Waterborne polyurethane emulsion, preparation and application of waterborne polyurethane emulsion in textiles

Abstract

The invention discloses preparation of soft wear-resistant strong-permeability waterborne polyurethane and application of the soft wear-resistant strong-permeability waterborne polyurethane in textiles. Aiming at the problems that most waterborne polyurethane products in the market are poor in fabric permeation effect, easy to float on the surface of the fabric, poor in adhesion to the fabric, poor in durability, poor in wear resistance, hard in hand feeling and capable of influencing the quality of the fabric product, the preparation method comprises the following steps of: using self-made polyfunctional amorphous macromolecular polyether polyol as a raw material; the soft wear-resistant strong-permeability waterborne polyurethane emulsion is prepared, the adhesiveness of resin to fabrics is successfully improved, and meanwhile, the soft hand feeling and wear resistance of the resin coating fabrics are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of waterborne polyurethane emulsion preparation, and particularly relates to a waterborne polyurethane emulsion, a preparation method thereof and an application thereof in textiles. Background Art

[0002] As a green and environmentally friendly functional polymer, waterborne polyurethane emulsion is mainly synthesized from isocyanate and small molecule chain extender in the hard segment and polyol in the soft segment. The different combinations of hard and soft segments, and the different types and contents of small molecule chain extenders give waterborne polyurethane excellent physical properties, which have a significant effect on improving the functional characteristics of textiles. In the application process, textile products are often treated with waterborne polyurethane emulsion to improve the texture and durability, such as scraping and impregnation of textiles. However, most waterborne polyurethane products on the market have poor penetration effect on fabrics, are easy to float on the surface of fabrics, have poor adhesion to textiles, poor durability and wear resistance, and feel hard, which affects the quality of textile products. At present, it is difficult to find a waterborne polyurethane product on the market that takes into account the softness and wear resistance of textile coatings and good penetration and adhesion. Summary of the invention

[0003] Aiming at the problem that current waterborne polyurethane products lack soft and wear-resistant textile coatings and have poor penetration and adhesion, the present invention is designed to provide a waterborne polyurethane emulsion, its preparation and its application in textiles.

[0004] The invention adds self-made multifunctional non-crystalline macromolecular polyether polyol in the synthesis process of the waterborne polyurethane emulsion, and has a suitable PO / EO ratio, so that the prepared waterborne polyurethane emulsion has good flexibility and soft hand feeling, and at the same time enhances the permeability. The high functionality and large molecular weight give a good cross-linking effect, so that the textile has good wear resistance.

[0005] One of the technical solutions of the present invention is to provide a method for preparing an aqueous polyurethane emulsion, comprising the following steps: (1) dehydrating 40-80 parts by weight of polyol under nitrogen protection at 100-120° C. for 2-5 h, adding 8-20 parts by weight of isocyanate, 2-6 parts by weight of hydrophilic chain extender, and 0.5-3 parts by weight of small molecule alcohol chain extender when the water content is below 500 ppm, stirring evenly, adding 0.003-0.02 parts by weight of catalyst and 1 part by weight of organic solvent, reacting at 70-95° C. for 1-3 h to obtain a polyurethane prepolymer; the polyol is a non-crystalline polyether polyol having a number average molecular weight of 2000-6000, a functionality of 3-6, and a PO / EO ratio of 20-50%; (2) cooling the prepolymer obtained in step (1) to 50-55° C., adding 20-30 parts by weight of an organic solvent to dilute it, stirring it evenly, then adding 0.5-3 parts by weight of a neutralizing agent and stirring for 1-15 minutes; (3) Add 45-55 parts by weight of deionized water for emulsification, add 0.5-3 parts by weight of a small molecule amine chain extender, and vacuum evaporation for desolventizing to obtain an aqueous polyurethane emulsion.

