A preparation method of degradable polypropylene spunbond non-woven fabric

Abstract

The present invention discloses a preparation method of a degradable polypropylene spunbond nonwoven fabric, belonging to the technical field of nonwoven fabrics. The preparation method includes: preparing an oxidation degradation masterbatch, preparing a soft masterbatch, preparing the s-layer spinning, preparing the m-layer spinning, hot rolling and slitting; for preparing the soft masterbatch, a acetone solution of maleic anhydride, polylactic acid, diisopropylbenzene peroxide, styrene and sodium methacrylate are added to a high-speed mixer and mixed evenly, then the acetone is completely volatilized, and then added to a twin-screw extruder for the first melt extrusion. After the first melt extrusion is completed, a mixture is obtained; the mixture and erucamide are added to the twin-screw extruder for the second melt extrusion. After the second melt extrusion is completed, a soft masterbatch is obtained; the present invention can achieve the biodegradation of polypropylene spunbond nonwoven fabrics, and while improving the softness of polypropylene spunbond nonwoven fabrics, improve the strength, ultraviolet resistance and high-temperature resistance of polypropylene spunbond nonwoven fabrics.

Description

Technical Field

[0001] The present invention belongs to the technical field of non-woven fabrics, and particularly relates to a preparation method of degradable polypropylene spunbond non-woven fabrics. Background Art

[0002] Non-woven fabric is a kind of non-woven cloth, which has the characteristics of good anti-tensile deformation, breaking strength and elongation rate, and is widely used in medical protection, personal hygiene care, industrial fabrics, agriculture and other fields. Traditional non-woven fabrics are made by stretching, laminating and bonding fibers in a certain direction, and its disadvantages are poor strength, durability, water resistance and low softness.

[0003] In order to solve the above problems, the most commonly used method at present is to use polypropylene spunbond non-woven fabric instead of traditional non-woven fabric. Polypropylene spunbond non-woven fabric has high strength and water resistance, but polypropylene is difficult to degrade under natural conditions, which causes great harm to the environment, and the softness of polypropylene spunbond non-woven fabric is poor, resulting in limited application fields of polypropylene spunbond non-woven fabric.

[0004] In order to solve the above problems, the most commonly used method at present is to add oxidation degradation masterbatch and soft masterbatch to polypropylene spunbond non-woven fabric, so as to achieve biodegradability of polypropylene spunbond non-woven fabric and improve the softness of polypropylene spunbond non-woven fabric at the same time. However, the addition of oxidation degradation masterbatch and soft masterbatch will affect the strength of polypropylene spunbond non-woven fabric, and also affect the ultraviolet resistance and high temperature resistance of polypropylene. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the present invention provides a preparation method of degradable polypropylene spunbond non-woven fabric, which can achieve biodegradability of polypropylene spunbond non-woven fabric, improve the softness of polypropylene spunbond non-woven fabric, and at the same time improve the strength, ultraviolet resistance and high temperature resistance of polypropylene spunbond non-woven fabric.

[0006] To solve the above technical problems, the following technical solutions are adopted:

[0007] A preparation method of degradable polypropylene spunbond non-woven fabric includes: preparing oxidation degradation masterbatch, preparing soft masterbatch, preparing s-layer spinning, preparing m-layer spinning, hot rolling and slitting;

[0008] To prepare the oxidation-degradable masterbatch, bamboo fibers and ramie fibers are respectively crushed to 300-500 mesh, and then mixed evenly according to a weight ratio of 8-10:1 to obtain mixed fibers; the mixed fibers, N,N'-methylenebisacrylamide, acrylic acid, and water are mixed, and then stirred at a stirring speed of 100-120 rpm at 35-40 °C for 30-35 min. Tannic acid and sodium alginate are added and stirred for 20-25 min. The temperature is raised to 50-55 °C and stirring continues for 20-25 min. Then the stirring speed is increased to 200-220 rpm, and an aqueous ammonium persulfate solution is added dropwise while stirring. The dropping speed of the aqueous ammonium persulfate solution is controlled at 25-30 g / min. After the dropping is completed, stirring continues for 5-10 min, and then it is left to stand at 60-65 °C for 1-1.5 h and then freeze-dried. The temperature during freeze-drying is controlled at -40 °C to -30 °C, and the time is 8-9 h. After freeze-drying, a hydrogel powder is obtained; the hydrogel powder, zinc chloride, anatase titanium dioxide, and dopamine hydrochloride are mixed and then ball-milled. The ball-to-material ratio during ball-milling is controlled at 8-10:1, the rotation speed is 300-320 rpm, and the time is 20-25 min. After ball-milling, a modified hydrogel powder is obtained; polylactic acid, the modified hydrogel powder, and chitosan are added to a twin-screw extruder for melt extrusion. The processing temperature of the twin-screw extruder is controlled at 180-195 °C. After melt extrusion, pelletizing is carried out to obtain the oxidation-degradable masterbatch;

[0009] In the preparation of the oxidation-degradable masterbatch, the mass fraction of ammonium persulfate in the aqueous ammonium persulfate solution is 8-10%;

