阅读说明：本技术 环保塑料阻燃剂、制备方法及其在塑料中的应用 (Environment-friendly plastic flame retardant, preparation method and application thereof in plastics ) 是由 肖艳芳 于 2020-05-19 设计创作，主要内容包括：本发明公开了一种环保塑料阻燃剂、制备方法及其在塑料中的应用,所述环保塑料阻燃剂的制备方法,包括下述步骤：步骤一：磷系阻燃剂与水混合,得到分散液A；步骤二：将壳聚糖溶液与分散液A混合,离心、过滤,洗涤,再加水混合,得到分散液B；步骤三：将海藻酸溶液与分散液B混合,离心、过滤,洗涤,真空干燥,研磨成粉。本发明在水溶液体系中以磷系阻燃剂为核心,与壳聚糖、海藻酸通过自组装在磷系阻燃剂之上形成壳体得到环保塑料阻燃剂；能够有效防止可燃物气体的逸出、有效隔绝了塑料特别是PET的热氧侵蚀,抑制塑料分解燃烧,提高阻燃性能。(The invention discloses an environment-friendly plastic flame retardant, a preparation method and application thereof in plastics, wherein the preparation method of the environment-friendly plastic flame retardant comprises the following steps: the method comprises the following steps: mixing a phosphorus flame retardant with water to obtain a dispersion liquid A; step two: mixing the chitosan solution with the dispersion liquid A, centrifuging, filtering, washing, and adding water for mixing to obtain a dispersion liquid B; step three: mixing the alginic acid solution with the dispersion liquid B, centrifuging, filtering, washing, vacuum drying, and grinding into powder. The invention takes phosphorus flame retardant as core in aqueous solution system, and forms shell with chitosan and alginic acid through self-assembly on the phosphorus flame retardant to obtain environment-friendly plastic flame retardant; can effectively prevent the escape of combustible gas, effectively isolate the hot oxygen erosion of plastics, particularly PET, inhibit the decomposition and combustion of the plastics and improve the flame retardant property.)

1. The preparation method of the environment-friendly plastic flame retardant is characterized by comprising the following steps of:

the method comprises the following steps: mixing a phosphorus flame retardant with water to obtain a dispersion liquid A;

step two: mixing the chitosan solution with the dispersion liquid A, centrifuging, filtering, washing, and adding water for mixing to obtain a dispersion liquid B;

step three: mixing the alginic acid solution with the dispersion liquid B, centrifuging, filtering, washing, vacuum drying, and grinding into powder.

2. The method for preparing the environment-friendly plastic flame retardant according to claim 1, characterized by comprising the following steps:

the method comprises the following steps: mixing a phosphorus flame retardant with water, wherein the mass ratio of the phosphorus flame retardant to the water is (1-50): 400, and obtaining a dispersion liquid A;

step two: mixing a chitosan solution and the dispersion liquid A, wherein the mass ratio of the phosphorus flame retardant to the chitosan solution is (1-50): 200, centrifuging, filtering, washing, adding water, and mixing to obtain a dispersion liquid B, wherein the mass ratio of the phosphorus flame retardant to the water is (1-50): 400;

step three: mixing the alginic acid solution with the dispersion liquid B, wherein the mass ratio of the phosphorus flame retardant to the alginic acid solution is (1-50): 200, centrifuging, filtering, washing, vacuum drying, and grinding into powder.

3. The method for preparing the environment-friendly plastic flame retardant according to claim 1 or 2, wherein the phosphorus-based flame retardant is at least one of ammonium polyphosphate, tricresyl phosphate, dimethyl methylphosphonate, 2-carboxyethyl (phenyl) phosphinic acid and zinc diethylphosphinate.

4. An environment-friendly plastic flame retardant, which is prepared by the method of any one of claims 1 to 3.

5. The preparation method of the environment-friendly plastic flame retardant is characterized by comprising the following steps of:

adding the environment-friendly plastic flame retardant of claim 4 into ethylene glycol, wherein the mass ratio of the environment-friendly plastic flame retardant to the ethylene glycol is (1-10): 200, and uniformly stirring to obtain a dispersion liquid W;

adding the dispersion liquid W, terephthalic acid and ethylene glycol antimony into a reaction kettle for mixing, wherein the molar ratio of the terephthalic acid to the ethylene glycol is 1 (1-1.33); the mass ratio of the ethylene glycol antimony to the terephthalic acid is (0.5-5) 5000; carrying out esterification reaction;

after esterification, vacuumizing, carrying out pre-polycondensation reaction, and then carrying out polycondensation reaction; cooling, washing, vacuum drying and grinding.

