A nylon composite and a method for producing the same

Abstract

The application discloses a nylon composite material and a preparation method thereof. The nylon composite material is prepared from 50-67 parts of reinforced nylon recycled material, 10-25 parts of toughened nylon recycled material, 3-5 parts of auxiliary toughened recycled material, 3-8 parts of high-end amino PA66 / 6T, 3-10 parts of industrial waste residue, 0.3-2 parts of a chain extender and 0.2-1 part of an anti-aging agent, wherein the reinforced nylon recycled material is high-iron or heavy-load line recovered track gauge baffle and track gauge block crushed material, the toughened nylon recycled material is common-iron line recovered baffle seat crushed material, and the auxiliary toughened recycled material is railway fastener system recovered height-adjusting pad crushed material. In the application, the nylon fastener recycled material in the railway system is used, the performance of each fastener material is fully utilized, and the reinforced nylon composite material with the advantages of environmental protection, high performance, simple processing and obvious price advantage is prepared.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of composite materials, and particularly relates to a nylon composite material and a preparation method thereof. BACKGROUND

[0002] With the rapid development of China's rail transit industry, various railway fastener products are used in large quantities. The railway fastener system is a part used to connect the rail and the sleeper (or other types of subgrade) on the track, also known as an intermediate connecting part. Its main function is to fix the rail on the sleeper, maintain the gauge, and prevent the longitudinal and transverse movement of the rail relative to the sleeper. The railway fastener system is crucial to ensuring the safe and stable operation of the railway, and it directly affects the safety and comfort of the railway. In these fastener systems, components such as gauge stop plates, gauge blocks, and height adjustment pads are made of thermoplastic polymer materials, including reinforced nylon, toughened nylon, and polyethylene. As the application time of the fasteners increases, various diseases will occur, affecting the safety of train operation, and the fasteners need to be replaced regularly. After more than ten years of operation, China's high-speed railway system is expected to replace hundreds of thousands of fasteners every year, and a large number of plastic parts will be replaced. If not properly handled, it will seriously affect environmental safety and not meet the internal requirements of China's green and sustainable development of high-speed railways.

[0003] The replaced products involve a variety of materials, and many manufacturers currently only handle a single type of product material, modify the crushed material with new raw materials, and mostly use the product as a recycled material, resulting in high overall product cost and low utilization rate.

[0004] Railway fastener nylon products have their own particularity, and the performance requirements of non-metallic parts and materials of the fasteners in China are clear, which ensures the consistency of the initial performance of various materials. The performance degradation of the replaced products is mainly caused by molecular chain rupture, water absorption and plasticization, and glass fiber and matrix resin peeling caused by mechanical fatigue damage, and all recycled raw materials are subjected to light and oxygen aging, resulting in an increase in polar groups, which further increases the water absorption of the recycled products and accelerates the performance degradation of the recycled products. How to utilize the above performance-degraded waste parts is a current problem. SUMMARY

[0005] In order to overcome the problems in the prior art, the present application provides a nylon composite material and a preparation method thereof, which fully utilizes the performance of each type of fastener material by considering the performance changes of the crushed materials of the replaced fasteners, and explores a new green way of handling railway waste non-metallic parts. An enhanced nylon composite material with environmental protection, high performance, simple processing, and obvious price advantage is prepared.

[0006] To solve the above technical problems, the technical scheme provided by the present application is as follows:

[0007] The application provides a nylon composite material prepared from the following raw materials by weight:

[0008] 50-67 parts of reinforced nylon recycled material, the reinforced nylon recycled material being high-iron or heavy-load line recycled track gauge baffle and track gauge block crushed material;

[0009] 10-25 parts of toughened nylon recycled material, the toughened nylon recycled material being common-iron line recycled baffle seat crushed material;

[0010] 3-5 parts of auxiliary toughened recycled material, the auxiliary toughened recycled material being railway fastener system recycled height-adjusting pad crushed material;

[0011] 3-8 parts of PA66 / 6T;

[0012] 3-10 parts of industrial waste residue, the industrial waste residue being fly ash;

[0013] 0.3-2 parts of chain extender;

[0014] 0.2-1 part of anti-aging agent.