[0006] Further, the isocyanate includes one or more of toluene diisocyanate, isophorone diisocyanate, and p-phenylene diisocyanate; The hydrophilic chain extender includes one or more of dihydroxypropionic acid, sodium ethylenediamine ethanesulfonate, and polyoxyethylene ether; The small molecule alcohol chain extender includes one or more of neopentyl glycol, 1,4-butanediol, and 1,6-hexanediol; The small molecule amine chain extender includes one or more of diethylenetriamine, sodium ethylenediamine ethanesulfonate, and ethylenediamine; The catalyst is bismuth isooctanoate; The neutralizing agent is triethylamine; The organic solvent includes acetone.

[0007] The invention uses self-made multifunctional non-crystalline macromolecular polyether polyol in the synthesis process of waterborne polyurethane emulsion, wherein the functionality is 3-6, the PO / EO ratio is 20%-50%, the number average molecular weight is 2000-6000, and the molecular weight of the polyether polyol accounts for 60%-85% in the resin structure, so that the prepared waterborne polyurethane resin has good flexibility and soft hand feeling; the appropriate PO / EO ratio is conducive to improving the hydrophilic effect of the resin, enhancing the penetration effect of the resin and improving the adhesion to the fabric; the high functionality and large molecular weight give the resin a good cross-linking effect, enhance the toughness of the resin and have a good wear resistance.

[0008] In addition, the hard segment isocyanate mainly uses aromatic isocyanate with benzene ring and aliphatic isocyanate with cyclic structure. The higher cohesive energy and conjugation effect enhance the adhesion and wear resistance of the resin to the fabric. The hydrophilic group is mainly anionic. Appropriate addition of non-ionic hydrophilic chain extender and sulfonic acid hydrophilic chain extender helps to improve the hydrophilic effect and resin penetration ability.

[0009] The second technical solution of the present invention is to provide an aqueous polyurethane emulsion prepared by the above preparation method.

[0010] The third technical solution of the present invention is to provide an application of the above-mentioned aqueous polyurethane emulsion in textiles, and the specific steps are as follows: add a thickener and a color paste to the prepared aqueous polyurethane emulsion, stir evenly, adjust the viscosity to 400-4000mPa•S, impregnate or apply the aqueous polyurethane emulsion to the fabric treated with a coagulant, impregnate the coagulant again, put it in an oven for drying, wash off the residual coagulant with water, and dry to obtain the textile treated with aqueous polyurethane.

[0011] Furthermore, the thickener includes one or more of hydroxyethyl cellulose, hydroxymethyl cellulose, polyacrylate, and associative thickener.

[0012] Beneficial effects of the present invention: (1) The present invention uses non-crystalline macromolecular polyol as the soft segment to synthesize the waterborne polyurethane resin, and the polyol accounts for 60%-85% in the resin structure, which gives the waterborne polyurethane resin excellent flexibility and ensures the soft feel of the obtained textile coating; (2) The present invention uses self-made high molecular weight, high functionality polyols with good cross-linking effect, so that the regular and orderly crystalline hardness is evenly distributed in the soft segment, giving the waterborne polyurethane resin excellent wear resistance; (3) The present invention adjusts the appropriate ratio of polyol PO / EO to improve the hydrophilic effect of the resin, enhance the resin penetration effect and improve the adhesion to the fabric; (4) The isocyanate used in the hard segment of the present invention mainly adopts aromatic isocyanate with a benzene ring and aliphatic isocyanate with a cyclic structure. The higher cohesive energy and conjugation effect enhance the adhesion effect of the resin to the fabric. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a microscope image of Example 1.

[0014] Figure 2 This is a scanning electron microscope image of Example 1.

[0015] Figure 3 This is the microscope image of Comparative Example 1.

[0016] Figure 4 This is the scanning electron microscope image of Comparative Example 1. DETAILED DESCRIPTION

[0017] The following examples are used to further illustrate the present invention, and their purpose is to illustrate the present invention and should not be construed as limiting the scope of the present invention. Unless otherwise specified, all parts by weight and weight percentages are used below.

