Modified polypropylene based on multiphase non-uniform distribution of filler and preparation method of modified polypropylene

Abstract

The invention discloses modified polypropylene based on filler multiphase non-uniform distribution, which is prepared from the following raw materials in parts by mass: 69.1 to 89.7 parts of polypropylene, 5 to 15 parts of inorganic filler, 0.1 to 0.3 part of alpha nucleating agent, 0.1 to 0.3 part of beta nucleating agent, 5 to 15 parts of ethylene propylene rubber-polyolefin elastomer POE and 0.1 to 0.3 part of antioxidant, the inorganic filler is mainly distributed in an amorphous region in the modified polypropylene. The invention also discloses a preparation method of the modified polypropylene based on the multiphase non-uniform distribution of the filler. The raw materials of the modified polypropylene provided by the invention are easily available and cheap; in the modified polypropylene, an alpha / beta eutectic structure is formed instead of irregular spherocrystal, so that good adhesion of an interface can be ensured; moreover, the inorganic filler is distributed in a non-uniform state and is basically distributed in an amorphous region, so that the aim of improving the flowability and impact resistance of the material without influencing the rigidity of the material can be fulfilled.

Description

Technical Field

[0001] The invention belongs to the field of polypropylene materials, and in particular relates to modified polypropylene based on multi-phase non-uniform distribution of fillers and a preparation method thereof. Background Art

[0002] In addition to reducing the cost of products, the filling modification of polypropylene (PP) can also improve the heat resistance, rigidity, hardness, dimensional stability, creep resistance, wear resistance, flame retardancy, smoke suppression and degradability of products. However, the disadvantage of filling modification is also obvious, that is, it will greatly reduce the toughness of the material, especially the impact resistance. Although the performance of filling materials has been continuously improved with the gradual deepening of filler research in recent years, the continuous improvement of filler processing technology has continuously improved, but it has not really solved the problem of the trade-off between the toughness and rigidity of filling materials. Although with the continuous improvement of polypropylene nucleating agents, improving PP rigidity by promoting crystallization has become a widely used technology, but the high α orientation of PP crystals, like filler modification, will greatly lead to the loss of material toughness, and on the other hand, it also has a certain negative effect on the material processing temperature.

[0003] CN114031851A discloses a modified polypropylene for automobile interior and a preparation method thereof. Conventional polypropylene, high-impact polypropylene, inorganic filler, low-gloss material masterbatch, deodorant, antioxidant, light stabilizer, acid binder, lubricant, etc. are used to prepare a polypropylene modified material with good stability. The main goal is to produce less volatile organic compounds than traditional modified polypropylene for automobile interior.

[0004] CN113045823A discloses a talc-modified low-VOC, high-rigidity polypropylene material and a preparation method thereof. The talc masterbatch is made of polypropylene, specially treated talc and a lubricant, and then the modified polypropylene material is composited with polypropylene, a toughening agent and the talc masterbatch. Relying on the characteristics of the special talc powder with a large surface area and high activity, the tensile strength and tensile modulus, flexural strength and flexural modulus of the composite material can be greatly improved without losing the impact strength of the product.

[0005] CN110128748A discloses a high-toughness polypropylene material and a preparation method thereof, which is composed of polypropylene resin, coumarone resin, ethylene-octene copolymer and LDPE resin, and is a polypropylene material modified with coumarone resin, having good toughness, especially low-temperature toughness, as well as comprehensive properties such as high rigidity and dimensional stability.

[0006] CN110577612A discloses a method for producing a high melt index, high impact resistance and high rigidity polypropylene resin, which adopts the hydrogen adjustment method in the PP synthesis chemical plant and uses special additives to meet the requirements of high melt index, high rigidity and high impact resistance.

