Preparation method of fluorine-free labor protection shoe leather
Patent Information
- Application Number
- CN202610932409.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-06-26
- Publication Date
- 2026-08-21
Smart Images
Figure CN122610376A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of shoe and leather manufacturing technology, and in particular to a method for preparing fluorine-free safety leather. Background Technology
[0002] As a crucial component of labor protection products, the performance of safety footwear directly impacts the safety and comfort of workers' feet. Currently, the industry primarily uses fluorinated resins or fluorinated waterproofing agents to treat safety footwear, leveraging the low surface energy of fluorocarbon compounds to impart excellent waterproof, oil-proof, and chemical corrosion-resistant properties. Specifically, existing technologies typically use fluorinated polyurethane resin as the main component of the impregnation slurry, combined with fluorinated waterproofing finishing agents to treat microfiber base fabric, and then use a dry lamination process to produce protective safety footwear. While this method achieves good waterproofing and durability, the process is relatively mature, and the product performance is stable, giving it a dominant position in the safety footwear market.
[0003] However, existing technologies for preparing fluorinated safety leather have significant environmental drawbacks and technological bottlenecks. First, fluorocarbons (such as PFOA and PFOS) are persistent organic pollutants, difficult to degrade in the environment, and can enter the human body through bioaccumulation, posing a potential threat to the ecological environment and human health. With increasingly stringent global environmental regulations, the use of fluorinated products is facing increasingly strict restrictions. Second, existing fluorine-free alternative technologies often struggle to balance hydrolysis resistance and waterproofing. Ordinary fluorine-free resins exhibit poor hydrolysis resistance in humid and hot environments, leading to problems such as decreased peel strength and surface powdering during use. Furthermore, the waterproofing effect of fluorine-free waterproofing agents is significantly inferior to that of fluorinated products, failing to meet the requirements for use in high-humidity environments. In addition, the existing fluorine-free preparation processes lack sufficient synergy between various steps. Base impregnation, waterproofing treatment, and dry bonding are often optimized as independent processes, lacking systematic process integration. This results in the final product's overall performance failing to reach the level of fluorinated products, severely restricting the market promotion and application of fluorine-free safety leather.
[0004] The purpose of this invention is to provide a method for preparing fluorine-free safety leather, which solves the problems in the prior art where fluorine-free safety leather is difficult to balance hydrolysis resistance and waterproof performance, and where the preparation process lacks systematic synergistic optimization.
[0005] To achieve the above objectives, the present invention provides a method for preparing fluorine-free safety shoe leather, comprising the following steps:
[0006] S1 uses a fluorine-free hydrolysis-resistant resin to formulate a wet-process base impregnation slurry, and prepares a fluorine-free hydrolysis-resistant base through an ultrafiber base impregnation process;
[0007] S2 uses a polyurethane-based fluorine-free waterproofing agent to waterproof the microfiber workwear base fabric, resulting in a waterproof base fabric.
[0008] S3 uses a fluorine-free, hydrolysis-resistant resin to formulate a dry-laying mixture. The mixture is then bonded to a waterproofed base fabric using a dry-laying process to produce fluorine-free, hydrolysis-resistant workwear leather.
[0009] In the section "Preparing a wet-process base impregnation slurry using a fluorine-free hydrolysis-resistant resin and preparing a fluorine-free hydrolysis-resistant base through an ultrafiber base impregnation process", the fluorine-free hydrolysis-resistant resin is formulated by weight as follows: 100 parts DMF, 20 parts PTMEG2000, 15 parts PTMEG3000, 10 parts PCL2000, 7 parts MDI, 2 parts BDO, 1 part EG, and 0.5 parts hydrolysis-resistant stabilizer; the wet-process base slurry is formulated by weight as follows: 100 parts fluorine-free hydrolysis-resistant resin, 30 parts DMF, 5 parts colorant, and 0.5 parts silicone oil pore-opening agent.
[0010] In the section "Preparing a wet-process base impregnation slurry using a fluorine-free hydrolysis-resistant resin, and then preparing a fluorine-free hydrolysis-resistant base through a microfiber base impregnation process," the microfiber base impregnation process includes:
[0011] The needle-punched nonwoven fabric is impregnated in a wet-process base slurry tank, and the resin is fully penetrated into every gap of the needle-punched nonwoven fabric by squeezing with pressure rollers.