[0018] The raw materials used in the present invention, unless otherwise specified, are conventional commercially available products; the methods used in the present invention, unless otherwise specified, are conventional methods in the art.

[0019] The embodiments of the present invention are further described below with reference to a plurality of embodiments.

[0020] It should be clear that the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0021] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0022] The physical properties of the present invention can refer to the national standard: GB / T 1040.3-2006; the Matindal wear test method can refer to the national standard: GB / T 19089-2012; the penetration effect is detected by microscope and scanning electron microscope and visual observation.

[0023] Example 1 After dehydrating 40 parts by weight of a homemade polyol with a molecular weight of 2000, a functionality of 3 and a PO / EO ratio of 20% at 120°C, 8 parts by weight of toluene diisocyanate, 1 part by weight of polyoxyethylene ether and 1 part by weight of dihydroxypropionic acid, and 1 part by weight of 1,6-hexanediol were added, stirred evenly, 0.003 parts by weight of bismuth isooctanoate and 1 part by weight of acetone were added, and the mixture was reacted at 80°C for 3 hours. After the prepolymerization reaction was completed, the mixture was cooled to 50°C, 20 parts by weight of acetone were added, and stirred evenly. Then, 3 parts by weight of triethylamine were added, stirred for 15 minutes, neutralized, stirred for 10 minutes, 50 parts by weight of deionized water were added, and 1 part by weight of diethylenetriamine was added dropwise to extend the chain. Finally, the acetone was removed by rotary evaporation to obtain an aqueous polyurethane emulsion.

[0024] A small amount of hydroxymethyl cellulose thickener and color paste were added to the aqueous polyurethane emulsion prepared in Example 1, and the viscosity was adjusted to 400 mPa•S. The textile was treated with 10% acetic acid methanol solution, and the thickened aqueous polyurethane slurry was directly impregnated or coated on the textile. After the slurry was evenly spread and the excess slurry was shaken off, the textile was dried in an oven at 70°C to obtain the aqueous polyurethane textile.

[0025] Example 2 After dehydrating 60 parts by weight of a homemade polyol with a molecular weight of 4000, a functionality of 5 and a PO / EO ratio of 40% at 100°C, 12 parts by weight of toluene diisocyanate and 3 parts by weight of isophorone diisocyanate were added and stirred evenly, then 6 parts by weight of polyoxyethylene ether and 0.5 parts by weight of neopentyl glycol were added, and after sufficient stirring and dissolution, 0.01 parts by weight of zinc isooctanoate and 1 part by weight of acetone were added, and the mixture was reacted at 95°C for 1 hour, then the mixture was cooled to 55°C, 20 parts by weight of acetone were added and stirred evenly, 1 part by weight of triethylamine was added and neutralized and stirred for 1 minute, 55 parts by weight of deionized water were added and emulsified and stirred at high speed for 10 minutes, 0.5 parts by weight of ethylenediamine was added dropwise to extend the chain, and finally the acetone was removed by vacuum rotary evaporation to obtain an aqueous polyurethane emulsion.

[0026] A small amount of sodium polyacrylate thickener and color paste were added to the aqueous polyurethane emulsion prepared in Example 2, and the viscosity was adjusted to 3000 mPa·S. The mold with the glove core was treated with 2% calcium nitrate methanol solution, impregnated with the prepared aqueous polyurethane slurry, and the slurry was dripped and homogenized for 30 minutes. The slurry was then placed in an oven at 100° C. and dried to obtain a soft and well-adhered aqueous polyurethane impregnated textile.

