A leather product surface treatment agent and preparation method thereof

Abstract

The present invention relates to the technical field of adhesives, and in particular to a leather product surface treatment agent and a preparation method thereof; the leather product surface treatment agent comprises the following raw materials: polyester polyol, epoxy resin, diisocyanate, catalyst, terminator, chlorinated polyethylene, N,N-dimethylformamide, cyclohexanone, calcium stearate and organic solvent; the present invention also provides a preparation method of the leather product surface treatment agent, which enables the surface treatment agent to matte the leather material while maintaining and improving the performance of surface treatment, thereby ensuring a traceless effect on the surface of the leather material.

Description

Technical Field

[0001] The invention relates to the technical field of surface treatment agents, and in particular to a leather product surface treatment agent and a preparation method thereof. Background Art

[0002] Leather products are widely used in clothing, shoes, bags and other products. As the earliest raw material, natural leather has natural ecological characteristics, but with the growth of the world's population and the rapid development of the economy, natural leather can no longer meet people's needs.

[0003] Artificial leather made by foaming or laminating PU and PVC can be processed by adding additives such as pigments, plasticizers, toughening agents, etc. according to different strength, color, gloss, pattern and other requirements. It has the characteristics of a wide variety of colors, good waterproof performance, neat edges, high utilization rate and relatively low price compared to genuine leather. However, the addition of a large amount of plasticizers and toughening agents makes the adhesion between the adhesive and PU and PVC leather low, and it is easy to debond. Usually in the shoemaking industry, in order to improve the bonding strength, it is often necessary to surface treat the adhesive material. However, since PU and PVC leather are soft and thin, it is difficult to polish the surface, so surface treatment agents are often used for surface treatment. However, when the existing surface treatment agents are used on PU and PVC leather without polishing, the surface will reflect light and have traces. Summary of the invention

[0004] In order to meet the purpose of maintaining surface treatment properties and the like while achieving matte and tracelessness of leather product surface treatment agents, the first object of the present invention is to provide a leather product surface treatment agent, comprising the following raw material components: polyester polyol, epoxy resin, diisocyanate, catalyst, terminator, chlorinated polyethylene, N,N-dimethylformamide, cyclohexanone, calcium stearate and organic solvent.

[0005] Preferably, the following raw materials are included in percentage by weight: polyester polyol: 10-15 parts, epoxy resin: 5-10 parts, diisocyanate: 0.9-1.2 parts; catalyst: 0.06-0.1 parts; terminator: 0.04-0.07 parts; chlorinated polyethylene: 5-8 parts; N,N-dimethylformamide: 60-80 parts; cyclohexanone: 65-90 parts; calcium stearate: 1-3 parts; organic solvent: 370-490 parts.

[0006] Preferably, the polyester polyol:the epoxy resin=1.5:1.

[0007] Preferably, the sum of the polyester polyol and the epoxy resin: chlorinated polyethylene = 3:1.

[0008] Preferably, the molecular weight of the polyester polyol is 2900-3100, to prevent the molecular weight of the polyester polyol from being too low, which may result in poor heat resistance, or the molecular weight of the polyester polyol from being too high, which may result in difficulty in reaction or slow reaction rate.

[0009] Preferably, the epoxy resin is E-20 or E-21.

[0010] Preferably, the catalyst is dibutyltin dilaurate.

[0011] Preferably, the terminator is ethylene glycol.

[0012] Preferably, the organic solvent is butanone and toluene, the butanone is 215 parts to 295 parts, and the toluene is 155 parts to 195 parts.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] (1) Using diisocyanate as a crosslinking agent, it reacts with the hydroxyl groups in polyester polyol and epoxy resin to form a polyurethane structure. The crosslinked polymer has a small molecular weight and is easy to diffuse. Because of its high reactivity, it is easy to form a crosslinked structure with the surface of the leather material, thereby improving the bonding effect of the surface treatment agent for leather products.

[0015] (2) Since the structure of chlorinated polyethylene is similar to that of PVC material, the chlorine element contained in chlorinated polyethylene can destroy the chemical bonds on the surface of PVC material, activate the properties, and greatly improve the adhesion of the surface treatment agent.

