Functionalized black talc filled EVA composite material and preparation method thereof

Abstract

The invention provides a functionalized black talc filled EVA material and a preparation method thereof. EVA, functionalized black talc powder and an auxiliary agent in a mass ratio of 100: (1-30): (0.5-1.8) are uniformly mixed in a high-speed stirrer, melt extrusion is performed in a twin-screw extruder at the temperature of 120-170 DEG C, cooling, pelletizing and drying are performed, and the functionalized black talc filled EVA composite material is prepared, the auxiliary agent is a mixture of zinc stearate, a grafting initiator and an antioxidant 1010 in a mass ratio of (0.2-1): (0.2-0.5): (0.1-0.3); the preparation method comprises the following steps: firstly, modifying black talcum powder by using tetraethoxysilane, introducing a large number of functional sites on the surface of the black talcum powder, then modifying organosilane containing unsaturated functional groups again, and introducing the unsaturated functional groups as a connecting bridge with a matrix. The agglomeration phenomenon of original black talcum powder in a polymer matrix is effectively reduced, and the modified material has good dispersity.

Description

Technical Field

[0001] The present invention belongs to the technical field of mineral material processing and relates to a preparation method of a functionalized black talc filled EVA composite material. Background Art

[0002] EVA is a random copolymer of ethylene and vinyl acetate. The introduction of polar acetate groups into the ethylene chain forms short side chains, changing the original crystalline state and making EVA more flexible and elastic than polyethylene. EVA resin has a wide range of applications. Among them, the production process of EVA has a decisive impact on the performance and uses of the product. EVA with a low VAc content is similar to LDPE, being soft and having good impact strength, and is easy to manufacture heavy-duty packaging and composite materials. EVA with a VAc content of 10% - 20% has good transparency and is suitable for making agricultural films and shrink packaging films. EVA with a higher VAc content can be used as adhesives, coatings, paints, and can also be made into EVA foam plastics, electrical appliances, cable insulation layers, and daily necessities, etc.

[0003] Substances added to improve the specific molding and processing properties of plastics, enhance the mechanical properties of plastic products, or reduce the production cost of materials are called fillers. After being compounded and modified with specific polymer materials, the performance will be greatly improved. The types of fillers for EVA plastics are still being continuously developed and improved. At present, there are still many problems that cannot be completely solved in the filling and modification methods, such as how to greatly improve the dispersion of fillers in the polymer network and how to make the two have better interfacial bonding strength. The solution of these problems helps to further improve the various properties of EVA plastics and other filled composite materials.

[0004] The main mineral material of black talc is talc, which is a magnesium-rich silicate mineral. It has a flaky structure and a slippery feel, no water between layers, no odor, stable chemical properties, small particles, and a large specific surface area. Black talc is similar to talc in chemical and physical properties and has characteristics such as high thermal stability, strong adsorption, low thermal conductivity, hydrophobicity, high specific surface area and rheology, and excellent lubricity. The black talc industry is a raw material industry that has developed in recent years and has been widely used in the domestic ceramic industry and as fillers.

[0005] Currently, fillers used in EVA materials include hydrotalcite, magnesium hydroxide, silicon dioxide, etc., which have different beneficial effects on the properties of EVA materials such as tensile properties and processing fluidity. The types of fillers are still increasing, but the problems of filler dispersion in the matrix and its compatibility still exist. The solution of these problems will be beneficial to improving the performance of EVA. Summary of the Invention

[0006] The object of the present invention is to solve the problem of poor dispersion and compatibility of fillers in the EVA matrix. The primary object of the present invention is to provide a preparation method of a functionalized black talc-filled EVA material. The obtained composite material has the advantages of good thermal stability, excellent mechanical properties, and low cost.

[0007] Another object of the present invention is to provide an EVA composite material. Using black talc as the raw material and organosilane as the modifier, organically functionalized black talc powder is prepared by wet modification to improve dispersion and compatibility; the modified powder is melt-mixed with EVA and additives in a certain proportion, and the modified powder is grafted onto the EVA chain under the action of a peroxide grafting agent to further improve compatibility, obtaining an EVA composite material.

