Halogen-free flame-retardant nylon material and method for preparing the same

Abstract

The application relates to the technical field of nylon, and discloses a halogen-free flame-retardant nylon material and a preparation method thereof. The halogen-free flame-retardant nylon material comprises 70-85 parts by weight of nylon resin and 15-30 parts by weight of modified polystyrene. The epoxy groups of the modified polystyrene can react with the terminal amino groups of the nylon, thereby improving the interface bonding force of the nylon resin and the polystyrene molecular chains, and making the material have higher tensile strength and mechanical properties. The modified polystyrene contains a large number of phosphate flame-retardant groups, has a condensation flame-retardant effect, produces phosphoric acid substances during combustion, promotes the dehydration of the high-carbon-content polystyrene into carbon, can insulate oxygen, prevents heat conduction, has a good flame-retardant effect, improves the limiting oxygen index of the nylon material, and makes the UL-94 grade reach the V-1 to V-0 grade.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of nylon, in particular to a halogen-free flame-retardant nylon material and a preparation method thereof. BACKGROUND

[0002] Nylon is a kind of polyamide high polymer material, which has excellent corrosion resistance, good wear resistance and strong temperature resistance, and is widely used. However, the limiting oxygen index of nylon material is low, which is easy to burn, and the practical application is greatly limited. Polystyrene has good transparency, insulation, low temperature resistance and chemical stability. By introducing phosphoric acid ester, bromine and other flame-retardant groups into the polystyrene molecular chain, a polymer flame retardant with excellent performance can be prepared.

[0003] The plastic alloy material prepared by blending nylon resin and polystyrene has better mechanical strength and other properties. The patent with publication number CN105802210B discloses a polystyrene organic rigid particle modified nylon filament for 3D printing and a preparation method thereof. The strength and other properties of nylon are improved by using polystyrene organic rigid particles, but the problem of poor flame retardancy of nylon material is not solved. SUMMARY

[0004] In view of the shortcomings of the prior art, the present application provides a halogen-free flame-retardant nylon material and a preparation method thereof, which solves the problem of poor compatibility of nylon and polystyrene, and improves the flame retardancy of nylon material.

[0005] In order to solve the above technical problems, the technical scheme adopted by the present application is as follows: a halogen-free flame-retardant nylon material and a preparation method thereof, the halogen-free flame-retardant nylon material comprises 70-85 parts by weight of nylon resin and 15-30 parts by weight of modified polystyrene; the preparation method of the halogen-free flame-retardant nylon material is as follows:

[0006] (1) styrene, phosphoric acid ester styrene monomer are added to the solvent, after stirring, initiator is added in nitrogen atmosphere, after polymerization reaction, the solution is poured into ethanol, the precipitate is washed with ethanol after filtration, and dried to obtain modified polystyrene.

[0007] (2) the nylon resin and the modified polystyrene are mixed, extruded in a double screw extruder, and granulated to obtain the halogen-free flame-retardant nylon material.

[0008] Further, the temperature of polymerization reaction in (1) is 60-75℃, and the reaction time is 5-8h.

[0009] Further, the solvent in (1) includes toluene, tetrahydrofuran or N,N-dimethylformamide.

[0010] Further, the molar ratio of styrene, phosphoric acid ester styrene monomer and initiator in (1) is (60-80):(20-40):(0.32-0.46).

[0011] Further, the initiator includes azobisisobutyronitrile.

[0012] Further, the temperature of the 1-5 zones of the twin-screw extruder in (2) is 180-240 DEG C.

[0013] Further, the preparation method of the phosphate styrene monomer is as follows: under ice bath and nitrogen atmosphere, phosphate benzene dichloride, triethylamine are added into tetrahydrofuran, a tetrahydrofuran solution containing (4-vinylphenyl)methanol is added dropwise under stirring, and then a tetrahydrofuran solution containing glycidol is added dropwise, and the reaction is carried out at 15-25 DEG C for 5-8 h, then the filtrate is concentrated under reduced pressure, the crude product is washed with petroleum ether, and then purified by recrystallization in chloroform to obtain the phosphate styrene monomer.

[0014] Further, the molar ratio of phosphate benzene dichloride, triethylamine, (4-vinylphenyl)methanol and glycidol is 1: (2-2.2): 1: (1-1.2).

[0015] (Three) beneficial technical effects: the phosphate styrene monomer containing phosphate and epoxy groups is copolymerized with styrene to obtain modified polystyrene, and then the modified polystyrene is blended and extruded with nylon resin, the modified polystyrene contains epoxy groups, and in the process of high-temperature melting and extrusion, the epoxy groups can react with the terminal amino groups of the nylon, thereby improving the interfacial bonding force of the molecular chains of the nylon resin and the polystyrene, and the compatibility of the two is better, and the tensile strength and mechanical properties are higher.

