Nylon composite material and preparation method thereof

Abstract

The invention discloses a nylon composite material and a preparation method thereof, the nylon composite material is prepared from 50-67 parts of a reinforced nylon reclaimed material, 10-25 parts of a toughened nylon reclaimed material, 3-5 parts of an auxiliary toughened reclaimed material, 3-8 parts of high-end amino PA66 / 6T, and 3-10 parts of industrial waste residue, and the industrial waste residue is prepared from fly ash, 0.3-2 parts of a chain extender and 0.2-1 part of an anti-aging agent. Wherein the reinforced nylon regenerated material is a high-speed rail or heavy-load line recycled gauge apron and gauge block crushed material, the toughened nylon regenerated material is a common iron line recycled baffle seat crushed material, and the auxiliary toughened regenerated material is a railway fastener system recycled heightening base plate crushed material. According to the invention, the nylon fastener recycled material in a railway system is used, the performance of each fastener material is fully utilized, and the reinforced nylon composite material which is environment-friendly, high in performance, simple to process and obvious in price advantage is prepared.

Description

Technical Field

[0001] The invention belongs to the technical field of composite materials, and in particular relates to a nylon composite material and a preparation method thereof. Background Art

[0002] my country's rail transit industry is developing rapidly, and various railway fastener products are widely used. The railway fastener system is a part used to connect the rails and sleepers (or other types of rail foundations) on the track, also known as the intermediate connecting parts. Its main function is to fix the rails on the sleepers, maintain the gauge and prevent the longitudinal and lateral movement of the rails relative to the sleepers. The railway fastener system is crucial to ensure the safe and stable operation of the railway, and it directly affects the safety and comfort of the railway. In these fastener systems, gauge baffles, gauge blocks, height adjustment pads and other components are made of thermoplastic polymer materials, including reinforced nylon, toughened nylon, polyethylene, etc. As the application time of fasteners increases, various diseases will occur as a whole, affecting driving safety, and they need to be replaced regularly. After more than ten years of operation, it is estimated that tens of millions of fasteners will be replaced every year in my country's high-speed railway system, and a large number of plastic parts will be replaced. If not properly handled, it will seriously affect environmental safety and do not meet the inherent requirements of green and sustainable development of my country's high-speed railways.

[0003] The replaced products involve many types of materials. Currently, many manufacturers only process a certain type of product material separately. After crushing, they are compounded with new raw materials and modified. Most of them are used as recycled materials. The overall cost of the products is high and the centralized utilization rate is not high.

[0004] Railway fastener nylon products have their own particularities, and my country's fastener non-metallic parts and materials have clear performance requirements, which ensures the consistency of the initial performance of various materials. The performance degradation of the replaced products is mainly caused by molecular chain breakage caused by mechanical fatigue damage, water absorption and plasticization, and the peeling of glass fiber and matrix resin. In addition, all recycled raw materials are aged by light and oxygen, and the polar groups increase. After re-application, the water absorption will be further improved, which accelerates the performance degradation of the recycled products. How to reuse the above-mentioned abandoned parts with performance degradation has become a current problem. Summary of the invention

[0005] In order to overcome the problems in the prior art, the present invention provides a nylon composite material and a preparation method thereof, combines the performance changes of the replaced fastener crushed materials, makes full use of the performance of each fastener material, explores a new green way to deal with railway waste non-metallic parts, and prepares an environmentally friendly, high-performance, simple to process, and price-competitive reinforced nylon composite material.

[0006] In order to solve the above technical problems, the technical solution proposed by the present invention is: The present invention provides a nylon composite material, which 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 the broken material of gauge baffles and gauge blocks recycled from high-speed railways or heavy-load lines; 10 to 25 parts of toughened nylon recycled material, wherein the toughened nylon recycled material is the broken material of the baffle seat recycled from ordinary railway lines; 3-5 parts of auxiliary toughening recycled materials, which are recycled height adjustment pad crushing materials of railway fastener system; PA66 / 6T 3-8 parts; 3 to 10 parts of industrial waste residue, wherein the industrial waste residue is fly ash; Chain extender 0.3-2 parts; Anti-aging agent 0.2 to 1 part.

