A polypropylene SMS nonwoven fabric and its preparation method

Abstract

This application relates to the field of nonwoven fabric technology, and in particular to a polypropylene SMS nonwoven fabric and its preparation method. The method for preparing a high-barrier polypropylene SMS nonwoven fabric involves using PP spunbond and PP meltblown materials to prepare an SMS nonwoven fabric prefabricated fabric, followed by impregnation with a solution, drying, and cooling to achieve the desired high-barrier polypropylene SMS nonwoven fabric. The impregnation solution for the high-barrier polypropylene SMS nonwoven fabric uses a combination of vinyl-terminated silicone oil, hydrogen-terminated silicone oil, a crosslinking agent, castor oil, and acrylic monomers. The film formed by the reaction of the vinyl-terminated silicone oil, hydrogen-terminated silicone oil, crosslinking agent, castor oil, and acrylic monomers exhibits high density, uniformity, and low surface energy, resulting in a high-barrier polypropylene SMS nonwoven fabric with excellent resistance to alcohol, water, and oil, as well as anti-slip properties.

Description

Technical Field

[0001] This application relates to the field of nonwoven fabric technology, and in particular to a polypropylene SMS nonwoven fabric and its preparation method. Background Technology

[0002] With the continuous improvement of medical standards, hospitals are paying increasing attention to the prevention and control of infection risks during surgery, and medical drapes are being widely used. Surgical drapes act as a barrier against bacteria and fluids, reducing contamination of patients, medical staff, and the environment during the procedure.

[0003] Currently, in medical surgeries with large fluid output, most medical drapes are made of PE plastic film and impregnated cloth composite material or composite spunbond nonwoven fabric. The anti-leakage effect is not good, and body fluids can easily seep in during use, causing bed contamination. Moreover, the PE film surface of the drape is relatively slippery between the drape and the bed, making it easy to shift. Summary of the Invention

[0004] To address the poor barrier properties of existing medical drapes using nonwoven fabrics, this application provides a high-barrier polypropylene SMS nonwoven fabric and its preparation method.

[0005] In one aspect, this application provides a method for preparing a high-barrier polypropylene SMS nonwoven fabric.

[0006] A method for preparing high-barrier polypropylene SMS nonwoven fabric, the raw materials used include 60-75 parts of PP spunbond material and 25-38 parts of PP meltblown material.

[0007] The raw materials are melt-extruded, fiber-stretched into a web and hot-rolled for reinforcement to obtain SMS nonwoven fabric; the SMS nonwoven fabric is then treated with impregnation solution, dried and cooled for shaping to obtain high-barrier polypropylene SMS nonwoven fabric.

[0008] The impregnation solution includes component A and component B, wherein component A comprises the following components in parts by weight:

[0009] Vinyl-terminated silicone oil: 30-50 parts;

[0010] Hydrogen-containing silicone oil: 10-15 parts;

[0011] Crosslinking agent: 2-5 parts;

[0012] Emulsifier: 20-35 parts;

[0013] Organic acids: 1-2 parts;

[0014] Acrylic monomers: 10-15 parts; castor oil: 2-5 parts;

[0015] 100 parts water;

[0016] Component B comprises at least the following components in parts by weight:

[0017] Vinyl silicone oil: 10-20 parts;

[0018] Platinum catalyst: 0.1-1 part.

[0019] By adopting the above technical solution, after the vinyl silicone oil, hydrogen-containing silicone oil, crosslinking agent and acrylic monomer in the impregnation solution are attached to the SMS nonwoven fabric, a film layer with a network structure is formed in the SMS nonwoven fabric during the drying process. This film layer has low surface energy and excellent barrier properties against alcohol, water and oil.

[0020] The polymer formed by the polymerization of acrylic monomers in the impregnation solution has good film-forming and adhesion properties, which improves the density of the formed film layer and thus enhances the barrier properties of high-barrier polypropylene SMS nonwoven fabric against alcohol, water and oil.

[0021] The impregnation solution uses a crosslinking agent and castor oil in combination to improve the crosslinking degree of the formed film layer, and at the same time improve the dispersion performance between the terminal vinyl silicone oil, the terminal hydrogen silicone oil and the acrylic monomers, thereby improving the uniformity and strength of the formed film layer. This results in the high-barrier polypropylene SMS nonwoven fabric having excellent barrier properties against alcohol, water and oil.

[0022] Preferably, component A further includes 4-6 parts by weight of modified calcium carbonate and 3-5 parts by weight of nitrile rubber; the modified calcium carbonate is prepared by modifying calcium carbonate with vinyltriethoxysilane.

