Polypropylene material as well as preparation method and application thereof

Abstract

The invention provides a polypropylene material as well as a preparation method and application thereof, and the polypropylene material is prepared from the following components in parts by weight: 96.2 to 99.63 parts of polypropylene resin, 0.1 to 2 parts of silane coupling agent modified nano silicon dioxide and 0.07 to 1.4 parts of dispersing aid. When the MFR of the polypropylene resin is greater than or equal to 5g / 10min and less than 20g / 10min, the particle size of the modified nano silicon dioxide is 10-20nm, and when the MFR of the polypropylene resin is greater than or equal to 20g / 10min and less than or equal to 40g / 10min, the size of the modified nano silicon dioxide is 5-10nm. The modified nano silicon dioxide is uniformly dispersed into a polypropylene matrix, so that the viscosity is greatly reduced while the toughness of the polypropylene resin is maintained.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer materials, and particularly relates to a polypropylene material, a preparation method thereof, and an application thereof. Background Art

[0002] As a general-purpose plastic, polypropylene has a simple synthesis process, stable performance, and low price. Since its industrialization in the 1950s, the application of polypropylene has developed rapidly and has become the most widely used resin material at present. High-flow and high-impact copolymer polypropylene is widely used in the injection molding of large thin-walled products, such as household appliance products, automotive parts, industrial parts, etc., due to its easy processing, modification, and excellent impact performance. However, due to the difficult production of high-flow impact-resistant polypropylene and the imbalance and difficulty in controlling its comprehensive performance, there is a large domestic production gap at present, and a large amount of high-priced raw materials still need to be imported from abroad every year for production.

[0003] Currently, regarding high-flow impact-resistant polypropylene, the industry often prepares it by regulating the molecular weight of the polypropylene phase and the rubber phase content at the synthesis end, or by post-modification methods. CN115521544A discloses a method for adjusting hydrogen, catalyst, and equipment parameters in the polymerization section, and successfully synthesizes high-impact copolymer polypropylene with a melt flow rate > 15 g / 10 min and a notched Izod impact strength ≥ 50 kJ / m 2 However, in the currently existing preparation methods of high-flow impact-resistant polypropylene, the adjustability of product fluidity and toughness at the synthesis end is limited, and it is difficult to achieve high impact in products with a melt flow rate > 30 g / 10 min. The post-modification method requires a large amount of toughening agent to be added, resulting in a relatively large increase in the comprehensive cost.

[0004] Therefore, there is a need in the art to develop a method for reducing the viscosity of high-impact copolymer polypropylene at low cost while maintaining the mechanical properties of the material. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a polypropylene material, a preparation method thereof, and an application thereof.

[0006] To achieve the purpose of this invention, the following technical solutions are adopted:

[0007] In the first aspect, the present invention provides a polypropylene material, which comprises the following components in parts by weight:

[0008] Polypropylene resin 96.2 - 99.63 parts;

[0009] Silane coupling agent-modified nano-silica 0.1 - 2 parts;

[0010] Dispersing agent: 0.07 - 1.4 parts;

[0011] The weight parts of the polypropylene resin can be 96.2 parts, 96.4 parts, 96.8 parts, 97 parts, 97.2 parts, 97.4 parts, 97.6 parts, 97.8 parts, 98 parts, 98.2 parts, 98.4 parts, 98.6 parts, 98.8 parts, 99 parts, 99.2 parts, 99.4 parts, 99.6 parts, 99.63 parts, etc.

[0012] The weight parts of the modified nano - silica can be 0.1 part, 0.3 part, 0.5 part, 0.7 part, 0.9 part, 1.1 parts, 1.3 parts, 1.5 parts, 1.7 parts, 1.9 parts, 2 parts, etc.

[0013] The weight parts of the dispersing agent can be 0.07 part, 0.09 part, 0.1 part, 0.3 part, 0.5 part, 0.7 part, 0.9 part, 1 part, 1.1 parts, 1.2 parts, 1.3 parts, 1.4 parts, etc.

[0014] The melt flow rate MFR of the polypropylene resin at 230°C and 2.16 kg is 5 - 40 g / 10 min.

[0015] When the MFR of the polypropylene resin satisfies 5 g / 10 min ≤ MFR < 20 g / 10 min (such as 5 g / 10 min, 6 g / 10 min, 7 g / 10 min, 8 g / 10 min, 9 g / 10 min, 10 g / 10 min, 11 g / 10 min, 12 g / 10 min, 13 g / 10 min, 14 g / 10 min, 15 g / 10 min, 16 g / 10 min, 17 g / 10 min, 18 g / 10 min, 19 g / 10 min, etc.), the particle size of the modified nano - silica is 10 - 20 nm (such as 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, 16 nm, 17 nm, 18 nm, 19 nm, 20 nm, etc.).

