Hot Melt News

Most hot melt pressure sensitive adhesives (HMPSAs) are designed or developed for use at room temperature or in an air conditioned environment. A HMPSA exhibits excellent room temperature pressure sensitive adhesion, such as peel and tack, but may show insufficient or non-acceptable performance at sub-ambient or low temperatures. If good adhesion performances at both room and low temperatures are required, can HMPSA formulators develop optimum products to satisfy this requirement? Read Article >>

Room temperature and low temperature performance of HMPSAs - by Pierce Covert, Glue Machinery Corporation

Almost all Hot Melt Pressure Sensitive Adhesives (HMPSA) are composed of various Styrenic Block Copolymers (SBC), tackifiers, and mineral oils. The mixture is a thermoplastic material which does not crosslink or cure during manufacturing and processing.

When a HMPSA is used to bond onto plasticized PVC objects, the pressure sensitive adhesion, particularly the holding power, will deteriorate gradually. PVC alone is a polar and rigid material without any low molecular weight ingredients. It will not affect the performance of any HMPSAs. However, when PVC is plasticized by certain plasticizer, e.g. phthalates, it is softened and flexible. The plasticized PVC becomes a diverse and very useful material… Read Article >>

Hot Melt Pressure Sensitive Adhesion to PVC Materials - by Pierce Covert, Glue Machinery Corporation

Synthetic chemicals are used in most pressure sensitive hot melt adhesives. Lower cost synthetic components are being substituted for higher cost synthetic materials by adhesive manufacturers to insure the availability and consistent pricing of hot melt pressure sensitives. Some manufacturers are claiming incorrectly that they are switching to “Synthetic” materials… Read Article >>

Synthetic Hot Melt Pressure Sensitive Adhesive - by Pierce Covert, Glue Machinery Corporation

… Though the Hildebrand Solubility Parameter is a very useful guideline for selecting compatible raw materials, adhesive formulators always need to blend SBCs and tackifiers together before they can actually observe the degree of compatibility for blends. Theoretically, most SBC-tackifier blends are neither fully compatible nor fully incompatible… Read Complete Article >>

Hot Melt Pressure Sensitive Compatibility of Styrenic Blok Copolymers (SBCs) and Tackifiers - by Pierce Covert, Glue Machinery Corporation

Three major pressure sensitive adhesion performances are determined and reported for all hot melt pressure sensitive adhesives (HMPSAs). They are peel (typically 180°-peel), tack, and shear (or holding power). Sometimes, the heat resistance, Shear Adhesion Fail Temperature (SAFT), and cold resistance are also requested for specific applications. These standard test methods are available form ASTM, PSTC, TLMI, FINAT, and AFREA, etc. Although most lab technicians may follow test procedures according to those test methods… Read Article >>

Factors that Affect Pressure Sensitive Hot Melt Adhesive adhesion performances and values - by Pierce Covert, Glue Machinery Corporation

Although conventional HMA and HMPSA have several advantages, they can not replace cross-linkable solvent and water borne adhesives in some application markets. HMA and HMPSA have two major shortcomings… Plus: Alternatives to conventional hot melt adhesives
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Limitations of Conventional hot melt adhesives and hot melt pressure sensitive adhesives - by Pierce Covert, Glue Machinery Corporation

Pressure sensitive is a term commonly used to designate a distinct category of adhesive tapes and adhesives which in dry form (solvent / water free) are aggressively and permanently tacky at room temperature. Though pressure sensitive adhesives are made and applied daily worldwide, very few people really understand why they are so sticky. Read Article >>

What is a Hot Melt Pressure Sensitive Adhesive and Why are PSA’s Tacky? - by Pierce Covert, Glue Machinery Corp.

Sometimes manufacturers request a particular hot melt color or clarity. Where does the color come from? Why are some adhesives more transparent than others? Does color and clarity mean quality? Why do customers like light colored and transparent adhesives? Read complete article >>

Color and Clarity of Hot Melt Adhesives - by Pierce Covert, Glue Machinery Corp.

Most hot melt adhesive users believe that the value of “viscosity” is an important parameter to various application techniques. The truth is that viscosity in hot melt manufacturing is simply an indicator to determine the consistency between produced batches or lots. In other words, viscosity is simply useful for quality assurance (QA) and quality control (QC). Viscosity variances are the easiest way to determine that your adhesive is not the same product. Read Complete Article >>

Hot Melt Viscosity vs. Viscoelasticity - by Pierce Covert, Glue Machinery Corporation