CN115109342B

CN115109342B - Polypropylene plastic and preparation method thereof

Info

Publication number: CN115109342B
Application number: CN202210819726.2A
Authority: CN
Inventors: 胡定军; 刘朝军; 肖艺
Original assignee: Zhejiang Jinhai High Tech Co ltd
Current assignee: Zhejiang Jinhai High Tech Co ltd
Priority date: 2022-07-13
Filing date: 2022-07-13
Publication date: 2024-04-30
Anticipated expiration: 2042-07-13
Also published as: CN115109342A

Abstract

The invention relates to polypropylene plastic and a preparation method thereof. The polypropylene plastic comprises the following components in parts by weight: 85-94 parts of polypropylene resin, 1-5 parts of antibacterial agent and 5-10 parts of PDMS surface modified diatomite. According to the polypropylene plastic, an antibacterial agent is added, and Polydimethylsiloxane (PDMS) surface modified diatomite is adopted for blending modification, so that the surface tension of the polypropylene plastic can be reduced, and meanwhile, the modified polypropylene plastic has an excellent antibacterial and mildew-proof effect.

Description

Polypropylene plastic and preparation method thereof

Technical Field

The invention relates to the field of polypropylene composite materials, in particular to polypropylene plastic and a preparation method thereof.

Background

Polypropylene is one of the most important general engineering plastics, and is widely applied to industries such as automobiles, household appliances, kitchens and bathrooms, clothing, medical appliances, fiber products and the like due to the advantages of good mechanical properties, excellent chemical corrosion resistance, low price and the like. However, in long-term use, harmful microorganisms such as bacteria and mold are easy to grow on the surface of the polypropylene plastic, so that safety and sanitation problems can be generated in the use process of consumers, the polypropylene plastic needs to be subjected to antibacterial modification, and the growth of the harmful microorganisms on the surface of the polypropylene plastic can be inhibited by introducing an antibacterial agent.

The antibacterial agents commonly used for antibacterial modification of polypropylene plastics are inorganic antibacterial agents such as Ag ions and salt compounds thereof, organic antibacterial agents, natural antibacterial agents and the like, but in long-term use, the polypropylene antibacterial plastics can be polluted by dust, impurities, oil and the like existing in the air, meanwhile, bacteria killed on the surface of the polypropylene antibacterial plastics can be deposited on the surface of the antibacterial materials to generate bacterial plaques, so that the efficiency of the antibacterial materials is reduced and the antibacterial materials are attenuated.

Accordingly, there is a need to provide a novel polypropylene plastic and a method for preparing the same.

Disclosure of Invention

In order to solve the defects in the prior art, the invention provides the polypropylene plastic which has low surface tension and excellent antibacterial and mildew-proof effects.

In one aspect, the present invention provides a polypropylene plastic comprising, by weight of the polypropylene plastic:

(1) 85-94 parts of polypropylene resin;

(2) 1 to 5 parts of an antibacterial agent; and

(3) 5-10 Parts of PDMS surface modified diatomite.

In an embodiment of the invention, the antimicrobial agent is a monoatomic antimicrobial agent; the monoatomic antibacterial agent comprises a carrier and a transition metal, wherein the carrier is selected from one or more of titanium dioxide, diatomite, calcium carbonate, kaolin, aluminum oxide and zeolite molecular sieves, and the transition metal is selected from one or more of iron, cobalt, nickel, copper, zinc, silver and manganese; preferably, the transition metal is selected from one or more of copper, zinc and silver.

In an embodiment of the present invention, the polypropylene plastic further comprises, based on the weight of the polypropylene plastic:

(4) 0.1 to 0.5 parts of stearate.

In an embodiment of the invention, the diatomaceous earth has a weight average particle size of from 5 to 30 microns.

In an embodiment of the invention, the polypropylene plastic is substantially free of any fluorine-containing compounds.

In another aspect, the present invention also provides a method for preparing the polypropylene plastic, the method comprising:

(1) Providing a mixture comprising a polypropylene resin, an antimicrobial agent, diatomaceous earth, and a stearate;

(2) The mixture is melt extruded to form a polypropylene plastic.

In an embodiment of the invention, the antimicrobial agent is a monoatomic antimicrobial agent;

The monoatomic antibacterial agent comprises a carrier and a transition metal, wherein the carrier is selected from one or more of titanium dioxide, diatomite, calcium carbonate, kaolin, aluminum oxide and zeolite molecular sieves, and the transition metal is selected from one or more of iron, cobalt, nickel, copper, zinc, silver and manganese;

Preferably, the transition metal is selected from one or more of copper, zinc and silver.

