Preparation method of masterbatch for antibacterial polypropylene non-woven fabric

Abstract

The present invention relates to the technical field of polypropylene, and particularly to a preparation method of a masterbatch for antibacterial polypropylene non-woven fabric. Modified polystyrene, nano-zinc oxide, and an antioxidant are placed in a mixer for mixing, and then the material is melt-blended and extruded into pellets in a twin-screw extruder to obtain the masterbatch for antibacterial polypropylene non-woven fabric. The modified polystyrene in the present invention contains an alkyl chain, and there is good compatibility between the alkyl chain and polypropylene, which can act as a toughening agent to improve the tensile fracture performance of the polypropylene non-woven fabric. The modified polystyrene of the present invention, as a compatibilizer, improves the compatibility between nano-zinc oxide and polypropylene resin, and further improves the tensile fracture performance of the non-woven fabric. Moreover, nano-zinc oxide has excellent antibacterial and bactericidal effects and is uniformly distributed in the non-woven fabric matrix, significantly improving the antibacterial performance of the non-woven fabric.

Description

Technical Field

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

[0002] Polypropylene non-woven fabric has the advantages of light texture, good air permeability, non-toxic and non-irritating, low cost, etc., and is widely used in sanitary protection products, packaging bags and other aspects. Traditional polypropylene non-woven fabric has defects such as poor tensile fracture performance and hydrophilicity, and does not have good antibacterial performance, which limits the development and application of polypropylene non-woven fabric.

[0003] Functional masterbatches such as antibacterial masterbatch, toughening masterbatch, color masterbatch, 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, cross-linked polystyrene rigid particles with better properties can be obtained, which can be used as a toughening agent for materials such as polypropylene to improve the mechanical properties of the materials. However, polystyrene has poor interfacial compatibility with polypropylene, and usually an additional compatibilizer such as PP / PS block copolymer, SBS terpolymer, etc. needs to be added.

[0004] Nano-zinc oxide has excellent mechanical properties and antibacterial properties, and is cheap and easy to obtain, and is widely used in materials such as plastics and fibers. Improving the compatibility between nano-zinc oxide and polymer material groups and improving its dispersion is a research difficulty. 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 and ball-milled, and then mixed with polypropylene resin and extruded to prepare a plastic masterbatch, which can improve the dispersion performance of nano-zinc oxide, thereby enhancing the antibacterial effect of the plastic masterbatch. However, this zinc oxide plastic masterbatch does not improve the mechanical properties of the non-woven fabric. Summary of the Invention

[0005] The present invention solves the problems that the masterbatch for polypropylene non-woven fabric does not have antibacterial properties and has poor mechanical properties.

[0006] The technical solution adopted by the present invention is: A preparation method of a masterbatch for antibacterial polypropylene non-woven fabric is as follows:

[0007] S1. Add deionized water, styrene, functional monomer, emulsifier into a flask, mix well, then add potassium persulfate, stir and react, add ethanol, centrifuge and separate, wash the precipitate with ethanol, and dry to obtain modified polystyrene.

[0008] S2. Mix the modified polystyrene, nano-zinc oxide, and antioxidant in a mixer, and then melt and blend and extrude and pelletize the material in a twin-screw extruder to obtain a masterbatch for antibacterial polypropylene non-woven fabric.

[0009] Further, the structural formula of the functional monomer is as shown in formula (1);

[0010] In formula (1), n is any integer from 8 to 11 in the structural formula.

[0011] Further, in S1, the mass of the functional monomer is 15 - 40% of the mass of styrene.

[0012] Further, in S1, the emulsifier is Span 60, Span 80, sodium dodecyl sulfate or sodium dodecylbenzenesulfonate.

[0013] Further, in S1, the reaction is carried out at a temperature of 60 - 75°C for 18 - 30 h.

[0014] Further, the mass of nano - zinc oxide is 10 - 30% of the mass of modified polystyrene.

[0015] Further, the mixing temperature is 50 - 80°C and the mixing time is 30 - 60 min; the temperatures of each section in the twin - screw extruder are 180 - 200°C, and the screw speed is 200 - 400 r / min.

[0016] Further, the preparation method of the functional monomer is as follows:

[0017] (1) Add tetrahydrofuran, glycidyl methacrylate, and ethylenediamine - N,N’ - diacetic acid into a flask, where the mass of glycidyl methacrylate is 160 - 190% of the mass of ethylenediamine - N,N’ - diacetic acid, react at a temperature of 55 - 75°C for 24 - 36 h, concentrate under reduced pressure to remove low - boiling substances, and dry to obtain intermediate A.

