Efficient environment-friendly flame retardant applied to rubber and plastic foaming industry and preparation method of efficient environment-friendly flame retardant

Abstract

The invention relates to the technical field of flame-retardant materials, and discloses a high-efficiency environment-friendly flame retardant applied to the rubber and plastic foaming industry and a preparation method thereof.The flame retardant is prepared from, by weight, 25-40 parts of halogen compounds, 10-30 parts of transition metal oxides, 20-35 parts of alkaline earth metal hydroxides and 25-45 parts of borate compounds, the composite flame retardant is applied to a nitrile rubber foaming material. According to the invention, a plurality of powder materials with a synergistic flame-retardant effect are mixed through a high-speed stirrer, and different flame-retardant materials have a synergistic effect, so that the effect of 1 + 1 > 2 can be achieved through matched use. The high-efficiency composite flame retardant prepared by the preparation method disclosed by the invention is used as a flame retardant to be applied to a rubber and plastic foaming material, the limit oxygen index (LOI) and the vertical and horizontal combustion performance of a product are greatly improved, and the national standard B1-level flame retardant requirement can be met.

Description

Technical Field

[0001] This invention relates to a highly efficient and environmentally friendly flame retardant and its preparation method for use in the rubber and plastic foam industry. It relates to the field of flame retardant materials technology, and is particularly suitable for rubber and plastic foam materials with nitrile rubber as the base material. It can be widely used in flame retardant modification of central air conditioning pipes, building insulation, chemical containers, ships and vehicles. Background Technology

[0002] Fire is an extremely destructive disaster facing human society, causing not only enormous property damage but also claiming innocent lives. Every year, the world suffers a terrible price from fires, from destroyed homes, factories, and forests to countless families being torn apart; the threat of fire is ever-present. Flame retardants, as substances that can effectively delay or prevent the combustion of materials, play a crucial role in fire prevention and control systems, and there is a close and vital relationship between the two.

[0003] According to the national standards GB / T2406.2-2009 "Determination of Combustion Behavior of Plastics by Oxygen Index Method" and GB / T8333-2008 "Determination of Combustion Performance of Plastics by Vertical Method", rubber and plastic foam materials must meet the B1 flame retardant standard, with specific indicators as follows: Limiting Oxygen Index (LOI) ≥ 32.0%, burning time ≤ 30s, burning height ≤ 250mm, smoke density ≤ 75SDR, and meet the self-extinguishing requirement after flame removal. In existing technologies, single flame retardants are difficult to achieve the above indicators: halogenated flame retardants, although highly efficient, easily release toxic fumes; transition metal oxides have limited flame retardant effects when used alone; alkaline earth metal hydroxides require large doses to be effective, leading to a decrease in the material's mechanical properties; and borate compounds have poor charring effects when used alone.

[0004] Although existing research has attempted composite flame retardant systems, they generally suffer from problems such as unreasonable component matching and insignificant synergistic effects, resulting in low flame retardant efficiency, large addition amounts, and poor environmental performance. Therefore, developing a composite flame retardant with optimized component synergy, high flame retardant efficiency, excellent environmental performance, and the ability to meet the B1 flame retardant requirements for rubber and plastic foam materials, as well as its preparation method, has become a pressing technical challenge in this field. Summary of the Invention

[0005] The purpose of this invention is to provide a highly efficient and environmentally friendly flame retardant and its preparation method for use in the rubber and plastic foam industry. Addressing the technical shortcomings of existing flame retardants for rubber and plastic foam materials, such as low flame retardant efficiency, inability of single components to meet B1-level flame retardant requirements, insufficient synergistic effect of composite systems, and high combustion toxicity, this invention provides a highly efficient and environmentally friendly composite flame retardant with scientifically proportioned components and significant synergistic effects. Simultaneously, it provides a simple and highly controllable preparation method, achieving a precise improvement in the flame retardant performance of rubber and plastic foam materials.

[0006] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution: In a first aspect, the present invention is a highly efficient and environmentally friendly flame retardant for use in the rubber and plastic foaming industry. The flame retardant is composed of the following components by weight fraction: 25-40 parts of halogen compounds, 10-30 parts of transition metal oxides, 20-35 parts of alkaline earth metal hydroxides, and 25-45 parts of borate compounds.

[0007] The halogen compound is selected from one or more combinations of decabromodiphenyl ethane, chlorinated polyvinyl chloride, and bromotriazine.

[0008] The transition metal oxide is selected from one or more combinations of bismuth trioxide, zinc hydroxystannate, and antimony trioxide.

