阅读说明：本技术 一种基于静电自组装的乳液纳米复合乳液及其制备方法 (Emulsion nano composite emulsion based on electrostatic self-assembly and preparation method thereof ) 是由 马建中 李文博 周永香 孙晓丹 于 2019-09-10 设计创作，主要内容包括：本发明公开了一种基于静电自组装的乳液纳米复合乳液及其制备方法,成本低廉、制备方法环保、产品稳定性好,可用于皮革复鞣。本发明的技术方案为：一种基于静电自组装的乳液纳米复合乳液的制备方法,采用一锅法制备水性聚氨酯,将水滑石分散在水中,在聚氨酯乳化阶段加入,使水滑石在聚氨酯基体中均匀分散,利用水滑石的正点性和聚氨酯的负电性使两者组装,制得基于静电自组装的乳液纳米复合乳液。本发明使用水滑石作为一种纳米材料对水性聚氨酯进行改性,其材料易制成本低廉、制备方法简单环保、产品稳定性好；制得的水滑石包覆聚氨酯纳米复合乳液可用于皮革复鞣,能够提高制革过程中的染料吸收率,降低废水污染,赋予成革一定的阻燃性能。(The invention discloses an emulsion nano composite emulsion based on electrostatic self-assembly and a preparation method thereof, which have the advantages of low cost, environment-friendly preparation method and good product stability and can be used for leather retanning. The technical scheme of the invention is as follows: a preparation method of an emulsion nano composite emulsion based on electrostatic self-assembly is characterized in that waterborne polyurethane is prepared by adopting a one-pot method, hydrotalcite is dispersed in water and added in a polyurethane emulsification stage, so that the hydrotalcite is uniformly dispersed in a polyurethane matrix, and the hydrotalcite and the polyurethane are assembled by utilizing the positive point property of the hydrotalcite and the electronegativity of the polyurethane, so that the emulsion nano composite emulsion based on electrostatic self-assembly is prepared. According to the invention, the hydrotalcite is used as a nano material to modify the waterborne polyurethane, the material is easy to prepare and low in cost, the preparation method is simple and environment-friendly, and the product stability is good; the prepared hydrotalcite-coated polyurethane nano composite emulsion can be used for leather retanning, can improve the dye absorption rate in the leather making process, reduces the wastewater pollution, and endows the finished leather with certain flame retardant property.)

1. A preparation method of an emulsion nano composite emulsion based on electrostatic self-assembly is characterized by comprising the following steps:

The method comprises the steps of preparing waterborne polyurethane by adopting a one-pot method, dispersing hydrotalcite in water, adding the hydrotalcite in a polyurethane emulsification stage to uniformly disperse the hydrotalcite in a polyurethane matrix, and assembling the hydrotalcite and the polyurethane by utilizing the positive point property of the hydrotalcite and the electronegativity of the polyurethane to prepare the emulsion nano composite emulsion based on electrostatic self-assembly.

2. The method for preparing the emulsion nanocomposite emulsion based on electrostatic self-assembly according to claim 1, wherein the method comprises the following steps:

the method comprises the following specific steps:

step one, preparing a hydrotalcite nano-sheet layer:

Firstly, 0.03 ~ 0.3.3 mol of nitrate A, 0.03 ~ 0.2.2 mol of nitrate B and 0.001 ~ 0.05.05 mol of anhydrous sodium carbonate are weighed and dissolved in 100 ~ 300mL of deionized water, the pH value is adjusted to 6 ~ 13, the mixture is stirred and reacted for 1 ~ 3h at the temperature of 70 ~ 100 ℃, then the mixture is subjected to heat preservation and crystallization for 10 ~ 18h, and after the reaction is finished, the hydrotalcite nano material is obtained through filtering, washing, drying and grinding;

Nitrate A being Mg (NO)₃)₂、Ni (NO₃)₂、Zn (NO₃)₂、Ca (NO₃)₂、Cu (NO₃)₂、Cd (NO₃)₂Or Co (NO)₃)₂；

Nitrate B being Al (NO)₃)₃、Ga (NO₃)₃、In (NO₃)₃Or Cr (NO)₃)₃；

step two, preparing the hydrotalcite-coated polyurethane nano composite emulsion:

firstly, weighing 10 ~ 20g of polyol, heating to 100 ~ 120 ℃, vacuumizing and stirring for 1 ~ 2h until complete dehydration, then reducing the temperature of the system to 50 ~ 70 ℃, adding 1 ~ 3g of 2, 2-dihydroxybutyric acid, dissolving and stirring uniformly, continuing to increase the temperature to 70 ~ 90 ℃, dropwise adding 3 ~ 9g of diisocyanate, carrying out heat preservation and polymerization for 1 ~ 5h at a stirring speed of 200 ~ 400r/min, reducing the temperature to 40 ℃ after the reaction is finished, adding 0.5-2mL of triethylamine for neutralization, adding the water dispersion of hydrotalcite in the emulsification stage of waterborne polyurethane, stirring vigorously for 1h at a rotation speed of 800-.

