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水性聚氨酯胶黏剂制备工艺

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2018/10/30 浏览次数：

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随着国家生活水平的提高，近些年对环保的严格重视，环保型胶粘剂的研发日益受重视。环保型胶粘剂除了要求对材料的粘接具有牢固性、持久性和柔软性之外，还必须要具环保性，并对不同材质具兼容性，以确保成品的质量。
With the improvement of the living standard of the country, strict attention has been paid to environmental protection in recent years. In addition to requiring firmness, durability and softness, the environment-friendly adhesives must also be environmentally friendly and compatible with different materials, so as to ensure the quality of finished products.
水性聚氨酯胶粘剂与无溶剂型聚氨酯胶粘剂为环保型胶粘剂最主要的两种类型，此外，环保型胶粘剂还包括乳状/分散胶粘剂、反应型胶粘剂以及天然聚合体胶粘剂等类型。
Waterborne polyurethane adhesives and solventless polyurethane adhesives are two main types of environment-friendly adhesives. In addition, environment-friendly adhesives also include emulsion / dispersion adhesive, reactive adhesives and natural polymer adhesives.
无溶剂型聚氨酯胶粘剂一般称作热熔型聚氨酯胶粘剂，其100%由热塑性树脂组成，不含任何水分或溶剂，在熔融状态下可以流动，并在冷却后具有粘结性能，可方便用于自动化生产过程，生产效率高，而且不产生任何环境污染，不对人类造成毒害。
Solvent free polyurethane adhesive is generally called hot-melt polyurethane adhesive, the 100% is made of a thermoplastic resin composition, does not contain any water or solvent, can flow in the molten state, and has the bonding properties after cooling, it can be easily used in the production process automation, high production efficiency, and no environmental pollution, human right harm.
由于普通接触型热熔胶对被粘材质表面浸润性差，已被证实不能普遍适用于外底的粘合，因此，人们开始对反应型热熔胶粘剂进行开发研究，经过近几年的努力，现在已开发出低黏度且在适宜温度条件下能够应用的产品。反应型热熔胶借助水份或热作用进行交联，从而达到较好的粘合强度。使用无溶剂反应型聚氨酯热熔胶要配套专门涂胶设备，且操作工艺条件较严格，因此，推广应用有一定的难度。
Because of the common contact type hot melt adhesive for sticking material surface wettability is poor, has been confirmed not adhesive, generally applicable to the outsole so people started the research and development of reactive hot melt adhesive, after several years of efforts, now has developed a low viscosity and can be applied at suitable temperature conditions product. Reactive hot melt adhesive is crosslinked with water or heat, so as to achieve better bonding strength. The use of solventless reactive polyurethane hot melt adhesive must be equipped with special coating equipment, and the operation conditions are strict. Therefore, it is difficult to popularize the application.
水性聚氨酯胶粘剂不含异氰酸酯基团，而含有羧基、羟基等基团，在适宜条件下，例如在水性异氰酸酯存在时，可使胶粘剂的分子产生交联反应。大多数水性聚氨酯胶粘剂是靠分子内极性基团产生的内聚力和粘附力进行固化的。水性聚氨酯具有极性基团，如氨酯键、脲键以及离子键等，因此，对许多合成材料，尤其是极性材料、多孔性材料均具有良好的粘接性。
Waterborne polyurethane adhesives do not contain isocyanate groups, but contain carboxyl and hydroxyl groups. Under suitable conditions, for example, when waterborne isocyanates exist, crosslinking reaction of adhesives can be made. Most of the waterborne polyurethane adhesives are cured by the cohesive force and adhesion force produced by the intramolecular polar groups. Waterborne polyurethane has polar groups, such as urethane bonds, urea bonds and ionic bonds. Therefore, it has good adhesion to many synthetic materials, especially polar materials and porous materials.
与溶剂型聚氨酯胶粘剂相比，水性聚氨酯胶粘剂没有溶剂刺鼻味、无毒、无污染，且具有操作方便、残胶易清理、固体含量高以及贮运安全方便等优点，但水性聚氨酯胶粘剂的干燥时间较慢，干燥温度较高，且干燥工艺条件的要求也极为严格，以保证水份能够挥发彻底。水性聚氨酯胶粘剂对基材的润湿能力差，且胶粘剂中的水溶性高分子增稠剂会使其耐水性降低，此外，目前尚未开发出配套使用的水性表面处理剂（处于实验室研究阶段），仍需使用溶剂型表面处理剂，因此，即使使用水性聚氨酯胶粘剂，目前仍不能做到完全根除有机溶剂。
Compared with the solvent based polyurethane adhesive, waterborne polyurethane adhesive without solvent odor, non-toxic, no pollution, and has the advantages of convenient operation, easy cleaning, solid residue and high content of safe storage and transportation is convenient, but the longer drying time of waterborne polyurethane adhesive, high temperature drying, drying conditions and requirements are very strict in order to ensure the water can volatilize completely. The wetting ability of waterborne polyurethane adhesive to the substrate, and the adhesive of water soluble polymer thickener will make its water resistance is reduced, in addition, has not yet developed a water surface treatment agent for supporting the use of (at the stage of laboratory research), still need to use solvent surface treatment agent, therefore, even if the use of water polyurethane adhesive, still do not completely eradicate the organic solvent.
水性聚氨酯胶粘剂的研究始于20世纪50年代，真正受到人们所重视则是在60—70年代，但当时的水性聚氨酯胶粘剂粘合强度不高，多用于包装用胶及一些低粘合强度的场合。70年代中期开始出现用于粘合鞋底的水性聚氨酯胶粘剂，因性能欠佳，再加上环保法规不严格，到80年代末，基本上仍处于试验阶段。90年代初，欧美各国环保法规日趋严厉，对鞋厂的VOC量开始控制，水性聚氨酯分散体合成和应用工艺的研究力度得到了加强，水性聚氨酯胶粘剂的性能上基本上可以满足制鞋的要求。
The research of waterborne polyurethane adhesives began in 1950s. The real attention was from 60 to 70s, but the adhesive strength of waterborne polyurethane adhesives was not high at that time, and it was mostly used for packaging adhesives and some occasions with low adhesion strength. In the middle of 70s, waterborne polyurethane adhesives for soles were developed. Due to poor performance and environmental regulations, they were still at the experimental stage by the end of 80s. In the early 90s, the environmental regulations in Europe and the United States became more and more severe. The quantity of VOC in shoe factories began to control. The research and application of waterborne polyurethane dispersions were strengthened. The performance of waterborne polyurethane adhesives basically met the requirements of shoemaking.
介绍了这么多，水性聚氨酯胶粘剂的制备方法都有哪些呢？接下来就一起来简单了解一下吧！

