HIGH ELASTICITY AND RESTORABILITY BALL STRUCTURE

Description

TECHNICAL FIELD

The invention relates to the field of sporting goods, in particular to a high elasticity and restorability ball structure.

BACKGROUND ART

In the prior art, there are a wide variety of structures and materials for the sports competition and training balls. Universally speaking, these balls are mainly made of polyvinyl chloride (PVC) or rubber or rubber and plastic copolymer materials. Although these materials have a certain elasticity, but expose a lot of deficiencies during use.

For example, in the case of the existing inflatable balls, the cavity wrapping layer of the ball is composed of multiple pieces of vulcanized rubber, gas leakage is easily caused in the ball cavity due to rubber aging, or the vulcanized rubber itself is still aged in the environment, resulting in the shape change of the ball cavity wrapping layer and the failure to maintain a good fixed cavity and the roundness consistency.

Secondly, the service life of these balls is relatively short due to the limitations of the material performance and the preparation process. In the actual use, the balls are prone to deformation as well as elasticity decline and weakening due to the lack of material protection and aging resistance, thereby reducing the service life and increasing the use and maintenance costs.

In addition, the manufacturing process of the traditional balls usually includes multiple complex steps, such as material preparation, molding, inflation, sealing and testing. Each step requires precise control, and the processes are linked closely. Once a process goes wrong, the manufacturing process may be restarted, resulting in low production efficiency.

For example, the inflation process and the subsequent deflation test are integral to the ball manufacture, but relatively time-consuming. Inflation is to ensure that the pressure inside the ball is up to standard, and the deflation test is to verify the sealing performance of the ball, thereby increasing the overall manufacturing time. In addition, more workers are required in the traditional ball manufacturing to ensure the smooth operation of the production line due to the tedious preparation process and long production time. Each of the traditional ball manufacturing processes consumes energy, such as material heating, operation of molding equipment and energy consumption of inflating equipment. Long-time and large-scale production results in a lot of energy consumption, which is not conducive to energy conservation and environmental protection.

In addition, the competition and training balls in the prior art are generally not wrapped with other materials outside. Although this design simplifies the ball structure, it affects the ball performance to a certain extent. For example, the ball without the protection of outer layer is more susceptible to damage from the external environment, such as ultraviolet light and moisture, thereby accelerating the aging process of the ball.

SUMMARY OF THE INVENTION

To solve the above problems, the invention provides a high elasticity and restorability ball structure. A foamed ball core and ball surface patches are prepared by using a supercritical foaming process, the special properties of which give the ball excellent elasticity and restorability. Compared with the traditional inflatable balls, the ball in the proposal can restore to the original shape more quickly after undergoing the impact of external forces, significantly boosting the use experience and ensuring the roundness consistency of the ball structure.

To achieve the above purpose, the invention adopts the following technical proposal: a high elasticity and restorability ball structure comprises a foamed ball core, wherein a reinforcing layer is arranged outside the foamed ball core, and a plurality of ball surface patches are bonded to the periphery of the reinforcing layer; the foamed ball core and/or the ball surface patches are prepared by using a supercritical foaming process.

As a further optimized proposal, the foamed ball core is at least one of polyurethane foamed ball core, EVA foamed ball core, TPE foamed ball core, SBR foamed ball core, NBR foamed ball core, EPDM foamed ball core, SBL foamed ball core, POE foamed ball core, PE foamed ball core, TPR foamed ball core, TPU foamed ball core and TPEE foamed ball core.

As a further optimized proposal, the diameter of the foamed ball core is 8 cm to 25 cm.

As a further optimized proposal, the reinforcing layer is a non-woven or woven fabric, which is bonded to the periphery of the foamed ball core by hot pressing or gluing.

As a further optimized proposal, the reinforcing layer is a winding layer, which is bonded with the periphery of the foamed ball core through adhesive or latex.

As a further optimized proposal, the winding layer is made of at least one of polyester-cotton yarn, cotton yarn, polyester yarn and nylon yarn by winding.