[0007] Some of the above-mentioned related technologies have different modification targets, some require corresponding measures to be taken in the synthesis stage, and the effect is general, either relying on special resins such as coumarone to complicate the material formula, or using special filler masterbatch method to ensure good uniform dispersion to obtain higher performance. There is no modification technology that adopts compound formula and processing technology to form a multi-phase composite non-uniform distribution structure in the material. Summary of the invention

[0008] Based on the above, the object of the present invention is to provide a modified polypropylene based on multi-phase non-uniform distribution of fillers and a preparation method thereof. Polypropylene is modified by multi-phase non-uniform distribution of fillers. In the modified polypropylene finally obtained, the talc is distributed in a non-uniform state, which can achieve the purpose of improving the fluidity and impact resistance of the material without affecting the rigidity of the material; the polypropylene forms an α / β eutectic structure rather than regular spherulites to ensure good adhesion of the interface.

[0009] To this end, in a first aspect, the present invention provides a modified polypropylene based on multi-phase non-uniform distribution of fillers, comprising an α / β eutectic polypropylene matrix and a non-uniformly distributed filling and toughening component, wherein the α / β eutectic polypropylene matrix is ​​prepared from polypropylene, an α nucleating agent, a β nucleating agent, and an antioxidant, and the filling and toughening component comprises an inorganic filler and an ethylene-propylene rubber-polyolefin elastomer POE. Calculated by weight, the raw materials comprise 69.1-89.7 parts of polypropylene, 5-15 parts of inorganic filler, 0.1-0.3 parts of α nucleating agent, 0.1-0.3 parts of β nucleating agent, 5-15 parts of ethylene-propylene rubber-polyolefin elastomer POE and 0.1-0.3 parts of antioxidant.

[0010] Specifically, an α / β eutectic structure is formed in the α / β eutectic polypropylene matrix, and the filling toughening component is mainly distributed in the amorphous region in the modified polypropylene. As a specific embodiment of the present invention, preferably, the modified polypropylene is made by extruding the α / β eutectic polypropylene matrix and the filling toughening component, and further preferably, the extrusion temperature is 170-200°C, and further preferably 180-190°C; and / or the extrusion screw speed is 250-350rpm.

[0011] As a specific embodiment of the present invention, preferably, the α / β eutectic polypropylene matrix is ​​made by extruding polypropylene and an α nucleating agent, a β nucleating agent and an antioxidant, and further preferably, the extrusion temperature is 210-230°C, and the extrusion screw speed is 150-200rpm; and / or the filling and toughening component is made by extruding ethylene-propylene rubber-polyolefin elastomer POE and an inorganic filler, and further preferably, the extrusion temperature is 170-190°C, and the extrusion screw speed is 150-200rpm.

[0012] As a specific embodiment of the present invention, preferably, the isotacticity of the polypropylene is not less than 95%, and according to GB / T3682.1-2018 standard, the melt index is 25-55 g / 10 min at 230° C. and 2.16 kg.

[0013] As a specific embodiment of the present invention, preferably, the inorganic filler is selected from at least one of wollastonite, mica, mineral powder fiber and talc powder, and more preferably, the inorganic filler is talc powder.

[0014] As a specific embodiment of the present invention, preferably, the particle size of the talc powder is 2500-10000 mesh; preferably H15 or HD5 of Mengdu Mining.

[0015] As a specific embodiment of the present invention, preferably, according to GB / T 3682.1-2018 standard, the melt index of the ethylene-propylene rubber-polyolefin elastomer POE is 3-15 g / 10 min at 230°C and 2.16 kg, preferably DF740 of Mitsui Chemicals.

[0016] As a specific embodiment of the present invention, preferably, the α nucleating agent, the β nucleating agent and the antioxidant are independently selected from commercially available brands; further preferably, the α nucleating agent is Milliken's 20E or 715, and / or the β nucleating agent is WINNER WBG-Ⅱ of Weilinna New Materials, and / or the antioxidant is BASF's 225.

