3. Composite film adhesive for ordinary packaging

Ordinary packaging composite film polyurethane adhesive generally includes dried food (also called light product) packaging Glue and 70-100°C boiling-sterilized distillery packaging adhesive. Such adhesives are two-component solvent-based polyurethane adhesives. The home agent is a polyurethane or polyurethane polyol containing hydroxyl groups (called a component) modified by an aromatic isocyanate. The solids are aromatic isocyanates and trihydroxyls. Methyl propane adducts (called the B component). When used, the A component and the B component are mixed in a certain proportion, and then diluted with ethyl acetate to a certain concentration for sizing coating.

Instructions

Adhesive use method is reasonable to directly affect the quality of the composite film, each brand of adhesive has its own characteristics, must be detailed before using the Manufacturer's instructions for use. The basic methods for compounding, coating, and compounding and curing are briefly described here (for details, see Dry Composite Film Preparation Process).

(1) Glue preparation According to the adhesive product specification, determine the ratio of the A and B components (see the table). Working concentration of the adhesive used is 25% - 40%, the diluted solvent is ethyl acetate, the content of ethyl acetate is ≥99.8%, the water content is not more than 300*10-6, the content of ethanol is ≤0.02%, the content of acetic acid Less than 0.005%. When diluting, it is required to add ethyl acetate to the main agent, stir it well, add the curing agent to the diluted main agent, and stir it evenly. The generally prepared adhesive is stored in a closed container and can be used for 1-2 days without significantly affecting the quality of the composite film.

(2) The amount of glue applied (g/m2 calculated from the amount of dry glue) is one of the important factors affecting the bond strength of the composite film. The amount of glue must be determined according to the purpose of the composite film and the material of the film. The amount of glue for the compound film is shown in the table.

Assortment film structure and application Coated amount, g/m2 Flat and smooth film for general packaging
1.5-2.5 grades and poor smoothness films Multi-color printing inks Multi-coated films Polymer coated films 2.5-3.5 Containing moisture 3.5-4.0 Boiling packaging Distillation Bag (70—100°C) 3.0—3.5 Cooking Package Transparent Cooking Bag 3.5—4.0 Aluminum Foil Structure High-Temperature Cooking Bag 4.0—5.0 Aluminum Foil Container 4.0—5.0


(3) Composite and curing The adhesive coated film is dried in a drying tunnel at 50-80°C. The composite roll temperature is controlled at 50-90°C and the composite pressure is 0.25-0.4 MPa. The composite film usually needs to be left at room temperature (not less than 20°C) for more than 8 days to fully cure. In order to shorten the curing time, the aging temperature can be performed at 40-65°C and the aging time is 24-48h.

4.121 °C retort sterilization composite film adhesive

The resistance to 121 °C retort sterilization composite film adhesive for the preparation of medium temperature cooking bag (121 °C sterilization 30min). Japan's resistance to 121 °C cooking sterilization packaging composite film polyurethane adhesive varieties and technical indicators in the table below.

The main agent model AD-502AD-1080AAD-1010EH-75A composition of solid content,%
Viscosity, mPa·s

Polyester polyol
50 soil 2
3500±500

Polyester polyol
60±2
1660
Polyester polyol
50±2
3500±500
Polyester polyol
60
1070-1760 Curing Agent Model CAT-10AD-1080BAD-RTIKW40 Composition Solids, %
Viscosity, mPa·s polyisocyanate 75 soil 27
50±750 polyisocyanate
75±100 420±lm polyisocyanate
70 Earth 2
150±50 polyisocyanate 40
250 main agents: curing agent (parts by mass) 100:7 100:17 100:7 5:1 Solvents Ethyl Acetate Hard, good resistance to content, suitable for compounding of different types of films, Extrudable compound AC agent 120°C , 30min) Excellent resistance to content, applicable to a variety of film composite (, 20t, 30min) for aluminum foil composite, resistance to content, excellent quality, hard, thick film, long reaction time (120 °C, 30min) strong bonding different types Film (120°C, 30min) Main Uses General Aluminum Plastic Cooking Aluminum Plastic Cooking Transparent Film Cooking Aluminum Plastic Cooking Boil Aluminum Plastic Cooking

1 Toyo Ink Manufacturing Company of Japan.
2 Dainippon Ink Chemical Industry Company products. (to be continued)

Eraser

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February 17, 2019