Flame-retardant and antibacterial nano functional composite flame-retardant master batch and preparation method thereof

Abstract

The present application relates to a kind of nanometer functional composite flame-retardant master batch with flame-retardant antibacterial function and its preparation method, the flame-retardant master batch includes the following weight parts of raw material components: elastomer matrix 20-40 parts, dopamine modified DOPO derivative 20-30 parts, phosphite 20-30 parts, multi-stage transition metal nanomaterial 5-20 parts, radical scavenger 5-10 parts, plastic additive 1-3 parts.Compared with prior art, the present application can effectively solve the material combustion defects, antibacterial defects and precipitation defects, and simplify production process, reduce the negative impact on material mechanical properties, etc.

Description

Technical Field

[0001] This invention belongs to the field of flame retardant synthesis technology, and relates to a composite flame retardant masterbatch with both flame retardant and antibacterial nano-functional properties and its preparation method. Background Technology

[0002] Polyolefins possess excellent mechanical properties, corrosion resistance, and ease of processing. They also have a wide processing temperature range and mature modification methods, leading to their widespread application in the automotive, electrical, and rail transportation industries. However, the long, straight carbon chain structure of PP molecules makes PP materials burn violently after ignition. PP's hydrocarbon structure gives it an ignition temperature of 340℃, an auto-ignition temperature of 350℃, and a limiting oxygen index (LOI) of only 18%, classifying it as an extremely flammable material with rapid flame spread, high heat generation, and significant dripping and efflorescence during combustion. Therefore, research on flame-retardant modification of PP materials is essential.

[0003] Meanwhile, with the development of modern technology, various fields are placing increasing demands on the comprehensive performance of materials, such as antibacterial properties, flame retardancy, comfort, and wear resistance. Traditionally, the melting and processing of powdered additives and resins for polypropylene typically employs a twin-screw extrusion process. During this process, all matrix resins and modifying additives must undergo two melting and thermal processes: twin-screw extrusion and injection molding. This leads to varying degrees of degradation in the polymer molecular chains and related modifying additives, resulting in a shortened long-term service life for plastic products. This technical approach also increases the processing cycle and energy consumption of modified plastics, contradicting the fundamental principles of current green and sustainable industrial development. Furthermore, the processes and equipment requirements vary significantly depending on the structure and performance characteristics of different additives and raw materials. This is one of the typical drawbacks of powdered additives, resulting in generally low tolerance for error and limited universality.

[0004] Functional masterbatches are one of the main ways to solve the inherent defects of powder additives. They have three advantages: 1) They can significantly reduce dust hazards during processing and enable the creation of cleanrooms; 2) They can reduce shear heat generation during processing, thereby reducing the negative impact on material properties; 3) They can concentrate multiple functions in a single masterbatch, simplifying material preparation processes and procedures.

[0005] The current development trend of functional masterbatches is gradually moving towards higher effective component content, multi-functionality, and high performance. In public sectors such as automotive, medical, and rail transportation, materials are required to exhibit broader comprehensive properties beyond basic performance, particularly flame retardancy, antibacterial properties, and weather resistance. Currently, masterbatches that have achieved large-scale industrial production in plastics, including flame-retardant masterbatches, color masterbatches, and antibacterial masterbatches, are all single-function masterbatches with relatively low effective component content. Summary of the Invention

[0006] The purpose of this invention is to provide a composite flame-retardant masterbatch with both flame-retardant and antibacterial nano-functional properties and its preparation method, which effectively solves the problems of material combustion defects, antibacterial defects and precipitation defects, simplifies the production process, and reduces the negative impact on the mechanical properties of the material.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] One of the technical solutions of the present invention provides a composite flame-retardant masterbatch with both flame-retardant and antibacterial nano-functional properties, comprising the following raw material components in parts by weight: 20-40 parts of elastomer matrix, 20-30 parts of dopamine-modified DOPO derivative, 20-30 parts of phosphite, 5-20 parts of multi-level transition metal nanomaterials, 1-5 parts of free radical scavenger, and 1-3 parts of plastic additives.

[0009] Furthermore, the elastomer matrix is ​​one or a combination of several of the following: propylene-based elastomers and ethylene butyl acrylate.

[0010] Furthermore, the elastomer matrix is ​​a high-flow resin with a melt index > 50 g / 10 min.

[0011] Furthermore, the dopamine-modified DOPO derivative is prepared by the following method:

[0012] (A) Add DOPO and dopamine to a reaction vessel, add chloroform under a nitrogen atmosphere, stir until DOPO is completely dissolved, then add tris(hydroxymethyl)aminomethane, heat and continue the reaction. Cool the resulting reaction solution to room temperature and stir until a white precipitate appears. Filter and dry to obtain a white powder, denoted as DA@DOPO.

