Filled flame-retardant nylon 6 material as well as preparation method and application thereof

Abstract

The invention discloses a filled flame-retardant nylon 6 material and a preparation method and application thereof, and relates to the technical field of filled flame-retardant nylon 6 materials, and the filled flame-retardant nylon 6 material is prepared by melt blending of the following raw materials: nylon 6, calcium sulfate whiskers, fully vulcanized rubber powder, a flame retardant and an auxiliary agent; the nylon 6 composite material comprises the following components in parts by weight: 100 parts of nylon 6; 1-50 parts by weight of calcium sulfate whisker; 1-50 parts by weight of fully vulcanized rubber powder; 1-30 parts by weight of a flame retardant; and 0.1-1 part by weight of an auxiliary agent. The filled flame-retardant nylon 6 material disclosed by the invention can be effectively applied to rapid forming, such as the fields of household appliances, automobiles, electronics and the like, and the addition of the anhydrous crystal whiskers not only contributes to the physical properties of the material, but also can play a better hydrophobic effect, and effectively makes up the performance defects of the nylon 6 material.

Description

Technical Field

[0001] The invention relates to the technical field of filled flame-retardant nylon 6 materials, and further to a filled flame-retardant nylon 6 material and a preparation method and application thereof. Background Art

[0002] 3D printing (3D Pirnitgn) technology, also known as rapid prototyping technology, rapid prototyping manufacturing (RPM), and additive manufacturing technology, is a high-tech manufacturing technology based on material accumulation. It is a technology that uses powdered metal or plastic and other bondable materials to construct objects by printing layer by layer based on digital model files. It integrates mechanical engineering, CAD, reverse engineering technology, layered manufacturing technology, numerical control technology, and material science, and is known as "a manufacturing technology with industrial revolutionary significance." Through high-intensity laser irradiation, the material powder pre-laid on the workbench or parts is selectively melted and sintered layer by layer to achieve layer-by-layer molding. 3D technology has a high degree of design flexibility, can produce accurate models and prototypes, can form parts with reliable structures that can be used directly, and has a short production cycle and simple process, so it is particularly suitable for the development of new products. Although there are many types of applicable molding materials, there are few polymer powder raw materials that can be directly applied to 3D technology for automotive parts and successfully produce molded products with small dimensional errors, regular surfaces, and low porosity. 3D molding mainly includes a variety of 3D printing technologies including fused deposition modeling (FDM), selective laser sintering (SLS), stereolithography (SLA), etc., which greatly expands the methods of material molding. Especially for materials that cannot be molded by melt processing, 3D printing is a good solution. At present, the most common 3D printing materials on the market are PP, PE, ABS, PLA and other materials. With the promotion of 3D printing technology, the demand for more and more complex and demanding aviation, electronics, automobiles and other fields is increasing. Among them, nylon 6 material is also increasingly widely used due to its unique properties. In practical applications, due to the existence of friction and wear, this has become a top priority for equipment use and maintenance. By adding lubricating materials, the friction and wear of nylon materials can be effectively reduced, which is our main direction in the process of material modification and processing.

[0003] Polycaprolactam, also known as nylon 6 (PA6), has high wear resistance, good lubrication, good oil resistance, chemical resistance and other characteristics, and the special functions it has through modification. It has a significant effect in replacing metal materials. As a new type of engineering plastic, nylon 6 and its modified varieties have great application value and broad industrial prospects. Nylon 6 is obtained by hydrolyzing caprolactam monomer at high temperature to obtain aminocaproic acid, and then polymerizing it at high temperature. It is a translucent or opaque milky white particle with the characteristics of thermoplasticity, light weight, good toughness, chemical resistance and durability. Nylon 6 has a low melting point and a wide process temperature range. Its impact resistance and solubility resistance are better than nylon 66 plastic, but its hygroscopicity is also stronger. Because many quality characteristics of plastic parts are affected by hygroscopicity, this should be fully considered when designing products using nylon 6. In order to improve the mechanical properties of nylon 6, various modifiers are often added. Conventional modifications of nylon 6 materials mainly include reinforcement, filling, flame retardancy and other processes. By adding the first and second components, the physical properties of nylon 6 materials are improved and the application areas of nylon 6 materials are broadened.