[0016] When the MFR of the polypropylene resin satisfies 20 g / 10 min ≤ MFR ≤ 40 g / 10 min (such as 20 g / 10 min, 21 g / 10 min, 22 g / 10 min, 23 g / 10 min, 24 g / 10 min, 25 g / 10 min, 26 g / 10 min, 27 g / 10 min, 28 g / 10 min, 29 g / 10 min, 30 g / 10 min, 31 g / 10 min, 32 g / 10 min, 33 g / 10 min, 34 g / 10 min, 35 g / 10 min, 36 g / 10 min, 37 g / 10 min, 38 g / 10 min, 39 g / 10 min, 40 g / 10 min, etc.), the particle size of the modified nano-silica is 5-10 nm (such as 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, etc.).

[0017] Any other specific point values within the above numerical range can be selected and will not be elaborated one by one here.

[0018] The polypropylene material involved in the present invention creatively disperses the modified nano-silica uniformly into the polypropylene matrix and introduces it into the entanglement network of molecular chains. Through the selective diffusion effect, it promotes the disentanglement of polypropylene molecular chains, so that while maintaining the toughness of the polypropylene resin, the viscosity is significantly reduced. At the same time, the present invention also creatively selects modified nano-silica particles of different sizes according to the melt flow rate of the polypropylene resin, further improving the flowability and impact resistance of the polypropylene material.

[0019] According to molecular dynamics calculations, nano-particles with a size smaller than the root mean square radius of gyration of the polymer have excellent compatibility with the polymer, and can achieve uniform dispersion at the molecular chain level after appropriate dispersion processes. The nano-silica particles selected in the present invention, after surface modification, have a particle size smaller than or close to the root mean square radius of gyration of the selected polypropylene, so they can diffuse rapidly within the polypropylene chain. Since the surface of the nano-particles is rigid, their diffusion effect will prevent the entanglement of polymer chains and reduce the degree of polymer entanglement, thereby macroscopically reducing the polymer viscosity. The main toughness of the copolymerized polypropylene comes from the EPR phase, and the nano-particles mainly aggregate in the PP phase of the polymer matrix and will not damage the structure of the EPR phase, so the product toughness can be maintained at a high level.

[0020] In addition, the raw materials used in the present invention are easy to obtain, inexpensive, with a low additive amount of auxiliaries, and have no toxic effects on the human body, being safe, inexpensive and highly universal. The polypropylene material involved in the present invention can further reduce the viscosity of polypropylene and increase the upper limit of the melt index of the product on the basis of the existing synthesis of high-flow and high-impact polypropylene in the petrochemical industry.

[0021] Preferably, the polypropylene resin is a copolymerized polypropylene, such as a block copolymerized polypropylene.

[0022] It should be noted that based on the mass percentage content of the polypropylene material being 100%, the mass percentage content of the polypropylene resin is 96.2% - 99.63%, such as 96.4%, 96.8%, 97%, 97.4%, 97.8%, 98%, 98.4%, 98.8%, 99%, 99.2%, 99.4%, 99.63%, etc.

[0023] Based on the mass percentage content of the polypropylene material being 100%, the mass percentage content of the modified nano-silica is 0.1% - 2%, such as 0.1%, 0.3%, 0.5%, 0.7%, 0.9%, 1.1%, 1.3%, 1.5%, 1.7%, 1.9%, 2%, etc.

[0024] Based on the mass percentage content of the polypropylene material being 100%, the mass percentage content of the dispersion aid is 0.07%, 0.09%, 0.1%, 0.3%, 0.5%, 0.7%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, etc.

[0025] Any other specific point values within the above numerical range can be selected, and will not be elaborated one by one here.

[0026] In the present invention, a coupling agent is used to modify the surface of nano-silica, effectively reducing its self-aggregation and improving its dispersion uniformity in the polypropylene resin.

[0027] Preferably, the silane coupling agent includes any one or a combination of at least two of a silane coupling agent containing an unsaturated double bond, an aminopropyl silane coupling agent, or a mercaptopropyl silane coupling agent, and is further preferably a silane coupling agent containing an unsaturated double bond.

[0028] Preferably, the silane coupling agent containing an unsaturated double bond includes any one or a combination of at least two of vinyltrimethoxysilane, vinyltriethoxysilane, or γ-methacryloyloxypropyltrimethoxysilane.

[0029] Those skilled in the art can conventionally select the method for modifying silica with a silane coupling agent, such as first preparing a solution of the silane coupling agent and then mixing it with silica by spraying or soaking, or directly mixing the silane coupling agent with silica. The purpose of using the silane coupling agent to modify silica is to uniformly coat the silane coupling agent on the surface of silica, and the specific use method of the silane coupling agent in this case is not specifically limited.

