Polyolefins polyethylene automotive

Harden s (27) market survey of the growth of polyolefin foams production and sales shows that 114 x 10 kg of PE was used to make PE foam in 2001. The growth rate for the next 6 years was predicted as 5-6% per year, due to recovery in the US economy and to penetration of the automotive sector. In North America, 50% of the demand was for uncrosslinked foam, 24% for crosslinked PE foams, 15% for EPP, 6% for PP foams, 3% for EVA foams and 2% for polyethylene bead (EPE) foam. As protective packaging is the largest PE foam use sector, PE foam competes with a number of other packaging materials. Substitution of bead foam products (EPP, EPE, ARCEL copolymer) by extruded non-crosslinked PE foams, produced by the metallocene process was expected on the grounds of reduced costs. Compared with EPS foams the polyolefin foams have a lower yield stress for a given density. Compared with PU foams, the upper use temperature of polyolefin foams tends to be lower. Eor both these reasons, these foams are likely to coexist. 

The production of polyolefins such as polyethylene (PE) or polypropylene (PP) and their copolymers increases continuously due to their outstanding product properties and their environmental compatibility. They are commonly applied as packing material. foils, fibers, as well as components for the automotive and electrical industry. In 1996 the worldwide production of PE and PP counted 40 million and 20 million tons, respectively. On the basis of the global demand. the growth rate of PP production is predicted to rise up to 7% per year until 2002/ 2003. 

Polyolefins are used in automotive industry due to their low cost, good weather resistance, and excellent properties. They can be used in many parts to reduce the vehicle weight, save fuel, increase comfort, and reduce CO2 emission. Polyethylene (UHMWPE or HDPE), for example, is used to absorb vibration and noise and for impact protection. Polypropylene is one of the lightest polyolefins, and with a proper design, an improvement in the passenger safety can be achieved. Polypropylene can also be used in bumper systems to absorb the kinetic energy. 

The technique commonly used to separate household packaging wastes is sensor-based near-infrared spectroscopy that is based on the fact that NIR spectra of different types of polymers are quite distinct. NIR is able to provide rapid and reliable identification of various polymers especially the polyolefin group, polyethylene (PE), and polypropylene (PP). However, the objects which are too small or too big are not suitable for this technology. Another drawback is its inability to detect dark polymers, like automotive parts and some of the electronics waste, since radiation is absorbed completely. In practice, for packaging polymers, around half of the total input materials end up in residuals. 

Zotefoams has added new F grades to its ED-15 polyethylene foam range to meet the needs of the automotive and aerospace markets. The range of foams is the lightest available for crosslinked foam with a density of 15 kg/m, some 30% lighter than any other polyolefin foam, and is made in LDPE and metallocene catalysed polyolefins. 

The recent proliferation of metallocene-based polyolefins and polyolefin elastomers have gained their popularity owing to their density, cost, and ease of processabUity. PVC/POE blends have therefore been investigated as flexible PVC compounds. However, these blends are thermodynamically immiscible and needed suitable compatibiUzers such as the chlorinated polyethylenes (Eastman and Dadmun 2002). Since they are not miscible, POEs do not lower the PVC modulus sufficiently unless some plasticizer or a compatible elastomer such as EPE is also added. Commercially, some PVC/POE alloys are offered by TeknorApex under Flexalloy trade name with a shore A hardness 40-60 and brittle points down to —50 °C. They are claimed to have excellent low-temperature toughness, flexibility, compression set-resistance, and oil resistance. Suitable applications include automotive hoses, seals, gaskets, wire jacketing, etc. 

Polyolefin blends are of critical importance to the success of the material. Ethylene propylene diene rubber (EPDM) immiscibly blends with PP as an impact modifier. It is the most common and most commercially utilised blend of polyolefins. High-density polyethylene (HOPE) can be added to this blend to achieve maximum toughness [11-13]. Applications include wire and cable insulation, automotive... 

In polyolefins, it is used mainly in LDPE wire and cable insulation. Other uses reported or claimed include EVA wire and cable and foam carpet-backing EMA wire and cable EPR and EPDM wire and cable, electrical insulation, roofing, and automotive parts— white-wall tires, hoses, seals, and weather stripping XLPE wire and cable chlorosulfonated polyethylene and HDPE and polybutene. There is considerable interest in its use in PP cabinets (less smoke than polystyrene). 

Chlorinated polyolefins are used as adhesion promoters for coatings and inks on polyolefin plastics. They can be used as primers on polyethylene, polypropylene, and thermoplastic polyolefins (polypro-pylene/elastomer blends). They are used for adhesion of paint to plastic surfaces in the automotive industry. 

Lord Corporation introduced adhesives containing methacrylated phosphate monomers that gave much-improved thermal and atmospheric durability, and Dymax Corporation introduced their aerobic acrylics that were less sensitive to inhibition by atmospheric oxygen. Dow Automotive, 3M, and Loctite recently introduced two-part acrylic-based adhesives that can bond many low-surface-energy plastics, including many grades of polypropylene, polyethylene, and thermoplastic polyolefins without special surface preparation (see Section 4.2.2 for a description of this technology). 

SBS and SEBS block copolymers have been employed to impact modify HIPS, PPO/HIPS and various polyolefins. Maleic anhydride modified SEBS offers impact modification of polyamides and polyesters via reactive compatibilization. Chlorinated polyethylene (< 42 wt% Cl) is employed as an impact modifier for PVC, where weatherability is a primary concern [121]. Ethylene-(meth)acrylic acid copolymers and their neutralized versions (ionomers) have been utilized as impact modifiers for polyamides. PBT and PET impact modification with the poly(ester-ether block copolymer) (PBT-poly(tetramethylene oxide) (AB) ) yielded utility in automotive fascia applications. These products have been available under the tradenames Lomod (GE), Bexloy (duPont) andRiteflex (Hoechst-Celanese) [3]. 

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