An infrared camouflage composite yarn, its preparation method and application

Abstract

This invention discloses an infrared camouflage composite yarn, its preparation method, and its application. The preparation process involves first preparing a preform, then dispersing aluminum powder and tin-doped indium oxide powder on a softened film to form an infrared-resistant film. The infrared-resistant film is then coated onto the preform using a layered structure design to prepare a composite preform. Combined with heat treatment, the yarn is then hot-stretched to obtain the improved infrared camouflage composite yarn. The infrared camouflage composite yarn prepared by this invention not only possesses excellent infrared camouflage capability and durability, but the addition of functional particles does not significantly affect the yarn's mechanical properties, such as breaking strength. The functional particles maintain uniform dispersion, improving the uniformity of infrared camouflage performance. This method is suitable for preparing infrared camouflage products, such as military jackets, tents, and backpacks.

Description

Technical Field

[0001] This invention relates to the field of infrared camouflage, specifically to an infrared camouflage composite yarn, its preparation method, and its application. Background Technology

[0002] Infrared camouflage involves absorbing and attenuating infrared radiation energy through physical or chemical treatments, improving material structure, and applying infrared physics principles. With the rapid development of technology and the deployment of various advanced infrared detection equipment, infrared stealth against various targets has become increasingly difficult, making the development of high-performance infrared camouflage materials extremely important.

[0003] However, current research on infrared camouflage materials, both domestically and internationally, mainly focuses on coating and doping techniques. For example, traditional infrared camouflage clothing typically involves coating textile materials with infrared camouflage paint to create various camouflage garments. However, because the operating environment of infrared camouflage clothing is usually harsh, the paint is easily peeled off, affecting its camouflage effect. Another example is CN113999501B, which discloses a near-infrared camouflage masterbatch and its preparation method, as well as near-infrared camouflage fibers and fabrics. This patent describes mixing functional powder with chemical fiber raw materials and extruding it to produce a near-infrared camouflage masterbatch, which is then blended with the chemical fiber raw materials to produce near-infrared camouflage fibers. However, on the one hand, since functional powder is usually inorganic, its compatibility with organic chemical fiber raw materials is poor, leading to uneven dispersion of the functional powder during the masterbatch production process, resulting in inconsistent camouflage effects throughout the camouflage fibers. On the other hand, directly adding functional powder to chemical fiber raw materials during spinning can negatively impact the mechanical properties of the fibers, reducing the quality of the material. Summary of the Invention

[0004] The purpose of this invention is to overcome one or more shortcomings in the prior art and provide an improved method for preparing infrared camouflage composite yarn. The infrared camouflage composite yarn prepared by this method not only has excellent infrared camouflage capability and infrared camouflage durability, but also the addition of functional particles does not affect the mechanical properties of the yarn, such as breaking strength. The functional particles can always maintain uniform dispersion, thereby improving the uniformity of infrared camouflage performance.

[0005] The present invention also provides an infrared camouflage composite yarn prepared by the above method and its application in the preparation of infrared camouflage products (such as military jackets, tents, backpacks, etc.).

[0006] To achieve the above objectives, the present invention employs the following technical solution:

[0007] A method for preparing an infrared camouflage composite yarn, the method comprising:

[0008] The first chemical fiber raw material is made into a columnar preform;

[0009] A second chemical fiber raw material is made into a film, and aluminum powder and tin-doped indium oxide powder are dispersed on the softened film during the softening process to make an infrared-resistant film.

[0010] The infrared-resistant film is coated on the outer surface of the columnar preform to form a composite preform.

[0011] The composite preform is heat-treated and then hot-stretched in a drawing tower to obtain the infrared camouflage composite yarn.

[0012] According to some specific aspects of the present invention, the first chemical fiber raw material may be the same as or different from the second chemical fiber raw material, and each is independently selected from polyester, nylon or polyolefin resin.

[0013] According to one specific aspect of the present invention, both the first chemical fiber raw material and the second chemical fiber raw material are selected from polyester.

[0014] In some embodiments of the present invention, the columnar preform is obtained by mixing and melting the first chemical fiber raw material and selective additives, and then cooling and molding it in a mold.

[0015] In some embodiments of the present invention, the film is made by hot pressing the second chemical fiber raw material and selective additives.

[0016] In some embodiments of the present invention, the additive may be selected from one or a combination of antioxidants, antistatic agents, and heat stabilizers.

