CN102924749B - A kind of ionic liquid type phosphate flame retardant and preparation method thereof - Google Patents

Abstract

式中R=C_nH_2n+1，n选自1、3或2-18之间的偶数；X选自Cl、Br、BF₄、PF₆或N(CF₃SO₂)₂。本发明阻燃剂分子中含有1-氧代-4-羟甲基-2,6,7-三氧杂-1-磷杂双环[2.2.2]辛烷（PEPA）骨架，集膨胀阻燃剂（IFR）的酸源和炭源于一体，并具有热稳定性高，成炭性能优越的特点。本发明阻燃剂在与多聚磷酸铵等外加气源复合时可组成一种新型IFR，该IFR不仅具有阻燃效率高的优点，而且与聚合物基体的相容性较好。The invention discloses an ionic liquid phosphate flame retardant and a preparation method thereof, wherein the structural formula of the ionic liquid phosphate flame retardant is as follows:

In the formula, R=C _n H _2n+1 , n is selected from 1, 3 or an even number between 2-18; X is selected from Cl, Br, BF ₄ , PF ₆ or N(CF ₃ SO ₂ ) ₂ . The flame retardant molecule of the present invention contains 1-oxo-4-hydroxymethyl-2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane (PEPA) skeleton, which integrates expansion and flame retardancy The acid source and carbon source of the agent (IFR) are integrated, and it has the characteristics of high thermal stability and excellent char formation performance. When the flame retardant of the present invention is compounded with an external gas source such as ammonium polyphosphate, a new type of IFR can be formed. The IFR not only has the advantages of high flame retardant efficiency, but also has good compatibility with the polymer matrix.

Description

A kind of ionic liquid type phosphate flame retardant and preparation method thereof

1. Technical field

The invention relates to a flame retardant and a preparation method thereof, in particular to a preparation method of an ionic liquid type phosphate flame retardant.

2. Background technology

In recent years, with the continuous development of science and technology, polymer materials have been widely used in the fields of national defense, construction, transportation, aviation, electrical appliances, and household furniture. However, most polymer materials are easy to burn and release a large amount of toxic smoke, which brings huge threats and losses to the safety of people's lives and properties. Therefore, it is of great significance to carry out flame retardant treatment on polymer materials.

Since the 1990s, intumescent flame retardant (IFR) has been considered as a promising flame retardant method due to its low smoke, low toxicity and superior anti-dripping properties, and has gradually become a polymer The focus of material flame retardant research field. When IFR works, it will form a protective intumescent carbon layer on the surface of the polymer, which can effectively block the transfer of heat and substances in the gas phase and condensed phase, so as to achieve the purpose of flame retardancy. An IFR system currently widely used is composed of ammonium polyphosphate (APP, acid source and gas source), pentaerythritol (PER, carbon source) and melamine (MEL, gas source). When the composition of APP, PER and MEL is appropriate, IFR will play a good synergistic flame retardant effect. However, when the IFR system is applied to flame retardant polymer materials, there are also problems such as relatively low flame retardant efficiency, poor compatibility with the polymer matrix, and poor thermal stability. In order to make the flame retardant performance of the material pass the UL-94 V-0 test, its addition amount is usually more than 30wt%, which will lead to the deterioration of the mechanical properties of the material.

3. Contents of the invention

The invention aims to provide an ionic liquid phosphate flame retardant and a preparation method thereof, and the technical problem to be solved is to improve the thermal stability of IFR and the compatibility with polymers.

The present invention utilizes efficient, water-resistant and temperature-resistant cage-type phosphate——1-oxo-4-hydroxymethyl-2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane ( PEPA) was used as a raw material to synthesize an ionic liquid phosphate flame retardant. The ionic liquid phosphate flame retardant can not only be used as the acid source and carbon source of IFR, but also can be used as a surface modifier to improve the compatibility between the flame retardant and the polymer matrix.

Ionic liquid type phosphate flame retardant of the present invention is characterized in that its structural formula is as follows:

In the formula, R=C _n H _2n+1 , n is selected from an even number between 1, 3 or 2-18;

X is selected from Cl, Br, BF ₄ , PF ₆ or N(CF ₃ SO ₂ ) ₂ .

