Modified cationic aqueous polyurethane dispersion, its preparation method and application

Abstract

The present invention relates to a modified cationic aqueous polyurethane dispersion, a preparation method thereof and an application thereof. Among them, the preparation method of the modified cationic aqueous polyurethane dispersion includes the following steps: preparing a cationic polyurethane prepolymer; reacting the cationic polyurethane prepolymer with a hydroxyacrylate monomer to obtain a first modified cationic polyurethane prepolymer; adding an alkyl acrylate monomer, an emulsifier, a vinyl chloride monomer and an initiator to the first modified cationic polyurethane prepolymer and reacting to obtain a second modified cationic polyurethane prepolymer; adding a neutralizing agent to the second modified cationic polyurethane prepolymer to adjust it to an acidic state, and then through shear emulsification and solvent removal, a modified cationic aqueous polyurethane dispersion is obtained. When the modified cationic aqueous polyurethane dispersion prepared by the present invention is used, it can be uniformly and firmly dispersed on the surface of a textile substrate, and has excellent water repellency, washability and peel strength.

Description

Technical Field

[0001] The present invention relates to the technical field of fabric finishing agents, and particularly to a modified cationic aqueous polyurethane dispersion, a preparation method thereof, and an application thereof. Background Art

[0002] Water repellents are a type of fabric functional finishing agent and are widely used in textile fields such as home furnishings, umbrellas, tents, and shoe materials. At present, fluorine-free water repellents have been gradually promoted and used in textile substrate fields such as sportswear and sofa fabrics due to their characteristics of being green and environmentally friendly and having good waterproof performance. However, when traditional fluorine-free water repellents are used for finishing textile substrates, they are often difficult to be uniformly and firmly dispersed on the surface of textile substrates, resulting in defects such as poor water repellent effect, poor washability, and low peel strength. Summary of the Invention

[0003] Based on this, in view of the above problems, it is necessary to provide a modified cationic aqueous polyurethane dispersion, a preparation method thereof, and an application thereof. When the modified cationic aqueous polyurethane dispersion prepared by the preparation method is used, it can be uniformly and firmly dispersed on the surface of textile substrates, and has excellent water repellent effect, washability, and peel strength.

[0004] A preparation method of a modified cationic aqueous polyurethane dispersion includes the following steps:

[0005] Perform dehydration treatment on the polymer polyol;

[0006] Add a solvent, a diisocyanate, and a catalyst to the dehydrated polymer polyol for a prepolymerization reaction, and then add a cationic chain extender for a chain extension reaction to obtain a cationic polyurethane prepolymer;

[0007] React the cationic polyurethane prepolymer with a hydroxyacrylate monomer to obtain a first modified cationic polyurethane prepolymer;

[0008] Add an alkyl acrylate monomer, an emulsifier, a vinyl chloride monomer, and an initiator to the first modified cationic polyurethane prepolymer and react to obtain a second modified cationic polyurethane prepolymer;

[0009] Add a neutralizing agent to the second modified cationic polyurethane prepolymer to adjust it to an acidic state, and then perform shear emulsification and remove the solvent to obtain a modified cationic aqueous polyurethane dispersion.

[0010] In one embodiment, in the step of adding an alkyl acrylate monomer, an emulsifier, a vinyl chloride monomer, and an initiator to the first modified cationic polyurethane prepolymer and reacting, the alkyl acrylate monomer is first added to carry out free polymerization with the first modified cationic polyurethane prepolymer, and then the vinyl chloride monomer is added to continue the reaction.

[0011] In one embodiment, the hydroxyacrylate monomer is selected from one or more of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, and hydroxybutyl acrylate;

[0012] And / or, the alkyl acrylate monomer is selected from one or more of laurate, hexadecyl acrylate, octadecyl acrylate, and docosyl acrylate;

[0013] And / or, the emulsifier is selected from cationic emulsifiers, and the cationic emulsifier is selected from one or more of dodecyl trimethyl ammonium chloride, cetyl trimethyl ammonium chloride, or octadecyl trimethyl ammonium chloride.

[0014] In one embodiment, a neutralizing agent is added to the second modified cationic polyurethane prepolymer and adjusted to a pH of 3-6;

[0015] And / or, the neutralizing agent is selected from one of glacial acetic acid, citric acid, or acetic anhydride.

[0016] In one embodiment, in the step of dehydrating the polymer polyol, the temperature is 110°C - 130°C and the time is 1h - 2h.

[0017] In one embodiment, in the prepolymerization reaction of adding a solvent, a diisocyanate, and a catalyst to the dehydrated polymer polyol, the dehydrated polymer polyol is first cooled to 55°C - 65°C. During the prepolymerization reaction, the prepolymerization reaction temperature is 55°C - 65°C and the prepolymerization reaction time is 3h - 4h. During the chain extension reaction, the chain extension reaction temperature is 55°C - 60°C and the chain extension reaction time is 0.5h - 1h.

[0018] In one embodiment, the diisocyanate is selected from one or more of toluene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, and tetramethylbenzene dimethyl diisocyanate;

[0019] And / or, the cationic chain extender is selected from diethanolamine or N-methyldiethanolamine;

[0020] And / or, the polymer polyol is selected from one of polyester diol, polyether polyol, or polycarbonate diol.

