METHOD FOR PREPARING HALOGEN-FREE LOW-SMOKE INTRINSIC FLAME-RETARDANT NYLON 66 COMPOSITE MATERIAL

Abstract

The present invention discloses a method for preparing a halogen-free low-smoke intrinsic flame-retardant nylon 66 composite material, which is implemented according to a conventional preparation process by taking an organic acid-modified metal hydroxide as a flame retardant. According to the present invention, an organic acid containing flame-retardant elements such as P, N and S is used for carrying out reactive modification on the metal hydroxide, so that the agglomeration behavior of the metal hydroxide in a polymer is effectively reduced, the compatibility between the flame retardant and nylon 66 is improved. Meanwhile, a series of flame-retardant functional groups such as P, N and S are introduced, so that the flame retardancy of the nylon 66 is greatly improved, the smoke suppression effect is achieved to a certain extent. Therefore, the prepared intrinsic nylon 66 composite material has desirable flame retardancy (an oxygen index can reach 25.8) and low smoke effect.

Claims

1. A method for preparing a halogen-free low-smoke intrinsic flame-retardant nylon 66 composite material, wherein the composite material is implemented according to a conventional preparation process by taking an organic acid-modified metal hydroxide as a flame retardant.

2. The method for preparing a halogen-free low-smoke intrinsic flame-retardant nylon 66 composite material according to claim 1, wherein a process for preparing the flame retardant by using the organic acid-modified metal hydroxide comprises: ultrasonically dispersing the metal hydroxide in distilled water, adding an organic acid, heating and stirring at 60-100 C. for reaction for 5-8 h; after the solvent is removed by rotary evaporation, drying the mixture for 20-24 h at 60-100 C. to obtain an organic-modified inorganic flame retardant.

3. The method for preparing a halogen-free low-smoke intrinsic flame-retardant nylon 66 composite material according to claim 2, wherein the metal hydroxide is aluminum hydroxide, magnesium hydroxide and calcium hydroxide.

4. The method for preparing a halogen-free low-smoke intrinsic flame-retardant nylon 66 composite material according to claim 2, wherein the organic acid is 2-carboxyethyl(phenyl)phosphinic acid, phenylphosphonic acid, ethylenediamine tetra(methylene phosphonic acid) or sulfanilic acid.

5. The method for preparing a halogen-free low-smoke intrinsic flame-retardant nylon 66 composite material according to claim 2, wherein the mass ratio of the metal hydroxide to the organic acid is (1:2)-(1:8).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG. 1 is an infrared absorption spectrum curve of organic functionalization of inorganic particle magnesium hydroxide;

[0024] FIG. 2 is an SEM graph of organic functionalization of inorganic particle magnesium hydroxide;

[0025] FIG. 3 is an infrared absorption spectrum curve of flame-retardant nylon 66;

[0026] FIG. 4 is a graph showing the total heat release of nylon 66 when different proportions of flame retardant are added; and

[0027] FIG. 5 is a graph showing the heat release rate of nylon 66 when different proportions of flame retardant are added.

DETAILED DESCRIPTION

[0028] The preparation and flame-retardant properties of a halogen-free low-smoke flame-retardant nylon 66 composite material of the present invention are further explained by specific embodiments.

Embodiment 1

[0029] (1) Preparation of a modified flame retardant: 2.9 g of magnesium hydroxide was dissolved in a round-bottom flask containing 100 mL distilled water, and ultrasonic treatment was performed for 30 min; 10.7 g of 2-carboxyethyl(phenyl)phosphinic acid was added into the flask, magnetic stirring was carried out at 100 C. for 5 h, the solvent was removed by rotary evaporation, and drying was carried out at 80 C. for 24 h to obtain a 2-carboxyethyl(phenyl)phosphinic acid-modified magnesium hydroxide flame retardant.

[0030] (2) Synthesis of a halogen-free low-smoke intrinsic flame-retardant nylon 66: 500 g of nylon 66 salt was taken and prepared into a 60% salt solution by using 333 mL of distilled water, and 1.625 g of adipic acid was added to adjust the pH of the solution to about 7.6; 8 g of modified magnesium hydroxide flame retardant synthesized above was taken and dispersed in the distilled water, 4 g of 1,6-hexanediamine was added to adjust the pH to about 7.6; then the two solutions were added in a high-temperature and high-pressure reaction kettle, nitrogen was introduced into the reaction kettle, and air in the system was discharged. After gas replacement was performed three times, the pressure P in the system was kept at 0.3 MPa for 10-20 min. If the gas pressure was not reduced, it was proved that the air tightness of the system was good. Stirring and heating were performed, the stirring speed was 81 r/min, and I was equal to 0.84 A. When the system pressure P rose to 1.75-1.85 MPa, pre-polycondensation was carried out for 1-1.5 h, air was discharged to reduce the system pressure P to 0 within 30-60 min, and vacuumizing was performed to maintain the system under vacuum condition for 5-30 min. The rotating speed was 70-80 r/min, I was equal to 0.77-0.80 A, and stirring was stopped; 0.3-0.5 MPa of nitrogen gas 5was introduced, and the material stood for 8-30 min and then was discharged to obtain a halogen-free low-smoke intrinsic flame-retardant nylon 66 composite material.

[0031] (3) Flame-retardant properties of the intrinsic flame-retardant nylon 66 composite material: [0032] LOI=25.8%; THR=93.8 MJ/m.sup.2, PHRR=784.6 kW/m.sup.2, and TSP=6.1 m.sup.2.

