Preparation method and application of high-gloss transparent impact-resistant polypropylene

Abstract

The present invention belongs to the technical field of modified polypropylene, and in particular, relates to a method for preparing high-gloss transparent impact-resistant polypropylene and its application, the method comprising: (1) contacting a catalyst system with propylene for polymerization reaction to produce homopolymerized polypropylene; (2) continuing to introduce a mixed monomer of ethylene and propylene into the system for polymerization reaction to produce an impact-resistant polypropylene product I; (3) mixing the impact-resistant polypropylene product I with n-heptane and stirring to dissolve, then extracting, filtering, and drying to obtain an impact-resistant polypropylene product II; (4) blending the impact-resistant polypropylene product II with transparent polypropylene, a compatibilizer, an antioxidant, an acid absorber, and a nucleating agent, and then extruding and granulating the polypropylene composite material to obtain the high-gloss transparent impact-resistant polypropylene. The method of the present invention can realize that the impact-resistant polypropylene has high gloss, high transparency, low haze, and excellent rigidity and toughness, ensures the balance of various properties, and comprehensively improves product quality.

Description

Technical Field

[0001] The invention belongs to the technical field of modified polypropylene, and in particular relates to a preparation method and application of high-gloss transparent impact-resistant polypropylene. Background Art

[0002] High-gloss, transparent impact-resistant polypropylene means that on the basis of achieving product impact resistance and rigidity, the product composition is optimized, the product's microstructure is changed, the product's high gloss is achieved, and the product's gloss and transparency are further improved through modification.

[0003] At present, the fields of home appliances, automobiles, household goods, etc. have demands for product impact resistance, rigidity, glossiness, and transparency, but the performance indicators in these aspects often conflict with and influence each other.

[0004] In the art, by adding a certain amount of toughening agents, such as POE, TPO, rubber particles, etc., to homopolymer polypropylene or impact-resistant polypropylene, the impact resistance of the material is improved to a certain extent, but the gloss and transparency of the product are greatly reduced, and the end-users' requirements for product appearance cannot be met. In this regard, if a polypropylene product with high gloss and excellent rigidity-toughness balance can be made, and modified on this basis to improve the transparency, a high-gloss, transparent, impact-resistant polypropylene product can be developed, so that the mechanical and optical properties of the product are improved simultaneously, and the performance requirements for polypropylene products in the fields of home appliances, automobiles, and daily necessities can be met.

[0005] The patent document with publication number CN112745583A provides a high-gloss impact-resistant polypropylene composition and its preparation method and application, wherein propylene, a catalyst, an electron donor and a co-catalyst are mixed, and a first polymerization reaction is carried out to obtain a polypropylene slurry; the polypropylene slurry is then mixed with ethylene, and a second polymerization reaction is carried out to obtain a copolymerized polypropylene powder; the copolymerized polypropylene powder, a primary antioxidant, an auxiliary antioxidant, an acid absorber and a nucleating agent are mixed to obtain a mixture, and then extruded and granulated to obtain a polypropylene composition. The preparation process of this invention is the same as the device production of the current mainstream polypropylene process and is not further modified subsequently, so it cannot well solve the contradictory relationship between high gloss and high impact resistance, and its product performance cannot significantly surpass the general products on the market.

[0006] The patent document with publication number CN111518357A provides a high-gloss impact-resistant transparent modified polypropylene and its preparation method and application. The raw materials used mainly include polypropylene, grafting monomers, free radical initiators, toughening agents, crosslinking agents, nucleating agents, antioxidants, and fillers. The prepared modified polypropylene material has the characteristics of high gloss, high impact resistance, and high transparency, and can be widely used in the fields of home appliance housings, transparent plates, transparent storage boxes, and transparent packaging materials. The invention uses a modified method to improve the gloss and transparency of polypropylene products, but there are crosslinking, grafting, degradation and other reactions in the extruder, which will inevitably increase the VOC and odor of the product, affecting the subsequent use experience and promotion scope.

[0007] Therefore, it is necessary to develop and study new products and / or supporting processing techniques to prepare high-gloss impact-resistant transparent polypropylene. Summary of the invention

[0008] The purpose of the present invention is to provide a preparation method and application of high-gloss transparent impact-resistant polypropylene in view of the problem that the mechanical and optical properties of transparent polypropylene products cannot be improved at the same time, so as to achieve high gloss, high transparency, low haze and excellent toughness of the impact-resistant polypropylene, improve transparency and gloss while maintaining excellent mechanical properties, ensure the balance of various properties, and comprehensively improve product quality.

[0009] In order to achieve the above object, the present invention provides the following technical solutions:

[0010] A method for preparing high-gloss transparent impact-resistant polypropylene comprises the following steps:

[0011] (1) contacting an olefin polymerization catalyst system with propylene monomer to carry out a polymerization reaction to produce homopolypropylene;

[0012] (2) continuing to introduce a mixed monomer of ethylene and propylene into the system after the reaction in step (1) is completed to carry out a polymerization reaction to produce an impact-resistant polypropylene product I (which has excellent rigidity and toughness properties);

[0013] (3) mixing the impact-resistant polypropylene product I with n-heptane, stirring and dissolving the mixture (this process can dissolve the random substances contained in the homopolymerized polypropylene part of the impact-resistant polypropylene and the non-crystallized ethylene-propylene random copolymer contained in the rubber phase), then extracting and filtering the material (using a Buchner funnel), and drying the filtered solids to obtain the impact-resistant polypropylene product II;

[0014] (4) Blending the impact-resistant polypropylene product II with transparent polypropylene, a compatibilizer, an antioxidant, an acid absorber and a nucleating agent to obtain a polypropylene composite material; and then extruding and granulating the polypropylene composite material using a melt extrusion process to obtain the high-gloss transparent impact-resistant polypropylene.

