Jacquard vamp material based on bio-based degradable polylactic acid (PLA) and preparation method thereof

Abstract

The invention discloses a jacquard vamp material based on bio-based degradable polylactic acid (PLA) and a preparation method thereof, and relates to the technical field of shoe materials. The jacquard vamp material is of a three-layer jacquard structure formed by integrally weaving PLA composite filaments through a jacquard warp knitting machine. The PLA composite filament is prepared from the following raw materials in parts by weight: 80-95 parts of polylactic acid (PLA) slices, 5-15 parts of poly (butylene adipate / terephthalate) (PBAT), 3-8 parts of a flexibilizer, 1-3 parts of a compatilizer, 0.5-2 parts of an anti-hydrolysis agent and 0.5-1.5 parts of a lubricant. According to the invention, the bio-based PLA is used as a main raw material and is matched with degradable auxiliaries such as PBAT, so that the whole vamp material can be completely biodegraded under a composting condition, the problem of environmental pollution of a traditional vamp is fundamentally solved, and meanwhile, through blending modification of PBAT and the flexibilizer, the flexibility and impact resistance of the PLA material are remarkably improved, and the vamp material has good application prospects. The requirements of the vamp material on softness, wear resistance and durability can be met.

Description

Technical Field

[0001] This invention belongs to the field of footwear technology, specifically to a jacquard upper material based on bio-based biodegradable polylactic acid (PLA) and its preparation method. Background Technology

[0002] With increasing global environmental awareness, the footwear and apparel industry has an increasingly urgent need for sustainable and environmentally friendly materials. Traditional shoe upper materials mostly use synthetic fibers derived from petrochemicals, such as polyester (PET) and nylon (PA). These materials are difficult to degrade in the natural environment and cause long-term "white pollution" after being discarded.

[0003] Polylactic acid (PLA) is a biodegradable polyester derived from renewable plants such as corn and cassava. Its waste can ultimately decompose into carbon dioxide and water under specific composting conditions, making it environmentally friendly. However, pure PLA materials have some inherent drawbacks, such as high brittleness, insufficient toughness, poor thermal stability, and excessively rapid hydrolysis, which limit its application in jacquard shoe uppers that require high softness, high abrasion resistance, and complex woven structures.

[0004] Jacquard uppers are highly favored for their ability to create complex, precise, one-piece molded three-dimensional patterns and functional zones through jacquard weaving. Currently, applying PLA materials to jacquard uppers faces two major challenges: firstly, the flexibility and elasticity of PLA fibers are insufficient to meet the mechanical performance requirements of upper materials; secondly, during the jacquard warp knitting process, the coefficient of friction and static electricity of PLA filaments can affect weaving efficiency and fabric quality.

[0005] Therefore, developing a jacquard shoe upper material and its preparation process that retains the biodegradable properties of PLA while possessing excellent mechanical properties and weavability has significant market value and environmental significance.

[0006] The information disclosed above in this background section is only for enhancing the understanding of the background technology of this invention, and therefore may include prior art that is not known to those skilled in the art. Summary of the Invention

[0007] The purpose of this invention is to provide a PLA jacquard shoe upper material with good flexibility, high strength, and complete biodegradability, and its preparation method.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a jacquard upper material based on bio-based biodegradable polylactic acid (PLA), wherein the jacquard upper material is a three-layer jacquard structure integrally woven from PLA composite filaments using a jacquard warp knitting machine; the PLA composite filaments are made from the following raw materials in parts by weight: 80-95 parts of polylactic acid (PLA) chips, 5-15 parts of polybutylene adipate / terephthalate (PBAT), 3-8 parts of toughening agent, 1-3 parts of compatibilizer, 0.5-2 parts of anti-hydrolysis agent, and 0.5-1.5 parts of lubricant.

[0009] Preferably, the toughening agent is polypropylene carbonate (PPC) or polyhydroxyalkanoate (PHA); the compatibilizer is maleic anhydride-grafted PLA; the anti-hydrolysis agent is a carbodiimide anti-hydrolysis agent; and the lubricant is calcium stearate or ethylene bis-stearamide.

[0010] Preferably, the three-layer jacquard structure includes a skin-friendly surface layer, a middle connecting layer, and an outer bottom layer; the surface layer uses 75D / 72F PLA composite filaments, forming a soft and smooth skin-friendly layer with a densely woven chain structure; the connecting layer uses 100D / 48F PLA composite filaments, forming an elastic support structure with a weft plain knit structure; and the bottom layer uses 150D / 36F PLA composite filaments, forming a wear-resistant and stable outer layer structure with a warp plain knit structure.