[0017] According to some preferred aspects of the invention, the total feed amount of the aluminum powder and the tin-doped indium oxide powder on the softened film is 0.02-1 g / cm³. 2 Further, it was 0.05-0.5 g / cm³. 2 .

[0018] According to some preferred aspects of the invention, the aluminum powder has a particle size of 15-20 μm.

[0019] According to some preferred aspects of the present invention, the particle size of the tin-doped indium oxide powder is 30-50 nm.

[0020] According to some preferred aspects of the present invention, the mass ratio of the aluminum powder to the tin-doped indium oxide powder is 1:0.1-10, more preferably 1:0.2-5, and even more preferably 1:0.5-2.

[0021] Furthermore, the amount of aluminum powder fed is different from the amount of tin-doped indium oxide powder fed.

[0022] Furthermore, the amount of aluminum powder fed is less than the amount of tin-doped indium oxide powder fed.

[0023] According to some preferred aspects of the present invention, in the composite preform, the number of layers of the infrared-resistant film covering the columnar preform is 1-10, more preferably 1-6, and even more preferably 2-6.

[0024] According to some preferred aspects of the invention, the heat treatment temperature is 50-240°C and is less than or equal to the melting points of the first and second chemical fiber raw materials.

[0025] Furthermore, the temperature of the heat treatment differs from the melting point of the first or second chemical fiber raw material by 0-20°C.

[0026] The present invention also provides another technical solution: an infrared camouflage composite yarn prepared by the above-described method for preparing infrared camouflage composite yarn.

[0027] In some embodiments of the present invention, the diameter of the infrared camouflage composite yarn is 1-2 mm.

[0028] Another technical solution provided by the present invention is the application of the above-mentioned infrared camouflage composite yarn in the preparation of infrared camouflage products.

[0029] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0030] This invention addresses the shortcomings of existing methods for imparting infrared camouflage functionality through coating or direct addition to chemical fiber raw materials via spinning. These shortcomings include coatings that are not durable and easily detached, direct spinning that affects yarn mechanical properties, and insufficient and uneven infrared camouflage capabilities. The invention innovatively provides an improved processing technology. This process first prepares a preform and disperses aluminum powder and tin-doped indium oxide powder on a softened film to create an infrared-resistant film. Then, using a layered structure design, the infrared-resistant film is coated onto the preform to prepare a composite preform. After heat treatment, it is then hot-stretched to obtain an improved infrared camouflage composite yarn. In this process, firstly, the synergistic effect of the layered functional structure gives the prepared composite yarn excellent infrared protection performance. This invention innovatively uses aluminum powder and tin-doped indium oxide powder as composite functional powders. Practice has shown that their combination in the layered structure of this invention significantly improves infrared camouflage capabilities compared to single components. Secondly, based on the layered functional structure of this invention… The invention further heat-treats the layered structure to remove air bubbles or cracks that may occur during preparation, resulting in a tighter and stronger overall structure and improved mechanical properties. Third, the functional structure of the invention exists within the layered structure. When the yarn is prepared by hot stretching, the transfer of functional powders or collapse of the overall structure can be reduced or even avoided, which helps maintain mechanical properties and infrared camouflage capabilities. Fourth, the method of the invention can also reduce the negative impact of adding functional powders (aluminum powder and tin-doped indium oxide powder) on the yarn's mechanical properties, or even have virtually no impact. Fifth, the functional powders are located between the layered structures, reducing the reduction in infrared camouflage capabilities caused by the loss or absence of functional powders due to friction. Sixth, the yarn's thickness and infrared camouflage performance can be further controlled by the hot stretching speed and the number of layers of the infrared-resistant film, greatly improving the yarn's utilization efficiency and added value.

[0031] Furthermore, the process of this invention is simple and controllable, non-toxic and pollution-free, and can be continuously mass-produced, making it suitable for industrial applications. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the cylindrical preform processing device in an embodiment of the present invention;

[0033] Figure 2 This is a schematic diagram of a cylindrical preform in an embodiment of the present invention;

[0034] Figure 3 This is a schematic diagram of the structure of the thin film processing apparatus in an embodiment of the present invention;

[0035] Figure 4 This is a schematic diagram of the thin film in an embodiment of the present invention;

[0036] Figure 5This is a schematic diagram illustrating the process of preparing the composite preform in an embodiment of the present invention;

[0037] Figure 6 This is a schematic diagram of the composite preform prepared in an embodiment of the present invention;

[0038] Figure 7 This is a schematic diagram of the hot stretching process via a wire drawing tower in an embodiment of the present invention;

[0039] Figure 8 This is a schematic diagram of the infrared simulation device in an embodiment of the present invention;

[0040] Figure 9 This is a statistical diagram of the temperature difference between the upper and lower surfaces of the composite yarns obtained in Examples 1-5 and Comparative Examples 1-3 during infrared simulation testing in this invention.