[0021] In one embodiment, the amounts of each component are as follows by mass percentage: 10%-35% of the polymer polyol, 8%-24% of the diisocyanate, 1.5%-8% of the cationic chain extender, 2%-10% of the hydroxyacrylate monomer, 18%-40% of the alkyl acrylate monomer, 2%-10% of the emulsifier, 3%-12% of the vinyl chloride monomer, and 3%-9.2% of the neutralizing agent.

[0022] A modified cationic aqueous polyurethane dispersion, which is prepared by the preparation method of the modified cationic aqueous polyurethane dispersion described above.

[0023] An application of the modified cationic aqueous polyurethane dispersion as described above as a water repellent in textiles.

[0024] In the present invention, a modified cationic aqueous polyurethane dispersion is prepared by introducing a hydroxyacrylate monomer, an alkyl acrylate monomer, and a vinyl chloride monomer into the molecular chain of a cationic polyurethane prepolymer. It has better film-forming properties and can be uniformly and firmly dispersed on the surface of a textile substrate during use, having excellent water repellency, washability, and peel strength. Description of the Drawings

[0025] Figure 1 It is the Fourier infrared spectrum of the modified cationic aqueous polyurethane dispersion prepared in Example 1 of the present invention. Detailed Embodiments

[0026] The modified cationic aqueous polyurethane dispersion provided by the present invention, its preparation method and application will be further described below.

[0027] The preparation method of the modified cationic aqueous polyurethane dispersion provided by the present invention includes the following steps:

[0028] Perform dehydration treatment on the polymer polyol;

[0029] Add a solvent, a diisocyanate, and a catalyst to the dehydrated polymer polyol for prepolymerization reaction, and then add a cationic chain extender for chain extension reaction to obtain a cationic polyurethane prepolymer;

[0030] React the cationic polyurethane prepolymer with a hydroxyacrylate monomer to obtain a first modified cationic polyurethane prepolymer;

[0031] Add an alkyl acrylate monomer, an emulsifier, a vinyl chloride monomer, and an initiator to the first modified cationic polyurethane prepolymer and react to obtain a second modified cationic polyurethane prepolymer;

[0032] A neutralizing agent is added to the second modified cationic polyurethane prepolymer to adjust it to an acidic state, and then it is subjected to shear emulsification and solvent removal to obtain a modified cationic aqueous polyurethane dispersion.

[0033] Specifically, in the present invention, reacting the cationic polyurethane prepolymer with a hydroxyacrylate monomer can introduce active carbon-carbon double bonds into the molecular chain of the cationic polyurethane prepolymer. These carbon-carbon double bonds can undergo free radical polymerization with the subsequent introduced alkyl acrylate monomers, enabling the alkyl acrylate monomers to be graft copolymerized as hydrophobic groups onto the molecular chain of the first modified cationic polyurethane prepolymer, thereby improving the compatibility between the alkyl acrylate and the first modified cationic polyurethane prepolymer and enhancing the water repellency effect of the modified cationic aqueous polyurethane dispersion.

[0034] Meanwhile, the introduction of vinyl chloride monomer enables vinyl chloride monomer to undergo free radical polymerization by itself or with alkyl acrylate monomers under the action of an initiator. A large number of polar chlorine atoms in the polyvinyl chloride formed by free radical polymerization can form hydrogen bonds with the hydrogen atoms of the urethane groups in the polyurethane component, causing polyvinyl chloride to be graft copolymerized onto the main chain of the molecular chain of the first modified cationic polyurethane prepolymer containing hydrophobic groups, thereby improving the compatibility between the alkyl acrylate monomers, vinyl chloride monomer, and the polyurethane molecular chain interface, and further enhancing the film-forming effect of the modified cationic aqueous polyurethane dispersion.

[0035] In the present invention, the graft copolymerization of vinyl chloride monomer, on the one hand, can form non-covalent interactions with carboxyl groups, amino groups, etc. on the surface of the textile substrate, that is, it can undergo non-covalent binding with the textile substrate surface together with the polyurethane structure, synergistically increasing the interaction force with the textile substrate and improving the mechanical bonding strength of the textile, thereby enhancing the wash resistance and anti-peeling strength of the modified cationic aqueous polyurethane dispersion; on the other hand, it can effectively weaken the flipping of the long-chain alkanes in the poly-chain segments of the modified cationic aqueous polyurethane dispersion structure, thereby increasing the stability of the hydrophobic groups (alkyl acrylate copolymers) in the modified cationic aqueous polyurethane dispersion structure; and combined with the excellent film-forming property of polyurethane, it further weakens the sliding of the poly-chain segment alkanes on the surface of the textile substrate, enabling the hydrophobic groups to be firmly dispersed on the surface of the textile substrate. Therefore, the modified cationic aqueous polyurethane dispersion of the present invention has better film-forming property, can be evenly and firmly dispersed on the surface of the textile substrate, and has excellent water repellency, wash resistance, and anti-peeling strength.

[0036] In addition, considering that the textile substrate shows a negative charge in water, making it impossible for conventional anionic polyurethane products to be tightly adsorbed to the textile substrate, the modified cationic aqueous polyurethane dispersion of the present invention, due to its positive charge, can effectively avoid the problem that conventional anionic polyurethane products cannot be tightly adsorbed to the fabric, thus being more conducive to the film-forming uniformity of the modified cationic aqueous polyurethane dispersion on the surface of the textile substrate, and further improving its wash resistance and peel strength.