[0017] To this end, in a second aspect, the present invention provides a method for preparing modified polypropylene based on multiphase non-uniform distribution of fillers, comprising the following steps:

[0018] (1) preparing polypropylene having an α / β eutectic structure by extruding polypropylene, an α nucleating agent, a β nucleating agent, and an antioxidant;

[0019] (2) preparing a filling and toughening component by extruding ethylene-propylene rubber-polyolefin elastomer POE and an inorganic filler;

[0020] (3) The polypropylene with α / β eutectic structure prepared in step (1) and the filling and toughening component prepared in step (2) are extruded to prepare modified polypropylene.

[0021] Specifically, the purpose of first preparing a polypropylene material component with an α / β eutectic structure is to prevent the main crystalline lattice of polypropylene from forming regular spherulites, thereby ensuring good adhesion of the interface. This modified polypropylene material has the characteristics of both high rigidity and high toughness.

[0022] As a specific embodiment of the present invention, preferably, the extrusion conditions in step (1) are: temperature 210-230° C., and screw speed 150-200 rpm.

[0023] As a specific embodiment of the present invention, preferably, the extrusion conditions in step (2) are: temperature 170-190° C., and screw speed 150-200 rpm.

[0024] As a specific embodiment of the present invention, preferably, the extrusion conditions in step (3) are: temperature 170-200°C, more preferably 180-190°C, and screw speed 250-350rpm; further preferably, extrusion is carried out in a high-torque high-speed extruder.

[0025] The present invention has the following advantages and beneficial effects:

[0026] (1) The modified polypropylene raw material provided by the present invention is easy to obtain and inexpensive; and in the modified polypropylene, an α / β eutectic structure is formed, rather than regular spherulites, which can ensure good adhesion of the interface; and the inorganic filler is distributed in a non-uniform state and is basically distributed in the amorphous region, which can achieve the purpose of improving the fluidity and impact resistance of the material without affecting the rigidity of the material. Therefore, the modified polypropylene provided by the present invention achieves a balance and collective improvement of the fluidity, rigidity and impact resistance of the modified polypropylene melt. That is, the modified polypropylene material of the present invention has the characteristics of both high rigidity and high toughness.

[0027] (2) The preparation method of the modified polypropylene provided by the present invention adopts a two-step method to prepare the modified polypropylene, which has simple production technology, uses a small amount of toughness component, and can be achieved by using traditional plastic modification processing methods.

[0028] (3) In the method for preparing modified polypropylene provided by the present invention, since the temperature during the extrusion process of polypropylene and the filling and toughening component in step (2) is relatively low, the dense PPα crystals are only broken up and not fully melted, while the PPβ crystals that form a eutectic with the PPα crystals have a relatively low melting point and are fully molecularly entangled with the filling and toughening component in the interface layer to form a stable connection. The inorganic filler is mainly distributed in this toughening zone, and the overall prepared polypropylene composite material has the characteristics of multi-phase non-uniform distribution. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a polarized microscopic magnified image of an ultrathin section of the modified polypropylene material prepared in Example 1.

[0030] in,

[0031] 1. Polypropylene α crystal; 2. Amorphous PP region; 3. Polypropylene α / β eutectic structure. DETAILED DESCRIPTION

[0032] The present invention will be further described below in conjunction with specific embodiments, but they do not constitute any limitation to the present invention.

[0033] In the following examples and comparative examples, the isotacticity of the polypropylene is 97%, and the melt index is 40 g / 10 min at 230°C and 2.16 kg; the talc is H15, 5000 mesh from Mondo Mining; the α nucleating agent is Milliken 20E; the β nucleating agent is WINNER WBG-Ⅱ from Weilinna New Materials; the copolymer POE is DF740 from Mitsui Chemicals, and the melt index is 3 g / 10 min at 230°C and 2.16 kg; and the antioxidant is 225 from BASF.

[0034] Example 1

[0035] Based on a modified polypropylene with heterogeneous distribution of fillers, it is prepared from the following components:

[0036] Polypropylene 69.1 parts,

[0037] 15 parts of talcum powder,

[0038] α nucleating agent 0.3 parts,

[0039] β-nucleating agent 0.3 parts,

[0040] Copolymer POE 15 parts,

[0041] 0.3 parts of antioxidant.

