Thermoplastic elastomer and preparation method thereof

Abstract

The invention provides a thermoplastic elastomer and a preparation method thereof, the thermoplastic elastomer is formed by a raw material composition, and the raw material composition comprises the following components in parts by mass: 4-10 parts of polypropylene random copolymer, 0.1-1 part of a solubilizer, 0.1-1 part of a coupling agent, and 88-95 parts of a polyolefin elastomer. The impact resistance, tensile strength and other mechanical properties of the thermoplastic elastomer material can be improved.

Description

Technical Field

[0001] This invention relates to the field of polymer synthetic resins, and more specifically to a thermoplastic elastomer and its preparation method. Background Technology

[0002] Polyolefin elastomers (POEs) are thermoplastic elastomers generally produced by in-situ polymerization of ethylene and α-olefins under the action of a catalyst (such as a metallocene catalyst). They have a wide range of applications. For example, POE can be a random copolymer elastomer produced by polymerization of ethylene and high-carbon α-olefins under the action of a metallocene catalyst. This elastomer has a certain degree of crystallinity and features a relatively narrow molecular weight and low density. As another example, POE can be an ethylene-octene copolymer elastomer produced by copolymerizing ethylene and octene. Based on the total mass of ethylene and octene, the octene mass fraction is generally greater than 20%. Ethylene-octene copolymer elastomers have good compatibility with polyolefins (for example, they can be used as a modifier, compatible with polyolefins such as polypropylene and polyethylene), and are widely used in the automotive, footwear, wire and cable, packaging, polymer modification, and medical fields.

[0003] Improving the impact resistance and tensile strength of thermoplastic elastomers such as POE is crucial for their practical applications. In related technologies, modifying thermoplastic elastomers with additives such as impact modifiers can improve their impact resistance to some extent. Examples of impact modifiers include ethylene propylene rubber (EPR), EPDM, hydrogenated styrene-butadiene block copolymers, POE, and functionalized polyolefins. However, existing modification methods have limited effectiveness in improving the impact resistance of thermoplastic elastomers, and existing thermoplastic elastomers generally suffer from poor mechanical properties such as tensile strength. For instance, EPR and EPDM have good toughening efficiency, but their addition can impair the rigidity of thermoplastic elastomer materials, limiting their improvement on impact resistance and other properties, which is detrimental to large-scale production. Functionalized polyolefins have a slower toughening efficiency than POE, also limiting their effectiveness in improving the material's impact resistance.

[0004] In comparison, impact-modified POE (impact POE) is characterized by its narrow molecular weight distribution and low crystallinity. In its structure, the crystalline ethylene polymer unit segments (crystalline regions of the polyethylene chain) act as physical crosslinking points to bear the load, while the amorphous ethylene polymer units and α-olefin (such as butene) polymer unit branches contribute elasticity. This gives the thermoplastic elastomer better processing and mechanical properties. Furthermore, the molecular chain structure of impact-modified POE generally lacks unsaturated bonds, resulting in good thermal stability and weather resistance. Therefore, POE-based thermoplastic elastomers formed using impact POE have gradually gained widespread attention and application.

[0005] For example, patent document CN102532734A discloses a method for preparing structural weather-resistant and high-impact polystyrene. The method is carried out according to the following steps: 1) Preparation of graft masterbatch: Polystyrene, main-chain saturated rubber elastomer, Lewis acid composite catalyst, and co-catalyst are added to a mixing device; a melt grafting reaction is carried out at a temperature of 120℃~200℃ and a rotation speed of 20~200 rpm to finally obtain rubber elastomer grafted polystyrene masterbatch; 2) Preparation of weather-resistant and high-impact polystyrene: The rubber elastomer grafted polystyrene masterbatch obtained above is mixed with polystyrene in an appropriate proportion on a mixing device at a temperature of 160~220℃ to obtain structural weather-resistant and high-impact polystyrene, wherein the rubber elastomer can be a polyolefin elastomer (POE).

