Reversible cross-linked polyolefin network material and preparation method thereof
By introducing a diacrylate crosslinking agent with a β-hydroxy ester structure into polyolefins and blending it with a free radical initiator, reversible crosslinking was achieved, solving the problems of insufficient melt strength and creep resistance of polyolefin materials, and preparing remodelable high-performance materials.
Patent Information
- Application Number
- CN202411153232.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-21
- Publication Date
- 2026-03-03
AI Technical Summary
Polyolefin materials have poor melt strength and creep resistance due to the lack of cross-linked structure, and traditional modification methods are prone to producing irreversible cross-linked structures, resulting in difficult processing and poor remodeling.
By introducing a diacrylate crosslinking agent containing a β-hydroxy ester structure and blending it with polyolefins and free radical initiators, reversible crosslinking is achieved through autocatalysis, thus preparing a reversible crosslinked polyolefin network material.
The prepared reversible cross-linked polyolefin network material can be reshaped under hot pressing conditions, exhibiting excellent reshapeability and mechanical properties, and is suitable for large-scale industrial production.
Smart Images
Figure CN121591957A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of polymer materials technology, specifically relating to a reversible cross-linked polyolefin network material and its preparation method. Background Technology
[0002] Polyolefins refer to thermoplastic resin materials polymerized from ethylene, propylene, butene, or higher α-olefins, including polyethylene, polypropylene, ethylene-vinyl acetate copolymer, poly-1-butene, ethylene-acrylic acid copolymer, cyclic olefin polymers, etc. They are important polymer materials with large industrial demand and wide applications, finding extensive use in automotive parts, energy, medical equipment, pipes, and packaging. However, due to the lack of cross-linking structures, polyolefins have poor melt strength and creep resistance, limiting their applications.
[0003] Traditional methods have revealed ways to improve the creep resistance and other properties of polyolefins by introducing micro-crosslinked structures. However, these micro-crosslinked structures are not remodelable because they lack reversible bonds. Some reports have disclosed the simultaneous generation of β-hydroxy ester structures with autocatalytic activity during the formation of crosslinked structures through chemical modification. However, the reaction controllability is poor, and some irreversible crosslinked structures are easily generated, leading to difficulties in polyolefin processing and poor remodelability. Summary of the Invention
[0004] The purpose of this invention is to provide a reversible crosslinked polyolefin network material and its preparation method. The polyolefin crosslinked network obtained by this invention exhibits excellent remodeling performance due to the presence of a self-catalytic β-hydroxy ester structure. Moreover, the preparation method of this invention is simple to operate, easy to implement, and has good controllability. It can efficiently introduce β-hydroxy ester structures into polyolefins and is suitable for large-scale industrial production of reversible crosslinked polyolefin network materials.
[0005] The objective of this invention is achieved through the following technical solution:
[0006] In a first aspect, the present invention provides a reversible crosslinked polyolefin network material comprising the following raw material components: polyolefin, free radical initiator, and diacrylate crosslinking agent containing a β-hydroxy ester structure.
[0007] In some embodiments of the present invention, the polyolefin includes at least one of PP, PE, PB-1, POE, EPDM and their copolymers.
[0008] In some embodiments of the present invention, the diacrylate crosslinking agent containing a β-hydroxy ester structure includes at least one of dimethacrylate, 2-acrylate-2-hydroxy-1,3-propanediol, 1,2,3-butanetriol 1,3-diacrylate, 1,2,3,4-butanetetrol 2,3-diacrylate, 1,2,3,4-butanediol 1,3-diacrylate, and 1,4-butanediyldi[oxy(2-hydroxy-3,1-propanediyl)]diacrylate.
[0009] In some embodiments of the present invention, the amount of the diacrylate crosslinking agent containing a β-hydroxy ester structure in the raw material components can be adjusted according to the product performance requirements; for example, the amount of the diacrylate crosslinking agent containing a β-hydroxy ester structure can be adjusted according to the mechanical performance requirements of the product.
[0010] In some embodiments of the present invention, in the raw material components, based on 100 parts by weight of polyolefin, the weight of the diacrylate crosslinking agent containing the β-hydroxy ester structure is 0.1 to 10 parts, that is, the weight of the diacrylate crosslinking agent containing the β-hydroxy ester structure can be selected from 0.1 parts, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, and any value within the range of any two of the above values.
