An acid-resistant aqueous polyurethane sizing agent, its preparation method and application

Abstract

The present invention provides an acid-resistant aqueous polyurethane sizing agent, a preparation method thereof and an application. The raw materials for preparing the acid-resistant aqueous polyurethane sizing agent include a combination of polymer diol, diisocyanate, hydrophilic monomer, small molecule chain extender, catalyst and water, and the hydrophilic monomer includes a combination of sodium 3-hydroxypropanesulfonate and ethoxy-terminated polyethylene glycol. By selecting the combination of sodium 3-hydroxypropanesulfonate and ethoxy-terminated polyethylene glycol as the hydrophilic monomer, the finally obtained polyurethane sizing agent can have excellent hydrophilicity and excellent acid resistance at the same time, and also has high water solubility under acidic conditions, and is suitable for use as a textile sizing agent.

Description

Technical Field

[0001] The present invention belongs to the technical field of polyurethanes, and particularly relates to an acid-resistant aqueous polyurethane sizing agent and its preparation method and application. Background Art

[0002] Aqueous polyurethane (WPU) has the advantages of low odor, environmental protection, and simple preparation, and is thus widely used in fields such as coatings, adhesives, inks, and leather making. Among them, self-emulsifying aqueous polyurethane has good water solubility, excellent stability, initial adhesion strength, and bonding strength, and can be studied as a textile sizing agent.

[0003] The molecular chain of self-emulsifying aqueous polyurethane contains hydrophilic groups, and the hydrophilicity of aqueous polyurethane can be increased by adjusting the content of hydrophilic groups. When used as a textile sizing agent, the hydrophilic property of aqueous polyurethane should be good to facilitate the desizing of subsequent textile products.

[0004] Currently, the commonly used technical means to improve the hydrophilicity of aqueous polyurethane is to use dimethylolpropionic acid as a hydrophilic chain extender. CN107841875A discloses an aqueous polyurethane sizing agent, which comprises the following components in parts by mass: 12-20 parts of aqueous polyurethane, 30-40 parts of starch, and 40-60 parts of water. The aqueous polyurethane is a mixture composed of toluene diisocyanate, polypropylene glycol, and dimethylolpropionic acid, and the mass ratio of toluene diisocyanate, polypropylene glycol, and dimethylolpropionic acid is 10:3:3. This aqueous polyurethane sizing agent is easy to desize, has a fast biodegradation rate, and no environmental pollution.

[0005] However, since dimethylolpropionic acid is an organic carboxylic acid, its water solubility decreases under acidic conditions. Therefore, the acid-resistant aqueous polyurethane sizing agent prepared by using the above dimethylolpropionic acid as a hydrophilic chain extender has poor acid resistance, which limits its application in textile sizing agents.

[0006] Therefore, it is expected to develop an aqueous polyurethane sizing agent with excellent acid resistance to solve the above technical problems. Summary of the Invention

[0007] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide an acid-resistant aqueous polyurethane sizing agent and its preparation method and application. The raw materials for preparing the acid-resistant aqueous polyurethane sizing agent include a combination of polymer diol, diisocyanate, hydrophilic monomer, small molecule chain extender, catalyst, and water. By defining that the hydrophilic monomer includes a combination of sodium 3-sulfolactate and ethoxy-terminated polyethylene glycol, on the one hand, the finally obtained polyurethane sizing agent has excellent hydrophilicity, and at the same time effectively improves its acid resistance, so that the obtained aqueous polyurethane sizing agent also has high water solubility under acidic conditions and is suitable for use as a textile sizing agent.

[0008] To achieve this purpose, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides an acid-resistant aqueous polyurethane sizing agent. The raw materials for preparing the acid-resistant aqueous polyurethane sizing agent include a combination of polymer diol, diisocyanate, hydrophilic monomer, small molecule chain extender, catalyst, and water;

[0010] The hydrophilic monomer includes a combination of sodium dihydroxypropyl sulfonate and ethoxy-terminated polyethylene glycol.