The preparation method of ionic liquid type phosphoric acid ester flame retardant of the present invention is characterized in that following steps are operated:

a. Add 1-oxo-4-hydroxymethyl-2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane (PEPA) and solvent acetonitrile into the reactor, stir until large Part of the PEPA is dissolved, and then the haloacetyl halide is added dropwise at 0-40°C under the protection of nitrogen, and the temperature is raised to 40-80°C for 12-48 hours. After the reaction is completed, the solvent is distilled off under reduced pressure, and the intermediate is obtained after washing and drying. Body I; the molar ratio of the haloacetyl halide to PEPA is 1-2:1;

The structural formula of the haloacetyl halide is:

In the formula, Y is Cl or Br, that is, the haloacetyl halide is chloroacetyl chloride or bromoacetyl bromide.

The reaction process of step a is as follows:

Intermediate I

b. Dissolve the intermediate I in the solvent acetonitrile, add alkylimidazole, heat up to 40-80°C in a nitrogen atmosphere and react for 12-48 hours, filter after the reaction, the filter cake is washed and dried to obtain an anion as Y ^- ionic liquid phosphate flame retardant (abbreviated as [PCMIM]Y); the molar ratio of the alkylimidazole to the intermediate I is 1-2:1;

The structural formula of the alkylimidazole is:

In the formula, R=C _n H _2n+1 , n is an even number between 1, 3 or 2-18.

The reaction process of step b is as follows:

Intermediate I Target product

c. Dissolve the ionic liquid phosphate flame retardant ([PCMIM]Y) whose anion is Y ^- in the solvent acetonitrile, add the anion salt M ⁺ Z ^- , stir and react at room temperature for 12-48 hours, and the reaction ends After filtration, the filtrate is concentrated and dried to obtain an ionic liquid phosphate flame retardant (abbreviated as [PCMIM]Z) with an anion of ^Z- ; the mole of the anion salt M ⁺ Z ^- and [PCMIM]Y The ratio is 1-2:1.

The anion salt M ⁺ Z ⁻ is selected from NaBF ₄ , KBF ₄ , NH ₄ BF ₄ , NaPF ₆ , KPF ₆ , NH ₄ PF ₆ or LiN(CF ₃ SO ₂ ) ₂ .

The reaction process of step c is as follows:

target product

The present invention has the following advantages:

1. The ionic liquid phosphate ester flame retardant of the present invention has low halogen content, is beneficial to environmental protection, has good application prospects, and also adds a new variety to phosphorus-containing flame retardants.

2. The ionic liquid-type phosphate flame retardant of the present invention has the advantages of high thermal stability, excellent char-forming performance, and good compatibility with polymer matrix.

3. The ionic liquid phosphate flame retardant of the present invention contains 1-oxo-4-hydroxymethyl-2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane in the molecule (PEPA) skeleton, which integrates the acid source and carbon source of the intumescent flame retardant, can form a new type of IFR when it is combined with APP and other external gas sources. The compatibility of the matrix is better.

4. The preparation method of the ionic liquid type phosphate flame retardant of the present invention is simple, the process is mature, easy to control, and the yield of the obtained product is relatively high.

4. Description of drawings

Fig. 1 is the proton nuclear magnetic resonance spectrum of intermediate I in Example 1 of the present invention, wherein the deuterated reagent is DMSO-d ₆ , and the internal standard is TMS. It can be seen from Figure 1 that the structural formula of intermediate I is consistent with the expected structure, and the chemical shift of each hydrogen atom on intermediate I is as follows: δ ₁ =4.087(s, 2H, C-CH ₂ -OCO), δ ₂ =4.439 (s, 2H, _CH2 -Cl), _δ3 = 4.656 (d, 6H, PO-CH2 _- C).

Fig. 2 is the hydrogen nuclear magnetic resonance spectrum of the ionic liquid phosphate flame retardant ([PCMIM]Cl) in Example 1 of the present invention, wherein the deuterated reagent is DMSO-d ₆ , and the internal standard is TMS. It can be seen from Figure 2 that the structural formula of the target product [PCMIM]Cl is consistent with the expected structure, and the chemical shift of each hydrogen atom on [PCMIM]Cl is as follows: δ ₁ =3.925(s, 3H, N-CH ₃ ), δ ₂ =4.144(s, 2H, C-CH ₂ -OCO), δ ₃ =4.679(d, 6H, PO-CH ₂ -C), δ ₄ =5.334(s, 2H, OCO-CH ₂ -N), δ ₅ =7.759(s, 2H, N-CH-CH), δ ₆ =9.175(s, 1H, N-CH-N).