6. The method for preparing the environment-friendly plastic flame retardant according to claim 5, characterized by comprising the following steps:

adding the environment-friendly plastic flame retardant of claim 4 into ethylene glycol, wherein the mass ratio of the environment-friendly plastic flame retardant to the ethylene glycol is (1-10): 200, ultrasonic stirring is carried out at 20-50 ℃ for 5-10 min, the ultrasonic frequency is 20-80 kHz, and the stirring speed is 100-150 rpm, so as to obtain a dispersion liquid W;

adding the dispersion liquid W, terephthalic acid and ethylene glycol antimony into a reaction kettle for mixing, wherein the molar ratio of the terephthalic acid to the ethylene glycol is 1 (1-1.33); the mass ratio of the ethylene glycol antimony to the terephthalic acid is (0.5-5) 5000; introducing nitrogen into the reaction kettle, opening circulating water, performing esterification reaction, controlling the esterification temperature to be 245-265 ℃, the esterification pressure to be 0.10-0.20 MPa, the rotating speed of a stirring paddle to be 25-45 r/min, and the esterification time to be 2.5-5.5 h;

after the esterification is finished, vacuumizing, and carrying out pre-polycondensation reaction for 50-85 min at the pressure of 2650-3300 Pa and the temperature of 270-280 ℃;

performing polycondensation reaction for 1.5-3.5 h at the temperature of 280-310 ℃ and under the vacuum pressure of 45-85 Pa;

cooling at room temperature, carrying out suction filtration and washing by using absolute ethyl alcohol, carrying out vacuum drying for 4-6 h at the temperature of 80-100 ℃, and grinding.

7. An environment-friendly plastic flame retardant, which is characterized by being prepared by the method of claim 5 or 6.

8. Use of the environmentally friendly plastic flame retardant of claim 4 or 7 in plastics.

9. The use of the environmentally friendly plastic flame retardant of claim 8 in plastics, wherein: the plastic is PET.

10. A flame retardant plastic characterized by: comprising 0.2 to 10 wt.% of an environmentally friendly plastic flame retardant according to claim 4 or 7.

Technical Field

The invention belongs to the technical field of high polymer materials, and particularly relates to an environment-friendly plastic flame retardant, a preparation method and application thereof in plastics.

Background

Most plastics are flammable. With the wide application of plastics in the aspects of buildings, furniture, traffic, aviation, aerospace, electrical appliances and the like, the improvement of the flame retardance of plastics has become a very urgent subject. The addition of plastic flame retardant into plastic becomes a mainstream choice.

The plastic flame retardant mainly comprises halogen flame retardant, phosphorus flame retardant and other flame retardants.

The halogen flame retardant is the earliest flame retardant for resin, but the halogen flame retardant generates carcinogenic substances such as corrosive gas hydrogen halide and polybrominated dibenzofuran during combustion, thereby seriously damaging human health.

Phosphorus is one of the most effective flame retardant elements for resin, and various phosphorus flame retardants are used in the field of resin flame retardance and can be divided into inorganic phosphorus flame retardants and organic phosphorus flame retardants; the inorganic phosphorus flame retardant mainly comprises red phosphorus, phosphate and the like; the organic phosphorus flame retardant mainly includes phosphoric acid esters, phosphorous acid esters, phosphonic acid esters, organic phosphinic acid metal salts, and the like.

However, phosphorus flame retardants also have disadvantages such as high volatility, poor thermal stability, and poor compatibility with resins. In addition, the plastic flame retardant is often added in large amounts, further affecting the flowability, processability and other physicochemical properties of the resin.

Disclosure of Invention

In view of the defects of the prior art, one of the technical problems to be solved by the present invention is to provide a preparation method of an environment-friendly plastic flame retardant.

