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A kind of cross-linked waterborne polyurethane and preparation method thereof

A water-based polyurethane and cross-linked technology, which is applied in the field of cross-linked water-based polyurethane and its preparation, can solve the problems of reduced mechanical properties of the film, difficult to control the ratio of soft and hard segments of the prepolymer, and achieves enhanced mechanical properties and water resistance. The effect of improving sexuality and enhancing hydrogen bonding

Active Publication Date: 2020-08-25
SHAANXI UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] At present, there is a method of reacting castor oil with maleic anhydride to increase the functionality of castor oil, but this technology is to first perform a monoesterification reaction of the hydroxyl group on one branched chain of castor oil with maleic anhydride, and the remaining two branched chains The hydroxyl group reacts with the isocyanate group to act as the soft segment of the polyurethane prepolymer, which makes it difficult to control the ratio of the soft and hard segment of the prepolymer, and the mechanical properties of the film are also reduced.

Method used

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  • A kind of cross-linked waterborne polyurethane and preparation method thereof
  • A kind of cross-linked waterborne polyurethane and preparation method thereof
  • A kind of cross-linked waterborne polyurethane and preparation method thereof

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preparation example Construction

[0029] A preparation method for cross-linked water-based polyurethane, comprising the following steps:

[0030] Step 1: Dissolve maleic anhydride in an organic solvent, stir to make it fully dissolved, and then slowly drop it into refined castor oil for esterification reaction. The reaction is carried out in a microwave reactor with a microwave power of 400W~600w, in which the maleic anhydride is adjusted. The molar ratio of acid anhydride and castor oil is (2.7~3):1. After the reaction, adjust the pH=7~8 with ammonia water, add a certain amount of distilled water to dilute to a concentration of 50% to prepare a multi-double bond castor oil (MACO) aqueous solution ; The reaction formula is as follows:

[0031]

[0032] Step 2: Remove water from the polyester polyol under reduced pressure at 120°C for 2 hours for later use; add polyester polyol and diisocyanate with a molar ratio of 1: (2.6 to 3.2) into the reaction vessel, and add diisocyanate dropwise 1. Catalyst dibutylt...

Embodiment 1

[0041] Step 1: Dissolve maleic anhydride in an organic solvent, stir to make it fully dissolved, and slowly add it dropwise to refined castor oil for esterification reaction. The reaction is carried out in a microwave reactor with a microwave power of 400W and 100°C for 60 minutes. Adjust the molar ratio of maleic anhydride and castor oil to 2.7:1. After the reaction, adjust the pH to 7 with ammonia water, add a certain amount of distilled water to dilute to a concentration of 50% to prepare an aqueous solution of castor oil with multiple double bonds.

[0042] Step 2: Remove water from polyester polyol PE-3020 at 120°C for 2 hours for later use; add polyester polyol PE-3020 and hexamethylene diisocyanate (HDI) with a molar ratio of 1:2.6 into a three-necked flask 0.05% catalyst dibutyltin dilaurate (DBTDL) based on the total mass of HDI and PE-3020 was added dropwise, and nitrogen gas was introduced to raise the temperature to 60°C for 3h;

[0043] Step 3: Add 4% of 2,2-dimet...

Embodiment 2

[0046] Step 1: Dissolve maleic anhydride in an organic solvent, stir to make it fully dissolved, and slowly add it dropwise to refined castor oil for esterification reaction. The reaction is carried out in a microwave reactor with a microwave power of 500W and 90°C for 50 minutes. Adjust the molar ratio of maleic anhydride and castor oil to 2.8:1. After the reaction, adjust the pH to 7 with ammonia water, and add a certain amount of distilled water to dilute to a concentration of 50% to prepare an aqueous solution of castor oil with multiple double bonds.

[0047] Step 2: Remove water from polycaprolactone polyol under reduced pressure at 120°C for 2 hours for later use; add polycaprolactone polyol and isophorone diisocyanate (IPDI) with a molar ratio of 1:2.7 into a three-necked flask, Add dropwise 0.06% of the catalyst dibutyltin dilaurate DBTDL based on the total mass of polycaprolactone polyol and isophorone diisocyanate (IPDI), and heat up to 70° C. for 2.5 hours with nitr...

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Abstract

The invention discloses a preparation method for cross-linking waterborne polyurethane. The preparation method comprises the following steps that 1, polyester polyol and diisocyanate are mixed, then acatalyst of dibutyltin dilaurate is dropwise added, nitrogen is introduced, and reaction is carried out; 2, a hydrophilic chain extender is added for reaction, then a end-capping chain extender is added for reaction, and after a neutralizer is added for reaction, water is added for dispersing so as to obtain a waterborne polyurethane emulsion; and 3, a multi-double-bond castor oil solution is added into the waterborne polyurethane emulsion, an initiator is dropwise added, reaction is carried out, and after the reaction is finished, a solvent is removed so as to obtain the cross-linking waterborne polyurethane. According to the method, the waterborne polyurethane emulsion is firstly synthesized, then free radical copolymerization reaction is carried out on multi-double-bond castor oil andthe waterborne polyurethane, the multi-double-bond castor oil is connected into a waterborne polyurethane structure so as to form the cross-linking waterborne polyurethane with a spatial network structure, and therefore the mechanical performance of the cross-linking waterborne polyurethane is improved; and the spatial density inside a polymer is increased, so that the space is shrunk, water molecules are difficult to enter, and therefore the water resistance is improved.

Description

technical field [0001] The invention belongs to the technical field of polymer materials, and in particular relates to a cross-linked water-based polyurethane and a preparation method thereof. Background technique [0002] Water-based polyurethane emulsion has the problem of slow drying due to the use of water as the medium, and also shows poor heat resistance and solvent resistance due to the introduction of hydrophilic groups such as carboxyl groups and sulfonic acid groups during synthesis and the lack of chemically cross-linked linear structures. , low tensile strength and other shortcomings, which have seriously restricted the wide application of water-based polyurethane. Therefore, in order to improve the water resistance, solvent resistance and mechanical properties of water-based polyurethane, it is necessary to carry out more in-depth cross-linking modification-chemical bonds are formed between the active groups to cross-link the polyurethane macromolecular chains t...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08G18/66C08G18/67C08G18/42C08G18/34C08G18/44
CPCC08G18/348C08G18/36C08G18/42C08G18/4238C08G18/4277C08G18/44C08G18/6659C08G18/672
Inventor 来水利高晨祝旭刘转
Owner SHAANXI UNIV OF SCI & TECH
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