Application Technology of Alcohol-soluble Adhesive on Composite Packaging

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 inks and adhesives, and solvent-free adhesives. Among them, alcohol-soluble adhesives have attracted increasing attention in the industry due to their excellent performance, easy handling, and excellent performance-cost ratio, and they have been recognized 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.

First, the characteristics of alcohol-soluble adhesives

1. The alcohol-soluble binder does not contain aromatic N-isocyanate molecules such as -NCO groups and highly toxic aromatic compounds such as free TDI and MDI in the main agent and curing agent, compared to the currently widely used ester-soluble binders. The possibility of hydrolysis to produce carcinogenic aromatic amines is therefore non-toxic and harmless in the production of composite membranes and in the future use of the product and does 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. Alcohol-soluble adhesives use industrial-grade ethanol as a solvent, are insensitive to moisture content, and can be safely produced in humid climates without quality accidents.
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. Solvent residues in alcohol-soluble inks react chemically with the hardeners of ester-soluble binders after printing. Affects the cure of ester-soluble binders and reduces 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.

Second, for composite substrates

Alcohol-soluble adhesives can be widely used on substrates such as pretreated PE, PP, PA, PET, PT, AL, aluminized films, and paper.

Third, the composite process reference

The following describes the application process and performance of the ECO series alcohol-soluble adhesives produced by U.S.-Owned Enterprise (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 40 μ, drying temperature 60°C, 70°C, 80°C, compound roll temperature 65°C, machine speed 120 m/min, compound pressure 4 kg, curing temperature 40°C, adhesive The liquid viscosity is 14 s (Zahn Cup 3).
Test results and performance: dry basis weight: 1.45 g/m2

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 55 μ, drying temperature 60°C, 70°C, 80°C, composite roller temperature 60°C, machine speed 100 m/min, composite pressure 4 kg, curing temperature 40°C, adhesive The liquid viscosity is 17.s (Zahn Cup 3). Test results and performance: Glue dry basis weight 1.97 g/m2, apparently good, no white spots.

Fourth, operation precautions

1. If the device is previously using an ester-soluble binder, the doctor blade, plastic tank, anilox roller, and circulation pump should be cleaned with ethyl acetate before using the alcohol-soluble binder. Then use ethanol. Clean it so as not to contaminate the glue and clog the roller.

2. The working concentration of alcohol-soluble binder is generally 20% to 35%.

3, the preparation sequence: first add the main agent, then add the solvent, stir evenly, then add curing 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.