Flame-retardant high-toughness modified PP (polypropylene) material as well as preparation method and application thereof

Abstract

The invention relates to the technical field of polypropylene, and discloses a flame-retardant high-toughness modified PP material and a preparation method and application thereof.Melamine grafted POE elastomer, phosphorylated polyvinyl alcohol, polypropylene resin and the like are subjected to melt extrusion and grain-sized dicing, and the flame-retardant high-toughness modified PP material is obtained. The POE elastomer has a very good toughening effect on polypropylene, meanwhile, the POE elastomer is grafted with a melamine structure, and an amino group of the POE elastomer and a phosphoric acid matrix of phosphorylated polyvinyl alcohol form an ammonium phosphate structure, so that the compatibility between polyvinyl alcohol and polypropylene is improved, and the adverse effect of polyvinyl alcohol on the toughness and mechanical properties of polypropylene is reduced. The POE elastomer is grafted with a melamine structure as a gas source, and phosphorylated polyvinyl alcohol is used as an acid source and a carbon source to form an intumescent flame retardant, so that the flame retardant property of the polypropylene material is improved, the polypropylene material has higher limit oxygen index, and the prepared PP material has good practical application in the aspects of six-type network cable cross skeletons, wire sheath materials and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of polypropylene, in particular to a flame-retardant high-toughness modified PP material, a preparation method and applications thereof. Background Art

[0002] Polypropylene is a common thermoplastic polymer resin with low density, lightweight, high mechanical strength, chemical stability, and excellent heat resistance. It has important applications in wires and cables, furniture and appliances, medical devices, and other fields. However, conventional polypropylene resins have poor toughness and flame retardancy, hindering their practical application in network cables, wire sheathing materials, and the cross-ribbons of Category 6 network cables.

[0003] Polyvinyl alcohol undergoes intramolecular dehydration at high temperatures to form aromatic rings. This can be used as a carbon source and compounded with nitrogen- and phosphorus-based flame retardants, offering broad application prospects in polymer materials. Patent CN112390992B discloses a corrosion-resistant, flame-retardant cable sheathing material made from chlorinated polypropylene, nitrile rubber, polyvinyl alcohol, melamine phosphate, and polyolefin elastomers. The resulting cable sheathing material exhibits excellent mechanical and flame retardancy properties. However, polyvinyl alcohol has poor compatibility with polypropylene, which can affect the material's mechanical properties. Summary of the Invention

[0004] (1) Technical problems solved: In response to the deficiencies of the prior art, the present invention provides a flame-retardant and high-toughness modified PP material, a preparation method, and applications thereof, which solve the problems of poor flame retardancy and toughness of polypropylene.

[0005] (II) Technical solution: A method for preparing a flame-retardant and high-toughness modified PP material:

[0006] (1) The preparation method of phosphorylated polyvinyl alcohol is as follows: add polyvinyl alcohol, phosphoric acid and urea to water, heat to 50-60°C, stir for 7-10 hours, then heat to 90-100°C, stir for 3-5 hours, add ethanol, filter, wash with ethanol, purify, and dry to obtain phosphorylated polyvinyl alcohol.

[0007] (2) Ethylene-octene copolymer elastomer, 2,4-diamino-6-allylamino-1,3,5-triazine and diisopropylbenzene peroxide are mixed and placed in a twin-screw extruder for grafting reaction. The product is added into xylene, heated to reflux, stirred and then precipitated with acetone. The mixture is filtered, washed with acetone for purification, and then dried to obtain a melamine-grafted POE elastomer.

[0008] (3) Adding melamine-grafted POE elastomer and phosphorylated polyvinyl alcohol to water, stirring and drying to remove water, then adding the mixture with polypropylene resin and antioxidant into a mixer and mixing, then placing the mixture in a twin-screw extruder for melt extrusion and pelletizing to obtain a flame-retardant and high-toughness modified PP material.

[0009] Furthermore, in (1), the amount of polyvinyl alcohol used is 100 parts by weight, the amount of phosphoric acid is 160-240 parts by weight, and the amount of urea is 5-11 parts by weight.

[0010] Furthermore, in (2), the amount of the ethylene-octene copolymer elastomer is 100 parts by weight, the amount of 2,4-diamino-6-allylamino-1,3,5-triazine is 4-12 parts by weight, and the amount of dicumyl peroxide is 0.3-0.8 parts by weight.

