Flame-retardant polyethylene cable material for ships and preparation method thereof

Abstract

The invention relates to the technical field of cables, and provides a flame-retardant polyethylene cable material for ships and a preparation method of the flame-retardant polyethylene cable material. The flame-retardant polyethylene cable material for ships comprises the following raw materials in parts by weight: 65-75 parts of polyethylene, 15-20 parts of an ethylene-vinyl acetate copolymer, 20-24 parts of a polyolefin elastomer, 10-15 parts of a flame retardant, 5-7 parts of a compatilizer and 2-3 parts of an antioxidant, the flame retardant is composite zinc borate and metal hydroxide; the preparation method of the composite zinc borate comprises the following steps: adding ferric tartrate and ferric citrate into water, adding zinc borate, stirring, concentrating and drying to obtain the composite zinc borate. According to the technical scheme, the problem of poor flame retardance of the polyethylene cable material for the ship in the related technology is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of cables, and in particular to a flame-retardant polyethylene cable material for ships and a preparation method thereof. Background Art

[0002] Zinc borate, a commonly used inorganic flame retardant synergist in flame-retardant polyethylene cable materials for marine applications, can enhance flame retardancy through mechanisms such as charring and heat absorption. However, as a typical inorganic filler, zinc borate has inherent compatibility limitations with non-polar matrices like polyethylene. Its surface polar groups easily lead to particle agglomeration, causing internal stress concentration in the material, limiting its flame retardancy. Furthermore, zinc borate's low efficiency in promoting charring prevents it from effectively suppressing the thermal decomposition chain reaction triggered by high temperatures, resulting in poor flame retardancy.

[0003] In summary, it is of vital importance to overcome the problem of insufficient flame retardant efficiency of zinc borate in polyethylene cable materials and develop a polyethylene cable material for ships with improved flame retardancy. Summary of the Invention

[0004] The present invention provides a flame-retardant polyethylene cable material for ships and a preparation method thereof, which solves the problem of poor flame retardancy of polyethylene cable materials for ships in the related art.

[0005] The technical solutions of the present invention are as follows: The present invention provides a flame-retardant polyethylene cable material for ships, wherein the raw materials include the following components in parts by weight: 65-75 parts of polyethylene, 15-20 parts of ethylene-vinyl acetate copolymer, 20-24 parts of polyolefin elastomer, 10-15 parts of flame retardant, 5-7 parts of compatibilizer, and 2-3 parts of antioxidant; The flame retardant is a composite of zinc borate and metal hydroxide; The preparation method of the composite zinc borate comprises the following steps: Ferric tartrate and ferric citrate are added into water, zinc borate is added, the mixture is stirred, concentrated and dried to obtain the composite zinc borate.

[0006] As a further technical solution, the mass volume ratio of the zinc borate to water is 1g:20~30mL.

[0007] In the flame-retardant polyethylene cable material for ships of the present invention, the polyolefin elastomer gives it good elasticity and flexibility. In its microstructure, different performance requirements are met by adjusting the crystallinity and molecular chain structure. When subjected to external force, the polyolefin elastomer can undergo elastic deformation, absorb energy, and protect the cable material from damage.

[0008] In the flame-retardant polyethylene cable material for ships of the present invention, the antioxidant can capture free radicals generated during the oxidation process of the polymer material, convert the highly active free radicals into relatively stable substances, and thus interrupt the oxidation chain reaction.

[0009] As a further technical solution, the mass ratio of the ferric tartrate, ferric citrate and zinc borate is 2~3:4:9.

[0010] In the flame-retardant polyethylene cable material for ships of the present invention, the mass ratio of ferric tartrate, ferric citrate and zinc borate can be 2:4:9, 2.1:4:9, 2.2:4:9, 2.3:4:9, 2.4:4:9, 2.5:4:9, 2.6:4:9, 2.7:4:9, 2.8:4:9, 2.9:4:9, 3:4:9, and preferably 3:4:9.

