High-heat-resistance polypropylene and preparation method thereof

Abstract

The invention relates to high-heat-resistance polypropylene and a preparation method thereof, and belongs to the technical field of high polymer materials. The preparation method comprises the following steps: carrying out Michael addition reaction on 2-sulfydryl-1, 3-propylene glycol and vinyl dibutyl borate to prepare dihydric alcohol containing thioether and phosphate, and carrying out polymerization reaction on 1, 12-dodecanediol, boric acid ester dihydric alcohol and dimethyldichlorosilane to obtain the flame retardant. A polymer containing a borate group, a thioether group, organic silicon and a dodecane glycol ester group is prepared, the polymer is used as a heat-resistant toughening additive of polypropylene, the borate group and the organic silicon can improve the heat resistance and flame retardance of the polypropylene, and the thioether group and the dodecane glycol ester group can provide flexibility; therefore, the polypropylene is ensured to have good mechanical strength, heat resistance and flame retardance at the same time.

Description

Technical Field

[0001] This invention relates to a high heat-resistant polypropylene and its preparation method, belonging to the field of polymer materials technology. Background Technology

[0002] Polypropylene (PP) is a high-performance thermoplastic synthetic resin, a semi-transparent, lightweight, general-purpose plastic. It possesses excellent chemical resistance, heat resistance, electrical insulation, high mechanical strength, and good abrasion resistance, which has led to its rapid and widespread application in numerous fields such as machinery, automotive, electronics, construction, textiles, packaging, and food industries since its invention. Due to its plasticity, PP is gradually replacing wood products, and its high toughness and abrasion resistance are gradually replacing metal materials.

[0003] With the expanding applications of polypropylene, higher requirements are being placed on its heat resistance. Generally, the heat distortion temperature (HDT) is used to evaluate the heat resistance of polypropylene. The HDT refers to the temperature at which polypropylene begins to deform under a certain load. This temperature reflects the load-bearing capacity and stability of polypropylene under high-temperature conditions. In practical applications, if polypropylene products need to withstand high temperatures, materials with a high HDT must be selected to ensure product stability and safety. The HDT of polypropylene is affected by various factors, including the material's molecular structure, the type of additives, and the processing technology.

[0004] Currently, inorganic fillers (such as glass fiber) are generally used to improve the heat resistance of polypropylene, but this method will reduce the flexibility of polypropylene. Summary of the Invention

[0005] The purpose of this invention is to provide a high heat-resistant polypropylene and its preparation method, so as to solve the problem that the use of inorganic fillers to improve the heat resistance of polypropylene leads to a decrease in the flexibility of polypropylene.

[0006] This invention provides a high heat-resistant polypropylene, comprising polypropylene and a heat-resistant toughening additive; the preparation method of the heat-resistant toughening additive is as follows: (1) The mercapto group in 2-mercapto-1,3-propanediol and the vinyl group in dibutyl vinyl borate are subjected to Michael addition reaction to obtain borate diol; (2) 1,12-dodecanediol, borate diol and dimethyl dichlorosilane are polymerized in a solvent to obtain a heat-resistant toughening additive.

[0007] Preferably, the molar amount of chlorine in the dimethyldichlorosilane is equal to the sum of the molar amounts of hydroxyl groups in 1,12-dodecanediol and borate diol.

[0008] Preferably, triethylamine is added as an acid-binding agent during the polymerization reaction, and the molar amount of triethylamine is 1.2 to 1.5 times the molar amount of chlorine in dimethyldichlorosilane.

[0009] Preferably, the mass ratio of 1,12-dodecanediol to borate diol is 2~3:5~8.

[0010] Preferably, the polymerization reaction is carried out at a temperature of 45-50°C for 7-10 hours.

[0011] Preferably, the molar ratio of 2-mercapto-1,3-propanediol to dibutyl vinylborate is 1:1.

[0012] Preferably, the Michael addition reaction is catalyzed by triethylamine, and the mass of triethylamine is 3 to 5% of the mass of dibutyl vinylborate.

