Flame-retardant high-temperature-resistant modified plastic and processing method thereof

Abstract

The invention relates to the technical field of polyethylene plastics, and discloses a flame-retardant high-temperature-resistant modified plastic and a processing method thereof. The flame-retardant high-temperature-resistant modified plastic is prepared from the following raw materials in parts by weight: 50 to 70 parts of polyethylene resin, 30 to 50 parts of ethylene-vinyl acetate copolymer, 0.6 to 1.5 parts of acrylate malic acid grafted polyethylene, 40 to 70 parts of aluminum hydroxide, 15 to 30 parts of melamine phosphate flame retardant and the like. The side chain of the acrylate malic acid grafted polyethylene contains ester groups and a large amount of carboxyl groups, so that the compatibility between aluminum hydroxide and polyethylene and EVA components in the plastic is improved, the plastic keeps good tensile strength, elongation at break and high temperature resistance, and the plastic has higher thermal decomposition temperature.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of polyethylene plastic, in particular to a kind of flame-retardant high-temperature-resistant modified plastic and its processing method. BACKGROUND

[0002] Polyethylene plastic is light, transparent, high toughness, excellent corrosion resistance, and is widely used.Ethylene-vinyl acetate copolymer is a kind of excellent elastomer material, good high-temperature resistance, adding to polyethylene, polyvinyl chloride and other plastics, can improve the mechanical strength, heat resistance and other properties of plastics.However, polyethylene, ethylene-vinyl acetate copolymer are flammable materials, there is a big security risk, the practical application in the field of fire-retardant is also limited.

[0003] Aluminum hydroxide is a common flame retardant, cheap and easy to get, good flame retardant performance, but when aluminum hydroxide is applied to flame-retardant polyethylene, EVA and other materials, there is a large amount of use, and the compatibility of polyethylene, EVA is poor, which seriously affects the mechanical properties, high-temperature resistance and other problems of the material.Usually need to add compatibilizer, such as maleic anhydride grafted polyethylene, maleic anhydride grafted EVA, etc.The compounding of aluminum hydroxide and nitrogen-phosphorus flame retardant can reduce the use amount of aluminum hydroxide and have a synergistic flame-retardant effect.The present application aims to improve the poor compatibility of aluminum hydroxide with polyethylene and EVA, improve the flame retardance, high-temperature resistance and mechanical properties of polyethylene material. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application solves the problem of poor compatibility of aluminum hydroxide with polyethylene and EVA, so that polyethylene has good flame retardance, high-temperature resistance and mechanical properties.

[0005] Technical scheme: a kind of flame-retardant high-temperature-resistant modified plastic and its processing method, by weight fraction, raw materials include 50-70 parts of polyethylene resin, 30-50 parts of ethylene-vinyl acetate copolymer, 0.6-1.5 parts of acrylic acid ester malic acid grafted polyethylene, 40-70 parts of aluminum hydroxide, 15-30 parts of melamine phosphoric acid flame retardant, 0.15-0.25 parts of antioxidant.

[0006] The processing method of flame-retardant high-temperature-resistant modified plastic is: acrylic acid ester malic acid grafted polyethylene, aluminum hydroxide are added to the mixing machine for primary mixing, then polyethylene resin, ethylene-vinyl acetate copolymer, melamine phosphoric acid flame retardant and antioxidant are added for secondary mixing, then the material is extruded in a screw extruder, granulated, and then injected in an injection molding machine to obtain the flame-retardant high-temperature-resistant modified plastic.

[0007] Preferably, the temperature during primary mixing is 60-75℃, and the time is 20-30min;the time for secondary mixing is 20-40min.

[0008] Preferably, the temperature of the 1-5 stages of the screw extruder is 140-190 DEG C, and the screw rotation speed is 100-150 r / min.

[0009] Preferably, the temperature of the injection molding machine is 180-190 DEG C, and the pressure is 30-40 MPa.

[0010] Preferably, the melamine phosphate flame retardant comprises melamine phosphate and melamine polyphosphate.

[0011] Preferably, the antioxidant comprises antioxidant 1010 and antioxidant 168.

[0012] Preferably, the preparation method of the acrylate malic acid grafted polyethylene comprises the following steps: mixing polyethylene resin, acrylate malic acid and dicumyl peroxide, adding them into a screw extruder, extruding, adding the product into xylene, heating and refluxing, pouring the solution into acetone, washing the precipitate with acetone after filtration, and drying to obtain acrylate malic acid grafted polyethylene.