[0009] The alkaline earth metal hydroxide is selected from one or a combination of two of magnesium hydroxide and aluminum hydroxide.

[0010] The borate compounds are selected from one or a combination of two of zinc borate and barium metaborate.

[0011] Preferably, the halogen compound is a combination of decabromodiphenyl ethane and bromotriazine, with a weight ratio of 1:1 to 3:1.

[0012] Preferably, the transition metal oxide is a combination of bismuth trioxide and antimony trioxide, with a weight ratio of 1:1 to 2:1.

[0013] Preferably, the alkaline earth metal hydroxide is a combination of magnesium hydroxide and aluminum hydroxide, with a weight ratio of 2:1 to 3:1.

[0014] Preferably, the borate compound is a combination of zinc borate and barium metaborate, with a weight ratio of 3:1 to 4:1.

[0015] Secondly, a method for preparing the highly efficient and environmentally friendly flame retardant mentioned in the first aspect is provided, comprising the following steps: Step 1, Raw material pretreatment: a. Raw material selection: halogen compounds, transition metal oxides, alkaline earth metal hydroxides, and borate compounds are selected respectively.

[0016] b. Raw material crushing: The raw material is crushed to a particle size of 10-50μm using an air jet mill.

[0017] c. Drying: Dry the pulverized raw materials in an oven at 80-100℃ for 2-4 hours, controlling the moisture content of the raw materials to ≤0.5%.

[0018] Step 2, Mixing raw materials: a. Stirring: Add the pretreated components to the high-speed mixer according to their corresponding weight proportions, close the feed inlet, and start the equipment.

[0019] b. Mixing: First, premix at 500-800 rpm for 10-15 minutes, then heat to 80-120℃, adjust the speed to 900-1500 rpm, and continue stirring for 1-2 hours. During this period, turn on the stirrer every 20-30 minutes to reverse the direction of stirring for 3-5 minutes to ensure that the components are mixed evenly.

[0020] Step 3: Post-processing of finished products: a. After stopping the stirring during post-processing molding, allow the mixed powder to cool naturally to room temperature.

[0021] b. Sieve the material through a 200-300 mesh standard sieve and collect the undersize material, which is the high-efficiency and environmentally friendly composite flame retardant.

[0022] Preferably, the particle size of the raw material in step 1 is controlled to be 20-30 μm.

[0023] Preferably, the heating temperature in step 2 is 100-110℃ and the stirring speed is 1200-1500 rpm.

[0024] Preferably, the continuous stirring time in step 2 is 1.5 hours, the reverse stirring interval is 25 minutes, and the reverse stirring duration is 4 minutes.

[0025] Based on the above two aspects, preferably, the composite flame retardant is used in rubber and plastic foam materials.

[0026] The present invention has the following beneficial effects: (1) In this invention, a certain proportion of halogen compounds, transition metal oxides, alkaline earth metal hydroxides and borate compounds are poured into a high-speed stirrer and stirred and compounded at a certain temperature and speed. After the temperature is raised to a suitable temperature, the timer is started and the stirring is stopped after the time is reached. Finally, the flame retardant powder is added to the rubber-plastic foam material with nitrile rubber as the base material and corresponding samples are prepared to test its flame retardant performance.

[0027] (2) The particle size of each component of the composite flame retardant of the present invention is precisely controlled, and the interface compatibility with rubber and plastic substrates such as nitrile rubber and polyvinyl chloride resin is good. After addition, it will not cause a significant decrease in key mechanical properties such as tensile strength and elongation at break of the material. It can maintain the original softness, flexibility, shock absorption and sound absorption of the rubber and plastic foam material. It solves the industry pain point that the large dosage of traditional flame retardants leads to the brittleness and cracking of the material, and meets the requirements of central air conditioning pipes, vehicle interiors and other materials for material flexibility.

[0028] (3) The flame retardant powder of the present invention has excellent flowability. It will not agglomerate or clump during the entire process of mixing, open milling and vulcanization foaming of rubber and plastic materials. It can be evenly dispersed in the rubber system, effectively reducing processing defects such as uneven pores, local scorching and shrinkage deformation during foaming, reducing the scrap rate in the production process, and is compatible with the process parameters of existing rubber and plastic foaming production lines. No additional modification to the equipment is required.

[0029] (4) This invention forms a stable flame-retardant structure through the gas-phase synergy of halogen-transition metal oxides and the condensed phase synergy of alkaline earth metal hydroxide borates. Compared with the traditional single system, the flame retardant components do not migrate or precipitate during long-term use. The limiting oxygen index, vertical burning rating and other indicators of rubber and plastic products have a decay rate of ≤3%, and can maintain B1-level flame retardant performance for a long time. It is especially suitable for long-term service scenarios such as building insulation and ship pipelines.

