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.

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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.

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

#	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 compositions
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

MagPro®

+7 495 789 65 30 sales@magminerals.ru

Specifications

MagPro® 140
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