Preparation process of high-toughness flame-retardant nylon material

Abstract

The invention relates to the technical field of nylon, and discloses a preparation process of a high-toughness flame-retardant nylon material, which comprises the following steps: adding water, potassium titanate whisker and a cationic polyamide flame retardant into a reaction kettle, heating, stirring, modifying, drying, removing water, mixing the mixture with nylon resin, extruding, and granulating to obtain the high-toughness flame-retardant nylon material. The surface of the potassium titanate whisker is modified with the cationic polyamide flame retardant, so that the compatibility between the potassium titanate whisker and nylon is improved, the interface bonding strength between the potassium titanate whisker and nylon resin is enhanced, the potassium titanate whisker has better toughening and reinforcing effects, and the impact strength and bending strength of the nylon material are remarkably improved. The cationic polyamide flame retardant contains a large amount of phosphamide flame-retardant groups to form a nitrogen-phosphorus flame-retardant system, so that the limit oxygen index and the flame-retardant property of the nylon material are obviously improved.

Description

Technical Field

[0001] The present invention relates to the technical field of nylon, and specifically to a preparation process of a high-toughness flame-retardant nylon material. Background Art

[0002] Nylon is a polyamide resin with excellent properties and is widely used in fields such as plastics, fibers, and concrete. Traditional nylon resins have problems such as low impact strength and poor toughness, and nylon resins are prone to burning and have poor flame retardancy, which limits the practical applications of nylon resins. It is of great significance to toughen and modify nylon while improving its flame retardant performance. Usually, rubber elastomers, nano-silica, potassium titanate whiskers and other toughening agents, as well as antimony trioxide, nitrogen-phosphorus series and other halogen-free flame retardants are added to nylon.

[0003] Potassium titanate whisker is a fibrous crystal material with high mechanical strength, heat resistance and other properties, and has extensive applications in the filling and modification of plastics such as nylon, polyurethane, and polyoxymethylene. Modifying the surface of potassium titanate whiskers to improve its compatibility with resin matrices such as nylon is a research difficulty. Commonly used modifiers include silane coupling agents, titanate coupling agents, epoxy resins, etc., but these modifiers cannot improve the flame retardant performance of resin materials such as nylon. Summary of the Invention

[0004] The technical problem solved by the present invention is: solving the problem of poor toughness and flame retardant performance of nylon materials.

[0005] The technical solution of the present invention is: a preparation process of a high-toughness flame-retardant nylon material:

[0006] (1) Add dichloromethane, triethylamine, N,N-dimethylethylenediamine, and phenyl dichlorophosphate to a reaction flask, stir and react at 30 - 45 °C for 6 - 10 h, rotary evaporate to remove dichloromethane, wash with water, dry the product, and recrystallize in dichloromethane to obtain phenyl bis(N,N-dimethylethylenediamine) phosphate. The reaction formula is:

[0007]

[0008] (2) Add ethanol, phenyl bis(N,N-dimethylethylenediamine) phosphate, and N,N'-bis(chloroacetyl) diamine monomer to a reaction flask equipped with a condenser reflux tube, heat and stir to react, rotary evaporate to remove ethanol, wash with petroleum ether, and dry to obtain a cationic polyamide flame retardant. The reaction formula is:

[0009]

[0010] (3) Add water, potassium titanate whiskers, and cationic polyamide flame retardant to the reaction kettle, heat and stir for modification, dry to remove water, then mix the mixture with nylon resin in a mixer, and then extrude in a twin-screw extruder and pelletize to obtain a high-toughness flame-retardant nylon material.

[0011] Preferably, the ratio of triethylamine, N,N-dimethylethylenediamine, and phenyl dichlorophosphate in (1) is (2 - 2.8) mol : (2 - 2.4) mol : 1 mol.

[0012] Preferably, the temperature during the stirring reaction in (2) is 75 - 85 °C, and the reaction time is 24 - 36 h.

[0013] Preferably, the ratio of bis(N,N-dimethylethylenediamine)phosphate phenyl ester to N,N'-bis(chloroacetyl)diamine monomer in (2) is (0.9 - 1.1) mol : 1 mol.

[0014] Preferably, the structural formula of the N,N'-bis(chloroacetyl)diamine monomer is a is any integer from 2 to 8.

[0015] Preferably, the ratio of the cationic polyamide flame retardant, potassium titanate whiskers, and nylon resin in (3) is (8 - 20) g : (30 - 60) g : 100 g.

