Reinforced impact-resistant PP plastic and preparation method thereof
Through the synergistic effect of the modified β nucleating agent and the modified coordination elastomer, the number of β crystal forms and crystallization temperature are increased, and the problem of low impact resistance of polypropylene plastics is solved, achieving high impact strength and tensile resistance Performance improvement.
Patent Information
- Application Number
- CN202411574327.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-06
- Publication Date
- 2024-12-27
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
The existing polypropylene plastics have low impact resistance and are small in number of β crystal forms, making it difficult to have good tensile properties.
By preparing modified beta nucleating agents and modified coordination elastomers, the number of beta crystal forms and crystallization temperature are increased to form nanoscale dispersed beta nucleating polypropylene, and melt extrusion is enhanced in screw extruder. Impact resistant PP plastic.
The impact strength and tensile resistance of PP plastic are improved, stress is consumed through interlayer slip, cracks are prevented, and a tight network structure of covalent bonds and coordination bonds is introduced, which improves toughness and self-recovery.
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Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of polymer materials, and in particular relates to a reinforced impact-resistant PP plastic and a preparation method thereof. Background Art
[0002] Polypropylene is a thermoplastic resin obtained by addition polymerization of propylene monomer in the presence of a catalyst. It is widely used in the automotive industry, home appliances, electronics, packaging, building materials and other fields because of its low specific gravity, non-toxicity, easy processing, good flexibility and electrical insulation. It is one of the general-purpose plastics with a higher output.
[0003] At present, polypropylene mainly exists in three typical crystal forms: α, β, and γ. The most common is the α crystal form, which can be obtained by natural cooling during polypropylene processing. The α crystal form has a higher yield strength, but its impact resistance is lower. On the contrary, the β crystal form is a "bundle-like" structure formed by the growth of side-by-side bundled lamellae or a "spherical" structure formed by the collision of crystal bundles, and can dissipate stress through interlayer slip deformation. Therefore, its impact strength is higher, but the tensile strength is lower, and the number of β crystal forms is relatively small in the polypropylene molecule. Therefore, how to increase the number of β crystal forms in the polypropylene molecule to improve the impact resistance while also having good tensile properties is a technical problem that needs to be solved at present. Summary of the invention
[0004] The object of the present invention is to provide a reinforced impact-resistant PP plastic and a preparation method thereof to solve the problems in the background technology.
[0005] The purpose of the present invention can be achieved through the following technical solutions:
[0006] A reinforced impact-resistant PP plastic comprises the following raw materials in parts by weight:
[0007] 100-110 parts of β-nucleated polypropylene, 0.4-0.5 parts of plasticizer, 1.2-2.6 parts of modified coordination elastomer, 0.2-0.5 parts of dispersant, 0.8-1.2 parts of antioxidant;
[0008] The β-nucleated polypropylene is prepared by the following steps:
[0009] A1. Add trimesoyl chloride to cyclohexylamine in batches over 30 minutes under ice-water bath and stirring conditions. After the addition is completed, stir and react at 55-60°C for 4-5 hours. After cooling, place in excess concentrated hydrochloric acid and stir and mix. Finally, filter, wash and dry to obtain a modified β nucleating agent.
[0010] A2. Add modified β-nucleating agent to p-xylene, stir and mix, add pretreated polypropylene, mix evenly, reflux at 134° C. for 1-1.5 hours, cool, and then place in anhydrous ethanol for precipitation, and then filter, wash, and dry to obtain β-nucleated polypropylene;
[0011] Among them, cyclohexylamine and trimesoyl chloride are used as reaction monomers, the amino group and the acyl chloride are subjected to acylation reaction, and then concentrated hydrochloric acid is used for acidification precipitation to obtain an asymmetric aromatic amide modified β nucleating agent containing a carboxyl group; at the same time, the modified β nucleating agent is dispersed in the pretreated polypropylene base material at a nanometer scale, firstly, a flower-shaped β crystal nucleus is generated in the pretreated polypropylene matrix, and then β lamellae are attached to the outer edge of the β crystal nucleus to form β lamellae, and as the β lamellae gradually grow, the lamellae overlap with each other to finally form β nucleated polypropylene, thereby increasing the number of β crystals.
[0012] Furthermore, the usage ratio of cyclohexylamine and trimesoyl chloride is 22.97 mL: 26.5-28.3 g.
[0013] Furthermore, the concentration of the concentrated hydrochloric acid is 36wt%.
[0014] Furthermore, the dosage ratio of the p-xylene, the modified β-nucleating agent, the pretreated polypropylene and the anhydrous ethanol is 50 mL: 0.08-0.12 g: 10-15 g: 100 mL.
