An epoxy floor wet test interface for tire wet performance testing, construction method and application

Abstract

This invention relates to the field of tire performance testing technology, and more particularly to an epoxy flooring wet testing interface, its construction method, and its application for tire wet performance testing. This invention constructs a standardized wet testing interface between a substrate layer and an epoxy flooring layer, and clearly defines the surface roughness and post-treatment methods of the epoxy flooring layer, ensuring the reproducibility of the interface microstructure across different batches and laboratories. Simultaneously, during the testing process, a continuous thin water film is formed and maintained in a controlled manner, effectively suppressing localized dry spots, edge dewetting, and film thickness drift caused by traditional spraying and water addition, thus reducing the randomness and dispersion of wet friction testing from the source. This significantly improves the engineering relevance of the test results, providing more reliable, comparable, and reproducible experimental evidence for optimizing the braking and traction performance of new energy vehicle tires under wet and slippery flooring conditions.

Description

Technical Field

[0001] This invention relates to the field of tire performance testing technology, and in particular to an epoxy flooring wet testing interface, its construction method, and its application for tire wet performance testing. Background Technology

[0002] The safety performance of tires on wet roads, including braking, steering, and starting, essentially depends on the actual contact state and tribological response between the tire tread and the road surface in the presence of water. With the continuous increase in the penetration rate of new energy vehicles (EVs), the intensive development of urban space, and the increased utilization of underground space, the frequency of vehicle operation, low-speed braking, and hill-start parking in indoor scenarios such as underground garages, commercial complexes, and logistics warehouses has significantly increased. Epoxy resin flooring is a common flooring material in these scenarios. It is typically formed on a concrete substrate using epoxy or other resin systems to achieve a smooth, dense, and easy-to-clean surface. Some systems also incorporate inorganic fillers to improve wear resistance and scratch resistance, and are polished to control appearance and feel. In wet or waterlogged conditions, a relatively continuous thin water film easily forms on the epoxy flooring surface, changing the tire-ground contact from a direct "rubber-solid" contact to a composite interface of "rubber-water film-solid," thus causing risks such as low-speed slippage, wheel spin during starting, increased braking distance, and instability when parking on hills. For the research and development of tread compound materials, if there is a lack of testing conditions that can stably reproduce the interface characteristics of "wet smooth epoxy flooring" in the laboratory, the conclusions of material screening and formulation optimization are often difficult to extrapolate to the above-mentioned real application conditions, which in turn affects the efficiency of product development and the reliability of safety performance verification.

[0003] In existing technologies, the mainstream systems related to "wet skid performance evaluation" can be broadly categorized into three types: road-scale, floor / surface material-scale, and material-scale. Among these, the road engineering field has long used full-scale tire-to-surface friction testing to characterize wet skid performance, with the typical example being the locked-wheel test system (AASHTOT242 / ASTME274). This system uses a trailer to carry standardized test tires, performs locked-wheel measurements under specified water supply conditions, and outputs friction / slip-related indicators for road network inspection and anti-skid management. The standard provides clear requirements for the water supply device and water volume to ensure consistency of test conditions. However, the test objects, speed ranges, and water supply methods of the road-scale method generally revolve around pavements with significant macro- and micro-textures, such as asphalt / concrete. Its wet conditions are mostly achieved through "water supply flow rate and nominal conversion," which is not targeted at the interface mechanism of indoor epoxy flooring, which is "smooth, low-roughness, and sensitive to thin water films." When the test scenario shifts to indoor flooring with extremely thin water films, the deviation between the nominal water film and the actual water film in the contact area may amplify repeatability and comparability issues, making it difficult to directly transfer road-scale results to epoxy flooring conditions.

[0004] In the field of indoor hard flooring, a relatively independent anti-slip evaluation system has been established. On the one hand, the British Pendulum method has been standardized as ASTM E303, used to measure surface friction characteristics and output indicators such as BPN / PTV, which can be used for anti-slip grading and material comparison of wet hard floors in the laboratory or on-site. On the other hand, standards such as ANSIA 326.3 focus on the determination of the dynamic coefficient of friction (DCOF) of hard materials under "wet and horizontal" use conditions, providing standardized devices, wetting / cleaning and data processing procedures, and providing a basis for compliance and application guidance of building flooring materials. However, it should be noted that the above-mentioned flooring / material scale methods mostly use rubber sliders or specific test feet as contact bodies, and their service targets are biased towards pedestrian anti-slip or flooring material compliance. They do not directly output key tire mechanics characterization parameters such as the "coefficient of friction-slip ratio (μ–S) curve" of tread materials in small slip zones. At the same time, there are differences between slider materials and tire tread materials in terms of viscoelastic properties, contact mechanics and scale effects, making it difficult for indicators such as BPN / DCOF to directly guide the material-level optimization of tread compound formulations.

