Aluminum foil is a high-grade packaging material that can replace a large area of ​​aluminum foil stamping and hot stamping. The printed products are magnificent. It not only improves the grade of packaged goods, but also improves the display value of packaged goods. It is widely used in high-end products. Trademarks and packaging. Aluminum foil is also widely used in the food and pharmaceutical packaging industries. Aluminum foil and plastic film composites effectively use high-temperature cooking and complete shading. It can be used as a cooking bag to package cooked foods. Multi-layer composite films are also used. For biscuits, snacks, drinks and other small food packaging. Aluminum foil is characterized by: metallic luster, good light protection, high heat and light reflective ability, metallic luster and reflection ability can improve the brightness of the printing color; good insulation, strong protection, gas-impermeable body and water vapor, Prevent moisture absorption and vaporization of the contents, which are not easily invaded by bacteria and insects. The shape has good stability and is not affected by humidity changes. Easy to process, can be printed on aluminum foil, color difference, embossing, surface coating, gluing, etc.; can not be forced, no sealing, pinhole and wrinkle, so under normal circumstances not alone Use, usually with paper, plastic film processing into a composite material, to overcome the lack of sealing defects, insulation and other advantages have also been fully utilized. Aluminum foil printing can use relief printing, gravure printing and flexo printing. Toppan printing is suitable for small-lot printing, and gravure printing and flexo printing are suitable for large-volume roll paper printing. The following measures must be taken during the printing process: greater printing pressure is required. Aluminum foil has strong barrier properties and poor absorption. The pressure causes the surface of the printing plate and the aluminum foil to come into contact with the largest area and forces the ink to adhere. Requires strong ink adhesion, drying speed, fast. Printing ink can be used, resin type offset printing fast fixing ink or offset printing ink and plastic ink. Ink is generally required to add driers to improve the drying speed, such as gravure printing must be installed hot air drying device. Before selecting the ink on the machine, you must first make a small sample to test whether the hue and dryness meet the requirements. A blackboard (also known as a chalkboard) is a reusable writing surface on which text or drawings are made with sticks of calcium sulphate or calcium carbonate, known, when used for this purpose, as chalk. Blackboards were originally made of smooth, thin sheets of black or dark grey slate stone. Hanging Chalkboard,Custom Chalkboard,Portable Chalkboard,Wood Framed Chalkboard Jinan Tri-Tiger Technology Development Co., Ltd , https://www.jinanfurniture.com
Roll materials need to have the right printing speed and tension. If the printing speed is too fast, the drying speed of the ink will be affected. If the tension is too large or too small, the aluminum foil may break or wrinkle and affect the printing effect. The main role of vacuum aluminum film vacuum aluminum film is to replace the aluminum foil composite, so that soft plastic packaging also has a beautiful silver-white gloss, improve the soft packaging film bag barrier properties, shading, thereby reducing costs. The vacuum-plated substrate film is a polypropylene film with a relatively high melting point, including CPP, IPP, and BOPP. The PET film, NY film and paper can also be directly vacuum-plated after pretreatment or humidity conditioning treatment. PE film and PT can be indirect aluminum plating technology. In order to improve the degree of aluminum plating, foreign countries adopt the method of coating the bottom layer on the substrate film to be plated. In China, there is generally no bottom coating surface, and corona treatment is only performed on the surface.
A blackboard can simply be a board painted with a dark matte paint (usually black, occasionally dark green).Matte black plastic sign material (known as closed-cell PVC foamboard) is also used to create custom chalkboard art.Blackboards on an A-frame are used by restaurants and bars to advertise daily specials.
A more modern variation consists of a coiled sheet of plastic drawn across two parallel rollers, which can be scrolled to create additional writing space while saving what has been written. The highest grade blackboards are made of a rougher version porcelain enamelled steel (black, green, blue or sometimes other colours). Porcelain is very hard wearing, and blackboards made of porcelain usually last 10–20 years in intensive use.
Lecture theatres may contain a number of blackboards in a grid arrangement.The lecturer then moves boards into reach for writing and then moves them out of reach, allowing a large amount of material to be shown simultaneously.
The chalk marks can be easily wiped off with a damp cloth, a sponge or a special blackboard eraser usually consisting of a block of wood covered by a felt pad. However, chalk marks made on some types of wet blackboard can be difficult to remove. Blackboard manufacturers often advise that a new or newly resurfaced blackboard be completely covered using the side of a stick of chalk and then that chalk brushed off as normal to prepare it for use.