Preparation method of master batch for antibacterial polypropylene non-woven fabric

Abstract

The invention relates to the technical field of polypropylene, in particular to a preparation method of master batches for antibacterial polypropylene non-woven fabrics, which comprises the following steps: mixing modified polystyrene, nano-zinc oxide and an antioxidant in a mixer, and then melting, blending, extruding and granulating the materials in a twin-screw extruder to obtain the master batches for the antibacterial polypropylene non-woven fabrics; the modified polystyrene disclosed by the invention contains an alkyl chain, and the alkyl chain has good compatibility with polypropylene, so that the modified polystyrene can play a role of a toughening agent, and the tensile fracture performance of the polypropylene non-woven fabric is improved. The modified polystyrene is used as a compatilizer, so that the compatibility between the nano zinc oxide and the polypropylene resin is improved, and the tensile fracture performance of the non-woven fabric is further improved. The nano-zinc oxide has excellent antibacterial and bactericidal effects and is uniformly distributed in the non-woven fabric matrix, so that the antibacterial performance of the non-woven fabric is remarkably improved.

Description

Technical Field

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

[0002] Polypropylene non-woven fabrics have the advantages of light texture, good air permeability, non-toxicity, non-irritation, and low cost, and are widely used in sanitary protection products, packaging bags, etc. Traditional polypropylene non-woven fabrics have defects such as poor tensile fracture performance and poor hydrophilicity, and do not have good antibacterial properties, which limits the development and application of polypropylene non-woven fabrics.

[0003] Functional masterbatches such as antibacterial masterbatches, toughening masterbatches, color masterbatches, etc., as a processing aid, have important applications in the processing of non-woven fabrics, plastics, etc. Polystyrene has good mechanical strength, heat resistance and other properties, and after polystyrene is modified by a cross-linking agent, it can obtain cross-linked polystyrene rigid particles with better performance, which can be used as a toughening agent for materials such as polypropylene to improve the mechanical properties of the material. However, polystyrene has poor interfacial compatibility with polypropylene, and usually requires the addition of additional compatibilizers, such as PP / PS block copolymers, SBS terpolymers, etc.

[0004] Nano zinc oxide has excellent mechanical properties and antibacterial properties, and is cheap and easy to obtain. It is widely used in plastics, fibers and other materials. Improving the compatibility between nano zinc oxide and polymer material groups and improving its dispersibility are research difficulties. Chinese patent CN114685894B discloses a plastic masterbatch and its preparation method, application and non-woven fabric. Nano zinc oxide, chitosan and a dispersion medium are mixed, ball milled, and then mixed with polypropylene resin and extruded to prepare a plastic masterbatch, which can improve the dispersibility of nano zinc oxide, thereby enhancing the antibacterial effect of the plastic masterbatch. However, the zinc oxide plastic masterbatch does not improve the mechanical properties of the non-woven fabric. Summary of the invention

[0005] The invention solves the problem that the masterbatch for polypropylene non-woven fabric has no antibacterial property and has poor mechanical property.

[0006] The technical solution adopted by the present invention is: a method for preparing a masterbatch for antibacterial polypropylene non-woven fabric is: S1. Add deionized water, styrene, functional monomers and emulsifiers into a flask, mix well and add potassium persulfate, stir for reaction and add ethanol, centrifuge and separate, wash the precipitate with ethanol, and dry to obtain modified polystyrene.

[0007] S2. The modified polystyrene, nano zinc oxide and antioxidant are mixed in a mixer, and then the materials are melt-blended, extruded and granulated in a twin-screw extruder to obtain a masterbatch for antibacterial polypropylene non-woven fabric.

[0008] Furthermore, the functional monomer structure is shown in formula (1); Formula (1), wherein n is any integer between 8 and 11.

[0009] Furthermore, in S1, the mass of the functional monomer is 15-40% of the mass of styrene.

[0010] Furthermore, in S1, the emulsifier is Span 60, Span 80, sodium dodecyl sulfate or sodium dodecylbenzene sulfonate.