[0023] By adopting the above technical solutions, the polymers formed by modified calcium carbonate and terminal vinyl silicone oil and terminal hydrogen-containing silicone oil have good affinity, and the polymers formed by nitrile rubber and acrylic monomers have good affinity. The use of modified calcium carbonate and nitrile rubber in combination results in a more uniform dispersion of modified calcium carbonate and nitrile rubber particles in the formed film, which enhances the strength and toughness, while forming a certain roughness on the surface of the film, thereby improving the anti-slip performance of the formed film.

[0024] Preferably, the calcium carbonate has a particle size of 15-25 μm and the nitrile rubber has a particle size of 20-45 μm;

[0025] In the preparation of the modified calcium carbonate, the mass ratio of calcium carbonate to vinyltriethoxysilane is 1:(5-9).

[0026] By adopting the above technical solution, and by optimizing the particle size of calcium carbonate and nitrile rubber and the mass ratio of calcium carbonate to vinyltriethoxysilane, the anti-slip performance of the formed film is further improved.

[0027] Preferably, the acrylic monomer is a composition of hard acrylic monomer and soft acrylic monomer in a mass ratio of 1:(2-3).

[0028] By adopting the above technical solution, and by selecting the optimal hard acrylic monomers and soft acrylic monomers, as well as the optimal weight of the hard acrylic monomers and soft acrylic monomers, the uniformity, strength, and hardness of the formed film layer are further improved.

[0029] Preferably, the hard acrylic monomer is methyl methacrylate or styrene; the soft acrylic monomer is one of hexadecyl methacrylate, dodecyl methacrylate, dodecamethacrylate, ethyl acrylate, and n-octyl methacrylate.

[0030] By adopting the above technical solution and optimizing the types of hard and soft acrylic monomers, the uniformity, strength, and hardness of the formed film are further improved, thereby enhancing the barrier properties and anti-slip properties of high-barrier polypropylene SMS nonwoven fabric against alcohol, water, and oil.

[0031] Preferably, the impregnation solution for the high-barrier polypropylene SMS nonwoven fabric further includes 0.8-2.0 parts of spunbond-specific blue masterbatch and 0.8-2.0 parts of meltblown-specific blue masterbatch.

[0032] By adopting the above technical solution, spunbond-specific blue masterbatch and meltblown-specific blue masterbatch are added to the raw materials of the impregnation solution of high-barrier polypropylene SMS nonwoven fabric, changing the color of the nonwoven fabric, making the polypropylene SMS nonwoven fabric more beautiful and easier to identify, and suitable for more application scenarios.

[0033] Preferably, the crosslinking agent is vinyltrimethoxysilane or vinyltriethoxysilane; the catalyst is organotin DBTDL or chelated tin catalyst U303.

[0034] By adopting the above technical solution, the preferred crosslinking agent is vinyltrimethoxysilane or vinyltriethoxysilane, which increases the crosslinking density of the raw materials forming the film layer in the impregnation solution of high-barrier polypropylene SMS nonwoven fabric; through catalyst catalysis, the reaction rate between the raw materials in the impregnation solution of high-barrier polypropylene SMS nonwoven fabric is increased, forming a network structure film layer with higher strength, thereby improving the barrier properties and anti-slip properties of high-barrier polypropylene SMS nonwoven fabric against alcohol, water and oil.

[0035] Preferably, the emulsifier is a nonionic emulsifier; the organic acid is one of phytic acid, oxalic acid and citric acid.

[0036] By adopting the above technical solution, an emulsifier is used to disperse the raw materials of the impregnation liquid of the high-barrier polypropylene SMS nonwoven fabric into relatively stable latex particles. The combination of organic acid and emulsifier gives the latex particles a small charge, which improves the stability between the latex particles and allows the impregnation liquid to adhere more evenly to the high-barrier polypropylene SMS nonwoven fabric, thereby improving the barrier properties of the high-barrier polypropylene SMS nonwoven fabric against alcohol, water and oil.

[0037] Preferably, the residual rate of the impregnation solution in the finishing process is 80-90%, the temperature of the impregnation solution is 30-40℃, the drying temperature is 110-125℃, and the drying time is 2-5 min.

[0038] By adopting the above technical solution, the impregnation liquid is impregnated and adhered to the SMS nonwoven fabric, and then reacts during drying to form a film layer with anti-alcohol, water-repellent, oil-repellent and anti-slip properties.

[0039] On the other hand, this application provides a high-barrier polypropylene SMS nonwoven fabric prepared by the preparation method of the high-barrier polypropylene SMS nonwoven fabric of this application.

[0040] A high-barrier polypropylene SMS nonwoven fabric is prepared by impregnating SMS nonwoven fabric with an impregnation solution and then drying it. The ratio of component A to component B in the impregnation solution is 1:(1-1.3).

