Aqueous polyurethane for surface treatment, preparation method and application thereof

Abstract

The invention provides a water-based polyurethane for a surfactant and a preparation method and application thereof. The water-based polyurethane for a surfactant comprises an A component, a B component, a post-chain extender and a solvent. The A component and the B component have different types of polyols and different types of isocyanates, so that two polymers formed thereby have different softness and hardness. Furthermore, the contents of the hydrophilic chain extender are different, so that the sizes of nanoparticles of the two polymers formed thereby are different. Finally, a method of blending and post-chain extension is used to obtain a water-based polyurethane for a surfactant with comprehensive properties such as good anti-fouling effect and skin feel effect, so as to well solve the problem that the current water-based bulk matting resin has special fog and special black properties but is difficult to store stably.

Description

Technical Field

[0001] The invention belongs to the technical field of polyurethane, and in particular relates to a water-based polyurethane for a surface treatment agent and a preparation method and application thereof. Background Art

[0002] With the change of people's aesthetic concepts and the continuous improvement of living standards, people are paying more and more attention to matting materials. Matting materials, with their elegant and natural characteristics, have been widely used in all aspects of daily life, such as leather, paper, coatings, etc. There are many methods for preparing matting materials, which are mainly divided into physical methods and chemical methods. The physical method is to add a matting agent (such as high filler, micro wax powder, inorganic matting powder, organic matting resin filler, etc.) to the resin to achieve the purpose of matting. This physical matting method can achieve a good matting effect, but the disadvantages are also obvious. The addition of matting aids will make the emulsion difficult to store due to the addition of matting agents, and the mechanical strength is poor. Chemical matting is mainly to synthesize high-resolution materials with specific structures through chemical reactions, and use the relationship between its structure and properties or the differences in the properties of each component in the material to achieve the matting effect of the material without the need for an external matting agent. Bulk matte polyurethane dispersion is a common matte resin prepared by chemical methods. It uses water as the dispersion medium without adding any matte agent. After drying and forming a film, it forms an uneven surface to achieve a matte effect. Compared with physical matte polyurethane, it has the advantages of being green, environmentally friendly, and high-performance. Bulk matte waterborne polyurethane (WPU) can effectively improve the defects of adding matte agents, and with the strengthening of people's environmental awareness and the introduction of environmental protection policies by the state, it will become a trend for bulk matte waterborne polyurethane to replace physical matte polyurethane.

[0003] In the synthetic leather industry, the special fog black effect is a new style loved by the majority of consumers. However, the polyurethane used in the special fog black surface treatment agent on the market is mainly oily, which is not pollution-free. Some water-based special fog black surface treatment agents are added with a large amount of matting powder, which leads to poor storage stability of the emulsion. Precipitation will occur after long-term storage and it cannot be used.

[0004] Therefore, it is urgent to synthesize and prepare an environmentally friendly, self-matting, special fog, special black and stable performance synthetic leather surface treatment agent. Summary of the invention

[0005] The purpose of the present invention is to provide an aqueous polyurethane for a surfactant and a preparation method and application thereof, so as to solve the problems of difficult storage stability and easy pollution of the current surfactant.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A water-based polyurethane for a surfactant, comprising component A, component B, a post-chain extender and a solvent, wherein:

[0008] In parts by mass, the component A comprises: polyester polyol, 17.1-18.55 parts; silicone polyol, 1-1.52 parts; first diisocyanate, 8-9.3 parts; first small molecule chain extender, 0.17-0.35 parts; hydrophilic chain extender, 0.31-0.55 parts; neutralizer, 0.13-0.35 parts; deionized water, 69.5-70.5 parts;

[0009] In parts by mass, the B component includes: polyether polyol, 17.1-20.55 parts; silicone polyol, 1-1.52 parts; second diisocyanate, 6.05-9.3 parts; first small molecule chain extender, 0.17-0.35 parts; hydrophilic chain extender, 0.57-0.82 parts; neutralizer, 0.39-0.67 parts; deionized water, 69.5-70.5 parts. Optionally, the polyester polyol is one of polycarbonate diol and polycaprolactone diol or a mixture of two thereof, and the number average molecular weight of the polyester polyol is 1000-2000 g / mol;

[0010] The polyether polyol is one or a mixture of polytetrahydrofuran diol and polyoxypropylene diol, and the number average molecular weight of the polyether polyol is 1000-2000 g / mol;

[0011] The organosilicon polyol is an organosilicon diol with a side chain, and the number average molecular weight of the organosilicon polyol is 1000-2000 g / mol.

[0012] Optionally, the first diisocyanate is 4,4'-dicyclohexylmethane diisocyanate;

[0013] The second diisocyanate is one or a mixture of isophorone diisocyanate and hexamethylene diisocyanate;

[0014] The first small molecule chain extender is one of trimethylolpropane and trimethylolethane or a mixture of the two;

[0015] The hydrophilic chain extender is one of dimethylol propionic acid and dimethylol butyric acid or a mixture of the two;

[0016] The neutralizing agent is triethylamine or potassium hydroxide.

[0017] Optionally, the component A further comprises, by weight: 0.71-0.95 parts of a second small molecule chain extender; 0.05-0.07 parts of a catalyst;

[0018] In parts by mass, the B component further comprises: 0.71-0.85 parts of a second small molecule chain extender; and 0.0595-0.075 parts of a catalyst.

[0019] Optionally, the second small molecule chain extender is one or a mixture of ethanolamine, 1,4-butanediol or 1,6-hexanediol; and the catalyst is organic bismuth.

[0020] Optionally, the mass of the post-chain extender is 0.02-0.04% of the total mass of the component A and the component B;

[0021] The post-chain extender is a mixture of one or more of isophorone diamine, hydrazine hydrate, diethylene triamine, triethylene tetramine, diamino dicyclohexyl methane and trimethyl hexamethylene diamine;

[0022] The solvent is acetone or N-methylpyrrolidone.