[0011] The raw materials for preparing the acid-resistant aqueous polyurethane sizing agent provided by the present invention include a combination of polymer diol, diisocyanate, hydrophilic monomer, small molecule chain extender, catalyst, and water, and the hydrophilic monomer includes a combination of sodium dihydroxypropyl sulfonate and ethoxy-terminated polyethylene glycol; by selecting sodium dihydroxypropyl sulfonate and ethoxy-terminated polyethylene glycol as the hydrophilic monomer, the acid resistance of sodium dihydroxypropyl sulfonate is stronger than that of carboxymethyl salt, and ethoxy-terminated polyethylene glycol is a non-ionic hydrophilic monomer, and non-ionic has good acid and alkali resistance. The two cooperate coordinately to make the finally obtained polyurethane sizing agent have excellent hydrophilicity and acid resistance, so that it also has high water solubility under acidic conditions and is suitable for use as a textile sizing agent.

[0012] Preferably, the total molar ratio of the polymer diol, hydrophilic monomer, and small molecule chain extender to the diisocyanate is 1:(1-1.5), such as 1:1.05, 1:1.1, 1:1.15, 1:1.2, 1:1.25, 1:1.3, 1:1.35, 1:1.4, or 1:1.45, etc.

[0013] Preferably, the polymer diol is selected from polypropylene glycol.

[0014] Preferably, the diisocyanate is selected from toluene diisocyanate (TDI).

[0015] Preferably, the small molecule chain extender includes small molecule diol and / or small molecule diamine.

[0016] Preferably, the small molecule diol is selected from 1,4-butanediol.

[0017] Preferably, based on the total molar amount of the polymer diol, hydrophilic monomer, and small molecule chain extender being 100 mol%, the addition amount of the polymer diol is 30-40 mol%, such as 31 mol%, 32 mol%, 33 mol%, 34 mol%, 35 mol%, 36 mol%, 37 mol%, 38 mol%, or 39 mol%, etc.

[0018] Preferably, based on the total molar amount of the polymer diol, hydrophilic monomer and small molecule chain extender being 100 mol%, the addition amount of the hydrophilic monomer is 30 to 40 mol%, such as 31 mol%, 32 mol%, 33 mol%, 34 mol%, 35 mol%, 36 mol%, 37 mol%, 38 mol% or 39 mol%, etc.

[0019] Preferably, based on the total molar amount of the polymer diol, hydrophilic monomer and small molecule chain extender being 100 mol%, the addition amount of the small molecule chain extender is 30 to 40 mol%, such as 31 mol%, 32 mol%, 33 mol%, 34 mol%, 35 mol%, 36 mol%, 37 mol%, 38 mol% or 39 mol%, etc.

[0020] Preferably, the mass ratio of sodium 3-hydroxypropanesulfonate to ethoxy-terminated polyethylene glycol is (5 to 20):1, such as 7:1, 9:1, 11:1, 13:1, 15:1, 17:1 or 19:1, etc.

[0021] As a preferred technical solution of the present invention, defining the mass ratio of sodium 3-hydroxypropanesulfonate to ethoxy-terminated polyethylene glycol as (5 to 20):1 can make the obtained aqueous polyurethane slurry stable, with a moderate viscosity, showing light yellow semi-transparency, and having excellent acid resistance. If the addition ratio of ethoxy-terminated polyethylene glycol is too high, the viscosity of the obtained aqueous polyurethane slurry will be too large, and if the addition ratio of ethoxy-terminated polyethylene glycol is too low, the obtained aqueous polyurethane slurry will show milky white and be prone to layering.

[0022] Preferably, based on the total mass of the raw materials for preparing the acid-resistant aqueous polyurethane slurry being 100%, the addition amount of the catalyst is 0.02 to 0.1%, such as 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08% or 0.09%, etc.