[0013] Preferably, the Michael addition reaction is carried out at a temperature of 50-60°C for 5-7 hours.

[0014] Preferably, the mass ratio of the polypropylene to the heat-resistant toughening additive is 55~60:15~20.

[0015] A method for preparing high heat-resistant polypropylene as described above includes the following steps: mixing polypropylene and heat-resistant toughening additives and then performing melt extrusion to obtain high heat-resistant polypropylene.

[0016] The beneficial effects of this invention are as follows: This invention prepares a diol containing thioethers and phosphate esters by Michael addition reaction of 2-mercapto-1,3-propanediol and dibutyl vinylborate. Then, 1,12-dodecanediol and borate diol are polymerized with dimethyl dichlorosilane to prepare a polymer containing borate groups, thioether groups, organosilicon and dodecanediol groups. This polymer is used as a heat-resistant and toughening additive for polypropylene. The borate groups and organosilicon can improve the heat resistance and flame retardancy of polypropylene, while the thioether groups and dodecanediol groups can provide flexibility, thereby ensuring that polypropylene has both good mechanical strength and heat resistance and flame retardancy. Detailed Implementation

[0017] The following examples are intended to further illustrate the content of the present invention, rather than to limit the scope of protection of the present invention.

[0018] The polypropylene raw materials used in the following examples and comparative examples are from the same batch of products from the same raw material supplier and have consistent performance. Example 1

[0019] The high heat-resistant polypropylene in this embodiment is composed of polypropylene and heat-resistant toughening additives in a mass ratio of 55:15; the preparation method of the heat-resistant toughening additives is as follows: (1) 2-Mercapto-1,3-propanediol and vinyl borate dibutyl ester in a molar ratio of 1:1 were added to a reaction vessel, and then anhydrous tetrahydrofuran and triethylamine were added (the mass of anhydrous tetrahydrofuran and triethylamine was 6 times and 3% of the mass of vinyl borate dibutyl ester, respectively). The mixture was heated to 50°C and stirred for 5 h. The mixture was then distilled under reduced pressure to remove tetrahydrofuran and triethylamine, and borate diol was obtained. (2) 1,12-dodecanediol, borate diol and dichloromethane in a mass ratio of 2:5:45 were added to a reaction vessel and cooled to 0°C. The material in the reaction vessel was stirred, and a dichloromethane solution of 8% dimethyldichlorosilane was added dropwise to the reaction vessel. After the addition was completed, triethylamine was added, and the mixture was heated to 45°C and stirred under reflux for 7 hours. The mixture was filtered, and the filtrate was distilled under reduced pressure to remove the solvent. After drying, the heat-resistant toughening additive was obtained. The molar amount of chlorine in dimethyldichlorosilane was equal to the sum of the molar amounts of hydroxyl groups in 1,12-dodecanediol and borate diol, and the molar amount of triethylamine was 1.2 times the molar amount of chlorine in dimethyldichlorosilane. Example 2

[0020] The high heat-resistant polypropylene in this embodiment is composed of polypropylene and heat-resistant toughening additives in a mass ratio of 58:17; the preparation method of the heat-resistant toughening additives is as follows: (1) 2-Mercapto-1,3-propanediol and vinyl borate dibutyl ester in a molar ratio of 1:1 were added to a reaction vessel, and then anhydrous tetrahydrofuran and triethylamine were added (the mass of anhydrous tetrahydrofuran and triethylamine was 6 times and 4% of the mass of vinyl borate dibutyl ester, respectively). The mixture was heated to 55°C and stirred for 6 hours. The mixture was then distilled under reduced pressure to remove tetrahydrofuran and triethylamine, and borate diol was obtained. (2) 1,12-dodecanediol, borate diol and dichloromethane in a mass ratio of 2:7:48 were added to a reaction vessel and cooled to 0°C. The material in the reaction vessel was stirred, and a 9% dimethyldichlorosilane solution in dichloromethane was added dropwise to the reaction vessel. After the addition was completed, triethylamine was added, and the mixture was heated to 48°C and stirred under reflux for 8 hours. The mixture was filtered, and the filtrate was distilled under reduced pressure to remove the solvent. After drying, the heat-resistant toughening additive was obtained. The molar amount of chlorine in dimethyldichlorosilane was equal to the sum of the molar amounts of hydroxyl groups in 1,12-dodecanediol and borate diol, and the molar amount of triethylamine was 1.3 times the molar amount of chlorine in dimethyldichlorosilane. Example 3

