Halogen-free environment-friendly antibacterial conjugated flame-retardant PP material and preparation method thereof

Abstract

The invention provides a halogen-free environment-friendly antibacterial conjugated flame-retardant PP material and a preparation method thereof. The halogen-free environment-friendly antibacterial conjugated flame-retardant PP material is prepared from the following raw materials in parts by weight: 90-100 parts of a polypropylene base material; 15 to 20 parts of a halogen-free flame retardant; 1 to 2 parts of functionalized nanoparticles; 3-6 parts of a toughening agent; and 1-3 parts of a coupling agent. The halogen-free flame retardant disclosed by the invention can release phosphorus-containing free radicals in a combustion process, capture active free radicals in flame, inhibit flame propagation and improve the flame retardant property of the material. By adding the POE, polyurethane or rubber flexibilizer, the toughness and impact resistance of the material are remarkably improved, and the material is ensured not to be easily broken under the action of external force. Due to the addition of functional nanoparticles such as nano zinc oxide, the material is endowed with good antibacterial performance, and the material is widely applied to the fields of medical treatment and food packaging. The halogen-free flame retardant is adopted, so that the pollution of halogen compounds to the environment is reduced, and the green and environment-friendly requirements are met.

Description

Technical Field

[0001] The present invention relates to the technical field of environmental protection materials, and particularly to a halogen-free environmental protection antibacterial conjugated flame-retardant PP material and a preparation method thereof. Background Art

[0002] Polypropylene (PP) is a thermoplastic widely used in fields such as food packaging, automotive parts, petrochemical industry, and medical and health. It has good mechanical strength, chemical stability, and processing performance. However, polypropylene materials have the problem of being flammable during use, especially restricted in applications that require flame-retardant performance.

[0003] Traditional flame-retardant PP materials mostly use halogen-containing flame retardants, but these halogen-based flame retardants are highly harmful to the environment and human body. Therefore, the application of halogen-free flame retardants has become crucial. Existing halogen-free flame retardants usually require a relatively high addition amount to achieve an ideal flame-retardant effect, which will cause a significant decline in the mechanical properties of the material. Therefore, how to improve the mechanical properties and environmental protection performance of the material while maintaining excellent flame-retardant performance has become an important topic in the research of polypropylene composites. Summary of the Invention

[0004] The purpose of the present invention is to provide a halogen-free environmental protection antibacterial conjugated flame-retardant PP material and a preparation method thereof, which can significantly improve the mechanical properties, antibacterial properties, and thermal stability of the material while ensuring excellent flame-retardant performance.

[0005] According to one object of the present invention, a halogen-free environmental protection antibacterial conjugated flame-retardant PP material is provided, which is composed of the following raw materials in parts by weight:

[0006] 90 - 100 parts of polypropylene substrate;

[0007] 15 - 20 parts of halogen-free flame retardant;

[0008] 1 - 2 parts of functionalized nanoparticles;

[0009] 3 - 6 parts of toughening agent;

[0010] 1 - 3 parts of coupling agent.

[0011] Further, the halogen-free flame retardant is a 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivative with a conjugated structure.

[0012] Further, the toughening agent is one or a combination of several of POE, polyurethane, or rubber.

[0013] Further, the functionalized nanoparticles are one or a combination of two of nano-zinc oxide and nano-calcium carbonate.

[0014] Further, the coupling agent is one or a combination of several of isopropyl tris(dioctylpyrophosphato) titanate (KR-38S) and aluminate ester.

[0015] According to another object of the present invention, the present invention provides a method for preparing the above-mentioned halogen-free environmentally friendly antibacterial conjugated flame-retardant PP material, comprising the following steps:

[0016] S1. Raw material preparation:

[0017] Weigh the raw materials accurately according to the formula ratio, and accurately weigh the polypropylene substrate (90 - 100 parts), halogen-free flame retardant DiDOPO (15 - 20 parts), functionalized nanoparticles (1 - 2 parts), toughening agent (3 - 6 parts) and coupling agent (1 - 3 parts).

