Leather powder and color fixing agent and preparation method thereof

Abstract

The invention belongs to the field of leather finishing auxiliaries, and particularly relates to a leather powder fixing agent and a preparation method thereof. The leather powder fixing agent is prepared from the following raw materials in parts by weight: 5 to 20 parts of polyvinyl alcohol, 10 to 20 parts of wax emulsion, 3 to 10 parts of matting filler, 10 to 20 parts of polyurethane brightener, 5 to 15 parts of organic silicon feeling agent emulsion and 40 to 70 parts of water. The preparation method comprises the following steps: dissolving polyvinyl alcohol, adding other raw materials, stirring and filtering. The product has excellent powder fixation and color fixation effects on split leather, can maintain good hand feeling and velvet feeling of leather, has small influence on color, and is suitable for industrial production.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of leather finishing aids, and particularly relates to a leather powder fixing and color fixing agent and a preparation method thereof. BACKGROUND

[0002] Leather manufacturing needs processes such as tanning, dyeing, finishing, etc. In the dyeing process, dyes adhere to collagen fibers through physical / chemical action, but the binding force is weak, the water resistance of dyeing is limited, and the color can easily fade due to water, friction or light. Leather color fixing agent is a chemical aid for leather products, its main function is to improve the color fastness of dyes on leather, prevent the leather from fading or discoloring during processing and use. Two-layer leather will also produce a lot of inorganic pigment residues and leather scraps due to inorganic pigment coloring or buffing processes, so it also needs the function of powder fixing. For two-layer leather, due to its more and longer pile, it brings higher difficulty to color fixing, and also causes obvious color difference of the leather itself after general color fixing agent spraying, and problems such as hard and rough hand feeling and poor pile retention after color fixing agent treatment.

[0003] Especially with the gradual popularity of two-layer leather, consumers have continuously increasing requirements for the performance of two-layer leather, such as having good color fixing effect while effectively fixing powder, having a moist hand feeling and good pile retention; further additional requirements have less influence on color light, do not stick when stacked, are environmentally friendly and do not release formaldehyde, etc. For two-layer leather, due to its more and longer pile, it brings higher difficulty to color fixing, and also causes obvious color difference of the leather itself after general color fixing agent spraying, and problems such as hard and rough hand feeling after color fixing agent treatment. At present, there are few color fixing agents for leather two-layer on the market, and the functions are single, the color fixing effect is poor, and it is urgent to develop efficient, environmentally friendly and multi-functional leather color fixing agents.

[0004] Patent No. CN119824701A discloses a kind of high color fastness of soap washing resistant home textile dyeing process. The color fixing step is to immerse the dyed fabric into the color fixing liquid for color fixing, then take out, wash, dry, complete dyeing and finishing, and obtain the dyed fabric. The raw materials of the color fixing liquid include 60-80 parts of water, 5-15 parts of silane modified nano titanium dioxide, 10-20 parts of polyvinyl alcohol, 0.5-2 parts of dispersing agent and 0.1-1 parts of stabilizer. The silane modified nano titanium dioxide can prevent fading caused by ultraviolet light, and can improve the overall stability and adhesion. The polyvinyl alcohol as a film-forming material can form a dense protective layer, significantly improving the color fastness of the fabric. However, when used on the surface of leather by spraying, although it can significantly improve the powder fixing and color fixing grade, it will cause the leather pile to be too closed, the hand feeling to be rough, the pile retention to be poor, and the color to be obviously deepened.

[0005] The patent with the publication number CN117209711A discloses a kind of cationic water-based polyurethane fixing agent for leather and its preparation method.Although it improves the utilization rate of dye, reduces environmental pollution, improves the color fastness of product, and gives the leather soft hand feeling to some extent, the wet rub is only 0.5 level, and the fixing effect is not obviously improved.

