Bio-based antibacterial material, preparation method thereof and refrigerator

Abstract

The invention discloses a bio-based antibacterial material, a preparation method thereof and a refrigerator, and belongs to the field of antibacterial materials. According to the technical scheme, the antibacterial polylactic acid material comprises polylactic acid and an antibacterial agent, the antibacterial agent is a two-dimensional single-layer R4N-coated ZrP nanosheet, the length-diameter ratio of the two-dimensional single-layer R4N-coated ZrP nanosheet is greater than 600: 1, and the specific surface area of the two-dimensional single-layer R4N-coated ZrP nanosheet is greater than 240 m < 2 > / g. The material is applied to the aspect of refrigerator antibacterial materials, and the problems that polylactic acid is weak in antibacterial activity, insufficient in heat resistance and toughness and poor in compatibility with zirconium hydrogen phosphate, and consequently performance improvement is limited are solved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of antibacterial materials, and particularly relates to a bio-based antibacterial material, a preparation method thereof and a refrigerator. BACKGROUND

[0002] Bio-based degradable materials have many advantages such as renewability and environmental friendliness, and meet the concept of sustainable development. In recent years, they have received extensive attention and vigorous development worldwide. Compared with traditional petroleum-based materials, bio-based materials can effectively reduce the dependence on non-renewable resources and reduce carbon emissions in the production process, which meets the strategic direction of green development of home appliance enterprises. However, during the use of home appliances, due to factors such as environmental humidity and suitable temperature, various microorganisms are easy to breed on the surface of home appliances, which not only affects the service life of home appliances, but also may pose a threat to human health. Therefore, the application of antibacterial function in the field of home appliances is crucial. At present, the mainstream scheme for imparting long-acting antibacterial function to plastics mainly relies on metal ions such as silver and copper, but the dissolution and accumulation of metal ions have potential environmental and health risks, and may affect the appearance and processing rheological properties of the material.

[0003] Poly lactic acid (PLA) is one of the most widely used and most potential bio-based degradable resins, which is derived from starch crops such as corn and sugarcane, and is formed by microbial fermentation of lactic acid and polymerization. It has the advantages of biodegradability, non-toxicity and biocompatibility. However, the antibacterial effect of poly lactic acid is limited, and the heat resistance and toughness are insufficient, which is difficult to meet the demand of home appliances and other fields which require high heat resistance and impact resistance. Zirconium hydrogen phosphate (ZrP) is a layered inorganic compound with regular lattice, which has excellent thermal stability, chemical stability and ion exchange capacity. If zirconium hydrogen phosphate can be introduced into the poly lactic acid matrix, it is expected to simultaneously improve the heat resistance and mechanical properties of the material. However, since unmodified ZrP is an inorganic filler and PLA is an organic material, the polarity difference between them is large, and the compatibility is poor, which leads to easy aggregation of ZrP lamella and weak interfacial bonding between ZrP and PLA, thereby limiting its application in the field of home appliances.

[0004] Therefore, it has become an important technical problem to be solved in this field to develop a composite material that can simultaneously improve the heat resistance, toughness and long-acting antibacterial performance of PLA without introducing metal ions, and overcome the poor compatibility of ZrP and PLA. SUMMARY

[0005] In view of the deficiencies of the prior art, the technical problem to be solved by the present application is the weak antibacterial activity of poly lactic acid, the insufficient heat resistance and toughness, and the poor compatibility of poly lactic acid and zirconium hydrogen phosphate, which limits the performance improvement. A bio-based antibacterial material with excellent biodegradability, heat resistance and mechanical properties and long-acting antibacterial efficiency, a preparation method thereof and a refrigerator are provided.

[0006] To solve the technical problem, the technical scheme adopted by the present application is:

[0007] The present application provides a bio-based antibacterial material comprising polylactic acid and an antibacterial agent.

[0008] The antibacterial agent is a two-dimensional monolayer R4N@ZrP nanosheet, and the aspect ratio of the two-dimensional monolayer R4N@ZrP nanosheet is >600:1, and the specific surface area is >240m 2 / g.

[0009] In some embodiments, the two-dimensional monolayer R4N@ZrP nanosheet is prepared by intercalating butylamine into zirconium hydrogen phosphate ZrP and then using long-chain quaternary ammonium salt R4N+ to enter the interlayer through ion exchange.

[0010] In some embodiments, the bio-based antibacterial material further comprises a nucleating agent and an anti-hydrolysis agent.

[0011] In some embodiments, the polylactic acid is a copolymer of levorotatory polylactic acid and dextrorotatory polylactic acid, and the melt index is 1.5-10 g / min.

[0012] The long-chain quaternary ammonium salt is one or more of cetyltrimethylammonium bromide, didodecyl dimethyl ammonium bromide, benzyl quaternary ammonium salt, polyquaternary ammonium salt, hydroxypropyl quaternary ammonium salt, and heterocyclic quaternary ammonium salt.

[0013] The nucleating agent is one or more of PCL, PBS, PBAT, talc, silicon dioxide, montmorillonite, and organic carboxylate.

[0014] The anti-hydrolysis agent is one or more of inositol, an epoxy compound, antioxidant 1010, antioxidant 1076, monocarbodiimide, and polycarbodiimide.

[0015] In some embodiments, the bio-based antibacterial material comprises 90-100 parts by weight of polylactic acid, 0.5-10 parts by weight of antibacterial agent, 1-2 parts by weight of nucleating agent, and 0.5-2 parts by weight of anti-hydrolysis agent.

[0016] The present application provides another aspect of a preparation method of the above-mentioned bio-based antibacterial material, comprising a preparation step of an antibacterial agent.

[0017] The preparation step of the antibacterial agent comprises:

[0018] Zirconium hydrogen phosphate is added to butylamine, and a pre-product is obtained by ultrasonic treatment.

