In recent years, with the improvement of people's living standards, the requirements for the packaging of goods have become higher and higher. Corrugated cartons as commodity packaging containers must not only ensure the safety of the transportation of goods, but also have the effect of beautifying the goods, increasing the added value, and promoting sales. In particular, various kinds of beautifully printed new moisture-proof coatings appear on the market in recent years. Carton boxes, to a large extent, improve the quality of the packaging cartons, and fundamentally solve the carton packaging susceptible to moisture, easy to mold, vulnerable to problems.
The current market demand for carton boxes with waterproof performance is continuously increasing, especially in the areas of packaging for vegetables, food, household appliances and industrial products. In particular, the rapid increase in the use of water-resistant cartons for export products has greatly promoted the development of the corrugated box manufacturing industry.
Waterproof cardboard features and waterproof coating
Waterproof paperboard refers to a generic name for paperboard that has resistance to water destroying its strength. It is generally coated with a waterproof coating on corrugated board and dried. After the waterproof coating is brushed on the carton and dried quickly, the film has high transparency and good gloss, and the coating is smooth and non-adhesive, which has no effect on the carton printing ink. After the general corrugated carton has been coated with a waterproof coating, the surface of the carton can have enhanced abrasion resistance, scratch resistance, and high strength, and has strong water resistance and good moisture resistance, and can beautify and protect the carton for a long time. effect.
At present, the domestic waterproof coatings mainly include: oil-soluble, alcohol-soluble and water-soluble waterproof coatings. Compared with these three types of waterproof coatings, the water-soluble waterproof coatings have better gloss and moisture resistance than oil-soluble and alcohol-soluble waterproof coatings. Water-soluble carton waterproof coating is usually based on paraffin wax, oxidized polyethylene as the main film-forming substance, and with a dispersant, stabilizers, thickeners, brighteners, regulators, water and other additives to form a water-based emulsion .
Its outstanding advantages are: non-toxic and odorless, good resistance to water permeability, non-flammability, good stability, and good adaptability to temperature difference between hot and cold. With the use of safe, low price, excellent waterproof and moisture resistance, easy to use (spray, paint, brush can be) characteristics.
The following table shows the technical specifications of a water-soluble carton waterproof coating.
Oxidized polyethylene waterproof coating main indicators
Indicator Name Indicator
pH 7.5 - 10.5
Non-volatile content/% ≥22
Viscosity (25°C - 4 cups)/s 15～65 water
Bead Impermeability/% 100/3h
Gloss (45 degree mirror gloss) 9 to 14
Types of Waterproof Cardboards Waterproof paperboards can be broadly classified into three types depending on their water resistance:
Water-repellent corrugated cardboard - prevents the penetration of water when it is affected by water for a short time;
Water-resistant paperboard - When the water is soaked for a long time, the strength of the paperboard will not drop much;
Strong water resistant paperboard - prolonged contact with water, almost impervious to water.
(to be continued)