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CN-122011333-A - Aqueous polyurethane dispersion and preparation method and application thereof

CN122011333ACN 122011333 ACN122011333 ACN 122011333ACN-122011333-A

Abstract

The invention relates to a waterborne polyurethane dispersoid, a preparation method and application thereof, and belongs to the technical field of waterborne coatings. The aqueous polyurethane dispersion comprises the following preparation raw materials of diisocyanate A, polyisocyanate sulfonic acid modifier B, polyol C and amino functional compound E. According to the aqueous polyurethane dispersion, the sulfonic acid groups are introduced through the polyisocyanate sulfonic acid modifier B, and the proportion of the sulfonic acid groups in the polyisocyanate sulfonic acid modifier B to the solid content of the aqueous polyurethane dispersion is controlled to be 0.01-0.11mmol/g, so that the aqueous polyurethane dispersion has excellent storage stability, and the prepared aqueous two-component coating has the advantages of good water resistance and long service life.

Inventors

  • TAN XING
  • OUYANG JIE
  • ZHENG ZIJING
  • HUANG JIANJUN
  • CHEN YUFU
  • CHEN HONGBIN

Assignees

  • 广州冠志新材料科技有限公司

Dates

Publication Date
20260512
Application Date
20260415

Claims (10)

  1. 1. The aqueous polyurethane dispersion is characterized by comprising the following preparation raw materials: 1) At least one diisocyanate a; 2) At least one polyisocyanate sulfonic acid modifier B; 3) At least one polyol C; 4) At least one amino-functional compound E; Wherein: The number average molecular weight of the polyol C is 500-8000 g/mol; The polyisocyanate sulfonic acid modifier B is obtained by reacting polyisocyanate T with sulfamic acid G, the molar ratio of isocyanate groups of the polyisocyanate T to the sulfamic acid G is 2.4-4.5:1, the sulfamic acid G is at least one of 2-cyclohexylamine ethane sulfonic acid, 3-cyclohexylamine propane sulfonic acid and 4-cyclohexylamine butane sulfonic acid, and the ratio of sulfonic acid groups in the polyisocyanate sulfonic acid modifier B to solid matters of the aqueous polyurethane dispersion is 0.01-0.11mmol/G.
  2. 2. The aqueous polyurethane dispersion according to claim 1, wherein the starting materials for the preparation further comprise 5) a hydroxy-functional compound D having a number average molecular weight of 62 to 339 g/mol.
  3. 3. The aqueous polyurethane dispersion according to claim 1 or 2, wherein the diisocyanate A is at least one of hexamethylene diisocyanate, pentamethylene diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, naphthalene-1, 5-diisocyanate, xylylene diisocyanate, 4-dicyclohexylmethane diisocyanate, norbornane diisocyanate and isophorone diisocyanate.
  4. 4. The aqueous polyurethane dispersion according to claim 1 or 2, wherein the polyisocyanate T is at least one of an isocyanurate modification, an allophanate modification or a biuret modification based on hexamethylene diisocyanate and/or pentamethylene diisocyanate.
  5. 5. The aqueous polyurethane dispersion according to claim 1 or 2, wherein the polyol C has a number average molecular weight of 1000 to 4000 g/mol and is at least one of polyether polyol, polyester polyol and polycarbonate polyol.
  6. 6. The aqueous polyurethane dispersion according to claim 2, wherein the hydroxy-functional compound D is a compound having at least two hydroxyl groups, and the hydroxy-functional compound D is at least one of dimethylolpropionic acid, dimethylolbutyric acid, ethylene glycol, propylene glycol, 1, 3-propanediol, 1, 3-butanediol, 1, 4-butanediol, 1, 5-pentanediol, 3-methyl-1, 5-pentanediol, 1, 6-hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, 1, 4-cyclohexanediol, 1, 4-cyclohexanedimethanol, bisphenol A, hydrogenated bisphenol A, trimethylolpropane, trimethylolethane, pentaerythritol, sorbitol.
  7. 7. The aqueous polyurethane dispersion according to claim 1 or 2, wherein the amino-functional compound E is a compound containing at least one amino group, and the amino-functional compound E is at least one of ethylenediamine, 1, 2-propylenediamine, 1, 6-hexamethylenediamine, piperazine, 2, 5-dimethylpiperazine, isophoronediamine, 1, 2-cyclohexanediamine, 1, 3-cyclohexanediamine, 1, 4-cyclohexanediamine, 4' -dicyclohexylmethane diamine, 3' -dimethyl-4, 4' -dicyclohexylmethane diamine, 1, 4-cyclohexanediamine, hydrazine hydrate, diethylenetriamine, triethylenetetramine, hydroxyethylethylenediamine.
  8. 8. The aqueous polyurethane dispersion according to claim 1 or 2, further comprising water and an organic solvent, wherein the aqueous polyurethane dispersion has a solid content of 30 to 60% by weight and the organic solvent has a content of 0 to 10% by weight in the aqueous polyurethane dispersion.
  9. 9. A process for preparing the aqueous polyurethane dispersion according to claim 1 to 8, comprising the steps of: (1) Adding 4-20 parts by weight of diisocyanate A, 0.5-5 parts by weight of polyisocyanate sulfonic acid modifier B, 20-50 parts by weight of polyol C, 0-5 parts by weight of hydroxyl functional compound D and 0-10 parts of organic solvent into a reaction vessel, uniformly mixing, and heating to 50-90 ℃ for reaction until the detected NCO value reaches a theoretical value to obtain polyurethane prepolymer; (2) Dispersing the polyurethane prepolymer obtained in the step (1) in water, and then adding 0.2-2 parts by weight of amino-functional compound E for aqueous phase chain extension to obtain the aqueous polyurethane dispersion.
  10. 10. Use of the aqueous polyurethane dispersion according to any one of claims 1 to 8 in aqueous coatings.

