A modified cast nylon wheel and its preparation process

Abstract

The invention discloses a modified cast nylon wheel and a preparation process thereof. The raw materials of the modified cast nylon wheel include: caprolactam monomer, a first ionic liquid, modified montmorillonite, a catalyst and a co-catalyst. The modified montmorillonite includes a montmorillonite body and a second ionic liquid. The interface bonding strength between the montmorillonite and the nylon matrix is improved, the load transfer efficiency is improved, the creep deformation rate is significantly delayed, and the modified montmorillonite extends the water molecule penetration path. The montmorillonite treated with the second ionic liquid forms a nano-level layered structure, which is uniformly dispersed in the nylon matrix, constructing a dense "maze effect" and reducing hygroscopicity. The ionic liquid promotes the formation of chemical bonds between molecular chains during polymerization, constructing a three-dimensional network structure, and improving creep resistance. The defects of dimensional expansion caused by excessive hygroscopicity and poor creep resistance during use of port crane nylon wheels in the prior art are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of new materials, in particular to a modified cast nylon wheel and a preparation process thereof. Background Art

[0002] Port cranes are core equipment for operations in ports, docks, and other waterways, specifically used for cargo loading and unloading, ship berthing, and yard management. Nylon pulleys are used to guide and support the wire ropes, replacing traditional steel pulleys to reduce wire rope wear and extend their service life.

[0003] When the nylon wheels of port cranes are continuously overloaded, they will creep and expand radially, which will increase the gap with the rails or wire ropes and cause vibration or abnormal wear. Nylon material itself has good hygroscopicity. After absorbing water, the nylon wheel will further expand in size, resulting in an increase in the gap with the rails or wire ropes, and an increased risk of vibration and eccentric wear.

[0004] Therefore, it is necessary to improve the modified cast nylon wheel in the prior art to solve the above problems. Summary of the Invention

[0005] The present invention overcomes the shortcomings of the prior art and provides a modified cast nylon wheel and a preparation process thereof, aiming to solve the defects of the prior art nylon wheels for port cranes, such as dimensional expansion caused by excessive hygroscopicity and poor creep resistance during use.

[0006] To achieve the above object, the technical solution adopted by the present invention is: a modified cast nylon wheel, wherein the raw materials of the modified cast nylon wheel include, by weight, 80-120 parts of caprolactam monomer, 8-12 parts of a first ionic liquid, 2-4 parts of modified montmorillonite, 0.1-1 parts of a catalyst, and 0.1-1 parts of a co-catalyst;

[0007] The first ionic liquid is a pyridine ionic liquid, the modified montmorillonite includes a montmorillonite body and a second ionic liquid, the montmorillonite body is one of sodium-based montmorillonite and calcium-based montmorillonite, and the second ionic liquid is an imidazole ionic liquid.

[0008] In a preferred embodiment of the present invention, the mass ratio of the raw materials of the montmorillonite body and the second ionic liquid in the modified montmorillonite is 80-95:5-20.

[0009] In a preferred embodiment of the present invention, the structural formula of the first ionic liquid is:

[0010]

[0011] Wherein R1 and R2 are respectively one of methyl, ethyl, butyl and acetoxy, X -It is one of the chloride ion, bromide ion and boron tetrafluoride root.

[0012] In a preferred embodiment of the present invention, the structural formula of the second ionic liquid is:

[0013]

[0014] Where R is C n H 2n SO3H (n is an integer, 1≤n≤4), Y - It is one of chloride ion, bromide ion, iodide ion and acetate ion.

[0015] In a preferred embodiment of the present invention, the catalyst is one of sodium hydroxide, potassium hydroxide and sodium carbonate, and the co-catalyst is isocyanate.

[0016] To achieve the above-mentioned object, the second technical solution adopted by the present invention is: a preparation process of a modified cast nylon wheel, comprising the following steps:

[0017] S1: Mixing the montmorillonite and the second ionic liquid in water, stirring at 60-70°C for 3-4 hours, separating, drying, and grinding to obtain modified montmorillonite;

[0018] S2: Place caprolactam monomer and the modified montmorillonite in S1 into a reactor at a temperature of 70-85° C. and stir for 0.5-2 h;

[0019] S3: Add the catalyst and co-catalyst to the reactor, control the pressure in the reactor to 0.05-0.1 MPa, vacuum dehydrate for 15-30 minutes, add the first ionic liquid, control the temperature to 135-150°C, and continue the reaction for 0.5-2 hours;

[0020] S4: placing the material in the reactor into a nylon wheel mold and centrifuging it, taking it out and cooling and solidifying it to obtain a modified cast nylon wheel.