[0013] (B) Place DA@DOPO in a vacuum muffle furnace, heat it, and then calcine it to obtain the dopamine-modified DOPO derivative.

[0014] Furthermore, in step (A), the ratio of the amount of DOPO, dopamine, chloroform, and tris(hydroxymethyl)aminomethane added is (4-6)g:1g and (80-120)ml:(0.8-1.2)g; specifically, the ratio of the amount of DOPO, dopamine, chloroform, and tris(hydroxymethyl)aminomethane added is 5g:1g:100ml:1g.

[0015] Furthermore, in step (A), after adding chloroform, the mixture is stirred at 70-100°C, and the reaction continues at 80-120°C for 6 hours.

[0016] Furthermore, in step (B), the heating treatment temperature is 160-200℃, preferably 180℃, and the time is 2-4h, preferably 3h.

[0017] Furthermore, the phosphite is one of aluminum phosphite and zinc phosphite.

[0018] Furthermore, the aforementioned multi-level transition metal nanomaterials are prepared by the following method:

[0019] (a) Weigh out bismuth nitrate and dissolve it in deionized water, then add ammonium vanadate, react, adjust the pH to neutral, continue the reaction, filter and dry to obtain nano bismuth vanadate;

[0020] (b) The obtained nano-bismuth vanadate was dissolved in deionized water, ferric nitrate pentahydrate was added, the temperature was continuously raised to 50-80℃, stirred, and the pH was adjusted to 7-8. The reaction was carried out, and the resulting product was filtered, washed, and dried to obtain Fe@BiVO4 nanomaterials, which are multi-level transition metal nanomaterials.

[0021] Furthermore, the ratio of the amount of bismuth nitrate, ammonium vanadate, and ferric nitrate pentahydrate added is (80-100):(50-80):(80-100).

[0022] Furthermore, in step (a), after adding ammonium vanadate, the reaction time is 1-2 hours, and the reaction continues for 24-48 hours.

[0023] Furthermore, in step (b), the reaction time is 24-48 hours.

[0024] Furthermore, the free radical scavenger is one or a mixture of several of N,N-dibenzylhydroxylamine (DBHA), carbon nanotubes, and multilayer graphene. More specifically, the N,N-dibenzylhydroxylamine (DBHA) is N,N-dibenzylhydroxylamine (DBHA) with a purity greater than 99%; the carbon nanotubes are one of single-walled carbon nanotubes and multi-walled carbon nanotubes; the multilayer graphene does not contain metal ions, has a thickness of less than 2.0 nm, has 2-4 layers, and a layer diameter of 1.0-2.0 micrometers.

[0025] Furthermore, the plastic additives include antioxidants, light stabilizers, and / or flow modifiers.

[0026] More specifically, the antioxidant is any one or a mixture of several of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 1,3,5-tris(3,5-tert-butyl-4-hydroxybenzyl)trimethylbenzene, and 4,4'-di-tert-octyldiphenylamine.

[0027] Specifically, the light stabilizer is one of the hindered amine structures.

[0028] Specifically, the flow modifier is one of silicone powder and stearate.

[0029] The second technical solution of the present invention provides a method for preparing a composite flame-retardant masterbatch with both flame-retardant and antibacterial nano-functional properties, comprising the following steps:

[0030] (1) Weigh 20-40 parts of elastomer matrix, 20-30 parts of dopamine-modified DOPO derivative, 20-30 parts of phosphite, 5-20 parts of multi-level transition metal nanomaterials, 5-10 parts of free radical scavenger, and 1-3 parts of plastic additives and mix them to obtain a mixture.

[0031] (2) The mixture obtained in step (1) is fed into a screw extruder and melt-extruded into granules to obtain composite flame retardant masterbatch.

[0032] Furthermore, in step (2), the extrusion temperature of the twin-screw extruder is between 180-220℃, the main engine speed is 100-200rpm, and the feeding frequency is 10-15Hz. Specifically, the twin-screw extruder includes a melting section, a conveying section, a mixing section, a homogenizing section, and a metering section arranged sequentially, with the temperatures of each section set sequentially to 190-200℃, 190-210℃, 190-210℃, 190-210℃, and 200-220℃. Simultaneously, the twin-screw extruder can be configured such that the internal structure does not contain 90-degree shear blocks, and the shearing section mainly consists of 60-degree shear blocks, 45-degree shear blocks, and toothed discs arranged alternately.