[0015] Conventional olefin polymerization catalysts in the art can be used to produce homopolypropylene. For example, in some embodiments, in step (1), an olefin polymerization main catalyst, a cocatalyst and an external electron donor are mixed to prepare an olefin polymerization catalyst system.

[0016] Among them, the types of main catalyst, co-catalyst and external electron donor can also be conventionally selected in the art. In some embodiments, the olefin polymerization catalyst system includes: a main catalyst (active component and main catalyst carrier), an external electron donor and a co-catalyst; for example, the olefin polymerization catalyst system may include titanium tetrachloride, a carrier MgCl2, diisopropyldimethoxysilane and triethylaluminum; wherein Al / Mg=3.5-4.5 (for example, 4.0, 4.2), Al / Si=3.5-4.5 (for example, 4.0, 4.2).

[0017] In some embodiments, in the olefin polymerization catalyst system of step (1), the olefin polymerization main catalyst is an olefin polymerization CS-2C type catalyst, the co-catalyst is triethylaluminum, and the external electron donor is diisopropyldimethoxysilane.

[0018] In some embodiments, in the olefin polymerization catalyst system, the ratio of each component is as follows:

[0019] The molar ratio of the Al content in the co-catalyst (triethylaluminum) to the titanium content in the main catalyst (Al / Ti) is 70-450 (e.g., 80, 100, 150, 180, 210, 240, 280, 300, 350, 400), preferably 200-250;

[0020] The mass ratio T / D of the co-catalyst (triethylaluminum) to the external electron donor (diisopropyldimethoxysilane) is 3-20 (e.g., 3.5, 4, 5, 6, 6.5, 8.5, 10, 15, 18), preferably 7.0-8.0.

[0021] The production of homopolypropylene can be carried out using conventional operating steps and process conditions in the art. In some embodiments, in step (1), based on the total molar amount of each component, the concentration of propylene is 99.0-99.9 mol% (e.g., 99.2 mol%, 99.4 mol%, 99.6 mol%), and the concentration of hydrogen is 0.1-1.0 mol% (0.15 mol%, 0.2 mol%, 0.5 mol%, 0.8 mol%).

[0022] In some embodiments, in step (1), the reaction temperature is 60-70° C. (eg, 65° C.), the reaction pressure is 3.0-3.4 MPa (eg, 3.2 MPa), and the reaction time is 30-60 min (eg, 40 min, 50 min).

[0023] In some embodiments, in step (2), the amount of the mixed monomers of ethylene and propylene added is based on the pressure of the reaction system, and the reaction pressure is controlled to be 1.2-1.4 MPa (eg, 1.3 MPa).

[0024] In some embodiments, after the reaction is stabilized, the pressure is released to 0.1 MPa and re-pressurized to 1.2-1.4 MPa (eg, 1.3 MPa) every 15-20 minutes to keep the gas phase composition in the reaction system (eg, reactor) relatively constant.

[0025] The present invention can ensure that the obtained impact-resistant polypropylene product I has excellent rigidity and toughness by regulating the addition process of the ethylene and propylene mixed monomers in step (2), thereby obtaining a high-performance base resin and providing conditions for the subsequent modification of the polypropylene composition.

[0026] In some embodiments, in step (2), in the mixed monomer of ethylene and propylene, C2 / (C2+C3) is 0.28-0.32, for example, 0.29, 0.3, 0.31.

[0027] In step (2), the selection and regulation of the monomer dosage can be achieved by adjusting the C2 / (C2+C3) ratio of the ethylene and propylene mixed monomers and controlling the pressure of the reaction system during the process of introducing the mixed monomers into the system.

[0028] In some embodiments, in step (2), the reaction temperature is 80-90° C. (eg, 85° C.), and the reaction time is 60-120 min (eg, 70 min, 80 min, 100 min).

[0029] In some embodiments, the melt flow rate of the impact-resistant polypropylene product I obtained in step (2) is 25-35 g / 10 min, for example, 26 g / 10 min, 28 g / 10 min, 30 g / 10 min, 32 g / 10 min.

[0030] In the method of the present invention, the pressure involved may be understood as absolute pressure.

[0031] In some embodiments, the treatment process conditions of step (3) include:

[0032] The mixing temperature is 50-70°C (e.g., 55°C, 60°C, 65°C);

[0033] The stirring rate is 40-50 rpm (e.g., 45 rpm);

[0034] The stirring time is 10-20 minutes (e.g., 15 minutes);

[0035] The extraction time is 10-30 minutes (e.g., 15 minutes, 20 minutes, 25 minutes);

[0036] The drying temperature is 50-70° C. (eg, 60° C.), and the drying time is 0.5-1 h (eg, 40 min).

[0037] The present invention can dissolve the random substances contained in the homopolymerized polypropylene part in the impact-resistant polypropylene and the partially non-crystallized ethylene-propylene random copolymer contained in the rubber phase through the treatment of step (3), thereby providing conditions and improvement basis for subsequent blending modification.

[0038] In some embodiments, in the polypropylene composition of step (4), the amount (by weight) of each component is as follows:

[0039] Impact-resistant polypropylene product II 100 parts,

[0040] Transparent polypropylene 5-25 parts (e.g., 6 parts, 8 parts, 10 parts, 15 parts, 20 parts, 24 parts),

[0041] Compatibilizer 0.08-0.15 parts (e.g., 0.085 parts, 0.09 parts, 0.1 parts, 0.12 parts, 0.14 parts),

[0042] Primary antioxidant 0.04-0.06 parts (e.g., 0.045 parts, 0.05 parts, 0.55 parts),

[0043] Auxiliary antioxidant 0.06-0.10 parts (for example, 0.065 parts, 0.07 parts, 0.8 parts),

[0044] Acid absorbent 0.02-0.04 parts (e.g., 0.025 parts, 0.03 parts, 0.35 parts),

[0045] 0.20-0.28 parts (e.g., 0.22 parts, 0.24 parts, 0.26 parts) of sorbitol nucleating agent,

[0046] Phosphate nucleating agent 0.04-0.08 parts (for example, 0.045 parts, 0.05 parts, 0.06 parts).