Figure 3 is the thermogravimetric analysis spectrum of the ionic liquid phosphate ester flame retardant ([PCMIM]Cl) in Example 1 of the present invention. The test conditions are: nitrogen atmosphere, heating rate 10°C/min, heating range 35-700 ℃. It can be seen from Figure 3 that the initial decomposition temperature of [PCMIM]Cl is 265.5°C (based on 5% mass loss), and its carbon residue at 700°C is as high as 39.0wt%, which shows that [PCMIM]Cl not only has a relatively High thermal stability and good self-charging ability.

Figure 4 is a scanning electron microscope photo of the flame-retardant PP section before and after the addition of the ionic liquid phosphate flame retardant ([PCMIM]Cl) in Example 1 of the present invention, where (A) PP:APP=70:30; (B) PP:APP:[PCMIM]Cl=70:22:8. It can be seen from Figure 4 that when the total amount of flame retardant is 30wt%, the compatibility between the APP/[PCMIM]Cl composite flame retardant and the PP matrix is significantly improved compared with the single flame retardant APP. This shows that [PCMIM]Cl has a more obvious compatibilizing effect when applied to PP intumescent flame retardancy.

5. Specific implementation

The present invention will describe the technical solutions of the present invention in more detail through the following specific examples, but the present invention is not limited to the following examples.

Example 1:

1. In the 500mL three-necked flask equipped with magnetic stirring, reflux condenser, dropping funnel and _N2 ball, add 27.01g (0.15mol) PEPA and 100mL acetonitrile, start stirring, the reaction temperature rises to 40 ° C, and then Slowly add 33.89g (0.30mol) chloroacetyl chloride dropwise in the time of 1h, after the completion of the dropwise addition of chloroacetyl chloride, the temperature is raised to 80°C to continue the reaction for 24h. After drying in a vacuum oven at 70°C for 12 h, intermediate I was obtained with a yield of 79%.

2. Add 25.66g (0.15mol) of intermediate I, 9.85g (0.12mol) of 1-methylimidazole and 100mL of acetonitrile into a 500mL three-necked flask equipped with magnetic stirring, reflux condenser and _N2 bulb, and start stirring. Heat up to 80 DEG C and react for 24 hours, filter after the reaction is over, wash the filter cake with acetonitrile and dry it in a vacuum oven at 70 DEG C for 12 hours to obtain an ^ionic liquid phosphate flame retardant (abbreviated as [ PCMIM]Cl), the yield is 98%, and the structural formula is as follows:

3. Using ethanol as a solvent, wet compound the flame retardant [PCMIM]Cl synthesized in step 2 with APP at a mass ratio of 1:5, evaporate the solvent under reduced pressure, and dry in vacuum to obtain a composite flame retardant. Then the composite flame retardant is mixed with polypropylene (S1003) in an addition amount of 30wt% in a 175°C Huck torque rheometer at a speed of 30rpm for 10min to obtain a flame-retardant polypropylene whose oxygen index can reach 31.8 %, and passed the UL-94 V-0 level test.

Example 2:

1. In a 500mL flask equipped with N ₂ balls, add 16.94g (0.05mol) of ionic liquid phosphate flame retardant ([PCMIM]Cl) with Cl ^- anion, 6.59g (0.06mol) of NaBF ₄ and 100mL of acetonitrile, stirred at room temperature for 24h, after the reaction was completed, filtered and the filtrate was concentrated, and dried in vacuum at 70°C for 12h to obtain an ionic liquid phosphate flame retardant with BF ₄ ^- (abbreviated as [PCMIM] BF ₄ ), the structural formula is as follows:

2. Using ethanol as a solvent, wet compound the flame retardant [PCMIM]BF ₄ synthesized in step 1 with APP at a mass ratio of 1:5, evaporate the solvent under reduced pressure, and dry in vacuum to obtain a composite flame retardant. Then the composite flame retardant is mixed with polypropylene (S1003) in an addition amount of 30wt% in a 175°C Huck torque rheometer at a speed of 30rpm for 10min to obtain a flame-retardant polypropylene whose oxygen index can reach 32.0 %, and passed the UL-94 V-0 level test.

