Method for modifying flame-retardant ethylene-vinyl acetate copolymer by sol-gel method

A technology of vinyl acetate and sol-gel method, which is applied in the field of flame retardant materials, can solve the problems of low bulk density of fumed silica, difficult uniform distribution and nano-dispersion of particles, and limited effect, so as to solve health and safety problems, flame retardant The effect of improving the flame retardant performance and improving the flame retardant efficiency

Active Publication Date: 2018-11-06
BEIJING INSTITUTE OF TECHNOLOGYGY +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the bulk density of fumed silica is low, it is difficult to add in high-filling polymers, it is difficult to realize twin-screw extrusion processing, it is difficult to achieve uniform distribution and nano-dispersion of particles, and health and safety problems caused by powder scattering.
A comparison of SiO 2 The effect of different adding methods on the performance of polyurethane, found that direct mixing at room temperature is not conducive to SiO 2 Dispersion, poor modification effect
At present, the method of surface modification on silica particles is widely used, but the effect is limited

Method used

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  • Method for modifying flame-retardant ethylene-vinyl acetate copolymer by sol-gel method
  • Method for modifying flame-retardant ethylene-vinyl acetate copolymer by sol-gel method
  • Method for modifying flame-retardant ethylene-vinyl acetate copolymer by sol-gel method

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] A method for modifying a flame-retardant ethylene-vinyl acetate copolymer by a sol-gel method, the components and their mass percentages are shown in the following table: (based on the total mass percentage as 100%)

[0025]

[0026] Specific steps are as follows:

[0027] (1) After mixing tetraethyl orthosilicate and distilled water at a ratio of 1:3, add co-solvent ethanol under stirring conditions, add hydrochloric acid to adjust the pH to 3.5, and stir to obtain a stable and transparent system, namely the sol.

[0028] (2) After the ethylene-vinyl acetate copolymer is dried in an oven for 4 hours, the ethylene-vinyl acetate copolymer is melt-extruded in a twin-screw extruder, and the sol is added to the melt through a hopper during the extrusion process , the temperature of the twin-screw extruder is 100 ° C ~ 140 ° C, the feeding frequency is 10 rpm, and the main engine frequency is 20 rpm; after the extruded melt is air-cooled, it is granulated by a granulator ...

Embodiment 2

[0033] Taking the total mass of the composite material as 100%, the components and mass percentages are as follows:

[0034]

[0035] The specific steps of the preparation method of ethylene-vinyl acetate copolymer flame-retardant composite material are as follows:

[0036] (1) After mixing ethyl orthosilicate and distilled water at a ratio of 1:6, add co-solvent ethanol under stirring conditions, add ammonia monohydrate to adjust the pH to 6, and stir to obtain a stable and transparent system, that is, the sol.

[0037] (2) After the ethylene-vinyl acetate copolymer is dried in an oven for 4 hours, the ethylene-vinyl acetate copolymer is melt-extruded in a twin-screw extruder, and the sol is added to the melt through a hopper during the extrusion process , the temperature of the twin-screw extruder is 100 ° C ~ 140 ° C, the feeding frequency is 8 rpm, and the frequency of the main engine is 18 rpm; after the extruded melt is air-cooled, it is granulated by a granulator to ...

Embodiment 3

[0042] Taking the total mass of the composite material as 100%, the components and mass percentages are as follows:

[0043]

[0044] The specific steps of the preparation method of ethylene-vinyl acetate copolymer flame-retardant composite material are as follows:

[0045] (1) After mixing ethyl orthosilicate and distilled water at a ratio of 1:6, add co-solvent ethanol under stirring conditions, add ammonia monohydrate to adjust the pH to 6, and stir to obtain a stable and transparent system, that is, the sol.

[0046] (2) After the ethylene-vinyl acetate copolymer is dried in an oven for 4 hours, the ethylene-vinyl acetate copolymer is melt-extruded in a twin-screw extruder, and the sol is added to the melt through a hopper during the extrusion process , the temperature of the twin-screw extruder is 130°C to 140°C, the feeding frequency is 8rpm, and the main engine frequency is 22rpm; after the extruded melt is air-cooled, it is granulated by a granulator to obtain sol-g...

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Abstract

The invention relates to a method for modifying a flame-retardant ethylene-vinyl acetate copolymer by a sol-gel method, and belongs to the technical field of flame-retardant materials. The method comprises the following steps of reacting and extruding by the sol-gel method, so as to prepare the ethylene-vinyl acetate copolymer/silicon dioxide master batch; melting and extruding the ethylene-vinylacetate copolymer, a compatilizer, an inorganic flame retardant, the ethylene-vinyl acetate copolymer/silicon dioxide master batch, a processing additive and other raw materials in a double-screw extruder; cutting particles, and performing injection molding, so as to obtain the ethylene-vinyl acetate nanometer flame-retardant composite material. The ethylene-vinyl acetate nanometer flame-retardantcomposite material has the advantages that the difficult-processing problem and the health problem due to adding of vapor-phase silicon dioxide are solved; the flame-retardant agent is well dispersedin the material, the heat release rate and smoke release amount of the composite material are smaller, the condensed phase is effectively promoted to form carbon, the flame-retardant property is effectively improved, and the good popularization and application value is realized.

Description

technical field [0001] The invention relates to a method for modifying a flame-retardant ethylene-vinyl acetate copolymer by a sol-gel method, and belongs to the technical field of flame-retardant materials. Background technique [0002] Ethylene-vinyl acetate copolymer (EVA) is produced by copolymerization of ethylene and vinyl acetate. Vinyl acetate is introduced into the molecular structure to achieve the purpose of reducing crystallinity, so that EVA has excellent elasticity, weather resistance, and filler and color masterbatch Compatibility of materials, and easier to process, so it is widely used in agriculture, automobile industry, wire and cable and other fields. However, EVA is flammable and produces molten dripping and a large amount of smoke when burning, which limits its various applications. All over the world, although halogenated flame retardants show excellent performance in flame retardant polymer materials, due to the fact that halogenated flame retardants...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08L23/08C08L23/06C08L83/04C08L51/06C08K13/02C08K3/36C08K3/22C08K3/26C08K3/02C08K3/34C08K5/3492C08J3/22
CPCC08J3/226C08J2323/08C08J2423/06C08J2423/08C08J2451/06C08J2483/04C08K3/346C08K3/36C08K5/34928C08K13/02C08K2003/026C08K2003/2224C08K2003/2227C08K2003/267C08K2201/011
Inventor 李定华杨荣杰吴凡程博阿尔贝托·弗拉舍乔万尼·卡米诺
Owner BEIJING INSTITUTE OF TECHNOLOGYGY
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