An environment-friendly flame-retardant pipe and its preparation method

Abstract

The present invention relates to the field of flame retardant materials, and specifically relates to an environment-friendly flame retardant pipe and a preparation method thereof. The environment-friendly flame retardant pipe, calculated by weight parts, comprises: 75-95 parts of polypropylene, 13-26 parts of maleic anhydride grafted polypropylene, 10-20 parts of activated calcium carbonate, 15-25 parts of environment-friendly flame retardant, 2-4 parts of lubricant, 1.5-3 parts of antioxidant, 0.8-1.6 parts of light stabilizer and 1.2-2.4 parts of heat stabilizer; the environment-friendly flame retardant is prepared by the combined reaction of vinylsulfonamide sulfadiazine and mercaptozirconium phosphate. The flame retardant pipe prepared by the present invention not only has environmental protection and excellent flame retardancy, but also has higher strength and better impact resistance performance than traditional polypropylene flame retardant pipes, thereby making the flame retardant pipe more durable, having a longer service life, reducing the replacement frequency and related maintenance costs.

Description

Technical Field

[0001] The invention relates to the field of flame retardant materials, and in particular to an environmentally friendly flame retardant pipe and a preparation method thereof. Background Art

[0002] Flame retardant pipes are suitable for conveying liquids with general working pressure in the fields of industry, agriculture, food, medicine, civil engineering, fishery, aquaculture, garden irrigation, etc. Such as: pneumatic pipes, hydraulic pipes, garden hoses, oil and water pipelines, oil exploration pipes, sandblasting pipes, peristaltic pump hoses, industrial robots, pneumatic tools, assembly plant air pressure tools, pressure conveying pipelines, can be used as vacuum straws, protective jackets or decorations for metal and electronic products. Among them, polypropylene flame retardant pipes are the most commonly used varieties. Polypropylene (PP) is a lightweight, corrosion-resistant, aging-resistant, and easy-to-install material. It is widely used in many fields due to its excellent mechanical properties, easy processing and low cost. However, since polypropylene is easy to burn when exposed to open flames, high temperatures or oxygen, it will emit black smoke and toxic gases when burning, which will have adverse effects on the human body and the environment. Therefore, flame retardants are usually added to improve its flame retardant properties.

[0003] At present, there are many studies and reports on polypropylene materials with high flame retardancy on the market, and the flame retardants involved mainly include halogen, phosphorus, nitrogen, nitrogen-phosphorus composite and inorganic flame retardants. However, halogen flame retardants are not environmentally friendly, and other types of flame retardants also have the defects of poor flame retardant effect or poor compatibility with polypropylene, which leads to the inability to achieve satisfactory results in the application of polypropylene. Therefore, it is extremely important to find a flame retardant material that can maintain the high performance of polypropylene while ensuring flame retardancy. Summary of the invention

[0004] In view of the problems existing in the prior art, the object of the present invention is to provide an environmentally friendly flame retardant tube and a preparation method thereof.

[0005] The purpose of the present invention is achieved by adopting the following technical solutions:

[0006] In a first aspect, the present invention provides an environmentally friendly flame-retardant tube, calculated by weight, comprising:

[0007] 75-95 parts of polypropylene, 13-26 parts of maleic anhydride grafted polypropylene, 10-20 parts of activated calcium carbonate, 15-25 parts of environmentally friendly flame retardant, 2-4 parts of lubricant, 1.5-3 parts of antioxidant, 0.8-1.6 parts of light stabilizer and 1.2-2.4 parts of heat stabilizer.

[0008] Preferably, the density of the polypropylene is 0.943-0.958 g / cm 3 , the melt index is 1.2-3.6g / 10min (190℃, 2.16kg).

[0009] Preferably, the grafting rate of the maleic anhydride grafted polypropylene PP-g-MAH is 0.8-1.2%, and the density is 0.912-0.926 g / cm 3 , and the melt index is 50-80 g / 10 min (190 °C, 2.16 kg).

[0010] Preferably, the activated calcium carbonate is calcium carbonate activated by a silane coupling agent; among them, the silane coupling agent is one of KH550, KH560, and KH570.

