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• Time of issue:2020-09-03 08:59
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(Summary description)Reasonable selection of printing and dyeing auxiliaries to help improve the quality of printed and dyeing products, then how to choose printing and dyeing auxiliaries and precautions for use in reproduction must be understood. The following are the precautions for the use of printing and dyeing auxiliaries:

1. The technician must master the basic knowledge of additives: This is the prerequisite for choosing a good printing and dyeing auxiliaries. To use auxiliaries well, you must have a basic understanding of the basic concepts, basic structure, performance, and use characteristics of printing and dyeing auxiliaries. If abnormal conditions are found, the cause can also be analyzed and dealt with in time. For this reason, I wrote an overview section before each chapter in my handbook, describing the principle of action, basic characteristics, structure classification, use methods, application detection methods and points of attention when using this type of additives, so that readers can basically master this type of additives. The knowledge of additives lays a good foundation for correct use. The basic structure, properties (factory standard), usage, and usage methods of each additive will be introduced in the following introduction. If the structure type is the same, its usage and performance It's also roughly the same, and you can draw inferences about it.

If the species is not collected in the manual, as long as you know the basic structure, you can also know it well. Therefore, when Hongqi Factory uses new printing and dyeing auxiliaries, the supplier must inform the structural category of the auxiliaries. For example, the softeners used are amino silicone oil softeners, hydroxy silicone oil softeners, and fatty amide softeners. Which of the imidazoline softeners and fatty acid paraffin softeners should be known by the application plant. Only in this way can we master its basic performance and prevent blind use.

2. Basic understanding of the solubility of additives and their stability to hard water and metal ions. For example, the solubility of anionic surfactants in alkaline is greater than that in acid, while cationic surfactants are on the contrary, amphoteric surface active The agent has both anionic and cationic characteristics, while non-ionic surfactants have little effect. The solubility of the first three surfactants increases when the temperature rises, while the solubility of non-ionic surfactants decreases with the rise of temperature, so If there is a cloud point, the cloud point must be higher than the operating temperature, otherwise it will lose its efficiency and fail to play the role of additives. The cloud point increases with the increase of EO number, and increases with the amount of anionic additives incorporated, but decreases with the increase of electrolyte content. If the leveling agent is used for high temperature and high pressure dyeing as a leveling agent or dispersant, Because the use temperature greatly exceeds its cloud point (usually about 75~C), it will cause precipitation in the dyeing solution, not only does not work, but on the contrary, it will condense the dye and cause the color point.

Silicone defoamers are emulsions emulsified by methyl silicone oil or ethyl silicone oil with non-ionic surfactants and white carbon black. If emulsifiers with a low cloud point are used, the same problems mentioned above will occur. This problem is often not paid attention to, which causes great harm to printing and dyeing factories.