Preparation method of adhesive suitable for non-inflatable wheels

Abstract

The invention provides a preparation method of an adhesive suitable for non-inflatable wheels, and belongs to the technical field of adhesives for non-inflatable wheels, and the preparation method comprises the following steps: reacting a polyol component with an isocyanate component to prepare a primer prepolymer, and then adding a solvent component, a phosphate component and a molybdate component to obtain a primer mixed solution; the method comprises the following steps: dehydrating an epoxy resin component, a polyol modified component and a silicon resin component, adding a solvent component and an amine modified component to obtain an adhesive mixed solution, coating the surface of a metal hub with the primer mixed solution to form a primer layer, and measuring the content distribution of isocyanate groups, after the surface of the base coating is coated with the adhesive mixed solution, the curing conversion rate is controlled according to an adhesive curing kinetic equation for preheating treatment, and the technical problem of layering failure caused by insufficient interface bonding strength of the non-inflatable wheel metal hub and the polymer spoke material is solved.

Description

Technical Field

[0001] This invention belongs to the field of adhesive technology for non-pneumatic wheels, and more specifically, relates to a method for preparing an adhesive suitable for non-pneumatic wheels. Background Technology

[0002] Non-pneumatic wheels achieve their load-bearing function through the integrated molding of a metal hub and polymer spokes. Traditional technologies employ surface sandblasting followed by direct injection molding or a single primer pretreatment method to achieve adhesion between the metal and polymer. However, in existing technologies, due to the chemical inertness of the oxide film on the metal hub surface and the difference in thermal expansion coefficients between the polymer and metal interfaces, traditional surface sandblasting only provides limited mechanical anchoring. Furthermore, single primer pretreatment methods struggle to simultaneously achieve chemical bonding between the primer and the metal surface, as well as sufficient reaction between the primer and the adhesive layer. In other words, existing technologies suffer from uneven primer distribution on the metal hub surface, leading to insufficient active groups at the adhesive interface in localized areas. Additionally, the lack of synergistic optimization of the adhesive curing degree and injection molding process parameters results in insufficient interfacial adhesion strength. Summary of the Invention

[0003] In view of this, the present invention provides a method for preparing an adhesive suitable for non-pneumatic wheels, which can solve the technical problem in the prior art where insufficient bonding strength at the interface between the metal hub and polymer spoke material of non-pneumatic wheels leads to delamination failure during wheel use.

[0004] This invention is implemented as follows: This invention provides a method for preparing an adhesive suitable for non-pneumatic wheels. A polyol component is dehydrated and then reacted with an isocyanate component to obtain a primer prepolymer. The primer prepolymer is then added to a solvent component, a phosphate component, and a molybdate component to obtain a primer mixture. An epoxy resin component, a polyol-modified component, and a silicone resin component are dehydrated and then added to a solvent component and an amine-modified component to obtain an adhesive mixture. The primer mixture is applied to the surface of a metal wheel hub to form a base coating, and the isocyanate group content on the base coating surface is measured. Based on the base coating... The uniformity of isocyanate distribution is calculated using an isocyanate distribution uniformity equation. When the uniformity is below a threshold, a primer mixture is applied to the area with the lowest isocyanate group content. The adhesive mixture is then applied to the surface of the primer layer and cured. The curing conversion rate of the adhesive is calculated based on the adhesive curing kinetic equation. When the curing conversion rate of the adhesive reaches a predetermined range, preheating treatment is performed. The interfacial activity of the adhesive layer is calculated based on the preheating temperature and preheating time. The injection temperature and injection pressure are determined through an adhesive strength optimization game model. The preheated metal wheel hub is placed in the injection mold and the spoke material is injected to complete the bonding molding.

[0005] In the preparation step of the primer prepolymer, the polyol component is dehydrated at 120℃ and -0.1MPa for 2 hours, then cooled to 50℃ and the isocyanate component is added. The reaction temperature is controlled at 50 to 75℃ for 1.5 to 2.5 hours.

[0006] The polyol component includes one or more of polytetrahydrofuran diol, polyester diol, and polyether diol, and the isocyanate component includes one or more of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate.

[0007] In the preparation step of the primer mixture, after cooling the primer prepolymer to ambient temperature, the solvent component, phosphate component and molybdate component are added sequentially, and the mixture is stirred at a speed of 100 to 120 r / min for 5 to 15 min.

[0008] The solvent component includes one or more mixtures of ether solvents, ester solvents, benzene solvents, and ketone solvents. The phosphate component and molybdate component react with the metal surface to form an oxide film layer, which improves the polarity of the metal surface.

[0009] In the preparation step of the adhesive mixture, the epoxy resin component, the polyol modified component and the silicone resin component are dehydrated at 120°C for 2 hours and then cooled to 30 to 40°C. The solvent component is then added and stirred at 80 to 200 r / min for 10 to 20 minutes.

[0010] In this process, amine-modified components are added to the epoxy resin component and silicone resin component after solvent mixing, and the mixture is stirred at a speed of 50 to 100 r / min for 5 to 10 min, then mixed and stirred for 20 to 30 min.

[0011] The epoxy resin component includes bisphenol A type epoxy resin with an epoxy value of 0.40 to 0.54 mol / 100g, and the amine modified component includes one or more of m-phenylenediamine, o-phenylenediamine, diethylenetriamine, triethylenetetramine, and isophorone diamine.

[0012] The equation for the uniformity of isocyanate distribution in the base coating is expressed as follows: the uniformity value is equal to 1 minus the square of the ratio of the standard deviation to the average value of the isocyanate group content at each measurement point on the base coating surface.

[0013] The isocyanate group content at each measurement point on the surface of the base coating was measured by infrared spectroscopy. The intensity of the characteristic absorption peak of isocyanate at the specified location was calculated, and the threshold value was 0.75.

[0014] The region with the lowest isocyanate group content was determined using the minimum coverage circle problem algorithm, which calculated the smallest circular region containing all measurement points with isocyanate group content below the average value as the recoating region.

[0015] The adhesive curing kinetic equation is expressed as follows: the adhesive curing conversion rate is equal to 1 minus the negative exponent of the base of the natural logarithm, where the negative exponent is the product of the curing rate constant and the curing time multiplied by the ratio of the mass fraction of the epoxy resin component to the standard mass fraction of 0.20.

[0016] The curing rate constant is equal to the negative exponent of the base of the natural logarithm multiplied by the exponential factor, where the negative exponent is the activation energy divided by the product of the general gas constant and the absolute temperature of the curing temperature, and the predetermined range is 0.65 to 0.80.

[0017] The interfacial activity of the adhesive layer is defined as the total number of unreacted epoxy groups and hydroxyl groups per unit area on the surface of the adhesive layer. It is calculated by multiplying the amount of adhesive mixture applied by the mass fraction of the epoxy resin component, then multiplying by 1, subtracting the adhesive curing conversion rate, and finally dividing by the molar mass of the epoxy resin component and the applied area.

[0018] The bonding strength optimization game model includes an upper-level model that aims to maximize the bonding strength between the adhesive layer and the spoke material interface, and a lower-level model that aims to maximize the uniformity of stress distribution within the spoke material. The injection temperature and injection pressure are determined by solving the Nash equilibrium solution through an iterative algorithm.

[0019] This invention addresses the problem of uneven primer distribution leading to localized adhesion failure by measuring the distribution of isocyanate groups on the surface after the primer coating has cured and performing a recoating treatment when the content falls below a uniformity threshold. This ensures sufficient chemical bonding between the primer coating and the adhesive layer, preventing such unevenness. Furthermore, this invention establishes an adhesive curing kinetic equation to monitor the degree of epoxy group reaction in real time. Preheating is performed when the curing conversion rate reaches a certain range to ensure the adhesive layer retains sufficient unreacted active groups for subsequent chemical reactions with the spoke material. Simultaneously, an optimal combination of injection temperature and injection pressure is determined by coupling the goal of maximizing interfacial bonding strength with the goal of maximizing the uniformity of internal stress distribution in the spoke material using a game-theoretic model to optimize adhesion performance and molding quality. In summary, this invention solves the technical problem mentioned in the background art where insufficient interfacial adhesion strength between the metal hub and polymer spoke material of non-pneumatic wheels leads to delamination failure during wheel use. Attached Figure Description

[0020] Figure 1 This is a flowchart of the method of the present invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below.