[0006] For example, CN1737049A discloses an in-situ compatibilized polystyrene / polyolefin elastomer blend and its preparation process. This method uses polystyrene, polyolefin elastomer, and compatibilizer as raw materials. The raw materials are mixed in a mixer for 10-20 minutes until homogeneous, according to their weight proportions. The mixture is then transferred to a twin-screw extruder for melt extrusion. The barrel temperature is: 150-170℃ in the filler zone, 165-185℃ in the mixing zone, and 170-190℃ in the reaction zone; the die temperature is 160-180℃; and the die pressure is 3-6 MPa. After extrusion, cooling and granulation yield a milky white cylindrical granule product. However, in this method, the compatibility between polystyrene and polyolefin elastomers (such as octenyl elastomers) is poor, which limits the toughening modification of the in-situ compatibilized polystyrene / polyolefin elastomer blend. The resulting in-situ compatibilized polystyrene / polyolefin elastomer blend still suffers from poor impact resistance and tensile strength.

[0007] Generally, the crystalline regions (resin phase) of polyethylene segments in POE act as physical crosslinking points, possessing certain plastic properties. The introduction of α-olefin (such as 1-butene, 1-hexene, 1-octene) polymeric segments weakens the crystalline regions of polyethylene segments. When impact-resistant POE is used to toughen thermoplastic elastomers, it can form a "sea-island" structure with good interfacial interaction with the brittle matrix of the thermoplastic elastomer. This allows the polyethylene-α-olefin blend system to absorb and release stress effectively when subjected to external impact. Specifically, the crystalline segments of impact-resistant POE can induce the formation of β-crystalline polypropylene (PP), increasing the thickness of the matrix crystalline layer; the amorphous phase is compatible with the amorphous regions of the brittle matrix, softening the brittle matrix and improving its toughness and impact resistance to some extent.

[0008] However, in related technologies, the poor balance between rigidity and toughness of the crystalline and amorphous phases in POE results in poor mechanical properties such as impact resistance and tensile strength of POE-type thermoplastic elastomers. Summary of the Invention

[0009] This invention provides a thermoplastic elastomer and its preparation method, which can improve the impact resistance and tensile strength of the thermoplastic elastomer and effectively overcome the defects of the prior art.

[0010] In one aspect, the present invention provides a thermoplastic elastomer formed from a raw material composition comprising the following components in parts by weight: 4 to 10 parts of random copolymer polypropylene, 0.1 to 1 part of solubilizer, 0.1 to 1 part of coupling agent, and 88 to 95 parts of polyolefin elastomer.

[0011] According to one embodiment of the present invention, the random copolymer polypropylene contains ethylene monomer units, and the mass percentage of the ethylene monomer units in the random copolymer polypropylene is greater than or equal to 2.5%; and / or, the melt index of the random copolymer polypropylene is 0.1 to 1.5 g / 10 min; and / or, the density of the random copolymer polypropylene is 0.90 to 0.91 g / cm³. 3 .

[0012] According to one embodiment of the present invention, the polyolefin elastomer is copolymerized from a second monomer raw material comprising ethylene and an α-olefin, wherein the α-olefin comprises 1-butene.

[0013] According to one embodiment of the present invention, the polyolefin elastomer comprises a butene-based elastomer copolymerized from ethylene and 1-butene; wherein the butene-based elastomer has a melt flow rate of 0.5–5.0 g / 10 min at 190°C and 2.16 kg; and / or, the mass percentage of 1-butene monomer units in the butene-based elastomer is greater than or equal to 15%; and / or, the density of the butene-based elastomer is 0.0862–0.885 g / cm³. 3 .

[0014] According to one embodiment of the present invention, the solubilizer comprises one or more of maleic anhydride-grafted polypropylene, maleic anhydride-grafted polyethylene, caprolactam diisocyanate, phenyl isocyanate, methyl methacrylate-grafted polydimethylsiloxane, and aluminum trichloride.

[0015] According to one embodiment of the present invention, the coupling agent comprises a silane coupling agent, wherein the silane coupling agent comprises γ-aminopropyltrimethoxysilane.

[0016] In another aspect, the present invention provides a thermoplastic elastomer and a method for preparing the same, comprising the following steps: mixing random copolymer polypropylene, solubilizer, coupling agent and polyolefin elastomer, and then sequentially performing intensive mixing and first granulation to obtain the thermoplastic elastomer.

[0017] According to one embodiment of the present invention, the mixing time is 15 to 30 minutes; and / or, the first granulation is performed using a first granulator, the temperature of the first granulator being 150 to 200°C and the rotation speed being 10 to 30 Hz.

[0018] According to one embodiment of the present invention, the preparation process of the polyolefin elastomer includes: polymerizing a first monomer raw material comprising ethylene and α-olefin under the action of a catalyst to obtain the polyolefin elastomer.