[0011] The present invention also provides a method for preparing the above-described bio-based biodegradable polylactic acid (PLA)-based jacquard shoe upper material, comprising the following steps:

[0012] Step 1, Raw material mixing and drying: Weigh each raw material according to the ratio, place them in a high-speed mixer and mix evenly; then dry the mixture in a vacuum oven at 80-90℃ for 4-6 hours to make its moisture content less than 50ppm;

[0013] Step 2, melt blending and extrusion: The dried mixture is fed into a twin-screw extruder for melt blending, extrusion, cooling, and pelletizing to obtain PLA / PBAT composite masterbatch;

[0014] Step 3, melt spinning: The above composite masterbatch is fed into a screw extrusion spinning machine for melt spinning. After metering, spinneret extrusion, side blowing cooling, oiling, drawing and winding, PLA composite filament is obtained.

[0015] Step 4, Jacquard warp knitting: The three specifications of PLA composite filaments, namely 75D / 72F, 100D / 48F and 150D / 36F, are used as yarns and threaded into different guide bars of the Jacquard warp knitting machine. They are knitted in one piece according to the preset three-layer structure pattern program to obtain the Jacquard shoe upper fabric.

[0016] Step 5, finishing: The woven jacquard upper fabric is pre-shaped, dyed and set in sequence to finally obtain the jacquard upper material based on bio-based biodegradable polylactic acid (PLA).

[0017] Preferably, in step 2, the temperatures of each section of the extruder are set as follows: Zone 1 165-170℃, Zone 2 170-175℃, Zone 3 175-180℃, Zone 4 180-185℃, and the die head 185-190℃.

[0018] Preferably, in step 3, the spinning temperature is 190-210℃, the draw ratio is 3.0-4.0 times, and the winding speed is 3000-4000m / min.

[0019] Preferably, in step 4, the specific method of jacquard weaving is as follows: using 150D / 36F PLA composite filaments to weave the bottom layer through GB1 comb bar, using 100D / 48F PLA composite filaments to weave the connecting layer through GB2 comb bar, and using 75D / 72F PLA composite filaments to weave the top layer through jacquard comb bar.

[0020] Preferably, in step 5, the pre-setting temperature is 120-130℃ and the time is 30-60 seconds; a low-temperature disperse dye is used, and the dyeing temperature is 95-105℃; the setting temperature is 110-120℃ and the time is 40-60 seconds.

[0021] The present invention also provides a process for manufacturing shoe uppers using the above-described bio-based biodegradable polylactic acid (PLA)-based jacquard upper material, comprising the following steps:

[0022] Step 1, 3D Design: Use computer-aided design software to create a 3D model of the shoe upper and the corresponding jacquard pattern file;

[0023] Step 2, Jacquard weaving: Import the above pattern file into the Jacquard warp knitting machine, and use the PLA composite filament to weave an upper sheet that corresponds to the three-dimensional shape of the shoe upper;

[0024] Step 3, Laser Cutting: The woven shoe upper sheet is precisely cut using a laser cutting machine. The high temperature of the laser melts the cut edges simultaneously, preventing them from coming apart.

[0025] Step 4, Upper stitching and assembly: Assemble the cut upper parts with the necessary lining and logo by sewing or high-frequency welding to form a complete upper;

[0026] Step 5, Sole Assembly: The assembled upper is combined with the sole made of bio-based biodegradable material by adhesive bonding or injection molding to obtain a complete shoe.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. This invention uses bio-based PLA as the main raw material, combined with biodegradable additives such as PBAT, so that the entire shoe upper material can be completely biodegraded under composting conditions, fundamentally solving the environmental pollution problem of traditional shoe uppers. At the same time, through the blending modification of PBAT and toughening agents, the flexibility and impact resistance of PLA material are significantly improved, enabling it to meet the requirements of shoe upper materials for softness, abrasion resistance and durability.

[0029] 2. The three-layer jacquard structure designed in this invention realizes the functionality of different areas of the shoe upper. The surface layer is soft and skin-friendly, the connecting layer provides dynamic elastic support, and the bottom layer enhances wear resistance and stability, making the overall shoe upper lightweight, breathable, and with good fit.