[0021] In a preferred embodiment of the present invention, the mass ratio of the total mass of the montmorillonite body and the second ionic liquid to water is 1:5-10.

[0022] In a preferred embodiment of the present invention, the grinding process parameters in S1 are: grinding speed of 300-500 r / min, and grinding time of 20-40 min.

[0023] In a preferred embodiment of the present invention, the centrifugal speed in S4 is 200-400 rpm.

[0024] In a preferred embodiment of the present invention, the centrifugation time in S4 is 2-4 minutes.

[0025] The present invention solves the defects existing in the background technology and has the following beneficial effects:

[0026] (1) The present invention provides a modified cast nylon wheel. The raw materials of the modified cast nylon wheel include: caprolactam monomer, a first ionic liquid, modified montmorillonite, a catalyst and a co-catalyst. The modified montmorillonite includes a montmorillonite body and a second ionic liquid. The interface bonding strength between the montmorillonite and the nylon matrix is improved, the load transfer efficiency is improved, the creep deformation rate is significantly slowed, and the modified montmorillonite extends the water molecule penetration path. Compared with the nylon wheel in the prior art, the montmorillonite treated with the second ionic liquid forms a nano-layered structure, is uniformly dispersed in the nylon matrix, constructs a dense "maze effect", reduces hygroscopicity, and the ionic liquid promotes the formation of chemical bonds between molecular chains during polymerization, constructs a three-dimensional network structure, improves creep resistance, and solves the defect of dimensional expansion caused by excessive hygroscopicity and poor creep resistance during use of the nylon wheel of the prior art.

[0027] (2) In the present invention, the intercalation polymerization is carried out between montmorillonite and the nylon matrix. The intercalation polymerization allows the nylon polymer chains to enter the montmorillonite layers, thereby enhancing the interfacial interaction between the two and effectively preventing the chain segments of the matrix from sliding when subjected to stress, thereby improving the tensile strength and bending modulus of the material. Compared with the existing technology, the montmorillonite nanosheets can play a role in stress concentration and dispersion in the matrix. When the material is impacted by external force, the matrix around the nanosheets can absorb and dissipate more energy, thereby improving the impact toughness and elongation at break of the material.

[0028] (3) In the present invention, imidazole ionic liquid modifies montmorillonite through ion exchange, and its carbon chain is inserted into the interlayer of montmorillonite and covers the surface, forming a hydrophobic microenvironment. Compared with the existing technology, the layered structure of montmorillonite can physically block water penetration. At the same time, the hydrophobic groups of the ionic liquid reduce the contact opportunity between the amide bonds in nylon and water, thereby reducing the overall hygroscopicity. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments described in the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive efforts.

[0030] Figure 1 It is a method step diagram of a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0032] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0033] A modified cast nylon wheel, wherein the raw materials of the modified cast nylon wheel include, by weight, 80-120 parts of caprolactam monomer, 8-12 parts of a first ionic liquid, 2-4 parts of modified montmorillonite, 0.1-1 parts of a catalyst, and 0.1-1 parts of a co-catalyst;

[0034] The first ionic liquid is a pyridine ionic liquid, the modified montmorillonite includes a montmorillonite body and a second ionic liquid, the montmorillonite body is one of sodium-based montmorillonite and calcium-based montmorillonite, and the second ionic liquid is an imidazole ionic liquid.

[0035] A modified cast nylon wheel comprises raw materials including caprolactam monomer, a first ionic liquid, modified montmorillonite, a catalyst and a co-catalyst. The modified montmorillonite comprises a montmorillonite body and a second ionic liquid. The interfacial bonding strength between the montmorillonite and the nylon matrix is enhanced, the load transfer efficiency is improved, the creep deformation rate is significantly slowed, and the modified montmorillonite extends the permeation path of water molecules. The montmorillonite treated with the second ionic liquid forms a nano-layered structure that is uniformly dispersed in the nylon matrix, constructing a dense "maze effect" and reducing hygroscopicity. The ionic liquid promotes the formation of chemical bonds between molecular chains during polymerization, constructing a three-dimensional network structure and improving creep resistance. This solves the problem of dimensional expansion caused by excessive hygroscopicity and poor creep resistance during use of nylon wheels for port cranes in the prior art.

[0036] Nylon's strong hygroscopicity stems from hydrogen bonding between polar amide bonds in the molecule and water molecules. Water absorption easily leads to dimensional expansion and a decrease in mechanical properties. Imidazole ionic liquids can modify montmorillonite through ion exchange, inserting their carbon chains between the montmorillonite layers and covering the surface, creating a hydrophobic microenvironment. When this organic montmorillonite is dispersed in a nylon matrix, the montmorillonite's layered structure physically blocks water penetration. Simultaneously, the hydrophobic groups in the ionic liquid reduce the contact between the amide bonds in the nylon and water, reducing overall hygroscopicity.