[0019] According to one embodiment of the present invention, the α-olefin comprises 1-butene; and / or, the catalyst comprises a Ziegler-Natta catalyst and / or a metallocene catalyst, preferably, the metallocene catalyst comprises a main catalyst and a co-catalyst, the main catalyst comprising a complex of a Group IVB transition metal and an alkylaluminoxane, and the co-catalyst comprising one or more of alkylaluminoxane, triisobutylaluminum, and organoboron compounds; and / or, the polymerization conditions are: a polymerization temperature of 130–190°C, a polymerization pressure of 4–8 MPa, and a polymerization time of 10–20 min; and / or, the polymerization is carried out in a solvent, the solvent comprising an alkane solvent.

[0020] The implementation of this invention has at least the following beneficial effects: by using a raw material composition comprising 4-10 parts of random copolymer polypropylene, 0.1-1 parts of solubilizer, 0.1-1 parts of coupling agent, and 88-95 parts of polyolefin elastomer to form a thermoplastic elastomer, the introduction of random copolymer polypropylene into the polyolefin elastomer increases the crystalline segments of the polyolefin elastomer, which is beneficial to the rigidity-toughness balance between the crystalline and amorphous phases in POE, thereby enhancing the rigidity of the polyolefin elastomer. At the same time, the random copolymer polypropylene and the polyolefin elastomer have good compatibility, which can improve the impact resistance and tensile strength of the polyolefin elastomer. Attached Figure Description

[0021] Figure 1 This is a SEM image of the thermoplastic elastomer of Example 1 of the present invention. Detailed Implementation

[0022] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below. The specific embodiments listed below are merely descriptions of the principles and features of the present invention, and the examples are only for explaining the present invention and are not intended to limit the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] This invention provides a thermoplastic elastomer formed from a raw material composition comprising the following components in parts by weight: 4-10 parts random copolymer polypropylene, 0.1-1 part solubilizer, 0.1-1 part coupling agent, and 88-95 parts polyolefin elastomer.

[0024] According to the inventors' research, using the above-mentioned raw material composition to form a thermoplastic elastomer can improve the impact resistance and tensile strength of the thermoplastic elastomer. The reason is that, on the one hand, the introduction of random copolymer polypropylene into the polyolefin elastomer increases the crystalline chain segments of the polyolefin elastomer, which is conducive to the rigidity and toughness balance between the crystalline and amorphous phases in POE and enhances the rigidity of the polyolefin elastomer. On the other hand, in the above-mentioned thermoplastic elastomer composition system, the random copolymer polypropylene and the polyolefin elastomer have good compatibility, thereby improving the impact resistance and tensile strength of the polyolefin elastomer.

[0025] Compared to homopolymer polypropylene, random copolymer polypropylene incorporates polymerization units formed by olefin monomers other than propylene into its polymer chain structure. This results in a more complex molecular structure and different properties such as flexibility and brittleness compared to homopolymer polypropylene (e.g., random copolymer polypropylene exhibits better flexibility and lower brittleness than homopolymer polypropylene). According to the inventors' research, in this embodiment of the invention, by adapting random copolymer polypropylene to components such as polyolefin elastomers, and based on the physical properties of random copolymer polypropylene and its synergistic effect with polyolefin elastomers, the impact resistance and tensile strength of the polyolefin elastomers can be significantly improved. Furthermore, the thermoplastic elastomer material can be obtained from the above-mentioned raw material composition through a first granulation process, specifically through extrusion granulation or other granulation methods. According to the inventors' research, in this embodiment of the invention, thermoplastic elastomer material (polyolefin elastomer) is used as the main raw material, and random copolymer polypropylene, coupling agent and solubilizer are introduced into it. The first granulation is carried out by extrusion granulation and other methods. In this process, the polymer segments in the polyolefin elastomer and random copolymer polypropylene and the coupling agent cross-link with each other, thereby controlling the microstructure and porosity of the formed thermoplastic elastomer. This is beneficial for the thermoplastic elastomer to have a suitable cell structure. When subjected to impact (e.g., high-speed impact), it can absorb and release stress through its cell structure (absorbing and storing energy when subjected to impact, and slowly releasing it after the impact load is removed), thus improving the impact resistance of the thermoplastic elastomer material.