[0016] (3) The molecular structure of calcium stearate enables it to have good dispersibility in the polymer matrix. It can be evenly dispersed in the polymer to form a fine granular structure. This dispersion effect can scatter light, thereby reducing the gloss of the material. At the same time, calcium stearate can adsorb light, causing it to scatter when it propagates in the material. This scattering will cause the propagation path of light in the material to become complicated, resulting in a matte effect on the surface of the material. Therefore, calcium stearate, as a matting agent, can enable the surface treatment agent to matte the leather material, ensuring a traceless effect on the leather surface.

[0017] The second object of the present invention is to provide a technical solution: a method for preparing a leather product surface treatment agent, comprising the following steps:

[0018] Step (1): adding part of the organic solvent, polyester polyol and epoxy resin into a reaction kettle in sequence, mixing, stirring and dissolving at 50° C. at a stirring speed of 400 rpm for 1.5-2.5 hours to obtain a mixture A;

[0019] Step (2): After the temperature of the reaction kettle is heated to 90° C., the diisocyanate and the catalyst are added to the mixture A in sequence, and the mixture is stirred at 90° C. at a stirring speed of 60 rpm. When the viscosity begins to thicken continuously, samples are taken every half an hour to obtain an infrared spectrum. When the infrared spectrum no longer changes, the reaction is deemed to be complete, and stirring is stopped to obtain a mixture B;

[0020] Step (3): After adding the terminator to the mixture B, stop heating, then add the organic solvent, chlorinated polyethylene, N,N-dimethylformamide, cyclohexanone and calcium stearate, and stir at a stirring speed of 200 rpm for 1.5-2.5 hours to obtain a mixture C;

[0021] Step (4): adding part of the organic solvent to the mixture C, adjusting the solid content of the mixture C to the product requirements, and obtaining a leather product surface treatment agent.

[0022] Preferably, part of the organic solvent in step (1) is toluene, the organic solvent in step (3) is toluene and butanone, and part of the organic solvent in step (4) is butanone.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) In step (1), the polyester polyol and the epoxy resin are first stirred and dissolved by toluene. Since toluene has good solubility in polyester polyol and epoxy resin, the dissolution effect of toluene on polyester polyol and epoxy resin can be enhanced, and the polyester polyol and epoxy resin can be more fully involved in the reaction in the subsequent steps.

[0025] (2) In step (2), diisocyanate and catalyst dibutyltin dilaurate are added. Dibutyltin dilaurate is a highly active organic tin catalyst that can effectively promote a variety of organic reactions, accelerate the reaction rate, and improve the reaction efficiency, so that the diisocyanate can fully cross-link with the polyester polyol and the epoxy resin.

[0026] (3) In step (4), butanone and ethyl acetate organic solvents are added to reduce the boiling point of the entire system due to their low boiling points, thereby accelerating the volatilization of solvents such as toluene in the adhesive.

[0027] (4) In the preparation method, the polyester polyol and the epoxy resin are first fully dissolved, and then the diisocyanate and the catalyst are added to carry out a cross-linking reaction. After a certain degree of reaction, a polymer with a certain molecular weight is obtained, and then a terminator is added to carry out a termination reaction to prevent the continued growth of the polymerization chain, thereby controlling the molecular weight and distribution of the polymer; then an organic solvent, chlorinated polyethylene, N,N-dimethylformamide and cyclohexanone are added to improve its adhesion and aging resistance; calcium stearate is added to make it have a matte property; finally, the solid content is adjusted by butanone to meet the solid content requirements.

[0028] (5) This preparation method only involves constant temperature stirring, dissolution and other processes, and the process flow is simple. DETAILED DESCRIPTION

[0029] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0030] Before further describing the specific embodiments of the present invention, it should be understood that the scope of protection of the present invention is not limited to the specific embodiments described below; it should also be understood that the terms used in the examples of the present invention are for describing specific embodiments rather than for limiting the scope of protection of the present invention.

[0031] When the embodiment gives a numerical range, it should be understood that, unless otherwise specified in the present invention, the two endpoints of each numerical range and any numerical value between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used herein have the same meanings as those of ordinary skill in the art to which the present invention belongs.