[0019] The pre-product and the long-chain quaternary ammonium salt are added to anhydrous ethanol, and the antibacterial agent is obtained by ultrasonic treatment.

[0020] In some embodiments, the zirconium hydrogen phosphate is added to the butylamine, ultrasonic stirring is performed at 50-70 DEG C for 1-2h, the ultrasonic power is 2-4kW, then cooling, centrifugation is performed to obtain a first precipitate, washing, drying is performed to obtain a pre-product;

[0021] The pre-product and the long-chain quaternary ammonium salt are added to anhydrous ethanol, ultrasonic stirring is performed at 50-70 DEG C for 0.5-2.5h, the ultrasonic power is 4-6kW, then cooling, centrifugation is performed to obtain a second precipitate, washing, drying is performed to obtain the antibacterial agent.

[0022] In some embodiments, the adding amount of the zirconium hydrogen phosphate, the butylamine, the long-chain quaternary ammonium salt and the anhydrous ethanol is 1g: 1.5-8g: 15-25g: 5-15mL.

[0023] In some embodiments, the preparation method further comprises a melt blending step and a molding step, wherein:

[0024] The melt blending step comprises: pre-stirring the polylactic acid, the nucleating agent and the anti-hydrolysis agent, then adding and stirring the antibacterial agent, and then melt blending to obtain the composite particles;

[0025] The molding step comprises: molding the composite particles by an extrusion or injection molding process.

[0026] The application further provides a refrigerator, wherein the raw material of the refrigerator comprises the above-mentioned bio-based antibacterial material.

[0027] Compared with the prior art, the application has the following beneficial effects:

[0028] The application provides a bio-based antibacterial material, which uses bio-based polylactic acid with natural antibacterial performance as a resin matrix, and uses two-dimensional monolayer R4N@ZrP nanosheets prepared by intercalation modification of zirconium hydrogen phosphate with quaternary ammonium salt as an antibacterial agent. The two-dimensional monolayer R4N@ZrP nanosheets have a higher aspect ratio and a larger specific surface area, the effective bactericidal and bacteriostatic area is greatly improved, and the nanometer effect is significant, and the interface interaction with the PLA is closer. The zirconium hydrogen phosphate R4N@ZrP modified by grafting of the quaternary ammonium salt has a large number of long-chain alkanes grafted on the surface, and the compatibility and interface bonding force with the PLA resin matrix are further improved.

[0029] The application provides a preparation method of a bio-based antibacterial material, which comprises the following steps: intercalation modification of ZrP with a small molecule butylamine to increase the layer spacing; then, long-chain quaternary ammonium salt R4N+ is introduced into the layer by ion exchange, and the ZrP is peeled off by combining ultrasonic and blending processes to prepare nanosheet material R4N@ZrP with a two-dimensional monolayer nanostructure, which serves as a heterogeneous nucleation point to promote the transformation of the metastable alpha' crystal form to the alpha crystal form, and the heat resistance temperature reaches 100 DEG C. It is further stated that the nanostructure characteristics of R4N@ZrP not only improve the antibacterial rate, but also synergistically promote the crystal form transformation, improve the interface bonding strength and greatly improve the heat resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Schematic diagram of the two-step intercalation modification of ZrP provided by an embodiment of the present invention;

[0031] Figure 2 This is a scanning electron microscope image of the R4N@ZrP material and ZrP provided in Example 3 of the present invention;

[0032] Figure 3 This is a scanning electron microscope image of R4N@ZrP provided in Comparative Example 4 of the present invention without the ultrasonic treatment;

[0033] Figure 4 This is a comparison chart of the compatibility of the R4N@ZrP material and ZrP with the PLA matrix provided in the embodiments of the present invention. DETAILED DESCRIPTION

[0034] The following is a detailed and complete description of the technical solutions in specific embodiments of the present invention, with reference to the accompanying drawings. It should be understood that the described embodiments are merely partial implementations of the overall technical solution of the present invention, and are not exhaustive. All other embodiments derived by those skilled in the art based on the overall concept of the present invention are intended to fall within the scope of protection of the present invention.

[0035] A bio-based antibacterial material comprises polylactic acid.

[0036] Polylactic acid is one of the most widely used and most promising biodegradable resins. It is derived from starch crops such as corn and sugarcane, and is formed by microbial fermentation of lactic acid and polymerization. It has the advantages of being degradable, non-toxic, and biocompatible. In some embodiments, the polylactic acid is a copolymer of left-handed polylactic acid and right-handed polylactic acid, and has a melt index of 1.5-10 g / min. The above technical solution defines the polylactic acid as a copolymer of left-handed polylactic acid and right-handed polylactic acid, and its melt index is 1.5-10 g / min. The reason is that pure left-handed polylactic acid has high crystallinity and high brittleness; the introduction of a small amount of right-handed monomer can reduce the symmetry of the molecular chain, inhibit excessive crystallization, and improve the flexibility and processability of the material, making it suitable for applications such as injection molding, blister molding, and extrusion.

[0037] It is understandable that the above-mentioned polylactic acid can also be other types of resins such as polyethylene (PE), polypropylene (PP), polystyrene (PS), polybutylene terephthalate (PBAT), acrylonitrile-butadiene-styrene copolymer (ABS), etc.

[0038] A bio-based antibacterial material includes an antibacterial agent, wherein the antibacterial agent is a two-dimensional single-layer R4N@ZrP nanosheet, the two-dimensional single-layer R4N@ZrP nanosheet has an aspect ratio of >600:1 and a specific surface area of ​​>240m 2 / g. The two-dimensional monolayer R4N@ZrP nanosheet is prepared by butylamine intercalation modification of zirconium hydrogen phosphate ZrP and then using long-chain quaternary ammonium salt R4N+ to enter the interlayer by ion exchange. In some embodiments, the long-chain quaternary ammonium salt is one or more of cetyltrimethylammonium bromide, didodecyldimethylammonium bromide, benzyl quaternary ammonium salt, polyquaternary ammonium salt, hydroxypropyl quaternary ammonium salt, and heterocyclic quaternary ammonium salt.

