A high water-absorbing polyurethane foam for a mop and a method for preparing the same

Abstract

The present application relates to the technical field of molecular porous materials, and discloses a high-water-absorption polyurethane foam material for a mop and a preparation method thereof. The present application introduces a hydrophilic system and constructs a dynamic mixed crosslinking network through molecular structure design, so that the material has a specific gradient porous structure. With the aid of the porous structure, rapid water permeation and efficient water storage can be realized, and the water absorption rate and speed are improved. Through the synergistic effect of a composite polyol system and a crosslinking agent, the high tensile strength of the material is ensured, and the phenomena of extrusion deformation and chipping are avoided. At the same time, the uniform high-open-structure effectively reduces stain residues and plays an antibacterial function. The present application effectively solves the problem that the existing polyurethane foam material for a mop cannot simultaneously have high water absorption performance and good mechanical strength, and the foaming forming process is stable and controllable, and is suitable for industrialized mass production.

Description

Technical Field

[0001] This invention relates to the field of molecular porous materials technology, and more specifically, to a high water absorption polyurethane foam material for mops and its preparation method. Background Technology

[0002] As an indispensable tool in daily cleaning, the performance of the sponge head, the core cleaning component of a mop, determines its cleaning efficiency and user experience. Polyurethane foam, due to its excellent softness and water absorption potential, is currently the most widely used core material for mop heads on the market. In actual cleaning scenarios, users often expect the mop material to quickly absorb water from the floor and have sufficient water storage space to reduce the number of rinses, thereby improving the efficiency of cleaning large areas.

[0003] Currently, commercially available polyurethane foam for mops generally suffers from a trade-off between high absorbency and durability. Conventional polyurethane foam typically absorbs 4-5 times its own weight in water, requiring multiple applications of water during cleaning, leading to low efficiency. Furthermore, existing materials often exhibit overly large pore sizes, high closed-cell ratios, or uneven open-cell structures, resulting in slow water penetration and an inability to quickly handle large water stains. While current technologies attempt to increase absorbency by adding hydrophilic groups, this can reduce the foam's mechanical strength, causing deformation, breakage, and shedding after repeated use, shortening its lifespan. Conversely, increasing the open-cell ratio weakens the foam's water retention capacity, leading to moisture loss. Moreover, the existing irregular pore structure easily leaves residue after cleaning, fostering bacterial growth and compromising daily hygiene. Therefore, there is an urgent need to develop a polyurethane foam material for mops that balances high absorbency, rapid water absorption, and good mechanical stability. Summary of the Invention

[0004] In view of the aforementioned existing problems, the present invention is proposed.

[0005] Therefore, the present invention provides a high water absorption polyurethane foam material for mops and its preparation method, solving the technical problem that existing polyurethane foams for mops cannot achieve both high cleaning efficiency and good durability.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: This invention provides a method for preparing a high-absorbency polyurethane foam material for mops, comprising the following steps: S1. By weight, 50-60 parts of hydrophilic polyether polyol, 25-35 parts of soft polyether polyol, 1-3 parts of trimethylolpropane, 0.5-1.5 parts of a compound chain extender composed of 1,4-butanediol and diethanolamine in a mass ratio of 1:0.8-1.2, and functional additives are stirred at 50-60 °C for 30-40 min to obtain a premixed solution; S2. Add 1-1.5 parts of deionized water and 1.5-2.5 parts of polysiloxane-polyether copolymer to the premixed liquid, and perform high shear treatment at a high shear speed of 800-1000 r / min for 10-15 min to obtain an emulsion; S3. Lower the system temperature, add 0.3-0.7 parts of a compound gel catalyst composed of triethylenediamine and dibutyltin dilaurate in a mass ratio of 1:0.5-0.8 to the emulsion and mix well; then inject 50-60 parts of diphenylmethane diisocyanate and stir at high speed at 1300-1400 r / min for 20-30 s to obtain a foamed mixture; S4. Pour the foaming mixture into a preheated mold within 5-8 seconds and let it stand to foam. After initial gelation and shaping, perform high-temperature curing, cool and demold to obtain the finished product.

[0007] As a preferred embodiment of the method for preparing high water absorption polyurethane foam material for mops according to the present invention, in step S1, the amount of hydrophilic polyether polyol added is 55 parts, the amount of soft polyether polyol added is 30 parts, the amount of trimethylolpropane added is 2 parts, and the amount of compound chain extender added is 1 part.

[0008] As a preferred embodiment of the method for preparing high water absorption polyurethane foam material for mops according to the present invention, in step S1, the functional additives include 0.3 parts of antibacterial agent silver-loaded zirconium phosphate and 0.5 parts of liquid antioxidant Irganox 1135; the stirring parameters are: stirring at 55°C for 35 min.

[0009] In a preferred embodiment of the method for preparing high water absorption polyurethane foam material for mops according to the present invention, in step S2, the amount of deionized water added is 1.2 parts and the amount of polysiloxane-polyether copolymer added is 2 parts.

[0010] In a preferred embodiment of the method for preparing high water absorption polyurethane foam material for mops according to the present invention, in step S2, the high shear speed is 900 r / min and the high shear time is 12 min.

[0011] As a preferred embodiment of the method for preparing high water absorption polyurethane foam material for mops according to the present invention, in step S3, the amount of the compound gel catalyst added is 0.5 parts, and the amount of the diphenylmethane diisocyanate added is 50.5 parts; the high-speed stirring parameters are 1350 r / min for 24 s.

[0012] In a preferred embodiment of the method for preparing high-absorbency polyurethane foam material for mops according to the present invention, wherein: in step S4, the static foaming process is as follows: Using an automatic pouring machine, the foaming mixture is poured into a mold preheated to 45°C within 5-8 seconds, and allowed to stand at 45°C for 20 minutes to complete stable foaming and initial gel setting.

[0013] In a preferred embodiment of the method for preparing the high water absorption polyurethane foam material for mops according to the present invention, wherein: in step S4, the high-temperature curing process is as follows: After the material has completed the initial gelation and shaping, it is sent into an industrial curing tunnel at 80°C for continuous curing for 2.5 hours to achieve deep curing of the cross-linked network.

[0014] In a preferred embodiment of the method for preparing the high water absorption polyurethane foam material for mops according to the present invention, wherein: in step S4, the cooling and demolding process is as follows: After curing, the finished product is removed from the tunnel and allowed to cool naturally to room temperature. It is then removed using an automatic demolding device to obtain high water absorption polyurethane foam.

