Wear-resistant casting nylon composite material and preparation method thereof

Abstract

The invention discloses a wear-resistant casting nylon composite material which is prepared from the following components in parts by weight: 92-98 parts of caprolactam, 2-8 parts of a wear-resistant agent g-C3N4, 0.2-3 parts of a catalyst and 0.2-3 parts of a cocatalyst, and the wear-resistant agent g-C3N4 is prepared from melamine through a deamidation reaction. The self-made wear-resistant agent g-C3N4 does not contain crystal water, does not inhibit polymerization, and does not affect the polymerization effect in a caprolactam ring-opening polymerization system; the wear-resistant agent g-C3N4 is of a planar two-dimensional lamellar structure similar to graphene, basic structural units infinitely extend to form a net structure, two-dimensional nanosheet layers are combined through Van der Waals force, and the bonding force between the layers can displace and slide along with wear of the material, so that the wear resistance of the material can be improved.

Description

Technical Field

[0001] The present invention relates to the field of polymer composites, and specifically to a wear-resistant cast nylon composite material and a preparation method thereof. Background Art

[0002] Cast nylon has good comprehensive properties and mechanical properties of high strength and high toughness. It has been widely used in the fields of machinery, steel, mining, etc. to replace steel. However, cast nylon products are usually used in parts such as axles, bearings, and bushings, and have high requirements for wear resistance. Especially after long-term use, with the photo-thermal aging of the material, the surface roughness increases, the friction factor increases, and the friction performance of the material deteriorates. Summary of the Invention

[0003] In view of this, the present invention provides a wear-resistant cast nylon composite material and a preparation method thereof to solve the problem of poor wear resistance of cast nylon proposed in the above background art. The present invention adds a self-made wear-resistant agent g-C3N4 to the cast PA6 system to improve the wear resistance of the PA6 composite material. The wear-resistant agent g-C3N4 itself is a nano material with a layered two-dimensional structure, which can be used as a solid lubricant filler to reduce the friction coefficient and improve the wear resistance of the composite material. During the use of the cast PA6 material modified by the wear-resistant agent g-C3N4, it is corroded by photo-thermal aging. Due to the presence of nano g-C3N4, which is a stable heat-resistant and light-resistant inorganic filler itself, it will not degrade due to photo-thermal aging, and has high strength. While the surrounding PA6 nylon will undergo partial degradation, resulting in uneven grooves on the surface of the aged material. When the surface of the material is rubbed, the chips of PA6 will flake off with the friction. The flaked chips will fill the grooves of the aged product, thus obtaining a flat surface and re-obtaining a modified PA6 material with better friction performance.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] On the one hand, the present invention discloses a wear-resistant cast nylon composite material, which is prepared from the following components according to weight parts:

[0006]

[0007]

[0008] Among them, the wear-resistant agent g-C3N4 is prepared by deamidation reaction of melamine.

[0009] As a further scheme of the present invention: the caprolactam is ε-caprolactam, and its purity is above 99%.

[0010] As a further solution of the present invention: the catalyst is sodium hydroxide, and the addition amount of the sodium hydroxide is 0.2-3% of the weight parts of caprolactam.

[0011] As a further solution of the present invention: the co-catalyst is TDI, and the addition amount of the TDI is 0.2-3% of the weight parts of caprolactam.

[0012] As a further solution of the present invention: the preparation method of the wear-resistant agent g-C3N4 includes the following steps:

[0013] Melamine is heated in a muffle furnace at a heating rate of 5-10 °C / min to 450-550 °C and kept for 4-6 hours. After the deamidation reaction is completed, the wear-resistant agent g-C3N4 is obtained.

[0014] On the other hand, the present invention discloses a preparation method of a wear-resistant cast nylon composite material as described in any one of the above, including the following steps:

[0015] Caprolactam is put into a container and heated to melt, and then evacuated. The temperature in the container is controlled at 120-160 °C;

[0016] Wait until the bubbles in the container completely disappear. Restore the normal pressure in the container, add the wear-resistant agent g-C3N4 and the catalyst, continue to evacuate, and control the reaction temperature at 120-160 °C;

[0017] Wait until the bubbles in the container completely disappear, restore the normal pressure in the container again, add the co-catalyst, quickly stir evenly, and then introduce it into a mold with a preheating temperature of 140-170 °C. After heat preservation for 0.5-3 hours, take it out and cool naturally to obtain the wear-resistant cast nylon composite material.