[0013] Preferably, the polyethylene resin is used in an amount of 100 parts, the acrylate malic acid is used in an amount of 6-15 parts, and the dicumyl peroxide is used in an amount of 0.12-0.3 parts by weight.

[0014] Preferably, the temperature of the 1-5 stages of the screw extruder is 140-185 DEG C, and the screw rotation speed is 40-60 r / min.

[0015] The application has the beneficial technical effects that the acrylate malic acid is used to melt graft polyethylene to obtain acrylate malic acid grafted polyethylene, which is used as a compatibilizer of an aluminum hydroxide flame retardant, and is blended with a melamine phosphate flame retardant, polyethylene resin, ethylene-vinyl acetate copolymer and the like to obtain a flame-retardant high-temperature-resistant modified plastic.

[0016] The side chain of the acrylate malic acid grafted polyethylene of the application contains ester groups and a large number of carboxyl groups, which can interact with the surface of aluminum hydroxide, so that the acrylate malic acid grafted polyethylene is used as a compatibilizer to improve the compatibility between aluminum hydroxide and the polyethylene component in the plastic. Furthermore, the acrylate malic acid grafted polyethylene contains polyethylene molecular chains and ester groups, and has better structural similarity with EVA, which further improves the compatibility between aluminum hydroxide and the EVA component in the plastic, so that the aluminum hydroxide can be uniformly dispersed in the EVA-polyethylene modified plastic matrix, the aluminum hydroxide can play a better flame-retardant role, and the influence of the aluminum hydroxide on the mechanical properties of the plastic can be reduced, so that good tensile strength and elongation at break can be maintained.

[0017] The acrylate malic acid grafted polyethylene of the present application contains a large amount of carboxyl groups, which form hydrogen bond interaction force with the amino groups of melamine phosphate, etc., which is beneficial to improve the interfacial properties between melamine phosphate and polyethylene and EVA, reduce the influence of melamine phosphate on the mechanical properties of plastics, and make the modified polyethylene plastics maintain good tensile properties.

[0018] The aluminum hydroxide and melamine phosphate flame retardant of the present application are uniformly dispersed in the EVA-polyethylene matrix, and are not easy to form phase separation to produce defects, so that the plastic maintains good high temperature resistance and has a higher thermal decomposition temperature. DETAILED DESCRIPTION

[0019] In order to make the content of the present application more convenient to understand, the technical solutions of the present application will be further described below in combination with specific embodiments, but the present application is not limited thereto.

[0020] Polyethylene resin brand LL0220KJ, Dongguan Hengxin Plastic Raw Material Co., Ltd. Ethylene-vinyl acetate copolymer EVA brand 7470m, Dongguan Hengxin Plastic Raw Material Co., Ltd.

[0021] According to the method of the journal Carbohydrate Polymers, Volume 135, 1, January 2016, Pages 86-93, document "Anti-crease finishing of cotton fabrics based on crosslinking of cellulose with acryloyl malic acid" (DOI number 10.1016 / j.carbpol.2015.08.014), acryloyl chloride and malic acid are reacted to obtain acrylate malic acid, the structural formula of which is .

[0022] Example 1

[0023] (1) 200g of polyethylene resin, 12g of acrylate malic acid, and 0.24g of dicumyl peroxide were mixed and added to a screw extruder, the temperature of 1-5 segments was 140℃, 160℃, 175℃, 185℃, and 180℃, the screw rotation speed was 60r / min, and the product was extruded, then added to dimethylbenzene and heated to 140℃, stirred and refluxed for 2h, then the solution was poured into acetone, the precipitate was washed with acetone after filtration, and dried to obtain acrylate malic acid grafted polyethylene.

[0024] (2) 150 g of the acrylate-malic acid grafted polyethylene, 7 kg of aluminum hydroxide were added into a mixer, mixed at 70 °C for 20 min, then 7 kg of polyethylene resin, 3 kg of ethylene-vinyl acetate copolymer, 1.5 kg of melamine phosphate MP, 25 g of antioxidant 1010 were added, mixed for 40 min; the material was extruded in a screw extruder, the temperature of 1-5 segments was 140 °C, 160 °C, 175 °C, 190 °C, 190 °C, the screw rotation speed was 100 r / min, granulation was then performed, and injection molding was performed in an injection molding machine at a temperature of 190 °C and a pressure of 40 MPa to obtain the flame-retardant high-temperature-resistant modified plastic.