[0018] (2) Place the flask in an ice - water bath, add dichloromethane, intermediate A, alkyl acyl chloride, and triethylamine, where the mass of 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 h, concentrate under reduced pressure after the reaction, wash with petroleum ether, and dry to obtain the functional monomer.

[0019] Further, the structural formula of the alkyl acyl chloride is , n is any integer from 8 to 11.

[0020] Technical effect: The present invention utilizes glycidyl methacrylate and ethylenediamine-N,N'-diacetic acid to carry out ring-opening reaction, and then carries out a preparation reaction with alkyl acyl chloride to obtain a functional monomer containing two alkenyl groups, which can carry out cross-linking polymerization reaction with styrene monomer to obtain cross-linked modified polystyrene. Further, using the modified polystyrene and nano-zinc oxide as the main raw materials, through high-temperature mixing and melt extrusion granulation, a masterbatch for antibacterial polypropylene non-woven fabric is obtained. The modified polystyrene contains an alkyl chain, and there is good compatibility between the alkyl chain and 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 performance of the polypropylene non-woven fabric.

[0021] 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 nano-zinc oxide and undergo esterification reactions, thereby grafting the modified polystyrene molecular chains on the surface of nano-zinc oxide. Since the modified polystyrene containing an alkyl chain has good compatibility with the polypropylene resin, the modified polystyrene is used as a compatibilizer to improve the compatibility between nano-zinc oxide and the polypropylene resin. 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. And 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 against Escherichia coli and Staphylococcus aureus. Description of the drawings

[0022] Figure 1 It is the preparation reaction formula of the functional monomer. Detailed implementation manners

[0023] The following further details the present application in conjunction with embodiments. It should be specifically noted that: for those not indicating specific conditions in the following embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. All raw materials used in the following embodiments can be obtained from ordinary commercial sources unless otherwise specified.

[0024] The average particle size of the nano-zinc oxide of the present invention is 40 nm. The polypropylene resin grade is HL504FB.

[0025] Example 1

[0026] (1) Add 20 mL of tetrahydrofuran, 1.9 g of glycidyl methacrylate, and 1 g of ethylenediamine-N,N'-diacetic acid to a flask, react at a temperature of 60 °C for 24 h, concentrate under reduced pressure to remove low-boiling substances, and dry to obtain intermediate A.

[0027] (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, stir and react at 15 °C for 18 h, concentrate under reduced pressure after the reaction, wash with petroleum ether, and dry to obtain the functional monomer.

[0028] (3) Add 150 mL of deionized water, 20 g of styrene, 3 g of the functional monomer, and emulsifier Span 80 to the flask, mix well, then 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.

[0029] (4) Place 30 g of modified polystyrene, 0.3 g of nano-zinc oxide, and 0.2 g of antioxidant 1010 in a mixer, mix at 50 °C for 60 min, then place the material in a twin-screw extruder, the temperatures of the 1st to 6th sections are 180 °C, 190 °C, 200 °C, 200 °C, 200 °C, 195 °C, the screw speed is 250 r / min, melt-blend and extrude into pellets to obtain the masterbatch for antibacterial polypropylene non-woven fabric.

[0030] Example 2

[0031] (1) Add 20 mL of tetrahydrofuran, 1.8 g of glycidyl methacrylate, and 1 g of ethylenediamine-N,N'-diacetic acid to the flask, react at 55 °C for 36 h, concentrate under reduced pressure to remove low-boiling substances, and dry to obtain intermediate A.

[0032] (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, stir and react at 20 °C for 18 h, concentrate under reduced pressure after the reaction, wash with petroleum ether, and dry to obtain the functional monomer.

[0033] (3) Add 150 mL of deionized water, 20 g of styrene, 5 g of the functional monomer, and emulsifier sodium dodecyl sulfate to the flask, mix well, then 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.

[0034] (4) Place 30 g of modified polystyrene, 0.6 g of nano-zinc oxide, and 0.2 g of antioxidant 1010 in a mixer, mix at 80 °C for 30 min, then place the material in a twin-screw extruder, the temperatures of the 1st to 6th sections are 180 °C, 190 °C, 200 °C, 200 °C, 200 °C, 195 °C, the screw speed is 200 r / min, melt-blend and extrude into pellets to obtain the masterbatch for antibacterial polypropylene non-woven fabric.

[0035] Example 3

[0036] (1) Add 15 mL of tetrahydrofuran, 1.6 g of glycidyl methacrylate, and 1 g of ethylenediamine-N,N'-diacetic acid to a flask, react at 75 °C for 24 h, concentrate under reduced pressure to remove low-boiling substances, and dry to obtain intermediate A.