In an embodiment of the invention, the method further comprises: adding a silane coupling agent into the diatomite, and mixing; adding PDMS, and mixing to form PDMS surface modified diatomite;

Preferably, the silane coupling agent is an amino-functional silane coupling agent.

In an embodiment of the invention, the method does not include any step of adding a fluorochemical.

In the invention, by adding diatomite, especially PDMS surface modified diatomite, to the polypropylene resin in a melt blending mode, the surface tension of the polypropylene plastic can be reduced, thereby reducing and lowering dust, impurities and microorganisms adhered to the surface of the polypropylene plastic. Meanwhile, the diatomite with the modified PDMS surface can be cooperated with a single-atom antibacterial agent, so that the mildew-proof effect of the polypropylene plastic is further improved. Moreover, the diatomite with the modified PDMS surface does not influence the antibacterial effect of the monoatomic antibacterial agent, has good antibacterial performance on candida albicans, escherichia coli and staphylococcus aureus, and the antibacterial rate can reach more than 99%. In the invention, the heavy metal content in the polypropylene material prepared by adopting the monoatomic metal antibacterial agent is far lower than the minimum standard of the industry, so that the application safety of the polypropylene plastic is greatly improved, and the polypropylene material has wide application prospect.

Detailed Description

These and other features and advantages of the present invention will become apparent from a reading of the following detailed description. It is to be understood that both the foregoing general description and the following detailed description are explanatory only and are not restrictive of aspects as claimed.

The various ranges disclosed herein are defined as lower and upper limits, with the given range being defined by the selection of a lower and upper limit, which define the boundaries of the particular range. Ranges that are defined in this way can be inclusive or exclusive of the endpoints, and any combination can be made, i.e., any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a particular parameter, it is understood that ranges of 60-110 and 80-120 are also contemplated. Furthermore, if the minimum range values 1 and 2 are listed, and if the maximum range values 3,4 and 5 are listed, the following ranges are all contemplated: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In the present application, unless otherwise indicated, the numerical range "a-b" represents a shorthand representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" have been listed throughout, and "0-5" is simply a shorthand representation of a combination of these values. When a certain parameter is expressed as an integer of 2 or more, it is disclosed that the parameter is, for example, an integer of 2, 3,4, 5, 6, 7, 8, 9,10, 11, 12 or the like.

In the present application, all the embodiments mentioned herein and the preferred embodiments may be combined with each other to form new technical solutions, if not specifically described. In the present application, all technical features mentioned herein and preferred features may be combined with each other to form new technical solutions, if not specifically stated.

In the present application, the terms "comprising" and "including" as used herein mean open-ended or closed-ended, unless otherwise noted. For example, the terms "comprising" and "comprises" may mean that other components not listed may be included or included, or that only listed components may be included or included.

In the description herein, unless otherwise indicated, the term "or" is inclusive. For example, the phrase "a or B" means "a, B, or both a and B. More specifically, either of the following conditions satisfies the condition "a or B": a is true (or present) and B is false (or absent); a is false (or absent) and B is true (or present); or both A and B are true (or present).

In the present invention, in order to reduce the surface contamination of polypropylene plastics, it is generally required that the polypropylene plastic surface has a certain repellency to dust, impurities and various aerosols in the air, particularly, water aerosols, oil aerosols. For this reason, the inventors have studied to find that by adding diatomaceous earth, particularly Polydimethylsiloxane (PDMS) surface-modified diatomaceous earth, to polypropylene resin in a melt blending manner, the surface tension of polypropylene plastic can be greatly reduced, thereby reducing and lessening the adhesion ability of dust, impurities and aerosols to the surface of polypropylene plastic. Meanwhile, as the PDMS is friendly to the environment, the PDMS is harmless to human bodies, and the harm to the environment is reduced.

In the invention, the polypropylene plastic comprises 85-94 parts, 88-94 parts, 90-94 parts, 92-94 parts, 85-92 parts, 88-92 parts, 90-92 parts, 85-90 parts, 88-90 parts or 85-88 parts of polypropylene resin according to the weight parts of the polypropylene plastic. In the present invention, the polypropylene resin may be subjected to various modifications in advance, for example, chemical modification (e.g., copolymerization modification, graft modification, crosslinking modification, etc.) and physical modification (e.g., filling modification, blending modification, reinforcement modification, etc.).