[0011] Preferably, the preparation process of the activated calcium carbonate includes:

[0012] Mix calcium carbonate fine powder of 5-8 μm and a silane coupling agent in an ethanol solution with a mass fraction of 30%-50%, reflux at 75-85 °C for 3-10 h. After the treatment, centrifuge to separate the solid, wash it three times with water and then dry it under vacuum to obtain the activated calcium carbonate;

[0013] Among them, the mass-volume ratio of the calcium carbonate fine powder, the silane coupling agent and the ethanol solution is 1 g: (0.1-0.5) g: (10-20) mL.

[0014] Preferably, the environmental protection flame retardant is prepared by the combined reaction of vinylsulfonamidated sulfadiazine and mercapto-phosphated zirconium.

[0015] Preferably, the lubricant is one or a mixture of zinc stearate, calcium stearate, liquid paraffin, oxidized polyethylene wax, and ethylene bisstearamide.

[0016] Preferably, the antioxidant is one or a mixture of antioxidant 168, antioxidant 626, antioxidant 1076, and antioxidant 1010.

[0017] Preferably, the light stabilizer is a hindered amine light stabilizer, including one or a mixture of light stabilizer 622, light stabilizer 770, light stabilizer 783, and light stabilizer 944.

[0018] Preferably, the heat stabilizer is an organotin heat stabilizer, including one or a mixture of dioctyltin dilaurate, dibutyltin maleate, bis(monobutyl maleate) dibutyltin, dioctyltin maleate, and bis(monooctyl maleate) dibutyltin.

[0019] Preferably, the preparation method of the environmental protection flame retardant includes:

[0020] S1. Weigh zirconium phosphate powder and ethanol solution and mix them. After fully dispersing in an ultrasonic disperser, add mercapto silane coupling agent, and stir in a water bath at 60 - 80 °C for 5 - 10 h. After the reaction is completed, separate, wash, and dry to obtain mercapto - functionalized zirconium phosphate ZP - SH.

[0021] S2. Weigh sulfadiazine, triethylamine, and sodium hydroxide solution and mix them in a beaker. Stir and disperse evenly at room temperature to obtain a sulfadiazine mixture. Weigh 4 - vinylbenzenesulfonyl chloride and acetone and mix them in a flask. Dropwise add the sulfadiazine mixture. After the addition is completed, raise the temperature to 70 - 90 °C and reflux and stir for 10 - 20 h. After the reaction ends, remove the solvent, wash, and dry to obtain vinylsulfonamide - functionalized sulfadiazine.

[0022] S3. Weigh mercapto - functionalized zirconium phosphate and vinylsulfonamide - functionalized sulfadiazine respectively and add them to dimethyl sulfoxide. Stir and disperse evenly at room temperature, add a photo - initiator, and stir and react under the irradiation of an LED ultraviolet lamp for 0.5 - 1.5 h. After the reaction ends, remove the solvent under reduced pressure to obtain an environmentally friendly flame retardant.

[0023] Preferably, in S1, the particle size of zirconium phosphate powder (Zn3B2O6, ZP) is 12 - 18 μm, and the manufacturer is Shandong Yueyang New Materials Co., Ltd.

[0024] Preferably, in S1, the mass - to - volume ratio of zirconium phosphate powder, mercapto silane coupling agent, and absolute ethanol is 10 g:(1.3 - 2.6) g:(50 - 100) mL.

[0025] Preferably, in S1, the mercapto silane coupling agent is one or more of γ - mercaptopropyltrimethoxysilane, γ - mercaptopropyltriethoxysilane, and γ - mercaptopropylmethyldimethoxysilane.

[0026] Preferably, in the sulfadiazine mixture of S2, the concentration of the sodium hydroxide solution is 0.1 - 0.6 mol / L, and the mass - to - volume ratio of sulfadiazine, triethylamine, and sodium hydroxide solution is (2.5 - 7.5) g:(1 - 2) g:(30 - 50) mL.

[0027] Preferably, in S2, the mass - to - volume ratio of 4 - vinylbenzenesulfonyl chloride, acetone, and sulfadiazine mixture is (2.1 - 6.3) g:(15 - 25) mL:(35 - 55) mL.

[0028] Preferably, in S2, the stirring speed is 250 - 450 r / min, and the dropping speed is 3 - 10 mL / min.

[0029] Preferably, in the step S3, the mass-volume ratio of zirconium phosphate mercaptan, vinylsulfonamide sulfadiazine and dimethyl sulfoxide is 1 g:(0.34 - 0.68) g:(15 - 25) mL.

