Three EPDM (EPDM) has been widely used in automotive sealing and high-end doors and windows industry.
EPDM EPDM rubber high ozone resistance, heat resistance, weather resistance, low temperature flexible of is better. It can be used for ozone resistance, weather resistance, ultraviolet occasions, but based on its own characteristics, the flame retardancy, resistance to oil and low bond strength. This is the main chain structure of saturated rubber can be blended, can complement each other's performance. EPDM rubber backbone by the chemical stability of saturated hydrocarbon composition, only in the side chain containing unsaturated double bond, so basically belongs to the kind of saturation type rubber. Due to the molecular structure of non-polar substituents, the intermolecular energy in low, so molecular chain can maintain flexibility in a wide temperature range. The chemical structure of ethylene propylene rubber vulcanize products with unique properties.
A low density, high filling: three Yuan rubber is a kind of low density rubber, its density is 0. 87. Coupled with large filling oil and adding filler, so it can reduce the cost of rubber products, make up the shortcomings of EPDM rubber prices high, and the high Mooney value of EPDM rubber and filled high physical and mechanical properties decreased slightly.
Second, aging: ethylene propylene rubber has excellent weather resistance, ozone resistance, heat resistance, acid and alkali resistance, resistance to water vapor, color stability, electrical properties, filling oil and normal temperature liquidity. Three EPDM rubber products can be used for a long time under 120 degrees, at 150 to 200 DEG C under transient or intermittent use. Adding suitable antioxidant can improve the use of temperature. With three EPDM peroxide crosslinking can be used in harsh conditions. Three EPDM in ozone concentration of 50 * 10 ~ 30%, stretching, not cracked up to 150 hours or more.
Corrosion resistance: due to the lack of polarity of ethylene propylene rubber, low degree of unsaturation, and the very chemicals such as alcohol, acid, alkali, oxidant, refrigerants, cleaning agents, dynamic plant oil, ketone and ester has better resistance; but in fat and Fang is solvent (such as poor stability in mineral oil and gasoline, benzene and so on. In the long term effect of concentrated acid also decreased. In the ISO / TR7620 data in a collection of nearly 400 kinds of corrosive gas and liquid chemicals on various properties of rubber effect. Liu Yibing rubber role of 1 chemicals are more than 80 kinds, in which one one are not listed.
Four, water vapor: EPDM has excellent water vapor resistance and superior heat resistance. In the 230 degree of superheated steam, the appearance of the near 100h no change. And fluorine rubber, silicone rubber, fluorine silicone rubber, butyl rubber, nitrile rubber, natural rubber under the same conditions, shorter time appearance occurred obvious deterioration phenomenon.
Five, hot water resistance performance: three EPDM water resistant performance is good, but is closely related with the vulcanization system. Dithio bis morpholine, TMTD ethylene propylene rubber vulcanization system, 125 DEG C hot water soak 5 1 month after, mechanical properties change very little, volume expansion rate of only 0. 3%.
Sixth, the electricity performance: ternary ethylene propylene rubber has excellent electrical insulation properties and corona resistance, electric properties are better than or close to styrene butadiene rubber, chlorine sulfonated polyethylene, polyethylene and crosslinked polyethylene.
Seven, elastic: ternary ethylene propylene rubber molecular structure in non polar substituents, molecular cohesion is low, the molecular chain can be in a wide range of maintain flexibility, second only to natural rubber and butadiene rubber, and at low temperatures can still maintain.
Eight, bonding: ethylene propylene diene rubber due to a lack of active groups in the molecular structure and cohesive energy low, plastic material is easy to spray frost, adhesive and mutual viscosity is poor.
Automobile rubber sealing strip
First, an overview
The seal includes a window, door, ceiling, decorative, mosaic, flocking, coating and other varieties. Mainly used polyolefin, thermoplastic elastomer. Such as three Yuan rubber and rubber and thermoplastic elastomer TPE. The utility model has the advantages of good abrasion resistance, good weather resistance, small friction coefficient and simple manufacturing process. Some of the seal with a skeleton, a wide variety, such as steel, steel wire, aluminum tape. The strip also includes tensile steel, cutting strip, plate belt. And the tensile steel strip is divided into symmetrical tension steel strip and asymmetric tension steel strip. The punching strip is divided into single bridge and double bridge steel punching punching steel.
Two, automobile rubber sealing strip type, structure and main material
1, sealing strip type:
Seal a variety of species, commonly used are the following. For example: door seals, glass guide groove sealing strip, outside of the door sealing strip, radiator sealing, engine cover seal, luggage cover seal waterspout, seal, car decoration sealing strip.
2, sealing strip structure:
(1), pure rubber sealing strip (including foam sealing strip)
(2) and composite rubber seal (including foam sponge and dense glue);
(3) plastic and metal composite sealing strip;
(4), flocking or installation of surface treatment seal;
(5), rubber and sponge, foam metal multiple seal.
3, sealing strip main material:
(1) the general use of long branched three epdm;
(2) three, thermoplastic elastomer epdm;
(3), low friction material layer (heat in low friction plastic materials and thermal plastic of EPDM co extrusion of the compound in the sealing stripe surface).
Three, automotive sealing strip performance requirements
1, conventional properties such as hardness, tensile strength, elongation at break, compression permanent deformation, ozone aging resistance, resistance to ozone aging, resistant paint with infiltration performance.
2, finished product performance: including the door before the door closed