[0016] Preferably, the temperature during the stirring modification in (3) is 65 - 80 °C, and the modification time is 6 - 12 h.

[0017] Preferably, the temperatures of the 1 - 6 zones of the twin-screw extruder in (3) are 210 - 270 °C, and the screw speed is 100 - 200 r / min.

[0018] The beneficial technical effect of the present invention is that bis(N,N-dimethylethylenediamine)phosphate phenyl ester and N,N'-bis(chloroacetyl)diamine monomer are subjected to a quaternization polymerization reaction to obtain a cationic polyamide flame retardant, which contains quaternary ammonium salt cations and can undergo an ion exchange reaction with K + ions, thereby modifying the cationic polyamide flame retardant on the surface of potassium titanate whiskers. The molecular main chain of the polyamide flame retardant contains a large number of amide bonds, which is similar to the structure of the polyamide molecular chain of nylon resin, and the compatibility between the two is very good, thus improving the compatibility between potassium titanate whiskers and nylon, enhancing the interfacial bonding strength between potassium titanate whiskers and nylon resin, enabling potassium titanate whiskers to play a better toughening and strengthening role, and significantly improving the impact strength and flexural strength of the nylon material.

[0019] The cationic polyamide flame retardant of the present invention contains a large number of phosphoramide flame retardant groups to form a nitrogen-phosphorus flame retardant system. When burned at high temperature, it is pyrolyzed to form phosphoric acid substances, which promote the dehydration of the nylon matrix into carbon and generate nitrogen-containing non-combustible gas at the same time to dilute oxygen and inhibit combustion, thereby achieving a good flame retardant effect and significantly improving the limiting oxygen index and flame retardant performance. DETAILED DESCRIPTION

[0020] The technical solution of the present invention is further described in detail below through specific embodiments. It should be understood that the implementation of the present invention is not limited to the following embodiments, and any form of modification and / or change made to the present invention will fall within the protection scope of the present invention.

[0021] The nylon resin is 1030U2, purchased from Shanghai Hengpeng Plastics Co., Ltd. The potassium titanate whisker has a specification of 5-10 um, purchased from Hubei Yamade Biopharmaceutical Co., Ltd.

[0022] According to the journal "Inorganic Chemistry" 2014, 53, 13, 6698-6707, the literature "BispidineDioxotetraaza Macrocycles: A New Class ofBispidines for 64 The N,N'-bis(chloroacetyl)ethylenediamine monomer and N,N'-bis(chloroacetyl)propylenediamine monomer were prepared by the method of "Cu PET Imaging".

[0023] In an ice-water bath, 22.5 mL of dichloromethane, 29.95 mmol of ethylenediamine, 74.88 mmol of potassium carbonate, and 17.5 mL of water were added to the reaction bottle, and 59.90 mmol of chloroacetyl chloride was added dropwise, stirred for 1 hour, and then stirred and reacted at 25°C for 12 hours. The dichloromethane was removed by rotary evaporation, filtered and washed with water, and the product was dried and recrystallized in acetonitrile to obtain N,N'-bis(chloroacetyl)ethylenediamine monomer with the structural formula

[0024]

[0025] In an ice water bath, 18 mL of dichloromethane, 29.96 mmol of 1,3-propylenediamine, 59.9 mmol of potassium carbonate, and 14 mL of water were added to the reaction bottle, and 47.92 mmol of chloroacetyl chloride was added dropwise, stirred for 1 hour, and then stirred and reacted at 25°C for 12 hours. The dichloromethane was removed by rotary evaporation, filtered and washed with water, and the product was dried and recrystallized in acetonitrile to obtain N,N'-bis(chloroacetyl)propylenediamine monomer with the structural formula

[0026]

[0027] Embodiment 1:

[0028] (1) Add 100 mL of dichloromethane, 80 mmol of triethylamine, 80 mmol of N,N-dimethylethylenediamine, and 40 mol of phenyl dichlorophosphate to the reaction flask. Stir and react at 30 °C for 10 h. Remove dichloromethane by rotary evaporation. After washing with water, dry the product and recrystallize it from dichloromethane to obtain phenyl bis(N,N-dimethylethylenediamine) phosphate.

[0029] (2) Add 600 mL of ethanol, 100 mmol of phenyl bis(N,N-dimethylethylenediamine) phosphate, and 100 mmol of N,N'-bis(chloroacetyl)ethylenediamine monomer to the reaction flask equipped with a condenser. Heat to 85 °C and stir and react for 24 h. Remove ethanol by rotary evaporation, wash with petroleum ether, and dry to obtain a cationic polyamide flame retardant.

