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Technical rubber products

 

Technical rubber products

MagPro® 140 is a high activity magnesium oxide with a precisely defined particle size distribution. It is produced by indirect calcination of fine milled magnesium hydroxide. This process safeguards a very high level of uniformity of both activity and particle size.
MagPro® 140 is added in rubbers to play the role of (a) acid scavenger, (b) scorch controller (vulcanization retarder), (c) vulcanization (or curing) agent, (d) vulcanization accelerator activator, (e) heat stabilizer. All these functions are exhibited during vulcanization and/or storage of intermediate or final products and in some cases during the service life of the article. MagPro® 140 has to be incorporated during a compounding or a pre-compounded additive process in order for the elastomer to be able to be crosslinked at a later stage.

# Rubber MgO Application Rubber Uses
1

Polychloroprene

(CR) 

crosslinking agent, retarder/scorch control,               acid scavenger,

heat stabilizer

 

Adhesives, automotive (V-belts, timing belts, gaskets for door, deck and trunk), wire&cable, petroleum exploration, production and distribution (pipeline pigs, seals, gaskets, hoses), construction (gaskets, roof covering, modified asphalt), shoes, foam mattresses (latex)
2

Butyl Rubber

(IIR) 

acid scavenger  Tire inner tubes, tire air barriers, air cushions, pneumatic springs, accumulator bags, air bellows, tire expandable bladders, high temperature service hoses and conveyor belts 
3 Chlorobutyl Rubber (CIIR)  retarder/scorch control  Innerliners for tubeless tires, tire sidewalls, heat-resistant truck inner tubes, hoses, gaskets, conveyor belts, adhesives and sealants, tire curing bags, tank linings, truckcab mounts, aircraft engine mounts, rail pads, bridge bearing pads, pharmaceutical stoppers, appliance parts 
4 Bromobutyl Rubber (BIIR)  retarder/scorch control  Tire innerliners, radial-tire black sidewalls, pharmaceutical closures, heat resistant conveyor belts, chemical resistant tank linings, curable contact cements to rubber-rubber adhesion 
5

Nitrile Rubber

(NBR) 

acid scavenger  Oil and chemical resistant hoses (automotive, marine, aircraft fuel lines, bulk-fule transfer, chemical transfer, food handling, dairy and creamery), oil-drilling items, cements, adhesives, gaskets, brake linings 
6 Chlorosulfonated Polyethylene (CSM)

  accelerator activator,

  acid scavenger,

 heat stabilizer 

Coating rubber films (roofs, tarpaulins, pond liners), caulks and adhesives, wire&cable, air-conditioner hoses, spark-plug boots, rollers, automotive gaskets 
7 FluoroElastomers (FKM)  acid scavenger  Valve seals, O-rings, gaskets, joints, hose, wire & cable, automotive seals, fuel handling systems, aerospace, oil-well seals and packers, oil-suction delivery hoses, tank linings, seals for scientific instruments 
8 Polysulfide Elastomers  crosslinking agent Printing and lacquer coating industries, hose tubes, gaskets, gas-meter diaphragms, sealants (aircraft, automobiles), coatings 
9 Epichlorohydrin Polymers  acid scavenger  Fuel-air conditioning system components (hose, diaphragms, seals, gaskets, O-rings), vibration isolators, belts, rollers 
10 Chlorinated Polyethylene (CPE) acid scavenger  Hoses, cables, automotive tubing, boots, dust covers 
11 Phosphonitrilic Fluoroelastomers (PNF)  increases modulus and adhesion to metals  Aerospace, military, petrochemical and other critical applications 

Magnesium oxide is most widely used in Polychloroprene (CR), a synthetic rubber invented by DuPont and commercially announced under the trade name of Neoprene® in 1931. Some known applications include automotive components, wire&cable, hoses, seals, gaskets, roofing and adhesives. CR grades are characterized by toughness, wide operating temperature range, resistance to oils, heat, ozone and weathering, as well as inherent flame retardant properties due to chlorine content.

The various grades of Neoprene fall within three general types, G, W and T. Within each type there is a series of grades with specific properties for a variety of processing conditions, compounding considerations, vulcanization systems and product applications.

Use of 4 parts MgO and 5 parts ZnO generally results in a good balance of processing safety and cure rate and is typically applied. Higher levels of magnesia may be desirable for high temperature molding, especially injection molding. Lower levels of MgO (2 pphr) may be used in some continuous vulcanization cure systems.

The basic compound composition of using MagPro® in neoprene is presented below:

Compound Recipe
Compound composition
Neoprene GRT 100 100
Regal SRF-N772 (carbon black) 25 25
Stearic acid 0.5 0.5
MgO 4 4
ODPA (Antioxidant) 1 1
Zinc oxide RS 5 5
Total phr lab 135.5 135.5

 

  Properties
Sample name MagPro 140® Competetive synthetic magnesia 

Mooney viscosity, ML (1+4) 100° C

Initial, (MU) 75.3 74
Mooney viscosity, (MU) 52.7 54.4
Original mechanical properties
Hardness, IRGD, 10 mm sample, (°,SN) 62 62
Tensile strength at max, (MPa) 24.7 24.5
Elongation at break, (%) 582 580
Hot-air ageing, 1 week at 100° C
Variation in tensile strength, (%) -11 -14
Variation in elongation, (%) -29 -38

The primary function of MgO in Neoprene compounds is to neutralize trace hydrogen chloride liberated by the polymer during processing vulcanization (also termed crosslinking or curing), heat aging or service. By neutralizing the hydrogen chloride, magnesium oxide prevents auto- catalytic decomposition, resulting in greater stability. MgO also takes part in the vulcanization process regulating scorch

Advantages of MagPro®

 ·         combines the best characteristics of both synthetic and natural magnesia
·         does not contain any volatiles like chlorides and sulphates
·         has a high and uniform reactivity for perfect reproducibility
·         has a precisely defined particle size distribution
·         has short delivery times: produced in Europe and distributed through a dense sales network

 

 

 

Specifications

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