[0047] In some embodiments, the compatibilizer is 4-isopropylphenethyl stearate.

[0048] In some embodiments, the compatibilizer is prepared by esterification reaction of 4-isopropylphenylethanol and stearic acid.

[0049] In some embodiments, the preparation step of the compatibilizer comprises:

[0050] Dissolve stearic acid in propylene glycol butyl ether, then add 4-isopropylphenylethanol and dibutyltin dilaurate as a catalyst, heat the system to 75-85° C. (e.g., 80° C.) to react, extract and separate the obtained reaction product to obtain the stearic acid 4-isopropylphenylethyl ester; wherein,

[0051] The mass ratio of propylene glycol butyl ether to stearic acid is 3:1-6:1 (e.g., 4:1, 5:1);

[0052] The mass ratio of 4-isopropylphenylethanol to stearic acid is 2:1-5:1 (eg, 3:1, 4:1).

[0053] In some embodiments, the transparent polypropylene is selected from a propylene-butyl copolymer transparent polymer resin.

[0054] In some embodiments, the antioxidant is a primary antioxidant and / or a secondary antioxidant; the primary antioxidant is preferably antioxidant 1790, and the secondary antioxidant is preferably antioxidant 168.

[0055] In some embodiments, the acid absorbent is selected from hydrotalcite and / or stearate.

[0056] In some embodiments, the nucleating agent is selected from sorbitol nucleating agents and / or phosphate nucleating agents; the sorbitol nucleating agent is nucleating agent NHS-9999, and the phosphate nucleating agent is nucleating agent NHP-202.

[0057] In some embodiments, the extrusion granulation process uses a twin-screw extruder, and its model can be, for example, Haake parallel co-rotating twin-screw extruder EUROLAB 16, the screw speed is controlled at 270 rpm, the barrel has 10 sections, and the temperature range of each section is 200-250°C.

[0058] In another aspect, there is provided an application of high-gloss transparent impact-resistant polypropylene prepared by the preparation method as described above in the fields of home appliance housings, transparent plates, transparent storage boxes, and transparent packaging materials.

[0059] In the present invention, 4-isopropylbenzene ethyl stearate is selected as the compatibilizer in the composition, which can play the interfacial compatibility role of polypropylene homopolymer (continuous phase) and rubber phase (dispersed phase). The isopropyl group contained in the compatibilizer plays a role of compatibility with polypropylene, and the straight-chain alkane contained in the compatibilizer plays a role of compatibility with ethylene segments in the rubber phase. The improvement of their interfacial compatibility can further reduce the refractive index of the interface between the homopolymer and the rubber phase in the polypropylene, so that the gloss and transparency of the product are improved; at the same time, due to the improved compatibility between the rubber phase and the homopolymer, the stress concentration point when the product is impacted by an external force is reduced, thereby maintaining excellent stress cracking resistance and even having an improvement effect to a certain extent, that is, while improving the gloss and transparency, the impact resistance of the product is also improved.

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

[0061] In the base resin preparation stage, by regulating the process of adding ethylene and propylene mixed monomers, it is possible to ensure that the resulting impact-resistant polypropylene product I has excellent rigidity and toughness properties, and the high-performance base resin is obtained to provide conditions for the subsequent modification of the polypropylene composition.

[0062] In the modification stage of the polypropylene composition, on the one hand, the impact-resistant polypropylene product obtained by polymerization is dissolved in n-heptane, which can dissolve the random substances contained in the homopolymerized polypropylene part and the small molecular non-crystallized ethylene-propylene random copolymer contained in the rubber phase, so that the isotacticity of the homopolymerized part in the product after washing and filtration is further improved, and the long-chain copolymer with propylene-rich segments and ethylene-rich segments and partial crystallinity is retained in the rubber phase, which is not only easy to form a core-shell structure with the polypropylene of the homopolymerized part, but also the long-chain molecules therein can cross the crystal region and play the role of lacing molecules between the spherulites, thereby bringing about the improvement effect of the rigidity and toughness (impact resistance) of the product; on the other hand, stearic acid-4-isopropylphenyl ethyl ester as a compatibilizer can further improve the interface compatibility between the homopolymerized part after the dissolution treatment and the copolymerized part of the rubber phase, so that the rubber phase is evenly dispersed in the homopolymer, and the refractive index of the interface between the homopolymer and the rubber phase is reduced, thereby bringing about the improvement of the gloss and transparency of the product. The improvement of the interface compatibility will also have a positive effect on the mechanical properties of the product.

[0063] The combined effect of these aspects ultimately enables high gloss, high transparency, low haze and excellent toughness of impact-resistant polypropylene, ensuring a balance of various properties, comprehensively improving product quality and meeting application requirements. DETAILED DESCRIPTION

[0064] In order to understand the technical features and contents of the present invention in detail, the preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described in the embodiments, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described here.

[0065] <Source of raw materials>

[0066] Main catalyst: CS-2C catalyst produced by Yingkou Xiangyang Company;

[0067] Triethylaluminum was purchased from Yingkou Xiangyang Company;

[0068] Diisopropyldimethoxysilane was purchased from Lujing Chemical.