[0032] The present invention does not limit the source of raw materials. Unless otherwise specified, the raw materials used are common commercial products.

[0033] Embodiment 1:

[0034] The surface treatment agent for leather products comprises the following raw materials, calculated by weight percentage: polyester polyol (molecular weight 3000): 15 parts, epoxy resin E-21: 10 parts, diisocyanate: 1.2 parts; dibutyltin dilaurate: 0.1 parts; ethylene glycol: 0.07 parts; chlorinated polyethylene: 8 parts; N, N-dimethylformamide: 80 parts; cyclohexanone: 90 parts; calcium stearate: 2 parts; butanone: 295 parts; toluene: 195 parts;

[0035] The preparation method of the leather product surface treatment agent comprises the following specific steps:

[0036] Step (1): adding toluene, polyester polyol and epoxy resin into a reaction kettle in sequence, mixing, stirring and dissolving at 50° C. at a stirring speed of 400 rpm for 2.5 h to obtain a mixture A;

[0037] Step (2): After the temperature of the reaction kettle is heated to 90° C., the diisocyanate and the catalyst are added to the mixture A in sequence, and the mixture is stirred at 90° C. at a stirring speed of 60 rpm. When the viscosity begins to thicken continuously, samples are taken every half an hour to obtain an infrared spectrum. When the infrared spectrum no longer changes, the reaction is deemed to be complete, and stirring is stopped to obtain a mixture B;

[0038] Step (3): After adding the terminator to the mixture B, stop heating, then add toluene, butanone, chlorinated polyethylene, N,N-dimethylformamide, cyclohexanone and calcium stearate, stir at a stirring speed of 200 rpm for 2.5 hours to obtain a mixture C;

[0039] Step (4): adding butanone to mixture C, adjusting the solid content of mixture C to product requirements, and obtaining a leather product surface treatment agent.

[0040] Embodiment 2:

[0041] The surface treatment agent for leather products comprises the following raw materials, calculated by weight percentage: polyester polyol (molecular weight 2900): 10 parts, epoxy resin E-20: 7 parts, diisocyanate: 0.9 parts; dibutyltin dilaurate: 0.06 parts; ethylene glycol: 0.04 parts; chlorinated polyethylene: 6 parts; N, N-dimethylformamide: 60 parts; cyclohexanone: 65 parts; calcium stearate: 1.5 parts; butanone: 215 parts; toluene: 155 parts;

[0042] The preparation method of the leather product surface treatment agent comprises the following specific steps:

[0043] Step (1): adding toluene, polyester polyol and epoxy resin into a reaction kettle in sequence, mixing, stirring and dissolving at 50° C. at a stirring speed of 400 rpm for 1.5 hours to obtain a mixture A;

[0044] Step (2): After the temperature of the reaction kettle is heated to 90° C., the diisocyanate and the catalyst are added to the mixture A in sequence, and the mixture is stirred at 90° C. at a stirring speed of 60 rpm. When the viscosity begins to thicken continuously, samples are taken every half an hour to obtain an infrared spectrum. When the infrared spectrum no longer changes, the reaction is deemed to be complete, and stirring is stopped to obtain a mixture B;

[0045] Step (3): After adding the terminator to the mixture B, stop heating, then add toluene, butanone, chlorinated polyethylene, N,N-dimethylformamide, cyclohexanone and calcium stearate, stir and react at a stirring speed of 200 rpm for 1.5 hours to obtain a mixture C;

[0046] Step (4): adding butanone to mixture C, adjusting the solid content of mixture C to product requirements, and obtaining a leather product surface treatment agent.

[0047] Embodiment 3:

[0048] The surface treatment agent for leather products comprises the following raw materials, calculated by weight percentage: polyester polyol (molecular weight 3100): 12 parts, epoxy resin E-21: 8 parts, diisocyanate: 1.0 parts; dibutyltin dilaurate: 0.08 parts; ethylene glycol: 0.05 parts; chlorinated polyethylene: 7 parts; N, N-dimethylformamide: 70 parts; cyclohexanone: 75 parts; calcium stearate: 1.6 parts; butanone: 255 parts; toluene: 175 parts;

[0049] The preparation method of the leather product surface treatment agent comprises the following specific steps:

[0050] Step (1): adding toluene, polyester polyol and epoxy resin into a reaction kettle in sequence, mixing, stirring and dissolving at 50° C. at a stirring speed of 400 rpm for 2 hours to obtain a mixture A;

[0051] Step (2): After the temperature of the reaction kettle is heated to 90° C., the diisocyanate and the catalyst are added to the mixture A in sequence, and the mixture is stirred at 90° C. at a stirring speed of 60 rpm. When the viscosity begins to thicken continuously, samples are taken every half an hour to obtain an infrared spectrum. When the infrared spectrum no longer changes, the reaction is deemed to be complete, and stirring is stopped to obtain a mixture B;

[0052] Step (3): After adding the terminator to the mixture B, stop heating, then add toluene, butanone, chlorinated polyethylene, N,N-dimethylformamide, cyclohexanone and calcium stearate, stir and react at a stirring speed of 200 rpm for 2 hours to obtain a mixture C;

[0053] Step (4): adding butanone to mixture C, adjusting the solid content of mixture C to product requirements, and obtaining a leather product surface treatment agent.

[0054] Embodiment 4:

[0055] The surface treatment agent for leather products comprises the following raw materials, calculated by weight percentage: polyester polyol (molecular weight 3000): 5 parts, epoxy resin E-21: 10 parts, diisocyanate: 1.2 parts; dibutyltin dilaurate: 0.1 parts; ethylene glycol: 0.07 parts; chlorinated polyethylene: 8 parts; N, N-dimethylformamide: 80 parts; cyclohexanone: 90 parts; calcium stearate: 3 parts; butanone: 295 parts; toluene: 195 parts;

[0056] The preparation method of the leather product surface treatment agent comprises the following specific steps:

[0057] Step (1): adding toluene, polyester polyol and epoxy resin into a reaction kettle in sequence, mixing, stirring and dissolving at 50° C. at a stirring speed of 400 rpm for 2.5 h to obtain a mixture A;

[0058] Step (2): After the temperature of the reaction kettle is heated to 90° C., the diisocyanate and the catalyst are added to the mixture A in sequence, and the mixture is stirred at 90° C. at a stirring speed of 60 rpm. When the viscosity begins to thicken continuously, samples are taken every half an hour to obtain an infrared spectrum. When the infrared spectrum no longer changes, the reaction is deemed to be complete, and stirring is stopped to obtain a mixture B;

[0059] Step (3): After adding the terminator to the mixture B, stop heating, then add toluene, butanone, chlorinated polyethylene, N,N-dimethylformamide, cyclohexanone and calcium stearate, stir at a stirring speed of 200 rpm for 2.5 hours to obtain a mixture C;

[0060] Step (4): adding butanone to mixture C, adjusting the solid content of mixture C to product requirements, and obtaining a leather product surface treatment agent.

[0061] Embodiment 5:

[0062] The surface treatment agent for leather products comprises the following raw materials, calculated by weight percentage: polyester polyol (molecular weight 3000): 10 parts, epoxy resin E-21: 10 parts, diisocyanate: 1.2 parts; dibutyltin dilaurate: 0.1 parts; ethylene glycol: 0.07 parts; chlorinated polyethylene: 8 parts; N, N-dimethylformamide: 80 parts; cyclohexanone: 90 parts; calcium stearate: 1.5 parts; butanone: 295 parts; toluene: 195 parts;

[0063] The preparation method of the leather product surface treatment agent comprises the following specific steps:

[0064] Step (1): adding toluene, polyester polyol and epoxy resin into a reaction kettle in sequence, mixing, stirring and dissolving at 50° C. at a stirring speed of 400 rpm for 2.5 h to obtain a mixture A;

[0065] Step (2): After the temperature of the reaction kettle is heated to 90° C., the diisocyanate and the catalyst are added to the mixture A in sequence, and the mixture is stirred at 90° C. at a stirring speed of 60 rpm. When the viscosity begins to thicken continuously, samples are taken every half an hour to obtain an infrared spectrum. When the infrared spectrum no longer changes, the reaction is deemed to be complete, and stirring is stopped to obtain a mixture B;

[0066] Step (3): After adding the terminator to the mixture B, stop heating, then add toluene, butanone, chlorinated polyethylene, N,N-dimethylformamide, cyclohexanone and calcium stearate, stir at a stirring speed of 200 rpm for 2.5 hours to obtain a mixture C;

[0067] Step (4): adding butanone to mixture C, adjusting the solid content of mixture C to product requirements, and obtaining a leather product surface treatment agent.