[0011] Furthermore, the temperature of sections 1-6 of the screw extruder in (2) is 160-180° C., and the screw speed is 50-80 r / min.

[0012] Furthermore, in (3), the amount of polypropylene resin used is 100 parts by weight, the amount of melamine-grafted POE elastomer used is 10-30 parts by weight, and the amount of phosphorylated polyvinyl alcohol used is 8-20 parts by weight.

[0013] Furthermore, the stirring temperature in (3) is 70-95° C. and the stirring time is 2-4 h.

[0014] Furthermore, the temperature of sections 1-6 of the twin-screw extruder in (3) is 160-200°C, and the screw speed is 50-100 r / min.

[0015] Furthermore, flame-retardant and high-toughness modified PP materials are used in network cables and wire sheath materials.

[0016] (3) Beneficial technical effects: The present invention melt-grafts 2,4-diamino-6-allylamino-1,3,5-triazine onto an ethylene-octene copolymer elastomer to obtain a melamine-grafted POE elastomer, which is then melt-blended and granulated with a polypropylene resin and phosphorylated polyvinyl alcohol to obtain a flame-retardant, high-toughness modified PP material. The POE elastomer has high toughness and good mechanical properties, and has a good toughening effect on polypropylene, which is beneficial to improving the impact strength and elongation at break of the material.

[0017] The POE elastomer of the present invention is grafted with a melamine structure, and the amino group of the melamine forms an ammonium phosphate structure with the phosphate group of the phosphated polyvinyl alcohol, thereby forming a chemical bond interaction between the POE elastomer and the polyvinyl alcohol. The POE elastomer has good compatibility with polypropylene, thereby improving the compatibility between the polyvinyl alcohol and the polypropylene and reducing the adverse effects of the polyvinyl alcohol on the toughness and mechanical properties of the polypropylene.

[0018] The POE elastomer of the present invention is grafted with a melamine structure as a gas source and phosphorylated polyvinyl alcohol as an acid source and a carbon source to form an intumescent flame retardant, thereby improving the flame retardancy of the polypropylene material and having a higher limiting oxygen index. The prepared PP material has good practical applications in the cross skeleton of Category 6 network cables, sheath materials for electric wires, and the like. DETAILED DESCRIPTION

[0019] The following will clearly and completely describe the concept and technical effects of this application in conjunction with the embodiments to fully understand the purpose, features and effects of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments of this application, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of this application.

[0020] Add 350 mL of water, 2.8 g of allylamine, 3.4 g of sodium bicarbonate, and 6 g of 2-chloro-4,6-diamino-1,3,5-triazine to 350 mL of ethanol, heat to 80°C, and reflux under condensation for 24 hours. After filtering, heat and evaporate the filtrate, and precipitate under ice bath to obtain 2,4-diamino-6-allylamino-1,3,5-triazine. The structural formula is

[0021] Example 1:

[0022] (1) Add 40 g of polyvinyl alcohol, 64 g of phosphoric acid, and 2 g of urea to 150 mL of water, heat to 50°C, stir for 8 h, then heat to 100°C, stir for 3 h, add ethanol, filter, wash with ethanol, purify, and dry to obtain phosphorylated polyvinyl alcohol.

[0023] (2) 200 g of ethylene-octene copolymer elastomer, 8 g of 2,4-diamino-6-allylamino-1,3,5-triazine, and 0.6 g of diisopropylbenzene peroxide were mixed and placed in a twin-screw extruder for grafting reaction. The temperatures of sections 1-6 were 160°C, 170°C, 175°C, 180°C, 180°C, and 180°C, and the screw speed was 80 r / min. The product was added to 6 L of xylene, heated to reflux, stirred, and then acetone was added for precipitation. The acetone was filtered, washed, purified, and then dried to obtain a melamine-grafted POE elastomer.

[0024] (3) Add 0.5 kg of melamine-grafted POE elastomer and 0.4 kg of phosphorylated polyvinyl alcohol to 4 L of water, heat to 90 ° C, stir for 2 h, dry and remove water, then add 5 kg of polypropylene resin and 13 g of antioxidant 1010 into a mixer and mix, then place it in a twin-screw extruder for melt extrusion, the temperatures of sections 1-6 are 160 ° C, 180 ° C, 195 ° C, 200 ° C, 200 ° C, 195 ° C, the screw speed is 100 r / min, and pelletizing is performed to obtain a flame retardant and high-toughness modified PP material.