[0015] The recycled track gauge baffle and track gauge block crushed material, the recycled baffle seat crushed material and the recycled height-adjusting pad crushed material used in the application have special properties due to performance attenuation of the recycled products caused by product working conditions and environment, mainly molecular chain rupture caused by mechanical fatigue damage, water absorption plasticization and performance reduction caused by glass fiber and matrix resin peeling, and all the recycled raw materials are subjected to light and oxygen aging, so that the number of polar groups increases, and the water absorption of the recycled products is further improved, and the performance attenuation of the recycled products is accelerated, therefore, the application also adds high-temperature nylon PA66 / 6T to improve the interfacial bonding force of the glass fiber, the filler and the matrix resin, and to reduce the subsequent water absorption rate of the recycled products and maintain high performance of the products; and the chain extender is used in cooperation to have an auxiliary effect on improving the viscosity of the material. Meanwhile, the melting point of the PA66 / 6T is similar to that of the matrix, and does not affect the processing technology.

[0016] As an optional implementation, in the nylon composite material provided by the application, the glass fiber content of the reinforced nylon recycled material is 30-35%, and the melting point is 250-270 DEG C.

[0017] The glass fiber content of the reinforced nylon recycled material is controlled to be 30-35%, and the melting point is controlled to be 250-270 DEG C, so that the purity of the recycled material and the performance of the subsequently prepared composite nylon material are most excellent.

[0018] As an optional implementation, in the nylon composite material provided by the application, the melting point of the toughened nylon recycled material is greater than 210 DEG C.

[0019] The melting point of the toughened nylon recycled material is controlled to be greater than 210 DEG C, so that the purity of the recycled material and the performance of the subsequently prepared composite nylon material are most excellent.

[0020] As an optional embodiment, in the nylon composite material provided by the application, the elongation at break of the auxiliary toughening recycled material is greater than 50%.

[0021] The elongation at break of the auxiliary toughening recycled material is controlled to be greater than 50%, so that the effect of the auxiliary toughening agent is most excellent.

[0022] As an optional embodiment, in the nylon composite material provided by the application, the particle size of the fly ash is 300-400 mesh.

[0023] As an optional embodiment, in the nylon composite material provided by the application, the end amino content of the PA66 / 6T is 50-80 mmol / Kg, and the melting point is 255-270℃.

[0024] In the application, the PA66 / 6T is a copolymer material, the melting point is adjustable and controllable, and is controlled to be close to that of the PA66 in the range, does not affect the processing technology, and the performance is also relatively stable, and the high end amino group helps to improve the compatibility of the glass fiber and the resin, so that the product performance is more excellent.

[0025] As an optional embodiment, in the nylon composite material provided by the application, the high-iron or heavy-load line recycled track gauge baffle and track gauge block broken material is treated by a surface treatment solvent, and the surface treatment solvent is configured by 20%-30% amino siloxane, 60%-80% ethanol and 10-20% water.

[0026] In the application, in order to solve the problem of performance attenuation of the recycled raw material product, the waste track gauge baffle and track gauge block in the recycled high-iron or heavy-load line nylon fastener system are treated by a surface treatment solvent, the broken track gauge baffle and track gauge block are regarded as fillers, the glass fiber is exposed after being broken, and the surface is treated, which helps to improve the interface performance of the glass fiber and the matrix resin. In the application, the main function of the surface treatment solvent is coupling, which is commonly used for treating fillers, but in the application, it is used for treating the reinforcing broken material, so that the compatibility of the glass fiber and the resin is improved, and the performance reduction caused by the peeling of the two is reduced.

[0027] As an optional embodiment, in the nylon composite material provided by the application, the chain extender is selected from one of an epoxy-functional chain extender, an oxazoline-based chain extender or a carbonate-functional chain extender.

[0028] As an optional embodiment, in the nylon composite material provided by the application, the anti-aging auxiliary agent is a mixture of antioxidant 1098, antioxidant 168 and heat-resistant special auxiliary agent H3336.