[0037] It can be seen that the modified cationic aqueous polyurethane dispersion prepared by the method of the present invention has better film-forming properties by introducing hydroxyacrylate monomers, alkane acrylate monomers, and vinyl chloride monomers into the cationic polyurethane molecular chain. When in use, it can be uniformly and firmly dispersed on the surface of the textile substrate, having excellent water repellency, wash resistance, and peel strength.

[0038] Considering that the reactivity ratios of alkane acrylate monomers and vinyl chloride monomers in the polyurethane molecular chain vary greatly, in order to ensure the smooth graft copolymerization of vinyl chloride monomers, preferably, in the step of adding alkane acrylate monomers, emulsifiers, vinyl chloride monomers, and initiators to the first modified cationic polyurethane prepolymer and reacting, the alkane acrylate monomers are first added to freely polymerize with the first modified cationic polyurethane prepolymer, and then the vinyl chloride monomers are added to continue the reaction. This setting enables the alkane acrylate monomers to copolymerize to the side ends of the first modified cationic polyurethane prepolymer, and then the vinyl chloride monomers can be smoothly introduced into the molecular chain of the first modified cationic polyurethane prepolymer. At the same time, the introduction of vinyl chloride monomers can introduce more carbon-carbon double bonds into the first modified cationic polyurethane prepolymer, and the introduction of these carbon-carbon double bonds can polymerize with more alkane acrylate monomers, thereby increasing the content of alkane acrylate monomers in the modified cationic aqueous polyurethane dispersion, and further improving the water repellency of the modified cationic aqueous polyurethane dispersion.

[0039] In order to better ensure the copolymerization of alkane acrylate monomers and vinyl chloride monomers on the second modified cationic polyurethane prepolymer and the free radical polymerization reaction between them, the first modified cationic polyurethane prepolymer is placed in a high-pressure reaction kettle, and in a protective atmosphere, a solvent is added and stirred evenly to adjust the viscosity of the reaction system. The alkane acrylate monomers and the emulsifiers are added, and the vinyl chloride monomers are introduced. The temperature is raised to 60°C - 65°C, and the initiator dissolved in the solvent is added, and the reaction is carried out for 2h - 3h to obtain the second modified cationic polyurethane prepolymer. In this step, by adding emulsifiers, the stability of the whole system can be ensured, preventing the system from stratifying and precipitating.

[0040] Preferably, the initiator is gradually added dropwise to the reaction system, and the dropping time is 0.5 h - 1 h. After the dropping is completed, the system continues to react for 1 h - 2 h. By adopting the method of gradually adding the initiator dropwise, the free radical polymerization between the alkane acrylate monomer, vinyl chloride monomer and cationic polyurethane prepolymer can be effectively ensured, and the chemical bond combination between the alkane acrylate monomer and the polyurethane molecular chain, as well as the graft copolymerization of polyvinyl chloride on the polyurethane molecular chain containing hydrophobic groups can be better realized.

[0041] Preferably, the solvent can be one of acetone, methyl ethyl ketone or N-methylpyrrolidone. Preferably, it is acetone in the present invention. Further, the protective atmosphere is nitrogen or other inert gases.

[0042] Preferably, the hydroxyacrylate monomer is selected from one or more of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate and hydroxybutyl acrylate.

[0043] Preferably, the alkane acrylate monomer is selected from acrylate compounds containing branched chains with a carbon number greater than or equal to 8. Further, the alkane acrylate monomer is selected from one or more of laurate, hexadecyl acrylate, octadecyl acrylate and docosyl acrylate.

[0044] Preferably, the emulsifier is selected from cationic emulsifiers, and the cationic emulsifier is selected from one or more of dodecyl trimethyl ammonium chloride, cetyl trimethyl ammonium chloride or octadecyl trimethyl ammonium chloride. While ensuring the stability of the system, this emulsifier can further strengthen the positive charge in the system, making the polyurethane dispersion have a strong positive charge, and thus having a tight adsorption with the surface of the textile substrate in water.

[0045] In order to ensure the stability of the modified cationic aqueous polyurethane dispersion and strengthen the positive charge of the entire polyurethane system. Preferably, the second modified cationic polyurethane prepolymer is placed in a high-speed shear kettle, the pH is adjusted to 3 - 6 by adding a neutralizing agent to the second modified cationic polyurethane prepolymer, and deionized water is added for emulsification at a shear speed of 3000 rpm - 5000 rpm, and then the solvent is removed by low-pressure distillation and filtered to obtain the modified cationic aqueous polyurethane dispersion. Further, the neutralizing agent is selected from one of glacial acetic acid, citric acid or acetic anhydride.

[0046] Preferably, during the dehydration treatment of the polymer polyol, the polymer polyol is placed in a flask, and then vacuum dehydrated at a dehydration temperature of 110 °C - 130 °C for 1 h - 2 h to obtain the dehydrated polymer polyol; through vacuum dehydration, the consumption of the NCO functional group in the component diisocyanate in the subsequent reaction by the removal of water can be avoided.

[0047] Preferably, in the prepolymerization reaction of adding a solvent, a diisocyanate and a catalyst to the dehydrated polymer polyol, the dehydrated polymer polyol is first cooled to 55°C - 65°C, and this setting can avoid the influence of high temperature on the subsequently added solvent and other reaction raw materials; then the solvent is added to the dehydrated polymer polyol, and the solvent is preferably acetone.

