A high-strength PE pipe and its preparation method

Abstract

The invention discloses a high-strength PE pipe and a preparation method thereof. The PE pipe comprises the following raw materials in parts by weight: 100-120 parts of PE masterbatch, 20-25 parts of modified resin, and 0.5-0.8 parts of dicumyl peroxide. When the raw materials are melt-blended, maleimide on the modified resin is grafted onto PE molecular chains. The modified resin is a polyurethane elastomer that can enhance the mechanical strength of the PE material. The modified resin contains a freely movable long-chain polysiloxane structure, which forms a semi-interpenetrating network structure with the PE molecular chains. The cross-linked PE molecules and the main chain grid of the modified resin molecules enhance the rigidity and strength of the material. The long-chain polysiloxane forms a synergistic effect through physical entanglement and interpenetrating structure, so that the material can disperse stress when subjected to force and avoid local damage. At the same time, the embedded cage-type silsesquioxane inside the material further enhances the mechanical properties of the material.

Description

Technical Field

[0001] The present invention relates to the technical field of PE pipe preparation, and in particular to a high-strength PE pipe and a preparation method thereof. Background Art

[0002] In recent years, plastic pipes have gradually replaced traditional pipes such as metal pipes, cement pipes, concrete pipes, rubber pipes, and fiberglass pipes. PE pipes, PP pipes, and PVC pipes are booming in the pipe market. PE pipes are odorless, tasteless, and non-toxic, and are not easily corroded by sewage, chemicals, and decaying substances in the soil. With their excellent performance, they have become a leader in the pipe market and are widely used in municipal water supply projects, marine aquaculture cages, and buried drainage projects. However, in some harsh environments, or when the load capacity is large or heavy, the compressive strength and tensile strength of PE pipes do not meet the corresponding requirements and cannot meet actual production and application. Summary of the Invention

[0003] The purpose of the present invention is to provide a high-strength PE pipe and a preparation method thereof, which solves the problem that the mechanical strength of PE pipes at present is not high.

[0004] The purpose of the present invention can be achieved through the following technical solutions:

[0005] A method for preparing a high-strength PE pipe comprises the following steps:

[0006] Step A1: Diphenylmethane diisocyanate, polytetramethylene glycol, and DMF are mixed, nitrogen is introduced, and the mixture is reacted at a speed of 120-150 r / min and a temperature of 55-60° C. for 10-15 minutes. A modifying additive is added and the reaction is continued for 15-20 minutes. 4-maleimidophenol and dibutyltin dilaurate are added and the reaction is continued for 10-15 minutes to obtain a modified resin;

[0007] Step A2: Weigh the following raw materials in parts by weight: 100-120 parts of PE masterbatch, 20-25 parts of modified resin, and 0.5-0.8 parts of dicumyl peroxide. Add the raw materials to a twin-screw extruder, and melt-extrude the extruder at a temperature of 150-160°C in zone 1, 170-180°C in zone 2, 180-190°C in zone 3, and 190-200°C at the die. Cool and shape the extruder to produce a high-strength PE pipe.

[0008] Furthermore, the weight ratio of diphenylmethane diisocyanate, polytetramethylene ether glycol, modifying additive and 4-maleimidophenol described in step A1 is 30:55:10:4.5, the amount of dibutyltin dilaurate is 2% of the mass of 4-maleimidophenol, and the relative molecular mass of polytetramethylene ether glycol is 1000.

[0009] Furthermore, the modified additive is prepared by the following steps:

[0010] Step B1: Bis(4-hydroxyphenyl) disulfide, boron trifluoride etherate and tetrahydrofuran are uniformly mixed, and epichlorohydrin is added under stirring at a speed of 200-300 r / min and a temperature of 65-70° C., and the reaction is carried out for 2-3 hours. Then, sodium hydroxide solution is added, the temperature is raised to 75-80° C., and the reaction is carried out for 3-5 hours to obtain intermediate 1. Intermediate 1, acrylic acid and propylene glycol methyl ether acetate are uniformly mixed, and tetrabutylammonium bromide is added under stirring at a speed of 120-150 r / min and a temperature of 70-75° C., and the reaction is carried out for 8-10 hours to obtain intermediate 2;