[0069] The compatibilizer is 4-isopropylbenzene ethyl stearate, and its preparation steps are as follows:

[0070] Stearic acid is dissolved in propylene glycol butyl ether, and the mass ratio of propylene glycol butyl ether to stearic acid is 5:1; then 4-isopropylphenylethanol is added into the system, and the mass ratio of 4-isopropylphenylethanol to stearic acid is 3:1; dibutyltin dilaurate is added into the system as a catalyst for esterification reaction, and the system is heated to 75-85°C for reaction; and the reaction product is extracted and separated to obtain stearic acid-4-isopropylphenylethyl ester.

[0071] Transparent polypropylene, purchased from Yulin Yannenghua's propylene-butane copolymer transparent resin material MT400B;

[0072] Antioxidants: antioxidant 1790 and antioxidant 168 purchased from Songyuan;

[0073] Acid absorbent, hydrotalcite DHT-4A purchased from Kyowa, Japan;

[0074] Nucleating agents: sorbitol nucleating agent NHS-9999 and phosphate nucleating agent NHP-202 purchased from Hubei Xinnanhua.

[0075] <Test Method>

[0076] Gloss, GB / T 9754-2007;

[0077] Light transmittance, GB / T 40415-2021;

[0078] Haze, GB / T 2410-2008;

[0079] Tensile yield strength, GB / T 1040.2-2006;

[0080] Flexural modulus, GB / T 9341-2008;

[0081] Izod impact strength, GB / T 1843-2008.

[0082] Example 1

[0083] (1) A 5 L polypropylene pilot reactor was replaced with nitrogen and then depressurized to 0.01 MPa, filled with 0.5 MPa hydrogen, and then 2.5 L of liquid propylene monomer was added;

[0084] Take 15 mg of CS-2C catalyst in a glove box, weigh triethylaluminum and diisopropyldimethoxysilane, control T / D=7.5 and Al / Ti=230, mix the three to form a catalyst system, and then inject into a small test reactor; adjust the stirring paddle speed in the reactor to 400 rpm, raise the temperature in the reactor to 70° C., control the pressure in the reactor to 3.2-3.4 MPa, carry out polymerization reaction and keep the reaction for 45 minutes, then release the pressure in the reactor to 0.01 MPa to obtain homopolypropylene;

[0085] (2) Then, the reactor was charged with a monomer mixture of ethylene and propylene, wherein C2 / (C2+C3) was 0.30, the pressure in the reactor was controlled to be 1.3 MPa, the temperature in the reactor was controlled to be 80° C., and a copolymerization reaction was started; after the reaction was stable, the pressure was reduced to 0.1 MPa and re-pressurized to 1.3 MPa every 15 minutes, and the gas phase composition in the reactor was kept relatively constant; after the copolymerization reaction lasted for 1 hour, the reaction was terminated, and the resulting impact-resistant polypropylene product I powder (with a melt flow rate of 30 g / 10 min) was discharged and collected;

[0086] (3) Pour the impact-resistant polypropylene product I powder into twice the volume of n-heptane, heat to 70° C. and stir to dissolve, the stirring speed is controlled to 50 rpm, and after stirring for 15 minutes, pour the resulting slurry into a Buchner funnel for extraction and filtration; after filtering off the n-heptane and dissolved matter, place the resulting solid in an oven and heat and dry at 70° C. for 30 minutes to obtain an impact-resistant polypropylene product II;

[0087] (4) Collecting 100 parts of the obtained impact-resistant polypropylene product II powder, and adding 5 parts of propylene-butyl copolymer transparent polypropylene MT400B, 0.12 parts of a compatibilizer (stearate-4-isopropylbenzene ethyl ester), 0.04 parts of a primary antioxidant 1790, 0.08 parts of a secondary antioxidant 168, 0.03 parts of an acid absorber DHT-4A, 0.25 parts of a sorbitol nucleating agent NHS-9999, and 0.05 parts of a phosphate nucleating agent NHP-202, and blending to obtain a polypropylene composite material;

[0088] The polypropylene composite material is then added to the feed port of the extruder, and the barrel temperature of each section of the extruder is set as shown in Table 1, and high-gloss, high-transparency, and impact-resistant polypropylene is obtained by extrusion granulation.

[0089] The high gloss and high transparency impact-resistant polypropylene was processed into strips and then tested for performance according to national standards. The test results are shown in Table 2.

[0090] Comparative Example 1

[0091] (1) A 5 L polypropylene pilot reactor was replaced with nitrogen and then depressurized to 0.01 MPa, filled with 0.5 MPa hydrogen, and then 2.5 L of liquid propylene monomer was added;

[0092] Take 15 mg of CS-2C catalyst in a glove box, weigh triethylaluminum and diisopropyldimethoxysilane, control T / D=7.5 and Al / Ti=230, mix the three to form a catalyst system, and then inject into a small test reactor; adjust the stirring paddle speed in the reactor to 400 rpm, raise the temperature in the reactor to 70° C., control the pressure in the reactor to 3.2-3.4 MPa, carry out polymerization reaction and keep the reaction for 45 minutes, then release the pressure in the reactor to 0.01 MPa to obtain homopolypropylene;

[0093] (2) Then, the reactor was charged with a monomer mixture of ethylene and propylene, wherein C2 / (C2+C3) was 0.30, the pressure in the reactor was controlled to be 1.3 MPa, the temperature in the reactor was controlled to be 80° C., and a copolymerization reaction was started; after the reaction was stable, the pressure was reduced to 0.1 MPa and re-pressurized to 1.3 MPa every 15 minutes, and the gas phase composition in the reactor was kept relatively constant; after the copolymerization reaction lasted for 1 hour, the reaction was terminated, and the resulting impact-resistant polypropylene product I powder (with a melt flow rate of 30 g / 10 min) was discharged and collected;

[0094] (3) 100 parts of the obtained impact-resistant polypropylene product I powder were collected, and 0.12 parts of a compatibilizer (stearate-4-isopropylbenzene ethyl ester), 0.04 parts of a primary antioxidant 1790, 0.08 parts of a secondary antioxidant 168, 0.03 parts of an acid absorber DHT-4A, 0.25 parts of a sorbitol nucleating agent NHS-9999, and 0.05 parts of a phosphate nucleating agent NHP-202 were added thereto, and transparent polypropylene copolymer MT400B was not added, and a polypropylene composite material was obtained after blending;

[0095] The polypropylene composite material is then added to the feed port of the extruder, and the barrel temperature of each section of the extruder is set as shown in Table 1, and the polypropylene product is obtained by extrusion granulation.