Example 3:

1. In a 500mL flask equipped with N ₂ balls, add 16.94g (0.05mol) of ionic liquid phosphate flame retardant ([PCMIM]Cl) whose anion is Cl ^- , 11.04g (0.06mol) of KPF ₆ and 100mL of acetonitrile, stirring and reacting at room temperature for 24h, after ^the reaction was completed, filtered and the filtrate was concentrated, and dried in a vacuum oven at 70°C for 12h to obtain an ionic liquid phosphate flame retardant with _PF6- (abbreviated as [PCMIM]PF ₆ ), the structural formula is as follows:

2. Using ethanol as a solvent, carry out wet compounding of the flame retardant [PCMIM]PF ₆ synthesized above and APP at a mass ratio of 1:5, evaporate the solvent under reduced pressure, and dry in vacuum to obtain a composite flame retardant. Then the composite flame retardant is mixed with polypropylene (S1003) in an addition amount of 30wt% in a Hack torque rheometer at 175°C at a speed of 30rpm for 10min to obtain a flame-retardant polypropylene whose oxygen index can reach 32.2 %, and passed the UL-94 V-0 level test.

Example 4:

1. In a 500mL flask equipped with N ₂ balls, add 16.94g (0.05mol) of ionic liquid phosphate flame retardant whose anion is Cl ^- , 17.23g (0.06mol) of LiN(CF ₃ SO ₂ ) ₂ and 100mL of acetonitrile, stirred at room temperature for 24h, after the reaction was completed, filtered and the filtrate was concentrated, dried in a vacuum oven at 70°C for 12h, and the anion was (CF ₃ SO ₂ ) ₂ N ^- ionic liquid type phosphate barrier Combustion agent (abbreviated as [PCMIM]NTf ₂ ), the structural formula is as follows:

2. Using ethanol as a solvent, wet compound the flame retardant [PCMIM]NTf ₂ synthesized above with APP at a mass ratio of 1:5, evaporate the solvent under reduced pressure, and dry in vacuum to obtain a composite flame retardant. Then the composite flame retardant is mixed with polypropylene (S1003) in an addition amount of 30wt% in a 175°C Huck torque rheometer at a speed of 30rpm for 10min to obtain a flame-retardant polypropylene whose oxygen index can reach 31.5 %, and passed the UL-94 V-0 level test.

Claims (2)

1. An ionic liquid type phosphoric acid ester flame retardant is characterized in that its structural formula is as follows:

In the formula, R=C _n H _2n+1 , n is selected from an even number between 1, 3 or 2-18; X is selected from Cl, Br, BF ₄ , PF ₆ or N(CF ₃ SO ₂ ) ₂ . 2. a kind of preparation method of ionic liquid type phosphoric acid ester flame retardant as claimed in claim 1 is characterized in that operating in the following steps: a. Add 1-oxo-4-hydroxymethyl-2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane and solvent acetonitrile into the reactor, under nitrogen protection at 0 Add haloacetyl halide dropwise at -40°C, then raise the temperature to 40-80°C for 12-48 hours, after the reaction, distill off the solvent under reduced pressure, obtain intermediate I after washing and drying; the haloacetyl halide and PEPA The molar ratio is 1-2:1; The structural formula of the haloacetyl halide is:

, In the formula, Y is Cl or Br; b. Dissolve the intermediate I in the solvent acetonitrile, add alkylimidazole, heat up to 40-80°C in a nitrogen atmosphere and react for 12-48 hours, filter after the reaction, wash and dry the filter cake to obtain an anion as Y ^- ionic liquid phosphate flame retardant; the molar ratio of the alkylimidazole to the intermediate I is 1-2:1; The structural formula of the alkylimidazole is: , In the formula, R=C _n H _2n+1 , n is an even number between 1, 3 or 2-18; c. Dissolve the ionic liquid phosphate flame retardant whose anion is Y ^- in the solvent acetonitrile, add the anion salt M ⁺ Z ^- , stir and react at room temperature for 12-48 hours, filter after the reaction, and concentrate the filtrate , after drying, the ionic liquid phosphate flame retardant that the anion is ^Z- is obtained; the molar ratio of the anion salt M ^{+ Z-} to the ionic liquid phosphate flame retardant that the anion is ^Y- is 1 -2:1; The anion salt M ⁺ Z ⁻ is selected from NaBF ₄ , KBF ₄ , NH ₄ BF ₄ , NaPF ₆ , KPF ₆ , NH ₄ PF ₆ or LiN(CF ₃ SO ₂ ) ₂ .

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