The size requirements for PVC baseball used in adult competitions should comply with the standard specifications of baseball and be adjusted in combination with the characteristics of PVC material. The following is the specific analysis:
First, diameter and circumference
Diameter: The diameter of PVC baseball used in adult competitions is usually between 7.2 and 7.3 centimeters. This size is similar to that of a standard baseball, ensuring the stability and predictability of the baseball during flight and hitting.
Circumference: Calculated by diameter, the circumference of a PVC baseball used in adult competitions is approximately between 22.6 cm and 22.9 cm, which is also the commonly used size standard in baseball.
Second, weight
Weight range: The weight of PVC baseball used in adult competitions is usually between 140 and 160 grams, but the more common specification is close to the weight of a standard baseball, that is, 140 to 150 grams. This weight range not only ensures the stability of the baseball during flight but also enables the batter to swing the bat and hit it easily.
Third, materials and structure
The outer layer material: The outer layer of a PVC baseball is usually made of PVC material that is wear-resistant, water-resistant, and chemically resistant to ensure that the baseball can maintain good performance in various environments.
Core material: The core may be made of cork, rubber or similar substances to provide appropriate elasticity and resilience. The softness and impact resistance of PVC material can reduce the risk of collision injuries, making it suitable for adult competitions.
Sewing process: PVC baseballs usually adopt a high-density sewing thread reinforcement process, tightly wrapping the outer layer material around the inner core to form a complete sphere. This process can prevent the ball from cracking or the inner core from being exposed, and improve the durability of the baseball.
Fourth, other requirements
Surface treatment: The surface of PVC baseball may undergo special treatments, such as adding texture or coating, etc., to increase friction and grip strength, and enhance the user experience of the batter.
Certification standards: Although PVC baseballs may not fall into the traditional sense of “wooden bats” or “metal bats”, if they are used in official competitions, they still need to comply with the regulations of relevant event organizations or associations. For instance, some events may require bats to have specific performance factor (such as BPF) or batting elasticity coefficient (such as BBCOR) certifications.