[0026] For example, in the above-mentioned raw material composition, the mass fraction of random copolymer polypropylene can be in the range of 4, 5, 6, 7, 8, 9, 10 or any two of them; the mass fraction of solubilizer can be in the range of 0.1, 0.3, 0.5, 0.8, 1 or any two of them; the mass fraction of coupling agent can be in the range of 0.1, 0.3, 0.5, 0.8, 1 or any two of them; and the mass fraction of polyolefin elastomer can be in the range of 88, 89, 90, 91, 92, 93, 94, 95 or any two of them.

[0027] In some embodiments, the mass percentage of random copolymer polypropylene in the above-described raw material composition may be 4% to 10%, for example, a range of 4%, 5%, 6%, 7%, 8%, 9%, 10%, or any two of these.

[0028] In some embodiments, the mass percentage of the solubilizer in the above-described raw material composition may be 0.1% to 1%, for example, a range of 0.1%, 0.3%, 0.5%, 0.8%, 1%, or any two of these.

[0029] In some embodiments, the mass percentage of the coupling agent in the above-described raw material composition may be 0.1% to 1%, for example, a range of 0.1%, 0.3%, 0.5%, 0.8%, 1%, or any two of these.

[0030] In some embodiments, the mass percentage of polyolefin elastomer in the above-described raw material composition may be 88% to 95%, for example, a range of 88%, 90%, 92%, 94%, 95%, or any two of these.

[0031] Specifically, random copolymer polypropylene is polymerized from a first monomer raw material including propylene and other olefin monomers besides propylene. That is, random copolymer polypropylene contains propylene monomer units (or propylene polymerization units) formed by the polymerization of propylene and olefin monomer units (or olefin polymerization units) formed by the polymerization of other olefin monomers besides propylene.

[0032] Among them, other olefin monomers besides propylene may include ethylene (that is, the first monomer raw material may include ethylene), that is, random copolymer polypropylene can be copolymerized from the first monomer raw material including propylene and ethylene, that is, random copolymer polypropylene contains propylene monomer units (or propylene polymerization units) formed by the polymerization of propylene and ethylene monomer units (or ethylene polymerization units) formed by the polymerization of ethylene.

[0033] In some embodiments, the mass percentage of ethylene monomer units in the random copolymer polypropylene can be greater than or equal to 2.5%. Specifically, the mass percentage of ethylene monomer units in the random copolymer polypropylene can be 2.5% to 5%, for example, 2.5%, 2.7%, 2.9%, 3.1%, 3.3%, 3.5%, 3.7%, 4%, 4.3%, 4.5%, 5%, or any combination thereof, for example, 2.5% to 3.5%, which is beneficial for improving the impact resistance and tensile strength and other mechanical properties of the thermoplastic elastomer material.

[0034] In this embodiment of the invention, the mass percentage of ethylene monomer units in random copolymer polypropylene can be determined by nuclear magnetic resonance (NMR).

[0035] In specific implementation, the mass ratio of ethylene to the first monomer raw material used to polymerize and form random copolymer polypropylene (i.e., the mass of ethylene to the total mass of the first monomer raw material) can be greater than or equal to 2.5% (e.g., 2.5% to 5%), so that the mass percentage of ethylene monomer units in the formed random copolymer polypropylene is greater than or equal to 2.5% (e.g., 2.5% to 5%).

[0036] In some embodiments, the melt index of random copolymer polypropylene can be 0.1 to 1.5 g / 10 min, for example, a range of 0.1 g / 10 min, 0.3 g / 10 min, 0.5 g / 10 min, 0.8 g / 10 min, 1 g / 10 min, 1.3 g / 10 min, 1.5 g / 10 min or any combination thereof, which is beneficial for improving the impact resistance and tensile strength and other mechanical properties of thermoplastic elastomer materials.

[0037] In this embodiment of the invention, the melt index of components such as random copolymer polypropylene can be measured with reference to the GB / T20393-2006 standard.

[0038] In some embodiments, the density of the random copolymer polypropylene can be 0.90–0.91 g / cm³. 3 This is beneficial for improving the impact resistance and tensile strength of thermoplastic elastomer materials.

[0039] In this embodiment of the invention, the polyolefin elastomer can be copolymerized from a second monomer raw material comprising ethylene and α-olefin, that is, the polyolefin elastomer contains ethylene monomer units (or ethylene polymerization units) formed by the polymerization of ethylene and α-olefin monomer units (or α-olefin polymerization units) formed by the polymerization of α-olefin. The α-olefin may include 1-butene.

