Environment-friendly flame-retardant ABS resin and preparation method thereof

Abstract

The invention relates to the technical field of resin, and discloses environment-friendly flame-retardant ABS (acrylonitrile-butadiene-styrene) resin and a preparation method thereof.The ABS resin is prepared by taking ABS resin as a base material and a halogen-free phosphorus-containing flame retardant, a fiber-reinforced modified material and the like as auxiliary materials through mixing and extrusion processes, the phosphorus-heterobicyclic structure in the cross-linked intermediate structure can be used as an acid source, and can quickly form a compact carbon layer on the surface of the resin when combustion occurs, so that oxygen and heat can be isolated, and the melting and dripping phenomenon generated by resin combustion can be prevented, thereby effectively improving the flame retardant property of the resin and prolonging the service life of the resin. And the mechanical strength of the resin can be effectively improved by adding the fiber-reinforced modified material. In addition, the polysilazane structure contains silicon and nitrogen flame-retardant elements, so that a halogen-free phosphorus-containing flame retardant can be assisted, the strength and the heat-insulating and oxygen-isolating effects of a carbon layer are improved, and the flame-retardant property of the resin is further enhanced.

Description

Technical Field

[0001] The invention relates to the technical field of resins, and in particular to an environmentally friendly flame-retardant ABS resin and a preparation method thereof. Background Art

[0002] ABS resin (acrylonitrile-butadiene-styrene) is a widely used thermoplastic. Due to its excellent processing properties, good mechanical strength and surface gloss, it is widely used in many fields such as automobile manufacturing, electronic equipment, and building materials. However, the flame retardant properties of ABS resin are poor, and the limiting oxygen index is low, usually between 18.3% and 20%, which is a flammable polymer material. Its horizontal burning speed is fast, about 25 to 51 mm / min, and it is not easy to extinguish. During the combustion process, a large amount of thick yellow-black smoke and toxic gases are released, which not only poses a great safety hazard, but also causes environmental pollution. In addition, the mechanical strength of ABS resin is gradually unable to meet the use requirements of some industries. These defects have greatly limited the application of ABS resin in some fields, especially in the electrical industry. This characteristic of ABS resin makes it difficult to promote.

[0003] In order to improve the comprehensive performance of ABS resin, it is generally modified by using a blending method of functional additives, such as inorganic flame retardants such as aluminum hydroxide and magnesium hydroxide, or halogen flame retardants such as tetrabromobisphenol A, etc. However, the flame retardant modification effect of inorganic flame retardants themselves is poor, and a large amount of addition is required, which will affect the mechanical strength of ABS resin. Halogen flame retardants will produce a large amount of toxic and harmful gases when burned, which will cause great environmental pollution. Therefore, they all have obvious defects. Organic phosphorus flame retardants have excellent flame retardant effects and will not cause environmental pollution. Therefore, they have been widely used in recent years. However, phosphorus flame retardants are easy to volatilize and migrate, making it difficult to ensure the continuous flame retardancy of the resin.

[0004] Based on this, the present invention provides an environmentally friendly flame-retardant ABS resin, which can solve the problems existing in the prior art. Summary of the invention

[0005] 1. Technical issues to be resolved

[0006] In view of the deficiencies in the prior art, the present invention provides an environmentally friendly flame-retardant ABS resin and a preparation method thereof.

[0007] (II) Technical solution

[0008] A method for preparing an environmentally friendly flame-retardant ABS resin, wherein the environmentally friendly flame-retardant ABS resin is prepared by using the following raw materials measured in parts by weight:

[0009]

[0010] The preparation method comprises the following steps:

[0011] The first step is to weigh each raw material according to weight and set aside;

[0012] The second step is to add the raw materials prepared in the first step into a high-speed mixer, stir and mix them evenly at a stirring rate of 1000-1500r / min, and then feed them into a twin-screw extruder, control the extrusion temperature to 200-230°C, and the screw speed to 200-300r / min, and then obtain environmentally friendly flame-retardant ABS resin through a melt extrusion process;

[0013] The fiber-reinforced modified material is flax fiber with polysilazane coated on the surface.