3. The method for preparing the emulsion nanocomposite emulsion based on electrostatic self-assembly according to claim 2, wherein the method comprises the following steps:

In the first step, a 1 ~ 3mol/L NaOH aqueous solution is used for adjusting the pH.

4. The method for preparing the emulsion nanocomposite emulsion based on electrostatic self-assembly according to claim 3, wherein the method comprises the following steps:

In the second step, the preparation method of the hydrotalcite aqueous dispersion comprises the step of dispersing hydrotalcite with the mass fraction of 0-10% in 40-100mL of water.

5. The method for preparing the emulsion nanocomposite emulsion based on electrostatic self-assembly according to claim 4, wherein the method comprises the following steps:

In the second step, the time of the emulsification reaction is 0.5 ~ 2h, the stirring speed during the emulsification reaction is 800 ~ 1400r/min, and the diisocyanate is toluene diisocyanate, diphenylmethane diisocyanate or isophorone diisocyanate.

6. a hydrotalcite coated polyurethane nanocomposite emulsion obtained by the process according to claims 1 to 5.

Technical Field

The invention belongs to the field of polymer nano composite materials, and particularly relates to an emulsion nano composite emulsion based on electrostatic self-assembly and a preparation method thereof.

Background

The water-based polyurethane is a retanning agent with excellent comprehensive performance, and because a large amount of carbamate groups similar to the chain structure (amido bonds) of the collagen peptide of the natural leather are contained in the molecular chain, the water-based polyurethane can not only keep the natural hand feeling of the leather when being used for leather retanning, but also endow the leather with excellent flexibility and dyeing property. The traditional polyurethane retanning agent has the defects of poor thermal stability, poor retanning performance, single functionality and the like. Therefore, the retanning performance of polyurethane can be improved and the functionality can be endowed by properly modifying the polyurethane retanning agent.

The organic-inorganic nano composite material combines the characteristics of organic and inorganic materials, such as thermal stability, solubility, processability and the like, and is a new generation composite material with high performance and multiple functions. The water-based polyurethane matrix can be reinforced and modified by adopting inorganic nano materials such as hydrotalcite, graphene, silicon dioxide and the like, so that the defects of the matrix material can be effectively overcome, the thermal stability of the matrix material can be improved, and the composite material can be endowed with new performances such as electric conductivity, thermal conductivity, heat insulation, flame retardance, adsorbability and the like.

Hydrotalcite is a layered metal hydroxide, and has the characteristics of enhancing the thermal stability of a substrate and endowing the substrate with adsorbability and flame retardance. The hydrotalcite has weak positive properties, and is introduced into the anionic polyurethane, and because the hydrotalcite and the anionic polyurethane have different charges, self-assembly behavior can be generated based on electrostatic acting force, so that the hydrotalcite-coated polyurethane nano composite emulsion is formed. The nano composite material is used for leather retanning, and can play a role in retanning and filling leather; meanwhile, the adsorption and the flame retardance of the hydrotalcite are utilized to improve the dye adsorption rate in the retanning process, reduce the pollution of waste water and endow the finished leather with certain flame retardant functionality.

disclosure of Invention

The invention aims to provide the electrostatic self-assembly based emulsion nano composite emulsion and the preparation method thereof, which utilize the characteristic that the hydrotalcite and the polyurethane have different electrical properties to enable the hydrotalcite and the polyurethane to be self-assembled, have the advantages of easy preparation of materials, low cost, simple and environment-friendly preparation method and good product stability, and can be used for leather retanning.

In order to achieve the aim, the invention provides a preparation method of an emulsion nano composite emulsion based on electrostatic self-assembly,

The method comprises the steps of preparing waterborne polyurethane by adopting a one-pot method, dispersing hydrotalcite in water, adding the hydrotalcite in a polyurethane emulsification stage to uniformly disperse the hydrotalcite in a polyurethane matrix, and assembling the hydrotalcite and the polyurethane by utilizing the positive point property of the hydrotalcite and the electronegativity of the polyurethane to prepare the emulsion nano composite emulsion based on electrostatic self-assembly.

The preparation method of the emulsion nano composite emulsion based on electrostatic self-assembly comprises the following specific steps:

step one, preparing a hydrotalcite nano-sheet layer:

Firstly, 0.03 ~ 0.3.3 mol of nitrate A, 0.03 ~ 0.2.2 mol of nitrate B and 0.001 ~ 0.05.05 mol of anhydrous sodium carbonate are weighed and dissolved in 100 ~ 300mL of deionized water, the pH value is adjusted to 6 ~ 13, the mixture is stirred and reacted for 1 ~ 3h at the temperature of 70 ~ 100 ℃, then the mixture is subjected to heat preservation and crystallization for 10 ~ 18h, and after the reaction is finished, the hydrotalcite nano material is obtained through filtering, washing, drying and grinding;

nitrate A being Mg (NO)₃)₂、Ni (NO₃)₂、Zn (NO₃)₂、Ca (NO₃)₂、Cu (NO₃)₂、Cd (NO₃)₂Or Co (NO)₃)₂；

