In Feb, HOTSALES, Pakistan customer order 15pcs zinc plates.

In Feb, HOTSALES, 15pcs zinc plates are packed for delivering to our customer in Pakistan.High quality zinc plates with good packing.

Powder-free corrosion zinc plate making plays a pivotal role in letterpress printing, packaging printing, and anodized aluminum hot stamping. Its plate making process is relatively complicated. To make a printing plate that meets printing requirements, one must be familiar with its technology and operate on each link. Strictly check, otherwise it is easy to produce quality accidents, the process operation is briefly described as follows:

1. The principle of powder-free corrosion of zinc plate. Powder-free corrosion of zinc plate is based on the impact theory and heat-temperature theory, which is the result of physical and chemical effects. The additive is added to nitric acid under mechanical stirring, and the surfactant disperses the oil evenly in the nitric acid solution with very small oil droplets to form an emulsion. During the corrosion process, the emulsified oil forms a thin layer. The protective film, due to the difference in adhesion on the layout, achieves the purpose of corrosion through the vertical impulse of the machine. During the corrosion process of the constant-temperature corrosive solution, because the blank part of the zinc plate is corroded to generate chemical reaction heat, and the part of the graph is not corroded and does not generate heat, the temperature difference of the layout is formed. A range is formed where the blank meets the plot line. In this way, the protective power of the protective film on the adsorption plate of the additive is also different, and the corresponding resistance to the impacted corrosive liquid is generated, so a slope layer is formed to meet the printing requirements.

2. Zinc plate and protective agent

1. The zinc plate for powder-free corrosion is a special zinc plate for microcrystalline, with a grain size of 0.005~0.01mm and a thickness of 0.8, 1.0, 1.6mm (± 0.01mm). The various zinc plates produced in my country vary slightly from place to place. The zinc plate produced in Shanghai has high magnesium content, low cadmium content, fast corrosion rate, strong adaptability, easy to master, and poor hardness: the zinc plate produced in Guangzhou has high cadmium content, good hardness and high printing durability. The grain size of the microcrystalline zinc plate has a close relationship with the baking temperature. It increases with the increase of temperature. The crystallization will not corrode if it exceeds 0.02mm. Generally, the baking temperature should be controlled between 180C and 200C.

2. The protective agent is also known as an additive, which is specially sold in the market. It is composed of two parts, an oil agent and a surfactant, mainly castor oil. Penetrating agents, etc., and protecting agents should be stored at room temperature, do not over-cool or over-heat. The oil agent is composed of refined alkane benzene, natural light oil, tea, etc., and plays a protective role. Among the surfactants, the Huang castor oil plays the role of penetration and emulsification, and has a protective effect: the sodium alkyl zanthium plays the role of penetration and improves the emulsification; the penetrant T plays the role of penetration and emulsification and improves the stability of the Huanghua oil; 0II-4 plays the role of emulsification, dispersing the oil evenly, and making the geology smooth and particles finer. In addition, there are sben 80 and antifreeze to prevent delamination.

3. Face lotion and anti-numbing agent

1. The whole surface is to remove the oxide layer impurities on the zinc plate to avoid pitting caused by corrosion and the phenomenon that some parts cannot be corroded. The whole surface should be uniform and not hurt the line drawing. The preparation of the whole face lotion is as follows:

Nitric acid

200cc

water

2000cc

B148°

2. The function of the anti-numbing agent is to prevent the oil molecules from sticking to the zinc plate and causing accidents when the zinc plate and the corrosive liquid begin to contact. Before the corrosion, the anti-numbing agent is evenly distributed on the plate surface, and the action should be fast during operation. Some, do not let the zinc plate surface dry and stained with oil. The anti-anesthetic solution is prepared as follows:

water

500cc

Nitric acid (reagent)

500cc

Sodium Phosphate 230g

Liquid B

water

500cc

Sulfuric acid (reagent)

600cc

Potassium hydroxide

2g

After the temperature is lowered, mix the two liquids and add water 3 to 5 times.

Four, powder-free corrosion zinc plate T art operation

The operation of powder-free corrosion zinc plate I process is as follows: drying plate, baking plate, repair plate-corrosion one whole plate

1. Printing

①Whole surface; grind the surface of the zinc plate with charcoal or soak it in 10% nitric acid to remove the oxide layer, grease, etc. of the plate, so that the photosensitive solution can be evenly and firmly attached to the plate.

②Baking plate: pre-determine the temperature and speed of the plate drying machine, clamp the milled zinc plate on the plate frame, turn it on and rinse the plate blood with water, then apply photosensitive glue and dry it, the general temperature is 50C, and the speed is 60 ~

80n, time 5~10 minutes.

The photosensitive solution is prepared as follows:

nail polish

PVA (Polymerization degree 500, water soluble 85~90'C)

100g

water

1000cc

After steaming for 1.5 hours, filter (about B14°)

Liquid B

Ammonium dichromate

10~ 14g

water

100cc

When the liquid A is cooled to 45C, the two liquids are mixed. .

If the polymerization of PVA used is too high, it is easy to paste the plate when printing, and a small amount of sodium fluoride, ethanol, glacial acetic acid, etc. can be added when the A solution is cooked.

③ Exposure; after the film is dried, it is relatively close to the negative film and placed in a vacuum printing machine for compaction for exposure. The light source can be xenon lamp or other lamps. The general lamp distance is 0.5~1m, and the time is 3~5 minute.

④Development: Rinse off the non-photosensitive film with water after exposure. For the convenience of observation, dye it with 1% methyl solution until a clear image is displayed, and then rinse it clean.

⑤ Hard film: soak in 10% chromic acid solution for 20~30s, rinse with water immediately, rinse clean and place on a dry plate rack to let it dry naturally.

2. Bake the dried zinc plate with an electric furnace or an oven. The adhesive film on the zinc plate changes from yellow to a firm brown-red corrosion-resistant film. The baking temperature is 180C~190C, and the baking time is about 10 minutes.

3. Use a scraper to repair the unwanted part of the zinc plate, and use cleaning or epoxy resin to repair the incomplete part of the image. In order to save the corrosion potion, the blank part of the large zinc plate can be smeared.