Preparation method of high-durability plastic

Abstract

The invention relates to a preparation method of high-durability plastic, and belongs to the technical field of high polymer materials. The high-durability plastic comprises the following components in parts by weight: 60-80 parts of polypropylene, 10-20 parts of glass fibers, 0.1-0.5 part of a lubricant, 0.1-5 parts of a modified flexibilizer, 0.5-3 parts of a modified flame retardant and 0.2-1 part of an antioxidant, a maleimide group in the modified toughening agent constructs an interpenetrating network structure, stress concentration of external force is relieved, the glass transition temperature and the melting point of the material are improved, and an oxazolidinone five-membered ring endows the material with high temperature resistance; piperazine derivatives and boron flame retardants in the modified flame retardants are compounded to construct an expanded carbon layer, nitrogen elements are converted into inert gas, oxygen and combustible gas are diluted, boron elements are combusted, heated and dehydrated, a B-O-C carbon layer is formed at a high temperature, flame-retardant gas is released, and the flame-retardant performance is improved; the high-durability plastic prepared by the invention not only has an excellent toughening effect, but also has good flame retardance and high temperature resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and in particular relates to a method for preparing highly durable plastics. Background Art

[0002] Polypropylene is a semi-crystalline thermoplastic. Due to its excellent mechanical properties, chemical corrosion resistance and thermal stability, it has shown broad application prospects in many fields such as food packaging, medical devices, and household items.

[0003] However, with the rapid development of global industrialization, the market demand for high-strength and durable plastics is growing. Traditional polypropylene plastics are prone to deformation and strength loss during use in high-temperature environments, which limits their application in high-temperature fields. In addition, polypropylene materials are derived from petrochemical materials and are composed of hydrocarbon elements. They are flammable and can easily be ignited to cause fires, posing safety hazards. These problems limit the wider and deeper application of polypropylene plastics. Therefore, the research and development of a high-durability plastic with excellent performance has important practical significance and application value. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a method for preparing a highly durable plastic.

[0005] The purpose of the present invention can be achieved through the following technical solutions: A highly durable plastic comprises the following raw materials in parts by weight: 60-80 parts of polypropylene, 10-20 parts of glass fiber, 0.1-0.5 parts of lubricant, 0.1-5 parts of modified toughening agent, 0.5-3 parts of modified flame retardant, and 0.2-1 parts of antioxidant; The lubricant is ethylene bis stearamide; The antioxidant is antioxidant 1098.

[0006] The modified toughening agent is prepared by the following method: Step A1: maleic anhydride is placed in a flask, sealed and introduced with ammonia gas, and when cooled to room temperature, the introduction of ammonia gas is stopped, and the temperature is raised to 180°C for reaction for 6 hours, and after cooling to room temperature, tetrahydrofuran, formaldehyde and sodium hydroxide are added and mixed evenly, and the mixture is reacted at 30°C for 4 hours, and the mixture is rotary evaporated, washed and centrifuged to obtain an intermediate; Further, the dosage ratio of maleic anhydride, tetrahydrofuran, formaldehyde, and sodium hydroxide is 0.33-0.65 g: 2.58-2.63 g: 0.1-0.2 g: 0.23-0.32 mL; First, maleic anhydride is imidized with ammonia, and then hydroxymethylated with formaldehyde to generate a hydroxyl-containing intermediate; Step A2: Mix the intermediate, tetrabutylammonium bromide and epichlorohydrin, sonicate for 1 h, and then add NaHCO 3 , stirred in an oil bath at 90°C for 12 h, filtered, rotary evaporated, washed, centrifuged, and dried at 45°C for 24 h to obtain the compound; Further, the intermediate, tetrabutylammonium bromide, epichlorohydrin, NaHCO 3 The dosage ratio is 0.1mol: 0.2-1mL: 9-9.2g: 0.2-0.5g; Secondly, the hydroxyl group of the intermediate is used to react with the epoxy group of epichlorohydrin, and then NaHCO 3 Treatment to epoxidize the epichlorohydrin terminal to generate a compound; Step A3: uniformly mix the compound, toluene diisocyanate and 2-ethyl-4-methylimidazole, heat the reaction system to 155-165° C., and stir the reaction for 2 hours to obtain a modified toughening agent; Further, the usage ratio of the compound, toluene diisocyanate, and 2-ethyl-4-methylimidazole is 0.01-0.02 mol: 1.25-2.5 g: 0.04-0.14 g; Finally, the epoxy group of the compound and the isocyanate group of toluene diisocyanate are added and polymerized to form an oxazolidinone group, thereby generating a modified toughening agent.