[0015] Further, the pretreated polypropylene is low-temperature plasma-treated polypropylene;
[0016] During the low-temperature plasma treatment, the atmosphere is air, the pressure is 18-22Pa, and the discharge power is 100-110W; the polypropylene bombarded with energy particles reacts with oxygen in the air, introducing oxygen-containing groups such as hydroxyl groups on its surface, thereby improving the surface activity of the pretreated polypropylene.
[0017] Furthermore, the modified coordinated elastomer is prepared by the following steps:
[0018] Adding 2-hydroxyethyl acrylate, hydroxyethyl methacrylate and methacrylic acid to anhydrous ethanol in sequence, stirring and mixing, then adding the polyacrylic acid metal complex solution, mixing evenly, adding urea and 2-hydroxy-2-methyl-1-phenyl-1-propanone, ultrasonically dispersing, then UV polymerization in a nitrogen atmosphere, and then distilling under reduced pressure and drying to obtain a modified coordination elastomer;
[0019] Among them, polyacrylic acid metal ligand is used as the coordination cross-linking network component, and the copolymer obtained by free radical polymerization of 2-hydroxyethyl acrylate, hydroxyethyl methacrylate and isomethacrylic acid is used as the covalent cross-linking network component and plays a supporting network role. Under the action of photoinitiator and urea catalyst, in-situ composite is carried out to obtain a modified coordination elastomer containing metal coordination cross-linking.
[0020] Furthermore, the usage ratio of anhydrous ethanol, 2-hydroxyethyl acrylate, hydroxyethyl methacrylate, methacrylic acid, polyacrylic acid metal complex solution, urea and 2-hydroxy-2-methyl-1-phenyl-1-propanone is 80mL: 2.5-2.8mL: 1.2-1.6mL: 0.7-1mL: 25mL: 0.1-0.7g: 0.2-0.8mL.
[0021] Furthermore, the polyacrylic acid metal complex solution is prepared by ultrasonically reacting magnesium nitrate hexahydrate and polyacrylic acid in deionized water at 30-40° C. for 20 minutes.
[0022] The dosage ratio of magnesium nitrate hexahydrate, polyacrylic acid and deionized water is 0.5-1.3 g: 6-8 mL: 30 mL; magnesium ions are complexed with carboxyl groups of polyacrylic acid in deionized water to obtain a polyacrylic acid metal complex solution coordinated with metal magnesium ions.
[0023] A method for preparing a reinforced impact-resistant PP plastic comprises the following steps:
[0024] Step S1: adding β-nucleated polypropylene, plasticizer, modified coordination elastomer, dispersant and antioxidant into a mixer and mixing them evenly to obtain a mixture;
[0025] Step S2: placing the mixed material in a screw extruder for melt extrusion, and then cooling, pelletizing and drying to obtain a reinforced impact-resistant PP plastic.
[0026] Beneficial effects of the present invention:
[0027] The modified β-nucleating agent of the present invention contains amide groups on its surface. When blended with pretreated polypropylene, it can be combined with the pretreated polypropylene through hydrogen bonds, thereby enhancing the compatibility and interface bonding force between the modified β-nucleating agent and the pretreated polypropylene. At the same time, the introduction of the modified β-nucleating agent promotes the increase in the number of β-nuclei in β-nucleated polypropylene molecules and reduces the energy required for nucleation, thereby effectively increasing the crystallization temperature and crystallization rate of the β-crystal form, increasing the number of β-crystal forms of the prepared PP plastic molecules, thereby improving the impact resistance of the PP plastic. When the plastic is impacted by an external force, due to the layered arrangement characteristics of the β-crystal form, stress can be consumed through interlayer slippage, effectively preventing the generation of cracks, thereby giving the PP plastic excellent impact resistance.
[0028] At the same time, the surface of the modified coordination elastomer of the present invention contains abundant ester groups, which, on the one hand, increases its compatibility and dispersibility in β-nucleated polypropylene, and on the other hand, can be firmly grafted to the surface of β-nucleated polypropylene through intermolecular forces, thereby introducing a tight network structure of double cross-linking of covalent bonds and coordination bonds on the surface of β-nucleated polypropylene, wherein the metal coordination bonds can not only disperse stress and avoid rupture due to local stress, but also improve the strength and self-healing property of the covalent cross-linked network. Under the synergistic effect of the two, the PP plastic is endowed with good toughness and tensile strength.