[0023] As a preferred technical solution of the present invention, limiting the addition amount of the catalyst to 0.02 to 0.1% helps the reaction to proceed smoothly and can ensure an appropriate reaction time. If the addition amount of the catalyst is too small, the reaction time will be too long, and if the addition amount of the catalyst is too large, the reaction will be too fast, making it difficult to control the subsequent chain extension process and resulting in a gel phenomenon.

[0024] Preferably, the catalyst is selected from any one or a combination of at least two of dibutyltin dilaurate, stannous octoate or bismuth neodecanoate.

[0025] Preferably, based on the total mass of the raw materials for preparing the acid-resistant aqueous polyurethane slurry being 100%, the addition amount of water is 60-70%, such as 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68% or 69%, etc.

[0026] Preferably, the raw materials for preparing the acid-resistant aqueous polyurethane slurry further include a solvent;

[0027] Preferably, the solvent includes water.

[0028] In a second aspect, the present invention provides a method for preparing the acid-resistant aqueous polyurethane slurry as described in the first aspect, and the preparation method includes the following steps:

[0029] (1) React polymer diol, diisocyanate and a catalyst to obtain a prepolymer;

[0030] (2) React the prepolymer obtained in step (1) with a hydrophilic monomer, add a small molecule chain extender and optionally a solvent for reaction, then add water for dispersion, and remove the optionally solvent to obtain the acid-resistant aqueous polyurethane slurry.

[0031] Preferably, the temperature of the reaction in step (1) is 60-80°C, such as 62°C, 64°C, 66°C, 68°C, 70°C, 72°C, 74°C, 76°C or 78°C, etc.

[0032] Preferably, the time of the reaction in step (1) is 1.5-2 h, such as 1.55 h, 1.6 h, 1.65 h, 1.7 h, 1.75 h, 1.8 h, 1.85 h or 1.9 h, etc.

[0033] Preferably, the reaction temperature for reacting the prepolymer obtained in step (1) with the hydrophilic monomer in step (2) is 60-80°C, such as 62°C, 64°C, 66°C, 68°C, 70°C, 72°C, 74°C, 76°C or 78°C, etc.

[0034] Preferably, the reaction temperature for adding the small molecule chain extender and optionally the solvent for reaction in step (2) is 60-80°C, such as 62°C, 64°C, 66°C, 68°C, 70°C, 72°C, 74°C, 76°C or 78°C, etc.

[0035] As a preferred technical solution of the present invention, the method for preparing the acid-resistant aqueous polyurethane slurry includes the following steps:

[0036] (1) React polymer diol, diisocyanate and a catalyst at 70-80°C for 1.5-2 h, use the di-n-butylamine method to measure that the mass percentage content of -NCO in the system reaches the theoretical value, stop the reaction, and obtain a prepolymer;

[0037] (2) Continuously react the prepolymer and the hydrophilic monomer obtained in step (1) at 70 - 80 °C. Use the dibutylamine method to determine that the mass percentage content of -NCO in the system reaches the theoretical value. Then add a small molecule chain extender and a solvent and continue the reaction at 70 - 80 °C. Use the dibutylamine method to determine that the mass percentage content of -NCO in the system is 0. Then add water for dispersion and remove the solvent by vacuum distillation to obtain the acid-resistant aqueous polyurethane sizing agent.

[0038] In the third aspect, the present invention provides a textile sizing agent, which comprises the acid-resistant aqueous polyurethane sizing agent as described in the first aspect and starch.

[0039] Preferably, the mass percentage content of the acid-resistant aqueous polyurethane sizing agent in the textile sizing agent is 5 - 15%, such as 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13% or 14%, etc.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] (1) The raw materials for preparing the acid-resistant aqueous polyurethane sizing agent provided by the present invention include a combination of polymer diol, diisocyanate, hydrophilic monomer, small molecule chain extender, catalyst and water, and the hydrophilic monomer includes a combination of sodium 3-hydroxypropanesulfonate and ethoxy-terminated polyethylene glycol; by selecting sodium 3-hydroxypropanesulfonate and ethoxy-terminated polyethylene glycol as the hydrophilic monomer, the finally obtained polyurethane sizing agent has excellent hydrophilicity and acid resistance, and has high water solubility under acidic conditions, and is suitable for use as a textile sizing agent.