[0012] The resin is then transferred to a coagulation bath with a DMF concentration of 10-40% to allow it to fully coagulate. Finally, it is washed with water to remove all the DMF, resulting in a fluorine-free, hydrolysis-resistant base.
[0013] The DMF concentration gradient in the coagulation bath is controlled as follows: 40% DMF concentration in the first stage coagulation bath, 30% DMF concentration in the second stage coagulation bath, and 10% DMF concentration in the third stage coagulation bath. The resin is gradually solidified from the outside to the inside through the three-stage gradient coagulation, forming a dense and uniform microporous structure.
[0014] The section on “using polyurethane-based fluorine-free waterproofing agent to waterproof microfiber workwear fabric to obtain waterproof base fabric” includes the following steps: immersing the base fabric in an aqueous emulsion containing polyurethane-based fluorine-free waterproofing agent for two immersions to obtain waterproof base fabric.
[0015] The concentration of the polyurethane-based fluorine-free waterproofing agent is 40-50%, and it is dried at 140-150℃ after impregnation.
[0016] In the section "Preparing a dry lamination mixture using a fluorine-free hydrolysis-resistant resin, and bonding the mixture with a waterproof-treated base fabric through a dry lamination process to prepare fluorine-free hydrolysis-resistant workwear leather", the dry lamination mixture is formulated by weight as follows: 100 parts fluorine-free hydrolysis-resistant resin, 50 parts DMF, 8 parts colorant, 0.5 parts leveling agent, and 0.5 parts yellowing resistant additive.
[0017] In the section "Preparing a dry-laying slurry using a fluorine-free hydrolysis-resistant resin, and bonding the slurry to a waterproof-treated base fabric via a dry-laying process to prepare fluorine-free hydrolysis-resistant workwear leather," the dry-laying process employs a release paper transfer lamination process, including:
[0018] The release paper is pre-baked, and then dry resin is applied to the release paper to form the first coating layer with a thickness of 10-15 mils.
[0019] When it is semi-dry, apply dry resin again on the first coating layer to form a second coating layer with a thickness of 20-25 mils.
[0020] Apply the coating again to form a third layer;
[0021] After the dry resin has reached a certain viscosity, the waterproof base fabric is attached to the resin, and then pressed, dried, and released from the molding paper to obtain fluorine-free safety leather.
[0022] This invention discloses a method for preparing fluorine-free safety leather footwear. The method utilizes a compound of PTMEG2000 and PTMEG3000, combined with a carbodiimide-based hydrolysis-resistant stabilizer, to significantly improve the resin's hydrolysis resistance, enabling the leather to maintain good mechanical properties even in humid and hot environments. A polyurethane-based fluorine-free waterproofing agent, combined with an optimized two-stage impregnation process, forms a uniform and dense waterproof membrane on the base surface, achieving a waterproof effect comparable to fluorine-containing products. The entire process avoids the use of fluorine-containing compounds, preventing the emission of fluorocarbons and aligning with the trend of green environmental protection. Through precise matching and gradient control of process parameters at each stage, the stability and consistency of product quality are ensured. Attached Figure Description
[0023] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.
[0024] Figure 1 This is a flowchart of a method for preparing a fluorine-free safety leather for work shoes provided by the present invention.
[0025] Figure 2 This is a flowchart of the microfiber base impregnation process.
[0026] Figure 3This is a flowchart of the release paper transfer and lamination process. Detailed Implementation
[0027] The embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, but should not be construed as limiting the present invention.
[0028] Please see Figures 1 to 3 This invention provides a method for preparing fluorine-free safety shoe leather, comprising the following steps:
[0029] S1 uses a fluorine-free hydrolysis-resistant resin to formulate a wet-process base impregnation slurry, and prepares a fluorine-free hydrolysis-resistant base through an ultrafiber base impregnation process;
[0030] The formulation of the fluorine-free hydrolysis-resistant resin by weight is as follows: 100 parts DMF, 20 parts PTMEG2000, 15 parts PTMEG3000, 10 parts PCL2000, 7 parts MDI, 2 parts BDO, 1 part EG, and 0.5 parts hydrolysis-resistant stabilizer; the formulation of the wet-process base slurry by weight is as follows: 100 parts fluorine-free hydrolysis-resistant resin, 30 parts DMF, 5 parts color paste, and 0.5 parts silicone oil pore-opening agent.