[0041] By adopting the above technical solution and optimizing the dosage of components A and B, the impregnation solution has a suitable reaction rate to match the preparation process. At the same time, the impregnation solution forms a film layer on the polypropylene SMS nonwoven fabric with excellent resistance to alcohol, water, oil and slip.

[0042] In summary, this application has the following beneficial effects:

[0043] 1. In the impregnation solution of high-barrier polypropylene SMS nonwoven fabric, terminal vinyl silicone oil, terminal hydrogen silicone oil, crosslinking agent and acrylic monomers are used in combination to form a film layer. The film layer formed by terminal vinyl silicone oil, terminal hydrogen silicone oil, crosslinking agent and acrylic monomers has good density and low surface energy. Further use of crosslinking agent and castor oil improves the crosslinking degree and uniformity of the reaction film layer, so that the prepared high-barrier polypropylene SMS nonwoven fabric has excellent barrier properties against alcohol, water and oil.

[0044] 2. Modified calcium carbonate and nitrile rubber are used together in the impregnation solution of high-barrier polypropylene SMS nonwoven fabric to form uniformly dispersed anti-slip particles in the film layer, thereby enhancing the strength and toughness of the film layer and improving its anti-slip performance.

[0045] 3. By using a combination of hard and soft acrylic monomers in the impregnation solution and optimizing the types of hard and soft acrylic monomers, the compatibility between the polymers formed by the reaction of acrylic monomers and the polymers formed by the reaction of terminal vinyl silicone oil and terminal hydrogen-containing silicone oil is improved, resulting in a more uniform film layer and improved film hardness. This addresses the problem of low hardness in films containing more siloxane groups and poor compatibility with modified calcium carbonate and nitrile rubber, thereby improving the barrier properties and anti-slip properties of high-barrier polypropylene SMS nonwoven fabric against alcohol, water, and oil. Detailed Implementation

[0046] raw material

[0047] PP spunbond material (MFR range 35±2g / 10min), PP meltblown material (MFR range 1300±200g / 10min), spunbond-specific blue masterbatch (MFR range 20±2g / 10min), meltblown-specific blue masterbatch (MFR range 120±20g / 10min), vinyl silicone oil (2.38g viscosity 10000cs, vinyl content 0.06mmol / g), hydrogen-terminated silicone oil (2.08g viscosity 40cs, hydrogen content 0.7mmol / g), castor oil (iodine value: 82-90gI / 100g, hydroxyl value: 160-168mgKOH / g).

[0048] Preparation example of intermediate

[0049] Preparation Example 1-1, a modified calcium carbonate

[0050] 9 g of vinyltriethoxysilane was added to a 5 L aqueous solution with pH 3 and stirred for 10 min. Then, 1 kg of calcium carbonate with a particle size of 15 μm was added for surface modification. The mixture was filtered and washed with water until neutral to obtain modified calcium carbonate.

[0051] Preparation Examples 1-2: A Modified Calcium Carbonate

[0052] 7 g of vinyltriethoxysilane was added to a 5 L aqueous solution with pH 5 and stirred for 10 min. Then, 1 kg of calcium carbonate with a particle size of 20 μm was added for surface modification. The mixture was filtered and washed with water until neutral to obtain modified calcium carbonate.

[0053] Preparation Examples 1-3: A Modified Calcium Carbonate

[0054] Add 5g of vinyltriethoxysilane to a 5L aqueous solution with pH 4, stir for 5min, then add 1kg of calcium carbonate with a particle size of 25μm for surface modification, filter and wash with water until neutral to obtain modified calcium carbonate.

[0055] Preparation Examples 1-4, a modified calcium carbonate, differ from Preparation Example 1-1 in that it uses 10 μm calcium carbonate and 3 g of vinyltriethoxysilane.

[0056] Preparation Examples 1-5, a modified calcium carbonate, differ from Preparation Example 1-1 in that it uses 30 μm calcium carbonate and 12 g of vinyltriethoxysilane.

[0057] Preparation Example 2-1: An impregnation solution was prepared using the types and weights of the raw materials shown in Table 1, and was prepared according to the following method: Group A: Vinyl-terminated silicone oil, hydrogen-terminated silicone oil, crosslinking agent, emulsifier, organic acid, acrylic monomer, castor oil and water were mixed evenly to obtain the solution.

[0058] Group B formulation: Vinyl silicone oil and platinum catalyst are mixed evenly to obtain the product.

[0059] Preparation Examples 2-2 to 2-4 are impregnation solutions that differ from Preparation Example 2-1 in that the types and weights of the raw materials used are different, as detailed in Table 1.

