The role of magnesium oxide in rubber formulations

Although magnesium oxide is an important material in rubber, it plays a very important role.

Magnesium oxide can be used as vulcanizing agent, active agent, filler; it can increase the fixed tensile stress of vulcanized rubber prevent burning of rubber. It can increase the alkalinity of the compound, at the same time it has acid absorption effect, increases heat resistance thermal conductivity, is beneficial to the improvement of the vulcanization speed.

1. Magnesium oxide can be used as a reinforcing agent for heat-resistant rubber in nitrile rubber.

2. Used as vulcanizing agent active agent in neoprene, also has anti-scorching effect;

3. It is used as an acid absorbing agent in halogen-containing rubber.

4. as a thickener in the composite material.

5. Improve the rubber temperature resistance level, the effect is obvious.

6. it can increase the bonding performance with the metal skeleton improve the roll wrapping property of the compound rubber;

7. Can be used as vulcanizing agent in halogenated butyl rubber; sometimes as filler.

8. It also has the function of absorbing the free halogen decomposed by heat.

9. Magnesium oxide is often used in alloy adhesives, such as PVC CM, which can make the product part under-sulfur.

The role of zinc oxide in rubber formulations

Zinc oxide is the most important inorganic active agent in the rubber industry. Adding rubber compound can only accelerate the vulcanization speed, but also improve the degree of crosslinking. It can activate thiazoles, sulfenamides, guanidines thiuram accelerators. Widely used in various types of rubber products, especially for transparent rubber products products in contact with food. Zinc oxide is the active agent of natural latex.

Sometimes used as a reinforcing agent coloring agent.

50% of industrially produced zinc oxide flows to the rubber industry. As an important reactant of rubber vulcanization, zinc oxide stearic acid are one of the raw materials for rubber manufacturing. The combination of zinc oxide stearic acid enhances the degree of hardening of the rubber. Zinc oxide is also an important additive for automobile tires. In addition to vulcanization, zinc oxide can greatly improve the thermal conductivity of rubber, thereby contributing to the heat dissipation of tires ensuring driving safety. Zinc oxide additives also prevent the attack of rubber by mold organisms ultraviolet light.

⑴ The role of zinc oxide in the rubber tire industry (advanced black dark rubber tires, radial tires): improve the thermal conductivity, wear resistance, tear resistance, tensile strength other items of the product, save zinc oxide About 30%.

⑵ The role of zinc oxide in rubber products:

① Active zinc oxide is mainly used as a reinforcing agent for rubber, so that the rubber has good corrosion resistance, tear resistance, elasticity elongation.

②The accelerator used in the rubber vulcanization process is a multifunctional rubber compounding agent, which is mainly used as a vulcanization active agent reinforcing agent for natural rubber, synthetic rubber latex.

③When used as a vulcanization activator, it is evenly distributed in the rubber compound, with a large contact area with hydrogen sulfide, there is a greater opportunity for interfacial reaction. In addition, this active zinc oxide product has the catalytic effect of active substances to convert zinc oxide The conversion rate for zinc sulfide is high.

④As a vulcanizing oxidant, its role is to enhance the activity of the accelerator, reduce the amount of accelerator, shorten the vulcanization cycle.

⑤ It can accelerate the vulcanization speed, improve the thermal conductivity of vulcanizate, make vulcanization more thorough.

⑥ In the rubber industry, especially in the production of transparent rubber products, activated zinc oxide is an excellent vulcanization activator.

(3) The role of zinc oxide in synthetic rubber: act as an activator, vulcanization accelerator reinforcing agent, have a coloring effect. Promote the vulcanization, activation reinforcement of rubber, anti-aging, can strengthen the vulcanization process, improve the tear resistance wear resistance of rubber products.

⑷ The role of zinc oxide in natural rubber: as a vulcanization activator, to promote the vulcanization, activation reinforcement of rubber, anti-aging effect, can strengthen the vulcanization process, improve the tear resistance wear resistance of rubber products.

⑸ The role of zinc oxide in natural latex: act as an activator, promote the vulcanization, activation reinforcement of rubber, anti-aging effect, can strengthen the vulcanization process, improve the tear resistance wear resistance of rubber products.

⑹ The role of zinc oxide in white latex: as a coloring agent filler.

⑺The role of zinc oxide in neoprene: as a vulcanizing agent a compounding agent to increase thermal conductivity.

⑻The role of zinc oxide in the shoe industry (rubber shoes, rain boots, rubber gloves other labor protection products) (rubber shoes, rain boots, rubber gloves other labor protection products): improve wear resistance anti-aging, extend the service life.

⑼ The role of zinc oxide in transparent rubber rubber products for food: an essential inorganic active agent.

⑽ The role of zinc oxide in transparent translucent rubber: as vulcanization activator.

⑾The role of zinc oxide in transparent colored rubber products: It has the irreplaceable role of traditional active agents such as carbon black.

It is usually necessary to add zinc oxide to the sulfur/accelerator vulcanization system. The zinc oxide used has many different particle sizes, purity effectiveness. If the amount of zinc oxide is insufficient, only the physical mechanical properties (modulus, pressure change) are damaged, but also the resistance to vulcanization is poor. As the amount of zinc oxide increases, the anti-sulfuration reversion performance initially increases rapidly, but then increases very slowly. In the NR (conventional sulfur dosage + sulfenamide accelerator), after zinc oxide exceeds 4 to 5 parts, the resistance to sulfidation reversion is no longer increased.

The role of stearic acid in rubber formulations

Stearic acid is added as an adjunct. The proportion of addition is very small. Usually, 0.5-3 parts of stearic acid is added per 100 parts of rubber, but it is indispensable. As a vegetable oil-based fatty acid, after being added in a certain proportion during the processing of rubber (tires), it can be summarized to have the following four functions:

1. Softening plasticizing effects;

2. As an external lubricant;

3. Facilitate the full diffusion of carbon black, white carbon black zinc oxide;

4. Reacting with zinc oxide alkaline accelerator can promote its activity. It is also the main vulcanization accelerator can act as a second accelerator. Can accelerate hardening.

Since zinc oxide is insoluble in rubber, its active effect cannot be fully exerted when used alone, it must be used in combination with stearic acid to produce zinc soap (a complex of stearic acid zinc) that can be dissolved in rubber, then participate in the vulcanization reaction.

Stearic acid has an activation effect, which plays an acidic role in activating the double bonds of rubber molecules, thereby accelerating the formation of cross-linking bonds, can increase the cross-linking density of vulcanizates in certain vulcanization systems. In the alkaline accelerator their combined promotion system, it usually plays a role of delaying the onset of sulfur point. In addition, stearic acid can improve the dispersion effect of fillers, can also reduce the tendency of the rubber compound to stick to the roller. If the compound is filled with a large amount of reinforcing carbon black, the amount of stearic acid can be up to 3 parts to help dispersion. However, when the amount of stearic acid is high, the adhesion between rubber metal will be weakened.

It is worth noting that zinc stearate stearic acid produced during the vulcanization process of zinc stearate, the solubility in butadiene rubber is relatively small, so in the compound compound of butadiene rubber, excessive use of stearic acid will Causes frost spray.