[0010] The weight-average molecular weight of the polylactic acid is 50,000-100,000;

[0011] The weight ratio of the mixed fibers, N,N'-methylenebisacrylamide, acrylic acid, water, tannic acid, sodium alginate, and the aqueous ammonium persulfate solution is 1000-1100:0.6-0.7:300-320:1100-1200:30-32:20-22:2-2.5;

[0012] The weight ratio of the hydrogel powder, zinc chloride, anatase titanium dioxide, and dopamine hydrochloride is 100-110:10-13:6-8:2-3;

[0013] The weight ratio of the polylactic acid, the modified hydrogel powder, and chitosan is 70-80:20-30:4-7;

[0014] To prepare the soft masterbatch, an acetone solution of maleic anhydride, polylactic acid, diisopropylbenzene peroxide, styrene, and sodium methacrylate are added to a high-speed mixer and mixed evenly. Then, the acetone is completely volatilized at 60-65°C, and the mixture is added to a twin-screw extruder for the first melt extrusion. The processing temperature of the twin-screw extruder is controlled at 190-220°C, and a mixture is obtained after the first melt extrusion. The mixture and erucamide are added to the twin-screw extruder for the second melt extrusion. The processing temperature of the twin-screw extruder is controlled at 195-225°C, and the soft masterbatch is obtained after the second melt extrusion.

[0015] In the preparation of the soft masterbatch, the weight-average molecular weight of the polylactic acid is 50,000-100,000.

[0016] In the acetone solution of maleic anhydride, the weight ratio of maleic anhydride to acetone is 1:1.5-2.

[0017] The weight ratio of the acetone solution of maleic anhydride, polylactic acid, diisopropylbenzene peroxide, styrene, sodium methacrylate, and erucamide is 70-75:4000-4200:3-5:4-5:20-24:30-35.

[0018] To prepare the s-layer spinning, polypropylene, high-melt-index polypropylene, PE-PP block copolymer, oxidation degradation masterbatch, soft masterbatch, and white masterbatch are added to a high-speed mixer in a weight ratio of 75-80:5-8:18-20:8-10:1-1.5:1.5-2.5 and mixed evenly. Then, the mixture is added to a twin-screw extruder for melt extrusion. The processing temperature of the twin-screw extruder is controlled at 190-240°C. After melt extrusion, melt metering, die spinning, and stretching treatments are carried out to obtain the s-layer spinning.

[0019] In the preparation of the s-layer spinning, the MFR of the polypropylene at 230°C and 2.16 kg is 32-40 g / 10 min.

[0020] The MFR of the high-melt-index polypropylene at 230°C and 2.16 kg is 800-1500 g / 10 min.

[0021] The MFR of the PE-PP block copolymer at 230°C and 2.16 kg is 32-40 g / 10 min.

[0022] The white masterbatch, by weight, includes: 80-90 parts of polyethylene, 30-40 parts of titanium dioxide, and 5-8 parts of maleic anhydride grafted polypropylene wax.

[0023] The MFR of the polyethylene at 230°C and 2.16 kg is 1-2 g / 10 min.

[0024] For the preparation of the m-layer spun fiber, high melt index polypropylene and an oxidation degradation masterbatch are added to a high-speed mixer in a weight ratio of 90-95:5-10 and mixed evenly, and then added to a twin-screw extruder for melt extrusion. The processing temperature of the twin-screw extruder is controlled at 230-260 °C. After melt extrusion, melt metering, die head spinning, and stretching treatments are carried out to obtain the m-layer spun fiber;

[0025] In the preparation of the m-layer spun fiber, the MFR of the high melt index polypropylene at 230 °C and 2.16 kg is 800-1500 g / 10 min;

[0026] For the hot rolling and slitting, the s-layer spun fiber and the m-layer spun fiber are separated and laid into a web. From top to bottom, they are the s-layer, s-layer, m-layer, m-layer, s-layer. After the web laying is completed, hot rolling treatment and humidification treatment are carried out simultaneously. The temperature of the patterned roller in the hot rolling treatment is controlled at 140-155 °C, the temperature of the smooth roller is 135-150 °C, the speed of the mesh belt is 450-600 m / min, and the hot rolling pressure is 70-100 daN / cm; after the hot rolling and humidification treatments are completed, drying, winding, and slitting are carried out to obtain the degradable polypropylene spunbond nonwoven fabric.

[0027] The present invention adopts the above technical solutions. Compared with the prior art, it has the following advantages:

[0028] (1) In the preparation method of the degradable polypropylene spunbond nonwoven fabric of the present invention, by making bamboo fiber and ramie fiber into aerogel powder when preparing the oxidation degradation masterbatch, the biodegradation speed of the prepared degradable polypropylene spunbond nonwoven fabric can be improved. After the degradable polypropylene spunbond nonwoven fabric prepared by the present invention is buried in the soil with a surface depth of 15 cm for 5 months, the weight loss rate is 35.5-36.9%;

