Dyeability, polypropylene

Improved dyeability Polypropylene United States 3,131,990 1964 Montecatini... 

Improved dyeability Polypropylene Japan 19,863 1969 Mitsubishi Rayon Co. 

Improved dyeability Polypropylene Japan 27,579 1971 Mitsubishi Rayon... 

Polyolefins with dyeability Polypropylene Japan 44,186 1978 Mitsui Petrochemical Ind. 

Polyolefins with improved dyeability Polypropylene W. Germany 2,708,757 1979 Idemitsu Ind. 

Polyethylene and polypropylene fibres are both used as fibre-forming for textile purposes. They are widely used in industrial fabrics. These two fibres can be bonded into non-woven fabric form and used as the base for tufted carpeting. Olefin fibres are relatively low in cost, but both the fibres have low melting points, low glass-transition temperatures and poor dyeability. 

There are now polymer products in the market for the dyeability modification of polypropylene. Based on journal reports, Eif-Atochem and Centexbel, both EU firms, have developed polymeric additives that are compatible with polypropylene [157]. These compatible polymers imparted outstanding dyeability to spun fibers with selective dispersion dyestuff. 

There are many options and elegant methods for the dyeability modification of polypropylene fiber. The key to success is the cost, fiber properties, and color durability. With further research and market evaluation, it is quite hopeful that the dyeing problem of polypropylene fiber will be successfully resolved in the near future. 

A recent report by Fan et al. [267] claimed that the incorporation of nanosized clay modified with quaternary ammonium salt in polypropylene imparted dyeability. The technique... 

In summary, there is an impressive amount of research effort on various polypropylene fiber products. The developments of fine-denier spinning, dyeability modification, high fiber strength and modulus, and nanocomposites certainly appear inductive to further growth in market shares and value-in-use for propylene fibers. However, as with other synthetic fibers, the manufacturing process yield and cost, particularly spinning continuity, must not be adversely impacted by any new technology to be commercialized. This is clearly the key to the future success of polypropylene fibers. 

As stated above, conventional synthetic fibres may be rendered inherently flame retardant during production by either incorporation of a flame retardant additive in the polymer melt or solution prior to extrusion or by copolymeric modification before, during, or immediately after processing into filaments or staple fibres. Major problems of compatibility, especially at the high tanperatures used to extrude melt-extruded fibres like polyamide, polyester, and polypropylene and in reactive polymer solutions such as viscose dope and acrylic solutions, have ensured that only a few such fibres are commercially available. A major problem in developing successful inherently flame retardant fibres based on conventional fibre chemistries is that any modification, if present at a concentration much above 10wt% (whether as additive or comonomer), may seriously reduce tensile properties as well as the other desirable textile properties of dyeability, lustre and appearance, and handle, to mention but a few. 

To improve dyeability, flexibility, and toughness of isotactic polypropylene, PP, it was compounded in a Banbury-type mixer with ethylene-vinyl acetate, 7 wt% EVAc. Several other ethylene copolymers were also used. In Miliprint patent, EVAc or ethylene-ethyl acrylate copolymer, 18-32 wt% EVAc or EEA, was found to improve impact strength, elongation, and low brittleness temperature of PP. hi Firestone patent, linear polybutadiene, BR, was used. The Mitsubishi patent disclosed improvements of PP impact strength properties by blending it with 0.5-25 wt% ethylene-aliphatic esters, e.g., EVAc... 

To improve dyeability, flexibility, and toughness of isotactic polypropylene, PP, it was compounded in a Banbury-type mixta with ethylene-vinyl acetate,... 

Polypropylene (PP) is highly apolar material, therefore a modification aimed at the creation of a more polar surface is an important issue considering, for example, wettability, adhesion, barrier properties or dyeability. 

Polyolefins, especially polyethylene and polypropylene, are used in a wide range of applications, since they incorporate an excellent combination of mechanical, chemical and electronic properties and processibility. Nevertheless, deficiencies, such as the lack of reactive groups in the polymer structure, have limited some of their end uses, particularly those in which adhesion, dyeability, paintability, printability or compatibility with other functional polymers is paramount. Accordingly, the chemical modification of polyolefins has been an area of increasing interest as a route to higher value products and various methods of functionalization (1-3) have been employed to alter their chemical and physical properties. 

This same technique has also been used to improve the dyeability of polypropylene fiber, a problem of major commercial importance. Thus, polypropylene has been extruded with copolymer containing polar groups such as a random copolymer made from 93% methyl acrylate and 7% of a sodium alkyl sulfonate or a poly(styrene-co-styrene sulfonamide) [140a]. 

---