A method of making a waterproof, moisture-permeable polyurethane glove

Abstract

This invention relates to the field of polyurethane glove manufacturing technology, specifically an innovative manufacturing method for waterproof and breathable polyurethane gloves with significantly improved waterproof, breathable, and mechanical properties. The method includes lining finishing, impregnation with a coagulant followed by drying, impregnation with polyurethane foam slurry followed by drying, impregnation with polyurethane slurry followed by drying, and impregnation with particle slurry followed by drying. During the drying process after impregnation, the hand mold's rotation, combined with improvements to its structure, generates airflow within the mold. This airflow is guided to the mold surface, circling around the impregnated area and creating airflow. This airflow effectively removes moisture generated during the drying process, accelerating the drying process and ensuring uniform drying. This avoids the problems of reduced waterproof performance, deteriorated mechanical properties, and altered breathability that often occur after polyurethane glove molding, thus improving the waterproof and breathable properties of the polyurethane gloves.

Description

Technical Field

[0001] This invention relates to the field of polyurethane glove manufacturing technology, specifically to an innovative manufacturing method for waterproof and breathable polyurethane gloves that significantly improves waterproof, breathable, and mechanical properties. Background Technology

[0002] Due to the nature of their work, workers' hands tend to sweat easily, and conventional gloves struggle to wick away this sweat effectively, leading to reduced hand comfort and, in severe cases, hand allergies and dermatitis. Half-gloves or yarn gloves offer some breathability but cannot prevent oil and water penetration, limiting their application in certain fields. Polyurethane gloves (PU gloves), being both waterproof and oil-resistant while maintaining a degree of breathability, are the best protective gloves for workers.

[0003] On November 22, 2021, the applicant disclosed a waterproof and breathable polyurethane glove in Chinese invention patent application number 202111385860.8, which adopts an impregnation molding process. The first layer is impregnated with a porous polyurethane coating, and the second layer is impregnated with a non-porous polyurethane coating. The second impregnation layer can prevent dust, detergent and other impurities from contaminating and clogging the first porous coating. The composite between the two coatings also improves the mechanical strength of the first coating and effectively reduces the decrease in moisture permeability caused by the deformation of the foam cells of the first coating due to external force.

[0004] In addition, the patent also discloses a production device for preparing waterproof and breathable polyurethane gloves. The bottom of the base of the production device is equipped with a purification mechanism and a filtration mechanism. The purification mechanism can filter the gas entering the drying chamber to prevent impurities and dust in the gas from being sprayed onto the outer surface of the hand mold, thereby improving the quality of the gloves drying.

[0005] However, the aforementioned production equipment did not solve the problems of moisture accumulation on the surface of the hand mold, uneven drying, and slow drying during the drying process. Furthermore, the production of polyurethane gloves requires at least four drying and heating processes. This means that if the hand mold dries unevenly during any one of the drying processes, it will affect the quality of the finished polyurethane gloves.

[0006] Meanwhile, regardless of whether it is coagulant, polyurethane foam slurry, or impregnation of polyurethane slurry, they all need to be rotated into the drying oven after impregnation. This requires the drying equipment to be set up with an open opening. Therefore, once the exhaust mechanism is set up on the drying oven to remove moisture, it will inevitably lead to the entry of external gas, which will disrupt the temperature balance inside the drying oven.

[0007] Therefore, there is an urgent need for a preparation method that can quickly divert the moisture generated during the drying of the hand mold during the polyurethane glove preparation process, especially during the drying process after impregnation, while preventing external air from entering the drying oven and disrupting the temperature balance, thereby improving the quality of the polyurethane glove preparation process. Summary of the Invention

[0008] To address the above problems, this invention provides a method for preparing waterproof and breathable polyurethane gloves. During the drying process after the hand mold is impregnated, the rotation of the hand mold, combined with improvements to its structure, generates airflow inside the mold. This airflow is guided to the surface of the hand mold, circling around the impregnated area and creating airflow. This airflow guides the moisture generated during the drying process of the hand mold surface, accelerating the drying process and ensuring uniform drying. This avoids the problems of reduced waterproof performance, deteriorated mechanical properties, and altered breathability after the polyurethane gloves are molded, thus improving the waterproof and breathable properties of the polyurethane gloves.

[0009] To achieve the above objectives, the present invention provides the following technical solution:

[0010] A method for preparing waterproof and breathable polyurethane gloves includes the following steps:

[0011] Step a: After fitting the inner liner onto the hand mold and making it fit smoothly, the hand mold, carrying the inner liner, is vertically inserted into the coagulant tank for immersion. After the hand mold is lifted until the coagulant no longer drips, the hand mold is swung until it is horizontally conveyed, and the hand mold rotates around its own central axis into the drying oven. The drying oven temperature is 50-60℃, for example, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60℃, and the drying temperature is 10-20 minutes, for example, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 minutes.

[0012] After drying in step b and step a, the hand mold is slowly and vertically immersed in the polyurethane foam slurry tank and then quickly lifted up, with the hand mold tilted upwards to a 30° angle with the horizontal plane. The hand mold is then rotated around its own central axis for 5 minutes.

[0013] After the hand mold has been rotated in steps c and b, it is swung to a horizontal position and then rotated around its own central axis into the oven. The oven is heated at 90°C for 20 minutes.

[0014] After the hand molds in steps d and c are dried, they are slowly and vertically inserted into the polyurethane slurry tank to immerse in the second layer of slurry. After immersion, the hand molds are quickly lifted and dripped for 3 minutes. They are then swung to a horizontal conveyor and rotated around their own central axis into the drying oven at 100-125℃, for example, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 120, 121, 122, 123, 124, or 125℃, for drying and heating for 20-30 minutes, for example, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30 minutes.

[0015] After drying and cooling to 30°C, the hand molds in steps e and d are vertically immersed in the particle slurry tank. After dripping for 3 minutes, the hand molds are swung to a horizontal conveyor and rotated around their own central axis into the drying oven at 100-125°C, for example, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 120, 121, 122, 123, 124, or 125°C, for 20-30 minutes, for example, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30 minutes, to form waterproof and breathable polyurethane gloves.

[0016] After the waterproof and breathable polyurethane gloves formed in steps f and d have cooled, they are demolded, trimmed, and then packaged.

[0017] In steps a, b, c, d, and e, when the hand mold rotates around its central axis, an airflow layer surrounds the outer side of the immersion area on the hand mold.