[0008] To achieve the above objects of the present invention, the following technical solutions are adopted:

[0009] The present invention provides a preparation method of a functionalized black talc-filled EVA material. EVA, functionalized black talc powder, and additives with a mass ratio of 100:1-30:0.5-1.8 are mixed evenly in a high-speed mixer, and then melt-extruded, cooled, pelletized, and dried at a temperature of 120-170 °C in a twin-screw extruder; the additives are a mixture of zinc stearate, grafting initiator, and antioxidant 1010 with a mass ratio of 0.2-1:0.2-0.5:0.1-0.3; the functionalized black talc powder is prepared as follows:

[0010] (1) Immerse black talc powder (less than 200 mesh) in a hydrochloric acid solution of 2-8 M (preferably 4-6 M, more preferably 4 M), stir at 55-85 °C for 6-8 h (preferably stir at 80 °C for 6 h) to obtain a first mixed solution, filter to remove the filtrate, wash with deionized water until the pH is neutral, dry (dry at 50-80 °C for 24 h), grind, and pass through a 200-mesh sieve to obtain pretreated black talc powder;

[0011] (2) Immerse the pretreated black talc powder obtained in step (1) in an ethanol aqueous solution with a mass concentration of 40%-60% (preferably 40%) to obtain a second mixed solution, adjust the pH to 4-6 (preferably pH = 5) with hydrochloric acid and stir evenly to obtain a suspension;

[0012] (3) Add tetraethyl orthosilicate and organosilane to the suspension described in step (2) in sequence, stir at 45 - 70 °C for 6 - 8 h (preferably stir at 60 °C for 6 h), then filter to remove the filtrate, wash with absolute ethanol, dry (dry at 50 - 80 °C for 24 h, preferably dry at 60 °C for 24 h), grind, and sieve to obtain functionalized black talc powder; the volume of the tetraethyl orthosilicate is 0.5 - 1 ml / g based on the mass of the pretreated black talc powder contained in the suspension; the volume of the organosilane is 0.5 - 1 ml / g based on the mass of the pretreated black talc powder contained in the suspension.

[0013] Further, the volume of the hydrochloric acid solution in step (1) is 5 ml / g - 20 ml / g (preferably 10 ml / g) based on the mass of the black talc powder.

[0014] Further, the volume of the ethanol aqueous solution in step (2) is 10 ml / g - 20 ml / g (preferably 10 ml / g) based on the mass of the pretreated black talc powder.

[0015] Further, the organosilane in step (3) is one or more of vinyltrimethoxysilane, vinyltriethoxysilane, isopropyl tris(dioctylpyrophosphate) titanate, or γ-methacryloxypropyltrimethoxysilane.

[0016] Further, the volume of the tetraethyl orthosilicate contained in the suspension in step (3) is 1 ml / g based on the mass of the pretreated black talc powder contained in the suspension; the volume of the organosilane is 0.5 ml / g based on the mass of the pretreated black talc powder contained in the suspension.

[0017] Further, the grafting initiator is one or more of cumene hydroperoxide, dicumyl peroxide, or 2,5-dimethyl-2,5-di-tert-butylperoxyhexane.

[0018] Further, the mass ratio of EVA, functionalized black talc powder, and additive is 100:10:1.2.

[0019] Further, the grafting initiator is dicumyl peroxide, and the mass ratio of zinc stearate, grafting initiator, and antioxidant 1010 is 0.5:0.5:0.2.

[0020] Further, the black talc powder is prepared by the following method:

[0021] Take black talc ore for preliminary crushing, place the black talc in an ethanol aqueous solution with a volume concentration of 50%, wet ball mill at 600 - 1000 r / min for 8 - 10 h, centrifuge the obtained product, wash with deionized water, dry, grind, and sieve through a 200-mesh sieve to obtain the black talc powder.

[0022] Another object of the present invention is to provide a functionalized black talc-filled EVA composite material obtained by the above preparation method of the present invention. This material makes EVA more flexible and elastic than polyethylene.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] (1) First, tetraethyl orthosilicate is used to modify the black talc powder in the present invention, introducing a large number of functional sites on its surface, and then an organosilane containing unsaturated functional groups is used for modification again, introducing unsaturated functional groups as a bridge connecting with the matrix. The agglomeration phenomenon of the original black talc powder in the polymer matrix is effectively reduced, and the modified material has good dispersibility.

[0025] (2) The introduction of vinyl unsaturated functional groups reacts with the polymer EVA matrix under the action of a peroxide graft initiator to form new chemical bonds, promoting the compatibility between the powder and the matrix.