[0048] Preferably, in the process of the prepolymerization reaction, the prepolymerization reaction temperature is 55°C - 65°C, and the prepolymerization reaction time is 3h - 4h. In the process of the chain extension reaction, the chain extension reaction temperature is 55°C - 60°C, and the chain extension reaction time is 0.5h - 1h. The limitation of the reaction temperature and reaction time can enable sufficient reaction between each component.

[0049] Preferably, the diisocyanate is selected from one or more of toluene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, and tetramethylxylylene diisocyanate.

[0050] Preferably, the cationic chain extender is selected from diethanolamine or N-methyldiethanolamine. Selecting the above-mentioned small molecule cationic chain extender can ensure the formation of a cationic polyurethane prepolymer, and further ensure that the subsequently prepared modified cationic aqueous polyurethane dispersion is positively charged, which can better tightly adsorb on the surface of the textile substrate, thereby improving its wash resistance.

[0051] Preferably, the catalyst is selected from at least one of dibutyltin dilaurate and stannous octoate.

[0052] Preferably, the polymer polyol is selected from one of polyester diol, polyether polyol or polycarbonate diol; preferably, the molecular weight of the polymer polyol is 1000 - 3000. This setting helps the emulsification of the prepolymer formed in the subsequent reaction, and at the same time, avoids the introduction of too many hydrophilic groups into the polyurethane dispersion structure, which affects the water repellency.

[0053] In order to ensure that the modified cationic aqueous polyurethane dispersion is positively charged, has excellent water repellency and wash resistance, in the present invention, calculated by mass percentage, the dosage of each component is as follows: the polymer polyol 10% - 35%, the diisocyanate 8% - 24%, the cationic chain extender 1.5% - 8%, the hydroxyacrylate monomer 2% - 10%, the alkyl acrylate monomer 18% - 40%, the emulsifier 2% - 10%, the vinyl chloride monomer 3% - 12%, the neutralizer 3% - 9.2%.

[0054] Preferably, the dosage of the initiator in the present invention is 0.8%-3% of the total mass of the mixture of the hydroxyacrylate monomer, the alkane acrylate monomer, and the vinyl chloride monomer. The limitation of this dosage can ensure the free radical polymerization reaction of the above monomers and between the monomers. Further, the initiator is one or more of azodiisobutyronitrile, azodiisopentanenitrile, ammonium persulfate, and potassium persulfate.

[0055] In order to better introduce active carbon-carbon double bonds at the end of the cationic polyurethane prepolymer molecular chain and achieve the chemical bond combination between the subsequent first-modified cationic polyurethane prepolymer molecular chain and the alkane acrylate monomer, preferably, during the reaction of the cationic polyurethane prepolymer with the hydroxyacrylate monomer, the cationic polyurethane prepolymer is first stirred, and then the hydroxyacrylate monomer is gradually dropped in.

[0056] Preferably, during the addition of the neutralizing agent to the second-modified cationic polyurethane prepolymer, the second-modified cationic polyurethane prepolymer is first cooled to less than or equal to 30°C, continuously evacuated for 10 min - 20 min, and the unreacted vinyl chloride monomer is condensed and recovered. This setting can achieve the cyclic recovery of the vinyl chloride monomer.

[0057] The modified cationic aqueous polyurethane dispersion provided by the present invention is prepared by the preparation method of the modified cationic aqueous polyurethane dispersion described above. This modified cationic aqueous polyurethane dispersion has better film-forming properties. When in use, it can be evenly and firmly dispersed on the surface of the textile substrate, and has excellent water repellency, washability, and peel strength.

[0058] The application of the modified cationic aqueous polyurethane dispersion provided by the present invention as a water repellent in textiles. When the modified cationic aqueous polyurethane dispersion is applied as a water repellent in textiles, the textiles prepared by the present invention can have excellent water repellency, washability, and peel strength.

[0059] Hereinafter, the modified cationic aqueous polyurethane dispersion, its preparation method, and application will be further described through the following specific examples.

[0060] Example 1

[0061] Weigh 25 g of polyester diol into a four-necked flask, and conduct vacuum dehydration at a temperature of 110 °C. After 1 h of dehydration, cool down to 60 °C, add 24 g of acetone, stir evenly, and then, under the protection of a nitrogen atmosphere, add 16.8 g of isophorone diisocyanate and two drops of stannous octoate, and react for 3 h; under heat preservation, add 4.9 g of N-methyldiethanolamine, and continue to react for 0.5 h to obtain a cationic polyurethane prepolymer. Then, raise the temperature to 65 °C, gradually dropwise add 5.8 g of hydroxypropyl acrylate. After the dropwise addition, keep stirring at a constant temperature and continue to react for 1 h to obtain a transparent first-modified cationic polyurethane prepolymer. Next, place the obtained transparent first-modified cationic polyurethane prepolymer into a high-pressure reactor. Under the protection of a nitrogen atmosphere, after adding 20 g of acetone as a supplement, add 28.8 g of octadecyl acrylate and 5.5 g of octadecyltrimethylammonium chloride, evacuate, introduce 8.8 g of vinyl chloride monomer, raise the temperature to 65 °C, gradually dropwise add 0.2 g of azobisisobutyronitrile dissolved in acetone solvent. After the dropwise addition is completed, react for 2.5 h to obtain a second-modified cationic polyurethane prepolymer. Then, cool down to below 30 °C, continuously evacuate for 15 min, and condense and recover the unreacted vinyl chloride monomer; at the same time, transfer the obtained second-modified cationic polyurethane prepolymer to a high-speed shearing kettle, add 7.4 g of glacial acetic acid and stir evenly, adjust the pH to 3, and at a rotation speed of 3000 rpm, add 268 g of deionized water for emulsification, and remove acetone under low pressure, and filter to obtain a light yellow modified cationic aqueous polyurethane dispersion.