As a further optimized proposal, the ball surface patch comprises a foamed ball surface layer and a film layer bonded successively, wherein the foamed ball surface layer is bonded to the surface of the reinforcing layer, the thickness of the foamed ball surface layer is 1 mm to 20 mm, and the thickness of the film layer is 0.1 mm to 5 mm.

As a further optimized proposal, the foamed ball surface layer is made of at least one of polyurethane, EVA, TPE, SBR, NBR, EPDM, SBL, POE, PE, TPR, TPU and TPEE and is prepared by using a supercritical foaming process.

As a further optimized proposal, an inner or outer layer of the film layer is provided with a printing layer by means of painting or printing or thermal transfer printing or water transfer printing or cold transfer printing or pad printing.

As a further optimized proposal, a groove is arranged on the surface of the foamed ball surface layer.

The invention has the following beneficial effects:

• • 1. The foamed ball core and the ball surface patches are prepared by using a supercritical foaming process, which has a special property that small irregular foam structures are formed in the foaming process, thus giving the ball excellent elasticity and restorability. Compared with the traditional inflatable balls, the proposal is based on the foamed ball core and the ball surface patches prepared by using the supercritical foaming process, and therefore the ball can still maintain excellent elasticity, restorability and roundness consistency even after a long period of use.
  • 2. In the proposal, the reinforcing layer is arranged outside the foamed ball core, which not only enhances the overall stability of the ball, but also makes the ball better disperse and resist the impact of external forces, and ensures the roundness consistency of the ball during use, thus effectively extending the service life of the ball. Meanwhile, the reinforcing layer also reduces the performance decline caused by impact, and further enhances the roundness consistency of the ball.
  • 3. A plurality of ball surface patches are bonded to the periphery of the reinforcing layer, wherein the ball surface patch comprises a foamed ball surface layer and a film layer. The film layer is made of a variety of high-performance materials, such as polyurethane, TPU, PVC, etc., with good flexibility, protection, chemical corrosion resistance and wear resistance. This design not only protects the foamed ball surface layer from the damage of the external environment, but also offers the ball better waterproof, dustproof and anti-fouling properties, making the ball still maintain stable performance in the harsh environment, while ensuring that the ball can keep clean and improving the appearance after a long time of use.
  • 4. In the proposal of the application, the foamed ball core and the ball surface patches are prepared by using the supercritical foaming process, which greatly simplifies the process compared with the traditional manufacturing process of inflatable balls. The supercritical foaming process can complete the foaming and molding of the materials in a relatively short time, and has no need for complex inflating and deflating tests, thereby significantly improving the production efficiency, and reducing energy consumption and waste. Moreover, fewer staff is required due to the simplified manufacturing process and shortened manufacturing cycle time, and the supercritical foaming process with a higher degree of automation can reduce the dependence on manual operation, thereby reducing labor costs, and improving the stability and reliability of the production line.
  • 5. The ball prepared in the proposal of the application has fixation properties (quantitative data), which means that the size, shape, performance and other parameters of the ball can be accurately controlled, being more in line with the requirements of the automated process, and promoting a smoother and more efficient manufacturing process.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is the schematic diagram for a profile structure of a ball structure.

FIG. 2 is the schematic diagram of an embodiment using one ball surface patch.

FIG. 3 is the schematic diagram of an embodiment using another ball surface patch.

FIG. 4 the schematic diagram for a ball structure as a rugby structure.

FIG. 5 is the structural diagram for a high-precision rebound resilience tester.

FIG. 6 is the schematic diagram for a roundness measuring instrument.

Reference signs: 1. Foamed ball core; 2. Reinforcing layer; 3. Ball surface patch; 3A. Foamed ball surface layer; 3B. Film layer.

DETAILED DESCRIPTION OF THE INVENTION

As shown in FIG. 1, the invention relates to a high elasticity and restorability ball structure, comprising a foamed ball core 1, wherein a reinforcing layer 2 is arranged outside the foamed ball core 1, and a plurality of ball surface patches 3 are bonded to the periphery of the reinforcing layer 2; the foamed ball core 1 and/or the ball surface patches 3 are prepared by using a supercritical foaming process.