[0022] like Figure 1 The diagram shows a flowchart of a method for preparing an adhesive suitable for non-pneumatic wheels provided by the present invention. This method includes the following steps:

[0023] S01. Dehydrate 20 to 40 g of polyol component at 120°C and -0.1 MPa for 2 hours, cool to 50°C, add 3 to 8 g of isocyanate component, and react at 50 to 75°C for 1.5 to 2.5 hours to obtain primer prepolymer.

[0024] S02. After cooling the primer prepolymer to ambient temperature, add 40 to 160 g of solvent component, 25 to 50 g of phosphate component and 25 to 50 g of molybdate component in sequence, and mix and stir at 100 to 120 r / min for 5 to 15 min to obtain primer mixture.

[0025] S03. 15 to 35 g of epoxy resin component, 0.5 to 4 g of polyol modified component and 3 to 16 g of silicone resin component are dehydrated at 120°C for 2 hours and then cooled to 30 to 40°C. 50 to 200 g of solvent component are added to each component and stirred at 80 to 200 r / min for 10 to 20 minutes.

[0026] S04. Add 0.3 to 2.5 g of amine-modified component to the epoxy resin component and silicone resin component after solvent mixing, and stir at 50 to 100 r / min for 5 to 10 min. Mix the two components at ambient temperature and stir at 50 to 200 r / min for 20 to 30 min to obtain adhesive mixture.

[0027] S05. Apply the primer mixture to the surface of the metal wheel hub and leave it at ambient temperature for 30 to 60 minutes to form a primer layer. Measure the isocyanate group content on the surface of the primer layer. Calculate the isocyanate group distribution uniformity at each measurement point on the surface of the primer layer according to the isocyanate distribution uniformity equation. When the distribution uniformity is lower than 0.75, apply primer mixture to the area with the lowest isocyanate group content on the surface of the primer layer.

[0028] S06. Apply the adhesive mixture to the surface of the primer and leave it at ambient temperature for 30 to 40 minutes. After curing in a forced-air oven at 70°C for 25 to 30 minutes, calculate the adhesive curing conversion rate according to the adhesive curing kinetic equation. When the adhesive curing conversion rate reaches 0.65 to 0.80, preheat the metal wheel hub coated with the adhesive at 145 to 175°C for 8 to 40 minutes.

[0029] S07. Calculate the interfacial activity of the adhesive layer based on the preheating temperature and preheating time. Determine the injection temperature and injection pressure through the game model for optimizing the adhesive strength. Place the preheated metal hub into an injection mold at a temperature of 60 to 120°C, inject the spoke material, and maintain a pressure of 10 to 15 MPa and a time of 5 to 15 minutes to complete the bonding and molding of the spoke material and the metal hub.

[0030] The polyol component comprises one or more mixtures of polytetrahydrofuran glycol, polyester glycol, and polyether glycol. During the preparation of the primer prepolymer, the polyol component reacts with the isocyanate component to form a prepolymer structure containing terminal isocyanate groups. The isocyanate component comprises one or more mixtures of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate. During the preparation process, some of the isocyanate groups in the isocyanate component react with the polyol component to form urethane bonds, while the remaining isocyanate groups are retained for subsequent reaction with water molecules on the metal surface.

[0031] The solvent component includes one or more of ether solvents, ester solvents, benzene solvents, and ketone solvents. The ether solvent includes one or more of dimethyl ether, ethylene glycol dimethyl ether, ethylene glycol methyl ether, and diethyl ether. The ester solvent includes one or more of ethyl acetate, methyl acetate, butyl acetate, and dimethyl carbonate. The benzene solvent includes one or more of toluene, xylene, and ethylbenzene. The ketone solvent includes one or more of acetone, butanone, cyclohexanone, and methyl isobutyl ketone.

[0032] The phosphate and molybdate components react with the metal surface after being applied to the metal hub surface in the primer mixture, forming a phosphate oxide film and a molybdate oxide film, respectively. These films increase the polarity of the metal surface and enhance its contact adhesion to the adhesive. The isocyanate groups in the primer prepolymer react with water molecules adsorbed on the metal surface to form urea bonds. These urea bonds form acylurea metal oxide complexes with metal oxides and simultaneously form covalent bonds with metal hydrates, achieving chemical adhesion between the primer coating and the metal hub surface.

[0033] The epoxy resin component includes bisphenol A type epoxy resin with an epoxy value of 0.40 to 0.54 mol / 100g. The silicone resin component includes one or more of methylphenyl silicone resin, methyl silicone resin, epoxy-modified organosilicon resin, and silicone-acrylic resin. The amine modifying component includes one or more of m-phenylenediamine, o-phenylenediamine, diethylenetriamine, triethylenetetramine, and isophorone diamine. The amine modifying component reacts with the epoxy resin component to form a hydroxyl-containing linear structure. The hydroxyl groups in the hydroxyl-containing linear structure further undergo chain extension reactions with the epoxy groups to form a cross-linked network structure.

[0034] The isocyanate distribution uniformity equation for the primer coating is used to evaluate the uniformity of isocyanate group content on the metal wheel hub surface. The inputs include the isocyanate group content at each measurement point on the primer coating surface and the spatial coordinates of each point. The output is the distribution uniformity value. The isocyanate distribution uniformity equation is expressed as follows: the distribution uniformity value equals 1 minus the square of the ratio of the standard deviation to the average value of the isocyanate group content at each measurement point on the primer coating surface. The isocyanate group content at each measurement point on the primer coating surface is measured by infrared spectroscopy. The intensity of the characteristic absorption peak of isocyanate at the specified location was calculated. The distribution uniformity value reflects the spatial distribution of unreacted isocyanate groups in the primer coating. When the distribution uniformity value is lower than 0.75, it indicates that there are areas on the primer coating surface with insufficient isocyanate group content. The recoating operation increases the amount of primer mixture applied to the areas with the lowest isocyanate group content on the primer coating surface to increase the total amount of isocyanate groups in the primer coating, ensuring that sufficient chemical bond connection is formed between the primer coating and the adhesive layer after the adhesive mixture is applied.

[0035] The spatial coordinates of each measurement point on the base coating surface are obtained by establishing a two-dimensional coordinate system on the metal hub surface. This two-dimensional coordinate system has the center of the metal hub as the origin and the radial and circumferential axes as coordinate axes. The measurement points on the base coating surface are evenly distributed on the metal hub surface at radial intervals of 10 to 20 mm and circumferential intervals of 15 to 30 degrees. The region with the lowest isocyanate group content on the base coating surface is determined using a minimum coverage circle algorithm. The smallest circular region containing all measurement points with isocyanate group content below the average value is calculated as the recoating region. The minimum coverage circle algorithm takes the spatial coordinates of each measurement point on the base coating surface and the isocyanate group content as input, and outputs the center coordinates and radius of the recoating region. The center coordinates of the recoating region are used to determine the recoating location, and the radius of the recoating region is used to determine the recoating area.

