Polyolefin composition as well as preparation method and application thereof

Abstract

The invention discloses a polyolefin composition as well as a preparation method and application thereof. The polyolefin comprises the following components in parts by weight: 5-15 parts of polyethylene; 13 to 27 parts of an ethylene-vinyl acetate copolymer; 10 to 20 parts of POE (Polyolefin Elastomer); 3-8 parts of a compatilizer; 80 to 120 parts of magnesium hydroxide; 0.3 to 3.5 parts of a silane coupling agent; wherein the silane coupling agent comprises a long-chain alkyl silane coupling agent, and the number of carbon atoms of long-chain alkyl is larger than or equal to 7. According to the invention, magnesium hydroxide is added into a polyolefin resin system as a flame retardant, and the long-chain alkyl silane coupling agent is added, so that the prepared polyolefin composition has better flame retardant property and better mechanical property and processability at the same time.

Description

Technical Field

[0001] This invention belongs to the field of halogen-free flame retardant technology, specifically relating to a polyolefin composition, its preparation method, and its application. Background Technology

[0002] With rapid economic development, national policies are paying increasing attention to fire safety, and there are higher requirements for the heat release and smoke release performance of insulation materials. In the event of a fire, cables used for power, lighting and communication need to be able to operate normally, prevent chain combustion, and release less toxic smoke in order to buy time for fire rescue.

[0003] To meet the requirements of low smoke, halogen-free, and high flame retardant properties, low smoke, halogen-free polyolefin insulation materials usually require the addition of a large amount of hydroxide flame retardant. The addition of a large amount of flame retardant will lead to a decrease in the mechanical properties and processing properties of the system (slower extrusion speed, affecting efficiency), and the elongation at break after cross-linking of the polyolefin system will also decrease. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings or defects of existing low-smoke halogen-free flame-retardant polyolefin compositions that cannot simultaneously possess high flame retardant properties, mechanical properties, and processing properties, and to provide a polyolefin composition.

[0005] Another object of the present invention is to provide a method for preparing the polyolefin composition.

[0006] Another object of the present invention is to provide the application of the polyolefin composition.

[0007] To achieve the above objectives, the present invention employs the following technical solution: A polyolefin composition comprising the following components in parts by weight: 5-15 parts of polyethylene; 13-27 parts of ethylene-vinyl acetate copolymer; POE 10~20 copies; 3-8 parts compatibilizer; 80-120 parts of magnesium hydroxide; 0.3-3.5 parts of silane coupling agent; The silane coupling agent includes a long-chain alkyl silane coupling agent, wherein the long-chain alkyl group has ≥7 carbon atoms.

[0008] This invention provides a polyolefin composition in which magnesium hydroxide is added as a flame retardant to a polyolefin resin (polyethylene, ethylene-vinyl acetate copolymer and POE) system, and a long-chain alkyl silane coupling agent is added. This can significantly improve the compatibility between the flame retardant and the resin system. Moreover, the long-chain alkyl has flexibility and can play an internal lubricating role, reducing the internal friction of the system. This allows for the achievement of high flame retardant performance without reducing processing performance and mechanical properties.

[0009] It should be noted that the number of carbon atoms in the long-chain alkyl group described in this invention is, for example, but not limited to, ≥7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17 or 18, and the specific values ​​between the above values ​​are not exhaustively listed in this invention due to space limitations and for the sake of brevity.

[0010] Furthermore, the long-chain alkylsilane coupling agent has the structural formula R1-Si-X1(X2)(X3), wherein R1 includes octyl, dodecyl, hexadecyl or octadecyl; X1 includes methoxy and / or ethoxy; X2 includes methoxy and / or ethoxy; and X3 includes methoxy and / or ethoxy.

[0011] Specifically, the long-chain alkylsilane coupling agent includes one or more of octyltrimethoxysilane, octyltriethoxysilane, dodecyltrimethoxysilane, dodecyltriethoxysilane, hexadecyltrimethoxysilane, hexadecyltriethoxysilane, octadecyltrimethoxysilane, octadecyltriethoxysilane, octadecyltriethoxysilane, octadecylmethyldimethoxysilane, or octadecylmethyldiethoxysilane.