[0011] In the flame-retardant polyethylene cable material for ships of the present invention, when ferric tartrate, ferric citrate and zinc borate are mixed in a mass ratio of 2-3:4:9, the catalytic carbonization effects of ferric tartrate and ferric citrate are synergistically enhanced. The reasonable ratio of ferric tartrate and ferric citrate enables the catalytic carbonization reaction to proceed in an orderly manner at different stages. The generated carbon layer is denser, continuous and has higher strength, can more effectively prevent the diffusion of oxygen and other combustible gases, and inhibit the further development of the combustion reaction, thereby significantly improving the flame retardant properties of the cable material.

[0012] As a further technical solution, the mass ratio of the composite zinc borate to the metal hydroxide is 1:3-4; The metal hydroxide includes one or both of magnesium hydroxide and aluminum hydroxide.

[0013] The flame-retardant polyethylene cable material for ships of the present invention comprises one or both of magnesium hydroxide and aluminum hydroxide as the metal hydroxide, ensuring the flame retardant properties of the flame-retardant polyethylene cable material for ships. During ship operation, cables may catch fire due to electrical failures, overloads, and other factors. The excellent flame retardant properties of magnesium hydroxide or aluminum hydroxide can effectively prevent the spread of fire, ensuring the safety of the ship and personnel.

[0014] As a further technical solution, the stirring speed is 300-400 rpm, the temperature is 60-70° C., and the time is 45-60 min.

[0015] As a further technical solution, the ethylene-vinyl acetate copolymer includes a first ethylene-vinyl acetate copolymer and a second ethylene-vinyl acetate copolymer; The mass fraction of vinyl acetate in the first ethylene-vinyl acetate copolymer is 30% to 35%; The mass fraction of vinyl acetate in the second ethylene-vinyl acetate copolymer is 10% to 15%.

[0016] The present invention innovatively selects a first ethylene-vinyl acetate copolymer with a vinyl acetate mass fraction of 30% to 35% and a second ethylene-vinyl acetate copolymer with a vinyl acetate mass fraction of 10% to 15%, thereby improving the tensile strength of the flame-retardant polyethylene cable material for ships. The first ethylene-vinyl acetate copolymer has a high vinyl acetate content and fully exerts its good flexibility and compatibility in the cable material system. The vinyl acetate groups on its molecular chain interact with the molecular chains of other components such as polyethylene and polyolefin elastomers, closely connecting the components and achieving uniform dispersion. The second ethylene-vinyl acetate copolymer has a relatively low vinyl acetate content and has a high crystallinity and rigidity. Inside the cable material, it fills between other polymer molecular chains to form physical crosslinking points, effectively limiting the relative sliding of the molecular chains and greatly enhancing the stability of the internal structure of the material. Therefore, the present invention uses two ethylene-vinyl acetate copolymers with different vinyl acetate mass fractions to compound and improve the tensile strength of the flame-retardant polyethylene cable material for ships.

[0017] As a further technical solution, the mass ratio of the first ethylene-vinyl acetate copolymer to the second ethylene-vinyl acetate copolymer is 3-6:1.

[0018] In the flame-retardant polyethylene cable material for ships of the present invention, when the mass ratio of the first ethylene-vinyl acetate copolymer to the second ethylene-vinyl acetate copolymer is 3 to 6:1, the tensile strength of the flame-retardant polyethylene cable material for ships is further improved.

[0019] As a further technical solution, the compatibilizer includes one of maleic anhydride grafted polyethylene and maleic anhydride grafted polypropylene.

[0020] In the flame-retardant polyethylene cable material for ships of the present invention, maleic anhydride grafted polyethylene or maleic anhydride grafted polypropylene is used as a compatibilizer, and its molecular structure contains maleic anhydride groups. In the cable material system, the maleic anhydride groups can interact with the active sites in polymer molecules such as polyethylene and ethylene-vinyl acetate copolymer. At the same time, its polyethylene or polypropylene main chain has good compatibility with the matrix material. In this way, the compatibilizer reduces the interfacial tension between different polymers, promotes the mutual dispersion and fusion between the components, forms a stable blend system, and enhances the interfacial bonding force between the components.

[0021] As a further technical solution, the antioxidant includes one or more of antioxidant 1010, antioxidant 1076, and antioxidant 1098.

[0022] The present invention also provides a method for preparing a flame-retardant polyethylene cable material for ships, which comprises the following steps: The raw material components of the flame-retardant polyethylene cable material for ships are mixed, extruded into granules, sieved, air-cooled, and packaged to obtain the flame-retardant polyethylene cable material for ships.