[0030] Preferably, in the step S3, the photoinitiator is benzoin dimethyl ether, and the addition amount is 2% - 8% of the mass of vinylsulfonamide sulfadiazine.

[0031] Preferably, in the step S3, the wavelength of the LED ultraviolet lamp is 325 - 390 nm, and the light intensity is 1.5 - 2.5 mW / cm 2 。

[0032] In the second aspect, the present invention provides a preparation method of an environment-friendly flame-retardant pipe, including the following steps:

[0033] Step 1, weigh each raw material according to the weight parts, and then mix the raw materials in a blender and fully stir and mix at a speed of 500 - 800 r / min to obtain a mixed raw material;

[0034] Step 2, introduce the mixed raw material into a twin-screw extruder and extrude and pelletize in the range of 175 - 205 °C to obtain a flame-retardant material masterbatch;

[0035] Step 3, place the flame-retardant material masterbatch in a mold for processing and forming to finally obtain an environment-friendly flame-retardant pipe.

[0036] The beneficial effects of the present invention are as follows:

[0037] 1. The present invention prepares an environment-friendly flame-retardant pipe, which is obtained by processing and forming with a flame-retardant material masterbatch. The flame-retardant pipe prepared by the present invention not only has environmental friendliness and excellent flame retardancy, but also has higher strength and better impact resistance performance than traditional polypropylene flame-retardant pipes, thus making the flame-retardant pipe more durable, with a longer service life, reducing the replacement frequency and related maintenance costs.

[0038] 2. The flame-retardant material masterbatch prepared by the present invention uses polypropylene with light weight, good heat resistance and high chemical stability as the main material; activated calcium carbonate as the main filler to improve the rigidity, heat resistance and dimensional stability of polypropylene, while reducing costs; adding maleic anhydride grafted polypropylene enhances the adhesion and compatibility of polypropylene with polar materials; adding an environment-friendly flame retardant not only improves the flame retardant performance of polypropylene, but also enhances various performance manifestations of polypropylene; in addition, a variety of additives are also added to assist in enhancing the performance manifestations of polypropylene.

[0039] 3. The environmentally friendly flame retardant used in the present invention is prepared by using mercapto-phosphated zirconium as the matrix and reacting it with vinylsulfonamidated sulfadiazine through a thiol-double bond click reaction. Vinylsulfonamidated sulfadiazine is obtained by reacting sulfadiazine with 4-vinylbenzenesulfonyl chloride through an acyl chloride-amine binding reaction. Among them, sulfadiazine provides the amino group, which combines with the sulfonyl chloride in 4-vinylbenzenesulfonyl chloride to form a sulfonamide group, thereby obtaining vinylsulfonamidated sulfadiazine.

[0040] 4. In the process of preparing the environmentally friendly flame retardant of the present invention, since vinylsulfonamidated sulfadiazine contains more sulfonamide groups in its structure than sulfadiazine, and the vinyl group forms a thioether group after combining with mercapto-phosphated zirconium, the prepared flame retardant has better flame retardancy. After testing, it is found that the flame retardant also has a certain degree of improvement in the physical properties of polypropylene. Brief Description of the Drawings

[0041] The present invention will be further described with reference to the accompanying drawings. However, the embodiments in the drawings do not constitute any limitation to the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to the following drawings.

[0042] Figure 1 It is a scanning electron microscope schematic diagram of the environmentally friendly flame retardant prepared in Example 1 of the present invention. Detailed Description of the Embodiments

[0043] The technical solutions of the present invention will be described below through specific specific examples. It should be understood that one or more method steps mentioned in the present invention do not exclude the existence of other method steps before and after the combined steps or the insertion of other method steps between these clearly mentioned steps; it should also be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. Moreover, unless otherwise stated, the numbers of the method steps are only convenient tools for identifying the method steps, rather than limiting the arrangement order of the method steps or the scope that the present invention can be implemented. The change or adjustment of their relative relationship, without substantial change in the technical content, should also be regarded as the scope that the present invention can be implemented.

[0044] In order to better understand the above technical solutions, the exemplary embodiments of the present invention will be described in more detail below. Although the exemplary embodiments of the present invention are shown, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present invention and to be able to convey the scope of the present invention completely to those skilled in the art.