[0037] Pyridinium ionic liquids have long hydrophobic carbon chains. These hydrophobic groups work together with the hydrophobic groups of imidazolium ionic liquids to further enhance the hydrophobicity between and on the surface of the montmorillonite. The increased hydrophobic groups make it more difficult for water molecules to access and penetrate the montmorillonite layers, thereby reducing the hygroscopicity of the nylon matrix. The hydrophobic groups of these two ionic liquids form a denser, more uniform hydrophobic layer on the montmorillonite surface, effectively preventing water molecules from contacting both the montmorillonite and the nylon matrix. This synergistic effect creates a more stable and effective hydrophobic microenvironment, further reducing the chance of water molecules invading.

[0038] The mass ratio of the montmorillonite base to the second ionic liquid in the modified montmorillonite is 80-95:5-20. Within this mass ratio, the montmorillonite treated with the second ionic liquid forms a nano-layered structure and can be evenly dispersed within the nylon matrix, creating a denser "maze effect." This makes the permeation path of water molecules within the nylon wheel extremely tortuous and lengthy, effectively reducing the wheel's ability to absorb water molecules and minimizing dimensional changes caused by moisture absorption.

[0039] When the amount of montmorillonite and the second ionic liquid is within this ratio, the modified montmorillonite is well dispersed in the nylon matrix while maintaining the integrity of the barrier structure. If the amount of montmorillonite is too high and the second ionic liquid is too low, the nano-layered structure cannot be fully formed, resulting in a poor barrier effect. Conversely, if the amount of montmorillonite is too low and the second ionic liquid is too high, agglomeration and other problems will occur, affecting uniform dispersion and hindering the formation of a good labyrinth structure to block water molecules.

[0040] At this mass ratio, the interfacial bonding strength between the montmorillonite and the nylon matrix is enhanced, improving load transfer efficiency. This allows the nylon wheel to more evenly distribute internal stress when subjected to the long-term loads of port crane operation, reducing deformation caused by localized stress concentration, thereby slowing the creep deformation rate and minimizing the dimensional expansion caused by poor creep resistance.

[0041] Within this ratio, the second ionic liquid interacts better with the montmorillonite matrix. During the polymerization process, it synergizes with the first ionic liquid and molecules in the nylon matrix, more effectively promoting the formation of chemical bonds between molecular chains and building a three-dimensional network structure. This three-dimensional network structure enhances the overall stability and rigidity of the nylon wheel, improves creep resistance, and helps address dimensional expansion issues.

[0042] The structural formula of the first ionic liquid is:

[0043]

[0044] Wherein R1 and R2 are respectively one of methyl, ethyl, butyl and acetoxy, X - It is one of chloride ion, bromide ion and boron tetrafluoride. - The choice of the first ionic liquid can regulate the interaction between the nylon matrix and the modified montmorillonite. A suitable ionic liquid can improve compatibility with the nylon matrix and improve the dispersion of the modified montmorillonite in the nylon matrix, making the "maze effect" more pronounced and the water molecule permeation path more tortuous and complex, further reducing hygroscopicity.

[0045] During the polymerization process, the presence of the first ionic liquid can promote the formation of chemical bonds between molecular chains and build a three-dimensional network structure. - The choice of ionic liquid affects the interaction mode and strength between the nylon molecular chains. Suitable ionic liquids can more effectively promote crosslinking between nylon molecular chains, making the network structure denser, thereby improving the creep resistance of the nylon wheel, slowing the creep deformation rate, and reducing the dimensional expansion caused by poor creep resistance.

[0046] By adjusting R1, R2 and X - The first ionic liquid strengthens the interfacial bonding between the montmorillonite and the nylon matrix. This good interfacial bonding improves load transfer efficiency, allowing the stress to be more evenly distributed between the matrix and the montmorillonite when the nylon wheel is loaded. This prevents deformation caused by localized stress concentration, improves creep resistance, and reduces the possibility of dimensional expansion.

[0047] The structural formula of the second ionic liquid is:

[0048]

[0049] Where R is C n H 2n SO3H (n is an integer, 1≤n≤4), Y - It is one of chloride ion, bromide ion, iodide ion and acetate. The R group has a certain hydrophobicity. After combining with the montmorillonite body, it can enhance the overall hydrophobicity of the modified montmorillonite. - When it is chloride ion, bromide ion, iodine ion or acetate ion, these anions are combined with the R group to further enhance the hydrophobicity of the modified montmorillonite, effectively delay the penetration path of water molecules in the nylon wheel, reduce hygroscopicity, and reduce the dimensional expansion caused by moisture absorption.

