Modified aluminum hydroxide, flame-retardant PE, preparation method and cable prepared from PE material

Abstract

The invention discloses modified aluminum hydroxide. The modified aluminum hydroxide is prepared from at least few of hexagonal boron nitride, isopropanol, aluminum chloride hydrate, a silane coupling agent n-butyl alcohol containing methacryloyloxy, ammonia water and aluminum hydroxide. The modified aluminum hydroxide provided by the invention has high flame retardant property and is suitable for the cable industry.

Description

Technical Field

[0001] The invention relates to the field of electric wires and cables, and in particular to modified aluminum hydroxide, flame-retardant PE, a preparation method and a cable made from the PE material. Background Art

[0002] In the cable industry, the selection of cable materials is crucial to the performance and service life of the cables. With the development of the materials industry, the flame retardant properties of cable materials are gradually improved while ensuring their mechanical properties. At present, the flame retardants used in the cable industry on the market are mainly phosphorus flame retardants, silicon flame retardants, inorganic metal flame retardants and bio-based flame retardants, etc. However, single-component halogen-free flame retardants face problems such as large addition amount and lower flame retardant effect than halogen-containing flame retardants. Therefore, it is very necessary to develop an efficient flame retardant. Summary of the invention

[0003] In view of the above-mentioned deficiencies in the prior art, the present invention proposes a modified aluminum hydroxide, a flame-retardant PE, a preparation method and a cable made from the PE material, aiming to solve the problem of insufficient low-smoke flame-retardant performance of current cable materials.

[0004] To achieve the above purpose, the present invention provides modified aluminum hydroxide, flame retardant PE, preparation method and cable made from the PE material. A modified aluminum hydroxide, the preparation material of the modified aluminum hydroxide at least includes a silane coupling agent containing a methacryloxy group and aluminum hydroxide.

[0005] Optionally, the preparation materials of the methacryloyloxy-containing silane coupling agent at least include terminal hydroxyl silicone oil, vinyl-containing alkoxysilane, methacryloyloxy-containing alkoxysilane and a basic catalyst.

[0006] Optionally, the terminal hydroxyl silicone oil is a silane with hydroxyl groups at both ends of the molecular chain, including one or more of methylphenyl terminal hydroxyl silicone oil, dimethyl terminal hydroxyl silicone oil and diphenyl terminal hydroxyl silicone oil.

[0007] Optionally, the vinyl-containing alkoxysilane is one or more of methylvinyldimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane and methylvinyldiethoxysilane.

[0008] Optionally, the alkoxysilane containing a methacryloxy group is one or two of γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane and methacryloxymethyltriethoxysilane.

[0009] Optionally, the alkaline catalyst is an alkaline anion exchange resin, including at least one of a strong base anion exchange resin, a weak base anion exchange resin and a strong and weak base mixed anion exchange resin.

[0010] A flame retardant PE, wherein the ingredients of the flame retardant PE are calculated by weight: 10-30 parts of PE resin; 5-20 parts of EVA resin; 30-60 parts of the above-mentioned modified aluminum hydroxide; 0-1 part of antioxidant; 0-2 parts of lubricant; and 0-1 part of flame retardant synergist.

[0011] Optionally, the PE resin is at least one of high-density polyethylene, low-density polyethylene and linear low-density polyethylene.

[0012] Optionally, the EVA resin includes an EVA resin having a VA content of 5%-33%.

[0013] Optionally, the modified aluminum hydroxide is 40-50 parts.

[0014] Optionally, the antioxidant is at least one of bis(octadecyl)hydroxylamine, tris[2,4-di-tert-butylphenyl]phosphite, pentaerythritol tetrakis(3-laurylthiopropionate), bis[3-[3-tert-butyl-4-hydroxy-5-methylphenyl]2,4,8,10-tetraoxaspiro[5,5]undecane-3,9-diylbis(2-methylpropane-2,1-diyl)ester), 1,5,8,12-tetrakis[4,6-bis(N-1,2,2,6,6-pentamethyl-4-piperidinylamino)-1,3,5-triazine-2-yl]-1,5,8,12-tetraazadodecane and N-salicylicylphthalimide.