[0018] As an improvement, in step a, before the hand mold is impregnated with the coagulant, the lining is subjected to infrared pretreatment with an infrared wavelength range of 0.7 to 4.0 μm, for example, 0.7, 1.0, 1.2, 1.5, 1.7, 2.0, 2.3, 2.5, 2.7, 3.0, 3.2, 3.5, 3.7, or 4.0 μm.

[0019] As an improvement, in step b, the polyurethane foaming slurry uses a polyether-type polyurethane prepolymer as the base material, and the polyurethane foaming slurry also includes 5%-10% (e.g., 5, 6, 7, 8, 9, 10%) of polyethylene glycol and 0.2%-0.5% (e.g., 0.2, 0.3, 0.4, 0.5%) of organosilicon modifier. The molecular weight of the polyethylene glycol is 2000-4000 (here, molecular weight is relative molecular weight), and the organosilicon modifier is γ-aminopropyltriethoxysilane or its derivative.

[0020] As an improvement, in step d, the second slurry is a core-shell polyurethane emulsion, with the core layer being a high-hardness isocyanate-type polyurethane and the shell layer being a flexible polyether-type polyurethane, and the mass ratio of the two being 3:7-5:5.

[0021] As an improvement, the preparation method of the core-shell structured polyurethane emulsion includes the following steps:

[0022] Step t1: Preparation of core layer polyurethane prepolymer. In a four-necked flask equipped with a stirrer, thermometer, and reflux condenser, add isocyanate-type polyurethane prepolymer raw material, start stirring, control the speed at 100-150 r / min, raise the temperature to 80-85℃, slowly add the metered acetone, stir evenly to fully dissolve the prepolymer, add the chain extender ethylenediamine, control the reaction temperature at 80-85℃, react for 2-3 hours, stop the reaction, and obtain the core layer polyurethane prepolymer solution.

[0023] Step t2: Preparation of shell polyurethane prepolymer. Take another four-necked flask, add polyether-type polyurethane prepolymer raw material, and control the stirring speed at 100-150 r / min. Heat to 70-75℃, add acetone and stir to dissolve. Then add the metered chain extender ethylenediamine, control the reaction temperature at 70-75℃, and the reaction time is 1.5-2 h to obtain shell polyurethane prepolymer solution.

[0024] Step 3: Preparation of core-shell emulsion. Slowly add the shell polyurethane prepolymer solution to the core polyurethane prepolymer solution while stirring. Increase the stirring speed to 200-250 r / min. After mixing evenly, continue stirring for 30 min. Add the prepared emulsifier to the above mixed solution and stir for 15-20 min to fully emulsify the prepolymer. Add deionized water to the emulsion for dispersion. The amount of water added is 1-1.5 times the total mass of the polyurethane prepolymer. Stir and disperse at high speed at 1000-1500 r / min for 30-40 min to form a stable emulsion. Add triethylamine for neutralization and adjust the pH value of the emulsion to 7.5-8.5. Stir for 10-15 min. Remove acetone by vacuum distillation to obtain the core-shell polyurethane emulsion.

[0025] As an improvement, in step e, 2%-5% by mass of nano-titanium dioxide particles and 1%-2% by mass of waterproofing agent are added to the particle slurry. The waterproofing agent is perfluorobutyl sulfonic acid, an organic fluorine waterproofing agent.

[0026] As an improvement, the airflow layer formed on the dipped part of the hand mold is formed by the gas ejected from the pores of the un-dipped part of the hand mold toward the dipped part through rotation.

[0027] As an improvement, the hand mold consists of a mold and a rotating shaft. A planetary gear set is installed inside the hand mold. Through the planetary gear set, the mold and the rotating shaft are set to rotate at a relative speed. The rotating shaft is oscillatingly connected to a suspended chain conveyor and is driven to move by the suspended chain conveyor. A fan blade is installed at the end of the rotating shaft inside the mold. The fan blade rotates synchronously with the rotating shaft to form an airflow, which is discharged outward through an air hole.

[0028] As an improvement, the planetary gears in the planetary gear set are connected by an end cap provided on the unimpregnated end of the mold. The end cap covers the rotating shaft to form a guide wheel and a limiting block. The guide wheel is a circular roller, the limiting block is square, and the rotating shaft is provided with a roller-shaped friction wheel.

[0029] Along the movement path of the hand mold during its self-rotation, a guide friction track is laid parallel to the movement path. The guide friction track includes a guide part, a limiting part, and a friction part arranged in parallel. The guide part is configured to roll with the guide wheel, the limiting part is configured to slide with the limiting block, and the friction part is configured to roll and rub with the friction wheel.

[0030] As an improvement, the fan blades rotate with the shaft, and gas is introduced through the air inlet on the end cover. The air inlet is equipped with a filter screen to filter the gas.

[0031] The beneficial effects of this invention are as follows:

[0032] (1) This invention, through the horizontal rotation during the drying process of the hand mold (the hand mold rotates itself in the horizontal conveying state), combined with the special shape of the hand mold (i.e. the diameter of the dipped end of the hand mold is smaller than that of the un-dipped end) and the improvement of the hand mold structure, enables the internal airflow to be generated during the self-rotation, and the airflow can be guided to the surface of the hand mold, circling around the dipped part of the hand mold to form an airflow, which guides the hot air and moisture generated during drying, balances the drying temperature of the hand mold surface, and quickly removes the moisture generated on the surface of the hand mold, thereby avoiding the problems of reduced waterproof performance, deterioration of mechanical properties and change of moisture permeability after the polyurethane gloves are molded, improving the waterproof and moisture permeability of the polyurethane gloves, and the air cover formed by the airflow can also isolate the hand mold and prevent dust and impurities from falling during the drying process;

[0033] (2) The present invention pre-treats the lining with infrared radiation. The high-energy infrared radiation (wavelength is usually 200-400nm) can destroy the chemical bonds such as CC and CH on the surface and generate free radicals. Oxygen (O2) in the air participates in the reaction, which allows the free radicals to combine with oxygen to form polar oxygen-containing groups such as hydroxyl (-OH), carboxyl (-COOH), and carbonyl (C=O). These groups significantly increase the surface hydrophilicity and chemical activity, and increase the surface energy (from about 30-40mN / m to 50-60mN / m), making the coagulant (usually an aqueous solution) easier to wet and adsorb, thereby improving the activity of the lining surface and enhancing the binding force with the coagulant.

[0034] (3) In this invention, polyethylene glycol is added to polyurethane foam slurry. Polyethylene glycol has good hydrophilicity and can form hydrophilic channels in polyurethane slurry. When the gloves come into contact with water vapor, the water vapor can be quickly transferred through these hydrophilic channels, thereby significantly improving the moisture permeability of the gloves.

