EP21H

Two component epoxy compound for high performance applications
Key Features
  • High temperature resistant
  • Lower viscosity
  • Robust chemical resistance
  • Very long open time
  • Superior physical strength properties
  • Meets NASA low outgassing
Typical Properties
Viscosity
3,000-6,000 cps
Cure Schedule
12-24 hours at 75°F, plus 3-4 hours at 150°F
Hardness
>75 Shore D
Service Temperature Range
-60°F to +250°F
Refractive Index
1.54
Volume Resistivity
>10¹⁴ ohm-cm
Image
EP21H Two Component, Optically Clear Epoxy
Certifications

ASTM E595 Compliant

Meets EU Directive 2015/863

Product Description

Master Bond EP21H is a two component epoxy system with exceptionally good clarity and a unique optical transmission profile for an epoxy. Nearly all epoxies display minimal light transmission below 330 nm. EP21H has a special crosslinking profile that allows for exceptional light transmission in the 250-365 nm spectra. The light transmission in sections of 0.005 inch or less exceeds almost 95% from 260-2,000 nm. EP21H is easy to handle having a long open time. EP21H will cure at room temperature and it can be accelerated by adding heat. It bonds well to a wide variety of substrates including glass, many plastics, metals and composites. It resists many chemicals including water, oils and cleaning agents. Additionally, EP21H has low shrinkage upon curing, sound electrical insulation properties and a reliable array of physical strength attributes. The color of Part A is clear and Part B is light amber clear. The service temperature range is -60°F to +250°F. EP21H is primarily used in optical, fiber-optic, electro-optic and related applications where this very uncommon light transmission pattern for an epoxy type material is required.

Product Advantages

  • Relatively easy to manage 100:50 mix ratio by weight
  • Exceedingly long working life
  • Low viscosity; readily applicable for bonding, sealing, coating and encapsulating
  • Very good physical strength properties
  • Splendid electrical insulation properties
  • Very special optical transmission properties
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How to order

Verify Your Product Selection

With thousands of custom formulations available, our expert engineers provide personalized consultation to ensure you select the ideal adhesive. We will follow up with a product and packaging recommendation for your specific application.

Get a Quote

Our customer service team will follow up with a detailed quote with packaging and shipping options.

Place Your Order

We'll work with your company to process the order efficiently.

Receive Your Material

Your adhesive will be made to order and shipped to you. Typical lead times are 10-14 business days, with rush options available for urgent orders.