[0007] The recycled gauge baffle and gauge block crushed materials, recycled baffle seat crushed materials and recycled height adjustment pad crushed materials used in the present invention have particular performance degradation caused by the product use conditions and environment, mainly due to the molecular chain breakage caused by mechanical fatigue damage, water absorption and plasticization, and the performance degradation caused by the peeling of glass fiber and matrix resin. At the same time, all recycled raw materials are photo-oxidation aged, and the polar groups increase. After re-application, the water absorption will be further improved, which accelerates the performance degradation of the recycled product. Therefore, high-temperature nylon PA66 / 6T is also added in this application to improve the interface bonding force between glass fiber, filler and matrix resin, and at the same time, it can reduce the subsequent water absorption rate of the recycled product and maintain the high performance of the product; it is used in combination with a chain extender, which has an auxiliary effect on improving the viscosity of the material. At the same time, the melting point of PA66 / 6T is similar to that of the matrix, and does not affect the processing technology.

[0008] As an optional embodiment, in the nylon composite material provided by the present invention, the glass fiber content of the reinforced nylon recycled material is 30-35%, and the melting point is 250-270°C.

[0009] Controlling the glass fiber content of reinforced nylon recycled material to 30-35% and the melting point to 250-270°C can ensure the purity of the recycled material and the performance of the subsequently prepared composite nylon material is the best.

[0010] As an optional embodiment, in the nylon composite material provided by the present invention, the melting point of the toughened nylon recycled material is greater than 210°C.

[0011] Controlling the melting point of toughened nylon recycled material to be greater than 210°C can ensure the purity of the recycled material and the performance of the subsequently prepared composite nylon material is the best.

[0012] As an optional embodiment, in the nylon composite material provided by the present invention, the elongation at break of the auxiliary toughening recycled material is greater than 50%.

[0013] The elongation at break of the auxiliary toughening recycled material is controlled to be greater than 50% to ensure that it has the best effect as an auxiliary toughening agent.

[0014] As an optional implementation, in the nylon composite material provided by the present invention, the particle size of the fly ash is 300-400 meshes.

[0015] As an optional implementation, in the nylon composite material provided by the present invention, the terminal amino group content of the PA66 / 6T is 50-80 mmol / Kg, and the melting point is 255-270°C.

[0016] In the present invention, PA66 / 6T is a copolymer material with an adjustable and controllable melting point. When the melting point is controlled within this range, it is close to that of PA66, does not affect the processing technology, and has relatively stable performance. In addition, the high terminal amino group helps to improve the compatibility of glass fiber and resin, making the product performance more excellent.

[0017] As an optional embodiment, in the nylon composite material provided by the present invention, the high-speed railway or heavy-load line recycled gauge baffle and gauge block crushed material are treated with a surface treatment solvent, and the surface treatment solvent is composed of 20% to 30% aminosilicone, 60% to 80% ethanol, and 10 to 20% water.

[0018] In order to solve the problem of performance attenuation of recycled raw material products in the present invention, the discarded gauge baffles and gauge blocks in the nylon fastener system of the recycled high-speed railway or heavy-load line are treated with a surface treatment solvent, and the broken gauge baffles and gauge blocks are regarded as fillers. After the crushing, the glass fiber is exposed, and after the surface is wetted, it helps to improve the interface performance between the glass fiber and the matrix resin. The main function of the surface treatment solvent in the present invention is coupling, which is conventionally used to treat fillers, but in this application, it is used to treat the reinforced crushed material, which can improve the compatibility of the glass fiber and the resin and reduce the performance degradation caused by the peeling of the two.

[0019] As an optional embodiment, in the nylon composite material provided by the present invention, the chain extender is selected from one of an epoxy functional chain extender, an oxazoline chain extender or a carbonate functional chain extender.

[0020] As an optional implementation, in the nylon composite material provided by the present invention, the anti-aging additive is a mixture of antioxidant 1098, antioxidant 168 and special heat-resistant additive H3336.

[0021] As an optional embodiment, in the nylon composite material provided by the present invention, the volume ratio of the mixture of antioxidant 1098, antioxidant 168 and special heat-resistant additive H3336 is 1:1:1.

[0022] Based on the same technical concept, the present invention also provides a method for preparing the above-mentioned nylon composite material, comprising the following steps: S1. Recycle the discarded gauge baffles and gauge blocks in 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.

[0023] S2: Recycle discarded baffle seats from ordinary railway lines, remove oil and impurities, crush and dry them, and obtain toughened nylon recycled materials.

[0024] S3. Recycle the discarded height adjustment pads in the railway fastener system, remove oil and impurities, crush and dry them, and obtain auxiliary toughening recycled materials.

[0025] S4. Evenly mix the reinforced nylon recycled material, toughened nylon recycled material, auxiliary toughened recycled material, PA66 / 6T, industrial waste residue, chain extender and anti-aging agent according to their mass proportions, melt-extrude and pelletize through a twin-screw extruder to obtain the nylon composite material.

