Nylon | Polypropylene | Polyester | Wool | |
Market | 60% | 30% | 8% | 2% |
“Hand” | Good | Poor | Very Good | Excellent |
I.D. Method | Dissolves in formic acid. Burns to a hard black bead; puffs white smoke;extinguishes | Floats in water. Burns to a round hard tan bead. | Dissolves in hot meta-cresol. Burns rapidly to a round hard bead and gives off a pungent odor. | Dissolves in chlorine bleach. Burns with a burned-hair odor to a black crumbly residue. |
Moisture Absorption | 4.2-4.5% | 0.01% | 0.04-0.08% | Up to 30% |
Specific Gravity | 1.14 | 0.90 | 1.23 | 1.32 |
Resilience | Excellent | None | Fair | Good |
Abrasion Resistance | Excellent | Very Good | Good | Good |
Effects of Acids, Alkalis, and Solvents | Resistant to weak acids, but decomposes in strong mineral acids | Chemically inert | Resistant to most acids and solvents | Sensitive to acids and alkalis |
Dye Methods | Acid; some solution dyed | Solution dyed | Dispersed Dyes | Various |
Resistance to Mildew, Aging, Sunlight | Excellent resistance to mildew and aging. Prolonged sunlight can cause degradation. | Good resistance to all three | Excellent resistance to mildew and aging. Prolonged sunlight can cause degradation | Damaged by sunlight, mildew, moths, beetles. Sunlight can cause yellowing. |
Color Retention | Very good | Excellent | Good | Good |
Stain Resistance | Poor (5th generation very good) | Excellent | Excellent | Very Poor |
Stains/Soils Attracted to Fiber | Acid dyes, except for 5th generation | Oil based | Oil based | Protein, urine, blood, meat juices |
Melt Point °F | Type6-435º F; Type6,6-490º | 320º F | 509º F | None (ignites) |
Cigarette Burn Resistance | None | None | None | Very good |