[0011] In some embodiments of the present invention, the free radical initiator is at least one selected from dicumyl peroxide, di(tert-butylperoxide)benzene, 2,5-dimethyl-2,5-di(tert-butylperoxide)hexane, and tert-butylperoxide.
[0012] In some embodiments of the present invention, in the raw material components, based on 100 parts by weight of polyolefin, the free radical initiator is 0.1 to 0.3 parts by weight, that is, the free radical initiator can be selected from 0.1 parts, 0.15 parts, 0.2 parts, 0.25 parts, 0.3 parts, and any value within the range of any two of the above values; preferably 0.15 to 0.2 parts.
[0013] In some embodiments of the present invention, the raw material components of the reversible crosslinked polyolefin network material further include antioxidants.
[0014] In some embodiments of the present invention, the antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, tris[2,4-di-tert-butylphenyl]phosphite, N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine, and 1,3,5-trimethyl-2,4,6-tris( At least one of 3,5-di-tert-butyl-4-hydroxybenzyl)benzene; preferably a complex of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris[2,4-di-tert-butylphenyl]phosphite; more preferably, the mass ratio of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] to tris[2,4-di-tert-butylphenyl]phosphite in the complex is 1:1 to 2:1.
[0015] In some embodiments of the present invention, in the raw material components, based on 100 parts by weight of polyolefin, the antioxidant is 0.1 to 0.3 parts by weight, that is, the antioxidant can be selected from 0.1 parts, 0.15 parts, 0.2 parts, 0.25 parts, 0.3 parts, and any value within the range of any two of the above values, preferably 0.12 to 0.2 parts by weight.
[0016] In some embodiments of the present invention, the reversible crosslinked polyolefin network material is obtained by blending raw material components including polyolefin, free radical initiator, diacrylate crosslinking agent containing β-hydroxy ester structure and optional antioxidant, followed by melt reaction extrusion granulation; preferably, the melt reaction temperature is 170-230°C, for example, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C, 230°C and any value within the range of any two of the above values, preferably 190-220°C.
[0017] The inventors discovered that when the melting reaction temperature is below 170°C, the melt viscosity is high, the components are not fully mixed, and the grafting rate of the diacrylate crosslinking agent containing the β-hydroxy ester structure on the polyolefin is low. Conversely, when the melting reaction temperature is above 230°C, the polyolefin raw material is easily degraded, resulting in a high melt index in the obtained reversible crosslinked polyolefin network material. However, melting the reaction within the range of 170–230°C ensures the acquisition of a reversible crosslinked polyolefin network material with good mechanical properties.
[0018] In some embodiments of the present invention, the reversible crosslinked polyolefin network material is obtained by blending polyolefin, free radical initiator, diacrylate crosslinking agent containing β-hydroxy ester structure and antioxidant, followed by melt reaction extrusion granulation.
[0019] In some embodiments of the present invention, the reversible cross-linked polyolefin network material can be reshaped at a hot-pressing temperature of 165–230°C.
[0020] In a second aspect, the present invention provides a method for preparing the reversible cross-linked polyolefin network material described in the first aspect, the method comprising:
[0021] (1) Mix the raw material components to obtain a premix.
[0022] (2) The reversible cross-linked polyolefin network material is obtained by melting, extruding and granulating the premix.
[0023] In some embodiments of the present invention, the mixing in step (1) is carried out in a high-speed mixer.
[0024] In some embodiments of the present invention, the mixing time in step (1) is 1 to 3 minutes.
[0025] In some embodiments of the present invention, the melting and extrusion operations in step (2) are performed using a twin-screw extruder.
[0026] In some embodiments of the present invention, the melting temperature in step (2) is 170-230°C, preferably 190-220°C.
[0027] The beneficial effects of this invention are as follows:
[0028] This invention proposes a reversible crosslinked polyolefin network material obtained by blending raw material components including polyolefin, free radical initiator, diacrylate crosslinking agent containing β-hydroxy ester structure and optional antioxidant, followed by melt reaction extrusion granulation. This reversible crosslinked polyolefin network material has a self-catalytic β-hydroxy ester structure, and under hot pressing conditions, the crosslinked network structure can be rearranged without the need for additional catalyst, exhibiting excellent remodeling properties.