[0025] Example 2:

[0026] (1) Add 40 g of polyvinyl alcohol, 96 g of phosphoric acid, and 4.4 g of urea to 180 mL of water, heat to 50°C, stir for 10 h, then heat to 90°C, stir for 5 h, add ethanol, filter, wash with ethanol, purify, and dry to obtain phosphorylated polyvinyl alcohol.

[0027] (2) 200 g of ethylene-octene copolymer elastomer, 15 g of 2,4-diamino-6-allylamino-1,3,5-triazine, and 1 g of diisopropylbenzene peroxide were mixed and placed in a twin-screw extruder for grafting reaction. The temperatures of sections 1-6 were 160°C, 170°C, 175°C, 180°C, 180°C, and 180°C, and the screw speed was 50 r / min. The product was added to 8 L of xylene, heated to reflux, stirred, and then acetone was added for precipitation. The acetone was filtered, washed, purified, and then dried to obtain a melamine-grafted POE elastomer.

[0028] (3) Add 1 kg of melamine-grafted POE elastomer and 0.7 kg of phosphorylated polyvinyl alcohol to 5 L of water, heat to 70 ° C, stir for 4 h, dry and remove water, then add 5 kg of polypropylene resin and 10 g of antioxidant 1010 into a mixer and mix, then place it in a twin-screw extruder for melt extrusion, the temperatures of sections 1-6 are 160 ° C, 180 ° C, 195 ° C, 200 ° C, 200 ° C, 195 ° C, the screw speed is 50 r / min, and pelletizing is performed to obtain a flame retardant and high-toughness modified PP material.

[0029] Example 3:

[0030] (1) Add 40 g of polyvinyl alcohol, 82 g of phosphoric acid, and 3.5 g of urea to 180 mL of water, heat to 60°C, stir for 7 h, then heat to 95°C, stir for 5 h, add ethanol, filter, wash with ethanol, purify, and dry to obtain phosphorylated polyvinyl alcohol.

[0031] (2) 200 g of ethylene-octene copolymer elastomer, 24 g of 2,4-diamino-6-allylamino-1,3,5-triazine, and 1.6 g of diisopropylbenzene peroxide were mixed and placed in a twin-screw extruder for grafting reaction. The temperatures of sections 1-6 were 160°C, 170°C, 175°C, 180°C, 180°C, and 180°C, and the screw speed was 50 r / min. The product was added to 8 L of xylene, heated to reflux, stirred, and then acetone was added for precipitation. The acetone was filtered, washed, purified, and then dried to obtain a melamine-grafted POE elastomer.

[0032] (3) Add 1.5 kg of melamine-grafted POE elastomer and 1 kg of phosphorylated polyvinyl alcohol to 6 L of water, heat to 95 ° C, stir for 3 h, dry and remove water, then add 5 kg of polypropylene resin and 15 g of antioxidant 1010 into a mixer and mix, then place it in a twin-screw extruder for melt extrusion, the temperatures of sections 1-6 are 160 ° C, 180 ° C, 195 ° C, 200 ° C, 200 ° C, 195 ° C, the screw speed is 80 r / min, and pelletizing is performed to obtain a flame retardant and high-toughness modified PP material.

[0033] Comparative Example 1: This comparative example differs from Example 1 in that 0.4 kg of phosphorylated polyvinyl alcohol is not added.

[0034] (1) Add 0.5 kg of melamine-grafted POE elastomer to 4 L of water, heat to 90 ° C, stir for 2 h, dry and remove water, then add 5 kg of polypropylene resin and 13 g of antioxidant 1010 into a mixer and mix, then place it in a twin-screw extruder for melt extrusion, the temperatures of sections 1-6 are 160 ° C, 180 ° C, 195 ° C, 200 ° C, 200 ° C, 195 ° C, the screw speed is 100 r / min, and pelletizing is performed to obtain a modified PP material.

[0035] Comparative Example 2: This comparative example differs from Example 1 in that polyvinyl alcohol is used instead of phosphorylated polyvinyl alcohol.

[0036] (1) Add 0.5 kg of melamine-grafted POE elastomer and 0.4 kg of polyvinyl alcohol to 4 L of water, heat to 90 ° C, stir for 2 h, dry and remove water, then add 5 kg of polypropylene resin and 13 g of antioxidant 1010 into a mixer and mix, then place it in a twin-screw extruder for melt extrusion, the temperatures of sections 1-6 are 160 ° C, 180 ° C, 195 ° C, 200 ° C, 200 ° C, 195 ° C, the screw speed is 100 r / min, and pelletizing is performed to obtain a modified PP material.