[0042] The preparation method is as follows:

[0043] Firstly, polypropylene, an α nucleating agent, a β nucleating agent and an antioxidant are added into a twin-screw extruder in proportion, and an α / β eutectic main polypropylene material is extruded at a processing temperature of 220° C. and a rotation speed of 180 rpm;

[0044] Then, the copolymerized olefin and talc are extruded in a twin-screw extruder at 180° C. and a rotation speed of 180 rpm to prepare a copolymerized olefin filling and toughening component;

[0045] Finally, the eutectic main polypropylene material and the copolymerized olefin filling toughening component are rapidly extruded in proportion in a high-torque high-speed extruder at a speed of 300 rpm at 190° C. to compound a multi-phase non-uniformly distributed modified polypropylene.

[0046] See the polarized light micrograph of the ultrathin slice of the modified polypropylene material prepared in Example 1. Figure 1 .Depend on Figure 1It can be seen that an α / β eutectic structure 3 is formed in the modified polypropylene, and the dense PPα crystals are only broken up (forming oriented and broken up polypropylene α crystals 1) but not fully melted. The PPβ crystals that form eutectics with the PPα crystals have a lower melting point and are fully entangled with the filling and toughening components in the interface layer to form a stable connection. In addition, talcum powder is basically distributed in the amorphous PP area 2. The overall prepared polypropylene composite material has the characteristics of multi-phase non-uniform distribution.

[0047] Example 2

[0048] Based on a modified polypropylene with heterogeneous distribution of fillers, it is prepared from the following components:

[0049] Polypropylene 89.7 parts,

[0050] 5 parts of talcum powder,

[0051] α nucleating agent 0.1 parts,

[0052] β-nucleating agent 0.1 parts,

[0053] Copolymer POE 5 parts,

[0054] Antioxidant 0.1 part.

[0055] The preparation method is as follows:

[0056] Firstly, polypropylene, an α nucleating agent, a β nucleating agent and an antioxidant are added into a twin-screw extruder in proportion, and extruded at a processing temperature of 220°C and a rotation speed of 180 rpm to prepare an α / β eutectic main polypropylene material; then, a copolymerized olefin and talcum powder are extruded in a twin-screw extruder at a temperature of 180°C and a rotation speed of 180 rpm to prepare a copolymerized olefin filling and toughening component; finally, the eutectic main polypropylene material and the copolymerized olefin filling and toughening component are rapidly extruded in proportion in a high-torque and high-speed extruder at a rotation speed of 300 rpm at a temperature of 190°C to prepare a multi-phase non-uniformly distributed modified polypropylene.

[0057] Example 3

[0058] Based on a modified polypropylene with heterogeneous distribution of fillers, it is prepared from the following components:

[0059] Polypropylene 79.1 parts,

[0060] 10 parts of talcum powder,

[0061] α nucleating agent 0.3 parts,

[0062] β-nucleating agent 0.3 parts,

[0063] Copolymer POE 10 parts,

[0064] 0.3 parts of antioxidant.

[0065] The preparation method is as follows:

[0066] Firstly, polypropylene, an α nucleating agent, a β nucleating agent and an antioxidant are added into a twin-screw extruder in proportion, and extruded at a processing temperature of 220°C and a rotation speed of 180 rpm to prepare an α / β eutectic main polypropylene material; then, a copolymerized olefin and talcum powder are extruded in a twin-screw extruder at a temperature of 180°C and a rotation speed of 180 rpm to prepare a copolymerized olefin filling and toughening component; finally, the eutectic main polypropylene material and the copolymerized olefin filling and toughening component are rapidly extruded in proportion in a high-torque and high-speed extruder at a temperature of 185°C and a rotation speed of 300 rpm to compound a multi-phase non-uniformly distributed modified polypropylene.

