isocyanate

Thân thiện

A chemist carefully handles a sealed container of isocyanate in the laboratory.

Definition

1. Noun:
   • A salt or ester of isocyanic acid: An isocyanate is a chemical compound containing the functional group -N=C=O. It is a highly reactive compound, primarily used in the industrial production of polyurethane foams, coatings, adhesives, and elastomers.

Usage

• is a technical term used predominantly in chemistry, industrial manufacturing, and occupational safety contexts.
• It is a countable noun (e.g., an isocyanate, various isocyanates).
• Due to its reactivity and potential health hazards (it is a known respiratory sensitizer), the word is often used in discussions about safety, exposure limits, and handling procedures.

Examples

• Noun:
  • The factory produces flexible foam by reacting a polyol with an isocyanate.
  • Toluene diisocyanate (TDI) and methylene diphenyl diisocyanate (MDI) are the most common industrial isocyanates.
  • Proper ventilation is essential when working with isocyanates to prevent inhalation.

Advanced Usage

• "Blocked isocyanate": An whose reactive group has been temporarily deactivated by a blocking agent. It becomes reactive again upon heating, which is useful in coatings and adhesives.
  • The paint formulation uses a blocked isocyanate as a crosslinker that activates during the curing process.
• "Isocyanate exposure": A term used in occupational health referring to contact with compounds, which can cause asthma and other respiratory issues.
  • Workers must wear appropriate respirators to minimize the risk of isocyanate exposure.

Variants and Related Words

• Diisocyanate (n): An containing two -N=C=O functional groups. This is the most common type used in polymer production (e.g., MDI, HDI).
• Polyisocyanate (n): An with more than two -N=C=O groups.
• Isocyanic acid (n): The parent acid (HN=C=O) from which are formally derived.

Synonyms

• There are no direct common-language synonyms for this precise chemical term. In very broad descriptive contexts, one might use reactive chemical intermediate or polyurethane precursor, but these are not synonyms.

Related Phrases

• Isocyanate group / functionality: Refers specifically to the reactive -N=C=O unit within a molecule.
  • The prepolymer's properties depend on its isocyanate group content.
• Isocyanate index: A ratio in polyurethane chemistry expressing the amount of used relative to the theoretical amount needed to react with all active hydrogen groups.
  • An isocyanate index above 100 means an excess of isocyanate was used in the formulation.

Học thuật

Noun

1. a salt or ester of isocyanic acid