[0042] (2) By further optimizing the raw materials for preparing the acid-resistant aqueous polyurethane sizing agent provided by the present invention, the viscosity of the obtained acid-resistant aqueous polyurethane sizing agent can be 7.8 - 9.1 mPa·s, and the viscosity is appropriate; the light transmittance before adjusting the pH value is 80.2 - 86.3%, and the appearance is light yellow semi-transparent state, and the light transmittance after adjusting the pH value is 77.3 - 83.7%. Specific Embodiments

[0043] The technical solutions of the present invention will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0044] Some raw material information involved in the specific embodiments of the present invention is as follows:

[0045] Polypropylene glycol: The number average molecular weight is 1000, and it is sourced from Jiangsu Coast Petrochemical Co., Ltd.;

[0046] Ethoxy-terminated polyglycol: number-average molecular weight is 1000, sourced from Perstorp AB, Sweden.

[0047] Example 1

[0048] An acid-resistant aqueous polyurethane sizing agent, and its preparation method includes the following steps:

[0049] (1) Pour 0.35 mol of polypropylene glycol and 1 mol of toluene diisocyanate (TDI) into a four-necked flask equipped with a condenser reflux tube, electric stirrer, thermometer, and nitrogen protective gas. Add dibutyltin dilaurate accounting for 0.05% of the mass percentage of all reaction raw materials, and react at 75 °C for 1.75 h. Use the dibutylamine method to determine that the mass percentage of -NCO in the system reaches the theoretical value to obtain a prepolymer.

[0050] (2) Add 0.35 mol of hydrophilic monomer (composed of sodium dihydroxypropyl sulfonate and ethoxy-terminated polyethylene glycol with a mass ratio of 15:1) to the prepolymer obtained in step (1). Continue to react at 75 °C until the mass percentage of -NCO in the system reaches the theoretical value. Add a small amount of acetone for dilution, then add 0.3 mol of 1,4-butanediol and continue to react at 75 °C. Use the dibutylamine method to determine that the mass percentage of -NCO in the system is 0. Then add 1000 g of deionized water for dispersion, and remove acetone by vacuum distillation to obtain the acid-resistant aqueous polyurethane sizing agent.

[0051] Example 2

[0052] An acid-resistant aqueous polyurethane sizing agent, and its preparation method includes the following steps:

[0053] (1) Pour 0.3 mol of polypropylene glycol and 1 mol of toluene diisocyanate (TDI) into a four-necked flask equipped with a condenser reflux tube, electric stirrer, thermometer, and nitrogen protective gas. Add dibutyltin dilaurate accounting for 0.02% of the mass percentage of all reaction raw materials, and react at 80 °C for 2 h. Use the dibutylamine method to determine that the mass percentage of -NCO in the system reaches the theoretical value to obtain a prepolymer.

[0054] (2) Add 0.4 mol of hydrophilic monomer (composed of sodium dihydroxypropyl sulfonate and ethoxy-terminated polyethylene glycol with a mass ratio of 5:1) to the prepolymer obtained in step (1). Continue to react at 80 °C until the mass percentage of -NCO in the system reaches the theoretical value. Add a small amount of acetone for dilution, then add 0.3 mol of 1,4-butanediol and continue to react at 80 °C. Use the dibutylamine method to determine that the mass percentage of -NCO in the system is 0. Then add 1000 g of deionized water for dispersion, and remove acetone by vacuum distillation to obtain the acid-resistant aqueous polyurethane sizing agent.

