Water-based inks are primarily composed of a uniform slurry of binders, pigments, and additives. The binder is a core component of water-based inks. It not only disperses the pigment but also plays a key role in influencing ink performance, determining adhesion, water and scrub resistance, and solvent resistance. Three common types of binders for water-based inks exist: water-soluble resins, hydrosol resins, and water-dispersible resins. These resins differ in their properties and are often combined in ink formulation. While water-soluble resins dissolve in water, they have poor water resistance. Water-based inks prepared with these resins cannot be used in environments where they come into direct contact with water, limiting their use. Therefore, water-soluble resins cannot be used as the primary binder for water-based inks. Due to their low molecular weight, small particle size, and excellent uniformity, they are primarily used to adjust the viscosity and flowability of water-based inks and to disperse pigments. Hydrosol resins are prepared by neutralizing an acidic resin with a low-molecular-weight amine to form a salt, generating hydrophilic groups. These resins, also known as alkali-soluble resins, offer rapid drying and film-forming properties. Resins in this category include shellac, urethane resins, water-based amino resins, and water-soluble acrylic resins. Water-dispersible resins, also known as emulsion resins, are water-based binders that provide good dilution, fast drying, and excellent water resistance. The low viscosity and high solids content of the emulsions allow for the formation of high-performance coatings. However, water-based inks formulated with emulsion resins suffer from poor resolubility and difficulty in cleaning. Water-based printing ink formulations typically consist of an acrylate copolymer emulsion, a solid acrylic resin, a pigment, a wetting agent, and a defoaming agent. The acrylate copolymer emulsion serves as the primary binder, while the solid acrylic resin serves as the pigment dispersant, also known as a dispersing resin. The solid acrylic resins used are mostly alkali-soluble, containing approximately 30% acrylic acid or methacrylic acid. When exposed to alkali, they dissolve and immediately convert into macromolecular surfactants with emulsifying, wetting, and dispersing properties. They exhibit excellent adhesion to a variety of low-polarity substrates, such as PE film, PP film, and aluminum-coated films. Therefore, solid acrylic resin is an important functional additive in the entire water-based ink preparation process. It is not only used in large quantities in the preparation of emulsion binders, but also in considerable amounts in the ink formulation process. Another major function of water-based solid acrylic resin is to provide dispersibility for a variety of difficult-to-disperse pigments, improving color development and film-forming properties. Therefore, in the field of water-based brush ink...

The adhesive (glue) used in self-adhesive labels is a key factor in determining label performance, directly affecting the adhesive's adhesion, durability, and application scenarios. Different glue types are suitable for different materials, environments, and applications. This article will introduce the types and characteristics of self-adhesive label glues, as well as factors to consider when selecting a glue. Common Adhesive Materials In the self-adhesive industry, hot melt adhesive, hydrosol adhesive, and solvent adhesive are three common adhesive types. Each has unique performance characteristics that can meet the needs of a variety of application scenarios. Hot Melt Adhesive Hot melt adhesive is a rubber-based adhesive with high fluidity and viscosity, making it suitable for use in low-temperature environments (-5 to -10°C). It performs better than hydrosol adhesive when the surface of the object is exposed to trace amounts of oil or water. Features: • Solvent-free, non-toxic, odorless, and environmentally friendly; • High bond strength and speed; • Suitable for labeling in low-temperature environments, but not high-temperature resistant; • Poor repositionability, overall inferior to hydrosol adhesives; • Hot melt adhesives are generally not suitable for PVC. Water-based adhesives (Water-Borne adhesives) Hydrosol adhesives are environmentally friendly, low-cost, and offer excellent initial tack, suitable for a variety of materials and environments. Although they are moisture-sensitive and cure slowly, their environmental and cost advantages make them a common adhesive for self-adhesive labels. Features: • Non-toxic and odorless, environmentally friendly; • Excellent initial tack, quickly forming a strong bond with the surface being applied; • Good temperature resistance, with some products capable of withstanding temperatures up to 150°C; • Stable adhesion, which gradually strengthens over time; • Not suitable for humid environments, and will not adhere well to surfaces with water or oil stains. Solvent Adhesives (Oil Adhesives) Solvent adhesives are based on organic solvents (such as toluene and ethyl acetate). They offer high viscosity, high temperature resistance, and chemical resistance, making them suitable for specialized industrial applications. Features: • High viscosity, less prone to overflow; • High temperature resistance, suitable for outdoor labeling; • Suitable for a variety of materials and complex environments; • Quickly and securely bonds to a variety of substrates; • Short cure time, suitable for quick application; • Water resistance, maintaining a certain degree of adhesion in humid environments. Adhesive Classification Self-adhesive label adhesives can be categorized into two main types based on their viscosity: permanent adhesives and removable adhesives. This is determined by a combination of factors, including the specific application, material requirements, and the intended use environment. Below are key comparis...