[0037] Comparative Example 3: This comparative example differs from Example 1 in that ethylene-octene copolymer elastomer is used instead of melamine-grafted POE elastomer.

[0038] (1) Add 0.5 kg of ethylene-octene copolymer elastomer and 0.4 kg of phosphorylated polyvinyl alcohol to 4 L of water, heat to 90 ° C, stir for 2 h, dry and remove water, then add 5 kg of polypropylene resin and 13 g of antioxidant 1010 into a mixer and mix, then place in a twin-screw extruder for melt extrusion, the 1-6 section temperatures are 160 ° C, 180 ° C, 195 ° C, 200 ° C, 200 ° C, 195 ° C, the screw speed is 100 r / min, and pelletizing is performed to obtain a modified PP material.

[0039] Comparative Example 4: The difference between this comparative example and Example 1 is that N-allylimidazole is used instead of 2,4-diamino-6-allylamino-1,3,5-triazine.

[0040] (1) 200 g of ethylene-octene copolymer elastomer, 8 g of N-allylimidazole, and 0.6 g of dicumyl peroxide were mixed and placed in a twin-screw extruder for grafting reaction. The temperatures of sections 1-6 were 160°C, 170°C, 175°C, 180°C, 180°C, and 180°C, and the screw speed was 80 r / min. The product was added to 6 L of xylene, heated to reflux, stirred, and then acetone was added for precipitation. The acetone was filtered, washed, purified, and then dried to obtain an imidazole-grafted POE elastomer.

[0041] (2) Add 0.5 kg of imidazole-grafted POE elastomer and 0.4 kg of phosphorylated polyvinyl alcohol to 4 L of water, heat to 90 ° C, stir for 2 h, dry and remove water, then add 5 kg of polypropylene resin and 13 g of antioxidant 1010 into a mixer and mix, then place it in a twin-screw extruder for melt extrusion, the temperatures of sections 1-6 are 160 ° C, 180 ° C, 195 ° C, 200 ° C, 200 ° C, 195 ° C, the screw speed is 100 r / min, and pelletizing is performed to obtain a modified PP material.

[0042] PP plastic was injection molded using an injection molding machine at three temperatures of 195°C, 210°C, and 210°C, and a pressure of 50 MPa to produce test strips. Impact strength was tested according to GB / T 1043.1-2008. Elongation at break was tested according to GB / T 1040.1-2018. Flammability was tested according to GB / T 2406.1-2008.

[0043] Table 1 Properties of PP materials

[0044]

[0045]

[0046] The PP materials of Examples 1 to 3 have high impact strength and elongation at break, good toughness, a large limiting oxygen index, and excellent flame retardant properties, mainly because melamine-grafted POE elastomers are added. The POE elastomer has a good toughening effect on polypropylene, which is beneficial to improving the impact strength and elongation at break of the material. The POE elastomer is grafted with a melamine structure, and its amino group forms an ammonium phosphate structure with the phosphate group of phosphorylated polyvinyl alcohol, thereby forming a chemical bond interaction between the POE elastomer and the polyvinyl alcohol, and the POE elastomer has good compatibility with polypropylene, thereby improving the compatibility between polyvinyl alcohol and polypropylene, reducing the adverse effects of polyvinyl alcohol on the toughness and mechanical properties of polypropylene, and maintaining good impact strength and elongation at break of polypropylene. At the same time, the POE elastomer is grafted with a melamine structure as a gas source, and phosphorylated polyvinyl alcohol is used as an acid source and a carbon source to form an intumescent flame retardant, which improves the flame retardant properties of polypropylene and has a higher limiting oxygen index.

[0047] In Comparative Example 1, phosphorylated polyvinyl alcohol was not added, and the limiting oxygen index of the PP material was very low, and the flame retardancy was very poor.

[0048] In Comparative Example 2, polyvinyl alcohol is used instead of phosphated polyvinyl alcohol. The melamine-grafted POE elastomer cannot form an ammonium phosphate chemical bond interaction with polyvinyl alcohol, and the compatibility between polyvinyl alcohol and polypropylene is not improved. Polyvinyl alcohol has a great influence on the toughness and mechanical properties of polypropylene, resulting in a decrease in impact strength and elongation at break. In addition, polyvinyl alcohol does not contain a phosphate group and cannot form an expanding flame retardant. The limiting oxygen index of the material is low and the flame retardancy is poor.