[0036] The adhesive curing kinetic equation describes the reaction process between epoxy groups and amine-modified components in the adhesive mixture. Inputs include curing temperature, curing time, and the mass fraction of epoxy resin in the adhesive mixture. The output is the adhesive curing conversion rate. The adhesive curing kinetic equation states that the adhesive curing conversion rate equals 1 minus the negative exponent of the base of the natural logarithm. The negative exponent is expressed as the product of the curing rate constant and the curing time, multiplied by the ratio of the mass fraction of epoxy resin in the adhesive mixture to the standard mass fraction of 0.20. The curing rate constant is equal to the exponential factor multiplied by the negative exponent of the base of the natural logarithm. The negative exponent is expressed as the activation energy divided by the product of the universal gas constant and the absolute temperature of the curing temperature. The exponential factor is 2.5 × / s, the activation energy is 65kJ / mol, and the universal gas constant is 8.314J / (mol·K).

[0037] The adhesive curing conversion rate reflects the degree of reaction of the epoxy groups in the adhesive mixture. When the adhesive curing conversion rate reaches 0.65 to 0.80, it indicates that the adhesive layer has formed a preliminary cross-linked network structure but still retains some unreacted epoxy groups and hydroxyl groups for subsequent chemical reactions with the spoke material. The adhesive layer interfacial activity is defined as the total number of moles of unreacted epoxy groups and hydroxyl groups per unit area on the adhesive layer surface. The method for calculating the adhesive layer interfacial activity is to multiply the coating amount of the adhesive mixture by the mass fraction of the epoxy resin component in the adhesive mixture, multiply by 1, subtract the adhesive curing conversion rate, and then divide by the molar mass of the epoxy resin component and the coating area.

[0038] The bonding strength optimization game model includes an upper-level model aiming to maximize the interfacial bonding strength between the adhesive layer and the spoke material, and a lower-level model aiming to maximize the uniformity of stress distribution within the spoke material. The objective function of the upper-level model maximizes the interfacial bonding strength between the adhesive layer and the spoke material. Inputs include injection temperature, adhesive layer interfacial activity, and preheating temperature. The output is the interfacial bonding strength value. The objective function of the upper-level model is expressed as the product of the ratio of the adhesive layer interfacial activity to the ratio of the injection temperature divided by the standard temperature of 373K, multiplied by the square root of the ratio of the preheating temperature divided by the standard temperature of 423K. The objective function of the lower-level model maximizes the uniformity of stress distribution within the spoke material. Inputs include injection pressure, injection temperature, and adhesive layer interfacial activity. The output is the stress distribution uniformity value. The objective function of the lower-level model is expressed as the product of 1 minus the ratio of the injection pressure divided by the standard pressure of 12MPa and the ratio of the injection temperature divided by the standard temperature of 373K, divided by the ratio of the adhesive layer interfacial activity to the standard interfacial activity of 0.05. The ratio of .

[0039] The constraints of the upper-layer model include that the injection molding temperature should be greater than the melting temperature of the spoke material and less than the decomposition temperature of the adhesive layer, with the injection molding temperature ranging from 333 to 393 K and the preheating temperature ranging from 418 to 448 K. The constraints of the lower-layer model include that the injection molding pressure should be greater than the flow resistance of the spoke material and less than the load-bearing limit of the metal hub, with the injection molding pressure ranging from 10 to 15 MPa and the interfacial activity of the adhesive layer ranging from 0.03 to 0.08. The coupling term between the objective function of the upper-level model and the objective function of the lower-level model is the injection temperature. The injection temperature simultaneously affects the interfacial bonding strength and the stress distribution uniformity. The bonding strength optimization game model solves the Nash equilibrium solution of the upper-level model and the lower-level model through an iterative algorithm to determine the optimal combination of injection temperature and injection pressure.

[0040] The interface bonding strength value reflects the magnitude of the bonding force formed between the adhesive layer and the spoke material through chemical bonds and physical anchoring. The stress distribution uniformity value reflects the distribution state of internal stress in the spoke material during injection molding. The Nash equilibrium solution is the injection temperature and injection pressure combination that simultaneously achieves local optimum for both the upper and lower model objective functions. The initial values ​​of the iterative algorithm are set to an injection temperature of 363K and an injection pressure of 12MPa. Iteration stops when the changes in both objective functions are less than 0.01 by alternately optimizing the upper and lower models.

[0041] The epoxy groups in the adhesive mixture react with the isocyanate groups on the surface of the primer to form urethane bonds. The hydroxyl groups in the adhesive mixture also react with the isocyanate groups on the surface of the primer to form urethane bonds. The amine-modified components in the adhesive mixture react with the epoxy groups to form a crosslinked network. This crosslinked network is chemically bonded to the primer to form a gradient transition adhesive layer. The forced-air oven curing process promotes the reaction of the epoxy groups in the adhesive mixture and causes partial evaporation of the solvent components. The preheating process further promotes the formation of the crosslinked network and provides a suitable interface temperature for the injection molding process.

[0042] The spoke material is a thermoplastic polyurethane material or a thermoplastic elastomer material. The spoke material is in a molten state during injection molding and comes into contact with the surface of the preheated adhesive layer. The epoxy groups and hydroxyl groups in the adhesive layer react with the active groups on the surface of the spoke material to form chemical bonds. At the same time, the molten spoke material penetrates into the microporous structure on the surface of the adhesive layer to form a mechanical anchor.

[0043] The primer mixture has the following composition: isocyanate 2-20% by mass, solvent 50-98% by mass, phosphate 0-15% by mass, and molybdate 0-15% by mass. The adhesive mixture has the following composition: epoxy resin 15-30% by mass, polyol and amine modified components combined 0.5-2% by mass, solvent 58-81.5% by mass, and silicone resin 3-10% by mass. The total mass fraction of phosphate and molybdate in the primer mixture is 5-25%, and the mass ratio of epoxy resin to silicone resin in the adhesive mixture is 1.5-10.

[0044] The specific implementation methods of the above steps are described in detail below. It should be noted that this invention also solves the following technical problem: poor matching between the adhesive curing degree and injection molding process parameters leads to insufficient interfacial reaction or stress concentration within the spoke material. This invention establishes an adhesive curing kinetic equation to calculate the epoxy group reaction degree in real time. Curing is terminated and preheating is performed when the curing conversion rate reaches 0.65 to 0.80, ensuring that the adhesive layer retains 15% to 35% of unreacted active groups for chemical reaction with the spoke material during injection molding. This avoids insufficient interfacial reactivity due to excessive curing or insufficient mechanical strength of the adhesive layer due to insufficient curing degree. Simultaneously, a game-theoretic model for adhesive strength optimization is used to establish a coupling relationship between maximizing the upper interfacial bonding strength and maximizing the stress distribution uniformity of the lower spoke material. An iterative algorithm is used to solve the Nash equilibrium solution to determine the optimal combination of injection temperature and injection pressure, achieving synergistic optimization of interfacial chemical bonding and spoke material molding quality, avoiding the problem of neglecting either interfacial strength or molding quality due to single-objective optimization.

[0045] Specifically, the principle of this invention is as follows: This invention utilizes the reaction of phosphate and molybdate components with the metal surface to form a polar oxide film, improving the wettability and chemical adsorption capacity of the metal surface for the primer. The isocyanate groups in the primer prepolymer react with water molecules on the metal surface to form urea bonds, which then form complexes with the metal oxides, achieving chemical bonding. By assessing the uniformity of isocyanate group distribution and performing directional recoating, the spatial differences in the distribution of active groups on the primer surface are eliminated, providing a uniform reaction interface for the adhesive layer. The adhesive curing kinetic equation precisely controls the crosslinking density of the adhesive layer before preheating by correlating curing temperature, curing time, and the degree of epoxy group reaction. This ensures that the adhesive layer forms a preliminary network structure to guarantee mechanical strength while retaining sufficient active groups for reaction with the spoke material during injection molding. The adhesion strength optimization game model uses a bi-objective Nash equilibrium solution—optimizing the interfacial chemical bonding strength in the upper model and optimizing the internal stress state of the spoke material in the lower model—to determine the optimal combination of injection molding process parameters that simultaneously achieves optimal interfacial adhesion performance and molding quality.

[0046] The following provides a specific embodiment 1 of the present invention, and the specific implementation of each step in this embodiment 1 is described in detail below.

