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Huayu Automation HY-230 Two Colors Automatic Screen Printing Machine for Polypropylene Centrifuge Tubes
HY-230 Printing and Capping Machine set is specially designed for printing of centrifuge tubes with flat caps.
Includes: Feeding, Flame Treating, Ionic Wind Dedusting, Magnetic Motor, Printing, UV Curing System, Capping, Discharging.
Details: http://www.oncemachinery.com/ONCE-Tubes-Screen-Printing-Machine/OS-230.html
Polypropylene Centrifuge Tubes Estimated Dimensions:
50ml centrifuge tubes estimated diameter*length 29mm*115mm
15ml centrifuge tubes estimated diameter*length 17mm*118mm
How to screen PE and PP tubes or bottles with UV curing ink?
The surface printing of the tube/bottle belongs to the container printing, which can be completed with a curved screen printing machine. For the printing of tube/bottle processed with non-polar PE and PP materials, such as shampoo, shower gel, cosmetics, insecticides, medical etc., light curing inks are generally used, so the surface of PE and PP must be treated before screen printing. Only then can the ink be firmly attached to it. So, how to polarize PE and PP tube/bottle to achieve good inking effect?
Pre-press processing requirements and parameters of tube/bottle (plastic PE, PP, PET, etc.):
At present, the photocurable ink has not been directly used on untreated PE and PP bottles. Therefore, to print PE and PP bottles, the PE and PP must be polarized before printing, otherwise the UV ink cannot be firmly attached. So how to polarize?
There are many methods of polarization treatment. In PE, PP plastics, tube and bottle industries, most of the flame treatment methods are used. The result of this flame treatment is to use the flame to contain free radicals such as O, N0, OH, and NH. The surface oxygen of high polymer such as PE, PP is extracted, and then the surface oxidation is carried out according to the free radical mechanism, and some polar oxygen-containing groups are introduced to undergo chain scission reaction, which changes the polarization of non-polar PE and PP, and change the wettability of the surface, to ensure the fastness of the ink.
Light curing ink failure and handling suggestions:
1. No adhesion
①Recommendations for handling incompatible inks and substrates:
Illumination treatment: ultraviolet light with a wavelength of 170-200nm is selected to irradiate the surface of the substrate before screen printing;
Flame treatment: polarization treatment method for substrates with thickness greater than 0.6mm;
Corona treatment: Polarization treatment method of thin substrate or thin film;
Wrong ink selected: The adhesive resin in the ink does not match the material of the substrate.
②Recommendations for the treatment of substrate surface contamination:
Remove the dirt on the surface of the substrate;
Alcohol wipes plasticizers, release agents and other softeners on substrates;
Add special adhesion enhancer for ink.
2. During the overprinting process, the adhesion between the ink layers is poor
①Operation suggestions on the over-curing of the previous layer and blocking:
Reduce the degree of photocuring of the previous ink, as long as it reaches 70% curing, so that the UV ink surface has good wettability;
Add special interlayer adhesion enhancer to the ink.
②Excessive additives:
Control the amount of additives, reduce the additives by l/2;
Control UV curing parameters such as UV power, increase the speed of UV and so on.
3. Can not be cured or the surface is sticky
①Suggestion that the ink layer is too thick to cure:
Change the screen parameters, such as the use of plain weave or flattened screen, reduce the screen distance, and reduce the thickness of the photosensitive layer of the screen; increase the hardness of the rubber scraping >75° and sharp rubber scraping;
Increase printing speed, change scraping pressure and scraping angle, etc.;
Add a small amount of special thinner to properly reduce the viscosity of the ink;
Add curing enhancer (solidification) agent to the ink.
②Recommendations for insufficient UV lamp power (energy):
Wipe the UV lamp tube and lampshade to improve the reflection effect of UV light;
The aging of the UV lamp should be replaced, and the general UV lamp should be replaced after 1200 hours of service life;
Increase the power of the UV lamp tube per unit length to ensure 80-120W/cw;
After using the UV lamp for 25/100-30/100 hours, the lamp should be rotated 1/4 before use.
③ Reasons and suggestions for insufficient light solidity caused by black, white, yellow or a mixture of these colors:
Adjust light curing parameters, such as UV lamp power, to slow down the time over UV;
Add curing enhancer to the ink to speed up the reaction time of the ink;
Add appropriate varnish to the ink to make UV light easier to penetrate.
4. Low gloss
① The reason for the incomplete curing of the ink, the suggestions for the treatment are the same as "3";
②The ink must be fully stirred before use. If it is not evenly mixed, it will cause low gloss.
5. The ink becomes patchy after curing
① Insufficient curing of the ink film, the treatment suggestions are the same as "2" in "3";
②Due to uneven ink film, handling suggestions:
The rubber blade is not flat;
The tension of the screen and its uniformity are not good;
The heat generated during UV curing is concentrated, so the speed of the UV machine must be increased.
6. Screen printing ink appears small "fish eyes" on the substrate
①Incompatible ink and substrate. At this time, the surface performance of the substrate should be improved. The generation of air bubbles can be controlled by adding an appropriate amount of defoamer to the ink or the surface of the substrate can be wetted to improve the surface printing state.
② There is debris on the surface. At this time, the surface of the substrate must be cleaned, and it can be washed with absolute ethanol and other solvents to improve the affinity of the ink and the substrate.
In the process of using UV ink, we must pay attention to control the printability of the ink and the substrate, and control several factors of UV ink photocuring and ensure good polarization treatment of the surface of the PE and PP bottles, and the PE and PP plastic bottles. Screen printing will definitely achieve very good printing results!
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