A method for preparing degradable composite polypropylene non-woven fabric

Abstract

The invention discloses a preparation method of a degradable composite polypropylene non-woven fabric, which belongs to the technical field of composite polypropylene non-woven fabrics. The preparation method comprises: preparing a degradation masterbatch, preparing a reinforcement masterbatch, preparing an S-layer spinning, preparing an M-layer spinning, hot rolling, and post-processing; in the post-processing, a surface treatment liquid is uniformly sprayed on the surface of the primary degradable composite polypropylene non-woven fabric, and the amount of the surface treatment liquid is controlled to be 20-25 g / m 2 After spraying, the surface is dried at 70-75°C to obtain a degradable composite polypropylene non-woven fabric; in the post-treatment, the surface treatment liquid comprises, by weight: 2-3 parts of chitosan oligosaccharide, 3-4 parts of water-soluble nano titanium dioxide, and 100-110 parts of deionized water; the degradable composite polypropylene non-woven fabric prepared by the present invention has good hygroscopicity, high temperature resistance, aging resistance, and softness, is not easy to delaminate at low temperatures, has high strength, and its degradability is less affected by soil conditions.

Description

Technical Field

[0001] The invention relates to the technical field of composite polypropylene non-woven fabrics, and in particular to a method for preparing a degradable composite polypropylene non-woven fabric. Background Art

[0002] Non-woven fabric, also known as non-woven fabric, needle-punched cotton, needle-punched non-woven fabric, etc., is made through a needle-punching process and can be made into different thicknesses, feels, hardness, etc. It is moisture-proof, breathable, flexible, thin, flame-retardant, non-toxic and odorless, low-priced, recyclable, etc. It can be used in different industries, such as sound insulation, heat insulation, electric heaters, masks, clothing, medical, filling materials, etc.

[0003] Polypropylene is one of the most commonly used materials for non-woven fabrics. It has light texture, high strength, good corrosion resistance, air permeability and wear resistance, but poor moisture absorption, high temperature resistance and aging resistance, and is non-degradable, causing great harm to the environment.

[0004] In order to overcome the shortcomings of polypropylene non-woven fabrics, the most commonly used method at present is to compound multiple layers of polypropylene non-woven fabrics or perform special treatment on polypropylene non-woven fabrics to make composite polypropylene non-woven fabrics with good hygroscopicity, air permeability, wear resistance, high temperature resistance and aging resistance. At the same time, in order to improve the degradability of the composite polypropylene non-woven fabrics, biodegradation promoters are also added. However, the composite polypropylene non-woven fabrics obtained by compounding multiple layers of polypropylene non-woven fabrics are easy to delaminate at low temperatures and have poor softness, while the composite polypropylene non-woven fabrics obtained after special treatment have low strength, and the degradability obtained by adding biodegradation promoters is greatly affected by soil conditions. The moisture content and pH value of the soil will affect the degradation rate. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a method for preparing a degradable composite polypropylene non-woven fabric. The prepared degradable composite polypropylene non-woven fabric has good hygroscopicity, high temperature resistance, aging resistance, and softness, is not easy to delaminate at low temperatures, has high strength, and its degradability is less affected by soil conditions.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing a degradable composite polypropylene non-woven fabric, comprising: preparing a degradation masterbatch, preparing a reinforcement masterbatch, preparing an S-layer spinning, preparing an M-layer spinning, hot rolling, and post-processing;

[0008] The method for preparing the degradation masterbatch comprises: adding an ethanol solution of zinc acetate and an ethanol solution of sodium hydroxide to a reactor, controlling the temperature of the reactor to 2-5° C., controlling the stirring speed to 100-120 rpm, stirring for 0.5-1 h, slowly dripping an ethanol solution of magnesium acetate, controlling the temperature of the reactor to 30-35° C. after the dripping, continuing to stir for 10-15 min, adding a modification liquid, continuing to stir for 2-3 h, adding n-hexane, continuing to stir for 0.5-1 h, centrifuging, controlling the speed of centrifugation to 7000-9000 rpm, and drying the centrifugation time to 6-8 min, and drying the precipitate at 80-90° C. after the centrifugation to obtain modified quantum dots; adding polylactic acid, modified quantum dots, and polyethylene wax to a twin-screw extruder for melt extrusion, controlling the processing temperature of the twin-screw extruder to 175-185° C., and pelletizing after the melt extrusion to obtain the degradation masterbatch;

[0009] In the preparation of the degradation masterbatch, the weight ratio of the zinc acetate ethanol solution, the sodium hydroxide ethanol solution, the magnesium acetate ethanol solution, the modification liquid, and n-hexane is 30-40:15-20:10-15:40-50:140-160;

[0010] The modified liquid comprises, by weight, 5-6 parts of γ-aminopropyltriethoxysilane, 2-3 parts of sodium alginate, 1-1.5 parts of polyethylene glycol diacrylate, and 100-105 parts of deionized water;

[0011] The weight ratio of polylactic acid, modified quantum dots and polyethylene wax is 90-95:8-10:2-3;

[0012] The mass fraction of the zinc acetate ethanol solution is 2-2.5%;

[0013] The mass fraction of the sodium hydroxide ethanol solution is 2-2.5%;