As the internal core component of the ball structure, the foamed ball core 1 is prepared by using a supercritical foaming process. This process makes numerous irregular small multi-foam porosity structures formed inside the material in the foaming process under precise temperature control and pressure conditions. These foam structures give the ball excellent elastic properties, so that the ball core can be quickly restored to the original form after being impacted by external forces, providing excellent experience and effect. It is worth noting that the foamed ball core 1 is not actually limited to the traditional ball structure although its name contains the words “ball core”. According to the specific design requirements and application scenarios, the foamed ball core 1 can be designed into a variety of irregular shapes to adapt to different ball sports and performance requirements. This flexibility allows the ball core to better match the external structure, ensuring the overall stability and consistency of the ball.

Moreover, in the embodiment, the foamed ball core 1 is EVA foamed ball core 1, TPE foamed ball core 1, SBR foamed ball core 1, NBR foamed ball core 1, EPDM foamed ball core 1, SBL foamed ball core 1, POE foamed ball core 1, PE foamed ball core 1, or TPR foamed ball core 1, TPU foamed ball core 1, TPEE foamed ball core 1, or polyurethane foamed ball core 1.

The characteristics of different materials are described below:

• • TPU (thermoplastic polyurethane) is characterized by wear resistance, oil resistance, low temperature resistance, excellent rebound resilience and high durability;
  • TPEE (thermoplastic polyester elastomer) can be regarded as an upgraded TPU, which is similar to TPU in rebound, durability and other indexes, but significantly improved in light weight. It is suitable for the production of sports balls with high requirements for light weight;
  • EVA (ethylene-vinyl acetate) has characteristics that foamed EVA material has good elasticity and flexibility despite of an average level of durability. Traditional foamed materials of shoes are also suitable for the production of sports balls with cost requirements.

In the embodiment, polyurethane, TPU and TPEE are preferred in the supercritical foaming process.

Further, the reinforcing layer 2 is a non-woven or woven fabric, which is bonded to the periphery of the foamed ball core 1 by hot pressing or gluing. The woven fabric is made of 20-count or 30-count or 40-count yarns.

In the embodiment, the reinforcing layer 2 is arranged outside the foamed ball core 1, which not only enhances the overall stability of the ball, but also makes the ball better disperse and resist the impact of external forces, and ensures the roundness consistency of the ball during use, thus effectively extending the service life of the ball. Meanwhile, the reinforcing layer 2 also reduces the performance decline caused by impact, and further enhances the roundness consistency of the ball.

As another embodiment, the reinforcing layer 2 may be selected as a winding layer, on which adhesive or latex is provided, and the ball surface patch 3 is bonded with the winding layer through the adhesive or latex. As the further defined technical proposal of the invention, the winding layer is made of at least one of polyester-cotton yarn, cotton yarn, polyester yarn and nylon yarn by winding.

Specifically, the winding layer is made of yarns by winding and can form a tight and strong structure around the foamed ball core 1. This structure not only enhances the overall stability of the ball, and enables the ball to better disperse and resist the impact of external forces, thus extending the service life of the ball. The materials used in the winding layer, such as poly-cotton yarn, cotton yarn, polyester yarn or nylon yarn, have high strength and protection. These materials ensure that the winding layer has excellent durability and can maintain stable performance in the long time of use and frequent friction. Adhesive or latex is provided on the winding layer to firmly bond the ball surface patch 3 to the winding layer. This bonding method not only improves the bonding force between the ball surface patch 3 and the reinforcing layer 2, but also makes the ball better maintain the integrity of the whole structure under external forces. Moreover, the reinforcing layer 2 of the winding layer has greater flexibility and can adapt to the needs of different material combinations. For example, yarns of different materials and specifications can be selected to manufacture the winding layer to meet the ball performance requirements of different sports scenarios and athletes.