[0004] Patent 200710172953.6 discloses a glass fiber reinforced nylon 6-polypropylene alloy material, which is characterized by using nylon 6 and polypropylene as the base resin. Under the condition that the content of toughening agent (anhydride grafted elastomer and polyethylene or polypropylene polymer) remains unchanged, the mechanical properties of single reinforced nylon 6 without adding polypropylene can be achieved and even better through glass fiber reinforcement. Patent CN106700522A uses PA6, MgCO 3 Interface modifier and bisphenol A epoxy resin, MgCO 3The complex system formed by the complex reaction with PA6 has a lower melting point, and the bisphenol A epoxy resin added therein can react with the PA6 molecular chain, thereby improving the problem of poor impact resistance of pure PA6. Patent 200710172953.6 discloses a glass fiber reinforced nylon 6-polypropylene alloy material, which is characterized in that nylon 6 and polypropylene are used as the matrix resin. Under the condition that the content of toughening agent (anhydride grafted elastomer and polyethylene or polypropylene polymer) remains unchanged, the mechanical properties of single-reinforced nylon 6 without adding polypropylene can be achieved and surpassed by glass fiber reinforcement. Patent 99109924.9 proposes a method for preparing a polyamide / polypropylene alloy, which adopts ethylene-octene copolymer elastomer grafted with maleic anhydride as the third component to prepare a polyamide 6 / polypropylene alloy material, which not only combines the advantages of nylon 6 and polyolefin, but also has high impact toughness. All of the above patents use maleic anhydride as a compatibilizer, or a third component, to increase the compatibility between olefin materials and nylon to obtain better mechanical properties. In traditional filled flame-retardant nylon materials, in order to simplify the processing technology, the pre-blending method is mainly adopted. Such disadvantages exist directly in the preparation process of the material, thus affecting the physical properties of the material.

[0005] At present, most polyamides are fiber manufacturers, and resin production is relatively small. Most products have low viscosity. Nylon 6 has made great progress in the fields of automotive product manufacturing, electronics and electrical appliances, mechanical products, packaging industry, construction industry, etc. It has an indispensable position in my country's modernization construction and development. It has excellent mechanical properties and can replace metal for automotive structural parts to reduce vehicle weight. Or used for other industrial applications or daily uses. High molecular weight nylon generally has relatively excellent mechanical properties. At the same time, the number of nylon terminal functional groups and oligomer content have an impact on nylon performance. With the improvement of people's living standards, people have more stringent requirements for hygiene and environmental protection. While requiring material performance, they also pay more attention to the environmental protection and safety performance of materials. In the industrial field of nylon material application, flame retardant performance requirements have become the norm. Halogen-free flame retardant nylon materials have become people's normal requirements for flame retardant nylon. Traditionally, adding flame retardant additives to flame retardant nylon has a greater impact on the flame retardant properties of the material. The physical properties of the obtained material are often significantly reduced, and there are also great difficulties in the processing of the material. Summary of the invention

[0006] In order to solve the problems existing in the prior art, the present invention provides a filled flame-retardant nylon 6 material and a preparation method and application thereof. The filled flame-retardant nylon 6 material of the present invention can be effectively used in rapid prototyping, such as home appliances, automobiles, electronics and other fields. The addition of anhydrous whiskers not only helps the physical properties of the material, but also has a good hydrophobic effect, effectively making up for the performance defects of the nylon 6 material.

[0007] One of the objects of the present invention is to provide a filled flame retardant nylon 6 material.

[0008] The filled flame-retardant nylon 6 material of the present invention is prepared by melt blending raw materials including the following components:

[0009] Nylon 6, calcium sulfate whiskers, fully vulcanized rubber powder, flame retardants and additives;

[0010] Each component is calculated by weight:

[0011]

[0012]

[0013] Preferably,

[0014] Each component is calculated by weight:

[0015]

[0016] Nylon 6 has good strength, but it is easy to absorb water and crystallize slowly after filling and toughening, which often causes loss and long processing cycle when used in nylon 6 parts. In order to increase the market of nylon 6 and expand its application areas, adding fully vulcanized rubber powder not only improves the toughness of the material, but also allows flame retardants, additives, and calcium sulfate whiskers to be evenly mixed into nylon 6 materials, thereby effectively integrating nylon 6, calcium sulfate whiskers, and fully vulcanized rubber powder.