[0030] (5) The optimized composition ratio of the present invention significantly reduces the amount of high-valent halogen compounds while ensuring flame retardant efficiency. At the same time, it reduces the total amount of flame retardant added through synergistic effect. The improved processing stability reduces production energy consumption and waste loss.

[0031] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0032] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a flowchart of the preparation method of the present invention. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Implementation Plan Please see Figure 1 As shown, this invention is a highly efficient and environmentally friendly flame retardant for use in the rubber and plastic foaming industry, and its preparation method.

[0036] In a first aspect, the present invention is a highly efficient and environmentally friendly flame retardant for use in the rubber and plastic foaming industry. The flame retardant is composed of the following components by weight fraction: 25-40 parts of halogen compounds, 10-30 parts of transition metal oxides, 20-35 parts of alkaline earth metal hydroxides, and 25-45 parts of borate compounds. The halogen compound is selected from one or more combinations of decabromodiphenyl ethane, chlorinated polyvinyl chloride, and bromotriazine, wherein the halogen compound is a combination of decabromodiphenyl ethane and bromotriazine, and the weight ratio of the two is 1:1 to 3:1. The transition metal oxide is selected from one or more combinations of bismuth trioxide, zinc hydroxystannate, and antimony trioxide, wherein the transition metal oxide is a combination of bismuth trioxide and antimony trioxide, and the weight ratio of the two is 1:1-2:1. The alkaline earth metal hydroxide is selected from one or a combination of magnesium hydroxide and aluminum hydroxide, wherein the alkaline earth metal hydroxide is a combination of magnesium hydroxide and aluminum hydroxide, and the weight ratio of the two is 2:1-3:1. The borate compound is selected from one or a combination of two of zinc borate and barium metaborate, wherein the borate compound is a combination of zinc borate and barium metaborate in a weight ratio of 3:1 to 4:1.

[0037] Secondly, this invention provides a method for preparing a highly efficient and environmentally friendly flame retardant for use in the rubber and plastic foaming industry, comprising the following steps: Step 1, Raw material pretreatment: a. Raw material selection: halogen compounds, transition metal oxides, alkaline earth metal hydroxides, and borate compounds are selected respectively; b. Raw material crushing: The raw material is crushed to a particle size of 10-50μm using an air jet mill; it should be noted that the particle size of the crushed raw material is controlled to be 20-30μm. c. Drying: Dry the pulverized raw materials in an oven at 80-100℃ for 2-4 hours, controlling the moisture content of the raw materials to ≤0.5%; Step 2, Mixing raw materials: a. Stirring: Add the pretreated components to the high-speed mixer according to their corresponding weight proportions, close the feed inlet, and start the equipment; b. Mixing: First, premix at 500-800 rpm for 10-15 minutes, then heat to 80-120℃, stirring at 1200-1500 rpm, then adjust the speed to 900-1500 rpm and continue stirring for 1-2 hours. During this period, turn on the stirrer every 20-30 minutes to reverse the direction of stirring for 3-5 minutes to ensure that the components are mixed evenly. The continuous stirring time is 1.5 hours, and the reverse stirring interval is 25 minutes. It should be noted that the heating temperature is 100-110℃ and the reverse stirring time is 4 minutes. Step 3: Post-processing of finished products: a. After stopping stirring during post-processing and molding, allow the mixed powder to cool naturally to room temperature; b. Sieve the material through a 200-300 mesh standard sieve and collect the undersize material, which is the high-efficiency and environmentally friendly composite flame retardant.

[0038] It should also be noted that composite flame retardants are used in rubber and plastic foam materials.

[0039] Example 1: 350g of decabromodiphenyl ethane, 100g of bismuth trioxide, 200g of magnesium hydroxide, and 350g of zinc borate were added to a small high-speed mixer and stirred at 900 rpm for 1.5 hours. After uniform mixing, the product was prepared according to the method in requirement 7, and its limiting oxygen index and vertical combustion performance were tested.

[0040] Example 2: 350g of chlorinated polyvinyl chloride, 100g of bismuth trioxide, 200g of magnesium hydroxide, and 350g of zinc borate were added to a small high-speed mixer and stirred at 900 rpm for 1.5 hours. After uniform mixing, the product was prepared according to the method in requirement 7, and its limiting oxygen index and vertical combustion performance were tested.