[0014] The mass fraction of the magnesium acetate ethanol solution is 0.8-1%, and the dropping speed is 10-12 g / min;

[0015] The weight average molecular weight of the polylactic acid is 80,000-150,000;

[0016] The preparation of the enhanced masterbatch comprises adding polylactic acid, light calcium carbonate, kaolin, γ-aminopropyl triethoxysilane and nano zinc oxide into a twin-screw extruder for melt extrusion, controlling the processing temperature of the twin-screw extruder to be 175-185° C., and pelletizing after the melt extrusion to obtain the degradation masterbatch;

[0017] The weight ratio of polylactic acid, light calcium carbonate, kaolin, γ-aminopropyltriethoxysilane and nano zinc oxide is 70-75:5-8:5-10:0.5-1;

[0018] The weight average molecular weight of the polylactic acid is 80,000-150,000;

[0019] The particle size of the nano zinc oxide is 50-100 nm;

[0020] The S-layer spinning is prepared by adding polypropylene, high melt index polypropylene, PE-PP block copolymer, degradation masterbatch, reinforcement masterbatch and white masterbatch into a high-speed mixer according to a weight ratio of 85-90:4-6:12-15:10-12:5-8:2-2.5 and mixing them evenly, then adding them into a twin-screw extruder for melt extrusion, controlling the processing temperature of the twin-screw extruder to be 185-200° C., and performing melt metering, die head spinning and drafting treatment after melt extrusion to obtain S-layer spinning;

[0021] 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;

[0022] The high melt index polypropylene has an MFR of 800-1500 g / 10 min at 230° C. and 2.16 kg;

[0023] The MFR of the PE-PP block copolymer at 230° C. and 2.16 kg is 32-40 g / 10 min;

[0024] The white masterbatch comprises, by weight: 80-90 parts of polyethylene, 25-30 parts of titanium dioxide, and 3-5 parts of polyethylene wax;

[0025] The MFR of the polyethylene at 230° C. and 2.16 kg is 1-2 g / 10 min;

[0026] The m-layer spinning is prepared by adding high melt index polypropylene and degradation masterbatch in a weight ratio of 90-95:10-15 into a high-speed mixer and mixing them evenly, adding them into a twin-screw extruder for melt extrusion, controlling the processing temperature of the twin-screw extruder to be 200-210° C., and performing melt metering, die head spinning and drafting after melt extrusion to obtain the m-layer spinning;

[0027] In the preparation of the m-layer spinning, the MFR of the high melt index polypropylene at 230° C. and 2.16 kg is 800-1500 g / 10 min;

[0028] The hot rolling is to separate the s-layer spinning and the m-layer spinning into a web, which are s-layer, m-layer, m-layer, and s-layer from top to bottom, and hot rolling treatment and humidification treatment are performed at the same time after the web laying is completed, and the temperature of the flower roller in the hot rolling treatment is controlled to be 155-160° C., and the temperature of the smooth roller is controlled to be 145-150° C., and the primary degradable composite polypropylene non-woven fabric is obtained after the hot rolling is completed;

[0029] The post-treatment comprises spraying the surface treatment liquid uniformly on the surface of the primary degradable composite polypropylene non-woven fabric, and controlling the amount of the surface treatment liquid to be 20-25 g / m 2 After spraying, it is placed in a drying condition at 70-75°C to obtain a degradable composite polypropylene non-woven fabric;

[0030] In the post-treatment, the surface treatment liquid comprises, by weight: 2-3 parts of chitosan oligosaccharide, 3-4 parts of water-soluble nano titanium dioxide, and 100-110 parts of deionized water;

[0031] The preparation method of the water-soluble nano titanium dioxide is as follows: adding nano titanium dioxide, acrylamide and acetone into a closed reactor, evacuating the closed reactor to a vacuum degree of 0.08-0.09 MPa, then introducing nitrogen until the gas pressure is 0.2-0.25 MPa, controlling the temperature of the closed reactor to 40-45° C., controlling the stirring speed to 100-150 rpm, stirring for 30-40 minutes and then pouring out, irradiating with ultraviolet light, and then centrifuging, controlling the speed of centrifugation to 8000-10000 rpm, the time to be 5-6 minutes, and drying the precipitate at 70-80° C. after the centrifugation to obtain water-soluble nano titanium dioxide;

[0032] In the preparation of the water-soluble nano titanium dioxide, the wavelength of ultraviolet light irradiation is 320-380nm, the temperature is 40-45°C, and the time is 40-45min;

[0033] The particle size of the nano titanium dioxide is 10-50nm.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] (1) The method for preparing the degradable composite polypropylene non-woven fabric of the present invention can improve the hygroscopicity of the degradable composite polypropylene non-woven fabric by post-treating the primary degradable composite polypropylene non-woven fabric. The water absorption rate of the degradable composite polypropylene non-woven fabric prepared by the present invention can reach 121.5-125.4%;

[0036] (2) The method for preparing the degradable composite polypropylene non-woven fabric of the present invention can improve the softness of the degradable composite polypropylene non-woven fabric by post-treating the primary degradable composite polypropylene non-woven fabric. The MD softness of the degradable composite polypropylene non-woven fabric prepared by the present invention is 3.1-3.4g, and the CD softness is 1.5-1.8g;

