Release Papers: New Trends Are Driving the Market
- Published: June 01, 2000, By Bob Tardiff
Release papers provide the base for a pressure-sensitive label system that runs the gamut from generic mailing labels to high-specification applications such as food nutrition labels and self-adhesive postage stamps. As such, the requirements for protective layers or backing papers must match performance characteristics with the specific p-s application, be it generic or specialized.
The ability of release paper manufacturers to meet customer requirements by tailoring papers to unique specifications is being influenced by four emerging trends in the industry.
Basis Weights and Calipers
- Trend 1: Lower basis weights and calipers in roll label, super-calendered, kraft release liners.
Electronic data processing-generated labels are one product category that seems to benefit quite a bit from the lighter weight caliper. Trials for other applications will get further consideration, with cost and speed of market acceptance being the driving factors.
The switch to a lower basis weight often requires rebuilding dies, and in some cases reconfiguring some aspects of a press. Forward-thinking converters and printers will undertake the hardware investment to run the lower basis weights because of their focus on long-term return on investment.
The Layflat Factor
- Trend 2: Better layflat of release liners for p-s laminate performance in graphite composites and laser copiers.
- Engineered runnability is the overriding concern here. The impact of runnability on production performance at the customer end dictates the necessity of having a release paper that consistently performs without curling or welting, regardless of the demands of the production environment. To this end, three options are available: clay-coated liners, low-density liner products, and machine-finished kraft liner.
Clay-coated liners provide a base that is a good silicone coating substrate and does not curl after lamination to paper or film facestocks. They also remain dimensionally stable when used as a carrier sheet for graphite composites. In addition, some clay-coated, two-sided liners are being used to provide a printable surface for conventional and laser printing on the nonsilicone side.
Low-density liner (LDL) products combine the surface holdout feature of conventional super-calendered kraft with lower internal-fiber density. The resulting product is lower in basis weight at a standard caliper and is also much less subject to curl after laminating to film or paper facestocks. While there is not a wide array of LDL products currently available, the market seems to hold promise from a growth standpoint. The less-demanding die-cutting requirements for the electronic data processing market hold the most promise for LDL products.
Machine-finished kraft liner products generally have a reduced holdout for silicone and thus are expensive to coat, but they have found acceptance in laser copier/printer applications, in which the rougher or "toothier" backside allows the laminated label sandwich to feed more consistently through the many paper rollers in these complicated machines. The resurgence of demand for machine-finished is tied to the creation of "sandwiches" that can be imaged in ink jet, laser, electrostatic, or thermal printing machines without curling or misfeeding.
While commercial digital imaging has yet to reach the projections put forth when the technology was launched, it is a growth sector that looks more robust than anticipated.
Die-Cutting Solutions
Trend 3: HDL (high-density liner) release liners and glassine liners are finding a niche where the die-cutting of film facestocks requires a very dense, hard mandrel for clean, crisp label edges and high-speed dispensing.Some die-cutters insist they are unable to die-cut film facestocks adequately without a hard mandrel to die-cut against. The hardest paper mandrel is glassine, a dense, almost transparent product produced on specialized paper and converting equipment. While glassine has proven itself in Europe, it has not been widely available or accepted in the US. The dilemma has moved some domestic converters to import glassine from Europe.
A more logistically manageable solution is the move by some US paper manufacturers to retrofit calender units with the capability to produce HDL in order to mimic glassine. However, it is questionable at this time whether the demand is high enough and sustainable enough to warrant the capital investment required to do this retrofit.
Adding On to Subtract Costs
- Trend 4: An increasing number of label printers are installing ultraviolet silicone curing units, and even adhesive and laminating equipment, on label printing presses in an effort to reduce p-s laminate costs.
While this trend toward establishing a turnkey-type operation does not directly affect liner manufacturers, it has the potential to negatively impact converters and laminators.
For example, a prototype unit currently in trials combines an 18-in., ten-color press with a silicone coating and curing unit, an adhesive applicator, and a laminating nip prior to the printing units. With potential cost savings of about 25%, printers can gain a good deal of pricing leverage against competitors that do not have the same in-house capabilities.
This turnkey trend is just peeking over the horizon. Traditional converters and laminators will stand to lose business in all-purpose adhesive systems, because once the technology is perfected, it will be a logical retrofit for every label printer in the country.
However, there will always be a very large niche for products that use specialized adhesives. Printers that handle these products will not be able to bring these processes in-house because of the technical challenges of marrying the adhesive and silicone release technologies.
- Trend 4: An increasing number of label printers are installing ultraviolet silicone curing units, and even adhesive and laminating equipment, on label printing presses in an effort to reduce p-s laminate costs.
