Both OIT (octylisothiazolinone) and DCOIT (dichloro-octylisothiazolinone) are broad-spectrum isothiazolinone biocides widely used in industry. 

Their principal applications are summarized below.

OIT (Octylisothiazolinone)

Paints & Coatings

  Dry-film fungicide and preservative for both latex and solvent-based systems; does not affect film stability or cause discoloration, chalking, or cracking.

Inks & Lubricants

  Preservative for oil-based formulations, extending product shelf life.

Leather & Wood  

  Protects leather chemicals, wooden articles, and cultural-heritage objects against mold and yeast.

Plastics

  Incorporated into polyethylene, polyurethane, and other polymers to suppress fungal growth.

DCOIT (Dichloro-octylisothiazolinone)

Marine Protection

  Environmentally friendly antifouling agent replacing organotin compounds. Used in ship-bottom paints, marine coatings, fishing nets, etc., 

for long-term protection against algae and barnacles.

Coatings & Plastics

  Broadly employed in paints, coatings, polyethylene, polyurethane, and other plastics to prevent mold, bacteria, and algae.

Water Treatment & Papermaking  

  Controls microbial contamination in industrial recirculating water, paper mills, and wastewater treatment.

Other Fields  

  Also used as a mildew-proof and preservative additive in leather, wood, adhesives, inks, etc.

Summary Comparison

| Feature / Application | OIT | DCOIT |

| Primary Function** | Anti-mold, preservative | Anti-mold, anti-algae, preservative 

| Thermal Stability** | Up to ~180 °C | >250 °C |

| Weather Resistance** | Relatively water-soluble; not recommended for prolonged outdoor use | UV-, heat-, and rain-resistant; suitable for outdoor exposure |

| Environmental Profile** | Low toxicity; irritant to skin | Heavy-metal-free, readily biodegradable, eco-friendly |

| Industrial Focus** | Interior coatings, inks, leather, wood products | Marine coatings, plastics, exterior paints, water treatment |

Both exhibit broad-spectrum antimicrobial activity. DCOIT excels in outdoor and marine environments, whereas OIT is preferred for indoor applications or 

when higher water solubility is advantageous.