[0005] In terms of material scale and bench testing, existing technologies focus more on the structure of the testing device and the controllability of operating conditions. For example, patent document CN102359933A discloses an all-weather tire tread-road friction characteristic testing system and method. This system uses modules such as a rotating disk, loading, sensors, and an environmental chamber to test the friction coefficient between the tire tread and the road surface, and can cover different contact pressures, temperatures, humidity levels, slip speeds, and road condition variations, providing a platform for obtaining friction coefficient curves. Another example is patent document CN104777094A, which discloses a rubber friction performance testing experimental device. This device uses a replaceable simulated road surface within a slide chamber and can introduce media such as water, oil, sand, snow, and ice to create a "road surface environment with impurities," thereby studying the coupling law between rubber friction and factors such as road surface, load, and speed. The common advantage of these solutions is that they allow for control of loading, speed, and some environmental factors in the laboratory, and can achieve multi-condition expansion through replaceable road surfaces or the introduction of media. However, its shortcomings are also quite prominent: First, friction surfaces often use non-representative substrates such as general friction pads, metal, glass, and rough concrete, making it difficult to simultaneously match the surface energy, wetting behavior, and thin water film formation mechanism of epoxy flooring; Second, "wet state" is often simplified to surface water addition or spray water supply, lacking quantifiable constraints and closed-loop control over the thickness, coverage continuity, and stabilization time of the thin water film. This leads to the interface state under thin water film conditions easily drifting with time, local flow field, evaporation, and edge dewetting, thus amplifying test dispersion and weakening material discrimination. Related research and reviews also show that water film thickness has a decisive influence on wet friction; a thin water film can significantly reduce the anti-slip / friction level, and the rate of decrease varies with different surface textures and structures, further highlighting the importance of "film design and control" for repeatable evaluation.

[0006] Targeting the specific working conditions of wet epoxy flooring, which are more closely related to scenarios such as underground parking garages, the applicant has applied for Chinese invention patent CN121113860A, which specifically addresses laboratory testing methods and systems for characterizing the grip performance of tire tread rubber on wet epoxy flooring. The patent proposes to stably maintain a 10–100 μm thin water film on a representative epoxy substrate through online thickness measurement and closed-loop control, obtain the μ–slip rate curve of the small slip zone, and integrate it with the British Pendulum (BPN) results under the same substrate and water film setting to form a comprehensive grip index that can be transferred across laboratories. This aims to solve problems such as insufficient repeatability and comparability caused by thin water film drift, and the disconnect between material-level results and flooring safety indicators. The technical approach of this solution is highly targeted: it emphasizes the measurement and traceability of key variables under thin water film conditions in the chain of "substrate standardization (such as Ra window and contact angle window) - online thickness measurement and closed-loop stability control of thin water film - small slip zone curve acquisition - in-situ fusion with BPN - exponential output and quality control threshold", which has positive significance for improving data consistency and engineering relevance.

[0007] However, from the perspective of engineering applications and industrial testing and promotion, there is still room for further improvement in existing technologies. On the one hand, CN121113860A is more inclined towards a closed-loop solution for the overall testing method and system. It relies on complex hardware and control strategies such as high-sampling-frequency online thickness measurement (e.g., reflection interferometry / dispersion confocal) and atomized spray-micro-scraper coordinated control. Although it can significantly improve film control accuracy, it places higher requirements on the consistency of equipment configuration, sensor selection, installation location and calibration process in different laboratories, resulting in higher costs and implementation barriers. On the other hand, in the broader tire material testing ecosystem, there are various existing testing models and testing modules (different friction gauges, different loading methods, different sample shapes and sizes). If there is a lack of a "universal, replaceable and reproducible wet epoxy flooring test interface (interface sample) and its construction specifications", the portability and compatibility of the method system may still be limited. For example, differences in water distribution methods, effective test area boundary effects, water film edge shrinkage, and local dry spots among different devices will still affect the continuity and stability of the film, thus affecting cross-platform comparability. In other words, in addition to the "method / system closed-loop control membrane", it is also necessary to provide a more easily implementable interface engineering solution from the perspective of "the structure and repeatable construction of the test interface body (wet test interface of epoxy flooring)" to support the comparative evaluation of different test platforms under the unified interface conditions.

[0008] In summary, while existing road scale standards are authoritative, they differ from indoor epoxy flooring thin water film scenarios in terms of objects and boundary conditions; while flooring / material scale standards are applicable to the anti-skid grading of hard surfaces, they are difficult to directly map to the small slip zone characterization indicators of tire tread materials; and while material and bench scale devices have the advantages of controllable working conditions and replaceable road surfaces, they lack quantifiable constraints on the "continuous stability of wet epoxy flooring thin water film," and the substrate surface energy and wetting behavior often do not match. Even though specialized solutions like CN121113860A have significantly enhanced film control and fusion evaluation, a test interface (interface sample) and its construction method are still needed to stably and repeatedly simulate the characteristics of wet, smooth epoxy flooring under laboratory conditions for wider application in laboratory testing. By clearly defining and verifiable limitations on the surface roughness, smoothness, surface energy / wetting characteristics, and wet water film conditions of epoxy flooring, different testing machines and laboratories can obtain consistent interface boundary conditions with a lower threshold, thereby further improving the repeatability, comparability, and engineering relevance of wet performance evaluation of tire materials. Summary of the Invention

[0009] The technical objective of this invention is to provide an epoxy flooring wet test interface and its construction method for tire wet performance testing. By quantifying and repeatably limiting and controlling the surface roughness, wetting / film-forming characteristics, and thin water film thickness and stability of the epoxy flooring interface in the laboratory, the working conditions of wet and smooth epoxy flooring surfaces such as underground parking garages can be stably simulated, thereby improving the repeatability, comparability, and engineering relevance of the wet grip performance test results of tire tread rubber and rubber materials.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] An epoxy flooring wet test interface for tire wet performance testing includes a substrate layer and an epoxy flooring layer disposed on the surface of the substrate layer.

[0012] The epoxy flooring layer is formed by coating and curing a two-component or multi-component epoxy resin system. After curing, it is ground or polished in stages to make its surface roughness Ra 0.05 to 1.0 μm.

[0013] The outer surface of the epoxy flooring layer has surface energy parameters to match the wet film-forming characteristics of the epoxy flooring. The surface energy is expressed as surface free energy γ, which is 25 to 45 mN / m.