[0035] (4) In this invention, an organosilicon modifier is added to the polyurethane foam slurry. The organosilicon modifier can reduce the surface tension of the polyurethane slurry, making the bubbles generated during the foaming process more uniform and stable. If the bubbles are of different sizes or easily break during the foaming process, the internal structure of the glove will be uneven, affecting its mechanical properties and comfort. The organosilicon modifier can effectively improve this situation, making the foam structure more stable, thereby improving the overall strength, elasticity and other mechanical properties of the glove. It also helps to improve the smoothness and flatness of the glove surface.

[0036] (5) In this invention, a core-shell polyurethane emulsion is used as the second slurry. The core layer is made of high-hardness isocyanate polyurethane, which has strong forces between its molecular chains and has high hardness and modulus. When the glove is subjected to external force, the core layer can act like a skeleton to resist the deformation caused by the external force and bear most of the stress, thereby effectively preventing the destruction of the internal structure of the glove and improving the overall rigidity and deformation resistance of the glove. The shell layer is made of flexible polyether polyurethane, which gives the emulsion good elasticity and extensibility. During the bending, stretching and other deformation processes of the glove, the shell layer can undergo reversible deformation with the external force, absorb and disperse the external force energy, and avoid stress concentration in a certain part that causes the material to break.

[0037] In summary, the polyurethane gloves of the present invention have advantages such as high moisture permeability, large water contact angle, excellent waterproof performance, and enhanced mechanical properties. They are particularly suitable for the field of breathable and waterproof polyurethane glove manufacturing technology and have broad application prospects. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the preparation method in Example 1 of the present invention;

[0039] Figure 2 This is a schematic diagram of the three-dimensional structure of the hand mold in Embodiment 2 of the present invention. Figure 1 ;

[0040] Figure 3 This is a schematic diagram of the three-dimensional structure of the hand mold in Embodiment 2 of the present invention. Figure 2 ;

[0041] Figure 4 This is a partial cross-sectional view of the hand mold in Embodiment 2 of the present invention;

[0042] Figure 5 This is a schematic diagram of the three-dimensional structure of the end cap in Embodiment 2 of the present invention;

[0043] Figure 6 This is a schematic diagram of the planetary gear set mating structure in Embodiment 2 of the present invention;

[0044] Figure 7 This is a schematic diagram of the three-dimensional structure of the rotating shaft in Embodiment 2 of the present invention;

[0045] Figure 8 This is a schematic diagram of a partial structure of the friction track in Embodiment 2 of the present invention;

[0046] Figure 9 This is a schematic diagram of the internal structure of the mold of the present invention;

[0047] Figure 10 This is a schematic cross-sectional view of the limiting pin structure of the present invention;

[0048] Figure 11 This is a schematic diagram of the hand mold reversing mechanism in cooperation with the guide part and guide wheel of the present invention.

[0049] The attached diagram is labeled as follows: hand mold 1, air hole 10, impregnated part 11, unimpregnated part 12, limiting ring 121, mold 2, gas collection area 20, air inlet 200, gas flow channel 201, filter screen 202, end cap 21, mounting shaft 210, flange 211, limiting pin 212, ball 213, guide wheel 214, limiting block 215, rotating shaft 3, fan blade 31, friction wheel 33, planetary gear set 4, planetary gear 41, star gear 42, gear ring 43, friction track 5, guide part 51, limiting part 52, friction part 53. Detailed Implementation

[0050] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0051] The specific embodiments of the present invention will be described in detail below. However, it should be noted that the scope of protection of the present invention is not limited to these specific embodiments, but is determined by the claims in the appendix.

[0052] All publications, patent applications, patents, and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings commonly understood by those skilled in the art. In case of conflict, the definitions in this specification shall prevail.

[0053] When this specification uses the prefixes "known to those skilled in the art," "prior art," or similar terms to derive materials, substances, methods, steps, apparatus, or components, the objects derived from such prefixes cover those conventionally used in the art at the time the invention was proposed, but also include those that are not currently commonly used but will become generally recognized in the art as suitable for similar purposes.

[0054] It should be noted that the two or more aspects (or embodiments) disclosed in the context of this specification can be arbitrarily combined with each other, and the resulting technical solutions (such as methods or systems) are part of the original disclosure of this specification and also fall within the protection scope of this invention.

[0055] Unless otherwise specified, all percentages, parts, ratios, etc. mentioned in this specification are based on weight, unless being based on weight would not be in accordance with the common understanding of those skilled in the art.

[0056] Example 1:

[0057] like Figure 1 As shown, a method for preparing waterproof and breathable polyurethane gloves includes the following steps:

[0058] Step a: After fitting the inner lining onto the hand mold and making it fit smoothly, the hand mold carrying the inner lining is vertically inserted into the coagulant tank for immersion. After the hand mold is lifted until the coagulant no longer drips, the hand mold is swung until it is horizontally conveyed and rotates around its own central axis into the drying oven. The drying oven temperature is 50-60℃, and the drying is heated for 10-20 minutes.

[0059] After drying in step b and step a, the hand mold is slowly and vertically immersed in the polyurethane foam slurry tank and then quickly lifted up, with the hand mold tilted upwards to a 30° angle with the horizontal plane. The hand mold is then rotated around its own central axis for 5 minutes.

[0060] After the hand mold has been rotated in steps c and b, it is swung to a horizontal position and then rotated around its own central axis into the oven. The oven is heated at 90°C for 20 minutes.

[0061] After the hand molds in steps d and c are dried, they are slowly and vertically inserted into the polyurethane slurry tank to immerse the second layer of slurry. After immersion, the hand molds are quickly lifted and dripped for 3 minutes. They are then swung to be conveyed horizontally and rotated around their own central axis into the drying oven at 100-125℃ for 20-30 minutes.

[0062] After drying and cooling to 30°C, the hand molds in steps e and d are vertically inserted into the particle slurry tank to immerse in the particle slurry. After dripping for 3 minutes, the hand molds are swung to be conveyed horizontally and rotated around their own central axis into the drying oven at 100-125°C for 20-30 minutes to form waterproof and breathable polyurethane gloves.

[0063] After the waterproof and breathable polyurethane gloves formed in steps f and d have cooled, they are demolded, trimmed, and then packaged.

[0064] In steps a, b, c, d, and e, when the hand mold rotates around its central axis, an airflow layer surrounds the outer side of the immersion area on the hand mold.

