Why Transparent PET self-adhesive materials have become a packaging innovator in multiple fields ​

1. Material characteristics: the foundation for wide application ​
Transparent PET self-adhesive materials use polyethylene terephthalate (PET) as the core material. PET is a high molecular polymer, and its molecules are formed by condensation reaction of terephthalic acid and ethylene glycol. The regular linear molecular structure gives the material unique properties. The tightly arranged molecular chains give the material high strength. When pulled by external forces, the intermolecular forces can effectively resist deformation and ensure that the material is not easily damaged. At the same time, the moderate flexibility gives the material high toughness, and it will not break easily in the case of bending, twisting, etc., maintaining the overall shape stability. ​
The density of PET is within a specific range. This feature ensures that the material is solid and does not increase the burden of the product due to excessive weight. Its optical performance is particularly outstanding, with a uniform internal structure. When light propagates in it, there is very little scattering, and it penetrates almost without obstruction, thereby achieving a high transparency effect, so that the product information or graphics under the label are clearly presented.​
In terms of chemical stability, PET has a certain tolerance to common acid and alkali substances. When encountering a weak acid or weak alkaline environment, its molecular structure will not be easily destroyed, and the original performance of the material can be maintained. PET also has the ability to resist general organic solvents and will not swell or dissolve. This chemical stability enables transparent PET self-adhesive materials to maintain their own stable performance in a variety of complex chemical environments, without deformation, fading or corrosion problems, providing guarantee for its application in many fields. ​
2. Production process: the key link to determine product quality ​
In the production of transparent PET self-adhesive materials, the selection of raw materials is the primary key. High-quality PET raw materials have high purity, few impurities, and complete molecular structure. Drying the raw materials is essential, and the presence of water will have adverse effects in subsequent processing. If the raw materials contain water, during the high-temperature processing, the water vaporizes to form bubbles, causing holes and unevenness in the film, affecting transparency and strength; it may also trigger a hydrolysis reaction, destroy the PET molecular chain structure, and reduce the material performance. ​
There are many processes in the film forming process. Extrusion molding melts the PET raw material by heating, pushes it through the extruder screw, extrude it from a specific die head, and forms a film after cooling. Blow molding is to make the molten PET raw material into a parison, blow it up with compressed air to fit the mold cavity, and cool it to form a film. The biaxial stretching process is to stretch the PET sheet in the transverse and longitudinal directions under certain temperature conditions. During the stretching process, the molecular chains are arranged in an orderly manner along the stretching direction, which not only improves the strength of the film, but also enhances the transparency and dimensional stability. Transverse stretching improves the performance of the film in the width direction, while longitudinal stretching improves the performance in the length direction. The combination of the two gives the film excellent comprehensive performance. ​
The formed PET film needs to be surface treated. Corona treatment uses high-voltage discharge to generate free radicals on the surface of the film, introduce polar groups, increase surface roughness and polarity, and improve adhesion with glue and ink. Coating treatment is to apply a specific coating on the surface of the film, which also improves the surface performance and creates good conditions for subsequent printing and pasting. ​
In the glue coating stage, choose the appropriate glue according to the needs of different application scenarios. Permanent glue has strong viscosity and is suitable for occasions where labels need to be fixed for a long time; removable glue can be easily peeled off under certain conditions without leaving any glue residue, which is suitable for temporary labels or products that require surface protection. Use precision coating equipment to strictly control the thickness and uniformity of glue coating. If the glue is applied too thickly, it may cause the glue to overflow, affecting the appearance and use; if the glue is applied too thinly, the viscosity is insufficient and the label is easy to fall off. ​
The last step is the slitting and packaging process. The PET film coated with glue is slit according to the specified size, and the slitting accuracy affects the use effect of the label. Inaccurate size will cause the label to not fit perfectly with the product packaging. After slitting, the product is properly packaged, and appropriate packaging materials and methods are selected to prevent friction, extrusion, moisture and other factors during transportation and storage to ensure product quality. ​
III. Multiple uses: different fields that play an important role​
(I) Food and beverage industry​
The food and beverage industry has strict requirements on packaging materials, and transparent PET self-adhesive materials are widely used in this field. On all kinds of bottled beverage packaging, transparent PET self-adhesive labels can fit tightly to the various complex curves of the bottle. Through the label, consumers can directly see the appearance characteristics of the beverage, such as color and clarity. The brightly colored juice shows attractive colors through the transparent label, stimulating consumers' desire to buy; the clear mineral water, the transparent label makes its pure texture clear at a glance. The detailed production date, ingredient list, nutritional content and other information marked on the label provide important reference for consumers to help them make purchase decisions. ​
