Preparation method of polypropylene recyclable outdoor fabric

Abstract

The invention discloses a preparation method of a polypropylene recyclable outdoor fabric. The preparation method comprises the following steps: (1) preparing a polypropylene fabric; (2) design of a polypropylene molecular structure of an outdoor fabric and preparation of the outdoor fabric; (3) designing and preparing a polypropylene film; and (4) compounding the polypropylene fabric and the polypropylene film. According to the invention, deep research is carried out from multiple dimensions. The method comprises the following steps: firstly, optimizing a fabric weave structure of dope-dyed polypropylene fibers, screening out a structure which is most suitable for waterproof and moisture permeable application, and further improving the fabric performance by regulating and controlling weaving process parameters; aiming at the defects of the fabric in the aspects of light resistance and waterproofness, a multi-component light stabilizer and a waterproof agent are introduced to form a synergistic finishing system, so that the comprehensive performance of the fabric is remarkably improved. In addition, waterproof and moisture permeable modification of the polypropylene film is researched, and an environment-friendly adhesive formula and a laminating process are further optimized, so that the aim of 100% recycling of the polypropylene fabric and the film is fulfilled.

Description

Technical Field

[0001] The invention belongs to the field of fabric preparation, and particularly relates to a method for preparing a polypropylene recyclable outdoor fabric. Background Art

[0002] As consumers' environmental awareness increases, the concept of "sustainable fashion" has gradually gained popularity, and more and more consumers prefer environmentally friendly and recyclable materials when choosing textiles. This trend has prompted the textile industry to accelerate the research and development of green materials to meet consumers' environmental protection needs. This shift in market demand has prompted textile manufacturers to innovate in source materials and production processes, shift to environmentally friendly and recyclable materials, and fully promote the green upgrade of the textile industry chain. Although there are some recyclable fiber materials on the market, such as polyester fiber (PET) and nylon, there are certain limitations in the recycling process. The recycling of PET and nylon usually requires multiple steps, including washing, separation, crushing, melting and other steps, which consume a lot of energy and water resources. PET and nylon will have a certain degree of chemical degradation every time they are recycled, resulting in polymer chain breakage, reduced mechanical properties and quality of the fiber, and it is difficult to restore to the original state. In addition, many textiles are blended with PET or nylon and other fibers (such as cotton, spandex, etc.). These multi-component materials are difficult to effectively separate during recycling, which increases the difficulty of recycling and also leads to reduced purity and performance of the final recycled materials. Although chemical recycling (such as chemical depolymerization) can solve the partial degradation problem of PET and nylon and make the recycled materials close to the original properties, the process is complex, costly and uses chemical solvents, resulting in high energy consumption and increased carbon footprint, and may produce harmful by-products.

[0003] Polypropylene materials are gradually becoming an important development trend for outdoor fabrics in the future due to their light weight, chemical resistance, excellent mechanical properties and fully recyclable characteristics. Compared with other recyclable materials, the recycling process of polypropylene is simpler and more efficient, and it can be recycled under low energy consumption conditions. In addition, polypropylene shows significant advantages in terms of light weight and chemical resistance, and is particularly suitable for outdoor clothing and textile applications. Although polypropylene has great application potential in the field of fiber textiles and outdoor clothing, it still faces technical difficulties such as poor color fastness and poor weather resistance in the process of textile applications. Therefore, further innovation in material properties and fiber processing technology is particularly critical. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing a polypropylene recyclable outdoor fabric, and to conduct in-depth research from multiple dimensions to address the performance deficiencies and recycling bottlenecks of existing polypropylene materials in practical applications. First, the polypropylene polymers of the developed fabrics and membranes are structurally designed and developed respectively, and further in-depth research is conducted from the recyclability of the composite fabrics to develop outdoor composite fabrics suitable for melt spinning during the recycling process. At the same time, the fabric structure of the solution-dyed polypropylene fiber is optimized to screen out the most suitable structure for waterproof and breathable applications, and the fabric performance is further improved by regulating the weaving process parameters. In view of the deficiencies of the fabric in terms of light resistance and waterproofness, multi-component light stabilizers and waterproofing agents are introduced to form a synergistic finishing system, which significantly improves its comprehensive performance. In addition, the waterproof and breathable modification of the polypropylene film is studied, and then the environmentally friendly adhesive formula and lamination process are further optimized. This design not only improves the functionality of the composite fabric during use, but also realizes the "waste into treasure" of waste products generated after the use of ready-made clothes, providing a research and development direction for the full recycling of high-quality recycled fibers, helping to promote the development of the circular economy.