[0015] This invention also provides a high water absorption polyurethane foam material for mops, prepared by the above method, wherein: the polyurethane foam material has a three-dimensional, fully open-cell network structure; its internal flexible main skeleton is a continuous solid-phase membrane constructed by deep cross-linking of the hydrophilic polyether polyol and the soft polyether polyol composite substrate with the diphenylmethane diisocyanate; a hydrophilic film constructed by the directional extension of the polysiloxane-polyether copolymer seamlessly covers the pore wall surface of the solid-phase membrane; the silver-loaded zirconium phosphate inorganic particles are uniformly embedded and anchored in the cross-linking nodes of the solid-phase membrane, and the solid-phase membranes are spatially interwoven to form a continuous, interconnected capillary water-retaining pore structure.

[0016] The beneficial effects of this invention are as follows: by designing the molecular structure and constructing a dynamic mixed cross-linking network, the technical problem of existing polyurethane foam for mops being unable to simultaneously achieve high water absorption and good mechanical strength is effectively solved.

[0017] Specifically, in terms of cleaning performance, the unique gradient porous structure combined with a hydrophilic system allows the foam to quickly penetrate and absorb surface water through large surface pores, while the internal micropores provide a large water storage space, improving the overall water absorption rate and speed. In terms of durability, the composite polyol system and crosslinking agent work synergistically to ensure the foam's high tensile strength, avoiding deformation and shedding defects caused by repeated daily compression. In terms of hygiene and processing, the uniform cell structure with a pore size of 50~100 μm and an open cell rate of ≥90% reduces stain residue to achieve an antibacterial effect, while the controllable gel foaming rate avoids foam collapse and pinhole problems, ensuring the stability of industrial mass production. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 Figure 1 shows the results of optimizing the amount of polyol base added.

[0020] Figure 2 Figure 2 shows the results of optimizing the amount of polyol base added.

[0021] Figure 3 One of the results of optimizing the addition amount of TMP and BDO / DEA.

[0022] Figure 4 Figure 2 shows the results of optimizing the addition of TMP and BDO / DEA.

[0023] Figure 5 The figure shows the results of optimizing the addition amount of polysiloxane-polyether copolymer.

[0024] Figure 6 The figure shows the results of optimizing the addition of triethylenediamine / dibutyltin dilaurate.

[0025] Figure 7 One of the figures shows the optimization results of high shear speed and shear time.

[0026] Figure 8 The second figure shows the optimization results of high shear speed and shear time.

[0027] Figure 9 The result is shown in the figure for optimizing the high-speed stirring time.

[0028] Figure 10 This is a structural diagram of a high-absorption polyurethane foam material for mops.

[0029] Figure 11 This is a flowchart illustrating a method for preparing a high-absorption polyurethane foam material for mops. Detailed Implementation

[0030] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0031] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0032] Secondly, the term "one embodiment" or "example" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the invention. The appearance of an embodiment in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that mutually excludes other embodiments.

[0033] In polyurethane foam systems, to meet the strength requirements of the basic skeleton in high-absorbency mop foam materials, this invention regulates the crosslinking network density through the isocyanate index. The amount of foaming agent (deionized water) added is limited to 1.0~1.5 parts by weight; the diphenylmethane diisocyanate (MDI) used is a liquefied modified MDI (average functionality... The NCO mass fraction is limited to 29-31%. The specific amount of MDI added is not a fixed constant, but is dynamically calculated based on the hydroxyl / amino active hydrogen equivalent of each raw material in the formulation system of this invention. This ensures that when the composition of each component fluctuates, the overall isocyanate index of the system is controlled within the range of 1-1.1 (preferably 1.05), thereby ensuring the consistency of the strength of the cross-linked solid skeleton.

[0034] Example 1 This embodiment provides a raw material formulation system for a high water absorption polyurethane foam material for mops, solving the technical problem that existing polyurethane foams for mops cannot simultaneously achieve high cleaning efficiency and good durability.

[0035] 1.1 Screening of polyol matrix materials In polyurethane foam systems for mops, the polyol matrix is ​​the cornerstone of the polymer skeleton of the foam material, determining the finished product's water absorption and retention performance as well as its mechanical tensile properties. It needs to possess good hydrophilic permeability and elastic recovery potential, but this synergistic effect cannot be achieved with a single polyol. Therefore, it is necessary to composite different polyols with complementary physicochemical structures to neutralize the performance deficiencies of individual materials. While ensuring the compatibility of the polymerization reaction and the system, this composite achieves both rapid water absorption and the ability to withstand repeated physical deformation from daily compression. This provides a reliable polymer skeleton carrier for the stable molding of the porous structure of the overall foam material and the synergistic effect of its water absorption and tensile properties.

[0036] Four representative types of basic polyols in the polyurethane foaming field were selected for compounding. Each binary polyol (premixed at a 1:1 mass ratio) was used as a basic skeleton component, and compounding ratios were performed in a basic reference system at fixed addition amounts: hydrophilic polyether polyol / conventional polyester polyol; flexible polyether polyol / conventional polyester polyol; hydrophilic polyether polyol / polymer polyol; flexible polyether polyol / polymer polyol; and hydrophilic polyether polyol / flexible polyether polyol. The compounding effect was determined by testing the uniformity of the formed cell structure, saturated water absorption rate, wet tear strength, and repeated extrusion breakage rate.

[0037] Cell uniformity: The foam material sample after foaming and maturation was cut along the cross-section and surface-sprayed with gold. Microscopic morphology images were acquired using a scanning electron microscope. Image processing software was used to statistically analyze the variance of pore size distribution per unit area and the proportion of pores with a diameter of 50–100 μm. This value characterizes the emulsification and dispersion state of the gas-liquid two phases and the stability of the skeletal structure formation during the foaming process. The smaller the variance of pore size distribution and the higher the proportion of the target pore size, the more uniform and stable the microscopic channels are provided for rapid water penetration.

[0038] Saturated water absorption rate: Foam material samples dried to constant weight were cut into standard dimensions of 50 mm × 50 mm × 50 mm, and their initial dry weight was recorded. They were then immersed in deionized water at 25°C until saturated. After removing the samples and allowing free surface water to drip off, their wet weight was measured. The ratio of the mass difference before and after water absorption to the initial dry weight was calculated. This value reflects the adsorption capacity of the hydrophilic segments within the foam material and the water storage capacity of its gradient porous structure. A higher water absorption rate indicates stronger water penetration and retention efficiency of the substrate material, resulting in better macroscopic cleaning performance of the finished product.