[0037] (3) The preparation method of the degradable composite polypropylene non-woven fabric of the present invention can improve the strength of the degradable composite polypropylene non-woven fabric by post-treating the primary degradable composite polypropylene non-woven fabric. The MD strength of the degradable composite polypropylene non-woven fabric prepared by the present invention is 28.7-29.8N / 5cm, and the CD strength is 16.4-17.3N / 5cm;

[0038] (4) The preparation method of the degradable composite polypropylene non-woven fabric of the present invention can improve the high temperature resistance of the degradable composite polypropylene non-woven fabric by adding degradation masterbatch. The degradable composite polypropylene non-woven fabric prepared by the present invention is placed at 50°C for 100 days, and the MD strength is 28.5-29.7N / 5cm, and the CD strength is 16.1-17.0N / 5cm;

[0039] (5) The preparation method of the degradable composite polypropylene non-woven fabric of the present invention can improve the aging resistance of the degradable composite polypropylene non-woven fabric by adding a degradation masterbatch. The degradable composite polypropylene non-woven fabric prepared by the present invention is continuously irradiated under a xenon lamp for 100 days, and the MD strength is 28.4-29.5N / 5cm, and the CD strength is 16.0-17.1N / 5cm;

[0040] (6) The method for preparing the degradable composite polypropylene non-woven fabric of the present invention can prevent the prepared degradable composite polypropylene non-woven fabric from being delaminated at low temperatures by post-treating the primary degradable composite polypropylene non-woven fabric. The degradable composite polypropylene non-woven fabric prepared by the present invention was placed at -30°C for 100 days without delamination.

[0041] (7) The preparation method of the degradable composite polypropylene non-woven fabric of the present invention can reduce the influence of soil conditions on the degradability of the degradable composite polypropylene non-woven fabric by adding degradation masterbatch. The degradable composite polypropylene non-woven fabric prepared by the present invention is buried in soil with a surface depth of 15 cm, the soil moisture content is 8%, the pH is 6, and the weight loss rate after 5 months is 30.1-32.4%; the degradable composite polypropylene non-woven fabric prepared by the present invention is buried in soil with a surface depth of 15 cm, the soil moisture content is 14%, the pH is 7, and the weight loss rate after 5 months is 30.2-32.5%; the degradable composite polypropylene non-woven fabric prepared by the present invention is buried in soil with a surface depth of 15 cm, the soil moisture content is 20%, the pH is 8, and the weight loss rate after 5 months is 29.8-32.2%. DETAILED DESCRIPTION

[0042] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific implementation methods of the present invention are now described.

[0043] Example 1

[0044] A method for preparing a degradable composite polypropylene non-woven fabric, specifically comprising:

[0045] 1. Preparation of degradation masterbatch: Add 2% zinc acetate ethanol solution and 2% sodium hydroxide ethanol solution to a reactor, control the temperature of the reactor to 2°C, control the stirring speed to 100rpm, stir for 0.5h, slowly drip 0.8% magnesium acetate ethanol solution, control the dripping speed to 10g / min, control the temperature of the reactor to 30-35°C after the dripping, continue stirring for 10min, add the modified liquid, continue stirring for 2h, add n-hexane, continue stirring for 0.5h, centrifuge, control the speed of centrifugation to 7000rpm, the time is 6min, and after the centrifugation, dry the precipitate at 80-90°C to obtain modified quantum dots; add polylactic acid, modified quantum dots, and polyethylene wax to a twin-screw extruder for melt extrusion, control the processing temperature of the twin-screw extruder to 175°C, and pelletize after the melt extrusion to obtain degradation masterbatch;

[0046] The weight ratio of zinc acetate ethanol solution, sodium hydroxide ethanol solution, magnesium acetate ethanol solution, modification liquid and n-hexane is 30:15:10:40:140;

[0047] The composition of the modified liquid, by weight, includes: 5 parts of γ-aminopropyltriethoxysilane, 2 parts of sodium alginate, 1 part of polyethylene glycol diacrylate, and 100 parts of deionized water;

[0048] The weight ratio of polylactic acid, modified quantum dots, and polyethylene wax is 90:8:2;

[0049] The weight average molecular weight of the polylactic acid is 80,000;

[0050] 2. Preparation of enhanced masterbatch: adding polylactic acid, light calcium carbonate, kaolin, γ-aminopropyl triethoxysilane and nano zinc oxide into a twin-screw extruder for melt extrusion, controlling the processing temperature of the twin-screw extruder to be 175°C, and pelletizing after the melt extrusion to obtain a degradation masterbatch;

[0051] The weight ratio of polylactic acid, light calcium carbonate, kaolin, γ-aminopropyltriethoxysilane, and nano zinc oxide is 70:5:5:0.5;

[0052] The weight average molecular weight of the polylactic acid is 80,000;

[0053] The particle size of the nano zinc oxide is 50nm;

[0054] 3. Preparation of S-layer spinning: polypropylene, high melt index polypropylene, PE-PP block copolymer, degradation masterbatch, reinforcement masterbatch, and white masterbatch are added to a high-speed mixer in a weight ratio of 85:4:12:10:5:2 and mixed evenly, and then added to a twin-screw extruder for melt extrusion. The processing temperature of the twin-screw extruder is controlled to be 185° C. After melt extrusion, melt metering, die head spinning, and drafting treatment are performed to obtain S-layer spinning;