[0011] Further, in S1, the reaction is carried out at a temperature of 60-75° C. for 18-30 h.

[0012] Furthermore, the mass of the nano zinc oxide is 10-30% of the mass of the modified polystyrene.

[0013] Furthermore, the mixing temperature is 50-80°C, and the mixing time is 30-60 min; the temperature of each section in the twin-screw extruder is 180-200°C, and the screw speed is 200-400 r / min.

[0014] Further, the preparation method of the functional monomer is: (1) Tetrahydrofuran, glycidyl methacrylate and ethylenediamine-N,N'-diacetic acid are added to a flask, wherein the mass of glycidyl methacrylate is 160-190% of the mass of ethylenediamine-N,N'-diacetic acid, and the mixture is reacted at a temperature of 55-75°C for 24-36 hours. The mixture is concentrated under reduced pressure to remove low boiling points and dried to obtain intermediate A.

[0015] (2) Place the flask in an ice water bath, add dichloromethane, intermediate A, alkyl acyl chloride, and triethylamine, wherein the mass of the alkyl acyl chloride is 78-110% of the mass of intermediate A; stir and react at a temperature of 15-25°C for 12-18 hours, concentrate under reduced pressure after the reaction, wash with petroleum ether, and dry to obtain a functional monomer.

[0016] Further, the structural formula of the alkyl acyl chloride is , n is any integer between 8 and 11.

[0017] Technical effect: The present invention utilizes glycidyl methacrylate and ethylenediamine-N,N'-diacetic acid to carry out a ring-opening reaction, and then carries out a preparation reaction with an alkyl acyl chloride to obtain a functional monomer containing two olefinic groups, which can undergo a cross-linking polymerization reaction with a styrene monomer to obtain a cross-linked modified polystyrene. Further, using modified polystyrene and nano zinc oxide as the main raw materials, high-temperature mixing and melt extrusion granulation are performed to obtain a masterbatch for antibacterial polypropylene non-woven fabrics. The modified polystyrene contains alkyl chains, and the alkyl chains have good compatibility with polypropylene, thereby enhancing the interfacial compatibility between the modified polystyrene and the polypropylene resin, and the cross-linked modified polystyrene can act as a toughening agent, thereby improving the tensile fracture properties of the polypropylene non-woven fabric.

[0018] The modified polystyrene of the present invention contains carboxyl groups. During the high-temperature mixing process and the melt extrusion process, the carboxyl groups can form hydrogen bonds with the hydroxyl groups on the surface of the nano zinc oxide, and undergo esterification reactions, thereby grafting the modified polystyrene molecular chains on the surface of the nano zinc oxide. Since the modified polystyrene containing the alkyl chain has good compatibility with the polypropylene resin, the modified polystyrene is used as a compatibilizer to improve the compatibility between the nano zinc oxide and the polypropylene resin. The nano zinc oxide with excellent mechanical properties is evenly distributed in the non-woven fabric matrix, further improving the tensile fracture performance of the non-woven fabric. In addition, the nano zinc oxide has excellent antibacterial and bactericidal effects, is evenly distributed in the non-woven fabric matrix, and significantly improves the antibacterial effect of the non-woven fabric on Escherichia coli and Staphylococcus aureus. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is the reaction formula for the preparation of functional monomers. DETAILED DESCRIPTION

[0020] The present application is further described in detail below in conjunction with the examples. It is particularly noted that if no specific conditions are specified in the following examples, the experiments are carried out according to conventional conditions or the conditions recommended by the manufacturer. Unless otherwise specified, the raw materials used in the following examples can be obtained from common commercial sources.

[0021] The average particle size of the nano zinc oxide of the present invention is 40nm. The grade of the polypropylene resin is HL504FB.

[0022] Example 1 (1) Add 20 mL of tetrahydrofuran, 1.9 g of glycidyl methacrylate, and 1 g of ethylenediamine-N,N'-diacetic acid into a flask, react at 60°C for 24 h, concentrate under reduced pressure to remove low boiling points, and dry to obtain intermediate A.