[0015] Optionally, the flame retardant PE further includes a lubricant, and the lubricant is at least one of fatty acids, fatty amides, metal soaps and fatty alcohols.

[0016] Optionally, the flame retardant synergist is a silicon-based flame retardant.

[0017] In order to achieve the above object, the present invention also provides a method for preparing flame-retardant PE, comprising the following steps: preparing modified aluminum hydroxide: preparing modified aluminum hydroxide by surface adsorption method using the methacryloyloxy-containing silane coupling agent of claim 1 or 2 and aluminum hydroxide;

[0018] Preparation of flame-retardant PE: PE resin, EVA resin, modified aluminum hydroxide, antioxidant, lubricant and flame-retardant synergist are pre-mixed uniformly, and then kneaded in an internal mixer to prepare a molten blend; the molten blend is granulated in a twin-screw machine, followed by air cooling and vibration screening to finally obtain flame-retardant PE.

[0019] Optionally, the preparation method of the modified aluminum hydroxide comprises the following steps: mixing terminal hydroxyl silicone oil, vinyl alkoxysilane and methacryloxy alkoxysilane, heating and stirring, then adding an alkaline catalyst to synthesize a methacryloxy-containing silane coupling agent by a non-hydrolytic sol-gel method, adding the methacryloxy-containing silane coupling agent to aluminum hydroxide powder for dry modification, and fully crushing and mixing to obtain modified aluminum hydroxide.

[0020] In order to achieve the above object, the present invention further provides a PE cable, which is prepared by any one of the above-mentioned methods for preparing flame-retardant PE.

[0021] Beneficial effects of the present invention: In the present invention, aluminum hydroxide is modified by synthesis so that its surface contains a large number of silane coupling agent molecules, and its organic groups have good compatibility with the polymer matrix, serving as a bridge connecting the inorganic filler and the polymer, thereby improving the compatibility of the two. In addition, the surface activity of aluminum hydroxide is enhanced, and it is easier to disperse in the polymer matrix, thereby improving the stability and uniformity of the material, achieving the flame retardant effect of "small amount and high efficiency" of the flame retardant, and its compound use with a flame retardant synergist can reduce its dosage and achieve excellent flame retardant effect.

[0022] The present invention also uses the modified aluminum hydroxide to prepare flame-retardant PE, and the mixed components of PE resin, EVA resin, modified aluminum hydroxide, antioxidant, lubricant and flame retardant synergist are evenly mixed. By adding modified aluminum hydroxide, not only the compatibility of the matrix can be improved, but also the flame retardant ability of the PE material can be improved, and the flame retardant effect can be improved, thereby realizing the composite modification of the flame retardant PE and obtaining excellent flame retardant properties. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. It should be understood that the following embodiments are only used to explain the present invention and are not used to limit the present invention.

[0024] Unless defined otherwise, all technical and scientific terms used herein have the common meaning in the art to which the claimed subject matter belongs.

[0025] In order to facilitate the understanding of this embodiment, the symbols, instruments and terms are explained below:

[0026] PE: Polyethylene, polyethylene is a material made by the polymerization of ethylene monomers, which is odorless, non-toxic, and waxy. It has excellent low-temperature resistance, with a minimum operating temperature of -100 to -70°C, and good chemical stability, and can withstand the corrosion of most acids and alkalis. It is widely used in the manufacture of films, packaging materials, containers, pipes, monofilaments, wires and cables, daily necessities, etc., and can be used as high-frequency insulation materials for televisions, radars, etc.

[0027] EVA: Ethylene-Vinyl acetate copolymer, ethylene-vinyl acetate copolymer, is a general-purpose polymer. Due to the introduction of vinyl acetate monomer into the molecular chain, the crystallinity of EVA is improved, and the flexibility, impact resistance, filler solubility and heat sealing performance are improved. It is widely used in foam shoe materials, functional shed films, packaging films, hot melt adhesives, wires and cables, toys and other fields.

[0028] In the cable industry, the selection of cable materials is crucial to the performance and service life of the cables. With the development of the materials industry, the flame retardant properties of cable materials are gradually improved while ensuring their mechanical properties. At present, the flame retardants used in the cable industry on the market are mainly phosphorus flame retardants, silicon flame retardants, inorganic metal flame retardants and bio-based flame retardants, etc. However, single-component halogen-free flame retardants face problems such as large addition amount and lower flame retardant effect than halogen-containing flame retardants. Therefore, it is very necessary to develop an efficient flame retardant.