[0012] Furthermore, the long-chain alkyl group has ≥8 carbon atoms.

[0013] Furthermore, the long-chain alkyl alkyl group in the long-chain alkyl silane coupling agent has 12 to 18 carbon atoms.

[0014] It should be noted that, in the polyolefin composition of the present invention, the total content of polyethylene, vinyl acetate copolymer and POE is preferably not less than 20 wt%.

[0015] It should be noted that the silane coupling agent described in this invention is 0.3 to 3.5 parts, for example, but not limited to 0.3 parts, 0.5 parts, 0.8 parts, 1 part, 1.2 parts, 1.5 parts, 1.8 parts, 2 parts, 2.2 parts, 2.5 parts, 2.8 parts, 3 parts, 3.2 parts, or 3.5 parts, etc., and the specific values ​​between the above-mentioned values ​​are not exhaustively listed in this invention due to space limitations and for the sake of brevity.

[0016] Furthermore, the silane coupling agent also includes an aminosilane coupling agent. Adding an aminosilane coupling agent to the system can further improve the compatibility between magnesium hydroxide and the resin system, while the formation of hydrogen bonds between the amino groups further improves the mechanical properties.

[0017] Further, the aminosilane coupling agent has the structural formula R2-Si-Y1(Y2)(Y3), wherein R2 includes γ-aminopropyl, N-phenyl-γ-aminopropyl, N-(n-butyl)-γ-aminopropyl, N-β-(aminoethyl)-aminopropyl or N,N-diethyl-3-aminopropyl; Y1 includes methoxy and / or ethoxy; Y2 includes methoxy and / or ethoxy; and Y3 includes methoxy and / or ethoxy.

[0018] Further, the aminosilane coupling agent includes one or more of γ-aminopropyltriethoxysilane, NN-diethylaminopropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropylmethyldiethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N-(n-butyl)-γ-aminopropyltrimethoxysilane, or N-β-(aminoethyl)-aminopropyltriethoxysilane.

[0019] In some preferred embodiments, the mass ratio of the long-chain alkylsilane coupling agent to the aminosilane coupling agent in the silane coupling agent is not less than 1:1. For example, but not limited to, ratios of not less than 1:1, 1.2:1, 1.5:1, 1.8:1, 2:1, 2.2:1, 2.5:1, 2.8:1, 3:1, 3.2:1, or 3.5:1, etc.

[0020] Furthermore, the mass ratio of long-chain alkylsilane coupling agent to aminosilane coupling agent in the silane coupling agent is (1.5~3):1.

[0021] Furthermore, in the polyolefin composition of the present invention, the content of the silane coupling agent is preferably 0.3~2wt%; more preferably 0.5~1.5wt%.

[0022] Furthermore, the D50 of the magnesium hydroxide is 0.8~3.5μm.

[0023] Specifically, the D50 is tested using a laser tester.

[0024] Furthermore, the mass ratio of polyethylene, ethylene-vinyl acetate copolymer and POE is 1:(1~5):(1~4).

[0025] Furthermore, the polyethylene has a melt flow rate of 0.5~10g / 10min at 190℃ and 2.16kg.

[0026] Specifically, the test standard for the melt flow rate of the polyethylene is ASTM D-1238-2010.

[0027] Furthermore, the polyethylene includes linear low-density polyethylene.

[0028] Furthermore, the ethylene-vinyl acetate copolymer has a melt flow rate of 1~8 g / min at 190°C and 2.16 kg.

[0029] Specifically, the test standard for the melt flow rate of the ethylene-vinyl acetate copolymer is ASTM D-1238-2010.

[0030] Furthermore, the vinyl acetate content of the ethylene-vinyl acetate copolymer is 13~35wt%.

[0031] Furthermore, the POE includes ethylene-octene copolymer and / or ethylene-butene copolymer.

[0032] Furthermore, the POE has a melt flow rate of 1~8 g / min at 190°C and 2.16 kg.

[0033] Specifically, the test standard for the melt flow rate of the POE is ASTM D-1238-2010.

[0034] Furthermore, the compatibilizer comprises polyolefin grafted maleic anhydride.

