The relationship between rubber process formulations and various physical properties

Rubber, as a kind of polymer material with elasticity, insulation, impermeability to water and air, is widely used in all aspects of industry and life. The performance of rubber products largely depends on their process formulas. This article will explore the relationship between rubber process formulations and physical properties such as tensile strength, tear strength, hardness, and wear resistance.

I. Basic Components of Rubber Process Formulas

Rubber formulations contain a variety of components, also known as compounding agents, and each component plays a different role in the rubber compound. The main components include:

Raw rubber: As the main material of the formula, it can be a single type of rubber or a combination of multiple types, such as natural rubber (NR), styrene-butadiene rubber (SBR), nitrile rubber (NBR), etc. The type and content of raw rubber determine the most fundamental characteristics of the rubber compound.

2. Vulcanization system: It includes vulcanizing agents, accelerators and active agents. Vulcanizing agents such as sulfur and peroxides cause cross-linking between rubber macromolecules, forming a three-dimensional network structure, which enhances the physical and mechanical properties of rubber, including strength and elasticity. Accelerators accelerate the vulcanization rate and shorten the vulcanization time. Active agents increase the activity of accelerators.

3. Reinforcing and filling system: Reinforcing agents such as carbon black and silica enhance the mechanical properties of the rubber compound, including tensile strength, tensile stress at a given elongation, and hardness. Fillers such as clay and calcium carbonate mainly serve to fill and reduce costs.

4. Protective system: Prevents rubber products from degrading or aging due to the effects of light, heat and oxygen during storage and use.

5. Processing AIDS: Enhance the processability of the rubber compound and reduce energy consumption, including operating oil, plasticizers, homogenizers, etc.

6. Bonding system: Enhance the bonding between rubber and reinforcing materials such as steel cord and fibers.

7. Other components: such as colorants, coupling agents, antistatic agents, foaming agents, etc.

Ii. The Relationship between Rubber Process Formulas and Physical Properties

Tensile strength

Tensile strength is the ultimate ability of rubber products to resist tensile failure and is one of the important indicators of rubber products. The tensile strength of rubber is closely related to factors such as its structure, molecular weight and crosslinking density. The selection and dosage of the vulcanization system directly affect the tensile strength. For instance, vulcanization with sulfur and regulating the vulcanization rate through accelerators can enhance the tensile strength. Reinforcing agents such as carbon black also have a significant impact on tensile strength. The smaller the material diameter and the larger the specific surface area, the better the reinforcing performance.

2. Tear strength

Tear strength refers to the resistance of rubber products when subjected to tear force. Tear strength is closely related to the crosslinking density of rubber, vulcanization system, reinforcing and filling system, etc. Polysulfur bonds and an appropriate amount of sulfur are beneficial for enhancing tear strength. Reinforcing agents such as carbon black and silica can also significantly enhance tear strength.

3. Hardness and tensile stress at a given elongation

Hardness and tensile stress at a given elongation are important indicators of the stiffness of rubber materials. With the increase of crosslinking density, both hardness and tensile stress at a given elongation will increase. Reinforcing agents such as carbon black can not only enhance tensile strength, but also significantly increase hardness and tensile stress at a given elongation. In addition, the adjustment of vulcanizing agents, accelerators and active agents also has a significant impact on hardness and tensile stress at a given elongation.

4. Wear resistance

Wear resistance refers to the ability of vulcanized rubber to resist surface damage under the action of friction, which is closely related to the service life of rubber products. Wear resistance is related to factors such as the type of rubber, vulcanization system, the amount and dispersibility of reinforcing agents, and the type of softener. Generally speaking, NBR (Nitrile butadiene rubber) has better wear resistance, and a reasonable vulcanization system and the amount of reinforcing agent can also significantly improve its wear resistance.

5. Elasticity

The high elasticity of rubber stems from the mobility of its molecular chain segments. The smaller the intermolecular forces of rubber are, the easier the movement of molecular chain segments will be, and the better the elasticity will be. Natural rubber and butadiene rubber have the best elastic performance due to their high regularity of molecular chain segments. The vulcanization system also has a certain influence on elasticity. A reasonable crosslinking density can ensure that the rubber quickly returns to its original state after being subjected to force.

Iii. Conclusion

The relationship between rubber process formulations and various physical properties is complex and close. By adjusting the proportion and types of raw rubber types, vulcanization systems, reinforcing and filling systems, protective systems, processing AIDS and other components in the formula, the physical properties such as tensile strength, tear strength, hardness, wear resistance and elasticity of rubber products can be significantly affected. Therefore, in the design and production process of rubber products, scientific and reasonable formula design is of vital importance.

Through continuous research and experiments, people have mastered the inherent laws of rubber formula design and developed a variety of rubber products with superior performance, bringing great convenience to industry and life. In the future, with the advancement of technology and the deepening of research, the relationship between rubber process formulas and physical properties will be more deeply revealed and applied.

FOREVER SEALS! Seals manufacturer, accept custom seals, from design to research and development, from production to testing, a full range of services. For more information, please contact FOREVER SEALS directly. FOREVER SEALS product experts are here to help you! Whatsapp: +86-18098184099；WeChat: +86-13049188460；  E-mail: sales@foreverseals.com.