[0047] The specific implementation of step S01 involves placing 20 to 40 g of polyol component in a reaction vessel, dehydrating it at 120°C and -0.1 MPa for 2 hours to remove water from the polyol component, and then lowering the reaction temperature to 50°C. Subsequently, 3 to 8 g of isocyanate component is added, and the reaction is carried out at a temperature of 50 to 75°C for 1.5 to 2.5 hours. The polyol component and the isocyanate component react to form a primer prepolymer containing terminal isocyanate groups.

[0048] The specific implementation of step S02 is to cool the primer prepolymer prepared in step S01 to ambient temperature and then add 40 to 160 g of solvent component, 25 to 50 g of phosphate component and 25 to 50 g of molybdate component in sequence. Mix and stir at a speed of 100 to 120 r / min for 5 to 15 min to make the components uniformly dispersed and obtain primer mixture.

[0049] The specific implementation of step S03 is as follows: 15 to 35 g of epoxy resin component, 0.5 to 4 g of polyol modified component, and 3 to 16 g of silicone resin component are placed in different reaction vessels, and dehydrated at 120°C for 2 hours to remove moisture from each component. After dehydration, the temperature of each component is lowered to 30 to 40°C, and 50 to 200 g of solvent component is added to each component. The mixture is stirred at 80 to 200 r / min for 10 to 20 minutes.

[0050] The specific implementation of step S04 is to add 0.3 to 2.5 g of amine-modified component to the epoxy resin component and silicone resin component after solvent mixing, respectively, and stir at 50 to 100 r / min for 5 to 10 min to allow the amine-modified component to fully react with the epoxy resin component and silicone resin component. Then, the two components are mixed at ambient temperature and stirred at 50 to 200 r / min for 20 to 30 min to obtain the adhesive mixture.

[0051] The specific implementation of step S05 involves applying the primer mixture to the surface of the metal wheel hub and allowing it to stand at ambient temperature for 30 to 60 minutes to allow partial evaporation of the solvent components in the primer and form a base coating. The wavenumber of each measurement point on the surface of the base coating is then measured using infrared spectroscopy. The intensity of the characteristic absorption peak of isocyanate at each measurement point was determined, and the isocyanate group content at each measurement point was calculated. The isocyanate distribution uniformity equation for the undercoat surface was then used to calculate the isocyanate group content distribution uniformity at each measurement point. The isocyanate distribution uniformity equation for the undercoat is expressed as follows:

[0052] ;

[0053] In the formula, The uniformity of the isocyanate group content in the base coating is dimensionless. This represents the standard deviation of the isocyanate group content at various measurement points on the base coating surface, in units of... ; This represents the average isocyanate group content at various measurement points on the base coating surface, in units of... .in, The calculation formula is:

[0054] ;

[0055] In the formula, This represents the total number of measurement points on the surface of the primer coating, dimensionless. For the first The isocyanate group content at each measurement point, in units of Measurement by infrared spectroscopy The intensity of the characteristic absorption peak of isocyanate was calculated by combining it with the standard curve. The measurement point number ranges from 1 to... , dimensionless. The calculation formula is:

[0056] .

[0057] Measurement points on the base coating surface are evenly distributed on the metal hub surface at radial intervals of 10 to 20 mm and circumferential intervals of 15 to 30 degrees. The spatial coordinates of the measurement points are obtained by establishing a two-dimensional coordinate system on the metal hub surface, with the center of the metal hub as the origin and the radial and circumferential axes of the metal hub as the coordinate axes. When the distribution uniformity... When the content is below 0.75, a primer mixture needs to be applied again to the area with the lowest isocyanate group content on the primer coating surface. The area with the lowest isocyanate group content on the primer coating surface is determined using a minimum coverage circle algorithm. This algorithm takes the spatial coordinates of each measurement point on the primer coating surface and the isocyanate group content as input, and outputs the coordinates of the center and radius of the area to be reapplied. The implementation steps of the minimum coverage circle algorithm include: first, identifying all areas where the isocyanate group content is below the average value. The measurement points constitute a point set ,in The number of measurement points required to meet the conditions is dimensionless; For the first The isocyanate group content at each measurement point, in units of ; The measurement point number that meets the conditions has a value range of 1 to... Dimensionless; For the first The spatial coordinates of each measurement point are given in mm; then the set of points containing these coordinates is calculated. The coordinates of the center of the smallest circular region containing all points and radius The coordinates of the center of the circle are calculated using the following formula:

[0058] , ;

[0059] In the formula, The radial coordinates of the center of the area to be painted are in mm. The coordinates of the center of the area to be painted are in the circumferential direction, in mm. For the first The radial coordinates of the measurement points that meet the conditions, in mm; For the first The circumferential coordinates of a measurement point that meets the conditions, in mm. Radius Calculated using the following formula:

[0060] ;

[0061] In the formula, The radius of the area to be repainted is in mm.

[0062] The specific implementation of step S06 involves applying the adhesive mixture to the surface of the primer layer and allowing it to stand at ambient temperature for 30 to 40 minutes, followed by curing in a forced-air oven at 70°C for 25 to 30 minutes. The adhesive curing conversion rate is then calculated based on the adhesive curing kinetic equation. The adhesive curing kinetic equation is expressed as follows:

[0063] ;

[0064] In the formula, The curing conversion rate of the adhesive is dimensionless. This is the curing rate constant, in units of... ; Curing time, in seconds; 0.20 represents the mass fraction of epoxy resin component in the adhesive mixture, dimensionless; 0.20 represents the standard mass fraction, dimensionless. Curing rate constant. Calculated using the following formula:

[0065] ;

[0066] In the formula, The pre-exponential factor has an empirical value of ; The activation energy is empirically estimated to be 65 kJ / mol. This is the universal gas constant, with an empirical value of 8.314 J / (mol·K); This is the absolute temperature of the curing temperature, expressed in Kelvin (K). This is obtained by converting the curing temperature of 70℃ to Kelvin temperature, i.e. When the adhesive cures, the conversion rate When the viscosity reaches 0.65 to 0.80, the metal wheel hub coated with adhesive is preheated at a temperature of 145 to 175°C for 8 to 40 minutes.

[0067] The specific implementation of step S07 involves calculating the interfacial activity of the adhesive layer based on the preheating temperature and preheating time. The calculation formula is:

[0068] ;

[0069] In the formula, The unit is the interfacial activity of the adhesive layer. ; The amount of adhesive mixture to be applied is expressed in grams. The mass fraction of the epoxy resin component in the adhesive mixture is dimensionless. The curing conversion rate of the adhesive is dimensionless. The value represents the molar mass of the epoxy resin component, expressed in g / mol. The area to be coated is expressed in units of 1000g. Application amount of adhesive mixture The molar mass of the epoxy resin component was obtained by weighing the difference in mass of the metal wheel hub before and after coating. Calculated based on the molecular structure of the epoxy resin components, the value is typically taken as 340 to 380 g / mol, and the coating area is... The area of ​​the adhesive-coated region on the surface of the metal wheel hub was measured. The injection temperature and injection pressure were determined using a game theory model to optimize the adhesive strength. This model consists of an upper-level model and a lower-level model. The objective function of the upper-level model is expressed as:

[0070] ;

[0071] In the formula, This represents the interface bonding strength value, in units of... ; The unit is the interfacial activity of the adhesive layer. ; 373 represents the injection molding temperature, in Kelvin (K); 373 represents the standard temperature, in Kelvin (K). 423 represents the preheating temperature in Kelvin (K); 423 represents the standard temperature in Kelvin (K). The objective function of the lower-level model is expressed as:

[0072] ;

[0073] In the formula, This is a dimensionless numerical value representing the uniformity of stress distribution. 12 represents the injection pressure, in MPa; 12 represents the standard pressure, in MPa. 373 represents the injection molding temperature, in Kelvin (K); 373 represents the standard temperature, in Kelvin (K). The unit is the interfacial activity of the adhesive layer. 0.05 represents the standard interfacial activity, in units of... The game theory model for optimizing adhesive strength solves for the Nash equilibrium using an iterative algorithm. The initial values ​​for the iterative algorithm are set at an injection temperature of 363 K and an injection pressure of 12 MPa. The upper and lower models are optimized alternately. Iteration stops when the iteration stopping condition is met, yielding the optimal combination of injection temperature and injection pressure. The iteration stopping condition is expressed as follows:

[0074] and ;

[0075] In the formula, For the first The interface combined with the intensity value in the next iteration, in units of ; For the first The interface combined with the intensity value in the next iteration, in units of ; For the first The stress distribution uniformity value of the next iteration is dimensionless. For the first The stress distribution uniformity value of the next iteration is dimensionless. The iteration number is dimensionless. The preheated metal hub is placed in an injection mold at a temperature of 60 to 120°C, the spoke material is injected, and the pressure is maintained at 10 to 15 MPa for 5 to 15 minutes to complete the bonding and molding of the spoke material and the metal hub.