[0016] The modified polystyrene contains a large amount of phosphate flame-retardant groups, has a condensation flame-retardant effect, produces phosphoric acid substances during combustion, promotes the dehydration of high-carbon-content polystyrene into carbon, can isolate oxygen and prevent heat conduction, has a good flame-retardant effect, improves the limiting oxygen index of the nylon material, and the UL-94 grade reaches V-1 to V-0 grade. DETAILED DESCRIPTION

[0017] The content of the present application can be more easily understood by referring to the following detailed description of the preferred embodiments of the present application and the examples included. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. In case of conflict, the definitions in the specification prevail.

[0018] The following nylon resin model is PA6 M2800, which is from Shanghai and Hongcheng Plastic Co., Ltd.

[0019] Example 1:

[0020] (1) Under an ice bath, under a nitrogen atmosphere, 0.3 mol of phenyl phosphonic dichloride, 0.6 mol of triethylamine were added to 350 mL of tetrahydrofuran, and 120 mL of a tetrahydrofuran solution containing 0.3 mol of (4-vinylphenyl)methanol was added dropwise while stirring, and the reaction was performed for 6 h, and then 150 mL of a tetrahydrofuran solution containing 0.3 mol of glycidol was added dropwise, and the reaction was performed for 8 h at 15°C, and after filtration, the filtrate was concentrated under reduced pressure, and the crude product was washed with petroleum ether, and then purified by recrystallization in chloroform to obtain a phosphonate styrene monomer. The preparation reaction formula is:

[0021]

[0022] (2) 0.8 mol of styrene, 0.2 mol of the phosphonate styrene monomer were added to 700 mL of toluene, and after stirring, 4 mmol of an initiator, azobisisobutyronitrile, was added under a nitrogen atmosphere, and heated to 75°C, and the reaction was performed for 5 h, and the solution was poured into ethanol, and after filtration, the precipitate was washed with ethanol, and dried to obtain a modified polystyrene.

[0023] (3) 8.5 kg of nylon resin, 1.5 kg of the modified polystyrene were mixed, and extruded in a twin-screw extruder, and the temperature of 1-5 zones was 180°C, 215°C, 230°C, 240°C, 235°C, and pelletized to obtain a halogen-free flame-retardant nylon material.

[0024] Example 2:

[0025] (1) Under an ice bath, under a nitrogen atmosphere, 0.3 mol of phenyl phosphonic dichloride, 0.6 mol of triethylamine were added to 350 mL of tetrahydrofuran, and 120 mL of a tetrahydrofuran solution containing 0.3 mol of (4-vinylphenyl)methanol was added dropwise while stirring, and the reaction was performed for 6 h, and then 150 mL of a tetrahydrofuran solution containing 0.3 mol of glycidol was added dropwise, and the reaction was performed for 8 h at 15°C, and after filtration, the filtrate was concentrated under reduced pressure, and the crude product was washed with petroleum ether, and then purified by recrystallization in chloroform to obtain a phosphonate styrene monomer. The preparation reaction formula is:

[0026] (2) 0.8 mol of styrene, 0.2 mol of the phosphonate styrene monomer were added to 700 mL of toluene, and after stirring, 4 mmol of an initiator, azobisisobutyronitrile, was added under a nitrogen atmosphere, and heated to 75°C, and the reaction was performed for 5 h, and the solution was poured into ethanol, and after filtration, the precipitate was washed with ethanol, and dried to obtain a modified polystyrene.

[0027] (3) 8.5 kg of nylon resin, 1.5 kg of the modified polystyrene were mixed, and extruded in a twin-screw extruder, and the temperature of 1-5 zones was 180°C, 215°C, 230°C, 240°C, 235°C, and pelletized to obtain a halogen-free flame-retardant nylon material.

[0028] Example 3:

[0029] (1) To 900 mL of tetrahydrofuran was added 0.6 mol of styrene, 0.4 mol of phosphonate styrene monomer (prepared from Example 1), after stirring, 3.2 mmol of initiator azobisisobutyronitrile was added under nitrogen atmosphere, heated to 70°C, reacted for 8 h, the solution was poured into ethanol, after filtration, the precipitate was washed with ethanol, dried, to obtain modified polystyrene.

[0030] (2) 7.5 kg of nylon resin, 2.5 kg of modified polystyrene were mixed, extruded in a twin-screw extruder, the temperature of 1-5 zones was 180°C, 215°C, 230°C, 240°C, 235°C, pelletized, to obtain halogen-free flame-retardant nylon material.