[0014] Preferably, the specific preparation method of the halogen-free phosphorus-containing flame retardant comprises the following steps:

[0015] Step 1, add 2,3-dibromosuccinic acid, 2,6,7-trioxa-1-phosphabicyclo (2.2.2) octane-4-methanol-1-oxide and toluene into a reaction kettle, start stirring, and after a uniform solution is formed, continue to add an aqueous sodium hydroxide solution. After the addition is completed, raise the temperature to 60-70°C, keep stirring for 2-4 hours, evaporate the solvent, cool and discharge the material to obtain a cross-linked intermediate;

[0016] Step 2: Add maltose to an ethanol solution with a volume fraction of 60-70%, stir and mix evenly, then add a cross-linking intermediate and a phase transfer catalyst. After adding, continue to increase the temperature to 80-90°C, reflux and stir for 12-16 hours, stop heating, cool and discharge the material, wait for natural cooling to form a gel material, transfer it to a freeze dryer, freeze-dry it at -50°C for 24-48 hours, take it out, and crush it to obtain a halogen-free phosphorus-containing flame retardant.

[0017] Preferably, in step 1, the molar ratio of 2,3-dibromosuccinic acid to 2,6,7-trioxa-1-phosphabicyclo(2.2.2)octane-4-methanol-1-oxide is 1:1-2.

[0018] Preferably, in step 1, the mass fraction of the sodium hydroxide aqueous solution is 15-25%.

[0019] Preferably, in step 2, the phase transfer catalyst is p-toluenesulfonic acid or trifluoromethanesulfonic acid.

[0020] In the above technical scheme, 2,3-dibromosuccinic acid and 2,6,7-trioxa-1-phosphabicyclo (2.2.2) octane-4-methanol-1-oxide are first used as reactants. Under the action of sodium hydroxide, the halogen substituents and active hydroxyl substituents in each other's structures can undergo substitution reactions to obtain a disubstituted carboxyl derivative containing a phosphorus-containing bicyclo flame retardant structure, i.e., a cross-linking intermediate. Then, under the action of a phase transfer catalyst, it can undergo continuous condensation reactions with the substituted hydroxyl groups in the maltose structure, thereby cross-linking the maltose. Finally, through freeze-drying treatment, an aerogel-type halogen-free phosphorus-containing flame retardant based on maltose is obtained.

[0021] Preferably, the specific preparation method of the fiber-reinforced modified material comprises the following steps:

[0022] Step A, ultrasonically dispersing the alkalized flax fiber in an ethanol solution with a volume fraction of 70-80%, then adding γ-glycidyloxypropyltriethoxysilane to the formed ultrasonic liquid material, after the addition, gradually raising the temperature to 70-80° C., keeping the temperature and stirring for 6-9 hours, then cooling and discharging the material to obtain modified flax fiber;

[0023] Step B: Add the modified flax fiber to 1,4-dioxane, and after uniform dispersion, continue to add polysilazane. After the addition is completed, increase the temperature to 60-70° C., keep stirring for 4-8 hours, cool down and discharge the material to obtain a fiber-reinforced modified material.

[0024] Preferably, in step A, the alkali treatment method of the flax fiber is: immerse the flax fiber with a length of 1 mm in a sodium hydroxide solution with a mass fraction of 15-25%, soak it at 50-55° C. for 3-6 hours, then take it out, wash it to neutrality, and then vacuum dry it.

[0025] Preferably, in step B, the number average molecular weight of the polysilazane is 1000.

[0026] In the above technical scheme, the flax fiber is firstly subjected to an alkalization treatment to expose a large number of hydroxyl oxygen-containing functional groups on its surface, and then its surface is modified using γ-glycidyloxypropyltriethoxysilane to obtain a modified flax fiber, the epoxy groups on its surface can undergo a ring-opening addition reaction with the secondary amine groups in the polysilazane structure, thereby coating the surface of the flax fiber with polysilazane to obtain a fiber-reinforced modified material.

[0027] Preferably, the inorganic filler is at least one of talc, titanium dioxide or carbon black; the antioxidant is a hindered phenol antioxidant or a phosphite antioxidant; and the lubricant is at least one of polyethylene wax, paraffin or calcium stearate.

[0028] An environmentally friendly flame-retardant ABS resin is prepared by adopting the preparation method.

[0029] (III) Beneficial technical effects

[0030] (1) The present invention prepares an aerogel-type halogen-free phosphorus-containing flame retardant based on maltose to modify ABS resin. First, the maltose in the structure of the halogen-free phosphorus-containing flame retardant can be used as a carbon source, and the phosphorus heterobicyclic structure in the cross-linked intermediate structure can be used as an acid source. When combustion occurs, it can quickly form a dense carbon layer on the surface of the resin, which can not only isolate oxygen and heat, but also prevent the melting dripping phenomenon caused by the combustion of the resin, thereby effectively improving the flame retardant properties of the resin. At the same time, the porous structure of the aerogel can absorb the smoke generated by the combustion, thereby producing a certain environmental protection effect.