[0041] In the attached diagram, the following are the reference numerals: 1. Feed inlet; 2. Multi-temperature zone controller; 3. Rotary controller; 4. Upper temperature zone of extruder; 5. Middle temperature zone of extruder; 6. Lower temperature zone of extruder; 7. Cylindrical die; 8. Pressure sensor; 9. Cylindrical preform; 10. Screw extruder; 11. Heated aluminum plate; 12. Polyester film; 13. Spring; 14. Jack; 15. Functional powder; 16. Heating platform; 17. Composite preform; 17-1. First composite preform; 17-2. Second composite preform; 17-3. Third composite preform; 18. Upper temperature zone of drawing tower; 19. Middle temperature zone of drawing tower; 20. Lower temperature zone of drawing tower; 21. Infrared camouflage composite yarn; 22. Drawing tower; 23. Infrared lamp; 24. Stand; 25. Infrared camouflage material. Detailed Implementation

[0042] This invention provides a method for preparing infrared camouflage composite yarn, the method comprising:

[0043] The first chemical fiber raw material is made into a columnar preform;

[0044] A second chemical fiber raw material is made into a film, and aluminum powder and tin-doped indium oxide powder are dispersed on the softened film during the softening process to make an infrared-resistant film.

[0045] The infrared-resistant film is coated on the outer surface of the columnar preform to form a composite preform.

[0046] The composite preform is heat-treated and then hot-stretched in a drawing tower to obtain the infrared camouflage composite yarn.

[0047] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0048] See Figures 1 to 7 As shown, the implementation method of the infrared camouflage composite yarn of the present invention includes the following steps:

[0049] (1) Adopt Figure 1 The processing apparatus shown prepares columnar preforms, such as cylindrical preforms. The processing apparatus includes a screw extruder 10, a cylindrical die 7, and a pressure sensor 8. The screw extruder 10 includes a feed inlet 1, a multi-temperature zone controller 2, a rotation controller 3, an upper temperature zone 4, a middle temperature zone 5, and a lower temperature zone 6. The feed inlet 1, the upper temperature zone 4, the middle temperature zone 5, the lower temperature zone 6, and the cylindrical die 7 are connected in sequence. The multi-temperature zone controller 2 is used to control the temperature of the upper temperature zone 4, the middle temperature zone 5, and the lower temperature zone 6 of the extruder, respectively. The rotation controller 3 is used to control the screw speed in the screw extruder 10. The pressure sensor 8 is used to control the pressure in the cylindrical die 7. The density of the preform can be adjusted by controlling the pressure.

[0050] During preparation, the first chemical fiber raw material and the auxiliary agent are mixed in a certain mass ratio (for example, 90-120:1) and added through the feed port 1. Then, the mixture is melted through three temperature zones: the upper temperature zone 4, the middle temperature zone 5, and the lower temperature zone 6 of the extruder, and finally extruded into the cylindrical mold 7. When the pressure in the cylindrical mold 7 is monitored by the pressure sensor 8 and reaches the preset pressure value (for example, 5-30MPa), the feeding is stopped, and the mixture is cooled and shaped to form a cylindrical preform.

[0051] Furthermore, the first chemical fiber raw material is polyester, the temperature of the upper temperature zone 4 of the extruder is 75-85℃, the temperature of the middle temperature zone 5 of the extruder is 250-260℃, and the temperature of the lower temperature zone 6 of the extruder is 160-180℃.

[0052] See the prepared cylindrical preform 9. Figure 2 As shown, in some cases, it can be made into a cylindrical prefabricated part 9 with an inner diameter of 2-4cm and a height of 10-20cm.

[0053] (2) Adopt Figure 3 The processing apparatus shown prepares a thin film. The processing apparatus includes two opposing heated aluminum plates 11, a hydraulic jack 14, and four restoring springs 13. One end of each spring 13 is connected to one of the heated aluminum plates 11, and the other end is connected to the other heated aluminum plate 11. The jack 14 is used to lift the lower heated aluminum plate 11 and make it fit against the upper heated aluminum plate 11. For example, the pressure can be maintained at 5-30 MPa when the two heated aluminum plates are fitted together. The heated aluminum plates can be heated to an ideal temperature (for example, 240-260°C).

