Flame-retardant nylon composite material and method for preparing the same

Abstract

The application relates to the technical field of materials, and discloses a flame-retardant nylon composite material and a preparation method thereof.The composite material is prepared by mixing and extruding nylon 6 resin as a base material and glass fibers, macromolecular multi-component flame retardants and the like as auxiliary materials.The macromolecular multi-component flame retardant structure contains a large number of ester groups, can have good compatibility with the nylon 6, can effectively avoid the migration and precipitation of the macromolecular multi-component flame retardant, and on the other hand, the phosphorus element and the sulfur element contained in the structure can serve as an acid source, the nitrogen element can serve as a gas source, and the two can form a synergistic flame-retardant effect, can quickly form an expanded carbon layer during combustion, highly insulate oxygen and heat from the outside, prevent the combustion from continuing to the inside, and greatly improve the flame-retardant performance of the composite material.

Description

Technical Field

[0001] This invention relates to the field of materials technology, specifically to a flame-retardant nylon composite material and its preparation method. Background Technology

[0002] Nylon composite materials are high-performance materials made by compounding nylon resin with other reinforcing materials (such as glass fiber, carbon fiber, etc.) and additives (such as flame retardants, plasticizers, etc.) through specific processes. Among them, nylon 6, as one of the most common types of nylon, occupies an important position in the field of composite materials due to its excellent strength, wear resistance and good processing performance. It is currently widely used in textiles, carpets, ropes, industrial belts, as well as in the automotive, electronics and electrical industries and many other fields.

[0003] Despite its numerous advantages, nylon 6 has a low flame retardant rating when untreated, achieving only UL94 V-2 in vertical burning conditions. This means that nylon 6 will burn rapidly upon contact with an open flame and may drip, causing the flame to spread. Therefore, flame retardant modification is particularly necessary for nylon 6 composites that need to operate under special conditions such as high temperatures and flammability.

[0004] Flame retardant modification of nylon 6 composites is mainly achieved by adding flame retardants, generally inorganic, phosphorus-based, and halogen-based flame retardants. Inorganic flame retardants, however, have poor modification effects, requiring large quantities to achieve noticeable results, which can impact the material's mechanical properties. Organic flame retardants include halogen-based and phosphorus-based flame retardants. Halogen-based flame retardants have significant drawbacks, easily producing large amounts of toxic fumes during combustion, and are therefore gradually becoming unsuitable. Small-molecule phosphorus-based flame retardants have compatibility issues with the matrix, are prone to precipitation, and struggle to produce sustained modification effects. Furthermore, single phosphorus-based flame retardants also exhibit poor modification effects. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] To address the shortcomings of existing technologies, this invention provides a flame-retardant nylon composite material and its preparation method.

[0007] (II) Technical Solution

[0008] A method for preparing a flame-retardant nylon composite material, wherein the composite material comprises the following raw materials measured in parts by weight:

[0009]

[0010] The preparation method includes the following steps:

[0011] Step 1: Weigh and prepare all the raw materials according to their weight proportions;

[0012] The second step involves adding all raw materials to a high-speed mixer, raising the temperature to 100-120℃, and mechanically mixing them at a stirring rate of 1000-1500 r / min for 30-60 minutes. The mixture is then transferred to a twin-screw extruder, with the extruder temperatures controlled as follows: conveying section 190-200℃, melting section 230-240℃, shearing section 250-260℃, venting section 230-240℃, and extrusion section 250-260℃. Through this melt extrusion process, the composite material can be obtained.

[0013] As a further aspect of the present invention, the specific preparation method of the macromolecular multi-component flame retardant is as follows:

[0014] The reactive phosphorus-based flame retardant and N,N-dimethylformamide are added to a nitrogen-filled polymerization reactor and stirred until a homogeneous reaction solution is formed. Then, a sulfur-containing chain extender and a phase transfer catalyst are added to the polymerization reactor. After the addition is complete, heating is started, and the temperature is raised to 100-120℃ at a controlled rate of 3-6℃ / min. The temperature is maintained and stirred continuously for 12-24 hours. After that, the nitrogen is removed, the solvent is evaporated and removed, heating is stopped, the material is cooled and discharged, and after purification, a macromolecular multi-component flame retardant can be obtained.

