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水性聚氨酯生产工艺及配方
2018/10/29
水性聚氨酯自从20世纪70年代在我国出现至今已有将近50年发展历史，涉及的应用领域也从当初的皮革涂饰发展到现在的几乎涵盖国民生活所有领域。在十二五期间，顺应环保、安全、低碳潮流的水性聚氨酯材料将迎来高速发展的黄金时代。
Waterborne polyurethane has been developing for nearly 50 years since its appearance in China in 1970s, and its application area has also been developed from the original leather finishing to almost all areas of national life nowadays. During 12th Five-Year, waterborne polyurethane materials, which conform to environmental protection, safety and low carbon trend, will usher in the golden age of high speed development.
水性聚氨酯区别于溶剂型聚氨酯的关键在于其以水为分散介质，因此，要制得水性聚氨酯关键是要将聚氨酯水性化，聚氨酯水性化方法主要有以下几种：
The key of waterborne polyurethane is different from solvent polyurethane, and it uses water as the dispersing medium. Therefore, the key to make waterborne polyurethane is waterborne polyurethane and polyurethane waterborne methods.
外乳化法将适当分子质量聚氨酯预聚物缓慢加入到含乳化剂的水中，形成粗粒乳液，再送入乳化器形成粒径适当的乳液，这种乳化方法关键是乳化剂的选择，此法对乳化设备的要求很高，它随着预聚体黏度的降低而分散程度提高，多数情况下可在水中进行扩链(常用二胺)，这时，建议冷却到 5 ℃左右，然后在均化器中使之分散成乳液，当然，通常乳化温度也是乳化效果的重要影响因素。
The external emulsification method appropriate molecular weight polyurethane prepolymer containing emulsifier slowly into the water, the formation of coarse emulsion, and then into the formation of emulsifier emulsion particle size appropriate, the key is the choice of emulsifier emulsification method, this method of emulsifying equipment is very high, it decreased with increasing viscosity of prepolymer and the degree of dispersion to improve, in most cases by chain extension in water (usually two, then suggest amine) cooled to about 5 DEG C, and then in a homogenizer to disperse into emulsion, of course, is usually important influence emulsification temperature emulsifying effect factors.
外乳化法工艺简单，但却存在以下缺点：
External emulsification method has the advantages of simple process, but has the following disadvantages:
(1) 在分散阶段需要强力搅拌设备，搅拌情况对分散液性能影响很大；
(1) need strong mixing equipment in the dispersed phase, stirring conditions have great influence on the dispersion properties of;
(2) 制得的分散液粒径较大，一般大于 1.0μm，且粒径分布宽，贮存稳定性差；
(2) was prepared by dispersing the larger particle size, generally more than 1 m, and the particle size distribution is wide, poor storage stability;
(3) 乳化剂的存在影响成膜后胶膜的耐水性、强韧性和粘接性等力学和其他使用性能。
(3) the presence of emulsifier film film after water resistance, strong toughness and adhesion of the mechanical and other properties.
国内水性聚氨酯乳液的制备多采用聚合物自乳化法，即在聚合物分子侧链上引入适量的亲水性基团，在一定条件下分散形成稳定乳液。此种方法的关键是如何将适当的亲水性基团引入聚氨酯分子结构，且将其良好地分散于水中。国内一般多借助含亲水基团扩链剂将亲水性基团引入硬段中。这会影响硬段的规整性而降低硬段的结晶性；国外多用一种含亲水基团的大分子活泼氢化合物，并以此为软段合成了聚氨酯乳液，这样，不会影响硬段的规整性；建议可以将芳香族多异氰酸酯和多元醇的预聚物磺化，在苯环上引入-SO3H基团，在软、硬段中同时引入离子基团制得磺酸盐型水性聚氨酯，得到的聚氨酯乳液综合性能较好。
Domestic waterborne polyurethane emulsion was synthesized by polymer self emulsification method, namely the amount of hydrophilic polymer molecules in the side chain, forming a stable emulsion dispersion under certain conditions. The key of this method is how to introduce the appropriate hydrophilic group into the polyurethane molecular structure and disperse it well in the water. In China, hydrophilic groups are introduced into hard segments by using hydrophilic group chain extenders. This will affect the regularity of the crystalline hard segments decreased with the hard segment; foreign macromolecules containing a hydrophilic group, active hydrogen compounds, and as the soft segment of polyurethane emulsion, synthetic way, will not affect the regularity of the hard segments; can be aromatic isocyanate and polyol prepolymer from sulfonation, -SO3H group introduced on the benzene ring, while the introduction of ionic groups in the soft and hard segments in the sulfonated waterborne polyurethane, polyurethane emulsion has better comprehensive performance.
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