Method for synthesizing water-dispersion organosilicon-polyurethane block copolymer

A block copolymer, silicone technology, applied in polyurea/polyurethane coatings, devices for coating liquid on surfaces, coatings, etc., can solve the problem of low reactivity, poor hydrolysis resistance, and low molecular weight of silane coupling agents problem, to achieve the effect of broad application prospects, good stability and simple process

Inactive Publication Date: 2008-07-23
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

For example, the physical blending method of hydroxyl silicone oil emulsion and water-based polyurethane emulsion is used, but because of the poor compatibility of hydroxyl silicone oil and polyurethane, silicone is easy to migrate to the surface and cause phase separation, so the effect is not ideal; some chemical methods are modified. Hydroxyl-terminated polysiloxane and polyol react with isocyanate together, and some use hydroxyl-terminated siloxane as chain extender to react with isocyanate group in prepolymer
However, due to the low reactivity of silanol (HO-Si) and the poor hydrolysis resistance of the Si-O-C groups generated by the reaction, the obtained organosi

Method used

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  • Method for synthesizing water-dispersion organosilicon-polyurethane block copolymer
  • Method for synthesizing water-dispersion organosilicon-polyurethane block copolymer
  • Method for synthesizing water-dispersion organosilicon-polyurethane block copolymer

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] Synthesis of prepolymers:

[0031] Add toluene diisocyanate, polyoxypropylene ether diol (hydroxyl value = 105 to 117), castor oil, dimethylol propionic acid and a small amount of solvent in sequence according to the proportion given in Table 2. In a four-neck flask with a thermometer, a thermometer, and a nitrogen pipe, react at 60-70°C for about 3 hours, and when the free NCO reaches a predetermined value, lower the temperature to stop the reaction, and the isocyanate-terminated polyurethane prepolymer is obtained. The preparation of the prepolymer can also be prepared by a stepwise reaction, that is, TDI and N 210 , Castor oil reacted for about 3 hours under the above conditions, and then reacted with DMPA to obtain a water-dispersible anionic polyurethane prepolymer

[0032] Table 2. Raw material ratio for preparing water-dispersed silicone-modified polyurethane with different chain extenders (unit: mmol)

[0033] raw material

HDA

602

NS840 ...

Embodiment 2

[0051] Embodiment 2. reaction conditions and raw material proportioning are the same as embodiment 1. The effect of castor oil and its content on the water resistance of water-dispersed silicone-polyurethane block copolymer film-formers was investigated by changing the feed ratio of polyoxypropylene ether glycol and castor oil.

[0052] Table 7. Effect of castor oil content on the water resistance of water-dispersed silicone block polyurethane film-formers

[0053] Castor Oil and N 210

[0054] Note: The carboxyl content in the copolymer = 2.0%; the number average molecular weight of the chain extender NS is 1090; when castor oil and N 210 When the molar ratio of the castor oil is 0-0.16, the water absorption decreases with the prolongation of the soaking time, which is caused by the low content of castor oil, poor water resistance, and the loss of weight in the sample.

Embodiment 3

[0055] Example 3. Effect of block density and block length on the film performance of silicone-polyurethane block copolymer emulsion

[0056] The synthesis process is the same as in Example 1. The molar ratio of castor oil to polyoxypropylene ether glycol is 0.25, and the carboxyl content of the copolymer is 2.0%, and the molecular chain length and block density of the aminoalkyl polysiloxane oligomer of the chain extender are changed to investigate its dispersion in water. Effect of silicone-polyurethane block copolymer film formers on water resistance and mechanical properties. The ratio of raw materials is shown in Table 8 and Table 9.

[0057] Table 8. Raw material ratio of water-dispersed silicone-polyurethane block copolymers with different silicone block contents (unit: mmol)

[0058]

[0059] Note: The molecular weight of aminoalkylsiloxane oligomer NS is 1090

[0060] Table 9. Raw material ratio of silicone-polyurethane block copolymer emulsions with different s...

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Abstract

The invention discloses a synthesis method for waterborne organocilicon-polyurethane block copolymer, comprising steps as follows: reaction is carried out between polyisocyanate and polyol (the polyol comprises the one from the castor oil and carboxyl polyol) to generate isocyanate-terminated polyurethane prepolymer; then chain extension is carried out via amino alkyl polysiloxane; eventually alkaline aqueous solution is adopted for neutralization and dispersion, to prepare aqueous dispersion with excellent dispersion and stability. In addition, the aqueous dispersion is applied as coating for the wood and paper, as finishing agent for leathers and textiles, or as adhesives. Since natural vegetable oil from castor beans is selected and amino alkyl polysiloxane is adopted as the chain extender. The synthesis method for waterborne organocilicon-polyurethane block copolymer has the advantages of remarkably improved hydrophobic property, heat resistance and surface smoothness for the polymer films, simple preparation technique, and easy operation.

Description

technical field [0001] The invention relates to a synthesis method and application of a water-dispersed organosilicon-polyurethane block copolymer Background technique [0002] One-component self-emulsifying waterborne polyurethane has the advantages of good stability of aqueous dispersion, non-toxicity, environmental friendliness, good adhesion, good wear resistance, good low temperature flexibility and high mechanical strength. However, due to the presence of self-emulsifying groups such as carboxyl, amino, and oxyethylene ether groups in the polyurethane molecular chain, its water resistance is poor. Therefore, how to improve its water resistance has become an urgent problem to be solved. The methods currently used are: one-component mainly uses blocked polyurethane to heat and deblock to free isocyanate groups and react with hydrophilic carboxyl groups, amino groups, urea groups, carbamate groups, etc., so that hydrophilic carboxyl groups, amino groups, etc. become hydr...

Claims

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Application Information

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IPC IPC(8): C08G18/28C08G18/61C08G18/12C08G77/458C09D175/04C09D183/10D06M15/643B05D7/12D21H21/14
Inventor 郑强林薇薇高传花华继军倪加旎陈世龙马廷方
Owner ZHEJIANG UNIV
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