Further, in the embodiment, a single ball surface patch 3 comprises a foamed ball surface layer 3A and a film layer 3B connected successively, wherein the foamed ball surface layer 3A is bonded to the surface of the reinforcing layer 2. The foamed ball surface layer 3A is prepared by using the supercritical foaming process.

Specifically, the foamed ball surface layer 3A is prepared by using the supercritical foaming process. The special property of the supercritical process (such as carbon dioxide or nitrogen) at specific temperatures and pressures is utilized so that small irregular foam structures are formed in the foaming process of the materials. This structure offers the foamed ball surface layer 3A excellent elasticity, light weight and protection. In the embodiment, the foamed ball surface layer 3A may be made of at least one of a variety of materials, such as EVA, TPE, SBR, NBR, EPDM, SBL, POE, PE and TPR. These materials have their own characteristics and can be selected according to the use and performance requirements of the ball. For example, materials such as polyurethane and TPU have excellent elasticity and restorability as well as low temperature impact resistance, and are suitable for the production of high-end sports balls. Meanwhile, the foamed ball surface layer 3A is closely bonded to the surface of the reinforcing layer 2, forming the outer structure of the ball. This bonding method not only enhances the structural stability of the ball, but also enables the ball to better disperse and resist the impact of external forces.

In addition, the film layer 3B can be made of TPU, PVC, PU, TPE, TPR, PET, EVA and other materials. These materials have good flexibility, protection and chemical resistance, and can protect the foamed ball surface layer 3A from the external environment. The film layer 3B not only improves the durability of the ball, but also offers the ball better waterproof, dustproof and anti-fouling properties. This allows the ball to maintain stable performance in wet or harsh operating environments. Meanwhile, as the outer layer of the ball surface patch 3, the film layer 3B can form a printing layer on the surface of the film layer 3B through painting, printing, thermal transfer printing, water transfer printing or cold transfer printing, pad printing and other technologies; the printing layer can carry rich visual elements, such as pattern, logo, brand identity, etc. to improve the appearance and personalization of the ball.

As shown in FIG. 2 and FIG. 3, a single ball surface patch 3 can be designed as a regular hexagon, a regular pentagon or other polygons or irregular shapes. Multiple suitable ball surface patches 3 are bonded to the reinforcing layer 2 to form a tight ball surface, namely, a ball with different patterns; this design not only improves the appearance of the ball, but also enhances the structural stability and durability of the ball. Meanwhile, the shape of the ball surface patch can also be customized according to customer requirements (see FIG. 2 and FIG. 3) to meet the individual requirements.

The specific production process is shown as follows:

Step 1: Material Preparation:

Foamed ball core 1: material: TPU foamed material; a supercritical foaming process is used to ensure that foamed ball core 1 has high elasticity, low temperature resistance and excellent elasticity and restorability.

Reinforcing layer 2: winding layer; material: polyester cotton yarn; diameter: 1 mm; winding method: spiral winding; adhesive is used as bonding agent to closely bond the winding layer with the foamed ball core 1 closely.

Foamed ball surface layer 3A: material: TPU foamed material; thickness: 3 mm; size: matched with the reinforcing layer 2 to ensure complete coverage; the supercritical foaming process is adopted to give the ball surface patch 3 light weight and good elasticity.

Film layer 3B: material: TPU film; thickness: 0.1 mm; size: slightly larger than that of the foamed ball surface layer 3A, with 2 mm margin at the edge for bonding.

Printing layer: the pattern, logo or brand identity is printed in the film layer 3B by thermal transfer printing technology.

