Polypropylene weld strength

Table 20.4 The Effect of Laser Treatment Conditions on Polypropylene Weld Strength Obtained Using Ultrasonic Weld Conditions of 210 N Trigger Force, 2.6 s Ultrasonic On-Time, and 60 KPa Clamping Pressure [123]...

Sancaktar E, Walker E (2004) Effects of calcium carbonate, talc, mica, and glass-fiber fillers on the ultrasonic weld strength of polypropylene. J Appl Polym Sci 94 1986... 

Lin, T. T., and Benatar, A., Effects of Hot Plate Welding Parameters on the Weld Strength of Polypropylene,. ffVTEC Conf. Proc., Soc. Plastics Eng., 1993. 

Three common materials with differing compositions provide a broad range of comparison. 33% Glass filled nylon (GF PA) with 0.15% carbon black, clear polycarbonate (PC), and polypropylene (PP) with red colorant comprise the materials used in this analysis. The behavior of these three materials is well known in vibration welding and hotplate welding. It is not clear how the visual opacity may affect weld strength. 

Recendy, storm doors have been constmcted of advanced thermoplastic composites. Stampable, glass-mat reinforced polypropylene sheet is used to create a high strength outer skin. These compression molded skins are welded together using a friction or ultrasonic process then injection molded with a polyurethane foam core to produce an insulated structure. New technology for window frames incorporate the pultrusion of frame channels to produce a thermoset composite channel that can be filled with fiber glass for further insulation enhancement (12,31,33,34,48,49,54—56,60—67). 

Ghaffin, K. A., J. S. Knutsen, P. Brant, and P. S. Bates. 2000. High-strength welds in metallocene polypropylene/polyethylene laminates. Science 288 2187-2190. 

An important application for polybntylene is plumbing pipe for both coimnercial and residential use. The exceUent creep resistance of polybntylene aUows for the manufacture of thiimer wall pipes compared to pipes made from polyethylene or polypropylene. Polybutylene pipe can also be used for the transport of abrasive fluids. Other applications for polybutylene include hot melt adhesives and additives for other plastics. The addition of polybutylene improves the environmental stress cracking resistance of polyethylene and the impact and weld line strength of polypropylene. Polybntylene is also used in pack aging applications. 

High-density polyethylene, HDPE, was blended with 50 wt% polypropylene, PP, having matched melt flow index, to give good flowability, weld-line strength, surface quality, and low-temperature impact strength... 

The multiple functions of mica have been outlined in Chapter 1 of this book, along with an example of its role in the search of multifunctional fillers for polypropylene compounds for automotive applications. Mica-reinforced thermoplastics such as polypropylene, polyethylene, nylon, and polyesters are now established in a variety of automotive applications and consumer products where mica supplements or replaces glass fibers and other mineral fillers. The wider use of mica in many applications has been limited by low impact strength and low weld-line strength in certain plastics. These issues are the focus of continuing R D efforts by materials suppliers and compounders/molders. 

Other applications include hot-melt adhesives and additives for other plastics. The addition of polybutylene improves the environmental stress cracking resistance of polyethylene and the impact and weld line strength of polypropylene. Polybutylene is also used in packaging applications. 

Figure 18.41 The effect of weld lines on the falling weight impact strength of polypropylene copolymer at 23 °C. Source Author s own files)...

Seldon et al. [96] measnred weld line impart strength and tensile strengths on mjertion-molded specimens of fiberglass-reinforced polyamide 6 and talc-reinforced polypropylene. The effect of hold pressure, impart velocity, melt temperature, and mold tanperature on weld line strength was studied. 

Seldon [10] measured the weld line strength and impact, and flexural and tensile properties of injection-molded specimens of glass fiber-reinforced polyamide 6 and talc-filled polypropylene (PP). Further information was obtained by examination of fracture surfaces by scanning electron microscopy. 

One data set of the vibration process does not show expected or desirable results. The vibration weld of polypropylene parts does not demonstrate a strong weld as compared with the hotplate or IR samples. Nor does it show good strength as compared widi its own parent material strength. While it is known that PP achieves only -80% of parent material strength with VW, this data does not follow. Results are 1.00 MPa or 57% of parent material. More samples should be welded to verify the PP data. 

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