Pressure-Sensitive Adhesives: A Sticky Recycling Problem

What are pressure-sensitive adhesives?

Pressure-sensitive adhesives (PSA)—also known as "self-adhesives"—are the adhesives used for the peel-and-stick variety of labels, stamps, "sticky notes," tape, etc. that are so popular today. PSAs do not require any moisture to activate them, unlike moisture-activated adhesives still used for most envelope closures.

Why are pressure-sensitive adhesives a problem for recycling?

Most paper recycling systems today use water as the medium to transform recovered paper into "pulp," which is then transformed back into paper. PSAs do not dissolve in water, but rather fragment into smaller particles during the repulping process. These particles—known as "stickies"—deform under heat and pressure, making them difficult to screen or filter out of the pulp. Stickies can become lodged on papermaking equipment or even in the paper itself, often causing serious damage to both.

PSAs exact a considerable cost on the paper recycling industry—an estimated $700 million per year. (Tom Friberg, "Cost Impacts of Stickies," Progress in Paper Recycling, November 1996.) This estimate includes the direct costs to paper mills and the reduction in prices received by recovered paper collectors and processors due to PSA contamination.

Stickies that become lodged in paper also cause problems beyond the paper mill. By creating holes or weak spots in paper, stickies can cause paper rolls to tear on web printing presses. By sticking together pre-cut sheets of paper, stickies can cause paper to double-feed through printers and copiers, creating jams.

Why are pressure-sensitive adhesive products so widespread?

The performance advantages of and consumer preference for PSAs outweighed recycling concerns when they were first introduced. Paper recycling interests believed that technological developments in recycling equipment and improvements in the recyclability of PSA formulations would solve the problems created by PSAs. While paper recycling technologies to remove PSAs have improved, they are still far from perfect. Furthermore, equipment incorporating those technologies is very expensive, and most paper recycling mills still lack such equipment.

The U.S. Postal Service (USPS) is a major user of PSA-based products, accounting for about 14 percent of U.S. consumption. (The USPS’ use of PSA labels considerably exceeds their PSA stamp production). To demonstrate its concern about the recycling problems caused by pressure-sensitive adhesives, the USPS is leading a major, multi-disciplinary effort to develop a screenable or recyclable PSA. The USPS reports that its project participants are very close to formulating a universally recyclable PSA. However, the recycling problems with current PSA formulations persist.

Why should businesses be concerned about PSAs and recycling?

Some alternatives to using PSA products can save time and money. (See opposite side of this fact sheet.) Furthermore, excessive PSA contamination can mean the difference between whether or not a paper collector pays a business for its paper. For those businesses that are provided no charge/no payment paper collection service, excessive PSA

contamination can lead to the paper collector discontinuing the service, possibly resulting in higher disposal costs for the business.

What are the alternatives to using pressure-sensitive adhesive products?

There are alternatives to using PSA products. Most of these alternatives require little change in office business practices, and some even save time and money. The following table identifies some of the more common PSA products used in offices and their recycling-friendly alternative products and procedures.

For more information about reducing contaminants in recovered office paper, request the publication "Improving Recovered Paper Quality" from the Board’s business assistance program (see top of front page).

PSA Product	Alternative Product/Procedure
Address Labels (used on standard letter envelopes)	Print addresses directly on envelopes. Basic printers often have adjustable guides to accept envelopes. More sophisticated printers accept envelope "cartridges," which typically hold up to 50 envelopes for multiple print jobs. Most word processing software has an "envelope" paper size in the print menu for correctly placing addresses on envelopes before printing. Use glassine (cellulose) film window or filmless window envelopes, and print mailing addresses directly on the letter to show through the window. This technique eliminates the need to print addresses on envelopes altogether. Glassine film is recyclable, unlike plastic film typically used for window envelopes.
Address Labels (used on larger mailing envelopes)	Handprint addresses directly on large mailing envelopes. This eliminates the need for an address label altogether. Order a custom rubber stamp to print your return address.
"Sticky Notes"	Use scratch paper for notes and secure with paper clips. Most paper collectors and paper mills still treat sticky notes as contaminants for high-grade paper. Furthermore, sticky notes are usually colored, which make them incompatible for recycling with white paper. Fluorescent-colored sticky notes are particularly problematic for the recycling of white paper. From a recycling perspective, it is best to simply avoid the use of sticky notes. Paper clips, if not removed at the source, are easily removed in the paper recycling process.
Postage Stamps	Request and purchase moisture-activated postage stamps. Traditional moisture-activated postage stamps are still available, although more than 90 percent of the stamps the USPS produces are now the PSA type. Check post office vending machines or counters for moisture-activated stamps. If you can not find them locally, you can order them from the USPS’s toll-free stamp order line: 800-782-6724. Purchase a postal meter that prints postage directly on envelopes or that uses moisture-activated meter tape.
File Folder Index Labels	Handprint file subjects directly on index tabs, instead of using an index label. When recycling file folders with index labels, tear off the index tab.
Closure Tabs (for fliers, newsletters)	Avoid closures altogether, if possible. Sharply folding fliers and newsletters is often sufficient to send them safely and securely through the mail.

For more information on the efficient use of resources in the office, check the business waste reduction publications available through the California Integrated Waste Management Board. Call (916) 341-6481, or e-mail us at bzassist@ciwmb.ca.gov

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Last updated: October 21, 2007

Business Resource Efficiency & Waste Reduction http://www.ciwmb.ca.gov/BizWaste/
Business Assistance: bzassist@ciwmb.ca.gov (916) 341-6363