[0021] The high heat-resistant polypropylene in this embodiment is composed of polypropylene and heat-resistant toughening additives in a mass ratio of 60:20; the preparation method of the heat-resistant toughening additives is as follows: (1) 2-Mercapto-1,3-propanediol and vinyl borate dibutyl ester in a molar ratio of 1:1 were added to a reaction vessel, and then anhydrous tetrahydrofuran and triethylamine were added (the mass of anhydrous tetrahydrofuran and triethylamine was 7 times and 5% of the mass of vinyl borate dibutyl ester, respectively). The mixture was heated to 60°C and stirred for 7 h. The mixture was then distilled under reduced pressure to remove tetrahydrofuran and triethylamine, and borate diol was obtained. (2) 1,12-dodecanediol, borate diol and dichloromethane in a mass ratio of 3:8:50 were added to a reaction vessel and cooled to 0°C. The material in the reaction vessel was stirred, and a 10% dimethyldichlorosilane solution in dichloromethane was added dropwise to the reaction vessel. After the addition was completed, triethylamine was added, and the mixture was heated to 50°C and stirred under reflux for 10 hours. The mixture was filtered, and the filtrate was distilled under reduced pressure to remove the solvent. After drying, the heat-resistant toughening additive was obtained. The molar amount of chlorine in dimethyldichlorosilane was equal to the sum of the molar amounts of hydroxyl groups in 1,12-dodecanediol and borate diol, and the molar amount of triethylamine was 1.5 times the molar amount of chlorine in dimethyldichlorosilane.

[0022] Comparative Example 1 The high heat-resistant polypropylene in this comparative example is composed of polypropylene and heat-resistant toughening additives in a mass ratio of 55:15; the preparation method of the heat-resistant toughening additives is as follows: (1) 2-Mercapto-1,3-propanediol and vinyl borate dibutyl ester in a molar ratio of 1:1 were added to a reaction vessel, and then anhydrous tetrahydrofuran and triethylamine were added (the mass of anhydrous tetrahydrofuran and triethylamine was 6 times and 3% of the mass of vinyl borate dibutyl ester, respectively). The mixture was heated to 50°C and stirred for 5 h. The mixture was then distilled under reduced pressure to remove tetrahydrofuran and triethylamine, and borate diol was obtained. (2) 1,4-Butanediol, borate diol and dichloromethane in a mass ratio of 2:5:45 were added to a reaction vessel and cooled to 0°C. The material in the reaction vessel was stirred, and a dichloromethane solution of 8% dimethyldichlorosilane was added dropwise to the reaction vessel. After the addition was completed, triethylamine was added, and the mixture was heated to 45°C and stirred under reflux for 7 hours. The mixture was filtered, and the filtrate was distilled under reduced pressure to remove the solvent. After drying, the heat-resistant toughening additive was obtained. The molar amount of chlorine in dimethyldichlorosilane was equal to the sum of the molar amounts of hydroxyl groups in 1,4-Butanediol and borate diol, and the molar amount of triethylamine was 1.2 times the molar amount of chlorine in dimethyldichlorosilane.