[0007] The modified flame retardant is prepared by the following method: Step B1: Add phenylboric acid and anhydrous piperazine to a three-necked flask equipped with a thermometer, a water separator and a reflux condenser, heat to 110°C for reaction for 1 hour, continue to heat to 150°C for reaction for 8 hours, evacuate for 0.5 hour, cool, add acetone, wash, filter and vacuum dry to obtain a piperazine derivative; Further, the dosage ratio of phenylboric acid, anhydrous piperazine, and acetone is 9.1-12.2 g: 5.4-7.2 g: 30-65 mL; Firstly, anhydrous piperazine is reacted with the hydroxyl group of phenylboronic acid to synthesize piperazine derivatives; Step B2: Mix the piperazine derivative and deionized water, stir magnetically in a constant temperature water bath at 90° C. for 1-2 hours, then add melamine, react for 3 hours, stop heating, naturally cool to room temperature under stirring, filter, wash, dry, and grind in a ball mill for 5 minutes, sieve with an 80-mesh sieve plate to obtain a modified flame retardant; Further, the usage ratio of piperazine derivative, deionized water and melamine is 0.05-0.1 mol: 100-200 mL: 4.2-8.4 g; Finally, the modified flame retardant was synthesized by utilizing the reaction between the hydroxyl group of the piperazine derivative and the amino group of melamine.

[0008] A method for preparing a highly durable plastic comprises the following steps: S1, mixing polypropylene and glass fiber to prepare a premixed material; S2, adding lubricant, modified toughening agent, modified flame retardant and antioxidant to the premixed material and mixing them evenly, stirring in a high-speed mixer for 5-10 minutes to obtain a mixed base material; S3. The mixed base material is placed in a twin-screw extruder at 200-240°C for extrusion granulation, the screw speed is controlled at 450-500r / min, and injection molding is performed by an injection molding machine to obtain a high-durability plastic.

[0009] Beneficial effects of the present invention: The high-durability plastic of the present invention not only has a good toughening effect and reduces brittleness, but also has excellent flame retardant and high temperature resistance properties, effectively extending the service life of the material.

[0010] The modified toughening agent prepared by the present invention, the maleimide group of the intermediate, due to its flexibility, enhances the flexibility of the polypropylene molecular chain, constructs an interpenetrating network structure, effectively alleviates the stress concentration under the action of external force, and thus improves the toughness and impact resistance of the material. At the same time, the maleimide group, due to its dipole moment perpendicular to the main axis of the molecular chain, enhances the intermolecular force, increases the glass transition temperature and melting point of the material, thereby increasing the rigidity and heat resistance of the molecular chain, preventing embrittlement at high temperature, and effectively prolonging the service life; in addition, the oxazolidinone five-membered ring structure, due to its high thermal decomposition temperature, large cohesive energy and strong carbon-oxygen double bond energy, gives the material excellent high temperature resistance, and comprehensively improves the comprehensive performance of the plastic.

[0011] The piperazine derivative in the modified flame retardant prepared by the present invention can effectively play the role of carbon source in polypropylene, and is compounded with a boron flame retardant to construct an expanded carbon layer, effectively isolate oxygen and fire sources, and produce a synergistic flame retardant effect; during combustion, the nitrogen element can be converted into an inert gas to dilute oxygen and combustible gas and reduce the combustion intensity. At the same time, the boron element is heated and dehydrated in the early stage of combustion, accelerating carbonization to form a glass-like protective layer to prevent the spread of combustion. The aromatic boric acid group contained in it forms a boron-oxygen network structure after heating, which is converted into a highly stable BOC carbon layer at high temperature, and releases non-combustible gas to play a foaming role, expand the carbon layer, form a heat-insulating and oxygen-isolating barrier, and significantly improve the flame retardant performance; in addition, the modified flame retardant prepared by the present invention is halogen-free, helps to reduce pollution to the environment and damage to the ecosystem, is harmless to human health, and achieves sustainable development. DETAILED DESCRIPTION

