Anti-aging polyethylene rotational molding modified material and preparation method thereof

Abstract

The invention discloses an anti-aging polyethylene rotational molding modified material and a preparation method thereof, and the modified material comprises the following raw materials: linear low density polyethylene, metallocene polyethylene rotational molding material, a modified additive, dicumyl peroxide, a modified filler and a Karst catalyst, in the melt extrusion process of the raw materials, part of double bonds on the modified additive can be grafted with polyethylene molecular chains, and the remaining double bonds are grafted with Si-H on the modified filler under the action of a Karst catalyst, so that the modified filler is uniformly dispersed in the material to form a protective layer; the surface of the modified filler contains a hydroxyl benzophenone structure, so that ultraviolet rays can be converted into harmless heat energy to be released, and an internal zirconium organic framework can absorb and scatter high-energy ultraviolet rays; the opportunity that ultraviolet rays directly act on polyethylene molecular chains is reduced, and the anti-aging effect of the material is further improved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of rotational molding modified material, and particularly relates to a kind of anti-aging polyethylene rotational molding modified material and a preparation method thereof. BACKGROUND

[0002] Rotational molding is also known as spin molding, rotational molding, rotational molding, rotational casting and rotation molding. Its working principle is: quantitative powder resin is loaded into a cold mold, the mold is closed, heated at the same time, and the mold is driven by a rotational molding machine to slowly revolve around two perpendicular axes to make the resin in the cavity melt and uniformly coat the inner surface of the entire mold by gravity and centrifugal force. Finally, a hollow product is obtained by cooling and demolding. Rotational molding has many characteristics: the price of rotational molding equipment and mold is low, and the service life is long; complex parts do not need to be assembled after molding; various products and colors can be molded at the same time; and less waste is generated. Rotational molding products are used in many fields, including children's outdoor toys, road facilities, boats, etc. In the logistics field, preservation boxes, corrosion-resistant boxes, etc. In the environmental protection field, garbage burial barrels, septic tanks, etc. In the industrial field, vehicle trim parts, oil tanks, water tanks, etc. However, the existing polyethylene rotational molding material will age significantly under high temperature environment or long time illumination, which will reduce its performance and affect its use. SUMMARY

[0003] The application aims to provide an anti-aging polyethylene rotational molding modified material and a preparation method thereof, which solves the problem of poor anti-aging effect of the rotational molding modified material at present.

[0004] The application can be achieved by the following technical solutions. A preparation method of an anti-aging polyethylene rotational molding modified material, specifically comprising the following steps: Step A1: uniformly mix lithium dimethylsilanolate and tetrahydrofuran, protect with nitrogen, stir at a speed of 120-150 r / min and a temperature of 0 DEG C, add trifluoropropylmethyltrisiloxane, heat to 20-25 DEG C, react for 6-8 h, add gamma-chloropropyltrichlorosilane, and react for 1-1.5 h to obtain an additive; Step A2: mix the additive, 2,6-di-tert-butyl-4-vinylphenol, chloroplatinic acid and DMF, protect with nitrogen, react for 6-8 h at a speed of 200-300 r / min and a temperature of 80-85 DEG C to obtain a pretreated additive, mix 4-maleimide phenol, potassium carbonate and DMF, protect with nitrogen, stir at a speed of 150-200 r / min and a temperature of 40-50 DEG C, add the pretreated additive, heat to 70-80 DEG C, and react for 4-6 h to obtain a modified additive.

[0005] Step A3: linear low density polyethylene, metallocene polyethylene rotomolding material, modified additive, dicumyl peroxide, modified filler and kast catalyst were added into double screw extruder, extruded and cooled under the conditions of zone 1 temperature 80℃, zone 2 temperature 130℃, zone 3 temperature 180℃, zone 4 temperature 230℃, zone 5 temperature 230℃ and head temperature 230℃, to obtain the aging-resistant polyethylene rotomolding modified material.

[0006] Further, the molar ratio of the Si-Cl bond on the lithium dimethylsilanolate, trifluoropropylmethylcyclotrisiloxane and gamma-chloropropyltrichlorosilane in step A1 is 1:3:1.