• • Step 2: Prepare the foamed ball core 1: put TPU materials into supercritical foaming equipment for foaming according to the existing supercritical foaming process parameters (as the supercritical foaming process is a process of the prior art, its process parameters and process flow are no longer discussed here; for details, refer to CN20241103A408.5 or CN202410925729.3, etc.), and prepare the foamed ball core 1.
  • Step 3: Use the winding layer as the reinforcing layer 2, wind the polyester cotton yarn around the foamed ball core 1 according to the above winding process parameters, and use the latex as the adhesive for fixing.
  • Step 4: Put the TPU materials into the supercritical foaming equipment, foam according to the conventional supercritical foaming process parameters to prepare the foamed ball surface layer 3A, cut the TPU film into a size slightly larger than the foamed ball surface layer, and reserve a margin of 2 mm; closely combine the film layer 3B with the foamed ball surface layer 3A by a hot pressing process to form the final ball surface patch 3.
  • Step 5: Bond the ball surface patch 3 with the winding layer by hot pressing (hot pressing temperature: 150° C., hot pressing pressure: 5 MPa, hot pressing time: 30 seconds, cooling time: 10 seconds) to ensure tight fitting, and then a complete ball structure is formed.
  • Step 6: Form grooves on the surface of the foamed ball surface layer 3A by hot pressing or other means. The grooves can be arranged on the outermost surface of the foamed ball surface layer 3A according to actual needs. The grooves are exquisitely designed and have multiple functions: on the one hand, they can significantly reduce the friction of the ball during rolling or moving, making the ball smoother and improving movement performance; on the other hand, the grooves also have the function of facilitating drainage, and can effectively prevent water from affecting the handling and performance of the ball especially in wet or rainy environments. In addition, the grooves also increase the grip feeling of the ball, and improve the user's stability and accuracy in catching, passing and other movements. Therefore, the groove design on the surface of the foamed ball surface layer 3A not only improves the practicability of the ball, but also brings a more excellent experience for the ball game.

Ball Consistency Performance Test:

I. Experimental Objective

This experiment aims to verify the difference in roundness consistency between the ball with the reinforcing layer prepared by the supercritical foaming technology (experimental group) and the traditional inflatable ball (control group) after use (such as impact and extrusion) through a comparison test. The performance of the two balls in maintaining shape stability is evaluated by measuring and comparing the roundness variations before and after use.

II. Experimental Materials

Samples of experimental group: three balls with a traditional skeleton structure prepared by the supercritical patch technology, with a diameter of about 15 cm, numbered A1, A2 and A3.

Samples of control group: three traditional inflatable balls, with a diameter of about 15 cm, numbered B1, B2 and B3.

III. Test Equipment and Tools

Durability tester (capable of simulating the impact, extrusion and other conditions of the ball in actual use) and roundness measuring instrument (see FIG. 6, with accuracy of 0.01 mm)

IV. Experimental Procedure

Pretreatment and Initial Measurement:

Leave all balls at room temperature for 24 hours to eliminate the effect of temperature differences on the experimental results. Use a roundness measuring instrument to measure multiple evenly distributed points on each ball, and record the initial roundness data for each point (i.e. the distance from the surface of the ball to the center of the ball). Use simulation test: respectively place the balls for the experimental group and the control group in the durability tester, set the impact frequency, strength and test time, and simulate the impact and extrusion of the balls in actual use. The test time can be set according to standard requirements, such as 4 hours, to ensure that the balls undergo adequate use simulation. Post-use measurement: after the test, take out and measure the balls again at the same measuring points on each ball using the roundness measuring instrument, and record the roundness data after use. Data recording and analysis: calculate the roundness change of each ball before and after use (that is, the difference between the roundness data after use and the initial roundness). Analyze and compare the differences in roundness consistency between the experimental group and the control group.

V. Experimental Data Output

Initial Roundness Data (Unit: Mm):

	Ball	Measuring	Measuring	Measuring	Average
	No.	point 1	point 2	point 3	roundness

	A1	75.00	75.01	74.99	75.00
	A2	75.02	75.00	75.03	75.02
	A3	74.98	75.00	75.01	74.99
	B1	75.00	75.01	74.98	74.99
	B2	75.01	75.00	75.02	75.01
	B3	74.99	75.00	74.97	74.99

Roundness Data After Use:

Ball	Measuring	Measuring	Measuring	Average	Roundness
No.	point 1	point 2	point 3	roundness	variation