[0029] This invention proposes a method for preparing reversibly crosslinked polyolefin network materials. This method utilizes a free radical initiator to initiate a crosslinking reaction between a diacrylate crosslinking agent containing a β-hydroxy ester structure and a polyolefin. This achieves the preparation of a reversibly crosslinked polyolefin network material with a self-catalytic β-hydroxy ester structure by directly introducing the β-hydroxy ester structure into the polyolefin. The method of this invention achieves a high success rate in introducing the β-hydroxy ester structure into the polyolefin, and the resulting reversibly crosslinked polyolefin network material exhibits excellent remodeling properties. Furthermore, the preparation method of this invention is easy to operate and implement, and is suitable for the large-scale industrial production of reversibly crosslinked polyolefin network materials. Attached Figure Description
[0030] Figure 1This is the infrared spectrum of the product from Example 1.
[0031] Figure 2 This is a schematic diagram of the remodeling performance of the reversible cross-linked polyolefin network material of Example 1, with a hot-pressing temperature of 180°C.
[0032] Figure 3 The figures show the grafting rate test results of glyceryl dimethacrylate in the reversible cross-linked polyolefin network materials of Examples 1, 5, and 7. The exothermic peak at 178°C in the figure is attributed to the reaction between glyceryl dimethacrylate and PP. The smaller the exothermic peak, the higher the grafting rate. Detailed Implementation
[0033] The following examples further illustrate the technology of the present invention. These examples are illustrative and exemplary of the present invention and do not limit the scope of the invention in any way.
[0034] Unless otherwise specified in the following examples, the conditions were performed under standard conditions or as recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products.
[0035] Example 1
[0036] Preparation of reversible cross-linked polyolefin network materials:
[0037] 100 parts by weight of PP (PPH-T03, Sinopec Zhenhai Refining & Chemical Company), 0.2 parts by weight of dicumyl peroxide, 3 parts by weight of glyceryl dimethacrylate, and 0.15 parts by weight of a complex of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris[2,4-di-tert-butylphenyl]phosphite (antioxidant 215) were mixed in a high-speed mixer for 2 min, then fed into a twin-screw extruder and extruded and granulated in a molten state at 210°C. The granules were then dried at 50°C to obtain a reversible crosslinked polyolefin network material. The infrared spectrum of this product is shown below. Figure 1 As shown in the diagram, the remodeling performance is illustrated below. Figure 2 As shown.
[0038] Example 2
[0039] Preparation of reversible cross-linked polyolefin network materials:
[0040] 100 parts by weight of PE (DFDA7042, Sinopec Zhenhai Refining & Chemical Branch), 0.1 parts of di(tert-butylperoxyisopropyl) ester, 0.1 parts of 2-hydroxy-1,3-propanediol 2-acrylate, and 0.1 parts of a complex of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris[2,4-di-tert-butylphenyl]phosphite (antioxidant 225) were mixed in a high-speed mixer for 1 min, then fed into a twin-screw extruder and extruded and granulated in a molten state at 170°C, and then dried at 50°C to obtain a reversible cross-linked polyolefin network material.
[0041] Example 3
[0042] Preparation of reversible cross-linked polyolefin network materials:
[0043] 100 parts by weight of PB-1 (99.2% isotacticity, melt index 1.7 g / 10 min at 230℃ and 2.16 kg load, Sinopec Zhenhai Refining & Chemical Branch), 0.3 parts by weight of 2,5-dimethyl-2,5-di(tert-butylperoxide)hexane, 5 parts by weight of glyceryl dimethacrylate, 5 parts by weight of 2-hydroxy-1,3-propanediol 2-acrylate, and 0.3 parts by weight of octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate were mixed in a high-speed mixer for 3 min, then fed into a twin-screw extruder and extruded and granulated in a molten state at 230℃, and then dried at 50℃ to obtain a reversible cross-linked polyolefin network material.
[0044] Example 4
[0045] The preparation method of the reversible cross-linked polyolefin network material is the same as in Example 1, except that the amount of dicumyl peroxide added is 0.3 parts.
[0046] Example 5
[0047] The preparation method of the reversible cross-linked polyolefin network material is the same as in Example 1, except that the amount of dicumyl peroxide added is 0.1 parts.
[0048] Example 6
[0049] The preparation method of the reversible cross-linked polyolefin network material is the same as in Example 1, except that it is extruded and granulated in a molten state at 230°C.
[0050] Example 7
[0051] The preparation method of the reversible cross-linked polyolefin network material is the same as in Example 1, except that it is extruded and granulated in a molten state at 180°C.
[0052] Test Example 1
[0053] The remodeling performance of the reversible cross-linked polyolefin network materials obtained in Examples 1-3 was tested. The test method was as follows: the reversible cross-linked polyolefin network materials were cut into particles using a pelletizer, and then hot-pressed using a flat vulcanizing machine to determine their remodeling performance. The results are shown in Table 1.