[0023] The present invention also provides a method for preparing the aqueous polyurethane for the surfactant as described above, the preparation method comprising the following steps:

[0024] Step 1, weighing the raw materials of component A according to the ratio, mixing polyester polyol, silicone polyol, the first diisocyanate, the first small molecule chain extender and the hydrophilic chain extender, and adding a solvent to react to obtain a polyurethane prepolymer A;

[0025] Step 2, sequentially adding a solvent, a neutralizing agent and deionized water to the polyurethane prepolymer A for neutralization and dispersion to obtain a modified waterborne polyurethane dispersion A;

[0026] Step 3, weighing the raw materials of component B according to the ratio, mixing the polyether polyol, the silicone polyol, the second diisocyanate, the first small molecule chain extender and the hydrophilic chain extender, and adding a solvent to react to obtain a polyurethane prepolymer B;

[0027] Step 4, sequentially adding a solvent, a neutralizing agent and deionized water to the polyurethane prepolymer B for neutralization and dispersion to obtain a modified waterborne polyurethane dispersion B;

[0028] Step 5: Mix the modified waterborne polyurethane dispersion A and the modified waterborne polyurethane dispersion B, add a post-chain extender to carry out a post-chain extension reaction, and remove the solvent to obtain a waterborne polyurethane for surfactant.

[0029] Optionally, in step 1, the reaction temperature is 60-70°C;

[0030] In step 1, the reaction process is monitored by di-n-butylamine titration method. When it is detected that the NCOwt% in the reaction system reaches the theoretical value, the reaction is stopped to obtain A polyurethane prepolymer;

[0031] Step 2 is specifically as follows: when the system temperature of the A polyurethane prepolymer drops to 30-40°C, a solvent is added and stirred for 20-30 minutes, a neutralizer is added and stirred for 20-30 minutes, and then dispersed with deionized water at a rotation speed of 1000-1500 rpm, and stirring is continued for 20-30 minutes to obtain a modified waterborne A polyurethane dispersion.

[0032] Optionally, in step 3, the reaction temperature is 60-70°C;

[0033] In step 3, the reaction process is monitored by di-n-butylamine titration method. When it is detected that the NCOwt% in the reaction system reaches the theoretical value, the reaction is stopped to obtain B polyurethane prepolymer;

[0034] Step 4 is as follows: when the system temperature of the B polyurethane prepolymer drops to 30-40°C, add the solvent and stir for 20-30 minutes, add the neutralizer and stir for 20-30 minutes, then disperse with deionized water at a speed of 1000-1500 rpm, continue stirring for 20-30 minutes, and obtain a modified waterborne B polyurethane dispersion.

[0035] The present invention also provides an application of the aqueous polyurethane as a surface treatment agent as described above, wherein the aqueous polyurethane as a surface treatment agent is applied to the preparation of a special fog and special black synthetic leather surface treatment agent.

[0036] Beneficial effects:

[0037] The invention discloses a water-based polyurethane for a surfactant, comprising an A component, a B component, a post-chain extender and a solvent, wherein the A component and the B component have different types of polyols and different types of isocyanates, so that two polymers formed thereby have different softness and hardness, and the contents of the hydrophilic chain extender are different, so that the sizes of nanoparticles of the two polymers formed thereby are different. Finally, a method of post-chain extension is used to obtain a water-based polyurethane for a surfactant with comprehensive properties such as good anti-fouling effect and skin feel effect, thereby well solving the problem that the current water-based bulk matting resin has special fog and special black properties but is difficult to store stably. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0039] The present invention will be described in detail below in conjunction with embodiments. It should be noted that the embodiments and features in the embodiments of the present invention can be combined with each other without conflict.

[0040] In order to solve the problem that the current water-based bulk matte resin has special fog and black properties but is difficult to store stably, the present invention provides a water-based polyurethane for a surfactant, aiming to obtain a water-based polyurethane for a surfactant with comprehensive properties such as good anti-fouling effect and skin feel effect.

[0041] The aqueous polyurethane for surfactant of the present invention comprises component A, component B, a post-chain extender and a solvent, wherein, by weight, component A comprises: polyester polyol, 17.1-18.55 parts (such as 17.1 parts, 17.5 parts, 17.8 parts, 18 parts, 18.2 parts, 18.55 parts and the interval between any two end points); organosilicon polyol, 1-1.52 parts (such as 1 part, 1.1 parts, 1.2 parts, 1.3 parts, 1.4 parts, 1.52 parts and the interval between any two end points); a first diisocyanate, 8-9.3 parts (such as 8 parts, 8.2 parts, 8.5 parts, 8.8 parts, 9 parts, 9.3 parts and the interval between any two end points); a first small molecule chain extender, 0.1 7-0.35 parts (for example, 0.17 parts, 0.2 parts, 0.25 parts, 0.3 parts, 0.35 parts and the interval between any two end points); hydrophilic chain extender, 0.31-0.55 parts (for example, 0.31 parts, 0.35 parts, 0.4 parts, 0.45 parts, 0.5 parts, 0.55 parts and the interval between any two end points); neutralizer, 0.13-0.35 parts (for example, 0.13 parts, 0.15 parts, 0.2 parts, 0.25 parts, 0.3 parts, 0.35 parts and the interval between any two end points); deionized water, 69.5-70.5 parts (for example, 69.5 parts, 69.8 parts, 70 parts, 70.3 parts, 70.5 parts and the interval between any two end points).