[0029] As an optional implementation, in the nylon composite material provided by the application, the volume ratio of the antioxidant 1098, the antioxidant 168 and the heat-resistant special additive H3336 mixture is 1:1:1.

[0030] Based on the same technical concept, the application further provides a preparation method of the above-mentioned nylon composite material, comprising the following steps:

[0031] S1, recovering the discarded track gauge baffle and track gauge block in the high-iron or heavy-load line nylon fastener system, crushing and drying after removing oil stains and impurities, and obtaining the reinforced nylon regenerated material after drying.

[0032] S2, recovering the discarded baffle seat in the general-iron line, crushing and drying after removing oil stains and impurities, and obtaining the toughened nylon regenerated material.

[0033] S3, recovering the discarded height-adjusting pad in the railway fastener system, crushing and drying after removing oil stains and impurities, and obtaining the auxiliary toughened regenerated material.

[0034] S4, uniformly mixing the reinforced nylon regenerated material, the toughened nylon regenerated material, the auxiliary toughened regenerated material, PA66 / 6T, industrial waste residue, a chain extender and an anti-aging agent according to the mass fraction, melting and extruding through a double-screw extruder, and cutting into particles, so as to obtain the nylon composite material.

[0035] As an optional implementation, in the preparation method provided by the application, the discarded track gauge baffle and track gauge block are crushed to a particle size of ≤10 mm, the discarded baffle seat is crushed to a particle size of ≤10 mm, and the discarded height-adjusting pad is crushed to a particle size of ≤10 mm.

[0036] As an optional implementation, in the preparation method provided by the application, in step S2, the working temperature of the double-screw extruder is 245-280℃, and a ZME tooth-shaped mixing element is used in the screw combination.

[0037] Compared with the prior art, the application has the following beneficial effects:

[0038] (1) The nylon composite material of the application uses resin raw materials from discarded old parts of railway fasteners, and uses mineral fillers from industrial waste residues, so that the application has the characteristics of green environmental protection and obvious cost advantage.

[0039] (2) The raw materials used in the railway non-metal fasteners have unified iron standard regulations, uniform initial performance, and the performance change of discarded products is also basically close, so that the stability of the regenerated material is ensured, and at the same time, the replacement products of each line maintenance are concentrated and large in quantity, which is convenient for recycling and reliable in source.

[0040] (3) Through various recycled material key performance control, combined with modification technology, and mixed according to different proportions, the prepared nylon composite material has excellent mechanical properties, and the injection molded product has good appearance and low warpage deformation.

[0041] (4) The application can effectively overcome the recycling drawbacks of the performance attenuation of the fastener nylon by surface treatment of the reinforced nylon recycled material, addition of high-end amino content PA66 / 6T and chain extension under the action of the chain extender, and improve the comprehensive performance of the nylon composite material and product. DETAILED DESCRIPTION

[0042] In order to facilitate the understanding of the present application, the present application will be described in more detail below in conjunction with the description and preferred embodiments, but the protection scope of the present application is not limited to the following specific embodiments.

[0043] Unless otherwise defined, all the professional terms used herein have the same meaning as generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing the specific embodiments and are not intended to limit the protection scope of the present application.

[0044] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present application can be purchased from the market or can be prepared by existing methods.

[0045] Example 1

[0046] The preparation of the nylon composite material includes the following steps:

[0047] (1) The high-iron or heavy-load line recycled nylon fastener, including the waste track gauge baffle and the track gauge block, is removed of oil stains and impurities, crushed to a particle size of less than 10 mm, then dried and mixed, and the mixed material is directly injection molded into a test sample, the test sample is tested to have a glass fiber content of 30-35%, a melting point of 250-270℃, then a surface treatment solvent of 30% amino silicone, 60% ethanol and 10% water is slowly added to the qualified crushed material in the high-speed mixer at a proportion of 2% and stirred for 5-10 minutes, and finally dried at 120℃ for 2h to obtain the reinforced nylon recycled material.

[0048] (2) The waste baffle seat product recycled from the light rail line is removed of oil stains and impurities, crushed to a particle size of less than 1cm, then dried and mixed, and the mixed material is directly injection molded into a test sample, the test sample is tested to have a melting point of greater than 210℃, and the toughened nylon recycled material is obtained for use.