[0017] Preferably,

[0018] The agglomerated particle size of the fully vulcanized rubber powder is 10 to 50 microns, and is added into a nylon 6 matrix and dispersed into nano-scale micro-particles.

[0019] Preferably,

[0020] The calcium sulfate whiskers are fibrous single crystal materials of anhydrous calcium sulfate; preferably, the average diameter of the calcium sulfate whiskers is 1-8 um, and / or the average length is 30-200 um, and / or the aspect ratio is 100-150; more preferably, the calcium sulfate whiskers are anhydrous calcium sulfate whiskers or hemihydrate calcium sulfate whiskers.

[0021] Calcium sulfate whiskers are added to the matrix as nylon 6 filling materials. They combine the advantages of reinforcing fibers and inorganic fillers. They have many excellent physical and chemical properties such as high strength, high modulus, high toughness, high insulation, wear resistance, high temperature resistance, corrosion resistance, easy surface treatment, easy to composite with polymers, and non-toxicity.

[0022] Preferably,

[0023] The molecular weight of the nylon 6 is 10,000-210,000; and / or,

[0024] The viscosity of the nylon 6 is 2.0-3.2; and / or,

[0025] The molar content of the terminal functional groups of the nylon 6 is 10-12%. Since the total amount of the molecular weight and the number of terminal groups is fixed, the two amounts are inversely proportional, so the larger the molecular weight, the smaller the number of terminal groups. After the molecular weight is determined, the number of functional groups is also fixed; and / or,

[0026] The oligomer content of the nylon 6 is 0.1-2%.

[0027] The high molecular weight nylon 6 used in the present invention has excellent mechanical properties. According to the viscosity of nylon, nylon 6 is divided into low viscosity, medium viscosity and high viscosity nylon 6. The viscosity of the nylon 6 base material of the present invention selects medium viscosity, so that the material can be applied to a wider range of fields. The number of terminal functional groups and the content of oligomers in the nylon material have an impact on the nylon performance: the terminal functional groups of nylon 6 determine the activity of the material in the modification process, and the modification requirements can be well met by adding materials containing polar functional groups such as fully vulcanized rubber powder and calcium sulfate whiskers; oligomers, as polymerization byproducts of nylon, have a direct impact on the performance of nylon materials. Preventing and reducing the generation of oligomers in the polymerization process can effectively improve the performance of nylon materials.

[0028] Preferably,

[0029] The flame retardant is melamine, which has a significant flame retardant effect on nylon materials. Very good effects can be achieved by adding very little melamine, and its addition amount is only half of other flame retardants. Melamine flame retardant belongs to phosphate ester compounds, and the flame retardant material has a low smoke and low toxicity flame retardant effect. Although it is difficult to disperse in the material, the present invention can effectively complete its dispersion effect by adding fully vulcanized rubber powder; and / or,

[0030] The auxiliary agent is polyethylene glycol, which plays the role of a protective layer during the preparation process and can reduce the friction between the calcium sulfate whiskers and the screw, which is an effect that other lubricating auxiliary agents cannot achieve.

[0031] Conventional additives such as antioxidants, fillers and lubricants can be added to the formula of the present invention according to actual conditions. The amounts used are conventional amounts and can be added by technicians according to actual conditions. The fillers are usually inorganic fillers, such as talcum powder, barium sulfate, calcium carbonate, mica, wollastonite, etc. The antioxidant is preferably an antioxidant for nylon.

[0032] The second object of the present invention is to provide a method for preparing a filled flame-retardant nylon 6 material.

[0033] The preparation method of the filled flame-retardant nylon 6 material of the present invention comprises:

[0034] Nylon 6, a flame retardant and fully vulcanized rubber powder are premixed, and then calcium sulfate whiskers and an auxiliary agent are added for melt blending to obtain the filled flame-retardant nylon 6 material.