[0033] Furthermore, the mixing is carried out in a vertical double-helix conical mixer, which has two asymmetrical cantilevered helices with a revolution speed of 100-150 rpm and a rotation speed of 50-100 rpm. The internal blades are arranged in an alternating pattern, and the mixing time is 3-5 minutes.

[0034] Generally, the introduction of flame retardants and other additives disrupts the continuous phase of the material due to the "island" structure formed by rigid particles, resulting in unpredictable impacts on the material's physical properties. Simultaneously, poor dispersion and surface energy make additives prone to agglomeration within the material. Flame retardancy and antibacterial properties are among the main requirements for polymer materials. However, composite materials with complex functions require the introduction of multiple additives, which may lead to performance degradation during processing. Furthermore, the repeated thermal histories during extrusion and injection molding can cause material degradation during processing. The introduction of multifunctional flame-retardant and nano-antibacterial systems endows the prepared masterbatch with multifunctional characteristics. Furthermore, based on the performance characteristics of various powder additives in the formulation system, a formulation system design was implemented to promote lubrication and efficient dispersion.

[0035] Masterbatch can be directly mixed with resin in a certain ratio according to performance requirements and then injection molded, including but not limited to: copolymer polypropylene, homopolymer polypropylene, high-density polyethylene, low-density polyethylene, thermoplastic elastomers, etc. Because the injection molding machine uses a single-screw melt propulsion mode, the shearing effect on the matrix and masterbatch is very weak, and it will basically not damage the modification effect of either.

[0036] In summary, this invention is based on transition metal catalysis and antibacterial mechanisms, the design and synthesis of high-valence phosphorus-containing flame retardants, and introduces a free radical capture system to construct a multifunctional masterbatch with highly efficient flame retardant and antibacterial effects. Directly using this flame-retardant masterbatch for injection molding avoids the problems of mutual loss of modified additive efficacy and processing temperature mismatch that occur during plastic reinforcement and functional modification. It also maximizes the modification efficacy of different material modified additives and auxiliaries, and avoids the need for re-extrusion granulation of traditional functional masterbatches and matrix resins. This effectively improves the plastic modification effect, reduces production cycle time, and saves energy consumption.

[0037] Compared with the prior art, the present invention has the following advantages:

[0038] 1) Due to the lack of nitrogen in DOPO, a biomass dopamine structure was introduced. While supplementing the deficiency of acid source in flame retardants, the introduced biomass polydopamine structure also has significant antibacterial and bio-friendly properties, realizing a multifunctional combination of flame retardancy, antibacterial and bio-friendly properties, effectively reducing the final biomass hazards of the masterbatch system.

[0039] 2) After the dopamine structure is directionally grown on the surface of micron-sized DOPO, a rough micro-nano structure is formed. When introduced into the composite material, it increases the compatibility between the matrix resins and reduces the precipitation of the flame retardant system and its impact on mechanical properties.

[0040] 3) Employing in-situ polymerization and chemical deposition techniques, multi-level nanomaterials with both stability and functionality were constructed. The photocatalytic effect of bismuth electron transitions and the catalytic carbonization effect of high-valence iron ions were combined within the nanomaterials, achieving multifunctional construction including flame retardancy and smoke suppression. Simultaneously, the free radical capture system introduced into the masterbatch system can capture unstable free radicals in the gas phase during material combustion, interrupting and inhibiting chain reactions during combustion.

[0041] 4) Compared with traditional single-function masterbatches, the multifunctional masterbatch prepared by this invention effectively improves the flame retardancy and antibacterial properties of plastics, while simplifying the plastic modification and processing steps, reducing the processing cycle, reducing energy consumption, and improving production efficiency, truly realizing the concept of green chemical development.

[0042] The methods and techniques of this invention can be widely applied to the integrated processing of injection molding, high-performance modification, and functionalization of various polypropylene plastic products. Detailed Implementation

[0043] The present invention will now be described in detail with reference to specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0044] 1. Components used

[0045] Commercially available elastomer: EBA, purchased from Arkema Ltd., France, grade 17BA 07.

[0046] PDA@DOPO: Self-made, the specific process is as follows:

[0047] 1) Add 5g of DOPO and 1g of dopamine to a 500mL three-necked round-bottom flask at a specific molar ratio. Reflux under nitrogen protection, and then add 100mL of chloroform. Stir at 85℃ for a certain time until DOPO is completely dissolved. Then add 1g of tris(hydroxymethyl)aminomethane, and raise the temperature to 100℃ to continue the reaction for 6 hours. After the reaction is complete, cool the reaction solution to room temperature and stir at room temperature until a white precipitate appears. Filter under reduced pressure, dry under vacuum, and seal for storage to obtain a white powder, DA@DOPO.