[0041] Example 3: 350g of triazine bromide, 100g of bismuth trioxide, 200g of magnesium hydroxide, and 350g of zinc borate were added to a small high-speed mixer and stirred at 900 rpm for 1.5 hours. After uniform mixing, the product was prepared according to the method in requirement 7, and its limiting oxygen index and vertical combustion performance were tested.

[0042] Example 4: 350g of decabromodiphenyl ethane, 100g of antimony trioxide, 200g of magnesium hydroxide, and 350g of zinc borate were added to a small high-speed mixer and stirred at 900 rpm for 1.5 hours. After uniform mixing, the product was prepared according to the method in requirement 7, and its limiting oxygen index and vertical combustion performance were tested.

[0043] Example 5: 350g of decabromodiphenyl ethane, 100g of antimony trioxide, 200g of aluminum hydroxide, and 350g of zinc borate were added to a small high-speed mixer and stirred at 900 rpm for 1.5 hours. After uniform mixing, the product was prepared according to the method in requirement 7, and its limiting oxygen index and vertical combustion performance were tested.

[0044] Example 6: 350g of decabromodiphenyl ethane, 100g of antimony trioxide, 200g of magnesium hydroxide, and 350g of barium metaborate were added to a small high-speed mixer and stirred at 900 rpm for 1.5 hours. After uniform mixing, the product was prepared according to the method in requirement 7, and its limiting oxygen index and vertical combustion performance were tested.

[0045] Example 7: 350g of decabromodiphenyl ethane, 100g of bismuth trioxide, 200g of magnesium hydroxide, and 350g of zinc borate were added to a small high-speed mixer and stirred at 1500 rpm for 1.5 hours. After uniform mixing, the product was prepared according to the method described in requirement 7, and its limiting oxygen index and vertical combustion performance were tested.

[0046] Comparative Example 1: Only decabromodiphenyl ethane was added to prepare the finished product according to the method in requirement 7, and its limiting oxygen index and vertical combustion performance were tested.

[0047] Comparative Example 2: Only brominated triazine was added to prepare the finished product according to the method in requirement 7, and its limiting oxygen index and vertical combustion performance were tested.

[0048] Comparative Example 3: Bismuth trioxide was added only and prepared as a finished product according to the method in requirement 7, and its limiting oxygen index and vertical combustion performance were tested.

[0049] Comparative Example 4: Antimony trioxide was added only and prepared as a finished product according to the method in requirement 7, and its limiting oxygen index and vertical combustion performance were tested.

[0050] Comparative Example 5: Magnesium hydroxide was added only and prepared as required in Requirement 7 to form a finished product, and its limiting oxygen index and vertical combustion performance were tested.

[0051] Comparative Example 6: Aluminum hydroxide was added only and the product was prepared according to the method in Requirement 7. Its limiting oxygen index and vertical combustion performance were then tested.

[0052] Comparative Example 7: Zinc borate was added only and prepared as a finished product according to the method in requirement 7, and its limiting oxygen index and vertical combustion performance were tested.

[0053] Comparative Example 8: Barium metaborate was added only and prepared as a finished product according to the method in requirement 7, and its limiting oxygen index and vertical combustion performance were tested.

[0054] Flame retardant performance test results of the samples Table 1 Test Results of Examples

[0055] Table 2 Comparative test results

[0056] Tables 1 and 2 clearly show that all single flame retardants lag significantly behind the composite flame retardant system in key indicators such as limiting oxygen index (LOI), UL-94 rating, and peak heat release rate (pHRR). This gap stems from the multi-stage and multi-phase coupling nature of polymer combustion, specifically: 1) A single component can often only play a role in a certain stage of the gas phase or condensed phase. Once that stage is breached, the flame retardant barrier will quickly fail.

[0057] 2) Composite flame retardants integrate functions such as gas phase capture, surface charring, oxygen isolation and heat insulation, and smoke suppression and neutralization into the same system through a multi-mechanism synergy and multi-barrier superposition strategy, forming a synergistic gain of 1+1>2.

[0058] Specifically, the combination of halogens (Br, Cl) with transition metal oxides (such as ZnO, CuO, Fe2O3) is a typical example of dual-target synergistic effect in gas-phase condensation, as follows: Halogens release HX and X· free radicals at high temperatures, which react with highly reactive free radicals such as HO· and H· generated by polymer thermal decomposition to terminate the chain, reducing the concentration of combustible gases. At the same time, transition metal oxides are reduced to low-valence metals or metal oxygen clusters, which further capture free radicals in the gas phase and form stable metal halide particles, which act as solid flame-retardant seeds and inhibit the continued combustion chain reaction.