[0039] Wet tear strength: The foam material is cut into standard specimen strips of 150 mm × 25 mm × 25 mm (with a 40 mm slit pre-made at one end along the center line), and soaked until saturated with water. Then, both ends of the slit are clamped in the upper and lower fixtures of a computer-controlled universal testing machine for axial traction, and the maximum load force at which the specimen tears is measured. This value reflects the molecular chain entanglement strength and stress resistance of the polyurethane polymer backbone under the swelling effect of water molecules. The higher the wet tear strength, the less likely it is to crack or physically break under dragging friction conditions.

[0040] Repeated compression breakage rate: The initial dry weight of foam material blocks cut into standard sizes of 100 mm × 100 mm × 50 mm was weighed, placed in the test chamber of a dynamic fatigue testing machine for foam, and filled with water. Continuous alternating compression cycles were performed under 75% compression deformation. The detached fragments were collected after the test, dried, and the percentage of mass loss was calculated. This value characterizes the dynamic elastic deformation recovery ability of the porous skeleton of the foam material and the fatigue resistance of the micro-crosslinked network. The lower the breakage rate, the less likely it is to experience chipping and structural collapse during dehydration and compression operations.

[0041] The results are shown in Table 1: Table 1. Screening results of polyol matrix materials Among them, hydrophilic polyether polyols / polymer polyols have high saturated water absorption rates, but their wet tear strength is low, making them prone to cracking and breakage; conventional polyester polyols / soft polyether polyols have low repeated extrusion breakage rates, but their saturated water absorption rates are low, resulting in weak water penetration and retention efficiency. Therefore, hydrophilic polyether polyols / soft polyether polyols, which offer better overall performance, are selected as the polyol base. To ensure the stable reproduction of the above synergistic effects in actual production, this scheme further limits the microscopic physicochemical parameters of the two components in the composite framework: the hydrophilic polyether polyol has a hydroxyl value of 110~130 mgKOH / g, a molecular weight of 2000~3000, and contains 5~8wt% ethylene oxide hydrophilic segments; the soft polyether polyol is a homopolymer of propylene oxide, with a hydroxyl value of 56~62 mgKOH / g and a molecular weight of 3000~4000.

[0042] 1.2 Screening of isocyanate components In polyurethane foam systems, the microscopic polymer cross-linking network is mainly constructed by the polymerization reaction of hydroxyl groups in polyols and isocyanate groups in isocyanates. Given a composite polyol matrix, isocyanate, as the core reactant, determines the final cross-linking density of the foam material skeleton through its reactivity and molecular configuration, thus affecting its macroscopic mechanical properties such as tear resistance and compression resistance. Therefore, it is essential to screen the isocyanate component to ensure that the polymer skeleton possesses structural support after curing.

[0043] After fixing the composite polyol substrate, the candidate isocyanate components were mixed and foamed according to the same isocyanate index: toluene diisocyanate (TDI-80), toluene diisocyanate (TDI-65), poly(diphenylmethane) diisocyanate (PMDI), diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), and 1,5-naphthalene diisocyanate (NDI). The micro-crosslinking and curing effect were determined by detecting the foaming gel time, 25% compression support hardness, wet tear strength, and repeated extrusion breakage rate of each group of foamed samples.

[0044] Foaming and gelation time: After mixing the composite polyol base with each isocyanate component at 25°C with high-speed stirring, the mixture is poured into an open foaming container. The time required from the start of material mixing until the viscosity of the reaction system changes abruptly and stringing occurs on the surface of the foam is recorded. This value reflects the curing rate of the micro-crosslinking polymerization reaction between isocyanate and polyol.

[0045] 25% Compression Support Hardness: Cured foam material was cut into 50 mm × 50 mm × 50 mm cubic specimens and placed on the lower bearing plate of a computer-controlled universal testing machine. The upper pressure plate was controlled to press vertically down on the specimen at a rate of 50 mm / min. The bearing capacity generated when the specimen was compressed to 25% of its initial thickness was measured. This value reflects the density of hard segment micro-regions formed by isocyanate aggregation and the overall rigid framework support force of the macromolecular three-dimensional cross-linked network in the polyurethane microphase separation structure.

[0046] The results are shown in Table 2: Table 2 Screening results of isocyanate components Among them, PMDI has good 25% compression set hardness, but its repeated compression breakage rate is high, making it prone to micro-fracture and breakage of the foam material; NDI has high wet tear strength, but its foaming gel time is short, making it prone to burst polymerization. Therefore, diphenylmethane diisocyanate, which has better overall performance, was selected as the isocyanate component, with an NCO content of 29-31%.

[0047] 1.3 Screening of crosslinking agents While the aforementioned polyurethane framework already possesses good water absorption and compression resistance, it contains a large number of hydrophilic segments. Once saturated with water, the foam material is prone to excessive swelling in the wet state, leading to softening and deterioration of the framework, thus reducing the scrubbing force required for mopping. Therefore, a crosslinking agent is introduced to resist the swelling effect of water molecules, thereby locking in the wet dimensional stability and structural strength of the foam material.

[0048] The aforementioned preferred hydrophilic / soft composite polyether polyol substrate, conventional chain extender, and auxiliary agents were fixed as the base raw materials. Equal amounts of each crosslinking agent were added: ethylene glycol (EG), 1,4-butanediol (BDO), diethanolamine (DEA), triethanolamine (TEA), glycerol, and trimethylolpropane (TMP). The mixture was heated and stirred until homogeneous to obtain a premix. Deionized water and a foaming agent were then added for emulsification, followed by the addition of a gel catalyst and mixing until homogeneous. Finally, MDI was added and stirred at high speed. When the system began to expand, it was poured into a mold. After foaming, gelling, and heating for curing, the foam material sample was obtained by cooling and demolding. The wet volume swelling rate, wet hardness retention rate, and apparent open cell ratio were tested to determine the microscopic anchoring effect and wet stability of each crosslinking agent.

[0049] Wet volume swelling ratio: The cured foam material was cut into standard 50 mm × 50 mm × 50 mm samples. The initial apparent volume was measured and calculated using high-precision vernier calipers. The samples were then immersed in deionized water at 25°C for 24 hours until saturation. After removing the samples and wiping away surface water with absorbent filter paper, the wet volume was measured again, and the percentage increase in volume before and after immersion was calculated. This value characterizes the anchoring ability of the crosslinking agent. The smaller the wet volume swelling ratio, the less likely the material is to become porous, rotten, or structurally loose.

