When a fractional-horsepower motor in a power drill or blower fails before its time, the source of the problem is often traced back to the insulation. 

The choice of insulation paper determines mechanical durability, thermal performance, and dielectric integrity throughout the equipment’s service life. COPACO insulation paper, manufactured by Cottrell Paper Company in Rock City Falls, New York, has been meeting that standard since 1926.

Built From Cotton, Engineered for Electrical Performance

COPACO electrical insulation paper is a high-density presspaper manufactured exclusively from new cotton cuttings. Not recycled fiber, not wood pulp, not synthetic blend. 

The cotton undergoes thorough cleaning and special refining before sheet formation, leaving a material with no sizing, clay, fillers, or chemical additives. That absence of impurities is by design: contaminants accelerate aging, reduce dielectric consistency, and introduce failure points under electrical stress.

The result is a smooth-finished, high-density sheet with measurable mechanical advantages: exceptional tensile strength, strong tear and puncture resistance, high burst strength, and reliable dielectric properties from .003″ to .125″ in thickness. COPACO also punches, folds, forms, and creases cleanly, which matters in high-volume assembly operations.

Cottrell produces two primary grades. Standard COPACO rag paper serves the broadest range of motor and transformer applications. COPACO 125 insulation paper is formulated for more demanding performance thresholds. Both meet MIL-I-695 Type “R” specifications.

Where COPACO Electrical Insulation Paper Gets Specified

Blower motors, fuel pump motors, windshield wiper motors, power tools, drills, saws, shop vacs, and electric razors all fall within the scope. Phase insulation in the same motor categories is another documented use.

On the transformer side, oil filled transformer insulation paper requirements are among the most performance-sensitive in the industry. At tap locations within the coil, COPACO’s blue-gray sheet folds over the taps as a tap pad.

That resistance allows manufacturers to reduce tap pad thickness while meeting or exceeding original design requirements. The result is a more compact coil pack with a reduced air gap, improved thermal conductivity, and less copper, oil, and steel per unit. The cost and weight implications at scale are direct and measurable.

COPACO is also specified for cores, corner shields, gaskets, washers, safety shields on terminal strips, and lead wire insulation for scuff resistance.

Why Electrical Grade Rag Paper Outperforms Wood-Pulp Alternatives

Wood pulp papers, including standard Kraft, contain lignin and other organic compounds that degrade under heat and electrical stress. Cotton cellulose is chemically stable, thermally durable, and free from the ionic contaminants that reduce dielectric performance.

The performance gap shows up directly in puncture resistance. COPACO cotton cellulose paper is four times more puncture-resistant than conventional Kraft pressboard at the same thickness. For tap pad applications in oil-filled distribution transformers, that means using thinner material while still exceeding design specs. Less mass per pad, narrower pad width when folded, and lower insulation cost per unit.

Nearly 100 Years of Production at the Rock City Falls Mill

Cottrell Paper Company operates out of a 100,000-square-foot plant at the foothills of the Adirondack Mountains. The mill has been family-owned and operated since 1926, now in its fourth generation. The same raw material standards, refining processes, and quality controls that defined COPACO in its early decades remain in place today.

Raw material sourcing begins with new cotton cuttings, such as clean, controlled-source fiber, not recovered textile waste. Process water is returned to the stream in a chemically purer state than when drawn in. Fiber waste is composted into a soil enhancer. The facility runs in part on on-site hydroelectric generators, and an investment in a natural gas pipeline and high-efficiency boiler has further reduced the plant’s carbon footprint.

Common Questions About COPACO Insulation Paper

How does COPACO compare to other insulation paper suppliers?

Cottrell Paper Company is an electrical insulation paper manufacturer and specialty electrical paper supplier with nearly 100 years of continuous domestic production. The product line includes made in USA insulation paper for motors, transformers, and specialty electrical equipment, including high dielectric insulation paper grades built for demanding applications.

How do I place an order? 

Cottrell Paper Company is located at 1135 Rock City Road, Rock City Falls, NY 12863. Open Monday through Friday, 8 AM to 4 PM. Call (518) 885-1702 or use the quote builder. 

Not sure where to start? Cottrell’s estimate calculator helps procurement teams work out quantities before requesting a quote.