ASTM D2851-15(2023) PDF

Overview

ASTM D2851-15(2023) is a globally recognized standard specification developed by ASTM International for liquid optical adhesives. This standard outlines the essential properties and testing requirements of liquid adhesives used for bonding glass to glass or other transparent materials. It aims to ensure that liquid optical adhesives are of high quality, providing strong, clear, and stable bonds, critical for optical and photonic applications. The specification prescribes strict criteria for physical properties, cleanliness, transparency, and performance, supporting industries that demand exceptional adhesion and optical clarity.

Key Topics

• Adhesive Formulation and Application

  • Adhesives must be liquid and free of solvents to prevent bubble formation.
  • Each component must be fully reactive with no residual volatile products.
  • Adhesives may be cured by heat, catalyst, or radiation.

• Performance Criteria

  • Volatility: Volatile content must be minimal to maintain adhesive integrity.
  • Viscosity: Defined viscosity ranges ensure consistent application.
  • Color: Low color index maintains optical clarity.
  • Cleanliness: Strict limits on foreign particle content prevent defects.
  • Refractive Index: Adhesive must match the refractive index of bonded materials as agreed upon by manufacturer and user.
  • Stability: Adhesive should not undergo significant changes in viscosity or solidify under specified conditions.

• Optical Properties

  • Light Transmission: Adhesive layer must provide at least 98.5% of the light transmission compared to a single glass disk and retain this after environmental testing.

• Environmental Resistance

  • Environmental Testing: Adhesive bonds must maintain integrity after exposure to humidity, temperature extremes, and accelerated weathering.
  • Bond Strength: Adhesive must exhibit specified minimum tensile strength after environmental exposure.

• Safety and Compliance

  • Users must establish suitable safety, health, and environmental practices when using and testing adhesives.

Applications

ASTM D2851-15(2023) is widely applied in industries where optical clarity and robust bonding are paramount. Examples include:

• Precision Optics Manufacturing: Bonding of glass components in lenses, prisms, and optical assemblies.
• Photonic Devices: Assembly of light-transmitting components, sensors, and detectors.
• Display Technology: Securing glass substrates and transparent panels in LCDs, OLEDs, and touchscreens.
• Scientific Instrumentation: Creating airtight, optical-quality seals in microscopes, spectrometers, and laboratory glassware.
• Architectural Glazing: Specialized transparent bonding in architectural or decorative glass installations.

Adherence to ASTM D2851 ensures the highest levels of transparency, reliability, and environmental resistance, supporting the demanding requirements of optical and photonic devices.

Related Standards

ASTM D2851-15(2023) references and aligns with several related standards to comprehensively address optical adhesive quality:

• ASTM D542: Test Method for Index of Refraction of Transparent Organic Plastics
• ASTM D897: Test Method for Tensile Properties of Adhesive Bonds
• ASTM D904: Practice for Exposure of Adhesive Specimens to Artificial Light
• ASTM D907: Terminology of Adhesives
• ASTM D1084: Test Methods for Viscosity of Adhesives
• ASTM E308: Practice for Computing the Colors of Objects by Using the CIE System
• ASTM E1953: Practice for Description of Thermal Analysis and Rheology Apparatus

Organizations and manufacturers working in optical adhesive applications are encouraged to review and apply these referenced standards to ensure comprehensive compliance and optimal product performance.

Keywords: ASTM D2851, liquid optical adhesive, glass bonding, optical clarity, adhesive standards, transparency, environmental resistance, tensile strength, international specification, adhesives for optics.