A moisture-permeable sun-proof laminated composite fabric and a method for manufacturing the same

Abstract

This invention relates to the field of layered composite fabrics, specifically to a breathable and sun-protective layered composite fabric and its preparation method. The fabric comprises two layers: an inner layer and an outer layer. The inner layer is made of a blend of hemp and cotton fibers, exhibiting good breathability. The outer layer is made from polylactic acid (PLA), which has been modified to incorporate toughening components such as nitrile rubber and sun-protective components such as nano-zinc oxide and 2-hydroxy-4-(methacryloyloxy)benzophenone. The addition of the toughening components gives the PLA fabric good tensile properties, while the addition of the sun-protective components provides excellent sun protection, preventing UV damage to the skin and mitigating the yellowing problem inherent in PLA fabrics exposed to sunlight.

Description

Technical Field

[0001] This invention relates to the field of layered composite fabrics, specifically to a moisture-permeable and sun-protective layered composite fabric and its preparation method. Background Technology

[0002] Sunscreen fabrics typically employ a coating of sunscreen components on the fabric surface to reflect or absorb ultraviolet rays, thus achieving sun protection. However, the presence of this coating layer can lead to poor moisture permeability. Furthermore, sunscreen fabrics are often made of chemically synthesized materials, which have poor biodegradability and cause environmental pollution.

[0003] Chinese patent CN117382267B discloses a cooling and breathable fabric for sun protection clothing. The fabric base consists of a two-layer structure: an inner layer and an outer layer. The inner layer is made of a blend of nylon fiber and antibacterial cooling polylactic acid fiber, and the outer layer is made of a blend of polyester fiber and antibacterial cooling polylactic acid fiber. The base fabric is immersed in a protective liquid to obtain the cooling and breathable fabric for sun protection clothing. However, the immersion treatment can easily cause a decrease in the fabric's moisture permeability, and polylactic acid fiber has the problems of high brittleness and poor tensile properties. Summary of the Invention

[0004] This invention addresses the shortcomings of existing technologies by providing a breathable and sun-protective layered composite fabric to solve the problems of poor breathability and insufficient tensile properties in sun-protective fabrics containing polylactic acid fibers.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A method for preparing a moisture-permeable and sun-protective layered composite fabric includes the following steps:

[0007] Step 1: Add nitrile rubber, alkenyl modified nano zinc oxide, and 2-hydroxy-4-(methacryloyloxy)benzophenone to tetrahydrofuran, and mix ultrasonically to obtain a monomer dispersion;

[0008] Add benzoyl peroxide to chloroform and stir to dissolve, thus obtaining an initiator solution;

[0009] Polylactic acid was added to tetrahydrofuran and dissolved to obtain a polylactic acid solution. A monomer dispersion and an initiator solution were added dropwise to the polylactic acid solution. After the addition was complete, the reaction was carried out. After the reaction was completed, the mixture was allowed to settle, filtered, washed, and dried to obtain modified polylactic acid.

[0010] Step 2: Modified polylactic acid is melt-spun to obtain polylactic acid fiber filaments;

[0011] Polylactic acid (PLA) fiber filaments are spun into fabrics through a knitting process to obtain PLA fabrics.

[0012] Step 3: Blend hemp fiber and cotton fiber to obtain blended yarn. Then, use the blended yarn to knit fabric to obtain hemp / cotton blended fabric.

[0013] A breathable and sun-protective layered composite fabric is made by using hemp / cotton blended fabric as the inner layer and polylactic acid fabric as the outer layer, and then laminating the inner and outer layers together with equal areas.

[0014] Preferably, in step one, the mass ratio of polylactic acid solution, monomer dispersion, and initiator solution is (650-850):(630-870):(52-72); the monomer dispersion and initiator solution are added for the same time, 60-90 min, and the reaction is carried out under reflux at 60-70°C for 5-7 h.

[0015] Preferably, in step one, the mass ratio of nitrile rubber, alkenyl modified nano zinc oxide, 2-hydroxy-4-(methacryloyloxy)benzophenone, and tetrahydrofuran in the monomer dispersion is (60-80):(15-20):(55-70):(500-700).

[0016] Preferably, in step one, the mass ratio of benzoyl peroxide to chloroform in the initiator solution is 1:(25-35).

[0017] Preferably, in step one: the mass ratio of polylactic acid to tetrahydrofuran in the polylactic acid solution is 100:(550-750).

[0018] Preferably, the alkenyl-modified nano-zinc oxide in step one is prepared by the following steps:

[0019] Nano zinc oxide was added to an ethanol aqueous solution, ultrasonically dispersed, and the pH was adjusted to 3-4 to obtain a nano zinc oxide dispersion. γ-methacryloxypropyltrimethoxysilane was added to the nano zinc oxide dispersion, and the reaction was carried out. After the reaction was completed, the mixture was filtered, washed, and dried to obtain alkenyl-modified nano zinc oxide.

[0020] Preferably, the mass ratio of the nano zinc oxide, γ-methacryloxypropyltrimethoxysilane, and aqueous ethanol solution is 8:(10-15):(100-120), and the reaction conditions are 8-10 h at 55-65 °C.

[0021] Preferably, in step two, the melt spinning process includes: a spinning temperature of 220-230℃; a winding speed of 350-450m / min; a drawing temperature of 135-145℃ and a drawing ratio of 5 times; and a heat setting temperature of 110-120℃.

[0022] Preferably, in step two: the polylactic acid fiber filament has a single filament fineness of 1.4-1.6D, and the polylactic acid fabric has a basis weight of 100-120g / m². 2 .

[0023] Preferably, in step three: the mass ratio of hemp fiber to cotton fiber is (50-60):(40-50), the yarn count of the blended yarn is 40-50S (English count), and the weight of the hemp / cotton blended fabric is 100-120 g / m². 2 .

[0024] Preferably, the blending process includes: opening cotton fibers and hemp fibers separately, mixing them, and then processing them sequentially through mixing and opening, carding, drawing, roving and spinning processes.