[0050] Wet hardness retention rate: The foam material was cut into standard blocks of 50 mm × 50 mm × 50 mm. First, its 25% compressive strength under oven-dry conditions was measured using a computer-controlled universal testing machine. Then, it was fully saturated with water, and its wet 25% compressive strength was measured under the same test parameters. The ratio of wet hardness to dry hardness was calculated. A higher wet hardness retention rate indicates that the foam material can better maintain the underlying scraping strength required to clean stubborn stains on the floor.

[0051] Apparent open porosity: The foam material is punched into standard cylindrical samples, and high-purity nitrogen gas at a test pressure of 20 kPa is injected at 25°C using a fully automated true density meter to measure the volume of the displaced skeletal structure. Combined with the apparent geometric volume of the sample, the proportion of interconnected open pore volume within the sample is calculated. This value characterizes the degree of polyurethane bubble wall rupture and three-dimensional micro-capillary channel interconnection at the end of the foaming reaction. A higher apparent open porosity indicates a better promoting effect on foaming gas degassing and cell interconnection, and a more complete interconnected capillary network is constructed.

[0052] The results are shown in Table 3: Table 3. Screening results of crosslinking agents As shown in the table, TEA has a low wet volume swelling ratio, but its apparent porosity is small, which easily leads to blockage of the water absorption channels; BDO ​​has a large apparent porosity, but its wet hardness retention rate is low, its bottom layer has insufficient scraping strength, and it is prone to decay. Therefore, pure trimethylolpropane (TMP), which has a better overall effect, was selected as the crosslinking agent of this invention, with a theoretical hydroxyl value of approximately 1254 mgKOH / g.

[0053] 1.4 Screening of chain extenders The same pretreatment, emulsification, catalytic foaming, and molding curing processes as described above were employed. Using a fixed, preferred hydrophilic / soft composite polyether polyol base and TMP and other basic raw materials, four common chain extenders were selected and compounded in pairs, added in equal amounts to the aforementioned system: 1,4-butanediol (BDO) / ethylenediamine (EDA), 1,4-butanediol (BDO) / diethanolamine (DEA), 1,4-butanediol (BDO) / diethylene glycol (DEG), ethylenediamine (EDA) / diethanolamine (DEA), ethylenediamine (EDA) / diethylene glycol (DEG), and diethanolamine (DEA) / diethylene glycol (DEG). After forming a foamed mixture, it was injected into a mold. The wet tear strength, repeated compression breakage rate, and wet hardness retention rate of each group were tested to determine their synergistic toughening effect.

[0054] The results are shown in Table 4: Table 4. Results of chain extender screening As shown in the table, BDO / EDA exhibits high wet tear strength, but its repeated compression breakage rate is also high, making the foam material prone to brittle fracture during repeated compression and dehydration. BDO / DEG, on the other hand, has a lower repeated compression breakage rate, but its wet hardness retention is low, resulting in insufficient scraping force for cleaning floors. Therefore, BDO / DEA, with its better overall performance, was selected as the chain extender in this invention, with a mass ratio of 1:0.8~1.2.

[0055] 1.5 Screening of foaming agents To achieve rapid absorption and reduce stain residue, the foam leveling agent in the foaming system was qualitatively screened. As a surface tension regulator and emulsifying dispersant, the selected foam leveling agent not only needs to maintain the stability of the bubble structure during the foaming process to prevent collapse, but also needs to promote the breaking and opening of micropores at the end of the molding process, thereby reducing the closed-cell problem caused by traditional hydrophobic silicone oil or the large-area bubble collapse caused by hydrophilic surfactants.

[0056] A premix containing a composite polyether polyol base, TMP, and BDO / DEA was pre-prepared in a stirred tank. During the continuous emulsification stage, various foaming agents were added to the premix: low HLB value polydimethylsiloxane (HLB 4-6), medium-low HLB value polysiloxane-polyether copolymer (HLB 8-10), polysiloxane-polyether copolymer (HLB 12-15), high HLB value polysiloxane-polyether copolymer (HLB 16-18), ultra-high HLB value polyoxyethylene-polyoxypropylene copolymer (HLB 19-22), and perfluoroalkyl ethoxy alcohol (HLB 10-13). Each system was mixed with deionized water, catalyst, and MDI via a standard mixing pipeline. After foaming and curing by injection molding through a high-speed mixing head, samples of each batch of finished product were taken to test their surface droplet penetration time, molding volume collapse rate, and apparent open porosity.

[0057] Surface droplet penetration time: A standard cube of foam material (50 mm × 50 mm × 20 mm) was cut and placed on a horizontal test platform. A 0.1 mL droplet of deionized water was added to the center of the sample surface using a micropipette, and the timing was recorded. Timing was stopped when the droplet penetrated into the foam material and the surface exhibited a non-mirror-reflective wetted state. This value characterizes the initial wettability of the material surface and the capillary absorption rate. A shorter surface droplet penetration time indicates a better improvement in hydrophilic enrichment of the material surface.

[0058] Molding volume collapse rate: After foaming and curing in the mold, the nominal geometric volume of the mold cavity is measured before demolding. After the foam material cools naturally to room temperature, the actual apparent geometric volume of the demolded product is measured using a three-dimensional dimensional measuring instrument. The volume collapse rate is calculated by the ratio of the volume difference to the nominal geometric volume. The smaller the molding volume collapse rate, the more effectively macroscopic shrinkage and structural collapse can be reduced.

[0059] The results are shown in Table 5: Table 5. Screening Results of Foaming Agents Among them, low HLB value polydimethylsiloxane has a good molding volume collapse rate, but its apparent open cell ratio is low, which cannot meet the rapid absorption requirements of mop foam materials; ultra-high HLB value polyoxyethylene-polyoxypropylene copolymer has a high apparent open cell ratio, but its molding volume collapse rate is large, resulting in greater structural damage to the finished product. Therefore, polysiloxane-polyether copolymer (HLB 12-15), which has a better overall performance, was selected as the foam leveling agent.

[0060] 1.6 Screening of Gel Catalysts After preparing the premix and emulsion as described above, four common polyurethane catalysts were selected and compounded in pairs, and added in equal amounts to the above system: ethylenediamine / dimethylbenzylamine, ethylenediamine / stannous isooctanoate, ethylenediamine / dibutyltin dilaurate, dimethylbenzylamine / stannous isooctanoate, dimethylbenzylamine / dibutyltin dilaurate, and stannous isooctanoate / dibutyltin dilaurate. Each system was mixed with MDI to form a foaming mixture, which was then injected into a mold and cured. The apparent density of the molded core, the curing closed-cell shrinkage rate, and the internal structural defect rate of each group were tested to determine their synergistic matching effect on the gel and foaming reaction rates.