[0005] In order to solve the above technical problems, the following technical solutions are adopted:

[0006] A method for preparing a polypropylene recyclable outdoor fabric, characterized by comprising the following steps:

[0007] (1) Design of polypropylene molecular structure for outdoor fabrics and its fabric preparation

[0008] The polypropylene molecular weight distribution index (PDI) is designed to be 2.3-2.5, the number average molecular weight (Mn) is 50,000-100000 g / mol, the weight average molecular weight (Mw) is 100000-200000 g / mol; the melt index (MFI) is 18 g / 10min (230°C, 2.16kg); the polypropylene fabric is prepared by using solution-dyed polypropylene fiber as raw material, determining the organization structure and weaving process parameters;

[0009] (2) Light-resistant and waterproof finishing of polypropylene fabric

[0010] Firstly, the polypropylene fabric is placed in a light stabilizer for light resistance finishing, and then the polypropylene fabric is waterproofed with a waterproof finishing agent to obtain the finished polypropylene fabric;

[0011] (3) Design and preparation of polypropylene film

[0012] The molecular weight distribution index (PDI) is about 2.2-2.6, the number average molecular weight (Mn) is 70000-120000 g / mol, the weight average molecular weight (Mw) is 130000-250000 g / mol, and the melt index (MFI) is 12g / 10min (230°C, 2.16kg). The polypropylene melt with thermoplastic polyurethane additives is first made into a thick film by a biaxial stretching process, and then the thick film is longitudinally and transversely stretched by a stretching machine, the stretching speed is controlled to be 10mm / s-30mm / s, the stretching temperature is 150-170°C, and the polypropylene film is obtained after heat setting and cooling, and the polypropylene film is modified;

[0013] (4) Polypropylene fabric and polypropylene film composite

[0014] Adhesive is used to compound polypropylene fabric and polypropylene film, wherein the lamination temperature is 150-190°C, the adhesive layer thickness is 5-15 μm, and the lamination pressure is 0.5-1.5 MPa.

[0015] After optimization, in the step (1), the weave structure adopts plain weave, and the fabric process parameters include loom speed, warp and weft density, machine tension and weaving shrinkage, wherein the loom speed is 200-300 rpm, the warp density in the warp and weft density is 60 yarns / cm, and the weft density is 40 yarns / cm, the warp tension in the machine tension is 300-400 g / root, and the weft tension is 200-300 g / root, and the weft shrinkage in the warp direction is 8-10%, and the weft direction is 5-7%.

[0016] After optimization, in the step (2), the light stabilizer is selected from one or more of bis(2,2,6,6-tetramethyl-4-piperidinyl)sebacate, 2-(2H-benzotriazol-2-yl)-4,6-di(1-methyl-1-phenylethyl)phenol or 2-(2'-hydroxy-3',5'-di-tert-pentylphenyl)benzotriazole.

[0017] After optimization, in the step (2), the waterproof finishing agent is selected from one or more of polyether-modified siloxane, siloxane polymer or fluorine-free acrylic waterproofing agent.

[0018] After optimization, in the step (2), in the light-resistant finishing, the concentration of the light stabilizer is 50 g / L, the finishing temperature is 150° C., the setting time is 5 min, and the pH is 5; in the waterproof finishing, the concentration of the waterproof finishing agent is 20-50 g / L, the finishing temperature is 170° C., and the setting time is 2 min.

[0019] After optimization, in the step (3), the polypropylene film is modified by plasma treatment, the treatment power is set to 50-150W, and the treatment time is 30-90s.

[0020] After optimization, in the step (3), the adhesive adopts an environmentally friendly adhesive, such as water-based polyurethane adhesive, water-based acrylic adhesive or EVA hot melt adhesive; the concentration of the adhesive is 10%-20%.

