A kind of water-dispersible polyisocyanate polymer modified by silane condensation polymer and its preparation method and application

A polyisocyanate and polycondensate technology, applied in the field of coatings, can solve the problems of paint film failure, single unit structure, and no obvious effect on water resistance of water-based coatings, and achieve the effects of enhancing early water resistance, expanding the scope of application, and reducing quality risks.

Active Publication Date: 2022-03-08
智濡(广东)新材料有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Such coating environmental conditions determine that the effect of the paint film basically depends on the weather. Especially in the rainy season, the window period for painting construction is only within 4 hours a day. If the coating film cannot be improved rapidly in a short period of time Water resistance, it is very likely that after a heavy rain, the paint film will completely fail and need to be reworked and repainted
This is the main reason why water-based coatings cannot replace solvent-based coatings to achieve all-weather construction
Therefore, the use efficiency of water-based coatings in the outdoor construction of large machinery is extremely low, and it is difficult to achieve large-scale promotion and cannot fully utilize its environmental protection advantages
[0003] Chinese patent CN107922574A introduces a silane-modified polyisocyanate polymer containing thioallophanate obtained by the addition polymerization reaction of monomeric diisocyanate and mercapto-containing silane resin. The coating film obtained after the cross-linking reaction of the coating has excellent scratch resistance, but the curing agent is a two-functional compound, the curing rate of the paint film is slow under self-drying conditions, and the early water resistance is poor
CN109293872A has introduced a kind of anti-scratch and abrasion-resistant polyurethane special curing agent, and this technical scheme is to obtain a kind of curing agent by grafting reaction of diisocyanate prepolymer and diisocyanate monomer, although this curing agent can improve the scratch resistance of paint film Abrasiveness has obvious effect, but due to the introduction of polyether segment, the content of isocyanate in the obtained curing agent is low, which leads to an increase in the amount of curing agent in the formula, which increases the material cost of coating, and the solution is in No significant effect in improving the water resistance of waterborne coatings
[0004] CN108137986A has introduced a kind of coating composition that is made up of aqueous hydroxyl resin, superfine barium sulfate, colored pigment, low-viscosity polyisocyanate polymer and silane coupling agent, and this composition has excellent surface smoothness, film hardness, luster Stability, water resistance, and weather resistance, but the curing system obtained by combining low-viscosity polyisocyanate polymer with silane coupling agent is slow, and the early water resistance of the paint film has not been significantly improved
Although the siloxane structure in the curing agent structure has water resistance properties, the unit structure is relatively simple, and the functionality is less than or equal to 3. Therefore, the improvement effect of water resistance is not ideal in the early stage of film formation.

Method used

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  • A kind of water-dispersible polyisocyanate polymer modified by silane condensation polymer and its preparation method and application
  • A kind of water-dispersible polyisocyanate polymer modified by silane condensation polymer and its preparation method and application
  • A kind of water-dispersible polyisocyanate polymer modified by silane condensation polymer and its preparation method and application

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preparation example Construction

[0065] The preparation method of the water-dispersible polyisocyanate polymer modified by silane polycondensate of the present invention comprises the following steps:

[0066] Under the protection of inert gas, mix 200-300 parts of secondary aminosilane monomer and 400-600 parts of ethanol, heat to 45-85°C, add 40-80 parts of water dropwise under stirring conditions, and drop in 1-3h After completion, stir at 45-85°C for 6-12h, measure the water content by the Karl-Fisher method to monitor the end point of the reaction, stop the reaction when the water content of the reaction system is ≤0.5wt%, and obtain the non-hydrolyzed secondary aminosilane monomer containing color transparent liquid;

[0067] Under the protection of an inert gas, mix 600-1000 parts of the obtained colorless transparent liquid and 350-550 parts of alkoxysilane monomer, heat to 60-120 ° C, distill for 1-12 hours, and monitor the reaction by measuring the hydroxyl value through acetylation At the end poin...

Embodiment 1

[0071] Hydrolysis of secondary aminosilane monomers:

[0072]Introduce nitrogen into the reaction kettle for protection, and add 261.2g of cyclohexylaminopropyltrimethoxysilane and 500g of absolute ethanol at one time, stir evenly, heat to 70°C and keep warm; add deionized water dropwise at a constant speed under stirring conditions 54g, added dropwise within 2h; after the dropwise addition, stirred and reacted at 70°C for 8h, the sample was tested by the Karl-Fisher method to test the moisture content of 0.26wt%, and the reaction was terminated to obtain 815.2g of a colorless transparent liquid, which was sealed and stored ,stand-by.

[0073] Polycondensation of hydrolyzed secondary aminosilane monomers and alkoxysilane monomers:

[0074] Add 815.2 g of the obtained colorless transparent liquid and 416 g of tetraethoxysilane into the reaction kettle in turn, pass through nitrogen protection, gradually raise the temperature to 100 ° C under stirring conditions, and use an oil...

Embodiment 2

[0078] Hydrolysis of secondary aminosilane monomers:

[0079] Put nitrogen into the reaction kettle for protection, and add 287.2g of methylaminoethyltriethoxysilane and 550g of absolute ethanol at one time, stir well, heat to 60°C and keep it warm; add deionized water dropwise at a constant speed under stirring 58g, added dropwise within 2h; after the dropwise addition was completed, stirred and reacted at 60°C for 10h, the sample was tested by Karl Fischer method to have a moisture content of 0.32wt%, and the reaction was terminated to obtain 895.2g of a colorless transparent liquid, which was sealed and stored ,stand-by.

[0080] Polycondensation of hydrolyzed secondary aminosilane monomers and alkoxysilane monomers:

[0081] Add 895.2 g of the obtained colorless transparent liquid and 434 g of trimethoxyethoxysilane into the reaction kettle in turn, pass through nitrogen protection, gradually raise the temperature to 100 ° C under stirring conditions, and use an oil-water...

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Abstract

The invention provides a water-dispersible polyisocyanate polymer modified by silane polycondensate and its preparation method and application. The polymer has the following chemical formula: wherein, each R is independently selected from any hydrolyzable group; chemical formula Wherein n is an integer ≥ 1; a is an integer selected from 1, 2, 3, 4 and 5; R 1 , R 2 is any group that does not participate in the reaction. The invention creatively utilizes the outstanding advantages of silane polycondensate in terms of drying speed and water resistance to modify isocyanate compounds through chemical grafting, and the water-based paint prepared by using the curing agent of the invention has outstanding early water resistance.

Description

technical field [0001] The invention belongs to the technical field of coatings, and relates to a water-dispersible polyisocyanate polymer modified by a silane condensation polymer and a preparation method thereof, in particular to a polyisocyanate polymer for improving the early water resistance of water-based polyurethane coatings and a preparation method thereof and application. Background technique [0002] As a green and environmentally friendly coating, water-based polyurethane coatings are expected to be used to replace traditional solvent-based polyurethane coatings, and are widely used in the coating of construction machinery, rail transit vehicles, and large and medium-sized buses. However, since the core film-forming substance of water-based polyurethane is hydrophilic modified hydroxyl resin and water-dispersible polyisocyanate polymer, the paint film will not be fully formed under the condition of insufficient chemical crosslinking of hydroxyl resin and isocyana...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08G77/388C08G77/26C08G18/77C09D175/04
CPCC08G77/388C08G77/26C08G18/778C09D175/04
Inventor 李游夏雄辉
Owner 智濡(广东)新材料有限公司
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