[0031] (2) The present invention obtains a fiber-reinforced modified material by coating the surface of flax fiber with polysilazane. On the one hand, the presence of polysilazane is equivalent to generating a layer of organic transition structure between the flax fiber and the ABS resin, which greatly enhances the interfacial affinity between them, thereby enabling the flax fiber to efficiently play its role as a fiber reinforcing agent and improve the mechanical strength of the resin. In addition, since the polysilazane structure contains silicon and nitrogen flame retardant elements, it can assist the halogen-free phosphorus-containing flame retardant to improve the strength and heat insulation and oxygen isolation effects of the carbon layer, and further enhance the flame retardant properties of the resin. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0033] Figure 1 This is a scanning electron microscope image of a halogen-free phosphorus-containing flame retardant. DETAILED DESCRIPTION

[0034] In order to facilitate the understanding of the present invention, the present invention will be described more fully below. Preferred embodiments of the present invention are given below. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0035] Preparation Example 1

[0036] Preparation of halogen-free phosphorus-containing flame retardant:

[0037] Step 1, add 0.8 g of 2,3-dibromosuccinic acid, 0.5 g of 2,6,7-trioxa-1-phosphabicyclo (2.2.2) octane-4-methanol-1-oxide and toluene into a reaction kettle, start stirring, and after a uniform solution is formed, continue to add 10 mL of a 20% by mass sodium hydroxide aqueous solution. After the addition is completed, the temperature is raised to 65° C., and after stirring for 3 hours, the solvent is evaporated and removed, and the temperature is lowered and the material is discharged to obtain a cross-linked intermediate;

[0038] Step 2: Add 1.2 g of maltose to a 60% ethanol solution by volume, stir to mix evenly, then add 0.3 g of a cross-linked intermediate and 0.01 g of p-toluenesulfonic acid. After the addition, continue to raise the temperature to 90°C, reflux and stir for 15 hours, stop heating, cool and discharge the material, wait for it to cool naturally to form a gel, transfer it to a freeze dryer, freeze-dry it at -50°C for 48 hours, take it out, and crush it to obtain a halogen-free phosphorus-containing flame retardant.

[0039] Figure 1 This is a scanning electron microscope image of a halogen-free phosphorus-containing flame retardant. It is observed that it has an obvious pore structure, and the pore structure is relatively uniform. It has the special morphology of aerogel and can absorb the smoke produced by combustion.

[0040] Preparation Example 2

[0041] Preparation of fiber reinforced modified materials:

[0042] Step A, immersing 4 g of flax fiber with a length of 1 mm in 100 mL of a 20% sodium hydroxide solution at 50° C. for 4 hours, taking it out, washing it to neutrality, and then vacuum drying it to obtain alkalized flax fiber;

[0043] Step B, ultrasonically dispersing 2.2 g of alkalized flax fiber in a 70% by volume ethanol solution, then adding 3.5 g of γ-glycidyloxypropyltriethoxysilane to the formed ultrasonic liquid material, and after the addition, gradually raising the temperature to 75° C., stirring at the temperature for 8 hours, cooling and discharging the material to obtain modified flax fiber;

[0044] Step C: add 1.8 g of modified flax fiber to 1,4-dioxane, and after uniform dispersion, continue to add 1.5 g of polysilazane with a number average molecular weight of 1000. After the addition is completed, raise the temperature to 65° C., keep stirring for 6 hours, cool and discharge the material to obtain a fiber-reinforced modified material.

[0045] Example 1

[0046] An environmentally friendly flame-retardant ABS resin is made from the following raw materials measured in parts by weight:

[0047]

[0048] The preparation method of the environmentally friendly flame-retardant ABS resin comprises the following steps:

[0049] The first step is to weigh each raw material according to weight and set aside;

[0050] In the second step, the raw materials prepared in the first step are added into a high-speed mixer, and after being mechanically stirred and mixed evenly at a stirring rate of 1000r / min, they are fed into a twin-screw extruder, and the extrusion temperature is controlled at 200°C and the screw speed is 200r / min. After the melt extrusion process, the environmentally friendly flame-retardant ABS resin can be obtained.

[0051] The preparation method of the halogen-free phosphorus-containing flame retardant is shown in Preparation Example 1; the preparation method of the fiber-reinforced modified material is shown in Preparation Example 2, and the following are the same.