[0040] In some embodiments, the polyolefin elastomer may include a butene-based elastomer copolymerized from ethylene and 1-butene, which is beneficial for improving the impact resistance and tensile strength and other mechanical properties of the thermoplastic elastomer.

[0041] Specifically, the mass percentage of 1-butene monomer units in the butene-based elastomer can be greater than or equal to 15%, and the specific mass percentage of 1-butene monomer units in the butene-based elastomer can be 15% to 30%, for example, 15%, 20%, 25%, 30%, or any combination thereof. This is beneficial to improving the impact resistance and tensile strength of the thermoplastic elastomer. The reason for this is that by using a butene-based elastomer with a high 1-butene monomer unit content and compounding it with random copolymer polypropylene, solubilizers, and coupling agents, it is beneficial to improve the molecular structure and other properties of the formed thermoplastic elastomer, facilitate the uniform distribution of 1-butene monomer units and other branches in the polymer chain segments, and further facilitate the achievement of a rigidity-toughness balance between the crystalline and amorphous phases in the thermoplastic elastomer, thereby improving the impact resistance and tensile strength of the thermoplastic elastomer.

[0042] In specific implementation, the mass ratio of 1-butene to the second monomer raw material used for polymerization to form the butene-based elastomer (i.e., the mass of 1-butene to the total mass of the second monomer raw material) can be greater than or equal to 15% (e.g., 15% to 30%), so that the mass percentage of 1-butene monomer units in the formed butene-based elastomer is greater than or equal to 15% (e.g., 15% to 30%).

[0043] Furthermore, the melt flow rate (melt index) of butene-based elastomers at 190°C and 2.16 kg can be 0.5–5.0 g / 10 min, for example, 0.5 g / 10 min, 1 g / 10 min, 2 g / 10 min, 3 g / 10 min, 4 g / 10 min, 5 g / 10 min or any combination thereof, which is beneficial for improving the impact resistance and tensile strength and other mechanical properties of thermoplastic elastomers.

[0044] Furthermore, the density of butene-based elastomers can range from 0.0862 to 0.885 g / cm³. 3 For example, 0.0862 g / cm³ 3 0.1g / cm 3 0.2g / cm 3 0.3g / cm 3 0.4g / cm 3 0.5g / cm 3 0.6g / cm 3 0.7g / cm 3 0.8g / cm 3 0.885g / cm3 The range of either or both of these is beneficial for improving the impact resistance and tensile strength of thermoplastic elastomers.

[0045] In this embodiment of the invention, the solubilizer may include one or more of maleic anhydride-grafted polypropylene (PP-g-MAH), maleic anhydride-grafted polyethylene (PE-g-MAH), caprolactam diisocyanate (HDI), phenyl isocyanate (MDI), methyl methacrylate (MMA)-grafted polydimethylsiloxane (PDMS), and aluminum trichloride, which facilitates compatibility with components such as random copolymer polypropylene and polyolefin elastomers, thereby improving the impact resistance and tensile strength of thermoplastic elastomers.

[0046] In practice, the aluminum trichloride used may include anhydrous aluminum trichloride.

[0047] In addition, coupling agents may include silane coupling agents, such as γ-aminopropyltrimethoxysilane (KH550), which are compatible with components such as random copolymer polypropylene and polyolefin elastomers, thereby improving the impact resistance and tensile strength of thermoplastic elastomers.

[0048] In the embodiments of the present invention, unless otherwise specified, the solubilizers, coupling agents and other components used can be obtained by conventional methods in the art, such as being commercially available or self-made by conventional methods in the art.

[0049] This invention also provides a method for preparing the above-mentioned thermoplastic elastomer, comprising the following steps: mixing random copolymer polypropylene, solubilizer, coupling agent and polyolefin elastomer, and then sequentially performing intensive mixing and a first granulation to obtain the thermoplastic elastomer. This preparation process can produce a thermoplastic elastomer and improve its mechanical properties such as impact resistance and tensile strength.

[0050] Specifically, the intensive refining time can be 15 to 30 minutes, for example, 15 minutes, 18 minutes, 20 minutes, 23 minutes, 25 minutes, 28 minutes, 30 minutes or any combination thereof.