[0011] Step B2: Intermediate 2, trichlorosilane, chloroplatinic acid and DMF are mixed, nitrogen protection is introduced, and the reaction is carried out at a speed of 200-300 r / min and a temperature of 70-80°C for 6-8 hours to obtain a modifier. Dimethylhydrogen silicon alkoxide lithium and tetrahydrofuran are mixed uniformly, and octaphenylcyclotetrasiloxane is added while stirring at a speed of 120-150 r / min and a temperature of 0°C. The temperature is raised to 25-30°C, the reaction is carried out for 7-9 hours, and the modifier is added. The reaction is continued for 1-1.5 hours to obtain a modified polysiloxane.

[0012] Step B3: n-octyltrimethoxysilane, benzene and deionized water are mixed, stirred at a speed of 150-200 r / min and a temperature of 20-25° C. for 45-50 hours, and then a benzyltrimethylammonium hydroxide solution is added. The temperature is raised to 110-120° C. and the reaction is carried out for 20-24 hours to obtain a cage-type silsesquioxane. The cage-type silsesquioxane, tetrahydrofuran and tetraethylammonium hydride solution are mixed uniformly, reacted at a speed of 200-300 r / min and a temperature of 70-75° C. for 4-6 hours, and then hydrochloric acid is added for neutralization to obtain an incompletely condensed silsesquioxane.

[0013] Step B4: The incomplete condensed silsesquioxane, triethylamine and tetrahydrofuran are mixed evenly, nitrogen protection is introduced, and vinyltrichlorosilane is added under stirring at a speed of 120-150 r / min and a temperature of 0°C. The reaction is carried out for 1-1.5 hours, and then the temperature is raised to 20-25°C and the reaction is carried out for 3-5 hours to obtain a modified cage silsesquioxane. The modified cage silsesquioxane, modified polysiloxane, chloroplatinic acid and DMF are mixed evenly, nitrogen protection is introduced, and the reaction is carried out at a speed of 200-300 r / min and a temperature of 75-80°C for 6-8 hours to obtain a modified additive.

[0014] Furthermore, the amount ratio of bis(4-hydroxyphenyl) disulfide, boron trifluoride etherate, epichlorohydrin and sodium hydroxide solution described in step B1 is 30 mmol:60 mmol:0.9 g:6.5 mL, the mass fraction of sodium hydroxide solution is 25%, the molar ratio of intermediate 1 and acrylic acid is 1:2, and the amount of tetrabutylammonium bromide is 2% of the total mass of intermediate 1 and acrylic acid.

[0015] Furthermore, the molar ratio of the intermediate 2 and trichlorosilane described in step B2 is 1:2, the amount of chloroplatinic acid used is 1‰ of the mass of trichlorosilane, and the molar ratio of lithium dimethylhydrogensilanol, octaphenylcyclotetrasiloxane and the Si-Cl bond on the modifier is 2.8:1:2.

[0016] Further, the amount ratio of n-octyltrimethoxysilane, benzene, deionized water and benzyltrimethylammonium hydroxide solution in step B3 is 100 g: 500 mL: 40 mL: 16 mL, the benzyltrimethylammonium hydroxide solution is a methanol solution with a mass fraction of 15%, the amount ratio of cage silsesquioxane, tetrahydrofuran and tetraethylammonium hydride solution is 5 g: 125 mL: 2 mL, and the tetraethylammonium hydride solution is a 35% mass fraction aqueous solution.

[0017] Furthermore, the amount ratio of the incomplete condensed silsesquioxane, triethylamine, tetrahydrofuran and vinyltrichlorosilane described in step B4 is 2.5g:0.94g:25mL:0.5g, the molar ratio of the Si-H bond on the modified cage silsesquioxane and the modified polysiloxane is 1:1, and the amount of chloroplatinic acid is 1‰ of the mass of the modified cage silsesquioxane.

[0018] Beneficial effects of the present invention: A high-strength PE pipe disclosed in the present invention comprises the following raw materials: PE masterbatch, modified resin and dicumyl peroxide. The modified resin is prepared by reacting diphenylmethane diisocyanate and polytetramethylene ether glycol, then chain-extending with a modifying additive, and finally end-capping with 4-maleimidophenol.