[0023] The working principle and beneficial effects of the present invention are: In the present invention, composite zinc borate and metal hydroxide are used as flame retardants, wherein the composite zinc borate is obtained by compounding zinc borate with ferric tartrate and ferric citrate, thereby improving the flame retardancy of polyethylene cable materials for ships. Different from the prior art, the present invention directly uses untreated zinc borate to form a composite flame retardant. The present invention pays attention to the fact that zinc borate is prone to agglomeration and has poor flame retardant performance. Therefore, ferric tartrate and ferric citrate are used to compound zinc borate, which, on the one hand, improves the compatibility of zinc borate with the organic system and enables zinc borate to be evenly dispersed in the system. Secondly, ferric tartrate The iron ions in ferric citrate promote the formation of a char layer during combustion, isolating it from oxygen and heat. Furthermore, due to differences in their ligands, ferric tartaric acid and ferric citrate exhibit synergistic and complementary properties in promoting char layer formation. In the early stages of combustion, when temperatures are relatively low, the iron ions in ferric tartaric acid catalyze the carbonization of some polymer materials, building the initial framework of the char layer. As the fire spreads and the temperature rises, the iron ions in ferric citrate begin to play a role, further catalyzing the carbonization of more polymer materials, filling and reinforcing the char layer and making it denser and more complete. The two work together to improve the flame retardancy of polyethylene cable materials for ships. DETAILED DESCRIPTION

[0024] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0025] In the following comparative examples, the model of polyethylene is FB3003, the model of polyolefin elastomer (POE) is Engage 7457, the particle size of zinc borate is 800 mesh, the particle size of magnesium hydroxide is 800 mesh, the particle size of aluminum hydroxide is 800 mesh, the model of maleic anhydride grafted polyethylene is 41E755, the model of maleic anhydride grafted polypropylene is QB520E, the model of ethylene-vinyl acetate copolymer with a vinyl acetate mass fraction of 33% is Ateva 9030, the model of ethylene-vinyl acetate copolymer with a vinyl acetate mass fraction of 12% is Ateva 1241, the model of ethylene-vinyl acetate copolymer with a vinyl acetate mass fraction of 19% is Ateva 1941, and the model of ethylene-vinyl acetate copolymer with a vinyl acetate mass fraction of 9% is Ateva 1070.

[0026] Example 1 A flame-retardant polyethylene cable material for ships, comprising the following components in parts by weight: 75 parts of polyethylene, 20 parts of ethylene-vinyl acetate copolymer (33% by mass of vinyl acetate), 24 parts of polyolefin elastomer, 15 parts of a flame retardant, 5 parts of maleic anhydride-grafted polyethylene, 1 part of antioxidant 1010, and 2 parts of antioxidant 1076; The flame retardant is a composite of zinc borate, magnesium hydroxide and aluminum hydroxide in a mass ratio of 1:2:2; The preparation method of composite zinc borate comprises the following steps: Add ferric tartrate and ferric citrate to water, add zinc borate (the mass volume ratio of zinc borate to water is 1 g:30 mL, and the mass ratio of ferric tartrate, ferric citrate and zinc borate is 5:4:9), stir at 400 rpm at 70°C for 45 minutes, concentrate and dry to obtain composite zinc borate; The method for preparing a flame-retardant polyethylene cable material for ships comprises the following steps: The raw materials are mixed, extruded into granules, sieved, air-cooled, and packaged to obtain a flame-retardant polyethylene cable material for ships.

[0027] Example 2 A flame-retardant polyethylene cable material for ships, comprising the following components in parts by weight: 65 parts of polyethylene, 15 parts of ethylene-vinyl acetate copolymer (33% by mass of vinyl acetate), 20 parts of polyolefin elastomer, 10 parts of flame retardant, 5 parts of maleic anhydride grafted polypropylene, and 2 parts of antioxidant 1098; The flame retardant is a composite of zinc borate and aluminum hydroxide in a mass ratio of 1:3; The preparation method of composite zinc borate comprises the following steps: Add ferric tartrate and ferric citrate to water, add zinc borate (the mass volume ratio of zinc borate to water is 1 g:20 mL, and the mass ratio of ferric tartrate, ferric citrate and zinc borate is 1:4:9), stir at 300 rpm at 60°C for 60 min, concentrate and dry to obtain composite zinc borate; The method for preparing a flame-retardant polyethylene cable material for ships comprises the following steps: The raw materials are mixed, extruded into granules, sieved, air-cooled, and packaged to obtain a flame-retardant polyethylene cable material for ships.