[0029] (2) In the preparation method of the degradable polypropylene spunbond nonwoven fabric of the present invention, by making bamboo fiber and ramie fiber into aerogel powder when preparing the oxidation degradation masterbatch, the strength of the prepared degradable polypropylene spunbond nonwoven fabric can be improved. The MD strength of the degradable polypropylene spunbond nonwoven fabric prepared by the present invention is 29.4-30.3 N / 5 cm, the CD strength is 15.1-16.5 N / 5 cm, the MD elongation is 70.1-71.6%, and the CD elongation is 85.8-86.7%;

[0030] (3) In the preparation method of the degradable polypropylene spunbond nonwoven fabric of the present invention, by graft-modifying polylactic acid when preparing the soft masterbatch, the softness of the prepared degradable polypropylene spunbond nonwoven fabric can be improved. The MD softness of the degradable polypropylene spunbond nonwoven fabric prepared by the present invention is 3.3-3.5 g, and the CD softness is 1.7-1.9 g;

[0031] (4)The preparation method of the degradable polypropylene spunbond nonwoven fabric of the present invention can improve the ultraviolet resistance of the prepared degradable polypropylene spunbond nonwoven fabric by making bamboo fiber and ramie fiber into aerogel powder when preparing the oxidation degradation masterbatch and graft-modifying polylactic acid when preparing the soft masterbatch. After the degradable polypropylene spunbond nonwoven fabric prepared by the present invention is continuously irradiated under a xenon lamp for 10 days, the MD strength is 29.2 - 30.1 N / 5 cm, the CD strength is 15.0 - 16.2 N / 5 cm, the MD elongation is 69.8 - 71.3%, and the CD elongation is 85.1 - 86.1%.

[0032] (5)The preparation method of the degradable polypropylene spunbond nonwoven fabric of the present invention can improve the high-temperature resistance of the prepared degradable polypropylene spunbond nonwoven fabric by making bamboo fiber and ramie fiber into aerogel powder when preparing the oxidation degradation masterbatch and graft-modifying polylactic acid when preparing the soft masterbatch. After the degradable polypropylene spunbond nonwoven fabric prepared by the present invention is heat-treated at 50 °C for 10 days, the MD strength is 29.1 - 29.8 N / 5 cm, the CD strength is 15.0 - 16.1 N / 5 cm, the MD elongation is 69.4 - 70.9%, and the CD elongation is 84.8 - 86.1%. Detailed Embodiments

[0033] In order to have a clearer understanding of the technical features, objectives, and effects of the present invention, the detailed embodiments of the present invention are now described.

[0034] Example 1

[0035] A preparation method of a degradable polypropylene spunbond nonwoven fabric is specifically as follows:

[0036] 1. Preparation of oxidation-degradable masterbatch: Crush bamboo fiber and ramie fiber to 300 mesh respectively, and mix them evenly according to the weight ratio of 8:1 to obtain mixed fiber; After mixing the mixed fiber, N,N'-methylenebisacrylamide, acrylic acid, and water, stir at a stirring speed of 100 rpm at 35°C for 30 min, add tannic acid and sodium alginate, stir for 20 min, raise the temperature to 50°C, continue stirring for 20 min, then increase the stirring speed to 200 rpm, and dropwise add ammonium persulfate aqueous solution while stirring, control the dropping speed of ammonium persulfate aqueous solution to 25 g / min, continue stirring for 5 min after the dropping is completed, then place it at 60°C and let it stand for 1 h and then perform freeze-drying, control the temperature during freeze-drying to -40°C and the time to 8 h, and obtain hydrogel powder after freeze-drying; Mix the hydrogel powder, zinc chloride, anatase titanium dioxide, and dopamine hydrochloride and then perform ball milling, control the ball-to-material ratio during ball milling to 8-10:1, the rotation speed to 300 rpm, and the time to 20 min, and obtain modified hydrogel powder after ball milling; Add polylactic acid, modified hydrogel powder, and chitosan into a twin-screw extruder for melt extrusion, control the processing temperature of the twin-screw extruder to 180°C, and perform pelletizing after melt extrusion to obtain oxidation-degradable masterbatch;

[0037] The mass fraction of ammonium persulfate in the ammonium persulfate aqueous solution is 8%;

[0038] The weight-average molecular weight of the polylactic acid is 50,000;

[0039] Among them, the weight ratio of the mixed fiber, N,N'-methylenebisacrylamide, acrylic acid, water, tannic acid, sodium alginate, and ammonium persulfate aqueous solution is 1000:0.6:300:1100:30:20:2;

[0040] The weight ratio of the hydrogel powder, zinc chloride, anatase titanium dioxide, and dopamine hydrochloride is 100:10:6:2;

[0041] The weight ratio of the polylactic acid, modified hydrogel powder, and chitosan is 70:20:4;

[0042] 2. Preparation of soft masterbatch: Add the acetone solution of maleic anhydride, polylactic acid, diisopropylbenzene peroxide, styrene, and sodium methacrylate into a high-speed mixer and mix evenly, then place it at 60°C to completely volatilize the acetone, and then add it into a twin-screw extruder for the first melt extrusion, control the processing temperature of the twin-screw extruder to 190°C, and obtain a mixture after the first melt extrusion; Add the mixture and erucamide into a twin-screw extruder for the second melt extrusion, control the processing temperature of the twin-screw extruder to 205°C, and obtain a soft masterbatch after the second melt extrusion;

