LOCTITE 5181H Black Cyanoacrylate Adhesive is a one-component, high-viscosity instant adhesive developed for bonding rubber, paper, leather, and other porous materials. Its black ethyl-cyanoacrylate formulation cures through surface moisture and provides a controlled, slower curing profile than many standard instant adhesives. This additional positioning time supports part adjustment and visual inspection before the assembly develops handling strength, making the product useful for industrial bonding operations that require accuracy, clean application, and dependable adhesion.

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LOCTITE 5181H Black Cyanoacrylate Adhesive for Porous Materials

LOCTITE 5181H Black Cyanoacrylate Adhesive is supplied ready to use and requires no resin-to-hardener mixing. The single-component format helps simplify manual assembly, dispensing, repair, and production processes while reducing the risk of inaccurate mixing ratios or inconsistent preparation.

The uncured product is a black liquid with a typical viscosity range of 1,600 to 2,750 mPa·s at 22°C. Its high-viscosity consistency offers better placement control than low-viscosity instant adhesives, helping limit unwanted running on absorbent, irregular, vertical, or small bonding areas. The dark color can also make applied adhesive easier to identify during assembly inspection.

Key Benefits of LOCTITE 5181H Black Cyanoacrylate Adhesive

LOCTITE 5181H Black Cyanoacrylate Adhesive combines fast moisture-activated bonding technology with a deliberately slower curing response that allows limited repositioning. This balance is valuable for parts that must be aligned carefully before the bond reaches fixture strength.

One-component adhesive with no mixing required
High viscosity for controlled and accurate dispensing
Black color for visible application and inspection
Designed for rubber, paper, leather, and porous substrates
Suitable for materials with different thermal expansion rates
Slower curing profile allows limited part repositioning
Develops strong adhesion after complete curing

Under the manufacturer’s stated test conditions, fixture time on EPDM rubber is up to approximately 75 seconds. Full functional strength develops relatively quickly, but curing continues for at least 24 hours before full chemical and solvent resistance is achieved. Actual fixture and cure times depend on substrate type, moisture level, bond gap, temperature, and adhesive quantity.

Applications of LOCTITE 5181H Black Cyanoacrylate Adhesive

LOCTITE 5181H Black Cyanoacrylate Adhesive is recommended for bonding rubber components, paper products, leather parts, absorbent materials, and compatible porous substrates. Typical uses may include rubber seals, gaskets, leather accessories, paper-based assemblies, industrial trim, protective pads, flexible components, and mixed-material parts.

The adhesive is also suitable for joining materials with different coefficients of thermal expansion. This makes it useful for selected assemblies where bonded substrates respond differently to temperature changes. Application testing is essential because surface treatments, plasticizers, coatings, moisture content, and material additives can influence bonding performance.

After 24 hours of curing at 22°C, the manufacturer reports a typical aluminum-to-aluminum tensile strength of approximately 17 N/mm². The cured material also provides a typical softening point of 165°C and dielectric breakdown strength of 11.6 kV/mm, supporting selected bonding applications that require mechanical strength and electrical insulation.

How to Apply LOCTITE 5181H Black Cyanoacrylate Adhesive

Clean the bonding surfaces and remove dust, oil, grease, moisture, oxidation, release agents, and loose particles. Apply a small, controlled quantity to one surface. Excessive adhesive may slow fixture development and reduce joint consistency, so the bond line should remain thin and uniform.

Assemble and align the parts promptly. Use the product’s slower fixture profile to make minor positioning corrections before handling strength develops. Maintain contact until the components remain securely fixed, then allow the assembly to cure fully before chemical exposure, heavy loading, or performance testing.

Storage of LOCTITE 5181H Black Cyanoacrylate Adhesive

Store the unopened container in a dry location between 2°C and 8°C. Prevent contamination and never return dispensed material to the original package. Review the latest technical data sheet and safety data sheet before industrial use.

LOCTITE 5181H Black Cyanoacrylate Adhesive is a practical choice for manufacturers seeking high-viscosity dispensing, visible application, controlled fixture time, and reliable bonding of rubber, leather, paper, porous substrates, and compatible mixed-material assemblies.

Explore our industrial cyanoacrylate adhesives for additional high-speed and specialty bonding solutions.

View the official LOCTITE 5181H Technical Data Sheet from Henkel for current product specifications.

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