[0027] Example 3 After dehydrating 80 parts by weight of homemade polyol with a molecular weight of 6000, a functionality of 6, and a PO / EO ratio of 50% at 120° C., 15 parts by weight of isophorone diisocyanate and 5 parts by weight of p-phenylene diisocyanate were added and stirred to dissolve, 4 parts by weight of polyoxyethylene ether and 0.8 parts by weight of sodium ethylenediamine ethanesulfonate were added, and 3 parts by weight of 1,4-butanediol were added and stirred after sufficient stirring to dissolve, and 0.02 parts by weight of bismuth isooctanoate and 1 part by weight of acetone were added after dissolution, and the mixture was reacted at 70° C. for 1 hour, cooled to 50° C., 30 parts by weight of acetone were added and stirred evenly, and 0.5 parts by weight of triethylamine was added and stirred for 10 minutes for neutralization, and 45 parts by weight of deionized water were added and emulsified after stirring for 10 minutes, and 3 parts by weight of sodium ethylenediamine ethanesulfonate were added dropwise to extend the chain, and finally acetone was removed by vacuum rotary evaporation to obtain an aqueous polyurethane emulsion.

[0028] A small amount of associative thickener and color paste were added to the aqueous polyurethane emulsion prepared in Example 3, and the viscosity was adjusted to 4000 mPa·S. The mold with the glove core was treated with 2% acetic acid methanol solution, impregnated with the prepared aqueous polyurethane slurry, and after dripping and homogenizing for 30 minutes, it was placed in an oven at 80°C for drying to obtain a soft and well-attached aqueous polyurethane impregnated textile.

[0029] Comparative Example 1 After dehydrating 38 parts by weight of polytetramethylene diisocyanate at 120°C, add 8 parts by weight of hexamethylene diisocyanate and react at 80°C for 2 h, cool to 60°C, add 1.2 parts by weight of dihydroxypropionic acid, heat to 75°C and react for 1.5 h, add 15 parts of acetone to dilute and stir evenly, add 1 part by weight of sodium hydroxide to neutralize for 15 min, then slowly add 55 parts by weight of deionized water for emulsification, finally add 0.8 parts by weight of ethylenediamine to extend the chain, and remove acetone by rotary evaporation to obtain an aqueous polyurethane emulsion.

[0030] A small amount of associative thickener and color paste were added to the prepared aqueous polyurethane emulsion of Comparative Example 1, and the viscosity was adjusted to 3000 mPa·S. The mold with the glove core was treated with 10% acetic acid methanol solution, impregnated with the prepared aqueous polyurethane slurry, and the slurry was dripped and homogenized for 30 minutes. The slurry was then placed in an oven at 100°C and dried to obtain the aqueous polyurethane impregnated glove coating emulsion, which had poor adhesion to the glove fiber on the surface of the glove core.

[0031] Comparative Example 2 After dehydrating 15 parts by weight of polycaprolactone diol and 18 parts by weight of polytetramethylene glycol at 120° C., 8 parts by weight of toluene diisocyanate and 4 parts by weight of isophorone diisocyanate were added and reacted at 80° C. for 2 h, the temperature was lowered by 60° C., 1 part by weight of dihydroxypropionic acid was added, 0.01 parts by weight of bismuth isooctanoate catalyst was added, the temperature was raised to 75° C. for reaction for 1.5 h, 20 parts by weight of acetone was added to dilute and stir evenly, 0.8 parts by weight of triethylamine was added to neutralize and react for 15 min, then 50 parts by weight of deionized water was slowly added for emulsification, and finally 0.8 parts by weight of diethylenetriamine was added to extend the chain, and the acetone was removed by rotary evaporation to obtain an aqueous polyurethane emulsion.

[0032] A small amount of hydroxymethyl cellulose thickener and color paste were added to the prepared aqueous polyurethane emulsion of Comparative Example 2, and the viscosity was adjusted to 400 mPa·S. The mold with the glove core was treated with 10% calcium nitrate methanol solution, impregnated with the prepared aqueous polyurethane slurry, and the glove was dried in an oven at 100°C after dripping and homogenizing for 30 minutes to obtain aqueous polyurethane impregnated gloves. It was found that the coating emulsion had poor adhesion to the glove fiber on the surface of the glove core and felt relatively hard.

