Wear-resistant trunk shell with dot lines and preparation process of wear-resistant trunk shell

Abstract

The invention relates to the technical field of bags and suitcases, in particular to a wear-resistant luggage case shell with dot lines and a preparation process of the wear-resistant luggage case shell. The wear-resistant dot grain luggage case shell comprises a shell body, at least three layers are arranged on the shell body and sequentially comprise a first coating, a base material layer and a second coating from inside to outside, a plurality of wear-resistant dots are arranged on a base material, and the wear-resistant dots form grains on the outer surface of the shell body, so that the luggage case shell is provided with the grains. The effects of scratch resistance, touch feeling and visual attractiveness are achieved; the base material layer is prepared from the following raw materials in parts by weight: 120 to 135 parts of thermoplastic polymer, 80 to 100 parts of ethylene-vinyl acetate copolymer, 30 to 40 parts of maleic anhydride, 10 to 20 parts of tetraethyl silicate, 20 to 30 parts of PC-ABS copolymer, 20 to 50 parts of cow leather fiber and 10 to 20 parts of polyhydroxyalkanoate, so that the shell is light, has good impact toughness and wear resistance and can be directly subjected to injection molding.

Description

Technical Field

[0001] The present invention relates to the technical field of luggage, and in particular to a wear-resistant dot pattern luggage shell and a preparation process thereof. Background Art

[0002] A suitcase, also known as a travel case or trolley case, is a type of luggage used to carry items when traveling. Early suitcases were made of wood or other heavy materials. With the rise in popularity of air travel, suitcases have become made of lighter materials such as hard plastic or fabric.

[0003] Plastic suitcases are often embossed to create a textured surface for scratch resistance, tactile feel, and visual aesthetics. Existing production methods typically use extrusion machines to produce sheets from materials such as PC, ABS, and PP. During the extrusion process, the sheets are embossed directly with an embossing wheel. The sheets are then cut to appropriate sizes, heated to soften them, and then vacuum-molded using a male mold for the shell to create the suitcase shell.

[0004] However, the existing manufacturing method embosses the sheet material before vacuum forming. Due to the different forming ratios of different parts of the shell, the original embossed texture may be stretched and flattened, resulting in an uneven or even flat embossed texture, affecting the aesthetic appearance of the suitcase. In addition, existing suitcases do not have anti-fouling functions, which can easily cause stains to remain on the shell surface, affecting the use of the suitcase.

[0005] In view of this, the present application proposes a wear-resistant dot pattern luggage shell and a preparation process thereof, so that the shell pattern is uniform, thereby improving the appearance and texture of the luggage. Summary of the Invention

[0006] The purpose of the present invention is to solve at least one of the technical problems existing in the prior art and to provide a wear-resistant dot pattern luggage case shell and a preparation process thereof.

[0007] To achieve the above-mentioned objectives, the technical solution adopted by the present invention is as follows: a wear-resistant dot-patterned suitcase shell, comprising a shell, the shell being provided with at least three layers, namely, a first coating layer, a substrate layer, and a second coating layer from the inside out, the substrate being provided with a plurality of wear-resistant dots, and the plurality of wear-resistant dots forming the texture on the outer surface of the shell, so that the suitcase shell has a texture to achieve scratch resistance, tactile feel, and visual aesthetics; the substrate layer is composed of the following raw materials in parts by weight, including 120-135 parts of a thermoplastic polymer, 80-100 parts of an ethylene-vinyl acetate copolymer, 30-40 parts of maleic anhydride, 10-20 parts of tetraethyl silicate, 20-30 parts of a PC-ABS copolymer, 20-50 parts of kraft fiber, and 10-20 parts of a polyhydroxyalkanoate.

[0008] Thermoplastic polymers and ethylene-vinyl acetate copolymers are used as the main raw materials to provide basic hardness, load-bearing capacity, wear resistance and impact resistance. Maleic anhydride, PC-ABS copolymer, tetraethyl silicate, cowhide fiber and polyhydroxyalkanoate are added to improve the mechanical strength, crack resistance and wear resistance of the suitcase shell. Among them, the combination of thermoplastic polymer and ethylene-vinyl acetate copolymer is more conducive to reducing the density of the suitcase shell; the added PC-ABS copolymer, tetraethyl silicate, cowhide fiber and polyhydroxyalkanoate work together to reduce the brittleness of the suitcase shell, improve its crack resistance, mechanical strength and impact resistance, thereby increasing the service life of the suitcase shell; the added cowhide fiber forms an effective skeleton in the system, thereby increasing the impact strength of the ethylene-vinyl acetate copolymer. The cowhide fiber itself has good mechanical strength and can play a good reinforcing role on the ethylene-vinyl acetate copolymer. It forms an effective skeleton in the system, thereby bearing the destructive stress from the ethylene-vinyl acetate copolymer, so that the ethylene-vinyl acetate copolymer consumes a large amount of energy to absorb the impact energy before destruction, effectively preventing the ethylene-vinyl acetate copolymer from breaking, thereby effectively improving the impact strength of the suitcase shell.