[0039] The above-mentioned biobased antibacterial material uses polylactic acid, which has the advantages of biodegradability, non-toxicity, biocompatibility, etc. However, due to the limited antibacterial effect, insufficient heat resistance and toughness of polylactic acid, it is difficult to meet the requirements of household appliances and other fields which require high heat resistance and impact resistance. In order to improve the long-term antibacterial performance and improve the heat resistance and toughness, the present application composites zirconium hydrogen phosphate and polylactic acid. Zirconium hydrogen phosphate is a layered inorganic compound with regular crystal lattice, which has excellent thermal stability, chemical stability and ion exchange capacity. If zirconium hydrogen phosphate with antibacterial ability is introduced into the polylactic acid matrix, it is expected to improve the antibacterial performance, heat resistance and mechanical properties of the material. However, since unmodified ZrP is an inorganic filler and PLA is an organic polymer resin, the polarity difference between the two is large, and the compatibility is poor, which leads to easy aggregation of ZrP sheet and weak interfacial bonding force between ZrP and PLA resin, thereby limiting its application in the field of household appliances. Therefore, the present application prepares two-dimensional monolayer R4N@ZrP nanosheet as an antibacterial agent by intercalation modification of zirconium hydrogen phosphate with quaternary ammonium salt. The two-dimensional monolayer R4N@ZrP nanosheet has a higher aspect ratio and a larger specific surface area, and the effective bactericidal and bacteriostatic area is greatly improved, and the nanoeffect is significant. The zirconium hydrogen phosphate R4N@ZrP modified by quaternary ammonium salt grafting has a large number of long-chain alkanes grafted on the surface, which further improves the compatibility and interfacial bonding force with the PLA resin matrix. At the same time, as a heterogeneous nucleation point and a higher specific surface area, it promotes the transformation of metastable alpha' crystal form to stable alpha crystal form, effectively improves the thermal stability of quaternary ammonium salt and the heat distortion temperature of PLA, and increases the heat resistance temperature to more than 100℃. Through accelerated aging test, the aging time is more than 168 hours, and the corresponding actual effective antibacterial life is more than 5 years, which improves the long-term antibacterial property.

[0040] The above technical solution further limits the preparation of two-dimensional monolayer R4N@ZrP nanosheet by butylamine pre-intercalation modification of zirconium hydrogen phosphate ZrP and then using long-chain quaternary ammonium salt R4N+ to enter the interlayer by ion exchange. The reason is that the interlayer spacing of ZrP can be increased by intercalation modification with small molecule butylamine, which is beneficial to the ion exchange of long-chain quaternary ammonium salt R4N+ into the interlayer.

[0041] The above technical solution further limits the selection of long-chain quaternary ammonium salt and its specific type. The reason is that short-chain quaternary ammonium salt can only increase the interlayer spacing of zirconium hydrogen phosphate, but cannot strip it into a monolayer. Long-chain quaternary ammonium salt can further strip zirconium hydrogen phosphate into a two-dimensional monolayer structure. In addition, organic long-chain quaternary ammonium salt can improve the compatibility with the resin matrix PLA.

[0042] It can be understood that the above-mentioned zirconium hydrogen phosphate includes nano zirconium hydrogen phosphate and micron zirconium hydrogen phosphate.

[0043] A bio-based antibacterial material includes a nucleating agent. In some embodiments, the nucleating agent is one or more of PCL, PBS, PBAT, talc, silica, montmorillonite, and organic carboxylate. The nucleating agent promotes the rapid formation of crystals during the crystallization process by providing additional crystal nucleus sites, thereby increasing the crystallization rate, enhancing the mechanical properties and heat resistance of the polymer, and improving the appearance quality, such as surface smoothness and transparency. The present application improves the crystallinity by adding a nucleating agent, slows down the diffusion rate of water molecules, reduces the hydrolysis rate, thereby prolonging the service life in a humid environment and maintaining its performance.

[0044] A bio-based antibacterial material includes an anti-hydrolysis agent. In some embodiments, the anti-hydrolysis agent is one or more of inositol, an epoxide compound, antioxidant 1010, antioxidant 1076, a mono-carbodiimide, and a multi-carbodiimide. The anti-hydrolysis agent maintains the stability of the molecular structure of the polymer by preventing or reducing the hydrolysis rate caused by the reaction of the polymer with water, thereby prolonging the service life of the material in a humid environment and maintaining its performance.

[0045] In some embodiments, the bio-based antibacterial material includes 90-100 parts by weight of polylactic acid, 0.5-10 parts by weight of an antibacterial agent, 1-2 parts by weight of a nucleating agent, and 0.5-2 parts by weight of an anti-hydrolysis agent.

[0046] The above technical solution limits the amount of polylactic acid, antibacterial agent, nucleating agent, and anti-hydrolysis agent. It can be understood that the amount of polylactic acid can also be 92 parts, 94 parts, 96 parts, 98 parts, and any point value within the range thereof, the amount of antibacterial agent can also be 2 parts, 4 parts, 6 parts, 8 parts, and any point value within the range thereof, the amount of nucleating agent can also be 1.2 parts, 1.4 parts, 1.6 parts, 1.8 parts, and any point value within the range thereof, and the amount of anti-hydrolysis agent can also be 0.75 parts, 1 part, 1.25 parts, 1.5 parts, 1.75 parts, and any point value within the range thereof.

