Colored Sheet: Pigment and Filler Effects
Safety. Colorants and fillers change what can extract at the skin and how the sheet ages. A food-contact colorant list is not a wear certificate. Copper and manganese in a pigment consume antioxidant. This page is literacy about sheet you already bought, not a mixing card.
Executive summary
When you buy red, black, or opaque calendered roll goods, the mill already put the color and any fillers in. You inherit opacity, modulus, and the aging package as sold. Mineral fillers make the sheet stiffer and weaker in tension. Some polymeric fillers raise tear but also raise set. Pigments can bring metal impurities that speed aging.
Use this when you are choosing a catalog color, comparing a clear roll to an opaque one, or wondering why one vendor’s “same thickness” feels boardier. For graphics printed on sheet you already have, see Printing and Surface Decoration. Stiffness as a fit lever sits in Gauge, Modulus, and Reduction.
What you bought with the color
Fashion NR sheet often ships in standard colors. The mill compounded the rubber, formed the film, and sold you a finished face.
A catalog black roll already has its opacity. A clear roll from the same shop is a different compound. If the black feels boardy next to the clear, filler load is a common reason.
Repeatability is what this vendor shipped this lot. If you need the recipe, you need a mill TDS, not a swatch.
What does calendered mean?
Calendered sheet is rubber pressed to thickness between heavy heated rollers (calenders). Fashion roll goods are almost always calendered: they arrive ready to cut and glue.
What does phr mean?
phr means parts per hundred rubber. It is how compound tables count ingredients: 10 phr clay means 10 parts clay per 100 parts dry rubber. Retail sheet almost never prints this number on the roll.
Filler effects you will feel
Fillers are particles mixed into the rubber to add opacity, cheapen the compound, raise tear, or change stiffness. They are already in the sheet. You feel the result.
Mineral clay. A handbook clay series in a CR compound (DIXIE clay, 0 → 50 phr) dropped tensile from 3100 → 1500 psi while stress at 500% stretch rose 500 → 1100 psi. Direction for a soft garment sheet: more mineral filler buys opacity and cost at the expense of hand and elongation. Soft fashion sheet usually keeps that load low.
High-styrene SBR as a polymeric filler. In an NR film series, raising this filler to 20 phr took 300% modulus from 0.90 → 2.76 MPa, crescent tear from 1156 → 1769 N/cm, and permanent set from 6 → 30%. The same handbook calls the modulus rise a serious disadvantage for some latex uses. A body-hug panel that must snap back cares about that set number. A reinforced zone that must not tear may tolerate the stiffer hand.
What do modulus and permanent set mean?
Modulus here is how much force the film takes to stretch a given amount (the handbook quotes stress at 300% or 500%). Higher modulus means a boardier, less “givey” sheet at the same thickness. Permanent set is how much stretch stays after you let go. High set means the piece looks baggy after wear.
Those numbers are plant-film examples, not a vendor recipe for the roll on your table. They tell you why two black sheets of the same thickness can cut alike and wear differently.
Metal in the color
Color chemistry is also aging chemistry. Copper and manganese catalyze oxidation. When a compound needs copper protection, the handbook budget is 2 phr total antioxidant; coarse or settled dispersions leave weak spots. Pigments and fillers can put those metals into the film the mill sold you.
A cheap bright pigment is an identity risk (metal soap, mineral impurity), not only a color shift. Store the roll like something that will age: Aging, Storage, and Care.
Decision cues
Buy colored sheet when you need a catalog color now and you accept the mill’s opacity, stiffness, and aging package.
Compare lots by hand, not by color name. Stretch a scrap to 300%, let go, and feel set. If two blacks from two shops disagree, treat them as different compounds.
Ask the vendor for polymer family and any filler or color TDS if the piece must last or sit in sun. No TDS means you are trusting the lot.
Deep dives (optional)
Deep dive: High-styrene SBR filler numbers
NR latex base; high-styrene SBR copolymer added at 0 / 10 / 15 / 20 phr; vulcanize 15 min at 93°C. Plant example.
| phr filler | Modulus 300% (MPa) | Tensile (MPa) | Eb (%) | Tear (N/cm) | Set (%) |
|---|---|---|---|---|---|
| 0 | 0.90 | 28.6 | 880 | 1156 | 6 |
| 10 | 2.07 | 30.0 | 800 | 1489 | 20 |
| 15 | 2.41 | 30.7 | 760 | 1664 | 22 |
| 20 | 2.76 | 26.9 | 730 | 1769 | 30 |
Tear-first zones might tolerate the high load. A panel that must stay low-set should treat 20 phr as a stiffness warning.
Deep dive: Mineral clay direction
CR 750 compound with DIXIE clay at 0 / 25 / 50 phr (industrial cure 60 min at 127°C): tensile 3100 / 1800 / 1500 psi; stress at 500% 500 / 600 / 1100 psi. The teaching point is the direction (stiffer, weaker in tension), not the absolute psi on a hobby-cured fashion sheet.