Thin film panels, also known as film surface stickers, are widely used in industries such as household appliances, electronic instruments, medical equipment, and mechanical equipment. The following is a summary of the basic requirements and material types of film materials for film surface stickers, as well as the selection considerations. What are the requirements for film materials?
Films are very important for film surface stickers. In order to produce higher quality products, each material selection needs to be careful, especially when choosing films, because there are many types and models of films. Each material has various characteristics and disadvantages, so what are the requirements for surface stickers for film materials?
1. The film should have a good appearance: it means that the surface of the film used to make the panel is smooth, with a consistent gloss, and there are no surface defects such as mechanical damage, scratches, inclusions and stains.
2. Have better chemical resistance: the panel layer may touch different chemicals, but for most common chemicals, such as alcohols, ethers, and mineral oils, it should have a certain tolerance .
3. Good weather resistance: the panel layer is the surface layer of the film surface that is exposed to the natural environment. The panel material must be able to withstand certain natural environmental conditions without deformation, cracking, aging and discoloration.
4. Good dimensional stability: film surface stickers require that the film of the panel be made without significant change in size within a certain temperature range, and the temperature is generally between minus 40 and plus 50 degrees.
5. Requirements for elasticity: It is required that the panel layer is thin and has a certain resilience. At the same time, the elastic deformation of the film surface is small, which can be judged by the elongation rate of the material. Generally speaking, the elongation rate is large, and the elastic deformation is also large. Difference.
According to the requirements of the above five aspects, we are looking at the types and characteristics of materials often used in actual manufacturing according to the requirements.
Polyester film (PET)
The surface state of PET film is generally a smooth transparent film, and in a few cases, there are also products with a sandy surface, such as KB products from Japan's Kimoto Company, and Ketutai's F150 and F200. Polyester film has better elasticity and temperature resistance, and its price is between polycarbonate film and polyvinyl chloride film. However, because the surface of the film is difficult to process into a matte texture, most of them are transparent sheets. At the same time, the surface of the polyester film cannot obtain satisfactory printing effects for most plastic inks. Generally, specific special inks are required. Ensure good subsequent processing performance. Because the general performance of PET film can be replaced by PC film, it is not used for panel materials too much, except in some special occasions, such as insulation, resilience, solvent resistance, etc., which cannot be satisfied by other films. There are only a small number of applications in this case. To sum it up is: solvent resistance, good insulation, long life.
PET/-30~120℃/0.1~0.2 smooth surface Good chemical resistance, insoluble in general organic solvents, not alkali resistant. It has excellent mechanical properties, electrical properties, rigidity, hardness and the greatest toughness among thermoplastics, low water absorption, excellent wear resistance and friction resistance, and high dimensional stability. The tensile strength is comparable to aluminum film, much higher than PC and PVC. Inexpensive Because the surface is difficult to process into a matte type, textured PET is more expensive. It is the most ideal substrate for making membrane switch circuits. Among them, textured PET is suitable for products with higher surface requirements or with liquid crystal display windows.
Polycarbonate film (PC)
PC material can be divided into sand surface and glossy surface. The comprehensive index of physical and chemical properties of PC material is good, and its adaptable ink is also widely used. It is the most common material used in the key switch panel layer of film panel. The polycarbonate film has a wide temperature range (-60~100°C). When the temperature or humidity changes, the performance of this material does not change much, thus ensuring that the panel can be used in various instruments and various harsh environments . However, its disadvantage is that it is more sensitive to solvents, and solvents with strong solvation effect are easy to make it embrittled and cracked. To sum up: the comprehensive index is very good, but it is not resistant to solvents.
PC/-60~100℃/0.175~1.0/ smooth surface has high light transmittance, low water absorption, good dimensional stability, excellent bending resistance, tensile strength and compressive strength, heat resistance and cold resistance, electrical insulation and Excellent resistance to atmospheric aging. The chemical resistance is poor, the fatigue resistance is poor, and stress cracking is easy to occur. The output interface terminal circuit is generally printed with carbon materials, and there is no protective coating. It is gradually oxidized by air to form a peeling layer, and finally leads to open circuit. End of life, this is where the membrane switch is most likely to fail, mainly determined by the environment, regardless of whether it is used or not, the physical damage time is 3-10 years. Generally, the scope of application is the widest. In addition to meeting the requirements of most membrane switch panels, the high light transmittance of glossy PC can even meet the requirements of liquid crystal display windows.
Polyvinyl chloride film (PVC)
The price of PVC film material is relatively low, about one-half of that of PC material. When producing civilian and popular products, if PVC material is selected, the production cost can be reduced. At the same time, PVC material has good ductility and can be processed by cold pressing. Three-dimensional graphics. The temperature resistance of polyvinyl chloride film is poor, especially under high temperature conditions, its softening temperature is 59 ℃, and its elasticity is not as good as that of polycarbonate film. But it has a high elongation (130%), and because of its low price, it is suitable for use under normal conditions. To sum it up: cost reduction, small temperature range, and good extensibility.
In addition to transparent PET, there is also a PET of frosted material on the market, such as Ketutai's F150 and F200 materials. Their main advantages include: first, scratch resistance, abrasion resistance, bending resistance, fine and uniform abrasive grains, high-grade and soft surface effect; second, the printing surface is treated with a special coating, which is suitable for most ordinary PVC inks It has good adhesion; third, the matte layer has excellent adhesion, and the punching and stamping appearance will not appear stamping bursts, and the matte layer will not fall off; fourth, the matte material uses a special window opening fluid, which is easy to make Re-obtain a clear window at the window opening position; fifth, it has a good convex hull effect, easy to make a convex hull, and can be formed by cold pressing or hot pressing; sixth, it has good chemical resistance, and can resist alcohol, ketones, Cleaning of chemicals such as cleaners, solvents, and weak acids; Seventh, frosted PET materials have a better service life than PC, PVC and other materials. The life of the button is more than 1 million times.
Above we have introduced the three main materials and their characteristics and properties for making film-faced panels. The following are the precautions: From this we know that PVC materials are not widely used because of their poor adaptability and non-environmental protection. Compared with PC materials, PET materials are harder and have a longer life. Therefore, the film surface stickers with high frequency of use and large force on the button need to use PET as the panel material. For example, we use washing machines in our daily life, which is a household appliance with high frequency of use, so the panel material of the washing machine switch is very important. If the panel is made of PC material, the lifespan is not as good as that of the product using PET material. Therefore, for household appliances with high frequency of use, such as washing machines, it is a correct choice to use PET as the panel material. PET material can be used not only for printed panels, but also for printed circuits. It is an ideal material for making circuits. It has good insulation, heat resistance and high ink adhesion.
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