[0048] 2) Place DA@DOPO in a vacuum muffle furnace, heat to 180°C, and maintain for 3 hours to allow DA to self-polymerize into polydopamine (PDA), and the product is PDA@DOPO.

[0049] Fe@BiVO4: Homemade, the specific process is as follows:

[0050] 1) Weigh 9g of bismuth nitrate and dissolve it in 500mL of deionized water. Stir continuously at a speed of about 150rpm. Then weigh 6.5g of ammonium vanadate and add it to the above deionized water. After reacting for about 1.5h, adjust the pH to neutral with ammonia water and continue the reaction for about 36h. Filter and dry to obtain nano bismuth vanadate.

[0051] 2) Dissolve the obtained nano-bismuth vanadate in deionized water, add about 9g of ferric nitrate pentahydrate, continuously heat to 50℃, stir at 100-200rpm, slowly add sodium hydroxide until pH is 8, react for 36h, filter and wash, and dry at 100℃ to obtain Fe@BiVO4 nanomaterials.

[0052] Aluminum phosphite: Shenzhen Ruishixing Technology Co., Ltd., grade PA2103.

[0053] Graphene microsheets: Shanghai Xili Carbon Co., Ltd., brand name Carbon56;

[0054] Antioxidants: BASF Chemicals, grades 1010 and 168.

[0055] Light stabilizer: Shanghai Dingfen Chemical Technology Co., Ltd., grade 944.

[0056] Flow modifier: Henan Shengkun Chemical Products Co., Ltd., brand name: silicone powder.

[0057]

[0058]

[0059]

[0060] Table 2 shows the performance data of the composite materials formed under different combinations. After being prepared into masterbatches using DOPO derivatives, Fe@BiVO4, and aluminum phosphite, the composites exhibited good antibacterial properties, flame retardancy, and excellent mechanical properties when directly injection molded with polypropylene. The flame retardancy, mechanical properties, and antibacterial properties of the obtained composites were further improved after the introduction of a free radical scavenging system. In Example 6, compared to Example 3, the introduction of graphene microsheets further improved the flame retardant properties. Compared to Example 7, the mechanical strength, especially the impact strength, of the prepared composite material after replacing DOPO with PDA@DOPO was significantly improved, indicating that the introduction of PDA@DOPO increased the compatibility of the system, while its antibacterial effect was significantly enhanced. Compared to Example 8, the introduction of Fe@BiVO4 after replacing BiVO4 significantly increased the catalytic char formation effect and antibacterial effect of the system, further improving the comprehensive performance of the composite material, especially the limiting oxygen index and antibacterial rate. Meanwhile, graphene microsheets, PDA@DOPO, and Fe@BiVO4 exhibit synergistic effects due to their suitable P / N ratio, excellent compatibility, and metal ion catalytic char formation and antibacterial properties. This not only significantly improves the flame retardant and mechanical properties of the material but also provides significant antibacterial effects. Furthermore, in a comparative example, the composite materials obtained by direct injection molding from the masterbatch show significantly better performance than plastic products produced by extrusion injection molding. Utilizing the functional masterbatch of this invention not only greatly simplifies the polypropylene resin modification process, improves processing efficiency, and reduces energy consumption but also significantly enhances the modification effect, realizing the sustainable development concept of green processing in plastics manufacturing. This invention greatly increases the safety and versatility of polypropylene materials in certain fields, overcoming the difficulty of effectively balancing physical properties with other properties, and enabling applications in harsher environments.

[0061] Example 9:

[0062] Compared with Example 1, most of them are the same, except that in this example, the proportions of various raw materials are adjusted as follows: 20 parts of elastomer matrix, 30 parts of dopamine-modified DOPO derivative, 20 parts of phosphite, 5 parts of multi-level transition metal nanomaterials, 5 parts of free radical scavenger, and 3 parts of plastic additives. Among them, the raw material components containing multiple components are adjusted proportionally.

[0063] Example 10:

[0064] Compared with Example 1, most of them are the same, except that in this example, the proportions of various raw materials are adjusted as follows: 40 parts of elastomer matrix, 20 parts of dopamine-modified DOPO derivative, 25 parts of phosphite, 20 parts of multi-level transition metal nanomaterials, 10 parts of free radical scavenger, and 1 part of plastic additives. Among them, the raw material components containing multiple components are adjusted proportionally.

