Surface Treating Glossary

Provided below is a glossary of surface treating terms. For answers to more detailed questions see our Surface Treating FAQ.

Additive/Additive Loads

Any substance that is added to another substance. Usually a material added in minor amounts to alter the properties of a resin or compound. The additives that concern surface treatment are slip, anti-block, colorants, chill roll release, etc.
 

Bare Roll

The Bare-Roll design eliminates the need for a dielectric covering on the treater roll. This saves the cost of a spare dielectric roll. The Bare-Roll also prevents the loss of film and production time due to roll covering burn out. The system treats any web, including: plastic, foil, metalized film or paper. The patented airflow design aids in electrode temperature stability and provides ozone removal for an ozone safe work area. The high-efficiency ceramic electrodes are long-lasting and provide higher treatment levels.
 

Coating

Coating is a process whereby a coating is applied to a substrate. The coating can be solvent based, water based, UV curable or electron beam curable. Sometimes coating can mean extrusion coating whereby a substrate is coated with a molten polyolefin.
 

Coating/Laminating

Coating is accomplished by the use of numerous types of roll coating methods and slot die coating techniques. Laminating consists of combining and bonding diverse substrates with either wet or dry adhesives, thermally or by the use of hot-melt adhesives. Substrates most commonly used include papers, film materials (nylon, cellophane, polyester, polyethylene, polypropylene, etc.), aluminum or steel foils, non woven, textiles, fabrics and carbon fibers.
 

Corona

Corona treatment is a common method used to increase the surface energy of plastic by means of a high voltage electrical discharge, thus improving its wettability and adhesion characteristics for printing and laminating. Although there are numerous theories explaining the principles behind the process of corona treating, the most commonly accepted theory appears to be the theory of high speed oxidation. Basically, this theory states that the energy of the corona breaks the molecular bonds on the surface of the non-polar substrate. The broken bonds then recombine with the free radicals in the corona environment to form additional polar groups on the film surface. These polar groups have a strong chemical affinity to the polar inks and adhesives, which results in improved adhesion. Similarly, the polar surface results in an increased surface energy which correlates with improved wettability.
 

Covered Roll

The Covered-Roll treater system is equipped with covered ground rolls and segmented or tube stainless steel electrodes. The electrode assembly configuration and method of ozone extraction and electrode cooling assures that the inside of the station is ozone-free. This permits painted steel frame and enclosure-type construction with no risk of corrosion. The cooling system also reduces the temperature of the electrodes which, in turn, reduces the reflected heat into the web and ground roll. The highly efficient system of electrode cooling prevents any warping or distortion of the stainless steel electrode segments.
 

Dynes/cm or Newtons/meter

Dynes/cm or Newtons/meter is the unit of force in the centimeter-gram-second absolute system, the force which imparts an acceleration of 1 centimeter per second per second to a body having a mass of 1 gram. Symbol, dyne. In SI units, one dyne = 10 -5 newton. To convert from to Multiply by dyne (dyn) newton (N) 1.0 E-05.
 

Dyne Solution

Dyne solutions have been used to measure wetting and predict adhesive potential of plastics and coated paperboard. This method is widely used to test the treatment level of plastic films intended for printing, laminating, and coating. Test results are based on how varying surface tension solutions react when applied to a non-absorptive surface: If a given solution wets the surface, its dyne level is lower than the substrate's; if, instead, it rapidly forms beads, its dyne level exceeds that of the substrate. This method offers adequate precision and replicability for most capability studies, materials research, and process control.
 

Electrode / Dielectric / Ground Roll

The corona treating system in its simplest form can be portrayed as a capacitor. Voltage is applied to the top plate which, in the case of a corona treating system, would be the electrode. The dielectric portion of the capacitor would be made up of some type of roll covering, air and substrate in the corona treating system. The final component, or bottom plate, would take the form of an electrically grounded roll.
 

Extrusion

Extrusion is the process of introducing plastic resin pellets into an extruder then raising the temperature of the resin to its melting point and pumping the melted resin through a die to produce plastic film, sheet or a blown film.
 

Flame

A flame plasma is formed when a flammable gas and atmospheric air are combined and combusted to form an intense blue flame. The surface of materials are made polar as species in the flame plasma affect the electron distribution and density on the surface. This polarization is made through oxidation. In addition, functional groups are deposited on the surface.
 

Functionalization

Surface functionalization introduces chemical functional groups to a surface. This way, functional materials can be designed from substrates with standard bulk material properties. Prominent examples can be found in semiconductor industry and biomaterial research. In both cases, plasma processing technologies were successfully employed.
 

kVA vs kW:

kVA is kilovolt-ampere; kilovolt-amperes and kW is a unit of power equal to 1000 watts.
 

Nip Roll

Pneumatically operated rubber covered roll that applies pressure to the substrate onto the ground roll.
 

 

Ozone

A colorless gaseous substance obtained (as by the silent discharge of electricity in oxygen) as an allotropic form of oxygen, containing three atoms in the molecule. It is a strong oxidizer, and probably exists in the air, though by he ordinary tests it is liable to be confused with certain other substances, as hydrogen dioxide, or certain oxides of nitrogen. It derives its name from its peculiar odor, which resembles that of weak chlorine. Ozone generators deliver high ozone concentration at minimal power levels. Ozone generators are used to advance adhesion in extrusion coating and laminating.

• Adding ozone to your process allows for lower extrudate temperatures and the use of lower temperature resins (Eves).
• Reduced air gaps reduce "neck-in", translating into greater productivity.
• Some companies have improved production speeds by as much as 50% by adding ozone to their process.
• Ozone can also enhance product value by improving bonding characteristics, heat sealabilty, color and odor.

Plasma - Atmospheric vs Vacuum

Both atmospheric and vacuum plasma treating process introduce an inert gas and apply a high voltage to the gas providing an enhanced treating process. While atmospheric plasma introduces this gas at atmospheric pressure, the vacuum process evacuates all air from a chamber and then introduces the gas. One advantage to atmospheric plasma treating is a continuous web of material can be treated. However, vacuum plasma only allows a batch of items to be treated which is limited by the size of the vacuum chamber.
 

Power Supply / Generator

The power supply accepts standard 50/60 Hz utility electrical power and converts it into single phase, higher frequency (nominally 10 to 30 kHz) power that is supplied to the corona treater station.
 

 

Surface Activation

Increase of energy and decrease of contact angle, usually correlates directly with improved bonding.
 

Universal Roll

The design contains a special coated roll which in combination with our unique ceramic electrode assembly treats consistently to high levels. The system treats any web including plastic, foil, metalized film or paper. The patented air-flow design provides enhanced treatment levels and creates unique ozone removal capabilities for a safe work area. High-efficiency rectangular ceramic electrodes provide highest treatment levels.
 

Watt Density

Watt Density is a measurement of the amount of energy being applied to the web. It is measured in Watts/ft²/minute. Watt density takes into account the amount of power being applied (watts), the time it is being applied (minute) and the amount of material it is being applied to (ft²).

Once the watt density is known to get a particular material to a certain dyne level, it can be used to predict the results if any of the parameters change such as line speed. Utilize our online watt density calculator for more details.
 

Wetting Tension

The object of surface treating is to improve the wettability of the surface, thereby improving the ability to bond to solvents, adhesives, coatings, and extrusion coating. In order for a surface to be properly wet by a liquid, the surface energy of the plastic must be higher than the surface tension of the liquid. Surface energy is measured in dynes per centimeter. This surface energy is the wetting tension.