[0009] Furthermore, the thickness of the first coating layer or the second coating layer is 0.1-0.3 times the thickness of the substrate layer; the first coating layer and the second coating layer are both polyurethane layers containing modified glass beads, thereby improving the wear resistance and anti-fouling properties of the suitcase shell.

[0010] Furthermore, the thermoplastic polymer is a mixture of TPE and TPU in a weight ratio of 3-5:1. Using too little thermoplastic polymer will not significantly improve the toughness of the luggage shell; using too much thermoplastic polymer will actually reduce the strength and rigidity of the luggage shell.

[0011] Furthermore, the length of the cowhide fiber is 0.1-0.5 mm, and the fineness of the cowhide fiber is 0.8-1.5 tex, which can promote its uniform distribution in the suitcase shell and avoid the agglomeration of the cowhide fibers. After processing, the retained length of the cowhide fiber tends to the critical optimal length, has lower warping and better dimensional stability, helps to increase the fiber content and mechanical properties, and makes the suitcase shell have higher impact strength. At the same time, it can also reduce the warping of the suitcase shell, thereby improving its pressure resistance and crack resistance.

[0012] Furthermore, the PC-ABS copolymer is formed by mixing PC having a melt index of 3-5 g / 10 min and a density of 1.20-1.22 g / cm3 with ABS having a melt index of 1-3 g / 10 min and a density of 1.01-1.04 g / cm3 in a weight ratio of 5-8:1, thereby improving the mechanical strength of the suitcase shell.

[0013] Furthermore, the ethylene-vinyl acetate copolymer is a mixture of ethylene and vinyl acetate in a weight ratio of 1:2.0-4.5, and the ethylene-vinyl acetate copolymer has a melt index of 10-15 g / 10 min and a density of 0.928-0.957 g / cm3, thereby improving the environmental stress cracking resistance, impact strength and tear strength of the luggage shell.

[0014] Furthermore, the polyhydroxyalkanoate has a weight-average molecular weight of 200,000-300,000, a melt index of 15-20 g / 10 min, and a density of 1.20-1.25 g / cm3. This prevents the polyhydroxyalkanoate from crystallizing too slowly during processing, improves the integrity of its spherulite structure, and thereby fully utilizes its internal toughness. When subjected to external forces, it can quickly dissipate the generated internal stress, thereby improving its crack resistance. Furthermore, the polyhydroxyalkanoate has a moisture content of 0.5-1 wt%. This prevents degradation of the polyhydroxyalkanoate due to moisture and temperature during processing.

[0015] The polyhydroxyalkanoate strengthens the ethylene-vinyl acetate copolymer, increasing the hardness and toughness of the luggage shell, thereby improving the load-bearing performance of the luggage shell. In addition, the polyhydroxyalkanoate is biodegradable and, when combined with cowhide fiber, can decompose the luggage shell into several small molecules under degradation conditions, thereby promoting the decomposition and recycling of the luggage shell and reducing adverse impacts on the environment.

[0016] The preparation process of the wear-resistant dot pattern luggage shell includes the following steps:

[0017] S1. Weighing raw materials by weight, first adding the raw materials thermoplastic polymer, PC-ABS copolymer, and a portion of maleic anhydride into a twin-screw extruder containing an organic solvent for mixing, then adding the raw materials ethylene-vinyl acetate copolymer, polyhydroxyalkanoate, and the remaining maleic anhydride, mixing for a period of time, and finally adding kraft fiber, continuing to mix, followed by extrusion and granulation to obtain a mixture, thereby helping to increase the fiber content and mechanical properties, making the luggage shell have higher impact strength, and also reducing the warpage of the luggage shell, thereby improving its pressure resistance and crack resistance;

[0018] S2. The mixture obtained in step S1 is put into an injection molding machine, and injection molding is performed at a temperature of 150-180° C. and cooled to obtain a substrate layer to prevent a decrease in molding rate due to excessively high temperature;

[0019] S3. Apply the polyurethane material containing modified glass beads on the base material layer obtained in step S2 and cure it to obtain a wear-resistant polka dot pattern suitcase shell.