[0023] (2) Place the flask in an ice water bath, add 15 mL of dichloromethane, 1.5 g of intermediate A, 1.17 g of nonanoyl chloride, and 0.72 g of triethylamine, and stir at 15 °C for 18 h. After the reaction, concentrate under reduced pressure, wash with petroleum ether, and dry to obtain a functional monomer.

[0024] (3) Add 150 mL of deionized water, 20 g of styrene, 3 g of functional monomer, and emulsifier Span 80 into a flask, mix well, add 0.3 g of potassium persulfate, react at 75 °C for 18 h, add ethanol, centrifuge, wash the precipitate with ethanol, and dry to obtain modified polystyrene.

[0025] (4) Place 30 g of modified polystyrene, 0.3 g of nano zinc oxide, and 0.2 g of antioxidant 1010 in a mixer and mix at 50 °C for 60 min. Then, place the materials in a twin-screw extruder at temperatures of 180 °C, 190 °C, 200 °C, 200 °C, 200 °C, and 195 °C in sections 1 to 6 and a screw speed of 250 r / min for melt blending, extrusion and granulation to obtain a masterbatch for antibacterial polypropylene non-woven fabric.

[0026] Example 2 (1) Add 20 mL of tetrahydrofuran, 1.8 g of glycidyl methacrylate, and 1 g of ethylenediamine-N,N'-diacetic acid into a flask, react at 55°C for 36 h, concentrate under reduced pressure to remove low boiling points, and dry to obtain intermediate A.

[0027] (2) Place the flask in an ice water bath, add 25 mL of dichloromethane, 1.5 g of intermediate A, 1.41 g of decanoyl chloride, and 0.72 g of triethylamine, and stir at 20°C for 18 h. After the reaction, concentrate under reduced pressure, wash with petroleum ether, and dry to obtain a functional monomer.

[0028] (3) Add 150 mL of deionized water, 20 g of styrene, 5 g of functional monomer, and emulsifier sodium dodecyl sulfate into a flask, mix well, add 0.36 g of potassium persulfate, react at 65 °C for 30 h, add ethanol, centrifuge, wash the precipitate with ethanol, and dry to obtain modified polystyrene.

[0029] (4) Place 30 g of modified polystyrene, 0.6 g of nano zinc oxide, and 0.2 g of antioxidant 1010 in a mixer and mix at 80°C for 30 min. Then, place the materials in a twin-screw extruder at temperatures of 180°C, 190°C, 200°C, 200°C, 200°C, and 195°C in sections 1 to 6 and a screw speed of 200 r / min, and melt-blend and extrude granulate to obtain a masterbatch for antibacterial polypropylene non-woven fabric.

[0030] Example 3 (1) Add 15 mL of tetrahydrofuran, 1.6 g of glycidyl methacrylate, and 1 g of ethylenediamine-N,N'-diacetic acid into a flask, react at 75°C for 24 h, concentrate under reduced pressure to remove low boiling points, and dry to obtain intermediate A.

[0031] (2) Place the flask in an ice water bath, add 25 mL of dichloromethane, 1.5 g of intermediate A, 1.65 g of dodecanoyl chloride, and 0.85 g of triethylamine, and stir at 25 °C for 12 h. After the reaction, concentrate under reduced pressure, wash with petroleum ether, and dry to obtain a functional monomer.

[0032] (3) Add 200 mL of deionized water, 20 g of styrene, 8 g of functional monomer, and emulsifier sodium dodecylbenzene sulfonate into a flask, mix well, add 0.42 g of potassium persulfate, react at 75 °C for 18 h, add ethanol, centrifuge, wash the precipitate with ethanol, and dry to obtain modified polystyrene.