In the invention, the polypropylene plastic comprises 1 to 5 parts, 1 to 4 parts, 1 to 3 parts, 1 to 2 parts, 2 to 5 parts, 2 to 4 parts, 2 to 3 parts, 3 to 5 parts, 3 to 4 parts or 4 to 5 parts of antibacterial agent by weight of the polypropylene plastic. In the present invention, the antibacterial agent may be an inorganic antibacterial agent, for example, a monoatomic antibacterial agent; the monoatomic antibacterial agent comprises a carrier and a transition metal, wherein the carrier is selected from one or more of titanium dioxide, diatomite, calcium carbonate, kaolin, aluminum oxide and zeolite molecular sieves, and the transition metal is selected from one or more of iron, cobalt, nickel, copper, zinc, silver and manganese; preferably, the transition metal is selected from one or more of copper, zinc and silver. In specific embodiments, the transition metal to carrier mass ratio of the monoatomic antimicrobial agent is 1:10-1:100, 1:10-1:60, 1:10-1:20, 1:20-1:100, or 1:20-1:60.

In the invention, the polypropylene plastic comprises 5 to 10 parts, 5 to 9 parts, 5 to 8 parts, 5 to 7 parts, 5 to 6 parts, 6 to 10 parts, 6 to 9 parts, 6 to 8 parts, 6 to 7 parts, 7 to 10 parts, 7 to 9 parts, 7 to 8 parts, 8 to 10 parts, 8 to 9 parts or 9 to 10 parts of diatomite by weight of the polypropylene plastic. In the present invention, the diatomaceous earth may be one or more selected from natural diatomaceous earth, inorganic modified diatomaceous earth, and organic modified diatomaceous earth. As a preferred embodiment of the present invention, the diatomaceous earth may be Polydimethylsiloxane (PDMS) surface-modified diatomaceous earth. In some embodiments, the diatomaceous earth of the present invention may have a weight average particle size ranging from 5 to 30 microns, from 5 to 25 microns, from 5 to 20 microns, from 5 to 15 microns, or from 5 to 10 microns.

In the invention, the polypropylene plastic comprises 0.1 to 0.5 part, 0.1 to 0.4 part, 0.1 to 0.3 part, 0.1 to 0.2 part, 0.2 to 0.5 part, 0.2 to 0.4 part, 0.2 to 0.3 part, 0.3 to 0.5 part, 0.3 to 0.4 part or 0.4 to 0.5 part of stearate based on the weight of the polypropylene plastic. In the invention, the stearate is used as a dispersing agent in the melt blending polypropylene resin to effectively disperse the raw materials of all substances, improve the uniformity of materials and fully reduce the surface tension of polypropylene plastics. In some embodiments, the stearate is selected from one or more of calcium stearate, magnesium stearate, zinc stearate.

Fluorine atoms are known to have ultra-low surface tension and so fluorine-containing compounds such as PTFE (fluorosurfactant) are commonly used to regulate and improve polypropylene surface properties. However, the fluorine-containing compounds are gradually recognized to bring harmful substances in long-term production or use, and are not friendly to the environment; the use of fluorochemicals has begun to be gradually limited and reduced. Thus, in some embodiments of the present invention, the polypropylene plastic need not contain any fluorine-containing compound.

The method for preparing the polypropylene plastic comprises the following steps: (1) Providing a mixture comprising a polypropylene resin, an antimicrobial agent, diatomaceous earth, and a stearate; (2) The mixture is melt extruded to form a polypropylene plastic. On the one hand, PDMS is selected to carry out surface modification on diatomite, and the modified diatomite is filled in polypropylene plastic, so that the polypropylene composite material is ensured to have lower surface tension under the condition of existence of an antibacterial agent, and meanwhile, the antibacterial effect of the polypropylene plastic is not influenced. On the other hand, inorganic antibacterial agents are safer and more durable than organic antibacterial agents. The inventors found that: the silver ion antibacterial agent has better antibacterial effect in the polypropylene plastic of the invention, and the copper ion and zinc ion antibacterial agent has better mildew-proof effect in the polypropylene plastic of the invention. Therefore, the polypropylene antibacterial plastic has lasting antibacterial and mildew-proof effects by selecting the specific type antibacterial mildew-proof agent.

In a specific embodiment, the preparation method of the polypropylene plastic mainly comprises the following steps: weighing raw materials according to the proportion, mixing polypropylene resin, a monoatomic antibacterial agent, PDMS modified diatomite and stearate by a high-speed mixer, wherein the rotating speed of the high-speed mixer is 400-800 revolutions per minute (rpm), the mixing time is 3-5 minutes, and after mixing, the mixed materials are subjected to melt extrusion by a double-screw extruder, cooling and granulating to obtain a polypropylene composite material; the extrusion temperature is 80-220 ℃, and the rotation speed of the twin-screw extruder is 300-500 revolutions per minute (rpm).