[0025] Preferably, when the cotton fiber and hemp fiber are opened separately or mixed, the opening process is carried out at a speed 5-10% lower than that of conventional cotton fiber opening.

[0026] Preferably, the carding process involves using a wool roller carding machine to card the mixed fibers, wherein the rotation speed of the large cylinder of the wool roller carding machine is 90-100 r / min.

[0027] Preferably, the drawing process is a three-stage drawing process, with 8 strands fed in each stage. The back zone draft ratio of the first drawing stage is 1.6-1.8 times, and the back zone draft ratios of the second and third drawing stages are the same, both being 1.05-1.1 times.

[0028] Preferably, the process parameters for the roving process are: roving tex twist coefficient of 50-55 and spindle speed of 460-480 r / min.

[0029] Preferably, the process parameters for the spinning process are: a spinning tex twist coefficient of 340-360, a sliver output speed of 12-16 m / min, and a spindle speed of 5000-7000 r / min.

[0030] The present invention also discloses a moisture-permeable and sun-protective layered composite fabric prepared by the preparation method of the moisture-permeable and sun-protective layered composite fabric as described above.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0032] The fabric of this invention comprises a two-layer structure: an inner layer and an outer layer. The inner layer is made of a blend of hemp and cotton fibers. Both hemp and cotton fibers have excellent moisture absorption properties, and the cross-section of hemp fibers exhibits a hollow structure with numerous longitudinally connected cracks and pores, giving the hemp fibers a large number of capillary channels that allow moisture to quickly diffuse and transfer to the external environment, achieving good moisture permeability. The outer layer is made of polylactic acid (PLA). As a biodegradable material, PLA, when used in combination with hemp and cotton fibers, gives the fabric good environmental friendliness. Furthermore, PLA, after modification, has good sun protection properties, and as the outer layer of the fabric, it enables the fabric to block ultraviolet rays.

[0033] The modification treatment of polylactic acid (PLA) includes grafting toughening component nitrile rubber and sun protection components nano zinc oxide and 2-hydroxy-4-(methacryloyloxy)benzophenone onto PLA molecules. The introduction of toughening components can effectively overcome the problem of poor tensile properties caused by PLA's high brittleness and low elongation at break. The addition of sun protection components can effectively improve the UV resistance of PLA fibers, thereby improving the sun protection performance of PLA fabrics. This can not only prevent UV damage to human skin, but also improve the problem of yellowing of PLA fabrics due to sunlight.

[0034] Under the action of an initiator, nitrile rubber, alkenyl-modified nano zinc oxide, and 2-hydroxy-4-(methacryloyloxy)benzophenone undergo a graft copolymerization reaction on the polylactic acid molecular chain through the carbon-carbon double bonds contained in their respective molecules. This chemically bonds the toughening and sun protection components to the polylactic acid molecules, avoiding the reduction in toughening and sun protection effects caused by poor dispersion compatibility or migration of small organic molecules. In addition, nano zinc oxide, as an inorganic filler, can also enhance toughness and further improve the tensile properties of polylactic acid fabrics.

[0035] Both the inner and outer fabrics are spun using a knitting process, resulting in good elasticity and high wearing comfort. Furthermore, the knitted fabric is formed by perforated loops, making it highly breathable. Attached Figure Description

[0036] Figure 1 This is a flowchart illustrating the preparation process of the moisture-permeable and sun-protective layered composite fabric in this invention.

[0037] Figure 2 The bar chart shows the test results of the moisture permeability of the moisture-permeable and sun-protective layered composite fabrics prepared in Examples 1-5 and Comparative Examples 1-2 of the present invention.

[0038] Figure 3 The bar chart shows the sun protection performance test results of the moisture-permeable and sun-protective layered composite fabrics prepared in Examples 1-5 and Comparative Examples 1-2 of the present invention.

[0039] Figure 4 The bar graph shows the tensile properties of polylactic acid fiber filaments prepared in Examples 1-5 and Comparative Examples 1-2 of the present invention. Detailed Implementation

[0040] Example 1

[0041] This embodiment discloses a method for preparing a moisture-permeable and sun-protective layered composite fabric, including the following steps:

[0042] Step 1: Add nitrile rubber, alkenyl-modified nano zinc oxide, and 2-hydroxy-4-(methacryloyloxy)benzophenone to tetrahydrofuran. The mass ratio of nitrile rubber, alkenyl-modified nano zinc oxide, 2-hydroxy-4-(methacryloyloxy)benzophenone, and tetrahydrofuran is 60:15:55:500. After ultrasonic mixing at 50kHz for 30min, a monomer dispersion is obtained.

[0043] Benzoyl peroxide was added to chloroform at a mass ratio of 1:25 and stirred at 150 r / min until dissolved to obtain an initiator solution.

[0044] Polylactic acid was added to tetrahydrofuran at a mass ratio of 100:550. The mixture was stirred at 60°C and 150 r / min until dissolved to obtain a polylactic acid solution.

[0045] Monomer dispersion and initiator solution were added dropwise to a polylactic acid solution. The mass ratio of polylactic acid solution, monomer dispersion, and initiator solution was 650:630:52. The dropwise addition time for the monomer dispersion and initiator solution was the same, 60 min. After the addition was completed, the mixture was refluxed at 60 °C for 7 h. After the reaction was completed, a reaction mixture was obtained. Three times the mass of the reaction mixture was added to the reaction mixture to precipitate the reaction product. The precipitate was filtered and washed three times with deionized water and then three times with ethanol. The precipitate was then dried in a drying oven at 50 °C for 15 h to obtain modified polylactic acid.

[0046] The alkenyl-modified nano zinc oxide is prepared by the following steps:

[0047] Nano zinc oxide was added to a 95wt% ethanol aqueous solution and ultrasonically mixed at 50kHz for 30min. Then, 1mol / L hydrochloric acid aqueous solution was added to adjust the pH to 3 to obtain a nano zinc oxide dispersion. γ-methacryloxypropyltrimethoxysilane was added to the nano zinc oxide dispersion. The mass ratio of nano zinc oxide, γ-methacryloxypropyltrimethoxysilane, and 95wt% ethanol aqueous solution was 8:10:100. The reaction was carried out at 55℃ for 10h. After the reaction was completed, the mixture was filtered. The residue was washed three times with deionized water and dried in a 50℃ drying oven for 12h to obtain alkenyl-modified nano zinc oxide.