[0021] After optimization, the step (4) adopts an automatic scraping mechanism to evenly apply the adhesive to the polypropylene fabric. The automatic scraping mechanism includes a machine table, a transverse screw module, a lifting screw module and a scraping assembly. The transverse screw module is installed on the horizontal frame of the machine table. The transverse screw module is connected to and drives the lifting screw module to move horizontally, thereby driving the scraping assembly to move horizontally, and the adhesive is evenly applied to the polypropylene fabric; the lifting screw module is connected to the scraping assembly through a connecting plate, and drives the scraping assembly to move up and down; the scraping assembly includes a mounting plate and a front scraper connected to the mounting plate, a rear scraper and a glue applicator, the front scraper is used to apply the adhesive to the polypropylene fabric, the rear scraper is longer than the front scraper, and is used to process the adhesive retained after the front scraper is applied, and the glue applicator is used to extrude the adhesive to the front of the front scraper.

[0022] After optimization, the glue applicator includes a storage hopper, a discharge tray and a pusher. The storage hopper is provided with a storage cavity for storing adhesive and conveying it to the discharge tray. The discharge tray is connected to the lower end of the storage hopper, and includes a pushing section and a discharging head. The pushing section is provided with a pushing cavity, and the discharging head is provided with a discharging port. The front section of the pushing cavity is connected to the discharging port, and the rear section of the pushing cavity is connected to the storage cavity; the pusher is used to push the adhesive from the pushing cavity to the discharging port. It includes a pushing cylinder and a pushing rack. The pushing cylinder is connected and drives the pushing rack to move forward and backward. The pushing rack includes a front stopper, a rear stopper and a connecting rod. The connecting rod connects the front stopper and the rear stopper. The front stopper and the rear stopper can both block the pushing cavity. The rear stopper is connected with a baffle, and the baffle is used to block the storage cavity; the pushing section is also provided with a cavity for accommodating the rear stopper and the baffle; the gluing steps of the glue applicator include:

[0023] (1) The pusher is in the initial position, the adhesive at the bottom falls into the rear section of the pusher cavity, and the front stopper blocks the front section of the pusher cavity to prevent the adhesive from flowing into the discharge port;

[0024] (2) The push cylinder is started, driving the push rack forward, the front stopper moves forward to the top of the front section of the push chamber, the rear stopper moves forward to the position of the front stopper in step (1), the baffle blocks the storage chamber, the discharge port is opened, and the adhesive in the rear section of the push chamber in step (1) is glued through the discharge port;

[0025] (3) After the gluing is completed, the push cylinder is reset, driving the push frame to retreat and reset to the position of step (1). After the reset, the adhesive at the bottom falls into the rear section of the push cavity;

[0026] (4) Repeat steps (2) and (3) when applying glue next time.

[0027] After optimization, the automatic scraping mechanism also includes a cloth presser, which is used to press the polypropylene fabric; the cloth presser includes a cloth pressing plate and a spring rod, the upper end of the cloth pressing plate is connected to the spring rod, the spring rod is connected to the cross frame of the machine, and an electromagnet is provided at the corresponding position of the machine, the electromagnet is used to adsorb the cloth pressing plate, so that the cloth pressing plate presses the fabric, and a rubber pad is provided at the bottom of the cloth pressing plate.

[0028] The above technical solution has the following beneficial effects:

[0029] 1. The present invention conducts in-depth research from multiple dimensions to address the performance deficiencies and recycling bottlenecks of existing polypropylene materials in practical applications. First, by optimizing the fabric structure of solution-dyed polypropylene fibers, the most suitable structure for waterproof and breathable applications is selected, and the fabric performance is further improved by adjusting the weaving process parameters. In view of the deficiencies of the fabric in terms of light resistance and waterproofness, multi-component light stabilizers and waterproofing agents are introduced to form a synergistic finishing system, which significantly improves its comprehensive performance. In addition, the waterproof and breathable modification of polypropylene films is studied, and the goal of 100% recyclability of polypropylene fabrics and films is achieved by further optimizing the environmentally friendly adhesive formula and lamination process.

[0030] 2. The present invention improves the water resistance, moisture permeability and tensile strength of polypropylene fabric by optimizing the tissue structure and weaving process parameters, making the process more suitable for industrial production.