[0015] As a further aspect of the present invention, the specific preparation method of the reactive phosphorus-based flame retardant is as follows:

[0016] Aspartic acid, tri(2-chloroethyl) phosphate, and toluene solvent were added to a reaction vessel. After the addition was complete, stirring was started until a homogeneous mixture was formed. Nitrogen gas was then introduced for protection. An acid-binding agent was added to the reaction vessel, and then the heating program was started to maintain the temperature in the reaction vessel at 70-80°C. After stirring and reacting for 6-9 hours, heating was stopped, the product was separated, and the reactive phosphorus-based flame retardant was obtained through post-processing.

[0017] As a further embodiment of the present invention, the molar ratio of aspartic acid to tri(2-chloroethyl) phosphate is 1:1.

[0018] As a further embodiment of the present invention, the acid-binding agent is triethylamine.

[0019] As a further embodiment of the present invention, the sulfur-containing chain extender is 3,6-dithia-1,8-octanediol.

[0020] As a further embodiment of the present invention, the phase transfer catalyst is any one of aminosulfonic acid, trifluoromethanesulfonic acid, or p-toluenesulfonic acid.

[0021] In the above technical solution, aspartic acid and tri(2-chloroethyl) phosphate are first used as reactants. The active amino and active halogen substituents in their structures can undergo substitution reactions to prepare a reactive phosphorus flame retardant with a structure containing two equivalent carboxyl substituents. Then, under phase transfer catalyst and high temperature conditions, it can undergo a continuous condensation reaction with the hydroxyl substituents at both ends of the sulfur-containing chain extender to prepare a macromolecular multi-component flame retardant with a block structure linked by ester bonds.

[0022] As a further embodiment of the present invention, the antioxidant is at least one of antioxidant 1010, antioxidant 1076 or antioxidant 168; the coupling agent is at least one of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane or N-(2-aminoethyl)-3-aminopropyltrimethoxysilane.

[0023] As a further aspect of the present invention, the inorganic filler is at least one of calcium carbonate, talc, or silicon dioxide.

[0024] A flame-retardant nylon composite material is prepared using the above-described preparation method.

[0025] (III) Beneficial Technical Effects

[0026] This invention prepares a macromolecular multi-component flame retardant as an additive, which is then mixed with nylon 6 resin. On the one hand, the macromolecular multi-component flame retardant contains a large number of ester groups, which have good compatibility with nylon 6 and can effectively prevent its own migration and precipitation. On the other hand, the phosphorus and sulfur elements contained in its structure can act as acid sources, and nitrogen elements can act as gas sources, forming a synergistic flame retardant effect. During combustion, it can quickly form an expanding carbon layer, which highly isolates external oxygen and heat, thereby preventing the combustion from continuing to spread inward, thus significantly improving the flame retardant performance of the composite material. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is an infrared analysis test image of a macromolecular multi-component flame retardant. Detailed Implementation

[0029] To facilitate understanding of the present invention, a more complete description will be provided below. Preferred embodiments of the invention are given below. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0030] Preparation Example 1

[0031] Preparation of macromolecular multi-component flame retardants:

[0032] Step 1: Add 0.6g of aspartic acid, 1.29g of tri(2-chloroethyl) phosphate and toluene solvent to the reaction vessel. After the addition is complete, start stirring until a uniform mixture is formed. Then, purge with nitrogen for protection. Add 0.2g of triethylamine, an acid-binding agent, to the reaction vessel. Then, start the heating program and maintain the temperature in the reaction vessel at 75℃. After stirring and reacting for 8 hours, stop heating, separate the product, and after post-processing, the reactive phosphorus-based flame retardant can be obtained.

[0033] Step 2: Add 0.5g of reactive phosphorus-based flame retardant and N,N-dimethylformamide to a nitrogen-filled polymerization reactor and start stirring until a homogeneous reaction solution is formed. Then, add 0.24g of 3,6-dithia-1,8-octanediol and 0.01g of p-toluenesulfonic acid to the polymerization reactor. After the addition is complete, start heating and control the heating rate to 5℃ / min. Raise the temperature to 110℃ and maintain it. Continue stirring and polymerize for 18 hours. Then, remove the nitrogen, evaporate and remove the solvent, stop heating, cool down and discharge the material. After purification, the macromolecular multi-component flame retardant can be obtained.

