⑵Water-based varnish The water-based varnish contains about 40% of solid components, and the remaining 60% is water, which is dried by physical methods. The advantages of applying water-based varnish are: ①The coating has excellent gloss; The disadvantages of applying water-based varnish are: ①When using lightweight paper, the printed sheet may curl due to water absorption; ⑶UV curing varnish UV-curable varnish contains more than 99% of solid components. It is "dried" by radiation curing. In fact, the entire coating is polymerized into a solid film under UV irradiation. The curing effect depends on the wavelength of UV light emitted by the UV lamp. And radiated power. The advantages of applying UV-cured varnish are: ①Gloss coating can produce extremely high gloss; The disadvantages of applying UV-curable varnish are: ①Mechanical equipment is expensive; 3. Coating amount of varnish Talking about the coating amount of varnish, first of all, the coating amount of dry film and wet film should be distinguished. The ratio of the amount of dry film coating to the amount of wet film coating is approximately equivalent to the proportion of solid materials in the varnish in the total materials. This ratio averages 75% when using oil-based varnishes and about 40% when using water-based varnishes. For example, if the wet film coating amount of the aqueous varnish is 10g / m2, then the dry film coating amount is about 4g / m2. Usually water-based varnish is divided into light and light, the actual use depends on the packaging design requirements. The coating amount of aqueous varnish is generally 6-8g / m2 (wet film). The thickness of the coating film can be expressed in micrometers. At this time, the ratio of the thickness of the dry film to the wet film can also be the above ratio. At present, there is no reliable method for measuring the wet film coating thickness of printed products on the machine. When carrying out long-run operations, the consumption of varnish can be calculated based on the total coated area on the printed sheet. The smoother the paper surface, the better the gloss of the gloss coating. The thickness of the water-based varnish coating film when dried is twice as thick as the oil-based varnish coating film. The same thickness of water-based varnish coating can show a higher gloss. There are Other Stainless Steel Kitchenware, such as stainless steel pots, stainless steel pans and more. Retaining the taste of food is the great advantages of Stainless Steel Kitchenware.The stainless steel keeps the taste and flavor unchanged. Moreover, it does not add any metallic taste to the food. Even the Stainless Steel KitchenWare does not react with the alkaline and acidic food and ensures the food safety. If the food safety is maintained properly, then the food value and nutrition of the food will remain unchanged. Other Stainless Steel Kitchenware Kitchen Utensils,Kitchen Skimmer,Onion Chopper,Vegetable Chopper Yangjiang Superwins Trade Co., Ltd. , https://www.steelkitchenware.nl
â‘¡The coating has excellent wear resistance;
â‘¢The water-based varnish dries quickly after coating;
â‘£After applying water-based varnish, there is no need for powder spraying or only a small amount of powder spraying;
⑤The stability of printed products is good;
â‘¥ The coating will not turn yellow;
⑦Water-based varnish has no bad smell, and its application field is rarely restricted.
â‘¡It is difficult to apply partial coating (coated with metering roller).
â‘¡The coating is strong and durable;
â‘¢As long as the UV lamp can meet the requirements for use, the UV-cured varnish coated on the printed product can be dried instantly;
â‘£ No need to spray powder after coating, no adhesion of printed products will occur;
⑤ The coating has high abrasion resistance.
â‘¡The cost of ultraviolet curing varnish is high, and the cost of energy consumption is also high;
â‘¢ Not completely odorless;
â‘£ It is difficult to apply UV curable varnish directly on the printed matter printed with ordinary offset printing ink. It must occupy two coating and glazing units, the first one is primer, and the latter is glazing.
Discussion on the Coating and Polishing Process of the Printed Surface (2)
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