[0020] Furthermore, the preparation of the polyurethane material containing modified glass beads includes adding xylene diisocyanate and polypropylene glycol in a certain proportion into a three-necked flask, stirring at a constant temperature of 50°C in an oil bath for 1 hour, then heating to 80°C and continuing to stir for 2 hours to generate a polyurethane prepolymer; then adding 1,4-butanediol, phosphate ester, and modified glass beads to the prepolymer, continuing to stir and heat for 3 hours to obtain a polyurethane material containing modified glass beads.

[0021] Furthermore, the modified glass beads are composed of glass beads and polycatecholamine. Since the surface of polycatecholamine contains a large amount of -OH and -NH2, it can directly have better bonding with polyurethane, thereby improving the strength of the composite material, making the suitcase shell have good anti-fouling properties and wear resistance, and effectively preventing residual stains on the shell surface from affecting the use of the suitcase.

[0022] Compared with the existing technology, the technical solution of this application has the following beneficial effects:

[0023] 1. The present application provides a shell with at least three layers, comprising, from the inside out, a first coating layer, a substrate layer, and a second coating layer. The substrate layer is provided with a plurality of wear-resistant dots, which form a texture on the outer surface of the shell, so that the luggage shell has a texture to achieve scratch resistance, tactile feel, and visual aesthetics. The substrate layer contains a thermoplastic polymer, ethylene-vinyl acetate copolymer, maleic anhydride, tetraethyl silicate, and PC-ABS copolymer, making the shell lightweight, with good impact toughness and wear resistance, and can be directly injection molded.

[0024] 2. The coating of the present application is made of polyurethane material with modified glass beads, which makes the suitcase shell have good anti-fouling performance and wear resistance, and effectively prevents residual stains on the shell surface from affecting the use of the suitcase.

[0025] 3. The application uses polyhydroxyalkanoate to make the shell have good biodegradability and be environmentally friendly.

[0026] 4. The preparation method of the present invention is simple to operate, easy to control, has high production efficiency, low production cost, and can be used for large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the structure of the wear-resistant dot pattern suitcase shell in a preferred embodiment of the present invention.

[0028] Reference numerals: 1, housing; 2, wear-resistant dots. DETAILED DESCRIPTION

[0029] The technical solutions of the present invention will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0030] Example 1

[0031] like Figure 1 As shown, the wear-resistant dot-patterned suitcase shell includes a shell 1. The shell 1 is provided with at least three layers, including a first coating layer, a base material layer, and a second coating layer from the inside to the outside. The base material is provided with a plurality of wear-resistant dots 2, and the plurality of wear-resistant dots 2 constitute the outer surface pattern of the shell; the base material layer is composed of the following raw materials in parts by weight, including 128 parts of thermoplastic polymer, 90 parts of ethylene-vinyl acetate copolymer, 35 parts of maleic anhydride, 15 parts of tetraethyl silicate, 25 parts of PC-ABS copolymer, 35 parts of kraft fiber, and 15 parts of polyhydroxyalkanoate.

[0032] The thickness of the first coating layer or the second coating layer is 0.2 times the thickness of the substrate layer; the first coating layer and the second coating layer are both polyurethane material layers containing modified glass beads.

[0033] The thermoplastic polymer is formed by mixing TPE and TPU in a weight ratio of 4:1.

[0034] The length of the cowhide fiber is 0.3 mm, and the fineness of the cowhide fiber is 0.11 tex.

[0035] The PC-ABS copolymer is composed of a melt index of 4 g / 10 min and a density of 1.21 g / cm 3 PC with a melt index of 2g / 10min and a density of 1.02g / cm 3 ABS is mixed in a weight ratio of 6:1.

[0036] The ethylene-vinyl acetate copolymer is a mixture of ethylene and vinyl acetate in a weight ratio of 1:3.2. The ethylene-vinyl acetate copolymer has a melt index of 12.5 g / 10 min and a density of 0.943 g / cm 3 .

[0037] The weight average molecular weight of the polyhydroxyalkanoate is 250,000, the melt index of the polyhydroxyalkanoate is 17.5 g / 10 min, and the density is 1.22 g / cm 3 ; The water content of the polyhydroxyalkanoate is 0.75wt%.