[0006] Therefore, based on this, the technical scheme of the present application is proposed. SUMMARY

[0007] To solve the problems existing in the prior art, the present application provides a kind of leather powder fixing agent, which comprises the following raw materials by weight: polyvinyl alcohol 5~20 parts, wax emulsion 10~20 parts, matting filler 3~10 parts, polyurethane brightener 10~20 parts, organic silicon hand feel agent emulsion 5~15 parts and water 40~70 parts.

[0008] Preferably, the leather powder fixing agent comprises the following raw materials by weight: polyvinyl alcohol 10 parts, wax emulsion 15 parts, matting filler 5 parts, polyurethane brightener 10 parts, organic silicon hand feel agent emulsion 10 parts and water 50 parts.

[0009] In order to facilitate the understanding of the present application, the role of the raw materials of the present application is described as follows: (1) Polyvinyl alcohol: as a film-forming material, it can form a local discontinuous film, combine with dye through van der Waals force and hydrogen bond, prevent dye migration, increase leather surface smoothness, reduce fiber dust shedding caused by friction, and improve fixing effect.

[0010] (2) Wax emulsion: gives leather a waxy and moisturizing feel, softens the stiffness of polyvinyl alcohol film, increases the softness of leather, enhances the pile retention of leather, and improves the anti-blocking property of leather to prevent sticking when stacking.

[0011] (3) Matting filler: adjusts light scattering, reduces the deepening effect of leather surface caused by fixing agent treatment, makes the color of leather more natural, and improves the wear resistance and texture of the coating.

[0012] (4) Polyurethane brightener: forms a soft and friction-resistant film, combines with hydroxyl and carboxyl groups in leather collagen, prevents chromium powder from falling off, forms a cross-linked structure after high temperature, enhances the film strength and dry and wet rub resistance, and improves the durability of powder fixing.

[0013] (5) Organic silicon hand feel agent emulsion: further optimizes the hand feel of leather, makes it more delicate and smooth, enhances the scratch resistance and wear resistance of leather, and improves the overall performance with other raw materials.

[0014] (6) Water: as a solvent, it makes the raw materials uniformly dispersed, forms a stable emulsion system, and is convenient for subsequent processing and use.

[0015] Further, the polyvinyl alcohol and the polyurethane brightener are synergistic, the local film forming of the polyvinyl alcohol and the cross-linking film forming of the polyurethane brightener are synergistic, which prevents dye migration and enhances film strength, significantly improves color fastness and rubbing resistance.

[0016] The wax emulsion and the silicone feel agent emulsion jointly act: the roughness after the film forming of the polyvinyl alcohol is compensated, the soft and moist wax feeling and the delicate and smooth hand feeling are given to the leather, and the pile feeling retention is enhanced.

[0017] The matt filler and the polyurethane brightener are synergistic: the light scattering effect of the matt filler and the film forming characteristics of the polyurethane brightener are matched, the deepening effect of the leather surface is effectively weakened, the color is closer to the original leather, and the wear resistance of the coating is improved.

[0018] The polyvinyl alcohol and the wax emulsion, the matt filler and the like are synergistic: the polyvinyl alcohol provides a dispersion carrier for other raw materials, the wax emulsion, the matt filler and the like are uniformly distributed in the system, and the comprehensive performance such as hand feeling and color stability is considered while the product is fixed and the powder is fixed.

[0019] Preferably, the polyvinyl alcohol has a degree of polymerization of 500-2500 and an alcoholysis degree of 80-100%.

[0020] Preferably, the wax emulsion is one of wood wax emulsion, Fischer-Tropsch wax, polyethylene wax, polypropylene wax, oxidized polyethylene wax and polyamide wax.

[0021] More specifically, the wax emulsion of the present application is a commercially available product, preferably DOWELLER WAX 5053, DOWELLER WAX 5050 produced by Sichuan Dawei Technology Co., Ltd. or wax emulsion FI-50 produced by Star Company, the physical and chemical data and characteristics of which are shown in Table 1.

