Laminate Thermoplastic

Very popular is plastic cushioning material used in packaging, usually laminated thermoplastic films that incorporate air bubble pockets. 

Barnes, J.A. and Byerly, G.E. (1994). The formation of residual stresses in laminated thermoplastic composites. Composites Sci. Techno . 51, 479-494. 

An important step in the manufacture of any plastic product is the fabrication or the shaping of the article. Most polymers used as plastics when manufactured are prepared in pellet form as they are expelled from the reactor. These are small pieces of material a couple of millimeters in size. This resin can then be heated and shaped by one of several methods. Thermoset materials are usually compression molded, cast, or laminated. Thermoplastic resins can be injection molded, extruded, or blow molded most commonly, with vacuum forming and calendering also used but to a lesser extent. 

In recent years postforming compact laminates (typically, 2 to 10 mm thick) have been developed, using within the laminate thermoplastic films to act as slip layers. These products require special techniques for forming. 

Mouth PrOtOCtOrS. The widespread growth of contact sports has accelerated the use of mouth guards (34,35). Guards may be produced from natural rubber, poly(vinyl chloride), poly(vinyl acetate-co-ethylene), or polyurethane materials. Customized guards are often fabricated from poly(vinyl acetate-co-ethylene) blanks, soft acrylic dough, liquid rubber latex, polyurethane, and laminated thermoplastic (36,37). Over the counter protectors usually fit poorly, in contrast to dimensionally stable and comfortable, customized mouth protectors. 

A confinement technique using non-laminated thermoplastic CFRP straps was investigated and applied to 2 m high RC columns. The results from tests were encouraging, although practical and theoretical problems remain to be solved before these techniques can be applied in practice (Motavalli et al., 2011). 

Lamination-Type Adhesiveless Laminates. Thermoplastic-type polyimide resins... 

Thermosetting polyimides are commercially available as uncured resins, thin sheets, and laminates. Thermoplastic polyimides are very often called pseudothermoplastic. There are two general types of polyimides. One type is linear polyimides which are made by combining imides into long chains. Aromatic heterocyclic polyimides are the other usual kind, where R and R" are two carbon atoms of an aromatic ring. Examples of polyimide films include Apical, Kapton, and Kaptrex. Polyimide parts and shapes include Meldin, Vespel, and Plavis. Polyimides have been in mass production since 1955. 

As a tme thermoplastic, FEP copolymer can be melt-processed by extmsion and compression, injection, and blow molding. Films can be heat-bonded and sealed, vacuum-formed, and laminated to various substrates. Chemical inertness and corrosion resistance make FEP highly suitable for chemical services its dielectric and insulating properties favor it for electrical and electronic service and its low frictional properties, mechanical toughness, thermal stabiUty, and nonstick quaUty make it highly suitable for bearings and seals, high temperature components, and nonstick surfaces. 

Polyester. Poly(ethylene terephthalate) [25038-59-9] (PET) polyester film has intermediate gas- and water- vapor barrier properties, very high tensile and impact strengths, and high temperature resistance (see Polyesters, thermoplastic). AppHcations include use as an outer web in laminations to protect aluminum foil. It is coated with PVDC to function as the flat or sealing web for vacuum/gas flush packaged processed meat, cheese, or fresh pasta. 

Free mono- and multilayer films may be adhesive- or extmsion-bonded in the laminating process. The bonding adhesive may be water- or solvent-based. Alternatively, a temperature-dependent polymer-based adhesive without solvent may be heated and set by cooling. In extmsion lamination, a film of a thermoplastic such as polyethylene is extmded as a bond between the two flat materials, which are brought together between a chilled and backup roU. 

Unsaturated resias based on 1,4-cyclohexanedimethanol are useful ia gel coats and ia laminating and molding resias where advantage is taken of the properties of very low water absorption and resistance to boiling water (6). Thermal stabiHty is imparted to molding resias, both thermoplastic (71,72) and thermoset (73—76), enabling retention of physical and electrical properties at elevated temperatures (77). Additionally, resistance to chemical and environmental exposure is characteristic of products made from these resias (78). 

Although it would be desirable to recycle laminate scrap, this has been difficult because of its thermoset nature. However, a 1993 patent (18) suggested a means whereby scrap consisting of cellulose, thermoset resins, and partially reacted resins can be ground to a powder which is used as a filler in a thermoplastic resin. The filled thermoplastic resin is then used for mol ding of various articles. 

Early phenoHc resins consisted of self-curing, resole-type products made with excess formaldehyde, and novolaks, which are thermoplastic in nature and require a hardener. The early products produced by General BakeHte were used in molded parts, insulating varnishes, laminated sheets, and industrial coatings. These areas stiH remain important appHcations, but have been joined by numerous others such as wood bonding, fiber bonding, and plywood adhesives. The number of producers in the 1990s is approximately 20 in the United States and over 60 worldwide. 

The first commercial grades were introduced by Phillips Petroleum in 1968 under the trade name Ryton. These were of two types, a thermoplastic branched polymer of very high viscosity which was processed by PTFE-type processes and an initially linear polymer which could be processed by compression moulding, including laminating with glass fibre, and which was subsequently oxidatively cross-linked. 

Some typical properties of polyester-glass laminates are given in Table 25.1. From these figures it will be seen that laminates can have very high tensile strengths. On the other hand some laminates made by hand lay-up processes may have mechanical properties not very different from those of thermoplastics such as the polyacetals and unplasticised PVC. 

Shoe adhesives. CR adhesives are used for the permanent attachment of shoe soles. For difficult-to-bond sole materials (plasticized PVC, EVA foaming soles, thermoplastic rubber, SBR) graft polymer solutions of Neoprene AD-G combined with a polyisocyanate provide a good adhesion. Another major area for CR contact adhesives is the manufacture of leather goods, particularly leather shoe sole bonding and belt lamination. 

The market for polyurethane thermoplastic adhesives is small, but growing. TPU s are used to produce some solvent-borne adhesives and also are used in laminating textiles and films for labels and emblems. In addition, they are being considered as an alternative to solvent-borne adhesives in the shoe market. 

---