[0048] Step 2: Modified polylactic acid is melt-spun to obtain polylactic acid fiber filaments. The fineness of the polylactic acid fiber filaments is 1.5D.

[0049] The melt spinning process includes: spinning temperature of 220℃; winding speed of 350m / min; drawing temperature of 135℃; drawing ratio of 5 times; and heat setting temperature of 110℃.

[0050] Polylactic acid (PLA) fiber filaments are spun into fabric using a knitting process to obtain PLA fabric. The PLA fabric has a weight of 100 g / m². 2 ;

[0051] Step 3: Blend hemp fiber and cotton fiber in a 50:50 mass ratio to obtain a blended yarn with a yarn count of 40S. Then, knit the blended yarn into a fabric to obtain a hemp / cotton blended fabric with a weight of 100g / m². 2 ;

[0052] The blending process includes: opening hemp fiber and cotton fiber separately, mixing them, and then processing them in sequence through the processes of blending and opening, carding, drawing, roving and spinning.

[0053] In the process of opening cotton and hemp fibers separately and in combination, the opening speed is 5% lower than that of conventional cotton fiber opening. The carding process uses a wool roller carding machine to card the mixed fibers. The speed of the large cylinder of the wool roller carding machine is 90 r / min. The drawing process uses a three-stage drawing process, with 8 strands fed in each stage. The back zone draft ratio of the first drawing is 1.6 times, and the back zone draft ratios of the second and third drawing are the same, both at 1.1 times. The process parameters for the roving process are: roving tex twist coefficient of 50 and spindle speed of 480 r / min. The process parameters for the spinning process are: spinning tex twist coefficient of 340, sliver exit speed of 12 m / min and spindle speed of 5000 r / min.

[0054] A breathable and sun-protective layered composite fabric is made by using hemp / cotton blended fabric as the inner layer and polylactic acid fabric as the outer layer, and using all-cotton sewing thread to laminate the inner and outer layers together in equal areas.

[0055] Example 2

[0056] This embodiment discloses a method for preparing a moisture-permeable and sun-protective layered composite fabric, including the following steps:

[0057] Step 1: Add nitrile rubber, alkenyl-modified nano zinc oxide, and 2-hydroxy-4-(methacryloyloxy)benzophenone to tetrahydrofuran. The mass ratio of nitrile rubber, alkenyl-modified nano zinc oxide, 2-hydroxy-4-(methacryloyloxy)benzophenone, and tetrahydrofuran is 80:20:70:700. After ultrasonic mixing at 50kHz for 30 minutes, a monomer dispersion is obtained.

[0058] Benzoyl peroxide was added to chloroform at a mass ratio of 1:35 and stirred at 150 r / min until dissolved to obtain an initiator solution.

[0059] Polylactic acid was added to tetrahydrofuran at a mass ratio of 100:750. The mixture was stirred at 60°C and 150 r / min until dissolved to obtain a polylactic acid solution.

[0060] Monomer dispersion and initiator solution were added dropwise to a polylactic acid solution. The mass ratio of polylactic acid solution, monomer dispersion, and initiator solution was 850:870:72. The addition time for monomer dispersion and initiator solution was the same, 90 min. After the addition was completed, the mixture was refluxed at 70℃ for 5 h. After the reaction was completed, a reaction mixture was obtained. Three times the mass of deionized water was added to the reaction mixture to precipitate the reaction product. The precipitate was filtered and washed three times with deionized water and then three times with ethanol. The precipitate was then dried in a drying oven at 50℃ for 15 h to obtain modified polylactic acid.

[0061] The alkenyl-modified nano zinc oxide is prepared by the following steps:

[0062] Nano zinc oxide was added to a 95wt% ethanol aqueous solution and ultrasonically mixed at 50kHz for 30min. Then, 1mol / L hydrochloric acid aqueous solution was added to adjust the pH to 4 to obtain a nano zinc oxide dispersion. γ-methacryloyloxypropyltrimethoxysilane was added to the nano zinc oxide dispersion. The mass ratio of nano zinc oxide, γ-methacryloyloxypropyltrimethoxysilane, and 95wt% ethanol aqueous solution was 8:15:120. The reaction was carried out at 65℃ for 8h. After the reaction was completed, the mixture was filtered. The residue was washed three times with deionized water and dried in a 50℃ drying oven for 12h to obtain alkenyl-modified nano zinc oxide.

[0063] Step 2: Modified polylactic acid is melt-spun to obtain polylactic acid fiber filaments. The fineness of the polylactic acid fiber filaments is 1.5D.

[0064] The melt spinning process includes: spinning temperature of 230℃; winding speed of 450m / min; drawing temperature of 145℃; drawing ratio of 5 times; and heat setting temperature of 120℃.

[0065] Polylactic acid (PLA) fiber filaments are spun into fabric using a knitting process to obtain PLA fabric with a weight of 120 g / m². 2 ;

[0066] Step 3: Blend hemp fiber and cotton fiber at a mass ratio of 60:40 to obtain a blended yarn with a yarn count of 50S. Then, knit the blended yarn into a fabric to obtain a hemp / cotton blended fabric with a weight of 120 g / m². 2 ;

[0067] The blending process includes: opening hemp fiber and cotton fiber separately, mixing them, and then processing them in sequence through the processes of blending and opening, carding, drawing, roving and spinning.

[0068] In the process of opening cotton and hemp fibers separately and in combination, the opening speed is 10% lower than that of conventional cotton fiber opening. The carding process uses a wool roller carding machine to card the mixed fibers. The speed of the large cylinder of the wool roller carding machine is 100 r / min. The drawing process uses a three-stage drawing process, with 8 strands fed in each stage. The back zone draft ratio of the first drawing is 1.8 times, and the back zone draft ratios of the second and third drawing are the same, both at 1.05 times. The process parameters for the roving process are: roving tex twist coefficient of 55 and spindle speed of 460 r / min. The process parameters for the spinning process are: spinning tex twist coefficient of 360, sliver output speed of 16 m / min and spindle speed of 7000 r / min.