[0055] Example 3

[0056] An acid-resistant aqueous polyurethane sizing agent, and its preparation method includes the following steps:

[0057] (1) Pour 0.3 mol of polypropylene glycol and 1 mol of toluene diisocyanate (TDI) into a four-necked flask equipped with a condenser reflux tube, electric stirrer, thermometer, and nitrogen protection gas. Add stannous octoate accounting for 0.1% of the mass percentage of all reaction raw materials, and react at 70 °C for 1.5 h. Use the di-n-butylamine method to determine that the mass percentage of -NCO in the system reaches the theoretical value to obtain a prepolymer;

[0058] (2) Add 0.3 mol of hydrophilic monomer (composed of sodium dihydroxypropyl sulfonate and ethoxy-terminated polyethylene glycol with a mass ratio of 20:1) to the prepolymer obtained in step (1), continue to react at 80 °C until the mass percentage of -NCO in the system reaches the theoretical value, add a small amount of acetone for dilution, then add 0.4 mol of 1,4-butanediol and continue to react at 70 °C. Use the di-n-butylamine method to determine that the mass percentage of -NCO in the system is 0, and then add 1000 g of deionized water for dispersion. Remove acetone by vacuum distillation to obtain the acid-resistant aqueous polyurethane sizing agent.

[0059] Example 4

[0060] An acid-resistant aqueous polyurethane sizing agent, the difference from Example 1 is only that the hydrophilic monomer is composed of sodium dihydroxypropyl sulfonate and ethoxy-terminated polyethylene glycol with a mass ratio of 5:1, and other components, dosages, and preparation methods are the same as those in Example 1.

[0061] Example 5

[0062] An acid-resistant aqueous polyurethane sizing agent, the difference from Example 1 is only that the hydrophilic monomer is composed of sodium dihydroxypropyl sulfonate and ethoxy-terminated polyethylene glycol with a mass ratio of 20:1, and other components, dosages, and preparation methods are the same as those in Example 1.

[0063] Example 6

[0064] An acid-resistant aqueous polyurethane sizing agent, the difference from Example 1 is only that the hydrophilic monomer is composed of sodium dihydroxypropyl sulfonate and ethoxy-terminated polyethylene glycol with a mass ratio of 4:1, and other components, dosages, and preparation methods are the same as those in Example 1.

[0065] Example 7

[0066] An acid-resistant aqueous polyurethane sizing agent, the difference from Example 1 is only that the hydrophilic monomer is composed of sodium dihydroxypropyl sulfonate and ethoxy-terminated polyethylene glycol with a mass ratio of 25:1, and other components, dosages, and preparation methods are the same as those in Example 1.

[0067] Example 8

[0068] An acid-resistant aqueous polyurethane sizing agent, which is only different from that of Example 1 in that the total addition amount of hydrophilic monomers is 0.5 mol, and other components, dosages and preparation methods are the same as those of Example 1.

[0069] Example 9

[0070] An acid-resistant aqueous polyurethane sizing agent, which is only different from that of Example 1 in that the total addition amount of hydrophilic monomers is 0.2 mol, and other components, dosages and preparation methods are the same as those of Example 1.

[0071] Comparative Example 1

[0072] An aqueous polyurethane sizing agent, which is only different from that of Example 1 in that sodium 3-sulfo-1,2-propanediol is not added, and the hydrophilic monomers are only composed of ethoxylated polyethylene glycol, and other components, dosages and preparation methods are the same as those of Example 1.

[0073] Comparative Example 2

[0074] An aqueous polyurethane sizing agent, which is only different from that of Example 1 in that ethoxylated polyethylene glycol is not added, and the hydrophilic monomers are only composed of sodium 3-sulfo-1,2-propanediol, and other components, dosages and preparation methods are the same as those of Example 1.

[0075] Comparative Example 3

[0076] An aqueous polyurethane sizing agent, which is only different from that of Example 1 in that dimethylolpropionic acid with an equimolar amount is used to replace sodium 3-sulfo-1,2-propanediol and ethoxylated polyethylene glycol, and other components, dosages and preparation methods are the same as those of Example 1.