[0035] Furthermore, the compatibilizer is polyethylene grafted with maleic anhydride and / or POE grafted with maleic anhydride.

[0036] In some preferred embodiments, the grafting rate of maleic anhydride in the compatibilizer is 0.5~2wt%.

[0037] Specifically, the method for testing the grafting rate of maleic anhydride is acid-base titration.

[0038] Furthermore, without affecting the flame retardant properties, mechanical properties, and processing properties of the polyolefin composition of the present invention, the polyolefin composition of the present invention further includes 0.1 to 5 parts of processing aids, such as, but not limited to, 0.05 to 2 parts of antioxidants and 0.05 to 3 parts of lubricants.

[0039] Furthermore, the antioxidants include, but are not limited to, one or more of hindered phenolic antioxidants, phosphite antioxidants, or thioester antioxidants.

[0040] Specifically, the hindered phenolic antioxidants are N,N'-hexamethylene bis(3,5-di-tert-butyl-4-hydroxyphenylpropionamide) (Irganox 1098), pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (Irganox 1010), 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione (antioxidant 1790), 1,6-hexanediol bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (Irganox 259), and octadecyl β-(4-hydroxy-3,5-di-tert-butylphenyl)propionate (Irganox 1098). 1076) or one or more of 3,9-bis{2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)acrylic acid]-1,1-dimethyl}-2,4,8,10-tetraoxaspirocycloundecane (ADK AO-80).

[0041] The phosphite antioxidant is one or more of tris(2,4-di-tert-butylphenyl) phosphite (antioxidant 168), bis(2,6-di-tert-butyl-4-tolyl) pentaerythritol phosphite (PEP-36), or 627A.

[0042] The thioester antioxidant is one or more of the following: distearate thiodipropionate, dodecyl thiodipropionate (antioxidant DLTDP), dilaurate thiodipropionate, or pentaerythritol-based dodecyl thiopropionate.

[0043] Furthermore, the lubricant can be a silicone lubricant.

[0044] This invention also protects a method for preparing the above-mentioned polyolefin composition, comprising the following steps: The components are mixed evenly in proportion to obtain a premix, and the premix is ​​then subjected to intensive mixing and extrusion granulation to obtain a polyolefin composition.

[0045] Preferably, the preparation method includes the following steps: S1. Modified magnesium hydroxide is obtained by coating magnesium hydroxide with a silane coupling agent; S2. Modified magnesium hydroxide and other components are mixed evenly in proportion to obtain a premix. The premix is ​​then subjected to intensive mixing and extrusion granulation to obtain a polyolefin composition.

[0046] In some preferred embodiments, step S1 specifically includes: Magnesium hydroxide was added to anhydrous ethanol and dispersed by ultrasonic stirring; then a silane coupling agent was added, and the pH of the system was adjusted to 5-6. The mixture was stirred at 75-85℃ for 4-8 hours, filtered, and dried to obtain modified magnesium hydroxide.

[0047] Furthermore, the mixing speed in step S2 is 1500~2000 rpm.

[0048] Furthermore, the mixing temperature in step S2 is 120~140℃.

[0049] Furthermore, the extrusion temperature in step S2 is 130~155℃.

[0050] The present invention also protects the use of the above-mentioned polyolefin composition in the preparation of cable materials.

[0051] A cable material is prepared using the above-mentioned polyolefin composition.

[0052] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a polyolefin composition. By adding magnesium hydroxide as a flame retardant and a long-chain alkylsilane coupling agent to a polyolefin resin system, the resulting polyolefin composition can have good flame retardant properties while also having good mechanical and processing properties. Detailed Implementation

[0053] The present invention will be further described in detail below with reference to specific embodiments. These embodiments are only used to explain the present invention and are not intended to limit the scope of the present invention. Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods; the materials and reagents used are commercially available unless otherwise specified.