[0069] A breathable and sun-protective layered composite fabric is made by using hemp / cotton blended fabric as the inner layer and polylactic acid fabric as the outer layer, and using all-cotton sewing thread to laminate the inner and outer layers together in equal areas.

[0070] Example 3

[0071] This embodiment discloses a method for preparing a moisture-permeable and sun-protective layered composite fabric, including the following steps:

[0072] Step 1: Add nitrile rubber, alkenyl-modified nano zinc oxide, and 2-hydroxy-4-(methacryloyloxy)benzophenone to tetrahydrofuran. The mass ratio of nitrile rubber, alkenyl-modified nano zinc oxide, 2-hydroxy-4-(methacryloyloxy)benzophenone, and tetrahydrofuran is 65:16:58:550. After ultrasonic mixing at 50kHz for 30min, a monomer dispersion is obtained.

[0073] Benzoyl peroxide was added to chloroform at a mass ratio of 1:30 and stirred at 150 r / min until dissolved to obtain an initiator solution.

[0074] Polylactic acid was added to tetrahydrofuran at a mass ratio of 100:600. The mixture was stirred at 60°C and 150 r / min until dissolved to obtain a polylactic acid solution.

[0075] Monomer dispersion and initiator solution were added dropwise to a polylactic acid solution. The mass ratio of polylactic acid solution, monomer dispersion, and initiator solution was 700:680:58. The dropwise addition time for the monomer dispersion and initiator solution was the same, 70 min. After the dropwise addition was completed, the mixture was refluxed at 65℃ for 6 h. After the reaction was completed, a reaction mixture was obtained. Three times the mass of the reaction mixture was added to the reaction mixture to precipitate the reaction product. The precipitate was filtered and washed three times with deionized water and then three times with ethanol. The precipitate was then dried in a drying oven at 50℃ for 15 h to obtain modified polylactic acid.

[0076] The alkenyl-modified nano zinc oxide is prepared by the following steps:

[0077] Nano zinc oxide was added to a 95wt% ethanol aqueous solution and ultrasonically mixed at 50kHz for 30min. Then, 1mol / L hydrochloric acid aqueous solution was added to adjust the pH to 3.5 to obtain a nano zinc oxide dispersion. γ-methacryloxypropyltrimethoxysilane was added to the nano zinc oxide dispersion. The mass ratio of nano zinc oxide, γ-methacryloxypropyltrimethoxysilane, and 95wt% ethanol aqueous solution was 8:11:105. The reaction was carried out at 60℃ for 9h. After the reaction was completed, the mixture was filtered. The residue was washed three times with deionized water and dried in a 50℃ drying oven for 12h to obtain alkenyl-modified nano zinc oxide.

[0078] Step 2: Modified polylactic acid is melt-spun to obtain polylactic acid fiber filaments. The fineness of the polylactic acid fiber filaments is 1.5D.

[0079] The melt spinning process includes: spinning temperature of 225℃; winding speed of 400m / min; drawing temperature of 140℃; drawing ratio of 5; and heat setting temperature of 115℃.

[0080] Polylactic acid (PLA) fiber filaments are spun into fabric using a knitting process to obtain PLA fabric. The PLA fabric has a weight of 110 g / m². 2 ;

[0081] Step 3: Blend hemp fiber and cotton fiber at a mass ratio of 55:45 to obtain a blended yarn with a yarn count of 45S. Then, knit the blended yarn into a fabric to obtain a hemp / cotton blended fabric with a weight of 110 g / m². 2 ;

[0082] The blending process includes: opening hemp fiber and cotton fiber separately, mixing them, and then processing them in sequence through the processes of blending and opening, carding, drawing, roving and spinning.

[0083] In the process of opening cotton and hemp fibers separately and in combination, the opening speed is 7% lower than that of conventional cotton fiber opening. The carding process uses a wool roller carding machine to card the mixed fibers. The speed of the large cylinder of the wool roller carding machine is 95 r / min. The drawing process uses a three-stage drawing process, with 8 strands fed in each stage. The back zone draft ratio of the first drawing is 1.7 times, and the back zone draft ratios of the second and third drawing are the same, both at 1.08 times. The process parameters for the roving process are: roving tex twist coefficient of 55 and spindle speed of 470 r / min. The process parameters for the spinning process are: spinning tex twist coefficient of 350, sliver exit speed of 14 m / min and spindle speed of 6000 r / min.

[0084] A breathable and sun-protective layered composite fabric is made by using hemp / cotton blended fabric as the inner layer and polylactic acid fabric as the outer layer, and using all-cotton sewing thread to laminate the inner and outer layers together in equal areas.

[0085] Example 4

[0086] This embodiment discloses a method for preparing a moisture-permeable and sun-protective layered composite fabric, including the following steps:

[0087] Step 1: Add nitrile rubber, alkenyl-modified nano zinc oxide, and 2-hydroxy-4-(methacryloyloxy)benzophenone to tetrahydrofuran. The mass ratio of nitrile rubber, alkenyl-modified nano zinc oxide, 2-hydroxy-4-(methacryloyloxy)benzophenone, and tetrahydrofuran is 70:17.5:62:600. After ultrasonic mixing at 50kHz for 30 minutes, a monomer dispersion is obtained.

[0088] Benzoyl peroxide was added to chloroform at a mass ratio of 1:30 and stirred at 150 r / min until dissolved to obtain an initiator solution.

[0089] Polylactic acid was added to tetrahydrofuran at a mass ratio of 100:650. The mixture was stirred at 60°C and 150 r / min until dissolved to obtain a polylactic acid solution.