[0031] 3. After waterproof finishing, the surface tension of polypropylene fabric is significantly reduced, giving it good water-repellent function; after light-resistant finishing, polypropylene fabric has good anti-ultraviolet performance.

[0032] 4. The pore size and porosity of the membrane are regulated by the stretching method, ensuring that the microporous structure provides both moisture permeability and waterproofness. In addition, the aging resistance and tear resistance of the polypropylene membrane after plasma treatment are improved, and the polypropylene membrane achieves the best balance between protection and comfort.

[0033] 5. The present invention optimizes the composite process to ensure the best balance between the air permeability and bonding strength of the fabric. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The present invention will be further described below in conjunction with the accompanying drawings:

[0035] Figure 1 It is a structural schematic diagram of the automatic scraping mechanism of the present invention;

[0036] Figure 2 It is a structural schematic diagram of the scraping and coating assembly of the present invention;

[0037] Figure 3 is a cross-sectional view of the glue applicator;

[0038] Figure 4It is a structural schematic diagram of the cloth press.

[0039] The figures are marked as follows: machine 1, cross frame 11, electromagnet 12, guide roller 2, transverse screw module 3, lifting screw module 4, scraping assembly 5, mounting plate 51, front scraper 52, rear scraper 53, glue applicator 54, storage hopper 541, storage chamber 5411, pushing section 542, pushing chamber 5421, discharging head 543, discharging port 5431, pushing cylinder 544, front stopper 545, rear stopper 546, baffle 547, connecting rod 548, bracket 549, cloth presser 6, cloth pressing plate 61, spring rod 62, rubber pad 63. DETAILED DESCRIPTION

[0040] The present invention aims to provide a method for preparing a recyclable outdoor polypropylene fabric, and conducts in-depth research from multiple dimensions. First, the polypropylene polymer of the developed fabric and film is structurally designed and developed respectively, and further in-depth research is conducted from the recyclability of the composite fabric to develop an outdoor composite fabric suitable for melt spinning during the recycling process. At the same time, the fabric structure of the solution-dyed polypropylene fiber is optimized to screen out the most suitable structure for waterproof and breathable applications, and the fabric performance is further improved by adjusting the weaving process parameters. In view of the shortcomings of the fabric in terms of light resistance and waterproofness, multi-component light stabilizers and waterproofing agents are introduced to form a synergistic finishing system, which significantly improves its comprehensive performance. In addition, the waterproof and breathable modification of the polypropylene film is studied, and then the environmentally friendly adhesive formula and lamination process are further optimized. This design not only improves the functionality of the composite fabric during use, but also realizes the "waste into treasure" of waste products generated after the use of ready-made clothes, providing a research and development direction for the full recycling of high-quality recycled fibers, helping to promote the development of the circular economy.

[0041] The present invention will be described in detail below in conjunction with specific embodiments.

[0042] Example 1

[0043] (1) Design of polypropylene molecular structure for outdoor fabrics and its fabric preparation

[0044] The designed polypropylene molecular weight distribution index (PDI) is 2.3-2.5, the number average molecular weight (Mn) is 50,000-100000 g / mol, the weight average molecular weight (Mw) is 100000-200000 g / mol; the melt index (MFI) is 18 g / 10min (230°C, 2.16 kg); the solution-dyed polypropylene fiber is used as the raw material, the organization structure adopts plain weave, the loom speed is 300 rpm, the warp density is 60 strands / cm, the weft density is 40 strands / cm, the warp tension is 400 g / strand, the weft tension is 300 g / strand, the warp shrinkage is 10% in the warp direction, and the weft shrinkage is 6% in the weft direction.

[0045] Determine the tissue structure and weaving process parameters to prepare polypropylene fabric;

[0046] (2) Light-resistant and waterproof finishing of polypropylene fabric

[0047] 1. First, put the polypropylene fabric into the light stabilizer bis (2,2,6,6-tetramethyl-4-piperidinyl) sebacate for light resistance finishing. The light stabilizer concentration is 50g / L, the finishing temperature is 150℃, the setting time is 5min, and the pH is 5.