[0029] The invention uses polypropylene as a base material and introduces a modified β-nucleating agent and a modified coordinated elastomer with good compatibility to improve the impact strength and tensile strength of PP plastic. In addition, the modified coordinated elastomer can also play a role of heterogeneous nucleation, and is adsorbed in the gaps and grooves of β-nucleated polypropylene by coordination with metal magnesium ions, and promotes the orderly arrangement of molecular chains, thereby improving the nucleation efficiency. Under the synergistic effect of the two, the strength and impact resistance of PP plastic are further improved. DETAILED DESCRIPTION
[0030] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. 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.
[0031] Example 1
[0032] This embodiment provides β-nucleated polypropylene, which is prepared by the following steps:
[0033] A1. 10 g of polypropylene was subjected to low-temperature plasma treatment under the conditions of air atmosphere, pressure of 18 Pa, and discharge power of 100 W to obtain pretreated polypropylene;
[0034] A2. In an ice-water bath and under stirring conditions, a total amount of 26.5 g of trimesoyl chloride was added to 22.97 mL of cyclohexylamine in batches over a period of 30 min. After the addition was completed, the mixture was stirred and reacted at 55 ° C for 4 h. After cooling, the mixture was placed in an excess of 36 wt% concentrated hydrochloric acid and stirred and mixed. Finally, the mixture was filtered, washed, and dried to obtain a modified β nucleating agent.
[0035] A3. Add 0.08 g of modified β-nucleating agent to 50 mL of p-xylene, stir and mix, add 10 g of pretreated polypropylene, mix evenly, reflux at 134 °C for 1 h, cool, and then place in 100 mL of anhydrous ethanol for precipitation, and then filter, wash and dry to obtain β-nucleated polypropylene.
[0036] Example 2
[0037] This embodiment provides β-nucleated polypropylene, which is prepared by the following steps:
[0038] A1. 12 g of polypropylene was subjected to low-temperature plasma treatment under the conditions of air atmosphere, pressure of 20 Pa, and discharge power of 105 W to obtain pretreated polypropylene;
[0039] A2. In an ice-water bath and under stirring conditions, a total amount of 27.4 g of trimesoyl chloride was added to 22.97 mL of cyclohexylamine in batches over 30 min. After the addition was completed, the mixture was stirred and reacted at 58 ° C for 4.5 h. After cooling, the mixture was placed in an excess of 36 wt% concentrated hydrochloric acid and stirred and mixed. Finally, the mixture was filtered, washed, and dried to obtain a modified β nucleating agent.
[0040] A3. Add 0.1 g of modified β-nucleating agent to 50 mL of p-xylene, stir and mix, add 13 g of pretreated polypropylene, mix evenly, reflux at 134° C. for 1 h, cool, and then place in 100 mL of anhydrous ethanol for precipitation, and then filter, wash, and dry to obtain β-nucleated polypropylene.
[0041] Example 3
[0042] This embodiment provides β-nucleated polypropylene, which is prepared by the following steps:
[0043] A1. 15 g of polypropylene was subjected to low-temperature plasma treatment under the conditions of air atmosphere, pressure of 22 Pa, and discharge power of 110 W to obtain pretreated polypropylene;
[0044] A2. In an ice-water bath and under stirring conditions, a total amount of 28.3 g of trimesoyl chloride was added to 22.97 mL of cyclohexylamine in batches over a period of 30 min. After the addition was completed, the mixture was stirred and reacted at 60 ° C for 5 h. After cooling, the mixture was placed in an excess of 36 wt% concentrated hydrochloric acid and stirred and mixed. Finally, the mixture was filtered, washed, and dried to obtain a modified β nucleating agent.
[0045] A3. Add 0.12 g of modified β-nucleating agent to 50 mL of p-xylene, stir and mix, add 15 g of pretreated polypropylene, mix evenly, reflux at 134 °C for 1.5 h, cool, and then place in 100 mL of anhydrous ethanol for precipitation, and then filter, wash and dry to obtain β-nucleated polypropylene.
[0046] Example 4
[0047] This embodiment provides a modified coordinated elastomer, which is prepared by the following steps:
[0048] B1. Add 0.5 g of magnesium nitrate hexahydrate and 6 mL of polyacrylic acid to 30 mL of deionized water, and ultrasonically react for 20 min to obtain a polyacrylic acid metal complex solution;
[0049] B2. Add 2.5 mL of 2-hydroxyethyl acrylate, 1.2 mL of hydroxyethyl methacrylate and 0.7 mL of methacrylic acid to 80 mL of anhydrous ethanol in sequence, stir and mix, then add 25 mL of polyacrylic acid metal complex solution, mix evenly, add 0.1 g of urea and 0.2 mL of 2-hydroxy-2-methyl-1-phenyl-1-propanone, ultrasonically disperse, and then perform ultraviolet polymerization in a nitrogen atmosphere, and then perform reduced pressure distillation and drying to obtain a modified coordination elastomer.