[0065] It should be noted that uneven drying and slow drying speed during the polyurethane coating drying process after the polyurethane gloves are impregnated with polyurethane will affect the performance of the molded polyurethane gloves, as detailed below:

[0066] Reduced waterproof performance:

[0067] Water resistance failure (increased risk of leakage), uneven drying, and uncured "weak points" (such as pinholes, cracks, or unfused particles) on or inside the coating surface allow water to easily penetrate to the inside of the glove. For example, if the center of a thick coating is not completely dry, the outer layer cures to form a "shell," and the internal liquid polyurethane may swell or detach upon contact with water, creating leakage channels and slow drying. For solvent-based polyurethanes, incompletely evaporated solvents reduce the adhesion between the coating and the substrate (such as the glove's base fabric), making the coating prone to delamination upon contact with water. For water-based polyurethanes, undried moisture dilutes the coating, leading to discontinuous film formation and damage to the waterproof barrier.

[0068] The reduced water pressure resistance and the loose structure of the coating due to insufficient drying make it unable to withstand water pressure. When in contact with liquids (such as disinfectants in medical settings or industrial liquids), the liquid can easily penetrate into the inside of the glove, causing it to lose its protective function.

[0069] Deterioration of mechanical properties:

[0070] Decreased strength and abrasion resistance, uneven drying, and incomplete curing of localized areas (such as residual solvent or unreacted polyurethane prepolymer within thick coatings) lead to uneven overall crosslinking density. In areas where the coating is not fully dried, the polymer chains are highly mobile and have low mechanical strength, making them prone to breakage or wear under stress such as tension and friction. This can cause gloves to tear, fray, or develop surface fuzz. Slow drying speeds and prolonged exposure to moisture make the coating susceptible to external forces (such as stretching and folding during glove production), leading to microcracks or structural loosening within the coating. After curing, this results in "weak bonding points," significantly reducing mechanical strength (such as elongation at break and tensile strength).

[0071] Deterioration in elasticity and resilience, uneven or slow drying can prevent polyurethane molecular chains from fully cross-linking into a network structure, resulting in weak intermolecular forces, reduced coating elasticity, and gloves that are easily deformed and difficult to return to their original shape when worn, affecting fit and comfort.

[0072] Changes in moisture permeability:

[0073] Abnormal moisture permeability (usually elevated), uneven drying, and the presence of unevaporated solvents or incompletely cured "pore" areas in the coating create interconnected pores, allowing water vapor to pass through more easily and increasing moisture permeability. If the gloves are designed for low moisture permeability (e.g., in waterproof applications), this will reduce their protective effect. Slow drying speeds and incomplete evaporation of solvents (especially water in waterborne polyurethanes) can create "water traps" or microporous structures within the coating, increasing the pathways for water vapor conduction. Furthermore, incompletely cured polyurethane may further enlarge the pores due to swelling, leading to increased moisture permeability.

[0074] Uneven moisture permeability and uneven drying can lead to differences in porosity and density in different areas of the coating, resulting in inconsistent moisture permeability and affecting the overall functionality of the glove (such as the moisture resistance of medical gloves).

[0075] Therefore, the present invention requires an airflow layer to surround the immersion area on the hand mold. This layer protects against dust and impurities during the drying process, balances the temperature of different parts of the hand mold by utilizing gas flow, and ensures that the moisture generated during the drying process is quickly removed to prevent moisture accumulation.

[0076] In the production of polyurethane gloves, after impregnating the mold with a coagulant and slurry, the mold is rotated horizontally into the drying oven. This is primarily to ensure uniform drying and prevent slurry accumulation, thereby guaranteeing the quality and performance of the gloves. Specifically:

[0077] 1. Uniform drying: The rotating method ensures even heating of all parts of the mold surface, avoiding localized overheating or undercooling. If the mold enters the oven in a fixed position, the varying distances and angles between different parts and the heat source result in uneven heating. For example, the side closer to the heat source may become too hot, causing the slurry to dry too quickly or even burn, while the side farther from the heat source may not dry sufficiently, affecting the overall quality of the gloves. By rotating the mold, the coagulant and slurry on the mold surface can dry at a more uniform temperature, resulting in more even drying and ensuring stable glove performance. Furthermore, the rotating process utilizes gas flow to promote heat distribution, further enhancing the uniform temperature of the mold and promoting efficient drying.

[0078] 2. Avoid slurry accumulation. After impregnation with coagulant or slurry, the slurry distribution on the glove surface may be uneven, exhibiting a certain degree of fluidity. If the mold is not rotated before entering the oven, the slurry may flow downwards and accumulate at the bottom or in certain areas of the mold under gravity, resulting in inconsistent thickness across different parts of the glove and affecting its appearance and performance. During rotation, the mold is in dynamic motion, effectively dispersing the slurry and reducing slurry accumulation due to gravity. This ensures a uniform distribution of the slurry on the glove surface, contributing to a glove product with uniform thickness and stable quality. Furthermore, the surrounding airflow blows from the large-diameter end of the mold down to the small-diameter end, thus not affecting the flow of the coagulant or slurry and instead binding the coagulant or slurry to the mold surface, resulting in a good adhesion effect.

[0079] Therefore, the formation of an airflow layer on the surface of the mold during the horizontal rotation process can bring beneficial effects in terms of drying efficiency, quality stability, and process control, thus optimizing the polyurethane glove manufacturing process.

[0080] Specifically as follows:

[0081] Accelerating the drying process: The airflow layer can speed up the evaporation of moisture and solvents on the glove surface. The high-speed airflow can continuously remove water or solvent molecules that have vaporized due to heating from the glove surface, disrupting the gas-liquid balance near the surface. This allows internal moisture and solvents to diffuse to the surface and evaporate more quickly, thereby shortening the drying time and improving production efficiency.

[0082] Uniform drying: It helps to even out the temperature and humidity distribution on the mold surface. Uniform and stable airflow can make the heat transfer to all parts of the mold more consistent, avoiding local overheating or undercooling, ensuring that the coagulant and slurry dry evenly on the glove surface, preventing problems such as inconsistent glove thickness and uneven surface caused by uneven drying, and improving the stability of glove quality.

[0083] Reduced contaminant adhesion: Continuous airflow forms a barrier, reducing the adhesion of airborne dust, impurities, and other particles to the glove surface. In production environments, some suspended particles are unavoidable in the air. The airflow layer can blow these impurities away from the mold surface, reducing the risk of glove surface contamination, ensuring glove surface cleanliness, and thus improving the appearance quality and performance of the gloves.