[0047] Another aspect of the present application provides a preparation method of the above-mentioned bio-based antibacterial material, which includes a preparation step of an antibacterial agent; as shown in Figure 1 The preparation step of the antibacterial agent includes:

[0048] Zirconium hydrogen phosphate is added to butylamine to obtain a pre-product by ultrasonic treatment; the pre-product is added to a long-chain quaternary ammonium salt solution to obtain an antibacterial agent by ultrasonic treatment.

[0049] In the preparation steps of the above-mentioned antibacterial agent, ZrP is modified by intercalation of small molecule butylamine to increase the interlayer spacing; then, long-chain quaternary ammonium salt R4N+ is used to enter the interlayer through ion exchange, and the ZrP is exfoliated by combining ultrasound and blending processes to prepare a single-layer two-dimensional nanostructured nanosheet R4N@ZrP with a large specific surface area and dispersion stability.

[0050] In some embodiments, the steps of preparing the antibacterial agent include:

[0051] S1. Zirconium hydrogen phosphate was added to butylamine, and ultrasonic stirring was performed at 50-70 ° C for 1-2 h at an ultrasonic power of 2-4 kW, followed by cooling and centrifugation to obtain a first precipitate, which was washed and dried to obtain a pre-product;

[0052] S2. Add the pre-product to a long-chain quaternary ammonium salt solution, ultrasonicate at 50-70°C for 0.5-2.5h with an ultrasonic power of 4-6kW, and then cool and centrifuge to obtain a second precipitate, which is washed and dried to obtain an antibacterial agent.

[0053] In the preparation steps of the above-mentioned antibacterial agent, butylamine pre-intercalation is the key process. By ultrasonically pre-supporting zirconium hydrogen phosphate with butylamine, the interlayer spacing can be expanded, opening a "channel" for long-chain quaternary ammonium salts to enter the interlayer, effectively improving the quaternary ammonium salt grafting efficiency, and greatly improving the peeling of multi-layer zirconium hydrogen phosphate into a single-layer structure. Figure 2 The scanning electron microscope images of the R4N@ZrP material and ZrP provided in Example 3 of this application are shown in FIG. Figure 2 It can be seen that the two-dimensional single-layer R4N@ZrP nanosheets were successfully prepared. Figure 3 The scanning electron microscope image of R4N@ZrP without ultrasonic treatment provided in Comparative Example 4 is shown in FIG. Figure 3 It can be seen from the figure that the R4N@ZrP prepared without ultrasonic process is multilayer R4N@ZrP nanosheets.

[0054] The above technical solution also limits the power of the ultrasonic wave used for the butylamine pre-intercalation. The reason is that if the intercalation power is too low, the force driving the butylamine into the interlayer will be weakened, and the intercalation efficiency will decrease. If the intercalation power is too high, the temperature will rise too quickly in a short period of time, and the butylamine will be easily volatilized, which will also reduce the intercalation efficiency.

[0055] In some embodiments, the ratio of the added amounts of zirconium hydrogen phosphate, butylamine, long-chain quaternary ammonium salt and anhydrous ethanol is 1 g: 1.5-8 g: 15-25 g: 5-15 mL.

[0056] In some embodiments, the preparation method further comprises a melt blending step and a molding step, wherein:

[0057] The melt blending step includes: pre-mixing polylactic acid, a nucleating agent, and an anti-hydrolysis agent, then adding an antibacterial agent and mixing, and then melt blending to prepare composite particles;

[0058] The forming step comprises forming the composite particles by an extrusion or injection molding process.

[0059] The application also provides a refrigerator, raw materials of the refrigerator comprising the above-mentioned bio-based antibacterial material.

[0060] In order to more clearly and specifically introduce the bio-based antibacterial material, the preparation method thereof and the refrigerator provided by the embodiments of the application, the following will be described in combination with specific embodiments.

[0061] Embodiment 1

[0062] Preparation of the bio-based antibacterial material

[0063] 1. Raw material composition: PLA 90 parts, antibacterial agent 10 parts, nucleating agent 1.0 part, hydrolysis inhibitor 1.5 parts;

[0064] 2. Preparation steps:

[0065] (1) Preparation of the antibacterial agent:

[0066] 1g of zirconium hydrogen phosphate is added to 5g of butylamine solution, ultrasonic stirring is performed in a 50℃ constant temperature water bath for 1.5 hours, the ultrasonic power is 3kw, after cooling, centrifugation is performed, the supernatant is removed, and a first precipitate is obtained, which is washed with anhydrous ethanol for 5 times, and dried in a 60℃ oven for 2 hours to obtain a pre-product;

[0067] 1g of the pre-product and 15g of long-chain quaternary ammonium salt are respectively added to 10ml of anhydrous ethanol, ultrasonic stirring is performed in a 50℃ constant temperature water bath for 2 hours, the ultrasonic power is 5kw, after cooling, centrifugation is performed, the supernatant is removed, and a second precipitate is obtained, which is washed with anhydrous ethanol for 5 times, and placed in a 60℃ oven for drying for 24 hours to obtain the antibacterial agent;

[0068] The above-mentioned antibacterial agent is a two-dimensional monolayer R4N@ZrP nanosheet, the aspect ratio is 600:1, and the specific surface area is 240m 2 / g;

[0069] The testing method of the aspect ratio and the specific surface area is as follows:

[0070] The testing method of the aspect ratio is as follows: the agglomeration interference is eliminated by ultrasonic-centrifugal gradient dispersion pretreatment, the thickness (h) is measured by atomic force microscopy (AFM), the lateral size (L) is counted by scanning electron microscopy (SEM), and then the aspect ratio = L / h is calculated;

[0071] The testing method of the specific surface area is as follows: the specific surface area is calculated by determining the adsorption amount of the measured zirconium hydrogen phosphate to the adsorbate molecules (nitrogen) according to the gas concentration change before and after adsorption by using the dynamic BET method;

[0072] The testing method of the remaining embodiments and the comparative examples is the same as that of the present embodiment.