[0019] The modified additive bis(4-hydroxyphenyl) disulfide and epichlorohydrin are reacted as raw materials, so that the hydroxyl group on the bis(4-hydroxyphenyl) disulfide reacts with the epoxy group of epichlorohydrin, and then a new epoxy group is formed by ring-closing under the action of sodium hydroxide solution to obtain intermediate 1. Intermediate 1 is reacted with acrylic acid, so that the epoxy group on intermediate 1 reacts with the carboxyl group on acrylic acid to obtain intermediate 2. Intermediate 2 is reacted with trichlorosilane, so that the double bond on intermediate 2 reacts with the silicon-hydrogen bond on trichlorosilane to obtain a modifier. Dimethyl hydrogen silicon alcohol lithium is used as an initiator and octaphenylcyclotetrasiloxane is used as a polymerization monomer to form a side chain containing A modified polysiloxane is prepared by hydrolyzing and condensing n-octyltrimethoxysilane to prepare a caged silsesquioxane, and the apex of the caged silsesquioxane is opened under the action of tetraethylammonium hydride to prepare an incompletely condensed silsesquioxane. The incompletely condensed silsesquioxane is reacted with vinyltrichlorosilane to react the silanol group on the incompletely condensed silsesquioxane with the chlorine atom site on the vinyltrichlorosilane to prepare a modified caged silsesquioxane. The modified caged silsesquioxane is reacted with a modified polysiloxane to react the double bond on the modified caged silsesquioxane with the silicon-hydrogen bond on the modified polysiloxane to prepare a modified additive.

[0020] When the raw materials are melt-blended, the maleimide on the modified resin and the PE molecular chain are grafted. The modified resin is a polyurethane elastomer that can enhance the mechanical strength of the PE material. The modified resin contains a long-chain polysiloxane structure that can move freely, which in turn forms a semi-interpenetrating network structure with the PE molecular chain. The cross-linked PE molecules and the modified resin molecular main chain grid enhance the rigidity and strength of the material. The long-chain polysiloxane forms a synergistic effect through physical entanglement and interpenetrating structure, which enables the material to disperse stress when subjected to force and avoid local damage. At the same time, the embedded cage-type silsesquioxane inside further improves the mechanical properties of the material. DETAILED DESCRIPTION

[0021] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0022] Example 1, a method for preparing a high-strength PE pipe, specifically comprising the following steps:

[0023] Step A1: Diphenylmethane diisocyanate, polytetramethylene glycol, and DMF were mixed, nitrogen was introduced, and the mixture was reacted at a speed of 120 r / min and a temperature of 55° C. for 10 minutes. A modifying additive was then added, and the reaction was continued for 15 minutes. 4-maleimidophenol and dibutyltin dilaurate were then added, and the reaction was continued for 10 minutes to obtain a modified resin.

[0024] Step A2: Weigh the following raw materials in parts by weight: 100 parts of PE masterbatch, 20 parts of modified resin, and 0.5 parts of dicumyl peroxide. Add the raw materials to a twin-screw extruder and melt-extrude at a temperature of 150°C in zone 1, 170°C in zone 2, 180°C in zone 3, and a die temperature of 190°C. Cool and shape to produce a high-strength PE pipe.

[0025] The weight ratio of diphenylmethane diisocyanate, polytetramethylene ether glycol, modifying additive and 4-maleimidophenol described in step A1 is 30:55:10:4.5, the amount of dibutyltin dilaurate is 2% of the mass of 4-maleimidophenol, and the relative molecular mass of polytetramethylene ether glycol is 1000.

[0026] The model of the PE masterbatch described in step A2 is PE100.