[0038] The preparation process of the wear-resistant dot pattern luggage shell includes the following steps:

[0039] S1. Weigh the raw materials by weight, first put the raw thermoplastic polymer, PC-ABS copolymer, and part of maleic anhydride into a twin-screw extruder containing an organic solvent, and mix them at 240° C. for 2 hours; then add the raw ethylene-vinyl acetate copolymer, polyhydroxyalkanoate, and the remaining maleic anhydride, and mix them at 200° C. for 1 hour; finally, add kraft fiber, mix them at 180° C. for 4 hours, and then extrude and granulate to obtain a mixture;

[0040] S2. The mixture obtained in step S1 is put into an injection molding machine, and injection molding is performed at a temperature of 165° C. and cooled to obtain a substrate layer to prevent a decrease in molding rate due to excessively high temperature;

[0041] S3. Apply the polyurethane material containing modified glass beads on the base material layer obtained in step S2 and cure it to obtain a wear-resistant polka dot pattern suitcase shell.

[0042] The preparation of the polyurethane material containing modified glass beads comprises the following steps: adding xylene diisocyanate and polypropylene glycol in a certain proportion into a three-necked flask, stirring at a constant temperature of 50° C. in an oil bath for 1 hour, then heating to 80° C. and continuing stirring for 2 hours to generate a polyurethane prepolymer; then adding 1,4-butanediol, phosphate ester, and modified glass beads into the prepolymer, continuing stirring and heating for 3 hours to obtain the polyurethane material containing modified glass beads.

[0043] The modified glass beads are composed of glass beads and polycatecholamine. Because the surface of polycatecholamine contains a large amount of -OH and -NH2, it can directly form a better bond with polyurethane, thereby improving the strength of the composite material. This makes the suitcase shell have good anti-fouling properties and wear resistance, and effectively prevents residual stains on the shell surface from affecting the use of the suitcase.

[0044] Example 2

[0045] A wear-resistant polka-dot luggage case shell comprises a shell having at least three layers, namely, a first coating layer, a substrate layer, and a second coating layer, from the inside out. The substrate layer is provided with a plurality of wear-resistant dots, which constitute the outer surface pattern of the shell. The substrate layer is made of the following raw materials in parts by weight: 120 parts of a thermoplastic polymer, 80 parts of an ethylene-vinyl acetate copolymer, 30 parts of maleic anhydride, 10 parts of tetraethyl silicate, 20 parts of a PC-ABS copolymer, 20 parts of kraft fiber, and 10 parts of a polyhydroxyalkanoate.

[0046] The thickness of the first coating layer or the second coating layer is 0.1 times the thickness of the substrate layer; the first coating layer and the second coating layer are both polyurethane layers containing modified glass beads.

[0047] The thermoplastic polymer is formed by mixing TPE and TPU in a weight ratio of 3:1.

[0048] The length of the cowhide fiber is 0.1 mm, and the fineness of the cowhide fiber is 0.8 tex.

[0049] The PC-ABS copolymer is composed of a melt index of 3g / 10min and a density of 1.20g / cm 3 PC with a melt index of 1g / 10min and a density of 1.01g / cm 3 ABS is mixed in a weight ratio of 5:1.

[0050] The ethylene-vinyl acetate copolymer is a mixture of ethylene and vinyl acetate in a weight ratio of 1:2.0. The ethylene-vinyl acetate copolymer has a melt index of 10 g / 10 min and a density of 0.928 g / cm 3 .

[0051] The weight average molecular weight of the polyhydroxyalkanoate is 200,000, the melt index of the polyhydroxyalkanoate is 15 g / 10 min, and the density is 1.20 g / cm 3 ; The water content of the polyhydroxyalkanoate is 0.5wt%.

[0052] The preparation process of the wear-resistant dot pattern luggage case shell is the same as that of Example 1.

[0053] Example 3

[0054] A wear-resistant polka-dot luggage case shell comprises a shell having at least three layers, namely, a first coating layer, a substrate layer, and a second coating layer, from the inside out. The substrate layer is provided with a plurality of wear-resistant dots, which constitute the outer surface pattern of the shell. The substrate layer is composed of the following raw materials in parts by weight: 135 parts of a thermoplastic polymer, 100 parts of an ethylene-vinyl acetate copolymer, 40 parts of maleic anhydride, 20 parts of tetraethyl silicate, 30 parts of a PC-ABS copolymer, 50 parts of kraft fiber, and 20 parts of a polyhydroxyalkanoate.