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] The self-made wear-resistant agent g-C3N4 of the present invention has no crystal water and does not inhibit polymerization itself, and does not affect the polymerization effect in the ring-opening polymerization system of caprolactam; the wear-resistant agent g-C3N4 is a planar two-dimensional sheet structure similar to graphene, and the basic structural units extend infinitely to form a network structure. The two-dimensional nanosheets are combined by van der Waals forces, and the binding force between the layers can shift and slide with the wear of the material, thereby improving the wear resistance of the material.

[0020] In the ring-opening polymerization system of the present invention, the viscosity of the molten caprolactam monomer is very low, which is beneficial to the uniform dispersion of g-C3N4; in the PA6 composite material after casting polymerization, due to the dispersion of the wear-resistant agent g-C3N4 and the high thermal stability of g-C3N4 itself, it can absorb blue-violet light with a wavelength less than 475 in the solar spectrum and has certain weather resistance. As a result, uneven gully-like surfaces will be generated on the surface of the product after xenon lamp aging. When the gully-like material surface is worn, debris will fall into the gully grooves and fill the grooves, thus forming a flat surface similar to that of the unaged sample and restoring a better friction-resistant material. Detailed Embodiments

[0021] To facilitate the understanding of the present invention, the present invention will be described more comprehensively below in conjunction with specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0023] The specific information of the raw materials used in the following examples and comparative examples is as follows:

[0024] ε-Caprolactam, manufactured by Henan Shenma, with the product number of Caprolactam-SM;

[0025] Melamine, manufactured by Huixi Chemical Industry, with the product number of Melamine;

[0026] Sodium hydroxide, manufactured by Linyi Haixing Chemical Industry, with the product number of Sodium hydroxide;

[0027] TDI (toluene diisocyanate), manufactured by Wanhua Chemical, with the product number of TDI;

[0028] All materials are commercially available conventional and commonly used products.

[0029] It can be understood that the above raw material reagents are only examples of some specific embodiments of the present invention to make the technical solution of the present invention clearer, and do not represent that the present invention can only use the above reagents. The specific scope is subject to the scope in the claims. In addition, the "parts" mentioned in the examples and comparative examples refer to parts by weight unless otherwise specified.

[0030] Any range described in the present invention includes the end values and any numerical value between the end values, as well as any sub-range constituted by any numerical value between the end values or the end values.

[0031] Example 1

[0032] Put 95 parts of ε-caprolactam into a three-necked flask, heat it up. When the monomers in the flask melt, connect the vacuum system. The temperature in the flask is 140 °C. Remove the water and low-boiling impurities in the flask under vacuum until the bubbles in the flask completely disappear. Restore the vacuum degree of the system to normal pressure, add 5 parts of wear-resistant agent g-C3N4, add 0.95 part of sodium hydroxide, continue to evacuate, and control the reaction temperature at 130 °C. When the bubbles in the flask completely disappear, disconnect the vacuum system, restore the vacuum degree in the three-necked flask to normal pressure, add 0.475 part of TDI into the three-necked flask, quickly stir evenly, and then introduce it into a mold preheated to 160 °C. The mold is taken out after being kept warm in an oven at 150 °C for 2 hours and cooled naturally to obtain the wear-resistant cast nylon composite material;

[0033] The wear-resistant agent g-C3N4 is prepared by the following method: Put melamine in a muffle furnace and heat it to 520 °C at a heating rate of 6 °C / min, keep it for 5 hours, and the deamidation reaction is completed to obtain the wear-resistant agent g-C3N4.

[0034] Example 2

[0035] Put 96 parts of ε-caprolactam into a three-necked flask, heat it up. When the monomers in the flask melt, connect the vacuum system. The temperature in the flask is 150 °C. Remove the water and low-boiling impurities in the flask under vacuum and wait until the bubbles in the flask completely disappear. Restore the vacuum degree of the system to normal pressure, add 4 parts of wear-resistant agent g-C3N4, add 0.48 part of sodium hydroxide, continue to evacuate, and control the reaction temperature at 150 °C. When the bubbles in the flask completely disappear, disconnect the vacuum system, restore the vacuum degree in the three-necked flask to normal pressure, add 0.96 part of TDI into the three-necked flask, quickly stir evenly, and then introduce it into a mold preheated to 150 °C. The mold is taken out after being kept warm in an oven at 160 °C for 1.5 hours and cooled naturally to obtain the wear-resistant cast nylon composite material;

[0036] The wear-resistant agent g-C3N4 is prepared by the following method: Put melamine in a muffle furnace and heat it to 500 °C at a heating rate of 8 °C / min, keep it for 5 hours, and the deamidation reaction is completed to obtain the wear-resistant agent g-C3N4.

