Glossy printing of the hottest plastic packaging p

2022-08-24
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Glossy printing of plastic packaging products

Plastic packaging products, whether films, bottles, pallets, turnover boxes, corrugated boxes, generally need to be printed on the surface, and the printing quality of the surface of plastic products, in addition to the printing fastness, that is, the adhesion of ink on the surface of products, gloss is also an important indicator. According to the gloss of printed matter, plastic printing can be divided into gloss, semi gloss and extinction. In order to make the surface of printed matter have good gloss, it is generally necessary to gloss the surface of printed matter after surface printing

most plastics have good transparency. Therefore, when plastic films or transparent plastic products are reverse printed, the modified and high value-added utilization of engineering plastics such as automotive plastics have good gloss. However, when positive printing, that is, surface printing, the ink often lacks gloss due to the large amount of solid components contained in the ink. The gloss of a plastic packaging product printing is not only related to the gloss and flatness of the printed surface, but also related to the composition of the printing ink and the thickness of the print. The higher the surface finish of the printed substrate, the better the gloss; The better the flatness, the better the gloss. The higher the insoluble solid components in the printing ink, the worse the gloss, the higher the extinction, and the greater the thickness of the printing layer, the worse the gloss

the gloss treatment methods of printing are as follows:

(I) coating the polish on the printing surface

this is a relatively convenient method, that is, on a six color intaglio printing machine, after the last color is printed, a concave eye coating roller coated polish is printed. The formula of polish is as follows:

Polish Formula 1: ethylene peroxide Polish

ethylene peroxide resin 20%

dehydrated benzoic acid resin company's managing director Gerry Boyce said or rosin resin 5%

toluene: ethyl acetate: cyclohexanone =1:1:1 75%

Polish formula 2: two-component polyurethane Polish

use dry composite two-component polyurethane adhesive as polish, Because this polish has good adhesion, excellent gloss after drying and film-forming, and is resistant to acid-base organic solvents, it can be widely used

glazing agent formula 3: acrylate UV curing glazing agent

acrylate UV curing glazing agent has been reduced from 70000 yuan/t, which is not too fast in the original experiment, to 35000 yuan/t. It has a fast curing speed. It is a 100% solvent-free and environmental pollution-free glazing agent. Its component is the acrylate monomer solution of acrylate prepolymer, and the formula contains photosensitizer, polymerization inhibitor, catalyst and other components. When in use, it is prepared on site, coated on the printing machine with a concave eye roller, irradiated with ultraviolet light tube, and cured instantly. Like polyurethane polish, the cured film of the polish has good acid and alkali resistance and organic solvent resistance

Polish formula 4: silicone Polish

107 silicone rubber: 10

tetrabutyl silicate: 3

dodecyl n-octyl tin: 0.5 ~ 1.5

silane crosslinker: 0.5 ~ 1.5

the above ratio uses toluene or anhydrous ethanol as solvent, and prepares a solution of 5 ~ 10% for concave coating roll or reverse roll coating, and then heating reaction, drying and curing

(II) dry composite coating method

the two-component polyurethane composite film is coated on the treated surface of BOPP. After heating and drying at 60 ~ 90 ℃, it is bonded with the printed substrate surface on the dry composite roller on the printed surface, and after bonding, it is cured in the curing room at about 60 ℃ for about 2 days. In this way, it can have good composite fastness and gloss. The ink used should be composite ink, but only surface printing. Because the composite ink has good adhesion with two-component polyurethane, its performance is reliable

(III) extrusion coating glazing method

the resin with low melting point and excellent transparency is used for extrusion coating on the printing surface to obtain good gloss, such as EVA or LDPE. The low melting temperature will not cause the ink to change color, decompose and fade due to high temperature

as far as I know, the above three methods have been implemented in some soft plastic packaging factories. For example, there is a soft packaging factory in Hangzhou, which pastes BOPP film after printing on the surface of milk film to improve gloss. □

reprinted from: data collection

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