[0055] The thickness of the first coating layer or the second coating layer is 0.3 times the thickness of the substrate layer; the first coating layer and the second coating layer are both polyurethane layers containing modified glass beads.

[0056] The thermoplastic polymer is formed by mixing TPE and TPU in a weight ratio of 5:1.

[0057] The length of the cowhide fiber is 0.5 mm, and the fineness of the cowhide fiber is 1.5 tex.

[0058] The PC-ABS copolymer is composed of a melt index of 5g / 10min and a density of 1.22g / cm 3 PC with a melt index of 3g / 10min and a density of 1.04g / cm3 ABS is mixed in a weight ratio of 8:1.

[0059] The ethylene-vinyl acetate copolymer is a mixture of ethylene and vinyl acetate in a weight ratio of 1:4.5. The ethylene-vinyl acetate copolymer has a melt index of 15 g / 10 min and a density of 0.957 g / cm 3 .

[0060] The weight average molecular weight of the polyhydroxyalkanoate is 300,000, the melt index of the polyhydroxyalkanoate is 20 g / 10 min, and the density is 1.25 g / cm 3 ; The water content of the polyhydroxyalkanoate is 1wt%.

[0061] The preparation process of the wear-resistant dot pattern luggage case shell is the same as that of Example 1.

[0062] Comparative Example 1

[0063] The difference between this comparative example and Example 1 is that the amount of the cowhide fiber used is 15 parts by weight and the length is 2 mm.

[0064] Comparative Example 2

[0065] The difference between this comparative example and Example 1 is that the thickness of the first coating layer and the second coating layer is 0.4 times the thickness of the substrate layer.

[0066] Comparative Example 3

[0067] The difference between this comparative example and Example 1 is that the first coating layer and the second coating layer are polyurethane materials without modified glass beads.

[0068] Comparative Example 4

[0069] The difference between this comparative example and Example 1 is that all the raw materials are added together into a twin-screw extruder for mixing, extrusion, granulation and injection molding without adding them step by step.

[0070] Performance Testing

[0071] The wear-resistant polka dot pattern luggage cases prepared in Examples 1-3 and Comparative Examples 1-4 were tested for their antifouling properties, degradation properties, and notched impact strength.

[0072] Antifouling test: Drop a liquid (5-10 mL) onto the luggage surface and let it sit for 10-30 minutes. Use a contact angle tester to assess the spread of the liquid on the surface.

[0073] Wear test: Use a Taber abrader to rub the luggage case with a specific load (e.g., 500 g) and a grinding wheel (H18), and record the wear in mg.

[0074] Notched impact strength: Using ISO 179-1eA standard simply supported beam, room temperature conditions are 23±2℃, low temperature conditions are -30±2℃, placed at low temperature of -30℃ for 6 hours, and then tested in an environment of -30℃.

[0075] The luggage shell materials prepared in Examples 1-3 and Comparative Examples 1-4 were injection molded into 20-inch luggage. Then, according to the test requirements of "QBT2155-2018 Travel Bags", drop performance tests and roller impact performance tests were performed to observe the cracking / denting of the luggage shell.

[0076] The test results are shown in Table 1 below:

[0077] Table 1 Impact toughness test data

[0078]

[0079] It can be seen from Table 1 above that compared with Example 1, the contact angle, wear amount, and impact toughness test results of Comparative Example 1 are all poor, indicating that the controlled cowhide fiber dosage, length, and fineness meet the production requirements. After processing, the retained length of the cowhide fiber tends to the critical optimal length, and it has lower warpage and better dimensional stability, which helps to increase the fiber content and mechanical properties, so that the suitcase shell has higher impact strength, and at the same time can reduce the warpage of the suitcase shell, thereby improving its pressure resistance and crack resistance.

[0080] Compared with Example 1, although the contact angle of Comparative Example 2 is improved, the wear and impact toughness test results are poor. In addition, the prepared luggage shell cracks but does not dent after the drop and roll tests, indicating that the appropriate coating thickness is beneficial to the pressure resistance and crack resistance of the luggage shell.

[0081] Compared with Example 1, although the impact toughness of Comparative Example 3 is improved, its antifouling and wear resistance are poor, indicating that the polyurethane material coating containing modified glass beads has a significant promoting effect on the antifouling and wear resistance of the luggage box shell.

[0082] Compared with Example 1, the antifouling, wear resistance, drop and roll test results of Comparative Example 4 are all poor, indicating that mixing the raw materials in batches helps to improve the impact strength of the suitcase shell and reduce the warping of the suitcase shell, thereby improving its pressure resistance and crack resistance.