[0026] (3) The preparation process of the present invention is simple, using black talc as a carrier, so that the product can reduce the production cost while maintaining good performance. Description of the Drawings

[0027] Figure 1 The physical picture of the composite material (functionalized black talc-filled EVA composite material) in Example 1.

[0028] Figure 2 The physical picture of the 1B type dumbbell-shaped specimen of the composite material in Example 1. Detailed Embodiments

[0029] The following will describe the implementation scheme of the present invention in detail in combination with examples. However, those skilled in the art will understand that the following examples are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. For those conditions not specified in the examples, they are carried out according to the conventional conditions or the conditions recommended by the manufacturer. For the reagents or instruments whose manufacturers are not specified, they are all conventional products that can be obtained through commercial purchase.

[0030] Mechanical property test:

[0031] The tensile properties are measured on an electronic universal testing machine according to GB / T 1040.1—2018. Five specimens in each specimen bag are taken for testing, and their average values are taken.

[0032] Example 1:

[0033] Take the black talc ore for preliminary crushing. Place the black talc in an ethanol aqueous solution with a volume concentration of 50%, and wet ball-mill it at 1000 r / min for 10 h. After taking out the obtained product, wash it repeatedly by centrifugation and deionized water, dry it, grind it through a 200-mesh sieve to obtain the required 200-mesh black talc powder. Put 30 g of the black talc powder into 300 ml of 4 mol / L hydrochloric acid solution for pretreatment under the condition of stirring at 80 °C for 6 h. Filter the obtained mixed solution (the first mixed solution), wash it with deionized water until the pH is neutral, dry it (dry at 70 °C for 24 h), grind it, and pass it through a 200-mesh sieve to obtain 28.6 g of pretreated black talc powder; then immerse 25 g of the pretreated black talc powder in 250 ml of 40% ethanol aqueous solution to obtain a second mixed solution. Adjust the pH to 5 with hydrochloric acid, stir and ultrasonically homogenize it at room temperature to obtain a suspension. Add tetraethyl orthosilicate and vinyltrimethoxysilane in sequence. The dosages of the pretreated black talc powder, tetraethyl orthosilicate, and vinyltrimethoxysilane are 25 g, 25 ml, and 12.5 ml respectively. Stir at 60 °C for 6 h. Filter the obtained mixed solution, wash it three times with absolute ethanol, dry it at 60 °C for 24 h, grind it, and pass it through a 200-mesh sieve to obtain 26.2 g of the functionalized black talc powder;

[0034] According to the following masses: 500 g of EVA, 5 g of the functionalized black talc powder, and additives (2.5 g of zinc stearate, 2.5 g of dicumyl peroxide, 1 g of antioxidant 1010), mix them evenly in a high-speed mixer, melt-extrude them in a twin-screw extruder (the temperature is 120 - 170 °C), cool, pelletize, and dry to obtain the functionalized black talc-filled EVA composite material. Then use a flat vulcanizing machine to make the functionalized black talc-filled EVA composite material into a standard specimen for performance testing. The experimental results show that the tensile strength is 10.30 MPa and the elongation at break is 789%.

[0035] Example 2:

[0036] The difference between this example and Example 1 is that when preparing the composite material (functionalized black talc-filled EVA composite material) in this example, according to the following masses: 500 g of EVA, 25 g of the functionalized black talc powder, and additives (2.5 g of zinc stearate, 2.5 g of dicumyl peroxide, 1 g of antioxidant 1010), mix them evenly in a high-speed mixer, melt-extrude them in a twin-screw extruder (the temperature is 120 - 170 °C), cool, pelletize, and dry to obtain the functionalized black talc-filled EVA composite material. The experimental results show that the tensile strength is 10.70 MPa and the elongation at break is 748%.

[0037] Example 3:

[0038] The difference between this example and Example 1 is that when preparing the composite material in this example, the following masses are used: 500 g of EVA, 50 g of functionalized black talc powder, and additives (2.5 g of zinc stearate, 2.5 g of dicumyl peroxide, 1 g of antioxidant 1010). They are mixed evenly in a high-speed mixer, melt-extruded in a twin-screw extruder (temperature: 120 - 170 °C), cooled, pelletized, and dried to obtain the functionalized black talc-filled EVA composite material. Other steps are exactly the same as those in Example 1. The experimental results show that the tensile strength is 11.87 MPa and the elongation at break is 813%.