[0027] The modified additive is prepared by the following steps:

[0028] Step B1: Bis(4-hydroxyphenyl) disulfide, boron trifluoride etherate, and tetrahydrofuran were uniformly mixed, and epichlorohydrin was added under stirring at a speed of 200 r / min and a temperature of 65°C. The mixture was reacted for 2 hours, and then sodium hydroxide solution was added. The temperature was raised to 75°C, and the reaction was carried out for 3 hours to obtain intermediate 1. Intermediate 1, acrylic acid, and propylene glycol methyl ether acetate were uniformly mixed, and tetrabutylammonium bromide was added under stirring at a speed of 120 r / min and a temperature of 70°C. The mixture was reacted for 8 hours to obtain intermediate 2;

[0029] Step B2: Intermediate 2, trichlorosilane, chloroplatinic acid, and DMF were mixed, nitrogen was introduced, and the reaction was carried out at a speed of 200 r / min and a temperature of 70°C for 6 hours to obtain a modifier. Dimethylhydrogensilanol lithium and tetrahydrofuran were mixed uniformly, stirred at a speed of 120 r / min and a temperature of 0°C, and octaphenylcyclotetrasiloxane was added. The temperature was raised to 25°C, and the reaction was carried out for 7 hours. The modifier was then added and the reaction was continued for 1 hour to obtain a modified polysiloxane.

[0030] Step B3: n-octyltrimethoxysilane, benzene and deionized water were mixed, stirred at a speed of 150 r / min and a temperature of 20° C. for 45 hours, and then a benzyltrimethylammonium hydroxide solution was added. The temperature was raised to 110° C. and the reaction was carried out for 20 hours to obtain a cage-type silsesquioxane. The cage-type silsesquioxane, tetrahydrofuran and tetraethylammonium hydride solution were mixed uniformly, reacted at a speed of 200 r / min and a temperature of 70° C. for 4 hours, and then hydrochloric acid was added for neutralization to obtain an incompletely condensed silsesquioxane.

[0031] Step B4: The incomplete condensed silsesquioxane, triethylamine and tetrahydrofuran were mixed evenly, nitrogen was introduced for protection, and vinyltrichlorosilane was added under stirring at a speed of 120 r / min and a temperature of 0°C. After reacting for 1 hour, the temperature was raised to 20°C and the reaction was carried out for 3 hours to obtain a modified cage-type silsesquioxane. The modified cage-type silsesquioxane, modified polysiloxane, chloroplatinic acid and DMF were mixed evenly, nitrogen was introduced for protection, and the reaction was carried out at a speed of 200 r / min and a temperature of 75°C for 6 hours to obtain a modified additive.

[0032] The amount ratio of bis(4-hydroxyphenyl) disulfide, boron trifluoride etherate, epichlorohydrin and sodium hydroxide solution described in step B1 is 30mmol:60mmol:0.9g:6.5mL, the mass fraction of sodium hydroxide solution is 25%, the molar ratio of intermediate 1 and acrylic acid is 1:2, and the amount of tetrabutylammonium bromide is 2% of the total mass of intermediate 1 and acrylic acid.

[0033] The molar ratio of intermediate 2 and trichlorosilane described in step B2 is 1:2, the amount of chloroplatinic acid used is 1‰ of the mass of trichlorosilane, and the molar ratio of lithium dimethylhydrogensilanol, octaphenylcyclotetrasiloxane and Si-Cl bonds on the modifier is 2.8:1:2.

[0034] The amount ratio of n-octyltrimethoxysilane, benzene, deionized water and benzyltrimethylammonium hydroxide solution in step B3 is 100g:500mL:40mL:16mL, the benzyltrimethylammonium hydroxide solution is a methanol solution with a mass fraction of 15%, the amount ratio of cage silsesquioxane, tetrahydrofuran and tetraethylammonium hydride solution is 5g:125mL:2mL, and the tetraethylammonium hydride solution is a 35% mass fraction aqueous solution.

[0035] The amount ratio of the incomplete condensation silsesquioxane, triethylamine, tetrahydrofuran and vinyltrichlorosilane described in step B4 is 2.5g:0.94g:25mL:0.5g, the molar ratio of the Si-H bond on the modified cage silsesquioxane and the modified polysiloxane is 1:1, and the amount of chloroplatinic acid is 1‰ of the mass of the modified cage silsesquioxane.