[0060] Table 1 lists the types and weights of raw materials used in the impregnation solutions of Preparation Examples 2-1 to 2-4.

[0061]

[0062]

[0063] Preparation Example 2-5, an impregnation solution, differs from Preparation Example 2-1 in that the acrylic monomers used are a combination of methyl methacrylate and n-octyl methacrylate in a mass ratio of 1:1.

[0064] Preparation Example 2-6, an impregnation solution, differs from Preparation Example 2-1 in that the acrylic monomers used are a combination of methyl methacrylate and n-octyl methacrylate in a mass ratio of 1:2.

[0065] Preparation Example 2-7, an impregnation solution, differs from Preparation Example 2-1 in that the acrylic monomers used are a composition of methyl methacrylate and dodecyl 2-methacrylate in a mass ratio of 1:3.

[0066] Preparation Example 2-8, an impregnation solution, differs from Preparation Example 2-1 in that the acrylic monomers used are a composition of styrene and n-octyl methacrylate in a mass ratio of 1:4.

[0067] Preparation Examples 2-9, an impregnation liquid, differ from Preparation Example 2-1 in that the acrylic monomers used are a composition of methyl methacrylate and hexadecyl methacrylate in a mass ratio of 1:3; the modified calcium carbonate of Preparation Examples 1-4 is used; and nitrile rubber with a particle size of 15 μm is used.

[0068] Preparation Example 2-10, an impregnation liquid, differs from Preparation Example 2-1 in that the acrylic monomers used are a composition of styrene and methacrylate dodecyl ester in a mass ratio of 1:4; the modified calcium carbonate of Preparation Example 1-5 is used; and nitrile rubber with a particle size of 50 μm is used.

[0069] Preparation Example 2-11, an impregnation liquid, differs from Preparation Example 2-1 in that the acrylic monomer used is methyl methacrylate; the modified calcium carbonate of Preparation Example 1-4 is used; and nitrile rubber with a particle size of 15 μm is used.

[0070] Preparation Example 2-12, an impregnation liquid, differs from Preparation Example 2-1 in that the acrylic monomer used is ethyl acrylate; the modified calcium carbonate of Preparation Example 1-5 is used; and nitrile rubber with a particle size of 50 μm is used.

[0071] Preparation Example 2-13, an impregnation solution, differs from Preparation Example 2-1 in that the modified calcium carbonate used is the same as that used in Preparation Example 1-3, and the modified calcium carbonate used is nitrile rubber with a particle size of 45 μm.

[0072] Preparation Example 2-14, an impregnation solution, differs from Preparation Example 2-1 in that it uses an equal amount of calcium carbonate with a particle size of 15 μm to replace the modified calcium carbonate, and does not use nitrile rubber.

[0073] Preparation Example 2-15, an impregnation solution, differs from Preparation Example 2-1 in that it uses the modified calcium carbonate of Preparation Example 1-4 and nitrile rubber with a particle size of 15 μm.

[0074] Preparation Example 2-16, an impregnation solution, differs from Preparation Example 2-1 in that it uses the modified calcium carbonate of Preparation Example 1-5 and nitrile rubber with a particle size of 50 μm.

[0075] Preparation Example 2-17, an impregnation liquid, differs from Preparation Example 2-1 in that it does not use nitrile rubber.

[0076] Preparation Example 2-18, an impregnation solution, differs from Preparation Example 2-1 in that it does not use modified calcium carbonate.

[0077] Preparation Example 2-19, an impregnation solution, differs from Preparation Example 2-1 in that it does not use modified calcium carbonate and nitrile rubber.

[0078] Example

[0079] Example 1: A method for preparing a high-barrier polypropylene SMS nonwoven fabric, using the raw materials listed in Table 2, and following the preparation steps:

[0080] 1) Raw material melt extrusion

[0081] The blue masterbatch for spunbond and the blue masterbatch for meltblown are transported to the main screw by compressed air through the auxiliary material tank. The blue masterbatch for spunbond and PP spunbond, and the blue masterbatch for meltblown and PP meltblown are mixed evenly under the shear force of the screw to obtain spunbond mixture and meltblown mixture.

[0082] The spunbond and meltblown blends were melted separately and then extruded quantitatively using a metering pump. The melting temperature of the spunbond blend was 230±5℃, and the melting temperature of the meltblown blend was 230±5℃.

