Melt glue

Presented here are only the methods that the author has tested in practice on plastics wastes. The first attempts were undertaken in 1986 in a small pilot unit that dealt with wastes of polyolefin films used for packaging. Those wastes were nonpigmented, transparent and rather clean. They were provided by waste collectors in blocks of approximately 30 kg, intended for factories producing regenerated granules (recyclate). The intention was to show the potential of producing a polyolefin wax to be used in polish applications or in hot-melt glues from those wastes. 

In using a bottom load case packer for a packaging operation, the containers are accumulated and unitized into the selected case pattern. As the unitized load is indexed onto the lift platform, a case blank is unfolded from the case magazine over the product. The lift platform raises the product into the opened case. The case is indexed out of the loading area and is top and bottom sealed by a hot melt glue system. The bottom load case packer is the best type of case packer for containers that require stacking, pads, or automatic case insertion. 

Animal base skin, bones, leather, fish and casein glue (most important glue for bottle labelling), glutin hot-melt glue. 

Cartridge type filters are operated at relatively low hydrostatic pressures. Their useful life is limited due to plugging of the membrane pores by retained solutes. The actual cartridge is made by pleating a membrane sheet and potting the ends by an appropriate resin or hot-melt-glue as indicated in Figure 1.33 (a). 

Lastly, some glues harden, at least in part, by congealing or freezing as they cool. Such glues are often called hot melts . Older examples of hot melts include the hot applied resins and waxes and, to some extent, the hot animal glues. Synthetic polymer hot-melt glues have recently become widely used in industry and may have conservation applications as well. 

Plant Resin Formulations, Sometimes compounded with shellac, as in DeKhotinsky cement, these compounds have long been used as hot-melt glues. Likewise, waxes of plant and animal origin have also been used as hot-melt adhesives (22). They all should be reversible by application of heat, possibly in conjunction with solvent action in the more diflScult cases. 

Styrene-butadiene-styrene Solvent-based and hot-melt glues... 

These materials are cut out as various parts, which are then assembled and stuck together with hot melt glue, thus creating the final shape of the casting, also taking into consideration any possible shrinkage of the metal. 

Three kinds of glues or adhesives can be distinguished melt glues, solution glues, and polymerization glues. Elastomers, elastoplasts, or thermosets may be used in all three kinds. 

Melt glues are amorphous and/or partially crystalline polymers above their glass transition temperatures or melt temperatures. Their viscosities should not be too high so that they can wet surfaces well, and not too low so that they do not flow away from where they are applied. Best results are obtained for viscosities of about 10-1 000 Pa s. Poly(ethylenes), poly(ethylene-co-vinyl acetate), poly(vinyl butyrals), versamides, polyamides, aromatic copolyesters, polyurethanes, bitumens, and asphalts, for example, are used as melt glues. The adhesive effect is produced by solidification of the melt glue. 

Adsorption, on the other hand, increases with an increasing number of contact points per adhesive molecules, i.e., with higher molar mass. The adhesion should therefore exhibit an optimum value at a given molar mass of the melt glue. A small number of branches per molecule of adhesive lowers its melt viscosity and consequently increases the rate of diffusion. In the case of very highly branched molecules, on the other hand, fewer contact points can be formed per molecule of adhesive, so that adhesion should also pass through a maximum as branching increases. 

Melt glues are used above their melting or glass-transition temperatures. They are used, for example, in the textile industry to bond cover and support materials. Poly(ethylene), poly(ethylene-co-vinyl acetate), and terpolyamides are typical melt glues. 

When the manufacture of the soap is complete, it has the consistence and tenacity, or closeness of melted glue. It is now allowed to cool down, and is afterwards cleansed or framed in the usual way. The potash ley is employed with the soda ley only for the finer qualities of soap. 

Electric hot-melt glue gun with sticks of adhesive. 

---