[0048] 2. Use waterproof finishing agent polyether modified siloxane to waterproof the polypropylene fabric, the concentration of the waterproof finishing agent is 50g / L, the finishing temperature is 170°C, the setting time is 2min, and the finished polypropylene fabric is obtained;

[0049] (3) Design and preparation of polypropylene film

[0050] The molecular weight distribution index (PDI) is about 2.2-2.6, the number average molecular weight (Mn) is 70000-120000 g / mol, the weight average molecular weight (Mw) is 130000-250000 g / mol, and the melt index (MFI) is 12 g / 10 min (230°C, 2.16 kg). The polypropylene melt with thermoplastic polyurethane additives is first made into a thick film by a biaxial stretching process, and then the thick film is longitudinally and transversely stretched by a stretching machine, the stretching speed is controlled to be 20 mm / s, the stretching temperature is 160°C, and the polypropylene film is obtained after heat setting and cooling, and the polypropylene film is subjected to plasma treatment, the treatment power is set to 100 W, and the treatment time is 80 s.

[0051] (4) Polypropylene fabric and polypropylene film composite

[0052] The polypropylene fabric and the polypropylene film are compounded with water-based polyurethane adhesive, wherein the concentration of the adhesive is 20%, the lamination temperature is 170°C, the thickness of the adhesive layer is 10 μm, and the lamination pressure is 1 MPa.

[0053] Example 2

[0054] The difference from Example 1 is that the concentration of the waterproof finishing agent is 20 g / L.

[0055] Example 3

[0056] The difference from Example 1 is that the concentration of the waterproof finishing agent is 30 g / L.

[0057] The data of the polypropylene fabrics of Example 1, Example 2 and Example 3 after lightfast and waterproof finishing are shown in Table 1:

[0058]

[0059] It can be seen from Table 1 that the fabric treated with the light stabilizer initially has good anti-ultraviolet performance. The anti-ultraviolet treated fabric is treated with a waterproof finishing agent of different concentrations to obtain a waterproof fabric.

[0060] Example 4

[0061] The difference from Example 1 is that the lamination temperature is 150°C.

[0062] Example 5

[0063] The difference from Example 1 is that the lamination temperature is 190°C.

[0064] The test data of Example 1, Example 4 and Example 5 at different lamination temperatures are shown in Table 2:

[0065] Table 2

[0066]

[0067] Example 6

[0068] The difference from Example 1 is that the lamination pressure is 0.5 MPa.

[0069] Example 7

[0070] The difference from Example 1 is that the lamination pressure is 1.5 MPa.

[0071] The test data of Example 1, Example 6 and Example 7 at different lamination pressures are shown in Table 3:

[0072] Table 3

[0073]

[0074] Example 8

[0075] like Figures 1 to 4 As shown, in the above embodiment, an automatic scraping mechanism is used to evenly apply the adhesive to the polypropylene fabric. The automatic scraping mechanism includes a machine 1, a transverse screw module 3, a lifting screw module 4 and a scraping assembly 5. The machine 1 is provided with a cross frame 11 and a guide roller 2. The cross frame 11 is used to install the transverse screw module 3. The guide roller 2 is arranged at the front and rear ends of the machine 1 for conveying the fabric.

[0076] The transverse movement screw module 3 is connected to the lifting screw module 4, which is used to drive the lifting screw module 4 and the scraping component 5 to move transversely. During the transverse movement, the scraping component 5 can evenly apply the adhesive to the polypropylene fabric; the lifting screw module 4 is connected to the scraping component 5 through the connecting plate, which is used to drive the scraping component 5 to move up and down, thereby controlling the distance between the scraping component 5 and the fabric. On the one hand, it can control the thickness of the scraping, and on the other hand, it can control the scraping component 5 to enter or leave the scraping state.