[0029] To solve the above problems, the present invention provides a modified aluminum hydroxide, a flame retardant PE, a preparation method and a cable made from the PE material. A modified aluminum hydroxide, characterized in that the preparation material of the modified aluminum hydroxide at least includes a silane coupling agent containing a methacryloxy group and aluminum hydroxide.

[0030] In the present invention, aluminum hydroxide is modified by synthesis so that its surface contains a large number of silane coupling agent molecules, and its organic groups have good compatibility with the polymer matrix, which serves as a bridge connecting the inorganic filler and the polymer, thereby improving the compatibility of the two. In addition, the surface activity of aluminum hydroxide is enhanced, and it is easier to disperse in the polymer matrix, thereby improving the stability and uniformity of the material, achieving the flame retardant effect of "small amount and high efficiency" of the flame retardant, and its compound use with the flame retardant synergist can reduce its dosage and achieve excellent flame retardant effect.

[0031] Furthermore, the preparation materials of the methacryloyloxy-containing silane coupling agent at least include terminal hydroxyl silicone oil, vinyl-containing alkoxysilane, methacryloyloxy-containing alkoxysilane and a basic catalyst.

[0032] In some embodiments, the preparation materials of the methacryloyloxy-containing silane coupling agent include hydroxyl-terminated silicone oil, vinyl-containing alkoxysilane, methacryloyloxy-containing alkoxysilane and a basic catalyst.

[0033] Furthermore, the terminal hydroxyl silicone oil is a silane with hydroxyl groups at both ends of the molecular chain, including one or more of methylphenyl terminal hydroxyl silicone oil, dimethyl terminal hydroxyl silicone oil and diphenyl terminal hydroxyl silicone oil.

[0034] In some embodiments, the hydroxy-terminated silicone oil includes methylphenyl hydroxy-terminated silicone oil.

[0035] Furthermore, the vinyl-containing alkoxysilane is one or more of methylvinyldimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane and methylvinyldiethoxysilane.

[0036] In some embodiments, the vinyl-containing alkoxysilane is methylvinyldimethoxysilane.

[0037] Further, the alkoxysilane containing a methacryloxy group is one or two of γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane and methacryloxymethyltriethoxysilane.

[0038] In some embodiments, the alkoxysilane containing a methacryloxy group is γ-methacryloxypropylmethyldimethoxysilane.

[0039] Furthermore, the alkaline catalyst is an alkaline anion exchange resin, including at least one of a strong alkaline anion exchange resin, a weak alkaline anion exchange resin and a strong and weak alkaline mixed anion exchange resin.

[0040] In some embodiments, the basic catalyst is a strong base anion exchange resin.

[0041] The present invention also proposes a flame retardant PE, characterized in that the ingredients of the flame retardant PE, measured in parts by weight, include: 10-30 parts of PE resin; 5-20 parts of EVA resin; 30-60 parts of the above-mentioned modified aluminum hydroxide; 0-1 part of antioxidant; 0-2 parts of lubricant; and 0-1 part of flame retardant synergist.

[0042] In some embodiments, the ingredients of the flame retardant PE, measured in parts by weight, preferably include: 10-30 parts of PE resin; 5-20 parts of EVA resin; 30-60 parts of the above-mentioned modified aluminum hydroxide; 0-1 part of antioxidant; 0-2 parts of lubricant; and 0-1 part of flame retardant synergist.

[0043] Furthermore, the PE resin is at least one of high-density polyethylene, low-density polyethylene and linear low-density polyethylene.

[0044] In some embodiments, the PE resin is preferably high density polyethylene.

[0045] Furthermore, the EVA resin includes an EVA resin having a VA content of 5%-33%.

[0046] In some embodiments, the EVA resin is an EVA resin having a VA content of 20%-33%.

[0047] Furthermore, the modified aluminum hydroxide is 40-50 parts.

[0048] In some embodiments, the modified aluminum hydroxide is preferably 50 parts.