[0007] Further, the molar ratio of the Si-H bond on the additive and 2,6-di-tert-butyl-4-vinylphenol in step A2 is 1:1, the amount of chloroplatinic acid is 0.01% of the mass of 2,6-di-tert-butyl-4-vinylphenol, and the molar ratio of 4-maleimide phenol, potassium carbonate and pretreated additive is 1:1.1:1.

[0008] Further, the weight ratio of the linear low density polyethylene, metallocene polyethylene rotomolding material, modified additive, dicumyl peroxide, modified filler and kast catalyst in step A3 is 30-40:80-100:8-10:0.05-0.1:10-15:1-3.

[0009] Further, the modified filler is prepared by the following steps: Step B1: 2,4-dihydroxybenzophenone and ethanol were mixed, stirred at a speed of 150-200 r / min and at a temperature of 0℃, and sodium hydroxide solution and dimethyl sulfate were added, then the temperature was raised to 20-25℃ and the reaction was carried out for 6-8 h to obtain intermediate 1, phosphorus oxychloride was added to the reaction kettle, stirred at a speed of 60-80 r / min and at a temperature of 0℃, DMF was added, the temperature was raised to 20-25℃, and the reaction was carried out for 30-40 min, then intermediate 1 was added, the temperature was raised to 75-80℃, and the reaction was carried out for 3-5 h to obtain intermediate 2; Step B2: intermediate 2 and dichloromethane were uniformly mixed, stirred at a speed of 150-200 r / min and at a temperature of 20-25℃, and aluminum chloride was added, and the reaction was carried out for 4-6 h, then the temperature was lowered to 0℃, the pH value was adjusted to 4-5, and intermediate 3 was obtained, zirconium tetrachloride was dissolved in DMF, stirred at a speed of 800-1000 r / min and at a temperature of 20-25℃, 2-amino terephthalic acid and concentrated hydrochloric acid were added, stirred for 50-60 min, stirring was stopped and the temperature was raised to 110-120℃, and the reaction was carried out for 20-25 h to obtain a zirconium organic framework. Step B3: the zirconium organic framework is dispersed in ethanol, nitrogen is introduced for protection, stirring is carried out at a rotation speed of 200-300 r / min and a temperature of 60-65 DEG C, intermediate 3 and anhydrous magnesium sulfate are added, the temperature is raised to 80-82 DEG C, and reflux treatment is carried out for 3-5 h, the functionalized filler is prepared, the functionalized filler, triethylamine and tetrahydrofuran are uniformly mixed, nitrogen is introduced for protection, stirring is carried out at a rotation speed of 200-300 r / min and a temperature of 0-3 DEG C, dimethylchlorosilane is added, the temperature is raised to 25-30 DEG C, and reaction is carried out for 6-8 h, and the modified filler is prepared.

[0010] Further, the use amount ratio of 2,4-dihydroxybenzophenone, sodium hydroxide solution and dimethyl sulfate in step B1 is 4 mmol:5 mL:12 mmol, the concentration of sodium hydroxide solution is 2 mol / L, and the molar ratio of phosphorus oxychloride, DMF and intermediate 1 is 5:8:4.

[0011] Further, the molar ratio of intermediate 2 and aluminum chloride in step B2 is 1:3, and the use amount ratio of zirconium tetrachloride, 2-amino terephthalic acid and concentrated hydrochloric acid is 1 mmol:1 mmol:2 mL, and the mass fraction of concentrated hydrochloric acid is 36%.

[0012] Further, the molar ratio of amino groups on the zirconium organic framework, intermediate 3 and anhydrous magnesium sulfate in step B3 is 1:1:1, and the molar ratio of phenolic hydroxyl groups on the functionalized filler, triethylamine and dimethylchlorosilane is 2:1.1:1.