[0014] During the test, a continuous water film is formed on the surface of the epoxy floor layer. The thickness of the continuous water film is 10-300 μm, and the continuous water film meets the following verifiable criteria: within the preset effective test area, the water film coverage Cw ≥ 0.95, and Cw is maintained at no less than 0.90 for a continuous test time of no less than 6 minutes.

[0015] Wherein, the water film coverage rate Cw is the ratio of the area continuously covered by the water film in the effective test area to the total area of ​​the effective test area, and the coverage area is determined by any one of optical imaging reflection contrast, laser speckle imaging or capacitance array measurement; and the test interface is provided with an annular limiting film boundary structure along the circumference to suppress water film edge retreat and local dry spot formation, so as to improve the repeatability of wet test conditions.

[0016] Preferably, the annular membrane-limiting boundary structure is: a circumferential barrier, a circumferential capillary membrane-limiting groove, or a combination of a barrier and a capillary membrane-limiting groove, wherein the width of the capillary membrane-limiting groove is 0.2 to 2.0 mm and the depth is 0.1 to 1.5 mm.

[0017] Preferably, the thickness uniformity of the continuous water film satisfies the following condition: the difference between the maximum and minimum values ​​of the water film thickness within the effective test area is not greater than ±20% of the set value of the water film thickness.

[0018] Preferably, the surface free energy γ is achieved by introducing a surface energy regulation layer on the surface of the epoxy floor layer. The surface energy regulation layer is a hydrophilic modified layer, a weakly hydrophobic modified layer, or a gradient composite layer of both.

[0019] Preferably, the substrate layer is any one of concrete slab, steel plate or stainless steel plate, and a primer layer is provided between the substrate layer and the epoxy floor layer to improve adhesion and water immersion stability.

[0020] Preferably, the surface macroscopic tilt angle of the effective test area is 0 to 1°, so as to cooperate with the annular membrane boundary structure to maintain a continuous water film.

[0021] Furthermore, the present invention also provides a method for constructing the test interface, comprising:

[0022] S1. Provide a substrate layer and perform surface treatment;

[0023] S2. Apply and cure the epoxy resin system to form an epoxy floor layer;

[0024] S3. Grind or polish the epoxy flooring surface step by step to make the surface roughness Ra 0.05~1.0μm;

[0025] S4. Perform surface energy regulation treatment on the outer surface of the epoxy flooring layer to make the surface free energy γ 25-45mN / m; S5. Form an annular confined membrane boundary structure in the circumferential direction of the test interface;

[0026] S6. Before testing, water is distributed to form a continuous water film, and the film formation state is calibrated by the coverage rate Cw and / or the uniformity of the water film thickness to ensure that the continuous water film meets the criteria.

[0027] Preferably, the surface energy regulation treatment in step S4 includes any one or more of plasma treatment, hydrophilic agent coating and curing, or weak hydrophobic agent coating and curing, to control the static water contact angle between 20° and 80°.

[0028] Preferably, in step S6, water spraying and water distribution are combined with a uniform film distribution component to form a continuous water film. The uniform film distribution component is any one of a scraper strip, a roller pressing uniform film distribution roller, or an air knife uniform film distribution device.

[0029] Preferably, in step S6, the water film coverage Cw is obtained by optical imaging reflection comparison or capacitance array measurement, and the spray flow rate, spray frequency and / or pressure of the uniform film component are adjusted with Cw as feedback parameter to achieve water film continuity closed-loop calibration.

[0030] Furthermore, the present invention also provides an epoxy flooring wet testing system for tire wet performance testing, comprising:

[0031] A test interface installation platform is used to install the test interface;

[0032] Water distribution assembly is used to supply water to the test interface to form a continuous water film;

[0033] Film formation monitoring component for obtaining water film coverage Cw and / or water film thickness uniformity;

[0034] A control component, connected to the water distribution component and the film formation monitoring component, is used to adjust the water supply parameters according to Cw and / or the uniformity of water film thickness, so that the continuous water film meets the criteria described in this invention.

[0035] Friction / grip testing kit is used to test the wet friction performance of tires, tread rubber samples or rubber materials under continuous water film conditions and output test data.

[0036] Preferably, the film-forming monitoring component is any one or more of an optical imaging module, a laser measurement module, or a capacitor array module; the control component adjusts the water supply parameters by at least any one or more of the following: water supply flow rate, water supply pressure, spray frequency, and pressure of the uniform film component.

[0037] Furthermore, the present invention also provides a method for testing the wet performance of tires using the aforementioned testing system, comprising:

[0038] M1. Install the test interface and start the water distribution assembly to form a continuous water film;

[0039] M2. Obtain water film coverage Cw and / or water film thickness uniformity through film formation monitoring components;

[0040] M3. After the water supply parameters are adjusted in a closed loop by the control component to make the continuous water film meet the criteria, the test phase begins.

[0041] M4. Perform friction / grip test under continuous water film conditions that meet the criteria and output wet performance evaluation index.

[0042] This invention constructs a standardized wet testing interface between the substrate layer and the epoxy flooring layer, and clearly defines the surface roughness (Ra falling within a controlled window) and post-treatment methods of the epoxy flooring layer, enabling the interface micromorphology to be repeatedly reproduced across different batches and laboratories. Simultaneously, during the testing process, a continuous thin water film is formed and maintained in a controlled manner (the film thickness is within a set range and can remain stable), effectively suppressing localized dry spots, edge dewetting, and film thickness drift caused by traditional spraying and water addition, thereby reducing the randomness and dispersion of wet friction testing from the source. Based on the aforementioned stable and measurable traceable boundary conditions, the friction coefficient, slip threshold, and grip differences in the low-speed small slip zone of tire tread rubber / rubber materials under wet and smooth epoxy flooring conditions can be more sensitively amplified and stably distinguished, significantly improving the consistency of ranking among different formulations. At the same time, the test interface material properties are more consistent with real epoxy floors such as underground parking garages, avoiding engineering extrapolation deviations caused by the mismatch between surface energy and film-forming behavior when using asphalt, rough concrete, or metal friction pads. This significantly improves the engineering relevance of the test results, providing more reliable, comparable, and reproducible experimental evidence for optimizing the braking and traction performance of new energy vehicle tires under wet and slippery flooring conditions.