[0018] S2. Mixing:

[0019] Pour all the solid raw materials into a high-speed mixer in sequence and carry out stirring and mixing to ensure uniform mixing of each component.

[0020] S3. Melting and extrusion:

[0021] Extrude the dry-mixed mixture through a twin-screw extruder.

[0022] S4. Drying treatment:

[0023] The extruded composite material is dried in a vacuum oven at 80 °C for 12 hours to remove any residual moisture.

[0024] Further, it also includes S5, finished product particle size control and testing:

[0025] Control the particle size of the final material within the range of 2 - 5 mm, and test the flame retardancy, mechanical properties and antibacterial properties of the sample to ensure meeting the design requirements.

[0026] Further, in S1, for the polypropylene raw material with strong hygroscopicity, it is dried using a vacuum drying oven.

[0027] Further, in S2, the stirring speed is set at 500 rpm and the mixing time is 10 - 20 minutes.

[0028] Further, in S3, the temperature of the twin-screw extruder is set as follows: feeding section 190 °C, conveying section 200 °C, compression section 205 °C, homogenization section 205 °C, transition section 210 °C, head section 205 °C; the screw speed is set at 320 r / min.

[0029] Beneficial effects

[0030] The halogen-free flame retardant in the technical solution of the present invention can release phosphorus-containing free radicals during combustion, capture active free radicals in the flame, inhibit flame propagation, and improve the flame retardant performance of the material. By adding toughening agents such as POE, polyurethane or rubber, the toughness and impact resistance of the material are significantly improved, ensuring that the material is not easily broken under external forces. The addition of functionalized nanoparticles such as nano-zinc oxide endows the material with good antibacterial properties and is widely used in the fields of medical treatment and food packaging. The use of halogen-free flame retardants reduces environmental pollution caused by halogen compounds and meets the requirements of green environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a flowchart for preparing the PP material according to an embodiment of the present invention;

[0032] Figure 2 It is a vertical combustion test diagram according to an embodiment of the present invention;

[0033] Figure 3 It is a comparison diagram of the test results of the antibacterial properties according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative work shall fall within the scope of protection of the present invention.

[0035] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the present invention.

[0036] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present invention, "a plurality of" means two or more unless otherwise specifically defined. In addition, the terms "installed", "connected", and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] Example 1

[0038] As Figures 1 to 3 shown,

[0039] A halogen-free environmentally friendly antibacterial conjugated flame-retardant PP material is composed of the following raw materials in parts by weight:

[0040] 90 - 100 parts of polypropylene substrate, 15 - 20 parts of halogen-free flame retardant, 1 - 2 parts of functionalized nanoparticles, 3 - 6 parts of toughening agent, and 1 - 3 parts of coupling agent.

[0041] In the present invention, by adding POE, polyurethane or rubber, the toughness and impact resistance of the material are significantly improved, ensuring that it is not easily broken when subjected to external forces, guaranteeing the product quality. And by adding functionalized nanoparticles zinc oxide, while maintaining excellent properties, the heat stability, flame retardancy, mechanical properties and antibacterial properties of the composite material are improved. Through this comprehensive optimization design, not only the physical and mechanical properties of the material are enhanced, but also its applicability in different application fields is expanded, and the product quality is improved.

[0042] Among them, the functionalized nanoparticles are one or a combination of two of nano zinc oxide and nano calcium carbonate, which are responsible for improving the heat stability, flame retardancy and mechanical properties of the composite material and endowing antibacterial properties. By improving the antibacterial properties of the material, it has excellent functions in fields where antibacterial properties need to be guaranteed, such as refrigerator storage boxes.

[0043] The halogen-free flame retardant is a 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivative (DiDOPO) with a conjugated structure

[0044] The toughening agent is one or a combination of several of POE, polyurethane or rubber.

[0045] The coupling agent is one or a combination of several of isopropyl tris(dioctylpyrophosphato)titanate (KR-38S) and aluminate ester.