[0034] Figure 1 This is the infrared analysis test image of the macromolecular multi-component flame retardant, where 3427 cm⁻¹... -1 The characteristic absorption peak appearing at 3309 cm⁻¹ is the characteristic absorption peak of NH in secondary amines. -1 The characteristic absorption peak appearing at 1745 cm⁻¹ is the characteristic absorption peak of hydroxyl groups. -1 The characteristic absorption peak appearing at 1251 cm⁻¹ is the characteristic absorption peak of the C=O group of the ester group. -1 The characteristic absorption peak appearing at this point is the P=O characteristic absorption peak.

[0035] Example 1

[0036] A flame-retardant nylon composite material comprising the following raw materials measured in parts by weight:

[0037]

[0038] The method for preparing the composite material includes the following steps:

[0039] Step 1: Weigh and prepare all the raw materials according to their weight proportions;

[0040] The second step involves adding all raw materials to a high-speed mixer, raising the temperature to 100℃, and mechanically mixing them at a stirring rate of 1000r / min for 60 minutes. Then, the mixture is transferred to a twin-screw extruder, and the extruder temperatures are controlled as follows: conveying section 195℃, melting section 235℃, shearing section 255℃, venting section 235℃, and extrusion section 255℃. After the melt extrusion process, the composite material can be obtained.

[0041] Example 2

[0042] A flame-retardant nylon composite material comprising the following raw materials measured in parts by weight:

[0043]

[0044]

[0045] The method for preparing the composite material includes the following steps:

[0046] Step 1: Weigh and prepare all the raw materials according to their weight proportions;

[0047] The second step involves adding all raw materials to a high-speed mixer, raising the temperature to 110°C, and mechanically mixing them at a stirring rate of 1200 r / min for 40 minutes. Then, the mixture is transferred to a twin-screw extruder, and the extruder temperatures are controlled as follows: conveying section 195°C, melting section 235°C, shearing section 255°C, venting section 235°C, and extrusion section 255°C. After the melt extrusion process, the composite material can be obtained.

[0048] Example 3

[0049] A flame-retardant nylon composite material comprising the following raw materials measured in parts by weight:

[0050]

[0051] The method for preparing the composite material includes the following steps:

[0052] Step 1: Weigh and prepare all the raw materials according to their weight proportions;

[0053] The second step involves adding all raw materials to a high-speed mixer, raising the temperature to 120°C, and mechanically mixing them at a stirring rate of 1500 r / min for 30 minutes. Then, the mixture is transferred to a twin-screw extruder, and the extruder temperatures are controlled as follows: conveying section 195°C, melting section 235°C, shearing section 255°C, venting section 235°C, and extrusion section 255°C. After the melt extrusion process, the composite material can be obtained.

[0054] Comparative Example 1

[0055] A flame-retardant nylon composite material comprising the following raw materials measured in parts by weight:

[0056]

[0057] The method for preparing the composite material includes the following steps:

[0058] Step 1: Weigh and prepare all the raw materials according to their weight proportions;

[0059] The second step involves adding all raw materials to a high-speed mixer, raising the temperature to 110°C, and mechanically mixing them at a stirring rate of 1200 r / min for 40 minutes. Then, the mixture is transferred to a twin-screw extruder, and the extruder temperatures are controlled as follows: conveying section 195°C, melting section 235°C, shearing section 255°C, venting section 235°C, and extrusion section 255°C. After the melt extrusion process, the composite material can be obtained.

[0060] Comparative Example 2

[0061] A flame-retardant nylon composite material comprising the following raw materials measured in parts by weight:

[0062]

[0063] The method for preparing the composite material includes the following steps:

[0064] Step 1: Weigh and prepare all the raw materials according to their weight proportions;

[0065] The second step involves adding all raw materials to a high-speed mixer, raising the temperature to 110°C, and mechanically mixing them at a stirring rate of 1200 r / min for 40 minutes. Then, the mixture is transferred to a twin-screw extruder, and the extruder temperatures are controlled as follows: conveying section 195°C, melting section 235°C, shearing section 255°C, venting section 235°C, and extrusion section 255°C. After the melt extrusion process, the composite material can be obtained.