[0035] Preferably,

[0036] The stirring speed of the premix is ​​100 to 180 rpm, and / or the stirring temperature is 20 to 50° C., and / or the stirring time is 1 to 3 minutes.

[0037] Preferably,

[0038] The temperature of the melt blending is 220-250° C., and / or the blending time is 30-40 seconds, and / or the stirring speed is 100-300 rpm.

[0039] Among them, melt blending refers to the blending of raw materials in a twin-screw extruder. The processing temperature of the twin-screw extruder is 220-250°C, the main engine speed is controlled at 100-300 rpm, and the raw materials stay in the screw for 30-40 seconds.

[0040] The following solutions can be adopted:

[0041] The invention makes an advance judgment on the problems that are likely to occur in the material processing process, and adopts a twin-screw extruder to prepare a filled flame-retardant nylon 6 material: melamine and fully vulcanized rubber powder are added to the nylon 6 premix, mixed at low speed and low temperature for 1 to 3 minutes, and granulated by an extruder; in the melting section of the twin-screw extruder, calcium sulfate whiskers and polyethylene glycol are added through a lateral sizing device, so that in this process, the calcium sulfate whiskers and polyethylene glycol can be smoothly added to the barrel, the particle size of the calcium sulfate whiskers can be completely maintained, and the calcium sulfate whiskers can smoothly enter the barrel cavity under the protection of the polyethylene glycol, so that the contact surface between the material and the screw barrel is reduced, the production energy consumption is reduced, and the calcium sulfate whiskers are ensured to be evenly dispersed in the nylon 6, so as to obtain the required filled flame-retardant nylon 6 material.

[0042] The third object of the present invention is to provide an application of a filled flame-retardant nylon 6 material in 3D printing technology.

[0043] Nylon materials are widely used as 3D printing materials due to their good physical properties. However, due to the structural problems of nylon 6 itself, its application in the field of 3D printing has great limitations, mainly because the shrinkage rate of the material is large. During the application of the material, due to its rapid crystallization, there will be stress concentration during molding, which is easy to cause cracking, and there are also problems such as a long molding cycle. The present invention uses fully vulcanized rubber powder, melamine and other materials to effectively make up for the problems of nylon 6 crystallization and flame retardancy.

[0044] The invention can effectively fill the gaps in the flame-retardant nylon 6 material by adding fully vulcanized rubber powder and polyethylene glycol; the calcium sulfate whisker and polyethylene glycol are directly added to the melting section of the twin-screw extruder by the side feeding method, so as to ensure that the aspect ratio loss of the calcium sulfate whisker is reduced to the minimum; when the raw materials enter the box melting section of the twin-screw extruder, under the action of the reverse kneading and other screw blocks, the melting effect between the raw materials is greatly improved.

[0045] The filled flame-retardant nylon 6 material of the present invention not only has a high flame-retardant effect, but also has a great improvement in toughness and strength, which makes up for the shortcomings of the filled flame-retardant nylon material such as insufficient toughness and easy cracking. Calcium sulfate whiskers and fully vulcanized rubber powder can effectively change the crystallization effect of nylon 6, play a good bridge role between nylon 6 and flame retardants, and also improve the molding effect of the material and reduce the shrinkage rate. Among them, the addition of calcium sulfate whiskers not only plays an effect in physical properties, but also plays a good hydrophobic property, which makes up for the defects of nylon 6 and has significant advantages in 3D rapid prototyping. The filled flame-retardant nylon 6 material of the present invention is applied in rapid prototyping, which can be effectively applied in the fields of home appliances, automobiles, electronics, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 This is a SEM image of the filled flame-retardant nylon 6 material prepared in Example 3;

[0047] Figure 2 This is a SEM image of the flame-retardant nylon 6 material prepared in Comparative Example 2;

[0048] Depend on Figure 1 and Figure 2 From the comparison, it can be seen that the present invention uses melamine as a flame retardant to achieve effective flame retardant effect. Melamine is a phosphate compound with low smoke and low toxicity flame retardant effect. Although it is difficult to disperse in the material, the present invention achieves good dispersion by adding fully vulcanized rubber powder. The scanning electron microscope photo shows that the material is evenly dispersed. DETAILED DESCRIPTION

[0049] The present invention is described in detail below in conjunction with specific drawings and embodiments. It is necessary to point out that the following embodiments are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made to the present invention by those skilled in the art based on the content of the present invention still fall within the scope of protection of the present invention.