[0054] When preparing the film, for example, if polyester granules are chosen as the second chemical fiber raw material, then when preparing the polyester film 12, the polyester granules and additives are placed on the lower heating aluminum plate 11 according to a certain mass ratio (for example, 90-120:1). Then, a hydraulic jack 14 is used to press the two heating aluminum plates 11 together, setting the temperature of the heating aluminum plates to 240-260℃. When the pressure of the jack 14 reaches 5-30 MPa, the temperature and pressure are maintained for a period of time. Under high temperature and high pressure, the polyester granules are hot-pressed into a film shape, obtaining a film as shown in the image. Figure 4 The polyester film 12 shown has the following specifications (length, width, and height to be set as needed);

[0055] (3) Preparation of composite preforms, which adopts Figure 5 The schematic diagram of the processing procedure shows that a polyester film 12 is placed flat on a heating platform 16. After the polyester film softens, functional powder 15 (composed of aluminum powder and tin-doped indium oxide powder, with a mass ratio of aluminum powder to tin-doped indium oxide powder of 1:0.1-10, further to 1:0.2-5, and even further to 1:0.5-2) is uniformly dispersed on the surface of the film to form an infrared-resistant film. The total amount of functional powder 15 on the softened film is 0.02-1 g / cm³. 2 Further, it was 0.05-0.5 g / cm³. 2 ;

[0056] Subsequently, an infrared-resistant film is uniformly coated onto the surface of the cylindrical preform 9 to form a composite preform. Depending on the requirements, a first composite preform 17-1 with one layer of coating can be formed, a second composite preform 17-2 with two layers can be formed, and a third composite preform 17-3 with three layers can be formed, as detailed below. Figure 6 As shown;

[0057] (4) Heat treatment of the composite preform, for example, can be carried out in an oven. The heat treatment temperature can be 180-220℃ and the heating time is 0.5-4h, so as to remove bubbles and cracks that may be generated during the coating process as much as possible.

[0058] Then, the yarn is hot-stretched using a drawing tower to obtain infrared camouflage composite yarn; a schematic diagram of the hot-stretching process using a drawing tower is shown below. Figure 7As shown, the drawing tower 22 includes an upper temperature zone 18, a middle temperature zone 19, and a lower temperature zone 20. The temperature of the upper temperature zone 18 is further controlled at 75-85℃, the temperature of the middle temperature zone 19 is controlled at 250-260℃, and the temperature of the lower temperature zone 20 is controlled at 160-180℃. The composite preform 17 is placed in the drawing tower 22. After heating, the composite preform 17 is drawn. The feeding speed of the composite preform 17 is set to 0.05-3mm / min, and the hot drawing speed is set to 200-500mm / min. The composite preform 17 will soften and neck in the drawing tower 22, and finally be drawn into an infrared camouflage composite yarn of a preset size, such as millimeters.

[0059] In some embodiments, a fiber collection mechanism, a preform lowering mechanism, an air-cooling mechanism, etc., may also be included for yarn preparation and post-processing.

[0060] The above-mentioned solution will be further described below with reference to specific embodiments; it should be understood that these embodiments are used to illustrate the basic principles, main features and advantages of the present invention, and the present invention is not limited to the scope of the following embodiments; the implementation conditions used in the embodiments can be further adjusted according to specific requirements, and the implementation conditions not specified are usually the conditions in conventional experiments.

[0061] Unless otherwise specified in the following examples, all raw materials are commercially available or prepared by conventional methods in the art.

[0062] Aluminum powder was purchased from the China National Research Institute of Metallurgy, with specifications (average particle size 15μm; purity 99.9%); tin-doped indium oxide powder was purchased from Ningbo Jinlei Nanomaterials Technology Co., Ltd., with specifications (average particle size 30nm; purity 99.9%); polyester PET granules were purchased from Huizhou Yitong Plastics Technology Co., Ltd., with grade (12819); and additives were purchased from Shanghai Kunrui Chemical Co., Ltd., with model (PVC KY-66).

