table of contents

1. overview

2. carbon black ink

 2.1 Composition and Properties

 2.2 Dispersion Process

 2.3 Stability Testing

3. fiber tip design

4. performance characteristics

 4.1 Optical Properties

 4.2 Abrasion and Chemical Resistance

 4.3 Performance on Moist or Wet Surfaces

 4.4 Bleed-Through Prevention

 4.5 Mixing Ball

 4.6 Feathering and Static Charge

5. dry-out prevention

6. adhesion properties

 6.1 Hard, Non-Porous Surfaces

 6.2 Porous Surfaces

7. maintenance

8. conclusion

1. over view

Magic Tag Engineering’s Perma Black marker is a fine porous-tip marker designed for durable, high-contrast labeling in demanding technical environments, including laboratories, industrial facilities, and specialized applications. The marker features a 1 mm porous polymer nanostructured nib housed inside a stainless-steel tip, bakelite polymer components, and an aluminum barrel that houses a mixing ball and 5 ml of ink. The ink is oil-based ink, formulated with carbon black, plant oils, and alcohol-based solvents at pH 6.5–7. The ink is designed to maintain performance across extreme conditions, with resistance to ethanol, isopropanol, acids, alkalis, bleach, peroxide, UV light, heat (up to 800 °C), and cold (down to –200°C).

The porous nib meters ink by capillarity, producing a solid, uniform stroke characterized by edge feathering, blunt initial and terminal strokes, and heavier deposits under pressure. The stainless-steel mixing ball in the barrel mixes the ink after periods of non-use, re-equilibrates the dispersion network, and restores smooth capillary function.

The marker’s performance is enabled by:

• Nanostructured carbon black with tailored surface chemistry for enhanced wettability and stability.
• Multi-week high-energy dispersion achieving sub-200 nm particle distributions with narrow tails.
• Surfactant, dispersant, and coalescent formulations optimizing wetting, colloidal stability, and film formation.
• A sealed cap and nib system maintaining a humid micro-environment to prevent dry-out.

This white paper details the ink formulation, fiber tip design, performance characteristics, adhesion properties, dry-out prevention, and maintenance requirements that together ensure decades-long reliability for precision labeling.

2. carbon black ink

2.1 Composition and Properties

The ink is formulated with carbon black (C.I. Pigment Black 7), a nanostructured carbon produced via partial combustion or thermal decomposition of hydrocarbons (furnace/gas black process). Unlike dye-based inks, carbon black provides exceptional coverage, color stability, and resistance to solvents (e.g., 70% ethanol, isopropanol), acids (pH 2), alkalis (pH 12), bleach (5% NaOCl), peroxide (3% H₂O₂), oxidation, reduction, UV light, and thermal extremes (–200 °C to 300 °C). The labeling marker’s performance stems from:

• Particle Characteristics: Primary particles (10–100 nm, typically 15–30 nm for high jetness) fuse into aciniform aggregates (85–500 nm). Particle size, aggregate morphology, and surface chemistry govern jetness (optical density, OD > 1.5), dispersion quality, and interfacial behavior within the oil-based vehicle.
• Surface Chemistry: Oxidized carbon blacks enhance wettability, reducing viscosity (5–8 cP) and improving dispersion stability. Surface oxygen groups (e.g., functional groups containing carbon and oxygen that attach to the surface of carbon black particles) increase affinity for the liquid phase, minimizing agglomeration.

2.2 Dispersion Process

To ensure smooth flow through the nib’s porous structure and long-term colloidal stability, the carbon black is dispersed to achieve mean particle sizes of 10–100 nm, with the upper tail constrained below ~200 nm. Multi-day to multi-week high-energy bead or ball milling (energy input 100–500 kWh/kg) separates agglomerates, exposes fresh surface area, and ensures complete wetting. The resulting particle size distribution is tuned so that 50% of particles and aggregates are 70–120 nm, with 95% below 190–200 nm, preventing clogging in nib pore throats (0.5–2 µm, see Section 3 Fiber Tip Design) and sedimentation per Stokes’ law (settling velocity ∝ radius²).

The ink is engineered as a true dispersion, not a thickened suspension, using:

• Surface-Treated Carbon Blacks: Oxidized grades enhance wettability, reducing dispersion energy requirements.
• Dispersants and Surfactants: Polymeric (e.g., polyacrylate) or ionic (e.g., sulfonate) dispersants create steric and electrostatic barriers to suppress flocculation. Silicone surfactants (0.5–2% w/w) reduce surface tension to 18–34 dyn/cm, aiding wetting on diverse substrates.
• pH and Ionic Strength Control: A pH of 6.5–7 and low ionic strength (<0.01 M) minimize particle aggregation, ensuring stability for decades without caking.

The oil-based vehicle, comprising plant oil (e.g., linseed or soybean oil) and alcohol-based solvents, balances viscosity (5–10 cP) and evaporation (vapor pressure <10 mmHg at 25 °C), supporting consistent flow and film formation.

2.3 Stability Testing

The ink’s stability is validated through accelerated aging tests (e.g., 85 °C, 85% RH, 1000 hours), showing no sedimentation or viscosity increase (<5% change). Particle size distribution remains consistent post-storage, with 95% of particles below 200 nm after 5 years at 25 °C, ensuring long-term performance.