[0096] The polypropylene product was processed into strips and then tested for performance according to national standards. The test results are shown in Table 2.

[0097] Example 2

[0098] (1) A 5 L polypropylene pilot reactor was replaced with nitrogen and then depressurized to 0.01 MPa, filled with 0.5 MPa hydrogen, and then 2.5 L of liquid propylene monomer was added;

[0099] 15 mg of CS-2C catalyst was taken out of the glove box, triethylaluminum and diisopropyldimethoxysilane were weighed, T / D=7.5 and Al / Ti=230 were controlled, the three were mixed to form a catalyst system, and then injected into a small test reactor; the stirring paddle speed in the reactor was adjusted to 400 rpm, the temperature in the reactor was raised to 70° C., the pressure in the reactor was controlled at 3.2-3.4 MPa, a polymerization reaction was carried out, and the reaction was maintained for 45 minutes, and then the pressure in the reactor was released to 0.01 MPa to obtain homopolypropylene;

[0100] (2) Then, the reactor was charged with a monomer mixture of ethylene and propylene, wherein C2 / (C2+C3) was 0.30, the pressure in the reactor was controlled to be 1.3 MPa, the temperature in the reactor was controlled to be 80° C., and a copolymerization reaction was started; after the reaction was stable, the pressure was reduced to 0.1 MPa and re-pressurized to 1.3 MPa every 15 minutes, and the gas phase composition in the reactor was kept relatively constant; after the copolymerization reaction lasted for 1 hour, the reaction was terminated, and the resulting impact-resistant polypropylene product I powder (with a melt flow rate of 30 g / 10 min) was discharged and collected;

[0101] (3) Pour the impact-resistant polypropylene product I powder into twice the volume of n-heptane, heat to 70° C. and stir to dissolve, the stirring speed is controlled to 50 rpm, and after stirring for 15 minutes, pour the resulting slurry into a Buchner funnel for extraction and filtration; after filtering off the n-heptane and dissolved matter, place the resulting solid in an oven and heat and dry at 70° C. for 30 minutes to obtain an impact-resistant polypropylene product II;

[0102] (4) Collecting 100 parts of the obtained impact-resistant polypropylene product II powder, adding 10 parts of propylene-butyl copolymer transparent polypropylene MT400B, 0.12 parts of a compatibilizer (stearate-4-isopropylbenzene ethyl ester), 0.04 parts of a primary antioxidant 1790, 0.08 parts of a secondary antioxidant 168, 0.03 parts of an acid absorber DHT-4A, 0.25 parts of a sorbitol nucleating agent NHS-9999, and 0.05 parts of a phosphate nucleating agent NHP-202, and blending to obtain a polypropylene composite material;

[0103] The polypropylene composite material is then added to the feed port of the extruder, and the barrel temperature of each section of the extruder is set as shown in Table 1, and high-gloss, high-transparency, and impact-resistant polypropylene is obtained by extrusion granulation.

[0104] The high gloss and high transparency impact-resistant polypropylene was processed into strips and then tested for performance according to national standards. The test results are shown in Table 2.

[0105] Comparative Example 2

[0106] (1) A 5 L polypropylene pilot reactor was replaced with nitrogen and then depressurized to 0.01 MPa, filled with 0.5 MPa hydrogen, and then 2.5 L of liquid propylene monomer was added;

[0107] Take 15 mg of CS-2C catalyst in a glove box, weigh triethylaluminum and diisopropyldimethoxysilane, control T / D=7.5 and Al / Ti=230, mix the three to form a catalyst system, and then inject into a small test reactor; adjust the stirring paddle speed in the reactor to 400 rpm, raise the temperature in the reactor to 70° C., control the pressure in the reactor to 3.2-3.4 MPa, carry out polymerization reaction and keep the reaction for 45 minutes, then release the pressure in the reactor to 0.01 MPa to obtain homopolypropylene;

[0108] (2) Then, the reactor was charged with a monomer mixture of ethylene and propylene, wherein C2 / (C2+C3) was 0.30, the pressure in the reactor was controlled to be 1.3 MPa, the temperature in the reactor was controlled to be 80° C., and a copolymerization reaction was started; after the reaction was stable, the pressure was reduced to 0.1 MPa and re-pressurized to 1.3 MPa every 15 minutes, and the gas phase composition in the reactor was kept relatively constant; after the copolymerization reaction lasted for 1 hour, the reaction was terminated, and the resulting impact-resistant polypropylene product I powder (with a melt flow rate of 30 g / 10 min) was discharged and collected;

[0109] (3) Pour the impact-resistant polypropylene product I powder into twice the volume of n-heptane, heat to 70° C. and stir to dissolve, the stirring speed is controlled to 50 rpm, and after stirring for 15 minutes, pour the resulting slurry into a Buchner funnel for extraction and filtration; after filtering off the n-heptane and dissolved matter, place the resulting solid in an oven and heat at 70° C. for 30 minutes to obtain an impact-resistant polypropylene product II;