[0045] The present invention will be further described below in conjunction with the following embodiments. Example 1

[0046] An environmentally friendly flame-retardant pipe, calculated by weight parts, includes:

[0047] 85 parts of polypropylene, 18 parts of maleic anhydride grafted polypropylene, 15 parts of activated calcium carbonate, 20 parts of environmentally friendly flame retardant, 3 parts of lubricant, 2.1 parts of antioxidant, 1.2 parts of light stabilizer and 1.8 parts of heat stabilizer.

[0048] Among them, the density of polypropylene is 0.947 g / cm 3 , and the melt index is 2.4 g / 10 min (190 °C, 2.16 kg); the grafting rate of maleic anhydride grafted polypropylene PP-g-MAH is 1%, and the density is 0.918 g / cm 3 , and the melt index is 65 g / 10 min (190 °C, 2.16 kg); the lubricant is zinc stearate; the antioxidant is antioxidant 168; the light stabilizer is light stabilizer 622; the heat stabilizer is dioctyltin dilaurate.

[0049] Among them, the preparation process of the activated calcium carbonate includes:

[0050] Mix 1 g of calcium carbonate fine powder with a particle size of 5-8 μm and 0.3 g of KH550 in 15 mL of 40 wt% ethanol solution, reflux at 80 °C for 6 h. After the treatment, centrifuge to separate the solid, wash it three times with water and then dry it under vacuum to obtain activated calcium carbonate.

[0051] Among them, the preparation method of the environmentally friendly flame retardant includes:

[0052] S1. Weigh zirconium phosphate powder (ZP) and mix it with 50 wt% ethanol solution. After fully dispersing it in an ultrasonic disperser, add γ-mercaptopropyltrimethoxysilane. The mass-volume ratio of zirconium phosphate powder, γ-mercaptopropyltrimethoxysilane and absolute ethanol is 10 g:2.1 g:80 mL. Stir in a water bath at 70 °C for 8 h. After the reaction is completed, separate the solid and wash it with alcohol at least three times, and dry it under vacuum to obtain mercapto-functionalized zirconium phosphate (ZP-SH);

[0053] S2. Weigh sulfadiazine (SD), triethylamine (TEA) and 0.5 mol / L sodium hydroxide solution and mix them in a beaker. The mass-volume ratio of sulfadiazine, triethylamine and sodium hydroxide solution is 5 g: 1.5 g: 40 mL. Stir and disperse evenly at room temperature to obtain a sulfadiazine mixture. Weigh 4-vinylbenzenesulfonyl chloride (p-VSCl) and acetone and mix them in a flask. Introduce nitrogen as a protective gas. Under the condition of room temperature, dropwise add the sulfadiazine mixture at a dropping rate of 8 mL / min while stirring at a stirring speed of 350 r / min. The mass-volume ratio of 4-vinylbenzenesulfonyl chloride, acetone and sulfadiazine mixture is 4.2 g: 20 mL: 45 mL. After the dropping is completed, raise the temperature to 80 °C and reflux and stir for 15 h. After the reaction is completed, first remove the solvent by rotary evaporation, then wash the product with 5% (mass fraction) brine until the washing liquid is neutral, and then wash it three times with pure water and dry it under vacuum to obtain vinylsulfonamidated sulfadiazine (VSN-SD).

[0054] S3. Weigh zirconium phosphate sulfhydryl (ZP-SH) and vinylsulfonamidated sulfadiazine (VSN-SD) respectively and add them to dimethyl sulfoxide (DMSO). The mass-volume ratio of zirconium phosphate sulfhydryl, vinylsulfonamidated sulfadiazine and dimethyl sulfoxide is 1 g: 0.51 g: 20 mL. Stir and disperse evenly at room temperature, add 5% (by mass of vinylsulfonamidated sulfadiazine) benzoin dimethyl ether (DMPA) as a photoinitiator, and stir and react under the irradiation of an LED ultraviolet lamp with a wavelength of 365 nm and an illumination intensity of 2 mW / cm 2 for 1 h. After the reaction is completed, remove the solvent under reduced pressure to obtain an environmentally friendly flame retardant.

[0055] The preparation method of the above environmentally friendly flame retardant pipe includes the following steps:

[0056] Step 1. Calculate and weigh each raw material according to weight parts, and then mix each raw material in a mixer and fully stir and mix at a speed of 650 r / min to obtain a mixed raw material.

[0057] Step 2. Introduce the mixed raw material into a twin-screw extruder and extrude and pelletize in the range of 175 - 205 °C to obtain a flame retardant masterbatch.

