CN116041783A - Antibacterial and mildew-proof composition, antibacterial and mildew-proof polypropylene thermoplastic plastic and preparation method thereof - Google Patents

Abstract

The invention relates to a bacteriostatic and mildew-proof composition, bacteriostatic and mildew-proof polypropylene thermoplastic plastic and a preparation method thereof. The raw materials of the composition comprise inorganic nanometer mildew inhibitor and organic mildew inhibitor, wherein the weight ratio of the inorganic nanometer mildew inhibitor to the organic mildew inhibitor is (1-4): 1, and the preparation method comprises the following steps: and ball milling the inorganic nanometer mildew inhibitor, the organic mildew inhibitor and the color fixing coupling agent to obtain the antibacterial mildew-proof composition with the organic mildew inhibitor and the inorganic nanometer mildew inhibitor mutually coated. The antibacterial and mildew-proof polypropylene thermoplastic plastic comprises polypropylene resin, an antibacterial and mildew-proof composition and other additives, wherein the mass ratio of the polypropylene resin to the antibacterial and mildew-proof composition is (97-99.3) (0.3-1). Compared with the prior art, the antibacterial and mildew-proof polypropylene plastic has good heat resistance and mildew-proof performance, the mildew-proof plastic prepared at the processing temperature of more than 280 ℃ or higher has excellent stability and excellent antibacterial and antimicrobial properties, and the color of the plastic is hardly influenced.

Description

Antibacterial and mildew-proof composition, antibacterial and mildew-proof polypropylene thermoplastic plastic and preparation method thereof

Technical Field

The invention relates to the field of antibacterial and mildew-proof, in particular to an antibacterial and mildew-proof composition, antibacterial and mildew-proof polypropylene thermoplastic plastic and a preparation method thereof.

Background

Polypropylene plastic is widely applied, but in the using process of polypropylene plastic, mould is easy to generate due to migration of internal auxiliary agents, external pollution and the like, so that the use of polypropylene plastic products is influenced. In order to improve the mildew resistance of polypropylene plastic products, generally, a bacteriostatic mildew inhibitor is blended and added into polypropylene resin particles to prepare the polypropylene plastic products with the bacteriostatic mildew resistance.

The polyhexamethylene biguanide salt is a high molecular polymer, has small irritation, high sterilization speed and almost no toxicity, is safe and nontoxic to human bodies, and can not generate drug resistance to bacteria, thereby attracting attention. However, in polypropylene resins using polyhexamethylene biguanide additives, particularly when processed into fibers, the processing temperature is often higher than 280 ℃, and in the high-temperature process, polyhexamethylene biguanide salts are degraded due to insufficient thermal stability, so that the plastic is discolored, the mildew-proof effect is reduced or not, and the actual use is difficult, and meanwhile, the polyhexamethylene biguanide salts have good antibacterial effect on bacteria, but have the problem of poor inhibition effect on mold.

CN102453273B mentions that guanidine salt polymers generally have a low melting point, typically below 120 ℃, and the following problems easily occur when preparing master batches: (1) The guanidine salt polymer is easy to adhere to the wall in the mixer in the mixing stage, is not easy to uniformly mix with matrix resin and dispersing agent or other components, and is difficult to clean after adhering to the wall; (2) In the granulating stage, the guanidinium polymer has low melting point, is easy to absorb moisture, is easy to block in the feeding section of the screw, causes no blanking and can not be granulated, and the guanidinium polymer is easy to be stuck on the blanking funnel wall, is difficult to clean and causes the problem of inaccurate metering.

Disclosure of Invention

The invention aims to overcome at least one of the defects in the prior art and provide a bacteriostatic and mildew-proof composition, a bacteriostatic and mildew-proof polypropylene thermoplastic plastic and a preparation method thereof, wherein the bacteriostatic and mildew-proof composition has excellent stability and excellent antibacterial and antimicrobial properties, and the color of the plastic has little influence.