[0039] Example 4:

[0040] The difference between this example and Example 1 is that when preparing the composite material in this example, the following masses are used: 500 g of EVA, 75 g of functionalized black talc powder, and additives (2.5 g of zinc stearate, 2.5 g of dicumyl peroxide, 1 g of antioxidant 1010). They are mixed evenly in a high-speed mixer, melt-extruded in a twin-screw extruder (temperature: 120 - 170 °C), cooled, pelletized, and dried to obtain the functionalized black talc-filled EVA composite material. The experimental results show that the tensile strength is 11.07 MPa and the elongation at break is 721%.

[0041] Example 5:

[0042] The difference between this example and Example 1 is that when preparing the composite material in this example, the following masses are used: 500 g of EVA, 100 g of functionalized black talc powder, and additives (2.5 g of zinc stearate, 2.5 g of dicumyl peroxide, 1 g of antioxidant 1010). They are mixed evenly in a high-speed mixer, melt-extruded in a twin-screw extruder (temperature: 120 - 170 °C), cooled, pelletized, and dried to obtain the functionalized black talc-filled EVA composite material. The experimental results show that the tensile strength is 9.34 MPa and the elongation at break is 562%.

[0043] Example 6:

[0044] The difference between this example and Example 1 is that when preparing the composite material in this example, the following masses are used: 500 g of EVA, 150 g of functionalized black talc powder, and additives (2.5 g of zinc stearate, 2.5 g of dicumyl peroxide, 1 g of antioxidant 1010). They are mixed evenly in a high-speed mixer, melt-extruded in a twin-screw extruder (temperature: 120 - 170 °C), cooled, pelletized, and dried to obtain the functionalized black talc-filled EVA composite material. The experimental results show that the tensile strength is 8.03 MPa and the elongation at break is 480%.

[0045] Comparing the data of Comparative Examples 1 to 6, it is found that the performance is optimal when 10 parts of functionalized black talc powder is filled. In subsequent Examples and Comparative Examples, 10 parts of powder is filled for the preparation and testing of the composite material.

[0046] Example 7:

[0047] Take black talc ore for preliminary crushing. Place the black talc in an ethanol aqueous solution with a volume concentration of 50%. Take the black talc and wet ball mill it in a 100 ml solution of ethanol and water with a volume ratio of 1:1 at 1000 r / min for 10 h. After taking out the obtained product, wash it repeatedly by centrifugation and deionized water, dry it, and grind it through a 200-mesh sieve to obtain the required 200-mesh black talc powder. Put 30 g of black talc powder into 300 ml of 4 mol / L hydrochloric acid solution for pretreatment. The condition is to stir at 80 °C for 6 h. The obtained mixed solution (the first mixed solution) is filtered, washed with deionized water until neutral, dried (dried at 70 °C for 24 h), ground, and passed through a 200-mesh sieve to obtain 28.6 g of pretreated black talc powder; then immerse 25 g of the pretreated black talc powder in 250 ml of 40% ethanol aqueous solution to obtain a second mixed solution. Use hydrochloric acid to adjust the pH to 5, stir and ultrasonically homogenize it at room temperature to obtain a suspension. Add tetraethyl orthosilicate and vinyltrimethoxysilane in sequence. The dosages of the pretreated black talc powder, tetraethyl orthosilicate, and vinyltrimethoxysilane are 25 g, 25 ml, and 25 ml respectively. Stir at 60 °C for 6 h. The obtained mixed solution is filtered, washed three times with absolute ethanol, dried at 60 °C for 24 h, ground, and passed through a 200-mesh sieve to obtain 26.3 g of the functionalized black talc powder;

[0048] According to the following masses: 500 g of EVA, 50 g of functionalized black talc powder, and additives (2.5 g of zinc stearate, 2.5 g of dicumyl peroxide, 1 g of antioxidant 1010), mix them evenly in a high-speed mixer, melt extrude them in a twin-screw extruder (the temperature is 120 - 170 °C), cool, pelletize, and dry to obtain the functionalized black talc-filled EVA composite material. Then use a flat vulcanizing machine to make the functionalized black talc-filled EVA composite material into a standard specimen for performance testing. The experimental results show that the tensile strength is 11.44 MPa and the elongation at break is 788%.