[0043] Figure 1 This is a schematic diagram of the overall structure of the epoxy flooring wet testing system for tire wet performance testing according to the present invention.

[0044] Figure 2 This is a schematic diagram illustrating the film formation monitoring and closed-loop film stabilization control principle of the present invention.

[0045] Figure 3 This is a flowchart illustrating the test interface construction method and wet testing method of the present invention.

[0046] Figure 4 This is a schematic diagram of the water film quality threshold and data quality control judgment process of the present invention. Detailed Implementation

[0047] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present invention.

[0048] I. Terminology Explanation

[0049] 1. Epoxy flooring layer: refers to a resin surface layer formed by coating a two-component or multi-component epoxy resin system (containing epoxy resin, curing agent, and, if necessary, diluent, leveling agent, defoamer, wear-resistant filler, etc.) onto the surface of a substrate layer and then curing it. It can be a self-leveling surface layer, a transparent wear-resistant topcoat layer, or a combination of both.

[0050] 2. Substrate Layer: The base material used to support the epoxy flooring layer, which can be a concrete slab, steel plate, stainless steel plate, or a composite structure thereof. The substrate layer can have its adhesion and water immersion resistance improved by applying a primer / interface agent.

[0051] 3. Surface roughness This refers to the arithmetic mean deviation of the epoxy flooring surface profile along the sampling length, commonly measured using a profilometer. To ensure the characteristics of a smooth, wet pavement, this invention will... Controlled Within the range (preferred) (For simulating smoother floor surfaces).

[0052] 4. Continuous water film: refers to a thin liquid film layer in which water coverage is continuous within the effective test area and no significant dry spots appear. Continuity can be quantified by indicators such as water film coverage, film thickness uniformity, and stabilization time.

[0053] 5. Water film thickness This refers to the vertical distance from the surface of the epoxy flooring layer to the outer surface of the water film. In the wet test of this invention, the water film thickness is typically... (Optimal selection for some small slip conditions) ).

[0054] 6. Water film coverage This refers to the percentage of the effective test area covered by a continuous water film, used to quantitatively characterize the continuity of the water film. Its definition and formula are given below.

[0055] 7. Membrane thickness stability (RMSE): refers to the root mean square error of the water film thickness time series relative to the target thickness, used to characterize the closed-loop membrane stabilization effect.

[0056] 8. Effective test area: refers to the area where the tire / rubber sample makes effective contact with the test interface and is used to output friction / grip data (can be circular, rectangular or annular), and its size is determined by the contact geometry of the testing machine.

[0057] 9. Water distribution assembly: A device used to supply water to the test interface to form a water film, including spray nozzles, atomizing nozzles, titration supply port, supply pipeline, valve group, pump and return liquid, etc.

[0058] 10. Film homogenization components: Mechanical components used to achieve uniformity and thickness setting of water film, such as film scrapers, micro-scrapers, film homogenization rollers, air knives, etc.

[0059] II. System Structure of the Invention

[0060] 2.1 Overall System Composition ( Figure 1 )

[0061] like Figure 1 As shown, the preferred wet testing system of the present invention includes:

[0062] 1) Test Interface Mounting Platform: Used for mounting and positioning the epoxy flooring wet test interface (plate specimen). The platform may have positioning pins, clamping mechanisms, and an adjustable tilt structure. Preferably, the repeatability error is no greater than [value missing]. This facilitates repeated comparative testing.

[0063] 2) Water distribution assembly: Used to supply water to the test interface to form a water film, preferably including a liquid supply pump, a pressure stabilizing unit, a flow meter, a spray / atomizing nozzle, a return tank, and a drain pipe. The water distribution method can be spraying, atomizing, titration spreading, or a combination thereof.

[0064] 3) Film formation monitoring component: used to obtain water film thickness. Coverage And film thickness uniformity, etc. Film formation monitoring components can be:

[0065] 4) Thickness measurement: dispersive confocal, laser displacement, optical reflection interferometry, ultrasonic or capacitive thickness measurement;

[0066] 5) Coverage measurement: Industrial camera optical reflection contrast, laser speckle, infrared reflection, or capacitive array imaging. Monitoring components can be positioned at representative points along the leading edge of the contact area or within the effective area (see...). Figure 2 ).

[0067] 6) Control Component: Connected to the water distribution component and film formation monitoring component, this component is used for closed-loop regulation of water supply parameters and film equalization component parameters to achieve the target water film thickness and maintain continuous stability. The control algorithm can employ PID control or Model Predictive Control (MPC). The control frequency can be determined based on the measurement sampling frequency and system response, with the preferred frequency being... Range (higher frequencies are used for high-precision stabilization of thin water films).

[0068] 7) Friction / Grip Test Assembly: Used to test the friction performance of tire tread rubber samples or rubber materials under stable water film conditions and output data. The friction / grip test assembly can be a reciprocating friction machine, a rotary friction machine, a linear sliding test bench, a block-disc tribometer, or a small-slip servo test bench, etc. The output data must include at least the friction force. Normal force And calculate the coefficient of friction. .