[0073] (2) Preparation of the composite material:

[0074] First, dry the PLA at 60°C for 6h, add PLA, nucleating agent, anti-hydrolysis agent into the high-speed mixer, pre-stir at room temperature, then add the antibacterial agent and mix and stir, then melt blend at 180°C, 60rpm / min to prepare the composite particles, which can be molded by injection molding process;

[0075] The above PLA is 4032D produced by Nature Works, zirconium hydrogen phosphate CAS No. 13772-29-7, long-chain quaternary ammonium salt is cetyltrimethylammonium bromide, nucleating agent is PBS, and anti-hydrolysis agent is inositol.

[0076] Example 2

[0077] Preparation of biobased antibacterial material

[0078] 1. Raw material composition: PLA 92.5 parts, antibacterial agent 7.5 parts, nucleating agent 1.25 parts, anti-hydrolysis agent 1.5 parts;

[0079] 2. Preparation steps:

[0080] (1) Preparation of antibacterial agent:

[0081] Add 1g of zirconium hydrogen phosphate to 5g of butylamine solution, ultrasonically stir in a 50°C constant temperature water bath for 1.5 hours, the ultrasonic power is 3kW, centrifuge after cooling, remove the supernatant, get the first precipitate, wash with anhydrous ethanol 5 times, dry in a 60°C oven for 2 hours, get the pre-product;

[0082] Add 1g of pre-product and 25g of long-chain quaternary ammonium salt to 15ml of anhydrous ethanol respectively, ultrasonically stir in a 50°C constant temperature water bath for 2 hours, the ultrasonic power is 5kw, centrifuge after cooling, remove the supernatant, get the second precipitate, wash with anhydrous ethanol 5 times, place in a 60°C oven for drying for 24 hours, get the antibacterial agent;

[0083] The above antibacterial agent is two-dimensional monolayer R4N@ZrP nanosheet, the aspect ratio is 620:1, and the specific surface area is 250m 2 / g.

[0084] (2) Preparation of the composite material:

[0085] First, dry the PLA at 60°C for 6h, add PLA, nucleating agent, anti-hydrolysis agent into the high-speed mixer, pre-stir at room temperature, then add the antibacterial agent and mix and stir, then melt blend at 180°C, 60rpm / min to prepare the composite particles, which can be molded by injection molding process;

[0086] The PLA is 4032D produced by Nature Works, the zirconium hydrogen phosphate is CAS No. 13772-29-7, the long-chain quaternary ammonium salt is didodecyldimethylammonium bromide, the nucleating agent is PCL, and the anti-hydrolysis agent is polycarbodiimide.

[0087] Example 3

[0088] Preparation of biobased antibacterial material

[0089] 1. Raw material composition: PLA 95 parts, antibacterial agent 5 parts, nucleating agent 1.5 parts, anti-hydrolysis agent 1.5 parts;

[0090] 2. Preparation steps:

[0091] (1) Preparation of antibacterial agent:

[0092] 1g of zirconium hydrogen phosphate was added to 8g of butylamine solution, and ultrasonic stirring was carried out in a constant temperature water bath at 50°C for 1.5 hours, the ultrasonic power was 3kW, and after cooling, centrifugation was carried out, the supernatant was removed, and the first precipitate was obtained, which was washed with anhydrous ethanol for 5 times, and dried in a 60°C oven for 2 hours to obtain the product;

[0093] 1g of the pre-product and 20g of long-chain quaternary ammonium salt were added to 15ml of anhydrous ethanol, and ultrasonic stirring was carried out in a constant temperature water bath at 50°C for 2 hours, the ultrasonic power was 5kw, and after cooling, centrifugation was carried out, the supernatant was removed, and the second precipitate was obtained, which was washed with anhydrous ethanol for 5 times, and placed in a 60°C oven for drying for 24 hours to obtain the antibacterial agent;

[0094] The above antibacterial agent is a two-dimensional monolayer R4N@ZrP nanosheet, the aspect ratio is 650:1, and the specific surface area is 260m 2 / g.

[0095] (2) Preparation of composite material:

[0096] First, the PLA was dried at 60°C for 6h, the PLA, nucleating agent, anti-hydrolysis agent were added to a high-speed mixer for pre-stirring, then the antibacterial agent was added and mixed and stirred, and then melt blending was carried out at 180°C, 60rpm / min to prepare composite particles, which can be molded by injection molding process;

[0097] The PLA is 4032D produced by Nature Works, the zirconium hydrogen phosphate is CAS No. 13772-29-7, the long-chain quaternary ammonium salt is didodecyldimethylammonium bromide, the nucleating agent is PCL, and the anti-hydrolysis agent is polycarbodiimide.

[0098] Example 4

[0099] Preparation of biobased antibacterial material

[0100] 1. Raw material composition: PLA 97.5 parts, antibacterial agent 2.5 parts, nucleating agent 1.75 parts, anti-hydrolysis agent 1.5 parts;

[0101] 2. Preparation steps:

[0102] (1) Preparation of antibacterial agent (two-dimensional monolayer R4N@ZrP nanosheet):

[0103] 1 g of zirconium hydrogen phosphate was added to 1.5 g of butylamine solution, and ultrasonic stirring was carried out in a constant temperature water bath at 50°C for 1.5 hours, the ultrasonic power was 3 kW, and after cooling, centrifugation was carried out, the supernatant was removed, and the first precipitate was obtained, which was washed with anhydrous ethanol for 5 times, and dried in an oven at 60°C for 2 hours to obtain the product;

[0104] 1 g of the pre-product and 20 g of long-chain quaternary ammonium salt were added to 15 ml of anhydrous ethanol respectively, and ultrasonic stirring was carried out in a constant temperature water bath at 50°C for 2 hours, the ultrasonic power was 5 kw, and after cooling, centrifugation was carried out, the supernatant was removed, and the second precipitate was obtained, which was washed with anhydrous ethanol for 5 times, and placed in an oven at 60°C for drying for 24 hours to obtain the antibacterial agent;

[0105] The above antibacterial agent is a two-dimensional monolayer R4N@ZrP nanosheet, the aspect ratio is 650:1, and the specific surface area is 262 m 2 / g.

