Hi Jewels,
The law tag lists contents by weight not by thickness so it doesn’t tell you how thick the layers are. Materials that are denser and weigh more will show up as a higher percentage compared to their relative thickness in the mattress and lower density materials will show up as having a lower percentage compared to their relative thickness.
If a law tag mentions 25% cotton and it doesn’t show up in the layering details then I would ask them about it.
Cotton is a good quality and durable material especially if it’s tufted to prevent any shifting and to precompress it. Densely packed cotton batts tend to be firmer than soft foam layers so they are often used in deeper layers under softer materials. There is a little more about cotton in mattresses in post #2 here. It’s not used as often in mattresses any more because it’s more costly than polyfoam but unlike foam materials which become softer over time … natural cotton (and other natural fibers) will pack down somewhat over time and become firmer so there is less risk to alignment due to materials that soften and they can help offset any softening in other materials. Thicker layers of cotton can develop impressions as they pack down if they aren’t well tufted or evened out by sleeping in different areas of the mattress or in a two sided mattress by flipping the mattress) but the impressions in natural fibers are firmer rather than softer so they are less risky for alignment.
Phoenix