[0012] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0013] Embodiment 1: A method for preparing a highly durable plastic, comprising the following steps: S1. Weigh the raw materials by weight: 60 parts of polypropylene, 10 parts of glass fiber, 0.1 parts of lubricant, 0.1 parts of modified toughening agent (prepared in this embodiment), 0.5 parts of modified flame retardant (prepared in this embodiment), and 0.2 parts of antioxidant; mix the polypropylene and glass fiber to obtain a premixed material; S2, adding ethylene bisstearamide, modified toughening agent, modified flame retardant and antioxidant 1098 to the premixed material and mixing evenly, stirring in a high-speed mixer for 5 minutes to obtain a mixed base material; S3, placing the mixed base material in a twin-screw extruder at 200°C for extrusion and granulation, controlling the screw speed at 450r / min, and injection molding by an injection molding machine to obtain a highly durable plastic; The modified toughening agent is prepared by the following method: Step A1: 0.33 g of maleic anhydride was placed in a flask, and ammonia gas was introduced into the flask after the flask was sealed. When the flask was cooled to room temperature, the introduction of ammonia gas was stopped, and the temperature was raised to 180° C. for reaction for 6 h. After cooling to room temperature, 2.58 g of tetrahydrofuran, 0.1 g of formaldehyde and 0.23 mL of sodium hydroxide were added and mixed evenly, and the mixture was reacted at 30° C. for 4 h. The mixture was rotary evaporated, washed and centrifuged to obtain an intermediate; Step A2: Mix 0.1 mol of the intermediate, 0.2 mL of tetrabutylammonium bromide and 9 g of epichlorohydrin, sonicate for 1 h, and then add 0.2 g of NaHCO 3 , stirred in an oil bath at 90°C for 12 h, filtered, rotary evaporated, washed, centrifuged, and dried at 45°C for 24 h to obtain the compound; Step A3: 0.01 mol of the compound, 1.25 g of toluene diisocyanate and 0.04 g of 2-ethyl-4-methylimidazole were uniformly mixed, and the reaction system was heated to 155° C. and stirred for reaction for 2 hours to obtain a modified toughening agent; The modified flame retardant is prepared by the following method: Step B1: Add 9.1 g of phenylboric acid and 5.4 g of anhydrous piperazine to a three-necked flask equipped with a thermometer, a water separator and a reflux condenser, and heat to 110°C for reaction for 1 h. Continue to heat to 150°C for reaction for 8 h, evacuate for 0.5 h, cool, add 30 mL of acetone, wash, filter, and vacuum dry to obtain a piperazine derivative; Step B2: Mix 0.05 mol of piperazine derivative and 100 mL of deionized water, stir magnetically in a constant temperature water bath at 90°C for 1 hour, add 4.2 g of melamine, react for 3 hours, stop heating, cool naturally to room temperature while stirring, filter, wash, dry, and grind in a ball mill for 5 minutes. Sieve with an 80-mesh sieve to obtain a modified flame retardant.

[0014] Embodiment 2: A method for preparing a highly durable plastic, comprising the following steps: S1. Weigh the raw materials by weight: 70 parts of polypropylene, 15 parts of glass fiber, 0.3 parts of lubricant, 3 parts of modified toughening agent (prepared in this embodiment), 1.7 parts of modified flame retardant (prepared in this embodiment), and 0.6 parts of antioxidant; mix the polypropylene and glass fiber to obtain a premixed material; S2, adding ethylene bisstearic acid amide, modified toughening agent, modified flame retardant and antioxidant 1098 to the premixed material and mixing evenly, stirring in a high-speed mixer for 7 minutes to obtain a mixed base material; S3, placing the mixed base material in a twin-screw extruder at 220°C for extrusion and granulation, controlling the screw speed at 475r / min, and injection molding by an injection molding machine to obtain a highly durable plastic; The modified toughening agent is prepared by the following method: Step A1: 0.49 g of maleic anhydride was placed in a flask, and ammonia gas was introduced into the flask after the flask was sealed. When the flask was cooled to room temperature, the introduction of ammonia gas was stopped, and the temperature was raised to 180° C. for reaction for 6 h. After cooling to room temperature, 2.605 g of tetrahydrofuran, 0.15 g of formaldehyde and 0.275 mL of sodium hydroxide were added and mixed evenly, and the mixture was reacted at 30° C. for 4 h. The mixture was rotary evaporated, washed and centrifuged to obtain an intermediate; Step A2: Mix 0.1 mol of the intermediate, 0.6 mL of tetrabutylammonium bromide and 9.1 g of epichlorohydrin, sonicate for 1 h, and then add 0.35 g of NaHCO 3 , stirred in an oil bath at 90°C for 12 h, filtered, rotary evaporated, washed, centrifuged, and dried at 45°C for 24 h to obtain the compound; Step A3: 0.015 mol of the compound, 1.875 g of toluene diisocyanate and 0.09 g of 2-ethyl-4-methylimidazole were uniformly mixed, and the reaction system was heated to 160° C. and stirred for reaction for 2 h to obtain a modified toughening agent; The modified flame retardant is prepared by the following method: Step B1: Add 10.65 g of phenylboric acid and 6.3 g of anhydrous piperazine to a three-necked flask equipped with a thermometer, a water separator and a reflux condenser, heat to 110°C for reaction for 1 h, continue to heat to 150°C for reaction for 8 h, evacuate for 0.5 h, cool, add 48 mL of acetone, wash, filter and vacuum dry to obtain a piperazine derivative; Step B2: Mix 0.075 mol of piperazine derivative and 150 mL of deionized water, stir magnetically in a constant temperature water bath at 90°C for 1.5 h, add 6.3 g of melamine, react for 3 h, stop heating, cool naturally to room temperature while stirring, filter, wash, dry, and grind in a ball mill for 5 min. Sieve with an 80-mesh sieve to obtain a modified flame retardant.