[0013] The application discloses a kind of anti-aging polyethylene rotational molding modified material, which comprises the following raw materials: linear low density polyethylene, metallocene polyethylene rotational molding material, modified additive, dicumyl peroxide, modified filler and kast catalyst, the modified additive is prepared by using dimethylsilanol lithium as initiator, trifluoropropylmethylcyclotrisiloxane as polymerization monomer, and then adding γ-chloropropyltrichlorosilane, so that Si-Cl bond on γ-chloropropyltrichlorosilane reacts with silanol lithium to obtain the additive, the additive is reacted with 2,6-di-tert-butyl-4-vinylphenol to make Si-H bond on the additive react with double bond on 2,6-di-tert-butyl-4-vinylphenol to obtain pretreated additive, and the pretreated additive is reacted with 4-maleimide phenol to make phenolic hydroxyl group on 4-maleimide phenol react with C-Cl bond on the pretreated additive to obtain modified additive.

[0014] The modified filler is prepared by the following steps: taking 2,4-dihydroxybenzophenone as raw material, treating with dimethyl sulfate to etherize the hydroxyl group on the 2,4-dihydroxybenzophenone to obtain intermediate 1, treating intermediate 1 with phosphorus oxychloride and DMF to perform Vilsmeier-Haack reaction on intermediate 1 to obtain intermediate 2, treating intermediate 2 with aluminum trichloride to perform demethylation treatment to obtain intermediate 3, reacting zirconium tetrachloride and 2-amino terephthalic acid to form a zirconium organic framework, and reacting the zirconium organic framework and intermediate 3 to make the amino group on the zirconium organic framework react with the aldehyde group on intermediate 3 to form an imine, thereby obtaining a functionalized filler, and reacting the functionalized filler and dimethylchlorosilane to make the hydroxyl group on the benzene ring of the surface of the functionalized filler react with the Si-Cl bond on dimethylchlorosilane, thereby obtaining the modified filler.

[0015] During the raw material melt extrusion process, part of the double bonds on the modified additive can be grafted with polyethylene molecules, and the remaining double bonds are grafted with Si-H on the modified filler under the action of Karstedt catalyst, thereby making the modified filler uniformly dispersed in the material, and further forming a protective layer to prevent the penetration and diffusion of aging factors such as oxygen and ultraviolet light, and the surface of the modified filler contains a hydroxybenzophenone structure, which can convert ultraviolet light into harmless heat energy, the internal zirconium organic framework can absorb and scatter high-energy ultraviolet light, reducing the opportunity for ultraviolet light to directly act on the polyethylene molecular chain, and the nanopore can limit the activity of the polyethylene molecular chain, thereby inhibiting chain transfer processes such as β-H elimination reaction that leads to molecular chain rupture, and the fluorine-containing organosilicon segment in the modified filler can form a protective layer on the surface, reducing the direct attack of ultraviolet light on the main chain of the modified resin, and cooperating with the hindered phenol structure in the molecule, further improving the aging resistance of the material. DETAILED DESCRIPTION

[0016] The technical solutions in the embodiments of the present application will be described below in a clear and complete manner. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0017] Embodiment 1: a preparation method of an aging-resistant polyethylene rotational molding modified material, specifically comprising the following steps: Step A1: uniformly mix dimethylsilanol lithium and tetrahydrofuran, protect with nitrogen, stir at a rotation speed of 120 r / min and a temperature of 0℃, add trifluoropropylmethylcyclotrisiloxane, heat to 20℃, and react for 6h, then add γ-chloropropyltrichlorosilane and react for 1h to obtain an additive. Step A2: The additive, 2,6-di-tert-butyl-4-vinylphenol, chloroplatinic acid and DMF were mixed, protected by nitrogen, and reacted at 200 r / min and 80℃ for 6h to obtain a pretreated additive. 4-Maleimide phenol, potassium carbonate and DMF were mixed, protected by nitrogen, and stirred at 150 r / min and 40℃, and then the pretreated additive was added. The temperature was raised to 70℃, and reacted for 4h to obtain a modified additive.