[0061] Apparent density of the molded core: After removing the molded skin layer from the surface of the foam material product, a 100 mm × 100 mm × 50 mm cuboid sample was cut from the core. After being conditioned at 23°C and 50% RH, its mass was weighed using a high-precision balance, and its geometric dimensions were measured using vernier calipers to calculate its volume. The mass-to-volume ratio was then obtained. This value characterizes the actual degree of gas expansion within the foaming system. The lower the apparent density of the core, the stronger the initial gas production expansion motive force of the catalyst.

[0062] Curing closed-cell shrinkage rate: This is calculated by measuring the nominal internal geometric volume of the mold cavity before foaming. After injection molding, foaming, and demolding, the foam material product is placed in a room temperature environment for 24 hours to cool and cure. The actual apparent geometric volume of the cured product is then measured using a 3D dimension scanner. The curing closed-cell shrinkage rate is calculated using the ratio of the difference in geometric volume to the internal geometric volume. A smaller curing closed-cell shrinkage rate reduces the negative pressure deformation caused by premature cross-linking.

[0063] Internal structural defect rate: The foam material product is cut open from the center along a direction perpendicular to the foaming expansion to obtain a flat internal cross-section. A transparent mesh plate with a 1 mm × 1 mm grid is placed over the cross-section, and the sum of the areas occupied by pinholes, hidden cracks, and local collapse voids is calculated as a percentage of the total cross-sectional area. This value characterizes the degree of gas escape and local structural damage during the foaming process.

[0064] The results are shown in Table 6: Table 6. Screening results of gel catalysts Among them, triethylenediamine / dimethylbenzylamine has a lower curing closed-cell shrinkage rate, but its internal structural defect rate is relatively high, which easily causes internal tearing and flaking of the foam material in the early stage of use; stannous isooctanoate / dibutyltin dilaurate has a lower internal structural defect rate, but its molded core apparent density is relatively high, which will reduce the high resilience and flexibility of the foam material. Therefore, triethylenediamine / dibutyltin dilaurate (mass ratio 1:0.5~0.8) with better overall performance was selected as the gel catalyst.

[0065] Example 2 Reference Figures 1 to 6 This is the second embodiment of the present invention. After clarifying the synergistic effect mechanism of each core component in terms of foam stabilization, cell opening, and reaction kinetics, determining their quantitative proportions in the polyurethane foaming system is a crucial prerequisite for achieving high open-cell ratio and dimensional stability. Therefore, based on the material basis established by the aforementioned screening experiments, this embodiment further explores the optimal addition range of each component, aiming to obtain a preferred process formulation that balances macroscopic structural stability and microscopic capillary liquid absorption efficiency.

[0066] 2.1 Optimization of Polyol Base Addition Amount The synergistic effect of highly hydrophilic units and highly elastic segments in the polyurethane backbone is determined by both hydrophilic polyether polyols and flexible polyether polyols. Excessive addition of hydrophilic polyether, while increasing water absorption, can reduce the mechanical strength of the foam material, making it prone to deformation and breakage under repeated extrusion. Conversely, excessive addition of flexible polyether, while enhancing the structural stability and tensile strength of the foam material, can lead to a decrease in macroscopic water absorption and rapid penetration. Therefore, the dosage of both must be quantitatively optimized to balance water absorption and mechanical stability.

[0067] The amount of hydrophilic polyether polyol added ranged from 35 to 70 parts by weight, with increments of 5 parts by weight in the variable group; the amount of soft polyether polyol added ranged from 50 to 15 parts by weight, with increments of 5 parts by weight in the variable group. Experimental groups were set up by cross-variables, and the process effects of different addition amounts were evaluated by saturated water absorption ratio, wet tear strength, and repeated extrusion breakage rate.

[0068] The results are as follows Figure 1 , 2 As shown, with the increase of hydrophilic polyether polyol addition and the decrease of soft polyether polyol addition, the saturated water absorption rate and repeated extrusion breakage rate increase, while the wet tear strength gradually decreases. To achieve a balance between high water absorption and high mechanical strength, a nonlinear fitting was performed on the intersection point of the optimal gain effect between saturated water absorption rate and wet tear strength, which was found to be located at (54.84, 30.21), where the repeated extrusion breakage rate is relatively low. Based on the batching precision of industrial continuous production, the final selection was 55 parts of hydrophilic polyether polyol and 30 parts of soft polyether polyol addition.

[0069] 2.2 Optimization of TMP and BDO / DEA Addition Amounts The amount of TMP added ranged from 1 to 3 parts by weight, with increments of 0.5 parts by weight. The amount of BDO / DEA added ranged from 2 to 0 parts by weight, with increments of 0.5 parts by weight. These were added together with 55 parts of hydrophilic polyether and 30 parts of soft polyether to a stirred tank to prepare a premix. After catalytic foaming and curing and demolding, the wet tear strength, repeated compression breakage rate and saturated water absorption rate of each sample group were tested.

[0070] The results are as follows Figure 3 , 4 As shown, with the increase of TMP addition and the decrease of BDO / DEA addition, the wet tear strength of the system shows a trend of first increasing and then decreasing, the repeated extrusion breakage rate shows a trend of first decreasing and then increasing, and the saturated water absorption rate shows a monotonically decreasing trend. Nonlinear curve fitting was performed on the golden window (750~900%) of efficient water storage and flexibility of saturated water absorption rate to obtain a safe range. Within this range, the maximum gain effect of wet tear strength and repeated extrusion breakage rate was fitted, and the maximum value of wet tear strength was found at (1.94 parts, 1.06 parts), and the minimum value of repeated extrusion breakage rate was found at (2.08 parts, 0.92 parts). To achieve a balance between the openness of the water storage space and the fatigue life of high-frequency extrusion, the average value (2.01 parts, 0.99 parts) was taken as the theoretical optimal point. Based on the industrial-scale feed ratio accuracy, the final addition amount of trimethylolpropane (TMP) was determined to be 2.0 parts, and the addition amount of BDO / DEA was determined to be 1 part.