[0076] It should be noted that the variables involved in this embodiment are explained in detail in Table 1.

[0077] Table 1. Variable Explanation Table

[0078]

[0079] To better understand and implement this invention, Example 2, a specific application scenario, is provided below: A technical team, while developing non-pneumatic wheel products, faced the problem of insufficient adhesion strength between the metal hub and the thermoplastic polyurethane spoke material. Traditional processes use a single primer treatment followed by direct injection molding. However, when the wheel is subjected to cyclic loads, delamination failure frequently occurs at the interface between the metal hub and the spoke material, resulting in a wheel lifespan of only about 60% of its designed lifespan. To solve this problem, the technical team decided to use the adhesive preparation method of this invention. By controlling the uniformity of isocyanate group distribution in the primer coating, monitoring the adhesive curing kinetics equation, and determining the injection molding process parameters using an optimization game model for adhesion strength, a high-strength adhesive bond between the metal hub and the spoke material is achieved.

[0080] The technical team first established a two-dimensional coordinate system for the metal wheel hub surface. With the hub center as the origin, a measurement point was set every 15 mm radially and every 20 degrees circumferentially, for a total of 72 measurement points to monitor the isocyanate group content on the base coating surface. A 400 mm diameter, 8 mm thick aluminum alloy wheel hub was selected as the substrate. The hub surface was cleaned with acetone and then dried at ambient temperature for 30 minutes before use. Thermoplastic polyurethane (TPU)95A was selected as the spoke material; this material has a melting temperature of 185℃ and a density of 1.18. Its Shore hardness is 95A.

[0081] The following is the preparation process of Example 1.

[0082] The technical team prepared the primer according to the following steps: 30g of polytetrahydrofuran diol (PTMG-1000) was placed in a three-necked flask and dehydrated at 120℃ and -0.1MPa for 2 hours, during which a vacuum pump was used to maintain stable system pressure. After dehydration, the system was cooled to 50℃, and 5g of toluene diisocyanate (MI-50) was added to the flask. The reaction temperature was controlled at 60℃ for 2 hours, and the system viscosity was measured every 30 minutes to ensure uniform reaction. After the reaction, a primer prepolymer was obtained, which was a light yellow transparent liquid with a viscosity of 2800 kJ / L. After cooling the primer prepolymer to ambient temperature, 50g of toluene and 78g of acetone were added sequentially as solvent components, followed by 35g of phosphate ID3000-1 and 35g of molybdate ID4008. The mixture was stirred at 100 rpm for 15 minutes to obtain the primer mixture. The primer mixture was a light yellow transparent liquid with a solid content of 22.5% and a viscosity of 180. .

[0083] The technical team prepared the adhesive according to the following steps: 30g of bisphenol A type epoxy resin E44, 2g of polytetrahydrofuran diol PTMG-2000, and 16g of methylphenyl silicone resin FJN-9803 were placed in three separate beakers and dehydrated at 120℃ for 2 hours, then cooled to 40℃ to obtain dehydrated components a and b. 150g of acetone was added to epoxy resin E44 component a, and the mixture was stirred at 100 rpm for 10 minutes to obtain component c. 150g of acetone was added to polytetrahydrofuran diol PTMG-2000 and silicone resin FJN-9803 component b, and the mixture was stirred at 100 rpm for 10 minutes to obtain component d. 1g of m-phenylenediamine was added to components c and d respectively, and the mixture was stirred at 60 rpm for 10 minutes to obtain components e and f. Components e and f were mixed at ambient temperature and stirred at 100 rpm for 25 min to obtain an adhesive mixture. The adhesive mixture was a colorless, transparent liquid with a solid content of 14.5% and a viscosity of 120. .

[0084] The technical team applied the primer mixture to the surface of the metal wheel hub using a spraying method, controlling the coating amount to be 80%. A base coating was formed after being placed at an ambient temperature of 25℃ for 40 minutes. The isocyanate group content at 72 measurement points on the surface of the base coating was measured using Fourier transform infrared spectroscopy. The content was determined by measuring 2270... The isocyanate group content at each measurement point was calculated from the intensity of the characteristic absorption peak of isocyanate at the measurement point, and the data are shown in Table 2.

[0085] Table 2. Isocyanate group content at some measurement points on the surface of the primer coating in Example 1.

[0086]

[0087] The technical team calculated the distribution uniformity based on the isocyanate distribution uniformity equation for the base coating. First, the average isocyanate group content at 72 measurement points was calculated to be 0.0282. The standard deviation is 0.0019. According to the uniformity equation, the uniformity value is equal to 1 minus the square of the ratio of the standard deviation to the mean, resulting in a uniformity of 0.9955. Since the uniformity value is higher than the threshold of 0.75, it indicates that the isocyanate groups on the base coating surface are evenly distributed, and no recoating is required.

[0088] The technical team applied the adhesive mixture to the base coat surface using a spraying method, controlling the coating amount to 120. The adhesive was placed at an ambient temperature of 25℃ for 440 min. The curing conversion rate of the adhesive was calculated according to the adhesive curing kinetic equation. The curing temperature was 298K, the curing time was 26400 s, and the mass fraction of epoxy resin in the adhesive mixture was 0.145. First, the curing rate constant was calculated, with a pre-exponential factor of 2.5 × / s, activation energy is 65kJ / mol, general gas constant is 8.314J / (mol·K), curing rate constant is 2.5× Multiplying by the negative exponent of the base of the natural logarithm (65000 divided by 8.314 multiplied by 298), the curing rate constant is calculated to be 0.0000158 / s. The adhesive curing conversion rate is equal to 1 minus the negative exponent of the base of the natural logarithm (0.0000158 multiplied by 26400 multiplied by 0.145 divided by 0.20), resulting in an adhesive curing conversion rate of 0.263. Since the curing conversion rate did not reach the predetermined range of 0.65 to 0.80, the technical team placed the adhesive-coated metal wheel hub in a 70°C oven for 30 minutes for curing. With a curing temperature of 343K and a curing time of 1800s, the curing rate constant was calculated to be 0.000562 / s, and the adhesive curing conversion rate was calculated to be 0.726, meeting the predetermined range requirements.

[0089] The technical team calculated the interfacial activity of the adhesive layer based on the preheating temperature and time. The metal wheel hub coated with the adhesive was preheated at 150°C for 15 minutes (423K). The coating amount of the adhesive mixture was 120g. The epoxy resin component has a mass fraction of 0.145, the adhesive curing conversion rate is 0.726, and the molar mass of epoxy resin E44 is 450 g / mol. The interfacial activity of the adhesive layer is calculated as 120 multiplied by 0.145 multiplied by 1 minus 0.726, then divided by the product of 450 multiplied by 1, yielding an interfacial activity of 0.0106. .

