0027] This invention uses only one layer of PP flat yarn woven fabric, while the remaining layers are made of low-cost transparent BOPP film, which greatly reduces the amount of high-cost materials used, achieving both high performance and low cost, and making it highly competitive in the market. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of a composite luggage shell. Detailed Implementation

[0029] The present invention will be further illustrated below through specific embodiments. The following embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following embodiments.

[0030] Unless otherwise specified, all materials used in this invention can be purchased commercially or prepared using conventional methods.

[0031] The materials used in this invention are sourced from the following sources:

[0032] PP flat yarn woven fabric: produced by Suzhou Lingji Textile Technology Co., Ltd., with a width of 140cm, a weight of 130g / ㎡, and a maximum tensile load of 397 N / 50mm in the warp and 349 N / 50mm in the weft. Test standard: GB / T 1040.3-2006.

[0033] Transparent BOPP film: Produced by Qingdao Xinguangheng Packaging Materials Co., Ltd., with a width of 140cm, a thickness of 40µm, a longitudinal tensile strength of 128 MPa, a transverse tensile strength of 271 MPa, a longitudinal breaking nominal strain of 133%, and a transverse breaking nominal strain of 48%. Test standard: GB / T 1040.3-2006.

[0034] Example 1: Preparation of a 20-inch luggage shell

[0035] like Figure 1 As shown, a composite luggage shell includes a first group of BOPP film layers 1 stacked sequentially.

[0036] The intermediate layer 2 and the second BOPP film layer 3 are respectively composed of 11 layers of transparent BOPP film. The intermediate layer 2 is a layer of PP flat yarn woven fabric that has been stretched and oriented. The entire board is 1.026mm thick.

[0037] Its preparation process includes the following steps:

[0038] (1) Cut the BOPP film and PP flat yarn woven fabric into rectangles that match the front of the suitcase;

[0039] (2) Lay the film and PP flat yarn woven fabric in the order of 11 layers of transparent BOPP film → 1 layer of PP flat yarn woven fabric → 11 layers of transparent BOPP film;

[0040] (3) Preheating the plate: The laminated film and cloth are placed in a hot press for preheating and plate making. The preheating pressure is 0.2 MPa; the pressurization time is 4 min; and the preheating temperature is 145℃.

[0041] (4) Hot pressing: The preheated sheet is placed into a hot pressing mold for hot pressing. The hot pressing temperature is 163℃, the pressure is 2.5 MPa, and the pressing time is 80s.

[0042] (5) Pressure holding: After hot pressing, pressure is held until the mold temperature drops below 60°C, and the composite bag shell is obtained by opening the mold.

[0043] Example 2: Preparation of a 24-inch luggage shell

[0044] The composite bag shell structure is the same as in Example 1, wherein the first BOPP film layer 1 is 10 layers of transparent BOPP film, the middle layer 2 is 1 layer of PP flat yarn woven fabric reinforced by stretching and orientation, the second BOPP film layer 3 is 15 layers of transparent BOPP film, and the entire board is 1.146mm thick.

[0045] Its preparation process includes the following steps:

[0046] (1) Cut the BOPP film and PP flat yarn woven fabric into rectangles that match the front of the suitcase;

[0047] (2) Lay the film and PP flat yarn woven fabric in the order of 10 layers of transparent BOPP film → 1 layer of PP flat yarn woven fabric → 15 layers of transparent BOPP film;

[0048] (3) Preheating the plate: The laminated film and cloth are placed in a hot press for preheating and plate making. The preheating pressure is 0.3 MPa; the pressurization time is 3 min; and the preheating temperature is 150℃.

[0049] (4) Hot pressing: The preheated sheet is placed into a hot pressing mold for hot pressing. The hot pressing temperature is 165℃, the pressure is 3.0MPa, and the pressing time is 70s.

[0050] (5) Pressure holding: After hot pressing, pressure is held until the mold temperature drops below 60°C, and the composite bag shell is obtained by opening the mold.

[0051] Example 3: Preparation of 28-inch luggage shell

[0052] The composite bag shell structure is the same as in Example 1, wherein the first BOPP film layer 1 is 5 layers of transparent BOPP film, the middle layer 2 is 1 layer of PP flat yarn woven fabric that has been stretched and oriented, the second BOPP film layer 3 is 22 layers of transparent BOPP film, and the entire board is 1.226mm thick.

[0053] Its preparation process includes the following steps:

[0054] (1) Cut the BOPP film and PP flat yarn woven fabric into rectangles that match the front of the suitcase;

[0055] (2) Lay the film and PP flat yarn woven fabric in the order of 5 layers of transparent BOPP film → 1 layer of PP flat yarn woven fabric → 22 layers of transparent BOPP film;

[0056] (3) Preheating the plate: The laminated film and fabric are placed in a hot press for preheating and plate making. The preheating pressure is 0.5 MPa; the pressurization time is 5 min; and the preheating temperature is 155℃.

[0057] (4) Hot pressing: The preheated sheet is placed into a hot pressing mold for hot pressing. The hot pressing temperature is 167℃, the pressure is 5.0 MPa, and the pressing time is 45s.