What are the preparation methods of waterborne polyurethane adhesives? Let's just get to know it.

水性聚氨酯胶粘剂的制备方法分为外乳化法和自乳化法。比较而言，外乳化法制备的乳液中，由于亲水性小分子乳化剂的残留，使得固化后聚氨酯胶膜的性能收到一定的影响，而采用自乳化法则可以消除此弊病，因此，水性聚氨酯的制备目前以离子型自乳化法为主。
The preparation methods of waterborne polyurethane adhesives are divided into external emulsification and self emulsification. In comparison, the emulsion prepared by emulsion, due to residual hydrophilic small molecular emulsifier, the properties of cured polyurethane film received certain effect, but the self emulsifying law can eliminate this drawback, therefore, the preparation of waterborne polyurethane with the ionic self emulsification method.
自乳化法，主要分为预聚体法、丙酮法及熔融分散法三种。
The self emulsifying method is mainly divided into three kinds: prepolymer method, acetone method and melt dispersing method.
一、预聚体法
Prepolymer method
预聚体法即在预聚体中导人亲水成分，从而得到一定粘度范围的预聚体，在水中发生乳化的同时进行链增长，最终制得稳定的水性聚氨酯胶粘剂（水性聚氨酯—脲）。恒天的专家提醒，此法仅适用于脂肪族或脂环族聚氨酯水分散体的合成，而价格低且性能优良的芳香族端异氰酸酯预聚体与水的反应则较快，因此在水中胺扩链的效果较差。
The prepolymer method that dimer active hydrophilic component in the pre, to obtain a certain viscosity range of prepolymer in water emulsion and waterborne polyurethane adhesive chain growth, eventually obtained stable (aqueous polyurethane urea). Experts from hengtian chemical industry remind that this method is only suitable for the synthesis of aliphatic or alicyclic polyurethane aqueous dispersions, while the aromatic isocyanate prepolymer with low price and excellent performance is faster than water, so the effect of amine chain extension in water is poor.
二、丙酮法
Two, acetone method
丙酮法属于溶液法，是以有机溶剂稀释或溶解聚氨酯（或预聚体），再进行乳化的方法。在溶剂存在的情况下，预聚体与亲水性扩链剂进行扩链反应，生成分子量较高的聚氨酯，反应过程中可根据需要加人适量溶剂以降低聚氨酯溶液的粘度，使之易于搅拌，之后加水进行分散，使之形成乳液，最后蒸去溶剂。溶剂以丙酮、甲乙酮居多，故称为丙酮法。
Acetone method is a solution method, which is an organic solvent to dilute or dissolve polyurethane (or prepolymer) and then emulsify. In the presence of a solvent, prepolymer chain reaction and hydrophilic chain extender, polyurethane forming high molecular weight, the reaction process can be adding solvent to reduce the viscosity of polyurethane solution, making it easy to stir after water were dispersed to form emulsion, finally evaporating solvent. The solvent is acetone and methyl ethyl ketone, so it is called acetone method.
丙酮法和预聚体法的主要区别是，在丙酮法中，聚氨酯先预聚成分子量较大的预聚体，但由于分子量越大的预聚体粘度也越大，因此必须加入适量溶剂进行稀释以降
The main difference between acetone method and prepolymer method is that polyurethane can be prepolymerized into a larger molecular weight prepolymer in acetone process. However, because the viscosity of prepolymer with larger molecular weight is bigger, it is necessary to add appropriate solvent to dilute it.

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