[0018] Step A3: Linear low density polyethylene, metallocene polyethylene rotomolding material, modified additive, dicumyl peroxide, modified filler and cast catalyst were added into a twin-screw extruder, and extruded and cooled under the conditions of zone 1 temperature 80℃, zone 2 temperature 130℃, zone 3 temperature 180℃, zone 4 temperature 230℃, zone 5 temperature 230℃ and die temperature 230℃ to obtain an aging-resistant polyethylene rotomolding modified material.

[0019] The molar ratio of lithium dimethylsilanolate, trifluoropropylmethylcyclotrisiloxane and Si-Cl bond on γ-chloropropyltrichlorosilane in step A1 was 1:3:1.

[0020] The molar ratio of Si-H bond on the additive and 2,6-di-tert-butyl-4-vinylphenol in step A2 was 1:1, and the amount of chloroplatinic acid was 0.01% of the mass of 2,6-di-tert-butyl-4-vinylphenol. The molar ratio of 4-maleimide phenol, potassium carbonate and pretreated additive was 1:1.1:1.

[0021] The weight ratio of linear low density polyethylene, metallocene polyethylene rotomolding material, modified additive, dicumyl peroxide, modified filler and cast catalyst in step A3 was 30:80:8:0.05:10:1. The density of linear low density polyethylene was 0.939 g·cm -3 , and the melt index was 5.8 g·(10 min) -1 . The density of metallocene polyethylene rotomolding material was 0.933 g·cm -3 , and the melt index was 5.8 g·(10 min) -1 .

[0022] The modified filler was prepared by the following steps: Step B1: 2,4-dihydroxybenzophenone and ethanol were mixed, stirred at a rotation speed of 150 r / min and a temperature of 0 DEG C, and sodium hydroxide solution and dimethyl sulfate were added, the temperature was raised to 20 DEG C, and the reaction was carried out for 6 h to prepare intermediate 1; phosphorus oxychloride was added to a reaction kettle, stirred at a rotation speed of 60 r / min and a temperature of 0 DEG C, and DMF was added, the temperature was raised to 20 DEG C, and the reaction was carried out for 30 min, then intermediate 1 was added, the temperature was raised to 75 DEG C, and the reaction was carried out for 3 h to prepare intermediate 2; Step B2: intermediate 2 and dichloromethane were uniformly mixed, stirred at a rotation speed of 150 r / min and a temperature of 20 DEG C, and aluminum chloride was added, the reaction was carried out for 4 h, the temperature was lowered to 0 DEG C, and the pH value was adjusted to 4 to prepare intermediate 3; zirconium tetrachloride was dissolved in DMF, stirred at a rotation speed of 800 r / min and a temperature of 20 DEG C, and 2-amino terephthalic acid and concentrated hydrochloric acid were added, the stirring was carried out for 50 min, the stirring was stopped, and the temperature was raised to 110 DEG C, and the reaction was carried out for 20 h to prepare a zirconium organic framework; Step B3: the zirconium organic framework was dispersed in ethanol, protected by nitrogen, stirred at a rotation speed of 200 r / min and a temperature of 60 DEG C, and intermediate 3 and anhydrous magnesium sulfate were added, the temperature was raised to 80 DEG C, and the reflux treatment was carried out for 3 h to prepare a functionalized filler; the functionalized filler, triethylamine and tetrahydrofuran were uniformly mixed, protected by nitrogen, stirred at a rotation speed of 200 r / min and a temperature of 0 DEG C, and dimethylchlorosilane was added, the temperature was raised to 25 DEG C, and the reaction was carried out for 6 h to prepare a modified filler.

[0023] The amount ratio of 2,4-dihydroxybenzophenone, sodium hydroxide solution and dimethyl sulfate in step B1 was 4 mmol:5 mL:12 mmol, the concentration of sodium hydroxide solution was 2 mol / L, and the molar ratio of phosphorus oxychloride, DMF and intermediate 1 was 5:8:4.

[0024] The molar ratio of intermediate 2 and aluminum chloride in step B2 was 1:3, and the amount ratio of zirconium tetrachloride, 2-amino terephthalic acid and concentrated hydrochloric acid was 1 mmol:1 mmol:2 mL, and the mass fraction of concentrated hydrochloric acid was 36%.