[0046] As Figure 1 shown, the preparation process of the above-mentioned halogen-free environmentally friendly antibacterial conjugated flame-retardant PP material includes the following steps:

[0047] Step 1: Weigh the raw materials accurately according to the formula ratio, and at the same time, dry the raw materials with strong hygroscopicity such as polypropylene through a vacuum drying oven.

[0048] Monitor the moisture content of the raw materials to ensure that it is lower than 0.1%, and prevent the problems of bubble generation and poor material fluidity during subsequent processing due to too high moisture content.

[0049] Step 2: Pour all the solid raw materials into a high-speed mixer in sequence, set the stirring speed at 500 rpm, and the mixing time at 10 - 20 minutes.

[0050] During the mixing process, agglomerated fillers or additives may cause too high a concentration in some areas of the material, thereby reducing the performance of these areas and affecting the overall strength and stability of the product. Therefore, it is necessary to regularly check the uniformity of the mixture to avoid agglomeration.

[0051] Step 3: Melt-extrude and pelletize the dry-mixed mixture through a twin-screw extruder.

[0052] Set six heating zones to gradually heat during extrusion to ensure thorough and uniform melting of the material.

[0053] Step 4: Dry the extruded DiDOPO composite material in a vacuum oven at 80 °C for 12 hours to remove any residual moisture.

[0054] Among them, in the above-mentioned Step 3, the settings of the twin-screw extruder are: the feeding section is 190 °C, the conveying section is 200 °C, the compression section is 205 °C, the homogenization section is 205 °C, the transition section is 210 °C, and the head section is 205 °C. The screw speed is set at 320 r / min.

[0055] By setting six heating zones, the temperature of each heating zone can be gradually increased to better control the melting and mixing process of the material.

[0056] Among them, the particle size of the PP material is controlled within 2 - 5 mm, and after preparation, the flame retardancy, mechanical properties, and antibacterial properties of the sample are tested to ensure meeting the design requirements.

[0057] Among them, the flame retardancy performance was tested by vertical burning test to evaluate the flame retardant grade of the material. The mechanical properties were tested using an electronic universal testing machine (Instron) according to the GB / T 1040-92 standard. The antibacterial performance was evaluated by the plate coating method according to the standard of GB / T 31402-2015 to ensure compliance with industry standards.

[0058] Figure 2 Figure for the vertical burning test of PP materials. From left to right are pure PP material, PP material with 4wt% DiDOPO added, PP material with 8wt% DiDOPO added, PP material with 16wt% DiDOPO added (flame retardant grade reaches V-2), and PP material with 16wt% DiDOPO, 1wt% nano-zinc oxide and 3wt% POE added (flame retardant grade reaches V-0).

[0059] As Figure 3 shown, the antibacterial performance test results of this example. a. Staphylococcus aureus, b. Escherichia coli.

[0060] As shown in Table 1: Mechanical property table of the PP material prepared in this example.

[0061] Table 1

[0062]

[0063] By Figure 2 、 Figure 3 and shown in Table 1, the present invention adds a 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivative (DiDOPO) with a conjugated structure, making the prepared flame retardant PP have excellent flame retardancy performance, not easy to burn, with low smoke generation after combustion. At the same time, by adding polyurethane and functionalized nano-particle zinc oxide, the toughness and impact resistance of the material are improved, ensuring that it is not easy to break when subjected to external forces, guaranteeing product quality and endowing the material with good antibacterial performance.

[0064] The halogen-free flame retardant selected in the present invention is DiDOPO, which has low conductivity and poor charge transport ability. DiDOPO releases phosphorus-containing free radicals during the combustion process, and these free radicals can capture active free radicals in the flame (such as H·, O· or HO·), making the PP composite produce more CO and less CO2, thereby inhibiting flame propagation. And the addition of DiDOPO improves the melt stability of the PP composite, inhibits the melt dripping phenomenon of PP, reduces the possibility of heat carried away by the melt droplets during the combustion process, and thus improves the flame retardant effect.