[0015] Embodiment 3: A method for preparing a highly durable plastic, comprising the following steps: S1. Weigh the raw materials by weight: 80 parts of polypropylene, 20 parts of glass fiber, 0.5 parts of lubricant, 5 parts of modified toughening agent (prepared in this embodiment), 3 parts of modified flame retardant (prepared in this embodiment), and 1 part of antioxidant; mix the polypropylene and glass fiber to obtain a premixed material; S2, adding ethylene bisstearamide, modified toughening agent, modified flame retardant and antioxidant 1098 to the premixed material and mixing evenly, stirring in a high-speed mixer for 10 minutes to obtain a mixed base material; S3, placing the mixed base material in a twin-screw extruder at 240°C for extrusion and granulation, with the screw speed controlled at 500r / min, and injection molding by an injection molding machine to obtain a highly durable plastic; The modified toughening agent is prepared by the following method: Step A1: 0.65 g of maleic anhydride was placed in a flask, and ammonia gas was introduced into the flask after the flask was sealed. When the flask was cooled to room temperature, the introduction of ammonia gas was stopped, and the temperature was raised to 180° C. for reaction for 6 h. After cooling to room temperature, 2.63 g of tetrahydrofuran, 0.2 g of formaldehyde and 0.32 mL of sodium hydroxide were added and mixed evenly, and the mixture was reacted at 30° C. for 4 h. The mixture was rotary evaporated, washed and centrifuged to obtain an intermediate; Step A2: Mix 0.1 mol of the intermediate, 1 mL of tetrabutylammonium bromide and 9.2 g of epichlorohydrin, sonicate for 1 h, and then add 0.5 g of NaHCO 3 , stirred in an oil bath at 90°C for 12 h, filtered, rotary evaporated, washed, centrifuged, and dried at 45°C for 24 h to obtain the compound; Step A3: 0.02 mol of the compound, 2.5 g of toluene diisocyanate and 0.14 g of 2-ethyl-4-methylimidazole were uniformly mixed, and the reaction system was heated to 165° C. and stirred for 2 h to obtain a modified toughening agent; The modified flame retardant is prepared by the following method: Step B1: Add 12.2 g of phenylboric acid and 7.2 g of anhydrous piperazine to a three-necked flask equipped with a thermometer, a water separator and a reflux condenser, and heat to 110° C. for reaction for 1 h. Continue to heat to 150° C. for reaction for 8 h, evacuate for 0.5 h, cool, add 65 mL of acetone, wash, filter, and vacuum dry to obtain a piperazine derivative; Step B2: Mix 0.1 mol of piperazine derivative and 200 mL of deionized water, stir magnetically in a constant temperature water bath at 90°C for 2 h, add 8.4 g of melamine, react for 3 h, stop heating, cool naturally to room temperature while stirring, filter, wash, dry, and grind in a ball mill for 5 min. Sieve with an 80-mesh sieve to obtain a modified flame retardant.

[0016] Comparative Example 1: This comparative example is a highly durable plastic. The difference from Example 3 is that an equal amount of polybutadiene is used to replace the modified toughening agent prepared in Example 3, and the rest are the same.

[0017] Comparative Example 2: This comparative example is a highly durable plastic. The difference from Example 3 is that an equal amount of magnesium hydroxide is used to replace the modified flame retardant prepared in Example 3, and the rest is the same.

[0018] Performance test: The high-durability plastics prepared in Examples 1-3 and Comparative Examples 1-2 were cut into standard test sizes, and the tensile strength was tested according to GB / T1040.1-2006 (the tensile strength of polypropylene plastic is 33.05 MPa); the vertical burning performance was tested using the GB / T 2048-1996 plastic burning performance test method; the heat deformation temperature was tested according to the GB / T 1634.2-2004 standard, and the glass transition temperature was tested according to the standard GB / T 19466.2-2004; the test results are shown in Table 1 below: Table 1

[0019] It can be seen from the test data in Table 1 that the high-durability plastic prepared by the present invention has excellent toughening and flame retardant effects. It can also be seen from the above table that the high-durability plastic prepared by the present invention has good high temperature resistance.