[0055] In the preparation of the s-layer spinning, the MFR of the polypropylene at 230° C. and 2.16 kg is 32 g / 10 min;

[0056] The high melt index polypropylene has an MFR of 800 g / 10 min at 230° C. and 2.16 kg;

[0057] The MFR of the PE-PP block copolymer at 230° C. and 2.16 kg is 32 g / 10 min;

[0058] The white masterbatch comprises, by weight: 80 parts of polyethylene, 25 parts of titanium dioxide, and 3 parts of polyethylene wax;

[0059] The MFR of the polyethylene at 230° C. and 2.16 kg is 1 g / 10 min;

[0060] 4. Preparation of m-layer spinning: adding high melt index polypropylene and degradation masterbatch in a weight ratio of 90-95:10-15 into a high-speed mixer and mixing evenly, adding into a twin-screw extruder for melt extrusion, controlling the processing temperature of the twin-screw extruder to be 200° C., and performing melt metering, die head spinning and drafting after melt extrusion to obtain m-layer spinning;

[0061] In the preparation of the m-layer spinning, the MFR of the high melt index polypropylene at 230° C. and 2.16 kg is 800 g / 10 min;

[0062] 5. Hot rolling: Spinning the s-layer and m-layer fibers separately, from top to bottom, are s-layer, m-layer, m-layer, s-layer. After the web laying, hot rolling and humidification treatment are carried out at the same time. The temperature of the flower roller in the hot rolling treatment is controlled to be 155°C, and the temperature of the smooth roller is 145°C. After the hot rolling, the primary biodegradable composite polypropylene non-woven fabric is obtained;

[0063] 6. Post-treatment: Spray the surface treatment liquid evenly on the surface of the primary biodegradable composite polypropylene non-woven fabric, and control the amount of surface treatment liquid to 20g / m 2 After spraying, it is placed at 70°C for drying to obtain a degradable composite polypropylene non-woven fabric;

[0064] The surface treatment liquid comprises, by weight: 2 parts of chitosan oligosaccharide, 3 parts of water-soluble nano titanium dioxide, and 100 parts of deionized water;

[0065] The preparation method of the water-soluble nano titanium dioxide is as follows: nano titanium dioxide, acrylamide and acetone are added into a closed reactor, the closed reactor is evacuated to a vacuum degree of 0.08MPa, nitrogen is introduced until the gas pressure is 0.2MPa, the temperature of the closed reactor is controlled to 40°C, the stirring speed is controlled to 100rpm, the reactor is stirred for 30min and then poured out, ultraviolet light is irradiated, the wavelength of the ultraviolet light is controlled to be 320nm, the temperature is controlled to be 40°C, and the time is controlled to be 40min, then centrifuged, the speed of centrifugation is controlled to be 8000rpm, and the time is controlled to be 5min. After the centrifugation is completed, the precipitate is dried at 70°C to obtain the water-soluble nano titanium dioxide.

[0066] The particle size of the nano titanium dioxide is 10 nm.

[0067] Example 2

[0068] A method for preparing a degradable composite polypropylene non-woven fabric, specifically comprising:

[0069] 1. Preparation of degradation masterbatch: Add 2.2% zinc acetate ethanol solution and 2.2% sodium hydroxide ethanol solution to a reactor, control the temperature of the reactor to 3°C, control the stirring speed to 110rpm, stir for 0.8h, slowly drop 0.9% magnesium acetate ethanol solution, control the dropping speed to 11g / min, control the temperature of the reactor to 32°C after the dropwise addition, continue stirring for 12min, add the modified liquid, continue stirring for 2.5h, add n-hexane, continue stirring for 0.8h, centrifuge, control the speed of centrifugation to 8000rpm, the time is 7min, and after the centrifugation, dry the precipitate at 85°C to obtain modified quantum dots; add polylactic acid, modified quantum dots, and polyethylene wax to a twin-screw extruder for melt extrusion, control the processing temperature of the twin-screw extruder to 180°C, and pelletize after the melt extrusion to obtain degradation masterbatch;

[0070] The weight ratio of zinc acetate ethanol solution, sodium hydroxide ethanol solution, magnesium acetate ethanol solution, modification liquid and n-hexane is 35:18:12:45:150;

[0071] The composition of the modified liquid, by weight, includes: 5.5 parts of γ-aminopropyltriethoxysilane, 2.5 parts of sodium alginate, 1.2 parts of polyethylene glycol diacrylate, and 102 parts of deionized water;

[0072] The weight ratio of polylactic acid, modified quantum dots, and polyethylene wax is 92:9:2.5;

[0073] The weight average molecular weight of the polylactic acid is 100,000;

[0074] 2. Preparation of enhanced masterbatch: adding polylactic acid, light calcium carbonate, kaolin, γ-aminopropyl triethoxysilane and nano zinc oxide into a twin-screw extruder for melt extrusion, controlling the processing temperature of the twin-screw extruder to be 180°C, and pelletizing after the melt extrusion to obtain a degradation masterbatch;