[0030] (3) Add 20 L of water, 300 g of potassium titanate whiskers, and 80 g of the cationic polyamide flame retardant to the reaction kettle. Heat to 80 °C and stir and modify for 6 h. Dry to remove water. Then mix the mixture with 1 kg of nylon resin in a mixer and then extrude it in a twin-screw extruder. The temperatures of zones 1-6 are 210 °C, 240 °C, 255 °C, 270 °C, 270 °C, and 260 °C, and the screw speed is 100 r / min for pelletizing to obtain a high-toughness flame-retardant nylon material.

[0031] Example 2:

[0032] (1) Add 150 mL of dichloromethane, 112 mmol of triethylamine, 96 mmol of N,N-dimethylethylenediamine, and 40 mol of phenyl dichlorophosphate to the reaction flask. Stir and react at 40 °C for 10 h. Remove dichloromethane by rotary evaporation. After washing with water, dry the product and recrystallize it from dichloromethane to obtain phenyl bis(N,N-dimethylethylenediamine) phosphate.

[0033] (2) Add 500 mL of ethanol, 90 mmol of phenyl bis(N,N-dimethylethylenediamine) phosphate, and 100 mmol of N,N'-bis(chloroacetyl)ethylenediamine monomer to the reaction flask equipped with a condenser. Heat to 80 °C and stir and react for 36 h. Remove ethanol by rotary evaporation, wash with petroleum ether, and dry to obtain a cationic polyamide flame retardant.

[0034] (3) Add 40 L of water, 450 g of potassium titanate whiskers, and 140 g of the cationic polyamide flame retardant to the reaction kettle. Heat to 65 °C and stir and modify for 12 h. Dry to remove water. Then mix the mixture with 1 kg of nylon resin in a mixer and then extrude it in a twin-screw extruder. The temperatures of zones 1-6 are 210 °C, 240 °C, 255 °C, 270 °C, 270 °C, and 260 °C, and the screw speed is 200 r / min for pelletizing to obtain a high-toughness flame-retardant nylon material.

[0035] Example 3:

[0036] (1) Add 100 mL of dichloromethane, 92 mmol of triethylamine, 84 mmol of N,N-dimethylethylenediamine, and 40 mol of phenyl dichlorophosphate to a reaction flask. Stir and react at 45 °C for 6 h. Rotate and evaporate to remove dichloromethane. After washing with water, dry the product and recrystallize it from dichloromethane to obtain phenyl phosphate bis(N,N-dimethylethylenediamine).

[0037] (2) Add 600 mL of ethanol, 110 mmol of phenyl phosphate bis(N,N-dimethylethylenediamine), and 100 mmol of N,N'-bis(chloroacetyl)propanediamine monomer to a reaction flask equipped with a condenser reflux tube. Heat to 75 °C and stir and react for 36 h. Rotate and evaporate to remove ethanol. Wash with petroleum ether, dry, and obtain a cationic polyamide flame retardant.

[0038] (3) Add 65 L of water, 600 g of potassium titanate whiskers, and 200 g of cationic polyamide flame retardant to a reaction kettle. Heat to 70 °C and stir and modify for 12 h. Dry to remove water. Then mix the mixture with 1 kg of nylon resin in a mixer, and then extrude it in a twin-screw extruder. The temperatures of zones 1-6 are 210 °C, 240 °C, 255 °C, 270 °C, 270 °C, and 260 °C, and the screw speed is 200 r / min for pelletizing to obtain a high-toughness flame-retardant nylon material.

[0039] Comparative Example 1:

[0040] (1) Extrude 1 kg of nylon resin in a twin-screw extruder. The temperatures of zones 1-6 are 210 °C, 240 °C, 255 °C, 270 °C, 270 °C, and 260 °C, and the screw speed is 100 r / min for pelletizing to obtain a nylon material.

[0041] Comparative Example 2:

[0042] (1) Mix 80 g of cationic polyamide flame retardant and 1 kg of nylon resin in a mixer, and then extrude it in a twin-screw extruder. The temperatures of zones 1-6 are 210 °C, 240 °C, 255 °C, 270 °C, 270 °C, and 260 °C, and the screw speed is 100 r / min for pelletizing to obtain a nylon material.

[0043] Comparative Example 3:

[0044] (1) Mix 300 g of potassium titanate whiskers and 1 kg of nylon resin in a mixer, and then extrude it in a twin-screw extruder. The temperatures of zones 1-6 are 210 °C, 240 °C, 255 °C, 270 °C, 270 °C, and 260 °C, and the screw speed is 100 r / min for pelletizing to obtain a nylon material.