[0043] The weight-average molecular weight of the polylactic acid is 50,000;

[0044] In the acetone solution of maleic anhydride, the weight ratio of maleic anhydride to acetone is 1:1.5;

[0045] Among them, the weight ratio of the acetone solution of maleic anhydride, polylactic acid, dicumyl peroxide, styrene, sodium methacrylate, and erucamide is 70:4000:3:4:20:30;

[0046] 3. Preparation of s-layer spinning: Polypropylene, high melt flow rate polypropylene, PE-PP block copolymer, oxidation degradation masterbatch, soft masterbatch, and white masterbatch are added to a high-speed mixer in a weight ratio of 75:5:18:8:1:1.5 and mixed evenly, and then added to a twin-screw extruder for melt extrusion. The processing temperature of the twin-screw extruder is controlled at 220 °C. After melt extrusion, melt metering, die spinning, and drawing treatments are carried out to obtain s-layer spinning;

[0047] The MFR of the polypropylene at 230 °C and 2.16 kg is 32 g / 10 min;

[0048] The MFR of the high melt flow rate polypropylene at 230 °C and 2.16 kg is 800 g / 10 min;

[0049] The MFR of the PE-PP block copolymer at 230 °C and 2.16 kg is 32 g / 10 min;

[0050] The white masterbatch, by weight, includes: 80 parts of polyethylene, 30 parts of titanium dioxide, and 5 parts of maleic anhydride grafted polypropylene wax;

[0051] The MFR of the polyethylene at 230 °C and 2.16 kg is 1 g / 10 min;

[0052] 4. Preparation of m-layer spinning: High melt flow rate polypropylene and oxidation degradation masterbatch are added to a high-speed mixer in a weight ratio of 90:5 and mixed evenly, and then added to a twin-screw extruder for melt extrusion. The processing temperature of the twin-screw extruder is controlled at 250 °C. After melt extrusion, melt metering, die spinning, and drawing treatments are carried out to obtain m-layer spinning;

[0053] The MFR of the high melt flow rate polypropylene at 230 °C and 2.16 kg is 800 g / 10 min;

[0054] 5. Hot rolling and slitting: The s-layer spun fibers and m-layer spun fibers are separated and laid into a web. From top to bottom, they are s-layer, s-layer, m-layer, m-layer, s-layer. After the web laying is completed, hot rolling treatment and humidification treatment are carried out simultaneously. Control the temperature of the patterned roll in the hot rolling treatment to be 150 °C, the temperature of the smooth roll to be 140 °C, the speed of the mesh belt to be 580 m / min, and the hot rolling pressure to be 80 daN / cm; after the hot rolling and humidification treatments are completed, drying, winding, and slitting are carried out to obtain the degradable polypropylene spunbond nonwoven fabric.

[0055] Example 2

[0056] A preparation method of a degradable polypropylene spunbond nonwoven fabric is specifically as follows:

[0057] 1. Preparation of the oxidation degradation masterbatch: The bamboo fibers and ramie fibers are respectively crushed to 400 meshes, and then mixed evenly according to a weight ratio of 9:1 to obtain mixed fibers; the mixed fibers, N,N'-methylenebisacrylamide, acrylic acid, and water are mixed, and then stirred at a stirring speed of 110 rpm at 38 °C for 32 min. Tannic acid and sodium alginate are added and stirred for 22 min. The temperature is raised to 52 °C and stirring is continued for 22 min. Then the stirring speed is increased to 210 rpm, and an aqueous ammonium persulfate solution is added dropwise while stirring. Control the dropping speed of the aqueous ammonium persulfate solution to be 28 g / min. After the dropping is completed, stirring is continued for 8 min, and then it is left to stand at 62 °C for 1.2 h and then freeze-dried. Control the temperature during freeze-drying to be -35 °C and the time to be 8.5 h. After the freeze-drying is completed, a hydrogel powder is obtained; the hydrogel powder, zinc chloride, anatase titanium dioxide, and dopamine hydrochloride are mixed and then ball-milled. Control the ball-to-material ratio during ball-milling to be 9:1, the rotation speed to be 310 rpm, and the time to be 22 min. After the ball-milling is completed, a modified hydrogel powder is obtained; polylactic acid, the modified hydrogel powder, and chitosan are added to a twin-screw extruder for melt extrusion. Control the processing temperature of the twin-screw extruder to be 185 °C. After the melt extrusion is completed, pelletizing is carried out to obtain the oxidation degradation masterbatch;

[0058] The mass fraction of ammonium persulfate in the aqueous ammonium persulfate solution is 9%;

[0059] The weight-average molecular weight of the polylactic acid is 80,000;

[0060] Among them, the weight ratio of the mixed fibers, N,N'-methylenebisacrylamide, acrylic acid, water, tannic acid, sodium alginate, and the aqueous ammonium persulfate solution is 1050:0.6:310:1150:31:21:2.2;

[0061] The weight ratio of the hydrogel powder, zinc chloride, anatase titanium dioxide, and dopamine hydrochloride is 105:12:7:2.5;

