Glass mat thermoplastic

The efficiency with which the sheet can be cut to produce blanks with minimum wastage is a key feature in GMT molding (though, since it is a TP matrix, it is possible easily to re-use/recycle off-cut material). It also lends itself to automation, placing the hot blanks in the open press by robot. 

A GMT material called SymaLITE offers 20% to 50% better mechanical properties than other GMT materials. Its first commercial use was in underbody panels formed by processor Seeber Systemtechnik (Worms, 

Tensile strength Tensile modulus Flexural strength Flexural modulus Charpy impact (unnotched) Coefficient of linear thermal expansion Heat distortion 

A direct competitor is SuperLite GMT, supplied since 1999 by Azdel (headquarters Shelby, NC, USA), a 50/50 joint venture of glass fiber supplier PPG and engineering TPs supplier GE Plastics. Azdel markets its material for many of the same applications as QPC now hopes to, and in the last two years has doubled SuperLite capacity at its Lynchburg, VA site. Demand for the product is growing at a pace that may soon justify European production. Like the QPC material, low molding pressures are used, and cycle times typically are less than one minute. 

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Composite processing uses specialized methods. For thermoplastics, glass mat thermoplastic (GMT) is the main method but prepreg, lay-up, tape winding, pultrusion are also used to produce composites. SMC/BMC are the main processes for thermosets but lay-up is currently used for large parts and prepregs are used for high-tech parts. 

Table 6.36 displays basic property examples of glass mat thermoplastics (GMT) thermoplastic prepregs and glass or carbon reinforced unidirectional composites. 

Use of structural plastics long fibre reinforced thermoplastics (LFRT), glass mat thermoplastics (GMT), thermoplastic sandwich structures, carbon fibre reinforced thermoplastics. 

Glass Eibre Reinforced Plastic Glass Mat Thermoplastic UL fire rating High Density PolyEthylene Heat Deflection Temperature... 

All PP Composites Could Challenge GMT (Glass-Mat-Thermoplastic) in Markets, MP, June 2003. 

UD, unidirectional GMT, glass mat thermoplastic TMC, thick molding compound SMC, sheet molding compound. (From Refs. - . )... 

With RTFs, the technical difficulty of mixing the plastic matrix with reinforcement such as glass fiber has made it standard practice for materials suppliers to offer a reinforced molding compound that is ready formulated with all the necessary ingredients, with the possible exception of pigment. A ready-made RTP in sheet form is also available, known as glass mat thermoplastic (GMT). 

Analogous also to TS SMCs and BMCs are TP molding compoimds in sheet form, known as glass mat thermoplastics (GMTs), and compoimded into standard granules for injection molding and extrusion. Most TPs are capable of combination with reinforcement. The main types used commercially are PA and PP. 

Figure 4.4 Basic system for production of glass mat thermoplastics...

Stamped glass mat thermoplastic (GMT) parts will also require trimming, which (due to volume of production) can usually be automated by robot or similar system. 

Glass Mat Thermoplastics, Basic/mechanical/thermal properties... 

What a particular letter stands for sometimes depends on the context as individual letters can have more than one meaning, for example, M when used in GMT it stands for mat and so, GMT stands for a glass mat thermoplastics material. Because of the growth of oriented plastics products, the letter O is put in front the abbreviation for a particular material so, oriented PVC becomes OPVC this means that a container is made fi om that oriented material. 

The joint venture between General Electric and PPG in 1986 to form the Azdel Corporation has created a unique composite market of its own. The most publicized application is for bumper beams (198). Azdel composite sheets were first introduced in the Corvette bumper system in 1984. Honda began to use it on the 1990 models (199). In 1992, the worldwide sales of glass mat thermoplastic was projected to be over 60,000 tons (200). Half of the sales were in the United States (32,700 tons). European sales, at 15,400 tons, were slightly more than that in Japan at 12,000 tons. In addition, Europe and especially Japan were projected to experience higher growth rate than the United States. 

HF Giles, Jr. Reducing shrinkage and warpage in glass-mat thermoplastic composite. Plastic Eng LII(9) 43-45, 1996. 

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