[0025] The molar ratio of amino groups on the zirconium organic framework, intermediate 3 and anhydrous magnesium sulfate in step B3 was 1:1:1, and the molar ratio of phenolic hydroxyl groups on the functionalized filler, triethylamine and dimethylchlorosilane was 2:1.1:1.

[0026] Example 2, a preparation method of an anti-aging polyethylene rotational molding modified material, specifically comprising the following steps: Step A1: Mix lithium dimethylsilyl alcohol and tetrahydrofuran evenly, purge with nitrogen, stir and add trifluoropropylmethylcyclotrisiloxane at 120 r / min and 0℃, heat to 25℃ and react for 7 h, then add γ-chloropropyltrichlorosilane and react for 1.3 h to obtain the additive. Step A2: Mix the additive, 2,6-di-tert-butyl-4-vinylphenol, chloroplatinic acid and DMF, purge with nitrogen, and react for 7 hours at 200 r / min and 85°C to obtain the pretreated additive. Mix 4-maleimide-based phenol, potassium carbonate and DMF, purge with nitrogen, and stir at 150 r / min and 45°C while adding the pretreated additive. Heat to 75°C and react for 5 hours to obtain the modified additive.

[0027] Step A3: Linear low-density polyethylene, metallocene polyethylene rotomolded plastic, modified additives, dicumyl peroxide, modified filler and cassiterite catalyst are added to a twin-screw extruder and extruded and cooled under the following conditions: zone 1 temperature 80℃, zone 2 temperature 130℃, zone 3 temperature 180℃, zone 4 temperature 230℃, zone 5 temperature 230℃, and die head temperature 230℃, to obtain aging-resistant polyethylene rotomolded modified material.

[0028] The molar ratio of Si-Cl bonds on lithium dimethylsilanolate, trifluoropropylmethylcyclotrisiloxane and γ-chloropropyltrichlorosilane in step A1 is 1:3:1.

[0029] The molar ratio of Si-H bonds on the additive described in step A2 to 2,6-di-tert-butyl-4-vinylphenol is 1:1, the amount of chloroplatinic acid is 0.01% of the mass of 2,6-di-tert-butyl-4-vinylphenol, and the molar ratio of 4-maleimide-phenol, potassium carbonate and pretreatment additive is 1:1.1:1.

[0030] The weight ratio of linear low-density polyethylene, metallocene polyethylene molten plastic, modified additives, dicumyl peroxide, modified filler, and cassiterite catalyst mentioned in step A3 is 35:90:9:0.08:13:2, and the density of the linear low-density polyethylene is 0.939 g·cm³. -3 Melt index 5.8 g·(10 min) -1 The density of metallocene polyethylene rotomolded plastic is 0.933 g·cm³. -3 Melt index 5.8 g·(10 min) -1 .

[0031] The modified filler is prepared by the following steps: Step B1: Mix 2,4-dihydroxybenzophenone and ethanol, stir at 200 r / min and 0°C, add sodium hydroxide solution and dimethyl sulfate, heat to 20°C and react for 7 h to obtain intermediate 1. Add phosphorus oxychloride to the reaction vessel, stir at 80 r / min and 0°C, add DMF, heat to 23°C and react for 35 min, add intermediate 1, heat to 78°C and react for 4 h to obtain intermediate 2. Step B2: Mix intermediate 2 and dichloromethane evenly, stir and add aluminum trichloride at 200 r / min and 20°C, react for 5 h, cool to 0°C, adjust pH to 5 to obtain intermediate 3. Dissolve zirconium tetrachloride in DMF, stir and add 2-aminoterephthalic acid and concentrated hydrochloric acid at 800 r / min and 25°C, stir for 55 min, stop stirring and heat to 115°C, react for 25 h to obtain zirconium organic framework; Step B3: Disperse the zirconium organic framework in ethanol, purge with nitrogen, stir at 200 r / min and 65 °C, add intermediate 3 and anhydrous magnesium sulfate, heat to 80 °C, reflux for 4 h to obtain the functionalized filler. Mix the functionalized filler, triethylamine and tetrahydrofuran evenly, purge with nitrogen, stir at 200 r / min and 3 °C, add dimethylchlorosilane, heat to 30 °C, react for 7 h to obtain the modified filler.