[0050] At the appropriate R and Y -In combination, the second ionic liquid improves the dispersion of the montmorillonite in the nylon matrix. Good dispersion helps create a denser and more uniform "maze effect," making it more difficult for water molecules to penetrate the nylon wheel. It also helps enhance the interaction between the montmorillonite and the matrix, creating conditions for improved creep resistance.

[0051] During the polymerization reaction, the R and Y - The structure helps promote the formation of chemical bonds between nylon molecular chains, building a three-dimensional network structure. This enhances the overall strength and rigidity of the nylon wheel, making it less susceptible to creep deformation when bearing loads, thereby delaying dimensional expansion.

[0052] Appropriate R and Y - The combination can enhance the interfacial bonding strength between the montmorillonite body and the nylon matrix. Good interfacial bonding can improve load transfer efficiency, make the stress distribution of the nylon wheel more uniform during use, reduce deformation caused by local stress concentration, improve creep resistance, and reduce the risk of dimensional expansion.

[0053] The catalyst is one of sodium hydroxide, potassium hydroxide, and sodium carbonate, and the co-catalyst is an isocyanate. These catalysts, sodium hydroxide, potassium hydroxide, and sodium carbonate, are highly alkaline and can effectively catalyze the polymerization of caprolactam monomers, accelerating the reaction rate and converting the monomers into nylon polymers more quickly.

[0054] Isocyanate, acting as a co-catalyst, reacts with active groups such as terminal hydroxyl groups in nylon polymers to form a cross-linked structure. This cross-linked structure increases the rigidity and strength of the nylon wheel, making it less susceptible to creep deformation under long-term loads, effectively solving the dimensional expansion problem caused by poor creep resistance.

[0055] The catalyst and co-catalyst work synergistically to promote the formation of more chemical bonds between nylon polymer chains, building a tighter three-dimensional network structure. This not only improves the overall stability and deformation resistance of the nylon wheel, but also optimizes the stress distribution within the material, enabling the nylon wheel to better withstand the various loads and stresses under the complex operating conditions of port cranes, reducing creep deformation caused by factors such as stress concentration.

[0056] like Figure 1 As shown, a preparation process of a modified cast nylon wheel comprises the following steps:

[0057] S1: The montmorillonite body and the second ionic liquid are placed in water and mixed, and stirred at 60-70°C for 3-4 hours. After separation and drying, they are ground to obtain modified montmorillonite. In step S1, it is ensured that the montmorillonite and the second ionic liquid are fully in contact and react with each other, so that the modified montmorillonite forms a nano-layered structure and can be evenly dispersed in the nylon matrix, thereby enhancing the "maze effect", effectively hindering the penetration of water molecules, reducing the hygroscopicity of the nylon wheel, and reducing the risk of dimensional expansion.

[0058] S2: Place caprolactam monomer and modified montmorillonite in S1 into a reactor at a temperature of 70-85°C and stir for 0.5-2 hours; after vacuum dehydration and adding the first ionic liquid, control the temperature at 135-150°C to react for 0.5-2 hours, which is beneficial for the ionic liquid to promote the formation of chemical bonds between nylon molecular chains, construct a three-dimensional network structure, enhance the barrier to water molecules, and further reduce hygroscopicity.

[0059] Place the caprolactam monomer and the modified montmorillonite in S1 into a reactor and stir at 70-85°C for 0.5-2 hours to fully mix the caprolactam monomer and the modified montmorillonite and conduct a preliminary reaction, which helps to strengthen the interface bonding between the montmorillonite and the nylon matrix, lay a good foundation for subsequent polymerization reaction, improve load transfer efficiency, and delay creep deformation.

[0060] S3: Add the catalyst and co-catalyst to the reactor, control the pressure in the reactor to 0.05-0.1MPa, vacuum dehydrate for 15-30min, add the first ionic liquid, control the temperature to 135-150℃, and continue the reaction for 0.5-2h; perform vacuum dehydration to remove moisture from the mixture to avoid affecting the polymerization reaction and nylon properties, while ensuring that the first ionic liquid fully participates in the reaction, promotes the formation of chemical bonds between molecular chains, and constructs a stable three-dimensional network structure, thereby improving the creep resistance of the nylon wheel, making it less likely to deform under long-term load, and solving the problem of dimensional expansion.

