The phenyl-vinyl vulcanization system is an important rubber vulcanization technology with unique performance advantages in the manufacture of molded O-rings. The performance stability of this vulcanization system in molded O-rings is analyzed from several aspects:

Basic Characteristics of the Phenyl-Vinyl Vulcanization System
The main chemical component of the phenyl-vinyl vulcanization system is phenyl vinyl sulfide (C8H8S), a colorless to pale yellow liquid with the following physicochemical properties:

Density: 1.042 g/mL (25°C)
Boiling Point: 94-95°C (25 mmHg)
Flash Point: 114°F
Refractive Index: n20/D 1.599
Storage Conditions: 2-8°C, usually with the addition of tert-butylcatechol (TBC) as a stabilizer.

Through the dual action of phenyl and vinyl groups, this vulcanization system can provide an excellent cross-linked network structure, thereby enhancing the mechanical properties and aging resistance of rubber products.

Manufacturing Process and Material Requirements for Molded O-rings
Molded O-rings are mainly manufactured using two processes:
Compression Molding: The raw material is manually added to the mold before the upper and lower molds are combined. Suitable for small-batch and large-size manufacturing.

Injection Molding: The raw material is automatically injected into a multi-cavity mold. Suitable for large-batch and small-size manufacturing.

Commonly used materials include:
Nitrile Rubber (NBR): Good oil resistance, low cost, operating temperature -40~120°C
Fluororubber (FKM): Resistant to high temperatures and chemical corrosion, operating temperature -20~250°C
Silicone Rubber (VMQ): Resistant to high and low temperatures, operating temperature -55~250°C
Material selection must comprehensively consider the medium, temperature, and pressure requirements, and comply with industry standards such as GB 1235-76 and AS568.

Performance of Phenyl-Vinyl Vulcanization System in O-rings
The phenyl-vinyl vulcanization system exhibits the following performance advantages in O-rings:
* **Heat Resistance:** The phenyl structure provides excellent high-temperature resistance, while the vinyl structure enhances crosslinking density.
* **Chemical Resistance:** It has good resistance to various oils and chemical media.
* **Mechanical Properties:** The vulcanized rubber has high tensile strength and elastic modulus.
* **Compression Set:** Superior to traditional sulfur vulcanization systems, resulting in more stable long-term sealing performance. This vulcanization system is particularly suitable for applications requiring long-term stable sealing, such as:
* **Hydraulic System Seals**
* **Pneumatic System Seals**
* **Automotive Engine Seals**
* **Petrochemical Equipment Seals**
Performance Testing and Industry Standards

Performance testing of phenyl-vinyl vulcanized O-rings mainly includes:
**Test Items | Test Methods | Standard Requirements**
* **Appearance Inspection |** Visual inspection. No scratches, cracks, bubbles, or other defects.
* **Dimensional Measurement |** Micrometer/diameter gauge. Inner diameter deviation ±0.13mm (≤50mm).
* **Hardness Testing |** Shore hardness tester. Range determined according to material type.
* **Compression Set |** Compression test. Deformation rate at high temperature ≤30%
Chemical resistance: Immersion test, mass change rate ≤15%

Industry standard specifications:
Vulcanization temperature: 165-175°C
Vulcanization time: Determined based on rubber rheometer t90 time and product thickness
Material properties: Complies with HG/T 2579-2008 standard

Comparison with other vulcanization systems
The phenyl-vinyl vulcanization system has the following advantages compared to traditional vulcanization systems:
Vulcanization System | Advantages | Disadvantages
Phenyl-vinyl | Good heat resistance, low compression set, excellent long-term stability | Higher cost, strict process control requirements
Sulfur vulcanization | Low cost, mature process | Poor heat resistance, large compression set
Peroxide | Good aging resistance Not suitable for certain rubbers; strong odor.
Application Recommendations
Material Selection: For high-temperature, high-pressure, or chemically corrosive environments, prioritize fluororubber or silicone rubber O-rings with a phenyl-vinyl vulcanization system.
Process Control: Strictly adhere to the recommended vulcanization temperature and time to ensure sufficient crosslinking.
Storage Conditions: Unvulcanized phenyl-vinyl vulcanizates should be stored at 2-8°C.

Performance Verification: Comprehensive performance testing, including compression set and media resistance tests, should be conducted before mass production.