[0023] Comparative Example 2 The high heat-resistant polypropylene in this comparative example is composed of polypropylene and heat-resistant toughening additives in a mass ratio of 55:15; the preparation method of the heat-resistant toughening additives is as follows: (1) 2-Mercapto-1,3-propanediol and vinyl borate dibutyl ester in a molar ratio of 1:1 were added to a reaction vessel, and then anhydrous tetrahydrofuran and triethylamine were added (the mass of anhydrous tetrahydrofuran and triethylamine was 6 times and 3% of the mass of vinyl borate dibutyl ester, respectively). The mixture was heated to 50°C and stirred for 5 h. The mixture was then distilled under reduced pressure to remove tetrahydrofuran and triethylamine, and borate diol was obtained. (2) 1,15-pentadecanediol, borate diol and dichloromethane in a mass ratio of 2:5:45 were added to a reaction vessel and cooled to 0°C. The material in the reaction vessel was stirred, and a dichloromethane solution of 8% dimethyldichlorosilane was added dropwise to the reaction vessel. After the addition was completed, triethylamine was added, and the mixture was heated to 45°C and stirred under reflux for 7 hours. The mixture was filtered, and the filtrate was distilled under reduced pressure to remove the solvent. After drying, the heat-resistant toughening additive was obtained. The molar amount of chlorine in dimethyldichlorosilane was equal to the sum of the molar amounts of hydroxyl groups in 1,15-pentadecanediol and borate diol, and the molar amount of triethylamine was 1.2 times the molar amount of chlorine in dimethyldichlorosilane.

[0024] Comparative Example 3 The high heat-resistant polypropylene in this comparative example is composed of polypropylene and heat-resistant toughening additives in a mass ratio of 55:15; the preparation method of the heat-resistant toughening additives is as follows: (1) 2-Mercapto-1,3-propanediol and vinyl borate dibutyl ester in a molar ratio of 1:1 were added to a reaction vessel, and then anhydrous tetrahydrofuran and triethylamine were added (the mass of anhydrous tetrahydrofuran and triethylamine was 6 times and 3% of the mass of vinyl borate dibutyl ester, respectively). The mixture was heated to 50°C and stirred for 5 h. The mixture was then distilled under reduced pressure to remove tetrahydrofuran and triethylamine, and borate diol was obtained. (2) 1,12-dodecanediol, borate diol and dichloromethane in a mass ratio of 4:8:45 were added to a reaction vessel and cooled to 0°C. The material in the reaction vessel was stirred, and a dichloromethane solution of 8% dimethyldichlorosilane was added dropwise to the reaction vessel. After the addition was completed, triethylamine was added, and the mixture was heated to 45°C and stirred under reflux for 7 hours. The mixture was filtered, and the filtrate was distilled under reduced pressure to remove the solvent. After drying, the heat-resistant toughening additive was obtained. The molar amount of chlorine in dimethyldichlorosilane was equal to the sum of the molar amounts of hydroxyl groups in 1,12-dodecanediol and borate diol, and the molar amount of triethylamine was 1.2 times the molar amount of chlorine in dimethyldichlorosilane.

[0025] Comparative Example 4 The high heat-resistant polypropylene in this comparative example is composed of polypropylene and heat-resistant toughening additives in a mass ratio of 55:15; the preparation method of the heat-resistant toughening additives is as follows: (1) 2-Mercapto-1,3-propanediol and vinyl borate dibutyl ester in a molar ratio of 1:1 were added to a reaction vessel, and then anhydrous tetrahydrofuran and triethylamine were added (the mass of anhydrous tetrahydrofuran and triethylamine was 6 times and 3% of the mass of vinyl borate dibutyl ester, respectively). The mixture was heated to 50°C and stirred for 5 h. The mixture was then distilled under reduced pressure to remove tetrahydrofuran and triethylamine, and borate diol was obtained. (2) 1,12-dodecanediol, borate diol and dichloromethane in a mass ratio of 1:5:45 were added to a reaction vessel and cooled to 0°C. The material in the reaction vessel was stirred, and a dichloromethane solution of 8% dimethyldichlorosilane was added dropwise to the reaction vessel. After the addition was completed, triethylamine was added, and the mixture was heated to 45°C and stirred under reflux for 7 hours. The mixture was filtered, and the filtrate was distilled under reduced pressure to remove the solvent. After drying, the heat-resistant toughening additive was obtained. The molar amount of chlorine in dimethyldichlorosilane was equal to the sum of the molar amounts of hydroxyl groups in 1,12-dodecanediol and borate diol, and the molar amount of triethylamine was 1.2 times the molar amount of chlorine in dimethyldichlorosilane.