[0058] (5) Pressure holding: After hot pressing, pressure is held until the mold temperature drops below 60°C, and the composite bag shell is obtained by opening the mold.

[0059] Comparative Example 1: PP Injection Molded Box Shell

[0060] Molten modified PP was directly injected into 20-inch, 24-inch, and 28-inch mold cavities using an injection molding machine to obtain three different sizes of box shells.

[0061] Comparative Example 2: Pure BOPP membrane housing

[0062] 26 layers of transparent BOPP film were stacked and prepared according to the process of steps (3)-(5) in Example 1 to obtain a pure BOPP film shell with a total thickness of 1.04 mm.

[0063] Table 1 Performance test results of the examples and comparative examples

[0064] Test Project Test Standards Test conditions Comparative Example 1 Comparative Example 2 Example 1 Example 2 Example 3 Tensile strength (MPa) ASTM D638 50mm / min 23℃ 14.24 92.75*50.75** 107.38 *65.4 ** 109.44 *59.17** 96.36 *54.59 ** proportion ASTM D792 23℃ 0.89-0.92 0.88-0.91 0.88-0.91 0.88-0.91 0.88-0.91 Weight of the box cover (g) Electronic scale weighing 23℃ 420 (20-inch) 725 (24-inch) 1018 (28-inch) 291 280 481 689 drop test QB / T 2155-2018 Temperature dropped to -35℃ Defective (box shell cracked) qualified qualified qualified qualified Load-vibration life test QB / T 2155-2010 10,000 times Unqualified qualified qualified qualified qualified Appearance No woven texture, monotonous appearance No woven texture, monotonous appearance The woven fabric has a clear texture The woven fabric has a clear texture The woven fabric has a clear texture

[0065] * Take samples vertically on the left or right side of the enclosure; ** Take samples horizontally above or below the enclosure.

[0066] As shown in Table 1, under the condition that the specific gravity is basically the same, compared with the traditional PP injection molded box shell of Comparative Example 1, the tensile strength of the composite box shell prepared by the present invention is more than 3 times higher and the weight is more than 30% lighter, achieving a balance between lightweight and strength. Moreover, it does not crack when dropped at a low temperature of -35℃, and has excellent low temperature performance.

[0067] As can be seen from the comparison between Example 1 and Comparative Example 2, the composite bag shell prepared in Example 1 of the present invention not only has a natural woven texture in appearance, but also has the synergistic enhancement of BOPP film and PP flat yarn woven fabric, and its tensile strength is also better than that of Comparative Example 2, resulting in better overall performance.

Claims

1. A composite case shell, characterized in that, The composite case shell includes a first group of BOPP film layers, an intermediate layer and a second group of BOPP film layers stacked in sequence. The intermediate layer is a PP flat yarn woven fabric that has been stretched and oriented. The first group of BOPP film layers and the second group of BOPP film layers are each composed of multiple layers of transparent BOPP film layers.

2. The composite luggage shell according to claim 1, characterized in that, The thickness of the first group of BOPP film layers and the second group of BOPP film layers is 0.01mm - 0.08mm.

3. The composite luggage shell according to claim 1, characterized in that, The transparent BOPP film was tested according to GB / T1040.3-2006, with longitudinal tensile strength >120MPa, transverse tensile strength >270MPa, longitudinal nominal strain at break >130%, and transverse nominal strain at break >45%.

4. The composite luggage shell according to claim 1, characterized in that, The weight of the PP flat yarn woven fabric is 80g / ㎡-150g / ㎡.

5. The composite luggage shell according to claim 1, characterized in that, The PP flat yarn woven fabric has a warp tensile load > 360 N / 50 mm and a weft tensile load > 340 N / 50 mm, as determined according to GB / T 1040.3-2006.

6. The method for preparing the composite bag shell according to any one of claims 1 to 5, characterized in that, Includes the following steps: (1) Raw material pretreatment: Cut the stretched and oriented reinforced PP flat yarn woven fabric and transparent BOPP film to the size that matches the size of the bag shell, and set aside; (2) Laying in layers: Lay in layers in the order of multiple transparent BOPP film → one layer of PP flat yarn woven fabric → multiple transparent BOPP film; (3) Preheating the press plate: Place the layered raw materials into the hot press to preheat the press plate; (4) Hot pressing: The preheated sheet is placed into a hot pressing mold for hot pressing; (5) Pressure holding and cooling: After hot pressing, the pressure is held until the mold temperature drops below 60°C, then the mold is opened to obtain the composite bag shell.

7. The method for preparing the composite bag shell according to claim 6, characterized in that, In step (3), the preheating temperature is 145-155℃, the preheating pressure is 0.2-0.5 MPa, and the pressurization time is 3-5 minutes.

8. The method for preparing the composite bag shell according to claim 6, characterized in that, In step (4), the hot pressing temperature is 163℃-167℃, the pressure is 2.0-5.0 MPa, and the pressurization time is 30-80s.

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