[0042] In parts by mass, component B includes: polyether polyol, 17.1-20.55 parts (such as 17.1 parts, 17.5 parts, 17.8 parts, 18 parts, 18.2 parts, 18.55 parts, 19 parts, 19.5 parts, 20 parts, 20.55 parts and intervals between any two end points); organosilicon polyol, 1-1.52 parts (such as 1 part, 1.1 parts, 1.2 parts, 1.3 parts, 1.4 parts, 1.52 parts and intervals between any two end points); second diisocyanate, 6.05-9.3 parts (such as 6.05 parts, 6.5 parts, 7 parts, 7.5 parts, 8 parts, 8.2 parts, 8.5 parts, 8.8 parts, 9 parts, 9.3 parts and intervals between any two end points); first small molecule chain extender, 0.17-0. 35 parts (for example, 0.17 parts, 0.2 parts, 0.25 parts, 0.3 parts, 0.35 parts and the interval between any two endpoints); hydrophilic chain extender, 0.57-0.82 parts (for example, 0.57 parts, 0.6 parts, 0.65 parts, 0.7 parts, 0.75 parts, 0.8 parts, 0.82 parts and the interval between any two endpoints); neutralizer, 0.39-0.67 parts (for example, 0.39 parts, 0.4 parts, 0.45 parts, 0.5 parts, 0.55 parts, 0.6 parts, 0.65 parts, 0.67 parts and the interval between any two endpoints); deionized water, 69.5-70.5 parts (for example, 69.5 parts, 69.8 parts, 70 parts, 70.3 parts, 70.5 parts and the interval between any two endpoints).

[0043] It should be noted that the traditional matting WPU is a compound of polyurethane and matting agent. The tiny particles of the matting agent will migrate to the surface of the coating to produce the expected roughness when the coating is drying. Ultrafine particles have an absorption effect on light waves and also have a scattering effect, which significantly reduces its surface gloss, thereby achieving surface extinction. Self-matting WPU can achieve self-matting on the coating surface by controlling the particle size and distribution state of the emulsion. During the formation of the coating, its particles will deform, and some particles may fuse, but the signs of the existence of particles on the surface will not disappear. Relying on the characteristics of the resin itself, the different stress effects of the particles during the drying film make the surface film concave and convex, forming light scattering, low gloss, and obvious atomization. Therefore, the concave and convex surface state of the drying film caused by the regulation of the particle size of the nanoparticles and the regulation of the hardness of the nanoparticles has a great effect on stabilizing the matting emulsion.

[0044] In the system of the present invention, due to the different types of polyols and isocyanates in component A and component B, the two polymers formed are different in hardness and softness, and the content of the hydrophilic chain extender is different, so the sizes of the nanoparticles of the two polymers formed are different, that is, there are nanoparticles A with large particle size and relatively hardness, and there are nanoparticles B with smaller particle size and relatively softness. The two nanoparticles in the system are synthesized and dispersed separately, but not simply physically blended. After blending in a certain proportion, a post-chain extender is added at high speed for chain extension. According to the research of Jung-Hyun Kim et al., the remaining NCO on the polymer will exist inside and outside the nanoparticles, and may eventually form an AB-like structure, which will help the stability of the emulsion. By adjusting the structure of A and B and the ratio of component A and component B in the system, using the method of post-blend chain extension, a stable special fog and special black water-based surfactant can be finally obtained.

[0045] In an optional embodiment of the present invention, the polyester polyol is one or a mixture of polycarbonate diol and polycaprolactone diol, and the number average molecular weight of the polyester polyol is 1000-2000 g / mol (for example, 1000 g / mol, 1200 g / mol, 1400 g / mol, 1600 g / mol, 1800 g / mol, 2000 g / mol and any interval value between the two end points.

[0046] In an optional embodiment of the present invention, the polyether polyol is one or a mixture of polytetrahydrofuran diol and polyoxypropylene diol, and the number average molecular weight of the polyether polyol is 1000-2000 g / mol (for example, 1000 g / mol, 1200 g / mol, 1400 g / mol, 1600 g / mol, 1800 g / mol, 2000 g / mol and an interval value between any two end point values).

[0047] In an optional embodiment of the present invention, the organosilicon polyol is an organosilicon diol with a side chain, and the number average molecular weight of the organosilicon polyol is 1000-2000 g / mol (for example, 1000 g / mol, 1200 g / mol, 1400 g / mol, 1600 g / mol, 1800 g / mol, 2000 g / mol and interval values ​​between any two end points). It should be noted that the organosilicon polyol in component A and the organosilicon polyol in component B can both be organosilicon diols with side chains, and the two can be the same or different.

[0048] In an optional embodiment of the present invention, the first diisocyanate is 4,4'-dicyclohexylmethane diisocyanate.

[0049] In an optional embodiment of the present invention, the second diisocyanate is one of isophorone diisocyanate and hexamethylene diisocyanate, or a mixture of the two.

[0050] In an optional embodiment of the present invention, the first small molecule chain extender is one of trimethylolpropane and trimethylolethane, or a mixture of the two. It should be noted that the first small molecule chain extender in component A and the first small molecule chain extender in component B can both be one of trimethylolpropane and trimethylolethane, or a mixture of the two, and the two can be the same or different.

[0051] In an optional embodiment of the present invention, the hydrophilic chain extender is one of dimethylolpropionic acid and dimethylolbutyric acid, or a mixture of two of them; it should be noted that the hydrophilic chain extender in component A and the hydrophilic chain extender in component B can both be one of dimethylolpropionic acid and dimethylolbutyric acid, or a mixture of two of them, and the two can be the same or different.

[0052] In an optional embodiment of the present invention, the neutralizing agent is triethylamine or potassium hydroxide. It should be noted that the neutralizing agent in component A and the neutralizing agent in component B can both be triethylamine.