[0066] Test case

[0067] The composite materials used in the examples and comparative examples were prepared into test specimens conforming to the test specifications. The limiting oxygen index was tested according to standard GB / T2406.1-2008, and the results are recorded in the table below:

[0068] Table 1 - Test Results

[0069] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Limiting oxygen index / % 32.3 32.6 32.5 27.1 24.6

[0070] According to the test results, the use of the macromolecular multi-element flame retardant prepared in Example 1 of this invention as an additive can significantly improve the flame retardant performance of nylon composite materials, while the flame retardant modification effect of conventional small-molecule dimethyl phosphite flame retardant is relatively poor.

[0071] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0072] Based on the preferred embodiments of the present invention, and through the above description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A method for preparing a flame-retardant nylon composite material, characterized in that, The composite material comprises the following raw materials measured in parts by weight: 65-75 parts of nylon 6 resin; 10-15 parts glass fiber; 3-5 parts of macromolecular multi-component flame retardant; Antioxidant 0.5-1.5 parts; 1-2 parts coupling agent; 5-10 parts of inorganic filler; The preparation method includes the following steps: Step 1: Weigh and prepare all the raw materials according to their respective weight proportions; The second step involves adding all raw materials to a high-speed mixer, raising the temperature to 100-120℃, and mechanically mixing them at a stirring rate of 1000-1500 r / min for 30-60 minutes. The mixture is then transferred to a twin-screw extruder, with the extruder temperatures controlled as follows: conveying section 190-200℃, melting section 230-240℃, shearing section 250-260℃, venting section 230-240℃, and extrusion section 250-260℃. Through this melt extrusion process, the composite material can be obtained. The specific preparation method of the macromolecular multi-component flame retardant is as follows: The reactive phosphorus-based flame retardant and N,N-dimethylformamide are added to a nitrogen-filled polymerization reactor and stirred until a homogeneous reaction solution is formed. Then, a sulfur-containing chain extender and a phase transfer catalyst are added to the polymerization reactor. After the addition is complete, heating is started, and the temperature is raised to 100-120℃ at a controlled rate of 3-6℃ / min. The temperature is maintained and stirred continuously for 12-24 hours. After that, the nitrogen is removed, the solvent is evaporated and removed, heating is stopped, the material is cooled and discharged, and after purification, a macromolecular multi-element flame retardant can be obtained. The specific preparation method of the reactive phosphorus-based flame retardant is as follows: Aspartic acid, tri(2-chloroethyl) phosphate, and toluene solvent were added to a reaction vessel. After the addition was complete, stirring was started until a homogeneous mixture was formed. Nitrogen gas was then introduced for protection. An acid-binding agent was added to the reaction vessel, and then the heating program was started to maintain the temperature in the reaction vessel at 70-80°C. After stirring and reacting for 6-9 hours, heating was stopped, the product was separated, and the reactive phosphorus-based flame retardant was obtained through post-processing.

2. The method for preparing a flame-retardant nylon composite material according to claim 1, characterized in that, The molar ratio of aspartic acid to tri(2-chloroethyl) phosphate is 1:

1.

3. The method for preparing a flame-retardant nylon composite material according to claim 1, characterized in that, The acid-binding agent is triethylamine.

4. The method for preparing a flame-retardant nylon composite material according to claim 1, characterized in that, The sulfur-containing chain extender is 3,6-dithia-1,8-octanediol.

5. The method for preparing a flame-retardant nylon composite material according to claim 1, characterized in that, The phase transfer catalyst is any one of aminosulfonic acid, trifluoromethanesulfonic acid, or p-toluenesulfonic acid.

6. The method for preparing a flame-retardant nylon composite material according to claim 1, characterized in that, The antioxidant is at least one of antioxidant 1010, antioxidant 1076, or antioxidant 168; the coupling agent is at least one of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, or N-(2-aminoethyl)-3-aminopropyltrimethoxysilane.

7. A flame-retardant nylon composite material, characterized in that, It is prepared by the preparation method described in any one of claims 1-6.

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