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PolyCol Micro

Description:

POLYCOL MICRO is a presensitized SBQ-photopolymer emulsion for graphic printing with most ink systems including water-based inks. High resolution and very good mesh bridging combined with its wide exposure latitude make it suitable for fine detail and 4-color process printing. The fast exposure time is especially helpful in large format applications.

Pre-sensitized -- ready to use.

To achieve a good stencil, the mesh must be degreased with a commercial degreaser such as KIWO Degreaser 1:20 or PREGAN A9 and must be free of dirt, dust, ink residues and ghost images. Rinse the screen thoroughly using low water pressure to remove any degreaser remaining on the screen. A foaming degreaser such as KIWO DEGREASER 1:20 or PREGAN A9 helps to determine proper and complete rinsing. See KIWO DEGREASER 1:20 or PREGAN A9 technical data sheets for details.

POLYCOL MICRO has excellent coating properties on mesh counts of 40-470 threads per inch (16-185 threads per cm). For best printing results, the following coating techniques are recommended using a round edge coating trough:

40-86 tpi (16-34 tpcm): 1-1 wet-on-wet
110-156 tpi (40-60 tpcm): 2-2 wet-on-wet
195-305 tpi (77-120 tpcm): 2-2 wet-on-wet
330-470 tpi (130-185 tpcm): 2-3 wet-on-wet

Always start with 1 or 2 coats on the substrate side of the screen to fill the mesh openings; then finish with wet-on-wet coats on the squeegee side to build up the emulsion coating to the desired thickenss. The correct coating technique for your process must be determined through coating tests.

Contact KIWO for more specific coating techniques.

Dry the screen in complete darkness, or under safelight conditions, with the screen in horizontal position with the substrate side down. Temperature, relative humidity and airflow affect the drying time. The screen must be dried thoroughly before exposing to achieve highest resistance to ink and ink cleaners. A temperature of 86°-104°F (30°-4°C) at a relative humidity of 30% -50% and moderate airflow are optimum conditions. Drying at room temperature and in uncontrolled conditions may lead to inconsistent results and varying screen resistance.

Expose with ultra-violet light at a wavelength of 320 – 380 nm. A metal halide lamp provides the best results. Due to the many variables that determine the actual exposure time, accurate exposure times cannot be given. The following examples are offered as a guide only:

Lamp: 5000 Watt metal halide at 40" (1m) distance.

156/62 tpi (60/62 tpcm) yellow mesh, coating technique 2-2.
Exposure time: approximately 60 seconds.

305/34 tpi (120/34 tpcm) yellow mesh, coating technique 2-2.
Exposure time: approximately 30 seconds.

The correct exposure time for your equipment and mesh selection, must be determined through exposure tests using a step exposure or and exposure calculator such as the KIWO STEP WEDGE EXPOSURE film or the KIWO EXPOSURE CALCULATOR films.

Under-exposed screens feel slimy on the squeegee side during developing. At correct exposure time, the screen is not slimy. Overexposure leads to loss of detail. Correctly exposed screens will withstand high tap water pressure during washout.

Contact KIWO if you have further questions regarding exposure time.

Develop the screen using full tap water and a medium spray pattern. Adjust the water temperature to lukewarm or slightly colder. Rinse thoroughly from both sides of the screen. Vacuum off any excess water or blot it off with newsprint paper. This will avoid runs or scum from under-exposure in the open areas.

Post-exposing the screen after developing and drying can be very effective. Post exposure times should be 1-2 times the original exposure time.

The emulsion can be chemically post-hardened using HARDENER AWR or HARDENER HP to improve water resistance. HARDENER HP improves the resistance, but the emulsion remains reclaimable. HARDENER AWR results in a permanent stencil with outstanding resistance. See HARDENER AWR or HARDENER HP Technical Data Sheets for details.

When printing with solvent based inks, retouching, blocking out can be done with KIWO TOUCH-UP and KIWO BLOCKOUT. For water resistance stencil, block out and retouch with KIWO BLOCKOUT WR/MV or use POLYCOL MICRO (dry thoroughly and re-expose completely prior to using HARDENER AWR or HARDENER HP). See KIWO TOUCH-UP, KIWO BLOCKOUT, and KIWO BLOCKOUT WR/MV Technical Data Sheets for details.

POLYCOL MICRO can be decoated with emulsion removers such as KIWO STENCIL REMOVER. Before decoating, ensure the screen is completely cleaned of ink or ink cleaning chemical residues. If water beads up on the stencil, degrease the screen prior to decoating. See the KIWO STENCIL REMOVER Technical Data Sheet for details. If the screen was chemically hardened with HARDENER AWR, reclaiming is no longer possible.

When under-exposed, the emulsion can cause emulsion haze after reclaiming. To remove haze, use KIWO HAZE REMOVER or PREGAN PASTE. Use the haze removing products with the KIWO INK WASH and haze remover activator or KIWO ULTIMATE INK WASH. These products are also very effective at removing ink haze. See separate Technical Data Sheets for these additional products for more details.

Viscosity: approx.: 10,000 mPas
Solids Content: approx.: 33%
Color: blue
Storage: 1 year at 68°F/20°C
Potlife: 1 year at 68°F/20°C
recoated screens: 8 weeks in complete darkness at 68°F/20°C
Freezing: protect against freezing
VOC: none
TLV: n/a
HMIS rating: Health – 1
Flammability – 0
Reactivity – 0

1 Quart, 1 US Gallon, 5 US Gallons, 32 US Gallon Drum.

For additional product information, please visit www.kiwo.com or call PCS at (919) 266-4463.

Thank you for choosing KIWO.

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