[0049] Example 8:

[0050] Take the black talc ore for preliminary crushing. Place the black talc in an ethanol aqueous solution with a volume concentration of 50%, and wet ball mill it at 1000 r / min for 10 h. After taking out the obtained product, wash it repeatedly by centrifugation and deionized water, dry it, grind it through a 200-mesh sieve to obtain the required 200-mesh black talc powder. Put 30 g of the black talc powder into 300 ml of 4 mol / L hydrochloric acid solution for pretreatment under the condition of stirring at 80 °C for 6 h. Filter the obtained mixed solution (the first mixed solution), wash it with deionized water until neutral, dry it (dry at 70 °C for 24 h), grind it, and pass it through a 200-mesh sieve to obtain 28.5 g of pretreated black talc powder; then immerse 25 g of the pretreated black talc powder in 250 ml of 40% ethanol aqueous solution to obtain a second mixed solution, adjust the pH to 5 with hydrochloric acid, stir and ultrasonically homogenize it at room temperature to obtain a suspension, and sequentially add tetraethyl orthosilicate and vinyltrimethoxysilane. The amounts of the pretreated black talc powder, tetraethyl orthosilicate, and vinyltrimethoxysilane are 25 g, 12.5 ml, and 12.5 ml respectively. Stir at 60 °C for 6 h. Filter the obtained mixed solution, wash it three times with absolute ethanol, dry it at 60 °C for 24 h, grind it, and pass it through a 200-mesh sieve to obtain 26.0 g of the functionalized black talc powder;

[0051] According to the following masses: 500 g of EVA, 50 g of the functionalized black talc powder, and additives (2.5 g of zinc stearate, 2.5 g of dicumyl peroxide, 1 g of antioxidant 1010), mix them evenly in a high-speed mixer, melt and extrude them in a twin-screw extruder (the temperature is 120 - 170 °C), cool, pelletize, and dry to obtain the functionalized black talc-filled EVA composite material. Then use a flat vulcanizer to make the functionalized black talc-filled EVA composite material into standard specimens for performance testing. The experimental results show that the tensile strength is 11.28 MPa and the elongation at break is 752%.

[0052] Example 9:

[0053] Take the black talc ore for preliminary crushing. Place the black talc in an ethanol aqueous solution with a volume concentration of 50%, and wet ball mill it at 1000 r / min for 10 h. After taking out the obtained product, wash it repeatedly by centrifugation and deionized water, dry it, grind it through a 200-mesh sieve to obtain the required 200-mesh black talc powder. Put 30 g of the black talc powder into 300 ml of 4 mol / L hydrochloric acid solution for pretreatment under the condition of stirring at 80 °C for 6 h. Filter the obtained mixed solution (the first mixed solution), wash it with deionized water until neutral, dry it (dry at 70 °C for 24 h), grind it, and pass it through a 200-mesh sieve to obtain 28.6 g of pretreated black talc powder; then immerse 25 g of the pretreated black talc powder in 250 ml of 40% ethanol aqueous solution to obtain a second mixed solution, adjust the pH to 5 with hydrochloric acid, stir and ultrasonically homogenize it at room temperature to obtain a suspension, and sequentially add tetraethyl orthosilicate and vinyltrimethoxysilane. The dosages of the pretreated black talc powder, tetraethyl orthosilicate, and vinyltrimethoxysilane are 25 g, 12.5 ml, and 25 ml respectively. Stir at 60 °C for 6 h. Filter the obtained mixed solution, wash it three times with absolute ethanol, dry it at 60 °C for 24 h, grind it, and pass it through a 200-mesh sieve to obtain 26.6 g of the functionalized black talc powder;

[0054] According to the following masses: 500 g of EVA, 50 g of the functionalized black talc powder, and additives (2.5 g of zinc stearate, 2.5 g of dicumyl peroxide, 1 g of antioxidant 1010), mix them evenly in a high-speed mixer, melt extrude them in a twin-screw extruder (temperature is 120 - 170 °C), cool, pelletize, and dry to obtain the functionalized black talc-filled EVA composite material. Then use a flat vulcanizing machine to make the functionalized black talc-filled EVA composite material into a standard specimen for performance testing. The experimental results show that the tensile strength is 11.54 MPa and the elongation at break is 775%.