[0049] (3) The railway fastener system waste products of different thicknesses of height adjustment pads are removed of oil stains and impurities, crushed to a particle size of less than 1cm, then dried and mixed, and the mixed material is directly injection molded into a test sample, the test sample is tested to have an elongation at break of more than 50%, and the auxiliary toughened recycled material is obtained for use.

[0050] (4) Take the above-mentioned reinforced nylon recycled material 67 parts, toughening nylon recycled material 13.4 parts, PA66 / 6T with amino end group content of 50-80 mmol / Kg and melting point of 255-270°C 7 parts, auxiliary toughening recycled material 3 parts, fly ash 8 parts, Bruggemann M1251 chain extender 1 part, anti-aging aid 0.6 parts (1098:168:H3336=1:1:1), mix uniformly, melt extrude through double screw extruder 245-280°C, cut into particles, use ZME tooth-shaped mixing element in screw combination, to prepare nylon composite material.

[0051] Example 2

[0052] Take the reinforced nylon recycled material prepared in Example 1 67 parts, toughening nylon recycled material 17.4 parts, PA66 / 6T with amino end group content of 50-80 mmol / Kg and melting point of 255-270°C 3 parts, auxiliary toughening recycled material 3 parts, fly ash 8 parts, Bruggemann M1251 chain extender 1 part, anti-aging aid 0.6 parts (1098:168:H3336=1:1:1), mix uniformly, melt extrude through double screw extruder 260-280°C, cut into particles, use ZME tooth-shaped mixing element in screw combination, to prepare nylon composite material.

[0053] Example 3

[0054] Take the reinforced nylon recycled material prepared in Example 1 60.4 parts, toughening nylon recycled material 20 parts, PA66 / 6T with amino end group content of 50-80 mmol / Kg and melting point of 255-270°C 7 parts, auxiliary toughening recycled material 3 parts, fly ash 8 parts, Bruggemann M1251 chain extender 1 part, anti-aging aid 0.6 parts (1098:168:H3336=1:1:1), mix uniformly, melt extrude through double screw extruder 245-280°C, cut into particles, use ZME tooth-shaped mixing element in screw combination, to prepare nylon composite material.

[0055] Example 4

[0056] Take the reinforced nylon recycled material 67.4 parts (the difference from Example 1 is that it is not treated with surface treatment solvent containing aminosiloxane 30%, ethanol 60%, water 10%), toughening nylon recycled material prepared in Example 1 13 parts, auxiliary toughening recycled material 3 parts, PA66 / 6T with amino end group content of 50-80 mmol / Kg and melting point of 255-270°C 7 parts, fly ash 8 parts, Bruggemann M1251 chain extender 1 part, anti-aging aid 0.6 parts (1098:168:H3336=1:1:1), mix uniformly, melt extrude through double screw extruder 245-280°C, cut into particles, use ZME tooth-shaped mixing element in screw combination, to prepare nylon composite material.

[0057] Comparative Example 1

[0058] The reinforced nylon recycled material prepared in Example 1 was mixed with 70 parts, the toughened nylon recycled material was mixed with 30 parts, and then the mixture was uniformly mixed and melt-extruded through a double-screw extruder at 245-280°C, and the mixture was cut into particles. In the screw combination, a ZME tooth-shaped mixing element was used to prepare a nylon composite material.

[0059] Comparative Example 2

[0060] The reinforced nylon recycled material prepared in Example 1 was mixed with 67 parts, the toughened nylon recycled material was mixed with 20.4 parts, the auxiliary toughened recycled material was mixed with 3 parts, the fly ash was mixed with 8 parts, the Bruggemann M1251 chain extender was mixed with 1 part, and the anti-aging additive was mixed with 0.6 parts (1098:168: H3336 = 1:1:1). Then the mixture was uniformly mixed and melt-extruded through a double-screw extruder at 245-280°C, and the mixture was cut into particles. In the screw combination, a ZME tooth-shaped mixing element was used to prepare a nylon composite material.

[0061] The performance of the nylon composite material prepared in the examples and comparative examples was detected, and the detection results are shown in Table 1.

