Adhesion of polypropylene

Similarly, Plueddemann has reported [3c] an optimum silane coupling agent layer thickness of 50-200 A for commercial glass fiber treatment for use in composite materials. On the contrary, optimum adhesion of polypropylene to aluminum was obtained with a silane primer layer between 0.5 and 10 pm thick. In... 

It is quite well known that the formation of nanophases plays an important role in adhesive technology although this fact was ignored for many years due to the difficulties relating to the imaging of such small structures. Nanometer-scale interdiffusion layers account for polymer/polymer adhesion. This is illustrated in Fig. 13.6 for the sandwiched films of the thermoplastic elastomer SEES and isotactic polypropylene, annealed at 160°C for several hours. The interdiffusion layer is approximately 100 nm wide. This interfacial nanodesign is the key to improved adhesion of polypropylene materials. 

Poon, B., Chum, S. R, Hiltner, A., and Baer, E., Adhesion of Polypropylene to Metallocene/ Ziegler-Natta Polyethylene Blends in Microlayers, SPE Technical Papers 1849 (2002). 

NBR latices can be also used in adhesive applications. The use of latex has the advantage of avoiding the previous solution of the polymer before application and has favourable environmental treats. Compounding with a resorcinol-formaldehyde solution allows to bond nitrile rubber to cotton or rayon fabric. Nitrile latex can be mixed with PVC latex to give excellent adhesion of polypropylene carpet and plywood backings. Combinations of nitrile latices and styrene-butadiene latices provides good laminating bonds for saturated paper and woven fabrics. 

A well knoiw method, grafting, has been used to improve adhesion of polypropylene, and polyethylene to metals. Schultz et al. show that the addition of acrylic acid can enhance the adhesion of polyethylene to aluminum. 

Nitrile latex can be mixed with PVC latex to give excellent adhesion of polypropylene carpet and plywood backings. The formulation shown in Table 10 was found to give good adhesion even after seven days immersion in water. 

Zeiler T, Kellermann S, Munstedt H. Different surface treatments to improve the adhesion of polypropylene. J of Adhes Sci and Tech. 2000 14 (5) 619-634. 

The chelated organic titanates also function as adhesion promoters of the ink binder to printed substrates such as plastic films, paper, and aluminum foil (504). The acetylacetone complexes of titanium are the preferred products for promoting adhesion of printing inks to polypropylene films. 

Hypalon CP 826. This is a chloriaated, maleic anhydride modified polypropylene having a chlorine content of about 25% and maleic anhydride content of about 0.8%, developed to promote adhesion of inks and coatiags to polypropyleae or bleads containing polypropyleae. It has a solutioa viscosity of 125 mPas(= cP) at 20% soHds ia xyleae and can be used ia dilute solutioas as a wash primer or a tie layer betweea materials that are difficult to adhere. CP 827 is a higher molecular-weight analogue with a solution viscosity of 280 mPas(= cP) at 20% soHds ia 80/20 xylene/methyl isobutyl ketoae. 

Papirer et al. used ATR, XPS, and SIMS to determine the effect of flame treatment on adhesion of polyethylene and polypropylene to styrene/butadiene (SBR) rubber [8]. Each flame treatment consisted of a 75-ms pass over a circular burner. The distance between the upper flame front and the polymer was kept fixed al 8 mm. A band was observed near 1720 cm" in the ATR spectra and assigned to carbonyl groups this band increased in intensity as the number of flame... 

Godail and Packham [77,78] have applied these ideas to the adhesion of ethylene-octene copolymers laminated to polypropylene. Variations in adhesion energy found with different laminating temperatures were interpreted in terms of... 

Godail, L. and Packham, D.E., Adhesion of ethylene-octene copolymers to polypropylene interfacial structure and mechanical properties. J. Adhes. Sci. Technol., 15, 1285-1304 (2001). 

Butyl latex can be used in packaging and as a tackifying and flexibilizing additive in higher strength adhesives for adhesion of polyethylene and polypropylene. 