[0036] Example 2, a method for preparing a high-strength PE pipe, specifically comprising the following steps:

[0037] Step A1: Diphenylmethane diisocyanate, polytetramethylene glycol, and DMF were mixed, nitrogen was introduced, and the mixture was reacted at a speed of 120 r / min and a temperature of 60° C. for 13 minutes. A modifying additive was then added, and the reaction was continued for 18 minutes. 4-maleimidophenol and dibutyltin dilaurate were then added, and the reaction was continued for 13 minutes to obtain a modified resin.

[0038] Step A2: Weigh the following raw materials in parts by weight: 110 parts of PE masterbatch, 23 parts of modified resin, and 0.6 parts of dicumyl peroxide. Add the raw materials to a twin-screw extruder and melt-extrude at a temperature of 155°C in zone 1, 175°C in zone 2, 185°C in zone 3, and a die temperature of 195°C. Cool and shape to produce a high-strength PE pipe.

[0039] The weight ratio of diphenylmethane diisocyanate, polytetramethylene ether glycol, modifying additive and 4-maleimidophenol described in step A1 is 30:55:10:4.5, the amount of dibutyltin dilaurate is 2% of the mass of 4-maleimidophenol, and the relative molecular mass of polytetramethylene ether glycol is 1000.

[0040] The model of the PE masterbatch described in step A2 is PE100.

[0041] The modified additive is prepared by the following steps:

[0042] Step B1: Bis(4-hydroxyphenyl) disulfide, boron trifluoride etherate, and tetrahydrofuran were uniformly mixed, and epichlorohydrin was added under stirring at a speed of 200 r / min and a temperature of 70°C. The mixture was reacted for 2 hours, and then sodium hydroxide solution was added. The temperature was raised to 80°C, and the reaction was carried out for 4 hours to obtain intermediate 1. Intermediate 1, acrylic acid, and propylene glycol methyl ether acetate were uniformly mixed, and tetrabutylammonium bromide was added under stirring at a speed of 120 r / min and a temperature of 75°C. The mixture was reacted for 9 hours to obtain intermediate 2;

[0043] Step B2: Intermediate 2, trichlorosilane, chloroplatinic acid, and DMF were mixed, nitrogen was introduced, and the reaction was carried out at a speed of 200 r / min and a temperature of 75°C for 7 hours to obtain a modifier. Dimethylhydrogensilanol lithium and tetrahydrofuran were mixed uniformly, stirred at a speed of 120 r / min and a temperature of 0°C, and octaphenylcyclotetrasiloxane was added. The temperature was raised to 30°C, and the reaction was carried out for 8 hours. The modifier was then added and the reaction was continued for 1.3 hours to obtain a modified polysiloxane.

[0044] Step B3: n-octyltrimethoxysilane, benzene and deionized water were mixed, stirred at a speed of 200 r / min and a temperature of 20° C. for 48 hours, and then a benzyltrimethylammonium hydroxide solution was added. The temperature was raised to 115° C. and the reaction was carried out for 22 hours to obtain a cage-type silsesquioxane. The cage-type silsesquioxane, tetrahydrofuran and tetraethylammonium hydride solution were mixed uniformly, reacted at a speed of 200 r / min and a temperature of 75° C. for 5 hours, and then hydrochloric acid was added for neutralization to obtain an incompletely condensed silsesquioxane.

[0045] Step B4: The incomplete condensation silsesquioxane, triethylamine and tetrahydrofuran were mixed evenly, nitrogen was introduced for protection, and vinyltrichlorosilane was added under stirring at a speed of 150 r / min and a temperature of 0°C. After reacting for 1 hour, the temperature was raised to 25°C and the reaction was carried out for 4 hours to obtain a modified cage-type silsesquioxane. The modified cage-type silsesquioxane, modified polysiloxane, chloroplatinic acid and DMF were mixed evenly, nitrogen was introduced for protection, and the reaction was carried out at a speed of 200 r / min and a temperature of 80°C for 7 hours to obtain a modified additive.

[0046] The amount ratio of bis(4-hydroxyphenyl) disulfide, boron trifluoride etherate, epichlorohydrin and sodium hydroxide solution described in step B1 is 30mmol:60mmol:0.9g:6.5mL, the mass fraction of sodium hydroxide solution is 25%, the molar ratio of intermediate 1 and acrylic acid is 1:2, and the amount of tetrabutylammonium bromide is 2% of the total mass of intermediate 1 and acrylic acid.

