A method of producing a hot melt adhesive solid, the method comprising the steps of inserting a hot melt adhesive heated to higher than a flow temperature into a container having a mold-releasing internal surface and a bottom plate which is openable and closable or removably fixable to the container, cooling the hot melt adhesive at least until the surface of hot melt adhesive becomes solidified, and taking out the hot melt adhesive from the container by opening the bottom plate or displacing the same; hot melt adhesive solid; method of packaging the same; and method of transporting the same.

The present inventors have discovered that an easily measured property, namely complex viscosity, directly relates to physical film compatibility and have further identified a class of polyolefin materials, which are particularly amenable to exhibiting such properties. It is important to note that this discovery assumes that the film material is first chemically compatible with the thermoplastic composition to be packaged. The invention is particularly useful for low viscosity thermoplastic compositions having a Brookfield viscosity of less than about 10,000 cPs at 350.degree. F., such as pressure sensitive hot melt adhesive compositions which are typically applied by melting the packaged adhesive composition in a melt tank wherein the melt tank lacks an active mixing means. The invention is also useful for hot melt adhesives that are applied by application means that are very sensitive to inhomogeneity of the combination of molten hot melt adhesive and molten packaging material such as spraying, screen printing, foaming and gravure coating hot melt application techniques.

A dual component molding assembly for packaging hot melt adhesives wherein a mold, preferably in the form of an open top pan, includes a cavity which is lined with a thin film of plastic material. The mold has openings formed therein which communicate with the cavity to facilitate vacuum forming of the film to the cavity's interior surface. The second component is a carrier for the mold and is also preferably in the form of an open top pan. The carrier also includes a cavity for receiving the mold, and functions not only to support the mold when nested therein, but also to act as a heat sink to effectively and rapidly remove, dissipate or absorb the heat from molten adhesive dispensed into the mold. After filling the mold with a mass of adhesive, the exposed open top surface of the adhesive is covered with a second layer of thin film of plastic material which is then sealed to the first film lining the interior of the mold. After cooling, the packaged adhesive is cut adjacent the seal to form individual adhesive blocks for further processing.

A method for packaging in block form a sheathed hot-melt adhesive product comprises the steps: (a) of continuously supplying a sheathed hot-melt adhesive product, (b) of immersing the sheathed hot-melt adhesive product in a liquid refrigerant, (c) of pressing the sheathed adhesive product at a portion thereof, (d) of ultrasonically welding the sheathed adhesive product at the pressed portion; and (e) of cutting the sheathed adhesive product into a block at the pressed portion. A block of sheathed hot-melt adhesive product and an installation for packaging a sheathed hot-melt adhesive product are also provided.

A method for packaging plastic material using a film to surround the material, and more particularly to a method for packaging hot melt adhesives, the resulting package formed thereby, and the film composition used therein. The method is preferably a coextrusion process for packaging a pressure sensitive hot melt adhesive by extruding a hot melt adhesive through a die orifice, and coextruding a wax-based polymeric film to surround the hot melt adhesive. The coated adhesive may then be formed into individual packaged units having a finite size and shape. The polymeric film comprises a composition having at least 25% by weight of a wax material, an enthalpy of fusion of at least about 100 J/g, and an elongation value at break of at least about 100%. Any type of hot melt adhesive formulation can be packaged or surrounded by the polymeric film in the process. Also, the specific enthalpy of fusion desired and/or elongation value at break desired for the polymeric film can be obtained by blending an appropriate amount of partially crystalline ethylene-based polymer together with a thermoplastic elastomeric block copolymer and/or an ethylene based or propylene-based elastomer.