Specialty waxes include polar waxes for more polar adhesive systems. Examples would be castor wax (triglyceride of 12-hydroxy stearic acid) or Paracin wax N- 2 hydroxy ethyl)-12-hydroxy stearamide) which are used in polyester, polyamide, or with high VA EVA copolymer-based systems. Other common polar waxes are maleated polyethylenes, which are used to improve the specific adhesion of polyethylene-based adhesives, and low molecular weight ethylene copolymers with vinyl acetate or acrylic acid, which are used to improve low temperature adhesion. High melting point isotactic polypropylene wax (7 155°C) and highly refined paraffin wax (7,n 83°C) are used where maximum heat resistance is critical. Needless to say, these specialty waxes also command a premium price, ranging from 2 to 5 times that of conventional paraffin wax. 

The effect of thermal aging on polyethylene and isotactic polypropylene have been studied by Konar et al. [49]. They used contact angle, contact angle hysteresis, and XPS to characterize the modified surfaces of the polymers. Hysteresis increased with aging temperature. In the case of polyethylene, thermal aging led to a significant increase in adhesion strength of polyethylene with aluminium, but the increase in the case of polypropylene was much less marked. 

Other plastics now being plated on an increasing scale are polypropylene and, to a smaller extent, polysulphone. Polypropylene is considerably cheaper than ABS, and is much more resistant to distortion at elevated temperatures, so that it can be used at up to 150°C as compared with 100°C for ABS the adhesion of the deposits is also superior. 

Adhesion or printability of polymeric surfaces, including films, is often promoted by plasma or glow discharge treatment. In particular for apolar (low surface energy) surfaces such as polyolefins this is a commonly applied procedure. As a practical industrial example, the adhesion behaviour of polypropylenes after... 

It promotes adhesion of intaglio inks to the polypropylene surface. An acrylic based primer is a good choice because of its ability to effectively bond water-based inks. Dry powder form of acrylic primer is diluted with methyl ethyl ketone and xylene (each component is mixed in equal parts by weight). To create the opaque surface, 5wt% titanium dioxide pigment is added to the solution. 

Mahlberg, R., Niemi, H.E.M., Denes, F. and Rowell, R.M. (1998). Effect of oxygen and hexameth-yldisiloxane plasma on morphology, wettability and adhesion properties of polypropylene and lignocellulosics. International Journal of Adhesion and Adhesives, 18(4), 283-297. 

A recent patent by Thomason [15] has revealed that ammonium zirconium carbonate when applied to a substrate such as glass, aluminium, or polypropylene can improve the adhesion of microsphere polymer-based adhesives. It is proposed that the zirconium after reacting with the substrate surface reacts with carboxyl groups at the surface of the polymer microspheres. 

Zirconium propionate is a polymeric zirconium carboxylate its structure is illustrated in Fig. 10. Use of zirconium propionate markedly increases the adhesion of an ink applied to treated polypropylene film. Figure 11 compares zirconium propionate with titanium acetylacetonate, which is commonly regarded as the industry standard. The standard test method used in the ink industry is the so-called tape test . Sticky tape is placed on the printed film and pressure is applied by the operator s thumb. The tape is then pulled off, by hand, and the amount of ink removed is visually assessed. Although extremely crude, it can be, and is, used for control in the ink industry. 

Abstract Polyolefins such as polyethylene, polypropylene and their copolymers have excellent bulk physical/chemical properties, are inexpensive and easy to process. Yet they have not gained considerable importance as speciality materials due to their inert surface. Polyethylene in particular holds a unique status due to its excellent manufacturer- and user-friendly properties. Thus, special surface properties, which polyethylene does not possess, such as printability, hydrophilicity, roughness, lubricity, selective permeability and adhesion of micro-organisms, underscore the need for tailoring the surface of this valuable commodity polymer. The present article reviews some of the existing and emerging techniques of surface modification and characterisation of polyethylene. 

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