Description

Aqueous polyurethane dispersion and preparation method and application thereof Technical Field The invention relates to the technical field of water-based paint, in particular to a water-based polyurethane dispersoid and a preparation method and application thereof. Background With the increasing severity of environmental protection requirements in the coating industry, solvent-based coatings are increasingly limited in application, and development of aqueous coatings of low-Volatile Organic Compounds (VOCs) has become a necessary trend in industry development. The aqueous coating taking the aqueous polyurethane dispersion as a main film forming substance stands out by virtue of the unique advantages of the aqueous coating, and the formed coating has excellent flexibility and touch feeling and also has excellent weather resistance and chemical resistance, so that the aqueous coating is widely applied to the coating field of various substrates such as textiles, leather, woodware, metal and the like and becomes an important force for promoting the green transformation of the coating industry. The hydrophilic monomers commonly used for synthesizing the aqueous polyurethane dispersoid are mainly divided into three categories of carboxylic acids, sulfonic acids and polyethers. The carboxylic acid and polyether hydrophilic monomers are mostly used for preparing an aqueous polyurethane system with the solid content of 30-45%, and if the two types of monomers are used for synthesizing a product with the high solid content of 50-60%, aqueous polyurethane dispersion with good storage stability and dispersion uniformity is difficult to obtain. In contrast, sulfonate groups have a much higher charge density than Yu Suosuan groups, and have stronger electrostatic interactions with water molecules, resulting in thicker and stable hydration layers. Based on the characteristic, only a small amount of sulfonic acid groups are introduced into polyurethane molecular chains, so that sufficient hydrophilicity can be endowed to the polymer, and stable dispersion of the system is ensured, so that the sulfonic acid hydrophilic monomer becomes a preferable material for synthesizing the aqueous polyurethane dispersion with high solid content. The sulfonate hydrophilizing agent commonly used at present is an aqueous solution of ethylenediamine ethanesulfonate, for example, trade name VESTAMIN A of Yingchuang chemical, and usually contains about 50% water. However, when the sulfonate hydrophilizing agent is used for synthesizing aqueous polyurethane dispersoid, the two key problems are that firstly, the moisture in the system can generate side reaction with isocyanate, and secondly, the chain extension reaction rate is extremely fast, and the precise regulation and control are difficult. To alleviate the above problems, a large amount of solvent (e.g., acetone) is generally added. For example, in the examples of patent CN101848952B (for example 13 and example 6 thereof), aqueous polyurethane dispersion with high solid content, which has a solid content of more than 50wt%, is synthesized by using aqueous solution of ethylenediamine ethanesulfonic acid sodium salt as a hydrophilizing agent, but a large amount of acetone is used in the synthesis process, and the obtained aqueous dispersion needs to remove acetone by vacuum, which not only reduces the production efficiency, but also significantly increases the energy consumption. In summary, the existing sulfonate aqueous polyurethane dispersion synthesis method has obvious defects, so that the novel sulfonate hydrophilizing agent is developed and applied to the synthesis of the aqueous polyurethane dispersion, and has important theoretical and practical significance. Disclosure of Invention The present invention provides an aqueous polyurethane dispersion, a method for producing the same, and an application thereof, wherein the aqueous polyurethane dispersion has a high solid content and excellent storage stability, and an aqueous coating material prepared from the aqueous polyurethane dispersion has the advantages of long pot life and good water resistance. In order to achieve the above purpose, the present invention adopts the following technical scheme: the invention provides an aqueous polyurethane dispersion, which comprises the following preparation raw materials: 1) At least one diisocyanate a; 2) At least one polyisocyanate sulfonic acid modifier B; 3) At least one polyol C; 4) At least one amino-functional compound E; Wherein: The number average molecular weight of the polyol C is 500-8000 g/mol; The polyisocyanate sulfonic acid modifier B is obtained by reacting polyisocyanate T with sulfamic acid G, the molar ratio of isocyanate groups of the polyisocyanate T to the sulfamic acid G is 2.4-4.5:1, the sulfamic acid G is at least one of 2-cyclohexylamine ethane sulfonic acid, 3-cyclohexylamine propane sulfonic acid and 4-cyclohexylamine butane sulfonic acid, and the ratio of sulf