Embodiment 2

[0033] (1) Preparation of a modified flame retardant: 3.9 g of aluminum hydroxide was dissolved in a round-bottom flask containing 100 mL distilled water, and ultrasonic treatment was performed for 30 min; 8.66 g of sulfanilic acid was added into the flask, magnetic stirring was carried out at 90 C. for 5 h, the solvent was removed by rotary evaporation, and drying was carried out at 80 C. for 24 h to obtain a sulfanilic acid-modified aluminum hydroxide flame retardant.

[0034] (2) Synthesis of a halogen-free low-smoke intrinsic flame-retardant nylon 66: The added flame retardant was the sulfanilic acid-modified aluminum hydroxide flame retardant, and others were the same as those of Embodiment 1.

[0035] (3) Flame-retardant properties of the intrinsic flame-retardant nylon 66 composite material: [0036] LOI=24.9%; THR=98.3 MJ/m.sup.2, PHRR=860.5 kW/m.sup.2, and TSP=8.3 m.sup.2.

[0037] Embodiment 3

[0038] (1) Preparation of a modified flame retardant: organic functionalization of magnesium hydroxide: 2.9 g of magnesium hydroxide was dissolved in a round-bottom flask containing 100 mL distilled water, and ultrasonic treatment was performed for 30 min; 8.66 g of sulfanilic acid was added into the flask, magnetic stirring was carried out at 90 C. for 5 h, the solvent was removed by rotary evaporation, and drying was carried out at 80 C. for 24 h to obtain a sulfanilic acid-modified magnesium hydroxide flame retardant.

[0039] (2) Synthesis of a halogen-free low-smoke intrinsic flame-retardant nylon 66: The added flame retardant was the sulfanilic acid-modified magnesium hydroxide flame retardant, and others were the same as those of Embodiment 1.

[0040] (3) Flame retardant properties of the intrinsic flame-retardant nylon 66 composite material: [0041] LOI=25.3%; THR=97.9 MJ/m.sup.2, PHRR=843.5 kW/m.sup.2, and TSP=8.0 m.sup.2.

Embodiment 4

[0042] (1) Preparation of a modified flame retardant: 3.9 g of aluminum hydroxide was dissolved in a round-bottom flask containing 100 mL distilled water, and ultrasonic treatment was performed for 30 min; 10.7 g of 2-carboxyethyl(phenyl)phosphinic acid was added into the flask, magnetic stirring was carried out at 100 C. for 5 h, the solvent was removed by rotary evaporation, and drying was carried out at 80 C. for 24 h to obtain a 2-carboxyethyl(phenyl)phosphinic acid-modified aluminum hydroxide flame retardant.

[0043] (2) Synthesis of a halogen-free low-smoke intrinsic flame-retardant nylon 66: The added flame retardant was the 2-carboxyethyl(phenyl)phosphinic acid-modified aluminum hydroxide flame retardant, and others were the same as those of Embodiment 1.

[0044] (3) Flame-retardant properties of the intrinsic flame-retardant nylon 66 composite material: [0045] LOI=24.7%; THR=98.5 MJ/m.sup.2, PHRR=860.8 kW/m.sup.2, and TSP=8.9 m.sup.2.

Embodiment 5

[0046] (1) Preparation of a modified flame retardant: 2.92 g of magnesium hydroxide was dissolved in a round-bottom flask containing 100 mL distilled water, and ultrasonic treatment was performed for 30 min; 7.95 g of phenylphosphonic acid was added into the flask, magnetic stirring was carried out at 80 C. for 5 h, and the solution was filtered and repeatedly washed with anhydrous ethanol, and dried at 80 C. for 24 h to obtain a phenylphosphonic acid-modified magnesium hydroxide flame retardant.

[0047] (2) Synthesis of a halogen-free low-smoke intrinsic flame-retardant nylon 66: The added flame retardant was the phenylphosphonic acid-modified magnesium hydroxide flame retardant, and others were the same as those of Embodiment 1.

[0048] (3) Flame-retardant properties of the intrinsic flame-retardant nylon 66 composite material: [0049] LOI=24.7%; THR=98.4 MJ/m.sup.2, PHRR=858.7 kW/m.sup.2, and TSP=8.8 m.sup.2.

Embodiment 6

[0050] (1) Preparation of a modified flame retardant: 0.29 g of magnesium hydroxide was dissolved in a round-bottom flask containing 100 mL distilled water, and ultrasonic treatment was performed for 30 min; 2.18 g of ethylenediamine tetra(methylene phosphonic acid) was added into the flask, magnetic stirring was carried out at 100 C. for 5 h, the solvent was removed by rotary evaporation, and drying was carried out at 80 C. for 24 h to obtain an ethylenediamine tetra(methylene phosphonic acid)-modified magnesium hydroxide flame retardant.

[0051] (2) Synthesis of a halogen-free low-smoke intrinsic flame-retardant nylon 66: The added flame retardant was the ethylenediamine tetra(methylene phosphonic acid)-modified magnesium hydroxide flame retardant, and others were the same as those of Embodiment 1.

[0052] (3) Flame-retardant properties of the intrinsic flame-retardant nylon 66 composite material: [0053] LOI=25.2%; THR=98.0 MJ/m.sup.2, PHRR=848.6 kW/m.sup.2, and TSP=8.2 m.sup.2.