[0063] Example 1

[0064] This embodiment provides a method for preparing infrared camouflage composite yarn and the infrared camouflage composite yarn made therefrom, using the above-mentioned... Figures 1 to 7 The processing device and process shown are described below:

[0065] Polyester PET granules and additives are fed into the feed inlet of the screw extruder at a mass ratio of 100:1. The temperatures of the upper, middle, and lower temperature zones of the screw extruder are set to 80℃, 255℃, and 180℃, respectively. After heating for 20 minutes, the polyester PET granules and additives melt. The screw speed is then set to 45 rpm, and the molten polyester is extruded into the cylindrical die. The screw rotation is stopped when the pressure sensor below the die reaches 10 MPa. After the die cools, the cylindrical preform is removed, with a diameter of approximately 3 cm and a height of approximately 15 cm.

[0066] Polyester PET granules and additives are placed on a heated aluminum plate at a mass ratio of 100:1. Then, the jack is adjusted until the two heated aluminum plates are closed, and the temperature of the two plates is set to 250℃. When the jack pressure reaches 10MPa, the hot pressing is maintained for 30 minutes. Under high temperature and pressure, the polyester PET granules will be hot-pressed into a film, which is then shaped into a polyester film with dimensions of 100*150*3mm.

[0067] The polyester film is placed on a heating platform and the temperature is set to 250℃. After the polyester film softens, 10g of aluminum powder and tin-doped indium oxide powder are uniformly dispersed on the polyester film of the above specifications in a mass ratio of 1:1 to prepare an infrared-resistant film. Then, the infrared-resistant film is uniformly coated on the surface of the cylindrical preform and only one layer is coated to prepare a composite preform with one layer.

[0068] The composite preform was placed in a vacuum oven at 200℃ for 4 hours to remove bubbles and cracks. Then, the composite preform was placed in a multi-temperature zone drawing tower, with the upper, middle, and lower zones set to 80℃, 255℃, and 180℃, respectively. After heating for 30 minutes, the preform was drawn, with a feed rate of 1 mm / min and a thermal drawing rate of 360 mm / min for the polyester yarn, thus producing an infrared camouflage composite yarn.

[0069] Example 2

[0070] This embodiment provides a method for preparing infrared camouflage composite yarn and the infrared camouflage composite yarn made therefrom, using the above-mentioned... Figures 1 to 7 The processing device and process shown are described below:

[0071] Polyester PET granules and additives are fed into the feed inlet of the screw extruder at a mass ratio of 100:1. The temperatures of the upper, middle and lower temperature zones are set to 80℃, 255℃ and 180℃ respectively. After heating for 20 minutes, the polyester PET granules and additives melt. The screw speed is set to 45 rpm, and the molten polyester is extruded into the cylindrical die. The screw rotation is stopped when the pressure sensor below the die reaches 10 MPa. After the die cools down, the cylindrical preform is removed.

[0072] Polyester PET granules and additives are placed on a heated aluminum plate at a mass ratio of 100:1. Then, the jack is adjusted until the two heated aluminum plates are closed, and the temperature of the two plates is set to 250℃. When the jack pressure reaches 10MPa, the hot pressing is maintained for 30 minutes. Under high temperature and pressure, the polyester PET granules will be hot-pressed into a film, which is then shaped into a polyester film with dimensions of 100*150*3mm.

[0073] The polyester film is placed on a heating platform and the temperature is set to 250℃. After the polyester film softens, 10g of aluminum powder and tin-doped indium oxide powder are uniformly dispersed on the polyester film of the above specifications in a mass ratio of 2:1 to prepare an infrared-resistant film. Then, the infrared-resistant film is uniformly coated on the surface of the cylindrical preform and only one layer is coated to prepare a composite preform with one layer.

[0074] The composite preform was placed in a vacuum oven at 200℃ for 4 hours to remove bubbles and cracks. Then, the composite preform was placed in a multi-temperature zone drawing tower, with the upper, middle, and lower zones set to 80℃, 255℃, and 180℃, respectively. After heating for 30 minutes, the preform was drawn, with a feed rate of 1 mm / min and a thermal drawing rate of 360 mm / min for the polyester yarn, thus producing an infrared camouflage composite yarn.

[0075] Example 3

[0076] This embodiment provides a method for preparing infrared camouflage composite yarn and the infrared camouflage composite yarn made therefrom, using the above-mentioned... Figures 1 to 7 The processing device and process shown are described below:

[0077] Polyester PET granules and additives are fed into the feed inlet of the screw extruder at a mass ratio of 100:1. The temperatures of the upper, middle and lower temperature zones are set to 80℃, 255℃ and 180℃ respectively. After heating for 20 minutes, the polyester PET granules and additives melt. The screw speed is set to 45 rpm, and the molten polyester is extruded into the cylindrical die. The screw rotation is stopped when the pressure sensor below the die reaches 10 MPa. After the die cools down, the cylindrical preform is removed.

