Advanced Coating Technology for Faster, Better Processing
Since 1980, DYMAX has pioneered adhesive curing technologies which dramatically reduce assembly costs and increase the profit potential of manufacturing processes. Chemistries which slash curing times from days to minutes and hours to seconds, provide productivity increases or 90% or more for automotive, medical electronic and general industrial assembly operations.

Feature	Benefits
Faster production	Faster customer response Reduced order to shipment time Greater productivity
Cure on demand	Instant light cure “locks out” airborne contamination Cure occurs when and where you want it
One part resin	Consistent viscosity means fewer rejects; less scrap Less chance for air entrapment; improved yield Reduced purge and resin waste disposal Eliminates the need for metering & mixing equipment
Small footprint	Frees factory space for more production
Less labour	Reduced Costs
No mercury No isocyanates	Fewer health and safety issues Fewer disposal issues and costs

Considerations for Selecting a Coating

1) Viscosity
How thick a coating is necessary? Protective decorative coatings are clear and usually thin. Dome coatings have curved domes, which optically magnify and enhance the appearance of a label. Higher viscosity, thicker resins generally produce taller domes.

2) Substrate Flexibility
Flexible substrates, like thin polyester labels, paper, or soft plastics, may require careful selection of coating and enhanced curing equipment. Flexible substrates may bow or warp when thick coatings cure. Soft coatings shrink less and are designed to reduce or eliminate warpage during cure. Rigid substrates don't bend when stressed; so, they can be coated with all of the products.

3) Substrate Adhesion
Individual formulations may have excellent adhesion to some inks (or substrates) and little adhesion to others. The right coating should have good adhesion to the substrate. Adhesion should be tested after product lifetime testing, as well as after cure. Inks and substrates from second source suppliers may improve or worsen adhesion. Some plastics require surface treatment to enhance adhesion. DYMAX 4-20586 responds well to surface treatment.

4) Hardness
Both soft and hard coatings can be scratch resistant. Hard coatings resist scratching because of their hardness. Soft coatings resist scratching because they momentarily dent and then spring back when the scratching object is withdrawn. Hard coatings are measured on the D-hardness scale. Soft coatings are measured on the A-hardness scale. On both scales, higher numbers imply harder coatings.

5) Environmental Durability
Coatings should be lifetime tested on your product. Some properties, like UV weatherability, provide a relative guideline to distinguish endurance of clarity and durability among the available products offered.

Industrial Dome and Decorative Coatings Selector Guide

Product	Applications	Characteristics	Hardness Durometer (1)	Viscosity (cP)	Relative Weatherability
Dome Coatings
4-20564 82Kb	Small Decals (Up to .25" × .5")	Hard scratch resistant surface; resists yellowing	D-75	6,000	Limited outdoor (3)
4-20435 81Kb	Pen tops, small labels (to .25" × .5")	Hard scratch resistant surface; resists yellowing	D-75	3,400	Excellent Indoor
4-20577 88Kb	Medium Decals (Up to 1" × 3")	Surface springs back from dents; difficult to scratch; resist yellowing	A-70	1,500	Limited outdoor (3)
4-20429 127Kb	Large Decals (Up to 1" × 8")	Surface springs back from dents; resists yellowing	A-70	1,500	Good indoor
4-20586 17Kb	Plastic and metal name badges	Cures with lowest intensity lamp	D-60	1,200	Indoor only
4-20508 83Kb	Plastic and metal name badges	Hard scratch resistant surface; resists yellowing	D-80	800	Excellent indoor
4-20630 88Kb	Medium decals (up to 1" × 2")	Surface springs back from dents; difficult to scratch; resists yellowing	A-75	800	Limited outdoor (3)
4-20645 79Kb	Small decals and objects	UV curable "rubber feet"; clear anti-skid coating	A-75	600	Good indoor
Decorative Coatings
4-20624 (2) (68Kb)	Matte finish, low gloss, low viscosity	Low gloss is a typical of UV coatings	D-85	800	Good indoor
4-20638	High gloss	High hard gloss coating	D-80	100	Limited outdoor (3)

Dome Coating Applications

DYMAX 4-20564 is used to continuously coat logo decals	DYMAX 4-20508 with a high gloss finish is used to decoratively coat a key chain
DYMAX 4-20577 is used to coat a medium size decal	DYMAX 4-20435 resin is used to seal a label in a pen cap

UV Lamp Selection is Critical to a Successful Process
The UV curing lamp used affects appearance and feel of a coating. Although the highest power lamp will cure the coating fastest and produce the smoothest, slickest surface, it may also warp, yellow or melt the object being coated (and it will cost the most). It is always best to test an application with several light sources. Lifetime tests sometimes favor one lamp system over another.

DYMAX Has What You Need for Safe UV Processing and Process Control
DYMAX equipment is shielded so that operators and others are not exposed to UV light. DYMAX also supplies protective goggles and face shields. The DYMAX ACCU-CAL™ 30 radiometer, an essential tool for measurement and control of the light curing process, is also available.

Match a DYMAX Curing System to the coatings and application for the best process, every time!

Applications	Recommended Lamps	Considerations
Small decals and pen tops on rigid substrates	5000-PC or conveyor with Fusion D-bulb
Large decals on rigid substrates	5000-PC or 2000-PC followed by 5000-EC	Second option manages heat
Small decals on flexible substrates	2000-PC
Medium and large decals on flexible substrates	2000-PC or black light followed by brief exposure to shortwave light or a high power lamp	Second option manages heat and possible label warpage

Shielded Light Curing Chambers

Conveyorised Curing Systems

Process Tips for Successful Coating
Avoid resin running over the edge of the label or object
1) Resin is deposited at the center of the label or object and flows towards the edges. Sharp edges tend to repel overflow. Irregular edges encourage overflow. Thick label stock tends to maintain its edge and minimise overflow.
2) Label backing can minimise or encourage overflow. If the backing material "wets" more readily than the label surface, it tends to draw the coating over. Using a backing that repels the resin encourages it to remain on the label.
3) Use an X-Y dispenser to dispense a pattern instead o a single drop on noncircular objects. Pattern dispensing lets the resin flow to all the edges at the same time rather than all running to one edge where it can flow over before reaching the remaining edges.
4) Level the dispenser, transfer and curing stations.

Avoid air bubbles in the coating
1) Purchase products in air free packages (syringes or cartridges).
2) Dispense directly from the shipping container. If resin must be transferred from one container to another, then transfer the container at the end of the last shift.
3) Use low pressure dispensing. Since pressure drops can pull air into the dispensing line, dispense with the lowest pressure possible.
4) Use the shortest possible lines between the container and the dispensing needle.
5) Pass the uncured (liquid) coating underneath a natural gas flame to burst surface bubbles.
6) Process by continuous dispensing and purge tip when restarting line. Whenever fluid flow stops completely, the resin may retract. When resin retracks it can pull air into the line or dispensing tip. The air can create bubbles before it is purged from the line.

Eliminate warpage during cure
1) Some thermoplastics curl or warp when hot. Use a thermoplastic with a higher melting point or reinforcement to solve this problem. Using a thicker substrate may also eliminate warpage.
2) To eliminate curl when doming on thin polyester labels try precuring with a "black" light. The "black" light should have a maximum intensity at 365 nm. Regular purple colored bulbs or germicidal bulbs will not work. The precuring polymerises the coating below the coating's surface. A second lamp is then used to cure the surface to a scratch resistant state. As the label gets larger, softer resins are necessary to prevent warpage.
3) Use of thicker polyester stock to stiffer backing sheets minimizes curl of domed decals.

December 2002
Version 1.0