[0090] Monomer dispersion and initiator solution were added dropwise to a polylactic acid solution. The mass ratio of polylactic acid solution, monomer dispersion, and initiator solution was 750:750:64. The dropwise addition time for the monomer dispersion and initiator solution was the same, 75 min. After the dropwise addition was completed, the mixture was refluxed at 65℃ for 6 h. After the reaction was completed, a reaction mixture was obtained. Three times the mass of the reaction mixture was added to the reaction mixture to precipitate the reaction product. The precipitate was filtered and washed three times with deionized water and then three times with ethanol. The precipitate was then dried in a drying oven at 50℃ for 15 h to obtain modified polylactic acid.

[0091] The alkenyl-modified nano zinc oxide is prepared by the following steps:

[0092] Nano zinc oxide was added to a 95wt% ethanol aqueous solution and ultrasonically mixed at 50kHz for 30min. Then, 1mol / L hydrochloric acid aqueous solution was added to adjust the pH to 3.5 to obtain a nano zinc oxide dispersion. γ-methacryloxypropyltrimethoxysilane was added to the nano zinc oxide dispersion. The mass ratio of nano zinc oxide, γ-methacryloxypropyltrimethoxysilane, and 95wt% ethanol aqueous solution was 8:12.5:110. The reaction was carried out at 60℃ for 9h. After the reaction was completed, the mixture was filtered. The residue was washed three times with deionized water and dried in a 50℃ drying oven for 12h to obtain alkenyl-modified nano zinc oxide.

[0093] Step 2: Modified polylactic acid is melt-spun to obtain polylactic acid fiber filaments. The fineness of the polylactic acid fiber filaments is 1.5D.

[0094] The melt spinning process includes: spinning temperature of 225℃; winding speed of 400m / min; drawing temperature of 140℃; drawing ratio of 5; and heat setting temperature of 115℃.

[0095] Polylactic acid (PLA) fiber filaments are spun into fabric using a knitting process to obtain PLA fabric. The PLA fabric has a weight of 110 g / m². 2 ;

[0096] Step 3: Blend hemp fiber and cotton fiber at a mass ratio of 55:45 to obtain a blended yarn with a yarn count of 45S. Then, knit the blended yarn into a fabric to obtain a hemp / cotton blended fabric with a weight of 110 g / m². 2 ;

[0097] The blending process includes: opening hemp fiber and cotton fiber separately, mixing them, and then processing them in sequence through the processes of blending and opening, carding, drawing, roving and spinning.

[0098] In the process of opening cotton and hemp fibers separately and in combination, the opening speed is 7.5% lower than that of conventional cotton fiber opening. The carding process uses a wool roller carding machine to card the mixed fibers. The speed of the large cylinder of the wool roller carding machine is 95 r / min. The drawing process uses a three-stage drawing process, with 8 strands fed in each stage. The back zone draft ratio of the first drawing is 1.7 times, and the back zone draft ratios of the second and third drawing are the same, both at 1.08 times. The process parameters for the roving process are: roving tex twist coefficient of 55 and spindle speed of 470 r / min. The process parameters for the spinning process are: spinning tex twist coefficient of 350, sliver exit speed of 14 m / min and spindle speed of 6000 r / min.

[0099] A breathable and sun-protective layered composite fabric is made by using hemp / cotton blended fabric as the inner layer and polylactic acid fabric as the outer layer, and using all-cotton sewing thread to laminate the inner and outer layers together in equal areas.

[0100] Example 5

[0101] This embodiment discloses a method for preparing a moisture-permeable and sun-protective layered composite fabric, including the following steps:

[0102] Step 1: Add nitrile rubber, alkenyl-modified nano zinc oxide, and 2-hydroxy-4-(methacryloyloxy)benzophenone to tetrahydrofuran. The mass ratio of nitrile rubber, alkenyl-modified nano zinc oxide, 2-hydroxy-4-(methacryloyloxy)benzophenone, and tetrahydrofuran is 75:19:66:650. After ultrasonic mixing at 50kHz for 30min, a monomer dispersion is obtained.

[0103] Benzoyl peroxide was added to chloroform at a mass ratio of 1:30 and stirred at 150 r / min until dissolved to obtain an initiator solution.

[0104] Polylactic acid was added to tetrahydrofuran at a mass ratio of 100:700. The mixture was stirred at 60°C and 150 r / min until dissolved to obtain a polylactic acid solution.

[0105] Monomer dispersion and initiator solution were added dropwise to a polylactic acid solution. The mass ratio of polylactic acid solution, monomer dispersion, and initiator solution was 850:810:68. The dropwise addition time for the monomer dispersion and initiator solution was the same, 80 min. After the dropwise addition was completed, the mixture was refluxed at 65℃ for 6 h. After the reaction was completed, a reaction mixture was obtained. Three times the mass of deionized water was added to the reaction mixture to precipitate the reaction product. The precipitate was filtered and washed three times with deionized water and then three times with ethanol. The precipitate was then dried in a drying oven at 50℃ for 15 h to obtain modified polylactic acid.

[0106] The alkenyl-modified nano zinc oxide is prepared by the following steps:

[0107] Nano zinc oxide was added to a 95wt% ethanol aqueous solution and ultrasonically mixed at 50kHz for 30 min. Then, 1mol / L hydrochloric acid aqueous solution was added to adjust the pH to 3.5 to obtain a nano zinc oxide dispersion. γ-methacryloxypropyltrimethoxysilane was added to the nano zinc oxide dispersion. The mass ratio of nano zinc oxide, γ-methacryloxypropyltrimethoxysilane, and 95wt% ethanol aqueous solution was 8:14:115. The reaction was carried out at 60℃ for 9 h. After the reaction was completed, the mixture was filtered. The residue was washed three times with deionized water and dried in a 50℃ drying oven for 12 h to obtain alkenyl-modified nano zinc oxide.

[0108] Step 2: Modified polylactic acid is melt-spun to obtain polylactic acid fiber filaments. The fineness of the polylactic acid fiber filaments is 1.5D.

[0109] The melt spinning process includes: spinning temperature of 225℃; winding speed of 400m / min; drawing temperature of 140℃; drawing ratio of 5; and heat setting temperature of 115℃.