[0026] As an optional embodiment, in the preparation method provided by the present invention, the discarded gauge baffles and gauge blocks are crushed to a particle size of ≤10mm, the discarded baffle seats are crushed to a particle size of less than ≤10mm, and the discarded height adjustment pads are crushed to a particle size of less than ≤10mm.

[0027] As an optional embodiment, in the preparation method provided by the present invention, in step S2, the operating temperature of the twin-screw extruder is 245-280° C., and a ZME toothed mixing element is used in the screw assembly.

[0028] Compared with the prior art, the present invention has the following beneficial effects: (1) The nylon composite material of the present invention uses resin raw materials from waste parts replaced by railway fasteners, and uses mineral fillers from industrial waste slag, which is green and environmentally friendly and has obvious cost advantages.

[0029] (2) The raw materials used for railway non-metallic fasteners are all subject to unified iron standards, with uniform initial performance and basically similar performance changes of discarded products, ensuring the stability of recycled materials. At the same time, the maintenance and replacement products of each line are relatively concentrated and large in quantity, which is easy to recycle and has a reliable source.

[0030] (3) By controlling the key properties of various recycled materials, combining modification technology, and mixing them in different proportions, the prepared nylon composite materials have excellent mechanical properties, and the injection molded products have good appearance and low warpage deformation.

[0031] (4) The present invention performs surface treatment on the reinforced nylon recycled material and adds high-end amino content PA66 / 6T. Under the action of chain extender, it can effectively overcome the recycling disadvantage of fastener nylon due to performance attenuation and improve the comprehensive performance of nylon composite materials and products. DETAILED DESCRIPTION

[0032] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and meticulously below in combination with the specification and preferred embodiments, but the protection scope of the present invention is not limited to the following specific embodiments.

[0033] Unless otherwise defined, all professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0034] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0035] Example 1 The preparation of nylon composite material comprises the following steps: (1) Recycle nylon fasteners from high-speed railways or heavy-load lines, including discarded gauge baffles and gauge blocks, to remove oil and impurities, crush them into pieces with a particle size of less than 10 mm, then dry and mix them evenly, take the mixed materials and directly inject the samples, the glass fiber content of the test samples is within 30-35%, the melting point is 250-270°C, then slowly add a surface treatment solvent composed of 30% aminosilicone, 60% ethanol and 10% water into the qualified crushed materials in the high-speed mixer at a ratio of 2% and stir for 5-10 minutes, and finally dry them at 120°C for 2 hours to obtain the reinforced nylon recycled materials for standby use.

[0036] (2) Remove oil and impurities from the waste baffle seat products recycled from ordinary railway lines, crush them into pieces with a particle size of less than 1 cm, and then dry and mix them evenly. Take the mixed material and directly inject the sample. The melting point of the test sample is greater than 210°C, and the toughened nylon recycled material is obtained for standby use.

[0037] (3) Remove oil and impurities from the discarded height adjustment pads of different thicknesses from the railway fastener system, crush them into pieces with a particle size of less than 1 cm, and then dry and mix them evenly. Take the mixed materials and directly inject the samples. The elongation at break is above 50%, and the auxiliary toughened recycled materials are obtained for standby use.

[0038] (4) Take 67 parts of the above-mentioned reinforced nylon recycled material, 13.4 parts of toughened nylon recycled material, 7 parts of PA66 / 6T with an end amino content of 50-80 mmol / Kg and a melting point of 255-270°C, 3 parts of auxiliary toughening recycled material, 8 parts of fly ash, 1 part of Brueggemann M1251 chain extender, and 0.6 parts of anti-aging additive (1098:168:H3336=1:1:1), mix them evenly, melt extrude them through a twin-screw extruder at 245-280°C, cut them into pellets, and use a ZME toothed mixing element in the screw assembly to obtain a nylon composite material.

[0039] Example 2 67 parts of reinforced nylon recycled material prepared in Example 1, 17.4 parts of toughened nylon recycled material, 3 parts of PA66 / 6T with a terminal amino content of 50-80 mmol / Kg and a melting point of 255-270°C, 3 parts of auxiliary toughening recycled material, 8 parts of fly ash, 1 part of Brueggemann M1251 chain extender, and 0.6 parts of anti-aging additive (1098:168:H3336=1:1:1) were mixed uniformly, melt-extruded and pelletized at 260-280°C through a twin-screw extruder, and a ZME toothed mixing element was used in the screw assembly to obtain a nylon composite material.