[0037] (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, stir and react at 25 °C for 12 h, concentrate under reduced pressure after the reaction, wash with petroleum ether, and dry to obtain the functional monomer.

[0038] (3) Add 200 mL of deionized water, 20 g of styrene, 8 g of the functional monomer, and the emulsifier sodium dodecylbenzenesulfonate to a flask, mix well, then 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.

[0039] (4) Place 30 g of modified polystyrene, 0.9 g of nano-zinc oxide, and 0.2 g of antioxidant 1010 in a mixer, mix at 80 °C for 40 min, then place the material in a twin-screw extruder, with the temperatures of the 1st to 6th sections being 180 °C, 190 °C, 200 °C, 200 °C, 200 °C, and 195 °C, and the screw speed being 400 r / min, melt-blend and extrude into pellets to obtain the masterbatch for antibacterial polypropylene non-woven fabric.

[0040] Comparative Example 1

[0041] (1) Add 150 mL of deionized water, 20 g of styrene, and the emulsifier Span 80 to a flask, mix well, then 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.

[0042] (2) Place 30 g of polystyrene, 0.3 g of nano-zinc oxide, and 0.2 g of antioxidant 1010 in a mixer, mix at 50 °C for 60 min, then place the material in a twin-screw extruder, with the temperatures of the 1st to 6th sections being 180 °C, 190 °C, 200 °C, 200 °C, 200 °C, and 195 °C, and the screw speed being 250 r / min, melt-blend and extrude into pellets to obtain the masterbatch for antibacterial polypropylene non-woven fabric.

[0043] Comparative Example 2

[0044] (1) Prepare intermediate A according to the method of Example 1.

[0045] (2) Add 150 mL of deionized water, 20 g of styrene, 3 g of intermediate A, and emulsifier Span 80 into a flask. After mixing evenly, add 0.3 g of potassium persulfate, and react at 75 °C for 18 h. Then add ethanol, perform centrifugal separation, wash the precipitate with ethanol, and dry to obtain modified polystyrene.

[0046] (3) Put 30 g of modified polystyrene, 0.3 g of nano-zinc oxide, and 0.2 g of antioxidant 1010 into a mixer, mix at 50 °C for 60 min. Then, place the material in a twin-screw extruder. The temperatures of the 1st to 6th sections are 180 °C, 190 °C, 200 °C, 200 °C, 200 °C, and 195 °C, and the screw speed is 250 r / min. Melt-blend and extrude into pellets to obtain the masterbatch for antibacterial polypropylene non-woven fabric.

[0047] Comparative Example 3

[0048] (1) Add 150 mL of deionized water, 20 g of styrene, 3 g of ethylene glycol dimethacrylate, and emulsifier Span 80 into a flask. After mixing evenly, add 0.3 g of potassium persulfate, and react at 75 °C for 18 h. Then add ethanol, perform centrifugal separation, wash the precipitate with ethanol, and dry to obtain modified polystyrene.

[0049] (2) Put 30 g of modified polystyrene, 0.3 g of nano-zinc oxide, and 0.2 g of antioxidant 1010 into a mixer, mix at 50 °C for 60 min. Then, place the material in a twin-screw extruder. The temperatures of the 1st to 6th sections are 180 °C, 190 °C, 200 °C, 200 °C, 200 °C, and 195 °C, and the screw speed is 250 r / min. Melt-blend and extrude into pellets to obtain the masterbatch for antibacterial polypropylene non-woven fabric.

[0050] Respectively mix 100 g of the masterbatch for antibacterial polypropylene non-woven fabric prepared in each example and comparative example with 1 kg of polypropylene resin in a mixer, and then extrude and pelletize in a twin-screw extruder. The temperatures of the 1st to 6th sections are 150 °C, 160 °C, 170 °C, 185 °C, 185 °C, and 180 °C, and the screw speed is 250 r / min. After extrusion and pelletization, finally, through the processes of melt blowing, stretching, cooling and shaping, hot air traction, and receiving by a melt-blown fabric equipment, non-woven fabric is made. The melt-blowing process parameters of the melt-blown fabric equipment: the temperatures of the 1st to 4th zones are 170 °C, 210 °C, 225 °C, 230 °C, the temperature of the head 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 40 cm.

[0051] Use the non-woven fabric containing the masterbatch for antibacterial polypropylene non-woven fabric as the experimental sample.