[0049] Furthermore, the antioxidant is at least one of bis(octadecyl)hydroxylamine, tris[2,4-di-tert-butylphenyl]phosphite, pentaerythritol tetrakis(3-laurylthiopropionate), bis[3-[3-tert-butyl-4-hydroxy-5-methylphenyl]2,4,8,10-tetraoxaspiro[5,5]undecane-3,9-diylbis(2-methylpropane-2,1-diyl)ester), 1,5,8,12-tetrakis[4,6-bis(N-1,2,2,6,6-pentamethyl-4-piperidinylamino)-1,3,5-triazine-2-yl]-1,5,8,12-tetraazadodecane and N-salicylicylphthalimide.

[0050] In some embodiments, the antioxidant is preferably bis(octadecyl)hydroxylamine.

[0051] Adding antioxidants can prevent thermal oxidative degradation of elastomers and improve the heat resistance, aging resistance, electrical properties and mechanical properties of the materials.

[0052] Furthermore, the flame retardant PE also includes a lubricant, and the lubricant is at least one of fatty acids, aliphatic amides, metal soaps and fatty alcohols.

[0053] Lubricants can improve fluidity during processing, increase the impact strength of the material, reduce water absorption on the cable surface, improve cable scratches and surface defects, and reduce heat release rate and smoke generation, all of which help improve cable performance and safety.

[0054] In some embodiments, the lubricant is preferably a fatty acid-based lubricant.

[0055] Furthermore, the flame retardant synergist is a silicon-based flame retardant.

[0056] In some embodiments, the flame retardant synergist is at least one of an organic silicon flame retardant and / or an inorganic silicon flame retardant.

[0057] In order to solve the above problems, the present invention also provides a method for preparing flame-retardant PE, comprising the following steps:

[0058] S1: preparing modified aluminum hydroxide: preparing modified aluminum hydroxide by surface adsorption method using the above-mentioned silane coupling agent containing methacryloxy group and aluminum hydroxide;

[0059] In this scheme, the surface of the modified aluminum hydroxide contains a large number of silane coupling agent molecules, which have the characteristics of both inorganic flame retardant materials and silane coupling agents. Its organic group has good compatibility with the polymer matrix, and acts as a bridge connecting inorganic fillers and polymers, thereby improving the compatibility between the two. In addition, the surface activity of aluminum hydroxide is enhanced, and it is easier to disperse in the polymer matrix, thereby improving the stability and uniformity of the material, achieving the flame retardant effect of "small amount and high efficiency" of the flame retardant. The use of it in combination with a flame retardant synergist can reduce its dosage and achieve an excellent flame retardant effect.

[0060] S2: preparing flame-retardant PE: pre-mixing PE resin, EVA resin, modified aluminum hydroxide, antioxidant, lubricant and flame-retardant synergist, and then mixing them in an internal mixer to prepare a molten blend;

[0061] In some embodiments, internal mixing is performed in an internal mixer.

[0062] S3: The molten blend is pelletized in a twin-screw machine, followed by air cooling and vibration screening to finally obtain flame-retardant PE.

[0063] In some embodiments, extrusion granulation is achieved by a twin-screw extruder.

[0064] Furthermore, the preparation method of modified aluminum hydroxide comprises the following steps:

[0065] The terminal hydroxy silicone oil, the alkoxysilane containing vinyl and the alkoxysilane containing methacryloxy are mixed and heated and stirred, and then an alkaline catalyst is added to synthesize the methacryloyloxy-containing silane coupling agent by a non-hydrolytic sol-gel method, and the methacryloyloxy-containing silane coupling agent is added to aluminum hydroxide powder for dry modification, and the modified aluminum hydroxide is obtained after sufficient crushing and mixing.

[0066] In some embodiments, methylphenyl terminal hydroxyl silicone oil, methylvinyl dimethoxysilane and γ-methacryloxypropyl methyldimethoxysilane are added to a 100 mL three-necked flask equipped with a magnetic stirrer, a thermometer and a condensation reflux device, the system temperature is raised to 95°C, and then an alkaline anion exchange resin accounting for 1% of the total reactant mass fraction is added, and the reaction is kept at a constant temperature for 4 hours.

[0067] In some embodiments, after the reaction is completed, the product is filtered under reduced pressure to remove the anionic resin to obtain a filtrate. The filtrate is transferred to a round-bottom distillation flask and distilled under reduced pressure at 120°C / -0.096Mpa to obtain a final product as a light yellow transparent liquid.