A1	74.99	75.00	74.98	74.99	−0.01
A2	75.01	75.00	75.02	75.01	−0.01
A3	74.97	74.99	74.98	74.98	−0.01
B1	74.95	74.96	74.93	74.95	−0.04
B2	74.97	74.95	74.98	74.97	−0.04
B3	74.94	74.95	74.92	74.94	−0.05

It can be concluded from the experimental data that the roundness consistency of the ball with the traditional skeleton structure and the supercritical patch technology (experimental group) is better than that of the traditional inflatable ball (control group) after use simulation. The roundness variation of the ball in the experimental group is small, indicating that it can better maintain the shape stability under the conditions of impact and extrusion. This proves the effectiveness of the supercritical patch technology in improving the roundness consistency of the ball.

Resilience Experiment:

I. Experimental Objective

This experiment aims to verify whether the resilience of the ball structure based on the supercritical process (hereinafter referred to as the “experimental ball”) is better than that of the basketball or football (hereinafter referred to as the “control ball”) of the same size in the market.

II. Experimental Materials and Equipment

2.1 Experimental Materials

Experimental group: The ball structure based on the supercritical process in the embodiment 1 was used, with a diameter of 20.5 cm, the foamed ball core 2 was made of TPU foamed material, the ball surface patch layer 4 was also made of TPU foamed material, the reinforcing layer 3 was polyester-cotton yarn winding layer, and the film layer 5 was TPU film.

Control group: The inflatable football of the same size (20.5 cm) was randomly selected in the market, and may be made of polyvinyl chloride (PVC) or other rubber or plastic and rubber copolymer materials.

2.2 Experimental Equipment

High precision rebound resilience tester shown in FIG. 5: used to accurately measure the rebound height of the ball.

III. Experimental Procedure

Preparation Stage:

Ensure that the products in the experimental group and the control group are new and unused.

Use a height gauge to mark the height of 2.00 meters at the release point of each ball.

Test Stage:

Release each ball from the marked release point and let it fall free and rebound.

Use a rebound resilience tester to measure the rebound height of the ball when rebounding to its highest point.

Repeat this process 10 times to obtain stable experimental data.

Data Recording and Processing:

Record the rebound height in each test, and calculate the average rebound height and rebound rate (average rebound height/release height×100%). Perform statistical analysis on the data to verify whether the difference between the two groups of data is significant.

IV. Experimental Data

Bounce Test Report for Experimental Group

Test sample	Non-	Type of	S4	Temperature	26° C.	Humidity	50%
	inflatable	ball		(° C.)		(%)
	patch
	football

Test date

Dec.

Material

TPU

Code

Sample ball

	7, 2024
Circumference	643 MM	Weight	419 g	Gas pressure	/	Diameter	205
(MM)		(G)		(PSI)		(MM)

Inspection	1. Drop the ball 10 times from a height of 2 meters onto the steel plate and record
method	the average.

Detection

Maximum: 1351 MM

Minimum: 1267 MM

analysis	Rebound average: 1305 MM
	Bounce values after test: 1289, 1320, 1351, 1298, 1267, 1304, 1311, 1340, 1269,
	1305. (Unit: MM)

Bounce Test Report for Control Group

Test sample	Inflatable	Type of	S4	Temperature	26° C.	Humidity	50%
	patch	ball		(° C.)		(%)
	football

Test date

Dec.

Material

TPU

Code

Sample ball

	7, 2024
Circumference	643 MM	Weight	400 g	Gas pressure	12	Diameter	205
(MM)		(G)		(PSI)		(MM)

Inspection	1. Drop the ball 10 times from a height of 2 meters onto the steel plate and record
method	the average.

Detection

Maximum: 1247 MM

Minimum: 1103 MM

analysis	Rebound average: 1179 MM
	Bounce values after test: 1206, 1121, 1247, 1188, 1103, 1120, 1189, 1204, 1197,
	1215. (Unit: MM)

V. Data Analysis

The bounce test reports for the experimental group and the control group show that the average rebound height of the experimental ball is 1305 MM and the average rebound rate is 65.25%; the average rebound height of the control ball is 1179 MM and the average rebound rate is 58.95%, proving that the resilience of the experimental ball is significantly better than that of the control ball.