[0083] Under the premise that no conflict occurs, those skilled in the art may freely combine and superimpose the above-mentioned additional technical features.

[0084] It will be understood that the present invention is described by way of some embodiments, and it will be appreciated by those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are intended to be protected by the present invention.

Claims

1. Wear-resistant polka dot pattern luggage shell, characterized by: The invention comprises a shell, which is provided with at least three layers, including a first coating layer, a substrate layer, and a second coating layer from the inside out. The substrate is provided with a plurality of wear-resistant dots, and the plurality of wear-resistant dots constitute the texture of the outer surface of the shell. The substrate layer is composed of the following raw materials in parts by weight, including 120-135 parts of thermoplastic polymer, 80-100 parts of ethylene-vinyl acetate copolymer, 30-40 parts of maleic anhydride, 10-20 parts of tetraethyl silicate, 20-30 parts of PC-ABS copolymer, 20-50 parts of kraft fiber, and 10-20 parts of polyhydroxyalkanoate.

2. The wear-resistant polka dot pattern luggage shell according to claim 1, characterized in that: The thickness of the first coating layer or the second coating layer is 0.1-0.3 times the thickness of the substrate layer; the first coating layer and the second coating layer are both polyurethane material layers containing modified glass beads.

3. The wear-resistant polka dot pattern luggage shell according to claim 1, characterized in that: The thermoplastic polymer is formed by mixing TPE and TPU in a weight ratio of 3-5:

1.

4. The wear-resistant polka dot pattern luggage shell according to claim 1, characterized in that: The length of the cowhide fiber is 0.1-0.5 mm, and the fineness of the cowhide fiber is 0.8-1.5 tex.

5. The wear-resistant polka dot pattern luggage shell according to claim 1, characterized in that: The PC-ABS copolymer is composed of a melt index of 3-5 g / 10 min and a density of 1.20-1.22 g / cm 3 PC with a melt index of 1-3g / 10min and a density of 1.01-1.04g / cm 3 ABS is mixed in a weight ratio of 5-8:

1.

6. The wear-resistant polka dot pattern luggage shell according to claim 1, characterized in that: The ethylene-vinyl acetate copolymer is a mixture of ethylene and vinyl acetate in a weight ratio of 1:2.0-4.

5. The ethylene-vinyl acetate copolymer has a melt index of 10-15 g / 10 min and a density of 0.928-0.957 g / cm 3 .

7. The wear-resistant polka dot pattern luggage shell according to claim 1, characterized in that: The weight average molecular weight of the polyhydroxyalkanoate is 200,000-300,000, the melt index of the polyhydroxyalkanoate is 15-20 g / 10 min, and the density is 1.20-1.25 g / cm 3 ; The water content of the polyhydroxyalkanoate is 0.5-1wt%.

8. The preparation process of the wear-resistant dot pattern luggage shell is characterized by: The following steps are involved: S1. Weighing raw materials by weight, first putting the raw materials thermoplastic polymer, PC-ABS copolymer, and part of maleic anhydride into a twin-screw extruder containing an organic solvent for mixing, then adding the raw materials ethylene-vinyl acetate copolymer, polyhydroxyalkanoate, and the remaining maleic anhydride, mixing for a period of time, and finally adding kraft fiber, continuing to mix, followed by extrusion and granulation to obtain a mixture; S2. Put the mixture obtained in step S1 into an injection molding machine, injection-molding at a temperature of 150-180° C., and cooling to obtain a substrate layer; S3. Apply the polyurethane material containing modified glass beads on the base material layer obtained in step S2 and cure it to obtain a wear-resistant polka dot pattern suitcase shell.

9. The process for preparing the wear-resistant polka dot pattern luggage shell according to claim 8, characterized in that: The preparation of the polyurethane material containing modified glass beads includes adding xylene diisocyanate and polypropylene glycol in a certain proportion into a three-necked flask, stirring at a constant temperature of 50°C in an oil bath for 1 hour, then heating to 80°C and continuing stirring for 2 hours to generate a polyurethane prepolymer; then adding 1,4-butanediol, phosphate ester, and modified glass beads to the prepolymer, continuing stirring and heating for 3 hours to obtain the polyurethane material containing modified glass beads.

10. The process for preparing the wear-resistant polka dot pattern luggage shell according to claim 9, characterized in that: The modified glass beads are composed of glass beads and polycatecholamine.

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