[0106] (2) Preparation of composite material:

[0107] First, the PLA was dried at 60°C for 6h, the PLA, nucleating agent, anti-hydrolysis agent were added to a high-speed mixer for pre-stirring, then the antibacterial agent was added and mixed and stirred, and then melt blending was carried out at 180°C, 60 rpm / min to prepare composite particles, which can be molded by injection molding process;

[0108] The above PLA is 4032D produced by Nature Works, the zirconium hydrogen phosphate is CAS No. 13772-29-7, the long-chain quaternary ammonium salt is cetyltrimethylammonium bromide, the nucleating agent is montmorillonite, and the anti-hydrolysis agent is inositol.

[0109] Example 5

[0110] Preparation of bio-based antibacterial material

[0111] 1. Raw material composition: PLA 97.5 parts, antibacterial agent 2.5 parts, nucleating agent 1.75 parts, anti-hydrolysis agent 1.5 parts;

[0112] 2. Preparation steps:

[0113] (1) Preparation of antibacterial agent:

[0114] 1 g of zirconium hydrogen phosphate was added to 3 g of butylamine solution, and ultrasonic stirring was performed in a constant temperature water area of ​​50°C for 1.5 hours with an ultrasonic power of 3 kW. After cooling, the solution was centrifuged and the supernatant was removed to obtain a first precipitate, which was washed with anhydrous ethanol 5 times and dried in an oven at 60°C for 2 hours to obtain the product;

[0115] 1 g of the pre-product and 15 g of the long-chain quaternary ammonium salt were added to 15 ml of anhydrous ethanol respectively, and ultrasonically stirred for 2 hours in a constant temperature water area of ​​50°C with an ultrasonic power of 5 kW. After cooling, the mixture was centrifuged and the supernatant was removed to obtain a second precipitate, which was washed with anhydrous ethanol 5 times and dried in an oven at 60°C for 24 hours to obtain an antibacterial agent.

[0116] The antibacterial agent is a two-dimensional single-layer R4N@ZrP nanosheet with an aspect ratio of 610:1 and a specific surface area of ​​243m 2 / g.

[0117] (2) Preparation of composite materials:

[0118] First, PLA was dried at 60°C for 6 hours, PLA, nucleating agent, and anti-hydrolysis agent were added to a high-speed mixer and pre-stirred, and then antibacterial agent was added and mixed, and then melt-blended at 180°C and 60 rpm / min to prepare composite particles, which could be formed by injection molding.

[0119] The PLA is 4032D produced by Nature Works, the zirconium hydrogen phosphate is CAS No. 13772-29-7, the long-chain quaternary ammonium salt is benzyl quaternary ammonium salt, the nucleating agent is PBS, and the anti-hydrolysis agent is inositol.

[0120] Example 6

[0121] Preparation of bio-based antibacterial materials

[0122] 1. Raw material composition: PLA 95 parts, antibacterial agent 5 parts, nucleating agent 1.5 parts, anti-hydrolysis agent 0.5 parts;

[0123] 2. Preparation steps:

[0124] (1) Preparation of antibacterial agent:

[0125] 1 g of zirconium hydrogen phosphate was added to 4.5 g of butylamine solution, and ultrasonic stirring was performed in a constant temperature water area of ​​50°C for 1.5 hours with an ultrasonic power of 3 kW. After cooling, the mixture was centrifuged and the supernatant was removed to obtain a first precipitate, which was washed with anhydrous ethanol 5 times and dried in an oven at 60°C for 2 hours to obtain the product;

[0126] 1 g of the pre-product and 15 g of the long-chain quaternary ammonium salt were added to 15 ml of anhydrous ethanol respectively, and ultrasonically stirred for 2 hours in a constant temperature water area of ​​50°C with an ultrasonic power of 5 kW. After cooling, the mixture was centrifuged and the supernatant was removed to obtain a second precipitate, which was washed with anhydrous ethanol 5 times and dried in an oven at 60°C for 24 hours to obtain an antibacterial agent.

[0127] The antibacterial agent is a two-dimensional single-layer R4N@ZrP nanosheet with an aspect ratio of 615:1 and a specific surface area of ​​245m 2 / g.

[0128] (2) Preparation of composite materials:

[0129] First, PLA was dried at 60°C for 6 hours, PLA, nucleating agent, and anti-hydrolysis agent were added to a high-speed mixer and pre-stirred, and then antibacterial agent was added and mixed, and then melt-blended at 180°C and 60 rpm / min to prepare composite particles, which could be formed by injection molding.

[0130] The PLA is 4032D produced by Nature Works, the zirconium hydrogen phosphate is CAS No. 13772-29-7, the long-chain quaternary ammonium salt is hydroxypropyl quaternary ammonium salt, the nucleating agent is PBAT, and the anti-hydrolysis agent is antioxidant 1010.

[0131] Example 7

[0132] Preparation of bio-based antibacterial materials

[0133] 1. Raw material composition: PLA 95 parts, antibacterial agent 5 parts, nucleating agent 1.5 parts, anti-hydrolysis agent 2 parts;

[0134] 2. Preparation steps:

[0135] (1) Preparation of antibacterial agent:

[0136] 1 g of zirconium hydrogen phosphate was added to 6 g of butylamine solution, and ultrasonic stirring was performed in a constant temperature water area of ​​50°C for 1.5 hours at an ultrasonic power of 3 kW. After cooling, the solution was centrifuged and the supernatant was removed to obtain a first precipitate, which was washed with anhydrous ethanol 5 times and dried in an oven at 60°C for 2 hours to obtain the product;

[0137] 1 g of the pre-product and 20 g of the long-chain quaternary ammonium salt were added to 20 ml of anhydrous ethanol respectively, and ultrasonically stirred for 2 hours in a constant temperature water area of ​​50°C with an ultrasonic power of 5 kW. After cooling, the mixture was centrifuged and the supernatant was removed to obtain a second precipitate, which was washed with anhydrous ethanol 5 times and dried in an oven at 60°C for 24 hours to obtain an antibacterial agent.