[0033] (4) Place 30 g of modified polystyrene, 0.9 g of nano zinc oxide, and 0.2 g of antioxidant 1010 in a mixer and mix at 80°C for 40 min. Then, place the materials in a twin-screw extruder at temperatures of 180°C, 190°C, 200°C, 200°C, 200°C, and 195°C in sections 1 to 6 and a screw speed of 400 r / min, and melt-blend and extrude to obtain masterbatch for antibacterial polypropylene non-woven fabrics.

[0034] Comparative Example 1 (1) Add 150 mL of deionized water, 20 g of styrene, and emulsifier Span 80 into a flask, mix well, add 0.3 g of potassium persulfate, react at 75 °C for 18 h, add ethanol, centrifuge, wash the precipitate with ethanol, and dry to obtain polystyrene.

[0035] (2) Place 30 g of polystyrene, 0.3 g of nano zinc oxide, and 0.2 g of antioxidant 1010 in a mixer and mix at 50 °C for 60 min. Then, place the materials in a twin-screw extruder at temperatures of 180 °C, 190 °C, 200 °C, 200 °C, 200 °C, and 195 °C in sections 1 to 6 and a screw speed of 250 r / min for melt blending, extrusion, and granulation to obtain a masterbatch for antibacterial polypropylene non-woven fabric.

[0036] Comparative Example 2 (1) Intermediate A was prepared according to the method of Example 1.

[0037] (2) Add 150 mL of deionized water, 20 g of styrene, 3 g of intermediate A, and emulsifier Span 80 into a flask, mix well, add 0.3 g of potassium persulfate, react at 75 °C for 18 h, add ethanol, centrifuge, wash the precipitate with ethanol, and dry to obtain modified polystyrene.

[0038] (3) Place 30 g of modified polystyrene, 0.3 g of nano zinc oxide, and 0.2 g of antioxidant 1010 in a mixer and mix at 50 °C for 60 min. Then, place the materials in a twin-screw extruder at temperatures of 180 °C, 190 °C, 200 °C, 200 °C, 200 °C, and 195 °C in sections 1 to 6 and a screw speed of 250 r / min for melt blending, extrusion, and granulation to obtain a masterbatch for antibacterial polypropylene non-woven fabric.

[0039] Comparative Example 3 (1) Add 150 mL of deionized water, 20 g of styrene, 3 g of ethylene glycol dimethacrylate, and emulsifier Span 80 into a flask, mix well, add 0.3 g of potassium persulfate, react at 75 °C for 18 h, add ethanol, centrifuge, wash the precipitate with ethanol, and dry to obtain modified polystyrene.

[0040] (2) Place 30 g of modified polystyrene, 0.3 g of nano zinc oxide, and 0.2 g of antioxidant 1010 in a mixer and mix at 50 °C for 60 min. Then, place the materials in a twin-screw extruder at temperatures of 180 °C, 190 °C, 200 °C, 200 °C, 200 °C, and 195 °C in sections 1 to 6 and a screw speed of 250 r / min for melt blending, extrusion, and granulation to obtain a masterbatch for antibacterial polypropylene non-woven fabric.

[0041] The antibacterial polypropylene non-woven fabric masterbatch (100g) prepared in each embodiment and comparative example was mixed with 1kg polypropylene resin in a mixer, and then extruded and granulated in a twin-screw extruder. The temperature of sections 1-6 was 150°C, 160°C, 170°C, 185°C, 185°C, and 180°C, and the screw speed was 250r / min. After extrusion, granulation was performed, and finally, non-woven fabric was made through melt-blown cloth equipment through melt-blown, drawing, cooling and shaping, hot air traction, and receiving processes. The melt-blown process parameters of the melt-blown cloth equipment are that the temperature of zones 1-4 is 170°C, 210°C, 225°C, 230°C, the temperature of the die zone is 230°C, the temperature of the metering pump zone is 235°C, and the temperature of the nozzle zone is 230°C. The hot air traction temperature is 250°C. The receiving distance is 40cm.

[0042] Non-woven fabric containing antibacterial polypropylene non-woven fabric masterbatch was used as the experimental sample.

[0043] A nonwoven fabric made of polypropylene resin without adding antibacterial polypropylene nonwoven fabric masterbatch was used as a blank control sample.