Nitrate B being Al (NO)₃)₃、Ga (NO₃)₃、In (NO₃)₃Or Cr (NO)₃)₃；

Step two, preparing the hydrotalcite-coated polyurethane nano composite emulsion:

firstly, weighing 10 ~ 20g of polyol, heating to 100 ~ 120 ℃, vacuumizing and stirring for 1 ~ 2h until complete dehydration, then reducing the temperature of the system to 50 ~ 70 ℃, adding 1 ~ 3g of 2, 2-dihydroxybutyric acid, dissolving and stirring uniformly, continuing to increase the temperature to 70 ~ 90 ℃, dropwise adding 3 ~ 9g of diisocyanate, carrying out heat preservation and polymerization for 1 ~ 5h at a stirring speed of 200 ~ 400r/min, reducing the temperature to 40 ℃ after the reaction is finished, adding 0.5-2mL of triethylamine for neutralization, adding the water dispersion of hydrotalcite in the emulsification stage of waterborne polyurethane, stirring vigorously for 1h at a rotation speed of 800-.

In the second step, the preparation method of the hydrotalcite aqueous dispersion comprises the step of dispersing hydrotalcite with the mass fraction of 0wt% -10wt% in 40-100mL of water.

In the second step, the time of the emulsification reaction is 0.5 ~ 2h, the stirring speed during the emulsification reaction is 800 ~ 1400r/min, and the diisocyanate is toluene diisocyanate, diphenylmethane diisocyanate or isophorone diisocyanate.

In the first step, NaOH aqueous solution with the pH value of 1 ~ 3mol/L is used for adjusting the pH value, and the nitrate A is Mg (NO)₃)₂nitrate B is Al (NO)₃)₃。

the hydrotalcite-coated polyurethane nano composite emulsion is prepared by the preparation method.

compared with the prior art, the invention has the beneficial effects that:

1. According to the invention, the hydrotalcite is used as a nano material to modify the waterborne polyurethane, and the hydrotalcite and the polyurethane have different electrical properties, so that the hydrotalcite and the polyurethane are self-assembled to obtain the hydrotalcite-coated polyurethane nano emulsion.

2. The hydrotalcite-coated polyurethane nano composite emulsion provided by the invention can be used for leather retanning, can improve the dye absorption rate in the leather making process and reduce the wastewater pollution, and can endow the finished leather with certain flame retardant property.

Detailed Description

The present invention will be described in further detail with reference to specific examples, but the embodiments of the present invention include, but are not limited to, the scope shown in the following examples.

According to the invention, the polyurethane is modified by using hydrotalcite, and the hydrotalcite nanosheet layer is coated on the outer layer of the polyurethane to obtain the WPU @ LDH nano composite emulsion which has good organic-inorganic phase compatibility and stable emulsion.

The preparation method of the hydrotalcite-coated polyurethane nano composite emulsion comprises the following specific preparation steps:

The method comprises the following steps: preparing a hydrotalcite nano-sheet layer;

firstly, 0.03 ~ 0.3.3 mol of nitrate A, 0.03 ~ 0.2.2 mol of nitrate B and 0.001 ~ 0.05.05 mol of anhydrous sodium carbonate are weighed and dissolved in 100 ~ 300mL of deionized water, 1 ~ 3mol/L of NaOH aqueous solution is used for adjusting the pH value to 6 ~ 13, the mixture is stirred and reacted for 1 ~ 3h at the temperature of 70 ~ 100 ℃, then the mixture is subjected to heat preservation and crystallization for 10 ~ 18h, and after the reaction is finished, the hydrotalcite nano material is obtained through filtration, washing, drying and grinding;

Nitrate A being Mg (NO)₃)₂、Ni (NO₃)₂、Zn (NO₃)₂、Ca (NO₃)₂、Cu (NO₃)₂、Cd (NO₃)₂Or Co (NO)₃)₂；

nitrate B being Al (NO)₃)₃、Ga (NO₃)₃、In (NO₃)₃or Cr (NO)₃)₃；

step two: preparing hydrotalcite coated polyurethane nano composite emulsion;

firstly, weighing 10 ~ 20g of polyol, heating to 100 ~ 120 ℃, vacuumizing and stirring for 1 ~ 2h until complete dehydration, then, reducing the temperature of the system to 50 ~ 70 ℃, adding 1 ~ 3g of 2, 2-dihydroxybutyric acid, dissolving and stirring uniformly, continuing to increase the temperature to 70 ~ 90 ℃, dropwise adding 3 ~ 9g of diisocyanate, carrying out thermal polymerization for 1 ~ 5h, stirring at the speed of 200 ~ 400r/min, after the reaction is finished, reducing the temperature to 40 ℃, adding 0.5-2mL of triethylamine for neutralization, dispersing 0-10 wt% of hydrotalcite in 40-100mL of water to prepare an aqueous dispersion of the hydrotalcite, adding the aqueous dispersion of the hydrotalcite in the emulsification stage of the aqueous polyurethane, violently stirring for 1h, rotating at the speed of 800-.

In the first step, the nitrate A is Mg (NO)₃)₂Nitrate B is Al (NO)₃)₃。

in the second step, the diisocyanate is toluene diisocyanate, diphenylmethane diisocyanate or isophorone diisocyanate.