[0031] Example 4:

[0032] (1) To 700 mL of N,N-dimethylformamide was added 0.73 mol of styrene, 0.27 mol of phosphonate styrene monomer (prepared from Example 1), after stirring, 4.2 mmol of initiator azobisisobutyronitrile was added under nitrogen atmosphere, heated to 60°C, reacted for 8 h, the solution was poured into ethanol, after filtration, the precipitate was washed with ethanol, dried, to obtain modified polystyrene.

[0033] (2) 7 kg of nylon resin, 3 kg of modified polystyrene were mixed, extruded in a twin-screw extruder, the temperature of 1-5 zones was 180°C, 215°C, 230°C, 240°C, 235°C, pelletized, to obtain halogen-free flame-retardant nylon material.

[0034] Comparative Example 1:

[0035] (2) To 700 mL of toluene was added 1 mol of styrene, after stirring, 4 mmol of initiator azobisisobutyronitrile was added under nitrogen atmosphere, heated to 75°C, reacted for 5 h, the solution was poured into ethanol, after filtration, the precipitate was washed with ethanol, dried, to obtain polystyrene.

[0036] (3) 8.5 kg of nylon resin, 1.5 kg of polystyrene were mixed, extruded in a twin-screw extruder, the temperature of 1-5 zones was 180°C, 215°C, 230°C, 240°C, 235°C, pelletized, to obtain nylon material.

[0037] Comparative Example 2:

[0038] (1) To 700 mL of toluene was added 0.8 mol of styrene, 0.2 mol of glycidyl methacrylate, after stirring, 4 mmol of initiator azobisisobutyronitrile was added under nitrogen atmosphere, heated to 75°C, reacted for 5 h, the solution was poured into ethanol, after filtration, the precipitate was washed with ethanol, dried, to obtain modified polystyrene.

[0039] (2) 8.5 kg of the nylon resin and 1.5 kg of the modified polystyrene were mixed and extruded in a twin-screw extruder, with the temperature of zones 1-5 being 180°C, 215°C, 230°C, 240°C, and 235°C, and the mixture was pelletized to obtain the nylon material.

[0040] Comparative Example 3

[0041] (1) 0.3 mol of phenylphosphonic dichloride and 0.6 mol of triethylamine were added to 350 mL of tetrahydrofuran under stirring and in an ice bath under a nitrogen atmosphere, and 120 mL of a tetrahydrofuran solution containing 0.3 mol of hydroxyethyl acrylate was added dropwise, and the reaction was allowed to proceed for 6 h. Then, 150 mL of a tetrahydrofuran solution containing 0.3 mol of glycidol was added dropwise, and the reaction was allowed to proceed for 8 h at 15°C. After filtration, the filtrate was concentrated under reduced pressure, and the crude product was washed with petroleum ether and then recrystallized in chloroform to obtain a phosphonate acrylate monomer. The structural formula is

[0042] (2) 0.8 mol of styrene and 0.2 mol of the phosphonate acrylate monomer were added to 700 mL of toluene, and 4 mmol of an initiator, azobisisobutyronitrile, was added after stirring under a nitrogen atmosphere. The solution was heated to 75°C, and the reaction was allowed to proceed for 5 h. The solution was poured into ethanol, and the precipitate was washed with ethanol after filtration and dried to obtain the modified polystyrene.

[0043] (3) 8.5 kg of the nylon resin and 1.5 kg of the modified polystyrene were mixed and extruded in a twin-screw extruder, with the temperature of zones 1-5 being 180°C, 215°C, 230°C, 240°C, and 235°C, and the mixture was pelletized to obtain the halogen-free flame-retardant nylon material.

[0044] The nylon material was injected into a sample bar by an injection molding machine, and the combustion performance of the sample bar was tested according to the GB / T 2406.1-2008 standard and the UL-94 method. The tensile strength was tested according to the GB / T 1040.1-2018 standard.

[0045] Table 1 Properties of the nylon material

[0046] Limiting oxygen index (%) UL-94 rating Tensile strength (MPa) Example 1 26.7 V-1 44.2 Example 2 27.2 V-1 45.9 Example 3 28.5 V-0 42.0 Example 4 27.9 V-0 38.1 Comparative Example 1 21.6 - 38.7 Comparative Example 2 20.8 - 41.3 Comparative Example 3 25.4 V-2 40.6

[0047] The modified polystyrene added in the nylon material of embodiments 1-4 contains epoxy groups, which can react with the terminal amino groups of the nylon during high-temperature melt extrusion, thereby improving the interfacial bonding force of the nylon resin and the polystyrene molecular chain, better compatibility, higher tensile strength and mechanical properties, and the modified polystyrene contains a large number of phosphate flame-retardant groups, has a condensation flame-retardant effect, produces phosphoric acid substances during combustion, promotes the dehydration of high-carbon polystyrene into carbon, can isolate oxygen and prevent heat conduction, has good flame-retardant effect, improves the limiting oxygen index of the nylon material, and the UL-94 level reaches V-1 to V-0 level.