[0025] Example 2

[0026] (1) 200 g of polyethylene resin, 30 g of acrylate-malic acid, 0.6 g of dicumyl peroxide were mixed and added into a screw extruder, the temperature of 1-5 segments was 140 °C, 160 °C, 175 °C, 185 °C, 180 °C, the screw rotation speed was 60 r / min, and extrusion was performed; the product was added into dimethylbenzene, heated to 140 °C, stirred and refluxed for 2 h, the solution was poured into acetone, the precipitate was washed with acetone after filtration, and dried to obtain acrylate-malic acid grafted polyethylene.

[0027] (2) 100 g of the acrylate-malic acid grafted polyethylene, 5.5 kg of aluminum hydroxide were added into a mixer, mixed at 60 °C for 30 min, then 6 kg of polyethylene resin, 4 kg of ethylene-vinyl acetate copolymer, 2.2 kg of melamine phosphate MP, 15 g of antioxidant 168 were added, mixed for 40 min; the material was extruded in a screw extruder, the temperature of 1-5 segments was 140 °C, 160 °C, 175 °C, 190 °C, 190 °C, the screw rotation speed was 150 r / min, granulation was then performed, and injection molding was performed in an injection molding machine at a temperature of 180 °C and a pressure of 40 MPa to obtain the flame-retardant high-temperature-resistant modified plastic.

[0028] Example 3

[0029] (1) 200 g of polyethylene resin, 30 g of acrylate-malic acid, 0.6 g of dicumyl peroxide were mixed and added into a screw extruder, the temperature of 1-5 segments was 140 °C, 160 °C, 175 °C, 185 °C, 180 °C, the screw rotation speed was 60 r / min, and extrusion was performed; the product was added into dimethylbenzene, heated to 140 °C, stirred and refluxed for 2 h, the solution was poured into acetone, the precipitate was washed with acetone after filtration, and dried to obtain acrylate-malic acid grafted polyethylene.

[0030] (2) 60 g of acrylic acid grafted polyethylene, 4 kg of aluminum hydroxide were added into a mixer, mixed at 75 °C for 20 min, then 5 kg of polyethylene resin, 5 kg of ethylene-vinyl acetate copolymer, 3 kg of melamine polyphosphate MPP, 23 g of antioxidant 1010 were added and mixed for 20 min; the material was extruded in a screw extruder, the temperature of 1-5 segments was 140 °C, 160 °C, 175 °C, 190 °C, 190 °C, the screw rotation speed was 150 r / min, granulation was then performed, and then injection molding was performed in an injection molding machine, the temperature was 190 °C, and the pressure was 30 MPa, to obtain a flame-retardant high-temperature-resistant modified plastic.

[0031] Comparative Example 1

[0032] (1) 7 kg of aluminum hydroxide, 7 kg of polyethylene resin, 3 kg of ethylene-vinyl acetate copolymer, 1.5 kg of melamine phosphate MP, 25 g of antioxidant 1010 were mixed for 40 min; the material was extruded in a screw extruder, the temperature of 1-5 segments was 140 °C, 160 °C, 175 °C, 190 °C, 190 °C, the screw rotation speed was 100 r / min, granulation was then performed, and then injection molding was performed in an injection molding machine, the temperature was 190 °C, and the pressure was 40 MPa, to obtain a modified plastic.

[0033] Comparative Example 2

[0034] (1) 200 g of polyethylene resin, 12 g of acrylic acid, and 0.24 g of dicumyl peroxide were mixed and added into a screw extruder, the temperature of 1-5 segments was 140 °C, 160 °C, 175 °C, 185 °C, 180 °C, and the screw rotation speed was 60 r / min, to extrude the product; the product was added into dimethylbenzene, heated to 140 °C, and stirred to reflux for 2 h; the solution was poured into acetone, the precipitate was washed with acetone after filtration, and dried, to obtain acrylic acid grafted polyethylene.

[0035] (2) 150 g of acrylic acid grafted polyethylene, 7 kg of aluminum hydroxide were added into a mixer, mixed at 70 °C for 20 min, then 7 kg of polyethylene resin, 3 kg of ethylene-vinyl acetate copolymer, 1.5 kg of melamine phosphate MP, 25 g of antioxidant 1010 were added and mixed for 40 min; the material was extruded in a screw extruder, the temperature of 1-5 segments was 140 °C, 160 °C, 175 °C, 190 °C, 190 °C, the screw rotation speed was 100 r / min, granulation was then performed, and then injection molding was performed in an injection molding machine, the temperature was 190 °C, and the pressure was 40 MPa, to obtain a modified plastic.