[0053] Furthermore, in parts by mass, the A component also includes: a second small molecule chain extender, 0.71-0.95 parts (such as 0.71 parts, 0.75 parts, 0.8 parts, 0.85 parts, 0.9 parts, 0.95 parts and interval values ​​between any two end points); a catalyst, 0.05-0.07 parts (such as 0.05 parts, 0.06 parts, 0.07 parts and interval values ​​between any two end points).

[0054] In parts by mass, component B also includes: a second small molecule chain extender, 0.71-0.85 parts (such as 0.71 parts, 0.75 parts, 0.8 parts, 0.85 parts and intervals between any two end points); a catalyst, 0.0595-0.075 parts (such as 0.0595 parts, 0.06 parts, 0.065 parts, 0.07 parts, 0.075 parts and intervals between any two end points).

[0055] In an optional embodiment of the present invention, the second small molecule chain extender is one or a mixture of ethanolamine, 1,4-butanediol or 1,6-hexanediol; it should be noted that the second small molecule chain extender in component A and the second small molecule chain extender in component B can both be one or a mixture of ethanolamine, 1,4-butanediol or 1,6-hexanediol, and the two can be the same or different.

[0056] In an optional embodiment of the present invention, the catalyst is organic bismuth. It should be noted that the catalyst in component A and the catalyst in component B can both be organic bismuth.

[0057] In an optional embodiment of the present invention, the ratio of the mass of the post-chain extender to the total mass of component A and component B is 0.02-0.04% (such as 0.02%, 0.03%, 0.04% and any interval between the two end points).

[0058] In an optional embodiment of the present invention, the post-chain extender is a mixture of one or more of isophorone diamine, hydrazine hydrate, diethylene triamine, triethylene tetramine, diaminodicyclohexyl methane and trimethyl hexamethylene diamine;

[0059] In an optional embodiment of the present invention, the solvent is acetone or N-methylpyrrolidone.

[0060] The present invention also provides a method for preparing the aqueous polyurethane for surface treatment as described above, the preparation method comprising the following steps:

[0061] Step 1, weighing the raw materials of component A according to the ratio, mixing polyester polyol, silicone polyol, the first diisocyanate, the first small molecule chain extender and the hydrophilic chain extender, and adding a solvent to react to obtain A polyurethane prepolymer.

[0062] In a specific embodiment of the present invention, step 1 is specifically as follows: vacuum dehydrated polyester polyol, organosilicon polyol, first diisocyanate, first small molecule chain extender and hydrophilic chain extender are sequentially added to a reactor equipped with a reflux tube, a stirring device and a thermometer according to a proportion, and a solvent is added, the temperature of the reaction device is raised to 60-70°C (such as 60°C, 62°C, 64°C, 66°C, 68°C, 70°C and the interval between any two end points), the reaction process is monitored by di-n-butylamine titration, and when it is detected that the NCOwt% in the reaction system reaches the theoretical value, the reaction is stopped to obtain A polyurethane prepolymer, and A polyurethane prepolymer is in the form of an emulsion. It should be noted that the theoretical value of NCO% is determined based on the above reactants, which is 3.13 here.

[0063] Furthermore, a second small molecule chain extender and a catalyst are added into the reactor in proportion.

[0064] Step 2: Add solvent, neutralizing agent and deionized water to polyurethane prepolymer A in sequence to neutralize and disperse the prepolymer to obtain modified waterborne polyurethane dispersion A.

[0065] In a specific embodiment of the present invention, step 2 is specifically as follows: lowering the system temperature of the polyurethane prepolymer emulsion A to 30-40°C (e.g., 30°C, 32°C, 34°C, 36°C, 38°C, 40°C and any interval between the two end points), adding a solvent to reduce its viscosity, stirring for 20-30min (e.g., 20min, 22min, 24min, 26min, 28min, 30min and any interval between the two end points), adding a neutralizer, stirring for 20-30min (e.g., 20min, 22min, 24min, 26min, 28min, 30min and any interval between the two end points), and stirring for 20-30min (e.g., 20min, 22min, 24min, 26min, 28min, 30min and any interval between the two end points). 0min and the interval between any two end point values), then dispersed with deionized water at a rotation speed of 1000-1500rpm (such as 1000rpm, 1100rpm, 1200rpm, 1300rpm, 1400rpm, 1500rpm and the interval between any two end point values), and continued stirring for 20-30min (such as 20min, 22min, 24min, 26min, 28min, 30min and the interval between any two end point values) to obtain a modified waterborne A polyurethane dispersion, which is in the form of an emulsion.

[0066] It should be noted that the solvent can be selected from acetone or N-methylpyrrolidone, wherein the mass ratio of the amount of solvent added in step 1 to the total amount of other substances in the reaction system is (15-25): (75-85), such as the mass ratio of 15:75, 15:80, 15:85, 20:75, 20:80, 20:85, 25:75, 25:80, 25:85 and the interval between any two endpoints. The mass ratio of the sum of the amount of solvent added in step 1 and the amount of solvent added in step 2 to the total amount of other substances in the reaction system is (55-65): (35-45), such as the mass ratio of 55:35, 55:40, 55:45, 60:35, 60:40, 60:45, 65:35, 65:40, 65:45 and the interval between any two endpoints.

[0067] Step 3, weighing the raw materials of component B according to the ratio, mixing the polyether polyol, the silicone polyol, the second diisocyanate, the first small molecule chain extender and the hydrophilic chain extender, and adding a solvent to react to obtain a B polyurethane prepolymer.

[0068] In a specific embodiment of the present invention, the vacuum dehydrated polyether polyol, silicone polyol, second diisocyanate, first small molecule chain extender and hydrophilic chain extender are sequentially added to a reactor equipped with a reflux tube, a stirring device and a thermometer according to a proportion, and a solvent is added, and the temperature of the reaction device is raised to 60-70°C (for example, 60°C, 62°C, 64°C, 66°C, 68°C, 70°C and the interval between any two end points), and the reaction process is monitored by di-n-butylamine titration. When it is detected that the NCOwt% in the reaction system reaches the theoretical value, the reaction is stopped to obtain B polyurethane prepolymer, and B polyurethane prepolymer is in the form of an emulsion. It should be noted that the theoretical value of NCOwt% is determined based on the above reactants, which is 3.29 here.