[0069] 2.2 Film Formation Monitoring and Closed-Loop Control Structure ( Figure 2 )

[0070] like Figure 3 As shown, this invention emphasizes the critical issue of "thin water film easy to drift" in wet, smooth epoxy flooring scenarios, and therefore preferably adopts a closed-loop structure of "monitoring-control-execution":

[0071] 1) Measurement point location: The thickness measurement point is preferably located at the leading edge of the contact area. The location reflects the actual water film state that will enter the contact area; the coverage monitoring area can cover the effective test area and leave a boundary redundancy area for identifying edge evaporation.

[0072] 2) Actuator: The actuator shall include at least one of the following components: liquid supply flow / pressure regulation and film equalization component (film scraper / micro-scraper / film equalization roller); in high-precision film mode, the combination of "atomizing jet + micro-scraper gap fine adjustment" is preferred.

[0073] 3) Closed-loop target: The closed-loop target includes film thickness. Reaching the set value (e.g.) And meet the fluctuation threshold; at the same time, the water film coverage rate It reaches the set threshold and does not decrease significantly within a specified time.

[0074] III. Test Interface Structure and Construction Method (e.g.) Figure 3 )

[0075] 3.1 Test Interface Structure

[0076] like Figure 2 As shown, the test interface includes:

[0077] 1) Substrate layer: Concrete slab or metal plate (steel / stainless steel plate), typical dimensions for example Alternatively, it can be selected based on the clamping space of the equipment. wait.

[0078] 2) Primer coating (optional): Used to enhance adhesion and seal substrate pores; primer coating is preferred for concrete slabs.

[0079] 3) Epoxy flooring layer: Formed on top of the base layer, and after curing, it undergoes progressive grinding / polishing to reduce its surface roughness. Controlled .

[0080] 4) Surface energy regulation layer (optional but preferred): used to adjust the surface wetting characteristics to the target window, thereby improving the stability and repeatability of thin water film formation.

[0081] 5) Annular membrane boundary structure (preferred): A barrier or capillary membrane groove is set around the circumference of the effective test area to suppress edge dewetting and local dry spots, and improve the continuous stability of the water film and cross-laboratory consistency.

[0082] The above structure enables the present invention to not only control the "surface morphology" but also control the "liquid film boundary conditions" through the boundary structure, thereby significantly improving the repeatability of wet testing.

[0083] 3.2 Construction Method Steps

[0084] The specific implementation of the construction method is described below using steps S1 to S6:

[0085] S1: Provide a substrate layer and perform surface treatment

[0086] Concrete slab: Surface grinding to remove laitance and loose layer, and to remove oil and dust; moisture content is preferably below 8% (simplified methods can be used to assess this in engineering) to facilitate primer adhesion.

[0087] Metal plates: Degrease (e.g., wipe with ethanol / acetone), sandblast or roughen (optional), then dust removal.

[0088] After the substrate is treated, let it stand until the surface is clean and dry.

[0089] S2: Apply and cure to form an epoxy floor layer

[0090] Choose a two-component or multi-component epoxy system: Component A is epoxy resin and additives, and Component B is a curing agent (amine, anhydride, etc.), mixed according to the supplier's recommended ratio. Coating methods include blade coating, self-leveling, and spraying. Typical wet film thickness... After curing, a dense layer is formed. Curing conditions can include room temperature curing (e.g., ...). (24–72 h) or heat curing (e.g.) (4-12 hours) to ensure complete curing and reduce adhesive debris and micropores generated during subsequent polishing.

[0091] S3: Step-by-step grinding / polishing to control surface roughness

[0092] The key to this invention lies in obtaining the microscopic morphology window of the "wet-state smooth epoxy floor" surface in a repeatable manner. A preferred method is a step-by-step grinding and polishing process of "coarse grinding—fine grinding—polishing."

[0093] 1) Coarse grinding: Use #400~#800 sandpaper / sand disc for wet grinding to eliminate orange peel, ripples and local high points, so that the surface is smooth overall.

[0094] 2) Fine grinding: Use #1000 to #2000 wet grinding to further reduce the surface peak-to-valley difference and reduce the directionality of grinding marks.

[0095] 3) Polishing: Mirror polishing is performed using polishing liquid and a polishing pad to achieve a smooth finish. Enter the target window (e.g.) For more stringent smooth simulations).

[0096] After each stage of polishing, cleaning (rinsing with deionized water and wiping with a dust-free cloth) should be performed to avoid abrasive residue causing artificially high roughness or affecting surface energy. Roughness measurement should be performed in at least three areas of each board and the average value should be taken. If the range is exceeded, adjust to the corresponding polishing level until the range requirement is met.

[0097] S4: Surface Energy Modulation Treatment

[0098] Relying on However, it is not possible to completely guarantee the stable formation and batch-to-batch consistency of the thin water film. Differences in epoxy surface energy and wettability can lead to different spreading states under the same water supply conditions. Therefore, the present invention preferably includes a surface energy regulating layer 104 to ensure that the surface wettability falls within the target window.

[0099] Optional solutions include, but are not limited to:

[0100] 1) Plasma treatment: Low-temperature plasma treatment of the epoxy surface (e.g., air / oxygen plasma, treatment time...) This treatment improves surface polarity and wettability. After treatment, it is recommended to complete the testing or seal the product within the specified time (e.g., within 2 hours) to prevent surface regression.

[0101] 2) Hydrophilic / weakly hydrophobic thin coating: Apply an extremely thin (micron-level) surface energy modifier to stabilize wettability after curing.

[0102] 3) Contact angle window control (preferred index): using deionized water in Measured static contact angle Preferred control at (For "wetland epoxy flooring with good grip", the following options are preferred) The medium wetting window is close to the surface energy state of some underground garage abrasion-resistant topcoats.