In an embodiment of the invention, the method further comprises: adding a silane coupling agent into the diatomite, and mixing; the diatomaceous earth was wetted with a silane coupling agent, then PDMS was added, and after mixing, the PDMS surface-modified diatomaceous earth was formed. In the invention, the silane coupling agent is an amino-functional silane coupling agent. In particular embodiments of the present invention, gamma-aminopropyl triethoxysilane (KH-550) may be employed. In a specific embodiment, the diatomite and the silane coupling agent are added into a grinder for mixing, so that the alcohol hydroxyl groups in the silane coupling agent are fully associated with the adsorption hydrogen bonds on the surface of the diatomite, and the silane coupling agent is fully grafted onto the diatomite, so that the surface of the diatomite is provided with an amino structure. And adding PDMS with hydroxyl at the tail end, and continuing mixing to fully coat the PDMS on the surface of the diatomite, so that the amino group on the diatomite and the hydroxyl on the PDMS form chemical bonding. Then, the mixture was dried in an oven to obtain a PDMS-covered diatomaceous earth. Wherein, the diatomite comprises PDMS and the silane coupling agent comprises (5-10) and (1) according to the weight portion ratio.

As an example, the PDMS surface-modified diatomaceous earth of the present invention was prepared using the following method: the diatomaceous earth was added to a small mill, and the silane coupling agent KH-550 was added in a weight ratio of diatomaceous earth to silane coupling agent=50:1, and mixed, wherein the rotation number of the small mill was 600 rotations per minute (rpm), and the mixing was about 3 to 5 minutes. And then adding PDMS in the weight ratio of PDMS to diatomite=1:10, continuing mixing for 3-5 minutes, taking out the mixed mixture, and putting the mixture into a drying oven for drying, wherein the drying temperature of the drying oven is 105 ℃ and the drying time is 30-60 minutes, so as to obtain the diatomite with low surface energy, the surface of which is coated and modified by PDMS. In the present invention, the PDMS surface modified diatomaceous earth has a surface tension of less than or equal to 20.9mN/m.

In an embodiment of the invention, the method does not include any step of actively adding the fluorochemical.

Examples

The invention will be further illustrated with reference to specific examples.

All the raw materials used in the embodiment of the invention are commercially available, and are as follows:

(1) Polypropylene resin: EM248U, liande Barceiser, under conditions of 230 ℃ and 2.16kg, the melt index MFR was 24g/10 min;

(2) Monoatomic antibacterial agents: a particle size of 4000 mesh, co-kowa technologies limited, wherein the carrier is diatomaceous earth and the transition metal comprises copper, zinc and/or silver monoatoms;

(3) PDMS: the viscosity of the Chinese medicine group chemical reagent is 5000cp;

(4) Silane coupling agent KH550: gamma-aminopropyl triethoxysilane, frifumorning photochemical company;

(5) Diatomaceous earth: particle size 600 mesh, national medicine group chemical agent Co., ltd;

(6) Stearate: zinc stearate, terstage one, a company of oil chemical industry, wangjiang, hangzhou.

Various performance testing methods used in embodiments of the present invention

(1) Antibacterial properties: QB/T2591-2003 antibacterial plastic-antibacterial performance test method and antibacterial effect.

(2) Mildew-proof performance: JIS Z2911:2018 annex A plastic product mildew-proof experiment method; wherein the test strain is Aspergillus niger, penicillium funiculosum, trichoderma viride, mucor sphaeroides and Paecilomyces variotii; rating criteria:

Level 0: visual inspection and no fungal growth under a microscope, the area of inhibition was visible around the test sample, and its width was recorded in mm;

Stage 1: mould growth was not seen visually, but was seen under a microscope;

2 stages: hypha growth can be obviously seen by visual inspection, and the mould growth area of the sample cannot exceed 25% of the total area of the sample; and

3 Stages: hypha growth can be obviously seen by visual inspection, and the mould growth area of the sample accounts for 25% -50% of the total area of the sample.

(3) Surface tension: GB/T14216-2008 determination of the wetting tension of Plastic films and sheets.

The components of the polypropylene plastics of examples 1-3 and comparative examples 1-4 are shown in Table 1 in parts by weight.

