Hot-melt adhesives are as numerous as they are versatile. Generally speaking, hot melts are applied by extruding, rolling or spraying, as well as the high melt viscosity makes them suitable for porous and permeable substrates. HMA are capable of bonding a multitude of different substrates including: rubbers, ceramics, metals, plastics, glass and wood.
Today, HMA (hot-melt adhesives) are available in a selection of different types, making it possible for use in a wide range of applications across several industries. To be used with hobby or craft projects including the assembly or repair of remote device foam model aircraft, and artificial floral arrangements, hot-melt sticks and hot-melt glue guns are utilized in the use of the Double Sided Fusible Interfacing. To be used in industrial processes, adhesive is supplied in larger sticks and glue guns with higher melting rates. Aside from hot melt sticks, HMA may be delivered in other formats including granular or power hot melt blocks for bulk melt processors. Larger applications of HMA traditionally use pneumatic systems to supply adhesive.
Samples of industries where HMA is used includes: Closing the flaps of corrugated boxes and paperboard cartons inside the packaging industry. Spine gluing in the bookbinding industry. Profile-wrapping, product assembly and laminating applications in the woodworking industry. Disposable diapers are constructed through the use of HMA, bonding the non-woven material to the backsheet and the elastics. Many electronic device manufacturers may also use an HMA to affix parts and wires. or even to secure, insulate, and protect the device’s components
Sometimes manufacturers request a certain hot melt color or clarity. Where does the colour come from? Why are some adhesives more transparent than others? Does color and clarity mean quality? So why do customers like light colored and transparent adhesives?
All materials in this particular universe, when their electrons are excited by certain energy, may emit a wavelength showing different colors. These colors are observed by human eyes or detected by instruments. Most polymeric materials containing more polar functional groups or double or triple bonds, have a tendency to generate colorful bodies. Because of this, whenever a hot melt formulation contains more polar ingredients, such as non-hydrogenated hydrocarbons resins and natural rosin along with its derivatives, these are normally darker compared to those hydrogenated ingredients.
Disregarding color, when the ingredients used in a hot melt formulation are extremely compatible, having similar solubility parameters, the formulated product will be clear or transparent. On the contrary, to get a less compatible and Hot Melt Adhesive Film for Textile Fabric, the appearance is cloudy or opaque.
Clarity will not be a huge concern for many applications. However, the warmth stability for anyone cloudy and opaque formulations can be relatively poor in comparison to some clear formulations. Incompatible ingredients in the formulation tend to separate far from the other person upon heating at elevated temperatures because of the widely different solubility parameters. Remember that the above mentioned cloudy and opaque appearance does not apply to those materials with crystalline such as wax and ethylene segment of Ethylene Vinyl Acetates (EVA).
Many users, especially in the Asian countries, often ask for water white and clear HMPSAs for many applications simply due to esthetics reason. Consequently, water white, hydrogenated tackifying resins are essential for those formulations. All selected ingredients must be compatible also. Inside the principle of adhesion, a much more polar adhesive caarow generates better adhesion to substrates due to its higher surface energy. Quite simply, your selection of more expensive water white ingredients for esthetic purpose may adversely hurt adhesive performance. To compensate the loss of portion intrinsic adhesion resulted from lower surface energy; adhesives rheology will then be becoming an important factor affecting adhesion performances. The rheology or mechanical property of adhesives will be discussed in a separate article.
Indeed, aside from the esthetic reason, clear Shape Flex SF101 Alternative exhibit much better heat stability and pot life when they are heated at elevated temperatures for a long time of your time. This is very important particularly for your process employing an open coating system, such as a roll coating line.