[0069] Furthermore, a second small molecule chain extender and a catalyst are added into the reactor in proportion.

[0070] Step 4: Add solvent, neutralizing agent and deionized water to the B polyurethane prepolymer in sequence to neutralize and disperse the prepolymer to obtain a modified waterborne B polyurethane dispersion.

[0071] In a specific embodiment of the present invention, step 4 is specifically as follows: lowering the system temperature of the polyurethane prepolymer emulsion B to 30-40°C (e.g., 30°C, 32°C, 34°C, 36°C, 38°C, 40°C and any interval between the two end points), adding a solvent to reduce its viscosity, stirring for 20-30min (e.g., 20min, 22min, 24min, 26min, 28min, 30min and any interval between the two end points), adding a neutralizer, stirring for 20-30min (e.g., 20min, 22min, 24min, 26min, 28min, 30min and any interval between the two end points). 0min and the interval between any two end point values), then dispersed with deionized water at a rotation speed of 1000-1500rpm (such as 1000rpm, 1100rpm, 1200rpm, 1300rpm, 1400rpm, 1500rpm and the interval between any two end point values), and continued stirring for 20-30min (such as 20min, 22min, 24min, 26min, 28min, 30min and the interval between any two end point values) to obtain a modified waterborne B polyurethane dispersion, which is in the form of an emulsion.

[0072] It should be noted that the solvent can be selected from acetone or N-methylpyrrolidone, wherein the mass ratio of the amount of solvent added in step 3 to the total amount of other substances in the reaction system is (15-25): (75-85), such as the mass ratio of 15:75, 15:80, 15:85, 20:75, 20:80, 20:85, 25:75, 25:80, 25:85 and the interval between any two endpoints. The mass ratio of the sum of the amount of solvent added in step 3 and the amount of solvent added in step 4 to the total amount of other substances in the reaction system is (55-65): (35-45). For example, the mass ratio is 55:35, 55:40, 55:45, 60:35, 60:40, 60:45, 65:35, 65:40, 65:45 and the interval between any two endpoints.

[0073] Step 5: Mix the modified waterborne polyurethane dispersion A and the modified waterborne polyurethane dispersion B, add a post-chain extender to carry out a post-chain extension reaction, and remove the solvent to obtain a waterborne polyurethane for surfactant.

[0074] In a specific embodiment of the present invention, step five is specifically as follows: adding the modified waterborne polyurethane dispersion A and the modified waterborne polyurethane dispersion B into a reactor in a certain ratio, stirring for 5-10 min (e.g., 5 min, 6 min, 7 min, 8 min, 9 min, 10 min and any interval between the two end points) to fully mix them, adding a post-chain extender for a post-chain extension reaction, stirring for 5-10 min (e.g., 5 min, 6 min, 7 min, 8 min, 9 min, 10 min and any interval between the two end points), after the stirring is completed, removing the solvent acetone under reduced pressure distillation at 40-55° C. (e.g., 40° C., 42° C., 45° C., 50° C., 52° C., 55° C. and any interval between the two end points), and obtaining a water-based polyurethane for the surfactant.

[0075] The present invention also provides an application of the aqueous polyurethane as a surface treatment agent as described above, wherein the aqueous polyurethane as a surface treatment agent is applied to the preparation of a surface treatment agent for special fog and special black synthetic leather, which effectively solves the problem that the aqueous bulk matte resin has special fog and special black properties but is difficult to store stably, and at the same time enables the surface treatment agent to have comprehensive properties such as good anti-fouling effect and skin feel effect.

[0076] The aqueous polyurethane for surface treatment of the present invention and its preparation method are described in detail below through specific examples.

[0077] Example 1

[0078] This embodiment provides a method for preparing aqueous polyurethane for a surfactant, which specifically comprises the following steps:

[0079] (1) Synthesis of modified waterborne A polyurethane dispersion

[0080] 17.1 parts of vacuum dehydrated polycarbonate diol, 1.52 parts of silicone diol, 9.3 parts of 4,4'-dicyclohexylmethane diisocyanate, 0.18 parts of trimethylolpropane, 0.83 parts of 1,4-butanediol, 0.31 parts of hydrophilic chain extender dimethylolpropionic acid, 0.06 parts of organic bismuth catalyst, and 6.42 parts of acetone a were sequentially added into a reactor equipped with a reflux tube, a stirring device and a thermometer, the temperature of the reaction device was raised to 60°C, and the reaction process was monitored by di-n-butylamine titration until NCO% reached a theoretical value of 3.13; after reaching the theoretical NCO value, the system temperature was lowered to 30, 33.97 parts of acetone b were added to reduce the viscosity, stirred for 20 minutes, and 0.23 parts of triethylamine were added and stirred for 20 minutes; the neutralized prepolymer was dispersed with deionized water under the condition of high-speed stirring at 1000 rpm, and stirring was maintained for 20 minutes to obtain a modified waterborne A polyurethane dispersion. Among them, acetone a: the sum of other raw materials in the system = 20:80, (acetone a + acetone b): the sum of other raw materials in the system = 60:40.