[0047] The molar ratio of intermediate 2 and trichlorosilane described in step B2 is 1:2, the amount of chloroplatinic acid used is 1‰ of the mass of trichlorosilane, and the molar ratio of lithium dimethylhydrogensilanol, octaphenylcyclotetrasiloxane and Si-Cl bonds on the modifier is 2.8:1:2.

[0048] The amount ratio of n-octyltrimethoxysilane, benzene, deionized water and benzyltrimethylammonium hydroxide solution in step B3 is 100g:500mL:40mL:16mL, the benzyltrimethylammonium hydroxide solution is a methanol solution with a mass fraction of 15%, the amount ratio of cage silsesquioxane, tetrahydrofuran and tetraethylammonium hydride solution is 5g:125mL:2mL, and the tetraethylammonium hydride solution is a 35% mass fraction aqueous solution.

[0049] The amount ratio of the incomplete condensation silsesquioxane, triethylamine, tetrahydrofuran and vinyltrichlorosilane described in step B4 is 2.5g:0.94g:25mL:0.5g, the molar ratio of the Si-H bond on the modified cage silsesquioxane and the modified polysiloxane is 1:1, and the amount of chloroplatinic acid is 1‰ of the mass of the modified cage silsesquioxane.

[0050] Example 3, a method for preparing a high-strength PE pipe, specifically comprising the following steps:

[0051] Step A1: Diphenylmethane diisocyanate, polytetramethylene glycol, and DMF were mixed, nitrogen was introduced, and the mixture was reacted at a speed of 150 r / min and a temperature of 60° C. for 15 minutes. A modifying additive was then added, and the reaction was continued for 20 minutes. 4-maleimidophenol and dibutyltin dilaurate were then added, and the reaction was continued for 15 minutes to obtain a modified resin.

[0052] Step A2: Weigh the following raw materials in parts by weight: 120 parts of PE masterbatch, 25 parts of modified resin, and 0.8 parts of dicumyl peroxide. Add the raw materials to a twin-screw extruder and melt-extrude at a temperature of 160°C in zone 1, 180°C in zone 2, 190°C in zone 3, and a die head temperature of 200°C. Cool and shape to produce a high-strength PE pipe.

[0053] The weight ratio of diphenylmethane diisocyanate, polytetramethylene ether glycol, modifying additive and 4-maleimidophenol described in step A1 is 30:55:10:4.5, the amount of dibutyltin dilaurate is 2% of the mass of 4-maleimidophenol, and the relative molecular mass of polytetramethylene ether glycol is 1000.

[0054] The model of the PE masterbatch described in step A2 is PE100.

[0055] The modified additive is prepared by the following steps:

[0056] Step B1: Bis(4-hydroxyphenyl) disulfide, boron trifluoride etherate, and tetrahydrofuran were mixed uniformly, and epichlorohydrin was added under stirring at a speed of 300 r / min and a temperature of 70°C. The mixture was reacted for 3 hours, and then sodium hydroxide solution was added. The temperature was raised to 80°C, and the reaction was carried out for 5 hours to obtain intermediate 1. Intermediate 1, acrylic acid, and propylene glycol methyl ether acetate were mixed uniformly, and tetrabutylammonium bromide was added under stirring at a speed of 150 r / min and a temperature of 75°C. The mixture was reacted for 10 hours to obtain intermediate 2;

[0057] Step B2: Intermediate 2, trichlorosilane, chloroplatinic acid, and DMF were mixed, nitrogen was introduced, and the reaction was carried out at a speed of 300 r / min and a temperature of 80°C for 8 hours to obtain a modifier. Dimethylsilanol lithium and tetrahydrofuran were mixed uniformly, stirred at a speed of 150 r / min and a temperature of 0°C, and octaphenylcyclotetrasiloxane was added. The temperature was raised to 30°C, and the reaction was carried out for 9 hours. The modifier was then added and the reaction was continued for 1.5 hours to obtain a modified polysiloxane.