[0022] Table 1 Index DOWELLER WAX 5053 DOWELLER WAX 5050 FI-50 Solid content (%) 12.5±1 8.5±0.5 7.5±0.5 Characteristics Fine and comfortable hand feeling, full waxiness without affecting color brightness No impact on coating gloss, enhanced coating waxiness, and improved hand comfort Good release from board, soft, and natural waxiness Preferably, the matt filler is an inorganic matt filler.

[0023] More specifically, the matt filler of the present application is a commercially available product, and the structure is a silica dispersion, preferably DOWELLER FILLER 4683 or DOWELLER FILLER 4686 produced by Sichuan Dawei Technology Co., Ltd., the physical and chemical data and characteristics of which are shown in Table 2.

[0024] Table 2 Index DOWELLER FILLER 4683 DOWELLER FILLER 4686 Solid content (%) 18±1 18±1 Characteristics Inorganic matting filler, fine hand feeling, and no color lightening and greying on dark color leather Inorganic matting filler, fine hand feeling, reduced plastic feel, and no color lightening and greying on dark color leather Preferably, the polyurethane brightener is a water-based polyurethane resin.

[0025] More specifically, the polyurethane brightener of the present application is a commercially available product, and is an anionic aliphatic matt type polyurethane, preferably DOWELLISH TOP M7228 or DOWELLISH TOP M7225 produced by Sichuan Dawei Science and Technology Co., Ltd., the physical and chemical data and characteristics of which are shown in Table 3.

[0026] Table 3 Index DOWELLISH TOP M7228 DOWELLISH TOP M7225 Solid content (%) 16±1 16±1 Characteristics Soft and opaque film formation, natural and smooth touch, strong matting effect, no whitening after finishing, good dry and wet rub resistance, and wear resistance Soft and opaque film formation, dry touch, no whitening after finishing, and excellent dry rub resistance and wear resistance Preferably, the silicone feel agent emulsion is one of a methyl silicone oil emulsion, a methyl hydrogen silicone oil emulsion, an amino silicone oil emulsion, an epoxy silicone oil emulsion, and a polyether modified silicone oil emulsion.

[0027] More specifically, the silicone feel agent emulsion of the present application is a commercially available product, and is preferably DOWELLFEL F8211 or DOWELLFEL F8229 produced by Sichuan Dawei Science and Technology Co., Ltd., or HM-283 produced by Star Company, the physical and chemical data and characteristics of which are shown in Table 4.

[0028] Table 4 Index DOWELLFEL F8211 DOWELLFEL F8229 HM-283 Solid content (%) 20±1 58±1 37±1 Characteristics Long-lasting fine and soft wax hand feeling Moist and fine hand feeling, significantly improved friction and wear resistance Wear-resistant and scratch-resistant, providing smooth and soft wax hand feeling Based on the same technical concept, another aspect of the present application provides a preparation method of a leather powder fixing and color fixing agent, the preparation method comprising the following steps: (1) dissolving polyvinyl alcohol in water to obtain a polyvinyl alcohol solution; (2) adding a wax emulsion, a matt filler, a polyurethane brightener, and a silicone feel agent emulsion to the polyvinyl alcohol solution, and filtering after stirring to obtain the leather powder fixing and color fixing agent.

[0029] Preferably, in step (1), the polyvinyl alcohol is added to water at room temperature and a rotation speed of 300-600 r / min, then the temperature is raised to 70-90°C for dissolution, and the solution is stirred at a rotation speed of 100-300 r / min for 2-3 h to obtain the polyvinyl alcohol solution.

[0030] Preferably, in step (2), the polyvinyl alcohol solution is cooled to 5-40°C, and the wax emulsion, the matt filler, the polyurethane brightener, and the silicone feel agent emulsion are added, and the mixture is continuously stirred at a rotation speed of 100-300 r / min for 0.5-2 h for defoaming, and finally the mixture is filtered and packaged to obtain the leather powder fixing and color fixing agent.