[0059] This synergistic mechanism enables the system to reach V-0 levels with low halogen content, significantly reducing halogen usage and decreasing the release of fumes and corrosive gases. In terms of the condensed phase, the combination of borates (such as ZnB, CaB, BaB) with metal hydroxides (Al(OH)3, Mg(OH)2) offers the dual advantages of surface ceramicization and smoke suppression neutralization.

[0060] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A high-efficiency environmentally friendly flame retardant applied to the rubber and plastic foaming industry, characterized in that, The flame retardant is composed of the following weight fractions of components: halogen compound 25-40 parts, transition metal oxide 10-30 parts, alkaline earth metal hydroxide 20-35 parts, borate compound 25-45 parts; The halogen compound is selected from one or more than two combinations of decabromobiphenyl ethane, chlorinated polyvinyl chloride, bromine triazine; The transition metal oxide is selected from one or more than two combinations of bismuth trioxide, zinc hydroxystannate, antimony trioxide; The alkaline earth metal hydroxide is selected from one or more than two combinations of magnesium hydroxide, aluminum hydroxide; The borate compound is selected from one or more than two combinations of zinc borate, barium metaborate.

2. The high-efficiency environmentally friendly flame retardant applied to the rubber and plastic foaming industry according to claim 1, characterized in that, The halogen compound is a combination of decabromobiphenyl ethane and bromine triazine, and the weight fraction ratio of the two is 1:1-3:

1.

3. The high-efficiency environmentally friendly flame retardant applied to the rubber and plastic foaming industry according to claim 1, characterized in that, The transition metal oxide is a combination of bismuth trioxide and antimony trioxide, and the weight fraction ratio of the two is 1:1-2:

1.

4. The high-efficiency environmentally friendly flame retardant applied to the rubber and plastic foaming industry according to claim 1, characterized in that, The alkaline earth metal hydroxide is a combination of magnesium hydroxide and aluminum hydroxide, and the weight fraction ratio of the two is 2:1-3:

1.

5. The high-efficiency environmentally friendly flame retardant applied to the rubber and plastic foaming industry according to claim 1, characterized in that, The borate compound is a combination of zinc borate and barium metaborate, and the weight fraction ratio of the two is 3:1-4:

1.

6. A method for preparing a high-efficiency environmentally friendly flame retardant applied to the rubber and plastic foaming industry, which is used for preparing a high-efficiency environmentally friendly flame retardant applied to the rubber and plastic foaming industry according to any one of claims 1-5, characterized in that, The following steps are included: Step 1, raw material pretreatment: a. Raw material selection, respectively select halogen compound, transition metal oxide, alkaline earth metal hydroxide and borate compound; b. Raw material crushing, crushing to a particle size of 10-50 μm by air jet mill; c. Drying, drying the crushed raw materials in an oven at 80-100 ℃ for 2-4 h, controlling the water content of the raw materials ≤0.5%; Step 2, raw material mixing: a. Stirring, after pretreatment, each component is put into a high-speed stirrer according to the corresponding weight fraction, the feeding port is closed and the equipment is started; b. Mixing, first pre-mixing at 500-800 rpm for 10-15 min, then heating to 80-120 ℃, adjusting the speed to 900-1500 rpm, continuous stirring for 1-2 h, during which the stirring paddle is reversed every 20-30 min for 3-5 min to ensure uniform mixing of the components; Step 3, post-processing finished product: a. After stopping stirring, the mixed powder is naturally cooled to room temperature; b. Screened through a 200-300 mesh standard screen, collecting the undersize, which is the high-efficiency environmentally friendly composite flame retardant.

7. The method according to claim 6, characterized in that, The crushing particle size of the raw materials in step 1 is controlled to be 20-30 μm.

8. The method according to claim 6, characterized in that, The temperature in step 2 is 100-110 ℃, and the stirring speed is 1200-1500 rpm.

9. The method according to claim 6, characterized in that, The continuous stirring time in step 2 is 1.5 h, and the reverse stirring interval is 25 min, and the reverse stirring time is 4 min.

10. A high efficiency environmentally friendly flame retardant for use in the rubber and plastics foaming industry as claimed in any one of claims 1 to 5 and a process for the preparation of a high efficiency environmentally friendly flame retardant for use in the rubber and plastics foaming industry as claimed in any one of claims 6 to 9, characterized in that, The composite flame retardant is applied in rubber and plastic foaming materials.

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