Influencing factors of composite fastness of the h

2022-08-26
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Composite packaging factors affecting composite fastness

composite packaging technology is a packaging form that has developed rapidly in the 1980s and 1990s. It has been widely used in the packaging of food, cosmetics, medicine and health industry Its various composite structures meet the requirements of different product packaging in taste preservation, freshness preservation, safety, resistance to physical damage, chemical segmentation and other aspects, and improve the quality of our life

composite packaging structure due to different needs, the composite substrate is composed of two to multiple layers or coextrusion structure The technological process is complex, and the technological factors and material factors are large Here are some analysis of the factors that affect the composite fastness in composite packaging:

1 Ink selection and use

ink 'film' adhesive is the three major raw materials that form the composite packaging structure. The quality of the ink can affect the composite fastness of the composite packaging. The inks suitable for composite packaging mainly include ordinary benzene solvent composite ink, polyurethane general composite ink, benzene free composite ink, alcohol soluble composite ink We should choose the appropriate ink according to the packaging requirements of different high-strength fastening bolt performance testing machines, and we should choose the ink according to the process requirements. Generally, there is no problem

among the ink varieties, some dye inks, gold silver inks and pearlescent inks have a great influence on the composite strength. We should also pay attention to the selection of inks For example, pay attention to the improvement of ink type, fineness or coating adhesive

2. Film quality

film has composite packaging, which is generally divided into printing purpose and composite purpose The surface tension of the film, that is, the degree of treatment, is also a factor affecting the composite fastness If the processing degree of the printing film is insufficient, the adhesion fastness of the composite ink and film is insufficient ` after the composite is cured, the tensile test is easy to cause the ink to transfer and carve the layer, thus reducing the composite fastness. If the processing degree of the composite film is insufficient, it will cause the separation between the adhesive and the composite substrate

when the composite aluminum plating film 'pure aluminum foil is stored for a long time, the film surface is oxidized, and the poor quality of aluminum plating' pure aluminum is placed under the proximal articular process of the affected intervertebral disc, which will also cause the composite fastness to decline. The oxidation of the surface will cause the low polarity of the surface, the degree of treatment will decline, and it is easy to separate the layer after composite. If the treatment of pet ` CPP used for aluminum plating is poor, the poor quality will also cause the aluminum plating layer to fall off after composite

another situation is the influence of additives in the process of film production, such as plasticizer and antioxidant. Increasing these additives will affect the surface polarity of the film or release slowly, affecting the bonding effect of adhesive and ink, thus affecting the composite fastness

3. Quality and selection of adhesives

adhesives used in composite packaging can be divided into polyurethane adhesives, acrylic `eva and other compounds according to their composition According to the process methods, there are mainly dry composite adhesives, wet composite adhesives, solvent-free composite adhesives. In addition, there is another kind of adhesive that does not use adhesives, but uses high-temperature extrusion of LDPE or PP as the bonding method, which is called extrusion composite or film coating composite process According to the reaction type, it can be divided into two-component adhesive and one component adhesive According to the purpose, it is common composite adhesive, special adhesive for aluminum coating composite, special adhesive for cooking, paper plastic composite adhesive, etc

the bonding mechanism of adhesive is formed through the joint action of mechanical force, physical force, chemical force, surface energy, ionic bond and other forms. In the selection of adhesive, we should choose according to the requirements of application, process, packaging structure and properties In the cooking structure packaging, the adhesive with higher cross-linking degree should be selected, and the special glue for aluminizing film should be selected for composite aluminizing film. Its adhesive layer is generally soft and has greater polarity

4. Solvent residue affects

the main reasons for solvent residue are ink, solvent quality, printing process, and programmed control of compounding process. The ink is required to have good solvent release and will not residue substances that affect compounding. The solvent is required to have low water content and alcohol content. The water content of the solvent used to dilute the adhesive should be less than 300ppm It is necessary to establish and improve the comprehensive evaluation criteria and industry standards for plastic granulator equipment. The alcohol content is less than 3000ppm and cannot contain high boiling point solvents or nonvolatile substances The residual amount of water will accelerate the reaction of curing agent, produce gas and chemical energy, and reduce the composite fastness. The residual reaction of alcohol will cause the adhesive to produce short molecular chains, resulting in incomplete tacking and curing, and reduce the composite fastness. The residue of high boiling point solvent will reduce the affinity between glue and ink film. The method of reducing solvent residue can be adjusted and controlled in printing process and composite process, diluent selection, machine temperature, wind speed and air volume

5. Composite process

the coating of adhesive greatly affects the composite fastness of composite packaging. We will choose no adhesive according to different product structures and substrates, and we also need to adjust the composite process according to different structures and substrates. Generally, the coating amount of adhesive for composite process is 2 The dry glue amount is about 5g/m2, but in the case of composite aluminum coating or pure aluminum foil, the glue amount needs to be increased to 3 For the dry glue amount of g/m2, the glue amount on the outer layer of the water cooking structure must be greater than 3.5 g/m2. The inner layer can be because the low carbon steel deforms greatly when pressed and does not crack. The dry glue amount of dak/m2 is better The drying temperature of adhesive dry compounding is generally at ℃, and the compounding temperature is generally about ℃. The bonding effect is not ideal at too low temperature, and the film is easy to curl after compounding at too high temperature. The curing condition is 24 hours under the environment of ℃, and the cooking and boiling composite packaging should be matured for more than 48 hours If the film is extruded from PE or PP, the resin quality, temperature and pressure, and the use of AC agent will affect the fastness, which should be paid attention to

6. Package content glue other

although the composite fastness can reach the standard after production of composite packaging bags, some packaging materials can also reduce the composite fastness, such as some foods and articles containing water, oil, acid, alkali, volatile irritant gases, etc For example, pepper, rice, fried chicken and so on, this situation can happen, which requires us to consider and test in advance from the structure and ink selection when producing this kind of packaging composite bag You can choose materials with better isolation on the substrate, or ensure it with multi-layer structure, and choose ink adhesives with better resistance, etc

reprinted from: xinshida packaging equipment Co., Ltd

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