MEK ResistanceOne-300 watt per inch Hg lamp

0

10

20

30

40

50

60

70

0 30 60 90 120 150

Line Speed (ft/min)

MEK

dou

ble

rubs

UV Curable Overprint Varnish for Paper

Starting Formulation

Ingredient WT %CN120A75(Epoxy Acrylate) 62.40SR306 (TPGDA) 29.40Esacure® KIP100F 1.80Benzophenone 2.80Dibutylaminoethanol 2.70DC-1901 .90

Viscosity @ 25°C (cps) 690Density (lbs\gal) 9.12Color (APHA) 100

Suppliers1 Dow Corning Corp.

The formulation is based on CN120, epoxy diacrylateoligomer, and SR306, tripropylene glycol diacrylatemonomer. A surfactant was incorporated to improveboth wetting and slip properties.

Typical cured film properties of this formulationwere obtained from films applied via an offsetproving press to inked paper stock. The coatingwas applies at 3.5 lbs/ream (ft2) and cured at 90 ft/min with one 300 watt per inch medium pressuremercury vapor lamp.

Figure 1 gives MEK resistance (double rubs) as afunction of line speed. MEK double rub resistancemeasures the total coating cross link density at agiven line speed. SR306, difunctional acrylate,provides minimal cross linking.

Cured Properties

Slip Angle 22°Coefficient of Friction (static) 0.36MEK Resistance (Double Rubs) 16Gloss 60° 88

As a result MEK resistance drops at faster linespeeds. Addition of a trifunctional acrylate, SR454,will significantly increase MEK resistance and curespeeds.

Figure 1

Figure 2 gives coefficient of friction (COF) versesline speed data. COF is a measure of the coatingssurface slip. Coating surface cure relates directlyto COF. Increasing the cross link density by addingSR454 and/or photinitiator will maintain COF at fasterline speeds. COF is further decreased by increasingthe level of DC-190 silicon slip aid.

APPLICATION BULLETIN

Oaklands Corporate Center, 502 Thomas Jones Way, Exton, PA 19341Telephone 610-363-4100 Toll Free 800-345-8247 Fax 610-594-0252

4020 06/05

Gloss (60 °)One-300 watt per inch Hg lamp

75

80

85

90

95

100

0 30 60 90 120

Line Speed (ft/min)

Glo

ssCoefficient of Friction

One-300 watt per inch Hg lamp

00.05

0.10.15

0.20.25

0.30.35

0.4

0 30 60 90 120

Line Speed (ft/min)

CO

F (s

tatic

)

Figure 2

Figure 3

Figure 3 gives Gloss (60°) verses line speed. Glossis a measure of the reflective qualities imparted bythe coating. Coating thickness, smoothness, andrefractive index all influence gloss. Improving theflow and leveling of the coating will increase gloss.Lowering the formulation viscosity and/oroptimizing the additives improve flow and leveling.

Blending ProceduresAll formulation ingredients are completelycompatible and soluble with one another. Firstdissolve the benzophenone in SR306 using a low shearmixing blade. When the benzophenone is dissolved,slowly add the CN120A75. To facilitate pouring, theCN120A75 may be warmed prior to incorporation.(Avoid gelation during warming step, do not exceed140 F.) Once a homogeneous mixture is obtained,incorporate remaining ingredients. Continue mixingwhile allowing the lend to cool. Enhanced stability isobtained by discharging the formulation below 100°F.

Storage and HandlingUV curable formulations should be stored andhandled in amber glass, baked phenolic lined, stain-less steel, or polyethylene lined containers. A headspace should be present in any storage container tosupport the oxygen requirements of the inhibitor.This material should be stored in the dark and attemperatures not exceeding 90°F.

Safety PrecautionsMaterials in this formulation can cause eye and skinirritation, and have potential to cause skin sensitizationin susceptible individuals. Proper industrial hygienepractices should be utilized. Consult the appropriateMaterial Safety Data Sheet before using any chemicallisted in this bulletin.

The information in this bulletin is believed to be accurate but all recommendations are made without warranty, since the conditions of use are beyond SARTOMER Company’s control. The listed properties areillustrative only, and not product specifications. SARTOMER Company disclaims any liability in connection with the use of the information, and does not warrant against infringement by reason of the use of its

products in combination with other material or in any process.