[0050] The raw materials and equipment used in the examples and comparative examples of the present invention are all commercially available, and the specific information is as follows:

[0051] Raw materials used in the experiment:

[0052] Fully vulcanized rubber powder, ultrafine fully vulcanized styrene-butadiene rubber, rubber powder agglomerate particle size 10-50 microns Beijing Chemical Research Institute

[0053] Polyethylene glycol experimental grade, molecular weight 6000 Beijing Research Institute of Chemical Industry

[0054] Nylon 6 medium viscosity, molecular weight 28,000, terminal functional groups between 10% and 12%, oligomer content about 2% Sinopec Baling Petrochemical Company

[0055] Nylon 6 has high viscosity, molecular weight of 210,000, terminal functional groups between 10% and 12%, and oligomer content of about 2%. Sinopec Baling Petrochemical Company

[0056] Melamine Beijing Xinkeao Company

[0057] Anhydrous calcium sulfate whiskers conventional, model: 100-150 aspect ratio, average diameter 1-8um, average length 30-200um Jiangsu Xinyuan Mining Company

[0058] Antioxidant 1010 BASF-Ciba, Germany

[0059] Talc 1250 mesh Beijing Xinkeao Company

[0060] Flame retardant HTCTP is commercially available

[0061] Grafted POE 8150 Beijing Xinkeao Company

[0062] Equipment used in the experiment:

[0063] Twin screw extruder Coperion

[0064] High speed agitator Beijing Plastic Machinery Factory

[0065] Injection Machine Ningbo Haitian Machinery Factory

[0066] Examples 1-6

[0067] The amount of raw materials used in Examples 1-6 is shown in Table 1. Nylon 6, melamine and fully vulcanized rubber powder are premixed in a high-speed stirrer at 180 rpm and 20-50°C for 2 minutes, and calcium sulfate whiskers and polyethylene glycol are added into the melting section of the twin-screw extruder by forced conveying and side feeding of a twin-screw extruder. The processing temperature of the twin-screw extruder is 220-230°C in the melting section and 220-230°C in the homogenizing section. The main engine speed is controlled at 300 rpm. The raw materials are melt-blended for 30-40 seconds in the compression section and the reverse kneading section inside the barrel, and the wire is drawn through a die and cooled and granulated in a water tank to obtain the required filled flame-retardant nylon 6 material. Among them, the nylon 6 used in Examples 1-5 is medium-viscosity nylon 6, and the nylon 6 used in Example 6 is high-viscosity nylon 6.

[0068] Table 1 (Unit: parts by weight)

[0069] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Nylon 6 100 100 100 100 100 100 Polyethylene glycol 1 1 1 0.1 0.5 1 Calcium sulfate whiskers 30 15 10 10 10 10 Melamine 5 10 10 10 10 10 Fully vulcanized rubber powder 1 5 10 10 10 10 Antioxidant 1010 0.15 0.15 0.15 0.15 0.15 0.15

[0070] Comparative Example 1

[0071] 100 parts by weight of medium viscosity nylon 6, 10 parts by weight of grafted POE, and 0.15 parts by weight of antioxidant 1010 are premixed in a high-speed stirrer at 180 rpm at 20-50° C. for 2 minutes, added into a twin-screw extruder, and extruded and granulated at a main engine speed of 300 rpm. 10 parts by weight of talcum powder and 10 parts by weight of flame retardant HTCTP are premixed in a high-speed stirrer at 180 rpm at 20-50° C. for 2 minutes, and forcedly added into the melting section of the twin-screw extruder by a twin-screw forced conveying and side feeding method. The processing temperature of the twin-screw extruder is 220-230° C. in the melting section and 220-230° C. in the homogenizing section. The main engine speed is controlled at 300 rpm. The raw materials are melt-blended in the compression section and the reverse kneading section inside the barrel for 30-40 seconds, and the wires are drawn through a die and cooled and granulated in a water tank to obtain the required flame-retardant nylon 6 material.

