With the improvement of people's awareness of environmental protection and the increasing demand for green production in the textile industry, traditional dyeing and finishing auxiliaries are gradually facing more and more stringent environmental requirements. Especially in the use of color-fixing agents, traditional aldehyde-containing color-fixing agents are restricted due to their possible harm to human body and environment. Therefore, the development of aldehyde-free, environmentally friendly new color-fixing agents has become an urgent need in the textile dyeing and finishing industry. Poly(dimethyldiallylammonium chloride) (PDADMAC), as a kind of aldehyde-free color fixing agent, has been widely used in textile dyeing and finishing. In this paper, we will discuss the role of PDADMAC in textile dyeing and finishing auxiliaries, especially its performance advantages as a non-formaldehyde color fixing agent, and how to improve the dyeing fastness of fabrics through the film-forming effect.
1. Basic Properties
Poly(dimethyl diallylammonium chloride) is a cationic polymer chemical formed by polymerization of diallylammonium chloride (DADMAC) monomer. Its molecular structure contains a large number of cationic groups, these groups give DADMAC strong adsorption capacity and flocculation.DADMAC has the following characteristics:
Strong cationicity: the cationic groups of polydimethyl diallylammonium chloride can interact strongly with the negative charges on the fabric, thus forming a stable film layer on the fabric surface.
Good film-forming property: polydimethyl diallylammonium chloride forms a uniform film layer on the fabric surface, which can effectively encapsulate the dye molecules and prevent the dye from falling off.
Good water solubility: Dimethyldiallylammonium chloride is easily soluble in water, and can quickly combine with the surface of textile fiber to form a stable color fixing effect.
Safety: Compared with traditional aldehyde-containing color fixing agent, dimethyldiallyl ammonium chloride does not contain formaldehyde, so it has higher safety.
2. The principle of action
During the dyeing process, the binding force between dye molecules and textile fibers determines the dyeing fastness. In order to improve the dyeing fastness, especially for fabrics with high requirements of washing fastness, sweat fastness and light fastness, the application of color fixing agent is crucial. Most of the traditional color fixatives are chemicals containing formaldehyde groups, which are able to form a cross-linking network on the textile surface, thus improving the dye binding power. However, the release of formaldehyde poses potential hazards to human health and the environment, especially affecting consumer health during long-term use.
Dimethyldiallylammonium chloride, as a non-formaldehyde color fixing agent, can improve dye fastness in several ways:
Film-forming effect: the cationic groups of polydimethyldiallyl ammonium chloride and the fibers on the surface of the textile produce a strong electrostatic effect, so that it can be uniformly adsorbed on the surface of the textile, forming a film. This film can effectively encapsulate the dye molecules and enhance the binding force between the dyes and the fibers, thus improving the fixation effect of the dyes and preventing the dyes from falling off during the washing process.
Enhance the interaction between dyes and fibers: the cationic group of polydimethyldiallylammonium chloride has an affinity interaction with the negative charge on the dye molecules, and this interaction can strengthen the binding force between dyes and fibers, making the dyeing effect more stable.
Improve the friction resistance of fabrics: the film layer formed by dimethyldiallylammonium chloride on the surface of fabrics can not only enhance the adhesion of dyestuffs, but also increase the friction resistance of fabrics, thus improving the durability of the dyed fabrics in the process of long-term use.
Prevent the migration of dyes: through the film-forming effect, it can effectively prevent the migration of dye molecules on the surface of fabrics, thus avoiding the shedding of dyes in the subsequent washing and wearing process, and improving the washing fastness and light fastness of fabrics.
3. Advantages in improving dyeing fastness
Improvement of washing fastness: the use of polydimethyl diallylammonium chloride can improve the washing fastness of dyed fabrics. Washing fastness is one of the important indicators of textile dyeing quality, the dye is easy to fall off in the washing process, resulting in color fading or uneven. And polydimethyl diallylammonium chloride through the formation of a thin film on the surface of the fabric, enhancing the binding force between the dye molecules and the fiber, effectively reducing the dye shedding in the washing process, maintaining the stability of the dyeing.
Improvement of sweat fastness and light fastness: the film-forming effect of poly(diallyldimethylammonium chloride) not only helps to improve the washing fastness of the fabric, but also enhances its sweat fastness and light fastness to a certain extent. Especially when exposed to sunlight for a long period of time, dyes may undergo photodegradation, leading to color fading. It enhances the bonding of dyes to fibers, allowing fabrics to maintain better color fastness to light and perspiration.
Improvement of fabric durability: polydimethyl diallylammonium chloride improves the durability of dyed fabrics by enhancing the interaction between dyes and fibers, especially under long-term use conditions such as friction, scrubbing, etc., and effectively prevents the migration and shedding of dyes.
Conclusion
As a kind of aldehyde-free color-fixing agent, poly(dimethyldiallyl ammonium chloride) has shown good performance in the application in the field of textile dyeing and finishing. It enhances the bonding force between dyestuff and fiber through film-forming effect, and improves the dyeing fastness of fabrics, especially in washing fastness, light fastness and sweat fastness. At the same time, the aldehyde-free property of poly(dimethyldiallyl ammonium chloride) meets the requirements of modern textile industry for green production and sustainable development. With the increasingly stringent environmental regulations and increasing consumer demand for green products, the application of dimethyldiallyl ammonium chloride in the textile dyeing and finishing industry is promising and is expected to be more widely promoted and applied in the future.