[0026] Comparative Example 5 The high heat-resistant polypropylene in this comparative example is composed of polypropylene and heat-resistant toughening additives in a mass ratio of 55:15; the preparation method of the heat-resistant toughening additives is as follows: (1) 2-Mercapto-1,3-propanediol and vinyl borate dibutyl ester in a molar ratio of 1:1 were added to a reaction vessel, and then anhydrous tetrahydrofuran and triethylamine were added (the mass of anhydrous tetrahydrofuran and triethylamine was 6 times and 3% of the mass of vinyl borate dibutyl ester, respectively). The mixture was heated to 50°C and stirred for 5 h. The mixture was then distilled under reduced pressure to remove tetrahydrofuran and triethylamine, and borate diol was obtained. (2) 1,12-dodecanediol and dichloromethane in a mass ratio of 2:45 were added to a reaction vessel and cooled to 0°C. The material in the reaction vessel was stirred, and a dichloromethane solution of 8% dimethyldichlorosilane was added dropwise to the reaction vessel. After the addition was completed, triethylamine was added, and the mixture was heated to 45°C and stirred under reflux for 7 hours. The mixture was filtered, and the filtrate was distilled under reduced pressure to remove the solvent. After drying, additive A was obtained. The molar amount of chlorine in dimethyldichlorosilane was equal to the molar amount of hydroxyl in 1,12-dodecanediol, and the molar amount of triethylamine was 1.2 times the molar amount of chlorine in dimethyldichlorosilane. (3) Add borate diol and dichloromethane in a mass ratio of 5:45 to the reactor, cool to 0°C, and then stir the material in the reactor. At the same time, add a dichloromethane solution of 8% dimethyl dichlorosilane to the reactor dropwise. After the addition is complete, add triethylamine, then heat to 45°C, stir and reflux for 7 hours, filter, distill the filtrate under reduced pressure to remove the solvent, and dry to obtain additive B; wherein, the molar amount of chlorine in dimethyl dichlorosilane is equal to the molar amount of hydroxyl in borate diol, and the molar amount of triethylamine is 1.2 times the molar amount of chlorine in dimethyl dichlorosilane; (4) Stir additive A and additive B evenly to obtain heat-resistant toughening additive; the mass ratio of 1,12-dodecanediol in the preparation of additive A to the mass ratio of borate ester diol in the preparation of additive B is 2:5.

[0027] Experimental Example To examine the basic properties of the high heat-resistant polypropylene in each embodiment and comparative example, the high heat-resistant polypropylene in each embodiment and comparative example was stirred evenly according to the composition ratio and then melt-extruded at 200°C to obtain high heat-resistant polypropylene materials. Tensile strength was then tested according to the method in standard ISO 527, impact strength according to the method in standard ISO 179, and heat resistance and flame retardancy properties were tested according to the methods in standards ISO 306 and GB / T 2406. The test results of tensile strength, impact strength, and heat resistance and flame retardancy properties of the high heat-resistant polypropylene in each embodiment and comparative example are shown in Table 1.

[0028] Table 1 High heat-resistant polypropylene of each example and comparative example Tensile strength, impact strength and heat resistance and flame retardant performance test results

[0029] As shown in Table 1, the high heat-resistant polypropylene of the present invention exhibits good mechanical strength and heat-resistant flame retardancy. This is because the polypropylene of the present invention contains heat-resistant toughening additives, which contain borate ester groups, thioether groups, organosilicon groups, and dodecyl glycol ester groups. The borate ester groups and organosilicon groups can improve the crystallinity, heat resistance, and flame retardancy of polypropylene, while the thioether groups and dodecyl glycol ester groups can provide flexibility, thereby ensuring that the polypropylene simultaneously possesses good mechanical strength and heat-resistant flame retardancy.