[0044] The breaking properties of nonwoven fabrics were tested according to the method of FZ / T60005-1991.

[0045] The surface water contact angle of non-woven fabrics was tested according to the method of GB / T 42694-2023.

[0046] Table 1 Nonwoven fabric breaking properties and water contact angle test

[0047] The antibacterial properties of non-woven fabrics were tested according to the oscillation bottle method in the standard GB / T 20944.3-2008. Escherichia coli and Staphylococcus aureus were used as test bacteria. The oscillation contact time was 18 hours and the oscillation temperature was 25°C. The concentration of live bacteria after oscillation culture was calculated to calculate the antibacterial rate.

[0048] Antibacterial rate = (W t -Q t ) / W t ×100%. Wt is the viable bacterial concentration of the blank control sample (CFU / mL). t is the viable bacterial concentration of the experimental sample (CFU / mL).

[0049] Table 2 Antibacterial performance test of non-woven fabrics

[0050] After testing, compared with the blank control sample polypropylene non-woven fabric without antibacterial polypropylene non-woven fabric masterbatch, the non-woven fabrics of Examples 1-3 added with antibacterial polypropylene non-woven fabric masterbatch have significantly improved breaking strength and breaking elongation. This is because the antibacterial polypropylene non-woven fabric masterbatch is composed of cross-linked modified polystyrene and nano zinc oxide, and the modified polystyrene contains alkyl chains, which have good compatibility with polypropylene, thereby enhancing the interface compatibility between the modified polystyrene and the polypropylene resin, and the cross-linked modified polystyrene can play the role of a toughening agent, thereby improving the tensile fracture properties of the polypropylene non-woven fabric.

[0051] The modified polystyrene in Examples 1-3 contains carboxyl groups. During the high-temperature mixing process and the melt extrusion process, the carboxyl groups can form hydrogen bonds with the hydroxyl groups on the surface of the nano zinc oxide, and undergo esterification reactions, thereby grafting the modified polystyrene molecular chains on the surface of the nano zinc oxide. Since the modified polystyrene containing alkyl chains has good compatibility with the polypropylene resin, the modified polystyrene is used as a compatibilizer to improve the compatibility between the nano zinc oxide and the polypropylene resin. The nano zinc oxide with excellent mechanical properties is evenly distributed in the non-woven fabric matrix, further improving the tensile fracture performance of the non-woven fabric. In addition, the nano zinc oxide has excellent antibacterial and bactericidal effects, and is evenly distributed in the non-woven fabric matrix, significantly improving the antibacterial effect of the non-woven fabric on Escherichia coli and Staphylococcus aureus.

[0052] Compared with the blank control sample polypropylene nonwoven fabric, the water contact angle of the nonwoven fabrics of Examples 1-3 is also significantly decreased, and the hydrophilicity is better. This is because the added modified polystyrene contains hydrophilic carboxyl groups, which is beneficial to improving the hydrophilicity of the nonwoven fabric.

[0053] Compared with Example 1, the polystyrene in Comparative Example 1 does not contain an alkyl chain, has poor compatibility with polypropylene resin, and has a low improvement in the mechanical properties of the non-woven fabric. In addition, polystyrene does not contain a carboxyl group, and cannot react with the surface of nano zinc oxide, and cannot act as a compatibilizer, and does not improve the compatibility between nano zinc oxide and polypropylene resin, resulting in poor dispersion of nano zinc oxide, easy agglomeration, and no good improvement of the tensile fracture performance of the non-woven fabric. In addition, the poor dispersion of nano zinc oxide also has a great impact on the antibacterial properties of the non-woven fabric.

[0054] Comparative Example 2: Styrene is reacted with the intermediate, and the obtained modified polystyrene contains carboxyl groups, which can react with the surface of nano zinc oxide, but the modified polystyrene does not contain alkyl chains, has poor compatibility with polypropylene resin, and has a low toughening effect, resulting in lower tensile fracture performance than Example 1. The modified polystyrene contains carboxyl groups, which is beneficial to reducing the surface water contact angle of the polypropylene non-woven fabric and improving the hydrophilicity. And the water contact angle is lower than that of Example 1, which may be because the modified polystyrene of Example 1 contains hydrophobic alkyl long chains, which affects its hydrophilicity.