[0031] The microfiber base impregnation process includes:
[0032] S11 involves impregnating the needle-punched nonwoven fabric into a wet-process base slurry tank, and then using pressure rollers to squeeze the resin into every gap of the needle-punched nonwoven fabric.
[0033] S12 is then transferred to a coagulation bath with a DMF concentration of 10-40% to allow the resin to fully coagulate. Finally, the DMF is washed out completely with water to obtain a fluorine-free hydrolysis-resistant base.
[0034] The DMF concentration gradient in the coagulation bath is controlled as follows: 40% DMF concentration in the first stage coagulation bath, 30% DMF concentration in the second stage coagulation bath, and 10% DMF concentration in the third stage coagulation bath. Through three-stage gradient coagulation, the resin is gradually cured from the outside to the inside, forming a dense and uniform microporous structure.
[0035] Specifically, firstly, a fluorine-free hydrolysis-resistant resin is prepared by weight: 100 parts DMF, 20 parts PTMEG2000, 15 parts PTMEG3000, and 10 parts PCL2000 are added to a reactor and stirred until homogeneous. The mixture is then heated to 70-80°C, and 7 parts MDI are added for a prepolymerization reaction for 2-3 hours. Subsequently, the temperature is lowered to 60-70°C, and 2 parts BDO and 1 part EG are added for a chain extension reaction for 1-2 hours. Finally, 0.5 parts of a hydrolysis-resistant stabilizer are added, and the mixture is stirred for 30 minutes to obtain the fluorine-free hydrolysis-resistant resin. Next, a wet-process base slurry is prepared: 100 parts of the above-mentioned fluorine-free hydrolysis-resistant resin are mixed with 30 parts DMF, 5 parts colorant, and 0.5 parts silicone oil pore-opening agent. After stirring until homogeneous, the mixture is degassed to obtain the wet-process base impregnation slurry. Next, the microfiber base impregnation process is carried out: the needle-punched nonwoven fabric is continuously introduced into the impregnation slurry tank, and the resin is fully penetrated into each fiber gap of the needle-punched nonwoven fabric by the squeezing action of the upper and lower pressure rollers; then the impregnated nonwoven fabric is passed through a three-stage gradient coagulation bath (the first coagulation bath has a DMF concentration of 40%, the second coagulation bath has a DMF concentration of 30%, and the third coagulation bath has a DMF concentration of 10%), so that the resin gradually coagulates from the outside to the inside, forming a dense and uniform microporous structure; finally, the DMF is washed out completely in the water washing tank, and after drying, fluorine-free hydrolysis-resistant base is obtained.
[0036] S2 uses a polyurethane-based fluorine-free waterproofing agent to waterproof the microfiber workwear base fabric, resulting in a waterproof base fabric.
[0037] The base fabric is immersed twice in an aqueous emulsion containing a polyurethane-based fluorine-free waterproofing agent to obtain a waterproof base fabric; the concentration of the polyurethane-based fluorine-free waterproofing agent is 40-50%, and the fabric is dried at 140-150℃ after immersion.
[0038] Specifically, the fluorine-free hydrolysis-resistant base fabric prepared in step S1 (as the base fabric) is immersed in an aqueous emulsion containing a polyurethane-based fluorine-free waterproofing agent for two dip-impregnation treatments. The first dip-impregnation uses dip-impregnation rollers, controlling the roll-off rate at 80-85%, allowing the fluorine-free waterproofing agent to fully penetrate the base fabric fibers. After 5-10 minutes of penetration equilibrium, a second dip-impregnation is performed, controlling the roll-off rate at 70-75%, ensuring the waterproofing agent forms a uniform waterproof film on the fiber surface. Finally, the base fabric is dried in an oven at 140-150℃ to cure the waterproofing agent into a film, resulting in the waterproofed base fabric. The design of the two dip-impregnation process fully considers the penetration mechanism and film-forming characteristics of the fluorine-free waterproofing agent. The first high roll-off rate dip-impregnation ensures the waterproofing agent fully penetrates the fiber interior, while the second lower roll-off rate dip-impregnation forms a dense waterproof film on the fiber surface. The penetration equilibrium time between the two dip-impregnations allows sufficient time for the waterproofing agent molecules to diffuse and orient, thereby forming a uniform and continuous waterproof film on the fiber surface. Controlling the drying temperature is also crucial. A drying temperature of 140-150℃ can ensure that the waterproofing agent is fully cross-linked and cured without causing thermal damage to the base fabric.