[0050] Example 5
[0051] This embodiment provides a modified coordinated elastomer, which is prepared by the following steps:
[0052] B1. Add 0.8 g of magnesium nitrate hexahydrate and 7 mL of polyacrylic acid to 30 mL of deionized water, and react by ultrasonication for 20 min to obtain a polyacrylic acid metal complex solution;
[0053] B2. Add 2.6 mL of 2-hydroxyethyl acrylate, 1.4 mL of hydroxyethyl methacrylate and 0.9 mL of methacrylic acid to 80 mL of anhydrous ethanol in sequence, stir and mix, then add 25 mL of polyacrylic acid metal complex solution, mix evenly, add 0.4 g of urea and 0.5 mL of 2-hydroxy-2-methyl-1-phenyl-1-propanone, ultrasonically disperse, and then perform ultraviolet polymerization in a nitrogen atmosphere, and then perform reduced pressure distillation and drying to obtain a modified coordination elastomer.
[0054] Example 6
[0055] This embodiment provides a modified coordinated elastomer, which is prepared by the following steps:
[0056] B1. Add 1.3 g of magnesium nitrate hexahydrate and 8 mL of polyacrylic acid to 30 mL of deionized water, and react by ultrasonication for 20 min to obtain a polyacrylic acid metal complex solution;
[0057] B2. Add 2.8 mL of 2-hydroxyethyl acrylate, 1.6 mL of hydroxyethyl methacrylate and 1 mL of methacrylic acid to 80 mL of anhydrous ethanol in sequence, stir and mix, add 25 mL of polyacrylic acid metal complex solution, mix evenly, add 0.7 g of urea and 0.8 mL of 2-hydroxy-2-methyl-1-phenyl-1-propanone, ultrasonically disperse, and then perform ultraviolet polymerization in a nitrogen atmosphere, and then perform reduced pressure distillation and drying to obtain a modified coordination elastomer.
[0058] Example 7
[0059] This embodiment provides a method for preparing a reinforced impact-resistant PP plastic, comprising the following steps:
[0060] Step S1: adding 100 parts by weight of β-nucleated polypropylene, 0.4 parts by weight of a plasticizer, 1.2 parts by weight of a modified coordination elastomer, 0.2 parts by weight of a dispersant, and 0.8 parts by weight of an antioxidant into a mixer and mixing them uniformly to obtain a mixture;
[0061] Step S2: placing the mixed material in a screw extruder for melt extrusion, and then cooling, pelletizing and drying to obtain a reinforced impact-resistant PP plastic.
[0062] Example 8
[0063] This embodiment provides a method for preparing a reinforced impact-resistant PP plastic, comprising the following steps:
[0064] Step S1: adding 105 parts by weight of β-nucleated polypropylene, 0.45 parts by weight of a plasticizer, 2.1 parts by weight of a modified coordination elastomer, 0.3 parts by weight of a dispersant, and 0.95 parts by weight of an antioxidant into a mixer and mixing them uniformly to obtain a mixture;
[0065] Step S2: placing the mixed material in a screw extruder for melt extrusion, and then cooling, pelletizing and drying to obtain a reinforced impact-resistant PP plastic.
[0066] Example 9
[0067] This embodiment provides a method for preparing a reinforced impact-resistant PP plastic, comprising the following steps:
[0068] Step S1: adding 110 parts by weight of β-nucleated polypropylene, 0.5 parts by weight of a plasticizer, 2.6 parts by weight of a modified coordination elastomer, 0.5 parts by weight of a dispersant, and 1.2 parts by weight of an antioxidant into a mixer and mixing them uniformly to obtain a mixture;
[0069] Step S2: placing the mixed material in a screw extruder for melt extrusion, and then cooling, pelletizing and drying to obtain a reinforced impact-resistant PP plastic.
[0070] Comparative Example 1: Compared with Example 7, an equal amount of β-nucleated polypropylene was replaced by polypropylene, and the rest was the same.
[0071] Comparative Example 2: Compared with Example 7, an equal amount of β-nucleated polypropylene was replaced with a commercially available SBS elastomer, and the rest was the same.
[0072] Comparative Example 3: Compared with Example 7, no modified coordination elastomer is added, and the rest is the same.
