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CN-121975087-A - Water-based closed polyisocyanate curing agent and preparation method thereof

CN121975087ACN 121975087 ACN121975087 ACN 121975087ACN-121975087-A

Abstract

The invention provides a water-based closed polyisocyanate curing agent and a preparation method thereof, belonging to the technical field of high polymer materials. The aqueous closed polyisocyanate curing agent is prepared from the following raw materials, by mass, 15-30 parts of isocyanate polymer, 0.5-2.5 parts of alpha-amino acid, 0.5-2.5 parts of neutralizer, 8-15 parts of sealing agent and 55-70 parts of water. The invention prepares the aqueous polyisocyanate curing agent by taking the alpha-amino acid as a hydrophilic group, and the aqueous polyisocyanate curing agent has excellent storage stability and aqueous resin compatibility.

Inventors

  • SUN YUCHEN
  • FU HONGE
  • WEI JINHAO
  • LIU BO
  • HU XIHUA
  • FENG SIYANG
  • SHI JIANZE

Assignees

  • 沈阳化工研究院有限公司

Dates

Publication Date
20260505
Application Date
20260202

Claims (9)

  1. 1. The water-based closed polyisocyanate curing agent is characterized by being prepared from the following raw materials in parts by weight: 15-30 parts of isocyanate polymer, 0.5-2.5 parts of alpha-amino acid, 0.5-2.5 parts of neutralizer, 8-15 parts of sealing agent and 55-70 parts of water.
  2. 2. The aqueous blocked polyisocyanate curing agent of claim 1 wherein the isocyanate polymer is selected from one or both of a trimer of diisocyanate, a reactive prepolymer of diisocyanate and a polyol.
  3. 3. The aqueous blocked polyisocyanate curing agent of claim 2 wherein the trimer of diisocyanate is one or more of hexamethylene diisocyanate trimer, isophorone diisocyanate trimer and 4,4' -dicyclohexylmethane diisocyanate trimer; the diisocyanate is one or more of isophorone diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 4' -dicyclohexylmethane diisocyanate, toluene diisocyanate, 4-diphenylmethane diisocyanate and 2, 4-trimethyl-hexamethylene diisocyanate; the polyhydroxy compound is one or more of trimethylolpropane, pentaerythritol and glycerol.
  4. 4. The aqueous blocked polyisocyanate curing agent of claim 1 or 3 wherein the α -amino acid is one or more of glycine, alanine, lysine, valine, leucine, isoleucine, tyrosine, threonine and cysteine.
  5. 5. The aqueous blocked polyisocyanate curing agent of claim 4 wherein the neutralizing agent is an organic base neutralizing agent.
  6. 6. The aqueous blocked polyisocyanate curing agent of claim 1 or 5 wherein the blocking agent is one or more of 3, 5-dimethylpyrazole, butanone oxime, acetoxime, caprolactam, ethyl acetoacetate, diethyl malonate and phenol.
  7. 7. The method for preparing the aqueous blocked polyisocyanate curing agent according to any one of claims 1 to 6, comprising the steps of: 1) Mixing the isocyanate polymer with a blocking agent and then reacting to obtain a partially blocked isocyanate polymer; 2) Adding alpha-amino acid into the partially blocked isocyanate polymer obtained in the step 1), and reacting to obtain an isocyanate prepolymer containing carboxylic acid groups; 3) Adding an organic base neutralizer into the isocyanate prepolymer containing the carboxylic acid groups obtained in the step 2) at room temperature for reaction; 4) Adding water into the step 3) for emulsification to obtain the water-based closed polyisocyanate curing agent.
  8. 8. The method according to claim 7, wherein in the step 1), the reaction temperature is 50 to 70 ℃.
  9. 9. The method according to claim 7 or 8, wherein in the step 2), the reaction temperature is 20-40 ℃ and the reaction time is 20-50 min.