[0062] The weight ratio of polylactic acid, the modified hydrogel powder, and chitosan is 75:25:5;

[0063] 2. Preparation of soft masterbatch: Add the acetone solution of maleic anhydride, polylactic acid, dicumyl peroxide, styrene, and sodium methacrylate into a high-speed mixer and mix evenly. Then, place it at 62°C to completely volatilize the acetone. After that, add it into a twin-screw extruder for the first melt extrusion, controlling the processing temperature of the twin-screw extruder at 185°C. After the first melt extrusion, a mixture is obtained. Add the mixture and erucamide into the twin-screw extruder for the second melt extrusion, controlling the processing temperature of the twin-screw extruder at 190°C. After the second melt extrusion, a soft masterbatch is obtained;

[0064] The weight-average molecular weight of the polylactic acid is 80,000;

[0065] In the acetone solution of maleic anhydride, the weight ratio of maleic anhydride to acetone is 1:1.8;

[0066] Among them, the weight ratio of the acetone solution of maleic anhydride, polylactic acid, dicumyl peroxide, styrene, sodium methacrylate, and erucamide is 72:4100:4:4.5:22:32;

[0067] 3. Preparation of s-layer spinning: Add polypropylene, high melt index polypropylene, PE-PP block copolymer, oxidation degradation masterbatch, soft masterbatch, and white masterbatch into a high-speed mixer according to a weight ratio of 78:7:19:9:1.2:2 and mix evenly. Then, add it into a twin-screw extruder for melt extrusion, controlling the processing temperature of the twin-screw extruder at 220°C. After melt extrusion, melt metering, die spinning, and drawing treatments are carried out to obtain s-layer spinning;

[0068] The MFR of the polypropylene at 230°C and 2.16 kg is 35 g / 10 min;

[0069] The MFR of the high melt index polypropylene at 230°C and 2.16 kg is 1000 g / 10 min;

[0070] The MFR of the PE-PP block copolymer at 230°C and 2.16 kg is 35 g / 10 min;

[0071] The white masterbatch, by weight, includes: 85 parts of polyethylene, 35 parts of titanium dioxide, and 6 parts of maleic anhydride grafted polypropylene wax;

[0072] The MFR of the polyethylene at 230°C and 2.16 kg is 1.5 g / 10 min;

[0073] 4. Preparation of m-layer spun yarn: High melt index polypropylene and an oxidation degradation masterbatch are added to a high-speed mixer in a weight ratio of 92:8 and mixed evenly, then added to a twin-screw extruder for melt extrusion. Control the processing temperature of the twin-screw extruder at 230 °C. After melt extrusion, perform melt metering, die spinning, and drawing treatments to obtain m-layer spun yarn;

[0074] The MFR of the high melt index polypropylene at 250 °C and 2.16 kg is 1000 g / 10 min;

[0075] 5. Hot rolling and slitting: Separate and lay the s-layer spun yarn and m-layer spun yarn. From top to bottom, they are s-layer, s-layer, m-layer, m-layer, s-layer. After laying the web, perform hot rolling treatment and humidification treatment simultaneously. Control the temperature of the patterned roll in the hot rolling treatment at 152 °C, the temperature of the smooth roll at 142 °C, the speed of the mesh belt at 585 m / min, and the hot rolling pressure at 85 daN / cm; After the hot rolling and humidification treatments, perform drying, winding, and slitting to obtain the degradable polypropylene spunbond nonwoven fabric.

[0076] Example 3

[0077] A preparation method of a degradable polypropylene spunbond nonwoven fabric, specifically:

[0078] 1. Preparation of oxidation degradation masterbatch: Crush bamboo fiber and ramie fiber to 500 meshes respectively, and then mix them evenly in a weight ratio of 10:1 to obtain mixed fibers; After mixing the mixed fibers, N,N'-methylenebisacrylamide, acrylic acid, and water, stir at a stirring speed of 120 rpm at 40 °C for 35 min, add tannic acid and sodium alginate, stir for 25 min, raise the temperature to 55 °C, continue to stir for 25 min, then increase the stirring speed to 220 rpm, and dropwise add an ammonium persulfate aqueous solution while stirring. Control the dropping speed of the ammonium persulfate aqueous solution at 30 g / min. After the dropping is completed, continue to stir for 10 min, then place it at 65 °C and let it stand for 1.5 h, and then perform freeze-drying. Control the temperature during freeze-drying at -30 °C and the time at 9 h. After freeze-drying, obtain hydrogel powder; After mixing the hydrogel powder, zinc chloride, anatase titanium dioxide, and dopamine hydrochloride, perform ball milling. Control the ball-to-material ratio during ball milling at 10:1, the rotation speed at 320 rpm, and the time at 25 min. After ball milling, obtain modified hydrogel powder; Add polylactic acid, modified hydrogel powder, and chitosan to a twin-screw extruder for melt extrusion. Control the processing temperature of the twin-screw extruder at 195 °C. After melt extrusion, perform pelletizing to obtain the oxidation degradation masterbatch;