[0081] (2) Synthesis of modified waterborne B polyurethane dispersion

[0082] 17.93 parts of vacuum dehydrated polytetrahydrofuran diol, 1.42 parts of silicone diol, 8.22 parts of isophorone diisocyanate, 0.17 parts of trimethylolpropane, 0.71 parts of 1,4-butanediol, 0.57 parts of hydrophilic chain extender dimethylolpropionic acid, 0.06 parts of organic bismuth catalyst, and 6.37 parts of acetone c were sequentially added into a reactor equipped with a reflux tube, a stirring device and a thermometer, the temperature of the reaction device was raised to 60°C, and the reaction process was monitored by di-n-butylamine titration until NCO% reached a theoretical value of 3.29; after reaching the theoretical NCO value, the system temperature was lowered to 30°C, 33.72 parts of acetone d were added to reduce the viscosity, stirred for 20 minutes, and 0.46 parts of triethylamine were added and stirred for 20 minutes; the neutralized prepolymer was dispersed with deionized water under the condition of high-speed stirring at 1000 rpm, and stirring was maintained for 20 minutes to obtain a modified waterborne B polyurethane dispersion. Among them, acetone c: the sum of other raw materials in the system = 20:80, (acetone c + acetone d): the sum of other raw materials in the system = 60:40.

[0083] (3) Synthesis of water-based polyurethane for surface treatment

[0084] Weigh 30 parts of the modified waterborne polyurethane dispersion emulsion A in the previous step, and weigh 70 parts of the modified waterborne polyurethane dispersion emulsion B, add them into the reactor and stir for 5 minutes, then add 0.38 parts of triethylenetetramine for post-chain extension, and stir for 10 minutes. After stirring, remove acetone by vacuum distillation at 40°C to obtain a waterborne polyurethane for surfactant.

[0085] Example 2

[0086] The difference between this embodiment and embodiment 1 is that in the synthesis of aqueous polyurethane for surfactant in step (3), 50 parts of modified aqueous polyurethane dispersion emulsion A and 50 parts of modified aqueous polyurethane dispersion emulsion B are weighed, and the other operations are the same as those in embodiment 1.

[0087] Example 3

[0088] The difference between this embodiment and embodiment 1 is that in the synthesis of aqueous polyurethane for surfactant in step (3), 70 parts of modified aqueous polyurethane dispersion emulsion A and 30 parts of modified aqueous polyurethane dispersion emulsion B are weighed, and other operations are the same as those in embodiment 1.

[0089] Example 4

[0090] This embodiment provides a method for preparing aqueous polyurethane for a surfactant, which specifically comprises the following steps:

[0091] (1) Synthesis of modified waterborne A polyurethane dispersion

[0092] 17.6 parts of vacuum dehydrated polycarbonate diol, 1.32 parts of silicone diol, 8.8 parts of 4,4'-dicyclohexylmethane diisocyanate, 0.25 parts of trimethylolpropane, 0.82 parts of 1,4-butanediol, 0.42 parts of hydrophilic chain extender dimethylolpropionic acid, 0.05 parts of organic bismuth catalyst and part of acetone a are sequentially added into a reactor equipped with a reflux tube, a stirring device and a thermometer, the temperature of the reaction device is raised to 65°C, and the reaction process is monitored by di-n-butylamine titration method until NCOwt% reaches a theoretical value of 3.13; after reaching the theoretical value of NCO, the system temperature is lowered to 35°C, acetone b is added to reduce the viscosity, stirred for 25 minutes, 0.13 parts of triethylamine are added, and stirred for 25 minutes; the neutralized prepolymer is dispersed with deionized water under the condition of high-speed stirring at 1200 rpm, and stirring is maintained for 25 minutes to obtain a modified waterborne polyurethane dispersion. Among them, acetone a: the sum of other raw materials in the system = 20:80, (acetone a + acetone b): the sum of other raw materials in the system = 60:40.

[0093] (2) Synthesis of modified waterborne B polyurethane dispersion

[0094] 17.6 parts of vacuum dehydrated polytetrahydrofuran diol, 1.32 parts of silicone diol, 6.05 parts of isophorone diisocyanate, 0.25 parts of trimethylolpropane, 0.78 parts of 1,4-butanediol, 0.72 parts of hydrophilic chain extender dimethylolpropionic acid, 0.0595 parts of organic bismuth catalyst, and c parts of acetone were sequentially added into a reactor equipped with a reflux tube, a stirring device and a thermometer, the temperature of the reaction device was raised to 65° C., and the reaction process was monitored by di-n-butylamine titration method until NCOwt% reached a theoretical value of 3.29; after reaching the theoretical NCO value, the system temperature was lowered to 35° C., acetone d was added to reduce the viscosity, stirred for 25 minutes, and 0.39 parts of triethylamine were added and stirred for 25 minutes; the neutralized prepolymer was dispersed with deionized water under the condition of high-speed stirring at 1200 rpm, and stirring was maintained for 25 minutes to obtain a modified waterborne B polyurethane dispersion. Among them, acetone c: the sum of other raw materials in the system = 20:80, (acetone c + acetone d): the sum of other raw materials in the system = 60:40.

[0095] (3) Synthesis of water-based polyurethane for surface treatment

[0096] Weigh 45 parts of the modified waterborne polyurethane dispersion emulsion A in the previous step, and weigh 55 parts of the modified waterborne polyurethane dispersion emulsion B, add them into the reactor and stir for 5 minutes, then add 0.02 parts of triethylenetetramine for post-chain extension, and stir for 10 minutes. After stirring, remove acetone by vacuum distillation at 45°C to obtain a waterborne polyurethane for surfactant.