The aim of the invention can be achieved by the following technical scheme:

the inventor knows that the nano zinc oxide in the inorganic mildew preventive has large specific surface area, good heat resistance and mildew preventive performance superior to other metal inorganic matters, and is applied to mildew preventive scenes. However, the single use of nano zinc oxide can achieve good mildew-proof effect only by large addition amount of nano zinc oxide, and nano zinc oxide is easy to agglomerate, has poor dispersibility in polypropylene plastic, and cannot achieve mildew-proof effect.

Thiabendazole is another mildew-proof auxiliary agent used in organic mildew-proof agents in plastics, has high temperature resistance, wide sterilization spectrum, high speed and excellent mildew-proof effect, is widely applied to plastic modification as the mildew-proof auxiliary agent of plastics, but single thiabendazole cannot be effective to all moulds, and can cause the moulds to generate drug resistance to the thiabendazole after long-term use, so that a more effective antimicrobial strategy is needed, and the addition of other mildew-proof agents for compounding to resist the drug resistance of the moulds is an effective strategy, but the thiabendazole has the problem of poor antibacterial effect on bacteria.

The core-coating method is a common method for preparing an organic-inorganic composite material, and the main technology is an effective method for coating an organic material on a core of an inorganic compound by adopting a color fixing agent through a bonding effect or an adsorption effect through a mechanical method, an adsorption method and a corresponding improved technology to form new composite particles, so as to solve the problems of dispersibility of the inorganic material, stability and durability of the organic material, and based on the recognition, the following scheme is provided:

the inventor repeatedly research various methods for improving heat resistance, adopts a core-spun method, adopts gamma-aminopropyl triethoxysilane as a fixing agent, adopts nano zinc oxide and polyhexamethylene biguanide salt to carry out ball milling, prepares a composite mixed mildew preventive with the polyhexamethylene biguanide salt adsorbed on the surface of the nano zinc oxide and the surface of the polyhexamethylene biguanide salt adsorbed by the nano zinc oxide, and adds the prepared composite mildew preventive and thiabendazole into polymer resin after being mixed according to a certain proportion, and extrudes, melts and blends the mixture to prepare the polypropylene plastic with mildew preventive function. As a result, the mixed mildew preventive composition has good heat resistance and mildew resistance, and the mildew-proof plastic prepared at a processing temperature of more than 280 ℃ or higher has excellent stability and excellent antibacterial and antimicrobial properties, and the color of the plastic is hardly affected, specifically as follows:

the antibacterial and mildew-proof composition comprises the raw materials of an inorganic nanometer mildew inhibitor and an organic mildew inhibitor, wherein the weight ratio of the inorganic nanometer mildew inhibitor to the organic mildew inhibitor is (1-4): 1.

In the process of the nucleation, in order to enable the polyhexamethylene biguanide hydrochloride (PHMG) to be coated on the surface of nano zinc oxide or coated by nano zinc oxide (ZnO. NPS), the ratio of PHMG to ZnO is not higher than 4:1 and not lower than 1:1.

Further, the raw materials of the composition also comprise a fixation coupling agent, wherein the fixation coupling agent accounts for 0.5-1% of the total weight of the composition.

Further, the inorganic nanometer mildew preventive comprises nanometer zinc oxide, the organic mildew preventive comprises polyhexamethylene biguanide salt, and the fixation coupling agent comprises gamma-aminopropyl triethoxysilane.

The inventor knows that nano zinc oxide has 3 crystal structures in total, namely: hexagonal wurtzite structure, cubic sphalerite structure, and more rarely sodium chloride type octahedral structure, wurtzite and cubic sphalerite are regular tetrahedral structures with each zinc or oxygen atom and adjacent atoms forming a center around them, see fig. 2. Of the three structures, wurtzite is the most stable and common. The cubic zinc blende structure is obtained by generating ZnO on the surface of a crystal lattice under specific growth conditions. Therefore, the invention adopts the zinc oxide with easily obtained wurtzite structure as the inorganic antibacterial agent.

The nano zinc oxide has the advantages of small particles, high activity, large specific surface area, easy dispersion, high effectiveness, low heavy metal content and the like, and can chelate and crosslink with antibacterial groups by modifying the surface of the nano zinc oxide to increase the stability of the polyhexamethylene guanidine salt oligomer, as shown in figure 1. If only guanidine salt is used as an antibacterial agent, the guanidine salt can be decomposed when the processing temperature reaches 260 ℃, so that the base material is discolored, and the high temperature resistance of the compound is improved by combining the guanidine salt with nano zinc oxide, so that the discoloration of the material is avoided.