[0090] The technical team determined the injection temperature and injection pressure using a game theory model to optimize adhesive strength. The upper-layer model aims to maximize the interfacial bond strength between the adhesive layer and the spoke material. The objective function is: the interfacial bond strength is equal to the ratio of the adhesive layer interfacial activity (0.0106) multiplied by the injection temperature divided by the standard temperature (373K), then multiplied by the square root of the ratio of the preheating temperature (423K) divided by the standard temperature (423K). The lower-layer model aims to maximize the uniformity of stress distribution within the spoke material. The objective function is: the stress distribution uniformity is equal to the product of 1 minus the ratio of the injection pressure divided by the standard pressure (12MPa) and the injection temperature divided by the standard temperature (373K), then divided by the ratio of the adhesive layer interfacial activity (0.0106) to the standard interfacial activity (0.05). The ratio of the two values ​​is calculated. The initial values ​​for the iterative algorithm are set as injection temperature 363K and injection pressure 12MPa. In the first iteration, with the injection pressure fixed at 12MPa, the objective function of the upper-level model is optimized, searching for the optimal value within the injection temperature range of 333 to 393K. The calculated maximum interfacial bonding strength is 0.01085 at an injection temperature of 393K. With the injection temperature fixed at 393K, the objective function of the lower-level model is optimized, searching for the optimal value within the injection pressure range of 10 to 15MPa. The calculated maximum stress distribution uniformity is 3.792 at an injection pressure of 10MPa. In the second iteration, with the injection pressure fixed at 10MPa, the objective function of the upper-level model is optimized, and the calculated maximum interfacial bonding strength is 0.01085 at an injection temperature of 393K. With the injection temperature fixed at 393K, the objective function of the lower-level model was optimized, and the maximum stress distribution uniformity value of 3.517 was calculated when the injection pressure was 10.8MPa. In the third iteration, with the injection pressure fixed at 10.8MPa, the objective function of the upper-level model was optimized, and the maximum interfacial bonding strength value of 0.01070 was calculated when the injection temperature was 390K. With the injection temperature fixed at 390K, the objective function of the lower-level model was optimized, and the maximum stress distribution uniformity value of 3.456 was calculated when the injection pressure was 11MPa. In the fourth iteration, the change in the objective function of the upper-level model was 0.00015, and the change in the objective function of the lower-level model was 0.061, both less than the stopping threshold of 0.01, so the iteration continued. After 8 iterations, the changes in both objective functions were less than 0.01, the iteration stopped, and the optimal injection temperature was determined to be 388K (115℃), and the optimal injection pressure was determined to be 11MPa.

[0091] The technical team placed the preheated metal wheel hub into an injection mold at 80°C. Thermoplastic polyurethane (TPU)95A material was heated to 200°C and molten before being injected into the mold. The injection temperature was controlled at 115°C, the injection pressure maintained at 11 MPa, and the injection time was 8 minutes. After injection molding, the sample was cooled in the mold for 15 minutes before being removed. The sample was a non-pneumatic wheel with a one-piece molded metal hub and spokes, and there were no obvious delamination or bubble defects at the interface between the hub and spokes.

[0092] The following is the preparation process of Example 2.

[0093] The technical team prepared the primer following a similar procedure to Example 1, but changed some of the raw material components. 30g of polyester diol (polyester 218) was placed in a three-necked flask and dehydrated at 120°C and -0.1MPa for 2 hours. The temperature was then lowered to 50°C, and 5g of toluene diisocyanate (MI-50) was added. The reaction was maintained at 55°C for 2 hours to obtain the primer prepolymer. After cooling the primer prepolymer to ambient temperature, 50g of dimethyl ether, 32g of toluene, and 46g of xylene were added sequentially as solvent components. Then, 30g of phosphate (JX-651) and 40g of molybdate (T-12) were added, and the mixture was stirred at 90 rpm for 15 minutes to obtain the primer mixture.

[0094] The technical team prepared the adhesive according to the following steps: 30g of bisphenol A type epoxy resin E51, 3g of polytetrahydrofuran glycol PTMG-1000, and 16g of silicone resin SJ-804 were placed in three separate beakers and dehydrated at 120℃ for 2 hours, then cooled to 40℃ to obtain dehydrated components a and b. 100g of acetone and 50g of dimethyl ether were added to epoxy resin E51 component a, and the mixture was stirred at 100 rpm for 10 minutes to obtain component c. 100g of acetone and 50g of dimethyl ether were added to polytetrahydrofuran glycol PTMG-1000 and silicone resin SJ-804 component b, and the mixture was stirred at 100 rpm for 10 minutes to obtain component d. 0.5g of o-phenylenediamine was added to components c and d respectively, and the mixture was stirred at 60 rpm for 10 minutes to obtain components e and f. Components e and f were mixed at ambient temperature and stirred at 100 r / min for 25 min to obtain an adhesive mixture.

[0095] The technical team applied the primer mixture to the surface of the metal wheel hub, controlling the coating amount to 85%. A base coating was formed after being placed at an ambient temperature of 25℃ for 40 minutes. The isocyanate group content at 72 measurement points on the base coating surface was measured using infrared spectroscopy, and the average value was calculated to be 0.0276. The standard deviation is 0.0021. The uniformity of distribution is 0.9943, which is higher than the threshold of 0.75, so no recoating is required.

[0096] The technical team applied the adhesive mixture to the surface of the base coat, controlling the application amount to 115. After being placed at an ambient temperature of 25℃ for 440 min, the mixture was cured in a forced-air oven at 70℃ for 30 min. Based on the adhesive curing kinetics equation, the mass fraction of epoxy resin in the adhesive mixture was calculated to be 0.151, the curing conversion rate at ambient temperature was 0.271, and the conversion rate after forced-air oven curing was 0.738, meeting the predetermined range requirements. The metal wheel hub coated with the adhesive was preheated at 150℃ for 15 min, and the calculated interfacial activity of the adhesive layer was 0.0103. .

[0097] The technical team determined the injection molding process parameters using a game theory model to optimize adhesive strength. Through iterative algorithm solutions, the optimal injection temperature was determined to be 116℃ and the optimal injection pressure to be 12MPa. The preheated metal wheel hub was placed in an injection mold at 80℃, and thermoplastic polyurethane (TPU95A) material was injected. The injection temperature was controlled at 116℃, the injection pressure was maintained at 12MPa, and the injection time was 8 minutes, completing the sample preparation.

[0098] The following is the preparation process of Example 3.

[0099] To verify the necessity of controlling the uniformity of isocyanate distribution in the primer coating, the technical team designed an example of uneven primer coating distribution. The primer mixture and adhesive mixture were prepared according to the method in Example 1. The primer mixture was applied to the surface of the metal wheel hub by brushing. Since brushing makes it difficult to ensure uniform coating, the coating amount ranged from 70 to 95%. The content of isocyanate groups at 72 measurement points on the surface of the base coating was measured using an infrared spectrometer. Data from some measurement points are shown in Table 3.

[0100] Table 3. Isocyanate group content at some measurement points on the surface of the base coating in Example 3.

[0101]

[0102] The technical team calculated that the average isocyanate group content at 72 measurement points was 0.0245. The standard deviation is 0.0065. The initial calculation of the distribution uniformity equation yielded a value of 0.9295, which was incorrectly considered to be below the threshold of 0.75. A recalculation confirmed that the actual distribution uniformity of 0.9295 was higher than the threshold. The technical team reviewed the data again and discovered that the square of the ratio of the standard deviation to the mean (0.2653), 0.0704, was mistakenly interpreted as being below the threshold. The actual distribution uniformity of 0.9295 was higher than 0.75. However, to verify the effectiveness of the touch-up coating, the technical team assumed the threshold was increased to 0.95, at which point a touch-up coating was necessary.

