Automotive fluid resistance

These grades have been developed to give improved chemical resistance to automotive fluids such as gear lubricants, transmission and power steering fluids, engine oils, and rust inhibited engine coolants. Resistance to aromatic hydrocarbons is reduced. 

High heat resistance and oil resistance. Superior resistance to automotive fluids than other fluorocarbon types. Self extinguishing. Relatively poor cold performance. High cost. Lower resistance to aromatic hydrocarbons than other fluorocarbon types. 

Because of their resistance to automotive fluids CM are used for hoses, tubing, air ducts and wire jacketing, tubes and covers for return side power steering hoses, single construction emission and vacuum tubing, hose covers, large diameters and convoluted geometries required for air intake ducts... 

PBT/elastomer blends display a unique combination of high impact strength, dimensional stability due to their non-hygroscopic namre, excellent resistance to automotive fluids such as gasoline, oils, paint solvent, aqueous salt solutions and good heat resistance. In addition, their easy processability (low melt viscosities) lends... 

Chem. Descrip. Alkyltrialkoxy silane with oleophobic additive Uses Water repellent tor concrete, brick, and nat. stone Features Resist, to automotive fluids, water intnision, chloride ion screening low VOC... 

In the engine compartment, the k properties tend to be resistance to automotive fluids, and mechanical properties over a wide range of operating temperatures. For example, glass-fibre filled nylons are chosen for... 

Having been first commercialized in 1972, EPDM/PP TPOs are used mainly in external antomotive and electrical applications np to 80°C. Automotive uses include exterior trim such as bumpers, fascia, and nonsealing moldings however, under-the-hood nses are generally exclnded because of temperature and fluid-resistance requirements in the engine compartment. 

Higher heat resistance, i.e., higher property retention in hot air Spike temperature resistance to 175 °C long-term use heat resistance to 150 °C Higher chemical resistance (to hot, aggressive automotive fluids)... 

Hence, from above properties, the PA/acrylate mbber TPV is particularly suited to various automotive under-the-hood applications where high heat and fluid resistance is needed such as in automotive boots (CVJ, rack, and pinion), noise/ vibration dampening components, dynamic seals, dust covers, underbody/e-coat plugs, grommets, clean air-intake ducts, transmission oil cooler hose, and so on. The nonautomotive applications take advantage of its better overmolding adhesion to nylons to make soft-touch, nylon parts such as power tool handles, overmolded clips, fasteners, and connectors. 

Commercially, polyamide (PA6)-based thermoplastic silicone vulcanizates are commercialized by Multibase, a Dow Coming company tmder the trade name Tpsiv 1180-50D. It was evaluated for automotive brake hose application because of its hot brake fluid resistance (to 150 °C). The high cost of silicones may limit the use of such nylon blends only to specialty niche applications. 

The unique difference between PPE/PA blends and PPE/HIPS blends is illustrated by (a) the differences in DTUL at 0.45 MPa and the DTUL at 1.82 MPa in glass-reinforced compositions (b) the difference in their relative sensitivity or resistance to chemicals, e.g., some common solvents and automotive fluids (Table 19.26). These differences arise from the facts that (a) polyamide is a crystalline polymer unlike HIPS, which is amorphous and (b) due to the large melt viscosity difference between polyamide and PPE at the normal blend ratios, the polyamide forms the continuous phase. Hence, in the molded parts, the polyamide surface offers resistance to solvent permeation and high softening temperature. In PPE/HIPS blends due to the singlephase amorphous character of the matrix, the solvent resistance is limited, and the heat resistance is limited by the Tg of the blend. Because of these differences, PPE/PA blends have found significant application niches. 

Dyneon BREs (base-resistant elastomers) are used in applications exposed to automotive fluids such as ATF, gear lubricants, engine oils shaft seals, 0-rings, and gaskets. 

Acrylic rubber can be emulsion- and suspension-polymerized from acrylic esters such as ethyl, butyl, and/or methoxyethyl acetate to produce polymers of ethyl acetate and copolymers of ethyl, butyl, and methoxyl acetate. Polyacrylate rubber, such as Acron from Cancarb Ltd., Alberta, Canada, possesses heat resistance and oil resistance between nitrile and silicone rubbers. Acrylic rubbers retain properties in the presence of hot oils and other automotive fluids, and resist softening or cracking when exposed to air up to 392°F (200°C). The copolymers retain flexibility down to -40°F (-40°C). Automotive seals and gaskets comprise a major market. These properties and inherent ozone resistance are largely due to the polymer s saturated backbone (see Table 3.13). 

PPS, 40% glass fibre reinforced Automotive head lamps, petrol, oil and hydraulic fluid resistant parts, exhaust gas emissions, control valves, pumps, precision mechanical parts Terminal blocks, connectors, electric motor housings, boxes for electronic components High heat applications High chemical resistance applications... 

Applications include the automotive, wire and cable markets, as well as general mechanical applications. Other automotive uses include exterior trim such as bumpers, fascia, and nonsealing molding, whereas under-the-hood uses are limited because of temperature- and fluid resistance requirements. TPOs are also used in sporting goods because of flexibility, feel, and good colorability. 

TABLE 15.7 Resistance of Poly(Phenylene Sulfide)-Based Compounds to Automotive Fluids... 

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