[0030] 3. This invention improves the spinnability of PLA filaments and their weaving performance in Jacquard warp knitting by adding lubricants and compatibilizers, thereby increasing production efficiency and fabric quality. The finishing process is gentle and effectively controls the performance changes of PLA materials at high temperatures.

[0031] 4. This invention successfully solves the problem that pure PLA material is brittle and difficult to use for complex shoe upper weaving. The resulting shoe upper material has excellent mechanical properties, a comfortable wearing experience, and is completely biodegradable, which is in line with the trend of green and environmentally friendly sustainable development. Furthermore, it provides a complete set of technical solutions from material modification, fiber preparation, fabric weaving to final product manufacturing, and has extremely high industrial transformation value. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0033] Figure 1 This is a schematic diagram of the three-layer Jacquard structure of the present invention;

[0034] Figure 2 This is a flowchart illustrating the preparation process of the jacquard shoe upper material of this invention.

[0035] Figure 3 This is a diagram illustrating the manufacturing process of the jacquard shoe upper according to the present invention.

[0036] In the picture:

[0037] 1. Top layer; 2. Connecting layer; 3. Bottom layer. Detailed Implementation

[0038] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0039] Example 1

[0040] Preparation of PLA composite filaments:

[0041] Prepare the following raw materials: 85 parts PLA slices, 10 parts PBAT, 5 parts toughening agent PHA, 2 parts compatibilizer maleic anhydride grafted PLA, 1 part carbodiimide anti-hydrolysis agent, and 1 part lubricant calcium stearate.

[0042] Mix the above raw materials evenly and vacuum dry them at 85°C for 5 hours to reduce their moisture content to less than 50 ppm.

[0043] The dried mixture is fed into a twin-screw extruder for melt blending, extrusion, cooling, and pelletizing to obtain PLA / PBAT composite masterbatch. The extruder temperatures are set as follows: Zone 1 168℃, Zone 2 173℃, Zone 3 178℃, Zone 4 183℃, and Die Head 188℃.

[0044] The composite masterbatch was fed into a spinning machine and melt-spun at 195°C. After 3.5 times draw and a winding speed of 3500 m / min, PLA composite filaments of three specifications, namely 75D / 72F, 100D / 48F, and 150D / 36F, were obtained.

[0045] Preparation of Jacquard shoe upper material:

[0046] The three specifications of PLA composite filaments are knitted on a Karl Mayer RJPC4-F jacquard warp knitting machine. Specifically, GB1 guide bars are woven with 150D / 36F filaments to form the bottom layer, creating a wear-resistant and stable outer layer structure using a warp plain weave. GB2 guide bars are woven with 100D / 48F filaments to form the connecting layer, creating an elastic support structure using a weft plain weave. The jacquard guide bars are woven with 75D / 72F filaments to form the surface layer, creating a soft and smooth skin-friendly layer using a dense chain weave. This results in a three-dimensional jacquard structure with breathable holes and reinforcing support strips.

[0047] The woven fabric was sequentially pre-shaped, dyed, and finished to obtain a jacquard shoe upper material based on bio-based biodegradable polylactic acid (PLA). The pre-shaped temperature was 125℃ for 45 seconds; the dyeing temperature was 100℃; and the finishing temperature was 115℃ for 50 seconds.

[0048] Example 2

[0049] The difference from Example 1 is as follows:

[0050] Raw material ratio: 90 parts PLA chips, 5 parts PBAT, 4 parts toughening agent PPC, 1.5 parts compatibilizer, 1 part anti-hydrolysis agent, and 1 part lubricant ethylene bis-stearamide.

[0051] The preparation processes for PLA composite filaments and jacquard shoe upper materials are the same as those in Example 1.

[0052] Comparative Example 1: Pure PLA

[0053] Spinning and weaving are done using 100% PLA chips.

[0054] The process parameters are the same as in Example 1.

[0055] Comparative Example 2: High PBAT Content

[0056] The difference from Example 1 is as follows:

[0057] Raw material ratio: 70 parts PLA chips, 25 parts PBAT, 3 parts compatibilizer, and other additives as in Example 1. The preparation processes of PLA composite filaments and jacquard shoe upper materials are the same as in Example 1. This comparative example is used to investigate the effect of excessive PBAT content on the rigidity and heat resistance of the materials.

[0058] Comparative Example 3: No compatibilizer

[0059] The difference from Example 1 is as follows:

[0060] Raw material ratio: 85 parts PLA chips, 10 parts PBAT, 5 parts PHA, no compatibilizer added, 1 part anti-hydrolysis agent, 1 part lubricant.