[0030] In one embodiment, the modified nano-silica is prepared by a method including the following steps:

[0031] Mix the silane coupling agent solution with the nano-silica dispersion and then react to obtain the modified nano-silica.

[0032] Preferably, the mass ratio of the silane coupling agent to the silica is 1:(15 - 25), such as 1:15, 1:16, 1:17, 1:18, 1:19, 1:20, 1:21, 1:22, 1:23, 1:24, 1:25, etc. Any other specific point value within this numerical range can be selected and will not be elaborated one by one here.

[0033] Preferably, the silane coupling agent solution is obtained by mixing the silane coupling agent with an ethanol aqueous solution, adjusting the pH to 3.5 - 4.5 (such as 3.5, 3.6, 3.7, 3.8, 3.9, 4, 4.1, 4.2, 4.3, 4.4, 4.5, etc.), and standing for hydrolysis at 35 - 45°C (such as 35°C, 36°C, 37°C, 38°C, 39°C, 40°C, 41°C, 42°C, 43°C, 44°C, 45°C, etc.) for 40 - 80 min (such as 40 min, 45 min, 50 min, 55 min, 60 min, 65 min, 70 min, 75 min, 80 min, etc.). Any other specific point value within this numerical range can be selected and will not be elaborated one by one here.

[0034] Preferably, the silica dispersion is obtained by mixing the dried silica with an ethanol aqueous solution and ultrasonically dispersing it at 35 - 45°C (such as 35°C, 36°C, 37°C, 38°C, 39°C, 40°C, 41°C, 42°C, 43°C, 44°C, 45°C, etc.) for 40 - 80 min (such as 40 min, 45 min, 50 min, 55 min, 60 min, 65 min, 70 min, 75 min, 80 min, etc.). Any other specific point value within this numerical range can be selected and will not be elaborated one by one here.

[0035] Preferably, both the mixing and the reaction are carried out under heating and stirring at 65 - 75°C (such as 65°C, 66°C, 67°C, 68°C, 69°C, 70°C, 71°C, 72°C, 73°C, 74°C, 75°C, etc.). Any other specific point value within this numerical range can be selected and will not be elaborated one by one here.

[0036] Preferably, the reaction time is 3 - 5 h (such as 3 h, 3.2 h, 3.4 h, 3.6 h, 3.8 h, 4 h, 4.2 h, 4.4 h, 4.6 h, 4.8 h, 5 h, etc.). Any other specific point value within this numerical range can be selected and will not be elaborated one by one here.

[0037] Preferably, centrifugation and drying are also carried out after the reaction.

[0038] Preferably, the centrifugation includes taking the supernatant in the first centrifugation, taking the supernatant in the second centrifugation, and then taking the precipitate in the third centrifugation.

[0039] Preferably, the rotation speed of the first centrifugation is 4000 - 6000 r / min (such as 4000 r / min, 4500 r / min, 5000 r / min, 5500 r / min, 6000 r / min, etc.), and the time is 6 - 10 min (such as 6 min, 7 min, 8 min, 9 min, 10 min, etc.). Any other specific point values within the above numerical range can be selected and will not be elaborated one by one here.

[0040] Preferably, the rotation speed of the second centrifugation is 6000 - 10000 r / min (such as 6000 r / min, 7000 r / min, 7500 r / min, 8000 r / min, 8500 r / min, 9000 r / min, 9500 r / min, 10000 r / min, etc.), and the time is 6 - 10 min (such as 6 min, 7 min, 8 min, 9 min, 10 min, etc.). Any other specific point values within the above numerical range can be selected and will not be elaborated one by one here.

[0041] Preferably, the rotation speed of the third centrifugation is 13000 - 17000 r / min (such as 13000 r / min, 13500 r / min, 14000 r / min, 14500 r / min, 15000 r / min, 15500 r / min, 16000 r / min, 16500 r / min, 17000 r / min, etc.), and the time is 6 - 10 min (such as 6 min, 7 min, 8 min, 9 min, 10 min, etc.). Any other specific point values within the above numerical range can be selected and will not be elaborated one by one here.

[0042] Preferably, the dispersion aid includes any one or a combination of at least two of white oil, sodium stearate, or silicone.

[0043] Preferably, the dispersion aid is a combination of white oil and sodium stearate.

[0044] Preferably, the mass ratio of white oil to sodium stearate is (1 - 3):1, such as 1:1, 1.2:1, 1.4:1, 1.6:1, 1.8:1, 2:1, 2.2:1, 2.4:1, 2.6:1, 2.8:1, 3:1, etc. Any other specific point values within this numerical range can be selected and will not be elaborated one by one here.