[0068] Embodiment 6:

[0069] The surface treatment agent for leather products comprises the following raw materials, calculated by weight percentage: polyester polyol (molecular weight 3000): 10 parts, epoxy resin E-21: 5 parts, diisocyanate: 1.2 parts; dibutyltin dilaurate: 0.1 parts; ethylene glycol: 0.07 parts; chlorinated polyethylene: 8 parts; N, N-dimethylformamide: 80 parts; cyclohexanone: 90 parts; calcium stearate: 1 part; butanone: 295 parts; toluene: 195 parts;

[0070] The preparation method of the leather product surface treatment agent comprises the following specific steps:

[0071] Step (1): adding toluene, polyester polyol and epoxy resin into a reaction kettle in sequence, mixing, stirring and dissolving at 50° C. at a stirring speed of 400 rpm for 2.5 h to obtain a mixture A;

[0072] Step (2): After the temperature of the reaction kettle is heated to 90° C., the diisocyanate and the catalyst are added to the mixture A in sequence, and the mixture is stirred at 90° C. at a stirring speed of 60 rpm. When the viscosity begins to thicken continuously, samples are taken every half an hour to obtain an infrared spectrum. When the infrared spectrum no longer changes, the reaction is deemed to be complete, and stirring is stopped to obtain a mixture B;

[0073] Step (3): After adding the terminator to the mixture B, stop heating, then add toluene, butanone, chlorinated polyethylene, N,N-dimethylformamide, cyclohexanone and calcium stearate, stir at a stirring speed of 200 rpm for 2.5 hours to obtain a mixture C;

[0074] Step (4): adding butanone to mixture C, adjusting the solid content of mixture C to product requirements, and obtaining a leather product surface treatment agent.

[0075] Embodiment 7:

[0076] The surface treatment agent for leather products comprises the following raw materials, calculated by weight percentage: polyester polyol (molecular weight 3000): 15 parts, epoxy resin E-21: 6 parts, diisocyanate: 1.2 parts; dibutyltin dilaurate: 0.1 parts; ethylene glycol: 0.07 parts; chlorinated polyethylene: 8 parts; N, N-dimethylformamide: 80 parts; cyclohexanone: 90 parts; calcium stearate: 2 parts; butanone: 295 parts; toluene: 195 parts;

[0077] The preparation method of the leather product surface treatment agent comprises the following specific steps:

[0078] Step (1): adding toluene, polyester polyol and epoxy resin into a reaction kettle in sequence, mixing, stirring and dissolving at 50° C. at a stirring speed of 400 rpm for 2.5 h to obtain a mixture A;

[0079] Step (2): After the temperature of the reaction kettle is heated to 90° C., the diisocyanate and the catalyst are added to the mixture A in sequence, and the mixture is stirred at 90° C. at a stirring speed of 60 rpm. When the viscosity begins to thicken continuously, samples are taken every half an hour to obtain an infrared spectrum. When the infrared spectrum no longer changes, the reaction is deemed to be complete, and stirring is stopped to obtain a mixture B;

[0080] Step (3): After adding the terminator to the mixture B, stop heating, then add toluene, butanone, chlorinated polyethylene, N,N-dimethylformamide, cyclohexanone and calcium stearate, stir at a stirring speed of 200 rpm for 2.5 hours to obtain a mixture C;

[0081] Step (4): adding butanone to mixture C, adjusting the solid content of mixture C to product requirements, and obtaining a leather product surface treatment agent.