[0067] Comparative Example 1

[0068] Modified polypropylene is prepared from the following components:

[0069] Polypropylene 69.1 parts,

[0070] 15 parts of talcum powder,

[0071] α nucleating agent 0.3 parts,

[0072] β-nucleating agent 0.3 parts,

[0073] Copolymer POE 15 parts,

[0074] 0.3 parts of antioxidant.

[0075] The preparation method is as follows:

[0076] The above raw materials were directly added into a twin-screw extruder according to proportion, and the modified polypropylene material was extruded at a processing temperature of 220° C. and a rotation speed of 180 rpm. In this comparative example, all components were almost evenly dispersed.

[0077] Comparative Example 2

[0078] Modified polypropylene is prepared from the following components:

[0079] Polypropylene 79.1 parts,

[0080] 10 parts of talcum powder,

[0081] α nucleating agent 0.3 parts,

[0082] β-nucleating agent 0.3 parts,

[0083] Copolymer POE 10 parts,

[0084] 0.3 parts of antioxidant.

[0085] The preparation method is as follows:

[0086] The above raw materials were directly added into a twin-screw extruder according to proportion, and the modified polypropylene material was extruded at a processing temperature of 220° C. and a rotation speed of 180 rpm. In this comparative example, all components were almost evenly dispersed.

[0087] The modified polypropylene material and the modified polypropylene material prepared in the above examples and comparative examples were tested respectively, and the test results are listed in Table 1.

[0088] The test standards and conditions are as follows:

[0089] Bending performance test: According to GB / T 9341-2008 standard, the prepared specimens were subjected to a bending test.

[0090] Izod notched impact test: The impact performance test was performed on the prepared standard impact specimens according to GB / T 1843-2008.

[0091] Melt index test: The melt flow rate of the prepared material is tested at 230°C and 2.16 kg load according to GB / T 3682.1-2018.

[0092] Table 1

[0093]

[0094]

[0095] It can be seen from Table 1 that the modified polypropylene prepared in the example has higher flexural modulus, impact strength and melt index than that in the comparative example, and the minimum injection molding temperature is significantly reduced.

[0096] In summary, in the modified polypropylene provided by the present invention, the talc powder is distributed in a non-uniform state and is basically distributed in the amorphous region, which can achieve the purpose of improving the fluidity and impact resistance of the material without affecting the rigidity of the material; and the polypropylene forms an α / β eutectic structure rather than a regular spherulite, which can ensure good adhesion of the interface. Therefore, the modified polypropylene provided by the present invention achieves a balance and collective improvement of the melt fluidity, rigidity and impact resistance of the modified polypropylene.

[0097] The preparation method of modified polypropylene provided by the invention adopts a two-step method to prepare the modified polypropylene, has simple production technology, uses a small amount of toughness components, and can be achieved by adopting a traditional plastic modification processing method.

[0098] According to the preparation method of modified polypropylene provided by the present invention, since the temperature of the last high-speed extrusion process is low, the dense PPα crystals are only broken up and not fully melted, while the PPβ crystals forming eutectics with the PPα crystals have a low melting point and are fully entangled with the copolymerized olefin filling toughening component in the interface layer to form a stable connection, the filler is mainly distributed in this part of the toughening phase, and the overall prepared polypropylene composite material has the characteristics of multi-phase non-uniform distribution.

[0099] Any numerical value mentioned in the present invention, if there is only an interval of two units between any minimum value and any maximum value, includes all values ​​from the minimum value to the maximum value each time increasing by one unit. For example, if the amount of a component, or the value of a process variable such as temperature, pressure, time, etc. is declared to be 50-90, in this specification it means that 51-89, 52-88... and 69-71 and 70-71 are specifically listed. For non-integer values, 0.1, 0.01, 0.001 or 0.0001 can be appropriately considered as a unit. These are just some specially specified examples. In this application, in a similar manner, all possible combinations of numerical values ​​between the listed minimum and maximum values ​​are considered to have been disclosed.