[0020] The above contents are merely examples and explanations of the concept of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described 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 protection scope of the present invention.

Claims

1. A method for preparing a highly durable plastic, characterized in that: The specific steps include: S1. Weigh the raw materials by weight: 60-80 parts of polypropylene, 10-20 parts of glass fiber, 0.1-0.5 parts of lubricant, 0.1-5 parts of modified toughening agent, 0.5-3 parts of modified flame retardant, and 0.2-1 parts of antioxidant; mix the polypropylene and glass fiber to obtain a premixed material; S2, adding lubricant, modified toughening agent, modified flame retardant and antioxidant to the premixed material and mixing them evenly, stirring in a high-speed mixer for 5-10 minutes to obtain a mixed base material; S3, placing the mixed base material in a twin-screw extruder at 200-240°C for extrusion and granulation, controlling the screw speed at 450-500r / min, and injection molding by an injection molding machine to obtain a highly durable plastic; The modified toughening agent is prepared by the following method: Step A1: maleic anhydride is placed in a flask, sealed and introduced with ammonia gas, and when cooled to room temperature, the introduction of ammonia gas is stopped, and the temperature is raised to 180°C for reaction for 6 hours, and after cooling to room temperature, tetrahydrofuran, formaldehyde and sodium hydroxide are added and mixed evenly, and the mixture is reacted at 30°C for 4 hours, and the mixture is rotary evaporated, washed and centrifuged to obtain an intermediate; Step A2: The intermediate, tetrabutylammonium bromide and epichlorohydrin were mixed, and after ultrasonication for 1 hour, NaHCO3 was added, and the mixture was stirred in an oil bath at 90°C for 12 hours, and then filtered, rotary evaporated, washed, centrifuged, and dried at 45°C for 24 hours to obtain the compound; Step A3: uniformly mix the compound, toluene diisocyanate and 2-ethyl-4-methylimidazole, heat the reaction system to 155-165° C., and stir the reaction for 2 hours to obtain a modified toughening agent.

2. The method for preparing a highly durable plastic according to claim 1, characterized in that: In step A1, the usage ratio of maleic anhydride, tetrahydrofuran, formaldehyde and sodium hydroxide is 0.33-0.65 g: 2.58-2.63 g: 0.1-0.2 g: 0.23-0.32 mL.

3. The method for preparing a highly durable plastic according to claim 1, characterized in that: The usage ratio of the intermediate, tetrabutylammonium bromide, epichlorohydrin and NaHCO3 in step A2 is 0.1 mol: 0.2-1 mL: 9-9.2 g: 0.2-0.5 g.

4. The method for preparing a highly durable plastic according to claim 1, characterized in that: In step A3, the usage ratio of the compound, toluene diisocyanate and 2-ethyl-4-methylimidazole is 0.01-0.02 mol: 1.25-2.5 g: 0.04-0.14 g.

5. The method for preparing a highly durable plastic according to claim 1, characterized in that: The modified flame retardant is prepared by the following method: Step B1: Add phenylboric acid and anhydrous piperazine to a three-necked flask equipped with a thermometer, a water separator and a reflux condenser, heat to 110°C for reaction for 1 hour, continue to heat to 150°C for reaction for 8 hours, evacuate for 0.5 hour, cool, add acetone, wash, filter and vacuum dry to obtain a piperazine derivative; Step B2: Mix the piperazine derivative and deionized water, stir magnetically in a constant temperature water bath at 90°C for 1-2 hours, then add melamine, react for 3 hours, stop heating, cool naturally to room temperature while stirring, filter, wash, dry, and grind in a ball mill for 5 minutes, sieve with an 80-mesh sieve plate to obtain a modified flame retardant.

6. The method for preparing a highly durable plastic according to claim 5, characterized in that: In step B1, the usage ratio of phenylboric acid, anhydrous piperazine and acetone is 9.1-12.2 g: 5.4-7.2 g: 30-65 mL.

7. The method for preparing a highly durable plastic according to claim 5, characterized in that: In step B2, the usage ratio of piperazine derivative, deionized water and melamine is 0.05-0.1 mol: 100-200 mL: 4.2-8.4 g.

8. The method for preparing a highly durable plastic according to claim 1, characterized in that: The lubricant is ethylene bis stearic acid amide, and the antioxidant is antioxidant 1098.

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