[0103] S5: Formation of annular membrane boundary structure

[0104] To suppress edge desaturation and localized dry spots, the present invention preferably provides a film-limiting boundary structure 105 along the circumference of the effective testing area. For example, this can be achieved as follows:

[0105] 1) Peripheral fencing: Forming a perimeter around the effective area. The enclosure can be fixed to the board or platform with water-resistant materials (such as stainless steel rings or water-resistant plastic rings) to form a "water enclosure".

[0106] 2) Capillary limiting groove: An annular groove is machined at the edge of the effective area, with a groove width of... trench depth Capillary action can create a "locking edge" at the liquid film edge, reducing the dewetting rate.

[0107] 3) Combined structure: The combination of enclosure and capillary groove makes it more robust in high-precision thin film working conditions.

[0108] This structure belongs to the category of "liquid film boundary condition engineering," which makes a significant contribution to the stability of thin water films and is a key implementation point of this invention.

[0109] S6: Water distribution forms a continuous water film and calibration is performed.

[0110] The goal of S6 is to bring the water film to an acceptable and traceable stable state before testing. The following process is recommended:

[0111] 1) Initial water distribution: Activate the water distribution component to evenly wet the board surface by spraying or atomizing to form an initial water film.

[0112] 2) Film equalization setting: Activate the film equalization components (scraper strip / micro scraper / film equalization roller / air knife) to set the water film thickness to the target range. .

[0113] 3) Film thickness measurement and closed-loop stability control (optional but preferred): The film thickness is measured in real time by the film formation monitoring component. The control components adjust the water supply and membrane equalization components to ensure the membrane thickness reaches the set value. And it meets the stability threshold. Film thickness stability can be measured by the RMSE index, which is defined as:

[0114] ;

[0115] in, For the first The thickness of the water film obtained from the second sampling; Set the target film thickness value; This represents the number of sampling points.

[0116] Water film coverage determination: The effective area is divided into binary segments using optical imaging or a capacitance array, and the coverage is calculated. :

[0117] ;

[0118] in, To test the area within the effective testing region that is covered by a continuous water film; To determine the total area of ​​the effective testing region.

[0119] 4) Optimization criteria, for example: within the preset test effective area And maintain for a continuous test period of no less than 6 minutes. Not less than 0.90.

[0120] 5) Film thickness uniformity judgment: Sample the film thickness at multiple points within the effective area. If the difference between the maximum and minimum values ​​does not exceed ±20% of the set value, the film is considered uniform. This can be expressed as follows:

[0121] ;

[0122] in, , These represent the maximum and minimum film thicknesses within the effective region, respectively. Target film thickness. Preferred. (Corresponding to ±20%).

[0123] 6) After completing the above calibration, proceed to the testing phase; if any indicator is not met, continue to adjust the water supply / membrane parameters until the quality threshold is met.

[0124] IV. Technical Approach to Wet Friction / Grip Testing

[0125] When the testing method and system of the present invention are used in conjunction, it is preferable to perform the following steps to ensure material comparison and evaluation with "same interface, same film thickness, and traceability".

[0126] 4.1 Sample Preparation

[0127] Tread rubber samples can be vulcanized rubber plates, cylindrical blocks, or standard test blocks, with thicknesses such as... The sample surface can be polished to... To reduce the uncertainty of the sample's surface morphology. The sample in relative humidity Humidify the environment for at least 12 hours.

[0128] 4.2 Pre-test inspection and alignment

[0129] Install the test interface on the platform and check that the film boundary structure is intact and the plate surface is clean and free of contamination. The film formation monitoring component completes zero-point calibration (e.g., thickness baseline under dry plate conditions). The friction / grip test component completes force sensor calibration and zero-point reset.

[0130] 4.3 Stabilized Film and Quality Threshold

[0131] After executing the S6 film stabilization process, the quality threshold judgment is initiated. Figure 4 ):

[0132] like , , If all thresholds are met, the friction test can begin.

[0133] If the requirements are not met, the system will prompt "Add water / Adjust scraper / Adjust spray pressure / Clean panel surface", and re-evaluate;

[0134] If detected during the test Significant decrease or If the limit is exceeded, the test can be paused and the film stabilized again to avoid invalid data.

[0135] 4.4 Friction Data Acquisition and Output

[0136] coefficient of friction Calculate as follows:

[0137] ;

[0138] in, It is tangential friction; This is the normal load.

[0139] Typical normal pressure can be (Converted from contact area); sliding speed, reciprocating frequency, or rotational speed are set according to equipment capacity; records are kept. Curves showing changes over time or with slip / velocity, with simultaneous recording of the water film state. , ).

[0140] 4.5 Data Statistics and Repeatability

[0141] Each sample should be tested at least three times, and the mean and standard deviation should be output; repeatability can be assessed using the coefficient of variation (CV); it is recommended to also provide film stability indicators in the report. , , As a quality appendix, it enables traceability.

[0142] V. Examples and Comparative Examples

[0143] (I) Overall Experimental Plan

[0144] 1.1 Experimental Objectives and Evaluation Indicators

[0145] The invention “Epoxy Flooring Wet Test Interface and Construction Method (including stable / limited film)” demonstrates that, compared with existing common interfaces (rough concrete, metal sheet, unpolished epoxy, etc.), it can: 1) form and maintain a continuous and stable thin water film; 2) significantly reduce the dispersion (CV) of wet friction tests; and 3) enhance the distinguishability and sorting consistency between different tread rubber materials.

[0146] 1.2 Main Evaluation Indicators

[0147] 1) Surface roughness: ( ).

[0148] 2) Static contact angle: (°).

[0149] 3) Target film thickness: ( ).