Further, the polyhexamethylene biguanide salt is an oligomer of polyhexamethylene biguanide salt, the softening point temperature is lower than 70 ℃, and the diameter of the nano zinc oxide is 30-100nm.

A preparation method of the antibacterial and mildew-proof composition comprises the following steps: and ball milling the inorganic nanometer mildew inhibitor, the organic mildew inhibitor and the color fixing coupling agent to obtain the antibacterial mildew-proof composition with the organic mildew inhibitor and the inorganic nanometer mildew inhibitor mutually coated.

The invention utilizes the characteristic of low melting point of polyhexamethylene guanidine salt and the characteristic of a process of energy storage and heat generation of high-energy ball milling; in the ball milling process, the surface of the nano zinc oxide is heated, the powder activity is greatly improved, meanwhile, the surface of the polyhexamethylene guanidine salt is more easily melted due to friction heat generated by ball milling, the melted polyhexamethylene guanidine salt is easily adhered to the surface of the nano zinc oxide, and the compound antibacterial agent formed by mutually coating the polyhexamethylene guanidine salt and the nano zinc oxide is formed in the mixing process.

Further, the rotation speed of the ball milling is 100-300r/min, and the time is 1-2h.

The antibacterial and mildew-proof polypropylene thermoplastic plastic comprises polypropylene resin, the antibacterial and mildew-proof composition and thiabendazole, wherein the mass ratio of the polypropylene resin to the antibacterial and mildew-proof composition to the thiabendazole is (97-99.3) (0.3-1).

Further, the plastic comprises the following components in parts by mass: 97-99.3 parts of polypropylene resin; 0.3-1 part of antibacterial and mildew-proof composition; 0.3-1 part of thiabendazole; thiabendazole is white powder with purity higher than 98%. 0.1-1 part of stearate.

The preparation method of the antibacterial mildew-proof polypropylene thermoplastic plastic comprises the following steps: and mixing the polypropylene resin, the antibacterial and mildew-proof composition and other additives, and performing melt blending, extrusion granulation and drying to obtain the antibacterial and mildew-proof polypropylene thermoplastic plastic.

Further, the temperature of the extrusion granulation is 190-220 ℃, and the rotating speed is 300-400rpm; the drying temperature is 100-110 ℃ and the drying time is 0.5-2h.

Compared with the prior art, the invention has the following advantages:

(1) The invention skillfully adopts the heat generated in the ball milling process to melt the polyhexamethylene guanidine hydrochloride oligomer, the surface of the nano zinc oxide is activated in the ball milling process, and the ball milling simultaneously causes the surface of the polyhexamethylene guanidine hydrochloride oligomer to melt, so that the melted oligomer is easily coated on the nano zinc oxide inorganic particles. The addition of the coupling color fixing agent and the ball milling can lead the guanidine salt oligomer and zinc oxide to have bonding action, further increase the bonding strength of the guanidine salt oligomer and zinc oxide, and the specific bonding mechanism is shown in figure 2. Meanwhile, the polyhexamethylene biguanide salt prepared by the core-spun method is adsorbed on the nano zinc oxide, so that the problems of sticking and agglomeration in the blanking process are solved, and the heat resistance of the polyhexamethylene biguanide salt is improved;

(2) The invention adopts Thiabendazole (TBZ) and the composite antibacterial agent prepared by the nucleation method for adsorbing the polyhexamethylene biguanide salt on the nano zinc oxide to be used together, wherein the TBZ has the characteristics of wide sterilization spectrum, high speed and excellent mildew-proof effect, and the composite antibacterial agent prepared by the nucleation method for adsorbing the polyhexamethylene biguanide salt on the nano zinc oxide solves the problems of unsmooth blanking of the polyhexamethylene biguanide salt, poor high-temperature processing temperature resistance and easy discoloration, and the obtained composite antibacterial material combines the characteristics of good antibacterial performance of guanidine salt, good mildew-proof performance of TBZ and good antibacterial mildew-proof effect.