[0054] 1. Raw materials used in each embodiment and comparative example: Polyolefin resin: Linear low-density polyethylene (LLDPE): LLDPE EXCEED 3518CB, with a melt flow rate of 3.5 g / 10 min at 190°C and 2.16 kg, purchased from ExxonMobil; Ethylene-vinyl acetate copolymer (EVA): EVA 6020M, with a melt flow rate of 6 g / 10 min at 190 °C and 2.16 kg, purchased from Yangzi Petrochemical-BASF; POE: POE 58750, with a melt flow rate of 5 g / 10 min at 190 °C and 2.16 kg, purchased from Dow Chemical. Compatibilizer: Polyethylene grafted with maleic anhydride, MC-218, purchased from Nengzhiguang; Magnesium hydroxide: Magnesium hydroxide 1:H-5, D50 1.8μm, was purchased from Qiu Bo, USA; Magnesium hydroxide 2: Vertex 100, D50 1.5μm, purchased from Qiu Bo, USA; Aluminum hydroxide: OL-104LEO, D50 2.0μm, purchased from Chow Bosch, USA; Silane coupling agents: Long-chain alkylsilane coupling agent 1: hexadecyltrimethoxysilane, FD-580, CAS: 16415-12-6, purchased from Boiling Point Chemicals; Long-chain alkylsilane coupling agent 2: Octadecyltrimethoxysilane, FD-586, CAS: 3069-42-9, purchased from Boiling Point Chemicals; Long-chain alkyl silane coupling agent 3: Octyltriethoxysilane, FD-350, CAS: 2943-75-1, purchased from Boiling Point Chemicals; Aminosilane coupling agent 1: NN diethylaminopropyltrimethoxysilane, FD-703, CAS: 41051-80-3, purchased from Boiling Point Chemical. Aminosilane coupling agent 2: γ-aminopropyltriethoxysilane, FD-550, CAS: 919-30-2, purchased from Boiling Point Chemicals; Vinylsilane coupling agent: Vinyltriethoxysilane, FD-151, CAS: 78-08-0, purchased from Boiling Point Chemicals; Short-chain alkyl silane coupling agent: propyltrimethoxysilane, FD-380, CAS: 1067-25-0, purchased from Boiling Point Chemicals; Processing aids: Antioxidant: Antioxidant 1010, commercially available; It should be noted that the parallel experiments in the examples and comparative examples all used raw materials from the same source.

[0055] 2. The polyolefin compositions of Examples 1-8 and the comparative examples were prepared according to the formulations in Tables 1-2 and the following preparation method: S1. Add 100g of magnesium hydroxide / aluminum hydroxide to 500~1000mL of anhydrous ethanol, and ultrasonically stir for 0.5~2 hours to disperse until uniform; then add silane coupling agent and dilute acid to adjust the pH of the system to 5.5~7.0, stir at 80℃ for 6 hours, filter, and dry at 80℃ for 8 hours to obtain modified magnesium hydroxide / aluminum hydroxide. S2. The modified magnesium hydroxide / aluminum hydroxide, polyolefin, compatibilizer, and processing aid components described in step S1 are added to a high-speed mixer and mixed evenly at a speed of 1500~2000 rpm to obtain a premix. The premix is ​​then fed into an internal mixer and granulated by extrusion through a two-stage single-screw extruder to obtain a polyolefin composition. The internal mixing temperature is 120~140℃, and the extrusion temperature is 130~155℃.

[0056] The polyolefin composition described in Example 9 was prepared by the following method: Each component is fed into a high-speed mixer and mixed evenly at a speed of 1500~2000 rpm to obtain a premix. The premix is ​​fed into an internal mixer and then extruded and granulated through a two-stage single-screw extruder to obtain a polyolefin composition. The internal mixing temperature is 120~140℃, and the extrusion temperature is 130~155℃.

[0057] 3. Performance Testing: (1) Mechanical and flame retardant performance tests: The polyolefin compositions prepared in each example and comparative example were pressed into sheets at 180℃ for 10 min on a flat vulcanizing machine with a pressure of 15 MPa. The sheet thicknesses were 1 mm and 3 mm. After being placed at room temperature for 16 h, the 1 mm thick sheet was irradiated and crosslinked (irradiation dose of 8 Mrad). The mechanical properties were then tested according to standard GB / T 1040.2-2006. GB / T32129-2015 stipulates that the tensile strength after irradiation and crosslinking should be ≥10 MPa and the elongation at break should be ≥150%. The 3mm thick sample was cut into 100*100*3mm strips, and the heat release was tested according to the standard ISO5660-2015, with a heat flux of 50 KW; applications typically require a peak heat release rate of <115kW / m². 2 ; (2) Processing performance test: 1 kg of the polyolefin composition prepared in each example and comparative example was extruded using a Hap rheometer at a temperature of 160℃ and a rotation speed of 60 rpm. The extrusion was continuous, and stable torque data was recorded. The larger the torque, the higher the extrusion temperature rise and the worse the processing performance. The application usually requires a torque of <125 N*m.