[0048] Compared with example 1, the comparative example 1 blends the nylon resin and polystyrene, which has poor compatibility, resulting in lower tensile strength of the material, lower limiting oxygen index, and UL-94 experiment failure, no grade, poor flame-retardant performance.

[0049] The comparative example 2 copolymerizes styrene and glycidyl methacrylate to obtain modified polystyrene containing epoxy groups, which can react with the terminal amino groups of the nylon, thereby improving the interfacial bonding force of the nylon resin and the polystyrene molecular chain, and being beneficial to improve the tensile strength of the nylon material, but the glycidyl methacrylate copolymerization does not contain styrene structure, and the introduction of polyacrylate molecular chain in the polystyrene molecular chain after copolymerization with styrene affects the mechanical properties of the polystyrene, and after blending with the nylon, the tensile strength of the material is lower than that of example 1.

[0050] The comparative example 3 copolymerizes the phosphate ester acrylate monomer and styrene to obtain modified polystyrene containing polyacrylate molecular chain, which affects the mechanical properties of the polystyrene, and after blending with the nylon, the tensile strength of the material is lower than that of example 1. And the carbonization of acrylate is lower than that of benzene ring structure, resulting in poor flame-retardant performance of the nylon material of comparative example 3, lower limiting oxygen index than example 1, and UL-94 only V-2 level.

[0051] The above examples are only illustrative and are used to explain some features of the features of the present application. The appended claims are intended to require as broad a scope as can be conceived, and the examples presented herein are only illustrative of selected embodiments according to all possible combinations of embodiments.

Claims

1. A halogen-free flame-retardant nylon material, characterized by, The halogen-free flame-retardant nylon material comprises 70-85 parts by weight of nylon resin and 15-30 parts by weight of modified polystyrene. The preparation method of the modified polystyrene comprises: adding styrene and phosphate styrene monomer into a solvent, stirring, then adding an initiator in a nitrogen atmosphere, pouring the solution into ethanol after polymerization, washing the precipitate after filtration, drying, and obtaining the modified polystyrene. The structural formula of the phosphate styrene monomer is 2. The halogen-free flame retardant nylon material of claim 1, wherein, The temperature of the polymerization reaction is 60-75 DEG C, and the reaction time is 5-8 h.

3. The halogen-free flame retardant nylon material of claim 1, wherein, The solvent comprises toluene, tetrahydrofuran or N, N-dimethylformamide.

4. The halogen-free flame retardant nylon material of claim 1, wherein, The molar ratio of the styrene, phosphate styrene monomer and initiator is (60-80):(20-40):(0.32-0.46).

5. The halogen-free flame retardant nylon material of claim 4, wherein, The initiator comprises azobisisobutyronitrile.

6. The halogen-free flame retardant nylon material of claim 4, wherein, The preparation method of the phosphate styrene monomer is: under ice bath and in a nitrogen atmosphere, adding phenyl phosphate dichloride and triethylamine into tetrahydrofuran, stirring, dropwise adding a tetrahydrofuran solution containing (4-vinylphenyl)methanol, reacting for 4-6 h, then dropwise adding a tetrahydrofuran solution containing glycidol, reacting for 5-8 h at 15-25 DEG C, filtering, then reducing pressure to concentrate the filtrate, washing the crude product, then recrystallizing and purifying to obtain the phosphate styrene monomer.

7. The halogen-free flame retardant nylon material of claim 6, wherein, The molar ratio of the phenyl phosphate dichloride, triethylamine, (4-vinylphenyl)methanol and glycidol is 1:(2-2.2):1:(1-1.2).

8. A process for the preparation of a halogen-free flame-retardant nylon material as claimed in any one of claims 1 to 7, characterized in that, The preparation method comprises: mixing the nylon resin and the modified polystyrene, extruding in a double-screw extruder, and granulating to obtain the halogen-free flame-retardant nylon material.

9. The method of making a halogen-free flame retardant nylon material of claim 8, wherein, The temperature of the 1-5 zones of the double-screw extruder is 180-240 DEG C.

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