[0082] Embodiment 8:

[0083] The surface treatment agent for leather products comprises the following raw materials by weight percentage: polyester polyol (molecular weight 3000): 15 parts, epoxy resin E-21: 10 parts, diisocyanate: 1.2 parts; dibutyltin dilaurate: 0.1 parts; ethylene glycol: 0.07 parts; chlorinated polyethylene: 25 parts; N, N-dimethylformamide: 80 parts; cyclohexanone: 90 parts; calcium stearate: 2 parts; butanone: 295 parts; toluene: 195 parts;

[0084] The preparation method of the leather product surface treatment agent comprises the following specific steps:

[0085] Step (1): adding toluene, polyester polyol and epoxy resin into a reaction kettle in sequence, mixing, stirring and dissolving at 50° C. at a stirring speed of 400 rpm for 2.5 h to obtain a mixture A;

[0086] Step (2): After the temperature of the reaction kettle is heated to 90° C., the diisocyanate and the catalyst are added to the mixture A in sequence, and the mixture is stirred at 90° C. at a stirring speed of 60 rpm. When the viscosity begins to thicken continuously, samples are taken every half an hour to obtain an infrared spectrum. When the infrared spectrum no longer changes, the reaction is deemed to be complete, and stirring is stopped to obtain a mixture B;

[0087] Step (3): After adding the terminator to the mixture B, stop heating, then add toluene, butanone, chlorinated polyethylene, N,N-dimethylformamide, cyclohexanone and calcium stearate, stir at a stirring speed of 200 rpm for 2.5 hours to obtain a mixture C;

[0088] Step (4): adding butanone to mixture C, adjusting the solid content of mixture C to product requirements, and obtaining a leather product surface treatment agent.

[0089] Embodiment 9:

[0090] The surface treatment agent for leather products comprises the following raw materials, calculated by weight percentage: polyester polyol (molecular weight 3000): 15 parts, epoxy resin E-21: 10 parts, diisocyanate: 1.2 parts; dibutyltin dilaurate: 0.1 parts; ethylene glycol: 0.07 parts; chlorinated polyethylene: 12.5 parts; N, N-dimethylformamide: 80 parts; cyclohexanone: 90 parts; calcium stearate: 2 parts; butanone: 295 parts; toluene: 195 parts;

[0091] The preparation method of the leather product surface treatment agent comprises the following specific steps:

[0092] Step (1): adding toluene, polyester polyol and epoxy resin into a reaction kettle in sequence, mixing, stirring and dissolving at 50° C. at a stirring speed of 400 rpm for 2.5 h to obtain a mixture A;

[0093] Step (2): After the temperature of the reaction kettle is heated to 90° C., the diisocyanate and the catalyst are added to the mixture A in sequence, and the mixture is stirred at 90° C. at a stirring speed of 60 rpm. When the viscosity begins to thicken continuously, samples are taken every half an hour to obtain an infrared spectrum. When the infrared spectrum no longer changes, the reaction is deemed to be complete, and stirring is stopped to obtain a mixture B;

[0094] Step (3): After adding the terminator to the mixture B, stop heating, then add toluene, butanone, chlorinated polyethylene, N,N-dimethylformamide, cyclohexanone and calcium stearate, stir at a stirring speed of 200 rpm for 2.5 hours to obtain a mixture C;

[0095] Step (4): adding butanone to mixture C, adjusting the solid content of mixture C to product requirements, and obtaining a leather product surface treatment agent.

[0096] Embodiment 10:

[0097] The surface treatment agent for leather products comprises the following raw materials, calculated by weight percentage: polyester polyol (molecular weight 3000): 15 parts, epoxy resin E-21: 10 parts, diisocyanate: 1.2 parts; dibutyltin dilaurate: 0.1 parts; ethylene glycol: 0.07 parts; chlorinated polyethylene: 6 parts; N, N-dimethylformamide: 80 parts; cyclohexanone: 90 parts; calcium stearate: 2 parts; butanone: 295 parts; toluene: 195 parts;

[0098] The preparation method of the leather product surface treatment agent comprises the following specific steps:

[0099] Step (1): adding toluene, polyester polyol and epoxy resin into a reaction kettle in sequence, mixing, stirring and dissolving at 50° C. at a stirring speed of 400 rpm for 2.5 h to obtain a mixture A;

[0100] Step (2): After the temperature of the reaction kettle is heated to 90° C., the diisocyanate and the catalyst are added to the mixture A in sequence, and the mixture is stirred at 90° C. at a stirring speed of 60 rpm. When the viscosity begins to thicken continuously, samples are taken every half an hour to obtain an infrared spectrum. When the infrared spectrum no longer changes, the reaction is deemed to be complete, and stirring is stopped to obtain a mixture B;

[0101] Step (3): After adding the terminator to the mixture B, stop heating, then add toluene, butanone, chlorinated polyethylene, N,N-dimethylformamide, cyclohexanone and calcium stearate, stir at a stirring speed of 200 rpm for 2.5 hours to obtain a mixture C;

[0102] Step (4): adding butanone to mixture C, adjusting the solid content of mixture C to product requirements, and obtaining a leather product surface treatment agent.