[0062] In the present invention, a Fourier transform infrared (FT-IR) spectrometer was used to perform infrared transmission scanning on the modified cationic aqueous polyurethane dispersion prepared in Example 1, and the Figure 1 obtained Fourier transform infrared spectrum diagram is shown. From Figure 1 it can be seen that a C-Cl stretching vibration peak appears at 692 cm -1 , and a symmetric stretching vibration peak of C-H in polyvinyl chloride is at 1435 cm -1 ; the N-H vibration absorption peak is at 3330 cm -1 , and the combined absorption peak of N-H bending vibration and C-N stretching vibration in the urethane structure is at 1530 cm -1 ; the C-H stretching vibration peaks are at 2850 cm -1 and 2960 cm -1 , and the C=O stretching vibration peak is at 1730 cm -1 . Thus, it can be known that the modified cationic aqueous polyurethane dispersion prepared in Example 1 of the present invention has been successfully synthesized.

[0063] Example 2

[0064] Weigh 25 g of polyester diol into a four-necked flask, carry out vacuum dehydration at a temperature of 110 °C. After 1 h of dehydration, cool down to 60 °C, add 24 g of acetone, stir evenly, and then, under the protection of a nitrogen atmosphere, add 16.8 g of isophorone diisocyanate and two drops of stannous octoate, and react for 3 h. Under heat preservation, add 4.9 g of N-methyldiethanolamine and continue to react for 0.5 h to obtain a cationic polyurethane prepolymer. Then, raise the temperature to 65 °C, gradually add dropwise 5.8 g of hydroxypropyl acrylate. After the addition is complete, keep stirring at a constant temperature and continue to react for 1 h to obtain a transparent first-modified cationic polyurethane prepolymer. Next, place the obtained transparent first-modified cationic polyurethane prepolymer in a high-pressure reactor. Under the protection of a nitrogen atmosphere, after adding 20 g of acetone as a supplement, add 16.4 g of octadecyl acrylate and 5.5 g of octadecyltrimethylammonium chloride, evacuate, introduce 8.8 g of vinyl chloride monomer, raise the temperature to 60 °C, gradually add dropwise 0.2 g of azobisisobutyronitrile dissolved in acetone solvent. After the addition is complete, react for 2 h to obtain a second-modified cationic polyurethane prepolymer. Then, cool down to below 30 °C, continuously evacuate for 15 min, and condense and recover the unreacted vinyl chloride monomer. At the same time, transfer the obtained second-modified cationic polyurethane prepolymer to a high-speed shearing kettle, add 7.4 g of glacial acetic acid and stir evenly, adjust the pH to 3, and at a rotation speed of 3000 rpm, add 268 g of deionized water for emulsification, and remove acetone under low pressure, and filter to obtain a light yellow modified cationic aqueous polyurethane dispersion.

[0065] Example 3

[0066] Weigh 25 g of polyester diol into a four-necked flask, and conduct vacuum dehydration at a temperature of 110 °C. After 1 h of dehydration, cool down to 60 °C, add 24 g of acetone, stir evenly, and then, under the protection of a nitrogen atmosphere, add 16.8 g of isophorone diisocyanate and two drops of stannous octoate, and react for 3 h. Under heat preservation, add 4.9 g of N-methyldiethanolamine and continue to react for 0.5 h to obtain a cationic polyurethane prepolymer. Then, raise the temperature to 65 °C, gradually add dropwise 5.8 g of hydroxypropyl acrylate. After the addition is complete, continue to stir at a constant temperature and react for 1 h to obtain a transparent first-modified cationic polyurethane prepolymer. Next, place the obtained transparent first-modified cationic polyurethane prepolymer into a high-pressure reactor. Under the protection of a nitrogen atmosphere, after adding 20 g of acetone, add 28.8 g of octadecyl acrylate and 2.5 g of octadecyltrimethylammonium chloride, evacuate, introduce 8.8 g of vinyl chloride monomer, raise the temperature to 60 °C, gradually add dropwise 0.2 g of azobisisobutyronitrile dissolved in acetone solvent. After the addition is complete, react for 2 h to obtain a second-modified cationic polyurethane prepolymer. Then, cool down to below 30 °C, continuously evacuate for 15 min, and condense and recover the unreacted vinyl chloride monomer; at the same time, transfer the obtained second-modified cationic polyurethane prepolymer to a high-speed shearing kettle, add 7.4 g of glacial acetic acid and stir evenly, adjust the pH to 3, and at a rotation speed of 3000 rpm, add 268 g of deionized water for emulsification, and remove acetone under low pressure, and filter to obtain a light yellow modified cationic aqueous polyurethane dispersion.