[0079] The mass fraction of ammonium persulfate in the ammonium persulfate aqueous solution is 10%;

[0080] The weight average molecular weight of the polylactic acid is 100,000;

[0081] Among them, the weight ratio of the mixed fiber, N,N'-methylenebisacrylamide, acrylic acid, water, tannic acid, sodium alginate, and ammonium persulfate aqueous solution is 1100:0.7:320:1200:32:22:2.5;

[0082] The weight ratio of the hydrogel powder, zinc chloride, anatase titanium dioxide, and dopamine hydrochloride is 110:13:8:3;

[0083] The weight ratio of polylactic acid, modified hydrogel powder, and chitosan is 80:30:7;

[0084] 2. Preparation of the soft masterbatch: Add the acetone solution of maleic anhydride, polylactic acid, diisopropylbenzene peroxide, styrene, and sodium methacrylate to a high-speed mixer and mix evenly. Then, place it at 65°C to completely volatilize the acetone, and then add it to a twin-screw extruder for the first melt extrusion. Control the processing temperature of the twin-screw extruder to be 190°C. After the first melt extrusion, a mixture is obtained; add the mixture and erucamide to the twin-screw extruder for the second melt extrusion. Control the processing temperature of the twin-screw extruder to be 195°C. After the second melt extrusion, a soft masterbatch is obtained;

[0085] The weight-average molecular weight of the polylactic acid is 100,000;

[0086] In the acetone solution of maleic anhydride, the weight ratio of maleic anhydride to acetone is 1:2;

[0087] Among them, the weight ratio of the acetone solution of maleic anhydride, polylactic acid, diisopropylbenzene peroxide, styrene, sodium methacrylate, and erucamide is 75:4200:5:5:24:35;

[0088] 3. Preparation of the s-layer spinning: Add polypropylene, high-melt-index polypropylene, PE-PP block copolymer, oxidative degradation masterbatch, soft masterbatch, and white masterbatch to a high-speed mixer in a weight ratio of 80:8:20:10:1.5:2.5 and mix evenly. Then, add it to a twin-screw extruder for melt extrusion. Control the processing temperature of the twin-screw extruder to be 220°C. After melt extrusion, perform melt metering, die spinning, and drawing treatments to obtain the s-layer spinning;

[0089] The MFR of the polypropylene at 230°C and 2.16 kg is 40 g / 10 min;

[0090] The MFR of the high-melt-index polypropylene at 230°C and 2.16 kg is 1500 g / 10 min;

[0091] The MFR of the PE-PP block copolymer at 230°C and 2.16 kg is 40 g / 10 min;

[0092] The white masterbatch, by weight, comprises: 90 parts of polyethylene, 40 parts of titanium dioxide, and 8 parts of maleic anhydride grafted polypropylene wax;

[0093] The polyethylene has an MFR of 2 g / 10 min at 230 °C and 2.16 kg;

[0094] 4. Preparing m-layer spun yarn: Mix high melt index polypropylene and oxidation degradation masterbatch in a high-speed mixer in a weight ratio of 95:10, then add them into a twin-screw extruder for melt extrusion. Control the processing temperature of the twin-screw extruder at 250 °C. After melt extrusion, conduct melt metering, die head spinning, and drawing treatments to obtain m-layer spun yarn;

[0095] The high melt index polypropylene has an MFR of 1500 g / 10 min at 230 °C and 2.16 kg;

[0096] 5. Hot rolling and slitting: Separate and lay the s-layer spun yarn and m-layer spun yarn into a web. From top to bottom, it is s-layer, s-layer, m-layer, m-layer, s-layer. After the web laying is completed, conduct hot rolling treatment and humidification treatment simultaneously. Control the temperature of the patterned roll in the hot rolling treatment at 155 °C, the temperature of the smooth roll at 145 °C, the speed of the mesh belt at 590 m / min, and the hot rolling pressure at 90 daN / cm; After the hot rolling and humidification treatments are completed, conduct drying, winding, and slitting to obtain the degradable polypropylene spunbond nonwoven fabric.

[0097] Comparative Example 1

[0098] Use the same preparation method of the degradable polypropylene spunbond nonwoven fabric as in Example 2, the difference is that: change the step of preparing the oxidation degradation masterbatch in the first step to:

[0099] Crush bamboo fiber and ramie fiber to 400 mesh respectively, then mix them evenly in a weight ratio of 9:1 to obtain mixed fiber; Mix the mixed fiber, zinc chloride, anatase titanium dioxide, and dopamine hydrochloride and conduct ball milling. Control the ball-to-material ratio during ball milling at 9:1, the rotation speed at 310 rpm, and the time at 22 min. After the ball milling is completed, obtain the modified fiber powder; Add polylactic acid, modified fiber powder, and chitosan into a twin-screw extruder for melt extrusion. Control the processing temperature of the twin-screw extruder at 185 °C. After the melt extrusion is completed, conduct pelletizing to obtain the oxidation degradation masterbatch;

[0100] The polylactic acid has a weight average molecular weight of 80,000;

[0101] Among them, the weight ratio of the mixed fiber, zinc chloride, anatase titanium dioxide, and dopamine hydrochloride is 105:12:7:2.5;

[0102] The weight ratio of polylactic acid, modified fiber powder, and chitosan is 75:25:5.