[0058] Examples 1-9 and Comparative Examples 1-3 Table 1. Amounts (parts by weight) and properties of each component in the polyolefin compositions of Examples 1-9

[0059] Table 2. Amounts (parts by weight) and properties of each component in the polyolefin compositions of each comparative example.

[0060] As can be seen from Table 1, the polyolefin composition prepared by this invention possesses high flame retardant properties, mechanical properties, and processing properties. Specifically, the tensile strength after crosslinking is ≥10 MPa, the elongation at break is ≥150%, and the peak heat release is <115 kW / m. 2 Torque <125N*m.

[0061] As can be seen from Comparative Examples 1 and 2, if other silane coupling agents are used instead of the long-chain alkylsilane coupling agent in this invention, the performance of the resulting polyolefin composition will be significantly reduced, the heat release peak will not meet the application requirements, and the torque will increase significantly.

[0062] As can be seen from Comparative Example 3, although the polyolefin composition prepared by using other hydroxides instead of magnesium hydroxide in this invention has better processing performance, its flame retardant performance is significantly reduced.

[0063] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A polyolefin composition, characterized in that, Includes the following components, calculated in parts by weight: 5-15 parts of polyethylene; 13-27 parts of ethylene-vinyl acetate copolymer; POE 10~20 copies; 3-8 parts compatibilizer; 80-120 parts of magnesium hydroxide; 0.3-3.5 parts of silane coupling agent; The silane coupling agent includes a long-chain alkyl silane coupling agent, wherein the long-chain alkyl group has ≥7 carbon atoms; preferably, the long-chain alkyl group has ≥8 carbon atoms; more preferably, the long-chain alkyl group has 12 to 18 carbon atoms.

2. The polyolefin composition according to claim 1, characterized in that, The silane coupling agent also includes an aminosilane coupling agent.

3. The polyolefin composition according to claim 2, characterized in that, The mass ratio of long-chain alkylsilane coupling agent to aminosilane coupling agent in the silane coupling agent is not less than 1:1; preferably, the mass ratio of long-chain alkylsilane coupling agent to aminosilane coupling agent in the silane coupling agent is (1.5~3):

1.

4. The polyolefin composition according to claim 1, characterized in that, The mass ratio of the polyethylene, ethylene-vinyl acetate copolymer and POE is 1:(1~5):(1~4).

5. The polyolefin composition according to claim 1, characterized in that, The magnesium hydroxide has a D50 of 0.8~3.5μm.

6. The polyolefin composition according to claim 1, characterized in that, The compatibilizer comprises polyolefin-grafted maleic anhydride; preferably, the compatibilizer is polyethylene-grafted maleic anhydride and / or POE-grafted maleic anhydride.

7. The polyolefin composition according to claim 1, characterized in that, It also includes 0.1 to 5 parts of processing aids.

8. A method for preparing the polyolefin composition according to any one of claims 1 to 7, characterized in that, Includes the following steps: The components are mixed evenly in proportion to obtain a premix, and the premix is ​​then subjected to intensive mixing and extrusion granulation to obtain a polyolefin composition. Preferably, the preparation method includes the following steps: S1. Modified magnesium hydroxide is obtained by coating magnesium hydroxide with a silane coupling agent; S2. Modified magnesium hydroxide and other components are mixed evenly in proportion to obtain a premix. The premix is ​​then subjected to intensive mixing and extrusion granulation to obtain a polyolefin composition.

9. The use of the polyolefin composition according to any one of claims 1 to 7 in the preparation of cable materials.

10. A cable material, characterized in that, It is prepared using the polyolefin composition according to any one of claims 1 to 7.

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