[0072] Comparative Example 2

[0073] 100 parts by weight of medium viscosity nylon 6, 10 parts by weight of grafted POE, and 0.15 parts by weight of antioxidant 1010 are premixed in a high-speed stirrer at 180 rpm at 20-50° C. for 2 minutes, added into a twin-screw extruder, and extruded and granulated at a main engine speed of 300 rpm. 20 parts by weight of talcum powder and 10 parts by weight of flame retardant HTCTP are premixed in a high-speed stirrer at 180 rpm at 20-50° C. for 2 minutes, and forcedly added into the melting section of the twin-screw extruder by a twin-screw forced conveying and side feeding method. The processing temperature of the twin-screw extruder is 220-230° C. in the melting section and 220-230° C. in the homogenizing section. The main engine speed is controlled at 300 rpm. The raw materials are melt-blended in the compression section and the reverse kneading section inside the barrel for 30-40 seconds, and the wires are drawn through a die and cooled and granulated in a water tank to obtain the required flame-retardant nylon 6 material.

[0074] Comparative Example 3

[0075] 100 parts by weight of medium viscosity nylon 6, 10 parts by weight of grafted POE, and 0.15 parts by weight of antioxidant 1010 are premixed in a high-speed stirrer at 180 rpm at 20-50° C. for 2 minutes, added into a twin-screw extruder, and extruded and granulated at a main engine speed of 300 rpm. 20 parts by weight of calcium sulfate whisker and 10 parts by weight of melamine are premixed in a high-speed stirrer at 180 rpm at 20-50° C. for 2 minutes, and forcedly added into the melting section of the twin-screw extruder by a twin-screw forced conveying and side feeding method. The processing temperature of the twin-screw extruder is 220-230° C. in the melting section and 220-230° C. in the homogenizing section. The main engine speed is controlled at 300 rpm. The raw materials are melt-blended in a compression section and a reverse kneading section inside the barrel for 30-40 seconds, and the threads are drawn through a die and cooled and granulated in a water tank to obtain the required flame-retardant nylon 6 material. Among them, the toughening agent used in the comparative example is maleic anhydride grafted POE material, which has a market price of about 18,000 yuan / ton. The raw material dosages of comparative examples 1-3 are shown in Table 2.

[0076] Table 2 (Unit: parts by weight)

[0077] Comparative Example 1 Comparative Example 2 Comparative Example 3 Medium viscosity nylon 6 100 100 100 Talc 1250 10 20 Calcium sulfate whiskers 20 Flame retardant HTCTP 10 10 Melamine 10 Grafted POE 10 10 10 Antioxidant 1010 0.15 0.15 0.15

[0078] After the pellets prepared in the embodiment and the comparative example were added to the injection molding machine for injection molding (the temperatures of each section of the injection molding machine were 225°C, 240°C, 250°C, 250°C, 230°C, the holding pressure was 50MPa, the holding time was 60s, and the cooling time was 10s), the injection molded samples were prepared and their performance was tested. The physical properties of the samples were tested according to national standards: the tensile strength was tested according to GB / T1040-2006; the simply supported beam notched impact strength was tested according to GB / T 1043-1993; the shrinkage rate was tested according to GB / T 17037.4-2003; the test results are shown in Table 3 below.

[0079] Table 3

[0080]