[0051] Specifically, in the above preparation process, a first granulator is used for the first granulation. The temperature of the first granulator can be 150-200℃, for example, 150℃, 160℃, 170℃, 180℃, 190℃, 200℃ or any combination thereof. The rotation speed can be 10-30Hz, for example, 10Hz, 13Hz, 15Hz, 18Hz, 20Hz or any combination thereof.

[0052] In practice, random copolymer polypropylene, solubilizer, coupling agent and polyolefin elastomer can be blended according to a preset ratio, then mixed in an internal mixer, and the resulting product is placed in a granulator for extrusion granulation (first granulation) to obtain thermoplastic elastomer.

[0053] In this embodiment of the invention, a conventional internal mixer can be used for internal mixing, and a conventional granulator can be used for granulation.

[0054] In this embodiment of the invention, polyolefin elastomers (such as butene-based elastomers) can be prepared by solution polymerization, which may specifically include batch polymerization and / or tubular polymerization.

[0055] In some embodiments, the preparation process of the polyolefin elastomer includes: polymerizing a first monomer raw material comprising ethylene and α-olefin under the action of a catalyst to obtain a polyolefin elastomer.

[0056] As mentioned above, α-olefins may include 1-butene.

[0057] As mentioned above, in the first monomer raw material used to polymerize and form random copolymer polypropylene, the mass ratio of ethylene to the first monomer raw material (i.e., the proportion of the mass of ethylene to the total mass of the first monomer raw material) can be greater than or equal to 2.5%, specifically 2.5% to 5%.

[0058] In addition, the above-mentioned catalysts may include Ziegler-Natta catalysts and / or metallocene catalysts, wherein the metallocene catalysts may include a main catalyst and a co-catalyst. The main catalyst may include a complex of a Group IVB transition metal and an alkylaluminoxane. The Group IVB transition metal may specifically include one or more of Ti, Zr, and Hf. The co-catalyst may include one or more of alkylaluminoxane, triisobutylaluminum, and organoboron compounds.

[0059] Specifically, the aforementioned alkylaluminoxanes may include methylaluminoxane (MAO).

[0060] For example, the main catalyst may include complexes of the aforementioned transition metals and MAO, such as one or more of the following: complexes of Ti and MAO, complexes of Zr and MAO, and complexes of Hf and MAO.

[0061] Furthermore, the above polymerization is carried out in a solvent, which may include alkane solvents, such as n-hexane and / or cyclohexane, and may use one alkane or a mixed alkane solvent of at least two alkanes.

[0062] Furthermore, the polymerization conditions can be: a polymerization temperature of 130–190°C, for example, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C or any combination thereof; a polymerization pressure of 4–8 MPa, for example, 4 MPa, 5 MPa, 6 MPa, 6.5 MPa, 7 MPa, 8 MPa or any combination thereof; and a polymerization time of 10–20 min, for example, 10 min, 13 min, 15 min, 18 min, 20 min or any combination thereof.

[0063] In general, during the preparation of the above-mentioned polyolefin elastomer, after the polymerization is completed, the obtained polymer product system can be subjected to flash evaporation devolatilization and second granulation (specifically extrusion granulation) to obtain the polyolefin elastomer.

[0064] Specifically, a second granulator can be used for the second granulation. The temperature of the second granulator can be 180–210°C, for example, 180°C, 190°C, 200°C, 210°C, or any combination thereof, and the rotation speed can be 10–30Hz, for example, 10Hz, 15Hz, 20Hz, 25Hz, 30Hz, or any combination thereof. In this embodiment of the invention, flash devolatilization can be performed using conventional methods in the art, and a conventional granulator in the art can be used for the second granulation; there are no particular limitations on this.

[0065] The present invention will be further described below through specific embodiments. In the following embodiments and comparative examples, unless otherwise specified, the PP-g-MAH used was purchased from DuPont, USA; the PE-g-MAH was purchased from Mitsui Chemicals, Japan; the HDI was purchased from Wanhua Chemical Group Co., Ltd.; the MDI was purchased from Huntsman Polyurethanes (China) Co., Ltd.; and the MMA-grafted PDMS was purchased from Hubei Xinqiao Biotechnology Co., Ltd.

[0066] Example 1:

[0067] 1. Preparation of butene-based elastomers

[0068] Ethylene and 1-butene were placed in n-hexane, and a metallocene catalyst was added. The polymerization reaction was carried out at 150 °C and 6.5 MPa for 12 min. Then, the obtained polymerization product system was subjected to flash evaporation and devolatilization and granulation to obtain butene-based elastomer.