[0097] Example 5

[0098] This embodiment provides a method for preparing aqueous polyurethane for a surfactant, which specifically comprises the following steps:

[0099] (1) Synthesis of modified waterborne A polyurethane dispersion

[0100] 18.55 parts of vacuum dehydrated polycarbonate diol, 1 part of silicone diol, 8 parts of 4,4'-dicyclohexylmethane diisocyanate, 0.35 parts of trimethylolpropane, 0.95 parts of 1,4-butanediol, 0.55 parts of hydrophilic chain extender dimethylolpropionic acid, 0.07 parts of organic bismuth catalyst, and part of N-methylpyrrolidone a are sequentially added into a reactor equipped with a reflux tube, a stirring device and a thermometer, the temperature of the reaction device is raised to 70°C, and the reaction process is monitored by di-n-butylamine titration method until NCOwt% reaches a theoretical value of 3.13; after reaching the theoretical value of NCOwt%, the system temperature is lowered to 40°C, N-methylpyrrolidone b is added to reduce the viscosity, stirred for 30 minutes, and 0.35 parts of potassium hydroxide are added and stirred for 30 minutes; the neutralized prepolymer is dispersed with deionized water under the condition of high-speed stirring at 1500rpm, and stirring is maintained for 30 minutes to obtain a modified waterborne polyurethane dispersion. Among them, N-methylpyrrolidone a: the sum of other raw materials in the system = 20:80, (N-methylpyrrolidone a + N-methylpyrrolidone b): the sum of other raw materials in the system = 60:40.

[0101] (2) Synthesis of modified waterborne B polyurethane dispersion

[0102] 20.55 parts of vacuum dehydrated polytetrahydrofuran diol, 1 part of organosilicon diol, 9.3 parts of isophorone diisocyanate, 0.35 parts of trimethylolpropane, 0.85 parts of 1,4-butanediol, 0.82 parts of hydrophilic chain extender dimethylolpropionic acid, 0.075 parts of organic bismuth catalyst and c parts of N-methylpyrrolidone are sequentially added into a reactor equipped with a reflux tube, a stirring device and a thermometer, the temperature of the reaction device is raised to 70°C, and the reaction process is monitored by di-n-butylamine titration method until NCO% reaches a theoretical value of 3.29; after reaching the theoretical value of NCOwt%, the system temperature is lowered to 40°C, N-methylpyrrolidone d is added to reduce the viscosity, stirred for 30 minutes, 0.67 parts of potassium hydroxide are added, and stirred for 30 minutes; the neutralized prepolymer is dispersed with deionized water under the condition of high-speed stirring at 1500 rpm, and stirring is maintained for 30 minutes to obtain a modified waterborne polyurethane dispersion. Among them, N-methylpyrrolidone c: the sum of other raw materials in the system = 20:80, (N-methylpyrrolidone c + N-methylpyrrolidone d): the sum of other raw materials in the system = 60:40.

[0103] (3) Synthesis of water-based polyurethane for surface treatment

[0104] Weigh 75 parts of the modified waterborne polyurethane dispersion emulsion A in the previous step, and weigh 25 parts of the modified waterborne polyurethane dispersion emulsion B, add them into the reactor and stir for 5 minutes, then add 0.04 parts of triethylenetetramine for post-chain extension, and stir for 10 minutes. After stirring, remove acetone by vacuum distillation at 55° C. to obtain a waterborne polyurethane for surfactant.

[0105] Example 6

[0106] The difference between this embodiment and embodiment 2 is that in step (1), polycarbonate diol is replaced by polycaprolactone diol, and the other operations are the same as those in embodiment 2.

[0107] Example 7

[0108] The difference between this embodiment and embodiment 2 is that, in step (1), polytetrahydrofuran diol is replaced by polyoxypropylene diol, and other operations are the same as in embodiment 2.

[0109] Comparative Example 1

[0110] The difference between this comparative example and Example 1 is that the synthesis operation of the modified waterborne B polyurethane dispersion in step (2) is removed, and in step (3), the amount of triethylenetetramine added to 100 parts of the modified waterborne A polyurethane dispersion is 0.033 parts, and the other operations are the same as in Example 1.

[0111] Comparative Example 2

[0112] The difference between this comparative example and Example 1 is that the synthesis operation of the modified waterborne A polyurethane dispersion in step (1) is removed, and in step (3), the amount of triethylenetetramine added to 100 parts of the modified waterborne B polyurethane dispersion is 0.033 parts, and the other operations are the same as in Example 1.

[0113] Comparative Example 3

[0114] The difference between this comparative example and Example 1 is that, in the step (1) of synthesizing the modified waterborne polyurethane dispersion A, 0.52 parts of triethylenetetramine are added for post-chain extension; in the step (2) of synthesizing the modified waterborne polyurethane dispersion B, 0.53 parts of triethylenetetramine are added for post-chain extension; and in the step (3), the above are directly mixed to obtain a waterborne polyurethane for surfactant.

[0115] The aqueous polyurethane used in the surface treatment agents obtained in the above-mentioned embodiments and comparative examples was tested for particle size. The test results are shown in Table 1.

[0116] The surface treatment agent obtained in the above-mentioned embodiments and comparative examples was prepared by adding a nitrogen pyridine curing agent, a thickener and a leveling agent to the aqueous polyurethane and then applied to the synthetic leather, and baked at 120° C. for 3 minutes. The glossiness was tested using a gloss meter. The test results are shown in Table 1.

[0117] Table 1 Performance parameters of various embodiments and comparative examples

[0118]

[0119]

[0120] As can be seen from Table 1, the aqueous polyurethane emulsions of the surface treatment agents of Examples 1-7 are mixed with different particle sizes and polymers of different hardness, and polyamines are used for chain extension after mixing. After the mixed reaction, the emulsions have good extinction properties. At the same time, as the large and hard emulsion components in the emulsions of Examples 1-3 increase, the extinction properties are enhanced, but the storage stability of the emulsions will deteriorate. Compared with Example 2, Examples 4 and 5 are different only in that the polyols used in components A and B are different, but the structural properties are similar. The comprehensive performance of Example 2 is the best.

[0121] Comparative Example 1 is compared with Example 2, and the only difference is that in Comparative Example 1, only the large and hard particles of component A are present.

[0122] Comparative Example 2 is compared with Example 2, and the only difference is that Comparative Example 2 contains only small and soft particles of component B.