[0028] Example 3 The only difference between this embodiment and embodiment 2 is that the mass ratio of ferric tartrate, ferric citrate and zinc borate in this embodiment is 4:4:9.

[0029] Example 4 The only difference between this embodiment and embodiment 2 is that the mass ratio of ferric tartrate, ferric citrate and zinc borate in this embodiment is 2:4:9.

[0030] Example 5 The only difference between this embodiment and embodiment 2 is that the mass ratio of ferric tartrate, ferric citrate and zinc borate in this embodiment is 3:4:9.

[0031] Example 6 The only difference between this embodiment and embodiment 5 is that the mass fraction of vinyl acetate in the ethylene-vinyl acetate copolymer in this embodiment is 12%.

[0032] Example 7 The only difference between this embodiment and Example 5 is that the ethylene-vinyl acetate copolymer in this embodiment is replaced by an equal mass of mixed ethylene-vinyl acetate copolymer, including an ethylene-vinyl acetate copolymer with a mass fraction of 33% of vinyl acetate and an ethylene-vinyl acetate copolymer with a mass fraction of 12% of vinyl acetate at a mass ratio of 3:1.

[0033] Example 8 The only difference between this embodiment and Example 5 is that the ethylene-vinyl acetate copolymer in this embodiment is replaced by an equal mass of mixed ethylene-vinyl acetate copolymer, including an ethylene-vinyl acetate copolymer with a mass fraction of 33% of vinyl acetate and an ethylene-vinyl acetate copolymer with a mass fraction of 12% of vinyl acetate at a mass ratio of 6:1.

[0034] Example 9 The only difference between this embodiment and Example 5 is that the ethylene-vinyl acetate copolymer in this embodiment is replaced by an equal mass of mixed ethylene-vinyl acetate copolymer, including an ethylene-vinyl acetate copolymer with a vinyl acetate mass fraction of 33% and an ethylene-vinyl acetate copolymer with a vinyl acetate mass fraction of 19% at a mass ratio of 6:1.

[0035] Example 10 The only difference between this embodiment and Example 5 is that the ethylene-vinyl acetate copolymer in this embodiment is replaced by an equal mass of mixed ethylene-vinyl acetate copolymers, including an ethylene-vinyl acetate copolymer with a mass fraction of 33% of vinyl acetate and an ethylene-vinyl acetate copolymer with a mass fraction of 9% of vinyl acetate at a mass ratio of 6:1.

[0036] Comparative Example 1 The only difference between this comparative example and Example 2 is that the preparation method of the composite zinc borate in this comparative example includes the following steps: Ferric citrate was added to water, and zinc borate was added (the mass volume ratio of zinc borate to water was 1 g:20 mL, and the mass ratio of ferric citrate to zinc borate was 5:9). The mixture was stirred at 300 rpm at 60° C. for 60 min, concentrated, and dried to obtain composite zinc borate.

[0037] Comparative Example 2 The only difference between this comparative example and Example 2 is that the preparation method of the composite zinc borate in this comparative example includes the following steps: Add ferric tartrate to water, add zinc borate (the mass volume ratio of zinc borate to water is 1 g:20 mL, and the mass ratio of ferric tartrate to zinc borate is 5:9), stir at 300 rpm at 60° C. for 60 min, concentrate, and dry to obtain composite zinc borate.

[0038] Comparative Example 3 The only difference between this comparative example and Example 2 is that the composite zinc borate in this comparative example is replaced with an equal mass of zinc borate.

[0039] Experimental Example 1 The flame-retardant polyethylene cable materials for ships prepared in Examples 1 to 5 and Comparative Examples 1 to 3 were made into Type IV specimens according to GB / T 2406.2-2009 "Determination of Combustion Behavior of Plastics by Oxygen Index Method Part 2: Room Temperature Test" and then tested for oxygen index according to Method A. The test results are shown in Table 1.