[0061] The preparation processes for PLA composite filaments and jacquard upper materials are the same as in Example 1. This comparative example is used to verify the key role of the compatibilizer in the blend system.

[0062] Comparative Example 4: Commercially available PET shoe uppers

[0063] The comparison was made using commercially available ordinary polyester (PET) jacquard shoe upper material.

[0064] The system performance of the shoe upper materials obtained in the examples and comparative examples was tested, and the results are shown in the table below.

[0065]

[0066]

[0067] As can be seen from the above, in terms of mechanical properties, compared with Comparative Example 1, the fracture, tear, and puncture strength of Examples 1 and 2 are significantly higher than those of Comparative Example 1, while the bending stiffness is significantly reduced. This proves that the addition of PBAT and toughening agent effectively improves the toughness and resistance to damage of PLA, making it more flexible and fully meeting the requirements of shoe uppers.

[0068] Compared to Comparative Example 2, Example 2 exhibits the lowest bending stiffness (i.e., the softest), but its breaking strength and bursting strength are both lower than those of Example 1, and its thermal shrinkage is higher. This indicates that excessive PBAT sacrifices the material's strength and dimensional stability, while the formulation of Example 1 achieves the optimal balance between toughness and strength.

[0069] Compared with Comparative Example 3, the mechanical properties of Comparative Example 3 are all between those of Example 1 and Comparative Example 1, but are significantly inferior to those of Example 1. This confirms the crucial role of compatibilizer in improving the interfacial compatibility between PLA and PBAT / PHA. The lack of compatibilizer will lead to uneven stress transmission and easy damage to the material.

[0070] Although the mechanical properties of Examples 1 and 2 are slightly lower than those of commercially available PET, they are very close and fully meet the standards for use as shoe upper materials.

[0071] In terms of comfort and durability, all PLA-based materials exhibit significantly higher moisture permeability than PET. This is because PLA molecular chains contain polar ester groups, which readily adsorb and transfer water molecules, giving the shoe upper excellent breathability and moisture-wicking properties. The strength retention rates after hydrolysis aging in Examples 1 and 2 are over 82%, while Comparative Example 1 only retains 45%, indicating extremely poor durability. This invention, by adding anti-hydrolysis agents and compatibilizers, greatly improves the material's lifespan in humid and hot environments. The lower retention rate in Comparative Example 3 further demonstrates the importance of anti-hydrolysis agents and compatibilizers.

[0072] In terms of processing performance, the filament of Comparative Example 1 was highly brittle, resulting in an extremely high breakage rate during weaving, making normal production almost impossible. Examples 1 and 2, through modification, reduced the breakage rate to an extremely low level, demonstrating their excellent weavability. The addition of lubricant effectively reduced friction between the fibers and the yarn guide components.

[0073] In terms of environmental performance, all PLA-based materials exhibit excellent biodegradability, while PET is non-degradable.

[0074] In summary, this invention has successfully prepared a biodegradable jacquard shoe upper material with excellent comprehensive performance. While maintaining the inherent environmental friendliness and high moisture permeability of PLA, it fundamentally overcomes the three major technical bottlenecks of pure PLA—high brittleness, poor hydrolysis resistance, and difficulty in weaving—through scientific formulation and structural design. Its overall performance is comparable to traditional PET shoe uppers, providing a practical solution for achieving green and sustainable development in the footwear and apparel industry.

[0075] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0076] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0077] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A jacquard shoe upper material based on bio-based biodegradable polylactic acid (PLA), characterized in that: The jacquard upper material is a three-layer jacquard structure woven in one piece by a jacquard warp knitting machine from PLA composite filaments; the PLA composite filaments are made from the following raw materials in parts by weight: 80-95 parts of polylactic acid (PLA) chips, 5-15 parts of polybutylene adipate / terephthalate (PBAT), 3-8 parts of toughening agent, 1-3 parts of compatibilizer, 0.5-2 parts of anti-hydrolysis agent, and 0.5-1.5 parts of lubricant.

2. The jacquard upper material based on bio-based biodegradable polylactic acid (PLA) according to claim 1, characterized in that: The toughening agent is polypropylene carbonate (PPC) or polyhydroxyalkanoate (PHA); the compatibilizer is maleic anhydride-grafted PLA; the anti-hydrolysis agent is a carbodiimide anti-hydrolysis agent; and the lubricant is calcium stearate or ethylene bis-stearamide.