[0071] 2.3 Optimization of the amount of polysiloxane-polyether copolymer added A premix was prepared by mixing 55 parts of hydrophilic polyether polyol, 30 parts of soft polyether polyol, 2 parts of TMP, and 1 part of BDO / DEA. Then, 1.2 parts of deionized water were added. Five experimental groups were set up to prepare emulsions by adding polysiloxane-polyether copolymers in increments of 0.5 parts by weight, ranging from 1 to 3 parts by weight. Subsequently, 0.5 parts of triethylenediamine / dibutyltin dilaurate were added, and 50.5 parts of MDI were added based on the total amount of active hydrogen in the system. After rapid stirring and foaming, polyurethane foam material samples were obtained by constant temperature curing and demolding in a mold. The process effect of different foam stabilizer addition amounts was evaluated by detecting the apparent open porosity, surface droplet penetration time, and apparent density of the molded core.

[0072] The results are as follows Figure 5As shown, with the increase of polysiloxane-polyether copolymer addition, the apparent open cell ratio first increases and then decreases, the surface droplet penetration time first decreases and then increases, and the apparent density of the molded core continuously decreases. A function fitting was performed to find the optimal foaming state (28~35 kg / m³) for the apparent density of the molded core, balancing bulkiness and mechanical strength. The calculated safe addition range for this density is between 1.18 and 2.49 parts. Within this safe range, a quadratic polynomial fitting was performed to find the maximum effective gain effect of apparent open cell ratio and surface droplet penetration time. The fitting function is as follows: Apparent Open Cell Ratio Function (goodness of fit) The derivative yields a maximum value at an addition amount of 1.94 parts; surface droplet permeation time function. (goodness of fit) The derivative yields a minimum value at an addition amount of 2.17 parts. To achieve a balance between the internal capillary water storage space and the surface hydrophilic permeation rate, the average value of 2.05 parts is taken as the theoretical optimal point. Based on industrial-scale feeding accuracy and error tolerance control, the final addition amount of polysiloxane-polyether copolymer is selected as 2 parts.

[0073] 2.4 Optimization of Triethylenediamine / Dibutyltin Dilaurate Addition Amount After preparing the premix and emulsion as described above, the amount of triethylenediamine / dibutyltin dilaurate added ranged from 0.3 to 0.8 parts by weight, with a gradient step of 0.1 parts by weight, setting up 6 experimental groups. 50.5 parts of MDI were added, rapidly stirred, poured, foamed, and cured at a constant temperature before demolding. The effect of the gel catalyst on the molding process and final performance was evaluated by detecting the milky white foaming time, wet tear strength, and saturated water absorption rate of each group's solution.

[0074] Milky white foaming time: The premix, emulsion, and diphenylmethane diisocyanate were added to a mixing container, and a high-precision stopwatch was used to synchronize the timing while rapid stirring was started. The apparent state of the mixture was then observed. Timing was stopped when the mixture changed from a transparent or translucent liquid to an opaque milky white, and the surface began to expand and foam. The time interval was recorded. This value characterizes the initial kinetic rates of the foaming and gelation reactions within the polyurethane system and the operating window for industrial casting.

[0075] The results are as follows Figure 6As shown, with increasing gel catalyst addition, the milky white foaming time and saturated water absorption rate exhibit a monotonically decreasing trend, while the wet tear strength shows a change of first increasing and then decreasing. A nonlinear boundary curve was fitted to the optimal window (750%~900%) for efficient water storage and flexibility of the saturated water absorption rate to obtain a safe range for the addition amount. Within this range, the maximum value of the wet tear strength was fitted, revealing that it reaches its maximum at an addition amount of 0.48 parts by weight, and at this point, the milky white foaming time is within the safe operating range for industrial continuous casting. Based on the feed tolerance of industrial equipment, the final addition amount of triethylenediamine / dibutyltin dilaurate was determined to be 0.5 parts.

[0076] Having established the optimal balance between the aforementioned micro-crosslinked network and foaming kinetics, and considering that mop foam materials are constantly exposed to a humid environment rich in organic dirt during actual use, making them prone to mold growth and oxidative degradation of the polymer backbone, this invention, without compromising the aforementioned high-permeability open-cell network and mechanical balance mechanism, further introduces 0.3 parts by weight of the antibacterial agent silver-loaded zirconium phosphate and 0.5 parts by weight of the liquid antioxidant Irganox 1135, namely isooctyl 3,5-bis(1,1-dimethylethyl)-4-hydroxyphenylpropionate, in the premix preparation stage.

[0077] Example 3 Reference Figures 7 to 9 This is the third embodiment of the present invention. This embodiment aims to optimize the process flow and correct parameters for the preferred formulation determined in the laboratory. Although the optimal formulation of the system has been established at the microscopic level, the scale-up process from small-scale trials to large-scale industrial production is often accompanied by dynamic changes in the physical field. Especially for rapid polyurethane foaming systems and high-porosity three-dimensional cross-linked networks, changes in the physical field often induce microstructural defects such as localized closed-cell formation, bubble collapse, or core coking, thereby affecting the dimensional stability and mechanical life of the final product. Therefore, it is necessary to adjust the key process parameters for continuous large-scale production to ensure that laboratory results can be stably and efficiently transformed into large-scale products.

[0078] 3.1 Optimization of High Shear Speed ​​and Shear Time 55 parts of hydrophilic polyether polyol, 30 parts of soft polyether polyol, 2 parts of TMP, 1 part of BDO / DEA, 0.3 parts of silver-loaded zirconium phosphate, and 0.5 parts of Irganox 1135 were sequentially added to an industrial-grade large-scale stirred tank equipped with a heating jacket. The jacket heating system was turned on to set the temperature inside the tank to 55°C, and the stirring device was started and stirred continuously for 35 minutes to obtain a homogeneous premix.

[0079] The shearing speed ranged from 500 to 1000 r / min with a gradient step of 100 r / min, and the shearing time ranged from 5 to 15 min with a gradient step of 1.0 min. Experimental groups were set up by cross-variable settings. Under this shearing action, 1.2 parts of deionized water and 2 parts of polysiloxane-polyether copolymer were added to the premix and uniformly dispersed to obtain an emulsion. 0.5 parts of triethylenediamine / dibutyltin dilaurate and 50.5 parts of MDI were added, rapidly stirred, poured, foamed, and cured at a constant temperature before demolding. The average droplet size, pore size distribution dispersion, and saturated water absorption rate of each group were measured to evaluate the process effect of different speeds and times.