[0150] 4) Film thickness stability: in For the first Secondary sampling membrane thickness For the target film thickness, This represents the number of sampling points.

[0151] 5) Water film coverage: in The effective area is covered by a continuous water film. This represents the total area of ​​the effective zone.

[0152] 6) Stabilization time: (min) refers to satisfying and The continuous holding time.

[0153] 7) Coefficient of friction: in For tangential friction, It is the normal force.

[0154] 8) Small slip zone index (if a small slip device is used): (0.5% slip) (1–3% slip peak) .

[0155] 9) Repeatability: CV (coefficient of variation) .

[0156] 1.3 Equipment and Standardized Testing Conditions

[0157] Friction device: disc-block type wet tribometer (or linear reciprocating tribometer), equipped with normal loading and friction force acquisition;

[0158] Film formation and measurement: atomized spraying + micro-scraper uniform film distribution; film thickness measurement (either laser displacement or dispersive confocal film can be selected); coverage is achieved using industrial camera reflection contrast imaging;

[0159] Sample: Flat plate sample of vulcanized tire tread rubber, dimensions ,thickness Surface polished to ;

[0160] Operating conditions: RH 50–70%; normal pressure Sliding speed Each test lasts 10 minutes; each condition is repeated. .

[0161] 1.4 Tread compound material (used for "discrimination" verification)

[0162] Select 3 typical rubber compound formulations (for comparison only, no restrictions):

[0163] Compound R1: High-silica wet grip formulation (expected to have high wet friction).

[0164] Rubber compound R2: Balanced formulation (medium)

[0165] Rubber compound R3: A more wear-resistant formulation (lower wet friction).

[0166] (II) Implementation Examples and Comparative Examples

[0167] 2.1 Examples (E1–E6)

[0168] Key variables in this invention: window, Window, membrane boundary structure, stable membrane closed loop.

[0169] E1: Polished concrete substrate + epoxy layer ; Enclosure membrane; Closed-loop stabilized membrane; ;

[0170] E2: Polished concrete substrate + epoxy layer ; Capillary membrane confinement groove; Closed-loop stabilized membrane; ;

[0171] E3: Steel plate substrate + epoxy layer polishing. ; Enclosure + capillary groove; closed-loop stabilized film; ;

[0172] E4: Steel plate substrate + epoxy layer polishing. ; Enclosure membrane; Closed-loop stabilized membrane; ;

[0173] E5: Concrete substrate + polished epoxy layer ; Enclosure membrane; Closed-loop stabilized membrane; ;

[0174] E6: Concrete substrate + epoxy layer polishing ; (Slightly hydrophilic); enclosure membrane; closed-loop stabilizing membrane; .

[0175] 2.2 Comparative Examples (C1–C6)

[0176] C1: Unpolished epoxy flooring Unstable membrane closed loop; (name);

[0177] C2: Rough concrete, Difficult to form a film; spray ring opening;

[0178] C3: Polished stainless steel sheet ; Low surface energy / mismatch; no boundary-limited film; open-ring;

[0179] C4: Asphalt board. Unstable water film; open-loop operation;

[0180] C5: Satisfied (0.10) but without surface energy regulation ( (It is slightly hydrophobic), and although there is a barrier, stabilizing the membrane is difficult;

[0181] C6: Satisfied (0.10) and However, without annular membrane boundary structure (no enclosure / no capillary groove), closed-loop stable membrane is still prone to edge dewetting.

[0182] (III) Interface construction parameters and film stabilization performance data

[0183] Table 1 Interface parameters and film stability indicators (n=5)

[0184]

[0185] Note: C2 rough concrete often exhibits "difficulty in forming a continuous film" under film conditions, so RMSE is not listed; C6 shows that "relying solely on closed-loop film control but without a boundary-limited film structure" will result in edge wetting, leading to a decrease in coverage and film stabilization time.

[0186] (iv) Results and repeatability of wet friction test

[0187] The following example uses the friction coefficient under "stable film formation conditions" (same device, same operating conditions; each data point is the mean ± standard deviation of n=5).

[0188] Table 2 shows the wet friction results and repeatability at the E1 interface (in this invention).

[0189]

[0190] Table 3. Results and repeatability of wet friction on the comparative interface

[0191]

[0192] (v) Proof of consistency between material discrimination and sorting

[0193] 5.1 Significance of differences between groups

[0194] In the E1 interface, there are three groups: R1, R2, and R3. The means differ significantly and have high repeatability, so a one-way ANOVA can be performed to obtain... At the C1 interface, the large variance due to the instability of the water film often results in… Value increases, discrimination decreases, or ranking shifts.

[0195] 5.2 Order Consistency ("Order Preservation Rate" in n=5 Repetitions)

[0196] Define "rank retention rate" as the proportion of materials whose ranking remains R1>R2>R3 in 5 repetitions.

[0197] Table 4 Comparison of Sort Retention Rate

[0198]

[0199] (vi) Summary of conclusive technical effects

[0200] 1) Significantly improved film stabilization capability: Examples E1–E6 show that... By matching the wetting window, configuring the membrane boundary structure, and setting a closed-loop control membrane, all of these can be achieved. A continuous water film and maintain min or above, and The comparison samples generally showed film thickness drift, edge de-wetting, or localized dry spots.

[0201] 2) Significantly improved repeatability: On the interface (E1) of this invention, the CV of wet friction results is about 2%; while the CV of comparative examples such as unpolished epoxy (C1) and metal sheet (C3) is often 5-10%.

[0202] 3) Improved material differentiation and sorting consistency: The material sorting retention rate on the interface of this invention reaches 100%, which can stably distinguish different formulations; the interface of the comparative example is prone to sorting drift due to uncontrollable wet boundary conditions.