[0065] By adding POE, polyurethane or rubber, the present invention significantly improves the toughness and impact resistance of the material, ensuring that it is not easily broken when subjected to external forces, guaranteeing the product quality. And by adding functionalized nanoparticles zinc oxide, while maintaining excellent properties, this kind of PP material improves the thermal stability, flame retardancy, mechanical properties and antibacterial properties of the composite material. Through this comprehensive optimization design, not only the physical and mechanical properties of the material are improved, but also its applicability in different application fields is expanded, and the product quality is improved.

[0066] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A halogen-free, environmentally friendly, antibacterial, conjugated flame-retardant PP material, characterized in that, It consists of the following raw materials in parts by weight: 90 - 100 parts of polypropylene substrate; 15 - 20 parts of halogen-free flame retardant; 1 - 2 parts of functionalized nanoparticles; 3 - 6 parts of toughening agent; 1 - 3 parts of coupling agent.

2. The halogen-free environmentally friendly antibacterial conjugated flame-retardant PP material according to claim 1, characterized in that, The halogen-free flame retardant is a 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivative with a conjugated structure.

3. The halogen-free, environmentally friendly, antibacterial and conjugated flame-retardant PP material according to claim 1, characterized in that, The toughening agent is one or a combination of several of POE, polyurethane, or rubber.

4. The halogen-free, environmentally friendly, antibacterial and conjugated flame-retardant PP material according to claim 1, wherein The functionalized nanoparticles are one or a combination of two of nano-zinc oxide and nano-calcium carbonate.

5. The halogen-free, environmentally friendly, antibacterial and conjugated flame-retardant PP material according to claim 1, characterized in that, The coupling agent is one or a combination of several of isopropyl tri(dioctylpyrophosphate acyloxy) titanate (KR-38S) and aluminate.

6. The preparation method of the halogen-free environmentally friendly antibacterial conjugated flame-retardant PP material according to claim 1, wherein It includes the following steps: S1. Raw material preparation: Accurately weigh the raw materials according to the formula ratio, and accurately weigh the polypropylene substrate (90 - 100 parts), halogen-free flame retardant DiDOPO (15 - 20 parts), functionalized nanoparticles (1 - 2 parts), toughening agent (3 - 6 parts), and coupling agent (1 - 3 parts); S2. Mixing: Pour all the solid raw materials into a high-speed mixer in sequence and carry out stirring and mixing to ensure uniform mixing of each component; S3. Melting and extrusion: Carry out melting and extrusion of the dry-mixed mixture through a twin-screw extruder; S4. Drying treatment: The extruded composite material is dried in a vacuum oven at 80 °C for 12 hours to remove any residual moisture.

7. The preparation method of the halogen-free environmentally friendly antibacterial conjugated flame-retardant PP material according to claim 6, characterized in that, It also includes S5, finished product particle size control and testing: Control the particle size of the final material within the range of 2 - 5 mm, and test the flame retardancy, mechanical properties, and antibacterial properties of the sample to ensure meeting the design requirements.

8. The preparation method of the halogen-free environmentally friendly antibacterial conjugated flame-retardant PP material according to claim 6, characterized in that, In S1, for the polypropylene raw material with strong hygroscopicity, it is dried using a vacuum drying oven.

9. The preparation method of the halogen-free environmentally friendly antibacterial conjugated flame-retardant PP material according to claim 6, characterized in that, In S2, set the stirring speed to 500 rpm and the mixing time to 10 - 20 minutes.

10. The preparation method of the halogen-free environmentally friendly antibacterial conjugated flame-retardant PP material according to claim 6, characterized in that, In S3, the temperature of the twin-screw extruder is set as follows: feeding section 190 °C, conveying section 200 °C, compression section 205 °C, homogenization section 205 °C, transition section 210 °C, head section 205 °C; the screw speed is set to 320 r / min.

Images