[0080] The results are as follows Figure 7 , 8 As shown, with the increase of high shear rotation speed and shear time, the average droplet size and pore size distribution dispersion both show a trend of first decreasing and then increasing, while the saturated water absorption rate shows a change of first increasing and then decreasing. A safe range was defined by fitting the optimal window for efficient water storage and flexibility of the saturated water absorption rate. Within this range, the minimum values ​​of the average droplet size and pore size distribution dispersion were fitted, and their minimum values ​​were found to be (894.57 r / min, 11.63 min) and (902.33 r / min, 12.12 min), respectively. To achieve a balance between high shear work and interfacial thermodynamic stability, the average value (898.45 r / min, 11.88 min) was taken as the theoretical optimal point. Based on the rotation speed setting modulus and time management accuracy in large-scale industrial production, the process parameters for the high-shear microemulsion chemical section of this invention were finally determined to be: rotation speed 900 r / min, time 12 min.

[0081] 3.2 Optimization of High-Speed ​​Mixing Time After preparing the premix and emulsion as described above, the reactor was cooled to 30°C using an industrial cooling water system. 0.5 parts of triethylenediamine / dibutyltin dilaurate were added and stirred until homogeneous. Subsequently, 50.5 parts of MDI were injected using a high-pressure metering pump, and stirring was performed at 1350 r / min to obtain a foamed mixture. High-speed stirring was conducted from 20 to 30 s in 2-s increments, with six experimental groups. After pouring, foaming, and constant-temperature curing before demolding, samples were taken to test the wet tear strength, wet volume swelling rate, and saturated water absorption rate.

[0082] The results are as follows Figure 9As shown, with the extension of high-speed stirring time, the wet tear strength, wet volume swelling rate, and saturated water absorption rate all exhibit a change of first increasing and then decreasing. A nonlinear boundary curve fitting was performed on the optimal window for efficient water storage and flexibility of the saturated water absorption rate, defining a safe range. Within this safe range, the maximum values ​​of the wet tear strength and wet volume swelling rate were fitted, revealing that their maximum values ​​were at stirring times of 24.63 s and 23.86 s, respectively. To achieve a balance between high tensile strength and uniform swelling, the average value of 24.25 s was taken. Based on the parameter setting accuracy of industrial operating equipment, the final high-speed stirring time was determined to be 24 s.

[0083] 3.3 Constant temperature curing and demolding After obtaining the foamed mixture, it is poured into a mold preheated to 45°C within 5-8 seconds using an automatic pouring machine. The mixture is then allowed to stand at 45°C for 20 minutes to achieve stable foaming and initial gelation. Subsequently, the mold is conveyed to an industrial curing tunnel at 80°C for continuous curing for 2.5 hours to achieve deep curing of the cross-linked network. After curing, the finished product is removed from the tunnel and allowed to cool naturally to room temperature. It is then removed using an automatic demolding device to obtain the high water absorption polyurethane foam material.

[0084] Example 4 Reference Figure 10 , Figure 11 This is the fourth embodiment of the present invention. This embodiment provides a method for preparing a high-absorbency polyurethane foam material for mops. To ensure the stability of the crosslinked network density during mass production, this embodiment first performs an active hydrogen equivalent balancing calculation on the core formula before carrying out the specific physical preparation. The specific calculation and preparation process of this embodiment are as follows: I. Core Formula Equivalent Calculation (NCO Index Verification) The calculation of MDI usage in the system follows the following isocyanate index ( Calculation formula: In the formula: For MDI quality; The mass of each component containing active hydrogen (polyol, water, crosslinking agent, chain extender); This represents the active hydrogen equivalent of the corresponding component.

[0085] Equivalent of each core raw material ( The parameters for determination and definition are as follows: Liquefied modified MDI: average functionality Based on a preferred NCO content of 30.0%, its isocyanate equivalent ; Deionized water: relative molecular mass 18.02, functionality (One water molecule consumes two NCO groups to produce biuret crosslinking), water equivalent ; Hydrophilic polyether polyols: preferably those with high functionality A polyether with a hydroxyl value (OHV) of 112 mg KOH / g has a hydroxyl equivalent. .

[0086] Soft polyether polyols: preferably those with high functionality A polyether with a hydroxyl value (OHV) of 56.1 mg KOH / g has a hydroxyl equivalent. .

[0087] Trimethylolpropane (TMP): relative molecular mass 134.17, functionality hydroxyl equivalent ; 1,4-Butanediol (BDO): relative molecular mass 90.12, functionality hydroxyl equivalent ; Diethanolamine (DEA): relative molecular mass 105.14, functionality (Contains 2 terminal hydroxyl groups and 1 highly reactive secondary amino group with active hydrogen), its active hydrogen equivalent .

[0088] The results of the balanced calculation of the active hydrogen equivalent and isocyanate in the system are shown in Table 7: Table 7. Calculation of active hydrogen equivalent and isocyanate balance in the system. According to this embodiment, 50.5 parts of MDI (NCO%=30.0%) were added. Accounting: Total number of moles of NCO provided by the system = .

[0089] Actual isocyanate index = The calculation result is consistent with the preferred isocyanate index (1.05) set in this invention.

[0090] II. Industrialized Preparation Process S1 premix preparation 55 parts of hydrophilic polyether polyol, 30 parts of soft polyether polyol, 2 parts of trimethylolpropane, 1 part of 1,4-butanediol / diethanolamine, and functional additives (0.3 parts of antibacterial agent silver-loaded zirconium phosphate and 0.5 parts of liquid antioxidant Irganox 1135) were sequentially added to an industrial reactor equipped with a variable frequency stirring motor. The jacket heating was turned on, and the mixture was stirred continuously at medium speed at 55°C for 35 minutes to allow the components to fully dissolve and remove air bubbles while maintaining a certain viscosity, resulting in a homogeneous premix.

[0091] S2 High Shear Emulsification Pump 1.2 parts deionized water and 2 parts polysiloxane-polyether copolymer into the premixed liquid in the industrial reactor. Start the high-shear disperser in the reactor and set the speed to 900 r / min. Perform high-shear fluid treatment continuously for 12 min to break up and uniformly disperse the deionized water and foaming agent in the polyether polyol matrix to obtain an emulsion.

[0092] S3 Catalysis and Critical Mixing The cooling water circulation jacket of the industrial reactor was turned on to lower the system temperature to 30°C to provide a thermodynamically safe inert period. 0.5 parts of triethylenediamine / dibutyltin dilaurate were added to the reactor and stirred at medium speed for 6 minutes to ensure uniform distribution. Subsequently, 50.5 parts of diphenylmethane diisocyanate (MDI) were injected into the reactor using a high-pressure metering pump, while the variable frequency stirrer was adjusted to 1350 r / min and stirred at high speed for 24 seconds to obtain a foamed mixture.