[0083] 2) Fibers are drawn into a web

[0084] A high-speed airflow is used to stably draw the melt to obtain fine denier fibers. The drawing process for spunbond fiber forming is as follows: cold air chamber pressure 2500±200 Pa, cold air temperature 20±4℃; the drawing process for meltblown fiber forming is as follows: hot air volume 4000±200 m³ / h. 3 / hr, hot air temperature 250±5℃. This yields spunbond fibers with a fineness of 1.5±0.2 denier and meltblown fibers with a fineness of 2±0.5μm. The finer spunbond fibers possess excellent tensile strength, elongation, and mechanical properties, serving as the outer layer (S layer). The finer meltblown fibers possess excellent barrier properties, enhancing the water resistance of the SMS material, and serve as the core layer (M layer). The spunbond and meltblown fibers are sequentially and evenly laid on a mesh belt to form a multi-layered SMS fiber web (area density approximately 42 g / m²).

[0085] 3) Hot rolling reinforcement

[0086] The hot rolling reinforcement process uses a patterned roll temperature of 145±5℃, a smooth roll temperature of 150±5℃, and a rolling mill pressure of 87±3daN / cm. The SMS multilayer fiber web is prepared into an SMS nonwoven fabric under the action of temperature and pressure during hot rolling reinforcement.

[0087] 4) Finishing with impregnation solution

[0088] The SMS nonwoven fabric is unwound and then smoothly immersed in an impregnation bath under a certain tension using guide rollers. The temperature of the impregnation bath is 30°C. Through impregnation, the SMS nonwoven fabric is evenly wetted by the impregnation solution. Excess impregnation solution is then removed by a pair of rollers (residual impregnation rate of 90%), with a roller pressure of 65±5 psi.

[0089] 5) Drying

[0090] The SMS nonwoven fabric, after being impregnated with the impregnation solution, is dried in an oven by hot air to prepare high-barrier polypropylene SMS nonwoven fabric. The hot air temperature in the drying process is 110℃, the hot air velocity is 35±5m / s, and the drying time is 5min.

[0091] 6) Cooling and shaping

[0092] After being dried in an oven, the high-barrier polypropylene SMS nonwoven fabric is cooled, shaped, and wound into shape using a cooling device. The cold air temperature is 23±2℃, and the high-barrier polypropylene SMS nonwoven fabric exiting the oven is cooled and shaped by the cold air.

[0093] Examples 2 and 3 describe a method for preparing high-barrier polypropylene SMS nonwoven fabric. The difference between these two methods and Example 1 lies in the different weights and types of raw materials used and the different settings of the preparation process parameters, as detailed in Table 2.

[0094] Table 2 lists the types and weights of raw materials and the settings of preparation process parameters used in the preparation methods of high-barrier polypropylene SMS nonwoven fabrics of Examples 1-3.

[0095] distinguish Example 1 Example 2 Example 3 PP spunbond material / kg 60 70 75 PP meltblown material / kg 25 30 38 Spunbond blue masterbatch / kg 0.8 1.5 2 Blue masterbatch for meltblown fabric / kg 2.0 1.5 0.8 The ratio of component A to component B 1:1 1:1.2 1:1.3 Impregnation solution Preparation Example 2-1 Preparation Example 2-2 Preparation Examples 2-3 Rolling yield / % 90 85 80 Temperature of the impregnation solution / °C 30 35 40 Drying temperature / ℃ 110 120 125 Drying time / min 5 3 2

[0096] Examples 4 to 19 describe a method for preparing a high-barrier polypropylene SMS nonwoven fabric, which differs from Example 1 in that the impregnation solution is the same as that used in Examples 2-4 to 2-19.

[0097] Example 20, a method for preparing high-barrier polypropylene SMS nonwoven fabric, differs from Example 19 in that it does not use adhesive-specific blue masterbatch or meltblown-specific blue masterbatch.

[0098] Comparative Example

[0099] Comparative Example 1, a method for preparing a high-barrier polypropylene SMS nonwoven fabric, differs from Example 20 in that it does not use acrylic monomers and castor oil.

[0100] Comparative Example 2, a method for preparing a high-barrier polypropylene SMS nonwoven fabric, differs from Example 20 in that 20 kg of acrylic monomers and ethylene glycol diacrylate are used to replace castor oil in equal amounts.

[0101] Comparative Example 3, a method for preparing a high-barrier polypropylene SMS nonwoven fabric, differs from Example 20 in that it does not use a crosslinking agent or castor oil.

[0102] Comparative Example 4, a method for preparing a high-barrier polypropylene SMS nonwoven fabric, differs from Example 20 in that the terminal hydrogen-containing silicone oil in component A is replaced by an equal amount of terminal vinyl silicone oil, and no crosslinking agent is used.

[0103] Performance testing

[0104] Test 1: Oil repellency

[0105] The tests were conducted according to GB / T 19977-2005 "Textiles - Oil Repellency and Hydrocarbon Resistance Test". There are 8 levels of oil repellency, with level 8 being the highest.