[0031] The present application has the following advantages: 1. Excellent color fixing and powder fixing performance: through the synergistic effect of polyvinyl alcohol and polyurethane, a local film forming effect is formed, the color fixing level can reach 3.5 level, the powder fixing level reaches 3.5 level, which is 1-1.5 levels higher than that of the commercially available products. The hydroxyl group of polyvinyl alcohol is combined with the dye through hydrogen bond, and the isocyanate group of polyurethane is combined with the collagen of leather, and the double effect significantly improves the color fastness.

[0032] 2. Hand feeling and velvet feeling retention: a unique wax emulsion and silicone compound system makes the treated leather maintain soft wax feeling (DOWELLER WAX 5053 and DOWELLFEL F8211 synergistic), and the velvet feeling retention is excellent, solving the problem of hard hand feeling caused by traditional color fixing agent.

[0033] 3. Color stability: light scattering is adjusted by extinction filler (DOWELLER FILLER 4683) and self-extinction polyurethane (DOWELLISH TOP M7228), which effectively avoids the phenomenon of obvious deepening of the treated leather.

[0034] 4. Industrial production advantage: the raw materials are all commercially available products, the process is simple (only two steps of dissolution-mixing), the preparation conditions are mild (below 80℃), no special equipment is needed, and it is suitable for large-scale production.

[0035] 5. Environmental protection characteristics: water-based system without formaldehyde release, in line with relevant regulations, low VOC content. BRIEF DESCRIPTION OF DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiment or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0037] Figure 1 is a color fixing effect comparison chart of example 1, commercially available product 1 and commercially available product 2.

[0038] Figure 2 is a powder fixing effect comparison chart of example 1, commercially available product 1 and commercially available product 2.

[0039] Figure 3 is a color fixing effect comparison chart of example 1 and comparative example 1.

[0040] Figure 4 is a color influence comparison chart of example 1 and comparative example 2. DETAILED DESCRIPTION

[0041] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be described in detail below. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work belong to the scope of protection of the present application.

[0042] Embodiment 1 The present embodiment provides a preparation method of a leather powder fixing and dye fixing agent, which comprises the following steps: (1) Equipment inspection and preparation: check whether the reaction kettle with heat exchange equipment, stirring device, filtering equipment and temperature control system are normally operated, and ensure that the equipment is clean and free of impurities. Avoid the contamination of the raw materials by the residual impurities of the equipment, and ensure the stable reaction environment to provide a reliable equipment foundation for the subsequent preparation process.

[0043] (2) Raw material pretreatment: break the polyvinyl alcohol with a polymerization degree of 1700 and an alcoholysis degree of 88% into particles with a particle size of 5-10 mm; respectively weigh 50 kg of water, 10 kg of pretreated polyvinyl alcohol, 15 kg of DOWELLER WAX 5053 (wax emulsion), 5 kg of DOWELLER FILLER 4683 (matting filler), 10 kg of DOWELLISH TOP M7228 (polyurethane brightener), and 10 kg of DOWELLFEL F8211 (silicone hand agent emulsion), and mark for standby. The broken polyvinyl alcohol can increase the contact area with water and accelerate the dissolution speed; the raw materials are weighed and marked in advance to avoid confusion during feeding and ensure the accurate proportion of the raw materials.

[0044] (3) Polyvinyl alcohol dissolution: add 50 kg of water into the reaction kettle, start the stirring device, and set the rotation speed to 400 r / min. Slowly add the pretreated polyvinyl alcohol particles at room temperature. Adding polyvinyl alcohol at room temperature while stirring can prevent the polyvinyl alcohol from caking due to excessive local concentration and ensure its uniform dispersion in water.