3. fiber tip design

The marker’s 1 mm nib is a porous polymer matrix constructed from acrylic- or melamine-bound fibers, with a porosity of 0.63–0.70 (63–70% void space) and fiber denier of 5–7 (grams per 9,000 meters). Porosity and denier control:

• Ink Flow Rate: Capillary metering delivers 0.01–0.02 ml/cm² under standard writing conditions (0.1 N load).
• Tip Stiffness: Fibers ensure structural integrity, resisting deformation under 0.5 N pressure.
• Edge Integrity: Minimal edge feathering (0.1–0.2 mm on 80 gsm paper) supports precision labeling.

The nanostructured design produces uniform strokes with pressure-dependent deposition (e.g., 10–20% stroke width increase at 0.5 N), ideal for technical applications like labeling test tubes or circuit boards.

4. performance characteristics

4.1 Optical Properties

High jetness (OD > 1.5) is achieved with clean dispersions, minimizing agglomerates (> 99% below 500 nm). Surface oxidation enhances UV and weather resistance, with no fading (ΔE  < 1.0) after 1000 hours of QUV exposure (ASTM G154). The ink maintains consistent mass tone across substrates.

4.2 Abrasion and Chemical Resistance

The ink forms a durable acrylic/polymer film (2–5 µm thick) on hard surfaces, withstanding 500–1000 cycles in ASTM D4060 abrasion tests and 100 wipes with 70% ethanol. Carbon black’s insolubility ensures resistance to acids (pH 2), alkalis (pH 12), bleach (5% NaOCl), and peroxide (3% H₂O₂), with no degradation after 1000 hours at 85% RH, 40 °C.

4.3 Performance on Moist or Wet Surfaces

Low surface tension (18–34 dyn/cm), achieved via silicone surfactants, enables wetting on moist substrates (e.g., autoclaved vials, wet metal). The ink forms stable films over thin water layers, maintaining adhesion under 100% RH conditions.

4.4 Bleed-Through Prevention

On porous substrates, controlled surfactants and humectants limit penetration (<0.1 mm on 80 gsm paper), minimizing bleed-through. The oil-based vehicle balances capillarity and surface tension, unlike alcohol-only markers with rapid wicking.

4.5 Mixing Ball

A stainless-steel mixing ball (3–5 mm diameter) resuspends carbon black, re-equilibrates the micro-rheology network, purges micro-bubbles, and primes the nib, ensuring consistent flow and optical density after storage (e.g., 6 months at 25 °C).

4.6 Feathering and Static Charge

The ink carries a charge, increasing feathering on statically charged plastics (0.2–0.3 mm edge spread). Using an ionizer reduces feathering to <0.1 mm, restoring edge definition for precision labeling.

5. dry-out prevention

Dry-out refers to the gradual loss of ink functionality when the solvent at the exposed tip of a fiber- or felt-tip marker evaporates, causing pigments and resins to concentrate and form a crust that blocks ink flow. This can result in thin, unclear, or impossible writing strokes, potentially obstructing capillary channels and damaging performance. Dry-out is mitigated through:

• Ink Formulation: The plant oil-based vehicle, supplemented with alcohol-based solvents, reduces evaporation (vapor pressure <10 mmHg at 25 °C) compared to low molecular weight alcohol-only systems (30–50 mmHg). Viscosity is optimized at 5–10 cP for flow and stability.
• Sealed Cap System: Sacrificial-solvent or elastomeric shutter caps create a saturated vapor micro-environment, extending cap-off times to 24–48 hours (vs. 1–2 hours for alcohol-based markers). This prevents pigment/resin crusting, ensuring clear strokes.

6. adhesion properties

6.1 Hard, Non-Porous Surfaces

On glass, metal, and plastics, low surface tension enables wetting, forming a thin acrylic/polymer film (2–5 µm) post-evaporation. The film anchors carbon black, resisting abrasion (500–1000 cycles, ASTM D4060), solvents (100 ethanol wipes), and environmental stress (1000 hours, 85% RH, 40 °C).

6.2 Porous Surfaces

On paper, cardboard, or wood, capillarity deposits carbon black and binder within surface pores, forming a mechanical interlock. This ensures rub resistance with minimal bleed-through (<0.1 mm penetration), aligning with standards for technical labeling.

7.  maintenance

Periodic cleaning of the cap and barrel opening with a dry or slightly damp cloth removes dried ink residues, preventing friction during cap removal/replacement. This preserves the seal’s integrity and ensures long-term performance without damaging the aluminum barrel or polymer components. Cleaning is recommended after 100–200 uses or monthly during regular use.

8. conclusion

MagicTag Engineering Marker, Perma Black, integrates advanced carbon black dispersion, precision fiber tip engineering, and a sealed cap system to deliver durable, high-contrast labeling across diverse substrates, including moist and wet surfaces. Its robust ink formulation, optimized for stability, chemical resistance, and performance, ensures decades-long reliability, making it an essential tool for high-precision technical applications in laboratories, industrial settings, and beyond. Unlike conventional dye- or alcohol-only markers, the Perma Black system maintains stability, optical density, and adhesion across decades of use and under extreme environmental conditions.