[0061] S4: The contents of the reactor are placed in a nylon wheel mold and centrifuged. After removal, the mold is cooled and solidified to produce a modified cast nylon wheel. Placing the contents of the reactor into the mold and centrifuging it helps eliminate air bubbles, evenly distribute the material, and adhere closely to the mold walls. This ensures a uniform and dense internal structure of the nylon wheel, free of defects or loose areas. After cooling and solidification, the nylon wheel exhibits uniform overall performance and stable creep resistance, further minimizing deformation and dimensional expansion caused by localized stress concentration.

[0062] During the in-situ polymerization of nylon, the functionalized ionic liquid binds to the hydroxyl groups on the montmorillonite surface at one end and reacts with the amide bonds of the nylon at the other end, forming a chemical bond and strengthening the interfacial bonding. This strong interfacial interaction restricts the movement of the nylon molecular chains. Even after absorbing water, the expansion space of the molecular chains is constrained by the montmorillonite nanosheets, thereby reducing volume changes. Furthermore, the uniform dispersion of montmorillonite promoted by the ionic liquid slows the diffusion rate of water in the nylon through a "nanobarrier effect," further reducing volume fluctuations caused by moisture absorption.

[0063] Intercalation polymerization occurs between the montmorillonite and nylon matrix, allowing nylon polymer chains to enter the interlayers of the montmorillonite. This enhances interfacial interaction between the two, effectively preventing chain segment slippage in the matrix under stress and improving the material's tensile strength and flexural modulus. After intercalation polymerization, the montmorillonite nanosheets act as stress concentrators and dispersers within the matrix. When the material is impacted, the matrix surrounding the nanosheets absorbs and dissipates more energy, thereby improving the material's impact toughness and elongation at break.

[0064] During the intercalation polymerization process, chemical or physical interactions occur between the nylon polymer chains and the montmorillonite layers, forming a tight interfacial bond. This interaction enhances the stability of the montmorillonite interlayer structure, allowing the layered structure to be more evenly dispersed within the nylon matrix, creating a denser physical barrier that effectively blocks water penetration and provides a good foundation for the formation of a hydrophobic microenvironment.

[0065] After intercalation polymerization, the montmorillonite nanosheets form complex, tortuous pathways within the nylon matrix, making it difficult for water molecules to diffuse and penetrate rapidly within the material. This reduces the material's hygroscopicity and mitigates the dimensional expansion and performance changes caused by moisture absorption. The presence of the montmorillonite nanosheets in the matrix physically restricts the movement of the nylon polymer segments, making it more difficult for the segments to slide and shift under long-term loads, thereby improving the material's creep resistance and reducing the degree of deformation of the nylon wheel during use. Good intercalation polymerization creates a tighter interface between the montmorillonite and the matrix, allowing for more efficient load transfer between the two, avoiding premature deformation and failure caused by localized stress concentration, and further improving the dimensional stability and creep resistance of the nylon wheel.

[0066] The mass ratio of the combined mass of the montmorillonite and the second ionic liquid to water is 1:5-10. Within this mass ratio, the second ionic liquid is fully spread and coated on the montmorillonite surface. Sufficient water allows the montmorillonite and second ionic liquid to form a stable suspension dispersion upon mixing, allowing the second ionic liquid to be evenly distributed on the montmorillonite surface. After subsequent drying and grinding, the modified montmorillonite forms a nano-layered structure with excellent hydrophobicity, effectively slowing the penetration path of water molecules into the nylon wheel, reducing hygroscopicity, and minimizing the risk of dimensional expansion.

[0067] This mass ratio facilitates the full dispersion of the montmorillonite in the aqueous medium, preventing agglomeration. The evenly dispersed montmorillonite allows for full contact and reaction with the second ionic liquid, allowing the modified montmorillonite to disperse even more evenly within the nylon matrix when subsequently composited with it. This creates a dense "maze effect," further reducing hygroscopicity and laying the foundation for improved creep resistance.

[0068] This ensures ample reaction space and medium for the montmorillonite and the second ionic liquid, while also preventing excessive water from hindering subsequent separation and drying, or introducing excessive impurities that could affect subsequent polymerization. Furthermore, the appropriate amount of water facilitates control of the viscosity and fluidity of the reaction system, ensuring uniform mixing and allowing the montmorillonite and second ionic liquid to fully react and maximize their modified properties, thereby better addressing hygroscopicity and creep resistance issues.

[0069] The milling process parameters in S1 are: a milling speed of 300-500 r / min and a milling time of 20-40 minutes. Milling within this speed range effectively breaks down aggregates of the montmorillonite and the second ionic liquid, resulting in gradually finer particles. This speed also ensures milling efficiency while avoiding excessive heat generation, which could adversely affect the structure and properties of the montmorillonite and ionic liquid, such as volatilization of the ionic liquid or destruction of the montmorillonite layered structure.