[0068] In some embodiments, aluminum hydroxide powder dried at 120° C. is weighed, put into a universal grinder, 0.8% of a methacryloyloxy-containing silane coupling agent is dropped into the powder, and the powder is grinded in the universal grinder for 5 minutes to obtain modified aluminum hydroxide.

[0069] In order to solve the above problem, the present invention further provides a PE cable, which is prepared by the above method for preparing flame-retardant PE.

[0070] The content of the present invention is explained below through specific examples and data.

[0071] Embodiment 1:

[0072] Take methylphenyl terminal hydroxyl silicone oil, methylvinyl dimethoxysilane and γ-methacryloxypropyl methyl dimethoxysilane and add them to a 100mL three-necked flask with magnetic stirring, a thermometer and a condensation reflux device. The system temperature is raised to 95°C, and then a basic anion exchange resin accounting for 1% of the total reactant mass fraction is added, and the reaction is kept at a constant temperature for 4 hours. After the reaction is completed, the product is vacuum filtered to remove the anion resin to obtain a filtrate. The filtrate is transferred to a round-bottomed distillation flask and vacuum distilled at 120°C / -0.096Mpa to obtain a final product of a light yellow transparent liquid. Weigh the aluminum hydroxide powder dried at 120°C, put the aluminum hydroxide powder into a universal grinder, drop 0.8% of a silane coupling agent containing a methacryloxy group, and grind it in a universal grinder for 5 minutes to obtain a modified aluminum hydroxide.

[0073] 30 parts of PE resin, 10 parts of EVA resin, 50 parts of modified aluminum hydroxide, 0.5 parts of antioxidant, 1 part of lubricant and 0.5 parts of flame retardant synergist were put into an internal mixer for mixing, cutting into pieces, crushing and then granulating with a small twin-screw extruder to obtain flame retardant PE.

[0074] Embodiment 2:

[0075] The preparation method is the same as that of Example 1, except that:

[0076] Weigh the aluminum hydroxide powder dried at 120° C., put the aluminum hydroxide powder into a universal grinder, drop 1% of a silane coupling agent containing a methacryloyloxy group into the powder, grind the powder in the universal grinder for 5 minutes, and obtain modified aluminum hydroxide.

[0077] 30 parts of PE resin, 10 parts of EVA resin, 50 parts of modified aluminum hydroxide, 0.5 parts of antioxidant, 1 part of lubricant and 0.5 parts of flame retardant synergist were put into an internal mixer for mixing, cutting into pieces, crushing and then granulating with a small twin-screw extruder to obtain flame retardant PE.

[0078] Embodiment 3:

[0079] The preparation method is the same as that of Example 1, except that:

[0080] Weigh the aluminum hydroxide powder dried at 120° C., put the aluminum hydroxide powder into a universal grinder, drop 1.2% of a silane coupling agent containing a methacryloyloxy group into the powder, grind the powder in the universal grinder for 5 minutes, and obtain modified aluminum hydroxide.

[0081] 30 parts of PE resin, 10 parts of EVA resin, 50 parts of modified aluminum hydroxide, 0.5 parts of antioxidant, 1 part of lubricant and 0.5 parts of flame retardant synergist were put into an internal mixer for mixing, cutting into pieces, crushing and then granulating with a small twin-screw extruder to obtain flame retardant PE.

[0082] Embodiment 4:

[0083] The preparation method is the same as that of Example 1, except that:

[0084] Weigh the aluminum hydroxide powder dried at 120° C., put the aluminum hydroxide powder into a universal grinder, drop 1.4% of a methacryloyloxy-containing silane coupling agent, grind in the universal grinder for 5 minutes, and obtain modified aluminum hydroxide.

[0085] 30 parts of PE resin, 10 parts of EVA resin, 50 parts of modified aluminum hydroxide, 0.5 parts of antioxidant, 1 part of lubricant and 0.5 parts of flame retardant synergist were put into an internal mixer for mixing, cutting into pieces, crushing and then granulating with a small twin-screw extruder to obtain flame retardant PE.