[0033] In summary, the soft, wear-resistant, and highly permeable aqueous polyurethane emulsions used in Examples 1-3 have better stability than those in Comparative Examples 1-2, and Examples 1-3 have higher strength and elongation at break; the prepared impregnated coated textiles were observed using a microscope and a scanning electron microscope, as shown in FIG. Figure 1 , Figure 2 Microscope and scanning electron microscope images of Example 1, Figure 3 , Figure 4The microscope and scanning electron microscope pictures of comparative example 1 show that the example 1 has excellent permeability, while the coating of comparative example 1 floats on the fabric surface and has poor permeability; the Martindale wear resistance data show that the average wear resistance of the example is greater than 8000 revolutions, and has excellent wear resistance. Therefore, the textile coating product prepared by the aqueous polyurethane emulsion prepared by the present invention has the advantages of permeability, adhesion, softness, and wear resistance.

[0034] The above embodiments describe in detail the structure, features and effects of the present invention. The above are only preferred embodiments of the present invention. Any changes made in accordance with the concept of the present invention, or modifications to equivalent embodiments with equivalent changes, which do not exceed the scope covered by the specification, should be within the protection scope of the present invention.

Claims

1. A method for preparing an aqueous polyurethane emulsion, characterized in that: The following steps are involved: (1) dehydrating 40-80 parts by weight of polyol under nitrogen protection at 100-120° C. for 2-5 h, adding 8-20 parts by weight of isocyanate, 2-6 parts by weight of hydrophilic chain extender, and 0.5-3 parts by weight of small molecule alcohol chain extender when the water content is below 500 ppm, stirring evenly, adding 0.003-0.02 parts by weight of catalyst and 1 part by weight of organic solvent, and reacting at 70-95° C. for 1-3 h to obtain a polyurethane prepolymer; The polyol is a non-crystalline polyether polyol with a number average molecular weight of 2000-6000, a functionality of 3-6, and a PO / EO ratio of 20-50%; (2) cooling the prepolymer obtained in step (1) to 50-55° C., adding 20-30 parts by weight of an organic solvent to dilute it, stirring it evenly, then adding 0.5-3 parts by weight of a neutralizing agent and stirring for 1-15 minutes; (3) Add 45-55 parts by weight of deionized water for emulsification, add 0.5-3 parts by weight of a small molecule amine chain extender, and vacuum evaporation for desolventizing to obtain an aqueous polyurethane emulsion.

2. The preparation method according to claim 1, characterized in that: The isocyanate includes one or more of toluene diisocyanate, isophorone diisocyanate, and p-phenylene diisocyanate; The hydrophilic chain extender includes one or more of dihydroxypropionic acid, sodium ethylenediamine ethanesulfonate, and polyoxyethylene ether; The small molecule alcohol chain extender includes one or more of neopentyl glycol, 1,4-butanediol, and 1,6-hexanediol; The small molecule amine chain extender includes one or more of diethylenetriamine, sodium ethylenediamine ethanesulfonate, and ethylenediamine; The catalyst is bismuth isooctanoate; The neutralizing agent is triethylamine; The organic solvent includes acetone.

3. An aqueous polyurethane emulsion prepared by the preparation method according to claim 1, characterized in that: The molecular weight of polyols accounts for 60%-85% of the polyurethane structure.

4. Use of the aqueous polyurethane emulsion as claimed in claim 3 in textiles.

5. The use according to claim 4, characterized in that: The method comprises the following steps: adding a thickener and a color paste to the prepared water-based polyurethane emulsion, stirring evenly, adjusting the viscosity to 400-4000 mPa•S, impregnating or coating the fabric treated with the water-based polyurethane emulsion with a coagulant, impregnating the fabric with the coagulant again, drying the fabric in a 70-100°C oven, washing off the residual coagulant with water, and drying the fabric to obtain the water-based polyurethane treated textile.

6. The use according to claim 5, characterized in that: The thickener includes one or more of hydroxyethyl cellulose, hydroxymethyl cellulose, polyacrylate, and associative thickener.

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