[0081] It can be seen from the results in Table 3 that, compared with the comparative example, the crystallization rate of the flame-retardant nylon 6 material filled in the embodiment of the present invention has changed significantly, and the shrinkage rate of the material has been significantly reduced. In the application of 3D materials, the dimensional stability of the material can be ensured, and the apparent quality of the product is improved. Calcium sulfate whiskers and fully vulcanized rubber powder can melt nylon 6 and flame retardants well, so that the strength and toughness of the prepared material are greatly improved. Figure 1The SEM image can clearly show the toughening and flame retardant effect between the material interfaces. The small holes in the material can be clearly seen in the material interface. These small holes play a good barrier role in flame retardancy and can ensure the stable melting of the material during the use of 3D materials. Compared with talcum powder, the use of calcium sulfate whiskers can show the characteristics and advantages of whisker materials in both preparation process and experimental results. From the perspective of experimental process, the experimental process using melamine flame retardant is simpler and easier than that of flame retardant HTCTP. This is because HTCTP flame retardant additive is an organic phosphorus halogen compound flame retardant with a low melting temperature. When making flame retardant materials, since the screw barrel temperature is above 200°C, when adding materials, serious bridging phenomenon is likely to occur at the feed port, which affects continuous production and usually requires lateral auxiliary addition to the twin-screw extruder; while melamine has good temperature resistance and low water solubility. Its flame retardant principle is to decompose at high temperature to produce phosphoric acid gas and nitrogen gas, thereby forming a carbonized layer to prevent the spread of flames. The decomposition temperature is greater than 300°C, and the processing process does not affect the surface finish of the substrate, which is more convenient for continuous production. And from the test results of comparative examples 1-3, it can be seen that the performance of the material with melamine added is significantly better than that of the material with flame retardant HTCTP added.

Claims

1. A flame-retardant nylon 6 filled material, characterized in that The filled flame-retardant nylon 6 material is prepared by melt blending raw materials including the following components: Nylon 6, calcium sulfate whiskers, fully vulcanized rubber powder, flame retardants and additives; Each component is calculated by weight: Nylon 6 100 parts by weight; 1-50 parts by weight of calcium sulfate whiskers; 1 to 50 parts by weight of fully vulcanized rubber powder; 1 to 30 parts by weight of flame retardant; The additive is 0.1 to 1 part by weight.

2. The filled flame-retardant nylon 6 material according to claim 1, characterized in that: Each component is calculated by weight: Nylon 6 100 parts by weight; 10-30 parts by weight of calcium sulfate whiskers; 5-10 parts by weight of fully vulcanized rubber powder; 5 to 10 parts by weight of flame retardant; The additive is 0.1 to 0.15 parts by weight.

3. The filled flame-retardant nylon 6 material according to claim 1, characterized in that: The agglomerated particle size of the fully vulcanized rubber powder is 10 to 50 microns.

4. The filled flame-retardant nylon 6 material according to claim 1, characterized in that: The calcium sulfate whiskers are fibrous single crystal materials of anhydrous calcium sulfate; preferably, the average diameter of the calcium sulfate whiskers is 1-8 um, and / or the average length is 30-200 um, and / or the aspect ratio is 100-150; more preferably, the calcium sulfate whiskers are anhydrous calcium sulfate whiskers or hemihydrate calcium sulfate whiskers.

5. The filled flame-retardant nylon 6 material according to claim 1, characterized in that: The molecular weight of the nylon 6 is 10,000-210,000; and / or, The viscosity of the nylon 6 is 2.0-3.2; and / or, The molar content of the terminal functional groups of the nylon 6 is 10 to 12%; and / or, The oligomer content of the nylon 6 is 0.1-2%.

6. The filled flame-retardant nylon 6 material according to claim 1, characterized in that: The flame retardant is melamine; and / or, The auxiliary agent is polyethylene glycol.

7. A method for preparing the filled flame-retardant nylon 6 material as claimed in any one of claims 1 to 6, characterized in that The method comprises: Nylon 6, a flame retardant and fully vulcanized rubber powder are premixed, and then calcium sulfate whiskers and an auxiliary agent are added for melt blending to obtain the filled flame-retardant nylon 6 material.

8. The preparation method according to claim 7, characterized in that: The stirring speed of the premix is ​​100 to 180 rpm, and / or the stirring temperature is 20 to 50° C., and / or the stirring time is 1 to 3 minutes.

9. The preparation method according to claim 7, characterized in that: The temperature of the melt blending is 220-250° C., and / or the blending time is 30-40 seconds, and / or the stirring speed is 100-300 rpm.

10. Use of the filled flame-retardant nylon 6 material according to any one of claims 1 to 6 or the filled flame-retardant nylon 6 material obtained by the preparation method according to any one of claims 7 to 9 in 3D printing technology.

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