[0086] Embodiment 5:

[0087] The preparation method is the same as that of Example 1, except that:

[0088] Weigh the aluminum hydroxide powder dried at 120° C., put the aluminum hydroxide powder into a universal grinder, drop 1.6% of a silane coupling agent containing a methacryloxy group into the powder, grind the powder in the universal grinder for 5 minutes, and obtain modified aluminum hydroxide.

[0089] 30 parts of PE resin, 10 parts of EVA resin, 50 parts of modified aluminum hydroxide, 0.5 parts of antioxidant, 1 part of lubricant and 0.5 parts of flame retardant synergist were put into an internal mixer for mixing, cutting into pieces, crushing and then granulating with a small twin-screw extruder to obtain flame retardant PE.

[0090] Embodiment 6:

[0091] The preparation method is the same as that of Example 1, except that:

[0092] Weigh the aluminum hydroxide powder dried at 120° C., put the aluminum hydroxide powder into a universal grinder, drop 1% of a silane coupling agent containing a methacryloyloxy group into the powder, grind the powder in the universal grinder for 5 minutes, and obtain modified aluminum hydroxide.

[0093] 30 parts of PE resin, 10 parts of EVA resin, 45 parts of modified aluminum hydroxide, 0.5 parts of antioxidant, 1 part of lubricant and 0.5 parts of flame retardant synergist were put into an internal mixer for mixing, cutting into pieces, crushing and then granulating with a small twin-screw extruder to obtain flame retardant PE.

[0094] Embodiment 7:

[0095] The preparation method is the same as that of Example 1, except that:

[0096] Weigh the aluminum hydroxide powder dried at 120° C., put the aluminum hydroxide powder into a universal grinder, drop 1.2% of a silane coupling agent containing a methacryloyloxy group into the powder, grind the powder in the universal grinder for 5 minutes, and obtain modified aluminum hydroxide.

[0097] 30 parts of PE resin, 10 parts of EVA resin, 45 parts of modified aluminum hydroxide, 0.5 parts of antioxidant, 1 part of lubricant and 0.5 parts of flame retardant synergist were put into an internal mixer for mixing, cutting into pieces, crushing and then granulating with a small twin-screw extruder to obtain flame retardant PE.

[0098] Comparative Example 1:

[0099] 30 parts of PE resin, 10 parts of EVA resin, 50 parts of aluminum hydroxide, 0.5 parts of antioxidant, 1 part of lubricant and 0.5 parts of flame retardant synergist were put into an internal mixer for mixing, cutting into pieces, crushing and then granulating with a small twin-screw extruder to obtain flame retardant PE.

[0100] Comparative Example 2:

[0101] The preparation method is the same as that of Example 2, except that:

[0102] 30 parts of PE resin, 10 parts of EVA resin, 60 parts of modified aluminum hydroxide, 0.5 parts of antioxidant, 1 part of lubricant and 0.5 parts of flame retardant synergist were put into an internal mixer for mixing, cutting into pieces, crushing and then granulating with a small twin-screw extruder to obtain flame retardant PE.

[0103] Comparative Example 3:

[0104] The preparation method is the same as that of Example 3, except that:

[0105] 30 parts of PE resin, 10 parts of EVA resin, 40 parts of modified aluminum hydroxide, 10 parts of aluminum hydroxide, 0.5 parts of antioxidant, 1 part of lubricant and 0.5 parts of flame retardant synergist were put into an internal mixer for mixing, cutting into pieces, crushing and then granulating with a small twin-screw extruder to obtain flame retardant PE.

[0106] Comparative Example 4:

[0107] The preparation method is the same as that of Example 3, except that:

[0108] 30 parts of PE resin, 10 parts of EVA resin, 55 parts of modified aluminum hydroxide, 0.5 parts of antioxidant, 1 part of lubricant and 0.5 parts of flame retardant synergist were put into an internal mixer for mixing, cutting into pieces, crushing and then granulating with a small twin-screw extruder to obtain flame retardant PE.

[0109] The components and important preparation variables of Examples 1-7 and Comparative Examples 1-4 are summarized in Table 1.