[0110] Polylactic acid (PLA) fiber filaments are spun into fabric using a knitting process to obtain PLA fabric. The PLA fabric has a weight of 110 g / m². 2 ;

[0111] Step 3: Blend hemp fiber and cotton fiber at a mass ratio of 55:45 to obtain a blended yarn with a yarn count of 45S. Then, knit the blended yarn into a fabric to obtain a hemp / cotton blended fabric with a weight of 110 g / m². 2 ;

[0112] The blending process includes: opening hemp fiber and cotton fiber separately, mixing them, and then processing them in sequence through the processes of blending and opening, carding, drawing, roving and spinning.

[0113] In the process of opening cotton and hemp fibers separately and in combination, the opening speed is 7.5% lower than that of conventional cotton fiber opening. The carding process uses a wool roller carding machine to card the mixed fibers. The speed of the large cylinder of the wool roller carding machine is 95 r / min. The drawing process uses a three-stage drawing process, with 8 strands fed in each stage. The back zone draft ratio of the first drawing is 1.7 times, and the back zone draft ratios of the second and third drawing are the same, both at 1.08 times. The process parameters for the roving process are: roving tex twist coefficient of 55 and spindle speed of 470 r / min. The process parameters for the spinning process are: spinning tex twist coefficient of 350, sliver exit speed of 14 m / min and spindle speed of 6000 r / min.

[0114] A breathable and sun-protective layered composite fabric is made by using hemp / cotton blended fabric as the inner layer and polylactic acid fabric as the outer layer, and using all-cotton sewing thread to laminate the inner and outer layers together in equal areas.

[0115] Comparative Example 1

[0116] This comparative example discloses a method for preparing a moisture-permeable and sun-protective layered composite fabric, comprising the following steps:

[0117] Step 1: Add nitrile rubber, nano zinc oxide, and 2-hydroxy-4-(methacryloyloxy)benzophenone to tetrahydrofuran. The mass ratio of nitrile rubber, nano zinc oxide, 2-hydroxy-4-(methacryloyloxy)benzophenone, and tetrahydrofuran is 80:20:70:700. After ultrasonic mixing at 50kHz for 30 minutes, a monomer dispersion is obtained.

[0118] Benzoyl peroxide was added to chloroform at a mass ratio of 1:35 and stirred at 150 r / min until dissolved to obtain an initiator solution.

[0119] Polylactic acid was added to tetrahydrofuran at a mass ratio of 100:750. The mixture was stirred at 60°C and 150 r / min until dissolved to obtain a polylactic acid solution.

[0120] Monomer dispersion and initiator solution were added dropwise to a polylactic acid solution. The mass ratio of polylactic acid solution, monomer dispersion, and initiator solution was 850:870:72. The addition time for monomer dispersion and initiator solution was the same, 90 min. After the addition was completed, the mixture was refluxed at 70℃ for 5 h. After the reaction was completed, a reaction mixture was obtained. Three times the mass of deionized water was added to the reaction mixture to precipitate the reaction product. The precipitate was filtered and washed three times with deionized water and then three times with ethanol. The precipitate was then dried in a drying oven at 50℃ for 15 h to obtain modified polylactic acid.

[0121] Step 2: Modified polylactic acid is melt-spun to obtain polylactic acid fiber filaments. The fineness of the polylactic acid fiber filaments is 1.5D.

[0122] The melt spinning process includes: spinning temperature of 230℃; winding speed of 450m / min; drawing temperature of 145℃; drawing ratio of 5 times; and heat setting temperature of 120℃.

[0123] Polylactic acid (PLA) fiber filaments are spun into fabric using a knitting process to obtain PLA fabric with a weight of 120 g / m². 2 ;

[0124] Step 3: Blend hemp fiber and cotton fiber at a mass ratio of 60:40 to obtain a blended yarn with a yarn count of 50S. Then, knit the blended yarn into a fabric to obtain a hemp / cotton blended fabric with a weight of 120 g / m². 2 ;

[0125] The blending process includes: opening hemp fiber and cotton fiber separately, mixing them, and then processing them in sequence through the processes of blending and opening, carding, drawing, roving and spinning.

[0126] In the process of opening cotton and hemp fibers separately and in combination, the opening speed is 10% lower than that of conventional cotton fiber opening. The carding process uses a wool roller carding machine to card the mixed fibers. The speed of the large cylinder of the wool roller carding machine is 100 r / min. The drawing process uses a three-stage drawing process, with 8 strands fed in each stage. The back zone draft ratio of the first drawing is 1.8 times, and the back zone draft ratios of the second and third drawing are the same, both at 1.05 times. The process parameters for the roving process are: roving tex twist coefficient of 55 and spindle speed of 460 r / min. The process parameters for the spinning process are: spinning tex twist coefficient of 360, sliver output speed of 16 m / min and spindle speed of 7000 r / min.

[0127] A breathable and sun-protective layered composite fabric is made by using hemp / cotton blended fabric as the inner layer and polylactic acid fabric as the outer layer, and using all-cotton sewing thread to laminate the inner and outer layers together in equal areas.

[0128] Comparative Example 2

[0129] This comparative example discloses a method for preparing a moisture-permeable and sun-protective layered composite fabric, comprising the following steps:

[0130] Step 1: Add nitrile rubber and 2-hydroxy-4-(methacryloyloxy)benzophenone to tetrahydrofuran. The mass ratio of nitrile rubber, 2-hydroxy-4-(methacryloyloxy)benzophenone and tetrahydrofuran is 80:0:720. After ultrasonic mixing at 50kHz for 30min, a monomer dispersion is obtained.

[0131] Benzoyl peroxide was added to chloroform at a mass ratio of 1:35 and stirred at 150 r / min until dissolved to obtain an initiator solution.

[0132] Polylactic acid was added to tetrahydrofuran at a mass ratio of 100:750. The mixture was stirred at 60°C and 150 r / min until dissolved to obtain a polylactic acid solution.