[0036] Comparative Example 3

[0037] (1) 200 g of polyethylene resin, 12 g of maleic anhydride, and 0.24 g of dicumyl peroxide are mixed and added to a screw extruder, the temperature of 1-5 sections is 140°C, 160°C, 175°C, 185°C, and 180°C, the screw rotation speed is 60 r / min, extrusion is performed, the product is added to dimethylbenzene, heated to 140°C, stirred and refluxed for 2 h, the solution is poured into acetone, the precipitate is washed with acetone after filtration, and dried to obtain maleic anhydride grafted polyethylene.

[0038] (2) 150 g of maleic anhydride grafted polyethylene, 7 kg of aluminum hydroxide, 7 kg of polyethylene resin, 3 kg of ethylene-vinyl acetate copolymer, 1.5 kg of melamine phosphate MP, and 25 g of antioxidant 1010 are added to a mixer, mixed at 70°C for 20 min, and then extruded in a screw extruder, the temperature of 1-5 sections is 140°C, 160°C, 175°C, 190°C, and 190°C, the screw rotation speed is 100 r / min, granulation is performed, and then injection molding is performed in an injection molding machine at a temperature of 190°C and a pressure of 40 MPa to obtain modified plastic.

[0039] Comparative Example 4

[0040] (1) 2-(methacryloyloxy)acetic acid is prepared according to the method of the journal J. Am. Chem. Soc. 2024, 146, 23, 16257-16267, document “β-Triketones as Reactive Handles for Polymer Diversification via Dynamic Catalyst-Free Diketoenamine Click Chemistry” (DOI number 10.1021 / jacs.4c04664), and the structural formula is .

[0041] (2) 200 g of polyethylene resin, 12 g of 2-(methacryloyloxy)acetic acid, and 0.24 g of dicumyl peroxide are mixed and added to a screw extruder, the temperature of 1-5 sections is 140°C, 160°C, 175°C, 185°C, and 180°C, the screw rotation speed is 60 r / min, extrusion is performed, the product is added to dimethylbenzene, heated to 140°C, stirred and refluxed for 2 h, the solution is poured into acetone, the precipitate is washed with acetone after filtration, and dried to obtain 2-(methacryloyloxy)acetic acid grafted polyethylene.

[0042] (3) 150 g of 2-(methacryloyloxy)acetic acid grafted polyethylene, 7 kg of aluminum hydroxide were added into a mixer, mixed at 70 °C for 20 min, then 7 kg of polyethylene resin, 3 kg of ethylene-vinyl acetate copolymer, 1.5 kg of melamine phosphate MP, 25 g of antioxidant 1010 were added, mixed for 40 min; the material was extruded in a screw extruder, the temperature of 1-5 segments was 140 °C, 160 °C, 175 °C, 190 °C, 190 °C, the screw rotation speed was 100 r / min, granulation was then carried out in an injection molding machine, the temperature was 190 °C, the pressure was 40 MPa, to obtain the modified plastic.

[0043] The combustion performance was tested according to standard GB / T 2406.1-2008.

[0044] The tensile properties were tested according to standard GB / T 1040.1-2018.

[0045] The modified plastic was placed in a thermal gravimetric analyzer and tested in a nitrogen atmosphere, with a temperature rise rate of 5 °C / min from 25 °C to 700 °C.

[0046] Table 1 Properties of modified plastic

[0047]

[0048] According to the results of Table 1 obtained by testing, the EVA ethylene-vinyl acetate copolymer-polyethylene modified plastic of Comparative Example 1, Examples 1-3 added with acrylate malic acid grafted polyethylene contains polyethylene molecular chains, and the side chains introduce acrylate malic acid polymers containing ester groups and a large number of carboxyl groups, which can interact with the surface of aluminum hydroxide, thereby making the acrylate malic acid grafted polyethylene act as a compatibilizer to improve the compatibility between aluminum hydroxide and the polyethylene component in the plastic, and the acrylate malic acid grafted polyethylene contains polyethylene molecular chains and ester groups, which have better structural similarity with EVA, further improving the compatibility between aluminum hydroxide and the EVA component in the plastic, making aluminum hydroxide uniformly dispersed in the EVA-polyethylene modified plastic matrix, making aluminum hydroxide play a better flame-retardant role, and reducing the influence of aluminum hydroxide on the mechanical properties of the plastic, and the acrylate malic acid grafted polyethylene contains a large number of carboxyl groups, which form hydrogen bond interaction with the amino groups of melamine phosphate, etc., which is beneficial to improve the interfacial properties between melamine phosphate and polyethylene and EVA, reduce the influence of melamine phosphate on the mechanical properties of the plastic, and make the modified polyethylene plastic maintain good tensile properties, while the modified plastic has a higher initial thermal decomposition temperature (T 5% ) and excellent high temperature resistance.