Description

Water-based closed polyisocyanate curing agent and preparation method thereof Technical Field The invention relates to the technical field of high polymer materials, in particular to a water-based closed polyisocyanate curing agent and a preparation method thereof. Background The ink-jet printing is a novel printing mode which is quick and convenient to operate, wherein the adhesive is used as a main constituent component, and plays a decisive role in aspects of ink-jet printing color fastness, printing hand feeling, printing color spreading property and the like. The aqueous polyurethane adhesive applied to the inkjet printing cannot completely meet the performance requirement of the inkjet printing, and some curing agents are often added to improve the performance in the use process, wherein isocyanate curing agents are most often used and react with groups on the molecular chain of the aqueous polyurethane main agent to form a crosslinked structure, so that the effect of certain performance of the inkjet printing is improved. The conventional polyisocyanate curing agent contains isocyanate groups (-NCO), is extremely easy to react with water and difficult to store, so that the conventional curing agent is prepared before the use of the two-component waterborne polyurethane, the process is complicated, partial organic solvents are often required to be added in the preparation process to reduce the viscosity, volatile Organic Compounds (VOC) are polluted, the fabric is not clean, the residual organic solvents are harmful to human health, and the conventional polyisocyanate curing agent is applied to ink-jet printing and can influence the printing smoothness, so that the nozzle is blocked. The blocked polyisocyanate curing agent is a polyisocyanate curing agent which adopts a blocking agent to protect high-activity isocyanate groups, so that the polyisocyanate curing agent can be stored in aqueous emulsion for a long time, and when the blocked polyisocyanate curing agent is used, the blocking of the isocyanate groups can be released by heating the curing agent to a certain temperature, so that the isocyanate groups undergo a curing reaction. The method can reduce the reaction of isocyanate groups and water, effectively prolong the storage time of the polyisocyanate curing agent, reduce the ink preparation process and increase the stability of the ink. In patent CN113508150, the tricell chemistry only adopts polyoxyethylene methyl ether as hydrophilic group, and the content of hydrophilic group is higher than 10% to obtain stable self-emulsifying blocked polyisocyanate, in which case the high content of hydrophilic group can reduce the rubbing color fastness, especially the wet rubbing color fastness, of the printing and dyeing ink on fabrics. Disclosure of Invention The invention aims to provide a water-based closed polyisocyanate curing agent and a preparation method thereof, which are used for solving the problem that the curing agent of the bi-component water-based polyurethane in the prior art needs to be configured on site before use. In order to achieve the above object, the present invention provides the following technical solutions: The invention provides a water-based closed polyisocyanate curing agent which is prepared from the following raw materials in parts by weight: 15-30 parts of isocyanate polymer, 0.5-2.5 parts of alpha-amino acid, 0.5-2.5 parts of neutralizer, 8-15 parts of sealing agent and 55-70 parts of water. Further, the isocyanate polymer is selected from one or two of a trimer of diisocyanate, a reactive prepolymer of diisocyanate and a polyhydroxy compound. Further, the trimer of the diisocyanate is one or more of hexamethylene diisocyanate trimer, isophorone diisocyanate trimer and 4,4' -dicyclohexylmethane diisocyanate trimer; the diisocyanate is one or more of isophorone diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 4' -dicyclohexylmethane diisocyanate, toluene diisocyanate, 4-diphenylmethane diisocyanate and 2, 4-trimethyl-hexamethylene diisocyanate; the polyhydroxy compound is one or more of trimethylolpropane, pentaerythritol and glycerol. Further, the alpha-amino acid is one or more of glycine, alanine, lysine, valine, leucine, isoleucine, tyrosine, threonine and cysteine. Further, the neutralizer is an organic base neutralizer. Further, the blocking agent is one or more of 3, 5-dimethylpyrazole, butanone oxime, acetoxime, caprolactam, ethyl acetoacetate, diethyl malonate and phenol. The invention also provides a preparation method of the water-based closed polyisocyanate curing agent, which comprises the following steps: 1) Mixing the isocyanate polymer with a blocking agent and then reacting to obtain a partially blocked isocyanate polymer; 2) Adding alpha-amino acid into the partially blocked isocyanate polymer obtained in the step 1), and reacting to obtain an isocyanate prepolymer containing carboxylic acid groups; 3) Adding an organic base ne