[0078] Polyester PET granules and additives are placed on a heated aluminum plate at a mass ratio of 100:1. Then, the jack is adjusted until the two heated aluminum plates are closed, and the temperature of the two plates is set to 250℃. When the jack pressure reaches 10MPa, the hot pressing is maintained for 30 minutes. Under high temperature and pressure, the polyester PET granules will be hot-pressed into a film, which is then shaped into a polyester film with dimensions of 100*150*3mm.

[0079] The polyester film is placed on a heating platform and the temperature is set to 250℃. After the polyester film softens, 10g of aluminum powder and tin-doped indium oxide powder are evenly dispersed on the polyester film of the above specifications in a mass ratio of 1:2 to prepare an infrared-resistant film. Then, the infrared-resistant film is evenly coated on the surface of the cylindrical preform and only one layer is coated to prepare a composite preform with one layer.

[0080] The composite preform was placed in a vacuum oven at 200℃ for 4 hours to remove bubbles and cracks. Then, the composite preform was placed in a multi-temperature zone drawing tower, with the upper, middle, and lower zones set to 80℃, 255℃, and 180℃, respectively. After heating for 30 minutes, the preform was drawn, with a feed rate of 1 mm / min and a thermal drawing rate of 360 mm / min for the polyester yarn, thus producing an infrared camouflage composite yarn.

[0081] Example 4

[0082] This embodiment provides a method for preparing infrared camouflage composite yarn and the infrared camouflage composite yarn made therefrom, using the above-mentioned... Figures 1 to 7 The processing device and process shown are described below:

[0083] Polyester PET granules and additives are fed into the feed inlet of the screw extruder at a mass ratio of 100:1. The temperatures of the upper, middle and lower temperature zones are set to 80℃, 255℃ and 180℃ respectively. After heating for 20 minutes, the polyester PET granules and additives melt. The screw speed is set to 45 rpm, and the molten polyester is extruded into the cylindrical die. The screw rotation is stopped when the pressure sensor below the die reaches 10 MPa. After the die cools down, the cylindrical preform is removed.

[0084] Polyester PET granules and additives are placed on a heated aluminum plate at a mass ratio of 100:1. Then, the jack is adjusted until the two heated aluminum plates are closed, and the temperature of the two plates is set to 250℃. When the jack pressure reaches 10MPa, the hot pressing is maintained for 30 minutes. Under high temperature and pressure, the polyester PET granules will be hot-pressed into a film, which is then shaped into a polyester film with dimensions of 200*150*3mm.

[0085] The polyester film is placed on a heating platform and the temperature is set to 250℃. After the polyester film softens, 10g of aluminum powder and tin-doped indium oxide powder are evenly dispersed on the polyester film of the above specifications in a mass ratio of 1:2 to prepare an infrared-resistant film. Then, the infrared-resistant film is evenly coated on the surface of the cylindrical preform and coated in two layers to prepare a composite preform with two layers.

[0086] The composite preform was placed in a vacuum oven at 200℃ for 4 hours to remove bubbles and cracks. Then, the composite preform was placed in a multi-temperature zone drawing tower, with the upper, middle, and lower zones set to 80℃, 255℃, and 180℃, respectively. After heating for 30 minutes, the preform was drawn, with a feed rate of 1 mm / min and a thermal drawing rate of 360 mm / min for the polyester yarn, thus producing an infrared camouflage composite yarn.

[0087] Example 5

[0088] This embodiment provides a method for preparing infrared camouflage composite yarn and the infrared camouflage composite yarn made therefrom, using the above-mentioned... Figures 1 to 7 The processing device and process shown are described below:

[0089] Polyester PET granules and additives are fed into the feed inlet of the screw extruder at a mass ratio of 100:1. The temperatures of the upper, middle and lower temperature zones are set to 80℃, 255℃ and 180℃ respectively. After heating for 20 minutes, the polyester PET granules and additives melt. The screw speed is set to 45 rpm, and the molten polyester is extruded into the cylindrical die. The screw rotation is stopped when the pressure sensor below the die reaches 10 MPa. After the die cools down, the cylindrical preform is removed.

[0090] Polyester PET granules and additives are placed on a heated aluminum plate at a mass ratio of 100:1. Then, the jack is adjusted until the two heated aluminum plates are closed, and the temperature of the two plates is set to 250℃. When the jack pressure reaches 10MPa, the hot pressing is maintained for 30 minutes. Under high temperature and pressure, the polyester PET granules will be hot-pressed into a film, which is then shaped into a polyester film with dimensions of 300*150*3mm.

