Polyacrylates
1.Polyacrylates (PA):
Also called ac gel coating, is currently the most common and most common kind of coating, after coating can increase the feel, windproof, drape.
pa white glue coating, that is, on the surface of the fabric coated with a layer of white acrylic resin, can increase the coverage of the cloth, opaque color, and make the cloth color more bright.
pa silver glue coating, that is, on the surface of the fabric coated with a layer of silver-white glue, so that the fabric has a light-blocking, anti-radiation function, generally used for curtains, tents, clothing.
PA coating, polyacrylate fabric coating adhesive (Polyacrylate referred to as PA), also known as AC glue coating, that is, acrylic coating, is currently the most common and most common kind of coating, coated with an increase in feel, windproof, drape. Commonly used in anti-fleece, hand feel, solid color and solid sand. There are also acrylic, pony glue, that is, solvent acrylic coating, suitable for water pressure resistant coating, the price is slightly higher than AC. The initial polyacrylate coating adhesive belongs to the simple waterproof products, through decades of development, the current varieties not only waterproof and moisture permeability, flame retardant and other functions, but also low-temperature energy-saving features. Polyacrylate coating adhesive generally by the hard components (such as polyacrylate, etc.) and soft components (such as polybutyl acrylate, etc.) copolymerization. The main monomers of polyacrylate coating are acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, etc. In order to improve its waterproof performance, acrylamide and acrylonitrile can be added when necessary, and the polymerization initiator is generally used as a peroxide (e.g., potassium persulfate, etc.).
Waterproof coating finishing agent
This kind of polyacrylate coating finishing agent is mostly solvent-based at first, and its adhesion and water resistance are excellent. In order to improve the strength of the film, an external adhesive linker is often added. It is suitable for processing soft and thin fabrics, and can obtain high water repellency and water pressure resistance by using it once. However, solvent-based products contain a large number of organic solvents such as toluene, ethyl acetate, etc., the use of which is likely to cause environmental pollution or fire, and high solvent recovery costs. There are two main synthesis methods for solvent-based coating finishing agent, one is suspension polymerization, the molecular weight of the resulting product is high; the other is solution polymerization, the molecular weight of the resulting product is low.
In order to overcome the shortcomings of solvent-based products, aqueous polyacrylate coating finishing agents came into being. Water-based is divided into emulsions, non-soap emulsions and water-soluble three kinds. The molecular weight of emulsion type is 10-5 million, the particle diameter is 0.05-0.2 micron, and the solid content is generally 40-60%. Due to the emulsion polymerization method, a small amount of compound emulsifier is added during polymerization. Due to the presence of emulsifier, in the process of fusion film, a part of it is extruded to the interface between the film and the fabric, thus weakening the bonding strength with the fabric, and making the product’s water-resistant pressure to be affected to a certain extent. Water-soluble class is a special colloidal dispersion, which is introduced hydrophilic functional groups in polymer, and can be clarified in water, and the molecular weight of water-soluble class is generally around 100-200 thousand. The other part is extruded to the outer surface of the membrane, causing the astringency of the membrane surface, resulting in the unpleasant handfeel of the coated fabric. Non-soap emulsion class (also known as non-emulsion type) coating agent does not contain emulsifier, the fabric is mainly fine coating waterproof finishing. After finishing the fabric can maintain the original style, with a soft feel and high fastness, smooth feel, high mechanical properties and good waterproof effect.
Domestic has been reported to emulsion polymerization method to synthesize polyacrylate super micro emulsion, its average particle size below 50nm, the appearance of semi-transparent colloidal mucilage, select 2D resin as the external cross-linking agent, with fluorine-containing resins for post-water-repellency finishing, which can make the coated fabrics to obtain a higher value of the water pressure resistance and water-repellency. At present, the domestic products are mostly outwardly linked, and the crosslinking agent must be added when applying, which brings inconvenience to the manufacturers’ application. In recent years, some domestic water-based super microemulsion self-crosslinking polyacrylate fabric coating agent application performance research, the results show that its performance is excellent, has broad application prospects.
Waterproof and moisture permeability finishing agent
The fabrics finished by this kind of coating agent have two functions of waterproof and moisture permeability at the same time, and its waterproof and moisture permeability mechanism relies on the formation of a large number of micropores in the film. These pores are less than 2 microns, which can prevent water droplets (average diameter of 100 microns), but allow water vapor molecules (average diameter of 0.0004 microns) to pass through, so as to obtain waterproof breathability. In order to improve the polyacrylate processing fabrics air permeability, since the 1980s, Japan will contain carboxyl, hydroxyl, nitrile and other hydrophilic groups of acrylate copolymer dissolved in water can be miscible organic solvents made of coating adhesive, coated by the warm water treatment to remove the solvent and make the copolymers solidification, drying and de-watering so that copolymers in the fabrics to form a microscopic porous film. This coating adhesive to wet-coating treatment fabric ventilation and moisture permeability is good.