[0045] Comparative Example 4

[0046] (1) Add 600 mL of ethanol, 100 mmol of phenyl phosphate bis(N,N-dimethylethylenediamine), and 100 mmol of 1,4-dichlorobutane to a reaction flask equipped with a condenser reflux tube. Heat to 85 °C and stir the reaction for 24 h. Rotate and evaporate to remove ethanol, wash with petroleum ether, and dry to obtain a cationic flame retardant.

[0047] (2) Add 25 L of water, 300 g of potassium titanate whiskers, and 80 g of the cationic flame retardant to a reaction kettle. Heat to 80 °C and stir for modification for 6 h. Dry to remove water. Then mix the mixture with 1 kg of nylon resin in a mixer, and then extrude in a twin-screw extruder. The temperatures of zones 1-6 are 210 °C, 240 °C, 255 °C, 270 °C, 270 °C, and 260 °C, and the screw speed is 100 r / min for pelletizing to obtain a nylon material.

[0048] Comparative Example 5:

[0049] (1) Prepare bis(hydroxyacetyl)ethylenediamine according to the method in the journal "Organic Preparations and Procedures International", Volume 32, No. 1, 2000, p. 84-88, and the literature "Synthesis and characterization of N-alkylhydroxyacetamides". Add 1 g of ethylenediamine and 2.53 g of glycolic acid to a reaction flask, stir the reaction at 90 °C for 2 h, wash with acetone, and dry to obtain bis(hydroxyacetyl)ethylenediamine, and the structural formula is

[0050] (2) Add 100 mL of tetrahydrofuran, 100 mmol of N,N'-bis(hydroxyacetyl)ethylenediamine, and 200 mmol of triethylamine to a reaction flask equipped with a condenser reflux tube. Add 100 mmol of phenyl phosphate dichloride in an ice-water bath, stir the reaction at 25 °C for 2 h, and then stir the reaction at 40 °C for 6 h. After filtration, rotate and evaporate the filtrate, wash with petroleum ether, and dry to obtain a polyamide flame retardant. The structural formula is as follows:

[0051]

[0052] (3) Add 25 L of water, 300 g of potassium titanate whiskers, and 80 g of the polyamide flame retardant to a reaction kettle. Heat to 80 °C and stir for modification for 6 h. Dry to remove water. Then mix the mixture with 1 kg of nylon resin in a mixer, and then extrude in a twin-screw extruder. The temperatures of zones 1-6 are 210 °C, 240 °C, 255 °C, 270 °C, 270 °C, and 260 °C, and the screw speed is 100 r / min for pelletizing to obtain a nylon material.

[0053] The nylon material is injection molded, and the impact strength is tested according to the standard of GB / T 1043.1-2008. The flexural strength is tested according to the standard of GB / T 9341-2000. The oxygen index is tested according to the standard of GB / T 2406.1-2008.

[0054] Table 1 Properties of Nylon Materials

[0055]

[0056] After testing, the nylon material in Comparative Example 1 has low impact strength and flexural strength, poor toughness, and low limiting oxygen index, resulting in poor flame retardancy.

[0057] In Comparative Example 2, a cationic polyamide flame retardant was added. Its molecular main chain contains a large number of amide bonds, which is similar to the molecular chain structure of the polyamide in nylon resin, and the compatibility between the two is very good. Adding the cationic polyamide flame retardant has little effect on the mechanical properties of the nylon material, and the impact strength and flexural strength are not affected. Moreover, the flame retardant contains a large number of phosphoamide flame retardant groups It forms a nitrogen-phosphorus flame retardant system. When burning at high temperature, it pyrolyzes to form phosphoric acid substances, which promote the dehydration and carbonization of the nylon matrix. At the same time, nitrogen-containing non-combustible gases are generated, diluting oxygen and inhibiting combustion, achieving a good flame retardant effect and significantly improving the limiting oxygen index and flame retardant performance.

[0058] In Comparative Example 3, potassium titanate whiskers were added, which have a certain toughening effect on the nylon material. However, the compatibility between potassium titanate whiskers and nylon resin is poor, and the increase in the impact strength and flexural strength of the material is relatively low.