[0032] The ratio of 2,4-dihydroxybenzophenone, sodium hydroxide solution, and dimethyl sulfate used in step B1 is 4 mmol:5 mL:12 mmol, the concentration of sodium hydroxide solution is 2 mol / L, and the molar ratio of phosphorus oxychloride, DMF, and intermediate 1 is 5:8:4.

[0033] The molar ratio of intermediate 2 and aluminum trichloride in step B2 is 1:3, the ratio of zirconium tetrachloride, 2-aminoterephthalic acid and concentrated hydrochloric acid is 1 mmol:1 mmol:2 mL, and the mass fraction of concentrated hydrochloric acid is 36%.

[0034] In step B3, the molar ratio of amino groups, intermediate 3, and anhydrous magnesium sulfate on the zirconium organic framework is 1:1:1, and the molar ratio of phenolic hydroxyl groups, triethylamine, and dimethylchlorosilane on the functionalized filler is 2:1.1:1.

[0035] Example 3, a method for preparing an aging-resistant polyethylene rotational molding modified material, specifically includes the following steps: Step A1: Mix lithium dimethylsilyl alcohol and tetrahydrofuran evenly, purge with nitrogen, stir and add trifluoropropylmethylcyclotrisiloxane at 150 r / min and 0℃, heat to 25℃ and react for 8 h, then add γ-chloropropyltrichlorosilane and react for 1.5 h to obtain the additive. Step A2: Mix the additive, 2,6-di-tert-butyl-4-vinylphenol, chloroplatinic acid and DMF, purge with nitrogen, and react for 8 hours at 300 r / min and 85°C to obtain the pretreated additive. Mix 4-maleimide-based phenol, potassium carbonate and DMF, purge with nitrogen, and stir at 200 r / min and 50°C while adding the pretreated additive. Heat to 80°C and react for 6 hours to obtain the modified additive.

[0036] Step A3: Linear low-density polyethylene, metallocene polyethylene rotomolded plastic, modified additives, dicumyl peroxide, modified filler and cassiterite catalyst are added to a twin-screw extruder and extruded and cooled under the following conditions: zone 1 temperature 80℃, zone 2 temperature 130℃, zone 3 temperature 180℃, zone 4 temperature 230℃, zone 5 temperature 230℃, and die head temperature 230℃, to obtain aging-resistant polyethylene rotomolded modified material.

[0037] The molar ratio of Si-Cl bonds on lithium dimethylsilanolate, trifluoropropylmethylcyclotrisiloxane and γ-chloropropyltrichlorosilane in step A1 is 1:3:1.

[0038] The molar ratio of Si-H bonds on the additive described in step A2 to 2,6-di-tert-butyl-4-vinylphenol is 1:1, the amount of chloroplatinic acid is 0.01% of the mass of 2,6-di-tert-butyl-4-vinylphenol, and the molar ratio of 4-maleimide-phenol, potassium carbonate and pretreatment additive is 1:1.1:1.

[0039] The weight ratio of linear low-density polyethylene, metallocene polyethylene molten plastic, modified additives, dicumyl peroxide, modified filler, and cassiterite catalyst mentioned in step A3 is 40:100:10:0.1:15:3, and the density of the linear low-density polyethylene is 0.939 g·cm³. -3 Melt index 5.8 g·(10 min) -1 The density of metallocene polyethylene rotomolded plastic is 0.933 g·cm³. -3 Melt index 5.8 g·(10 min) -1 .

