How to Select Specialty Adhesives, Sealants and Compounds
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Specialty adhesives, sealants, and compounds are specialized and/or proprietary products with unique chemistries, cure technologies and/or compositions.
Specialty Adhesives Basics
Adhesives are organic or inorganic chemical compounds used to join components. Sealants are liquid compounds that prevent leaks and block the ingress of unwanted materials. There are many different types of specialty adhesives, sealants and compounds. Examples include levelers, fillers, chocking materials, mastics, caulks, grouts, and thread lockers. Common forms include binders, resins, greases, pastes, and pellets. Electrically conductive products provide low resistivity and are used to prevent electrostatic discharge (ESD), electromagnetic interference (EMI), and radio frequency interference (RFI). They are also used for electrical insulation and as dielectric materials.
Specialty adhesives are frequently required for specialty applications. For example, products with very high temperature resistance may be used in the aerospace industry, while adhesives featuring high resistance to acids, bases, and strong solvents are used in extreme environments.
Specifications
Chemical System
Specialty adhesives, sealants, and compounds use many different chemical systems. Some contain acetals, acrylics, elastomers, natural or synthetic rubbers, epoxy resins, water-based resins, wax-based binders, starches and starch pastes, volatile organic compounds (VOCs), silicone compounds, or vinyl systems. Others contain bituminous substances, butyls, ceramic or inorganic cements, cyanoacrylates, ethylene copolymers, styrene copolymers, fluropolymers, glues and gums, phenolics, formaldehyde resins, polyamides, or polyimides. Commonly used chemical systems for specialty adhesives, sealants and compounds include polybutadiene, polyethylene (PE), polyester, polyetherimide, polyolefin, polypropylene (PP), polysulfide, and polyurethane (PUR). Filled or reinforced compounds consist of resins with additional modifiers such as fillers, pigments, or chopped fibers.
Curing
There are several curing technologies for specialty adhesives, sealants and compounds. Examples include air setting, film drying, and anaerobic curing. Many thermoplastics and hot melt adhesives are cured using heat or heat and pressure. Vulcanization, a thermosetting reaction, uses heat and/or pressure in conjunction with a vulcanizing agent to produce materials with greatly increased strength, stability, and elasticity. Some materials cure or vulcanize at room temperature. Others cure with radiation, electron beam irradiation, visible light, or ultraviolet (UV) light. Single component curing systems consist of a resin that hardens through the application of heat or a reaction with surface moisture. Two-component and multi-component curing systems consist of two or more resins and a hardener, crosslinker, activator or catalyst. Pressure sensitive adhesives (PSA) and non-corrosive curing systems for specialty adhesives, sealants and compounds are also available.
Applications
Specialty adhesives, sealants and compounds are used in many industries and applications. Some products are used in aerospace, automotive, marine, military, photonics, optical, or tooling applications. Others are designed for use with electrical power products, high voltage applications, semiconductors, or integrated circuit (IC) packaging. Specialty adhesives, sealants, and compounds that are suitable for medical, pharmaceutical and food processing applications meet requirements established by the Food and Drug Administration (FDA) and the U.S. Department of Agriculture (USDA). Original equipment manufacturers (OEMs) and repair, maintenance and overhaul (MRO) organizations also use specialty adhesives, sealants and compounds.
Related Products & Services
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Anaerobic Adhesives and Anaerobic Sealants
Anaerobic adhesives and anaerobic sealants cure in the absence of air or oxygen.
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Electrical and Electronic Resins
Electrical and electronic resins includes adhesives, greases, pads, stock shapes, tapes, encapsulants, potting compounds, thermal interface materials, and electrically conductive substances used in electrical, electronics, and semiconductor applications.
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Hot Melt Adhesives
Hot melt adhesives are solvent-free chemical compounds that are used to join materials. They can be repeatedly softened by heat and hardened or set by cooling, allowing parts to be removed or repositioned during assembly.
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Plastic and Rubber Balls
Plastic and rubber balls are rolling, spherical elements that have low friction values and require little or no lubrication. They are lighter than metal balls and resistant corrosion and abrasion. Some plastic balls resist high temperatures, but others do not. Rubber balls are characterized by a high degree of flexibility and elasticity.
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Polymers and Plastic Materials
Polymers and plastic materials are organic, synthetic or processed polymers that are supplied as raw materials. They typically consist of thermoplastic or thermosetting resins in the form of pellets, powders or liquid resins. These materials can then be molded into a variety of shapes for a wide range of uses.
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Rubber Adhesives and Sealants
Rubber adhesives and sealants are highly flexible, natural or synthetic materials that are used to join components or fill gaps between seams or on surfaces.
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Thermal Compounds and Thermal Interface Materials
Thermal compounds and thermal interface materials form a thermally conductive layer on a substrate, between components or within a finished product.