[0077] The scraping assembly 5 includes a mounting plate 51 and a front scraper 52, a rear scraper 53 and a glue applicator 54 connected to the mounting plate 51. The front scraper 52 is arranged in the front and is used to apply adhesive to the polypropylene fabric. The rear scraper 53 is arranged in the rear and is longer than the front scraper 52. After the front scraper 52 is scraped, adhesive is often retained on both sides, and there are also places where the scraping is uneven. The secondary scraping with the help of the rear scraper 53 can effectively solve the above problems, thereby significantly improving the uniformity of the scraping, and then improving the composite quality. The glue applicator 54 is used to extrude the adhesive to the designed position. It is arranged in front of the front scraper 52 so that the extruded adhesive is located in front of the front scraper 52. The glue applicator 54 includes a storage hopper 541, a discharge tray and a pusher. The storage hopper 541 is provided with a storage cavity 5411 for storing adhesive and conveying it to the discharge tray. Its storage capacity can be determined according to actual production needs. The discharge tray is connected to the lower end of the storage hopper 541, which includes a pushing section 542 and a discharge head 543. A pushing cavity 5421 is provided in the pushing section 542. The pushing cavity 5421 is divided into three sections, including a front section of the pushing cavity, a rear section of the pushing cavity and a receiving cavity. The front section of the pushing cavity is connected to the discharge port 5431 of the discharge head 543, the rear section of the pushing cavity is connected to the storage cavity 5411, and the receiving cavity is used to cooperate with the pusher. The pusher is used to push the adhesive from the pushing cavity 5421 into the discharge port 5431, and includes a pushing cylinder 544 and a pushing rack. The pushing cylinder 544 is installed on the outer bracket 549, and its piston rod is connected to the pushing rack, which is used to drive the pushing rack to move back and forth in the storage cavity 5411. The pushing rack includes a front stopper 545, a rear stopper 546 and a connecting rod 548. The connecting rod 548 connects the front stopper 545 and the rear stopper 546. The front stopper 545 and the rear stopper 546 can both block the pushing cavity 5421. The rear stopper 546 is connected to a baffle 547, and the baffle 547 is used to block the storage cavity 5411. The gluing steps of the glue applicator 54 include:

[0078] (1) The pusher is in the initial position, the adhesive at the bottom falls into the rear section of the pusher cavity, and the front stopper 545 blocks the front section of the pusher cavity to prevent the adhesive from flowing into the discharge port 5431;

[0079] (2) The push cylinder 544 is started, driving the push rack forward, the front stopper 545 moves forward to the top of the front section of the push chamber, the rear stopper 546 moves forward to the position of the front stopper 545 in step (1), the baffle 547 blocks the storage chamber 5411, the discharge port 5431 is opened, and the adhesive in the rear section of the push chamber in step (1) is glued through the discharge port 5431;

[0080] (3) After the gluing is completed, the push cylinder 544 is reset, driving the push frame to retreat and reset to the position of step (1). After the reset, the adhesive at the bottom falls into the rear section of the push cavity;

[0081] (4) Repeat steps (2) and (3) when applying glue next time.

[0082] The volume between the front stopper 545 and the rear stopper 546 is the amount of adhesive extruded in a single time. By adjusting the distance between the front stopper 545 and the rear stopper 546 or adjusting the shape and size of the pushing cavity 5421, the amount of adhesive extruded in a single time can be adjusted accordingly to meet different gluing requirements and adapt to fabrics of different types and sizes.

[0083] The automatic scraping mechanism also includes a cloth presser 6, which is used to press the polypropylene fabric; the cloth presser 6 is arranged on each of the left and right sides of the horizontal frame 11, and includes a cloth pressing plate 61 and a spring rod 62. The upper end of the cloth pressing plate 61 is connected to two spring rods 62, and the spring rod 62 is connected to the horizontal frame 11, which is elastic and retractable. An electromagnet 12 is arranged at the corresponding position of the machine 1. After being started, the electromagnet 12 can adsorb the upper cloth pressing plate 61, so that the cloth pressing plate 61 can press the passing fabric. A rubber pad 63 is arranged at the bottom of the cloth pressing plate 61, and the rubber pad 63 is used to prevent the fabric from being damaged.

[0084] The gluing and scraping process of the automatic scraping mechanism includes:

[0085] (1) Turn on the electromagnet 12 to absorb the cloth pressing plate 61 and press the fabric tightly;

[0086] (2) The scraping assembly 5 is placed in the initial position and rises to a height away from scraping, and the glue applicator 54 is started once to squeeze a certain amount of adhesive onto the fabric;

[0087] (3) The lifting screw module 4 is started to drive the scraping assembly 5 down to the designed scraping height; then the transverse screw module 3 is started to drive the scraping assembly 5 to scrape the fabric laterally, so that the adhesive is evenly coated on the fabric.