[0030] As can be seen from Example 1 and Comparative Examples 1-2, after replacing the dodecanediol ester group with the butanediol ester group or the pentadecanediol ester group, the mechanical strength and heat resistance and flame retardancy of the material deteriorate. This indicates that the dodecanediol ester group can cooperate with the sulfide, borate ester group and organosilicon in the heat-resistant toughening additive to make the distribution density of the sulfide, borate ester group and organosilicon in the heat-resistant toughening additive more uniform and reasonable, thereby playing the role of toughening, improving crystallinity and heat resistance and flame retardancy.

[0031] As can be seen from Example 1 and Comparative Examples 3-4, by adjusting the mass ratio of 1,12-dodecanediol and borate diol, it was found that when the mass ratio is 2~3:5~8, it can better coordinate with dimethyldichlorosilane, improve the synergistic effect of dodecanediol ester, thioether, borate group and organosilicon, and thus exert the best reinforcing effect.

[0032] As can be seen from Example 1 and Comparative Example 5, when a mixture of polymers of dodecanediol and dimethyldichlorosilane and polymers of borate diol and dimethyldichlorosilane is used, although the system also contains dodecanediol ester, thioether, borate ester group and organosilicon structure, the dodecanediol ester is not in the same molecular chain as the thioether, borate ester group and organosilicon structure. The two are in a physical mixed state, and the synergistic effect is poor, which leads to the decline of material performance.

Claims

1. A high heat-resistant polypropylene, characterized in that, It includes polypropylene and a heat-resistant toughening additive; the preparation method of the heat-resistant toughening additive is as follows: (1) The mercapto group in 2-mercapto-1,3-propanediol and the vinyl group in dibutyl vinyl borate are subjected to Michael addition reaction to obtain borate diol; (2) 1,12-dodecanediol, borate diol and dimethyl dichlorosilane are polymerized in a solvent to obtain a heat-resistant toughening additive.

2. The high heat-resistant polypropylene as described in claim 1, characterized in that, The molar amount of chlorine in the dimethyldichlorosilane is equal to the sum of the molar amounts of hydroxyl groups in 1,12-dodecanediol and borate diol.

3. The high heat-resistant polypropylene as described in claim 1 or 2, characterized in that, Triethylamine is added as an acid-binding agent during the polymerization reaction, and the molar amount of triethylamine is 1.2 to 1.5 times the molar amount of chlorine in dimethyldichlorosilane.

4. The high heat-resistant polypropylene as described in claim 1 or 2, characterized in that, The mass ratio of the 1,12-dodecanediol to the borate diol is 2~3:5~8.

5. The high heat-resistant polypropylene as described in claim 1 or 2, characterized in that, The polymerization reaction is carried out at a temperature of 45-50°C for 7-10 hours.

6. The high heat-resistant polypropylene as described in claim 1, characterized in that, The molar ratio of 2-mercapto-1,3-propanediol to dibutyl vinylborate is 1:

1.

7. The high heat-resistant polypropylene as described in claim 1 or 6, characterized in that, The Michael addition reaction uses triethylamine as a catalyst, and the mass of triethylamine is 3 to 5% of the mass of dibutyl vinylborate.

8. The high heat-resistant polypropylene as described in claim 7, characterized in that, The Michael addition reaction is carried out at a temperature of 50-60°C for 5-7 hours.

9. The high heat-resistant polypropylene as described in claim 1, characterized in that, The mass ratio of the polypropylene to the heat-resistant toughening additive is 55~60:15~20.

10. A method for preparing high heat-resistant polypropylene as described in any one of claims 1-9, characterized in that, The process includes the following steps: mixing polypropylene and heat-resistant toughening additives and then performing melt extrusion to obtain high heat-resistant polypropylene.

Images