[0037] Example 3

[0038] Put 93 parts of ε-caprolactam into a three-necked flask, heat it up. When the monomers in the flask melt, connect the vacuum system. The temperature in the flask is 140 °C. Remove the moisture and low-boiling impurities in the flask under vacuum and wait until the bubbles in the flask completely disappear. Restore the vacuum degree of the system to normal pressure, add 7 parts of wear-resistant agent g-C3N4, add 1.86 parts of sodium hydroxide, continue to evacuate, and control the reaction temperature at 145 °C. When the bubbles in the flask completely disappear, disconnect the vacuum system, restore the vacuum degree in the three-necked flask to normal pressure, add 1.86 parts of TDI to the three-necked flask, quickly stir evenly, then pour it into a mold preheated to 160 °C. The mold is taken out after being kept warm in an oven at 150 °C for 2.5 hours and cooled naturally to obtain the wear-resistant cast nylon composite material;

[0039] The wear-resistant agent g-C3N4 is prepared by the following method: Melamine is heated to 480 °C in a muffle furnace at a heating rate of 8 °C / min and kept for 4 hours. The deamidation reaction is completed to obtain the wear-resistant agent g-C3N4.

[0040] Example 4

[0041] Put 98 parts of ε-caprolactam into a three-necked flask, heat it up. When the monomers in the flask melt, connect the vacuum system. The temperature in the flask is 120 °C. Remove the moisture and low-boiling impurities in the flask under vacuum and wait until the bubbles in the flask completely disappear. Restore the vacuum degree of the system to normal pressure, add 2 parts of wear-resistant agent g-C3N4, add 0.196 parts of sodium hydroxide, continue to evacuate, and control the reaction temperature at 120 °C. When the bubbles in the flask completely disappear, disconnect the vacuum system, restore the vacuum degree in the three-necked flask to normal pressure, add 0.196 parts of TDI to the three-necked flask, quickly stir evenly, then pour it into a mold preheated to 140 °C. The mold is taken out after being kept warm in an oven at 140 °C for 0.5 hours and cooled naturally to obtain the wear-resistant cast nylon composite material;

[0042] The wear-resistant agent g-C3N4 is prepared by the following method: Melamine is heated to 450 °C in a muffle furnace at a heating rate of 5 °C / min and kept for 4 hours. The deamidation reaction is completed to obtain the wear-resistant agent g-C3N4.

[0043] Example 5

[0044] Put 92 parts by mass of ε-caprolactam into a three-necked flask, heat it up. When the monomers in the flask melt, connect the vacuum system. The temperature in the flask is 160 °C. Remove the moisture and low-boiling impurities in the flask under vacuum, and wait until the bubbles in the flask completely disappear. Restore the vacuum degree of the system to normal pressure, add 8 parts by mass of wear-resistant agent g-C3N4, add sodium hydroxide (the addition amount of sodium hydroxide is 3% of the mass concentration of caprolactam), continue to evacuate, and control the reaction temperature at 160 °C. When the bubbles in the flask completely disappear, disconnect the vacuum system, restore the vacuum degree in the three-necked flask to normal pressure, add TDI (the addition amount of TDI is 3% of the mass concentration of caprolactam) into the three-necked flask, quickly stir evenly, and then introduce it into a mold preheated to 170 °C. The mold is kept warm in an oven at 160 °C for 3 hours and then taken out and cooled naturally to obtain the wear-resistant cast nylon composite material;

[0045] The wear-resistant agent g-C3N4 is prepared by the following method: Heat melamine in a muffle furnace at a heating rate of 10 °C / min to 550 °C and keep it for 6 hours. The deamidation reaction is completed to obtain the wear-resistant agent g-C3N4.

[0046] Comparative Example 1

[0047] Put 100 parts of ε-caprolactam into a three-necked flask, heat it up. When the monomers in the flask melt, connect the vacuum system. The temperature in the flask is 140 °C. Remove the moisture and low-boiling impurities in the flask under vacuum, and wait until the bubbles in the flask completely disappear. Restore the vacuum degree of the system to normal pressure, add 1 part of sodium hydroxide, continue to evacuate, and control the reaction temperature at 130 °C. When the bubbles in the flask completely disappear, disconnect the vacuum system, restore the vacuum degree in the three-necked flask to normal pressure, add 0.5 part of TDI into the three-necked flask, quickly stir evenly, and then introduce it into a mold preheated to 160 °C. The mold is kept warm in an oven at 150 °C for 2 hours and then taken out and cooled naturally to obtain the modified PA6 composite material.

