Plastic composite packaging films are made of multiple single-layer films, and their identification methods are also different from single-layer films.
Method for identifying composite film
First, combining the performance characteristics of the single-layer film and the requirements of the composite purpose can be roughly distinguished. As judged by transparency, aluminum foil, aluminized film, etc. are generally opaque composite films; with high barrier function, they are generally composite films.
The base film materials can be roughly judged from the appearance and mechanical properties of the film, such as high-strength PET , puncture-resistant PA , and easy-to-tear PP ; PET and PA are generally compounded with PE or CPP to solve the heat sealing problem.
1. Four tips for identifying composite films
â‘ The composite film generally has a natural curling phenomenon, which is more obvious if it is placed in hot water.
â‘¡When the material of the innermost layer and the outermost layer of the composite film are different, the two sides of the film have different feels and can be distinguished by careful touch.
â‘¢ Cut a small hole in the film, and then slowly tear it diagonally. It is easy to separate the layers of the composite film composed of substrates with different tear properties.
â‘£ If it is a printed film, if the printed layer does not rub off, it means that the printed layer is sandwiched between two layers of film, which is a composite film.
2. Physical property determination method to distinguish composite films with different structures
More reliable is the physical property measurement method, that is, thermal analysis is used to obtain the thermal spectrum, and the judgment is made according to the characteristic temperature in the figure. If the composite film is PP / PE , PET / PE , PA / PE, etc., the corresponding spectrum will appear The melting temperature peak of each component.
3. Microscope method to identify composite film
Microscopy can also identify composite films, because the refractive index of various plastics is different, and the birefringence value after stretching is different. When observed under a phase contrast or polarized microscope, the composite layers will show different colors, which can be distinguished Single membrane and composite membrane. After being determined as a composite film, each of its components should be separated and identified.
â‘ Stripping method.
For the composite film made by extrusion or dry lamination, after pulling or kneading, peeling occurs due to inconsistent deformation; a certain heat treatment is performed to soften the adhesive layer and peel the bonded film; also The crystalline polymers can be separated according to their different melting points.
â‘¡ Dissolution method or solvent method.
Different resins dissolve or swell differently, or change the interfacial tension after the solvent penetrates into the interface to separate the layers of the composite membrane.
After separating the base materials of the composite film, to find out which kinds of base materials are combined, the base material of the peeled composite film can be analyzed and determined, but at this time, the interference of the adhesive should be paid attention to.
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The so-called makeup remover refers to water-based cosmetics that remove light makeup. The water-soluble ingredients in the product combine with the dirt on the skin to achieve the purpose of quick makeup removal. Usually the formula contains surfactants, moisturizers, polyols, and some oily ingredients to increase the cleansing effect on the skin.
Excessive cosmetics and grease residues on the skin will not only block the pores, but also cause dull skin tone and affect the health of the skin. Do a good job of removing makeup before taking a break at night to take care of your facial skin.
It is suitable for removing makeup and waterproof makeup. Most of the water in the makeup remover can ensure the moisture content of the skin. Compared with other makeup removers, the makeup remover has the advantage of being more refreshing, but because the makeup remover has less oil in the water and contains more surface activity Agents and alcohols need to be used together with a cotton pad, which is especially suitable for sensitive skin.
Since the water-based makeup remover effect is weak, in order to improve its makeup removal ability, the market has launched a double-layer makeup remover, that is, a water + oil system. Shake it first when using it. It can easily remove water-based and oily makeup. Suitable for lips and face.
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