# Pigment and Filler Compounding for Liquid Latex Human page: https://retifist.com/literature-reviews/liquid-pigment-filler-decks > **Safety.** Pigments and fillers change skin-contact extractables and aging chemistry. Food-contact colorant lists are not wear certificates. Copper and manganese consume antioxidant. Compounding literacy, not a home recipe card. ## Executive summary Color and opacity in cast or dipped NR enter as compounding: dyes and pigments are optional Class 3 elastomer-phase modifiers alongside sulfur, zinc oxide, accelerators, clays, and antidegradants.[^1] A film from raw latex is not a saleable article until compounded.[^2] Insoluble solids and immiscible liquids must be dispersed or emulsified before latex addition or the colloid is upset.[^2][^3] Fillers raise modulus and can cut stretch; polymeric fillers can raise tear and set. Metals in pigments accelerate aging. Use when tinting a batch, chasing opacity, or evaluating dry powder dumped into latex. Surface paint is a different class: [Painting vs Compounding Pigment](/literature-reviews/liquid-painting-vs-compounding-pigment). Fit stiffness: [Gauge, Modulus, and Reduction](/literature-reviews/liquid-gauge-modulus-reduction). --- ## Compound before film formation Color is part of the compound package. Industrial aqueous pigment dispersions whose TDS lists rubber latex are the documented tint path.[^6] --- ## Identity buckets | Bucket | Prep | Failure if skipped | | --- | --- | --- | | Aqueous pigment dispersion | Add when compound stable | TDS may list rubber latex[^6] | | Dry pigment powder | Dispersion **<5 µm** before latex[^3] | Undispersed powder shocks colloid | | Oil-phase colorant | Oil-in-water emulsion first[^4] | Oil spots on film | | Mineral filler | Slurry in water + dispersant before latex[^5] | Modulus up; keep load low for soft film | | Polymeric filler (high-styrene SBR latex) | Add as latex[^7] | Tear up; modulus and set up | Dispersion target **<5 µm** (many industrial dispersions 90% ≤2 µm); Hegman QC; remix before weigh-up.[^3] Emulsions: drop test; homogenize ≤38°C; casein swell window about 54–71°C.[^4] --- ## Loading trade-offs **Mineral clay.** DIXIE clay 0 → 50 phr (CR example) tensile **3100 → 1500 psi**; stress at 500% **500 → 1100 psi**.[^8] **High-styrene SBR.** At 20 phr in NR film: crescent tear **1769 N/cm**, 300% modulus **2.76 MPa**, permanent set **30%**; handbook flags modulus rise as a disadvantage for some applications.[^7] **Adhesive-filler analogy.** Mineral fillers in latex adhesives typically **0–30 pphp**; higher load cuts tack and raises stiffness.[^9] Same stiffness-versus-extensibility tension; not a garment recipe. --- ## Metal impurities Copper protection, when needed: **2 phr total** antioxidant; coarse or settled dispersions give uneven protection.[^10] ISO 2004 concentrate limit Cu/Mn **8 mg/kg** solids.[^11] Pigments, dyes, and fillers can re-introduce metal catalysis.[^10][^11] Related: [Antidegradants in DIY Compounds](/literature-reviews/liquid-antidegradants-diy-compounds); [Aging, Storage, and Care](/literature-reviews/liquid-aging-storage-and-care). --- ## Decision cues - Tint in the compound for batch color, opacity, or polymeric-filler tear tuning when dispersion or emulsion prep is executable. - Prefer aqueous dispersions whose TDS lists rubber latex; add after the cure package is stable. - Oil spots, grit, or a shocked (suddenly thick) compound are colloid failures: remake the prep. --- ## Endnotes [^1]: Vanderbilt Latex Handbook — Introduction; Class 3 modifiers include dyes and pigments. [^2]: Vanderbilt Latex Handbook — latex definition; raw film needs compounding; insoluble solids / immiscible liquids must be prepared first. [^3]: Vanderbilt Latex Handbook — Dispersions chapter; <5 µm target; Hegman QC; remix before weigh-up. [^4]: Vanderbilt Latex Handbook — Emulsions chapter; oil-spot failure; drop test; homogenize ≤38°C. [^5]: Vanderbilt Latex Handbook — Slurries chapter; mineral fillers slurry-prepared before latex. [^6]: Aqueous pigment dispersion TDS class listing rubber latex (example in corpus: BASF Aurasperse applications include Rubber Latex). [^7]: Polymer Latices Vol 3 — Application of Latices — §16.6.2; high-styrene SBR polymeric filler (handbook Table 16.12 series). [^8]: Vanderbilt Latex Handbook — DIXIE clay filler series. [^9]: Polymer Latices Vol 3 — Application of Latices — §22.2.5 adhesive fillers; typical 0–30 pphp. [^10]: Vanderbilt Latex Handbook — antidegradant chapter; copper protection 2 phr total. [^11]: ISO 2004 — NR latex concentrate; Cu/Mn max 8 mg/kg total solids.
Deep dive: High-styrene SBR polymeric filler NR base (100 dry), KOH 0.5, sulfur 1, activated dithiocarbamate 3, ZnO 5, octylated diphenylamines 1; high-styrene SBR latex 0 / 10 / 15 / 20 phr; vulcanize 15 min at 93°C.[^7] Plant example, not a home mixing card. | 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 |
Deep dive: Dispersion and emulsion prep Dispersions: anionic/nonionic DARVAN-class aids; pebble mill ~50% media charge; <5 µm; Hegman at ~30% TS; remix; overgrind can agglomerate.[^3] Emulsions: in-situ soaps or DARVAN ME/WAQ; 2–10% oil in oil phase often helps; 65% antioxidant emulsion example uses phase inversion then homogenize ≤38°C; drop test.[^4]
Deep dive: Mineral clay direction CR 750 + DIXIE clay 0 / 25 / 50 phr (60 min at 127°C): tensile **3100 / 1800 / 1500 psi**; stress at 500% **500 / 600 / 1100 psi**.[^8]