[0040] The modified filler is prepared by the following steps: Step B1: Mix 2,4-dihydroxybenzophenone and ethanol, stir at 200 r / min and 0°C, add sodium hydroxide solution and dimethyl sulfate, heat to 25°C and react for 8 h to obtain intermediate 1. Add phosphorus oxychloride to the reaction vessel, stir at 80 r / min and 0°C, add DMF, heat to 25°C and react for 40 min, add intermediate 1, heat to 80°C and react for 5 h to obtain intermediate 2. Step B2: Intermediate 2 and dichloromethane were mixed evenly, and aluminum trichloride was added while stirring at 200 r / min and 25°C. The mixture was reacted for 6 h, cooled to 0°C, and the pH was adjusted to 5 to obtain intermediate 3. Zirconium tetrachloride was dissolved in DMF, and 2-aminoterephthalic acid and concentrated hydrochloric acid were added while stirring at 1000 r / min and 25°C. The mixture was stirred for 60 min, then the stirring was stopped and the temperature was raised to 120°C. The mixture was reacted for 25 h to obtain a zirconium organic framework. Step B3: Disperse the zirconium organic framework in ethanol, purge with nitrogen, stir at 300 r / min and 65 °C, add intermediate 3 and anhydrous magnesium sulfate, heat to 82 °C, reflux for 5 h to obtain the functionalized filler. Mix the functionalized filler, triethylamine and tetrahydrofuran evenly, purge with nitrogen, stir at 300 r / min and 3 °C, add dimethylchlorosilane, heat to 30 °C, react for 8 h to obtain the modified filler.

[0041] The ratio of 2,4-dihydroxybenzophenone, sodium hydroxide solution, and dimethyl sulfate used in step B1 is 4 mmol:5 mL:12 mmol, the concentration of sodium hydroxide solution is 2 mol / L, and the molar ratio of phosphorus oxychloride, DMF, and intermediate 1 is 5:8:4.

[0042] The molar ratio of intermediate 2 and aluminum trichloride in step B2 is 1:3, the ratio of zirconium tetrachloride, 2-aminoterephthalic acid and concentrated hydrochloric acid is 1 mmol:1 mmol:2 mL, and the mass fraction of concentrated hydrochloric acid is 36%.

[0043] In step B3, the molar ratio of amino groups, intermediate 3, and anhydrous magnesium sulfate on the zirconium organic framework is 1:1:1, and the molar ratio of phenolic hydroxyl groups, triethylamine, and dimethylchlorosilane on the functionalized filler is 2:1.1:1.

[0044] Comparative Example 1: In this comparative example, octamethylcyclotetrasiloxane was used instead of trifluoropropylmethylcyclotrisiloxane, while the other steps were the same as in Example 1.

[0045] Comparative Example 2: This comparative example uses an additive instead of a pretreatment additive, but the other steps are the same as in Example 1.

[0046] Comparative Example 3: This comparative example uses functionalized filler instead of modified filler, but the other steps are the same as in Example 1.

[0047] The modified materials from Examples 1-3 and Comparative Examples 1-3 were prepared into Type I specimens according to the standard GB / T10402-2006. Tensile strength was tested at a tensile speed of 50 mm / min. After aging at 135°C for 168 h, the tensile strength after heat aging was tested using an irradiation intensity of 600 W / m². 2 The cumulative irradiation from ultraviolet light was 400 kWh / m². 2 The tensile strength after photoaging was tested, and the tensile strength retention rate after photothermal aging was calculated. The test results are shown in Table 1 below.

[0048] Table 1 Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Thermal aging retention 98.44 98.52 98.61 91.35 92.35 96.71 Photo aging retention 98.03 98.49 98.83 89.54 97.97 95.59 As shown in Table 1, this application has excellent aging resistance.

[0049] The above description is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the concept of the invention or exceed the scope defined in the claims, they should all fall within the protection scope of the present invention.