[0045] (4) Temperature rising and dissolution: raise the temperature of the reaction kettle to 80℃, adjust the stirring speed to 200 r / min, and continue stirring for 2 hours. Raising the temperature to 70-90℃ can promote the relaxation of polyvinyl alcohol molecular chains and accelerate the dissolution; reducing the rotation speed to 100-300 r / min can ensure sufficient dissolution and reduce the air bubbles generated by high-speed stirring.

[0046] (5) Temperature reduction treatment: turn off the heating device and let the polyvinyl alcohol solution naturally cool to 30℃, keeping the stirring speed at 200 r / min during the period. Cooling to 5-40℃ provides a suitable temperature environment for the subsequent addition of other raw materials and avoids the destruction of the stability of raw materials such as wax emulsion and silicone hand agent emulsion by high temperature.

[0047] (6) Add other raw materials: add 15 kg of wax emulsion, 5 kg of matting filler, 10 kg of polyurethane brightener, and 10 kg of silicone feel agent emulsion into the reaction kettle in sequence, and stir at a speed of 200 r / min for 1 hour. The raw materials are added in sequence and stirred to uniformly disperse the raw materials in the polyvinyl alcohol solution, forming a stable mixed system.

[0048] (7) Defoaming treatment: reduce the stirring speed to 200 r / min and continue stirring for 15 minutes. Reducing the stirring speed can reduce the generation of new bubbles, and at the same time, the generated bubbles can escape, avoiding the influence of the bubbles on the uniformity of the coating during subsequent use.

[0049] (8) Filtration and packaging: filter the above mixture through a 100-mesh filter screen to remove impurities or undissolved particles that may exist, and then package. Filtration can improve product purity and ensure stable product quality; packaging is convenient for storage, transportation and use.

[0050] Example 2 The embodiment provides a preparation method of a leather powder fixing and color fixing agent. Compared with example 1, the preparation method of example 2 is basically the same, only the selection and ratio of raw materials are different. The preparation method is briefly described as follows: (1) Under the condition of room temperature and stirring speed of 400 r / min, 50 kg of water and 10 kg of polyvinyl alcohol with a polymerization degree of 1700 and alcoholysis degree of 99% are sequentially added into a reaction kettle with heat exchange equipment, then the temperature is raised to 80 DEG C, and stirring and dissolution are performed for 2 hours. After complete dissolution, the temperature is cooled to 30 DEG C, and a polyvinyl alcohol solution is obtained.

[0051] (2) 15 kg of DOWELLER WAX 5053 (wax emulsion), 5 kg of DOWELLER FILLER 4683 (matting filler), 10 kg of DOWELLISH TOP M7228 (polyurethane brightener), and 10 kg of DOWELL FELF8211 (silicone feel agent emulsion) are sequentially added into the reaction kettle, then stirring is performed for 1 hour, the stirring speed is reduced to 200 r / min, defoaming is performed for 15 minutes, and the mixture is filtered and packaged, to obtain the leather powder fixing and color fixing agent.

[0052] Example 3 The embodiment provides a preparation method of a leather powder fixing and color fixing agent. Compared with example 1, the preparation method of example 3 is basically the same, only the selection and ratio of raw materials are different. The preparation method is briefly described as follows: (1) Under the condition of room temperature and stirring speed of 400 r / min, 65 kg of water and 10 kg of polyvinyl alcohol with a polymerization degree of 1700 and alcoholysis degree of 88% were sequentially added into a reaction kettle with heat exchange equipment, then the temperature was raised to 80°C, and stirred and dissolved for 2 hours. After complete dissolution, the temperature was cooled to 30°C to obtain a polyvinyl alcohol solution.

[0053] (2) 5 kg of DOWELLER FILLER 4683 (matting filler), 10 kg of DOWELLISH TOP M7225 (polyurethane brightener), and 10 kg of DOWELLFEL F8211 (silicone hand agent emulsion) were sequentially added into the reaction kettle, then stirred for 1 hour, the stirring speed was reduced to 200 r / min, and stirred for 15 minutes to remove bubbles. After filtration and packaging, the leather powder fixing and color fixing agent was obtained.