[0055] In Comparative Example 3, conventional ethylene glycol dimethacrylate and styrene are subjected to cross-linking polymerization reaction. The obtained cross-linked modified polystyrene does not contain an alkyl chain, has poor compatibility with polypropylene resin, and does not contain a carboxyl group. It cannot react with the surface of nano zinc oxide and does not act as a compatibilizer, resulting in poor dispersion of nano zinc oxide and easy agglomeration, and does not improve the tensile fracture properties and antibacterial properties of the non-woven fabric.

[0056] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a masterbatch for antibacterial polypropylene non-woven fabric, characterized in that: The preparation method is: S1. Add deionized water, styrene, functional monomers and emulsifiers into a flask, mix well and add potassium persulfate, stir to react and add ethanol, centrifuge, wash and dry to obtain modified polystyrene; S2, mixing the modified polystyrene, nano zinc oxide and antioxidant in a mixer, and then melt-blending and extruding the materials in a twin-screw extruder to obtain a masterbatch for antibacterial polypropylene non-woven fabric; The structural formula of the functional monomer is shown in formula (1); Formula (1), wherein n is any integer between 8 and 11.

2. The method for preparing the antibacterial polypropylene nonwoven fabric masterbatch according to claim 1, characterized in that: In the S1, the mass of the functional monomer is 15-40% of the mass of styrene.

3. The method for preparing the antibacterial polypropylene nonwoven fabric masterbatch according to claim 1, characterized in that: In S1, the emulsifier is Span 60, Span 80, sodium dodecyl sulfate or sodium dodecylbenzene sulfonate.

4. The method for preparing the antibacterial polypropylene nonwoven fabric masterbatch according to claim 1, characterized in that: In S1, the reaction is carried out at a temperature of 60-75° C. for 18-30 h.

5. The method for preparing the antibacterial polypropylene non-woven fabric masterbatch according to claim 1, characterized in that: The mass of the nano zinc oxide is 10-30% of the mass of the modified polystyrene.

6. The method for preparing the antibacterial polypropylene nonwoven fabric masterbatch according to claim 1, characterized in that: The mixing temperature is 50-80° C., and the mixing time is 30-60 min. The temperature of each section in the twin-screw extruder is 180-200° C., and the screw speed is 200-400 r / min.

7. The method for preparing the antibacterial polypropylene nonwoven fabric masterbatch according to claim 1, characterized in that: The preparation method of the functional monomer is: (1) Add tetrahydrofuran, glycidyl methacrylate and ethylenediamine-N,N'-diacetic acid into a flask, concentrate under reduced pressure to remove low-boiling substances after the reaction, and dry to obtain intermediate A; (2) Place the flask in an ice water bath, add dichloromethane, intermediate A, alkyl acyl chloride, and triethylamine, and stir to react at a temperature of 15-25°C for 12-18 hours. After the reaction, concentrate under reduced pressure, wash, and dry to obtain a functional monomer.

8. The method for preparing the antibacterial polypropylene nonwoven fabric masterbatch according to claim 7, characterized in that: In the above (1), the mass of glycidyl methacrylate is 160-190% of the mass of ethylenediamine-N,N'-diacetic acid.

9. The method for preparing the antibacterial polypropylene nonwoven fabric masterbatch according to claim 7, characterized in that: In the above (1), the reaction is carried out at a temperature of 55-75°C for 24-36 hours.

10. The method for preparing the antibacterial polypropylene nonwoven fabric masterbatch according to claim 7, characterized in that: In (2), the mass of the alkyl acyl chloride is 78-110% of the mass of the intermediate A; the structural formula of the alkyl acyl chloride is , n is any integer between 8 and 11.

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