[0110] Table 1. Components of Examples 1-7 and Comparative Examples 1-4 of the present invention

[0111]

[0112] According to relevant test standards, the flame retardant performance test of oxygen index data was performed on the flame retardant PE in the above Examples 1-7 and Comparative Examples 1-4, and the test results were recorded in the following Table 2:

[0113] Table 2. Flame retardant properties of Examples 1-7 of the present invention and Comparative Examples 1-4

[0114] Oxygen index / % Example 1 30 Example 2 32 Example 3 33 Example 4 31.5 Example 5 32.5 Example 6 32 Example 7 32.5 Comparative Example 1 28 Comparative Example 2 34 Comparative Example 3 32 Comparative Example 4 33.5

[0115] The oxygen index refers to the minimum oxygen concentration required to maintain combustion under specified test conditions. The larger the oxygen index, the better the flame retardant properties of the material and the more difficult it is to burn. According to the above test results, it can be seen that 50 parts of modified aluminum hydroxide are added in Examples 1-5. The difference is that in the modified aluminum hydroxide added in Example 1, the concentration of methacryloxy in the silane coupling agent is different. In Examples 1 to 5, the concentration of methacryloxy in the added silane coupling agent is 0.5%, 1%, 1.2%, 1.4% and 1.6%, respectively. The test results show that the oxygen index of Examples 1 to 5 is 30%, 32%, 33%, 31.5% and 32.5%, respectively. By comparing Examples 1 to 5, it can be concluded that in the preparation process of modified aluminum hydroxide, the concentration of methacryloxy in the silane coupling agent plays an important role in the flame retardancy of the modified aluminum hydroxide, but the higher the concentration of methacryloxy is, the better. Too high or too low a concentration of methacryloxy cannot achieve an ideal flame retardant effect. It can be concluded from the data of Examples 1 to 5 that when the concentration of methacryloxy is 1.2%, the flame retardant effect of the prepared flame retardant PE is optimal. By comparing the data of Example 6 with that of Example 2, and by comparing the data of Example 7 with that of Example 3, it can be concluded that when the amount of modified aluminum hydroxide added is reduced, the flame retardant properties of the prepared flame retardant PE will also decrease. 50 parts of modified aluminum hydroxide were added in Example 3, and 50 parts of aluminum hydroxide were added in Comparative Example 1. By comparing Example 3 with Comparative Example 1, it can be concluded that modified aluminum hydroxide can achieve more effective flame retardancy, and the use of modified aluminum hydroxide can prepare cable materials with better flame retardant properties; 60 parts of modified aluminum hydroxide with a methacryloxy concentration of 1% were added in Comparative Example 2, 50 parts of modified aluminum hydroxide with a methacryloxy concentration of 1% were added in Example 2, and 50 parts of modified aluminum hydroxide with a methacryloxy concentration of 1.2% were added in Example 3. By comparing Example 2, Comparative Example 2 and Example 3, , it can be concluded that when the amount of modified aluminum hydroxide added is 60 parts, its flame retardant effect is better than that of Example 2 and Example 3, and the improvement of flame retardant performance by increasing modified aluminum hydroxide is more intuitive and effective than increasing the concentration of methacryloxy in the silane coupling agent; 50 parts of modified aluminum hydroxide are added in Example 3, 40 parts of modified aluminum hydroxide and 10 parts of aluminum hydroxide are added in Comparative Example 3, and 55 parts of modified aluminum hydroxide are added in Comparative Example 4, and the concentration of methacryloxy in the silane coupling agent is the same, which is 1.2%. It can be concluded that the flame retardant performance of the prepared flame retardant PE increases with the increase of the number of modified aluminum hydroxide. Therefore, the modified aluminum hydroxide and flame retardant PE proposed by the present invention have the characteristics of high efficiency flame retardancy and have broad application prospects in the industrial cable and new energy cable industries.

[0116] The above are only preferred embodiments of the present invention, and do not limit the patent scope of the present invention. For those skilled in the art, the present invention may have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the patent protection scope of the present invention.

Claims

1. A modified aluminum hydroxide, characterized in that: The preparation materials of the modified aluminum hydroxide at least include a silane coupling agent containing a methacryloxy group and aluminum hydroxide.

2. The modified aluminum hydroxide according to claim 1, characterized in that The preparation materials of the methacryloyloxy-containing silane coupling agent at least include terminal hydroxyl silicone oil, vinyl-containing alkoxysilane, methacryloyloxy-containing alkoxysilane and a basic catalyst.