[0077] Application Example 1

[0078] A textile sizing agent, the preparation method of which includes: mixing starch and an acid-resistant aqueous polyurethane sizing agent (Example 1) with a mass ratio of 9:1 to obtain the textile sizing agent.

[0079] Application Examples 2-9

[0080] A textile sizing agent, which is only different from that of Application Example 1 in that the acid-resistant aqueous polyurethane sizing agents obtained in Examples 2-9 are respectively used to replace the acid-resistant aqueous polyurethane sizing agent obtained in Example 1, and other components, dosages and preparation methods are the same as those of Application Example 1.

[0081] Comparative Application Examples 1-3

[0082] A textile sizing agent, which is only different from Application Example 1 in that the acid-resistant waterborne polyurethane sizing agents obtained from Comparative Examples 1 to 3 are respectively used to replace the acid-resistant waterborne polyurethane sizing agent obtained in Example 1, and other components, dosages and preparation methods are the same as those in Application Example 1.

[0083] Comparative Application Example 4

[0084] A textile sizing agent, which is only different from Application Example 1 in that water is used to replace the acid-resistant waterborne polyurethane sizing agent.

[0085] Performance test:

[0086] (1) Viscosity: Using an NDJ-79 rotary viscometer, measure the apparent viscosity of the polyurethane sizing agent slurry at 30°C; the specific test method includes: accurately weigh 20 g (accurate to 0.001 g) of the sample with dry weight, and prepare it into a polyurethane sizing agent with a solid content of 20% with water. After mixing evenly, it is to be measured; before using the NDJ-79 rotary viscometer to measure the viscosity, calibrate and zero the instrument, then adjust the hook on the rotating cylinder so that the upper end of the rotating cylinder does not expose the slurry surface and the lower end does not touch the bottom, and then move the measuring device left and right to make it in the center position. When the pointer is stable, start reading and record it; repeat the above test twice and take the average value as the apparent viscosity of the sample;

[0087] (2) Acid resistance and hydrophilicity test: Accurately weigh 20 g (accurate to 0.001 g) of the sample with dry weight, and prepare it into a polyurethane sizing agent with a solid content of 1% with water. Use a UV-visible spectrophotometer UV2100 to measure the light transmittance of the polyurethane sizing agent before and after adjusting the pH value to 5.5, and observe the change in its appearance state.

[0088] The waterborne polyurethane sizing agents provided in Examples 1 to 9 and Comparative Examples 1 to 3 were tested according to the above test methods, and the test results are shown in Table 1:

[0089] Table 1

[0090]

[0091] It can be seen from the data in Table 1 that:

[0092] The acid-resistant waterborne polyurethane sizing agent provided by the present invention has an appropriate viscosity, as well as excellent hydrophilicity and acid resistance;

[0093] Specifically: The viscosities of the acid-resistant aqueous polyurethane slurries provided in Examples 1 to 5 are 7.8 to 9.1 mPa·s, with appropriate viscosities; the light transmittance before adjusting the pH value is 80.2 to 86.3%, and the appearance is light yellow semi-transparent. The light transmittance after adjusting the pH value is 77.3 to 83.7%, and the appearance is light yellow semi-transparent or milky white slightly transparent. The relatively high light transmittance before and after adjusting the pH value indicates good compatibility with water, strong hydrophilicity, and a very low decrease in light transmittance after adjusting the pH value, indicating high acid resistance and still having good hydrophilicity under acidic conditions.

[0094] Comparing Example 1 with Comparative Examples 1 to 2, in Comparative Example 1, since sodium 3-sulfo-1,2-propanediol was not added, and in Comparative Example 2, ethoxy-terminated polyethylene glycol was not added, the resulting aqueous polyurethane slurry had a low light transmittance and the appearance changed to milky white or light yellow, indicating poor hydrophilicity.