[0059] In Examples 1-3, the surface of potassium titanate whiskers was modified with a cationic polyamide flame retardant. The quaternary ammonium salt cation of the flame retardant undergoes an ion exchange reaction with the K + ions in potassium titanate whiskers, thereby modifying the cationic polyamide flame retardant on the surface of potassium titanate whiskers. Since the polyamide flame retardant has good compatibility with nylon resin, the compatibility between potassium titanate whiskers and nylon is improved, and the interfacial bonding strength between the two is enhanced, enabling the potassium titanate whiskers to play a better toughening and strengthening role, and significantly improving the impact strength and flexural strength of the nylon material.

[0060] In Comparative Example 4, a quaternization polymerization reaction was carried out using bis(N,N-dimethylethylenediamine) phenyl phosphate and 1,4-dichlorobutane. The resulting cationic flame retardant can undergo an ion exchange reaction with potassium titanate whiskers and be modified on its surface. However, the cationic flame retardant does not contain a large number of amide bonds, and its compatibility with nylon resin is poor, making it difficult to effectively improve the compatibility and interfacial bonding strength between potassium titanate whiskers and nylon resin, resulting in a lower toughening and strengthening effect of potassium titanate whiskers, and the impact strength and flexural strength are lower than those in Example 1.

[0061] Comparative Example 5 uses N,N'-bis(hydroxyacetyl)ethylenediamine and phenyl phosphorodichloridate for phosphorylation reaction to obtain a polyamide flame retardant, which does not contain quaternary ammonium salt cations and cannot undergo ion exchange with potassium titanate whiskers, and thus cannot achieve surface modification of potassium titanate whiskers by water, and does not improve the compatibility and interfacial bonding strength between potassium titanate whiskers and nylon resin, resulting in a relatively low toughening and strengthening effect of potassium titanate whiskers, and the impact strength and flexural strength are lower than those of Example 1.

[0062] The description of the above embodiments is only used to help understand the method and its core idea of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A preparation process of a high-toughness flame-retardant nylon material, characterized in that, The preparation process includes the following steps: (1) Add ethanol, phenyl phosphate bis(N,N-dimethylethylenediamine), and N,N'-bis(chloroacetyl) diamine monomer into a reaction flask, heat and stir for reaction, rotary evaporate, wash, and dry to obtain a cationic polyamide flame retardant; The structural formula of the N,N'-bis(chloroacetyl) diamine monomer is a is any integer from 2 to 8; (2) Add water, potassium titanate whiskers, and the cationic polyamide flame retardant into a reaction kettle, heat and stir for modification, dry to remove water, then mix the mixture with nylon resin in a mixer, and then extrude in a twin-screw extruder, pelletize to obtain a high-toughness flame-retardant nylon material.

2. The preparation process of the high-toughness flame-retardant nylon material according to claim 1, characterized in that, In the step (1), the temperature during the stirring reaction is 75-85 °C, and the reaction time is 24-36 h.

3. The preparation process of the high-toughness flame-retardant nylon material according to claim 1, characterized in that, In the step (1), the ratio of phenyl phosphate bis(N,N-dimethylethylenediamine) to N,N'-bis(chloroacetyl) diamine monomer is (0.9-1.1) mol:1 mol.

4. The preparation process of the high-toughness flame-retardant nylon material according to claim 3, characterized in that, The preparation method of phenyl phosphate bis(N,N-dimethylethylenediamine) is as follows: Add dichloromethane, triethylamine, N,N-dimethylethylenediamine, and phenyl dichlorophosphate into a reaction flask, stir and react at 30-45 °C for 6-10 h, rotary evaporate, wash the product and then dry it, and recrystallize to obtain phenyl phosphate bis(N,N-dimethylethylenediamine).

5. The preparation process of the high-toughness flame-retardant nylon material according to claim 4, characterized in that, The ratio of triethylamine, N,N-dimethylethylenediamine, and phenyl dichlorophosphate is (2-2.8) mol:(2-2.4) mol:1 mol.

6. The preparation process of the high-toughness flame-retardant nylon material according to claim 1, characterized in that, In the step (2), the ratio of the cationic polyamide flame retardant, potassium titanate whiskers, and nylon resin is (8-20) g:(30-60) g:100 g.

7. The preparation process of the high-toughness flame-retardant nylon material according to claim 1, characterized in that, In the step (2), the temperature during the stirring modification is 65-80 °C, and the modification time is 6-12 h.

8. The preparation process of the high-toughness flame-retardant nylon material according to claim 1, characterized in that, In the step (2), the temperatures of the 1-6 zones of the twin-screw extruder are 210-270 °C, and the screw speed is 100-200 r / min.

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