[0123] Comparative Example 3 is compared with Example 2, and the only difference is that in Comparative Example 2, hard and large particles and small and soft particles are directly mixed, and polyamine chain extension is performed separately before mixing.

[0124] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A water-based polyurethane for a surfactant, characterized in that: The aqueous polyurethane for treating agent comprises component A, component B, a post-chain extender and a solvent, wherein: In parts by mass, the component A comprises: polyester polyol, 17.1-18.55 parts; silicone polyol, 1-1.52 parts; first diisocyanate, 8-9.3 parts; first small molecule chain extender, 0.17-0.35 parts; hydrophilic chain extender, 0.31-0.55 parts; neutralizer, 0.13-0.35 parts; deionized water, 69.5-70.5 parts; In parts by mass, the B component includes: polyether polyol, 17.1-20.55 parts; silicone polyol, 1-1.52 parts; second diisocyanate, 6.05-9.3 parts; first small molecule chain extender, 0.17-0.35 parts; hydrophilic chain extender, 0.57-0.82 parts; neutralizer, 0.39-0.67 parts; deionized water, 69.5-70.5 parts; The polyester polyol is one of polycarbonate diol and polycaprolactone diol or a mixture of the two, and the number average molecular weight of the polyester polyol is 1000-2000 g / mol; The polyether polyol is one or a mixture of polytetrahydrofuran diol and polyoxypropylene diol, and the number average molecular weight of the polyether polyol is 1000-2000 g / mol; The organosilicon polyol is an organosilicon diol with a side chain, and the number average molecular weight of the organosilicon polyol is 1000-2000 g / mol; The first diisocyanate is 4,4'-dicyclohexylmethane diisocyanate; The second diisocyanate is one or a mixture of isophorone diisocyanate and hexamethylene diisocyanate; The first small molecule chain extender is one of trimethylolpropane and trimethylolethane or a mixture of the two; The hydrophilic chain extender is one of dimethylol propionic acid and dimethylol butyric acid or a mixture of the two; The neutralizing agent is triethylamine or potassium hydroxide; In parts by mass, the component A further comprises: a second small molecule chain extender, 0.71-0.95 parts; a catalyst, 0.05-0.07 parts; In parts by mass, the B component further comprises: a second small molecule chain extender, 0.71-0.85 parts; a catalyst, 0.0595-0.075 parts; The second small molecule chain extender is one or a mixture of ethanolamine, 1,4-butanediol or 1,6-hexanediol; The catalyst is organic bismuth; The mass ratio of the post-chain extender to the total mass of the component A and the component B is 0.02-0.04%; The post-chain extender is a mixture of one or more of isophorone diamine, hydrazine hydrate, diethylene triamine, triethylene tetramine, diamino dicyclohexyl methane and trimethyl hexamethylene diamine; The solvent is acetone or N-methylpyrrolidone.

2. A method for preparing the aqueous polyurethane for surface treatment as claimed in claim 1, characterized in that: The preparation method comprises the following steps: Step 1, weighing the raw materials of component A according to the ratio, mixing polyester polyol, silicone polyol, the first diisocyanate, the first small molecule chain extender and the hydrophilic chain extender, and adding a solvent to react to obtain a polyurethane prepolymer A; Step 2, sequentially adding a solvent, a neutralizing agent and deionized water to the polyurethane prepolymer A for neutralization and dispersion to obtain a modified waterborne polyurethane dispersion A; Step 3, weighing the raw materials of component B according to the ratio, mixing the polyether polyol, the silicone polyol, the second diisocyanate, the first small molecule chain extender and the hydrophilic chain extender, and adding a solvent to react to obtain a polyurethane prepolymer B; Step 4, sequentially adding a solvent, a neutralizing agent and deionized water to the polyurethane prepolymer B for neutralization and dispersion to obtain a modified waterborne polyurethane dispersion B; Step 5: Mix the modified waterborne polyurethane dispersion A and the modified waterborne polyurethane dispersion B, add a post-chain extender to carry out a post-chain extension reaction, and remove the solvent to obtain a waterborne polyurethane for surfactant.

3. The method for preparing the aqueous polyurethane for surface treatment as claimed in claim 2, characterized in that: In step 1, the reaction temperature is 60-70°C; In step 1, the reaction process is monitored by di-n-butylamine titration method. When it is detected that the NCOwt% in the reaction system reaches the theoretical value, the reaction is stopped to obtain A polyurethane prepolymer; Step 2 is specifically as follows: when the system temperature of the A polyurethane prepolymer drops to 30-40°C, a solvent is added and stirred for 20-30 minutes, a neutralizer is added and stirred for 20-30 minutes, and then dispersed with deionized water at a rotation speed of 1000-1500 rpm, and stirring is continued for 20-30 minutes to obtain a modified waterborne A polyurethane dispersion.

4. The method for preparing the aqueous polyurethane for surface treatment as claimed in claim 2, characterized in that: In step 3, the reaction temperature is 60-70°C; In step 3, the reaction process is monitored by di-n-butylamine titration method. When it is detected that the NCOwt% in the reaction system reaches the theoretical value, the reaction is stopped to obtain B polyurethane prepolymer; Step 4 is as follows: when the system temperature of the B polyurethane prepolymer drops to 30-40°C, add the solvent and stir for 20-30 minutes, add the neutralizer and stir for 20-30 minutes, then disperse with deionized water at a speed of 1000-1500 rpm, continue stirring for 20-30 minutes, and obtain a modified waterborne B polyurethane dispersion.

5. An application of the aqueous polyurethane as a surface treatment agent as claimed in claim 1, characterized in that: The aqueous polyurethane used in the surface treatment agent is applied to the preparation of the surface treatment agent for special fog and special black synthetic leather.

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