[0067] Example 4

[0068] Weigh 13.6 g of polyester diol into a four-necked flask, conduct vacuum dehydration at a temperature of 110 °C. After 1 h of dehydration, cool down to 60 °C, add 24 g of acetone, stir evenly, and then, under the protection of a nitrogen atmosphere, add 9.7 g of isophorone diisocyanate and two drops of stannous octoate, and react for 3 h; under heat preservation, add 4.9 g of N-methyldiethanolamine and continue to react for 0.5 h to obtain a cationic polyurethane prepolymer. Then, raise the temperature to 65 °C, gradually dropwise add 5.8 g of hydroxypropyl acrylate. After the dropwise addition is completed, keep stirring at a constant temperature and continue to react for 1 h to obtain a transparent first-modified cationic polyurethane prepolymer. Next, place the obtained transparent first-modified cationic polyurethane prepolymer in a high-pressure reactor. Under the protection of a nitrogen atmosphere, after adding 20 g of acetone as a supplement, add 28.8 g of octadecyl acrylate and 5.5 g of octadecyltrimethylammonium chloride, evacuate the air, introduce 8.8 g of vinyl chloride monomer, raise the temperature to 60 °C, gradually dropwise add 0.2 g of azobisisobutyronitrile dissolved in acetone solvent. After the dropwise addition is completed, react for 2 h to obtain a second-modified cationic polyurethane prepolymer. Then, cool down to below 30 °C, continuously evacuate the air for 15 min, and condense and recover the unreacted vinyl chloride monomer; at the same time, transfer the obtained second-modified cationic polyurethane prepolymer to a high-speed shearing kettle, add 7.4 g of glacial acetic acid and stir evenly, adjust the pH to 3, and at a rotation speed of 3000 rpm, add 268 g of deionized water for emulsification, and remove acetone under low pressure, and filter to obtain a light yellow modified cationic aqueous polyurethane dispersion.

[0069] Example 5

[0070] Weigh 25 g of polyester diol into a four-necked flask, and conduct vacuum dehydration at a temperature of 110 °C. After 1 h of dehydration, cool down to 60 °C, add 24 g of acetone, stir evenly, and then, under the protection of a nitrogen atmosphere, add 16.8 g of isophorone diisocyanate and two drops of stannous octoate, and react for 3 h; under heat preservation, add 4.9 g of N-methyldiethanolamine, and continue to react for 0.5 h to obtain a cationic polyurethane prepolymer. Then, raise the temperature to 65 °C, gradually add dropwise 5.8 g of hydroxypropyl acrylate. After the addition is complete, continue to stir at a constant temperature and react for 1 h to obtain a transparent first-modified cationic polyurethane prepolymer. Next, place the obtained transparent first-modified cationic polyurethane prepolymer into a high-pressure reactor, under the protection of a nitrogen atmosphere, add 20 g of acetone after supplementation, then add 28.8 g of octadecyl acrylate and 5.5 g of octadecyl trimethyl ammonium chloride, evacuate the air, introduce 4.2 g of vinyl chloride monomer, raise the temperature to 65 °C, gradually add dropwise 0.2 g of azobisisobutyronitrile dissolved in acetone solvent. After the addition is complete, react for 2 h to obtain a second-modified cationic polyurethane prepolymer. Then, cool down to below 30 °C, continuously evacuate the air for 15 min, and condense and recover the unreacted vinyl chloride monomer; at the same time, transfer the obtained second-modified cationic polyurethane prepolymer to a high-speed shearing kettle, add 7.4 g of glacial acetic acid and stir evenly, adjust the pH to 3, and at a rotation speed of 3000 rpm, add 268 g of deionized water for emulsification, and remove acetone under low pressure, and filter to obtain a light yellow modified cationic aqueous polyurethane dispersion.

[0071] Example 6

[0072] Weigh 24 g of polycarbonate diol into a four-necked flask, carry out vacuum dehydration at 110 °C. After 1.5 h of dehydration, cool down to 60 °C, add 25 g of acetone, stir evenly, and then, under the protection of nitrogen atmosphere, add 15.5 g of toluene diisocyanate and two drops of dibutyltin dilaurate, and react for 3.5 h; keep the temperature, add 7.5 g of diethanolamine, and continue to react for 0.8 h to obtain a cationic polyurethane prepolymer. Then, raise the temperature to 65 °C, gradually add dropwise 4 g of hydroxyethyl acrylate. After the addition is complete, keep stirring at a constant temperature and continue to react for 1.3 h to obtain a transparent first-modified cationic polyurethane prepolymer. Next, place the obtained transparent first-modified cationic polyurethane prepolymer into a high-pressure reactor. Under the protection of nitrogen atmosphere, after adding 25 g of acetone, add 30 g of hexadecyl acrylate and 5.5 g of cetyltrimethylammonium chloride, evacuate, introduce 7.5 g of vinyl chloride monomer, raise the temperature to 65 °C, gradually add dropwise 0.2 g of azobisisobutyronitrile dissolved in acetone solvent. After the addition is complete, react for 2.6 h to obtain a second-modified cationic polyurethane prepolymer. Then, cool down to below 30 °C, continuously evacuate for 15 min, and condense and recover the unreacted vinyl chloride monomer; at the same time, transfer the obtained second-modified cationic polyurethane prepolymer to a high-speed shearing kettle, add 6.5 g of citric acid and stir evenly, adjust the pH to 4.5, and at a rotation speed of 3000 rpm, add 270 g of deionized water for emulsification, and remove acetone under low pressure, and filter to obtain a light yellow modified cationic aqueous polyurethane dispersion.