[0069] The second granulator was used for granulation. The temperature of the second granulator was 190℃ and the rotation speed was 20Hz.

[0070] The metallocene catalyst consists of a main catalyst and a co-catalyst. The main catalyst is a complex of zirconium and methylaluminoxane, and the co-catalyst is methylaluminoxane.

[0071] 2. Preparation of thermoplastic elastomers

[0072] Step 1: Weigh 95 parts by weight of butene-based elastomer and degas it in a degassing chamber for 36 hours.

[0073] Step 2: By weight, 95 parts of degassed butene elastomer, 4 parts of random copolymer polypropylene, 0.5 parts of anhydrous aluminum trichloride, and 0.5 parts of KH550 are blended and placed in an internal mixer and mixed at 190°C for 20 minutes.

[0074] Step 3: Place the product obtained from the mixing in step 2 into a granulator and perform the first granulation at a temperature of 190℃ and a rotation speed of 20Hz to obtain a thermoplastic elastomer.

[0075] Examples 2 to 19, and Comparative Examples 1 to 3: The differences from Example 1 are as follows: the polyolefin elastomer and its content in the raw material composition, the type of polypropylene (random copolymer polypropylene or homopolymer polypropylene) and its content, the melt index of polypropylene, the density of polypropylene, the content of ethylene monomer units in random copolymer polypropylene, and the solubilizer and its content, coupling agent and its content in the raw material composition are different. See Tables 1 and 2 for details. Except for the differences shown in Tables 1 and 2, the other conditions are the same as in Example 1.

[0076] Comparative Example 4: The difference from Example 3 is that homopolymer polypropylene was used instead of random copolymer polypropylene. The melt index of the homopolymer polypropylene was 0.5 g / 10 min, and the density of the homopolymer polypropylene was 0.905 g / cm³. 3 See Tables 1 and 2 for details. Except for the differences shown in Tables 1 and 2, the other conditions are the same as in Example 3.

[0077] The thermoplastic elastomers prepared in each embodiment were analyzed by scanning electron microscopy (SEM). The results showed that the polyolefin elastomer, random copolymer polypropylene, and other components in the thermoplastic elastomer exhibited good compatibility. Taking Example 1 as an example... Figure 1 The image shows an SEM image of the thermoplastic elastomer prepared in Example 1. It can be seen that the components such as polyolefin elastomer and random copolymer polypropylene in the thermoplastic elastomer are well compatible.

[0078] In addition, the simply supported beam impact strength and tensile strength of the thermoplastic elastomers prepared in each embodiment and comparative example were measured (test methods refer to GB / T 18743.1-2022, GB / T 14272-2011), and the results are shown in Table 2.

[0079] Table 1

[0080]

[0081] Table 2

[0082]

[0083]

[0084] As can be seen from Table 2, compared with Comparative Examples 1 to 4, Examples 1 to 19, by using a raw material composition comprising 4 to 10 parts by weight of random copolymer polypropylene, 0.1 to 1 part by weight of solubilizer, 0.1 to 1 part by weight of coupling agent, and 88 to 95 parts by weight of polyolefin elastomer, can simultaneously improve the simply supported beam impact strength of the thermoplastic elastomer (not less than 9.3 kJ / m). 2 It improves the mechanical properties of thermoplastic elastomers by increasing tensile strength (not less than 23 MPa) and tensile strength.

[0085] Specifically, as seen in Examples 1-4, Comparative Examples 1 and 2, Comparative Example 1, without the addition of random copolymer polypropylene, exhibited low simply supported beam impact strength and tensile strength of the thermoplastic elastomer. In Comparative Example 2, the content of random copolymer polypropylene was too high, and the content of polyolefin elastomer was too low, resulting in a significant reduction in the simply supported beam impact strength of the thermoplastic elastomer. Compared to Comparative Examples 1 and 2, Examples 1-4, by introducing random copolymer polypropylene into the thermoplastic elastomer and controlling the content of random copolymer polypropylene within the range of 4-10 parts and the content of polyolefin elastomer within the range of 88-95 parts, significantly improved the simply supported beam impact strength of the thermoplastic elastomer while maintaining a high tensile strength, thus improving the mechanical properties of the thermoplastic elastomer.