In terms of food packaging, from chocolate packaging, biscuit boxes to snack food packaging bags, transparent PET self-adhesive labels can play a role. While showing the appearance of food, it conveys brand information, product features and other content, and enhances the overall beauty and grade of the packaging. Moreover, the material has good weather resistance and stain resistance, so that it can still keep the label clear and complete in the face of environmental factors such as humidity, high temperature and dust during food transportation and storage, without blurring or falling off, ensuring that product information is always identifiable.​
(II) Cosmetics​
Cosmetics have complex ingredients, including alcohol, fragrances, surfactants and other chemical ingredients, which are corrosive to label materials. Transparent PET self-adhesive materials have become an ideal choice for cosmetic labels due to their excellent chemical resistance. On the packaging of skin care essences, creams and other skin care products, transparent labels can clearly display brand logos, ingredient descriptions, instructions for use and other information. During the storage and use of skin care products, the transparent PET self-adhesive labels will not be corroded by the chemical ingredients in them, and the integrity and beauty of the labels will always be maintained. ​
In terms of cosmetics, transparent PET self-adhesive labels have obvious advantages. Lipsticks, eye shadows and other cosmetics are colorful, and transparent labels will not cover the color of the product itself. Instead, they use the transparent characteristics to enhance the visual impact of the product. When consumers choose, they can see the true color of the cosmetics more intuitively, which improves the purchasing experience. At the same time, the exquisite appearance of transparent labels enhances the overall grade of cosmetics and meets consumers' demand for high-quality product packaging. ​
(III) Pharmaceuticals​
The accuracy and durability of pharmaceutical labels are related to the safety of patients' medication, and transparent PET self-adhesive materials play an important role in this regard. During the storage and transportation of drugs, they will be affected by environmental factors such as temperature and humidity. Ordinary labels are prone to fading, blurring, and falling off under these environmental changes, resulting in the inability to accurately identify drug information. The chemical resistance and stability of transparent PET self-adhesive materials enable it to effectively resist interference from environmental factors. Whether in a high-temperature and humid environment or a low-temperature and dry environment, it can ensure that key information such as the drug name, specification, usage and dosage are clearly identifiable, avoiding medication errors caused by labeling problems, and providing reliable protection for the safe use of drugs. ​
In addition to the above-mentioned fields, transparent PET self-adhesive materials are used in the field of electronic products for product labels such as mobile phones and computers, marking product models, parameters and other information; in the field of daily necessities, they are used in product packaging labels such as shampoo and shower gel to display product efficacy, ingredients and other content; in the field of luxury goods, they are used for exquisite packaging of high-end jewelry, watches and other products, highlighting the noble quality of the product in a low-key way. ​
IV. Significant advantages: core elements that stand out​
(I) High transparency​
High transparency is a prominent advantage of transparent PET self-adhesive materials. With its own optical properties, it can make the product information or graphics under the label clearly presented, achieving an almost "invisible" display effect. In glassware, crafts, food and beverages, etc., where the appearance or color of the product needs to be displayed, transparent PET self-adhesive materials make the product the visual focus. Consumers can directly observe the details of the product without being blocked by the label, effectively improving the product's attractiveness and display effect, and enhancing consumers' willingness to buy. ​
(II) Good physical properties​
Transparent PET self-adhesive materials have high strength, high toughness and good dimensional stability. High strength enables it to effectively resist damage when subjected to external forces. During the transportation and handling of the product, even if it encounters collisions and extrusion, it is not easy to be damaged. High toughness gives the material a certain flexibility, which can adapt to product packaging of different shapes and will not break when bent or twisted. Good dimensional stability ensures that the material has little dimensional change under different temperature and humidity environments. Whether the material does not expand significantly in a high temperature environment or does not shrink and deform in a low temperature environment, it can ensure that the label fits the product packaging perfectly without affecting the use and appearance.​
(III) Excellent chemical stability​
The chemical resistance of transparent PET self-adhesive materials enables them to maintain stable performance in product environments containing chemical ingredients. In the fields of cosmetics and pharmaceuticals, it will not corrode or fade in the face of complex chemical ingredients. Transparent PET self-adhesive labels can maintain their performance when exposed to various ingredients in cosmetics for a long time, or when exposed to possible chemicals during the storage of pharmaceuticals, ensuring that the labels are clear and complete for a long time, meeting the strict requirements of different industries for the chemical stability of label materials.