[0088] (4) After scraping, the lifting screw module 4 is started to drive the scraping assembly 5 to rise to a height away from scraping; then the traverse screw module 3 is started to drive the scraping assembly 5 to return to the initial position.

[0089] (5) At the same time, the solenoid valve is closed, and the cloth pressing plate 61 rebounds upward under the action of the rebound force, and the fabric is no longer pressed tightly. At this time, the conveying mechanism is started to drive the fabric to move forward once. The distance traveled once is the fabric length corresponding to one scraping and coating.

[0090] (6) Repeat steps (1) to (5) to achieve continuous gluing and scraping operations, significantly improving the work efficiency of gluing and scraping. In addition, the process is an automated process, which reduces the difficulty of operation, improves the quality of gluing and scraping, and reduces labor cost expenditure.

[0091] The above are only specific embodiments of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent replacements or modifications made based on the present invention to solve basically the same technical problems and achieve basically the same technical effects are all included in the protection scope of the present invention.

Claims

1. A method for preparing a polypropylene recyclable outdoor fabric, characterized in that The steps include: (1) Design of polypropylene molecular structure for outdoor fabrics and its fabric preparation The designed polypropylene molecular weight distribution index PDI is 2.3-2.5, and the number average molecular weight Mn is 50,000 -100000g / mol, weight average molecular weight Mw is 100000-200000g / mol; melt index MFI is 18g / 10min (230℃, 2.16kg); using solution-dyed polypropylene fiber as raw material, determining the organization structure and weaving process parameters, and preparing polypropylene fabric; (2) Light-resistant and waterproof finishing of polypropylene fabric Firstly, the polypropylene fabric is placed in a light stabilizer for light resistance finishing, and then the polypropylene fabric is waterproofed with a waterproof finishing agent to obtain the finished polypropylene fabric; (3) Design and preparation of polypropylene film The molecular weight distribution index PDI is about 2.2-2.6, the number average molecular weight Mn is 70000-120000 g / mol, the weight average molecular weight Mw is 130000-250000 g / mol, and the melt index MFI is 12 g / 10 min (230° C., 2.16 kg); the polypropylene melt added with a thermoplastic polyurethane additive is first made into a thick film by a biaxial stretching process, and then the thick film is longitudinally stretched and transversely stretched by a stretching machine, the stretching speed is controlled to be 10 mm / s-30 mm / s, the stretching temperature is 150-170° C., and the polypropylene film is obtained after heat setting and cooling, and the polypropylene film is modified; (4) Polypropylene fabric and polypropylene film composite Adhesive is used to compound polypropylene fabric and polypropylene film, wherein the lamination temperature is 150-190°C, the adhesive layer thickness is 5-15 μm, and the lamination pressure is 0.5-1.5 MPa.

2. The method for preparing a polypropylene recyclable outdoor fabric according to claim 1, characterized in that: In the step (1), the fabric structure adopts plain weave, and the fabric process parameters include loom speed, warp and weft density, machine tension and weaving shrinkage, wherein the loom speed is 200-300 rpm, the warp density in the warp and weft density is 60 yarns / cm, and the weft density is 40 yarns / cm, the warp tension in the machine tension is 300-400 g / root, and the weft tension is 200-300 g / root, and the weft shrinkage in the warp direction is 8-10%, and the weft direction is 5-7%.

3. The method for preparing a polypropylene recyclable outdoor fabric according to claim 1, characterized in that: In the step (2), the light stabilizer is selected from one or more of bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, 2-(2H-benzotriazol-2-yl)-4,6-di(1-methyl-1-phenylethyl)phenol or 2-(2'-hydroxy-3',5'-di-tert-pentylphenyl)benzotriazole.

4. The method for preparing a polypropylene recyclable outdoor fabric according to claim 1, characterized in that: In the step (2), the waterproof finishing agent is selected from one or more of polyether-modified siloxane, siloxane polymer or fluorine-free acrylic waterproofing agent.