[0110] (4) 100 parts of the obtained impact-resistant polypropylene product II powder were collected, and 10 parts of propylene-butyl copolymer transparent polypropylene MT400B, 0.04 parts of primary antioxidant 1790, 0.08 parts of secondary antioxidant 168, 0.03 parts of acid absorber DHT-4A, 0.25 parts of sorbitol nucleating agent NHS-9999, and 0.05 parts of phosphate nucleating agent NHP-202 were added thereto, and no compatibilizer stearic acid-4-isopropylbenzene ethyl ester was added, and a polypropylene composite material was obtained after blending;

[0111] The polypropylene composite material is then added to the feed port of the extruder, and the barrel temperature of each section of the extruder is set as shown in Table 1, and the polypropylene product is obtained by extrusion granulation.

[0112] The polypropylene product was processed into strips and then tested for performance according to national standards. The test results are shown in Table 2.

[0113] Example 3

[0114] (1) A 5 L polypropylene pilot reactor was replaced with nitrogen and then depressurized to 0.01 MPa, filled with 0.5 MPa hydrogen, and then 2.5 L of liquid propylene monomer was added;

[0115] 15 mg of CS-2C catalyst was taken out of the glove box, triethylaluminum and diisopropyldimethoxysilane were weighed, T / D=7.5 and Al / Ti=230 were controlled, the three were mixed to form a catalyst system, and then injected into a small test reactor; the stirring paddle speed in the reactor was adjusted to 400 rpm, the temperature in the reactor was raised to 70° C., the pressure in the reactor was controlled at 3.2-3.4 MPa, a polymerization reaction was carried out, and the reaction was maintained for 45 minutes, and then the pressure in the reactor was released to 0.01 MPa to obtain homopolypropylene;

[0116] (2) Then, the reactor was charged with a monomer mixture of ethylene and propylene, wherein C2 / (C2+C3) was 0.30, the pressure in the reactor was controlled to be 1.3 MPa, the temperature in the reactor was controlled to be 80° C., and a copolymerization reaction was started; after the reaction was stable, the pressure was reduced to 0.1 MPa and re-pressurized to 1.3 MPa every 15 minutes, and the gas phase composition in the reactor was kept relatively constant; after the copolymerization reaction lasted for 1 hour, the reaction was terminated, and the resulting impact-resistant polypropylene product I powder (with a melt flow rate of 30 g / 10 min) was discharged and collected;

[0117] (3) Pour the impact-resistant polypropylene product I powder into twice the volume of n-heptane, heat to 70° C. and stir to dissolve, the stirring speed is controlled to 50 rpm, and after stirring for 15 minutes, pour the resulting slurry into a Buchner funnel for extraction and filtration; after filtering off the n-heptane and dissolved matter, place the resulting solid in an oven and heat and dry at 70° C. for 30 minutes to obtain an impact-resistant polypropylene product II;

[0118] (4) Collecting 100 parts of the obtained impact-resistant polypropylene product II powder, and adding 15 parts of propylene-butyl copolymer transparent polypropylene MT400B, 0.12 parts of a compatibilizer (stearate-4-isopropylbenzene ethyl ester), 0.04 parts of a primary antioxidant 1790, 0.08 parts of a secondary antioxidant 168, 0.03 parts of an acid absorber DHT-4A, 0.25 parts of a sorbitol nucleating agent NHS-9999, and 0.05 parts of a phosphate nucleating agent NHP-202, and blending to obtain a polypropylene composite material;

[0119] The polypropylene composite material is then added to the feed port of the extruder, and the barrel temperature of each section of the extruder is set as shown in Table 1, and high-gloss, high-transparency, and impact-resistant polypropylene is obtained by extrusion granulation.

[0120] The high gloss and high transparency impact-resistant polypropylene was processed into strips and then tested for performance according to national standards. The test results are shown in Table 2.

[0121] Example 4

[0122] (1) A 5 L polypropylene pilot reactor was replaced with nitrogen and then depressurized to 0.01 MPa, filled with 0.5 MPa hydrogen, and then 2.5 L of liquid propylene monomer was added;

[0123] Take 15 mg of CS-2C catalyst in a glove box, weigh triethylaluminum and diisopropyldimethoxysilane, control T / D=7.5 and Al / Ti=230, mix the three to form a catalyst system, and then inject into a small test reactor; adjust the stirring paddle speed in the reactor to 400 rpm, raise the temperature in the reactor to 70° C., control the pressure in the reactor to 3.2-3.4 MPa, carry out polymerization reaction and keep the reaction for 45 minutes, then release the pressure in the reactor to 0.01 MPa to obtain homopolypropylene;

[0124] (2) Then, the reactor was charged with a monomer mixture of ethylene and propylene, wherein C2 / (C2+C3) was 0.30, the pressure in the reactor was controlled to be 1.3 MPa, the temperature in the reactor was controlled to be 80° C., and a copolymerization reaction was started; after the reaction was stable, the pressure was reduced to 0.1 MPa and re-pressurized to 1.3 MPa every 15 minutes, and the gas phase composition in the reactor was kept relatively constant; after the copolymerization reaction lasted for 1 hour, the reaction was terminated, and the resulting impact-resistant polypropylene product I powder (with a melt flow rate of 30 g / 10 min) was discharged and collected;

[0125] (3) Pour the impact-resistant polypropylene product I powder into twice the volume of n-heptane, heat to 70° C. and stir to dissolve, the stirring speed is controlled to 50 rpm, and after stirring for 15 minutes, pour the resulting slurry into a Buchner funnel for extraction and filtration; after filtering off the n-heptane and dissolved matter, place the resulting solid in an oven and heat and dry at 70° C. for 30 minutes to obtain an impact-resistant polypropylene product II;