[0055] Example 10:

[0056] The difference between this example and Example 1 is that when preparing the composite material in this example, according to the following masses: 500 g of EVA, 50 g of the functionalized black talc powder, and additives (1 g of zinc stearate, 1 g of dicumyl peroxide, 0.5 g of antioxidant 1010), mix them evenly in a high-speed mixer, melt extrude them in a twin-screw extruder (temperature is 120 - 170 °C), cool, pelletize, and dry to obtain the functionalized black talc-filled EVA composite material. The experimental results show that the tensile strength is 11.03 MPa and the elongation at break is 740%.

[0057] Example 11:

[0058] The difference between this example and Example 1 is that when preparing the composite material in this example, the following masses are used: 500 g of EVA, 50 g of functionalized black talc powder, and additives (5 g of zinc stearate, 2.5 g of dicumyl peroxide, 1.5 g of antioxidant 1010). They are mixed evenly in a high-speed mixer, melt-extruded (at a temperature of 120 - 170 °C), cooled, pelletized, and dried in a twin-screw extruder to obtain the functionalized black talc-filled EVA composite material. The experimental results show that the tensile strength is 11.42 MPa and the elongation at break is 767%.

[0059] Comparative Example 1:

[0060] The black talc ore is taken for preliminary crushing. The black talc is placed in an ethanol aqueous solution with a volume concentration of 50%, and wet ball-milled at 1000 r / min for 10 h. After taking out the obtained product, it is washed repeatedly by centrifugation and deionized water, dried, and ground through a 200-mesh sieve to obtain the required 200-mesh black talc powder. 30 g of the black talc powder is put into 300 ml of 4 mol / L hydrochloric acid solution for pretreatment under the condition of stirring at 80 °C for 6 h. The obtained mixed solution (the first mixed solution) is filtered, washed with deionized water until neutral, dried (dried at 70 °C for 24 h), ground, and passed through a 200-mesh sieve to obtain 28.5 g of pretreated black talc powder; then 25 g of the pretreated black talc powder is immersed in 250 ml of 40% ethanol aqueous solution to obtain a second mixed solution, which is adjusted to pH = 5 with hydrochloric acid, stirred and ultrasonically homogenized at room temperature to obtain a suspension. Tetraethyl orthosilicate and vinyltrimethoxysilane are added in sequence. The amounts of pretreated black talc, tetraethyl orthosilicate, and vinyltrimethoxysilane used are 25 g, 25 ml, and 12.5 ml respectively. It is stirred at 60 °C for 6 h. The obtained mixed solution is filtered, washed three times with absolute ethanol, dried at 60 °C for 24 h, ground, and passed through a 200-mesh sieve to obtain 26.5 g of the functionalized black talc powder; according to the following masses: 500 g of EVA, 50 g of functionalized black talc powder, and additives (2.5 g of zinc stearate, 1 g of antioxidant 1010) (the additives do not contain graft initiator), they are mixed evenly in a high-speed mixer, melt-extruded (at a temperature of 120 - 170 °C), cooled, pelletized, and dried in a twin-screw extruder to obtain the functionalized black talc-filled EVA composite material. Then, a flat vulcanizer is used to make standard specimens for performance testing. The experimental results are that the tensile strength is 9.32 MPa and the elongation at break is 743%. The results show that without the action of the graft initiator, the performance of the composite material is affected, and the overall performance is reduced compared with Example 3, indicating that the use of the graft initiator can improve the performance of the composite material.

[0061] Comparative Example 2: ·

[0062] Take the black talc ore for preliminary crushing. Place the black talc in an ethanol aqueous solution with a volume concentration of 50%, and wet ball mill it at 1000 r / min for 10 h. After taking out the obtained product, wash it repeatedly by centrifugation and deionized water, dry it, grind it through a 200-mesh sieve to obtain the required 200-mesh black talc powder. According to the following masses: 500 g of EVA, 50 g of black talc powder, and additives (2.5 g of zinc stearate, 2.5 g of dicumyl peroxide, 1 g of antioxidant 1010), mix them evenly in a high-speed mixer, and melt extrude (at a temperature of 120 - 170 °C), cool, pelletize, and dry in a twin-screw extruder to obtain the EVA composite material. Then use a flat vulcanizer to make standard specimens for performance testing. The experimental results show that the tensile strength is 7.97 MPa and the elongation at break is 680%. The results show that when the provided preparation method is not used, the performance of the composite material is affected and the overall performance is poor, proving that the provided method for preparing the composite material is beneficial to improving the performance of the composite material.