[0100] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein, on the contrary, the present invention can be extended to all other methods and applications with the same functions.

Claims

1. A modified polypropylene based on heterogeneous distribution of fillers, characterized in that: The invention comprises an α / β eutectic polypropylene matrix and an unevenly distributed filling and toughening component. The α / β eutectic polypropylene matrix is ​​prepared from polypropylene, an α nucleating agent, a β nucleating agent and an antioxidant. The filling and toughening component comprises an inorganic filler and an ethylene-propylene rubber-polyolefin elastomer POE. Calculated by weight, the raw materials comprise 69.1-89.7 parts of polypropylene, 5-15 parts of inorganic filler, 0.1-0.3 parts of α nucleating agent, 0.1-0.3 parts of β nucleating agent, 5-15 parts of ethylene-propylene rubber-polyolefin elastomer POE and 0.1-0.3 parts of antioxidant.

2. The modified polypropylene according to claim 1, characterized in that The modified polypropylene is made by extruding an α / β eutectic polypropylene matrix and a filling and toughening component. Preferably, the extrusion temperature is 170-200° C., more preferably 180-190° C.; and / or the extrusion screw speed is 250-350 rpm.

3. The modified polypropylene according to claim 1 or 2, characterized in that: The α / β eutectic polypropylene matrix is ​​made by extruding polypropylene and an α nucleating agent, a β nucleating agent and an antioxidant. Preferably, the extrusion temperature is 210-230° C. and the extrusion screw speed is 150-200 rpm; and / or the filling and toughening component is made by extruding ethylene-propylene rubber-polyolefin elastomer POE and an inorganic filler. Preferably, the extrusion temperature is 170-190° C. and the extrusion screw speed is 150-200 rpm.

4. The modified polypropylene according to any one of claims 1 to 3, characterized in that: The isotacticity of the polypropylene is not less than 95%, and according to GB / T 3682.1-2018 standard, the melt index is 25-55 g / 10 min at 230° C. and 2.16 kg; and / or the inorganic filler is selected from at least one of wollastonite, mica, mineral powder fiber and talc.

5. The modified polypropylene according to claim 4, characterized in that The inorganic filler is talcum powder. Preferably, the particle size of the talcum powder is 2500-10000 mesh, and more preferably H15 or HD5 of Mengdu Mining.

6. The modified polypropylene according to any one of claims 1 to 5, characterized in that: According to GB / T3682.1-2018 standard, the melt index of the ethylene-propylene rubber-polyolefin elastomer POE is 3-15 g / 10 min at 230°C and 2.16 kg; and / or the α nucleating agent is Milliken's 20E or 715, and / or the β nucleating agent is WINNER WBG-Ⅱ of Weilinna New Materials, and / or the antioxidant is BASF's 225.

7. A method for preparing modified polypropylene based on multiphase non-uniform distribution of fillers according to any one of claims 1 to 6, characterized in that: The following steps are involved: (1) preparing polypropylene having an α / β eutectic structure by extruding polypropylene, an α nucleating agent, a β nucleating agent, and an antioxidant; (2) preparing a filling and toughening component by extruding ethylene-propylene rubber-polyolefin elastomer POE and an inorganic filler; (3) The polypropylene with α / β eutectic structure prepared in step (1) and the filling and toughening component prepared in step (2) are extruded to prepare modified polypropylene.

8. The preparation method according to claim 7, characterized in that: The extrusion conditions in step (1) are: temperature 210-230° C., and screw speed 150-200 rpm.

9. The preparation method according to claim 7 or 8, characterized in that: The extrusion conditions in step (2) are: temperature 170-190° C., and screw speed 150-200 rpm.

10. The preparation method according to any one of claims 7 to 9, characterized in that: The extrusion conditions in step (3) are: temperature 170°C-200°C, preferably 180°C-190°C, and screw speed 250-350 rpm; preferably, extrusion is carried out in a high-torque and high-speed extruder.

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