[0091] The polyester film was placed on a heating platform and the temperature was set to 250°C. After the polyester film softened, 10g of aluminum powder and tin-doped indium oxide powder were evenly dispersed on the polyester film of the above specifications in a mass ratio of 1:2 to prepare an infrared-resistant film. Then, the infrared-resistant film was evenly coated on the surface of the cylindrical preform in three layers to prepare a three-layer composite preform.

[0092] The composite preform was placed in a vacuum oven at 200℃ for 4 hours to remove bubbles and cracks. Then, the composite preform was placed in a multi-temperature zone drawing tower, with the upper, middle, and lower zones set to 80℃, 255℃, and 180℃, respectively. After heating for 30 minutes, the preform was drawn, with a feed rate of 1 mm / min and a thermal drawing rate of 360 mm / min for the polyester yarn, thus producing an infrared camouflage composite yarn.

[0093] Comparative Example 1

[0094] The method is basically the same as in Example 1, except that aluminum powder is not added, and only 10g of tin-doped indium oxide powder is dispersed.

[0095] Comparative Example 2

[0096] The method is basically the same as in Example 1, except that: no tin-doped indium oxide powder is added, and only 10g of aluminum powder is dispersed.

[0097] Comparative Example 3

[0098] The basic formula is the same as in Example 1, except that no functional powder is added, that is, neither aluminum powder nor tin-doped indium oxide powder is added.

[0099] Comparative Example 4

[0100] The process is basically the same as in Example 1, except that: no heat treatment is performed, and the composite preform is directly subjected to thermal stretching in a wire drawing tower.

[0101] Performance testing

[0102] (1) The composite yarns prepared in Examples 1-5 and Comparative Examples 1-4 were subjected to strength tests and anti-pilling tests.

[0103] Strength performance test index: GB / T 3916-2013 "Determination of breaking strength and elongation at break of single yarn in packaged textiles".

[0104] Pilling and fuzzing test index: GB / T 21196.2-2007 "Textiles - Martindale Method - Determination of Abrasion Resistance of Fabrics - Part 2: Determination of Specimen Breakage" (Fabric preparation: The spun fibers are woven into the fabric in a mesh pattern; specific parameters are: fabric weight 200 g / m²). 2 The fabric is 1 / 2 twill weave, with a spacing of 0.5mm between adjacent infrared camouflage fibers. The warp composition is 105D48F polyester + 80D infrared camouflage fiber, and the weft composition is 105D48F polyester + 80D infrared camouflage fiber. The manufacturing process is the same as that of twill checkered conductive fabric.

[0105] The test results are shown in Table 1.

[0106] Table 1

[0107]

[0108] The results in Table 1 show that the breaking strength of the infrared camouflage composite yarns prepared in Examples 1-5 is basically equivalent to that of Comparative Examples 1-3, and the anti-pilling performance remains basically unchanged. It can be seen that the addition of functional powder in this invention does not have a significant negative impact on the mechanical properties of the yarn, and overcomes the problem of sacrificing one aspect for another after conventional addition.

[0109] (2) Infrared simulation test indicators: Through self-built infrared simulation device, such as Figure 8 As shown, infrared camouflage material 25 is placed on stand 24. The distance between infrared lamp 23 and infrared camouflage material 25 (preparation process: spun fibers are woven into the fabric in a mesh pattern; specific parameters are: fabric weight 200 g / m², 1 / 2 twill weave, spacing between adjacent infrared camouflage fibers 0.5 mm, warp composition 105D48F polyester + 80D infrared camouflage fiber, weft composition 105D48F polyester + 80D infrared camouflage fiber, process is the same as twill checkered conductive fabric) is controlled at 10 cm. The temperature of the upper and lower surfaces of infrared camouflage material 25 is recorded by an infrared thermometer. This device simulates infrared light emitted by the human body or military weapons. Infrared camouflage material can absorb infrared radiation, creating a temperature difference between the upper and lower surfaces, thereby reducing the radiation intensity of the target, decreasing the probability of being detected by infrared detectors, and increasing security.

[0110] See test results Figure 9 As shown; among them, the upper and lower surfaces of the material without added functional powder have almost no temperature difference (using Comparative Example 3), while the upper and lower surfaces of the material with added functional powder have a significant temperature difference.