[0040] Table 1 Oxygen index test results

[0041] As can be seen from Table 1, the oxygen index of the flame-retardant polyethylene cable material for ships prepared in Examples 1 to 5 of the present invention reaches more than 31.7%. Therefore, the use of ferric tartrate and ferric citrate composite zinc borate in the present invention improves the flame retardancy of the flame-retardant polyethylene cable material for ships.

[0042] Experimental Example 2 The flame-retardant polyethylene cable materials for ships prepared in Examples 5-10 were prepared into Type 1A specimens according to GB / T 1040.2-2022, "Determination of Tensile Properties of Plastics - Part 2: Test Conditions for Molded and Extruded Plastics." The tensile strength was tested at a rate of 5 mm / min. The test results are shown in Table 2.

[0043] Table 2 Tensile strength test results

[0044] As can be seen from Table 2, the tensile strength of the flame-retardant polyethylene cable material for ships prepared in Examples 7 and 8 of the present invention reached more than 16.6 MPa. Therefore, the present invention uses an ethylene-vinyl acetate copolymer with a vinyl acetate mass fraction of 33% and an ethylene-vinyl acetate copolymer with a mass fraction of 12%, thereby improving the tensile strength of the flame-retardant polyethylene cable material for ships.

[0045] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A flame-retardant polyethylene cable material for ships, characterized in that: The raw materials include the following components in parts by weight: 65-75 parts of polyethylene, 15-20 parts of ethylene-vinyl acetate copolymer, 20-24 parts of polyolefin elastomer, 10-15 parts of flame retardant, 5-7 parts of compatibilizer, and 2-3 parts of antioxidant; The flame retardant is a composite of zinc borate and metal hydroxide; The preparation method of the composite zinc borate comprises the following steps: Ferric tartrate and ferric citrate are added into water, zinc borate is added, the mixture is stirred, concentrated and dried to obtain the composite zinc borate.

2. A flame-retardant polyethylene cable material for ships according to claim 1, characterized in that: The mass ratio of the ferric tartrate, ferric citrate and zinc borate is 2-3:4:

9.

3. A flame-retardant polyethylene cable material for ships according to claim 2, characterized in that: The mass ratio of the composite zinc borate to the metal hydroxide is 1:3-4; The metal hydroxide includes one or both of magnesium hydroxide and aluminum hydroxide.

4. The flame-retardant polyethylene cable material for ships according to claim 1, characterized in that: The stirring speed is 300-400 rpm, the temperature is 60-70° C., and the time is 45-60 min.

5. The flame-retardant polyethylene cable material for ships according to any one of claims 1 to 4, characterized in that: The ethylene-vinyl acetate copolymer includes a first ethylene-vinyl acetate copolymer and a second ethylene-vinyl acetate copolymer; The mass fraction of vinyl acetate in the first ethylene-vinyl acetate copolymer is 30% to 35%; The mass fraction of vinyl acetate in the second ethylene-vinyl acetate copolymer is 10% to 15%.

6. The flame-retardant polyethylene cable material for ships according to claim 5, characterized in that: The mass ratio of the first ethylene-vinyl acetate copolymer to the second ethylene-vinyl acetate copolymer is 3-6:

1.

7. The flame-retardant polyethylene cable material for ships according to claim 6, characterized in that: The mass ratio of the first ethylene-vinyl acetate copolymer to the second ethylene-vinyl acetate copolymer is 6:

1.

8. The flame-retardant polyethylene cable material for ships according to claim 1, characterized in that: The compatibilizer includes one of maleic anhydride grafted polyethylene and maleic anhydride grafted polypropylene.

9. The flame-retardant polyethylene cable material for ships according to claim 1, characterized in that: The antioxidant includes one or more of antioxidant 1010 , antioxidant 1076 , and antioxidant 1098 .

10. A method for preparing a flame-retardant polyethylene cable material for ships, for preparing the flame-retardant polyethylene cable material for ships according to any one of claims 1 to 9, characterized in that: The following steps are involved: The raw material components of the flame-retardant polyethylene cable material for ships are mixed, extruded into granules, sieved, air-cooled, and packaged to obtain the flame-retardant polyethylene cable material for ships.

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