[0065] Example 11:

[0066] Most of the contents are the same as in Example 1, except that in this example, aluminum phosphite is replaced with an equal mass of zinc phosphite.

[0067] Examples 12-13:

[0068] The majority of the contents are the same as in Example 1, except that in this example, the graphene microsheets are replaced with equal masses of N,N-dibenzylhydroxylamine (DBHA) and carbon nanotubes.

[0069] Example 14:

[0070] Most of the contents are the same as in Example 1, except that in this example, the silicone powder is replaced with an equal mass of sodium stearate.

[0071] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A composite flame-retardant masterbatch with both flame-retardant and antibacterial nano-functional properties, characterized in that, The raw material components include the following parts by weight: 20-40 parts of elastomer matrix, 20-30 parts of dopamine-modified DOPO derivative, 20-30 parts of phosphite, 5-20 parts of multi-level transition metal nanomaterials, 1-5 parts of free radical scavenger, and 1-3 parts of plastic additives. The elastomer matrix is ​​one or a combination of several of the following: propylene-based elastomers and ethylene-butyl acrylate copolymers; The dopamine-modified DOPO derivative was prepared by the following method: (A) Add DOPO and dopamine to a reaction vessel, add chloroform under a nitrogen atmosphere, stir until DOPO is completely dissolved, add tris(hydroxymethyl)aminomethane, heat and continue the reaction, cool the resulting reaction solution to room temperature and stir until a white precipitate appears, filter, wash and dry to obtain a white powder, denoted as DA@DOPO; (B) Place DA@DOPO in a vacuum muffle furnace and heat it to obtain dopamine-modified DOPO derivatives; The aforementioned multi-level transition metal nanomaterials were prepared by the following method: (a) Weigh out bismuth nitrate and dissolve it in deionized water, then add ammonium vanadate, react, adjust the pH to neutral, continue the reaction, filter and dry to obtain nano bismuth vanadate; (b) The obtained nano-bismuth vanadate is dissolved in deionized water, ferric nitrate pentahydrate is added, the temperature is continuously raised to 50-80℃, stirred, and the pH is adjusted to 7-8. The reaction is carried out, and the product is filtered, washed and dried to obtain Fe@BiVO4 nanomaterials, which are multi-level transition metal nanomaterials. In step (A), the ratio of the amount of DOPO, dopamine, chloroform, and tris(hydroxymethyl)aminomethane added is (4-6) g: 1 g: (80-120) ml: (0.8-1.2) g; In step (A), after adding chloroform, the mixture is stirred at 70-100℃, and the reaction continues at 80-120℃ for 6 hours. In step (B), the heating treatment temperature is 160-200℃ and the time is 2-4 hours; The ratio of the amount of bismuth nitrate, ammonium vanadate, and ferric nitrate pentahydrate added is (80-100):(50-80):(80-100).

2. The composite flame-retardant masterbatch with both flame-retardant and antibacterial nano-functional properties according to claim 1, characterized in that, The melt index of the elastomer matrix is ​​>50 g / 10 min.

3. The composite flame-retardant masterbatch with both flame-retardant and antibacterial nano-functional properties according to claim 1, characterized in that, The phosphite mentioned is one of aluminum phosphite and zinc phosphite.

4. The composite flame-retardant masterbatch with both flame-retardant and antibacterial nano-functional properties according to claim 1, characterized in that, In step (a), after adding ammonium vanadate, the reaction time is 1-2 hours, and the reaction time continues for 24-48 hours; In step (b), the reaction time is 24-48 hours.

5. The composite flame-retardant masterbatch with both flame-retardant and antibacterial nano-functional properties according to claim 1, characterized in that, The free radical scavenger is one or a mixture of N,N-dibenzylhydroxylamine, carbon nanotubes, and multilayer graphene; The plastic additives include antioxidants, light stabilizers, and / or flow modifiers.

6. A method for preparing a composite flame-retardant masterbatch with both flame-retardant and antibacterial nanofunctional properties as described in any one of claims 1-5, characterized in that, Includes the following steps: (1) Weigh 20-40 parts of elastomer matrix, 20-30 parts of dopamine-modified DOPO derivative, 20-30 parts of phosphite, 5-20 parts of multi-level transition metal nanomaterials, 1-5 parts of free radical scavenger, and 1-3 parts of plastic additives and mix them to obtain a mixture; (2) The mixture obtained in step (1) is fed into a screw extruder and melt-extruded into granules to obtain composite flame retardant masterbatch; In step (2), the extrusion temperature of the twin-screw extruder is between 180-220℃, the main machine speed is 100-200rpm, and the feeding frequency is 10-15Hz.

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