[0049] Comparative Example 2 uses a conventional acrylic acid grafted polyethylene as the compatibilizer, which does not contain ester groups and has a low carboxyl content; Comparative Example 3 uses a conventional maleic anhydride grafted polyethylene as the compatibilizer, which does not contain ester groups; Comparative Example 4 uses a 2-(methacryloyloxy) acetic acid grafted polyethylene, which has a low carboxyl content, all of which have a lower compatibilization effect on aluminum hydroxide than the acrylic acid ester malic acid grafted polyethylene of Example 1, and do not have a good effect on improving the interfacial properties between melamine phosphate and polyethylene and EVA, which affects the flame retardant properties and mechanical properties of the modified polyethylene plastic, and the limiting oxygen index and tensile properties are low.

[0050] The above description is only the preferred embodiment of the present application, and any equivalent changes and modifications made within the scope of the patent application of the present application shall be included in the scope of the present application.

Claims

1. A flame-retardant and high-temperature resistant modified plastic, characterized in that, By weight, the raw materials of the flame-retardant and high-temperature resistant modified plastic include 50-70 parts polyethylene resin, 30-50 parts ethylene-vinyl acetate copolymer, 0.6-1.5 parts acrylate-malic acid grafted polyethylene, 40-70 parts aluminum hydroxide, 15-30 parts melamine phosphate flame retardant, and 0.15-0.25 parts antioxidant.

2. The flame-retardant and high-temperature resistant modified plastic according to claim 1, characterized in that, The melamine phosphate flame retardant includes melamine phosphate and melamine polyphosphate.

3. The flame-retardant and high-temperature resistant modified plastic according to claim 1, characterized in that, The antioxidants include antioxidant 1010 and antioxidant 168.

4. The flame-retardant and high-temperature resistant modified plastic according to claim 1, characterized in that, The preparation method of the acrylate-malic acid grafted polyethylene is as follows: polyethylene resin, acrylate-malic acid, and dicumyl peroxide are mixed, added to a screw extruder, extruded, the product is added to xylene, heated and refluxed, the solution is poured into acetone, filtered, the precipitate is washed, and dried to obtain acrylate-malic acid grafted polyethylene.

5. The flame-retardant and high-temperature resistant modified plastic according to claim 4, characterized in that, The amount of polyethylene resin, acrylate malic acid, and dicumyl peroxide is 100 parts by weight, 6-15 parts by weight, and 0.12-0.3 parts by weight.

6. The flame-retardant and high-temperature resistant modified plastic according to claim 4, characterized in that, The temperature of sections 1-5 of the screw extruder is 140-185℃, and the screw speed is 40-60 r / min.

7. A processing method for the flame-retardant and high-temperature resistant modified plastic as described in any one of claims 1-6, characterized in that, The processing method includes: adding acrylate malic acid-grafted polyethylene and aluminum hydroxide to a mixer for a first mixing, then adding polyethylene resin, ethylene-vinyl acetate copolymer, melamine phosphate flame retardant, and antioxidant, mixing for a second time, extruding the material in a screw extruder, granulating, and then injection molding in an injection molding machine to obtain flame-retardant and high-temperature resistant modified plastic.

8. The processing method of the flame-retardant and high-temperature resistant modified plastic according to claim 7, characterized in that, The temperature for the first mixing is 60-75℃ and the time is 20-30 minutes; the time for the second mixing is 20-40 minutes.

9. The processing method of the flame-retardant and high-temperature resistant modified plastic according to claim 7, characterized in that, The temperature of sections 1-5 of the screw extruder is 140-190℃, and the screw speed is 100-150 r / min.

10. The processing method of the flame-retardant and high-temperature resistant modified plastic according to claim 7, characterized in that, The temperature of the injection molding machine is 180-190℃, and the pressure is 30-40MPa.

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