[0062] Table 1: Performance detection of products in examples and comparative examples

[0063]

[0064] As can be seen from Table 1, the addition of high-amino PA6T / 66 material can significantly improve the performance of the material, and the higher the proportion, the more excellent the performance. The surface of the reinforced recycled nylon material is not treated, and the performance decreases greatly, and the anti-aging performance of the material is also deteriorated. The addition of fly ash has a good effect on improving the warping of the reinforced nylon composite material, and can also improve the surface floating fiber.

[0065] The above is a further detailed description of the present application in combination with specific preferred embodiments, and the specific implementation of the present application should not be limited to these descriptions. For ordinary skilled persons in the art to which the present application belongs, without departing from the concept of the present application, a number of simple deductions or substitutions can be made, and all of them should be considered as falling within the protection scope of the present application.

Claims

1. A nylon composite material, characterized in that: It is prepared from the following raw materials in parts by weight: 50-67 parts of reinforced nylon recycled material, wherein the reinforced nylon recycled material is recycled gauge baffles and gauge blocks from high-speed railways or heavy-load lines, and the recycled gauge baffles and gauge blocks from high-speed railways or heavy-load lines are treated with a surface treatment solvent, wherein the surface treatment solvent is prepared from 20% to 30% aminosilicone, 60% to 80% ethanol, and 10% to 20% water; 10-25 parts of toughened nylon recycled material, wherein the toughened nylon recycled material is crushed material from baffle seats recycled from ordinary railway lines; 3 to 5 parts of auxiliary toughening recycled materials, which are recycled crushed materials of height adjustment pads in railway fastener systems; 3 to 8 parts of PA66 / 6T, wherein the terminal amino group content of the PA66 / 6T is 50 to 80 mmol / kg and the melting point is 255 to 270°C; 3 to 10 parts of industrial waste residue, wherein the industrial waste residue is fly ash; 0.3-2 parts of chain extender; 0.2 to 1 part of anti-aging agent.

2. The nylon composite material according to claim 1, characterized in that The glass fiber content of the reinforced nylon recycled material is 30-35%, and the melting point is 250-270°C.

3. The nylon composite material according to claim 1, characterized in that The elongation at break of the auxiliary toughened recycled material is greater than 50%.

4. The nylon composite material according to claim 1, characterized in that The melting point of the toughened nylon recycled material is greater than 210°C.

5. The nylon composite material according to claim 1, characterized in that The chain extender is selected from one of epoxy functional chain extender, oxazoline chain extender or carbonate functional chain extender; the anti-aging auxiliary agent is a mixture of antioxidant 1098, antioxidant 168 and heat-resistant special auxiliary agent H3336.

6. The method for preparing a nylon composite material according to any one of claims 1 to 5, wherein: The following steps are involved: S1. Recycle discarded gauge baffles and gauge blocks from the nylon fastener system of high-speed railways or heavy-load lines, remove oil and impurities, crush and dry them, and obtain reinforced nylon recycled materials after drying; S2, recycling discarded baffle seats from conventional railway lines, removing oil and impurities, crushing and drying them, and obtaining toughened nylon recycled materials; S3, recycling the discarded height adjustment pads in the railway fastener system, removing oil and impurities, crushing and drying them, and obtaining auxiliary toughening recycled materials; S4. Evenly mix the reinforced nylon recycled material, the toughened nylon recycled material, the auxiliary toughened recycled material, PA66 / 6T, industrial waste residue, the chain extender and the anti-aging agent according to their mass proportions, melt-extrude through a twin-screw extruder, and pelletize to obtain the nylon composite material.

7. The method for preparing a nylon composite material according to claim 6, wherein: Waste gauge baffles and gauge blocks are crushed to a particle size of ≤10mm, waste baffle seats are crushed to a particle size of less than ≤10mm, and waste height adjustment pads are crushed to a particle size of less than ≤10mm.

8. The method for preparing a nylon composite material according to claim 6, wherein: In step S2, the operating temperature of the twin-screw extruder is 245-280°C, and a ZME tooth-shaped mixing element is used in the screw assembly.

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