Antidegradants in DIY Compounds
Not a recipe. The phr numbers below are handbook ranges. More antioxidant is not always better. Stain, bloom, and cost are real trade-offs.
Executive summary
Latex articles cannot be stopped from degrading. Heat, humidity, UV, ozone, oxygen, oils, metals, and stress only change the speed. If you mix a liquid-latex compound for a film that should last past one event, plan an antioxidant. Thin goods typically sit at 0.5–2 phr; Vanderbilt’s antidegradant chapter often lands at 1–2 phr total. Amines protect more and discolor. Phenolics stain less and protect less.
Use this when you are compounding a film you want to keep. Storage and wear environment sit in Aging, Storage, and Care. Pigments that bring copper sit in Pigment and Filler Compounding.
What “retard” means
Three oxidative modes run at once:
- Chain scission: the film goes soft and tacky
- Crosslinking: the film hardens and loses stretch
- Chemical alteration: color and surface chemistry drift
Crack pattern helps you name the driver:
| Pattern | Looks like |
|---|---|
| Ozone | Oriented cracks, widespread across the exposed face |
| Flex | Oriented cracks, local to the crease or joint |
| UV | Non-oriented cracks over the area that saw light |
Map the cracks before you blame “old glue.”
What is an antidegradant?
An antidegradant is a chemical mixed into the latex to slow aging. The umbrella covers antioxidants (oxygen and heat), antiozonants (ozone, including PPD types), and waxes that bloom into a physical ozone skin. None of them make the article immortal.
What does phr mean?
phr is parts per hundred rubber. 1 phr antioxidant is 1 part per 100 parts dry rubber.
Budget in the compound
Add an efficient antioxidant to most latex compounds. Blackley puts typical use at 0.5–2 phr, especially in thin-walled goods. Vanderbilt’s chapter says most latex products use 1–2 phr total. Those ranges overlap; they are not a single recipe.
Amine antioxidants work harder and discolor the film. Phenolic antioxidants stain less and protect less. A light pastel costume film and a black glove film will not want the same choice.
Match the package to storage and wear: ozone from motors, UV in a window, copper in hardware or a dirty pigment. Do not copy a glove-factory phr onto a thin cast panel just because the number is printed in a table.
When copper protection is the point, Vanderbilt budgets 2 phr total antioxidant. Coarse dispersions leave gaps. See Pigment and Filler Compounding.
Ozone: wax vs PPD
Microcrystalline wax at 0.5–1.0 phr builds a static ozone barrier after it blooms to the surface as a continuous skin. Stretch or flex cracks that skin. Then ozone gets in. Time-to-fail after a stretch is a handbook topic; the practical point is that wax helps a piece that sits still.
PPD-type antiozonants (ANTOZITE-class in Vanderbilt) at at least 2 phr, often 3 phr, are the dynamic-ozone tools. They stain dark. A flexing cuff or a piece that lives near a motor wants this thinking, not more wax.
A UV-absorber packaging film can be cheaper than loading UV absorbers into the article itself.
Heat stacks the clock
Oxidation rate doubles about every 8.3°C. A handbook warehouse example: floor-to-ceiling temperatures around 35–60°C in warm months, so ceiling stock can age about eight times faster than floor stock. Avoid sharp folds. Faces left in clear plastic in the sun discolor.
A mixed compound on a top garage shelf in August is living that example. Antioxidant in the recipe does not cancel hot storage.
Decision cues
Budget 0.5–2 phr antioxidant (expect 1–2 phr on many industrial cards) when the film should outlast a single wear.
Pick phenolic when stain matters more than maximum protection. Pick amine when protection matters more than color hold.
Wax for a piece that will sit still in storage. PPD-class when the piece will flex in ozone. Both stain and bloom; neither is “more is better.”
Deep dives (optional)
Deep dive: Wax bloom vs PPD
Microcrystalline wax 0.5–1.0 phr: static ozone skin after a continuous bloom. Flex or stretch breaks the bloom; the film can then fail in hours in a strong ozone atmosphere (handbook aging series). PPD antiozonants ≥2 phr, often 3 phr, for dynamic ozone; they stain dark.
Deep dive: Warehouse heat
Handbook warehouse: about 35–60°C floor to ceiling in warm months. Rate doubles per 8.3°C, so the top pallet ages about 8× the floor pallet. Packaging: no sharp folds; UV through plastic or cellophane discolor the exposed face. A hot garage top shelf is the same physics at hobby scale.