[0138] The antibacterial agent is a two-dimensional single-layer R4N@ZrP nanosheet with an aspect ratio of 630:1 and a specific surface area of ​​250m 2 / g.

[0139] (2) Preparation of the composite material:

[0140] First, the PLA was dried at 60°C for 6h, the PLA, nucleating agent, anti-hydrolysis agent were added into the high-speed mixer for pre-mixing, then the antibacterial agent was added for mixing and stirring, and then the melt blending was carried out at 180°C, 60rpm / min to prepare the composite particles, which could be molded by injection molding process;

[0141] The above PLA was 4032D produced by Nature Works, the zirconium hydrogen phosphate was CAS No. 13772-29-7, the long-chain quaternary ammonium salt was a heterocyclic quaternary ammonium salt, the nucleating agent was talc, and the anti-hydrolysis agent was antioxidant 1076.

[0142] Comparative Example 1

[0143] 1. Raw material composition: PLA 95 parts, antibacterial agent 5 parts;

[0144] 2. Preparation steps:

[0145] (1) Preparation of the antibacterial agent:

[0146] 1g of zirconium hydrogen phosphate was added to 8g of butylamine solution, and ultrasonic stirring was carried out in a 50°C constant temperature water bath for 1.5 hours, the ultrasonic power was 3kW, and after cooling, centrifugation was carried out, the supernatant was removed, and the first precipitate was obtained, which was washed with anhydrous ethanol for 5 times, and dried in a 60°C oven for 2 hours to obtain the product;

[0147] 1g of the pre-product and 20g of long-chain quaternary ammonium salt were added to 20ml of anhydrous ethanol, and ultrasonic stirring was carried out in a 50°C constant temperature water bath for 2 hours, the ultrasonic power was 5kw, and after cooling, centrifugation was carried out, the supernatant was removed, and the second precipitate was obtained, which was washed with anhydrous ethanol for 5 times, and placed in a 60°C oven for drying for 24 hours to obtain the antibacterial agent;

[0148] The above antibacterial agent was a two-dimensional monolayer R4N@ZrP nanosheet, the aspect ratio was 650:1, and the specific surface area was 260m 2 / g.

[0149] (2) Preparation of the composite material:

[0150] First, the PLA was dried at 60°C for 6h, the PLA was added into the high-speed mixer for pre-mixing, then the antibacterial agent was added for mixing and stirring, and then the melt blending was carried out at 180°C, 60rpm / min to prepare the composite particles, which could be molded by injection molding process;

[0151] The above PLA was 4032D produced by Nature Works, the zirconium hydrogen phosphate was CAS No. 13772-29-7, and the long-chain quaternary ammonium salt was cetyltrimethylammonium bromide.

[0152] Comparative Example 2

[0153] 1. Raw material composition: PLA 95 parts, zirconium hydrogen phosphate 5 parts, nucleating agent 1.5 parts, anti-hydrolysis agent 1.5 parts;

[0154] 2. Preparation steps:

[0155] First, dry the PLA at 60°C for 6h, add the PLA, nucleating agent, anti-hydrolysis agent into the high-speed mixer for pre-mixing, then add zirconium hydrogen phosphate for mixing and stirring, then melt blend at 180°C, 60rpm / min to prepare composite particles, which can be molded by injection molding process;

[0156] The above PLA is 4032D produced by Nature Works, zirconium hydrogen phosphate CAS No. 13772-29-7, long-chain quaternary ammonium salt is cetyltrimethylammonium bromide, nucleating agent is silicon dioxide, and anti-hydrolysis agent is inositol.

[0157] Comparative Example 3

[0158] 1. Raw material composition: PLA 100 parts;

[0159] 2. Preparation steps:

[0160] First, dry the PLA at 60°C for 6h, then melt at 180°C, 60rpm / min, which can be molded by injection molding process;

[0161] The above PLA is 4032D produced by Nature Works.

[0162] Comparative Example 4

[0163] 1. Raw material composition: PLA 95 parts, antibacterial agent 5 parts, nucleating agent 1.5 parts, anti-hydrolysis agent 1.5 parts;

[0164] 2. Preparation steps:

[0165] (1) Preparation of antibacterial agent:

[0166] Add 1g of zirconium hydrogen phosphate to 8g of butylamine solution in a 50°C constant temperature water bath for 1.5h, centrifuge after cooling, remove the supernatant, obtain the first precipitate, wash with anhydrous ethanol for 5 times, dry in a 60°C oven for 2h to obtain the product;

[0167] Add 1g of pre-product and 20g of long-chain quaternary ammonium salt to 20ml of anhydrous ethanol respectively, stir in a 50°C constant temperature water bath for 2h, centrifuge after cooling, remove the supernatant, obtain the second precipitate, wash with anhydrous ethanol for 5 times, place in a 60°C oven for drying for 24h to obtain the antibacterial agent;

[0168] The above antibacterial agent does not achieve effective intercalation, and the zirconium hydrogen phosphate still maintains the original structure, maintaining the aspect ratio (100:1) and specific surface area (50 nm / m 2 ) unchanged.