[0070] Appropriate grinding parameters result in fine and uniform modified montmorillonite particles. When compounded with the nylon matrix, they are more densely packed into the matrix, forming a more uniform nanoscale layered structure. This enhances the "maze effect," further extending the water molecule permeation path, reducing the hygroscopicity of the nylon wheel, and minimizing dimensional expansion caused by moisture absorption. The fine and uniform modified montmorillonite particles bond more tightly to the nylon matrix, improving interfacial bonding strength and load transfer efficiency. This evenly distributes stress between the matrix and the montmorillonite, minimizing deformation caused by localized stress concentration. Furthermore, good dispersion facilitates the construction of a stable three-dimensional network structure, enhancing the nylon wheel's creep resistance and reducing the risk of dimensional expansion.

[0071] The S4 centrifuge operates at a speed of 200-400 rpm. This effectively removes bubbles from the reactor after the material is poured into the mold, making the nylon wheel more compact and reducing pores and defects. This reduces the penetration of water molecules into the nylon wheel, reduces hygroscopicity, and minimizes the risk of dimensional expansion.

[0072] This ensures uniform distribution of reactants within the mold, particularly the modified montmorillonite and ionic liquid, within the nylon matrix. The uniformly dispersed modified montmorillonite forms a stable three-dimensional network, enhancing the overall stability and creep resistance of the nylon wheel, making it less susceptible to deformation under long-term loads and reducing dimensional expansion. A suitable centrifugal speed helps to make the nylon wheel's internal structure more uniform and dense, optimizing internal stress distribution. During use, the nylon wheel maintains consistent performance across all parts, evenly bearing loads and stresses. This prevents deformation and dimensional expansion caused by localized stress concentration, thereby extending its service life.

[0073] The S4 centrifugation time is 2-4 minutes. This ensures that the contents of the reactor are evenly distributed within the mold, while also ensuring a close fit to the mold walls, minimizing internal porosity and defects. The dense structure effectively reduces the penetration of water molecules into the nylon wheel, thereby reducing hygroscopicity and the risk of dimensional expansion due to moisture absorption.

[0074] Modified montmorillonite and ionic liquids can be evenly dispersed in the nylon matrix to form a stable three-dimensional network structure. This uniform distribution of ingredients helps improve the overall stability and rigidity of the nylon wheel, allowing it to more evenly transfer stress under long-term loads, reduce local stress concentration, enhance creep resistance, and reduce dimensional expansion.

[0075] Proper centrifugation time can avoid problems such as uneven distribution caused by too short a centrifugation time or material stratification caused by too long a centrifugation time, ensuring a uniform and dense internal structure of the nylon wheel. This helps optimize the nylon wheel's overall performance, enabling it to better resist the effects of moisture absorption and creep deformation under the complex operating conditions of port cranes, reduce dimensional expansion, and extend its service life.

[0076] The specific types and sources of the materials in the following examples are shown in Table 1.

[0077] Table 1 Specific types and sources of materials in Examples and Comparative Examples

[0078]

[0079] Example 1: This example provides a modified cast nylon wheel. The modified cast nylon wheel raw materials include, by weight, 120 parts of caprolactam monomer, 6 parts of a first ionic liquid, 2 parts of modified montmorillonite, 0.5 parts of a catalyst, and 0.5 parts of a co-catalyst.

[0080] The first ionic liquid is a pyridine ionic liquid, the modified montmorillonite comprises a montmorillonite base and a second ionic liquid, the montmorillonite base is sodium montmorillonite, and the second ionic liquid is an imidazole ionic liquid. The raw material weight ratio of the montmorillonite base to the second ionic liquid in the modified montmorillonite is 4:1.

[0081] A process for preparing a modified cast nylon wheel comprises the following steps:

[0082] S1: Montmorillonite and the second ionic liquid are placed in water and mixed, and stirred at 70°C for 4 hours. After separation and drying, they are ground to obtain modified montmorillonite; the mass ratio between the total mass of the montmorillonite and the second ionic liquid and water is 1:10, and the grinding process parameters are: grinding speed of 400 r / min, and grinding time of 30 min.

[0083] S2: Place caprolactam monomer and the modified montmorillonite in S1 into a reactor at a temperature of 85° C. and stir for 1 hour;

[0084] S3: Add the catalyst and co-catalyst to the reactor, control the pressure in the reactor to 0.05 MPa, vacuum dehydration for 30 minutes, add the first ionic liquid, control the temperature to 140° C., and continue the reaction for 1 hour; the catalyst is sodium hydroxide and the co-catalyst is isocyanate.