[0052] Example 2

[0053] An environmentally friendly flame-retardant ABS resin is made from the following raw materials measured in parts by weight:

[0054]

[0055] The preparation method of the environmentally friendly flame-retardant ABS resin comprises the following steps:

[0056] The first step is to weigh each raw material according to weight and set aside;

[0057] In the second step, the raw materials prepared in the first step are added into a high-speed mixer, and after being mechanically stirred and mixed evenly at a stirring rate of 1200r / min, they are fed into a twin-screw extruder, and the extrusion temperature is controlled at 220°C and the screw speed is 300r / min. After the melt extrusion process, the environmentally friendly flame-retardant ABS resin can be obtained.

[0058] Example 3

[0059] An environmentally friendly flame-retardant ABS resin is made from the following raw materials measured in parts by weight:

[0060]

[0061] The preparation method of the environmentally friendly flame-retardant ABS resin comprises the following steps:

[0062] The first step is to weigh each raw material according to weight and set aside;

[0063] In the second step, the raw materials prepared in the first step are added into a high-speed mixer, and after being mechanically stirred and mixed evenly at a stirring rate of 1500r / min, they are fed into a twin-screw extruder, and the extrusion temperature is controlled at 230°C and the screw speed is 300r / min. After the melt extrusion process, the environmentally friendly flame-retardant ABS resin can be obtained.

[0064] Comparative Example 1

[0065] An environmentally friendly flame-retardant ABS resin is made from the following raw materials measured in parts by weight:

[0066]

[0067] The preparation method of the environmentally friendly flame-retardant ABS resin comprises the following steps:

[0068] The first step is to weigh each raw material according to weight and set aside;

[0069] In the second step, the raw materials prepared in the first step are added into a high-speed mixer, and after being mechanically stirred and mixed evenly at a stirring rate of 1200r / min, they are fed into a twin-screw extruder, and the extrusion temperature is controlled at 220°C and the screw speed is 300r / min. After the melt extrusion process, the environmentally friendly flame-retardant ABS resin can be obtained.

[0070] Comparative Example 2

[0071] An environmentally friendly flame-retardant ABS resin is made from the following raw materials measured in parts by weight:

[0072]

[0073] The preparation method of the environmentally friendly flame-retardant ABS resin comprises the following steps:

[0074] The first step is to weigh each raw material according to weight and set aside;

[0075] In the second step, the raw materials prepared in the first step are added into a high-speed mixer, and after being mechanically stirred and mixed evenly at a stirring rate of 1200r / min, they are fed into a twin-screw extruder, and the extrusion temperature is controlled at 220°C and the screw speed is 300r / min. After the melt extrusion process, the environmentally friendly flame-retardant ABS resin can be obtained.

[0076] Comparative Example 3

[0077] An environmentally friendly flame-retardant ABS resin is made from the following raw materials measured in parts by weight:

[0078]

[0079] The preparation method of the environmentally friendly flame-retardant ABS resin comprises the following steps:

[0080] The first step is to weigh each raw material according to weight and set aside;

[0081] In the second step, the raw materials prepared in the first step are added into a high-speed mixer, and after being mechanically stirred and mixed evenly at a stirring rate of 1200r / min, they are fed into a twin-screw extruder, and the extrusion temperature is controlled at 220°C and the screw speed is 300r / min. After the melt extrusion process, the environmentally friendly flame-retardant ABS resin can be obtained.

[0082] Test Case

[0083] The ABS resins in the embodiments and comparative examples were made into test samples that met the specifications, and the tensile strength test was performed according to the standard GB / T1040.1-2018; the impact strength test was performed according to the standard GB / T 1843-2008; the limiting oxygen index test was performed according to the standard GB / T 2406.1-2008, and the test results were recorded in the following table:

[0084] Table 1 - Test results

[0085] Tensile strength / MPa <![CDATA[Impact strength / kJ / m 2 > Limiting oxygen index / % Example 1 41.4 13.2 31.7 Example 2 41.8 13.4 32.0 Example 3 41.5 13.3 31.7 Comparative Example 1 41.2 13.0 21.9 Comparative Example 2 34.5 11.8 31.2 Comparative Example 3 28.7 9.4 29.6

[0086] Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core ideas, including the best mode, and also enable any technician in the field to practice the present invention, including making and using any device or system, and implementing any combined method. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, the present invention can also be improved and modified, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. The scope of patent protection of the present invention is defined by the claims and may include other embodiments that can be thought of by those skilled in the art. If these other embodiments have structural elements similar to the literal expression of the claims, or if they include equivalent structural elements that are not substantially different from the literal expression of the claims, then these other embodiments should also be included in the scope of the claims.