[0054] Table 1. Product Remodeling Performance Test Results
[0055] serial number Remodeling the sample surface Example 1 smooth Example 2 smooth Example 3 smooth
[0056] Test Example 2
[0057] The melt flow index of the reversible cross-linked polyolefin network materials obtained in Examples 1, 4, and 6 was tested under the following conditions: 230℃ and 2.16 kg. The results are shown in Table 2.
[0058] Table 2 Melt Flow Index Test Results
[0059] serial number Melt index (g / 10min) Example 1 3.2 Example 4 3.9 Example 6 3.5
[0060] Test Example 3
[0061] The grafting rate of dimethacrylate in the reversible cross-linked polyolefin network materials obtained in Examples 1, 5, and 7 was tested by DSC, and the results are as follows: Figure 3 As shown.
[0062] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to embodiments, but it should be understood that the terms used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications having the same function.
Claims
1. A reversible cross-linked polyolefin network material, characterized in that, It includes the following raw material components: polyolefin, free radical initiator, and diacrylate crosslinking agent containing β-hydroxy ester structure.
2. The reversible cross-linked polyolefin network material according to claim 1, characterized in that, The polyolefin includes at least one of PP, PE, PB-1, POE, EPDM and their copolymers.
3. The reversible cross-linked polyolefin network material according to claim 1 or 2, characterized in that, The β-hydroxy ester-containing diacrylate crosslinking agent includes at least one of the following: glyceryl dimethacrylate, 2-acrylate-2-hydroxy-1,3-propanediol, 1,2,3-butanetriol 1,3-diacrylate, 1,2,3,4-butanetetrol 2,3-diacrylate, 1,2,3,4-butanediol 1,3-diacrylate, and 1,4-butanediyldi[oxy(2-hydroxy-3,1-propanediyl)]diacrylate.
4. The reversible cross-linked polyolefin network material according to any one of claims 1 to 3, characterized in that, In the raw material components, based on 100 parts by weight of polyolefin, the weight of the diacrylate crosslinking agent containing β-hydroxy ester structure is 0.1 to 10 parts by weight.
5. The reversible cross-linked polyolefin network material according to any one of claims 1 to 4, characterized in that, The free radical initiator is at least one of dicumyl peroxide, di(tert-butylperoxide)benzene, 2,5-dimethyl-2,5-di(tert-butylperoxide)hexane, and tert-butylperoxide.
6. The reversible cross-linked polyolefin network material according to any one of claims 1 to 5, characterized in that, In the raw material components, based on 100 parts by weight of polyolefin, the free radical initiator is 0.1 to 0.3 parts by weight, preferably 0.15 to 0.2 parts by weight.
7. The reversible cross-linked polyolefin network material according to any one of claims 1 to 6, characterized in that, The raw material components of the reversible crosslinked polyolefin network material further include antioxidants; preferably, the antioxidants are pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, tris[2,4-di-tert-butylphenyl]phosphite, N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine, and 1,3,5-trimethyl- At least one of 2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene; preferably a complex of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris[2,4-di-tert-butylphenyl]phosphite; more preferably, the mass ratio of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] to tris[2,4-di-tert-butylphenyl]phosphite in the complex is 1:1 to 2:
1.
8. The reversible cross-linked polyolefin network material according to claim 7, characterized in that, In the raw material components, based on 100 parts by weight of polyolefin, the antioxidant is 0.1 to 0.3 parts by weight, preferably 0.12 to 0.2 parts by weight.
9. The reversible cross-linked polyolefin network material according to any one of claims 1 to 8, characterized in that, The reversible crosslinked polyolefin network material is obtained by blending raw material components including polyolefin, free radical initiator, diacrylate crosslinking agent containing β-hydroxy ester structure and optional antioxidant, followed by melt reaction extrusion granulation; preferably, the melt reaction temperature is 170-230℃, more preferably 190-220℃.
10. A method for preparing the reversible cross-linked polyolefin network material according to any one of claims 1 to 9, characterized in that, The preparation method includes: (1) Mix the raw material components to obtain a premix; preferably, the mixing time is 1 to 3 minutes; (2) The reversible cross-linked polyolefin network material is obtained by melting, extruding and granulating the premixed material; preferably, the melting temperature is 170-230℃, and more preferably 190-220℃.