[0085] S4: The material in the reactor is placed into a nylon wheel mold and centrifuged at a centrifugal speed of 300 rpm for 3 minutes. The material is taken out and cooled and solidified to obtain a modified cast nylon wheel.

[0086] The structural formula of the first ionic liquid is:

[0087]

[0088] Wherein R1 and R2 are methyl and acetyl respectively, X - Boron tetrafluoride root.

[0089] The structural formula of the second ionic liquid is:

[0090]

[0091] Where R is C2H4SO3H, Y - For iodide ion.

[0092] Example 2: This example differs from Example 1 in that the mass fraction of the first ionic liquid is 8 parts, and the rest are the same.

[0093] Example 3: This example differs from Example 1 in that the mass fraction of the first ionic liquid is 10 parts, and the rest are the same.

[0094] Example 4: This example differs from Example 1 in that the mass fraction of the first ionic liquid is 12 parts, and the rest are the same.

[0095] Example 5: This example differs from Example 1 in that the mass fraction of the first ionic liquid is 14 parts, and the rest are the same.

[0096] Example 6: This example differs from Example 3 in that the mass fraction of the modified montmorillonite is 1 part, and the rest are the same.

[0097] Example 7: This example differs from Example 3 in that the mass fraction of the modified montmorillonite is 3 parts, and the rest are the same.

[0098] Example 8: This example differs from Example 3 in that the mass fraction of the modified montmorillonite is 4 parts, and the rest are the same.

[0099] Example 9: This example differs from Example 3 in that the mass fraction of the modified montmorillonite is 5 parts, and the rest are the same.

[0100] Comparative Example 1: This comparative example provides a preparation process of a nylon wheel, and the preparation process is as follows:

[0101] 120 parts by mass of caprolactam monomer and 0.5 parts by mass of sodium hydroxide were placed in a reactor, the pressure in the reactor was controlled at 0.05 MPa, vacuum dehydration was carried out for 30 minutes, the temperature was controlled at 140°C, and the reaction was carried out for 1 hour. The substances in the reactor were placed in a nylon wheel mold and centrifuged at a centrifugal speed of 300 rpm for 3 minutes. After being taken out and cooled and solidified, a modified cast nylon wheel was obtained.

[0102] Samples of equal volume from Examples 1 to 9 and Comparative Example 1 were tested for creep resistance and water absorption, respectively. The creep resistance test was conducted in accordance with ISO 899 at 60°C for 1000 h, and the water absorption test was conducted in accordance with GB / T 1034-2008. The test data are shown in Table 2.

[0103] Table 2 Creep resistance test and water absorption test of Examples 1 to 9 and Comparative Example 1

[0104]

[0105] As can be seen from Table 1, the tensile creep moduli of Examples 1 to 9 are all greater than that of Comparative Example 1, and the water absorption rates are all less than that of Comparative Example 1, which shows that the present application has superiority.

[0106] In Examples 1 to 5, as the mass fraction of the first ionic liquid gradually increases, the creep resistance and moisture absorption resistance first increase and then decrease. This is because as the mass fraction of the first ionic liquid increases, its ability to promote the formation of chemical bonds between nylon molecular chains is enhanced, and the constructed three-dimensional network structure is denser, which limits the movement of nylon molecular chains, making the nylon wheel less prone to creep deformation under long-term load. The appropriate amount of the first ionic liquid synergistically acts with the second ionic liquid and montmorillonite to form a denser and more uniform hydrophobic layer on the surface of the montmorillonite, effectively preventing moisture from entering the montmorillonite. The first ionic liquid can enhance the contact between the montmorillonite and the nylon matrix, while enhancing the hydrophobicity between the montmorillonite layers and on the surface, making it more difficult for water molecules to approach and penetrate the montmorillonite layer. However, if the amount of the first ionic liquid is too high, the flexibility of the nylon matrix will decrease, the material will become brittle, and local stress concentration will occur more easily when subjected to load, resulting in defects such as microcracks within the material, which in turn reduces the creep resistance. Excessive first ionic liquid will destroy the interface between the montmorillonite and the nylon matrix, resulting in defects or pores at the interface, making it easier for water molecules to penetrate into the nylon matrix, thereby reducing the anti-hygroscopic property. The preferred embodiment is embodiment three.