[0095] Comparing Example 1 with Comparative Example 3, in Comparative Example 3, when dimethylolpropionic acid with an equimolar amount was used to replace sodium 3-sulfo-1,2-propanediol and ethoxy-terminated polyethylene glycol, the resulting aqueous polyurethane slurry had poor hydrophilicity and acid resistance, and stratification occurred after adjusting the pH value.

[0096] Comparing Example 1 with Examples 6 to 7 again, since the mass ratios of sodium 3-sulfo-1,2-propanediol and ethoxy-terminated polyethylene glycol in Examples 6 and 7 were not within the preferred ranges defined in the present invention, the hydrophilicity of the finally obtained polyurethane slurry was also affected.

[0097] Finally, comparing Example 1 with Examples 8 to 9, the addition amount of the hydrophilic monomer in Example 9 was too low, resulting in poor acid resistance and hydrophilicity of the polyurethane slurry, while in Example 8, due to the too high addition amount of the hydrophilic monomer, the abrasion resistance of the formed aqueous polyurethane film was poor and could not meet the usage requirements.

[0098] (3) Tensile strength and elongation at break: After the textile slurry forms a film and is balanced for 24 h, it is cut into strip specimens of 150×10 mm. First, use a fabric thickness gauge to measure their thickness and calculate their average thickness. Then, turn on the Zwick universal material testing machine to measure the tensile strength and elongation at break of the film; the measurement conditions are: the distance between the chucks of the testing machine is 100 mm, the moving speed of the chucks is 50 mm / min, the sample size is 20 strips, and take their average value;

[0099] (4) Abrasion resistance: After the textile slurry forms a film, the film is cut into strip specimens with a length of 220×10 mm and measured on a Zweigle yarn abrasion tester. The KP915C type sandpaper is selected, the mass of the applied weight is 30 g, the length of the part subjected to friction is 65 mm, the number of friction times is 1000 times, the sample size is 10 times, and take their average value.

[0100] The textile sizing agents provided in Application Examples 1-9 and Comparative Application Examples 1-4 were tested according to the above test method, and the test results are shown in Table 2:

[0101] Table 2

[0102] Breaking strength / MPa Elongation at break / % <![CDATA[Wear resistance / mg / cm 2 > Application Example 1 26.6 7.3 0.26 Application Example 2 27.3 7.1 0.30 Application Example 3 26.5 7.3 0.28 Application Example 4 27.8 6.2 0.33 Application Example 5 26.8 7.2 0.29 Application Example 6 28.5 5.8 0.37 Application Example 7 26.4 7.0 0.27 Application Example 8 24.1 11.3 0.63 Application Example 9 29.4 3.2 0.49 Comparative Application Example 1 28.6 3.0 0.45 Comparative Application Example 2 26.4 6.8 0.32 Comparative Application Example 3 29.2 3.6 0.43 Comparative Application Example 4 32.4 2.6 0.53

[0103] It can be seen from the data in Table 2 that:

[0104] The breaking strength of the textile sizing agents provided in Application Examples 1-9 after forming a sizing film is 24.1-29.4 MPa, the elongation at break is 3.2-11.3%, and the abrasion loss in the abrasion resistance test is 0.26-0.63 mg / cm 2 , having excellent comprehensive properties;

[0105] However, the textile sizing agents provided in Comparative Examples 1-4 have poor comprehensive properties after forming a sizing film and cannot balance high breaking strength, elongation at break and abrasion resistance.

[0106] The applicant declares that the present invention illustrates an acid-resistant aqueous polyurethane sizing agent and its preparation method and application through the above embodiments, but the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvement to the present invention, the equivalent replacement of each raw material of the products of the present invention, the addition of auxiliary components, the selection of specific methods, etc. all fall within the protection scope and the disclosure scope of the present invention.