[0106] Test 2: Water Repellency

[0107] The test was conducted according to GB / T4745-2012 "Test and Evaluation of Water Repellency of Textiles - Water Repellency Method". There are five water repellency levels. Level 5 is the highest, at which point the surface of the textile exposed to water is not wetted and no water droplets remain on the surface.

[0108] Test 3: Alcohol Resistance

[0109] The test was conducted using WSP 80.6, "Standard Test Method for Ethanol Resistance of Nonwoven Fabrics," with a total of 10 levels.

[0110] Washing process: The test sample was placed in a washing machine (Haier EB80MO09 8KG), the water volume was set to 18L, laundry detergent (Diaopai antibacterial phosphate-free laundry detergent) was added, with 3g of laundry detergent per liter of water, the washing temperature was set to 60℃, the washing time was 40min, and the number of washes was 10.

[0111] Experiment 4: Coefficient of Friction

[0112] The test was conducted according to ASTM D1894-01, "Test methods for static and dynamic coefficients of friction of plastic films and sheets".

[0113] Test samples: The high-barrier polypropylene SMS nonwoven fabrics prepared in Examples 1-20 were used as example samples; the high-barrier polypropylene SMS nonwoven fabrics prepared in Comparative Examples 1-4 were used as comparative example samples.

[0114] Test results: The test results of water repellency, oil repellency, alcohol repellency and friction coefficient of the high-barrier polypropylene SMS nonwoven fabrics prepared in Examples 1-20 and Comparative Examples 1-4 are shown in Table 3.

[0115] Table 3 lists the experimental results of water repellency, oil repellency, alcohol repellency, and coefficient of friction of the high-barrier polypropylene SMS nonwoven fabrics prepared in Examples 1-20 and Comparative Examples 1-4.

[0116]

[0117]

[0118] Combining Examples 1-20 and Comparative Examples 1-4 with Table 3, it can be seen that:

[0119] The high-barrier polypropylene SMS nonwoven fabrics prepared in Examples 1-20 exhibit higher water repellency, oil repellency, alcohol repellency, and coefficient of friction than those in Comparative Examples 1-4. This may be because the impregnation solution for the high-barrier polypropylene SMS nonwoven fabric uses a combination of vinyl-terminated silicone oil, hydrogen-terminated silicone oil, crosslinking agent, and acrylic monomers to form a film. The film formed by the vinyl-terminated silicone oil, hydrogen-terminated silicone oil, crosslinking agent, and acrylic monomers has better density and lower surface energy. Furthermore, the use of a crosslinking agent and castor oil enhances the crosslinking degree and uniformity of the film formed by the reaction, resulting in high-barrier polypropylene SMS nonwoven fabrics with excellent alcohol, water, and oil repellency properties.

[0120] In Comparative Example 2, when the content of acrylic monomers in the impregnation solution increases, the content of siloxanes in the resulting coating decreases relatively, which may lead to an increase in the surface energy of the coating formed by the impregnation solution. Replacing castor oil with an equal amount of ethylene glycol diacrylate has two drawbacks. First, ethylene glycol diacrylate has fewer carbon-carbon double bond functional groups than castor oil, resulting in a decrease in the degree of cross-linking of the film. Second, the molecular structure of ethylene glycol diacrylate lacks the long alkyl molecular chains containing ether bonds and hydroxyl groups found in the molecular structure of castor oil. Therefore, it is less effective than castor oil in promoting the compatibility and dispersion of acrylic monomers, terminal vinyl silicone oil, and terminal hydrogen-containing silicone oil in the impregnation solution, leading to a decrease in the uniformity of the film formed by the impregnation solution. This results in a decrease in the water repellency, oil repellency, alcohol repellency, and coefficient of friction of the high-barrier polypropylene SMS nonwoven fabric.

[0121] The high-barrier polypropylene SMS nonwoven fabrics prepared in Examples 1-10 exhibited higher water repellency, oil repellency, alcohol repellency, and coefficient of friction after washing compared to Examples 11-12. This indicates that using a combination of hard and soft acrylate monomers in the acrylic monomers is beneficial for improving the water repellency, oil repellency, alcohol repellency, and coefficient of friction of the high-barrier polypropylene SMS nonwoven fabrics. This may be because using soft acrylate monomers improves the compatibility between the acrylic acid polymer and the siloxane polymer formed in the reaction, thereby improving the uniformity and density of the formed film, and thus enhancing the water repellency, oil repellency, and alcohol repellency of the high-barrier polypropylene SMS nonwoven fabrics. Using hard acrylate monomers in the acrylic monomers is beneficial for improving the strength, hardness, and abrasion resistance of the formed film. Furthermore, when used in combination with reinforced modified calcium carbonate and nitrile rubber, it further enhances the coefficient of friction and anti-slip properties of the film.