The invention takes phosphorus flame retardant as core in aqueous solution system, and forms shell with chitosan and alginic acid through self-assembly on the phosphorus flame retardant to obtain environment-friendly plastic flame retardant; the shell formed by chitosan and alginic acid increases the carbon content on the surface of the phosphorus flame retardant, the polyhydroxy structure in chitosan and alginic acid is easy to dehydrate to form carbon residue under the high temperature condition, and phosphoric acid, polyphosphate and the like in the phosphorus flame retardant further accelerate the dehydration and carbonization effects, so that a more compact carbon residue layer is formed, the protective carbon layer prevents the escape of combustible gas, effectively isolates the hot oxygen corrosion of plastics, particularly PET, inhibits the decomposition and combustion of the plastics, and improves the flame retardant property.

The specific technical scheme is as follows:

a preparation method of an environment-friendly plastic flame retardant comprises the following steps:

the method comprises the following steps: mixing a phosphorus flame retardant with water to obtain a dispersion liquid A;

step two: mixing the chitosan solution with the dispersion liquid A, centrifuging, filtering, washing, and adding water for mixing to obtain a dispersion liquid B;

step three: mixing the alginic acid solution with the dispersion liquid B, centrifuging, filtering, washing, vacuum drying, and grinding into powder.

Preferably, the preparation method of the environment-friendly plastic flame retardant comprises the following steps:

the method comprises the following steps: mixing a phosphorus flame retardant with water, wherein the mass ratio of the phosphorus flame retardant to the water is (1-50): 400, and obtaining a dispersion liquid A;

step two: mixing a chitosan solution and the dispersion liquid A, wherein the mass ratio of the phosphorus flame retardant to the chitosan solution is (1-50): 200, centrifuging, filtering, washing, adding water, and mixing to obtain a dispersion liquid B, wherein the mass ratio of the phosphorus flame retardant to the water is (1-50): 400;

step three: mixing the alginic acid solution with the dispersion liquid B, wherein the mass ratio of the phosphorus flame retardant to the alginic acid solution is (1-50): 200, centrifuging, filtering, washing, vacuum drying, and grinding into powder.

Preferably, the preparation method of the environment-friendly plastic flame retardant comprises the following steps:

the method comprises the following steps: adding a phosphorus flame retardant into deionized water, and stirring for 5-30 min at a stirring speed of 100-150 rpm, wherein the mass ratio of the phosphorus flame retardant to the deionized water is (1-50): 400, so as to obtain a dispersion A;

step two: adding a chitosan solution into the dispersion liquid A at a speed of 0.5-5 mL/min, stirring for 1-30 min at a stirring speed of 100-150 rpm, wherein the mass ratio of the phosphorus flame retardant to the chitosan solution is (1-50): 200, centrifuging, filtering, washing with deionized water for 1-3 times, and adding deionized water, wherein the mass ratio of the phosphorus flame retardant to the deionized water is (1-50): 400, so as to obtain a dispersion liquid B;

step three: adding the alginic acid solution into the dispersion liquid B at a speed of 0.5-5 mL/min, stirring for 1-30 min at a stirring speed of 100-150 rpm, wherein the mass ratio of the phosphorus flame retardant to the alginic acid solution is (1-50): 200, centrifuging, filtering, washing with deionized water for 1-3 times, vacuum drying at 50-100 ℃ for 6-18 h, and grinding into powder.

Preferably, the chitosan solution is prepared by the following method: adding chitosan into 0.2-2 wt% acetic acid aqueous solution, stirring for 5-30 min at the stirring speed of 100-150 rpm, wherein the mass ratio of the chitosan to the 0.2-2 wt% acetic acid aqueous solution is (1-10): 200.

Preferably, the alginic acid solution is prepared by the following method: adding alginic acid into 0.2-2 wt% of ammonia water solution, and stirring for 5-30 min at a stirring speed of 100-150 rpm, wherein the mass ratio of the alginic acid to the 0.2-2 wt% of ammonia water solution is (1-10): 200.

Preferably, the phosphorus flame retardant is at least one of ammonium polyphosphate, tricresyl phosphate, dimethyl methylphosphonate, 2-carboxyethyl (phenyl) phosphinic acid and zinc diethylphosphinate.

More preferably, the phosphorus flame retardant is a mixture of ammonium polyphosphate and tricresyl phosphate, and the mass ratio of the ammonium polyphosphate to the tricresyl phosphate is (0.1-10): 1.