Claims

1. An acid-resistant aqueous polyurethane sizing agent, characterized in that, The raw materials for preparing the acid-resistant aqueous polyurethane sizing agent include a combination of polymer diol, diisocyanate, hydrophilic monomer, small molecule chain extender, catalyst and water; The polymer diol is selected from polypropylene glycol; The number average molecular weight of the polypropylene glycol is 1000; The molar ratio of the total moles of the polymer diol, hydrophilic monomer and small molecule chain extender to the diisocyanate is 1:(1 - 1.5); Based on the total moles of the polymer diol, hydrophilic monomer and small molecule chain extender being 100 mol%, the addition amount of the hydrophilic monomer is 30 - 40 mol%; The hydrophilic monomer includes a combination of sodium 3-hydroxypropane sulfonate and ethoxy-terminated polyethylene glycol; The mass ratio of sodium 3-hydroxypropane sulfonate to ethoxy-terminated polyethylene glycol is (5 - 20):1; The number average molecular weight of the ethoxy-terminated polyethylene glycol is 1000.

2. The acid-resistant aqueous polyurethane sizing agent according to claim 1, wherein The diisocyanate is selected from toluene diisocyanate.

3. The acid-resistant aqueous polyurethane sizing agent according to claim 1, characterized in that The small molecule chain extender includes small molecule diol and / or small molecule diamine.

4. The acid-resistant aqueous polyurethane sizing agent according to claim 3, wherein The small molecule diol is selected from 1,4-butanediol.

5. The acid-resistant aqueous polyurethane sizing agent according to claim 1, characterized in that, Based on the total moles of the polymer diol, hydrophilic monomer and small molecule chain extender being 100 mol%, the addition amount of the polymer diol is 30 - 40 mol%.

6. The acid-resistant aqueous polyurethane sizing agent according to claim 1, characterized in that, Based on the total moles of the polymer diol, hydrophilic monomer and small molecule chain extender being 100 mol%, the addition amount of the small molecule chain extender is 30 - 40 mol%.

7. The acid-resistant aqueous polyurethane sizing agent according to claim 1, wherein Based on the total mass of the raw materials for preparing the acid-resistant aqueous polyurethane sizing agent being 100%, the addition amount of the catalyst is 0.02 - 0.1%.

8. The acid-resistant aqueous polyurethane sizing agent according to claim 1, characterized in that The catalyst is selected from any one or a combination of at least two of dibutyltin dilaurate, stannous octoate or bismuth neodecanoate.

9. The acid-resistant aqueous polyurethane sizing agent according to claim 1, wherein Based on the total mass of the raw materials for preparing the acid-resistant aqueous polyurethane sizing agent being 100%, the addition amount of water is 60 - 70%.

10. The acid-resistant aqueous polyurethane sizing agent according to claim 1, characterized in that, The raw materials for preparing the acid-resistant aqueous polyurethane sizing agent further include a solvent.

11. A method for preparing the acid-resistant aqueous polyurethane sizing agent according to any one of claims 1 to 10, characterized in that, The preparation method includes the following steps: (1) React the polymer diol, diisocyanate and catalyst to obtain a prepolymer; (2) React the prepolymer obtained in step (1) with the hydrophilic monomer, add the small molecule chain extender and the solvent for reaction, and then add water for dispersion, and remove the solvent to obtain the acid-resistant aqueous polyurethane sizing agent.

12. The preparation method according to claim 11, wherein The reaction temperature in step (1) is 60 - 80 °C.

13. The preparation method according to claim 11, characterized in that, The reaction time in step (1) is 1.5 - 2 h.

14. The preparation method according to claim 11, characterized in that, The reaction temperature for reacting the prepolymer obtained in step (1) with the hydrophilic monomer in step (2) is 60 - 80 °C.

15. The preparation method according to claim 11, characterized in that, The reaction temperature for adding the small molecule chain extender and the solvent for reaction in step (2) is 60 - 80 °C.

16. A textile sizing agent, characterized in that, The textile sizing agent includes the acid-resistant aqueous polyurethane sizing agent according to any one of claims 1 - 10 and starch.

17. The textile sizing agent according to claim 16, characterized in that, The mass percentage content of the acid-resistant aqueous polyurethane sizing agent in the textile sizing agent is 5 - 15%.

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