Copolymer line

Copolymer is the same monofilament, made from two or more polymers instead of one. The strand stays solid and the way it is drawn is unchanged; what changes is the recipe.

Why mix at all

In pure nylon the properties are tied to each other: making it less stretchy means making it stiffer, making it softer means adding stretch. They do not turn independently.

By blending polymers a maker shifts the trade-off rather than removing it. So a copolymer is properly compared not on «better or worse» but on the question: what exactly has been shifted here, and what was paid for it.

What usually gets shifted

Most often stretch, downwards, towards braid, while keeping enough of monofilament's ability to absorb a lunge. Second most often abrasion resistance, and third stiffness, so that the line remembers the spool less.

On stretch itself, and on why it is work rather than a flaw, see the entry on monofilament line.

What it costs

The price differs each time, and the maker does not name it. Less stretch means less margin on a hard strike. More stiffness means worse behaviour on the fixed spool of a spinning reel.

So a copolymer is not «monofilament with the drawbacks removed» but monofilament with the drawbacks rearranged. Which ones can only be read off the description of that particular line.

It ages just the same

Blending polymers does not change the family: a copolymer behaves as nylon does and ages just the same — from water, heat and ultraviolet, with no fishing involved at all. «Expensive line does not perish» does not hold here.

You test it the way you test monofilament, and store it the same way — line care and storage.

Coated line is a third thing

Alongside copolymer you will find monofilament with a fluorocarbon coating, and that is yet another thing, neither of the two. Its core is nylon and the fluoropolymer sits outside as a thin layer, so it does not give the properties of true fluorocarbon.

How to recognise it

The packet says «copolymer», or simply lists several polymers in the composition. There is no separate marking here of the X8 kind, and by touch a copolymer cannot be told from nylon.

What we do not state here

How many times stronger or less stretchy a copolymer is than nylon. The figures vary from line to line, and we found no verified source for a general comparison. Choosing for the tackle follows the same order as everything else — how to choose line.