[0103] Comparative Example 2

[0104] The same preparation method of the degradable polypropylene spunbond nonwoven fabric as in Example 2 was adopted, and the difference was that: the step of preparing the soft masterbatch in the second step was changed to:

[0105] Polylactic acid and erucamide were added to a twin-screw extruder for melt extrusion, and the processing temperature of the twin-screw extruder was controlled at 190 °C. After the melt extrusion was completed, a soft masterbatch was obtained;

[0106] The weight-average molecular weight of the polylactic acid was 80,000;

[0107] Among them, the weight ratio of polylactic acid to erucamide was 4100:32.

[0108] Test Example 1

[0109] 200 g of the degradable polypropylene spunbond nonwoven fabrics prepared in Examples 1-3 and Comparative Examples 1-2 were respectively taken and buried in the soil at a depth of 15 cm on the ground surface. The soil moisture content was 10.23% and the pH was 6.5. After 5 months, the degradable polypropylene spunbond nonwoven fabrics were taken out and weighed respectively as the weight after biodegradation, and then the weight loss rate after biodegradation was calculated. The calculation formula and calculation results are as follows:

[0110] Weight loss rate after biodegradation = (200 - weight after biodegradation) / 200 × 100%

[0111]

[0112] As can be seen from the above results, by making bamboo fiber and ramie fiber into aerogel powder when preparing the oxidation degradation masterbatch, the biodegradation speed of the prepared degradable polypropylene spunbond nonwoven fabric can be improved.

[0113] Test Example 2

[0114] The MD strength, CD strength, MD elongation, CD elongation, MD softness, and CD softness of the degradable polypropylene spunbond nonwoven fabrics prepared in Examples 1-3 and Comparative Examples 1-2 were tested, and the test results are as follows:

[0115]

[0116] As can be seen from the above results, by making bamboo fiber and ramie fiber into aerogel powder when preparing the oxidation degradation masterbatch, the MD strength, CD strength, MD elongation, and CD elongation of the prepared degradable polypropylene spunbond nonwoven fabric can be improved; by grafting and modifying polylactic acid when preparing the soft masterbatch, the MD softness and CD softness of the prepared degradable polypropylene spunbond nonwoven fabric can be improved.

[0117] Test Example 3

[0118] The degradable polypropylene spunbond nonwovens prepared in Examples 1-3 and Comparative Examples 1-2 were continuously irradiated under a xenon lamp for 10 days. The power of the xenon lamp was controlled at 35 W, and the temperature during irradiation was 20 °C. After irradiation, the MD strength, CD strength, MD elongation, and CD elongation of the degradable polypropylene spunbond nonwovens were tested. The test results are as follows:

[0119]

[0120] Test Example 4

[0121] The degradable polypropylene spunbond nonwovens prepared in Examples 1-3 and Comparative Examples 1-2 were heat-treated at 50 °C for 10 d, and then the MD strength, CD strength, MD elongation, and CD elongation of the degradable polypropylene spunbond nonwovens were tested. The test results are as follows:

[0122]

[0123] It can be seen from the results of Test Example 3 and Test Example 4 that by making bamboo fiber and ramie fiber into aerogel powder when preparing the oxidation degradation masterbatch, and graft-modifying polylactic acid when preparing the soft masterbatch, the ultraviolet resistance and high-temperature resistance of the prepared degradable polypropylene spunbond nonwovens can be improved.

[0124] Unless otherwise specified, the percentages used in the present invention are all weight percentages, and the ratios described in the present invention are all mass ratios.

[0125] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A preparation method of a degradable polypropylene spunbond non-woven fabric, characterized in that, Including: Preparing an oxidation-degradable masterbatch, preparing a soft masterbatch, preparing an s-layer spun fiber, preparing an m-layer spun fiber, hot rolling, and slitting; For the preparation of the oxidation-degradable masterbatch, bamboo fibers and ramie fibers are respectively crushed to 300-500 mesh, and then mixed evenly according to a weight ratio of 8-10:1 to obtain mixed fibers; the mixed fibers, N,N'-methylenebisacrylamide, acrylic acid, and water are mixed and stirred at 35-40 °C, tannic acid and sodium alginate are added, stirred, the temperature is raised to 50-55 °C, and stirring continues. Then the stirring speed is increased, and an aqueous ammonium persulfate solution is added dropwise while stirring. After the addition is completed, stirring continues, and then it is left standing at 60-65 °C and then freeze-dried. After the freeze-drying is completed, a hydrogel powder is obtained; the hydrogel powder, zinc chloride, anatase titanium dioxide, and dopamine hydrochloride are mixed and ball-milled to obtain a modified hydrogel powder; polylactic acid, the modified hydrogel powder, and chitosan are added to a twin-screw extruder for melt extrusion and pelletizing to obtain the oxidation-degradable masterbatch; For the preparation of the soft masterbatch, an acetone solution of maleic anhydride, polylactic acid, diisopropylbenzene peroxide, styrene, and sodium methacrylate are mixed evenly in a high-speed mixer, and then the acetone is completely volatilized. Then it is added to a twin-screw extruder for the first melt extrusion. After the first melt extrusion is completed, a mixture is obtained; the mixture and erucamide are added to a twin-screw extruder for the second melt extrusion. After the second melt extrusion is completed, the soft masterbatch is obtained; For the preparation of the s-layer spun fiber, polypropylene, high-melt-index polypropylene, a PE-PP block copolymer, the oxidation-degradable masterbatch, the soft masterbatch, and a white masterbatch are mixed evenly in a high-speed mixer according to a weight ratio of 75-80:5-8:18-20:8-10:1-1.5:1.5-2.