[0054] Comparative Example 1 The present comparative example provides a preparation method of a leather powder fixing and color fixing agent, which is briefly described as follows: Under the condition of room temperature and stirring speed of 400 r / min, 60 kg of water was sequentially added into a reaction kettle with heat exchange equipment, then 15 kg of DOWELLER WAX 5053 (wax emulsion), 5 kg of DOWELLER FILLER 4683 (matting filler), 10 kg of DOWELLISH TOP M7225 (polyurethane brightener), and 10 kg of DOWELLFEL F8211 (silicone hand agent emulsion) were sequentially added, then stirred for 1 hour, the stirring speed was reduced to 200 r / min, and stirred for 15 minutes to remove bubbles. After filtration and packaging, the leather powder fixing and color fixing agent was obtained.

[0055] Comparative Example 2 The present comparative example provides a preparation method of a leather powder fixing and color fixing agent, which is briefly described as follows: (1) Under the condition of room temperature and stirring speed of 400 r / min, 50 kg of water and 10 kg of polyvinyl alcohol with a polymerization degree of 1700 and alcoholysis degree of 88% were sequentially added into a reaction kettle with heat exchange equipment, then the temperature was raised to 80°C, and stirred and dissolved for 2 hours. After complete dissolution, the temperature was cooled to 30°C to obtain a polyvinyl alcohol solution.

[0056] (2) 15 kg of DOWELLER WAX 5053 (wax emulsion) and 10 kg of DOWELLFEL F8211 (silicone hand agent emulsion) were sequentially added into the reaction kettle, then stirred for 1 hour, the stirring speed was reduced to 200 r / min, and stirred for 15 minutes to remove bubbles. After filtration and packaging, the leather powder fixing and color fixing agent was obtained.

[0057] Comparative Example 3 The present comparative example provides a preparation method of a leather powder fixing and dye fixing agent, which is briefly described as follows: (1) Under the stirring state of 400 r / min at room temperature, 50 kg of water and 10 kg of polyvinyl alcohol with a polymerization degree of 1700 and an alcoholysis degree of 88% were sequentially added to a reaction kettle with heat exchange equipment, then the temperature was raised to 80°C, and stirred and dissolved for 2 hours. After complete dissolution, it was cooled to 30°C to obtain a polyvinyl alcohol solution.

[0058] (2) 5 kg of DOWELLER FILLER 4683 (matting filler), 10 kg of DOWELLISH TOP M7228 (polyurethane brightener), and 10 kg of DOWELLFEL F8211 (silicone hand agent emulsion) were sequentially added to the reaction kettle, then stirred for 1 hour, the stirring speed was reduced to 200 r / min for 15 minutes to defoam, and then filtered, packaged and discharged, to obtain the leather powder fixing and dye fixing agent.

[0059] Test Example The powder fixing and dye fixing agent prepared in the examples and comparative examples is mainly used for powder fixing and dye fixing of two-layer leather, and has excellent powder fixing and dye fixing performance for leather with long nap, and can impart a waxy and moisturizing feeling to the leather, and has little effect on the color of the leather. The test results are shown in Table 5, and the test pictures are shown in Figures 1-4 .

[0060] Table 5 Performance Example 1 Example 2 Example 3 Commercial product 1 Commercial product 2 Color fixation grade 3.5 3 3.5 1.5 2.5 Powder fixation grade 3.5 3.5 3.5 2 2.5 Hand feeling Soft, waxiness, and moisturizing Soft, waxiness, and moisturizing Relatively soft, dry, and slightly sticky Soft, waxiness, and moisturizing Slightly hard, dry, and slightly sticky Nap retention Good Good Good Good Average Impact on color No significant darkening No significant darkening No significant darkening Significant darkening Significant darkening Table 5 (continued) Performance Comparative example 1 Comparative example 2 Comparative example 3 Color fixation grade 2 3.5 3.5 Powder fixation grade 2 3.5 3.5 Hand feeling Soft, waxiness, and moisturizing Soft, waxiness, and moisturizing Slightly hard, dry, and slightly sticky Nap retention Good Good Average Impact on color No significant darkening Significant darkening No significant darkening Note: (i) The powder fixing and dye fixing grade is 1-5, with 5 being the best and 1 being the worst. The powder fixing and dye fixing grade of the blank leather is 1.