[0075] The weight ratio of polylactic acid, light calcium carbonate, kaolin, γ-aminopropyltriethoxysilane, and nano zinc oxide is 72:6:8:0.8;

[0076] The weight average molecular weight of the polylactic acid is 100,000;

[0077] The particle size of the nano zinc oxide is 80nm;

[0078] 3. Preparation of S-layer spinning: polypropylene, high melt index polypropylene, PE-PP block copolymer, degradation masterbatch, reinforcement masterbatch, and white masterbatch are added to a high-speed mixer in a weight ratio of 88:5:13:11:7:2.2 and mixed evenly, and then added to a twin-screw extruder for melt extrusion. The processing temperature of the twin-screw extruder is controlled to be 188° C. After melt extrusion, melt metering, die head spinning and drafting are performed to obtain S-layer spinning;

[0079] In the preparation of the s-layer spinning, the MFR of the polypropylene at 230° C. and 2.16 kg is 35 g / 10 min;

[0080] The high melt index polypropylene has an MFR of 1000 g / 10 min at 230° C. and 2.16 kg;

[0081] The MFR of the PE-PP block copolymer at 230° C. and 2.16 kg is 35 g / 10 min;

[0082] The white masterbatch comprises, by weight: 85 parts of polyethylene, 28 parts of titanium dioxide, and 4 parts of polyethylene wax;

[0083] The MFR of the polyethylene at 230° C. and 2.16 kg is 1.5 g / 10 min;

[0084] 4. Preparation of m-layer spinning: adding high melt index polypropylene and degradation masterbatch in a weight ratio of 92:12 into a high-speed mixer and mixing them evenly, adding them into a twin-screw extruder for melt extrusion, controlling the processing temperature of the twin-screw extruder to be 205° C., and performing melt metering, die head spinning and drafting after melt extrusion to obtain m-layer spinning;

[0085] In the preparation of the m-layer spinning, the MFR of the high melt index polypropylene at 230° C. and 2.16 kg is 1000 g / 10 min;

[0086] 5. Hot rolling: the s-layer spinning and the m-layer spinning are separated and laid, and from top to bottom they are s-layer, m-layer, m-layer, and s-layer, respectively. After the laying, hot rolling treatment and humidification treatment are carried out at the same time. The temperature of the flower roller in the hot rolling treatment is controlled to be 158°C, and the temperature of the smooth roller is controlled to be 148°C. After the hot rolling, the primary degradable composite polypropylene non-woven fabric is obtained;

[0087] 6. Post-treatment: Spray the surface treatment liquid evenly on the surface of the primary biodegradable composite polypropylene non-woven fabric, and control the amount of the surface treatment liquid to 22g / m 2 After spraying, it is placed at 72°C for drying to obtain a degradable composite polypropylene non-woven fabric;

[0088] The surface treatment liquid comprises, by weight: 2.5 parts of chitosan oligosaccharide, 3.5 parts of water-soluble nano titanium dioxide, and 105 parts of deionized water;

[0089] The preparation method of the water-soluble nano titanium dioxide is as follows: nano titanium dioxide, acrylamide and acetone are added into a closed reactor, the closed reactor is evacuated to a vacuum degree of 0.085 MPa, nitrogen is introduced until the gas pressure is 0.22 MPa, the temperature of the closed reactor is controlled to 42° C., the stirring speed is controlled to 120 rpm, the reaction mixture is stirred for 35 minutes and then poured out, ultraviolet light is irradiated, the wavelength of the ultraviolet light is controlled to be 350 nm, the temperature is controlled to be 42° C., and the time is controlled to be 42 minutes, then centrifuged, the speed of the centrifugation is controlled to be 9000 rpm, and the time is controlled to be 5.5 minutes, and after the centrifugation is completed, the precipitate is dried at 75° C. to obtain water-soluble nano titanium dioxide.

[0090] The particle size of the nano titanium dioxide is 30 nm.

[0091] Example 3

[0092] A method for preparing a degradable composite polypropylene non-woven fabric, specifically comprising:

[0093] 1. Preparation of degradation masterbatch: Add 2.5% zinc acetate ethanol solution and 2.5% sodium hydroxide ethanol solution to a reactor, control the temperature of the reactor to 2-5°C, control the stirring speed to 120rpm, and stir for 1h, then slowly drip 1% magnesium acetate ethanol solution, control the dripping speed to 12g / min, and control the temperature of the reactor to 35°C after the dripping, continue stirring for 15min, add the modified liquid, continue stirring for 3h, add n-hexane, continue stirring for 1h, centrifuge, control the speed of centrifugation to 9000rpm, and the time is 8min. After the centrifugation, dry the precipitate at 90°C to obtain modified quantum dots; add polylactic acid, modified quantum dots, and polyethylene wax to a twin-screw extruder for melt extrusion, control the processing temperature of the twin-screw extruder to 185°C, and pelletize after the melt extrusion to obtain degradation masterbatch;

[0094] The weight ratio of zinc acetate ethanol solution, sodium hydroxide ethanol solution, magnesium acetate ethanol solution, modification liquid and n-hexane is 40:20:15:50:160;

[0095] The composition of the modified liquid, by weight, includes: 6 parts of γ-aminopropyltriethoxysilane, 3 parts of sodium alginate, 1.5 parts of polyethylene glycol diacrylate, and 105 parts of deionized water;