[0045] The present invention creatively discovers that when choosing the combination of white oil and sodium stearate as the dispersion aid, it can better assist the dispersion of nano-silica and further reduce the viscosity of polypropylene resin. Due to the extremely small particle size, high surface energy of nano-silica, and being a solid particle that cannot be melted, it is prone to agglomeration in the internal mixer. White oil and sodium stearate have low melting points and good compatibility with polypropylene. Before melting, they adhere to the surface of polypropylene to form a coating layer to prevent powder adhesion, and after melting, they serve as infiltration channels to promote the uniform mixing of nano-silica into the entanglement network of polypropylene molecular chains.

[0046] Preferably, the polypropylene material further comprises 0.1 - 0.2 parts (such as 0.1 part, 0.11 part, 0.12 part, 0.13 part, 0.14 part, 0.15 part, 0.16 part, 0.17 part, 0.18 part, 0.19 part, 0.2 part, etc.) of a primary antioxidant in terms of parts by weight. Any other specific point value within this numerical range can be selected, and they will not be elaborated one by one here.

[0047] Preferably, the primary antioxidant includes a hindered phenol antioxidant and / or a hydroxylamine antioxidant.

[0048] Preferably, the hindered phenol antioxidant includes any one or a combination of at least two of pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate, octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, ethylene bis(oxyethylene) bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate], or 3,9-bis[1,1-dimethyl-2-[(3-tert-butyl-4-hydroxy-5-methylphenyl)propanoyloxy]ethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane.

[0049] Preferably, the hydroxylamine antioxidant includes bis(octadecyl)hydroxylamine.

[0050] Preferably, the polypropylene material further comprises 0.1 - 0.2 parts (such as 0.1 part, 0.11 part, 0.12 part, 0.13 part, 0.14 part, 0.15 part, 0.16 part, 0.17 part, 0.18 part, 0.19 part, 0.2 part, etc.) of a secondary antioxidant in terms of parts by weight. Any other specific point value within this numerical range can be selected, and they will not be elaborated one by one here.

[0051] Preferably, the secondary antioxidant includes any one or a combination of at least two of phosphite antioxidants, phosphate antioxidants, or thioester antioxidants.

[0052] Preferably, the auxiliary antioxidant includes any one or a combination of at least two of tris(2,4-di-tert-butylphenyl) phosphite, pentaerythritol bis(di(2,4-tert-butylphenyl) phosphite), bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite, dialkyl thiodipropionate, or pentaerythritol tetrakis(3-laurylthiopropionate).

[0053] In a second aspect, the present invention provides a method for preparing the polypropylene material described in the first aspect, and the preparation method includes the following steps:

[0054] Provide a modified nano-silica dispersion liquid, and the modified nano-silica dispersion liquid includes a combination of modified nano-silica and an organic solvent;

[0055] Mix the modified nano-silica dispersion liquid with polypropylene resin, pre-disperse until the organic solvent is removed, and then carry out internal mixing to obtain the polypropylene material.

[0056] The present invention uniformly disperses nano-silica into the polypropylene matrix to prevent the entanglement of polymer chains, reduce the degree of polymer entanglement, and thus macroscopically reduce the viscosity of polypropylene.

[0057] Preferably, the screw speed of the internal mixing is 40-60 r / min, such as 40 r / min, 42 r / min, 44 r / min, 46 r / min, 48 r / min, 50 r / min, 52 r / min, 54 r / min, 56 r / min, 58 r / min, 60 r / min, etc. Any other specific point value within this numerical range can be selected and will not be elaborated one by one here.

[0058] Preferably, the temperature of the internal mixing is 180-200 °C (such as 180 °C, 185 °C, 190 °C, 195 °C, 200 °C, etc.), and the time of the internal mixing is 4-6 min (such as 4 min, 4.5 min, 5 min, 5.5 min, 6 min, etc.). Any other specific point value within the above numerical range can be selected and will not be elaborated one by one here.

[0059] In a third aspect, the present invention provides a plastic part made of the polypropylene material described in the first aspect.