[0058] Step 3. Place the flame retardant masterbatch in a mold for processing and forming to finally obtain an environmentally friendly flame retardant pipe. Example 2

[0059] An environmentally friendly flame retardant pipe, calculated according to weight parts, includes:

[0060] 75 parts of polypropylene, 13 parts of maleic anhydride grafted polypropylene, 10 parts of activated calcium carbonate, 15 parts of environmentally friendly flame retardant, 2 parts of lubricant, 1.5 parts of antioxidant, 0.8 part of light stabilizer and 1.2 parts of heat stabilizer.

[0061] The density of polypropylene is 0.947 g / cm 3 , and the melt index is 2.4 g / 10 min (190 °C, 2.16 kg); the grafting rate of maleic anhydride grafted polypropylene PP-g-MAH is 1%, and the density is 0.918 g / cm 3 , and the melt index is 65 g / 10 min (190 °C, 2.16 kg); the lubricant is liquid paraffin; the antioxidant is antioxidant 626; the light stabilizer is light stabilizer 770; the heat stabilizer is dibutyltin maleate.

[0062] Among them, the preparation process of the activated calcium carbonate includes:

[0063] Mix calcium carbonate micropowder of 5 - 8 μm and KH560 in an ethanol solution with a mass fraction of 30% - 50%. The mass-volume ratio of calcium carbonate micropowder, KH560 and ethanol solution is 1 g:0.1 g:10 mL. Reflux at 75 °C for 3 h. After the treatment, centrifuge to separate the solid, wash it three times with water and then dry it under vacuum to obtain activated calcium carbonate.

[0064] Among them, the preparation method of the environmentally friendly flame retardant includes:

[0065] S1. Weigh zirconium phosphate powder (ZP) and mix it with a 50 wt% ethanol solution. After fully dispersing it in an ultrasonic disperser, add γ-mercaptopropyltriethoxysilane. The mass-volume ratio of zirconium phosphate powder, γ-mercaptopropyltriethoxysilane and absolute ethanol is 10 g:1.3 g:50 mL. Stir in a water bath at 70 °C for 8 h. After the reaction is completed, separate the solid and wash it with alcohol at least three times, and dry it under vacuum to obtain mercapto-functionalized zirconium phosphate (ZP-SH);

[0066] S2. Weigh sulfadiazine (SD), triethylamine (TEA) and 0.1 mol / L sodium hydroxide solution and mix them in a beaker. The mass volume ratio of sulfadiazine, triethylamine and sodium hydroxide solution is 2.5 g:1 g:30 mL. Stir and disperse them evenly at room temperature to obtain a sulfadiazine mixed solution. Weigh 4-vinylbenzenesulfonyl chloride (p-VSCl) and acetone and mix them in a flask. Pass nitrogen as a protective gas. At room temperature, add the sulfadiazine mixed solution drop by drop at a rate of 3 mL / min. n, adding dropwise while stirring, the stirring speed is 250r / min, the mass volume ratio of the mixed solution of 4-vinylbenzenesulfonyl chloride, acetone and sulfadiazine is 2.1g:15mL:35mL, after the addition is completed, the temperature is raised to 70°C, refluxed and stirred for 10h, after the reaction is completed, the solvent is first removed by rotary evaporation, and then the product is washed with 5% saline solution until the washing liquid is neutral, and then washed with pure water three times, and dried under vacuum to obtain vinyl sulfonamidated sulfadiazine (VSN-SD);

[0067] S3. Weigh zirconium thiophosphate (ZP-SH) and vinyl sulfonamidated sulfadiazine (VSN-SD) respectively and add them into dimethyl sulfoxide (DMSO). The mass volume ratio of zirconium thiophosphate, vinyl sulfonamidated sulfadiazine and DMSO is 1g:0.34g:15mL. Stir and disperse them evenly at room temperature. Add 2% of the mass of vinyl sulfonamidated sulfadiazine dimethyl ether (DMPA) as a photoinitiator at a wavelength of 365nm and a light intensity of 1.5mW / cm 2 The reaction was stirred for 0.5 h under the irradiation of LED ultraviolet light. After the reaction was completed, the solvent was removed under reduced pressure to obtain an environmentally friendly flame retardant.