[0093] S4 Casting and Curing After the mixing process is completed, the automatic control system opens the pneumatic discharge valve at the bottom of the vessel, and the foaming mixture is poured into a mold preheated to 45°C within 5-8 seconds using an automatic pouring machine. The mixture is then left to stand in the 45°C constant-temperature foaming section for 20 minutes to complete stable foaming and initial gelation. Subsequently, the mold is conveyed to an 80°C industrial curing tunnel for continuous curing for 2.5 hours to achieve deep curing of the cross-linked network. After curing, the finished product is removed from the tunnel and allowed to cool naturally to room temperature. It is then demolded without damage using automated equipment to obtain the finished foam material.

[0094] The prepared foam material has the following characteristics: milky white foaming time of 32.15 s, average droplet size of 1.13 μm, pore size distribution dispersion of 4.26%, saturated water absorption rate of 815.46%, wet tear strength of 26.58 N / cm, and wet volume swelling rate of 345.27%.

[0095] In summary, by designing the molecular structure and constructing a dynamic hybrid cross-linking network, the technical challenge of balancing high water absorption and good mechanical strength in existing polyurethane foam materials for mops has been effectively solved.

[0096] Specifically, in terms of cleaning performance, the specific gradient porous structure combined with the hydrophilic system allows the foam material to quickly penetrate and absorb surface water through the surface macropores, while the internal micropores provide a large water storage space, improving the overall water absorption rate and absorption speed. In terms of durability, the composite polyol system and crosslinking agent work synergistically to ensure the high tensile strength of the foam material, avoiding deformation and shedding defects under repeated daily compression. In terms of hygiene and processing, the uniform cell structure with a pore size of 50~100 μm and an open cell rate of ≥90% reduces stain residue to achieve antibacterial effect, while the controllable gel foaming rate avoids foam collapse and pinhole problems, ensuring the stability of industrial mass production.

[0097] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing a high-absorbency polyurethane foam material for mops, characterized in that, Includes the following steps: S1. By weight, 50-60 parts of hydrophilic polyether polyol, 25-35 parts of soft polyether polyol, 1-3 parts of trimethylolpropane, 0.5-1.5 parts of a compound chain extender composed of 1,4-butanediol and diethanolamine in a mass ratio of 1:0.8-1.2, and functional additives are stirred at 50-60 °C for 30-40 min to obtain a premixed solution; S2. Add 1-1.5 parts of deionized water and 1.5-2.5 parts of polysiloxane-polyether copolymer to the premixed liquid, and perform high shear treatment at a high shear speed of 800-1000 r / min for 10-15 min to obtain an emulsion; S3. Lower the system temperature, add 0.3-0.7 parts of a compound gel catalyst composed of triethylenediamine and dibutyltin dilaurate in a mass ratio of 1:0.5-0.8 to the emulsion and mix well; then inject 50-60 parts of diphenylmethane diisocyanate and stir at high speed at 1300-1400 r / min for 20-30 s to obtain a foamed mixture; S4. Pour the foaming mixture into a preheated mold within 5-8 seconds and let it stand to foam. After initial gelation and shaping, perform high-temperature curing, cool and demold to obtain the finished product.

2. The method for preparing high water-absorbency polyurethane foam material for mops according to claim 1, characterized in that, In step S1, the amount of hydrophilic polyether polyol added is 55 parts, the amount of soft polyether polyol added is 30 parts, the amount of trimethylolpropane added is 2 parts, and the amount of compound chain extender added is 1 part.

3. The method for preparing high water-absorbency polyurethane foam material for mops according to claim 1, characterized in that, In step S1, the functional additives include 0.3 parts of the antibacterial agent silver-loaded zirconium phosphate and 0.5 parts of the liquid antioxidant Irganox 1135; the stirring parameters are: stirring at 55°C for 35 min.

4. The method for preparing high water-absorbency polyurethane foam material for mops according to claim 1, characterized in that, In step S2, the amount of deionized water added is 1.2 parts, and the amount of polysiloxane-polyether copolymer added is 2 parts.

5. The method for preparing high water-absorbency polyurethane foam material for mops according to claim 1, characterized in that, In step S2, the high shear rotation speed is 900 r / min and the high shear time is 12 min.

6. The method for preparing high water-absorbency polyurethane foam material for mops according to claim 1, characterized in that, In step S3, the amount of the compound gel catalyst added is 0.5 parts, and the amount of the diphenylmethane diisocyanate added is 50.5 parts; the high-speed stirring parameters are 1350 r / min for 24 s.

7. The method for preparing high water-absorbency polyurethane foam material for mops according to claim 1, characterized in that, In step S4, the static foaming process is as follows: Using an automatic pouring machine, the foaming mixture is poured into a mold preheated to 45°C within 5-8 seconds, and allowed to stand at 45°C for 20 minutes to complete stable foaming and initial gel setting.

8. The method for preparing high water-absorbency polyurethane foam material for mops according to claim 1, characterized in that, In step S4, the high-temperature curing process is as follows: After the material has completed the initial gelation and shaping, it is sent into an industrial curing tunnel at 80°C for continuous curing for 2.5 hours to achieve deep curing of the cross-linked network.

9. The method for preparing high water-absorbency polyurethane foam material for mops according to claim 1, characterized in that, In step S4, the cooling and demolding process is as follows: After curing, the finished product is removed from the tunnel and allowed to cool naturally to room temperature. It is then removed using an automatic demolding device to obtain high water absorption polyurethane foam.

10. A high-absorbency polyurethane foam material for mops, prepared by any one of claims 1 to 9, characterized in that, The polyurethane foam material has a three-dimensional, fully open-cell network structure: its internal flexible backbone is a continuous solid-phase membrane constructed by deep cross-linking of the hydrophilic polyether polyol and the soft polyether polyol composite substrate with the diphenylmethane diisocyanate; a hydrophilic film constructed by the directional extension of the polysiloxane-polyether copolymer seamlessly covers the pore wall surface of the solid-phase membrane; the silver-loaded zirconium phosphate inorganic particles are uniformly embedded and anchored in the cross-linking nodes of the solid-phase membrane, and the solid-phase membranes are spatially interwoven to form a continuous, interconnected capillary water-storing pore structure.

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