[0060] Compared with the prior art, the present invention has the following beneficial effects:

[0061] The propylene material involved in the present invention creatively disperses modified nano-silica evenly into the polypropylene matrix and introduces it into the entanglement network of molecular chains. Through the selective diffusion effect, the entanglement of polypropylene molecular chains is promoted to disentangle, so that the polypropylene resin significantly reduces the viscosity while maintaining toughness. At the same time, the present invention also creatively selects modified nano-silica particles of different sizes according to the melt flow rate of the polypropylene resin, further improving the flow performance and impact resistance of the polypropylene material. In addition, the raw materials used in the present invention are convenient to obtain, have a low price, a low additive amount of auxiliaries, have no toxic effect on the human body, and are safe, inexpensive and highly universal. The polypropylene material involved in the present invention can further reduce the viscosity of polypropylene and increase the upper limit of the melt index of the product on the basis of the existing petrochemical industry for synthesizing high-flow and high-impact polypropylene. Detailed implementation mode

[0062] To further elaborate on the technical means and effects adopted by the present invention, the following further illustrates the technical solution of the present invention in conjunction with the preferred embodiments of the present invention, but the present invention is not limited to the scope of the embodiments.

[0063] In the following embodiments, unless otherwise specified, the reagents and consumables used are purchased from conventional reagent manufacturers in the art; unless otherwise specified, the experimental methods and technical means used are conventional methods and means in the art.

[0064] Preparation Example 1

[0065] This preparation example provides a modified nano-silica, and the preparation method is as follows:

[0066] (1) The silica with a particle size of 8 nm (purchased from Aladdin Reagent (Shanghai) Co., Ltd.) is dried at 90 °C for 16 h, added to an ethanol-aqueous solution (the volume ratio of ethanol to water is 3:1), and after stirring, it is ultrasonically dispersed in an ultrasonic cleaner at 40 °C for 60 min to obtain an aqueous alcohol dispersion of silica.

[0067] (2) The silane coupling agent γ-methacryloxypropyltrimethoxysilane KH570 is added to an ethanol-aqueous solution (the volume ratio of ethanol to water is 9:1), the overall pH is adjusted to 4 with glacial acetic acid, and after stirring, it is allowed to stand at 40 °C for 60 min to pre-hydrolyze KH570 to obtain a KH570 aqueous alcohol solution.

[0068] (3) Place the aqueous-alcoholic dispersion of silica in a flask, heat it in a water bath at 70 °C, keep stirring, and slowly dropwise add the KH570 aqueous-alcoholic solution into the stirred aqueous-alcoholic dispersion of silica. After the addition is complete, keep heating and stirring, and continue the reaction for 4 h. After the reaction is completed, pour the dispersion into a centrifuge tube, centrifuge it at 5000 r / min for 8 minutes, take the supernatant, centrifuge it again at 8000 r / min for 8 minutes, continue to take the supernatant, centrifuge it at 15000 r / min for 8 minutes, take out the precipitate, and vacuum dry it in an oven at 70 °C for 48 h for standby.

[0069] Preparation Example 2

[0070] This preparation example provides a modified nano-silica, and the preparation method is as follows:

[0071] (1) Dry the silica with a particle size of 15 nm (purchased from Aladdin Reagent (Shanghai) Co., Ltd., product number S104597) at 90 °C for 16 h, add it to an ethanol-aqueous solution (the volume ratio of ethanol to water is 3:1), and ultrasonically disperse it in an ultrasonic cleaner at 45 °C for 50 min after stirring to obtain an aqueous-alcoholic dispersion of silica.

[0072] (2) Add the silane coupling agent γ-methacryloxypropyltrimethoxysilane KH570 to an ethanol-aqueous solution (the volume ratio of ethanol to water is 9:1), adjust the overall pH to 3.8 with glacial acetic acid, and let it stand at 45 °C for 50 min after stirring to pre-hydrolyze KH570 to obtain a KH570 aqueous-alcoholic solution.

[0073] (3) Place the aqueous-alcoholic dispersion of silica in a flask, heat it in a water bath at 65 °C, keep stirring, and slowly dropwise add the KH570 aqueous-alcoholic solution into the stirred aqueous-alcoholic dispersion of silica. After the addition is complete, keep heating and stirring, and continue the reaction for 5 h. After the reaction is completed, pour the dispersion into a centrifuge tube, centrifuge it at 5000 r / min for 8 minutes, take the supernatant, centrifuge it again at 8000 r / min for 8 minutes, continue to take the supernatant, centrifuge it at 15000 r / min for 8 minutes, take out the precipitate, and vacuum dry it in an oven at 70 °C for 48 h for standby.

[0074] Preparation Example 3

[0075] This preparation example provides a modified nano-silica, and the preparation method is as follows:

[0076] (1) Silica with a particle size of 30 nm (purchased from Aladdin Reagent (Shanghai) Co., Ltd., product number S104596) was dried at 90 °C for 16 h, then added to an ethanol-aqueous solution (volume ratio of ethanol to water is 3:1). After stirring, it was ultrasonically dispersed in an ultrasonic cleaner at 35 °C for 70 min to obtain an aqueous-alcohol dispersion of silica.