[0086] Specifically, compared to Comparative Example 4 (which used homopolymer polypropylene), Example 3 uses random copolymer polypropylene, which can improve both the simply supported beam impact strength and tensile strength of the thermoplastic elastomer, and significantly improve the mechanical properties of the thermoplastic elastomer.

[0087] Furthermore, compared to Example 14 (which uses a polyolefin elastomer polymerized from 1-octene and ethylene), Example 3 uses a butene-based elastomer polymerized from 1-butene and ethylene, which can improve the tensile strength of the thermoplastic elastomer while maintaining the high impact strength of the simply supported beam, thus improving the mechanical properties of the thermoplastic elastomer.

[0088] Furthermore, compared to Example 13, in Examples 3 and 10 to 12, the mass percentage of random copolymer polypropylene is not less than 2.5%, which is beneficial to further improve the impact strength and tensile strength of the simply supported beam of the thermoplastic elastomer.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A thermoplastic elastomer, characterized in that, The thermoplastic elastomer is formed from a raw material composition comprising the following components in parts by weight: 4 to 10 parts random copolymer polypropylene, 0.1 to 1 part solubilizer, 0.1 to 1 part coupling agent, and 88 to 95 parts polyolefin elastomer.

2. The thermoplastic elastomer according to claim 1, characterized in that, The random copolymer polypropylene contains ethylene monomer units, and the mass percentage of the ethylene monomer units in the random copolymer polypropylene is greater than or equal to 2.5%. And / or, the melt index of random copolymer polypropylene is 0.1 to 1.5 g / 10 min; And / or, the density of the random copolymer polypropylene is 0.90–0.91 g / cm³. 3 .

3. The thermoplastic elastomer according to claim 1, characterized in that, The polyolefin elastomer is copolymerized from a second monomer raw material comprising ethylene and an α-olefin, wherein the α-olefin comprises 1-butene.

4. The thermoplastic elastomer according to claim 3, characterized in that, The polyolefin elastomer includes a butene-based elastomer copolymerized from ethylene and 1-butene; wherein, The butene-based elastomer has a melt flow rate of 0.5–5.0 g / 10 min at 190 °C and 2.16 kg. And / or, the mass percentage of 1-butene monomer units in the butene-based elastomer is greater than or equal to 15%; And / or, the density of the butene-based elastomer is 0.0862–0.885 g / cm³. 3 .

5. The thermoplastic elastomer according to claim 1, characterized in that, The solubilizer includes one or more of maleic anhydride-grafted polypropylene, maleic anhydride-grafted polyethylene, caprolactam diisocyanate, phenyl isocyanate, methyl methacrylate-grafted polydimethylsiloxane, and aluminum trichloride.

6. The thermoplastic elastomer according to any one of claims 1-5, characterized in that, The coupling agent includes a silane coupling agent, which includes γ-aminopropyltrimethoxysilane.

7. A method for preparing the thermoplastic elastomer according to any one of claims 1-6, characterized in that, Includes the following steps: The thermoplastic elastomer is prepared by mixing random copolymer polypropylene, solubilizer, coupling agent and polyolefin elastomer, followed by intensive mixing and first granulation.

8. The method for preparing the thermoplastic elastomer according to claim 7, characterized in that, The mixing time is 15-30 minutes; And / or, the first granulation is performed using a first granulator, wherein the temperature of the first granulator is 150-200°C and the rotation speed is 10-30Hz.

9. The method for preparing the thermoplastic elastomer according to claim 7 or 8, characterized in that, The preparation process of the polyolefin elastomer includes: polymerizing a first monomer raw material comprising ethylene and α-olefin under the action of a catalyst to obtain the polyolefin elastomer.

10. The method for preparing the thermoplastic elastomer according to claim 9, characterized in that, The α-olefin includes 1-butene; And / or, the catalyst comprises a Ziegler-Natta catalyst and / or a metallocene catalyst, preferably, the metallocene catalyst comprises a main catalyst and a co-catalyst, the main catalyst comprises a complex of a Group IVB transition metal and an alkylaluminoxane, and the co-catalyst comprises one or more of alkylaluminoxane, triisobutylaluminum, and organoboron compounds; And / or, the polymerization conditions are: polymerization temperature of 130–190°C, polymerization pressure of 4–8 MPa, and polymerization time of 10–20 min; and / or, the polymerization is carried out in a solvent, the solvent including alkane solvents.

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