[0096] The weight ratio of polylactic acid, modified quantum dots, and polyethylene wax is 95:10:3;

[0097] The weight average molecular weight of the polylactic acid is 150,000;

[0098] 2. Preparation of enhanced masterbatch: adding polylactic acid, light calcium carbonate, kaolin, γ-aminopropyl triethoxysilane and nano zinc oxide into a twin-screw extruder for melt extrusion, controlling the processing temperature of the twin-screw extruder to be 185°C, and pelletizing after the melt extrusion to obtain a degradation masterbatch;

[0099] The weight ratio of polylactic acid, light calcium carbonate, kaolin, γ-aminopropyltriethoxysilane and nano zinc oxide is 75:8:10:1;

[0100] The weight average molecular weight of the polylactic acid is 150,000;

[0101] The particle size of the nano zinc oxide is 100 nm;

[0102] 3. Preparation of S-layer spinning: polypropylene, high melt index polypropylene, PE-PP block copolymer, degradation masterbatch, reinforcement masterbatch, and white masterbatch are added to a high-speed mixer in a weight ratio of 90:6:15:12:8:2.5 and mixed evenly, and then added to a twin-screw extruder for melt extrusion. The processing temperature of the twin-screw extruder is controlled to be 200° C. After melt extrusion, melt metering, die head spinning and drafting are performed to obtain S-layer spinning;

[0103] In the preparation of the s-layer spinning, the MFR of the polypropylene at 230° C. and 2.16 kg is 40 g / 10 min;

[0104] The high melt index polypropylene has an MFR of 1500 g / 10 min at 230° C. and 2.16 kg;

[0105] The MFR of the PE-PP block copolymer at 230° C. and 2.16 kg is 40 g / 10 min;

[0106] The white masterbatch comprises, by weight: 90 parts of polyethylene, 30 parts of titanium dioxide, and 5 parts of polyethylene wax;

[0107] The MFR of the polyethylene at 230° C. and 2.16 kg is 2 g / 10 min;

[0108] 4. Preparation of m-layer spinning: adding high melt index polypropylene and degradation masterbatch in a weight ratio of 90-95:10-15 into a high-speed mixer and mixing evenly, adding into a twin-screw extruder for melt extrusion, controlling the processing temperature of the twin-screw extruder to be 210°C, and performing melt metering, die head spinning and drafting after melt extrusion to obtain m-layer spinning;

[0109] In the preparation of the m-layer spinning, the MFR of the high melt index polypropylene at 230° C. and 2.16 kg is 1500 g / 10 min;

[0110] 5. Hot rolling: Spread the s-layer spinning and the m-layer spinning separately, from top to bottom, they are s-layer, m-layer, m-layer, s-layer, respectively. After the web laying, hot rolling treatment and humidification treatment are carried out at the same time. The temperature of the flower roller in the hot rolling treatment is controlled to be 160°C, and the temperature of the smooth roller is 150°C. After the hot rolling, the primary degradable composite polypropylene non-woven fabric is obtained;

[0111] 6. Post-treatment: Spray the surface treatment liquid evenly on the surface of the primary biodegradable composite polypropylene non-woven fabric, and control the amount of surface treatment liquid to 25g / m 2 After spraying, it is placed at 75°C for drying to obtain a degradable composite polypropylene non-woven fabric;

[0112] The surface treatment liquid comprises, by weight: 3 parts of chitosan oligosaccharide, 4 parts of water-soluble nano titanium dioxide, and 110 parts of deionized water;

[0113] The preparation method of the water-soluble nano titanium dioxide is as follows: nano titanium dioxide, acrylamide and acetone are added into a closed reactor, the closed reactor is evacuated to a vacuum degree of 0.09 MPa, nitrogen is introduced until the gas pressure is 0.25 MPa, the temperature of the closed reactor is controlled to 45°C, the stirring speed is controlled to 150 rpm, the reaction mixture is stirred for 40 minutes and then poured out, ultraviolet light is irradiated, the wavelength of the ultraviolet light is controlled to be 380 nm, the temperature is controlled to be 45°C, and the time is controlled to be 45 minutes, then centrifuged, the speed of centrifugation is controlled to be 10000 rpm, and the time is controlled to be 6 minutes, and after the centrifugation, the precipitate is dried at 80°C to obtain water-soluble nano titanium dioxide.

[0114] The particle size of the nano titanium dioxide is 50 nm.

[0115] Comparative Example 1

[0116] The method for preparing the degradable composite polypropylene non-woven fabric described in Example 2 is adopted, and the difference is that: the step of preparing the degradation masterbatch in step 1 is changed to: adding polylactic acid and polyethylene wax into a twin-screw extruder for melt extrusion, controlling the processing temperature of the twin-screw extruder to 180° C., and pelletizing after the melt extrusion to obtain the degradation masterbatch;

[0117] The weight ratio of polylactic acid to polyethylene wax is 92:2.5;

[0118] The weight average molecular weight of the polylactic acid is 100,000.

[0119] Comparative Example 2

[0120] The method for preparing the degradable composite polypropylene non-woven fabric described in Example 2 is adopted, except that the sixth post-treatment step is omitted.