[0103] Embodiment 11:

[0104] The surface treatment agent for leather products comprises the following raw materials by weight percentage: polyester polyol (molecular weight 3000): 15 parts, epoxy resin E-21: 10 parts, diisocyanate: 1.2 parts; dibutyltin dilaurate: 0.1 parts; ethylene glycol: 0.07 parts; chlorinated polyethylene: 5 parts; N, N-dimethylformamide: 80 parts; cyclohexanone: 90 parts; calcium stearate: 2 parts; butanone: 295 parts; toluene: 195 parts;

[0105] The preparation method of the leather product surface treatment agent comprises the following specific steps:

[0106] Step (1): adding toluene, polyester polyol and epoxy resin into a reaction kettle in sequence, mixing, stirring and dissolving at 50° C. at a stirring speed of 400 rpm for 2.5 h to obtain a mixture A;

[0107] Step (2): After the temperature of the reaction kettle is heated to 90° C., the diisocyanate and the catalyst are added to the mixture A in sequence, and the mixture is stirred at 90° C. at a stirring speed of 60 rpm. When the viscosity begins to thicken continuously, samples are taken every half an hour to obtain an infrared spectrum. When the infrared spectrum no longer changes, the reaction is deemed to be complete, and stirring is stopped to obtain a mixture B;

[0108] Step (3): After adding the terminator to the mixture B, stop heating, then add toluene, butanone, chlorinated polyethylene, N,N-dimethylformamide, cyclohexanone and calcium stearate, stir at a stirring speed of 200 rpm for 2.5 hours to obtain a mixture C;

[0109] Step (4): adding butanone to mixture C, adjusting the solid content of mixture C to product requirements, and obtaining a leather product surface treatment agent.

[0110] Some samples of the leather product surface treatment agent prepared in Examples 1 to 11 were taken as samples 1-11, and applied to shoe materials to test their initial adhesion, peel strength, temperature difference resistance, aging resistance and hydrolysis resistance.

[0111] The initial viscosity is determined according to the method specified in GB / T 19340-2014.

[0112] The peel strength is determined according to the method specified in GB / T 19340-2014 for peel strength;

[0113] The shear strength is determined according to the method specified in GB / T 19340-2014 for shear strength;

[0114] The yellowing resistance test is carried out according to the standard test piece prepared in GB / T 19340-2014. The test condition is 50℃×48H, and the yellowing degree is observed. The yellowing grade is 1-4, which means poor to excellent.

[0115] The extinction performance was determined by observing the standard test pieces prepared in GB / T 19340-2014 under natural environment.

[0116] Table 1 shows the test data of initial adhesion, peel strength, shear strength and yellowing resistance of samples 1-11.

[0117] Table 1

[0118]

[0119] It can be seen from the data in Table 1 that the leather product surface treatment agent prepared by this method has good initial adhesion and peel strength performance for shoe materials, significantly improves the shear strength, and has excellent yellowing resistance. It can matte the leather material to ensure a seamless effect on the surface of the leather material.

[0120] From the comparison of Examples 1-7, it can be seen that, when other conditions are the same, as the ratio of polyester polyol to epoxy resin increases, the treatment effect of the treatment agent on PU and PVC leather becomes better, the effect is best when the ratio is 1.5, and the effect begins to weaken when the ratio is greater than 1.5.

[0121] By comparing Example 1 with Examples 8-11, it can be seen that, when other conditions are the same, as the ratio of the polymer formed by polyester polyol and epoxy resin to chlorinated polyethylene increases, the treatment effect of the treating agent on PU and PVC leather becomes better, and the effect is best when the ratio is 3:1, and the effect begins to weaken when the ratio is greater than 3:1.