[0126] (4) Collecting 100 parts of the obtained impact-resistant polypropylene product II powder, adding 20 parts of propylene-butyl copolymer transparent polypropylene MT400B, 0.12 parts of a compatibilizer (stearate-4-isopropylbenzene ethyl ester), 0.04 parts of a primary antioxidant 1790, 0.08 parts of a secondary antioxidant 168, 0.03 parts of an acid absorber DHT-4A, 0.25 parts of a sorbitol nucleating agent NHS-9999, and 0.05 parts of a phosphate nucleating agent NHP-202, and blending to obtain a polypropylene composite material;

[0127] The polypropylene composite material is then added to the feed port of the extruder, and the barrel temperature of each section of the extruder is set as shown in Table 1, and high-gloss, high-transparency, and impact-resistant polypropylene is obtained by extrusion granulation.

[0128] The high gloss and high transparency impact-resistant polypropylene was processed into strips and then tested for performance according to national standards. The test results are shown in Table 2.

[0129] Example 5

[0130] (1) A 5 L polypropylene pilot reactor was replaced with nitrogen and then depressurized to 0.01 MPa, filled with 0.5 MPa hydrogen, and then 2.5 L of liquid propylene monomer was added;

[0131] 15 mg of CS-2C catalyst was taken out of the glove box, triethylaluminum and diisopropyldimethoxysilane were weighed, T / D=7.5 and Al / Ti=230 were controlled, the three were mixed to form a catalyst system, and then injected into a small test reactor; the stirring paddle speed in the reactor was adjusted to 400 rpm, the temperature in the reactor was raised to 70° C., the pressure in the reactor was controlled at 3.2-3.4 MPa, a polymerization reaction was carried out, and the reaction was maintained for 45 minutes, and then the pressure in the reactor was released to 0.01 MPa to obtain homopolypropylene;

[0132] (2) Then, the reactor was charged with a monomer mixture of ethylene and propylene, wherein C2 / (C2+C3) was 0.30, the pressure in the reactor was controlled to be 1.3 MPa, the temperature in the reactor was controlled to be 80° C., and a copolymerization reaction was started; after the reaction was stable, the pressure was reduced to 0.1 MPa and re-pressurized to 1.3 MPa every 15 minutes, and the gas phase composition in the reactor was kept relatively constant; after the copolymerization reaction lasted for 1 hour, the reaction was terminated, and the resulting impact-resistant polypropylene product I powder (with a melt flow rate of 30 g / 10 min) was discharged and collected;

[0133] (3) Pour the impact-resistant polypropylene product I powder into twice the volume of n-heptane, heat to 70° C. and stir to dissolve, the stirring speed is controlled to 50 rpm, and after stirring for 15 minutes, pour the resulting slurry into a Buchner funnel for extraction and filtration; after filtering off the n-heptane and dissolved matter, place the resulting solid in an oven and heat and dry at 70° C. for 30 minutes to obtain an impact-resistant polypropylene product II;

[0134] (4) Collecting 100 parts of the obtained impact-resistant polypropylene product II powder, adding 25 parts of propylene-butyl copolymer transparent polypropylene MT400B, 0.12 parts of a compatibilizer (stearate-4-isopropylbenzene ethyl ester), 0.04 parts of a primary antioxidant 1790, 0.08 parts of a secondary antioxidant 168, 0.03 parts of an acid absorber DHT-4A, 0.25 parts of a sorbitol nucleating agent NHS-9999, and 0.05 parts of a phosphate nucleating agent NHP-202, and blending to obtain a polypropylene composite material;

[0135] The polypropylene composite material is then added to the feed port of the extruder, and the barrel temperature of each section of the extruder is set as shown in Table 1, and high-gloss, high-transparency, and impact-resistant polypropylene is obtained by extrusion granulation.

[0136] The high gloss and high transparency impact-resistant polypropylene was processed into strips and then tested for performance according to national standards. The test results are shown in Table 2.

[0137] Example 6

[0138] The preparation process of high gloss and high transparency impact-resistant polypropylene is similar to that of Example 1, except that the amount of compatibilizer added in step (4) is 0.08 parts.

[0139] The obtained high gloss and high transparency impact-resistant polypropylene was processed into specimens and then tested for performance according to national standards. The test results are shown in Table 2.

[0140] Example 7

[0141] The preparation process of high gloss and high transparency impact-resistant polypropylene is similar to that of Example 1, except that the amount of compatibilizer added in step (4) is 0.15 parts.

[0142] The obtained high gloss and high transparency impact-resistant polypropylene was processed into specimens and then tested for performance according to national standards. The test results are shown in Table 2.

[0143] As in the above embodiments and comparative examples, the added parts of each component in the polypropylene composite material are all parts by weight.

[0144] Table 1 Extruder barrel temperature at each section

[0145] Barrel temperature 1 segment 2nd segment 3 sections 4 paragraphs 5th paragraph 6 segments 7 segments 8 segments 9 segments 10 segments Temperature / ℃ 210 220 240 235 235 230 230 230 230 230

[0146] Table 2 Performance test data of the products obtained in each comparative example and embodiment

[0147]

[0148]

[0149] The performance test results in Table 2 show that by strictly controlling the proportion of reaction raw materials in the polymerization stage and regulating the process of adding reaction raw materials, a polypropylene base resin with excellent toughness and toughness properties is obtained, and the use of n-heptane to extract the random components in the impact-resistant polypropylene can make the polypropylene product have an ethylene-propylene block copolymer that can be partially crystallized, and then blended with a transparent propylene-butyl copolymer. At the same time, by adding a special compatibilizer to further improve the compatibility between the components in the blend, a modified polypropylene with high gloss, high transparency, and excellent toughness and toughness (tensile strength, modulus and impact toughness) can be prepared.