[0049] Comparative Example 3 uses ethylene-octene copolymer elastomer instead of melamine-grafted POE elastomer, which does not contain amino groups and cannot form ammonium phosphate chemical bond interaction with phosphated polyvinyl alcohol, and does not improve the compatibility between polyvinyl alcohol and polypropylene. Polyvinyl alcohol has a great influence on the toughness and mechanical properties of polypropylene, resulting in reduced impact strength and elongation at break. In addition, the POE elastomer does not contain a melamine structure and cannot form an expanding flame retardant. The limiting oxygen index of the material is low and the flame retardancy is poor.

[0050] In Comparative Example 4, N-allylimidazole was used to melt-graft an ethylene-octene copolymer elastomer. The obtained imidazole-grafted POE elastomer did not contain an amino group and could not form an ammonium phosphate chemical bond interaction with the phosphated polyvinyl alcohol. The compatibility between polyvinyl alcohol and polypropylene was not improved. Polyvinyl alcohol had a significant effect on the toughness and mechanical properties of polypropylene, resulting in reduced impact strength and elongation at break. In addition, the nitrogen content of the N-imidazole structure was lower than that of melamine, resulting in a lower nitrogen content in the intumescent flame retardant and a lower limiting oxygen index of the material than that in Example 1.

[0051] The present application has been described in detail above with reference to the embodiments. However, the present application is not limited to the above embodiments. Various modifications can be made within the scope of knowledge possessed by a person of ordinary skill in the art without departing from the purpose of the present application. In addition, the embodiments of the present application and the features of the embodiments can be combined with each other unless there is a conflict.

Claims

1. A method for preparing a flame retardant high-toughness modified PP material, characterized in that: The preparation method comprises: (1) mixing an ethylene-octene copolymer elastomer, 2,4-diamino-6-allylamino-1,3,5-triazine, and dicumyl peroxide, placing the mixture in a twin-screw extruder for grafting reaction, and obtaining a melamine-grafted POE elastomer after purification; (2) Add melamine-grafted POE elastomer and phosphorylated polyvinyl alcohol to water, stir and dry to remove water, then add them into a mixer with polypropylene resin and antioxidant to mix, then place them in a twin-screw extruder for melt extrusion and pelletize to obtain a flame-retardant and high-toughness modified PP material.

2. The method for preparing the flame retardant and high-toughness modified PP material according to claim 1, characterized in that: The amount of the ethylene-octene copolymer elastomer in (1) is 100 parts by weight, the amount of 2,4-diamino-6-allylamino-1,3,5-triazine is 4-12 parts by weight, and the amount of dicumyl peroxide is 0.3-0.8 parts by weight.

3. The method for preparing the flame retardant and high-toughness modified PP material according to claim 1, characterized in that: The temperature of sections 1-6 of the screw extruder in (1) is 160-180° C., and the screw speed is 50-80 r / min.

4. The method for preparing the flame retardant and high-toughness modified PP material according to claim 1, characterized in that: The amount of polypropylene resin in (2) is 100 parts by weight, the amount of melamine-grafted POE elastomer is 10-30 parts by weight, and the amount of phosphorylated polyvinyl alcohol is 8-20 parts by weight.

5. The method for preparing the flame retardant and high-toughness modified PP material according to claim 1, characterized in that: The stirring temperature in (2) is 70-95° C. and the stirring time is 2-4 h.

6. The method for preparing the flame retardant and high-toughness modified PP material according to claim 1, characterized in that: The temperature of sections 1-6 of the twin-screw extruder in (2) is 160-200° C., and the screw speed is 50-100 r / min.

7. The method for preparing the flame retardant and high-toughness modified PP material according to claim 1, characterized in that: The preparation method of the phosphorylated polyvinyl alcohol in (2) is as follows: adding 100 parts by weight of polyvinyl alcohol, 160-240 parts by weight of phosphoric acid, and 5-11 parts by weight of urea to water, heating to 50-60° C., stirring for 7-10 hours, then heating to 90-100° C., stirring for 3-5 hours, and purifying to obtain the phosphorylated polyvinyl alcohol.

8. A flame retardant and high-toughness modified PP material obtained by the preparation method according to any one of claims 1 to 7.

9. Use of the flame-retardant and high-toughness modified PP material according to claim 8 in network cables.

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