Drawings

FIG. 1 is a schematic view of the surface modification principle of zinc oxide;

fig. 2 is a diagram showing two structural configurations of zinc oxide.

Detailed Description

The invention will now be described in detail with reference to the drawings and specific examples. The present embodiment is implemented on the premise of the technical scheme of the present invention, and a detailed implementation manner and a specific operation process are provided, but the protection scope of the present invention is not limited to the following embodiments.

The polyhexamethylene guanidine salt coated nano zinc oxide composite mildew preventive is prepared by the following method:

adding nano zinc oxide powder, polyhexamethylene biguanide hydrochloride and gamma-aminopropyl triethoxysilane into a ball milling tank according to a set proportion, setting the rotating speed to be 100-300r/min, ball milling for 1-2h, and taking out to obtain a mildew-proof composition coated with polyhexamethylene biguanide hydrochloride (PHMG) and nano zinc oxide; the diameter of the nano zinc oxide is 30-100nm; the polyhexamethylene biguanide salt is an oligomer of polyhexamethylene biguanide salt, and the softening point temperature of the polyhexamethylene biguanide salt is lower than 70 ℃; the weight ratio of the nano zinc oxide to the polyhexamethylene biguanide salt is (1-4) 1; gamma-aminopropyl triethoxy silane is used as a fixation coupling agent; the weight ratio of the gamma-aminopropyl triethoxysilane is 0.5-1% of the total weight;

a bacteriostatic and mildew-proof polypropylene thermoplastic plastic comprises 97-99.3 parts of polypropylene resin; 0.3-1 part of composite mildew inhibitor of polyhexamethylene biguanide salt adsorbed on the surface of nano zinc oxide. 0.3-1 part of thiabendazole; and 0.1-1 part of stearate, and the preparation method comprises the following steps: providing a mixture of a compound mildew preventive and thiabendazole, wherein the compound mildew preventive comprises polypropylene resin and polyhexamethylene biguanide salt adsorbed on the surface of nano zinc oxide, and stearate; and (3) melting and blending the mixture, extruding and granulating to obtain the antibacterial and mildew-proof polypropylene plastic.

The raw material sources are as follows:

polyhexamethylene biguanide hydrochloride oligomer (PHMG): the softening point temperature of Tianjin Kochia Miao environmental protection technology Co., ltd is 60 DEG C

Nanoscale zinc oxide: hangzhou intelligent titanium purification technology Co.Ltd

Gamma-aminopropyl triethoxysilane (KH 550): shandong silicon materials Co.Ltd

Thiabendazole: purity 99%, white powder, xuzhou shenlong chemical Co., ltd

Polypropylene: brand 7726, yanshan petrochemical industry

And (3) testing mildew resistance:

the sample to be detected is sterilized with 75% ethanol and dried, and placed in a surface dish containing nutrient salt culture medium, six mold spore suspensions of Aspergillus niger, aspergillus terreus, paecilomyces variotii, penicillium funiculosum, aureobasidium pullulans and Chaetomium globosum with concentration of (1X 106+/-2X 105) spores/mL are prepared, and are uniformly sprayed on the culture medium and the surface of the sample, and are cultured for 28d under the conditions of the temperature of 28 ℃ and the relative humidity of more than 90%RH, and the mold growth condition is observed and recorded.

Evaluation of results: the sample is taken out and is observed immediately, and the mould growth area of the blank control sample A is not less than 10%, otherwise, the blank control sample A cannot be used as the blank control sample of the test.

Sample mould growth grade assessment:

level 0: not long, i.e. no growth was seen under microscope (50 times magnification);

stage l: trace growth, i.e., macroscopic growth, but with a growth footprint of less than 10%;

2 stages: the growth coverage area is less than 30% but not less than 10% (light growth);

3 stages: the growth coverage area is less than 60%, but not less than 30% (moderate growth);

4 stages: the growth coverage area is greater than 60% to full coverage (severe growth).