[0048] Comparative Example 2

[0049] Put 95 parts of ε-caprolactam into a three-necked flask, heat it up. When the monomers in the flask melt, connect the vacuum system. The temperature in the flask is 140 °C. Remove the moisture and low-boiling impurities in the flask under vacuum, and wait until the bubbles in the flask completely disappear. Restore the vacuum degree of the system to normal pressure, add 5 parts of molybdenum disulfide material, add 0.95 part of sodium hydroxide, continue to evacuate, and control the reaction temperature at 130 °C. When the bubbles in the flask completely disappear, disconnect the vacuum system, restore the vacuum degree in the three-necked flask to normal pressure, add 0.475 part of TDI into the three-necked flask, quickly stir evenly, and then introduce it into a mold preheated to 160 °C. The mold is kept warm in an oven at 150 °C for 2 hours and then taken out and cooled naturally to obtain the modified PA6 composite material.

[0050] The wear-resistant cast nylon composites obtained in Examples 1-5 and the modified PA6 composites obtained in Comparative Examples 1-2 were made into samples with a thickness of 20 mm and a testable area diameter Φ > 20 mm on the upper and lower surfaces for friction and wear performance testing. The friction coefficient was tested with reference to GB / T 3960-1983 on an MM-W1 type vertical universal friction and wear testing machine.

[0051] The aging conditions are specifically as follows:

[0052] Thermal aging conditions: Aging at 120 °C for 600 hours; Photoaging conditions: According to the NES M0135 standard, irradiance 53 W / m2, total irradiation dose 130 MJ / m2, total test time 681 hours. After thermal aging and photoaging in sequence, the samples were tested for friction again.

[0053] Table 1

[0054]

[0055] It can be seen from the test results in Table 1 that the wear-resistant cast nylon composites prepared by the method of the present invention have a lower friction coefficient. Especially after aging, they can still maintain a lower friction coefficient and have good wear resistance. The prepared parts are more suitable for long-term applications, can extend the service life, and expand the use under outdoor and harsh environmental conditions.

[0056] Although this specification is described according to the implementation manners, not every implementation manner only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other implementation manners that can be understood by those skilled in the art.

[0057] Therefore, the above description is only the preferred embodiment of the present application and is not used to limit the scope of implementation of the present application; that is, all equivalent transformations made according to the scope of the claims of the present application are within the protection scope of the claims of the present application.

Claims

1. A wear-resistant cast nylon composite material, characterized in that, it is prepared from the following components by weight: Among them, the wear-resistant agent g-C3N4 is prepared from melamine through a deamidation reaction.

2. The wear-resistant cast nylon composite material according to claim 1, characterized in that, the caprolactam is ε-caprolactam, and its purity is above 99%.

3. The wear-resistant cast nylon composite material according to claim 1, characterized in that, the catalyst is sodium hydroxide, and the addition amount of the sodium hydroxide is 0.2-3% of the weight of caprolactam.

4. The wear-resistant cast nylon composite material according to claim 1, characterized in that, the co-catalyst is TDI, and the addition amount of the TDI is 0.2-3% of the weight of caprolactam.

5. The wear-resistant cast nylon composite material according to claim 1, characterized in that, the preparation method of the wear-resistant agent g-C3N4 includes the following steps: Heat melamine in a muffle furnace at a heating rate of 5-10 °C / min to 450-550 °C, and keep it for 4-6 hours. After the deamidation reaction is completed, the wear-resistant agent g-C3N4 is obtained.

6. The preparation method of a wear-resistant cast nylon composite material according to any one of claims 1-5, characterized in that, includes the following steps: Put caprolactam into a container and heat it to melt, then evacuate, and control the temperature in the container at 120-160 °C; Wait until the bubbles in the container completely disappear. Restore the normal pressure in the container, add the wear-resistant agent g-C3N4 and the catalyst, continue to evacuate, and control the reaction temperature at 120-160 °C; Wait until the bubbles in the container completely disappear, restore the normal pressure in the container again, add the co-catalyst, quickly stir evenly, then introduce it into a mold with a preheating temperature of 140-170 °C, keep it warm for 0.5-3 hours and then take it out, and cool it naturally to obtain the wear-resistant cast nylon composite material.

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