[0133] Monomer dispersion and initiator solution were added dropwise to a polylactic acid solution. The mass ratio of polylactic acid solution, monomer dispersion, and initiator solution was 850:870:72. The addition time for monomer dispersion and initiator solution was the same, 90 min. After the addition was completed, the mixture was refluxed at 70℃ for 5 h. After the reaction was completed, a reaction mixture was obtained. Three times the mass of deionized water was added to the reaction mixture to precipitate the reaction product. The precipitate was filtered and washed three times with deionized water and then three times with ethanol. The precipitate was then dried in a drying oven at 50℃ for 15 h to obtain modified polylactic acid.

[0134] Step 2: Modified polylactic acid is melt-spun to obtain polylactic acid fiber filaments. The fineness of the polylactic acid fiber filaments is 1.5D.

[0135] The melt spinning process includes: spinning temperature of 230℃; winding speed of 450m / min; drawing temperature of 145℃; drawing ratio of 5 times; and heat setting temperature of 120℃.

[0136] Polylactic acid (PLA) fiber filaments are spun into fabric using a knitting process to obtain PLA fabric with a weight of 120 g / m². 2 ;

[0137] Step 3: Blend hemp fiber and cotton fiber at a mass ratio of 60:40 to obtain a blended yarn with a yarn count of 50S. Then, knit the blended yarn into a fabric to obtain a hemp / cotton blended fabric with a weight of 120 g / m². 2 ;

[0138] The blending process includes: opening hemp fiber and cotton fiber separately, mixing them, and then processing them in sequence through the processes of blending and opening, carding, drawing, roving and spinning.

[0139] In the process of opening cotton and hemp fibers separately and in combination, the opening speed is 10% lower than that of conventional cotton fiber opening. The carding process uses a wool roller carding machine to card the mixed fibers. The speed of the large cylinder of the wool roller carding machine is 100 r / min. The drawing process uses a three-stage drawing process, with 8 strands fed in each stage. The back zone draft ratio of the first drawing is 1.8 times, and the back zone draft ratios of the second and third drawing are the same, both at 1.05 times. The process parameters for the roving process are: roving tex twist coefficient of 55 and spindle speed of 460 r / min. The process parameters for the spinning process are: spinning tex twist coefficient of 360, sliver output speed of 16 m / min and spindle speed of 7000 r / min.

[0140] A breathable and sun-protective layered composite fabric is made by using hemp / cotton blended fabric as the inner layer and polylactic acid fabric as the outer layer, and using all-cotton sewing thread to laminate the inner and outer layers together in equal areas.

[0141] In the above embodiments and comparative examples, the nitrile rubber was liquid nitrile rubber, purchased from Dongguan Chengjie Plastic Raw Materials Co., Ltd., model: RB302, molecular weight: 10,000-20,000; the polylactic acid was purchased from Anhui Fengyuan Futailai Polylactic Acid Co., Ltd., grade: FY601, density: 1.24 g / m³. 3 Melting point: 170℃, melt index (190℃ / 2.16kg): 9; Nano zinc oxide was purchased from Shijiazhuang Guanchi Chemical Technology Co., Ltd., particle size: 30-50nm; Hemp fiber was purchased from Jingde County Jinwei Hemp Industry Co., Ltd., fiber strength ≥235, fiber length ≥130mm, cut short before use to make the length between 35-40mm; Cotton fiber is long-staple cotton from Xinjiang with a length of 38-39.7mm; All-cotton sewing thread was purchased from Taizhou Yidu Garment Co., Ltd., product specification: 40S / 2.

[0142] Test case

[0143] The performance of the moisture-permeable and sun-protective layered composite fabrics prepared in the above embodiments and comparative examples was tested:

[0144] (1) Moisture permeability test: The moisture permeability of the inner fabrics prepared in Examples 1-5 and Comparative Examples 1-2 was determined according to the standard GB / T12704.1-2009 "Textiles - Test Methods for Moisture Permeability of Fabrics - Part 1: Moisture Absorption Method". The results are shown in Table 1.

[0145]

[0146] As shown in Table 1, the moisture-permeable and sun-protective layered composite fabric prepared by this invention has excellent moisture permeability. Both hemp and cotton fibers have excellent moisture absorption properties, and the cross-section of hemp fibers exhibits a hollow structure with numerous longitudinally connected cracks and pores, giving them a large number of capillary channels that allow for rapid moisture diffusion and transfer, thus achieving good moisture permeability. The preparation process of the inner layer fabrics in Comparative Examples 1 and 2 is the same as in Example 2, and their moisture permeability is similar.

[0147] (2) Sun protection performance test: The UPF (ultraviolet protection factor) of the outer fabrics prepared in Examples 1-5 and Comparative Examples 1-2 was determined according to the standard GB / T18830-2009 "Evaluation of UV protection performance of textiles". The test results are shown in Table 2.

[0148]

[0149] As shown in Table 2, the breathable and sun-protective layered composite fabric prepared by this invention has good sun protection performance. During the modification of polylactic acid (PLA), the introduction of sun protection components nano-zinc oxide and 2-hydroxy-4-(methacryloyloxy)benzophenone effectively improves sun protection performance. Under the action of an initiator, alkenyl-modified nano-zinc oxide and 2-hydroxy-4-(methacryloyloxy)benzophenone undergo graft copolymerization on the PLA molecular chain through their respective carbon-carbon double bonds, chemically bonding the sun protection components to the PLA molecules. This avoids the reduced toughening and sun protection effect caused by poor dispersion compatibility between inorganic sun protection components and PLA, and the migration of organic sun protection components. Compared with Example 2, in Comparative Example 1, the inorganic sun protection component was nano-zinc oxide, which was not linked to the PLA molecules through alkenyl groups, resulting in reduced dispersion compatibility in PLA and a decrease in sun protection performance. In Comparative Example 2, no inorganic sun protection components were added, further reducing sun protection performance.