[0084] Stable process environment: The airflow layer can isolate the mold from external environmental interference to a certain extent, stabilizing the microenvironment around the mold. For example, the impact of external temperature and humidity fluctuations on the mold is weakened by the airflow layer, keeping the mold under relatively stable temperature and humidity conditions. This is beneficial for precise control of production process parameters and ensuring consistent product quality.

[0085] In a preferred embodiment, in step a, the lining impregnated with the coagulant is treated with infrared light, preferably with a wavelength of 1.5 μm. Infrared light helps maintain a uniform moisture content in the lining during finishing, effectively preventing sizing penetration and resulting in a poor hand feel during the subsequent sizing process. It also avoids localized sizing penetration or poor adhesion due to uneven coagulant content in the lining, thus effectively improving glove quality. In practical applications, infrared heating systems typically handle the crucial task of removing 35% to 40% of the fabric's moisture content. After impregnation with the coagulant, the liquid content of the lining can be effectively reduced from 75% to 45% to 50%. This level of moisture removal reduces the burden on subsequent drying processes and ensures the fabric is in a suitable humidity state before entering the next stage of processing. (If the lining is too wet and contains too much coagulant, the adhesion of the sizing after the gloves are dipped in the sizing will be poor, and the gloves will not be durable; if it is too dry, the sizing will seep through, and the feel of the gloves will be worse. After the lining is dipped in the coagulant, it will generally flatten out after one minute. This results in the fingertips of the lining having high moisture content and the cuffs having low moisture content. When heated by infrared radiation, the fingertips with high moisture content absorb more heat and dry faster, while the cuffs dry more slowly, thus achieving a uniform overall humidity of the gloves.)

[0086] In addition, high heating efficiency is a prominent feature of infrared drying technology. Infrared rays can transfer energy to the moisture in the fabric in a very short time, causing the moisture to heat up and evaporate rapidly. This rapid heating process greatly shortens the drying time and improves production efficiency. The energy of infrared rays can be directly absorbed by water and converted into heat energy, reducing energy loss during the transfer process and making the drying process more energy-efficient and effective. This not only meets the current societal requirements for energy conservation and environmental protection but also reduces production costs for enterprises and enhances their competitiveness.

[0087] Furthermore, in a preferred embodiment of the present invention, in step b, the polyurethane foaming slurry uses a polyether-type polyurethane prepolymer as the base material. The polyurethane foaming slurry also includes 5%-10% polyethylene glycol by mass and 0.2%-0.5% organosilicon modifier by mass. The molecular weight of polyethylene glycol is 2000-4000, and the organosilicon modifier is γ-aminopropyltriethoxysilane or its derivative. In addition, foaming agents, foam stabilizers and other additives are also added to the polyurethane foaming slurry.

[0088] Polyether-type polyurethane prepolymers possess excellent flexibility and hydrolysis resistance. In the actual use of gloves, frequent bending and stretching are required, and the flexibility of polyether-type polyurethane prepolymers ensures that the gloves are not prone to cracking under these operations. Its hydrolysis resistance extends the service life of gloves in humid environments and prevents material performance degradation due to moisture. It is particularly suitable for the preparation of gloves that need to come into contact with water or be used in humid environments. At the same time, polyether-type polyurethane prepolymers have good processing performance and are easy to mix evenly with other additives, thereby meeting the needs of different production processes.

[0089] As a non-limiting example of an organosilicon modifier, γ-aminopropyltriethoxysilane or its derivatives, with polydimethylsiloxane (PDMS) as the main chain, are formed by chemically grafting amino groups (-NH2) to form γ-aminopropyltriethoxysilane (CAS No.: 919-30-2). Its molecular structure is as follows:

[0090] H2N(CH2)3Si(OC2H5)3

[0091] The amino group is located at the γ position of the silicon atom, and the three ethoxy groups (-OC2H5) serve as hydrolysis-active groups.

[0092] Reactive design:

[0093] Amino groups (-NH2) can undergo ureation with isocyanate groups (-NCO) in polyurethane prepolymers, covalently bonding siloxane segments to the polyurethane molecular network to form a stable cross-linked structure.

[0094] Ethoxy group (-OC2H5): hydrolyzes in aqueous slurry to generate silanol group (-SiOH), which further forms hydrogen bond or covalent bond with hydroxyl group (-OH) on the substrate surface, enhancing the interfacial bonding force.

[0095] The mechanism of action and performance improvement are as follows:

[0096] Foam stability optimization:

[0097] Surface tension control: Polysiloxane segments have extremely low surface tension (approximately 20 mN / m), which can spread rapidly on the slurry surface, reduce the interfacial energy between bubbles, inhibit bubble merging and rupture, and make the foam pore size distribution more uniform (pore size deviation ≤10%).

[0098] Dynamic stabilization effect: The polar groups of amino groups can be adsorbed on the surface of the bubble liquid film to form an elastic interface layer, which resists mechanical stress during the foaming process (such as centrifugal force during rotational impregnation) and reduces foam collapse.

[0099] Increased crosslinking density: The reaction between amino groups and isocyanate groups introduces silicon-oxygen bonds (Si-O-Si) into the polyurethane network. The bond energy (452 ​​kJ / mol) is higher than that of ordinary C-C bonds (348 kJ / mol), which significantly improves the tensile strength (+20%-30%) and tear resistance (+15%-20%) of the material.

[0100] Stress dispersion mechanism: The flexibility of the siloxane chain segments can buffer external stress, avoid cracking caused by stress concentration, and increase the elongation at break of the glove to 300%-400%.

[0101] Synergistic effect:

[0102] Combination with polyethylene glycol (PEG): The hydrophilicity of PEG and the hydrophobicity of organosilicon complement each other, forming a "hydrophilic-hydrophobic" microphase separation structure in the slurry. This not only improves the moisture permeability (1500-2000 g / (m²·24h)) but also inhibits PEG crystallization through the steric hindrance effect of siloxane segments, thus maintaining the flexibility of the material.

[0103] The performance indicators of the polyurethane gloves modified with organosilicon agents of this invention are compared with those of traditional polyurethane gloves in Table 1 below:

[0104] Table 1

[0105]

[0106] In addition, in some preferred embodiments, in step d, the second slurry is a core-shell polyurethane emulsion, the core layer is a high-hardness isocyanate-type polyurethane, and the shell layer is a flexible polyether-type polyurethane, with a mass ratio of 3:7-5:5.