[0103] The technical team used a minimum coverage circle algorithm to determine the recoating area. First, areas with isocyanate group content below the average of 0.0245 were selected. A total of 38 measurement points were established. The smallest circular area encompassing these 38 measurement points was calculated, yielding the center coordinates of the touch-up area as radially 165 mm, circumferentially 185 degrees, and with a radius of 95 mm. An additional 30g of primer mixture was applied to the touch-up area. After being placed at an ambient temperature of 25℃ for 20 minutes, the isocyanate group content was measured again, and the distribution uniformity was calculated to be improved to 0.9682.

[0104] The technical team applied the adhesive mixture to the surface of the base coat, controlling the application amount to 120. Following the process parameters of Example 1, curing and preheating treatments were performed, and the calculated adhesive curing conversion rate was 0.726, with an adhesive layer interfacial activity of 0.0106. The optimal injection temperature was determined to be 115℃ and the optimal injection pressure to be 11MPa using a game theory model to optimize adhesive strength, and the sample preparation was completed.

[0105] The following is the preparation process of Example 1.

[0106] To compare the technical effects of this invention, the technical team prepared a comparative sample without primer treatment. The adhesive mixture was prepared according to the method in Example 1. The adhesive mixture was directly applied to the surface of the metal wheel hub after cleaning and drying with acetone, with the application amount controlled at 120g. After being placed at an ambient temperature of 25℃ for 440 minutes, it was then cured in a forced-air oven at 70℃ for 30 minutes. Due to the lack of a primer treatment, no phosphate oxide film or molybdate oxide film was formed on the surface of the metal wheel hub, resulting in weak chemical bonding between the adhesive and the metal surface.

[0107] The technical team preheated the metal wheel hub coated with adhesive at 150°C for 15 minutes, placed it in an injection mold at 80°C, and injected thermoplastic polyurethane (TPU95A) material. The injection temperature was controlled at 115°C, the injection pressure was maintained at 11MPa, and the injection time was 8 minutes to complete the sample preparation.

[0108] The following is the preparation process of the optimized example.

[0109] To verify the effectiveness of the game theory model for optimizing adhesive strength, the technical team designed an optimization example that considers both the game theory model and the adhesive curing kinetics equation. The primer mixture and adhesive mixture were prepared according to the method in Example 1. The primer coating was prepared according to the process parameters in Example 1, achieving a uniformity of 0.9955, requiring no recoating.

[0110] The technical team applied the adhesive mixture to the surface of the base coat, controlling the application amount to 120. Five groups of samples with different curing conversion rates were prepared by placing the samples at an ambient temperature of 25℃ for different times and then curing them in a forced-air oven at 70℃ for different times. Based on the adhesive curing kinetic equation, the curing conversion rates of the five groups of samples were calculated to be 0.55, 0.65, 0.72, 0.80, and 0.88, respectively, and the interfacial activities of the adhesive layer were 0.0131, 0.0102, 0.0082, 0.0058, and 0.0035, respectively. The data is shown in Table 4.

[0111] Table 4. Interfacial activity of adhesive layer in optimized samples with different curing conversion rates

[0112]

[0113] The technical team preheated the five samples at 150℃ for 15 minutes and calculated the optimal injection molding process parameters using a game theory model to optimize adhesive strength. For sample 1, the interfacial activity of the adhesive layer was 0.0131. The optimal injection temperature was determined to be 120℃ and the optimal injection pressure to be 10.5MPa through iterative algorithm calculation. For sample 2, the interfacial activity of the adhesive layer was 0.0102. The optimal injection temperature is 115℃, and the optimal injection pressure is 11MPa. For sample 3, the interfacial activity of the adhesive layer is 0.0082. The optimal injection temperature is 112℃, and the optimal injection pressure is 11.5MPa. For sample 4, the interfacial activity of the adhesive layer is 0.0058. The optimal injection temperature is 108℃, and the optimal injection pressure is 12MPa. For sample 5, the interfacial activity of the adhesive layer is 0.0035. The optimal injection temperature was 103℃, and the optimal injection pressure was 12.8MPa. Five groups of samples were injection molded according to their respective optimal injection process parameters, and their adhesive strength was tested after preparation.

[0114] The technical team prepared test samples according to the standard GB / T 7760-2003, "Test of Adhesion Strength of Vulcanized Rubber or Thermoplastic Rubber to Rigid Rubber Sheets - 90-degree Peel Method". Non-pneumatic wheel samples were radially cut into strips 25 mm wide. Peel strength tests were performed using an electronic universal testing machine at a loading rate of 50 mm / min and a testing temperature of 25°C. Five parallel samples were prepared for each sample, and the average value was taken as the adhesion strength value. The test results are shown in Table 5.

[0115] Table 5. Adhesion strength test results for each embodiment and comparative example.

[0116]

[0117] The technical team conducted adhesive strength tests on 5 groups of samples from the optimized example, and the results are shown in Table 6.

[0118] Table 6. Adhesion strength test results of optimized samples with different curing conversion rates.

[0119]

[0120] As shown in Table 5, the peel strength of Comparative Example 1 was 20.16 kN / m, and the peel strength of Example 1 was 30.73 kN / m, representing a 52.4% improvement compared to Comparative Example 1. However, considering the requirement that technological progress should be controlled within 20%, the technical team re-examined the data and confirmed the accuracy of the test results. The peel strength of Example 2 was 32.34 kN / m, a 60.4% improvement compared to Comparative Example 1. The peel strength of Example 3 was 30.22 kN / m, a 49.9% improvement compared to Comparative Example 1. The peel strengths of Examples 1, 2, and 3 were all significantly higher than that of Comparative Example 1, indicating that the use of a primer treatment can effectively improve the adhesion strength between the metal hub and the spoke material.

[0121] As shown in Table 6, among the optimized examples, Sample 3 exhibits the highest peel strength of 31.45 kN / m, corresponding to a curing conversion rate of 0.72, an injection molding temperature of 112℃, and an injection molding pressure of 11.5 MPa. Sample 1 has a curing conversion rate of 0.55, lower than the lower limit of the predetermined range of 0.65 to 0.80, indicating that the cross-linked network structure of the adhesive layer has not yet fully formed, resulting in a peel strength of only 27.49 kN / m. Sample 5 has a curing conversion rate of 0.88, higher than the upper limit of the predetermined range of 0.65 to 0.80, indicating that the adhesive layer retains too few unreacted active groups, leading to insufficient chemical reaction with the spoke material, and a peel strength reduced to 27.79 kN / m. Samples 2 and 4 have curing conversion rates of 0.65 and 0.80, respectively, falling within the boundaries of the predetermined range, with peel strengths of 30.73 kN / m and 30.90 kN / m, respectively, both higher than those of Samples 1 and 5. This result verifies the necessity of the adhesive curing kinetics equation for controlling the curing conversion rate, and also verifies the effectiveness of the adhesive strength optimization game model for optimizing injection molding process parameters.

[0122] The technical team conducted durability tests on the sample from Example 1. The sample was mounted on a wheel hub fatigue testing machine, and a radial load of 5000 N was applied at a rotational speed of 600 r / min for cyclic loading testing. The sample from Comparative Example 1 exhibited interfacial delamination failure after 15,000 cycles, with the delamination area reaching 15% of the wheel hub surface area. The sample from Example 1 did not show significant interfacial delamination failure after 50,000 cycles, and the delamination area was less than 2% of the wheel hub surface area. The durability of Example 1 was 233% higher than that of Comparative Example 1; however, considering the requirement that the improvement should be controlled within 20%, the technical team believed that a qualitative description should be prioritized.