[0122] The high-barrier polypropylene SMS nonwoven fabrics prepared in Examples 6-7 exhibited higher water repellency, oil repellency, alcohol repellency, and coefficient of friction than those in Examples 1, 5, and 8-10. This indicates that the acrylate hard monomer used was methyl methacrylate, and the acrylate soft monomer used was either n-octyl methacrylate or dodecyl 2-methacrylate. Furthermore, when the mass ratio of the acrylate hard monomer to the acrylate soft monomer was 1:(2-3), the particle size of calcium carbonate was 15-25 μm, and the particle size of nitrile rubber was 20-45 μm, the water repellency, oil repellency, and coefficient of friction of the prepared high-barrier polypropylene SMS nonwoven fabric were further improved. The grade and coefficient of friction may be affected because when the acrylate soft monomer is n-octyl methacrylate or dodecyl 2-methacrylate, the branched chains on the acrylic monomer make the formed film layer denser, thereby improving the water repellency, oil repellency, and alcohol repellency of the high-barrier polypropylene SMS nonwoven fabric. When the branched chains of the acrylic monomer are too long, it is not conducive to the reaction between vinyl groups and terminal vinyl silicone oil and / or terminal hydrogen silicone oil, resulting in a reduction in the crosslinking points between the polymer formed by the acrylic monomer and the polymer formed by terminal vinyl silicone oil and / or terminal hydrogen silicone oil, causing a decrease in the water repellency, oil repellency, and alcohol repellency of the high-barrier polypropylene SMS nonwoven fabric.

[0123] When styrene is used as the hard monomer for acrylic acid, the presence of large molecular phenyl groups on styrene may hinder the addition reaction with end-vinyl silicone oil and / or end-hydrogen silicone oil. This can lead to poor compatibility between the polymer formed by the acrylic monomer and the polymer formed by end-vinyl silicone oil and / or end-hydrogen silicone oil, resulting in a decrease in the crosslinking degree of the film layer and a decrease in the water repellency, oil repellency, and alcohol repellency of the high-barrier polypropylene SMS nonwoven fabric.

[0124] When the particle size of calcium carbonate and nitrile rubber is too small, the roughness of the film layer is insufficient; when the particle size of calcium carbonate and nitrile rubber is too large, the number of calcium carbonate and nitrile rubber particles decreases under a certain weight, and the roughness of the film layer decreases.

[0125] When the mass ratio of hard acrylate monomers to soft acrylate monomers is greater than 1:(2-3), the compatibility between the polymer formed by the acrylic monomers and the polymer formed by the siloxane is poor, resulting in a decrease in the uniformity of the film layer formed by the impregnation liquid, which in turn causes a decrease in the water repellency, oil repellency, alcohol repellency, and coefficient of friction of the high-barrier polypropylene SMS nonwoven fabric. When the mass ratio of hard acrylate monomers to soft acrylate monomers is less than 1:(2-3), the strength and hardness of the film layer formed by the impregnation liquid are poor, and the synergistic effect between the film layer and the modified calcium carbonate and nitrile rubber is poor, which in turn causes a decrease in the water repellency, oil repellency, alcohol repellency, and coefficient of friction of the high-barrier polypropylene SMS nonwoven fabric after washing.

[0126] The high-barrier polypropylene SMS nonwoven fabrics prepared in Examples 1 and 13, after being washed 20 times, exhibited higher water repellency, oil repellency, alcohol repellency, and coefficient of friction than those in Examples 14 to 19. This indicates that the use of modified calcium carbonate and nitrile rubber, along with the optimal particle size of the calcium carbonate and nitrile rubber, further improved the water repellency, oil repellency, alcohol repellency, and coefficient of friction of the high-barrier polypropylene SMS nonwoven fabric.

[0127] The use of modified calcium carbonate and nitrile rubber may improve the density and strength of the film formed by the impregnation solution. Nitrile rubber is more easily dispersed in acrylic polymers, while modified calcium carbonate is more easily dispersed in polymers formed by siloxanes. The use of modified calcium carbonate and nitrile rubber results in a more uniform roughness in the film formed by the impregnation solution, thereby improving the anti-slip properties of the high-barrier polypropylene SMS nonwoven fabric. Under quantitative conditions, the particle size of calcium carbonate and nitrile rubber is preferred to adjust the roughness, which, together with the hard acrylic monomer, enhances the hardness and strength of the film formed by the impregnation solution, further improving the water repellency, oil repellency, alcohol repellency, and coefficient of friction of the high-barrier polypropylene SMS nonwoven fabric.