5. Then it is added to a twin-screw extruder for melt extrusion. After melt extrusion, melt metering, die spinning, and drawing treatments are carried out to obtain the s-layer spun fiber; For the preparation of the m-layer spun fiber, high-melt-index polypropylene and the oxidation-degradable masterbatch are mixed evenly in a high-speed mixer according to a weight ratio of 90-95:5-10. Then it is added to a twin-screw extruder for melt extrusion. After melt extrusion, melt metering, die spinning, and drawing treatments are carried out to obtain the m-layer spun fiber; In the preparation of the m-layer spun fiber, the MFR of the high-melt-index polypropylene at 230 °C and 2.16 kg is 800-1500 g / 10 min; For the hot rolling and slitting, the s-layer spun fiber and the m-layer spun fiber are split and laid into a web. From top to bottom, they are the s-layer, s-layer, m-layer, m-layer, and s-layer. After the web laying is completed, hot rolling treatment and humidification treatment are carried out simultaneously. After the hot rolling and humidification treatments are completed, drying, winding, and slitting are carried out to obtain a degradable polypropylene spunbond nonwoven fabric; In the hot rolling and slitting, the temperature of the patterned roll in the hot rolling treatment is 140-155 °C, the temperature of the smooth roll is 135-150 °C, the speed of the mesh belt is 450-600 m / min, and the hot rolling pressure is 70-100 daN / cm.

2. The preparation method of the degradable polypropylene spunbond non-woven fabric according to claim 1, characterized in that, In the preparation of the oxidation-degradable masterbatch, the mass fraction of ammonium persulfate in the aqueous ammonium persulfate solution is 8-10%; The weight-average molecular weight of the polylactic acid is 50,000 - 100,000.

3. The preparation method of the degradable polypropylene spunbond non-woven fabric according to claim 1, characterized in that, In the preparation of the oxidation-degradable masterbatch, the dropping rate of the ammonium persulfate aqueous solution is 25 - 30 g / min; During the freeze-drying, the temperature is -40°C to -30°C and the time is 8 - 9 h; During the ball milling, the ball-to-material ratio is 8 - 10:1, the rotation speed is 300 - 320 rpm, and the time is 20 - 25 min.

4. The preparation method of the degradable polypropylene spunbond non-woven fabric according to claim 1, characterized in that, In the preparation of the oxidation-degradable masterbatch, the weight ratio of the mixed fiber, N,N'-methylenebisacrylamide, acrylic acid, water, tannic acid, sodium alginate, and ammonium persulfate aqueous solution is 1000 - 1100:0.6 - 0.7:300 - 320:1100 - 1200:30 - 32:20 - 22:2 - 2.5; The weight ratio of the hydrogel powder, zinc chloride, anatase titanium dioxide, and dopamine hydrochloride is 100 - 110:10 - 13:6 - 8:2 - 3; The weight ratio of the polylactic acid, modified hydrogel powder, and chitosan is 70 - 80:20 - 30:4 - 7.

5. The preparation method of the degradable polypropylene spunbond non-woven fabric according to claim 1, characterized in that, In the preparation of the soft masterbatch, the weight-average molecular weight of the polylactic acid is 50,000 - 100,000; In the acetone solution of maleic anhydride, the weight ratio of maleic anhydride to acetone is 1:1.5 - 2.

6. The preparation method of the degradable polypropylene spunbond non-woven fabric according to claim 1, characterized in that, In the preparation of the soft masterbatch, the weight ratio of the acetone solution of maleic anhydride, polylactic acid, dicumyl peroxide, styrene, sodium methacrylate, and erucamide is 70 - 75:4000 - 4200:3 - 5:4 - 5:20 - 24:30 - 35; 7. The preparation method of the degradable polypropylene spunbond non-woven fabric according to claim 1, characterized in that, In the preparation of the s-layer spinning, the MFR of the polypropylene at 230°C and 2.16 kg is 32 - 40 g / 10 min; The MFR of the high melt index polypropylene at 230°C and 2.16 kg is 800 - 1500 g / 10 min; The MFR of the PE-PP block copolymer at 230°C and 2.16 kg is 32 - 40 g / 10 min; The white masterbatch, by weight, comprises: 80 - 90 parts of polyethylene, 30 - 40 parts of titanium dioxide, and 5 - 8 parts of maleic anhydride grafted polypropylene wax; The MFR of the polyethylene at 230°C and 2.16 kg is 1 - 2 g / 10 min.

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