[0111] Furthermore, as shown in Examples 1-3, the temperature difference of the anti-counterfeiting material is the largest and the camouflage effect is the best when the ratio of tin-doped indium oxide powder to aluminum powder is 2:1. The temperature difference is the second largest and the camouflage effect is the second largest when the ratio of tin-doped indium oxide powder to aluminum powder is 1:2. The temperature difference is the smallest when the ratio of tin-doped indium oxide powder to aluminum powder is 1:1. However, in general, compared with Comparative Examples 1-3, the temperature difference on the surface of the material is larger and the camouflage effect is better.

[0112] Examples 3-5 show that the infrared camouflage performance increases with the number of layers of the anti-infrared film. In particular, with more layers, the temperature difference increases dramatically within a certain time, resulting in a rapid increase in infrared camouflage capability. This is believed to be due to the layered structure of this invention. When both indium tin oxide (ITO) powder and aluminum powder are used in the layered structure, ITO powder tends to absorb infrared light, while aluminum powder tends to reflect it. Due to the layered structure, especially with the increase in the number of layers, the transmitted infrared light is repeatedly reflected and absorbed between layers. Therefore, when the overall functional powder focuses on absorption and supplements reflection, the layered structure design of this invention contributes more to the temperature difference. (See also...) Figure 9As shown, within a certain time period, such as 20s or 40s, when only one layer is added between Example 5 and Example 4, and between Example 4 and Example 3, the improvement of Example 5 and Example 4 is significantly greater than that of Example 4 and Example 3. This indicates that when the layered coating layer is combined with an overall functional powder that focuses on absorption and is supplemented by reflection, for example, when the amount of tin-doped indium oxide powder added is greater than that of aluminum powder, it can bring about an unexpectedly larger temperature difference, that is, more significant infrared camouflage performance.

[0113] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

[0114] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

Claims

1. A method for preparing an infrared camouflage composite yarn, characterized in that, The preparation method includes: A columnar preform is made by mixing and melting the first chemical fiber raw material and the additives, then cooling and shaping it in a mold. An infrared-resistant film is produced by hot-pressing a second chemical fiber raw material and additives into a film. During the softening process, aluminum powder and tin-doped indium oxide powder are dispersed on the softened film. The mass ratio of aluminum powder to tin-doped indium oxide powder is 1:0.5-2, and the total amount of aluminum powder and tin-doped indium oxide powder on the softened film is 0.02-1 g / cm³. 2 In the columnar preform and the film, the corresponding additives are each independently selected from one or more combinations of antioxidants, antistatic agents, and heat stabilizers. The infrared-resistant film is coated on the outer surface of the columnar preform to form a composite preform. The number of layers of the infrared-resistant film on the columnar preform is 2-10. The composite preform is heat-treated and then hot-stretched in a drawing tower to obtain the infrared camouflage composite yarn; the heat treatment temperature is 50-240℃ and is less than or equal to the melting point of the first chemical fiber raw material and the second chemical fiber raw material.

2. The method for preparing infrared camouflage composite yarn according to claim 1, characterized in that, The first chemical fiber raw material may be the same as or different from the second chemical fiber raw material, and each is independently selected from polyester, nylon or polyolefin resin.

3. The method for preparing infrared camouflage composite yarn according to claim 1, characterized in that, The total amount of aluminum powder and tin-doped indium oxide powder added to the softened film is 0.05-0.5 g / cm³. 2 ; and / or, the aluminum powder has a particle size of 15-20 μm, and the tin-doped indium oxide powder has a particle size of 30-50 nm.

4. The method for preparing infrared camouflage composite yarn according to claim 1, characterized in that, The amount of aluminum powder fed is different from the amount of tin-doped indium oxide powder fed.

5. The method for preparing the infrared camouflage composite yarn according to claim 4, characterized in that, The amount of aluminum powder fed is less than the amount of tin-doped indium oxide powder fed.

6. The method for preparing infrared camouflage composite yarn according to claim 1, characterized in that, In the composite preform, the number of infrared-resistant film coating layers on the columnar preform is 2-6.

7. The method for preparing infrared camouflage composite yarn according to claim 1, characterized in that, The temperature of the heat treatment differs from the melting point of the first or second chemical fiber raw material by 0-20°C.

8. An infrared camouflage composite yarn prepared by the method of any one of claims 1-7.

9. The application of the infrared camouflage composite yarn of claim 8 in the preparation of infrared camouflage products.

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