[0150] The above describes some embodiments of the present invention, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A method for preparing high gloss transparent impact-resistant polypropylene, characterized in that: The steps include: (1) contacting an olefin polymerization catalyst system with propylene monomer to carry out a polymerization reaction to produce homopolypropylene; (2) continuing to introduce a mixed monomer of ethylene and propylene into the system after the reaction in step (1) is completed to carry out a polymerization reaction to produce an impact-resistant polypropylene product I; (3) mixing the impact-resistant polypropylene product I with n-heptane, stirring and dissolving, then extracting and filtering the material, and drying the filtered solid to obtain the impact-resistant polypropylene product II; (4) blending the impact-resistant polypropylene product II with transparent polypropylene, a compatibilizer, an antioxidant, an acid absorber and a nucleating agent to obtain a polypropylene composite material; and then extruding and granulating the polypropylene composite material using a melt extrusion process to obtain the high-gloss transparent impact-resistant polypropylene; wherein: The compatibilizer is 4-isopropylphenylethyl stearate, which is prepared by esterification reaction of 4-isopropylphenylethanol and stearic acid.

2. The preparation method according to claim 1, characterized in that: In step (1), an olefin polymerization main catalyst, a co-catalyst and an external electron donor are mixed to prepare an olefin polymerization catalyst system.

3. The preparation method according to claim 2, characterized in that: The main catalyst for olefin polymerization is a CS-2C catalyst for olefin polymerization, the co-catalyst is triethylaluminum, and the external electron donor is diisopropyldimethoxysilane; In the olefin polymerization catalyst system, the ratio of each component is as follows: The molar ratio of the Al content in the co-catalyst to the titanium content in the main catalyst (Al / Ti) is 70-450; The mass ratio T / D of the co-catalyst to the external electron donor is 3-20.

4. The preparation method according to claim 3, characterized in that: In the olefin polymerization catalyst system, the ratio of each component is as follows: The molar ratio of the Al content in the co-catalyst to the titanium content in the main catalyst (Al / Ti) is 200-250; The mass ratio T / D of the co-catalyst to the external electron donor is 7.0-8.

0.

5. The preparation method according to claim 1, characterized in that: In step (1), the reaction temperature is 60-70° C., the reaction pressure is 3.2-3.4 MPa, and the reaction time is 30-60 min.

6. The preparation method according to claim 1, characterized in that: In step (2), the amount of the mixed monomers of ethylene and propylene added is based on the pressure of the reaction system, and the reaction pressure is controlled to be 1.2-1.4 MPa.

7. The preparation method according to claim 6, characterized in that: In step (2), after the reaction is stabilized, the pressure is released to 0.1 MPa and re-pressurized to 1.2-1.4 MPa every 15-20 minutes to keep the gas phase composition in the reaction system relatively constant.

8. The preparation method according to claim 1, characterized in that: In step (2), in the mixed monomer of ethylene and propylene, C2 / (C2+C3) is 0.28-0.

32.

9. The preparation method according to claim 1, characterized in that: In step (2), the reaction temperature is 80-90° C. and the reaction time is 60-120 min.

10. The preparation method according to claim 1, characterized in that: The melt flow rate of the impact-resistant polypropylene product I obtained in step (2) is 25-35 g / 10 min.

11. The preparation method according to claim 1, characterized in that: The processing conditions of step (3) include: The mixing temperature is 50-70°C; The stirring rate is 40-50 rpm; The stirring time is 10-20 minutes; The extraction time is 10-30 minutes; The drying temperature is 50-70℃ and the drying time is 0.5-1h.

12. The preparation method according to claim 1, characterized in that: The preparation steps of the compatibilizer include: Dissolve stearic acid in propylene glycol butyl ether, then add 4-isopropylphenylethanol and dibutyltin dilaurate as a catalyst, heat the system to 75-85°C for reaction, extract and separate the obtained reaction product to obtain the stearic acid 4-isopropylphenylethyl ester; wherein, The mass ratio of propylene glycol butyl ether to stearic acid is 3:1-6:1; The mass ratio of 4-isopropylphenylethanol to stearic acid is 2:1-5:

1.

13. The preparation method according to claim 1, characterized in that: The transparent polypropylene is selected from a transparent polymer resin of propylene-butyl copolymer; and / or The antioxidant is a primary antioxidant and / or a secondary antioxidant; the primary antioxidant is antioxidant 1790, and the secondary antioxidant is antioxidant 168; and / or The acid absorbent is selected from hydrotalcite and / or stearate; and / or The nucleating agent is selected from sorbitol nucleating agents and / or phosphate nucleating agents.

14. The preparation method according to claim 13, characterized in that: In the polypropylene composite material of step (4), the amounts of the components are as follows: Impact-resistant polypropylene product II 100 parts, Transparent polypropylene 5-25 parts, Compatibilizer 0.08-0.15 parts, Main antioxidant 0.04-0.06 parts, Auxiliary antioxidant 0.06-0.10 parts, Acid absorbent 0.02-0.04 parts, Sorbitol nucleating agent 0.20-0.28 parts, Phosphate nucleating agent 0.04-0.08 parts.

15. The preparation method according to claim 13 or 14, characterized in that: The sorbitol nucleating agent is the nucleating agent NHS-9999, and the phosphate nucleating agent is the nucleating agent NHP-202.

16. Application of high-gloss transparent impact-resistant polypropylene prepared by the preparation method according to any one of claims 1 to 15 in the fields of home appliance housings, transparent plates, transparent storage boxes, and transparent packaging materials.

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