A large number of experiments show that the compound of ammonium polyphosphate and tricresyl phosphate is adopted as the core of the core-shell type composite phosphorus flame retardant, so that the synergistic effect is realized, and the flame retardant property is further improved. The core-shell type composite phosphorus flame retardant taking ammonium polyphosphate and trimethyl benzene phosphate as cores is used as the center of different sites to dehydrate and form carbon at high temperature in a PET system, and the core-shell type composite phosphorus flame retardant and the site center complement each other, so that the protective carbon layer is more compact and stable, and the inhibition effect is stronger.

More preferably, the phosphorus flame retardant is a mixture of ammonium polyphosphate, tricresyl phosphate and zinc diethylphosphinate, and the mass ratio of the ammonium polyphosphate to the tricresyl phosphate to the zinc diethylphosphinate is (0.1-10) to 1 (0.1-10).

The second technical problem to be solved by the invention is to provide an environment-friendly plastic flame retardant prepared by the method. The environment-friendly plastic flame retardant is a core-shell type composite phosphorus flame retardant.

The invention further improves the dispersibility and compatibility of the phosphorus flame retardant in a plastic such as a PET system by preparing the double-shell type composite phosphorus flame retardant, the newly-added shell enables a flexible chain to be formed between the wrapped phosphorus flame retardant core and the plastic such as PET, the interface combination effect of the phosphorus flame retardant core and the plastic is increased, in addition, the stability of the phosphorus flame retardant is enhanced, the flame retardant property of the plastic such as PET resin is further improved, and the mechanical property of the plastic such as PET resin is also improved.

Specifically, the preparation method of the environment-friendly plastic flame retardant comprises the following steps:

adding the prepared environment-friendly plastic flame retardant, namely the core-shell type composite phosphorus flame retardant into ethylene glycol, wherein the mass ratio of the core-shell type composite phosphorus flame retardant to the ethylene glycol is (1-10): 200, and uniformly stirring to obtain a dispersion liquid W;

adding the dispersion liquid W, phthalic acid and ethylene glycol antimony into a reaction kettle for mixing, wherein the molar ratio of the terephthalic acid to the ethylene glycol is 1 (1-1.33); the mass ratio of the ethylene glycol antimony to the terephthalic acid is (0.5-5) 5000; carrying out esterification reaction;

after esterification, vacuumizing, carrying out pre-polycondensation reaction, and carrying out polycondensation reaction for 1.5-3.5 h; cooling, washing, vacuum drying and grinding.

Preferably, the preparation method of the environment-friendly plastic flame retardant comprises the following steps:

adding the prepared environment-friendly plastic flame retardant, namely the core-shell type composite phosphorus flame retardant into ethylene glycol, wherein the mass ratio of the core-shell type composite phosphorus flame retardant to the ethylene glycol is (1-10): 200, ultrasonic stirring is carried out at 20-50 ℃ for 5-10 min, the ultrasonic frequency is 20-80 kHz, and the stirring speed is 100-150 rpm, so as to obtain dispersion liquid W; adding the dispersion liquid W, phthalic acid and ethylene glycol antimony into a reaction kettle for mixing, wherein the molar ratio of the terephthalic acid to the ethylene glycol is 1 (1-1.33); the mass ratio of the ethylene glycol antimony to the terephthalic acid is (0.5-5) 5000; introducing nitrogen into the reaction kettle, opening circulating water, performing esterification reaction, controlling the esterification temperature to be 245-265 ℃, the esterification pressure to be 0.10-0.20 MPa, the rotating speed of a stirring paddle to be 25-45 r/min, and the esterification time to be 2.5-5.5 h; after the esterification is finished, vacuumizing, and carrying out pre-polycondensation reaction for 50-85 min at the pressure of 2650-3300 Pa and the temperature of 270-280 ℃; performing polycondensation reaction for 1.5-3.5 h at the temperature of 280-310 ℃ and under the vacuum pressure of 45-85 Pa; cooling at room temperature, carrying out suction filtration and washing by using absolute ethyl alcohol, carrying out vacuum drying for 4-6 h at the temperature of 80-100 ℃, and grinding.

The invention also provides an environment-friendly plastic flame retardant prepared by the method. The environment-friendly plastic flame retardant is a double-shell type composite phosphorus flame retardant.

