Awadhoot Shendye Western Michigan University LITHO VARNISH MAKING

Transcription

1 Awadhoot Shendye Western Michigan University LITHO VARNISH MAKING

2 LAB SCALE ASSEMBLY COMPONENTS

3 OTHER EQUIPMENTS Weighing balance to weight material Thermometer- To measure temperature Hot plate- To supply heat to reaction Stirrer For mixing Wax Used on joints of glass Tubs- For water circulation Filter To filter varnish

4 KETTLE

5 COMPLETE ASSEMBLY

6 RAW MATERIAL Resins- Grinding, extender Oils- linseed, soy, tung (china wood) Petroleum distillate Antioxidant BHT,TBHQ Gelling agent Alkyd

7 SF GRINDING VARNISH FORMULA (GENERAL) Material Weight % Resin Grinding 52.5 linseed oil 23 Petroleum distillate 18 BHT 20 % solution 2 Alkyd resin 4.5 Total 100

8 SF GEL VARNISH FORMULA ( GENERAL) Material Weight % Resin Extender linseed oil 27 Petroleum distillate 25 BHT 20 % solution 2 Gelling agent 0.75 Total 100

9 TUNG OIL FORMULA Material Weight % Resin Extended 40 linseed oil 33 Tung oil 25 BHT 20 % solution 2 Total 100

10 HEATSET & COLDSET If heatset & coldset inks are made by dry powder pigment then generally only one varnish is used. But heatset & coldset is high volume low profit margin business & ink manufacturing by powdered pigment is expensive than flush pigment so generally these inks are made by flush pigments. If coldset & heatset inks are made by flush pigment then no varnish is required. But sometimes around 5% varnish is added while blending.

11 COLDSET GRINDING VARNISH Material Weight % Resin 39 Soy oil 15 Petroleum distillate 42 BHT 4 Total 100

12 HEATSET GRINDING Material Weight % Resin 43 Soy oil 24 Petroleum distillate C 31 BHT 2 Total 100 Melting point of resin, used in heatset varnish should be less than, temp of dryer(heater) on printing m/c

13 NOTE Formula shown in this presentation is just guideline actual amount of resin can change by 10-15% because amount is depend on properties of resin such as molecular weight, target viscosity of varnish & ink, required tack of varnish & corresponding ink along with varnish amount in ink. Based on required properties of varnish- ink & raw material properties,its amount vary in formula

14 VARNISH MAKING PROCEDURE 1) Make assembly as shown in previous pictures and test all functions are in working condition. 2) Add petroleum distillate, oil, BHT in kettle 3) Start stirrer and heat. 4) Once temp reaches around C (or melting point of resin) start adding resin in small batches.

15 VARNISH MAKING PROCEDURE 5) Allow to dissolve all resin and raise temp to C 6) In case of gelling varnish add gelling agent by dissolving it in petroleum distillate. 7) Maintain temp to C for around 30 to 40 min. 8) Bring temp to around C. 9) Filter varnish.

16 VARNISH TESTING 1) Viscosity Laray viscometer is used with Lehman chart method at 25 0 C. Rheometer with cone (1 0 )-plate assembly is also used. 2) Tack Measured at 800 or 1200 rpm after 1 min at around 32 0 C 3) Hexane no. It is amount of hexane required, subtract 10 from measured value, to dissolve 10 gram varnish.

17 VARNISH TESTING Color- By Gardner scale, spectro & clarity by visual inspection Flow Flow in cm on or 45 0 flow plate after 10 min. Cloud point- It is amount of petroleum distillate required to make cloudy solution of 10 gram varnish.

18 WHAT IS CLOUD POINT & WHY TO MEASURE IT? Ans->The temperature at which a heated mixture of varnish resin and a selected mineral oil clouds on cooling is a useful index of the relative solubility of the resin. Deviations in cloud point can lead to sedimentation in the varnish, differences in drying speed, loss of gloss and tack stability.

19 TEST METHODS ASTM D (2005)e1 -Standard Practices for Preparation of Oil-Based Ink Resin Solutions ASTM D (2004)- Standard Practice for Laboratory Preparation of Gelled Vehicles Using a Resin Kettle ASTM D154-85(2009) -Standard Guide for Testing Varnishes ASTM D Standard Test Method for Viscosity of Resin Solutions

20 TEST METHODS ASTM D (2006) Standard Test Methods for Nonvolatile Content of Varnishes ASTMD E01 Test Methods for Determining the Compatibility of Resin/Solvent Mixtures by Precipitation Temperature (Cloud Point) ASTMD E01 Test Methods for Determining the Compatibility of Resin/Solvent Mixtures by Precipitation Temperature (Cloud Point)

21 TEST METHODS ASTMD R05 Test Method for Viscosity and Yield of Vehicles and Varnishes by the Duke Viscometer ASTMD Guide for Testing Printing Ink Vehicles and Components. ASTMD Test Method for Viscoelastic Properties of Paste Ink Vehicle Using an Oscillatory Rheometer.

22 GILSONITE VARNISH Material Weight % Gilsonite selects 36 Soy oil 10 Petroleum distillate 54 Total 100 Gilsonite varnish is added only in black ink.