3. The modified aluminum hydroxide according to claim 2, characterized in that The terminal hydroxyl silicone oil is a silane with hydroxyl groups at both ends of the molecular chain, including one or more of methylphenyl terminal hydroxyl silicone oil, dimethyl terminal hydroxyl silicone oil and diphenyl terminal hydroxyl silicone oil.

4. The modified aluminum hydroxide according to claim 2, characterized in that The vinyl-containing alkoxysilane is one or more of methylvinyldimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane and methylvinyldiethoxysilane.

5. The modified aluminum hydroxide according to claim 2, characterized in that The alkoxysilane containing a methacryloxy group is one or both of γ-methacryloxypropylmethyldimethoxysilane and γ-methacryloxypropyltrimethoxysilane.

6. The modified aluminum hydroxide according to claim 2, characterized in that The alkaline catalyst is an alkaline anion exchange resin, including at least one of a strong alkaline anion exchange resin, a weak alkaline anion exchange resin and a strong and weak alkaline mixed anion exchange resin.

7. A flame retardant PE, characterized in that: The ingredients of the flame retardant PE are calculated by weight and include: PE resin 10-30 parts; 5-20 parts of EVA resin; 30-60 parts of the modified aluminum hydroxide according to claim 1 or 2; Antioxidant 0-1 part; Lubricant 0-2 parts; Flame retardant synergist 0-1 part.

8. The flame-retardant PE according to claim 7, characterized in that: The PE resin is at least one of high-density polyethylene, low-density polyethylene and linear low-density polyethylene.

9. The flame-retardant PE according to claim 7, characterized in that: The EVA resin includes an EVA resin with a vinyl acetate (VA) content of 5% to 33%.

10. The flame-retardant PE according to claim 7, characterized in that: The modified aluminum hydroxide is 40-50 parts.

11. The flame-retardant PE according to claim 7, characterized in that: The antioxidant is at least one of bis(octadecyl)hydroxylamine, tris[2,4-di-tert-butylphenyl]phosphite, pentaerythritol tetrakis(3-laurylthiopropionate), bis[3-[3-tert-butyl-4-hydroxy-5-methylphenyl]2,4,8,10-tetraoxaspiro[5,5]undecane-3,9-diylbis(2-methylpropane-2,1-diyl)ester), 1,5,8,12-tetrakis[4,6-bis(N-1,2,2,6,6-pentamethyl-4-piperidinylamino)-1,3,5-triazine-2-yl]-1,5,8,12-tetraazadodecane and N-salicylicylphthalimide.

12. The flame-retardant PE according to claim 7, characterized in that: The flame retardant PE further comprises a lubricant, and the lubricant is at least one of fatty acids, fatty amides, metal soaps and fatty alcohols.

13. The flame-retardant PE according to claim 7, characterized in that: The flame retardant synergist is a silicon-based flame retardant.

14. A method for preparing flame-retardant PE, characterized in that: The following steps are involved: Preparation of modified aluminum hydroxide: preparing modified aluminum hydroxide by surface adsorption method using the methacryloyloxy-containing silane coupling agent of claim 1 or 2 and aluminum hydroxide; Preparation of flame-retardant PE: PE resin, EVA resin, modified aluminum hydroxide, antioxidant, lubricant and flame retardant synergist are pre-mixed uniformly, and then kneaded in an internal mixer to prepare a molten blend; The molten blend is granulated in a twin-screw machine, followed by air cooling and vibration screening to finally obtain flame-retardant PE.

15. The method for preparing flame-retardant PE according to claim 14, characterized in that: The preparation method of the modified aluminum hydroxide comprises the following steps: The terminal hydroxy silicone oil, the alkoxysilane containing vinyl and the alkoxysilane containing methacryloxy are mixed and heated and stirred, and then an alkaline catalyst is added to synthesize the methacryloyloxy-containing silane coupling agent by a non-hydrolytic sol-gel method, and the methacryloyloxy-containing silane coupling agent is added to aluminum hydroxide powder for dry modification, and the modified aluminum hydroxide is obtained after sufficient crushing and mixing.

16. A PE cable, characterized in that: The cable is prepared by the preparation method according to claim 10.

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