A kind of synthetic method of aqueous polyurethane heterogeneous chain extension

A technology of water-based polyurethane and synthesis method, applied in the direction of polyurea/polyurethane coatings, coatings, etc., can solve the problem of low allophanate content, inability to obtain high-temperature-resistant, high-hardness water-based polyurethane emulsion, small usage, etc. problems, to achieve the effect of improving the leveling performance, effectively controlling the reaction heat, and increasing the amount of use

Active Publication Date: 2020-12-15
SHANGHAI WEIKAI CHEM +1
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, this method is to use water-soluble fatty amines for chain extension after dispersion and emulsification. The prepolymer does not contain amine chain extenders, that is, the amount of fatty amines used is small, which will cause the content of allophanate in the polyurethane chain segment to increase. low, it is impossible to make water-based polyurethane emulsion with high temperature resistance and high hardness

Method used

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  • A kind of synthetic method of aqueous polyurethane heterogeneous chain extension

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Embodiment 1

[0046] The present invention relates to a kind of preparation method of the aqueous polyurethane resin of heterogeneous chain extension, comprises the following steps:

[0047] (1) Add 367 parts of adipic acid polyester diol with a number average molecular weight of 2000 to a drying reactor equipped with a stirrer, a thermometer, and a reflux condenser, raise the temperature to above 100° C., and dehydrate to obtain material a.

[0048] (2) Add 326 parts of isophorone diisocyanate, heat up to 80° C. and carry out polymerization reaction for 3 hours to obtain material b;

[0049] (3) When the mass percent content of isocyanate groups in material b reaches 15.6%, add 47 parts of dimethylolpropionic acid to material b, maintain the temperature at 75-80°C, add 26 parts of trimethylolpropane, 150 Part of acetone, insulation 3h obtains material c;

[0050] (4) When the mass percent content of isocyanate groups in the material c reaches 6.4%, add 30 parts of triethylamine and 200 pa...

Embodiment 2

[0056] The present invention relates to a kind of preparation method of the aqueous polyurethane resin of heterogeneous chain extension, comprises the following steps:

[0057] (1) Add 244 parts of adipic acid polyester polyol with a molecular weight of 2000 to a drying reaction kettle equipped with a stirrer, a thermometer and a reflux condenser, raise the temperature to above 100° C., and dehydrate to obtain material a.

[0058] (2) Add 410 parts of isophorone diisocyanate, heat up to 80° C. and carry out polymerization reaction for 3 hours to obtain material b;

[0059] (3) When the mass percent content of isocyanate in material b reaches 22%, add 69 parts of dimethylol propionic acid to material b, add 10 parts of trimethylolpropane, 400 parts of acetone, and maintain the temperature at 75-80 ℃, heat preservation for 3h to obtain material c;

[0060] (4) When the mass percent content of isocyanate groups in the material c reaches 8.5%, add 50 parts of triethylamine and 40...

Embodiment 3

[0066] The present invention relates to a kind of preparation method of the aqueous polyurethane resin of low solvent consumption, comprises the following steps:

[0067] (1) Add 123 parts of polycarbonate diol with a molecular weight of 1000 to a dry reaction kettle equipped with a stirrer, a thermometer and a reflux condenser, raise the temperature to above 100° C., and dehydrate to obtain material a.

[0068] (2) Add 170 parts of diphenylmethane diisocyanate, heat up to 70-90°C to carry out polymerization reaction for 2-4 hours to obtain material b;

[0069] (3) When the content of isocyanate groups in material b reaches 17.6% (mass ratio), add 20 parts of dimethylol butyric acid to material b, maintain the temperature at 75-80°C, and add 8 parts of trimethylolethane , 180 parts of acetone, heat preservation for 3h to obtain material c;

[0070] (4) When the isocyanate group content in material c reaches 7.0% (mass ratio), add 12 parts of N, N dimethylethanolamine and 20 p...

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Abstract

The invention provides a heterogeneous chain extension synthesis method for waterborne polyurethane. The method comprises the following steps: S1, pre-polymerizing: dehydrating polyester polyol, and performing a pre-polymerization reaction on the dehydrated polyester polyol and diisocyanate; S2, performing hydrophilic chain extension and cross-linking: adding a hydrophilic chain extender, a cross-linking agent and a diluent to a material obtained in step S1, and performing a chain extension and cross-linking reaction; S3, neutralizing and extending the chain: adding neutralizing amine, water,the diluent, a pH buffer agent and fatty amine to a material obtained in step S2, and ending the reaction to obtain a prepolymer; S4, performing dispersing emulsification: adding water to a material obtained in step S3 to achieve emulsification in order to uniformly disperse the prepolymer in water; and S5, performing a post-chain extension reaction: adding a post-chain extension amine to a material obtained in step S4, performing chain extension in water, and performing reduced pressure distillation to remove the solvent in order to obtain the waterborne polyurethane. The method uses fatty amine to carry out chain extension in a heterogeneous state in order to synthesize the waterborne polyurethane resin with high content of allophanate; and the obtained emulsion has the advantages of small micelle particle size, low viscosity, good leveling property and good storage performance.

Description

technical field [0001] The invention relates to the technical field of polymer materials, in particular to a method for synthesizing water-based polyurethane heterogeneous chain extension. Background technique [0002] Due to its good physical properties, such as elasticity, solvent resistance, and film-forming properties, waterborne polyurethane is currently widely used in various fields. In principle, it is possible to reduce the VOC content and produce low-emission coatings that are not harmful to health. But in fact, due to the use of monomers that are not suitable for dissolution during the synthesis process, high-boiling point solvents or plasticizers are widely used in the synthesis process. On the one hand, they assist in the dissolution of hydrophilic compounds and improve the reaction conversion rate of hydrophilic monomers; On the other hand, it assists in dissolving the polyurethane chain segment and improves the film-forming properties of the product. These hi...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08G18/10C08G18/42C08G18/44C08G18/66C08G18/32C08G18/34C09D175/06C09D175/04
CPCC08G18/10C08G18/4238C08G18/44C08G18/6651C08G18/6655C08G18/6659C09D175/04C09D175/06C08G18/348C08G18/3234C08G18/3228C08G18/3271
Inventor 董海普吴奎张钰馨
Owner SHANGHAI WEIKAI CHEM
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