[0068] The method for preparing the above-mentioned environmentally friendly flame-retardant tube comprises the following steps:

[0069] Step 1, weighing each raw material according to the weight, then mixing each raw material in a blender, and fully blending at a speed of 500 r / min to obtain a mixed raw material;

[0070] Step 2, introducing the mixed raw materials into a twin-screw extruder, extruding and granulating at a temperature of 175-205° C. to obtain a flame retardant material masterbatch;

[0071] Step 3, placing the flame retardant material masterbatch in a mold for processing and molding, and finally obtaining an environmentally friendly flame retardant tube. Example 3

[0072] An environmentally friendly flame retardant tube, calculated by weight, comprising:

[0073] 95 parts of polypropylene, 26 parts of maleic anhydride grafted polypropylene, 20 parts of activated calcium carbonate, 25 parts of environmental protection flame retardant, 4 parts of lubricant, 3 parts of antioxidant, 1.6 parts of light stabilizer and 2.4 parts of heat stabilizer.

[0074] The density of polypropylene is 0.947 g / cm 3 , and the melt index is 2.4 g / 10 min (190 °C, 2.16 kg); the grafting rate of maleic anhydride grafted polypropylene PP-g-MAH is 1%, and the density is 0.918 g / cm 3 , and the melt index is 65 g / 10 min (190 °C, 2.16 kg); the lubricant is polyethylene wax oxide; the antioxidant is antioxidant 1076; the light stabilizer is light stabilizer 783; the heat stabilizer is bis(maleic acid monooctyl ester) dibutyltin.

[0075] The preparation process of the activated calcium carbonate includes:

[0076] Mix calcium carbonate micropowder of 5 - 8 μm and KH570 in an ethanol solution with a mass fraction of 30% - 50%. The mass-volume ratio of calcium carbonate micropowder, KH570 and ethanol solution is 1 g:0.5 g:20 mL. Reflux at 85 °C for 10 h. After the treatment, centrifuge to separate the solid, wash it three times with water and then dry it under vacuum to obtain the activated calcium carbonate.

[0077] Among them, the preparation method of the environmental protection flame retardant includes:

[0078] S1. Weigh zirconium phosphate powder (ZP) and mix it with a 50 wt% ethanol solution. After fully dispersing it in an ultrasonic disperser, add γ-mercaptopropylmethyldimethoxysilane. The mass-volume ratio of zirconium phosphate powder, γ-mercaptopropylmethyldimethoxysilane and absolute ethanol is 10 g:2.6 g:100 mL. Stir in a water bath at 70 °C for 8 h. After the reaction is completed, separate the solid and wash it with alcohol at least three times, and dry it under vacuum to obtain mercapto-functionalized zirconium phosphate (ZP-SH);

[0079] S2. Weigh sulfadiazine (SD), triethylamine (TEA) and 0.6 mol / L sodium hydroxide solution and mix them in a beaker. The mass volume ratio of sulfadiazine, triethylamine and sodium hydroxide solution is 7.5 g:2 g:50 mL. Stir and disperse them evenly at room temperature to obtain a sulfadiazine mixed solution. Weigh 4-vinylbenzenesulfonyl chloride (p-VSCl) and acetone and mix them in a flask. Pass nitrogen as a protective gas. At room temperature, add the sulfadiazine mixed solution drop by drop at a dropping speed of 10 mL / m in, adding dropwise while stirring, the stirring speed is 450r / min, the mass volume ratio of the mixed solution of 4-vinylbenzenesulfonyl chloride, acetone and sulfadiazine is 6.3g:25mL:55mL, after the addition is completed, the temperature is raised to 90°C, refluxed and stirred for 20h, after the reaction is completed, the solvent is first removed by rotary evaporation, and then the product is washed with 5% saline solution until the washing liquid is neutral, and then washed with pure water three times, and dried under vacuum to obtain vinyl sulfonamidated sulfadiazine (VSN-SD);

[0080] S3. Weigh zirconium thiophosphate (ZP-SH) and vinyl sulfonamidated sulfadiazine (VSN-SD) respectively and add them into dimethyl sulfoxide (DMSO). The mass volume ratio of zirconium thiophosphate, vinyl sulfonamidated sulfadiazine and DMSO is 1g:0.68g:25mL. Stir and disperse them evenly at room temperature. Add 8% of the mass of vinyl sulfonamidated sulfadiazine dimethyl ether (DMPA) as a photoinitiator at a wavelength of 365nm and a light intensity of 2.5mW / cm 2 The reaction was stirred for 1.5 hours under the irradiation of LED ultraviolet light. After the reaction was completed, the solvent was removed under reduced pressure to obtain an environmentally friendly flame retardant.

