DIAZO & DUAL CURE EMULSIONS

Technical Information

Instructions for use

TCL Emulsions should be handled in subdued daylight or preferably under yellow fluorescent or incandescent lighting at a maximum intensity of 60 Watts at a distance of not less than 2 metres. They must on no account be used in direct sunlight.
Sensitising:

TCL Emulsions are supplied as a two component product, consisting of a large bucket containing the emulsion and a smaller bottle containing the sensitiser.

Sensitising should be carried out by filling the smaller sensitiser bottle to approximately 50% of its capacity with clean water, replacing the lid and shaking until the sensitiser is dispersed. The solution thus formed is added to the contents of the emulsion container. The sensitiser bottle is rinsed out twice by filling to approximately 25% of its capacity, shaking and adding to the contents of the emulsion container.

Note: For course fabric or for a thicker, more viscous emulsion, mix the diazo with less water. However this causes the emulsion to coat thicker and may require an increase in exposure.

Note: For a thinner stencil dilute the emulsion. Add the normal quantity as explained above and then add one additional diazo bottle of water into the emulsion and stir well. The emulsion will then coat thinner and may require a decrease in exposure.

The emulsion is now stirred until the contents are fully homogeneous, this can be done with advantage by using a mechanical agitator. After sensitising, the emulsion should be left for a period of not less than 1 hour to allow bubbles to disperse, following this the emulsion is ready for use.
Screen Preparation:

Screens, new or used, must be degreased. We recommend TC6002 or TC6045 Mesh Preparation Compounds to prevent static, remove dust and eliminate pinholes & fish eyes, ensuring optimum stencil adhesion. The screens should then be well washed and dried using a fan heater to assist.

Screens should be coated in the normal manner, 1 or 2 coats of emulsion being applied to the underside of the screen and 1 or 2 coats on the top side, all wet on wet is recommended.

Note: It is permissible to use other coating schedules to produce stencils of greater or lesser thickness.
Coated screens should be dried in a near horizontal position in darkness or subdued lighting, care MUST be taken that dust does not settle on the screen surface.

Note: Drying may be assisted by the use of a fan heater/dryer, but the air temperature must not exceed 35 degree C.
Exposure:

Correct exposure is most important in obtaining results from TCL Emulsions. It is highly recommended that an exposure guide is used to determine optimum exposure, failing this a "stepwedge" should be carried out.

It is important that the positive be placed with its non emulsion side to the glass of the exposure frame and that the glass be well cleaned. It is also essential that intimate contact be achieved between the glass, positive and screen. This is best done by employing a vacuum frame but for an emergency a sheet of 0.25 inch plate glass with appropriate weighing may be employed.

Exposure depends on the nature of the light source condition and the distance between screen and light source. Once it has been determined it should not be necessary to vary the exposure unless changes to the relative positions of the light to the screen have been changed. Light source condition should be checked at regular intervals using an appropriate exposure guide.
Development:

Development should be carried out by first wetting the screen with cold or warm water, very hot water should not be used, after a few minutes the unexposed emulsion should be removed using a gentle waterspray. High pressure washing should not be used.

Development is continued until all traces of unexposed material are removed and thus the wash water is completely clean. Immediately after development, remove surplus water with a clean chamois leather or sponge, do not use lint or fibre containing cloths.
Drying

Lay the screen in a near horizontal position and dry using a fan heater/dryer at an air temperature of not more than 40 degree C.

Spotting out of small defects may be carried out by using sensitised TCL Emulsion followed by another re-exposure. For extended runs these products may be increased in durability by post hardening although this process will have an adverse effect on its reclamation properties. After drying the screen is ready for use.
Note: As a guide the following exposure times are quoted:
LIGHTSOURCE DISTANCE EXPOSURE DISTANCE EXPOSURE
  Diazo Emulsions Dual Cure Emulsions
50 Amp Open Carbon Arc 1 Metre 500-800 Secs    
HPR125 Watt Mercury Vapour Lamp 0.5 Metre 200-400 Secs    
1Kw Metal Halide 1 Metre 300-400 Secs 1 Metre 120-180 Secs
2Kw Metal Halide 1 Metre 150-210 Secs 1 Metre 110-150 Secs
3Kw Metal Halide 1 Metre 105-150 Secs 1 Metre 95-120 Secs
5Kw Metal Halide 1 Metre 80-100 Secs 1 Metre 70-85 Secs
Safety Information

The emulsions are not hazardous although it is advisable to wear rubber gloves when handling. TC 7110 or TC 7111 are available.

The sensitiser is acidic, care should be taken to avoid skin contact. If skin contact occurs then wash immediately with copious quantities of warm water. If irritation persists seek medical advice.

The sensitiser causes yellow stains on the skin these are not harmfull and temporary in character.

In case of eye contact, wash with copious quantities of water, seek immediate medical assistance.

In case of ingestion, give milk or water, seek immediate medical assistance.

Consult the Health & Safety Sheet on this product before use.
Disclaimer

While the information in this data sheet is based on sound research and is believed to be correct, no liability for failure in use of this product can be accepted by Thanet Coatings Limited, as the conditions under which the product is used are beyond our control.
Packaging
DIAZO & DUALCURE Pack Size: 0.9 Kilo or 4.5 Kilo
  TC6000 TC6016 TC6026 TC6001 TC6042 TC6043 TC6048
  Diazo Diazo Diazo Diazo Dual Cure Dual Cure Dual Cure
  Emulsion Emulsion Emulsion Emulsion Emulsion Emulsion Emulsion
  No 2 No 5 No 6 No 9 No 12 No 14 No 16
Applications              
Textile              
Water Based   Outstanding Excellent   Outstanding Excellent Good
Plastisol Good Outstanding Good Excellent   Excellent Excellent
Graphics              
General Print Excellent   Excellent Excellent   Excellent Outstanding
Half Tones Excellent   Outstanding Fair   Excellent Outstanding
Resistance              
Solvent/UV Outstanding   Excellent Excellent   Excellent Outstanding
Water Based/UV     Excellent     Excellent Outstanding
Water/Solven     Excellent     Excellent Excellent
Water Based   Excellent Good   Outstanding Good Good
Properties              
Colour Violet Violet Green Violet Green Blue Blue
Coating Properties Outstanding Excellent Outstanding Excellent Outstanding Excellent Outstanding
Definition Excellent Excellent Outstanding Excellent Outstanding Outstanding Outstanding
Resolution Excellent< Good Excellent Excellent Excellent Excellent Outstanding
Decoatability Excellent Good Excellen Excellent Outstanding Outstanding Outstanding
Solids Content 27% 38% 34% 32% 40% 36% 40%
Exposure* 130 Secs 160 Secs 140 Secs 130 Secs 120 Secs 110 Secs 75 Secs
Mesh Size 120 62 120 120 43 120 120
Stencil Build** 6 microns 20 microns 8 microns 8 microns 18 microns 10 microns 10 microns
Viscosity*** 7000 7000 7000 8000 6000 5000 5000
Approx Life:              
Sensitised Emul 3 months 3 months 3 months 3 months 1 month 1 month 1 month
Coated Screen 2 months 2 months 2 months 2 months 1 month> 1 month 1 month
               
* 5kw metal halide @ 1.2 metre
** 2+2 coats on mesh above
*** poise @ 25°C unsensitised