[0058] Step B3: n-octyltrimethoxysilane, benzene and deionized water were mixed, stirred at a speed of 200 r / min and a temperature of 25°C for 50 hours, and then a benzyltrimethylammonium hydroxide solution was added. The temperature was raised to 120°C and the reaction was carried out for 24 hours to obtain a cage-type silsesquioxane. The cage-type silsesquioxane, tetrahydrofuran and tetraethylammonium hydride solution were mixed uniformly, reacted at a speed of 300 r / min and a temperature of 75°C for 6 hours, and then hydrochloric acid was added for neutralization to obtain an incompletely condensed silsesquioxane.

[0059] Step B4: The incomplete condensation silsesquioxane, triethylamine and tetrahydrofuran were mixed evenly, nitrogen was introduced for protection, and vinyltrichlorosilane was added under stirring at a speed of 150 r / min and a temperature of 0°C. The reaction was carried out for 1.5 hours, and then the temperature was raised to 25°C and the reaction was carried out for 5 hours to obtain a modified cage-type silsesquioxane. The modified cage-type silsesquioxane, modified polysiloxane, chloroplatinic acid and DMF were mixed evenly, nitrogen was introduced for protection, and the reaction was carried out at a speed of 300 r / min and a temperature of 80°C for 8 hours to obtain a modified additive.

[0060] The amount ratio of bis(4-hydroxyphenyl) disulfide, boron trifluoride etherate, epichlorohydrin and sodium hydroxide solution described in step B1 is 30mmol:60mmol:0.9g:6.5mL, the mass fraction of sodium hydroxide solution is 25%, the molar ratio of intermediate 1 and acrylic acid is 1:2, and the amount of tetrabutylammonium bromide is 2% of the total mass of intermediate 1 and acrylic acid.

[0061] The molar ratio of intermediate 2 and trichlorosilane described in step B2 is 1:2, the amount of chloroplatinic acid used is 1‰ of the mass of trichlorosilane, and the molar ratio of lithium dimethylhydrogensilanol, octaphenylcyclotetrasiloxane and Si-Cl bonds on the modifier is 2.8:1:2.

[0062] The amount ratio of n-octyltrimethoxysilane, benzene, deionized water and benzyltrimethylammonium hydroxide solution in step B3 is 100g:500mL:40mL:16mL, the benzyltrimethylammonium hydroxide solution is a methanol solution with a mass fraction of 15%, the amount ratio of cage silsesquioxane, tetrahydrofuran and tetraethylammonium hydride solution is 5g:125mL:2mL, and the tetraethylammonium hydride solution is a 35% mass fraction aqueous solution.

[0063] The amount ratio of the incomplete condensation silsesquioxane, triethylamine, tetrahydrofuran and vinyltrichlorosilane described in step B4 is 2.5g:0.94g:25mL:0.5g, the molar ratio of the Si-H bond on the modified cage silsesquioxane and the modified polysiloxane is 1:1, and the amount of chloroplatinic acid is 1‰ of the mass of the modified cage silsesquioxane.

[0064] Comparative Example 1: Compared with Example 1, ethylene glycol was used instead of bis(4-hydroxyphenyl) disulfide, and the remaining steps were the same.

[0065] Comparative Example 2: Compared with Example 1, this comparative example uses octamethylcyclotetrasiloxane instead of octaphenylcyclotetrasiloxane, and the remaining steps are the same.

[0066] Comparative Example 3: Compared with Example 1, this comparative example uses styrene instead of modified polysiloxane, and the remaining steps are the same.

[0067] The samples prepared in Examples 1-3 and Comparative Examples 1-3 were made into Type II specimens according to the standard of GB / T1040-2018, and the tensile strength was tested at a tensile rate of 20 mm / min. Notched Type A specimens were made according to GB / T1843-2008 to test the impact strength. The test results are shown in Table 1 below.

[0068] Table 1

[0069]

[0070] It can be seen from Table 1 that the present application has good mechanical strength.