3. The jacquard upper material based on bio-based biodegradable polylactic acid (PLA) according to claim 1, characterized in that: The three-layer jacquard structure includes a skin-friendly surface layer (1), a middle connecting layer (2), and an outer bottom layer (3). The surface layer uses 75D / 72F PLA composite filaments, which form a soft and smooth skin-friendly layer with a densely woven chain structure. The connecting layer uses 100D / 48F PLA composite filaments, which form an elastic support structure with a weft plain knit structure. The bottom layer uses 150D / 36F PLA composite filaments, which form a wear-resistant and stable outer layer structure with a warp plain knit structure.

4. A method for preparing a jacquard shoe upper material based on bio-based biodegradable polylactic acid (PLA) as described in any one of claims 1-3, characterized in that, Includes the following steps: Step 1, Raw material mixing and drying: Weigh each raw material according to the ratio, place them in a high-speed mixer and mix evenly; then dry the mixture in a vacuum oven at 80-90℃ for 4-6 hours to make its moisture content less than 50ppm; Step 2, melt blending and extrusion: The dried mixture is fed into a twin-screw extruder for melt blending, extrusion, cooling, and pelletizing to obtain PLA / PBAT composite masterbatch; Step 3, melt spinning: The above composite masterbatch is fed into a screw extrusion spinning machine for melt spinning. After metering, spinneret extrusion, side blowing cooling, oiling, drawing and winding, PLA composite filament is obtained. Step 4, Jacquard warp knitting: The three specifications of PLA composite filaments, namely 75D / 72F, 100D / 48F and 150D / 36F, are used as yarns and threaded into different guide bars of the Jacquard warp knitting machine. They are knitted in one piece according to the preset three-layer structure pattern program to obtain the Jacquard shoe upper fabric. Step 5, finishing: The woven jacquard upper fabric is pre-shaped, dyed and set in sequence to finally obtain the jacquard upper material based on bio-based biodegradable polylactic acid (PLA).

5. The method for preparing the Jacquard upper material based on bio-based biodegradable polylactic acid (PLA) according to claim 4, characterized in that: In step 2, the temperatures of each section of the extruder are set as follows: Zone 1 165-170℃, Zone 2 170-175℃, Zone 3 175-180℃, Zone 4 180-185℃, and the die head 185-190℃.

6. The method for preparing the jacquard shoe upper material based on bio-based biodegradable polylactic acid (PLA) according to claim 4, characterized in that: In step 3, the spinning temperature is 190-210℃, the draw ratio is 3.0-4.0 times, and the winding speed is 3000-4000m / min.

7. The method for preparing the jacquard shoe upper material based on bio-based biodegradable polylactic acid (PLA) according to claim 4, characterized in that: In step 4, the specific method of jacquard weaving is as follows: 150D / 36F PLA composite filaments are used to weave the bottom layer through GB1 comb, 100D / 48F PLA composite filaments are used to weave the connecting layer through GB2 comb, and 75D / 72F PLA composite filaments are used to weave the top layer through jacquard comb.

8. The method for preparing the jacquard shoe upper material based on bio-based biodegradable polylactic acid (PLA) according to claim 4, characterized in that: In step 5, the pre-formed temperature is 120-130℃ and the time is 30-60 seconds; Low-temperature disperse dyes are used, with a dyeing temperature of 95-105℃; the setting temperature is 110-120℃, and the time is 40-60 seconds.

9. A process for manufacturing shoe uppers using the jacquard upper material based on bio-based biodegradable polylactic acid (PLA) as described in any one of claims 1-3, characterized in that, Includes the following steps: Step 1, 3D Design: Use computer-aided design software to create a 3D model of the shoe upper and the corresponding jacquard pattern file; Step 2, Jacquard weaving: Import the above pattern file into the Jacquard warp knitting machine, and use the PLA composite filament to weave an upper sheet that corresponds to the three-dimensional shape of the shoe upper; Step 3, Laser Cutting: The woven shoe upper sheet is precisely cut using a laser cutting machine. The high temperature of the laser melts the cut edges simultaneously, preventing them from coming apart. Step 4, Upper stitching and assembly: Assemble the cut upper parts with the necessary lining and logo by sewing or high-frequency welding to form a complete upper; Step 5, Sole Assembly: The assembled upper is combined with the sole made of bio-based biodegradable material by adhesive bonding or injection molding to obtain a complete shoe.

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