[0061] (ii) Leather: black two-layer suede leather and white two-layer suede leather.

[0062] (iii) Process: After mixing the powder fixing and dye fixing agent with water at a ratio of 1:3, it is sprayed at 2.5-3.0 g / sf, and then dried at 100°C for 2 minutes.

[0063] (iv) Commercial product 1 is LT-36 (trade name), produced by Smith Leather Chemicals Co., Ltd.; and commercial product 2 is PU Adjusting Agent (trade name), produced by Dongguan Taiyang New Material Technology Co., Ltd.

[0064] From the test results, it can be seen that Figure 1 and Figure 2Compared with the commercial product 1, the embodiment of the present application has better fixing effect and less influence on the color of the leather embryo; compared with the commercial product 2, the embodiment of the present application has better fixing effect, better comfortable and moist touch, better retention of the velvet feeling, and less influence on the color of the leather embryo, so the leather powder fixing agent provided by the present application is a multifunctional powder fixing agent product, which has excellent powder fixing effect, can impart oil and wax moist touch to the leather, retain the velvet feeling, and effectively reduce the influence on the color of the leather embryo.

[0065] Compared with example 1, the formula of comparative example 1 lacks polyvinyl alcohol, which leads to a significant decrease in fixing effect, as shown in Table 1. Figure 3 As the main fixing material, polyvinyl alcohol forms discontinuous film on the suede and forms local film effect in microcosm, which prevents dye migration; after forming surface film, the smoothness is increased and the friction coefficient is reduced, which prevents the colored fiber dust from being rubbed off. The hydroxyl groups on the main chain of polyvinyl alcohol polymer can also combine with the un-fixed dye through van der Waals force and hydrogen bond, which improves the binding fastness between the dye and the dye. Therefore, the lack of polyvinyl alcohol will significantly reduce the fixing effect.

[0066] Compared with example 1, the formula of comparative example 2 lacks DOWELLER FILLER 4683 and DOWELLISH TOP M7228, which leads to obvious deepening effect of the leather embryo after spraying, as shown in Table 2. Figure 4 The reason is that the surface polymer exists and the long pile hair is easy to bond after the suede is fixed, so the deepening effect appears, and the self-extinguishing polyurethane resin and the matt filler can effectively adjust the scattering of light, so as to weaken the deepening effect.

[0067] Compared with example 1, the formula of comparative example 3 lacks DOWELLER WAX 5053, which leads to hard touch and lack of wax and moist feeling of comparative example 3. Since polyvinyl alcohol itself forms hard film and has rough touch, it is necessary to combine wax emulsion to soften the touch and impart wax feeling.

[0068] The present application aims to provide a leather fixing and dyeing agent and a preparation method thereof, by using polyvinyl alcohol as the main film-forming material, supplemented by a small amount of polyurethane film-forming, which discontinuously forms a film on the suede, forms a local film effect microscopically, prevents dye migration or leather ash from falling off; and after the surface film is formed, the smoothness is increased, the friction coefficient is reduced, and the colored fiber dust is prevented from being rubbed off. The hydroxyl groups on the polyvinyl alcohol polymer backbone can combine with the unfixed dye through van der Waals force and hydrogen bond, thereby improving the binding fastness between the dye and the dye. The isocyanate in the polyurethane combines with the hydroxyl and carboxyl in the leather collagen to prevent the chromium powder from falling off; after high temperature, the polymer forms crosslinking, inhibits fiber swelling, prevents dye molecules from desorbing from the fiber, and at the same time enhances the strength and wear resistance of the film; the firm combination of the crosslinking structure with the surface of the material can effectively resist the damage of external factors (such as friction, washing, light, etc.) to the dye.

