Hot Melt News

It may sound odd to discuss the topic of “How to make a consistent hot melt pressure sensitive adhesive” if one has a good formulation in hand. Although products may look the same - they are not identical in size, shape, and weight. Molecular weight (MW), molecular weight distribution (MWD), branching, networking, etc. of each polymerized batch are not always the same. Although HMPSA production does not involve any chemical reaction during mixing, it is simply a blending of several different but compatible ingredients.

Typical HMPSAs are composed of a SBC (Styrenic Block Copolymer), tackifiers, mineral oil, and antioxidants. If formulators and producers carefully read the COA (Certificate of Analysis) of each received ingredient, they may be surprised at the significant deviations between batches or lots received. For example, the specification of MFR (Melt Flow Rate) at 190C for a typical SIS (Styrene-Isoprene-Styrene block copolymer) is 8.0. But the range of this specific…. Read Article >>

How to Make Consistent Hot Melt Pressure Sensitive Adhesives (HMPSA) - by Pierce Covert, Glue Machinery Corporation

The performance requirements for HMPSAs are more complicated than those for EVA and APO-based HMAs. In addition to basic physical properties, such as viscosity and softening point, some pressure sensitive “adhesion performances” should be evaluated. All equipment may honestly reveal certain values determined under different geometries and conditions. No equipment can actually guide formulators or adhesion scientists in the appropriate direction to manipulate the formulation. Trial and error remains the most common way to deal with formulation if those determined values do not meet desired target. Basic equipment and instruments required for a fully functional HMPSA laboratory…. Read Article >>

Evaluation Equipment Required for a Hot Melt Pressure Sensitive Adhesive Lab - by Pierce Covert, Glue Machinery Corporation

Removable, or fugitive, HMPSAs are useful for those applications requiring low peeling force without damaging and leaving adhesive residues on substrates. There is no fixed or targeting peeling force for removable HMPSAs. It is totally dependent upon the fracture energy or tearing strength of bonded substrates.

Technically, it is more difficult to formulate a low peel versus a general purposed (permanent) HMPSA based on commercially available SBCs (Styrenic Block Copolymers). For a removable HMPSA, in addition to the low initial peel, most applications also require very low peel force build-up after aging for a period of time. HMPSAs contain many low molecular weight ingredients which will gradually wet onto porous surfaces and increase the contact area. As a result, the peel force… Read Article >>

Removable - Fugitive Hot Melt Pressure Sensitive Adhesives
- by Pierce Covert, Glue Machinery Corporation

Hot Melt Adhesives (HMAs) were primarily developed for industrial use. They have been, and are now, widely used in many application markets such as: packaging, bookbinding, woodworking, electronics, lamination, shoemaking, craft gluing, hobby work, cabinet making, florist work, upholstery, product assembly, and many other applications. HMAs have also been promoted to home and shop use by providing glue sticks accompanied by simple and light weight glue guns. Several different types of hot melt glue sticks are available in the market. Some typical characteristics of hot melt stick adhesive… Read Article >>

Introduction of Hot Melt Glue Sticks - by Pierce Covert, Glue Machinery Corporation