[0107] Specifically, the preparation method of the core-shell structured polyurethane emulsion includes the following steps:

[0108] Step t1: Preparation of core layer polyurethane prepolymer. In a four-necked flask equipped with a stirrer, thermometer, and reflux condenser, add isocyanate-type polyurethane prepolymer raw material, start stirring, control the speed at 100-150 r / min, raise the temperature to 80-85℃, slowly add the metered acetone, stir evenly to fully dissolve the prepolymer, add the chain extender ethylenediamine, control the reaction temperature at 80-85℃, react for 2-3 hours, stop the reaction, and obtain the core layer polyurethane prepolymer solution.

[0109] Step t2: Preparation of shell polyurethane prepolymer. Take another four-necked flask, add polyether-type polyurethane prepolymer raw material, and control the stirring speed at 100-150 r / min. Heat to 70-75℃, add acetone and stir to dissolve. Then add the metered chain extender ethylenediamine, control the reaction temperature at 70-75℃, and the reaction time is 1.5-2 h to obtain shell polyurethane prepolymer solution.

[0110] Step 3: Preparation of core-shell emulsion. Slowly add the shell polyurethane prepolymer solution to the core polyurethane prepolymer solution while stirring. Increase the stirring speed to 200-250 r / min. After mixing evenly, continue stirring for 30 min. Add the prepared emulsifier to the above mixed solution and stir for 15-20 min to fully emulsify the prepolymer. Add deionized water to the emulsion for dispersion. The amount of water added is 1-1.5 times the total mass of the polyurethane prepolymer. Stir and disperse at high speed at 1000-1500 r / min for 30-40 min to form a stable emulsion. Add triethylamine for neutralization and adjust the pH value of the emulsion to 7.5-8.5. Stir for 10-15 min. Remove acetone by vacuum distillation to obtain the core-shell polyurethane emulsion.

[0111] The core-shell structure tightly bonds two polyurethanes with different properties, forming a structural system that combines rigidity and flexibility. When subjected to external forces, the core layer initially bears the main stress, while the shell layer alleviates the stress through deformation and distributes the stress evenly throughout the structure. The two work together to effectively enhance the material's resistance to external damage, giving the glove both high strength and good toughness, thus significantly improving its mechanical strength.

[0112] As a non-limiting example of a core-shell structured polyurethane emulsion, the core layer raw material is selected from a high-hardness isocyanate-type polyurethane prepolymer, with the isocyanate group (-NCO) content controlled at 4%-6% and the hydroxyl value at 20-30 mgKOH / g.

[0113] As a non-limiting example of a core-shell structured polyurethane emulsion, the shell material is selected from a flexible polyether-type polyurethane prepolymer with a hydroxyl value of 50-60 mg KOH / g and an isocyanate group (-NCO) content of 2%-3%.

[0114] As a non-limiting example of a core-shell structured polyurethane emulsion, the emulsifier is a combination of a nonionic emulsifier and anionic emulsifier. The nonionic emulsifier can be nonylphenol polyoxyethylene ether (NP-10), and the anionic emulsifier can be sodium dodecylbenzenesulfonate (SDBS). The mass ratio of the two is 2:1, and the total amount of emulsifier is 3%-5% of the total mass of the polyurethane prepolymer. The neutralizing agent is triethylamine, and the amount is 1.0-1.2 times the carboxyl content in the emulsion. The chain extender is ethylenediamine, and the amount is 0.8-0.9 times the amount of isocyanate group. The solvent is acetone, and the amount is 30%-50% of the total mass of the polyurethane prepolymer, used to reduce the viscosity of the system and facilitate the reaction.

[0115] In a preferred embodiment, in step e, 2%-5% by mass of nano-titanium dioxide particles and 1%-2% by mass of waterproofing agent are added to the particle slurry. The waterproofing agent is perfluorobutyl sulfonic acid, an organic fluorine waterproofing agent.

[0116] The core components of organofluorine waterproofing agents are surfactants or polymers containing fluorocarbon chains, which mainly achieve waterproofing through the low surface energy properties of fluorine. The specific composition typically includes: fluorocarbon surfactants (main component, accounting for 60%-80%) and auxiliary components (accounting for 20%-40%).

[0117] Structural characteristics of fluorocarbon surfactants: The molecule contains long-chain fluorocarbon groups (such as C...). n F 2n+1 -, n=6-12), with hydrophilic groups (such as carboxyl groups, sulfonic acid groups, polyoxyethylene groups, etc.) attached to the ends.

[0118] Typical varieties:

[0119] Short-chain fluorocarbon surfactants: such as perfluorohexyl sulfonic acid (PFHxS, C6), perfluorooctyl sulfonic acid (PFOS, C8, gradually being replaced due to environmental restrictions), and perfluorobutyl sulfonic acid (PFBS, C4, an environmentally friendly alternative).

[0120] Fluorocarbon acrylate copolymers: polymers with fluorocarbon side chains are formed by copolymerizing fluorocarbon monomers (such as dodecafluoroheptyl methacrylate) with acrylate monomers, which have both waterproof and film-forming properties.

[0121] The auxiliary ingredients include:

[0122] Solvents / dispersants: water (aqueous systems), ethanol (co-solvent), or nonionic surfactants (such as polyoxyethylene ethers) to ensure uniform dispersion of fluorides.

[0123] Stabilizers: Polyols (such as glycerol) or small molecule organic acids (such as acetic acid) prevent fluorocarbon chain aggregation and improve emulsion stability.

[0124] Crosslinking agent (optional): Small molecules containing hydroxyl or amino groups (such as ethylenediamine) react with the hydroxyl groups on the substrate surface to enhance the adhesion of the waterproofing agent.

[0125] The waterproofing effect of organofluorine waterproofing agents stems from the synergistic effect of "low surface energy" and "molecular film barrier," with the specific mechanism as follows:

[0126] 1. Surface energy reduction effect (core mechanism):

[0127] The bond energy of fluorocarbon chains (CF bond energy is about 485 kJ / mol) is much higher than that of CH bonds (about 414 kJ / mol), and the electronegativity of fluorine atoms is extremely strong, resulting in weak intermolecular forces and extremely low surface energy of fluorocarbon chains (about 10-15 mN / m, far lower than the 72 mN / m of water).

[0128] When the waterproofing agent is dispersed in the slurry and coated on the material surface, the fluorocarbon chains are oriented to form a hydrophobic interface, which increases the contact angle of water droplets (>90°), making it difficult for them to spread and penetrate. This is manifested as the "lotus effect" (water droplets roll off and carry away pollutants).

[0129] 2. Molecular membrane barrier effect:

[0130] Fluorocarbon polymers (such as fluorocarbon acrylate copolymers) form a dense film during the drying process, filling the micropores on the material surface and physically preventing moisture from penetrating.

