Textile Engraving Chemical Of Rotary Printing
UNIVERSAL ENGRAVING EMULSION:
APPLICATION: For Machine coating as well as hand coating of Rotary Screens of all mesh
count for Textile Rotary Screen Printing.
PROPERTIES: Easy, very smooth and uniform coating layer Easy Development
COLOUR: MR-63 Red After.Polymerization: dark red
MR-64 Blue. After Polymerization: Grenish Blue
RESISTANCE: Chemically and Mechanically resistance to all Printing
Pastes After Polymerization For 2 Hrs. at 180° C
DIRECTION FOR USE: The emulsion will be well mixed with sensitizer One Day Prior to use & keep Ovemight at cool and dry place. In order to get Uniform & even Coating layer Take 1 Kg of Photo Emulsion MR-63.64 in a clean vessel & also take 50 ml. of sensitizer. Mix them together for sometime till the colour of Emulsion is changed to light uniform green. Viscosity of the Emulsion can be changed by adding DISTILLED WATER depending upon mesh of the screen & technique of coating - i.e. machine coating or hand coating. Filter this emulsion with bolting cloth & close the vessel for 1 hour in cool dark place so that all the air bubbles are disappeared.
In this method of Textile Printing Emulsion is applied automatically to screen in single action & one cycle of operation from top to bottom & it forms smooth adhesion between emulsion & screen so that practically no touching is required & pinholes hardly ever occur. Viscosity of the emulsion can be diluted by adding distilled water to suit the machine coating.
In this type of technique round rings are inserted on both sides of rings & it is placed on floor in upright position & after that emulsion is applied to screen at even speed by using circular rubber squeegee from bottom to top & put the screen in dryer. Depending upon the mesh of the screen additional 3 to 4 coats are required by repeating the above procedure.
Drying the screen
After applying the emulsion the screen is transferred to dryer & dried by heating air approximately 30° C. & drying it to a relative humidity at 40%. In case of hand coating, if you are coating the screen for 2nd & 3rd time, it is important that the first coat be thoroughly dried before the subsequent coat is applied. Moisture remains present in coated screen even when the screen feels dry to touch.
Exposing the Screen
Exposing is one of the most important factors in achieving fine image &
sharpness in Textile Printing. The important aspect is deciding exposing time which depends on mesh of the screen, thickness of coating, light source for Photography & image pattern. Photo Emulsion is extremely sensitive to ultraviolet light & takes little time for photography. If exposing machines are fitted with metal halide lamps or xenon lamps then exposing time of 2 to 4 minutes are sufficient. Thus time of exposing varies from 2 minutes to 7 minutes depending upon light sources & exposure should himself determine the time.
Developing the Screen
Immediately after exposure, the screen is taken for developing where it is immersed in water for 5 to 10 minutes. The lacquer not exposed is removed into tank with rubber foam thoroughly both from inside & outside the screen till the image comes out clearly. Use of spray gun is desirable for removal of excess lacquer left behind after developing in the tank. Open areas in the screen are checked under light on touching stand & closed by means of brush.
Polymerization - Curing by Heat
After the screen is developed & dried (at room temperature) it is kept in polymeriser (Heater) for curing. The temperature in the chamber should be 170° C. to 180° C. throughout & constant & screen should be kept for at least one & half hour which ensures complete resistance to
Textile Printing Chemicals.
It should be ensured that temperature is maintained throughout, in the chamber. Generally it happens that temperature in the chamber varies considerably between top & bottom. To eliminate this it is desirable to turn the screen after 45 minutes.
It should be observed that colour of the screen is uniform throughout from top to bottom after curing, otherwise screen is under-cured & creates problem. It is here that the screen acquires its final chemical & mechanical properties.
The last stage in the process of preparing the screen for printing is gluing of endring from both the side so that it can resist considerable amount of force during printing speed
OUTLET RESULT: This also Particulars of the Exposing & Developing are theResults of machine coating while using a metal halide lame Not in tube light.
STORAGE: NOT SENSITIZED 12 to 20 months (5. – 20. C)
SENSITIZED # 3 days when stored in cool dry place.
PACKING: Photo Emulsion available in 10. kgs carboys SENSITIZER supplied with emulsion in 500 gms.
Above given data in Salient features are the result of supplied sample and other details which is not published herein are subject to diff-event climatic condition and present or absent of require machine. Hence recommended to your to take own ideal Exposure & developing time.