The invention aims to solve the technical problem of providing the application of the environment-friendly plastic flame retardant in plastics.

The invention also provides flame-retardant plastic, which comprises 0.2-10 wt% of the environment-friendly plastic flame retardant.

The invention has the beneficial effects that: the invention adopts the environment-friendly plastic flame retardant, namely the core-shell type composite phosphorus flame retardant, to improve the flame retardant property of plastics such as PET resin; the core-shell type composite phosphorus flame retardant is prepared by taking a phosphorus flame retardant as a core in an aqueous solution system and forming a shell on the phosphorus flame retardant through self-assembly of the phosphorus flame retardant, chitosan and alginic acid; the shell formed by chitosan and alginic acid increases the carbon content on the surface of the phosphorus flame retardant, the polyhydroxy structure in chitosan and alginic acid is easy to dehydrate to form carbon residue under the high temperature condition, and phosphoric acid, polyphosphate and the like in the phosphorus flame retardant further accelerate the dehydration and carbonization actions, so that a more compact carbon residue layer is formed, the protective carbon layer prevents the escape of combustible gas, effectively isolates the hot oxygen corrosion of plastics such as PET, inhibits the decomposition and combustion of plastics such as PET, and improves the flame retardant property; however, the addition of the flame retardant can enhance the flame retardant property of plastics such as PET and simultaneously cause the reduction of mechanical property to a certain extent, the invention further improves the dispersibility and compatibility of the phosphorus flame retardant in plastics such as PET by preparing the double-shell type composite phosphorus flame retardant, the newly-added shell enables a flexible chain to be formed between the wrapped phosphorus flame retardant core and the plastics such as PET, the interface combination effect between the phosphorus flame retardant core and the plastics is increased, in addition, the stability of the phosphorus flame retardant is also enhanced, the flame retardant property of the plastics such as PET resin is further improved, and the mechanical property of the plastics such as PET resin is also improved.

Detailed Description

The specific parameters of some substances in the embodiment of the invention are as follows:

terephthalic acid, CAS: 100-21-0, purity: 99% of the total amount of the crude oil obtained from Nantong Runfeng petrochemical Co.

Ethylene glycol, CAS: 107-21-1, purity: 99.9% of the total weight of the product, purchased from Shandong Chuangying chemical Co.

Ethylene glycol antimony, CAS: 29736-75-2, purity: 98% of the total amount of the total amounts of the.

Ammonium polyphosphate, CAS: 14728-39-3, P content: 31-32 wt% and DP >1000, and is purchased from Jinying Tai chemical Co., Ltd.

Tricresyl phosphate, CAS: 1330-78-5, purity: 99.5% of the total nutrient, which is purchased from chemical Limited company of Tianjian chemical industry.

Chitosan, CAS: 9012-76-4, the degree of deacetylation is more than or equal to 95%, the viscosity is 50-200 mpa.s, and the product is purchased from Dalian Meilun biotechnology Limited.

Alginic acid, CAS: 9005-32-7, from brown algae, available from Shanghai Ji to Biochemical technology, Inc.

Comparative example 1

The PET resin consists of the following raw materials: terephthalic acid, ethylene glycol, a catalyst;

the molar ratio of the terephthalic acid to the ethylene glycol is 1: 1.15;

the mass ratio of the catalyst to the terephthalic acid is 1.37:5000, and the catalyst is ethylene glycol antimony.

The PET resin is prepared by the following method:

y1 esterification stage: adding terephthalic acid, ethylene glycol and a catalyst into a reaction kettle, mixing, introducing nitrogen into the reaction kettle, opening circulating water, performing esterification reaction, controlling the esterification temperature to be 252 ℃, the esterification pressure to be 0.15MPa, the rotating speed of a stirring paddle to be 35r/min, and the esterification time to be 3.2 h;

y2 prepolymerization stage: after the esterification is finished, vacuumizing is started, and the pre-polycondensation reaction is carried out for 58min at the pressure of 2750Pa and the temperature of 272 ℃;

y3 polycondensation stage: and carrying out polycondensation reaction for 1.6h at the temperature of 283 ℃ and under the vacuum pressure of 68Pa to obtain the flame-retardant PET resin.