[0121] Test Example 1

[0122] The water absorption, MD softness, CD softness, MD strength, and CD strength of the degradable composite polypropylene non-woven fabrics prepared in Examples 1-3 and Comparative Examples 1-2 were tested, and the test results are as follows:

[0123]

[0124] It can be seen from the above results that the hygroscopicity, softness and strength of the degradable composite polypropylene non-woven fabric can be improved by post-treating the primary degradable composite polypropylene non-woven fabric.

[0125] Test Example 2

[0126] The degradable composite polypropylene nonwoven fabrics prepared in Examples 1-3 and Comparative Examples 1-2 were placed at 50° C. for 100 days, and then the MD strength and CD strength of the degradable composite polypropylene nonwoven fabrics were tested. The test results are as follows:

[0127]

[0128] It can be seen from the above results that the high temperature resistance of the degradable composite polypropylene non-woven fabric can be improved by adding the degradation masterbatch.

[0129] Test Example 3

[0130] The degradable composite polypropylene nonwoven fabrics prepared in Examples 1-3 and Comparative Examples 1-2 were placed under a xenon lamp for continuous irradiation, the power of the xenon lamp was controlled to be 35W, the continuous irradiation time was 100d, and then the MD strength and CD strength of the degradable composite polypropylene nonwoven fabrics were tested, and the test results were as follows:

[0131]

[0132] It can be seen from the above results that the aging resistance of the degradable composite polypropylene non-woven fabric can be improved by adding the degradation masterbatch.

[0133] Test Example 4

[0134] The degradable composite polypropylene nonwoven fabrics prepared in Example 1-3 and Comparative Example 1-2 were placed at -30°C for 100 days, and then the degradable composite polypropylene nonwoven fabrics were observed to see if there was a delamination phenomenon. The observation results were as follows:

[0135]

[0136] It can be seen from the above results that by post-treating the primary degradable composite polypropylene non-woven fabric, the prepared degradable composite polypropylene non-woven fabric can be prevented from being delaminated at low temperatures.

[0137] Test Example 5

[0138] 200 g of each of the degradable composite polypropylene non-woven fabrics prepared in Examples 1-3 and Comparative Examples 1-2 were taken and buried in soil at a depth of 15 cm from the surface. The soil moisture content was 8% and the pH was 6. After 5 months, the degradable composite polypropylene non-woven fabrics were taken out and weighed respectively as the weight after biodegradation. The weight loss rate after biodegradation was then calculated. The calculation formula and calculation results are as follows:

[0139] Weight loss rate after biodegradation = (200-weight after biodegradation) / 200×100%

[0140]

[0141] Test Example 6

[0142] 200 g of each of the degradable composite polypropylene non-woven fabrics prepared in Examples 1-3 and Comparative Examples 1-2 were taken and buried in soil at a surface depth of 15 cm, respectively. The soil moisture content was 14% and the pH was 7. After 5 months, the degradable composite polypropylene non-woven fabrics were taken out and weighed respectively as the weight after biodegradation. Then, the weight loss rate after biodegradation was calculated. The calculation formula and calculation results are as follows:

[0143] Weight loss rate after biodegradation = (200-weight after biodegradation) / 200×100%

[0144]

[0145] Test Example 7

[0146] 200 g of each of the degradable composite polypropylene non-woven fabrics prepared in Examples 1-3 and Comparative Examples 1-2 were taken and buried in soil at a depth of 15 cm from the surface. The soil moisture content was 20% and the pH was 8. After 5 months, the degradable composite polypropylene non-woven fabrics were taken out and weighed respectively as the weight after biodegradation. The weight loss rate after biodegradation was then calculated. The calculation formula and the calculation results are as follows:

[0147] Weight loss rate after biodegradation = (200-weight after biodegradation) / 200×100%

[0148]

[0149] It can be seen from the above results that by adding degradation masterbatch, the influence of soil conditions on the degradability of the degradable composite polypropylene non-woven fabric can be reduced.

[0150] Unless otherwise specified, all percentages used in the present invention are by mass.

[0151] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a degradable composite polypropylene non-woven fabric, characterized in that: include: Preparation of degradation masterbatch, preparation of reinforcement masterbatch, preparation of s-layer spinning, preparation of m-layer spinning, hot rolling, post-treatment; The method for preparing the degradation masterbatch comprises adding an ethanol solution of zinc acetate and an ethanol solution of sodium hydroxide into a reactor, controlling the temperature of the reactor to 2-5° C., stirring, slowly dropping an ethanol solution of magnesium acetate, and controlling the temperature of the reactor to 30-35° C. after the dropping is completed, continuing to stir, adding a modification liquid, continuing to stir, adding n-hexane, continuing to stir, centrifuging, and drying the precipitate after the centrifugation to obtain modified quantum dots; adding polylactic acid, modified quantum dots, and polyethylene wax into a twin-screw extruder for melt extrusion, and pelletizing after the melt extrusion is completed to obtain the degradation masterbatch; The modified liquid comprises, by weight, 5-6 parts of γ-aminopropyltriethoxysilane, 2-3 parts of sodium alginate, 1-1.5 parts of polyethylene glycol diacrylate, and 100-105 parts of deionized water; The post-treatment comprises spraying the surface treatment liquid uniformly on the surface of the primary degradable composite polypropylene non-woven fabric, and controlling the amount of the surface treatment liquid to be 20-25 g / m 2 After spraying, it is placed in a drying condition at 70-75°C to obtain a degradable composite polypropylene non-woven fabric; In the post-treatment, the surface treatment liquid comprises, by weight, 2-3 parts of chitosan oligosaccharide, 3-4 parts of water-soluble nano titanium dioxide, and 100-110 parts of deionized water.