Table 1:

the preparation methods of examples 1-3 and comparative examples 1-4 include the following steps:

(1) Preparation of PDMS surface modified diatomaceous earth

Adding diatomite into a small grinder according to the weight ratio of 50: adding KH550 silane coupling agent into the mixture, mixing the mixture at 600rpm for 3 to 5 minutes, adding PDMS into the mixture according to the weight ratio of PDMS to diatomite of 10:1, continuously mixing the mixture for 3 to 5 minutes, taking out the mixed mixture, drying the mixture in an oven at 105 ℃ for 30 to 60 minutes, and obtaining the diatomite with low surface energy, the surface of which is coated by PDMS.

(2) The polypropylene resin, the monoatomic antibacterial agent, the PDMS surface-modified diatomaceous earth prepared in the above (1) and zinc stearate were weighed according to parts by weight described in table 1, and mixed in a high-speed mixer at 600rpm for about 3 minutes to obtain a mixed raw material.

(3) The mixed raw materials are fed into a main feeding bin of a tightly meshed and co-rotating double-screw extruder, the screw diameter of the extruder is 35mm, the length-diameter ratio L/D is 40, and the temperature of each partition from a feeding hole to a head outlet of a main machine barrel is set as follows: the polypropylene plastic is obtained through the processes of melting extrusion, cooling, granulating, drying and the like at 120 ℃, 180 ℃, 190 ℃, 210 ℃,220 ℃ and 200 ℃ with the rotation speed of a host machine of 400 rpm.

The polypropylene plastics prepared according to table 1 were prepared according to the above test methods and requirements to perform antibacterial property, mold resistance and surface tension tests, and the test results are shown in table 2.

Table 2: performance test results of Polypropylene plastics

As described above, the surface tension of the polypropylene plastic can be effectively reduced and the adhesion of dust, aerosol and microorganisms can be prevented by adding PDMS surface modified diatomaceous earth according to examples 1 to 3 of the present invention. As can be seen from comparing example 3 with comparative examples 1 and 5, PDMS surface modified diatomaceous earth and an antimicrobial (e.g., a monoatomic antimicrobial) can produce a synergy in polypropylene plastic, providing better mold resistance, achieving both visual inspection and no fungal growth under a microscope. The diatomite (unmodified) cannot generate a synergistic effect with the antibacterial agent, and cannot provide a better mildew-proof effect. In comparative examples 1 and 5, although mold growth was not seen visually, mold growth was seen under a microscope.

It is to be understood that these examples are illustrative of the present application and are not intended to limit the scope of the present application. Further, it is understood that various changes and modifications of the present application may be made by those skilled in the art after reading the contents of the present application, and such equivalents are also within the scope of the present application as defined in the appended claims.

Claims

1. A polypropylene plastic comprising, in parts by weight of the polypropylene plastic:

(1) 85-94 parts of polypropylene resin;

(2) 1 to 5 parts of an antibacterial agent; and

(3) 5-10 Parts of PDMS surface modified diatomite;

wherein the antimicrobial agent is a monoatomic antimicrobial agent comprising a carrier and a transition metal, wherein the carrier is selected from one or more of titanium dioxide, diatomaceous earth, calcium carbonate, kaolin, alumina and zeolite molecular sieves, and the transition metal is selected from one or more of copper, zinc and silver;

the polypropylene plastic does not contain any fluorine-containing compound; and is also provided with

The PDMS surface modified diatomite is mixed by adding a silane coupling agent into diatomite; adding PDMS, and mixing to form; wherein the silane coupling agent is a silane coupling agent with amino functional groups.

2. The polypropylene plastic according to claim 1, wherein the polypropylene plastic further comprises, based on the weight of the polypropylene plastic: (4) 0.1 to 0.5 parts of stearate.

3. The polypropylene plastic according to claim 1, wherein the diatomaceous earth has a weight average particle diameter of 5 to 30 microns.

4. A method of making the polypropylene plastic of claim 1, the method comprising:

(1) Providing a mixture comprising a polypropylene resin, an antimicrobial agent, and PDMS surface-modified diatomaceous earth;

(2) Melt extruding the mixture to form a polypropylene plastic;

Wherein the antimicrobial agent is a monoatomic antimicrobial agent; the monoatomic antibacterial agent comprises a carrier and transition metal, wherein the carrier is selected from one or more of titanium dioxide, diatomite, calcium carbonate, kaolin, aluminum oxide and zeolite molecular sieve, and the transition metal is selected from one or more of copper, zinc and silver;

wherein the method further comprises: adding a silane coupling agent into diatomite, and mixing; adding PDMS, and mixing to form the PDMS surface modified diatomite; wherein the silane coupling agent is a silane coupling agent with amino functional groups; and is also provided with

The method does not include any step of adding a fluorochemical.

5. The method of claim 4, wherein the diatomaceous earth has a weight average particle size of from 5 to 30 microns.