Water-based adhesives for more sustainable bonding Water-based adhesives are an excellent alternative to solvent-based systems because they do not contain any volatile organic compounds (VOCs), are lighter in weight, and generally require less product to form a lasting bond. Compared to other solutions, water-based adhesive systems are environmentally friendly, have low VOC content and are more user friendly. The use of water-based adhesives does not require as many safety measures as systems containing solvents, which can increase efficiency depending on the nature of the project. In addition, the finished products bonded using water-based adhesives are user-friendly: Water-based adhesives do not pose a large health risk, nor do they release toxic or odorous fumes. Types of water-based adhesive systems The trend of adhesives is strong water based. Water-based glue systems can be roughly divided into two categories: emulsion, dispersion adhesive, solution adhesive. 01 Aqueous adhesive Solution adhesive is the most traditional form of water-based adhesive system. They use water as a carrier substance and solidify as the water evaporates. These water-based adhesives are made using natural and synthetic polymers that dissolve in water. Uses for these water-based glue systems include paper adhesives and wettable glues, such as those found in envelopes, stamps and labels. Application: roller, spray and bead Bonding: Wet bonding Examples: starch/dextrin adhesives for paper applications such as book binding, and protein/casein adhesives for the food packaging industry. 02 Water-based emulsion and dispersing adhesive Water-based adhesives are mainly used for food packaging lamination. Aqueous adhesive emulsions and dispersion systems are multiphase mixtures consisting of liquid or solid polymer phases dispersed in the water phase. These water-based adhesives can be made using a variety of polymers, including PVA (vinyl acetate polymer), PVAC (vinyl acetate copolymer) and acrylic acid, as well as synthetic elastomers such as PUR (polyurethane). Like other water-based adhesives, dispersion adhesives and emulsions can also be cleaned with water. However, after the water-based glue dries, it is no longer water-dispersed, and cleaning residues may require the use of solvents and cleaners. Construction method: spray, brush, roll or ball. Bonding: wet bonding or dry bonding (water-based contact adhesive) Examples: vinyl acetate adhesives for bonding paper, wood, and cardboard, rubber latex water-based adhesives for fabrics and wood. Polyacrylate emulsions as water-based building adhesives, laminate adhesives, pressure-sensitive water-based adhesives and water-based polyurethane adhesives as dispersions and emulsions for the packaging and footwear industries. Bonding method of water-based adhesive Another way to classify water-based adhesives is by the way they form a bond. The two groups are wet bonding and dry bonding (water-based contact adhesives). 01 Wet bo...

1. The role of acrylic resin in UV-curable inks. Due to the unsaturated nature of acrylic resin, it can undergo polymerization under the action of ultraviolet light and is widely used in the manufacture of UV-curable inks. It can also be copolymerized with other substances, such as polyethers, polyurethanes, polyesters, epoxy resins, modified epoxy resins, polycaprolactams, etc., and all these copolymers can be used as resin components for UV-curable inks. 2. The role of acrylic resin in water-based inks. Copolymers of acrylic resin with other substances are used in alkali-soluble water-based inks, and acrylic resin copolymer emulsions are used in water-dispersible water-based inks. 3. The role of acrylic resins in solvent-based inks. Most acrylic resins are soluble in solvents such as aromatic hydrocarbons and esters, and some are also soluble in alcohol solvents. They are mainly used in the production of photogravure inks and flexographic inks. Due to their transparent and colorless characteristics, they are also used to produce varnishes.

Solid acrylic resins are widely used in the formulation of water-based printing inks. Common water-based printing ink formulations are usually composed of acrylate copolymer emulsion, solid acrylic resin, pigment filler and wetting agent, defoamer, etc. Acrylate copolymer emulsion is the main bonding material, and solid acrylic resin is the pigment dispersant, also known as dispersion resin. Aqueous solid acrylic resin is also called alkali-soluble acrylic resin, the main property indicators are molecular weight (Mw) and its distribution (PDI), Acid value (Acid value) and glass transition temperature (Tg). When the glass transition temperature is higher, the resin has higher hardness, gloss and weather resistance, but can not form a continuous film. When the glass transition temperature is low, the film forming is soft and easy to adhere. The solid acrylic resin used in water-based printing ink is mostly alkali-soluble resin, because the composition contains about 30% of acrylic acid or methacrylic acid, in the case of alkali dissolution, and immediately converted into emulsifying, wetting and dispersing functions of macromolecular surfactants, for a variety of substrates with low polarity, such as PE film, PP film and aluminum plating film have good adhesion fastness. Therefore, solid acrylic resin is an important material in the preparation process of water-based ink, which is not only used in the preparation process of emulsion binder, but also in the preparation process of ink. Water-based solid acrylic resin is also an excellent pigment dispersion bonding material, it provides dispersion for a variety of difficult to disperse pigments, improve color development and film formation.

(1) The use of hydrosol Hydrosol is a polymeric dispersion of very small particles, which has the characteristics of both emulsion system and solution system, and can effectively improve water resistance (2) Reduce the amount of emulsifier Although emulsifier plays an important role in the formation of micelles in polymerization and the stability of the polymerization emulsion, it is also an important reason for the decline of water resistance and adhesion. Using special emulsifiers or reducing the amount of emulsifiers can help to improve the water resistance of the emulsion. 1. Improve the bonding strength of acrylic emulsion (1) Adhesive resin The 180° peeling strength and initial adhesion of the pressure-sensitive adhesive can be significantly improved with the addition of tackifier resin. There are two ways to join. First, blending, using this method to increase the viscosity of the resin must meet three basic requirements: A. Its molecular weight must be lower than the molecular weight of the adhesive polymer; B. The glass transition temperature of the tackifying resin must be higher than that of the polymer. C. The compatibility of the tackifier resin with the adhesive polymer to be added is better. Second, before the emulsion polymerization, the tackifying resin is dissolved in the acrylate monomer in advance, and then the emulsion polymerization can also prepare the adhesive with good comprehensive properties. (2) Select different polymerization methods If using core-shell polymerization. The core of the polymer uses a harder monomer such as styrene, acrylonitrile, methacrylate, etc., while the shell of the polymer uses a softer alkyl acrylate monomer, so that the polymer emulsion with this structure can greatly improve the cohesion strength of the adhesive.Special monomer, such as copolymerization of acrylic monomer with appropriate amount of isononyl acrylate (Tg=82℃), can further improve its comprehensive properties. In order to improve the bonding of alkane materials, vinyl benzoate, tetrahydrofurfuryl methacrylate, cyclohexyl acrylate, 2-phenoxyethyl acrylate and other monomers can be copolymerized with alkyl acrylate to improve the wettability of non-polar bonded bodies and effectively improve the bonding force.