[0131] If it contains a crosslinking agent, the waterproofing agent can react with the hydroxyl and amino groups on the surface of the substrate (such as polyurethane or glass fiber) to enhance the adhesion of the film layer through chemical bonding and improve water resistance.

[0132] 3. Synergistic effect with nano-titanium dioxide:

[0133] The nano-titanium dioxide (2%-5%) added to the slurry can form a rough surface (similar to the micro-nano structure of lotus leaves), which combines with the low surface energy of the fluorocarbon chain to produce a "roughness-surface energy synergistic hydrophobic effect", further improving the waterproof level (the contact angle can reach more than 150°, with a superhydrophobic effect).

[0134] It is worth noting that due to the bioaccumulation of PFOS / PFOA, most mainstream products currently use C6 / C4 short-chain fluorides (such as PFHxS, PFBS) or fluorine-free alternatives (such as silicone-based waterproofing agents). However, organofluorine compounds still dominate in high-end fields (such as protective gloves and outdoor materials) due to their superior performance.

[0135] Example 2:

[0136] like Figures 2 to 11As shown, in some preferred embodiments, the airflow layer formed on the impregnated portion 11 of the hand mold 1 is formed by the rotation of gas ejected from the pores 10 of the unimpregnated portion 12 of the hand mold 1 toward the impregnated portion 11.

[0137] As a non-limiting embodiment of the hand mold 1, the hand mold 1 is composed of a mold 2 and a rotating shaft 3. A planetary gear set 4 is provided inside the hand mold 1. Through the planetary gear set 4, the mold 2 and the rotating shaft 3 are set to rotate at a relative speed difference (that is, the rotation speed of the rotating shaft 3 is greater than the rotation speed of the mold 2). The rotating shaft 3 is oscillatingly connected to a suspended chain conveyor and is driven to move by the suspended chain conveyor. A fan blade 31 is provided at the end of the rotating shaft 3 located inside the mold 2. The fan blade 31 rotates synchronously with the rotating shaft 3 to form a blowing gas to form an airflow. A gas collection area 20 is provided in the mold 2 directly opposite the fan blade 31. After the airflow converges in the gas collection area 20, it is divided into corresponding air holes 10 through the gas flow channel 201 opened on the mold 2 and discharged outward. When discharged, the gas flows along the axial direction of the mold towards the immersion part 11. With the self-rotation of the mold 2, the gas directly forms a flowing gas layer on the outer surface of the immersion part 11.

[0138] As a non-limiting embodiment of the planetary gear set 4, the planetary gear 41 in the planetary gear set 4 is mounted and connected by an end cap 21 provided on the unimpregnated end 12 of the mold 2. The end cap 21 covers the unimpregnated end 12 of the mold 2, and a limiting ring 121 is recessed inward on the unimpregnated end 12. A plurality of limiting pins 212 are passed through the flange 211 of the end cap 21 covering the limiting ring 121. The limiting pins 212 and the flange 211 are connected by a threaded engagement, and the end of the limiting pin 212 that abuts against the bottom of the groove of the limiting ring 121 is provided with rolling balls, so that the mold 2 is rotated relative to the end cap 21. The sun gear 42 is fitted with the rotating shaft 3 and connected by a keyway. The gear ring 43 is interference-fitted with the mold 2 and connected by a keyway. Specifically, when the rotating shaft 3 rotates, it first drives the sun gear 42 and the fan blade 31 to rotate. At this time, the end cover 21 is in a circumferential fixed limit state, that is, it does not have rotational freedom. Therefore, the planet gear 41 can only rotate around the mounting shaft 210 on the end cover 21 and cannot revolve around the sun gear 42. Through the transmission of the planet gear 41, the gear ring 43 rotates. Under the drive of the gear ring 43, the mold 2 rotates with the gear ring 43, realizing the differential rotation structure between the mold 2 and the rotating shaft 3.

[0139] As a non-limiting embodiment of the end cap 21, the end cap 21 encloses the rotating shaft 3 to form a guide wheel 214 and a limiting block 215. The guide wheel 214 is arranged as a circular roller, the limiting block 215 is arranged as a square, and the rotating shaft 3 is provided with a roller-shaped friction wheel 33.

[0140] Meanwhile, along the movement path of the hand mold 1 during its self-rotation, a guide friction track 5 is laid parallel to the movement path. The guide friction track 5 includes a guide part 51, a limiting part 52, and a friction part 53 arranged in parallel. The guide part 51 is rolled in cooperation with the guide wheel 214 to guide the switching of the hand mold 1 from vertical to horizontal state. The limiting part 52 is slidably engaged with the limiting block 215. Through the sliding cooperation between the limiting part 52 and the limiting block 215, the circumferential degree of freedom of the end cover 21 is limited. The friction part 53 is rolled and frictionally engaged with the friction wheel 33, so that the rotating shaft 3 can achieve self-rotation through friction.

[0141] It should also be explained in detail here that when the overhead chain conveyor drives the hand mold 1 for linear movement, the swing angle of the hand mold 1 depends on the angle of the rolling engagement between the guide part 51 and the guide wheel 214. That is, when the hand mold 1 needs to be in a vertical position, the hinged part between the rotating shaft 3 and the overhead chain conveyor can rotate and swing to a vertical position due to the hand mold 1's own weight. However, when the hand mold 1 is tilted upwards to a 30° angle with the horizontal plane and when it is in a horizontal rotation state, both of these working states require the guidance... Part 51 cooperates with guide wheel 214. For example, when hand mold 1 is tilted upwards to form a 30° angle with the horizontal plane, guide part 51 is set in a bent and twisted state. When guide wheel 214 rolls along guide part 51, it can change the tilt angle of hand mold 1. The principle of hand mold 1 switching from a vertical state to a horizontal state is also the effect caused by the change in the bending and twisting angle of guide part 51. It should be emphasized that in the path where hand mold 1 is not in a flat rotation state, limit part 52 and friction part 53 are not set in this path.

[0142] Furthermore, as a non-limiting embodiment of the fan blade 31, the fan blade 31 rotates with the shaft 3 and introduces gas through the air inlet 200 opened on the end cover 21. The air inlet 200 is provided with a filter screen 201 for filtering the gas. The filter screen 201 filters impurities and dust in the air and retains the impurities and dust on the filter screen 201. Therefore, after the hand mold 1 completes the molding and preparation of a polyurethane glove once or after completing a certain number of polyurethane glove molding and preparation cycles, the filter screen 201 needs to be rinsed and washed with water to remove the impurities and dust on the filter screen 201.