[0073] Example 7

[0074] Compared with Example 1, the only difference is that in Example 7, the obtained transparent first-modified cationic polyurethane prepolymer is placed into a high-pressure reactor. Under the protection of nitrogen atmosphere, after adding 20 g of acetone, add 28.8 g of octadecyl acrylate, 5.5 g of octadecyltrimethylammonium chloride and 0.2 g of azobisisobutyronitrile dissolved in acetone solvent, raise the temperature to 65 °C, after reacting for 1 h, introduce 8.8 g of vinyl chloride monomer, and continue to react for 1.5 h to obtain a second-modified cationic polyurethane prepolymer.

[0075] Comparative Example 1

[0076] Compared with Example 1, the only difference is that in Comparative Example 1, the obtained transparent first-modified cationic polyurethane prepolymer is placed into a high-pressure reactor. Under the protection of nitrogen atmosphere, after adding 20 g of acetone, introduce 8.8 g of vinyl chloride monomer, add 0.2 g of azobisisobutyronitrile dissolved in acetone solvent and 5.5 g of octadecyltrimethylammonium chloride, raise the temperature to 65 °C, after reacting for 1 h, then add 28.8 g of octadecyl acrylate, and continue to react for 1.5 h to obtain a second-modified cationic polyurethane prepolymer.

[0077] Comparative Example 2

[0078] Compared with Example 1, the only difference is that vinyl chloride monomer is not introduced in Comparative Example 2.

[0079] Comparative Example 3

[0080] Compared with Example 1, the only difference is that in Comparative Example 3, the anionic chain extender dimethylolbutyric acid is used to replace the cationic chain extender N-methyldiethanolamine.

[0081] The present invention measures the high-temperature stability of the polyurethane dispersions prepared in Examples 1-7. The specific method is as follows: Take the polyurethane dispersions prepared in Examples 1-7 with the same weight as samples, and uniformly place them statically in an oven at 55 °C. After 14 days, observe whether there is stratification or precipitation. The test results are shown in Table 1.

[0082] Table 1 Results of high-temperature stability measurement

[0083]

[0084] It can be seen from the results in Table 1 that the modified cationic aqueous polyurethane dispersion obtained by the preparation method of the present invention has very good high-temperature storage stability. Combining Example 1 and Example 3, it can be known that when the amount of emulsifier is very small, it will have a great impact on the stability of the modified cationic aqueous polyurethane dispersion, resulting in stratification and precipitation during high-temperature storage.

[0085] Application performance test

[0086] The present invention takes the polyurethane dispersions prepared in Examples 1-7 and Comparative Examples 1-3, as well as the commercially available foreign sample fluorine-free water repellent R3, and dilutes them to 60 g / L respectively as working finishing liquids, a total of 11 portions; at the same time, take three kinds of fabrics, namely polyester pongee, taslon, and cotton twill, with the same size. Each kind of fabric is provided with 11 portions corresponding to the 11 portions of the working finishing liquid. Then, under the same conditions, the different kinds of fabrics are respectively placed in the 11 portions of the working finishing liquid for one dip and one nip, with the liquor pickup rate being 50-85%. After pre-drying at 80 °C for 6 minutes, then setting at 170 °C for 1 minute, and conditioning, the corresponding water-repellent fabrics are obtained.

[0087] The present invention respectively conducts water-repellent performance and peel strength performance tests on the corresponding water-repellent fabrics obtained from the polyester pongee, taslon, and cotton twill fabrics treated with the polyurethane dispersions prepared in Examples 1-7 and Comparative Examples 1-3 and the fluorine-free water repellent R3 as the finishing working liquid.

[0088] Among them, the present invention respectively conducts corresponding water repellency tests on the above-mentioned water-repellent fabrics according to the AATCC 22-2014 test standard, and conducts washability tests on the above-mentioned water-repellent fabrics according to the AATCC 135-2018t test standard. The test results of water repellency and washability are shown in Tables 2 and 3.

[0089] The present invention coats the above-obtained water-repellent fabrics with an automatic coating and sizing machine, wherein the sizing amount of the coating glue is maintained at 6-8 g / m 2 , pastes strips, and then conducts a peel strength performance test according to the FZ / T 01085-2018 test standard. The test results of the peel strength performance are shown in Tables 4 and 5.

[0090] Table 2

[0091]

[0092]

[0093] Table 3

[0094]

[0095] Table 4

[0096]

[0097] Table 5

[0098]

[0099]

[0100] It can be seen from the test results in Tables 2-3 and Tables 4-5 that after the surface of the textile substrate is finished with the modified cationic aqueous polyurethane dispersion prepared by the preparation method of the present invention, the water repellency effect is good, and it can still maintain 90 points after ten washes, with excellent washability, which is equivalent to the fluorine-free water repellent R3 of foreign samples. At the same time, the peel strength of the fabric finished with the modified cationic aqueous polyurethane dispersion of the present invention reaches more than 12 N in the subsequent coating test, and the peel performance is much better than that of the commercially available fluorine-free water repellent R3.