[0169] (2) Preparation of the composite material:

[0170] First, the PLA is dried at 60°C for 6h, the PLA, nucleating agent, anti-hydrolysis agent are added into a high-speed mixer for pre-mixing, then the antibacterial agent is added and mixed, and then melt blending is carried out at 180°C, 60 rpm / min to prepare composite particles, which can be molded by injection molding process;

[0171] The above PLA is 4032D produced by Nature Works, the zirconium hydrogen phosphate is CAS No. 13772-29-7, the long-chain quaternary ammonium salt is cetyltrimethylammonium bromide, the nucleating agent is silicon dioxide, and the anti-hydrolysis agent is inositol.

[0172] The performance test data of the above examples 1-7 and comparative examples 1-6 are shown in Table 1.

[0173] 1. Test methods and standards

[0174] 1.1 Antibacterial rate: QB / T 2591;

[0175] 1.2 Vicat softening point: GB / T 1633;

[0176] 1.4 Tensile strength (N / mm 2 ): GB / T 1040;

[0177] 1.5 Elongation at break (%): GB / T 1040.

[0178] 1.6 Aging performance: IEC 62506-2023 (85°C, 85% RH).

[0179] 2. Test results:

[0180] Table 1 Performance test table of examples and comparative examples

[0181]

[0182]

[0183] It can be found from Table 1 that the antibacterial effect of the application example is significantly higher than that of the comparative example, indicating that the specific surface area of the modified antibacterial agent (R4N@ZrP) is larger than that of zirconium hydrogen phosphate, the antibacterial effective contact area is larger, after the multi-layer structure is stripped into a single-layer structure, the aspect ratio is increased, and the nano effect is significant. Secondly, the heat resistance in the application example is better, indicating that the dispersibility of R4N@ZrP is better than that of zirconium hydrogen phosphate, and the compatibility of R4N@ZrP with the PLA resin matrix is better.

[0184] According to the principle of similar polarity, the organic-organic interface bonding force is greater than the organic-inorganic, Figure 4 The R4N@ZrP material and ZrP provided in the application example and the PLA matrix compatibility comparison chart. In addition, the mechanical properties in the application example are better, indicating that the R4N@ZrP with a higher specific surface area has a stronger interface bonding capacity with the PLA, effectively improves the stress conduction at the two-phase interface, and the heterogeneous nucleation effect, so that the strength and toughness are enhanced.

Claims

1. A bio-based antibacterial material, characterized in that: including polylactic acid, and antimicrobial agents; The antibacterial agent is a two-dimensional single-layer R4N@ZrP nanosheet, the aspect ratio of the two-dimensional single-layer R4N@ZrP nanosheet is greater than 600:1, and the specific surface area is greater than 240m 2 / g.

2. The bio-based antibacterial material according to claim 1, characterized in that: The two-dimensional single-layer R4N@ZrP nanosheet is prepared by modifying zirconium hydrogen phosphate ZrP with butylamine intercalation and then using long-chain quaternary ammonium salt R4N+ to enter the interlayer through ion exchange.

3. The bio-based antibacterial material according to claim 2, characterized in that: The bio-based antibacterial material further comprises a nucleating agent and an anti-hydrolysis agent.

4. The bio-based antibacterial material according to claim 3, characterized in that: The polylactic acid is a copolymer of left-handed polylactic acid and right-handed polylactic acid, and has a melt index of 1.5-10 g / min; The long-chain quaternary ammonium salt is one or more of cetyltrimethylammonium bromide, didodecyldimethylammonium bromide, benzyl quaternary ammonium salt, polyquaternary ammonium salt, hydroxypropyl quaternary ammonium salt and heterocyclic quaternary ammonium salt; The nucleating agent is one or more of PCL, PBS, PBAT, talc, silica, montmorillonite and organic carboxylates; The anti-hydrolysis agent is one or more of inositol, epoxy compounds, antioxidant 1010, antioxidant 1076, monocarbodiimide and polycarbodiimide.

5. The bio-based antibacterial material according to claim 3, characterized in that: In parts by weight, the bio-based antibacterial material includes 90-100 parts of polylactic acid, 0.5-10 parts of an antibacterial agent, 1-2 parts of a nucleating agent and 0.5-2 parts of an anti-hydrolysis agent.

6. The method for preparing the bio-based antibacterial material according to any one of claims 1 to 5, characterized in that: The method comprises the steps of preparing the antimicrobial agent; The preparation steps of the antibacterial agent include: Zirconium hydrogen phosphate was added to butylamine and ultrasonicated to obtain a pre-product; The pre-product is added into a long-chain quaternary ammonium salt solution and ultrasonicated to obtain an antibacterial agent.

7. The preparation method according to claim 6, characterized in that Adding zirconium hydrogen phosphate to butylamine, stirring ultrasonically at 50-70°C for 1-2 hours with an ultrasonic power of 2-4kW, then cooling and centrifuging to obtain a first precipitate, washing and drying to obtain a pre-product; The pre-product and the long-chain quaternary ammonium salt are added to anhydrous ethanol, ultrasonicated at 50-70° C. for 0.5-2.5 h with an ultrasonic power of 4-6 kW, and then cooled and centrifuged to obtain a second precipitate, which is washed and dried to obtain an antibacterial agent.

8. The preparation method according to claim 6, characterized in that The ratio of the added amounts of the zirconium hydrogen phosphate, butylamine, long-chain quaternary ammonium salt and anhydrous ethanol is 1g:1.5-8g:15-25g:5-15mL.

9. The preparation method according to claim 6, characterized in that Also included are a melt blending step and a shaping step, wherein: The melt blending step comprises: pre-mixing polylactic acid, a nucleating agent, and an anti-hydrolysis agent, then adding an antibacterial agent and mixing, and then melt blending to prepare composite particles; The molding step includes: molding the composite particles through extrusion or injection molding.

10. A refrigerator, characterized in that: The raw materials of the refrigerator include the bio-based antibacterial material according to any one of claims 1 to 5.

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