[0122] From the comparison of Examples 1-11, it can be seen that calcium stearate is added in the present application, and the different contents thereof will affect the matting performance of the system. The calcium stearate content in Example 6 is 0.1%, the calcium stearate content in Example 5 is 0.2%, the calcium stearate content in Examples 1-3 and Examples 7-11 is 0.3%, and the calcium stearate content in Example 4 is 0.4%. It can be seen from the data in Table 1 that when the calcium stearate content reaches 0.3%, the matting performance is the best. When the calcium stearate content reaches more than 0.4%, the calcium stearate cannot be completely dissolved, resulting in the precipitation of calcium stearate.

[0123] Therefore, diisocyanate is used as a cross-linking agent, and reacts with the hydroxyl groups in polyester polyol and the hydroxyl groups in epoxy resin to form a polyurethane structure through cross-linking. The cross-linked polymer has a small molecular weight and is easy to diffuse. Because of its high reactivity, it is easy to form a cross-linked structure with the surface of the leather material, thereby improving the adhesion effect of the surface treatment agent for leather products. By adding calcium stearate as a matting agent, the surface treatment agent can matte the leather material to ensure a traceless effect on the surface of the leather material.

[0124] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A surface treatment agent for leather products, characterized in that: Including the following raw materials: By weight, including the following raw materials: Polyester polyol: 10-15 parts, epoxy resin: 5-10 parts, diisocyanate: 0.9-1.2 parts; Catalyst: 0.06-0.1 parts; Terminator: 0.04-0.07 parts; Chlorinated polyethylene: 5-8 parts; N,N-dimethylformamide: 60-80 parts; Cyclohexanone: 65 parts to 90 parts; calcium stearate: 1 part to 3 parts; organic solvent: 370 parts to 490 parts; wherein the polyester polyol: the epoxy resin = 1.5:

1.

2. The leather product surface treatment agent according to claim 1, characterized in that: The sum of the polyester polyol and the epoxy resin: chlorinated polyethylene = 3:

1.

3. The leather product surface treatment agent according to claim 1, characterized in that: The molecular weight of the polyester polyol is 2900-3100.

4. The leather product surface treatment agent according to claim 1, characterized in that: The epoxy resin is E-20 or E-21.

5. The leather product surface treatment agent according to claim 1, characterized in that: The catalyst is dibutyltin dilaurate.

6. The leather product surface treatment agent according to claim 1, characterized in that: The terminator is ethylene glycol.

7. The leather product surface treatment agent according to claim 1, characterized in that: The organic solvent is butanone and toluene, wherein the butanone is 215 parts to 295 parts, and the toluene is 155 parts to 195 parts.

8. A method for preparing the leather product surface treatment agent according to any one of claims 1 to 7, characterized in that: The following steps are involved: Step (1): adding part of the organic solvent, polyester polyol and epoxy resin into a reaction kettle in sequence, mixing, stirring and dissolving at 50° C. at a stirring speed of 400 rpm for 1.5-2.5 hours to obtain a mixture A; Step (2): After heating the temperature of the reaction kettle to 90°C, add the diisocyanate and the catalyst to the mixture A in sequence, and stir at 90°C at a stirring speed of 60 rpm. When the viscosity starts to thicken continuously, take a sample every half an hour to take an infrared spectrum. When the infrared spectrum no longer changes, the reaction is considered to be complete, and stirring is stopped to add the mixture B; Step (3): After adding the terminator to the mixture B, stop heating, then add an organic solvent, chlorinated polyethylene, N,N-dimethylformamide, cyclohexanone and calcium stearate, and stir at a stirring speed of 200 rpm for 1.5-2.5 hours to obtain a mixture C; Step (4): adding part of the organic solvent to the mixture C, adjusting the solid content of the mixture C to the product requirements, and obtaining a leather product surface treatment agent.

9. The method for preparing the leather product surface treatment agent according to claim 8, characterized in that: Part of the organic solvent in step (1) is toluene, part of the organic solvent in step (3) is toluene and butanone, and part of the organic solvent in step (4) is butanone.

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