[0101] Specifically, combining the data of Example 1 and Example 7 shows that by defining the reaction sequence of alkane acrylate monomers and vinyl chloride monomers, it is beneficial to improve the water repellency, washability, and anti-peeling strength of the modified cationic aqueous polyurethane dispersion. At the same time, combining the data of Example 1 and Comparative Example 2 shows that the introduction of vinyl chloride monomers further improves the water repellency, washability, and anti-peeling strength of the modified cationic aqueous polyurethane dispersion. In addition, combining the data of Example 1 and Comparative Example 3 shows that the modified cationic aqueous polyurethane dispersion of the present invention has better close adsorption with the surface of textile substrates compared to conventional anionic polyurethane emulsions, and has better washability and anti-peeling strength.

[0102] It can be seen that the modified cationic aqueous polyurethane dispersion prepared by the method of the present invention has better film-forming properties by introducing hydroxyacrylate monomers, alkane acrylate monomers, and vinyl chloride monomers into the cationic polyurethane molecular chain. When in use, it can be evenly and firmly dispersed on the surface of textile substrates, not only having excellent water repellency, but also good washability and strong anti-peeling strength.

[0103] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered to be within the scope described in this specification.

[0104] The above-described embodiments merely represent several implementation manners of the present invention. Their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the invention patent should be subject to the appended claims.

Claims

1. A preparation method of a modified cationic aqueous polyurethane dispersion, characterized in that, It includes the following steps: Perform dehydration treatment on the polymer polyol; Add a solvent, a diisocyanate, and a catalyst to the dehydrated polymer polyol for prepolymerization reaction, and then add a cationic chain extender for chain extension reaction to obtain a cationic polyurethane prepolymer; React the cationic polyurethane prepolymer with a hydroxyacrylate monomer to obtain a first modified cationic polyurethane prepolymer; Add an alkyl acrylate monomer, an emulsifier, a vinyl chloride monomer, and an initiator to the first modified cationic polyurethane prepolymer and react to obtain a second modified cationic polyurethane prepolymer; Add a neutralizing agent to the second modified cationic polyurethane prepolymer to adjust it to acidic, and then through shear emulsification and solvent removal, obtain a modified cationic aqueous polyurethane dispersion; Among them, by mass percentage, the dosages of each component are as follows: the polymer polyol is 10%-35%, the diisocyanate is 8%-24%, the cationic chain extender is 1.5%-8%, the hydroxyacrylate monomer is 2%-10%, the alkyl acrylate monomer is 18%-40%, the emulsifier is 2%-10%, the vinyl chloride monomer is 3%-12%, and the neutralizing agent is 3%-9.2%; In the step of adding an alkyl acrylate monomer, an emulsifier, a vinyl chloride monomer, and an initiator to the first modified cationic polyurethane prepolymer and reacting, first add the alkyl acrylate monomer to carry out free polymerization with the first modified cationic polyurethane prepolymer, and then add the vinyl chloride monomer to continue the reaction. Among them, the alkyl acrylate monomer is selected from one or more of hexadecyl acrylate, octadecyl acrylate, and docosyl acrylate.

2. The preparation method of the modified cationic aqueous polyurethane dispersion according to claim 1, characterized in that, The hydroxyacrylate monomer is selected from one or more of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, and hydroxybutyl acrylate; And / or, the emulsifier is selected from cationic emulsifiers, and the cationic emulsifier is selected from one or more of dodecyl trimethyl ammonium chloride, cetyl trimethyl ammonium chloride, or octadecyl trimethyl ammonium chloride.

3. The preparation method of the modified cationic aqueous polyurethane dispersion according to claim 1, characterized in that, Add a neutralizing agent to the second modified cationic polyurethane prepolymer to adjust the pH to 3-6; And / or, the neutralizing agent is selected from one of glacial acetic acid, citric acid, or acetic anhydride.

4. The preparation method of the modified cationic aqueous polyurethane dispersion according to claim 1, characterized in that, In the step of performing dehydration treatment on the polymer polyol, the temperature is 110°C - 130°C, and the time is 1h - 2h.

5. The preparation method of the modified cationic aqueous polyurethane dispersion according to claim 1, characterized in that, In the prepolymerization reaction of adding a solvent, a diisocyanate, and a catalyst to the dehydrated polymer polyol, first cool the dehydrated polymer polyol to 55°C - 65°C. During the prepolymerization reaction, the prepolymerization reaction temperature is 55°C - 65°C, and the prepolymerization reaction time is 3h - 4h. During the chain extension reaction, the chain extension reaction temperature is 55°C - 60°C, and the chain extension reaction time is 0.5h - 1h.

6. The preparation method of the modified cationic aqueous polyurethane dispersion according to claim 1, characterized in that, The diisocyanate is selected from one or more of toluene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, and tetramethylxylylene diisocyanate; And / or, the cationic chain extender is selected from diethanolamine or N-methyldiethanolamine; And / or, the polymer polyol is selected from one of polyester diol, polyether polyol or polycarbonate diol.

7. A modified cationic aqueous polyurethane dispersion, characterized in that, The modified cationic aqueous polyurethane dispersion is prepared by the preparation method of the modified cationic aqueous polyurethane dispersion according to any one of claims 1-6.

8. Application of a modified cationic aqueous polyurethane dispersion as described in claim 7 as a water repellent in textiles.

Images