[0069] The fiber surface of the suede is a rough micro surface, on the one hand, the presence of the fixing agent and other chemicals will cause the change of the refractive index of the interface, on the other hand, after the suede is treated with the fixing agent, the long nap appears to be bonded, thereby appearing the deepening effect; by adding self-extinction polyurethane resin and extinction filler to adjust the scattering of light, the deepening effect is effectively weakened.

[0070] The resin film has a dry and rough hand feeling, and the polyvinyl alcohol film alone is hard and has a heavy glue feeling, by adding wax emulsion to increase the wax feeling and moisturizing feeling, the suede feeling is increased.

[0071] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any skilled person in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A leather powder fixing and color fixing agent, characterized by, The raw materials include polyvinyl alcohol 5-20 parts, wax emulsion 10-20 parts, matting filler 3-10 parts, polyurethane brightener 10-20 parts, silicone feel agent emulsion 5-15 parts and water 40-70 parts by weight.

2. The leather fixing and dyeing agent according to claim 1, characterized in that, The raw materials include polyvinyl alcohol 10 parts, wax emulsion 15 parts, matting filler 5 parts, polyurethane brightener 10 parts, silicone feel agent emulsion 10 parts and water 50 parts by weight.

3. The leather fixing and dyeing agent according to claim 1 or 2, characterized in that, The polyvinyl alcohol has a polymerization degree of 500-2500 and an alcoholysis degree of 80-100%.

4. The leather fixing and dyeing agent according to claim 1 or 2, characterized in that, The wax emulsion is one of wood wax emulsion, Fischer-Tropsch wax, polyethylene wax, polypropylene wax, oxidized polyethylene wax and polyamide wax.

5. The leather fixing and dyeing agent according to claim 1 or 2, characterized in that, The matting filler is inorganic matting filler.

6. The leather fixing and dyeing agent according to claim 1 or 2, characterized in that, The polyurethane brightener is water-based polyurethane resin.

7. The leather fixing and dyeing agent according to claim 1 or 2, characterized in that, The silicone feel agent emulsion is one of methyl silicone oil emulsion, methyl hydrogen-containing silicone oil emulsion, amino silicone oil emulsion, epoxy silicone oil emulsion and polyether-modified silicone oil emulsion.

8. The process for the preparation of the leather fixing and colouring agent according to any one of claims 1 to 7, characterized in that, The preparation method includes the following steps: (1) dissolving polyvinyl alcohol in water to obtain a polyvinyl alcohol solution; (2) adding wax emulsion, matting filler, polyurethane brightener and silicone feel agent emulsion to the polyvinyl alcohol solution, stirring and then filtering to obtain the leather powder fixing and dyeing agent.

9. The method for preparing the leather fixing powder and color fixing agent according to claim 1, characterized in that, In step (1), polyvinyl alcohol is added to water at room temperature and a rotation speed of 300-600 r / min, then the temperature is raised to 70-90°C for dissolution, and the solution is stirred at a rotation speed of 100-300 r / min for 2-3 h to obtain the polyvinyl alcohol solution.

10. The method for preparing the leather fixing powder and color fixing agent according to claim 1, characterized in that, In step (2), after the polyvinyl alcohol solution is cooled to 5-40°C, wax emulsion, matting filler, polyurethane brightener and silicone feel agent emulsion are added, and the mixture is continuously stirred at a rotation speed of 100-300 r / min for 0.5-2 h to remove bubbles, and finally the mixture is filtered, packaged and discharged to obtain the leather powder fixing and dyeing agent.

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