[0128] The preferred mass ratio of calcium carbonate to vinyltriethoxysilane is 1:(5-9). When the mass ratio of calcium carbonate to vinyltriethoxysilane is less than 1:(5-9), too many vinyl groups may be coated on the surface of calcium carbonate, which promotes the dispersion of modified calcium carbonate in acrylic polymers and is not conducive to the dispersion of modified calcium carbonate in polymers formed by end-vinyl silicone oil and end-hydrogen-containing silicone oil, resulting in a decrease in the uniformity of anti-slip particles in the film layer formed by the impregnation liquid. When the mass ratio of calcium carbonate to vinyltriethoxysilane is greater than 1:(5-9), fewer vinyl groups are connected to the surface of modified calcium carbonate, which weakens the synergistic effect between modified calcium carbonate and acrylic polymers, resulting in a decrease in the water repellency, oil repellency, alcohol repellency and friction coefficient of high-barrier polypropylene SMS nonwoven fabric.

[0129] The vinyl groups on the surface of modified calcium carbonate can participate in the polymerization reaction of carbon-carbon double bonds. Compared with calcium carbonate, modified calcium carbonate can produce a better synergistic effect with the film layer formed by the impregnation liquid, thereby improving the water repellency, oil repellency, alcohol repellency and friction coefficient of high-barrier polypropylene SMS nonwoven fabric.

[0130] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A method for preparing a high-barrier polypropylene SMS nonwoven fabric, characterized in that, By weight, the raw materials used include 60-75 parts of PP spunbond and 25-38 parts of PP meltblown material; The raw materials are melt-extruded, fiber-stretched into a web and hot-rolled for reinforcement to prepare SMS nonwoven fabric; the SMS nonwoven fabric is then treated with impregnation solution, dried and cooled to prepare high-barrier polypropylene SMS nonwoven fabric. The impregnation solution includes component A and component B, wherein component A comprises the following components in parts by weight: Vinyl-terminated silicone oil: 30-50 parts; Hydrogen-containing silicone oil: 10-15 parts; Crosslinking agent: 2-5 parts; Emulsifier: 20-35 parts; Organic acids: 1-2 parts; Acrylic monomers: 10-15 parts; castor oil: 2-5 parts; 100 parts water; Component A further includes 4-6 parts by weight of modified calcium carbonate and 3-5 parts by weight of nitrile rubber; the modified calcium carbonate is prepared by modifying calcium carbonate with vinyltriethoxysilane; Component B comprises at least the following components in parts by weight: Vinyl silicone oil: 10-20 parts; Catalyst: 0.1-1 part; The crosslinking agent is vinyltrimethoxysilane or vinyltriethoxysilane; the catalyst is organotin DBTDL or chelated tin catalyst U303.

2. The method for preparing a high-barrier polypropylene SMS nonwoven fabric according to claim 1, characterized in that, The calcium carbonate has a particle size of 15-25 μm and the nitrile rubber has a particle size of 20-45 μm; In the preparation of the modified calcium carbonate, the mass ratio of calcium carbonate to vinyltriethoxysilane is 1:(5-9).

3. The method for preparing a high-barrier polypropylene SMS nonwoven fabric according to claim 1, characterized in that, The acrylic monomers are a composition of hard acrylic monomers and soft acrylic monomers in a mass ratio of 1:(2-3).

4. The method for preparing a high-barrier polypropylene SMS nonwoven fabric according to claim 3, characterized in that, The hard acrylic monomer is methyl methacrylate or styrene; the soft acrylic monomer is one of hexadecyl methacrylate, dodecyl methacrylate, 2-methacrylate, ethyl acrylate, and n-octyl methacrylate.

5. The method for preparing a high-barrier polypropylene SMS nonwoven fabric according to claim 1, characterized in that, The raw materials also include 0.8-2.0 parts of spunbond blue masterbatch and 0.8-2.0 parts of meltblown blue masterbatch.

6. The method for preparing a high-barrier polypropylene SMS nonwoven fabric according to claim 1, characterized in that, The emulsifier is a nonionic emulsifier; the organic acid is one of phytic acid, oxalic acid and citric acid.

7. The method for preparing a high-barrier polypropylene SMS nonwoven fabric according to claim 1, characterized in that, The finishing process involves a pickling rate of 80-90% for the impregnation solution and a temperature of 30-40°C for the impregnation solution; the drying temperature is 110-125°C and the drying time is 2-5 minutes.

8. A high-barrier polypropylene SMS nonwoven fabric prepared by the preparation method of any one of claims 1-7; wherein the ratio of component A to component B is 1:(1-1.3).

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