I.Characteristics of Paper-Plastic Composite Packaging Materials Paper-Plastic Composite Packaging Materials As end-consumers increasingly demand visual impact and packaging perfection from various brands, as well as a focus on environmental sustainability, many brands are incorporating more paper elements into their packaging designs. Fruit gift boxes, snack bags, and medicine boxes all feature paper-plastic composite packaging structures. The novel and unique design of paper-plastic composite packaging materials has generated strong sales for brand owners. Paper-plastic composite packaging materials are a composite material composed of a paper-based material and one or more other film materials, combined through one or more lamination processes to create a functional composite material. Paper-plastic composite materials overcome the shortcomings of plastic film's poor printability and water-induced deformation, offering high strength, excellent water resistance, and a beautiful appearance. They are currently one of the most popular packaging materials and are widely used in the food, daily chemical, and hygiene product industries. They are also widely used in beverage and food packaging, pharmaceutical packaging, high-end paper boxes, and paper bags for clothing. Materials and Equipment for Paper-Plastic Lamination The materials involved in the paper-plastic lamination process include: adhesive for laminating paper-plastic lamination, laminating machines, laminating paper, and laminating films. Laminating Adhesives: Single-component acrylic adhesives are generally used for paper-plastic lamination. Laminating Machines: Paper-plastic lamination generally falls into two categories: thin paper and film lamination, and thick paper and film lamination. The tension and roll diameter of the former are similar to those of conventional flexible packaging laminating machines, and they typically utilize dual-purpose machines for both paper-plastic and plastic-plastic lamination. The technical parameters and structure of the latter differ significantly from those of flexible packaging laminating machines, and they typically utilize dedicated laminating machines for paper-plastic lamination. Precautions for Using Paper-Based Materials for Paper-Plastic Lamination A wide variety of paper materials can be used for laminating, including coated paper, white kraft paper, yellow kraft paper, offset paper, writing paper, light-weight coated paper, pearlescent paper, soft tissue paper, and base paper. Depending on the packaging design requirements, different composite structures can be created, such as OPP/paper, PET/paper, CPP/paper, PE/paper, and AL/paper. There are dozens of different types of paper, depending on the end use and process. Commonly used in paper-plastic packaging include kraft paper, white kraft paper, soft tissue paper, base paper, and pearlescent paper, with basis weights ranging from 25g to 80g. Due to the wide variety of paper types and their ...

The performance of the ink mainly depends on the resin emulsion; for instance, the viscosity, adhesion, gloss, drying, and printing adaptability of the ink are mainly determined by the resin. Water-based inks use water-based acrylic copolymer resins, as these resins have significant advantages over alkyd resins, epoxy resins, and polyurethane resins in terms of gloss, weather resistance, heat resistance, water resistance, chemical resistance, and pollution resistance, enabling them to exhibit excellent performance whether in direct dispersion or in the synthesis of high molecular emulsions. When promoting water-based inks, due to the limitations of printing equipment and drying equipment, ink manufacturers often add a certain amount of alcohols (mainly ethanol) to the ink during formulation or printing plants during printing to increase the drying speed of the ink. This requires the resins used in the ink formula to have certain alcohol resistance. Water-based inks are prone to plate blocking during intaglio printing, significantly reducing the printing adaptability of the ink. The main factor affecting ink plate blocking is the re-dissolution (i.e., re-solubility, the ability of the ink remaining in the ink well after the ink well is filled with ink to be dissolved again) of the ink. When the re-dissolution of the ink is weak, the ink remaining in the bottom of the mesh cavity is difficult to be dissolved again by the ink in the ink well, thus easily causing plate blocking, and resulting in poor reproduction effect in the shallow mesh area. In flexographic printing, due to the fixed perimeter of the mesh roller on the equipment, the perimeter of the plate roller is variable and changes according to the product's repeated length, transferring the ink on the mesh roller to the printing surface of the plate. If the re-dissolution of the ink is good, the ink on the mesh roller can be replenished in time, and the ink transferred to the printing surface is very full, without ghosting. Conversely, when the re-dissolution of the ink is poor, the ink transferred to the printing surface varies, with strong color concentration in the areas with more ink and weak color concentration in the areas with less ink, resulting in ghosting. Therefore, the re-dissolution of the ink is an important indicator of ink quality and has a significant impact on the printing and composite quality of soft packaging composite materials. The core technology of water-based ink adhesion to films is to select appropriate water-based emulsions. The emulsion is the main film-forming resin of the ink, with fewer hydrophilic functional groups, and the ink film has good resistance, but its re-dissolution is poor. Therefore, the good re-dissolution of the emulsion-type resin is a key element in solving plate blocking and ghosting during the printing process of water-based inks. At the same time, the water resistance and wet rubbing resistance of the ink film are the key points that the ...