[0203] The foregoing description of embodiments of the present invention, through which those skilled in the art are able to implement or use the present invention, will be readily apparent to those skilled in the art. Various modifications to these embodiments will be readily apparent to those skilled in the art. The general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novelty disclosed herein.

Claims

1. An epoxy flooring wet testing interface for tire wet performance testing, characterized in that, It includes a substrate layer and an epoxy flooring layer disposed on the surface of the substrate layer; The epoxy flooring layer is formed by coating and curing a two-component or multi-component epoxy resin system. After curing, it is ground or polished in stages to make its surface roughness Ra 0.05 to 1.0 μm. The outer surface of the epoxy floor layer has a surface energy parameter to match the wet film-forming characteristics of the epoxy floor, and the surface energy is expressed as surface free energy γ, which is 25 to 45 mN / m. During the test, a continuous water film is formed on the surface of the epoxy floor layer. The thickness of the continuous water film is 10-300 μm, and the continuous water film meets the following verifiable criteria: within the preset effective test area, the water film coverage Cw ≥ 0.95, and Cw is maintained at no less than 0.90 for a continuous test time of no less than 6 minutes. Wherein, the water film coverage rate Cw is the ratio of the area continuously covered by the water film in the effective test area to the total area of ​​the effective test area, and the coverage area is determined by any one of optical imaging reflection contrast, laser speckle imaging or capacitance array measurement; and the test interface is provided with an annular limiting film boundary structure along the circumference to suppress water film edge retreat and local dry spot formation, so as to improve the repeatability of wet test conditions.

2. The test interface according to claim 1, characterized in that, The annular membrane-limiting boundary structure is: a circumferential enclosure, a circumferential capillary membrane-limiting groove, or a combination of an enclosure and a capillary membrane-limiting groove, wherein the width of the capillary membrane-limiting groove is 0.2 to 2.0 mm and the depth is 0.1 to 1.5 mm. And / or, the thickness uniformity of the continuous water film satisfies the following: the difference between the maximum and minimum values ​​of the water film thickness within the effective test area is not greater than ±20% of the set value of the water film thickness.

3. The test interface according to claim 1, characterized in that, The surface free energy γ is achieved by introducing a surface energy regulation layer on the surface of the epoxy floor layer. The surface energy regulation layer is a hydrophilic modification layer, a weakly hydrophobic modification layer, or a gradient composite layer of both. And / or, the substrate layer is any one of a concrete slab, a steel plate or a stainless steel plate, and a primer layer is provided between the substrate layer and the epoxy floor layer to improve adhesion and water immersion stability.

4. The test interface according to claim 1, characterized in that, The surface macroscopic tilt angle of the effective test area is 0 to 1°, in order to cooperate with the annular membrane boundary structure to maintain a continuous water film.

5. A method for constructing the test interface according to any one of claims 1 to 4, characterized in that, include: S1. Provide a substrate layer and perform surface treatment; S2. Apply and cure the epoxy resin system to form an epoxy floor layer; S3. Grind or polish the epoxy flooring surface step by step to achieve a surface roughness Ra of 0.05–1.0 μm; S4. Perform surface energy regulation treatment on the outer surface of the epoxy floor layer to make the surface free energy γ 25~45 mN / m; S5. A ring-shaped membrane boundary structure is formed circumferentially on the test interface; S6. Before testing, water is distributed to form a continuous water film, and the film formation state is calibrated by the coverage rate Cw and / or the uniformity of the water film thickness to ensure that the continuous water film meets the criteria.

6. The construction method according to claim 5, characterized in that, The surface energy modulation treatment in step S4 includes any one or more of plasma treatment, hydrophilic agent coating and curing, or weak hydrophobic agent coating and curing, to control the static water contact angle between 20° and 80°.

7. The construction method according to claim 5, characterized in that, In step S6, a continuous water film is formed by spraying water and using a uniform film distribution component. The uniform film distribution component is any one of a scraper strip, a roller pressing uniform film distribution roller, or an air knife uniform film distribution device. And / or, in step S6, the water film coverage Cw is obtained by optical imaging reflection comparison or capacitance array measurement, and the spray flow rate, spray frequency and / or pressure of the uniform film component are adjusted with Cw as feedback parameter to achieve water film continuity closed-loop calibration.

8. A wet testing system for epoxy flooring used for tire wet performance testing, characterized in that, include: A test interface installation platform for installing any of the test interfaces described in claims 1 to 4; Water distribution assembly is used to supply water to the test interface to form a continuous water film; Film formation monitoring component for obtaining water film coverage Cw and / or water film thickness uniformity; A control component, connected to the water distribution component and the film formation monitoring component, is used to adjust the water supply parameters according to Cw and / or the uniformity of the water film thickness, so that the continuous water film meets the criterion described in claim 1. Friction / grip testing kit is used to test the wet friction performance of tires, tread rubber samples or rubber materials under continuous water film conditions and output test data.

9. The testing system according to claim 8, characterized in that, The film formation monitoring component is any one or more of an optical imaging module, a laser measurement module, or a capacitor array module; the control component adjusts the water supply parameters by at least any one or more of the following: water supply flow rate, water supply pressure, spray frequency, and pressure of the uniform film component.

10. A method for testing the wet performance of tires using the testing system described in claim 8 or 9, characterized in that, include: M1. Install the test interface and start the water distribution assembly to form a continuous water film; M2. Obtain water film coverage Cw and / or water film thickness uniformity through film formation monitoring components; M3. After the water supply parameters are adjusted in a closed loop by the control component to make the continuous water film meet the criteria, the test phase begins. M4. Perform friction / grip test under continuous water film conditions that meet the criteria and output wet performance evaluation index.

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