Solid Thermoplastics

There seem to be only limited published studies of calcium carbonate s influence on the mechanical properties of thermoplastics and elastomers. Clearly, the Young s modulus and tensile strength are increased. H. Kim et al. [98] showed the addition of calcium carbonate into polypropylene, poly(propylene-random ethylene) copolymer, and poly( propylene-ethylene-butene) terpolymer increases Young s modulus and decreases elongation to break. Kwon et al. [99] observed the same trend for high-density polyethylene, low-density polypropylene, and linear low-density polyethylene compounds that tensile stress of calcium carbonate-filled compounds were higher than unfilled systems. 

Suetsugu [100] studied the tensile strength and the impact strength of polypropylene-calcium carbonate compounds and found it to be dominated by the dispersion of the agglomerate. He defined a dispersion index by 

As described in Section 7.2, stearic acid is often added commercially to calcium carbonate compounds to break up agglomerates and reduce viscosity. It presumably increases tensile strength and impact strength. 

---

Hot melts are 100% solid thermoplastic compounds. They are compounded and applied in the molten state at elevated temperatures. The resultant properties are obtained by cooling. Due to the quick cooling, bonds can be established in a very short time. 

This dosage form will be most familiar to the pharmacist since it is used for companion animals (dogs and cats) and is sold in most drugstores, supermarkets, and animal health product centers. There are two types of flea and tick collars, also known as slow-release pesticide generators vaporous and powder-producing collars. Both contain the insecticide and a plasticized solid thermoplastic resin. 

An interesting development initiated by Neste and Norsk Hydro is a multilayer coating for the insulation of deep-water pipelines. The steel pipe is protected by a layer of solid thermoplastic, a core of polypropylene foam and a coating of solid plastic, all of which are built up by cross head extrusion. 

Finally, a new aluminum fire-resistant paneling consists of a composite design that includes a solid thermoplastic compound core covered with a high density polyethylene adhesive film and an aluminum skin. The product is easily formable. It has sound deadening abilities, and an optional poly(vinyhdene fluoride) resin coating provides damage resistance. 

Terpene Resin, Natural, occurs as a pale yellow to yellow, solid, thermoplastic resin. It is a natural terpene occurring in some coal seams. 

Terpene Resin, Synthetic, occurs as a pale yellow to yellow, solid, thermoplastic resin. It is composed essentially of a-pinene, (3-pinene, and/or dipentene polymers. Its color is less than 4 on the Gardner scale (measured in 50% mineral spirit solution). It is insoluble in water. 

The properties of block copolymers differ from those of a blend of the correponding homopolymers or a random copolymer (Chapter 7) with the same overall composition. An important practical example is the ABA-type styrene/butadiene/styrene triblock copolymer. These behave as thermoplastic elastomers. Ordinary elastomers are cross-linked by covalent bonds, e.g., vulcanization (see Chapter 2) to impart elastic recovery property, as without this there will be permanent deformation. Such cross-linked rubbers are therraosets and so cannot be softened and reshaped by molding. However, solid thermoplastic styrene/butadiene/styrene triblock elastomers can be resoftened and remolded. This can be explained as follows. At room temperature, the triblock elastomers consist of glassy, rigid, polystyrene domains... 

Hot melts are 100% solid thermoplastic materials that are supplied in pellet, slug, block, or irregular-shaped chip form. They require heating via appropriate application equipment, which usually is fairly sophisticated in order to control the required temperature and coverage rate. Upon application, the heat source is removed and the thermoplastics set immediately (within a few seconds). Hot melts are thus well suited to high-speed continuous-bonding operations. 

More than 60 years later, we see the first preparation of polyethylene by Prof. Marvel, a discovery that languished, and then 3 years later, the serendipitous discovery of (solid) thermoplastic polyethylene in 1933, in the research laboratories of ICI, and its commercial production by 1938. 

Features Solid thermoplastic broad solubility and compatibility hard, tough films with gloss, scuff resistance, and durability Properties Beads sp.gr. 1.04 vise. 3000 cps (40% Varsol 3) R B soften, pt. 172 C Sward hardness 58 (7 days) 98% NV NeoCryl B-723 [NeoResins]... 

Features Solid thermoplastic water resistant upgrades color, durability of sol n. vinyls... 

Uses Vehicle, film-former in clear or pigmented coatings for metal, wood, masonry, plastics, and fabrics modifier to upgrade NC and vinyls Features Aids drying time, durability, and color retention solid thermoplastic acrylic... 

Table 3.4 Solubility of solid thermoplastic acrylic resins...

There are three general classes of adhesives. These are hot melt adhesives (HMA), pressure sensitive adhesives (PSA), and hot melt pressure sensitive adhesives (HMPSA). A HMA is a 100 % solids, thermoplastic composition which is compounded and applied molten at elevated temperatures and whose strength is obtained solely by the removal of heat. A PSA is a viscoelastic material which is permanently tacky at room temperature, such that a low force contact to a surface will cause the material to adhere instantaneously. A HMPSA is a viscoelastic material which is permanently tacky at room temperature and which is applied as a 100 % solids, thermoplastic composition in the molten state. Solvent based systems are the oldest technology. Water based systems have the advantage that they avoid flammability and generally do not give off obnoxious odors. Basic adhesive components within each of the three classes are ... 

Thermoplastic adhesives do not cross-link during cure, so they can be resoftened with heat. They are single-component systems that harden upon cooling from a melt or by evaporation of a solvent or water vehicle. Hot-melt adhesives commonly used in packaging are examples of a solid thermoplastic material that is applied in a molten state, and adhesion develops as the melt solidifies during cooling. Wood glues are thermoplastic emulsions that are a common household item. They harden by evaporation of water from the emulsion. 

Extrusion is a polymer conversion operation in which a solid thermoplastic material is melted or softened, forced through an orifice (die) of the desired cross section, and cooled. The process is used for compounding plastics and for the production of tubes, pipes, sheet, film, wire coating, and profiles. All extrusion lines include a melt pump called an extruder, but other equipment is specific to the particular process. Although there are many types of extruders, - the most... 

---