Sealants are generally chosen for their ability to fill gaps, resist relative movement of the substrates, and exclude or contain another material. Sealants are generally lower in strength than adhesives, but have better flexibility. Usually, a sealant must effectively bond to a substrate in order to perform these functions.
Substrates with reactive groups available for bonding make chemical bonding easier to achieve, while substrates with nothing to react to make adhesion difficult.
October 1, 2005
Adhesive technology is equal parts chemistry and "black magic." The sheer number of available substrates makes it nearly impossible to test each adhesive on every type. However, by conducting tests on a selection of novel, or difficult-to-adhere-to, substrates, we can make inferences that may help narrow the choice of adhesives.
Pressure-sensitive adhesives (PSAs) are a combination of several materials that come together to form a "construction." A PSA construction is a combination of layers including a facestock (label) or backing (tape), an optional primer coat, an adhesive, and a silicone release coating on a protective liner. The PSA construction—whether a label, tape or transfer adhesive—is manufactured through several coating and laminating steps, including liner-release coating, adhesive coating/drying/curing, optional facestock or backing primer coating, and lamination of the facestock or backing to the liner.
Increasing alternatives to mechanical fastening are available.
September 1, 2004
With ongoing advances in structural adhesive formulation, designers in every industry have increasing alternatives to mechanical fasteners for assembly of metal, composites, plastics, rubber, glass and more.
Every single design consideration—including the adhesives selected—is important in the costly endeavor to send an object into space.
October 28, 2003
The harsh conditions of space place a set of constraints on the technologies that take us there. Of primary concern when it comes to space system design is the adhesive chosen to hold everything together. What does it take to perform in the vacuum of space, and why do silicone adhesives continue to be the adhesive of choice in many aerospace applications?
Water-based adhesive systems make inroads into traditional solventborne technology.
March 4, 2003
Contact adhesives based on polychloroprene exhibit performance advantages over alternative adhesive systems in a variety of related applications where quick, high-strength, permanent bonds are needed.
Analytical tools are now available to engineers and product designers challenged with the task of reducing the radiated noise and vibration levels of structures.
The radiated noise and vibration characteristics of manufactured goods are a common concern for most product designers as they strive to provide products that are "whisper quiet."
Standards are an important aspect of your business. If you manufacture, purchase, or use sealants or if you supply raw materials for sealants, your company relies on standards every day. R&D uses test methods and specifications to characterize, compare and develop products. Marketing and Sales use these same standards to advertise and promote products. When materials or sealants are purchased, they must comply with specifications.