[0039] S3 uses a fluorine-free, hydrolysis-resistant resin to formulate a dry-laying mixture. The mixture is then bonded to a waterproofed base fabric using a dry-laying process to produce fluorine-free, hydrolysis-resistant workwear leather.
[0040] The dry-process veneer mixing slurry has the following formula by weight: 100 parts of fluorine-free hydrolysis-resistant resin, 50 parts of DMF, 8 parts of color powder, 0.5 parts of leveling agent, and 0.5 parts of yellowing-resistant additive.
[0041] The dry lamination process employs a release paper transfer lamination process, including:
[0042] S31 pre-baked the release paper, then applied dry resin onto the release paper to form the first coating layer, with a coating thickness of 10-15 mils;
[0043] When S32 is semi-dry, apply dry resin again on the first coating layer to form a second coating layer with a thickness of 20-25 mils.
[0044] S33 is applied again to form a third coating layer;
[0045] After the S34 dry resin has reached a certain viscosity, the waterproof base fabric is attached to the resin, and after pressing, drying, and release from the molding paper, fluorine-free safety leather is obtained.
[0046] Specifically, firstly, a dry-process laminating mixture is prepared by weight: 100 parts of fluorine-free hydrolysis-resistant resin, 50 parts of DMF, 8 parts of colorant, 0.5 parts of leveling agent, and 0.5 parts of anti-yellowing agent are mixed, stirred evenly, and degassed to obtain the dry-process laminating mixture. Then, a release paper transfer laminating process is used: the release paper is pre-baked to 60-70℃, and the dry resin is applied to the release paper through a coating head to form the first coating layer, with a thickness of 10-15 mils. This is then pre-baked to a semi-dry state at 80-90℃. When the first coating layer is semi-dry, the dry resin is applied again to form the second coating layer, with a thickness of 20-25 mils, and pre-baked at 100-110℃. This process is repeated once more to form the third coating layer, which is then pre-baked at 120-130℃ until the viscosity is suitable. Finally, the waterproof-treated base fabric prepared in step S2 is laminated onto the third coating layer. Next, a three-stage pressing process is adopted: the pressure in the first pressing zone is 0.3-0.5 MPa and the temperature is 100-110℃, which allows the base fabric to initially contact the resin and eliminate air bubbles; the pressure in the second pressing zone is 0.5-0.8 MPa and the temperature is 120-130℃, which allows the resin to fully bond with the base fabric; the pressure in the third pressing zone is 0.2-0.3 MPa and the temperature is 110-120℃, which stabilizes the bonding interface and prevents excessive penetration; finally, after drying and release from the molding paper, fluorine-free safety leather is obtained. The design of the three-layer coating process fully considers the functional positioning of each layer. The first coating layer is relatively thin (10-15 mils), mainly serving to bond the release paper and provide surface texture; its thinness helps to achieve a clear surface texture. The second coating layer is thicker (20-25 mils) and is the main functional layer of the leather, providing mechanical properties and thickness. The third coating layer mainly serves to bond with the base fabric; its thickness and viscosity have been optimized to ensure good adhesion to the waterproofed base fabric. The drying temperature gradient of the three coating layers has also been carefully designed; the temperature gradient from low to high facilitates the gradual evaporation of solvents and the gradual curing of resins, avoiding defects such as surface skinning and internal blistering.
[0047] The above-disclosed embodiments are merely one or more preferred embodiments of this application and should not be construed as limiting the scope of this application. Those skilled in the art can understand that all or part of the processes for implementing the above embodiments and equivalent changes made in accordance with the claims of this application still fall within the scope of this application.