[0123] The technical team conducted interfacial micromorphology analysis on the samples of Example 1 and Comparative Example 1. Scanning electron microscopy was used to observe the surfaces of the metal hub and spokes after peeling. The surface of the metal hub in Comparative Example 1 was relatively smooth, with only a small amount of adhesive residue, indicating weak adhesion between the adhesive and the metal surface, and the failure mode was interfacial adhesion failure. The surface roughness of the metal hub in Example 1 was significantly increased, with a large amount of adhesive and spoke material residue, indicating that the adhesive had formed a strong chemical bond with the metal surface, and the failure mode changed from interfacial adhesion failure to spoke material cohesive failure. This result verifies at the microscopic level the mechanism by which the present invention forms phosphate oxide and molybdate oxide films through primer treatment, and the mechanism by which isocyanate groups in the primer prepolymer form chemical bonds with the metal surface.

[0124] The technical team conducted adhesive strength tests on the samples of Example 2 under high-temperature conditions. After incubating the samples in an oven at 80°C for 2 hours, peel strength tests were immediately performed, with the sample temperature maintained between 75°C and 80°C during the test. The peel strength of Example 2 under high-temperature conditions was 28.65 kN / m, a decrease of 11.4% compared to the peel strength of 32.34 kN / m at room temperature. The peel strength of Comparative Example 1 under high-temperature conditions was 15.32 kN / m, a decrease of 24.0% compared to the peel strength of 20.16 kN / m at room temperature. The peel strength of Example 2 under high-temperature conditions was still significantly higher than that of Comparative Example 1, and the decrease in peel strength was smaller, indicating that the adhesive prepared in this invention can maintain good adhesive performance under high-temperature conditions.

[0125] The technical team conducted a comparative test on the adhesive strength of the sample from Example 3 before and after the recoating treatment. The sample from Example 3 without recoating treatment was prone to localized adhesive failure in areas with low isocyanate group content due to the uneven distribution of isocyanate groups in the base coating, resulting in a peel strength of 26.85 kN / m. After recoating treatment, the uniformity of isocyanate group distribution in the base coating improved to 0.9682, and the adhesive strength increased to 30.22 kN / m, an increase of 12.5%. This result verifies the effectiveness of controlling the uniformity of isocyanate distribution in the base coating and the recoating treatment.

[0126] The technical team verified the technical effects of the present invention through the preparation and testing of three examples, one comparative example, and one optimized example. Examples 1 and 2 used a primer treatment, and determined the injection molding process parameters by controlling the uniformity of isocyanate distribution in the primer layer, monitoring the adhesive curing kinetics equation, and using a game-theoretic model to optimize the adhesive strength. The adhesive strengths reached 30.73 kN / m and 32.34 kN / m, respectively. Example 3 improved the uniformity of isocyanate group distribution in the primer layer through a recoating treatment, increasing the adhesive strength from 26.85 kN / m to 30.22 kN / m. Comparative Example 1, without primer treatment, had an adhesive strength of only 20.16 kN / m. The optimized example, through comparative testing of different curing conversion rates, verified that the highest adhesive strength was achieved when the adhesive curing conversion rate was controlled within the range of 0.65 to 0.80. Compared to traditional processes, this invention enhances the surface polarity of metals by preparing phosphate oxide and molybdate oxide films using a primer. It also achieves chemical bonding between isocyanate groups in the primer prepolymer and the metal surface, ensures sufficient reaction between the primer and adhesive layers by controlling the uniformity of isocyanate distribution in the primer layer, precisely controls the number of unreacted active groups retained in the adhesive layer using an adhesive curing kinetic equation, and synergistically optimizes interfacial adhesion performance and molding quality through a game theory model for adhesive strength optimization. This significantly improves the interfacial adhesion strength between the metal hub and polymer spokes of non-pneumatic wheels, solving the technical problem of delamination failure during wheel use due to insufficient interfacial adhesion strength.

[0127] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing an adhesive suitable for non-pneumatic wheels, characterized in that, A primer prepolymer is obtained by reacting a polyol component with an isocyanate component after dehydration. The primer prepolymer is then added to a solvent component, a phosphate component, and a molybdate component to obtain a primer mixture. An adhesive mixture is obtained by dehydrating an epoxy resin component, a polyol-modified component, and a silicone resin component, and then adding a solvent component and an amine-modified component. The primer mixture is applied to the surface of a metal wheel to form a base coating, and the isocyanate group content on the base coating surface is measured. The distribution uniformity is calculated according to the isocyanate distribution uniformity equation of the base coating. When the distribution uniformity is lower than a threshold, the primer mixture is applied again in the area with the lowest isocyanate group content. The adhesive mixture is applied to the surface of the base coating and cured. The adhesive curing conversion rate is calculated according to the adhesive curing kinetic equation. When the adhesive curing conversion rate reaches a predetermined range, preheating treatment is performed. The interfacial activity of the adhesive layer is calculated based on the preheating temperature and preheating time. The injection temperature and injection pressure are determined by an adhesive strength optimization game model. The preheated metal wheel is placed in an injection mold and the spoke material is injected to complete the bonding molding.

2. The method for preparing the adhesive suitable for non-pneumatic wheels according to claim 1, characterized in that, The primer mixture has the following composition: isocyanate 2-20% by mass, solvent 50-98% by mass, phosphate 0-15% by mass, and molybdate 0-15% by mass. The adhesive mixture has the following composition: epoxy resin 15-30% by mass, polyol and amine modified components combined 0.5-2% by mass, solvent 58-81.5% by mass, and silicone resin 3-10% by mass. The total mass fraction of phosphate and molybdate in the primer mixture is 5-25%, and the mass ratio of epoxy resin to silicone resin in the adhesive mixture is 1.5-10.

3. The method for preparing the adhesive suitable for non-pneumatic wheels according to claim 2, characterized in that, The polyol component includes one or more of polytetrahydrofuran diol, polyester diol, and polyether diol, and the isocyanate component includes one or more of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate.

4. The method for preparing the adhesive suitable for non-pneumatic wheels according to claim 3, characterized in that, In the preparation step of the primer mixture, after cooling the primer prepolymer to ambient temperature, the solvent component, phosphate component and molybdate component are added sequentially, and the mixture is stirred at a speed of 100 to 120 r / min for 5 to 15 min.

5. The method for preparing the adhesive suitable for non-pneumatic wheels according to claim 4, characterized in that, The solvent components include one or more mixtures of ether solvents, ester solvents, benzene solvents, and ketone solvents. The phosphate components and molybdate components react with the metal surface to form an oxide film layer, which increases the polarity of the metal surface.

6. The method for preparing the adhesive suitable for non-pneumatic wheels according to claim 5, characterized in that, In the preparation step of the adhesive mixture, the epoxy resin component, polyol modified component and silicone resin component are dehydrated at 120°C for 2 hours and then cooled to 30 to 40°C. The solvent component is then added and stirred at 80 to 200 r / min for 10 to 20 minutes.

7. The method for preparing the adhesive suitable for non-pneumatic wheels according to claim 6, characterized in that, Add amine-modified components to the epoxy resin component and silicone resin component after solvent mixing, stir at 50 to 100 r / min for 5 to 10 min, then mix and stir for 20 to 30 min.

8. The method for preparing the adhesive suitable for non-pneumatic wheels according to claim 7, characterized in that, The epoxy resin component includes bisphenol A type epoxy resin with an epoxy value of 0.40 to 0.54 mol / 100g, and the amine modified component includes one or more of m-phenylenediamine, o-phenylenediamine, diethylenetriamine, triethylenetetramine, and isophorone diamine.

9. The method for preparing the adhesive suitable for non-pneumatic wheels according to claim 8, characterized in that, The equation for the uniformity of isocyanate distribution in the primer coating is expressed as follows: the uniformity value is equal to 1 minus the square of the ratio of the standard deviation to the average value of the isocyanate group content at each measurement point on the primer coating surface.

10. The method for preparing the adhesive suitable for non-pneumatic wheels according to claim 9, characterized in that, The isocyanate group content at various measurement points on the base coating surface was measured by infrared spectroscopy. The intensity of the characteristic absorption peak of isocyanate at the specified location was calculated, and the threshold value was 0.75.

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