[0063] Table 1: Comparison table of the formula and mechanical properties of the composite materials prepared in each example and comparative example

[0064]

[0065]

[0066] Table 2 shows that the volume of the functionalized black talc used as a modifier is calculated based on the mass of the pretreated black talc powder contained in the suspension

[0067]

Claims

1. A method for preparing a functionalized black talc-filled EVA composite material, characterized in that: EVA, functionalized black talc powder and auxiliary agent in a mass ratio of 100:1-30:0.5-1.8 are uniformly mixed in a high-speed mixer, and the functionalized black talc-filled EVA composite material is prepared by melt extrusion at a temperature of 120-170°C in a twin-screw extruder, cooling, pelletizing and drying; the auxiliary agent is a mixture of zinc stearate, grafting initiator and antioxidant 1010 in a mass ratio of 0.2-1:0.2-0.5:0.1-0.3; the functionalized black talc powder is prepared as follows: (1) immersing black talc powder in a 2-8 M hydrochloric acid solution, stirring at 55-85° C. for 6-8 hours to obtain a first mixed solution, filtering to remove the filtrate, washing with deionized water until the pH is neutral, drying, grinding, and passing through a 200-mesh sieve to obtain a pretreated black talc powder; (2) immersing the pretreated black talc powder in step (1) in an ethanol aqueous solution having a mass concentration of 40% to 60% to obtain a second mixed solution, adjusting the pH to 4 to 6 and stirring evenly to obtain a suspension; (3) Adding tetraethyl orthosilicate and organosilane to the suspension in step (2) in sequence, stirring at 45-70° C. for 6-8 hours, filtering to remove the filtrate, washing with anhydrous ethanol, drying, grinding, and sieving to obtain functionalized black talc powder; the volume of the tetraethyl orthosilicate is 0.5-1 ml / g based on the mass of the pretreated black talc powder contained in the suspension; the volume of the organosilane is 0.5-1 ml / g based on the mass of the pretreated black talc powder contained in the suspension.

2. The method for preparing the functionalized black talc-filled EVA composite material according to claim 1, characterized in that: The volume of the hydrochloric acid solution in step (1) is 5 ml / g-20 ml / g based on the mass of the black talc powder.

3. The method for preparing the functionalized black talc-filled EVA composite material according to claim 1, characterized in that: The volume of the ethanol aqueous solution in step (2) is 10 ml / g-20 ml / g based on the mass of the pretreated black talc powder.

4. The method for preparing the functionalized black talc-filled EVA composite material according to claim 1, characterized in that: The organosilane in step (3) is one or more of vinyltrimethoxysilane, vinyltriethoxysilane, isopropyltri(dioctylpyrophosphate)titanate or γ-methacryloxypropyltrimethoxysilane.

5. The method for preparing the functionalized black talc-filled EVA composite material according to claim 1, characterized in that In step (3), the volume of ethyl orthosilicate contained in the suspension is 1 ml / g based on the mass of the pretreated black talc powder contained in the suspension; the volume of organosilane is 0.5 ml / g based on the mass of the pretreated black talc powder contained in the suspension.

6. The method for preparing the functionalized black talc-filled EVA composite material according to claim 1, characterized in that: The grafting initiator is one or more of cumene hydroperoxide, dicumyl peroxide or 2,5-dimethyl-2,5-di-tert-butyl peroxide hexane.

7. The method for preparing the functionalized black talc-filled EVA composite material according to claim 1, characterized in that: The mass ratio of the EVA, the functionalized black talc powder and the auxiliary agent is 100:10:1.

2.

8. The method for preparing the functionalized black talc-filled EVA composite material according to claim 1, characterized in that: The grafting initiator is dicumyl peroxide, and the mass ratio of zinc stearate, grafting initiator and antioxidant 1010 is 0.5:0.5:0.

2.

9. The method for preparing the functionalized black talc-filled EVA composite material according to claim 1, characterized in that The black talc powder is prepared as follows: The black talc ore is initially crushed, and the black talc is placed in an ethanol aqueous solution with a volume concentration of 50%, and wet ball milled at 600-1000r / min for 8-10h. The obtained product is centrifuged, washed with deionized water, dried, ground, and passed through a 200-mesh sieve to obtain the black talc powder.

10. A product prepared by the method for preparing the functionalized black talc-filled EVA composite material as claimed in claim 1.

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