[0081] The method for preparing the above-mentioned environmentally friendly flame-retardant tube comprises the following steps:

[0082] Step 1, weighing each raw material according to the weight, then mixing each raw material in a blender, and fully blending at a speed of 800 r / min to obtain a mixed raw material;

[0083] Step 2, introducing the mixed raw materials into a twin-screw extruder, extruding and granulating at a temperature of 175-205° C. to obtain a flame retardant material masterbatch;

[0084] Step 3, placing the flame retardant material masterbatch in a mold for processing and molding, and finally obtaining an environmentally friendly flame retardant tube.

[0085] Comparative Example 1

[0086] An environmentally friendly flame-retardant tube, which differs from Example 1 only in that the environmentally friendly flame retardant is replaced by zirconium phosphate powder (ZP).

[0087] Comparative Example 2

[0088] A flame-retardant composite material pipe, which is only different from that of Example 1 in that the environmentally friendly flame retardant is replaced with vinylsulfonamidated sulfadiazine (VSN-SD), and the preparation of vinylsulfonamidated sulfadiazine is the same as that of Example 1.

[0089] Comparative Example 3

[0090] A flame-retardant composite material pipe, which is only different from that of Example 1 in that the environmentally friendly flame retardant is replaced with a mixture of zirconium phosphate powder (ZP) and vinylsulfonamidated sulfadiazine (VSN-SD), and the mass ratio of zirconium phosphate powder to vinylsulfonamidated sulfadiazine is 1:0.51.

[0091] Experimental Example

[0092] Performance tests and comparisons were carried out on the composite material pipes prepared in Example 1 and Comparative Examples 1-3. The relevant test standards include: tensile strength referring to ISO 527-2:2012, notched Izod impact strength referring to ISO 179-1:2010, limiting oxygen index referring to ISO 4589-2:1996, flame retardant rating referring to ANSI / UL-94-1985, UV aging treatment: referring to the standard of GB / T 16422.3-2014, the material was cycled (8 h light, 4 h dark) in a UVA-340 ultraviolet aging test chamber with parameters of 340 nm and 0.76 W / m 2 for 1500 h, and then the change rates of tensile strength, flexural modulus and notched impact strength after aging were detected. The test results are shown in Table 1:

[0093] Table 1 Performance test results of different environmentally friendly flame retardant pipes

[0094]

[0095] It can be seen from Table 1 that the environmentally friendly flame retardant pipe prepared in Example 1 not only has excellent flame retardancy, but also can maintain excellent mechanical properties, and its aging resistance performance is also excellent. In summary, it can be proved that the environmentally friendly flame retardant pipe prepared by the present invention has higher strength and better impact resistance performance than traditional polypropylene flame retardant pipes, the flame retardant pipe is more durable, has a longer service life, thereby reducing the replacement frequency and related maintenance costs.

[0096] In the description of this specification, the descriptions referring to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms should not be understood as necessarily referring to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine the different embodiments or examples described in this specification.

[0097] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. An environment-friendly flame-retardant pipe, characterized in that, Calculated by weight parts, it includes: 75 - 95 parts of polypropylene, 13 - 26 parts of maleic anhydride grafted polypropylene, 10 - 20 parts of activated calcium carbonate, 15 - 25 parts of environmental friendly flame retardant, 2 - 4 parts of lubricant, 1.5 - 3 parts of antioxidant, 0.8 - 1.6 parts of light stabilizer and 1.2 - 2.4 parts of heat stabilizer; The environmental friendly flame retardant is prepared by the combined reaction of vinylsulfonamide sulfadiazine and mercaptozirconium phosphate; The preparation method of the environmental friendly flame retardant includes: S1. Weigh zirconium phosphate powder and ethanol solution and mix them. After fully dispersing in an ultrasonic disperser, add mercapto silane coupling agent, and stir in a water bath at 60 - 80 °C for 5 - 10 h. After the reaction is completed, separate, wash and dry to obtain mercaptozirconium phosphate ZP - SH; S2. Weigh sulfadiazine, triethylamine and sodium hydroxide solution and mix them in a beaker, and stir and disperse evenly at room temperature to obtain a sulfadiazine mixture; Weigh 4 - vinylbenzenesulfonyl chloride and acetone and mix them in a flask, and dropwise add the sulfadiazine mixture drop by drop. After the addition is completed, raise the temperature to 70 - 90 °C, reflux and stir for 10 - 20 h. After the reaction ends, remove the solvent, wash and dry to obtain vinylsulfonamide sulfadiazine; S3. Weigh mercaptozirconium phosphate and vinylsulfonamide sulfadiazine respectively and add them to dimethyl sulfoxide, stir and disperse evenly at room temperature, add a photoinitiator, and stir and react under the irradiation of an LED ultraviolet lamp for 0.5 - 1.5 h. After the reaction ends, remove the solvent under reduced pressure to obtain the environmental friendly flame retardant.