Claims

1. A method for preparing an environmentally friendly flame-retardant ABS resin, characterized in that: The environmentally friendly flame-retardant ABS resin is made of the following raw materials measured in parts by weight: The preparation method comprises the following steps: The first step is to weigh each raw material according to weight and set aside; The second step is to add the raw materials prepared in the first step into a high-speed mixer, stir and mix them evenly at a stirring rate of 1000-1500r / min, and then feed them into a twin-screw extruder, control the extrusion temperature to 200-230°C, and the screw speed to 200-300r / min, and then obtain environmentally friendly flame-retardant ABS resin through a melt extrusion process; The fiber-reinforced modified material is flax fiber with polysilazane coated on the surface.

2. The method for preparing an environmentally friendly flame-retardant ABS resin according to claim 1, characterized in that: The specific preparation method of the halogen-free phosphorus-containing flame retardant comprises the following steps: Step 1, add 2,3-dibromosuccinic acid, 2,6,7-trioxa-1-phosphabicyclo (2.2.2) octane-4-methanol-1-oxide and toluene into a reaction kettle, start stirring, and after a uniform solution is formed, continue to add an aqueous sodium hydroxide solution. After the addition is completed, raise the temperature to 60-70°C, keep stirring for 2-4 hours, evaporate the solvent, cool and discharge the material to obtain a cross-linked intermediate; Step 2: Add maltose to an ethanol solution with a volume fraction of 60-70%, stir and mix evenly, then add a cross-linking intermediate and a phase transfer catalyst. After adding, continue to increase the temperature to 80-90°C, reflux and stir for 12-16 hours, stop heating, cool and discharge the material, wait for natural cooling to form a gel material, transfer it to a freeze dryer, freeze-dry it at -50°C for 24-48 hours, take it out, and crush it to obtain a halogen-free phosphorus-containing flame retardant.

3. The method for preparing an environmentally friendly flame-retardant ABS resin according to claim 2, characterized in that: In the step 1, the molar ratio of 2,3-dibromosuccinic acid to 2,6,7-trioxa-1-phosphabicyclo (2.2.2) octane-4-methanol-1-oxide is 1:1-2.

4. The method for preparing an environmentally friendly flame-retardant ABS resin according to claim 2, characterized in that: In the step 1, the mass fraction of the sodium hydroxide aqueous solution is 15-25%.

5. The method for preparing an environmentally friendly flame-retardant ABS resin according to claim 2, characterized in that: In the step 2, the phase transfer catalyst is p-toluenesulfonic acid or trifluoromethanesulfonic acid.

6. The method for preparing an environmentally friendly flame-retardant ABS resin according to claim 1, characterized in that: The specific preparation method of the fiber-reinforced modified material comprises the following steps: Step A, ultrasonically dispersing the alkalized flax fiber in an ethanol solution with a volume fraction of 70-80%, then adding γ-glycidyloxypropyltriethoxysilane to the formed ultrasonic liquid material, after the addition, gradually raising the temperature to 70-80° C., keeping the temperature and stirring for 6-9 hours, then cooling and discharging the material to obtain modified flax fiber; Step B: Add the modified flax fiber to 1,4-dioxane, and after uniform dispersion, continue to add polysilazane. After the addition is completed, increase the temperature to 60-70° C., keep stirring for 4-8 hours, cool down and discharge the material to obtain a fiber-reinforced modified material.

7. The method for preparing an environmentally friendly flame-retardant ABS resin according to claim 6, characterized in that: In step A, the alkali treatment method of the flax fiber is: immerse the flax fiber with a length of 1 mm in a sodium hydroxide solution with a mass fraction of 15-25%, soak it at 50-55° C. for 3-6 hours, then take it out, wash it to neutrality, and then vacuum dry it.

8. The method for preparing an environmentally friendly flame-retardant ABS resin according to claim 6, characterized in that: In the step B, the number average molecular weight of the polysilazane is 1000.

9. The method for preparing an environmentally friendly flame-retardant ABS resin according to claim 1, characterized in that: The inorganic filler is at least one of talcum powder, titanium dioxide or carbon black; the antioxidant is a hindered phenol antioxidant or a phosphite antioxidant; and the lubricant is at least one of polyethylene wax, paraffin or calcium stearate.

10. An environmentally friendly flame-retardant ABS resin, characterized in that: The method is prepared according to any one of claims 1 to 9.

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