[0143] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing waterproof and breathable polyurethane gloves, characterized in that, Includes the following steps: Step a: After fitting the inner lining onto the hand mold and making it fit smoothly, the hand mold carrying the inner lining is vertically inserted into the coagulant tank for immersion. After the hand mold is lifted until the coagulant no longer drips, the hand mold is swung until it is horizontally conveyed and rotates around its own central axis into the drying oven. The drying oven temperature is 50-60℃, and the drying is heated for 10-20 minutes. After drying in step b and step a, the hand mold is slowly and vertically immersed in the polyurethane foam slurry tank and then quickly lifted up, with the hand mold tilted upwards to a 30° angle with the horizontal plane. The hand mold is then rotated around its own central axis for 5 minutes. After the hand mold has been rotated in steps c and b, it is swung to a horizontal position and conveyed, and the hand mold rotates around its own central axis into the drying oven, where it is dried and heated at 90°C for 20 minutes. After the hand molds in steps d and c are dried, they are slowly and vertically inserted into the polyurethane slurry tank to immerse the second layer of slurry. After immersion, the hand molds are quickly lifted and dripped for 3 minutes. They are then swung to be conveyed horizontally and rotated around their own central axis into the drying oven at 100-125℃ for 20-30 minutes. After drying and cooling to 30°C, the hand molds in steps e and d are vertically inserted into the particle slurry tank to immerse in the particle slurry. After dripping for 3 minutes, the hand molds are swung to be conveyed horizontally and rotated around their own central axis into the drying oven at 100-125°C for 20-30 minutes to form waterproof and breathable polyurethane gloves. After the waterproof and breathable polyurethane gloves formed in steps f and d have cooled, they are demolded, trimmed, and then packaged. In steps a, b, c, d, and e, when the hand mold rotates around its own central axis, an airflow layer surrounds the outside of the immersion part of the hand mold. The airflow layer formed on the immersion part of the hand mold comes from the gas sprayed from the air holes of the unimmersion part of the hand mold toward the immersion part through rotation. The hand mold consists of a mold and a rotating shaft. A planetary gear set is installed inside the hand mold. Through the planetary gear set, the mold and the rotating shaft are set to rotate at a relative speed. The rotating shaft is oscillatingly connected to a suspended chain conveyor and is driven to move by the suspended chain conveyor. A fan blade is installed at the end of the rotating shaft inside the mold. The fan blade rotates synchronously with the rotating shaft to form an airflow. The airflow is discharged outward through the air hole. The planetary gears in the planetary gear set are connected and mounted by end caps on the unimpregnated end of the mold. The end caps cover the rotating shaft to form a guide wheel and a limiting block. The guide wheel is a circular roller and the limiting block is a square one. The rotating shaft is equipped with a roller-shaped friction wheel. Along the movement path of the hand mold during its self-rotation, a guide friction track is laid out parallel to the movement path. The guide friction track includes a guide part, a limiting part and a friction part arranged in parallel. The guide part is configured to roll with the guide wheel, the limiting part is configured to slide with the limiting block, and the friction part is configured to roll with the friction wheel. The fan blades rotate with the shaft, and gas is introduced through the air inlet on the end cover. The air inlet is equipped with a filter screen to filter the gas.

2. The method for preparing waterproof and breathable polyurethane gloves according to claim 1, characterized in that: In step a, before the hand mold is impregnated with the coagulant, the lining is pretreated with infrared light, with the infrared wavelength range being 0.7 to 4.0 μm.

3. The method for preparing waterproof and breathable polyurethane gloves according to claim 1, characterized in that: In step b, the polyurethane foaming slurry uses polyether-type polyurethane prepolymer as the base material. The polyurethane foaming slurry also includes 5%-10% polyethylene glycol by mass and 0.2%-0.5% organosilicon modifier by mass. The molecular weight of polyethylene glycol is 2000-4000, and the organosilicon modifier is γ-aminopropyltriethoxysilane or its derivative.

4. The method for preparing waterproof and breathable polyurethane gloves according to claim 1, characterized in that: In step d, the second slurry is a core-shell polyurethane emulsion. The core layer is made of high-hardness isocyanate polyurethane, and the shell layer is made of flexible polyether polyurethane. The mass ratio of the two is 3:7-5:

5.

5. The method for preparing waterproof and breathable polyurethane gloves according to claim 4, characterized in that, The preparation method of a core-shell structured polyurethane emulsion includes the following steps: Step t1: Preparation of core layer polyurethane prepolymer. In a four-necked flask equipped with a stirrer, thermometer, and reflux condenser, add isocyanate-type polyurethane prepolymer raw material, start stirring, control the speed at 100-150 r / min, raise the temperature to 80-85℃, slowly add the metered acetone, stir evenly to fully dissolve the prepolymer, add the chain extender ethylenediamine, control the reaction temperature at 80-85℃, react for 2-3 hours, stop the reaction, and obtain the core layer polyurethane prepolymer solution. Step t2: Preparation of shell polyurethane prepolymer. Take another four-necked flask, add polyether-type polyurethane prepolymer raw material, and control the stirring speed at 100-150 r / min. Heat to 70-75℃, add acetone and stir to dissolve. Then add the metered chain extender ethylenediamine, control the reaction temperature at 70-75℃, and the reaction time is 1.5-2 h to obtain shell polyurethane prepolymer solution. Step 3: Preparation of core-shell emulsion. Slowly add the shell polyurethane prepolymer solution to the core polyurethane prepolymer solution while stirring. Increase the stirring speed to 200-250 r / min. After mixing evenly, continue stirring for 30 min. Add the prepared emulsifier to the above mixed solution and stir for 15-20 min to fully emulsify the prepolymer. Add deionized water to the emulsion for dispersion. The amount of water added is 1-1.5 times the total mass of the polyurethane prepolymer. Stir and disperse at high speed at 1000-1500 r / min for 30-40 min to form a stable emulsion. Add triethylamine for neutralization and adjust the pH value of the emulsion to 7.5-8.

5. Stir for 10-15 min. Remove acetone by vacuum distillation to obtain the core-shell polyurethane emulsion.

6. The method for preparing waterproof and breathable polyurethane gloves according to claim 1, characterized in that: In step e, 2%-5% by mass of nano-titanium dioxide particles and 1%-2% by mass of waterproofing agent are added to the particle slurry. The waterproofing agent is perfluorobutyl sulfonic acid, an organic fluorine waterproofing agent.

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