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Technical rubber products

Technical rubber products

MagPro® 150 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 150 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 150 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.

In below table the various applications of MgO in rubber technology are listed:

RubberMgO Application
Rubber Uses
1Polychloroprene (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)

Butyl Rubber

acid scavengerTire inner tubes, tire air barriers, air cushions, pneumatic springs, accumulator bags, air bellows, tire expandable bladders, high temperature service hoses and conveyor belts
3Chlorobutyl Rubber (CIIR)retarder/scorch controlInnerliners 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
4Bromobutyl Rubber (BIIR)retarder/scorch controlTire innerliners, radial-tire black sidewalls, pharmaceutical closures, heat resistant conveyor belts, chemical resistant tank linings, curable contact cements to rubber-rubber adhesion

Nitrile Rubber

acid scavengerOil 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
6Chlorosulfonated 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
7FluoroElastomers (FKM)acid scavengerValve 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
8Polysulfide Elastomerscrosslinking agentPrinting and lacquer coating industries, hose tubes, gaskets, gas-meter diaphragms, sealants (aircraft, automobiles), coatings
9Epichlorohydrin Polymersacid scavengerFuel-air conditioning system components (hose, diaphragms, seals, gaskets, O-rings), vibration isolators, belts, rollers
10Chlorinated Polyethylene (CPE)acid scavengerHoses, cables, automotive tubing, boots, dust covers
11Phosphonitrilic Fluoroelastomers (PNF)increases modulus and adhesion to metalsAerospace, 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 MagProin neoprene is presented below:

Compound Recipe

Compound compositions
Neoprene GRT100100
Regal SRF-N772 (carbon black) 25 25
Stearic acid0.50.5
ODPA (Antioxidant)11
Zinc oxide RS55
Total phr lab135.5135.5

Sample nameMagPro 150Competetive synthetic magnesia
Mooney viscosity, ML (1+4) 100°C
Initial, (MU)75.374
Mooney viscosity, (MU)52.754.4
Original mechanical properties
Hardness, IRGD, 10 mm sample, (,SN)6262
Tensile strength at max, (MPa)24.724.5
Elongation at break, (%)582580
Hot-air ageing, 1 week at 100C
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

Contact us, our experts will provide you with advice on the use of the product

+7 495 789 65 30 sales@magminerals.ru