2. The environmentally friendly flame retardant pipe according to claim 1, wherein, The density of the polypropylene is 0.943 - 0.958 g / cm 3 , and the melt index is 1.2 - 3.6 g / 10 min under the conditions of 190 °C and 2.16 kg; the grafting rate of the maleic anhydride grafted polypropylene PP-g-MAH is 0.8 - 1.2%, and the density is 0.912 - 0.926 g / cm 3 , and the melt index is 50 - 80 g / 10 min under the conditions of 190 °C and 2.16 kg.

3. An environment-friendly flame-retardant pipe according to claim 1, characterized in that, The activated calcium carbonate is calcium carbonate activated by a silane coupling agent; among them, the silane coupling agent is one of KH550, KH560, KH570.

4. An environment-friendly flame-retardant pipe according to claim 1, characterized in that, The lubricant is one or a mixture of zinc stearate, calcium stearate, liquid paraffin, oxidized polyethylene wax, ethylene bisstearamide; the antioxidant is one or a mixture of antioxidant 168, antioxidant 626, antioxidant 1076, antioxidant 1010.

5. An environment-friendly flame-retardant pipe according to claim 1, wherein, The light stabilizer is a hindered amine light stabilizer, including one or a mixture of light stabilizer 622, light stabilizer 770, light stabilizer 783, light stabilizer 944; the heat stabilizer is an organotin heat stabilizer, including one or a mixture of dioctyltin dilaurate, dibutyltin maleate, dibutyltin bis(monobutyl maleate), dioctyltin maleate, dibutyltin bis(monooctyl maleate).

6. The environmentally friendly flame retardant pipe according to claim 1, characterized in that, In S1, the mass - volume ratio of zirconium phosphate powder, mercapto silane coupling agent and absolute ethanol is 10 g:(1.3 - 2.6) g:(50 - 100) mL; the mercapto silane coupling agent is one or a mixture of γ - mercaptopropyltrimethoxysilane, γ - mercaptopropyltriethoxysilane, γ - mercaptopropylmethyldimethoxysilane.

7. An environment-friendly flame-retardant pipe according to claim 1, characterized in that, In the sulfadiazine mixture of S2, the concentration of the sodium hydroxide solution is 0.1 - 0.6 mol / L, and the mass-to-volume ratio of sulfadiazine, triethylamine, and the sodium hydroxide solution is (2.5 - 7.5) g : (1 - 2) g : (30 - 50) mL; in S2, the mass-to-volume ratio of 4-vinylbenzenesulfonyl chloride, acetone, and the sulfadiazine mixture is (2.1 - 6.3) g : (15 - 25) mL : (35 - 55) mL.

8. An environment-friendly flame-retardant pipe according to claim 1, characterized in that, In S3, the mass-to-volume ratio of mercaptozirconium phosphate, vinylsulfonamidated sulfadiazine, and dimethyl sulfoxide is 1 g : (0.34 - 0.68) g : (15 - 25) mL; the photoinitiator is benzoin dimethyl ether, and the addition amount is 2% - 8% of the mass of vinylsulfonamidated sulfadiazine.

9. A preparation method of the environment-friendly flame-retardant pipe according to claim 1, characterized in that, It includes the following steps: Step 1, calculate and weigh each raw material according to parts by weight, and then mix each raw material in a blender and fully stir and mix at a speed of 500 - 800 r / min to obtain a mixed raw material; Step 2, introduce the mixed raw material into a twin-screw extruder and extrude and pelletize in the range of 175 - 205 °C to obtain a flame-retardant material masterbatch; Step 3, place the flame-retardant material masterbatch in a mold for processing and forming to finally obtain an environment-friendly flame-retardant pipe.

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