Preparation of polyhexamethylene biguanide salt coated nano zinc oxide material

Example 1

Adding nano zinc oxide powder, polyhexamethylene biguanide hydrochloride and gamma-aminopropyl triethoxysilane into a ball milling tank according to the mass ratio of 1:1:0.01, setting the rotating speed to be 200r/min, ball milling for 1h, and taking out to obtain the polyhexamethylene biguanide hydrochloride (PHMG) coated nano zinc oxide mildew-proof composition A.

Example 2

Adding nano zinc oxide powder, polyhexamethylene biguanide hydrochloride and gamma-aminopropyl triethoxysilane into a ball milling tank according to the mass ratio of 1:4:0.01, setting the rotating speed to be 200r/min, ball milling for 1h, and taking out to obtain the polyhexamethylene biguanide hydrochloride (PHMG) coated nano zinc oxide mildew-proof composition B.

Comparative example 1

Adding nano zinc oxide powder and gamma-aminopropyl triethoxysilane into a ball milling tank according to the mass ratio of 1:0.01, setting the rotating speed to be 200r/min, ball milling for 1h, and taking out to obtain the nano zinc oxide mildew-proof composition C.

Comparative example 2

And adding the polyhexamethylene biguanidine hydrochloride and gamma-aminopropyl triethoxysilane into a ball milling tank according to the mass ratio of 1:0.01, setting the rotating speed to be 200r/min, ball milling for 1h, and taking out to obtain the polyhexamethylene biguanidine hydrochloride (PHMG) mildew resistant composition D.

Comparative examples 2 to 2

Adding nano zinc oxide powder and polyhexamethylene biguanide hydrochloride into a ball milling tank according to a mass ratio of 1:4, setting the rotating speed to be 200r/min, ball milling for 1h, and taking out to obtain the polyhexamethylene biguanide hydrochloride (PHMG) coated nano zinc oxide mildew-proof composition E.

Preparation of mildew-proof polypropylene thermoplastic

Example 3

Placing 98.4 parts by weight of polypropylene, 0.3 part by weight of mildew inhibitor A,0.3 part by weight of thiabendazole, 0.3 part by weight of calcium stearate and 1.0 part by weight of the mixture into a high-speed mixer for fully and uniformly stirring, then melt-blending the mixture by a double-screw extruder, extruding and granulating at the temperature of 190-220 ℃ at the rotating speed of 350r.p.m, drying the extruded granules in a constant-temperature oven at 105 ℃ for 1h,

then, the mixture was injected into a sample of 50 mm. Times.50 mm. Times.2 mm at an injection temperature of 200-220℃to conduct a mold-proofing property test. The results of the test for mildew resistance are reported in table 1. The sample was left at 280℃for 3-5min, the surface colour of the article was observed and the observations are recorded in Table 1:

example 5

Placing 98.4 parts by weight of polypropylene, 0.3 part by weight of mildew inhibitor B,0.3 part by weight of thiabendazole, 0.3 part by weight of calcium stearate and 1.0 part by weight of calcium stearate into a high-speed mixer, fully and uniformly stirring, then melt-blending the mixed materials through a double-screw extruder, extruding and granulating at the temperature of 190-220 ℃ at the rotating speed of 350r.p.m, drying the extruded granules in a constant-temperature oven at 105 ℃ for 1h,

then, the mixture was injected into a sample of 50 mm. Times.50 mm. Times.2 mm at an injection temperature of 200-220℃to conduct a mold-proofing property test. The results of the test for mildew resistance are reported in table 1. The sample was left at 280℃for 3-5min, the surface colour of the article was observed and the observations are recorded in Table 1:

comparative example 5

And (3) putting 98.4 parts by weight of polypropylene, 0.3 part by weight of thiabendazole, 0.15 part by weight of PHMG, 0.15 part by weight of nano zinc oxide, 0.15 part by weight of calcium stearate and 1.0 part by weight of calcium stearate into a high-speed mixer, fully and uniformly stirring, then carrying out melt blending on the mixed materials through a double-screw extruder, extruding and granulating at 190-220 ℃ at 350r.p.m, drying the extruded granules in a constant-temperature oven at 105 ℃ for 1h, and then injecting the granules into a sample with 50mm multiplied by 2mm at the injection molding temperature of 200-220 ℃, thereby carrying out mildew resistance test. The test mildew resistance results are reported in table 2. The sample was left at 280℃for 3-5min, the surface colour of the article was observed and the observations are recorded in Table 2:

example 4

Putting 97.7 parts by weight of polypropylene, 1 part by weight of mildew inhibitor A,0.3 part by weight of thiabendazole, 0.0 part by weight of calcium stearate and 1.0 part by weight of the mildew inhibitor A into a vibration mixer for fully and uniformly stirring, then melt-blending the mixed materials through a double-screw extruder, extruding and granulating at the temperature of 190-220 ℃ and the rotating speed of 350r.p.m, drying the extruded granules in a constant-temperature oven at 105 ℃ for 1h,

then injecting the mixture into a sample with the thickness of 50mm multiplied by 2mm at the injection temperature of 200-220 ℃ for antibacterial and mildew-proof performance test. The results of the antibacterial and mildew-proof properties tested are recorded in table 1. The extruded pellets were placed in a crucible and then at 280℃for 3-5min, the surface colour of the article was removed and the observations recorded in Table 1:

example 6

Putting 97.7 parts by weight of polypropylene, 1.0 part by weight of mildew inhibitor B,0.3 part by weight of thiabendazole, 0.0 part by weight of calcium stearate and 1.0 part by weight of the mixture into a high-speed mixer for fully and uniformly stirring, then melt-blending the mixture by a double-screw extruder, extruding and granulating at the temperature of 190-220 ℃ at the rotating speed of 350r.p.m, drying the extruded granules in a constant-temperature oven at 105 ℃ for 1h,

then, the mixture was injected into a sample of 50 mm. Times.50 mm. Times.2 mm at an injection temperature of 200-220℃to conduct a mold-proofing property test. The results of the test for mildew resistance are reported in table 1. The sample was left at 280℃for 3-5min, the surface colour of the article was observed and the observations are recorded in Table 1:

comparative example 3

And (3) putting 97.7 parts by weight of polypropylene, 1.0 part by weight of mildew preventive C, 0.3 part by weight of thiabendazole, 0.3 part by weight of calcium stearate and 1.0 part by weight of the mixture into a vibration mixer for fully and uniformly stirring, then carrying out melt blending on the mixture by a double-screw extruder, extruding and granulating at the extruder temperature of 190-220 ℃ and the rotating speed of 350r.p.m, drying the extruded granules in a constant-temperature oven at 105 ℃ for 1h, and then injecting the granules into a sample with the injection temperature of 200-220 ℃ of 50mm multiplied by 2mm, so as to carry out antibacterial and mildew-proof performance test. The results of the antibacterial and mildew-proof properties tested are recorded in table 2. The extruded pellets were placed in a crucible and then at 280℃for 3-5min, the surface colour of the article was removed and the observations recorded in Table 2:

comparative example 4

And (3) putting 97.7 parts by weight of polypropylene, 1.0 part by weight of mildew preventive D, 0.3 part by weight of thiabendazole, 0.3 part by weight of calcium stearate and 1.0 part by weight of the mixture into a vibration mixer for fully and uniformly stirring, then carrying out melt blending on the mixture by a double-screw extruder, extruding and granulating at the extruder temperature of 190-220 ℃ and the rotating speed of 350r.p.m, drying the extruded granules in a constant-temperature oven at 105 ℃ for 1h, and then injecting the granules into a sample with the injection temperature of 200-220 ℃ of 50mm multiplied by 2mm, so as to carry out antibacterial and mildew-proof performance test. The test mildew resistance results are reported in table 2. The extruded pellets were placed in a crucible and then at 280℃for 3-5min, the surface colour of the article was removed and the observations recorded in Table 2:

comparative example 6

The preparation method comprises the steps of putting 97.7 parts by weight of polypropylene, 0.3 part by weight of thiabendazole, 0.8 part by weight of PHMG, 0.2 part by weight of nano zinc oxide, 1.0 part by weight of calcium stearate into a high-speed mixer, fully and uniformly stirring, then melt-blending the mixed materials through a double-screw extruder, extruding and granulating at 190-220 ℃ at 350r.p.m, drying the extruded granules in a constant-temperature oven at 105 ℃ for 1h, and then injecting the dried granules into a sample with 50mm multiplied by 2mm at the injection molding temperature of 200-220 ℃, thereby carrying out a mildew resistance test. The test mildew resistance results are reported in table 2. The sample was left at 280℃for 3-5min, the surface colour of the article was observed and the observations are recorded in Table 2:

example 7

Putting 97.0 parts by weight of polypropylene, 1.0 part by weight of mildew inhibitor B,1.0 part by weight of thiabendazole, 1.0 part by weight of calcium stearate and 1.0 part by weight of the mixture into a high-speed mixer for fully and uniformly stirring, then melt-blending the mixture by a double-screw extruder, extruding and granulating at the temperature of 190-220 ℃ at the rotating speed of 350r.p.m, drying the extruded granules in a constant-temperature oven at 105 ℃ for 1h,

then, the mixture was injected into a sample of 50 mm. Times.50 mm. Times.2 mm at an injection temperature of 200-220℃to conduct a mold-proofing property test. The results of the test for mildew resistance are reported in table 1. The sample was left at 280℃for 3-5min, the surface colour of the article was observed and the observations are recorded in Table 1:

comparative example 7

And (3) putting 98.0 parts by weight of polypropylene, 1.0 part by weight of mildew preventive A,1.0 part by weight of calcium stearate and 1.0 part by weight of the mildew preventive A into a vibration mixer for fully mixing, then carrying out melt blending on the mixed materials through a double-screw extruder, extruding and granulating at the extruder temperature of 190-220 ℃ and the rotating speed of 350r.p.m, drying the extruded granules in a constant-temperature oven at 105 ℃ for 1h, and then injecting the granules into a sample with the injection temperature of 200-220 ℃ of 50mm multiplied by 2mm, thereby carrying out antibacterial and mildew-proof performance test. The results of the antibacterial and mildew-proof properties tested are recorded in table 2. The extruded pellets were placed in a crucible and then at 280℃for 3-5min, the surface colour of the article was removed and the observations recorded in Table 2:

comparative example 8

And (3) putting 98.0 parts by weight of polypropylene, 1.0 part by weight of mildew preventive B,1.0 part by weight of calcium stearate and 1.0 part by weight of the mildew preventive B into a vibration mixer for fully mixing, then carrying out melt blending on the mixed materials through a double-screw extruder, extruding and granulating at the extruder temperature of 190-220 ℃ and the rotating speed of 350r.p.m, drying the extruded granules in a constant-temperature oven at 105 ℃ for 1h, and then injecting the granules into a sample with the injection temperature of 200-220 ℃ of 50mm multiplied by 2mm, thereby carrying out antibacterial and mildew-proof performance test. The results of the antibacterial and mildew-proof properties tested are recorded in table 2. The extruded pellets were placed in a crucible and then at 280℃for 3-5min, the surface colour of the article was removed and the observations recorded in Table 2:

comparative example 9

And (3) putting 98.0 parts by weight of polypropylene, 1.0 part by weight of mildew preventive E,1.0 part by weight of calcium stearate and 1.0 part by weight of the mildew preventive E into a vibration mixer for fully mixing, then carrying out melt blending on the mixed materials through a double-screw extruder, extruding and granulating at the extruder temperature of 190-220 ℃ and the rotating speed of 350r.p.m, drying the extruded granules in a constant-temperature oven at 105 ℃ for 1h, and then injecting the granules into a sample with the injection temperature of 200-220 ℃ of 50mm multiplied by 2mm, thereby carrying out antibacterial and mildew-proof performance test. The results of the antibacterial and mildew-proof properties tested are recorded in table 2. The extruded pellets were placed in a crucible and then at 280℃for 3-5min, the surface colour of the article was removed and the observations recorded in Table 2:

TABLE 1

TABLE 2

As can be seen from tables 1-2, in example 3, example 4 is compared with comparative example 5 and comparative example 6, after the nucleation method is adopted, PHMG has no discoloration and degradation in processing, antibacterial performance in the example is well maintained and improved, and in example 4, example 6 is compared with comparative example 3 and comparative example 4, it is shown that antibacterial performance of the composite material is improved after nano zinc oxide powder and polyhexamethylene biguanide hydrochloride are added simultaneously; as can be seen from examples 7 and comparative examples 7-8, thiabendazole improves the mildew resistance of the composite; example 6 and comparative example 9, it is known that the addition of the fixing agent increases the yellowing resistance of the material. Therefore, after the composite antibacterial agent is adopted, the problem that the blanking opening is blocked due to the fact that PHMG is singly added and is easy to adhere to the blanking opening is solved, and meanwhile, the composite antibacterial mildew preventive also has good mildew resistance.

In summary, it is known that the antibacterial and mildew-proof polypropylene plastic of the present invention has good heat resistance and mildew-proof properties, and that the mildew-proof plastic prepared at a processing temperature of more than 280 ℃ or higher has excellent stability and excellent antibacterial and antimicrobial properties, and the color of the plastic is hardly affected.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the invention in any way, and any person skilled in the art may make modifications or alterations to the disclosed technical content to the equivalent embodiments. However, any simple modification, equivalent variation and variation of the above embodiments according to the technical substance of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims (10)

1. A bacteriostatic and mildew-proof composition is characterized in that the raw materials of the composition comprise an inorganic nanometer mildew inhibitor and an organic mildew inhibitor, wherein the weight ratio of the inorganic nanometer mildew inhibitor to the organic mildew inhibitor is (1-4): 1.

2. The bacteriostatic and mildewproof composition according to claim 1, wherein the raw materials of the composition further comprise a fixation coupling agent, wherein the fixation coupling agent accounts for 0.5-1% of the total weight of the composition.

3. The bacteriostatic and mildewproof composition of claim 1, wherein said inorganic nano mildewproof agent comprises nano zinc oxide, said organic mildewproof agent comprises polyhexamethylene biguanide salt, and said color fixing coupling agent comprises gamma-aminopropyl triethoxysilane.

4. A bacteriostatic and mildewproof composition according to claim 3 wherein said polyhexamethylene biguanide salt is an oligomer of polyhexamethylene biguanide salt having a softening point temperature below 70 ℃ and a diameter of 30-100nm.

5. A method of preparing a bacteriostatic and mildewproof composition as claimed in any one of claims 1 to 4 which comprises: and ball milling the inorganic nanometer mildew inhibitor, the organic mildew inhibitor and the color fixing coupling agent to obtain the antibacterial mildew-proof composition with the organic mildew inhibitor and the inorganic nanometer mildew inhibitor mutually coated.

6. The method for preparing the antibacterial and mildew-proof composition according to claim 5, wherein the rotation speed of the ball mill is 100-300r/min, and the time is 1-2h.

7. A bacteriostatic and mildewproof polypropylene thermoplastic plastic, which comprises a polypropylene resin, a bacteriostatic and mildewproof composition as defined in any one of claims 1 to 4 and thiabendazole, wherein the mass ratio of the polypropylene resin to the bacteriostatic and mildewproof composition to the thiabendazole is (97 to 99.3): 0.3 to 1: (0.3 to 1).

8. The antibacterial and mildew-proof polypropylene thermoplastic plastic according to claim 7, wherein the plastic comprises the following components in parts by mass:

9. a method for preparing the antibacterial and mildew-proof polypropylene thermoplastic plastic as claimed in claim 7 or 8, which is characterized in that the method comprises the following steps: and mixing the polypropylene resin, the antibacterial and mildew-proof composition and other additives, and performing melt blending, extrusion granulation and drying to obtain the antibacterial and mildew-proof polypropylene thermoplastic plastic.

10. The method for preparing the antibacterial and mildew-proof polypropylene thermoplastic according to claim 9, wherein the extrusion granulating temperature is 190-220 ℃ and the rotating speed is 300-400rpm; the drying temperature is 100-110 ℃ and the drying time is 0.5-2h.

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