[0052] Use the non-woven fabric prepared from polypropylene resin without adding the masterbatch for antibacterial polypropylene non-woven fabric as the blank control sample.

[0053] Test the breaking performance of non-woven fabric according to the method of FZ / T 60005-1991.

[0054] Test the surface water contact angle of non-woven fabric according to the method of GB / T 42694-2023.

[0055] Table 1 Testing of breaking performance and water contact angle of non-woven fabric

[0056]

[0057] Test the antibacterial performance of non-woven fabric according to the oscillating flask method in the standard of GB / T 20944.3-2008. Escherichia coli and Staphylococcus aureus are used as test strains. The oscillating contact time is 18 h, and the oscillating temperature is 25 °C. Calculate the antibacterial rate based on the viable bacteria concentration after oscillating culture.

[0058] Antibacterial rate = (W t - Q t ) / W t × 100%. Wt is the viable bacteria concentration (CFU / mL) of the blank control sample. Q t is the viable bacteria concentration (CFU / mL) of the experimental sample.

[0059] Table 2 Testing of antibacterial performance of non-woven fabric

[0060]

[0061] After testing, compared with the blank control sample of polypropylene non-woven fabric without antibacterial polypropylene non-woven fabric masterbatch, the breaking strength and elongation at break of the non-woven fabrics in Examples 1-3 are significantly improved after adding the antibacterial polypropylene non-woven fabric masterbatch. This is because the antibacterial polypropylene non-woven fabric masterbatch is composed of crosslinked modified polystyrene and nano-zinc oxide. The modified polystyrene contains alkyl chains, and there is good compatibility between the alkyl chains and polypropylene, thus enhancing the interfacial compatibility between the modified polystyrene and polypropylene resin. Moreover, the crosslinked modified polystyrene can act as a toughening agent, thereby improving the tensile breaking performance of polypropylene non-woven fabric.

[0062] 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 nano-zinc oxide and undergo an esterification reaction, thereby grafting the molecular chains of modified polystyrene onto the surface of nano-zinc oxide. Since the modified polystyrene containing alkyl chains has good compatibility with polypropylene resin, the modified polystyrene serves as a compatibilizer, improving the compatibility between nano-zinc oxide and polypropylene resin. The nano-zinc oxide with excellent mechanical properties is evenly distributed in the non-woven fabric matrix, further enhancing the tensile fracture performance of the non-woven fabric. Moreover, 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 against Escherichia coli and Staphylococcus aureus.

[0063] Compared with the blank control sample of polypropylene non-woven fabric, the water contact angle of the non-woven fabrics in Examples 1-3 also decreased significantly, showing better hydrophilicity. This is because the added modified polystyrene contains hydrophilic carboxyl groups, which is beneficial to improving the hydrophilicity of the non-woven fabric.

[0064] Compared with Example 1, the polystyrene in Comparative Example 1 does not contain alkyl chains and has poor compatibility with polypropylene resin, resulting in a lower improvement in the mechanical properties of the non-woven fabric. Moreover, the polystyrene does not contain carboxyl groups and cannot interact with the surface of nano-zinc oxide, failing to act as a compatibilizer and improve the compatibility between nano-zinc oxide and polypropylene resin. This leads to poor dispersion of nano-zinc oxide, easy agglomeration, and failure to effectively improve 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 performance of the non-woven fabric.

[0065] In Comparative Example 2, styrene was reacted with an intermediate to obtain modified polystyrene containing carboxyl groups, which can interact with the surface of nano-zinc oxide. However, the modified polystyrene does not contain alkyl chains and has poor compatibility with polypropylene resin, resulting in a lower toughening effect and a tensile fracture performance lower than that of Example 1. The carboxyl groups in this modified polystyrene are beneficial to reducing the surface water contact angle of the polypropylene non-woven fabric and improving its hydrophilicity. Moreover, the water contact angle is lower than that of Example 1, probably because the modified polystyrene in Example 1 contains hydrophobic alkyl long chains, which affect its hydrophilicity.

[0066] In Comparative Example 3, conventional ethylene glycol dimethacrylate and styrene were used for cross-linking polymerization reaction to obtain cross-linked modified polystyrene, which also does not contain alkyl chains, has poor compatibility with polypropylene resin, and does not contain carboxyl groups, so it cannot interact with the surface of nano-zinc oxide and fails to act as a compatibilizer. This leads to poor dispersion of nano-zinc oxide, easy agglomeration, and failure to effectively improve the tensile fracture performance and antibacterial performance of the non-woven fabric.

[0067] Although embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and 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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