[0071] The above content is merely an example and explanation of the concept of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a high-strength PE pipe, characterized by: The specific steps include: Step A1: Diphenylmethane diisocyanate, polytetramethylene glycol, and DMF are mixed, nitrogen is introduced for protection, and after reaction, a modification additive is added, the reaction is continued, 4-maleimidophenol and dibutyltin dilaurate are added, and the reaction is continued to obtain a modified resin; Step A2: Weigh the following raw materials in parts by weight: 100-120 parts of PE masterbatch, 20-25 parts of modified resin, and 0.5-0.8 parts of dicumyl peroxide, melt-extrude the raw materials, cool and shape them, and produce a high-strength PE pipe; The modified additive is prepared by the following steps: Step B1: Bis(4-hydroxyphenyl) disulfide, boron trifluoride etherate, and tetrahydrofuran are mixed and stirred, and epichlorohydrin is added. After reaction, sodium hydroxide solution is added, and the temperature is increased to continue the reaction to obtain Intermediate 1. Intermediate 1, acrylic acid, and propylene glycol methyl ether acetate are mixed and stirred, and tetrabutylammonium bromide is added to react to obtain Intermediate 2. Step B2: Intermediate 2, trichlorosilane, chloroplatinic acid, and DMF are mixed and reacted under nitrogen protection to obtain a modifier. Lithium dimethylhydrogensilanol and tetrahydrofuran are mixed and stirred, and octaphenylcyclotetrasiloxane is added. After the reaction, the modifier is added and the reaction is continued to obtain a modified polysiloxane. Step B3: After mixing n-octyltrimethoxysilane, benzene and deionized water, benzyltrimethylammonium hydroxide solution is added and the temperature is raised to react to obtain a cage-type silsesquioxane. After mixing the cage-type silsesquioxane, tetrahydrofuran and tetraethylammonium hydride solution, hydrochloric acid is added for neutralization to obtain an incompletely condensed silsesquioxane. Step B4: uniformly mix the incompletely condensed silsesquioxane, triethylamine and tetrahydrofuran, introduce nitrogen protection, stir and add vinyltrichlorosilane, and react to obtain a modified cage-type silsesquioxane; uniformly mix the modified cage-type silsesquioxane, modified polysiloxane, chloroplatinic acid and DMF, introduce nitrogen protection, and react to obtain a modified additive.

2. The method for preparing a high-strength PE pipe according to claim 1, characterized in that: The weight ratio of diphenylmethane diisocyanate, polytetramethylene ether glycol, modification additive and 4-maleimidophenol described in step A1 is 30:55:10:4.

5.

3. The method for preparing a high-strength PE pipe according to claim 1, characterized in that: The amount ratio of bis(4-hydroxyphenyl) disulfide, boron trifluoride etherate, epichlorohydrin and sodium hydroxide solution in step B1 is 30 mmol:60 mmol:0.9 g:6.5 mL, and the molar ratio of intermediate 1 to acrylic acid is 1:

2.

4. The method for preparing a high-strength PE pipe according to claim 1, characterized in that: The molar ratio of intermediate 2 and trichlorosilane described in step B2 is 1:2, the amount of chloroplatinic acid used is 1‰ of the mass of trichlorosilane, and the molar ratio of lithium dimethylhydrogensilanol, octaphenylcyclotetrasiloxane and Si-Cl bonds on the modifier is 2.8:1:

2.

5. The method for preparing a high-strength PE pipe according to claim 1, characterized in that: The amount ratio of n-octyltrimethoxysilane, benzene, deionized water and benzyltrimethylammonium hydroxide solution in step B3 is 100g:500mL:40mL:16mL, and the amount ratio of cage silsesquioxane, tetrahydrofuran and tetraethylammonium hydride solution is 5g:125mL:2mL.

6. The method for preparing a high-strength PE pipe according to claim 1, characterized in that: The amount ratio of the incompletely condensed silsesquioxane, triethylamine, tetrahydrofuran and vinyltrichlorosilane described in step B4 is 2.5g:0.94g:25mL:0.5g, and the molar ratio of Si-H bonds on the modified cage silsesquioxane and the modified polysiloxane is 1:

1.

7. A high-strength PE pipe, characterized by: Prepared according to any one of claims 1 to 6.

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