[0077] (2) The silane coupling agent γ-methacryloxypropyltrimethoxysilane KH570 was added to an ethanol-aqueous solution (volume ratio of ethanol to water is 9:1). The overall pH was adjusted to 4.2 with glacial acetic acid, and after stirring, it was left standing at 35 °C for 70 min to pre-hydrolyze KH570, obtaining an aqueous-alcohol solution of KH570.

[0078] (3) The aqueous-alcohol dispersion of silica was placed in a flask and heated in a water bath at 75 °C while maintaining stirring. The aqueous-alcohol solution of KH570 was slowly added dropwise to the stirred aqueous-alcohol dispersion of silica. After the addition was complete, heating and stirring were maintained, and the reaction continued for 3.5 h. After the reaction ended, the dispersion was poured into a centrifuge tube and centrifuged at 5000 r / min for 8 minutes. The upper clear liquid was taken, and then centrifuged again at 8000 r / min for 8 minutes. The upper clear liquid was taken again and centrifuged at 15000 r / min for 8 minutes. The precipitate was taken out and vacuum dried in an oven at 70 °C for 48 h for standby.

[0079] Preparation Example 4

[0080] This preparation example provides a modified nano-silica, and the preparation method is as follows:

[0081] (1) Silica with a particle size of 12 nm (purchased from Macklin Reagent) was dried at 90 °C for 16 h, then added to an ethanol-aqueous solution (volume ratio of ethanol to water is 3:1). After stirring, it was ultrasonically dispersed in an ultrasonic cleaner at 40 °C for 60 min to obtain an aqueous-alcohol dispersion of silica.

[0082] (2) The silane coupling agent γ-methacryloxypropyltrimethoxysilane KH570 was added to an ethanol-aqueous solution (volume ratio of ethanol to water is 9:1). The overall pH was adjusted to 4 with glacial acetic acid, and after stirring, it was left standing at 40 °C for 60 min to pre-hydrolyze KH570, obtaining an aqueous-alcohol solution of KH570.

[0083] (3) Place the aqueous alcohol dispersion of silica in a flask, heat it in a water bath at 70 °C, keep stirring, and slowly dropwise add the KH570 aqueous alcohol solution into the stirred aqueous alcohol dispersion of silica. After the addition is complete, keep heating and stirring, and continue the reaction for 4 h. After the reaction is completed, pour the dispersion into a centrifuge tube, centrifuge it at 5000 r / min for 8 minutes, take the supernatant, centrifuge it again at 8000 r / min for 8 minutes, continue to take the supernatant, centrifuge it at 15000 r / min for 8 minutes, take out the precipitate, and vacuum dry it in an oven at 70 °C for 48 h for standby.

[0084] Preparation Example 5

[0085] This preparation example provides a modified nano-silica, and the preparation method is as follows:

[0086] (1) Dry the silica with a particle size of 5 nm (purchased from Macklin, product number S750127) at 90 °C for 16 h, add it to an ethanol-aqueous solution (volume ratio of ethanol to water is 3:1), and ultrasonically disperse it in an ultrasonic cleaner at 40 °C for 60 min to obtain an aqueous alcohol dispersion of silica.

[0087] (2) Add the silane coupling agent γ-methacryloxypropyltrimethoxysilane KH570 to an ethanol-aqueous solution (volume ratio of ethanol to water is 9:1), adjust the overall pH to 4 with glacial acetic acid, stir and let it stand at 40 °C for 60 min to pre-hydrolyze KH570, and obtain a KH570 aqueous alcohol solution.

[0088] (3) Place the aqueous alcohol dispersion of silica in a flask, heat it in a water bath at 70 °C, keep stirring, and slowly dropwise add the KH570 aqueous alcohol solution into the stirred aqueous alcohol dispersion of silica. After the addition is complete, keep heating and stirring, and continue the reaction for 4 h. After the reaction is completed, pour the dispersion into a centrifuge tube, centrifuge it at 5000 r / min for 8 minutes, take the supernatant, centrifuge it again at 8000 r / min for 8 minutes, continue to take the supernatant, centrifuge it at 15000 r / min for 8 minutes, take out the precipitate, and vacuum dry it in an oven at 70 °C for 48 h for standby.