VI. Conclusion

This experiment verifies that the resilience of the ball structure based on the supercritical process is significantly better than that of the common football in the market. The experimental data show that the average rebound rate and height of the experimental ball are higher than that of the control ball, and the difference is significant.

See FIG. 4 for another group of experiments: rugby consistency retention experiment

I. Experimental Objective

This experiment aims to test the retention capability of the external shape (namely, the ball consistency) of the rugby prepared by the supercritical foaming technology (experimental group) under normal impact, extrusion and other forces, ensure that the surface of the ball has no obvious bumps or depressions compared with the control group (traditional rugby) under external forces, and maintain better ball shape consistency.

II. Experimental Materials

Samples for experimental group: 3 rugbies prepared by the supercritical foaming technology (rugbies prepared by using the process of the embodiment 1), with diameter and shape in line with rugby standards, numbered A1, A2 and A3.

Samples for control group: 3 rugby rugbies made by the traditional technology, with the same diameter and shape as the experimental group, numbered B1, B2 and B3.

Experimental Equipment:

Impact tester: capable of simulating the impact force and frequency of a rugby in the actual game.

Extrusion tester: used to simulate the force of a rugby when being squeezed.

Roundness measuring instrument: high precision measuring instrument, used to measure the roundness and surface shape changes of a rugby before and after use.

III. Experimental Procedure

Pretreatment: Leave all the rugbies at room temperature for 24 hours to eliminate the effect of temperature differences on the experimental results. Use a roundness measuring instrument to initially measure each rugby, and record its initial roundness and surface shape data.

Impact test: Place the rugbies for the experimental group and the control group in the impact tester respectively, and set the impact force and frequency in line with the actual situation of the rugby game. Perform a certain number of impact tests, and ensure that each rugby receives sufficient impact.

Squeeze test: Transfer the rugbies undergoing the impact test to the squeeze tester to simulate the force of the rugbies when being squeezed. Perform a certain number of squeeze tests, and record the force and duration of each squeeze.

Post-use measurement: Use a roundness measuring instrument to conduct post-use measurement for each rugby, and focus on changes in roundness and surface form. Record and compare the measured data of each rugby with the initial data.

Data analysis: Calculate the variations of roundness and surface form of each rugby before and after use.

Statistically analyze the data of the experimental group and the control group to compare the differences in ball consistency between the two groups.

IV. Experimental Data Output

	Initial	Roundness	Roundness	Description of
Ball	roundness	after use	variation	surface form
No.	(mm)	(mm)	(mm)	change

A1	75.00	74.99	−0.01	No obvious
				bump or
				depression
A2	75.01	75.00	−0.01	No obvious
				bump or
				depression
A3	74.99	74.98	−0.01	No obvious
				bump or
				depression
B1	75.00	74.95	−0.05	Slight
				depression
B2	75.02	74.97	−0.05	Slight bump
B3	74.98	74.93	−0.05	Slight
				depression

V. Experimental Conclusion

It can be concluded from the above experimental data that the retention capability of the external shape (ball consistency) of the rugby prepared by the supercritical foaming technology (experimental group) is significantly better than that of the rugby prepared by the traditional process (control group) under normal impact, extrusion and other forces. In the experimental group, the roundness variation of the rugby was small, and the surface shape had no obvious bump or depression, indicating that the ball could maintain the shape consistency of the ball under external force. However, in the control group, different degrees of roundness and surface shape changes occurred, indicating that there were deficiencies in ball consistency. Therefore, the rugby prepared by the supercritical patch technology has significant advantages in improving ball consistency and durability.

The above embodiments are only intended to describe the preferred embodiments of the invention, but not to limit the scope of the invention. Various variations and improvements made by ordinary engineering technicians in the field for the technical proposal of the invention without deviation from the design spirit of the invention shall fall within the scope of protection determined by the claims of the invention.