Claims
1. A method for preparing fluorine-free safety shoe leather, characterized in that, Includes the following steps: A wet-process base impregnation slurry was prepared using a fluorine-free hydrolysis-resistant resin, and a fluorine-free hydrolysis-resistant base was prepared through an ultrafiber base impregnation process. Waterproofing the microfiber workwear base fabric was performed using a polyurethane-based fluorine-free waterproofing agent to obtain the waterproofed base fabric. A dry-laying mixture is prepared using a fluorine-free hydrolysis-resistant resin. The mixture is then bonded to a waterproofed base fabric using a dry-laying process to produce fluorine-free hydrolysis-resistant workwear leather.
2. The method for preparing fluorine-free safety leather for work shoes as described in claim 1, characterized in that, In the section "Preparing a wet-process base impregnation slurry using a fluorine-free hydrolysis-resistant resin and preparing a fluorine-free hydrolysis-resistant base through an ultrafiber base impregnation process", the fluorine-free hydrolysis-resistant resin is formulated by weight as follows: 100 parts DMF, 20 parts PTMEG2000, 15 parts PTMEG3000, 10 parts PCL2000, 7 parts MDI, 2 parts BDO, 1 part EG, and 0.5 parts hydrolysis-resistant stabilizer; the wet-process base slurry is formulated by weight as follows: 100 parts fluorine-free hydrolysis-resistant resin, 30 parts DMF, 5 parts color paste, and 0.5 parts silicone oil pore-opening agent.
3. The method for preparing fluorine-free safety shoe leather as described in claim 2, characterized in that, In the section "Preparing a wet-process base impregnation slurry using a fluorine-free hydrolysis-resistant resin, and preparing a fluorine-free hydrolysis-resistant base through a microfiber base impregnation process," the microfiber base impregnation process includes: The needle-punched nonwoven fabric is impregnated in a wet-process base slurry tank, and the resin is fully penetrated into every gap of the needle-punched nonwoven fabric by squeezing with pressure rollers. The resin is then transferred to a coagulation bath with a DMF concentration of 10-40% to allow it to fully coagulate. Finally, it is washed with water to remove all the DMF, resulting in a fluorine-free, hydrolysis-resistant base.
4. The method for preparing fluorine-free safety leather for work shoes as described in claim 3, characterized in that, The DMF concentration gradient in the coagulation bath is controlled as follows: 40% DMF concentration in the first stage coagulation bath, 30% DMF concentration in the second stage coagulation bath, and 10% DMF concentration in the third stage coagulation bath. Through three-stage gradient coagulation, the resin is gradually cured from the outside to the inside, forming a dense and uniform microporous structure.
5. The method for preparing fluorine-free safety leather for work shoes as described in claim 1, characterized in that, The process of “using polyurethane-based fluorine-free waterproofing agent to waterproof microfiber workwear fabric to obtain waterproof base fabric” includes the following steps: immersing the base fabric in an aqueous emulsion containing polyurethane-based fluorine-free waterproofing agent for two immersions to obtain waterproof base fabric. The concentration of the polyurethane-based fluorine-free waterproofing agent is 40-50%, and it is dried at 140-150℃ after impregnation.
6. The method for preparing fluorine-free safety leather for work shoes as described in claim 1, characterized in that, In the section "Preparing a dry lamination mixture using a fluorine-free hydrolysis-resistant resin, and bonding the mixture with a waterproof-treated base fabric through a dry lamination process to prepare fluorine-free hydrolysis-resistant workwear leather", the dry lamination mixture is formulated by weight as follows: 100 parts of fluorine-free hydrolysis-resistant resin, 50 parts of DMF, 8 parts of colorant, 0.5 parts of leveling agent, and 0.5 parts of anti-yellowing agent.
7. The method for preparing fluorine-free safety leather for work shoes as described in claim 6, characterized in that, In the section "Preparing a dry-laying slurry using a fluorine-free hydrolysis-resistant resin, and bonding the slurry to a waterproof-treated base fabric via a dry-laying process to prepare fluorine-free hydrolysis-resistant workwear leather," the dry-laying process employs a release paper transfer lamination technique, including: The release paper is pre-baked, and then dry resin is applied to the release paper to form the first coating layer with a thickness of 10-15 mils. When it is semi-dry, apply dry resin again on the first coating layer to form a second coating layer with a thickness of 20-25 mils. Apply the coating again to form a third layer; After the dry resin has reached a certain viscosity, the waterproof base fabric is attached to the resin, and then pressed, dried, and released from the molding paper to obtain fluorine-free safety leather.