[0040] Example 3 60.4 parts of the reinforced nylon recycled material prepared in Example 1, 20 parts of the toughened nylon recycled material, 7 parts of PA66 / 6T with an end amino content of 50-80 mmol / Kg and a melting point of 255-270°C, 3 parts of auxiliary toughening recycled material, 8 parts of fly ash, 1 part of Brueggemann M1251 chain extender, and 0.6 parts of anti-aging additive (1098:168:H3336=1:1:1) were mixed uniformly, melt-extruded and pelletized at 245-280°C through a twin-screw extruder, and a ZME toothed mixing element was used in the screw assembly to obtain a nylon composite material.

[0041] Example 4 67.4 parts of reinforced nylon recycled material (the difference from Example 1 is that it has not been treated with a surface treatment solvent containing 30% aminosilicone, 60% ethanol and 10% water), 13 parts of toughened nylon recycled material prepared in Example 1, 3 parts of auxiliary toughening recycled material, 7 parts of PA66 / 6T with an end amino content of 50-80 mmol / Kg and a melting point of 255-270°C, 8 parts of fly ash, 1 part of Brueggemann M1251 chain extender, and 0.6 parts of anti-aging additive (1098:168:H3336=1:1:1) were mixed uniformly, melt-extruded and pelletized at 245-280°C through a twin-screw extruder, and a ZME toothed mixing element was used in the screw assembly to obtain a nylon composite material.

[0042] Comparative Example 1 70 parts of the reinforced nylon recycled material and 30 parts of the toughened nylon recycled material prepared in Example 1 were mixed evenly, melt-extruded and pelletized at 245-280° C. through a twin-screw extruder, and a ZME toothed mixing element was used in the screw assembly to obtain a nylon composite material.

[0043] Comparative Example 2 67 parts of reinforced nylon recycled material prepared in Example 1, 20.4 parts of toughened nylon recycled material, 3 parts of auxiliary toughening recycled material, 8 parts of fly ash, 1 part of Brueggemann M1251 chain extender, and 0.6 parts of anti-aging additive (1098:168:H3336=1:1:1) were mixed uniformly, melt-extruded and pelletized at 245-280° C. through a twin-screw extruder, and a ZME toothed mixing element was used in the screw assembly to obtain a nylon composite material.

[0044] The nylon composite materials prepared in the examples and comparative examples were tested for performance, and the test results are shown in Table 1 below.

[0045] Table 1: Performance test of the products of the embodiments and comparative examples

[0046] It can be seen from the embodiments and comparative examples in Table 1 that the addition of high amino PA6T / 66 material can significantly improve the material performance, and the higher the proportion, the better the performance; the surface of the reinforced recycled nylon material is not treated, the performance decreases significantly, and the material's anti-aging performance also deteriorates; 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.

[0047] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the scope of protection of the present invention.

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 the broken material of gauge baffles and gauge blocks recycled from high-speed railways or heavy-load lines; 10 to 25 parts of toughened nylon recycled material, wherein the toughened nylon recycled material is the broken material of the baffle seat recycled from ordinary railway lines; 3-5 parts of auxiliary toughening recycled materials, which are recycled height adjustment pad crushing materials of railway fastener system; PA66 / 6T 3-8 parts; 3 to 10 parts of industrial waste residue, wherein the industrial waste residue is fly ash; Chain extender 0.3-2 parts; Anti-aging agent 0.2 to 1 part.

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 terminal amino group content of the PA66 / 6T is 50-80 mmol / Kg, and the melting point is 255-270°C.

4. 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%.

5. 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.

6. The nylon composite material according to claim 1, characterized in that: The high-speed rail or heavy-load line recycled gauge baffle and gauge block crushed materials are treated with a surface treatment solvent, and the surface treatment solvent is prepared from 20% to 30% aminosiloxane, 60% to 80% ethanol, and 10 to 20% water.

7. 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.

8. The method for preparing a nylon composite material according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1. Recycle the discarded gauge baffles and gauge blocks in 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 the discarded baffle seats of ordinary railway lines, removing oil stains 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, toughened nylon recycled material, auxiliary toughened recycled material, PA66 / 6T, industrial waste residue, chain extender and anti-aging agent according to their mass proportions, melt-extrude and pelletize through a twin-screw extruder to obtain the nylon composite material.

9. The method for preparing the nylon composite material according to claim 8, characterized in that: The discarded gauge baffles and gauge blocks are crushed to a particle size of ≤10mm, the discarded baffle seats are crushed to a particle size of less than ≤10mm, and the discarded height adjustment pads are crushed to a particle size of less than ≤10mm.

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

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