[0089] The sources of the materials used in the following examples and comparative examples are as follows:

[0090] The polypropylene resin SP179 is purchased from Lanzhou Petrochemical, MFR = 10.5 g / 10 min (230 °C, 2.16 kg);

[0091] The polypropylene resin KF-BM188C is purchased from Ningbo Jinfa, MFR = 15 g / 10 min (230 °C, 2.16 kg);

[0092] Polypropylene resin K9930H was purchased from Lanzhou Petrochemical, MFR = 28.9 g / 10 min (230 ° C, 2.16 kg);

[0093] Polypropylene resin PPB-M24-G was purchased from Guangzhou Petrochemical, MFR = 23g / 10min (230°C, 2.16kg);

[0094] Polypropylene resin KF-K8003 was purchased from Ningbo Jinfa, MFR = 3 g / 10 min (230 ° C, 2.16 kg);

[0095] The primary antioxidant SONOX 1010 and the secondary antioxidant SONOX 168 were purchased from Sanfeng Chemical;

[0096] White oil was purchased from Beite Chemical, brand 10# white oil;

[0097] Sodium stearate was purchased from Aladdin with the brand number S598934.

[0098] Examples 1 to 21, Comparative Examples 1 to 11

[0099] The above embodiments and comparative examples respectively provide a polypropylene material, and the composition and weight proportions thereof are shown in Tables 1-3.

[0100] The preparation methods of the polypropylene materials in the above embodiments and comparative examples are as follows:

[0101] The modified nano-silica was dissolved in anhydrous ethanol and ultrasonically dispersed for 2 hours. Then, polypropylene resin, primary antioxidant SONOX 1010 and secondary antioxidant SONOX 168 were added to the solution according to the proportions in Table 1-3, and pre-dispersed at 40°C for 6 hours until the ethanol was completely evaporated to obtain a polypropylene / silica mixture. The mixture was then mixed with white oil and sodium stearate in a premixer, and then mixed and dispersed by a Brabender mixer, wherein the screw speed was 50r / min, the mixing temperature was 190°C, and the mixing time was 5min to obtain a polypropylene material.

[0102] Table 1

[0103]

[0104]

[0105] Table 2

[0106]

[0107] Table 3

[0108]

[0109] The polypropylene materials prepared in Examples 1 - 21 and Comparative Examples 1 - 9 were subjected to performance tests.

[0110] (1) Melt flow rate test: Referring to ISO - 1133, the test conditions were 230 °C and 2.16 kg. The larger the melt mass - flow rate value (MFR), the lower the viscosity of the product.

[0111] (2) Toughness test: Referring to ISO 179 - 1, injection - molded ISO standard mechanical splines were used to measure the notched Izod impact strength of the product at 23 °C.

[0112] As can be seen from the data in Table 1 - 2, compared with the polypropylene resin SP179, the polypropylene materials provided by the present invention had a significantly increased MFR, and at the same time, retained a relatively high notched impact strength. The obtained polypropylene materials had high flowability and impact resistance.

[0113] Comparing the data of Examples 1, 9 - 12 and Comparative Examples 1 - 2, for polypropylene resins with 5 g / 10 min ≤ MFR < 20 g / 10 min, when the addition amount of modified nano - silica was the same, choosing silica with a size of 15 nm significantly improved the flowability and impact resistance of the polypropylene resin compared to silica particles with sizes of 8 nm and 30 nm.

[0114] Comparing the data of Example 1 and Examples 6 - 7, white oil and sodium stearate achieved a synergistic effect in improving the flowability and impact resistance of the polypropylene resin; comparing the data of Example 1 and Example 8, choosing the combination of white oil and sodium stearate as the dispersion aid achieved a better effect in improving the fluidity and impact resistance of the polypropylene resin compared to other dispersion aids.

[0115] Comparing the data of Example 1 and Comparative Example 3, adding unmodified nano - silica to the polypropylene resin would instead increase the viscosity of the polypropylene resin and reduce its flowability and impact resistance.

[0116] As can be seen from the data in Table 3, compared with the polypropylene resin K9930H, the polypropylene materials provided by the present invention had a significantly increased MFR, and at the same time, retained a relatively high notched impact strength. The obtained polypropylene materials had high flowability and impact resistance.

[0117] Comparing the data of Example 18 and Comparative Examples 6 - 7, for polypropylene resins with 20 g / 10 min ≤ MFR ≤ 40 g / 10 min, choosing silica with a size of 5 - 10 nm significantly improved the flowability and impact resistance of the polypropylene resin compared to silica particles with sizes of 15 nm and 30 nm.

[0118] Comparing the data of Comparative Example 1 and Comparative Example 8, it can be seen that when the addition amount of the modified nano-silica is too much, it will instead increase the viscosity of the polypropylene resin and reduce the fluidity of the polypropylene resin.

[0119] The applicant declares that the technical solution of the present invention is illustrated by the above embodiments, but the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvement to the present invention, the equivalent substitution of each raw material of the product of the present invention, the addition of auxiliary components, the selection of specific methods, etc. all fall within the protection scope and the disclosure scope of the present invention.

[0120] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0121] In addition, it should be noted that in the various specific technical features described in the above specific embodiments, without conflict, they can be combined in any appropriate manner. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods.

