Development of Aluminum Foil Protective Coating for Medicine Packaging (Part 1)

Abstract: Use thermosetting acrylic resin, nitrocellulose, etc. to make aluminum foil for pharmaceutical packaging Protective paint. The production process of the resin, the preparation and performance of the paint are introduced, and various influencing factors are discussed.

Keywords: pharmaceutical packaging aluminum foil thermosetting acrylic resin nitrocellulose protective coating

The aluminum foil blister packaging of medicines is currently the most widely used medicine packaging method. It has the advantages of moisture-proof, safety and sanitation, long shelf life, and convenient to carry and use. At the same time, it also has the advantages of low cost, fast production speed, and convenient transportation. Aluminum foil for pharmaceutical packaging is generally composed of 5 parts: protective layer, outer printing, aluminum foil base material, inner printing, and adhesive layer. The main role of the protective layer is:

(1) Modify the surface of the aluminum foil to make the surface of the aluminum foil bright and smooth, and inlay the surface of the aluminum foil Small gaps.

(2) Improve the acid and alkali corrosion resistance of aluminum foil and extend the shelf life of medicines.

(3) It has a certain degree of hardness and adhesive strength to protect the printing ink on the outside, It adheres well to the aluminum foil substrate and does not fall off. During high temperature compounding (150—180°C), the coating will not stick to the machine stick of the medicine packaging machine because of softening and stickiness. In this test, thermosetting acrylic resin is used, through the combination of appropriate nitrocellulose, additives, solvents, etc., to obtain good heat resistance, strong adhesion, full coating, rapid drying, good unwinding, and excellent performance for pharmaceutical packaging. Aluminum protective coating.

1 test part

1.1 raw materials and equipment

1.1.1 Main raw materials and specifications

methyl methacrylate, industrial grade; butyl acrylate, industrial grade; methyl Acrylic acid, industrial grade; acrylamide, industrial grade; formaldehyde,

industrial grade; initiator, reagent; auxiliary, industrial grade; nitrocellulose ,

industrial grade; solvent, industrial grade.

1.1.2 Test equipment

Super constant temperature water bath; electric heating mantle; electric stirrer; X-1 rotary blade type Vacuum pump; constant temperature drying oven; commonly used glass instruments.

1.2 Synthesis of thermosetting acrylic resin

1.2.1 Recipe

The thermosetting acrylic resin formula is shown in Table 1.

 
1.2.2 Synthesis process

In a four-necked flask equipped with a stirrer, reflux condenser, and thermometer, add Human solvent methanol. Start stirring and heat up. Under the reflux temperature, the reaction monomer and initiator are added dropwise in a certain order. After all the drops are finished, react for 2 h. Then, toluene was added, and the methanol was distilled off. After the methanol is completely evaporated, the temperature is lowered to obtain a thermosetting acrylic resin.

1.2.3 Technical indicators of thermosetting acrylic resin

The technical indicators of thermosetting acrylic resin are shown in Table 2.

1.3 Preparation and performance of aluminum foil protective coating for pharmaceutical packaging< /p>

1．3.1 Paint making

Add thermosetting acrylic resin, nitrocellulose, additives, solvents according to the formula , Stir evenly, then

 
2 Results and discussion

2.1 Selection of raw materials

The important performance requirement of aluminum foil protective coating for pharmaceutical packaging is formed on hard aluminum foil The protective layer has a strong adhesion to the aluminum foil, and has a higher hardness without sticking when it is laminated at high temperature and hot pressing (150—200°C:). Nitrocellulose has good tensile strength, high hardness, and fast release of solvent. When its content reaches a certain level, it can meet the hardness requirement. Thermosetting acrylic resin is used as a protective or modified coating on metal surfaces. It has excellent performance in all aspects after curing, and has excellent gloss retention, color retention, corrosion resistance, heat resistance, and high adhesion. After comprehensively considering the properties of the two resins, nitrocellulose and thermosetting acrylic resin were selected as the main film-forming materials of aluminum foil protective coatings for pharmaceutical packaging to ensure that the protective layer has good hardness, adhesion, heat resistance and Corrosion resistance.