[0107] In Examples 3 and 6 to 9, as the mass fraction of modified montmorillonite gradually increases, the creep resistance and hygroscopic resistance both increase first and then decrease. This is because an appropriate increase in the mass fraction of modified montmorillonite can further enhance the interfacial bonding strength between the montmorillonite and the nylon matrix, making the load transfer more uniform, reducing stress concentration, and thus slowing the creep deformation rate. The nano-layered structure formed by the modified montmorillonite is more evenly dispersed in the nylon matrix, building a denser three-dimensional network structure, restricting the movement of nylon molecular chains, improving the rigidity and stability of the material, and thus improving the creep resistance. The formed nano-layered structure is denser and more uniform in the nylon matrix, building a more complex "maze effect", making the penetration path of water molecules in the nylon wheel more tortuous and lengthy, prolonging the time for water molecule penetration, reducing the nylon wheel's adsorption capacity for water molecules, and thus improving the hygroscopic resistance.

[0108] The first ionic liquid and the second ion work together to enhance the interfacial bonding between the montmorillonite and the nylon matrix. The first ionic liquid promotes chemical bonds between nylon molecular chains, building a three-dimensional network structure, while the second ionic liquid-modified montmorillonite provides physical support and restraint. This synergistic effect makes the nylon wheel more stable under long-term loads and improves creep resistance.

[0109] When the mass fraction of modified montmorillonite is too high, its dispersibility in the nylon matrix deteriorates and agglomeration occurs. Agglomerated montmorillonite cannot effectively participate in the stress dispersion of the matrix, but instead becomes a source of stress concentration, causing defects such as microcracks to form within the material, thereby reducing creep resistance. Agglomeration causes pores and defects to appear within the material, which provide new channels for water molecules to penetrate, making it easier for water molecules to enter the nylon matrix, thereby reducing moisture absorption resistance. Excessive montmorillonite indicates that too much second ionic liquid will destroy the interfacial bonding between the montmorillonite and the nylon matrix, reducing load transfer efficiency, reducing creep resistance and improving moisture absorption. The preferred embodiment is Example 7.

[0110] The above description is based on the ideal embodiment of the present invention. Based on the above description, relevant personnel can make various changes and modifications without departing from the technical scope of this invention. The technical scope of this invention is not limited to the content of the specification and must be determined according to the scope of the claims.

Claims

1. A modified cast nylon wheel, characterized in that: The modified cast nylon wheel raw material comprises, by weight, 80-120 parts of caprolactam monomer, 10-12 parts of a first ionic liquid, 2-4 parts of modified montmorillonite, 0.1-1 parts of a catalyst, and 0.1-1 parts of a co-catalyst; The first ionic liquid is a pyridine ionic liquid, the modified montmorillonite comprises a montmorillonite body and a second ionic liquid, the montmorillonite body is one of sodium montmorillonite and calcium montmorillonite, and the second ionic liquid is an imidazole ionic liquid; the raw material mass ratio of the montmorillonite body to the second ionic liquid in the modified montmorillonite is 80-95:5-20; The structural formula of the first ionic liquid is: ； Wherein R1 and R2 are respectively one of methyl, ethyl, butyl and acetoxy, X - It is one of chloride ion, bromide ion and boron tetrafluoride root; The structural formula of the second ionic liquid is: ； Where R is C n H 2n SO3H, n is an integer, 1≤n≤4, Y - It is one of chloride, bromide, iodide and acetate; The preparation process of the modified cast nylon wheel comprises the following steps: S1: Mixing the montmorillonite and the second ionic liquid in water, stirring at 60-70°C for 3-4 hours, separating, drying, and grinding to obtain modified montmorillonite; S2: Place caprolactam monomer and the modified montmorillonite in S1 into a reactor at a temperature of 70-85° C. and stir for 0.5-2 h; S3: Add the catalyst and co-catalyst to the reactor, control the pressure in the reactor to 0.05-0.1 MPa, vacuum dehydrate for 15-30 minutes, add the first ionic liquid, control the temperature to 135-150°C, and continue the reaction for 0.5-2 hours; S4: placing the substance in the reactor into a nylon wheel mold and centrifuging it, taking it out and cooling and solidifying it to obtain a modified cast nylon wheel.

2. The modified cast nylon wheel according to claim 1, characterized in that: The catalyst is one of sodium hydroxide, potassium hydroxide and sodium carbonate, and the co-catalyst is isocyanate.

3. The modified cast nylon wheel according to claim 1, characterized in that: The mass ratio of the total mass of the montmorillonite body and the second ionic liquid to water is 1:5-10.

4. The modified cast nylon wheel according to claim 1, characterized in that: The grinding process parameters in S1 are: grinding speed of 300-500 r / min, and grinding time of 20-40 min.

5. The modified cast nylon wheel according to claim 1, characterized in that: The centrifugal speed in S4 is 200-400 rpm.

6. The modified cast nylon wheel according to claim 1, characterized in that: The centrifugation time in S4 is 2-4 minutes.

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