Melt compression molding

Melt compression molding identifies in-mold laminating and in-line molding of carriers, decorations, etc. The basic technique has been used for over a century. There has been an increased application of textile cover stock and leather substitutes both preferably with a soft touch. This type development was primarily initiated by the automotive industry with the objective to be prepared for future trends. Other industries such as furniture and packaging manufacturers use this process. 

Figure 22.14 Stress-strain curves, recorded at room temperature of melt-compression-molded films of poly(butyloxy-pora-meftl-phenylene) (PBmP) (55) (high-molar-mass part). For reference purposes, corresponding curves of a-PS, PMMA, and PC are also shown, illustrating the excellent mechanical properties of...

Figure 1. DMTA scans of slowly cooled, melt compression-molded PEBAX films (a) storage modulus, (b) tan 6. TVansitions are numbered 1 to 5, transitions 4 and 5 being indicated by a general range of temperatures [22]...

Figure 12. Strain-induced crystallization of slowly cooled, melt compression-molded P2533 and P3533 (a) WAXS images of samples stretched to a draw ratio of 8 x, (b) DSC thermal scans of freely relaxed samples (traces displaced vertically for clarity), and (c) WAXS images of freely relaxed samples annealed at 70°C for 90 min. Annealed samples P2533 and P3533 exhibited a permanent set of 63% and 97%, respectively, when measurements were made immediately after cooling of the annealed samples to room temperature. Stretch direction in WAXS patterns is vertical [22]...

By contrast with ICM, a compression mold design is used where male plug fits into a female cavity rather than the usual flat surface parting line mold halves for IM (Fig. 8-27). The melt is injected into the cavity as a short shot thereby not filling the cavity. The melt in the cavity is literally stress-free it is literally poured into the cavity. Prior to receiving melt, the mold is slightly opened so that a closed cavity exists the male and female parts... 

Most of the compounds were extrusion compounded in a conical, partially intermeshing, counter rotating twin screw extruder (Haake Reomix TW-lOO). The extruder speed was set at 50 rpm and the barrel temperature profile was set to produce a melt temperature of 260°C at the die. Samples were injection molded in a 31.8 MT Battenfeld press with a 59 cc shot size. Where noted, samples were compounded in a 60 cc Brabender internal mixer and compression molded. 

Samples of /the polymers for physical evaluation were prepared by film casting from toluene solution at 90°C. and allowing the crystallization to occur by cooling the melt. It was observed that phase separation occurred in the melt in the case of the H2-BIB but not for the H2-BBB. These materials could also be compression molded at 1<40°C., but optimum results appeared to be obtained with the film-cast samples. 

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