Claims

1. A method for preparing an aging-resistant polyethylene rotational molding modified material, characterized in that: Specifically, the steps include the following: Step A1: Mix lithium dimethylsilyl alcohol and tetrahydrofuran evenly, purge with nitrogen, stir and add trifluoropropylmethylcyclotrisiloxane, heat and react, then add γ-chloropropyltrichlorosilane to react and obtain the additive. Step A2: Mix the additive, 2,6-di-tert-butyl-4-vinylphenol, chloroplatinic acid and DMF, purge with nitrogen, and react to obtain the pretreated additive. Mix 4-maleimide-based phenol, potassium carbonate and DMF, purge with nitrogen, stir and add the pretreated additive, heat and react to obtain the modified additive. Step A3: Linear low-density polyethylene, metallocene polyethylene rotomolded plastic, modified additives, dicumyl peroxide, modified filler and cassiterite catalyst are added to a twin-screw extruder, extruded and cooled to obtain aging-resistant polyethylene rotomolded modified material.

2. The method for preparing the aging-resistant polyethylene rotational molding modified material according to claim 1, characterized in that: The molar ratio of Si-Cl bonds on lithium dimethylsilanolate, trifluoropropylmethylcyclotrisiloxane and γ-chloropropyltrichlorosilane in step A1 is 1:3:

1.

3. The method for preparing the aging-resistant polyethylene rotational molding modified material according to claim 1, characterized in that: The molar ratio of Si-H bonds on the additive described in step A2 to 2,6-di-tert-butyl-4-vinylphenol is 1:1, and the molar ratio of 4-maleimide-based phenol, potassium carbonate, and pretreatment additive is 1:1.1:

1.

4. The method for preparing the aging-resistant polyethylene rotational molding modified material according to claim 1, characterized in that: The weight ratio of linear low-density polyethylene, metallocene polyethylene molten plastic, modified additives, dicumyl peroxide, modified filler and cassiterite catalyst mentioned in step A3 is 30-40:80-100:8-10:0.05-0.1:10-15:1-3.

5. The method for preparing the aging-resistant polyethylene rotational molding modified material according to claim 1, characterized in that: The modified filler is prepared by the following steps: Step B1: Mix 2,4-dihydroxybenzophenone and ethanol, stir and add sodium hydroxide solution and dimethyl sulfate, heat and react to obtain intermediate 1. Add phosphorus oxychloride to the reaction vessel, stir and add DMF, heat and react, add intermediate 1, and continue the reaction to obtain intermediate 2. Step B2: Mix intermediate 2 and dichloromethane and add aluminum trichloride to react. Adjust the pH to acidic to obtain intermediate 3. Dissolve zirconium tetrachloride in DMF, stir and add 2-aminoterephthalic acid and concentrated hydrochloric acid. After stirring, stop stirring and heat the reaction to obtain zirconium organic framework. Step B3: Disperse the zirconium organic framework in ethanol, purge with nitrogen, stir and add intermediate 3 and anhydrous magnesium sulfate, heat and reflux to obtain the functionalized filler. Mix the functionalized filler, triethylamine and tetrahydrofuran evenly, purge with nitrogen, stir and add dimethylchlorosilane, heat and react to obtain the modified filler.

6. The method for preparing the aging-resistant polyethylene rotational molding modified material according to claim 5, characterized in that: The ratio of 2,4-dihydroxybenzophenone, sodium hydroxide solution and dimethyl sulfate used in step B1 is 4 mmol:5 mL:12 mmol, and the molar ratio of phosphorus oxychloride, DMF and intermediate 1 is 5:8:

4.

7. The method for preparing the aging-resistant polyethylene rotational molding modified material according to claim 5, characterized in that: The molar ratio of intermediate 2 and aluminum trichloride in step B2 is 1:3, and the ratio of zirconium tetrachloride, 2-aminoterephthalic acid and concentrated hydrochloric acid is 1 mmol:1 mmol:2 mL.

8. The method for preparing the aging-resistant polyethylene rotational molding modified material according to claim 5, characterized in that: In step B3, the molar ratio of amino groups, intermediate 3, and anhydrous magnesium sulfate on the zirconium organic framework is 1:1:1, and the molar ratio of phenolic hydroxyl groups, triethylamine, and dimethylchlorosilane on the functionalized filler is 2:1.1:

1.

9. A type of aging-resistant polyethylene rotational molding modified material, characterized in that: Prepared according to any one of the preparation methods described in claims 1-8.