5. The method for preparing a polypropylene recyclable outdoor fabric according to claim 1, characterized in that: In the step (2), in the light-resistant finishing, the concentration of the light stabilizer is 50 g / L, the finishing temperature is 150° C., the setting time is 5 min, and the pH is 5; in the waterproof finishing, the concentration of the waterproof finishing agent is 20-50 g / L, the finishing temperature is 170° C., and the setting time is 2 min.

6. The method for preparing a polypropylene recyclable outdoor fabric according to claim 1, characterized in that: In the step (3), the polypropylene film is modified by plasma treatment, the treatment power is set to 50-150W, and the treatment time is 30-90s.

7. The method for preparing a polypropylene recyclable outdoor fabric according to claim 1, characterized in that: In the step (3), the adhesive is an environmentally friendly adhesive, such as water-based polyurethane adhesive, water-based acrylic adhesive or EVA hot melt adhesive; the concentration of the adhesive is 10%-20%.

8. The method for preparing a polypropylene recyclable outdoor fabric according to claim 1, characterized in that: In the step (4), an automatic scraping mechanism is used to evenly apply the adhesive to the polypropylene fabric. The automatic scraping mechanism includes a machine platform, a transverse screw module, a lifting screw module and a scraping assembly. The transverse screw module is installed on the transverse frame of the machine platform. The transverse screw module is connected to and drives the lifting screw module to move transversely, thereby driving the scraping assembly to move transversely, so as to evenly apply the adhesive to the polypropylene fabric. The lifting screw module is connected to the scraping assembly through a connecting plate to drive the scraping assembly to move up and down. The scraping assembly includes a mounting plate and a front scraper, a rear scraper and a glue applicator connected to the mounting plate. The front scraper is used to apply the adhesive to the polypropylene fabric. The rear scraper is longer than the front scraper and is used to process the adhesive retained after the front scraper is applied. The glue applicator is used to extrude the adhesive.

9. The method for preparing a polypropylene recyclable outdoor fabric according to claim 8, characterized in that: The glue applicator comprises a storage hopper, a discharging tray and a pusher, the storage hopper is provided with a storage cavity for storing adhesive and conveying it to the discharging tray, the discharging tray is connected to the lower end of the storage hopper, and comprises a pushing section and a discharging head, the pushing section is provided with a pushing cavity, the discharging head is provided with a discharging port, the front section of the pushing cavity is connected to the discharging port, and the rear section of the pushing cavity is connected to the storage cavity; the pusher is used to push the adhesive from the pushing cavity to the discharging port, and comprises a pushing cylinder and a pushing rack, the pushing cylinder is connected and drives the pushing rack to move forward and backward, the pushing rack comprises a front stopper, a rear stopper and a connecting rod, the connecting rod connects the front stopper and the rear stopper, the front stopper and the rear stopper can both block the pushing cavity, the rear stopper is connected with a baffle, and the baffle is used to block the storage cavity; The pushing section is also provided with a cavity for accommodating the rear stopper and the baffle; The gluing step of the gluing device comprises: (1) The pusher is in the initial position, the adhesive at the bottom falls into the rear section of the pusher cavity, and the front stopper blocks the front section of the pusher cavity to prevent the adhesive from flowing into the discharge port; (2) The push cylinder is started, driving the push rack forward, the front stopper moves forward to the top of the front section of the push chamber, the rear stopper moves forward to the position of the front stopper in step (1), the baffle blocks the storage chamber, the discharge port is opened, and the adhesive in the rear section of the push chamber in step (1) is glued through the discharge port; (3) After the gluing is completed, the push cylinder is reset, driving the push rack to retreat and reset to the position of step (1). After the reset, the adhesive at the bottom falls into the rear section of the push cavity; (4) Repeat steps (2) and (3) when applying glue next time.

10. The method for preparing a polypropylene recyclable outdoor fabric according to claim 8, characterized in that: The automatic scraping mechanism also includes a cloth presser, which is used to press the polypropylene fabric; the cloth presser includes a cloth pressing plate and a spring rod, the upper end of the cloth pressing plate is connected to the spring rod, and the spring rod is connected to the cross frame of the machine, and an electromagnet is provided at the corresponding position of the machine, and the electromagnet is used to adsorb the cloth pressing plate to enable the cloth pressing plate to press the fabric, and a rubber pad is provided at the bottom of the cloth pressing plate.

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