Claims

1. A polypropylene material, characterized in that: The polypropylene material comprises the following components in parts by weight: Polypropylene resin 96.2-99.63 parts; 0.1-2 parts of silane coupling agent modified nano silicon dioxide; Dispersing aid 0.07-1.4 parts; The polypropylene resin has a melt flow rate (MFR) of 5-40 g / 10 min at 230° C. and 2.16 kg; When the MFR of the polypropylene resin satisfies 5g / 10min≤MFR<20g / 10min, the particle size of the modified nano-silicon dioxide is 10-20nm; When the MFR of the polypropylene resin satisfies 20g / 10min≤MFR≤40g / 10min, the particle size of the modified nano-silicon dioxide is 5-10nm.

2. The polypropylene material according to claim 1, characterized in that: The silane coupling agent includes any one or a combination of at least two of a silane coupling agent containing an unsaturated double bond, an aminopropyl silane coupling agent or a mercaptopropyl silane coupling agent, and is more preferably a silane coupling agent containing an unsaturated double bond; Preferably, the silane coupling agent containing unsaturated double bonds includes any one of vinyltrimethoxysilane, vinyltriethoxysilane or γ-methacryloxypropyltrimethoxysilane, or a combination of at least two thereof.

3. The polypropylene material according to claim 1, characterized in that: The modified nano silicon dioxide is prepared by a method comprising the following steps: The silane coupling agent solution and the nano-silicon dioxide dispersion are mixed and reacted to obtain the modified nano-silicon dioxide.

4. The polypropylene material according to claim 3, characterized in that: The mass ratio of the silane coupling agent to the nano-silicon dioxide is 1:(15-25); Preferably, the silane coupling agent solution is obtained by mixing a silane coupling agent with an ethanol aqueous solution, adjusting the pH to 3.5-4.5, and standing at 35-45° C. for 40-80 minutes for hydrolysis; Preferably, the silicon dioxide dispersion is obtained by mixing dried silicon dioxide with an ethanol aqueous solution and ultrasonically dispersing the mixture at 35-45° C. for 40-80 min. Preferably, the mixing and reaction are carried out under heating and stirring at 65-75°C; Preferably, the reaction time is 3-5 h.

5. The polypropylene material according to claim 1, characterized in that: The dispersing aid includes any one of white oil, sodium stearate or silicone, or a combination of at least two thereof; Preferably, the dispersing aid is a combination of white oil and sodium stearate; Preferably, the mass ratio of the white oil to sodium stearate is (1-3):

1.

6. The polypropylene material according to claim 1, characterized in that: The polypropylene material further comprises 0.1-0.2 parts by weight of a primary antioxidant; Preferably, the primary antioxidant comprises a hindered phenol antioxidant and / or a hydroxylamine antioxidant; Preferably, the hindered phenol antioxidant comprises any one or a combination of at least two of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]pentaerythritol ester, tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate, 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate octadecyl alcohol ester, ethylene bis(oxyethylene)bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate] or 3,9-bis[1,1-dimethyl-2-[(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane; Preferably, the hydroxylamine antioxidant comprises bis(octadecyl)hydroxylamine.

7. The polypropylene material according to claim 1, characterized in that: The polypropylene material further comprises 0.1-0.2 parts by weight of a secondary antioxidant; Preferably, the auxiliary antioxidant includes any one or a combination of at least two of a phosphite antioxidant, a phosphate antioxidant or a thioester antioxidant; Preferably, the auxiliary antioxidant includes any one of tris(2,4-di-tert-butylphenyl)phosphite, pentaerythritol bis(2,4-tert-butylphenyl)phosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphate, dialkyl thiodipropionate or pentaerythritol tetrakis(3-laurylthiopropionate) or a combination of at least two thereof.

8. A method for preparing the polypropylene material according to claim 1, characterized in that: The preparation method comprises the following steps: Providing a modified nano-silicon dioxide dispersion, wherein the modified nano-silicon dioxide dispersion comprises a combination of modified nano-silicon dioxide and an organic solvent; The modified nano-silicon dioxide dispersion is mixed with polypropylene resin, and pre-dispersed until the organic solvent is removed to obtain a mixture of polypropylene and modified silicon dioxide; The polypropylene and modified silicon dioxide mixture are uniformly mixed with a dispersing aid and then kneaded to obtain the polypropylene material.

9. The preparation method according to claim 8, characterized in that: The screw speed of the internal mixing is 40-60r / min; Preferably, the banburying temperature is 180-200° C., and the banburying time is 4-6 min.

10. A plastic article made of the polypropylene material according to any one of claims 1 to 7.

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