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SAKATA INX (INDIA) LTD TECHNICAL TRAINING - OFFSET INKS 08.09.06 & 09.09.06

SAKATA INX (INDIA) LTD TECHNICAL TRAINING - OFFSET INKS 08.09.06 & 09.09.06 VENUE : UNITECH - I COUNTRY CLUB, GURGAON TOPIC Coatings, its applications, advantages & application process. PRESENTER : Mr. Bhupinder Singh

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SAKATA INX (INDIA) LTD TECHNICAL TRAINING - OFFSET INKS 08.09.06 & 09.09.06

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  1. SAKATA INX (INDIA) LTD TECHNICAL TRAINING - OFFSET INKS 08.09.06 & 09.09.06 VENUE : UNITECH - I COUNTRY CLUB, GURGAON TOPIC Coatings, its applications, advantages & application process. PRESENTER : Mr. Bhupinder Singh CO – PRESENTER :Mr. Rajesh Chauhan. EXPERT :Mr. TAKASHI KIMURA

  2. Coatings It is a thin protective layer applied to a surface to protect and improve its appearance.

  3. Need Of Coatings in Printing • Alone ink cannot act as barrier to physical and chemical abrasion. • To provide more sheen or gloss. • To provide better slip properties. • For fast turn around on press. • To provide special effects. • To give advanced packaging solution. • Therefore along with ink, coating are used to give desired final print or pack.

  4. High gloss or matt finish Barrier property (vapor/grease) Scuff resistance Water and chemical resistance Heat resistance Blocking resistance Seal ability ( Blister Packing) Deep freeze resistance Hot foil stamping Flexibility Glue ability Coating Characteristics

  5. Functions of CoatingsGloss Level • 70 % and above – High gloss • 55 to 70 % - Gloss • 30 to 40 % - Satin or Neutral • Below 20 % - Matte

  6. Functions of coatings -Scuff, rub and slip properties • COF or coefficient of friction – denotes slip characteristics • Number of rubs with fixed weight • Dry or wet • Temperature and humidity conditions

  7. Types Of Coatings • Oil Base Varnishes • Aqueous Varnishes • U V Varnishes • Solvent Base Varnishes

  8. Oil Base Coatings • Litho over print coatings are generally solutions of solid resins in vegetable drying oils. • It is nothing but a colorless ink. • Most economical way for providing gloss and scuff. • Maximum film weight can be applied is as low as 0.8 to 1.5 g.s.m.

  9. Does not offer instant drying and necessary to use spray powder which can cause characteristic rough feel. Gloss level and scuff resistance is lower in comparison to aqueous and U.V. Tendency to yellowish ness. Do have a distinctive odor on dried print Is the most inexpensive way to add gloss to a printed piece. Ideal means of “spot” varnishing at high speed. Greater flexibility in film and creates no problem during folding and creasing. Advantages Disadvantages

  10. Aqueous Coatings • Styrene-acrylic based resin systems • pH between 8.2 to 8.6 • Solid contents typically between 40 to 45 % • Viscosity • Tower coating – 35 to 60 seconds • Flexo/Gravure – 30 to 40 seconds • Dampener – 60 seconds • Duct/screen – 30 +/- 10 poise

  11. Instant drying. No spray powder and cleaner environment. Generally better than OPV in gloss and scuff. Dried coating is water white and odor less,suitable for food packaging. Can be used as primer for UV Coat. Spot varnish is difficult and possibility is only cutting blanket on non -image areas which is generally done for providing cut-outs for printing packing information on pack. Advantages Disadvantages

  12. U.V. Varnish • Is the blend of acrylates of low molecular weights which when energized by the use of powerful UV light photo-initiators within the coating, crosslink virtually instantaneously to form a dry, solid resin film. • Maximum film weight applied is 3 gsm.

  13. Produce ultimate gloss and film hardness and instant curing. Good product resistance. Fast turn around and no spray powder. Being solvent free, taint problems are reduced although it does have characteristic odor. Higher unit cost. Lesser film flexibility. Substrate and dried ink should have sufficient high surface energy to be UV receptive. Advantages Disadvantages

  14. Precaution in doing UV and Aqueous coatings Over lithographic inks • Avoid inks that contain surface lubricants (waxes) and high concentration of distillates (ultra quick setting inks). • Ensure the inks are dry in offline application. Allow at least two days minimum. • Avoid use of final pigments - rhodamine, reflex blue, purple and violet. • In offline application spray powder should be used minimum or coated powders.

  15. Conventional or oil based Water based UV Coating Absorption and Oxidation Absorption and evaporation Photo-Polymerization Drying Process

  16. Application Methods • Roller coating • Off-line • In-line • Ink duct • Dampener system • Flexo • Gravure • Screen

  17. Reference Chart Of Coatings

  18. Thank You

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