Alcohol-soluble adhesive application technology

The rapid development of society has led people to pay more and more attention to their own living environment and improve their own quality of life. This requires the production enterprises in the society to create a non-hazardous working environment for their employees while producing environmentally friendly products. product. Currently, many raw materials used by plastic flexible packaging companies are toxic substances, including solvents, inks, and adhesives. The produced packaging composite film may infiltrate into the contents through the film because it contains a certain amount of toxic substances, which has potential harm to consumers.
In recent years, many non-toxic or low-toxic raw materials have been developed in the plastic flexible packaging industry, such as alcohol-soluble inks and adhesives, water-soluble ink adhesives, and solvent-free adhesives. Among them, the alcohol-soluble adhesives have attracted increasing attention from the industry due to their excellent performance, easy handling, and excellent performance-cost ratio, and they have been accepted by more and more customers. The following is a brief discussion of their own views on their application technology, for the industry insiders, welcome criticism.
Characteristics of Alcohol-soluble Adhesives 1. Alcohol-soluble adhesives contain no -NCO groups and highly toxic aromatics such as free TDI and MDI in the main agent and curing agent, compared with the currently widely used ester-soluble adhesives. Isocyanate molecules, so there is no possibility of hydrolysis to generate carcinogenic aromatic amines, so in the production of composite membranes and the future use of the product are non-toxic harmless, will not contaminate the contents of the package.
2. The alcohol-soluble binder uses industrial ethanol as the solvent, which has low pollution to the working environment of the workshop and lower production costs. The solvent used for the ester-soluble binder is ethyl acetate, which is a toxic solvent. The human eye and liver are very irritating and harm human health.
3, alcohol-soluble adhesives for plastic flexible packaging companies, the application does not require equipment transformation, does not increase the application cost, does not affect the work efficiency.
4. The alcohol-soluble binder uses industrial-grade ethanol as a solvent, is insensitive to moisture content, and can be safely produced in a humid climate without any quality accident.
5. The alcohol-soluble adhesive has good initial tack, strong operational adaptability, good transparency of the composite film, good leveling property, and avoiding the generation of white spots and air bubbles under low sizing conditions. .
6. The use of alcohol-soluble binders and alcohol-soluble inks can achieve excellent composite strength. In order to adapt to the benzene-free packaging requirements in China, alcohol-soluble inks are used by more and more manufacturers. After the alcohol-soluble type, the residual solvent will react with the hardener of the ester-soluble adhesive, which will affect the chemical reaction. The ester-soluble binder cures to reduce the composite fastness.
7. Alcohol-soluble adhesives require low maturation temperature and short curing time, which can save energy and shorten the delivery time of products.
Suitable for composite substrates Alcohol-soluble adhesives can be widely used in pre-treated PE, PP, PA, PET, PT, AL, aluminized films, paper and other substrates.
Composite Process Reference The following describes the application process and performance of the ECO series alcohol-soluble adhesives produced by the United States-owned company, Occidental Industries (Shenzhen) Co., Ltd. as an example.
1. Film structure BOPP/CPE
Adhesive type: ECO501A/B, main agent to curing agent ratio 13:1;
Application process: working concentration 25%, cable type 150 line 40μ, drying temperature 60°C, 70°C, 80°C, compound roll temperature 65°C, machine speed 120m/min, compound pressure 4kg, curing temperature 40°C, glue solution Viscosity is 14 seconds (3rd Zahn Cup).
2. Composite film structure BOPP/VMPET (full version white ink)
Adhesive type: ECO702A/B, main agent to curing agent ratio 12:1;
Application process: working concentration 30%, network cable type 120 line 55μ, drying temperature 60°C, 70°C, 80°C, composite roller temperature 60°C, machine speed 100m/min, composite pressure 4kg, curing temperature 40°C, glue solution Viscosity is 17 seconds (3# Zahn cup). Test results and performance: dry basis weight 1.45 g/m2 (see Table 1)
Test results and performance: Glue basis weight 1.97 g/sq.m., apparently good, no white spots. (See Table 2)
Operational Precautions 1. If the device was previously using an ester-soluble binder, the beater, glue tank, anilox roller, and circulation pump should be cleaned with ethyl alcohol before using the alcohol-soluble binder. Then rinse with ethanol to avoid contaminating the glue and blocking the cable roller.
2. The working concentration of alcohol-soluble binder is generally 20-35%.
3, the preparation sequence: first add the main agent, then add the solvent, stir evenly, then add the main agent, and finally stir evenly.
4, composite film curing in the aging room can speed up the curing speed, but the aging temperature should not be too high, generally controlled within 45 °C, can also be natural aging.
5, with a good glue is best used the same day, if the remaining residual liquid is too much, can be diluted several times after the dilution of the diluent, the next day of production, can be used as a diluent, each time a small number of new Used in glue, if the glue has already started to solidify or thicken, it cannot be used.
6. Other matters needing attention: The alcohol-soluble adhesive is not suitable for cooking and packaging, and can not be used for anti-media packaging. For example, the content is liquid pesticide, liquor, chili sauce and other packaging.

Table 1

Table 2