2. The method for preparing the degradable composite polypropylene nonwoven fabric according to claim 1, characterized in that: In the preparation of the degradation masterbatch, the weight ratio of the zinc acetate ethanol solution, the sodium hydroxide ethanol solution, the magnesium acetate ethanol solution, the modification liquid, and n-hexane is 30-40:15-20:10-15:40-50:140-160; The weight ratio of polylactic acid, modified quantum dots and polyethylene wax is 90-95:8-10:2-3.

3. The method for preparing the degradable composite polypropylene nonwoven fabric according to claim 1, characterized in that: In the preparation of the degradation masterbatch, the mass fraction of the zinc acetate ethanol solution is 2-2.5%; The mass fraction of the sodium hydroxide ethanol solution is 2-2.5%; The mass fraction of the magnesium acetate ethanol solution is 0.8-1%, and the dropping speed is 10-12 g / min; The weight average molecular weight of the polylactic acid is 80,000-150,000.

4. The method for preparing the degradable composite polypropylene nonwoven fabric according to claim 1, characterized in that: In the preparation of the reinforced masterbatch, polylactic acid, light calcium carbonate, kaolin, γ-aminopropyl triethoxysilane and nano zinc oxide are added into a twin-screw extruder for melt extrusion, and pelletized after the melt extrusion to obtain the degradation masterbatch.

5. The method for preparing the degradable composite polypropylene non-woven fabric according to claim 1, characterized in that: In the preparation of the reinforced masterbatch, the weight ratio of polylactic acid, light calcium carbonate, kaolin, γ-aminopropyltriethoxysilane and nano zinc oxide is 70-75:5-8:5-10:0.5-1; The weight average molecular weight of the polylactic acid is 80,000-150,000; The particle size of the nano zinc oxide is 50-100nm.

6. The method for preparing the degradable composite polypropylene nonwoven fabric according to claim 1, characterized in that: The S-layer spinning is prepared by adding polypropylene, high melt index polypropylene, PE-PP block copolymer, degradation masterbatch, reinforcement masterbatch and white masterbatch into a high-speed mixer according to a weight ratio of 85-90:4-6:12-15:10-12:5-8:2-2.5, mixing them evenly, adding them into a twin-screw extruder for melt extrusion, and performing melt metering, die head spinning and drafting treatment after melt extrusion to obtain S-layer spinning; 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 high melt index polypropylene has an MFR of 800-1500 g / 10 min at 230° C. and 2.16 kg; The MFR of the PE-PP block copolymer at 230° C. and 2.16 kg is 32-40 g / 10 min; The white masterbatch comprises, by weight: 80-90 parts of polyethylene, 25-30 parts of titanium dioxide, and 3-5 parts of polyethylene wax; The polyethylene has an MFR of 1 to 2 g / 10 min at 230° C. and 2.16 kg.

7. The method for preparing the degradable composite polypropylene nonwoven fabric according to claim 1, characterized in that: The m-layer spinning is prepared by adding high melt index polypropylene and degradation masterbatch in a weight ratio of 90-95:10-15 into a high-speed mixer and mixing them evenly, adding them into a twin-screw extruder for melt extrusion, and performing melt metering, die head spinning and drafting after melt extrusion to obtain m-layer spinning; In the preparation of the m-layer spinning, the MFR of the high melt index polypropylene at 230° C. and 2.16 kg is 800-1500 g / 10 min.

8. The method for preparing the degradable composite polypropylene nonwoven fabric according to claim 1, characterized in that: The hot rolling is used to separate the s-layer spinning and the m-layer spinning into a web, which are s-layer, m-layer, m-layer and s-layer from top to bottom. After the web laying, hot rolling treatment and humidification treatment are carried out at the same time. After the hot rolling, a primary degradable composite polypropylene non-woven fabric is obtained.

9. The method for preparing the degradable composite polypropylene nonwoven fabric according to claim 1, characterized in that: The preparation method of the water-soluble nano titanium dioxide is as follows: nano titanium dioxide, acrylamide and acetone are added into a closed reactor, the closed reactor is evacuated and nitrogen is introduced until the gas pressure is 0.2-0.25 MPa, the temperature of the closed reactor is controlled to 40-45° C., the mixture is poured out after stirring, ultraviolet light is irradiated, and then centrifuged, and after the centrifugation, the precipitate is placed at 70-80° C. for drying to obtain the water-soluble nano titanium dioxide.

10. The method for preparing the degradable composite polypropylene nonwoven fabric according to claim 1, characterized in that: In the preparation of the water-soluble nano titanium dioxide, the wavelength of ultraviolet light irradiation is 320-380nm, the temperature is 40-45°C, and the time is 40-45min; The particle size of the nano titanium dioxide is 10-50nm.

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