[0150] (3) Tensile property test: The tensile properties of polylactic acid fiber filaments prepared in Examples 1-5 and Comparative Examples 1-2 were determined according to the standard GB / T14344-2022 "Tension Test Method for Chemical Fiber Filaments". The test results are shown in Table 3.

[0151]

[0152] As shown in Table 3, the breathable and sun-protective layered composite fabric prepared by this invention has good tensile properties. The introduction of the toughening component, nitrile rubber, can effectively improve the elongation at break of polylactic acid (PLA) fiber filaments. Simultaneously, the addition of nano-zinc oxide can enhance the tensile strength of PLA fiber filaments. Compared with Example 2, in Comparative Example 1, the nano-zinc oxide was not linked to the PLA molecules via alkenyl groups, resulting in reduced dispersion compatibility in PLA. While it had no significant effect on the elongation at break, the tensile strength decreased. In Comparative Example 2, no nano-zinc oxide was added, further reducing the tensile strength.

[0153] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for producing a solar protection layered composite fabric which is permeable to moisture, characterized in that Includes the following steps: Step 1: Add nitrile rubber, alkenyl modified nano zinc oxide, and 2-hydroxy-4-(methacryloyloxy)benzophenone to tetrahydrofuran, and mix ultrasonically to obtain a monomer dispersion; Add benzoyl peroxide to chloroform and stir to dissolve, thus obtaining an initiator solution; Polylactic acid was added to tetrahydrofuran and dissolved to obtain a polylactic acid solution. A monomer dispersion and an initiator solution were added dropwise to the polylactic acid solution. After the addition was complete, the reaction was carried out. After the reaction was completed, the mixture was allowed to settle, filtered, washed, and dried to obtain modified polylactic acid. Step 2: Modified polylactic acid is melt-spun to obtain polylactic acid fiber filaments; Polylactic acid (PLA) fiber filaments are spun into fabrics through a knitting process to obtain PLA fabrics. Step 3: Blend hemp fiber and cotton fiber to obtain blended yarn. Then, use the blended yarn to knit fabric to obtain hemp / cotton blended fabric. A breathable and sun-protective layered composite fabric is made by using hemp / cotton blended fabric as the inner layer and polylactic acid fabric as the outer layer, and then laminating the inner and outer layers together with equal areas.

2. The method for preparing a moisture-permeable and sun-protective layered composite fabric according to claim 1, characterized in that, In step one: the mass ratio of polylactic acid solution, monomer dispersion, and initiator solution is (650-850):(630-870):(52-72); the dropping time of monomer dispersion and initiator solution is the same, 60-90 min; the reaction conditions are reflux reaction at 60-70℃ for 5-7 h.

3. The method for preparing a moisture-permeable and sun-protective layered composite fabric according to claim 1, characterized in that, In step one: in the monomer dispersion, the mass ratio of nitrile rubber, alkenyl modified nano zinc oxide, 2-hydroxy-4-(methacryloyloxy)benzophenone, and tetrahydrofuran is (60-80):(15-20):(55-70):(500-700); in the initiator solution, the mass ratio of benzoyl peroxide to chloroform is 1:(25-35); in the polylactic acid solution, the mass ratio of polylactic acid to tetrahydrofuran is 100:(550-750).

4. The method for preparing a moisture-permeable and sun-protective layered composite fabric according to claim 1, characterized in that, The alkenyl-modified nano zinc oxide in step one is prepared by the following steps: Nano zinc oxide was added to an ethanol aqueous solution, ultrasonically dispersed, and the pH was adjusted to 3-4 to obtain a nano zinc oxide dispersion. γ-methacryloxypropyltrimethoxysilane was added to the nano zinc oxide dispersion, and the reaction was carried out. After the reaction was completed, the mixture was filtered, washed, and dried to obtain alkenyl-modified nano zinc oxide.

5. The method for preparing a moisture-permeable and sun-protective layered composite fabric according to claim 4, characterized in that, The mass ratio of the nano zinc oxide, γ-methacryloxypropyltrimethoxysilane, and aqueous ethanol solution is 8:(10-15):(100-120), and the reaction conditions are 8-10 h at 55-65 °C.

6. The method for preparing a moisture-permeable and sun-protective layered composite fabric according to claim 1, characterized in that, In step two, the melt spinning process includes: spinning temperature of 220-230℃; winding speed of 350-450m / min; drawing temperature of 135-145℃; drawing ratio of 5 times; and heat setting temperature of 110-120℃.

7. The method for preparing a moisture-permeable and sun-protective layered composite fabric according to claim 1, characterized in that, In the second step, the single filament fineness of the polylactic acid fiber filament is 1.4-1.6D, and the grammage of the polylactic acid fabric is 100-120g / m 2 .

8. The method for preparing a moisture-permeable and sun-protective layered composite fabric according to claim 1, characterized in that, In step three: the mass ratio of hemp fiber to cotton fiber is (50-60):(40-50), the yarn count of the blended yarn is 40-50S, and the weight of the hemp / cotton blended fabric is 100-120g / m². 2 ; The blending process includes: opening hemp fiber and cotton fiber separately, mixing them, and then processing them in sequence through the processes of blending and opening, carding, drawing, roving and spinning.

9. The method for preparing a moisture-permeable and sun-protective layered composite fabric according to claim 8, characterized in that, The carding process involves using a wool roller carding machine to card the mixed fibers, with the large cylinder of the wool roller carding machine rotating at a speed of 90-100 r / min. The drawing process is a three-stage drawing process, with 8 strands fed in each stage. The back zone draw ratio of the first drawing stage is 1.6-1.8 times, and the back zone draw ratios of the second and third drawing stages are the same, both being 1.05-1.1 times. The process parameters for the roving process are: roving tex twist coefficient of 50-55, spindle speed of 460-480 r / min; The process parameters for the fine spinning process are as follows: fine spinning tex twist coefficient is 340-360, sliver output speed is 12-16m / min, and spindle speed is 5000-7000r / min.

10. A moisture-permeable and sun-protective layered composite fabric prepared by the method of preparing the moisture-permeable and sun-protective layered composite fabric as described in any one of claims 1-9.

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