[0073] Performance tests were performed on Examples 7 to 9 and Comparative Examples 1 to 3. Impact resistance: the samples were made into strips with a size of 80×10mm×2mm, and their impact strength was tested with reference to GB / T 1843-2008; tensile strength and elongation at break were tested with reference to GB / T1040.1-2018; β-crystal content: with reference to DB35 / T 1914-2020, the β-crystal content in the samples was tested by X-ray diffraction. The results are shown in Table 1:
[0074] Table 1
[0075]
[0076] It can be seen from Table 1 that the impact resistance and tensile strength of the PP plastics prepared from β-nucleated polypropylene and modified coordination elastomer in Examples 7-9 are higher than those in Comparative Examples 1-3, and the plastics have good impact resistance and toughness, and the elongation at break can reach up to 730.9%. In addition, compared with Comparative Examples 1 and 3, the examples have a higher β-crystal content, indicating that under the synergistic effect of the β-polypropylene prepared from the modified β-nucleating agent and the modified coordination elastomer, the PP plastic has a higher β-crystal content and a higher impact strength.
[0077] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.
[0078] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.
Claims
1. A reinforced impact-resistant PP plastic, characterized in that: Including the following ingredients: 100-110 parts of β-nucleated polypropylene, 0.4-0.5 parts of plasticizer, 1.2-2.6 parts of modified coordination elastomer, 0.2-0.5 parts of dispersant, 0.8-1.2 parts of antioxidant; The β-nucleated polypropylene is prepared by the following steps: A1. Add trimesoyl chloride to cyclohexylamine in batches over 30 minutes under ice-water bath and stirring conditions. After the addition is completed, stir and react at 55-60°C for 4-5 hours. After cooling, place in excess concentrated hydrochloric acid and stir and mix. Finally, filter, wash and dry to obtain a modified β nucleating agent. A2. Add modified β-nucleating agent to p-xylene, stir and mix, add pretreated polypropylene, mix evenly, reflux at 134°C for 1-1.5h, cool, and then place in anhydrous ethanol for precipitation, and then filter, wash and dry to obtain β-nucleated polypropylene.
2. The reinforced impact-resistant PP plastic according to claim 1, characterized in that: The usage ratio of cyclohexylamine and trimesoyl chloride is 22.97 mL: 26.5-28.3 g.
3. The reinforced impact-resistant PP plastic according to claim 1, characterized in that: The concentration of the concentrated hydrochloric acid is 36 wt %.
4. The reinforced impact-resistant PP plastic according to claim 1, characterized in that: The dosage ratio of the p-xylene, the modified beta nucleating agent, the pretreated polypropylene and the anhydrous ethanol is 50 mL: 0.08-0.12 g: 10-15 g: 100 mL.
5. The reinforced impact-resistant PP plastic according to claim 1, characterized in that: The pretreated polypropylene is polypropylene treated with low-temperature plasma.
6. The reinforced impact-resistant PP plastic according to claim 1, characterized in that: The modified coordinated elastomer is prepared by the following steps: Add 2-hydroxyethyl acrylate, hydroxyethyl methacrylate and methacrylic acid to anhydrous ethanol in sequence, stir and mix, then add polyacrylic acid metal complex solution, mix evenly, add urea and 2-hydroxy-2-methyl-1-phenyl-1-propanone, ultrasonically disperse, perform ultraviolet polymerization in a nitrogen atmosphere, and then perform reduced pressure distillation and drying to obtain a modified coordination elastomer.
7. The reinforced impact-resistant PP plastic according to claim 6, characterized in that: The dosage ratio of anhydrous ethanol, 2-hydroxyethyl acrylate, hydroxyethyl methacrylate, methacrylic acid, polyacrylic acid metal complex solution, urea and 2-hydroxy-2-methyl-1-phenyl-1-propanone is 80 mL: 2.5-2.8 mL: 1.2-1.6 mL: 0.7-1 mL: 25 mL: 0.1-0.7 g: 0.2-0.8 mL.
8. The reinforced impact-resistant PP plastic according to claim 6, characterized in that: The polyacrylic acid metal complex solution is prepared by reacting magnesium nitrate hexahydrate and polyacrylic acid in deionized water at 30-40° C. for 20 minutes through ultrasonic reaction.
9. The reinforced impact-resistant PP plastic according to claim 8, characterized in that: The dosage ratio of magnesium nitrate hexahydrate, polyacrylic acid and deionized water is 0.5-1.3 g: 6-8 mL: 30 mL.
10. The method for preparing a reinforced impact-resistant PP plastic according to claim 1, characterized in that: The following steps are involved: Step S1: adding β-nucleated polypropylene, plasticizer, modified coordination elastomer, dispersant and antioxidant into a mixer and mixing them evenly to obtain a mixture; Step S2: placing the mixed material in a screw extruder for melt extrusion, and then cooling, pelletizing and drying to obtain a reinforced impact-resistant PP plastic.