Production process of sticky rubber ball and sticky rubber ball

Abstract

The application relates to the technical field of sports goods, and particularly discloses a production process of a sticky rubber ball and the sticky rubber ball. The production process of the sticky rubber ball and the sticky rubber ball comprises the following steps: (1) mixing raw rubber, a toughening agent, a filling agent and a vulcanizing agent to obtain premix, performing glue removal of the premix after mixing at 120-130 DEG C to obtain a glue material; (2) mixing naphthenic oil and a microsphere foaming agent and then performing spray processing to obtain a powder-oil mixture; (3) mixing the glue material, a crosslinking agent and the powder-oil mixture, performing glue removal after mixing at 70-80 DEG C to obtain foamable glue material; and (4) performing injection molding processing by taking the foamable glue material as raw material to obtain a foamed ball skin, bonding the foamed ball skin on an inflating inner tube wrapped with polyester fabric to obtain the sticky rubber ball. The application reduces the possibility of water residues on the surface of the ball skin, helps to improve the anti-skid performance of the rubber ball, and improves the sticky feeling of the rubber ball.

Description

Technical Field

[0001] This application relates to the field of sporting goods technology, and more specifically, to a manufacturing process for a sticky rubber ball and the sticky rubber ball itself. Background Technology

[0002] Ball sports hold an important place in the field of sports, with volleyball, basketball, and football collectively known as the "Big Three." The structure of a basketball currently used in sports includes an inner bladder and a outer shell. The outer shell is the side of the basketball that directly contacts the outside environment, and its performance directly determines the basketball's performance. Basketball shells can be made of PU, genuine leather, or rubber; basketballs with rubber outer shells are also called rubber balls.

[0003] One related technology involves a rubber ball composed of an inner bladder and a outer shell. The outer shell is primarily made of natural rubber. The rubber ball is produced using the following process: (1) Natural rubber raw material, toughening agent, filler, and vulcanizing agent are mixed to obtain a premix. After mixing, the premix is ​​discharged at 120-130℃ to obtain a rubber compound; (2) The rubber compound is mixed and discharged at 70-80℃ to obtain a rubber compound; (3) Using the rubber compound as raw material, injection molding is performed at 160-200℃ to obtain a outer shell. The outer shell is then bonded to an inflatable inner tube wrapped with polyester fabric to obtain a rubber ball. During the processing, the surface of the outer shell is squeezed by the mold to form protrusions several millimeters in diameter. The presence of these protrusions gives the rubber ball a certain degree of anti-slip properties.

[0004] Regarding the aforementioned technologies, the inventors believe that although the protrusions on the surface of the rubber ball in the aforementioned technologies can play a certain role in preventing slippage, the size of the protrusions is difficult to further reduce due to the limited precision of the production mold, which limits the improvement of the anti-slip performance of the rubber ball. Summary of the Invention

[0005] In related technologies, the size of the protrusions on the surface of rubber balls is difficult to further reduce, limiting the improvement of the anti-slip performance of rubber balls. To overcome this deficiency, this application provides a manufacturing process for a sticky rubber ball and a sticky rubber ball itself.

[0006] Firstly, this application provides a manufacturing process for a sticky rubber ball, employing the following technical solution:

[0007] A manufacturing process for a sticky rubber ball includes the following steps:

[0008] (1) Mix raw rubber, toughening agent, filler and vulcanizing agent to obtain premix. After mixing, the premix is ​​discharged at 120-130℃ to obtain rubber compound.

[0009] (2) The naphthenic oil is mixed with the microsphere foaming agent and then sprayed to obtain a powder-oil mixture; in this step, the mass fraction of naphthenic oil in the powder-oil mixture is 8-10%;

[0010] (3) Mix the rubber compound, crosslinking agent and powder oil mixture, and after kneading, discharge the rubber at 70-80℃ to obtain a foamable rubber compound. (4) Use the foamable rubber compound as raw material and perform injection molding at 160-200℃ to obtain a foamed ball skin. Adhere the foamed ball skin to an inflatable inner tube wrapped with polyester fabric to obtain a sticky rubber ball.

[0011] By adopting the above technical solution, this application uses a microsphere foaming agent to foam the skin of the rubber ball. After foaming, a large number of micropores with a size of tens of micrometers are generated on the surface of the rubber ball skin. Since the micropore size of this application is much smaller than the diameter of the protrusions in related technologies, the rubber ball skin of this application has a larger surface area than the rubber ball skin in related technologies. When the user's palms become wet due to factors such as sweating, the micropores can absorb the moisture from the user's palms in time, thereby reducing the possibility of moisture remaining on the surface of the ball skin, which helps to improve the anti-slip performance of the rubber ball and enhances its stickiness.

[0012] Preferably, the raw rubber comprises at least one of brominated butyl rubber, chloroprene rubber, and carboxylated nitrile rubber.

[0013] By adopting the above technical solution, this application has optimized the components of the raw rubber. Carboxylated nitrile rubber can introduce nitrile and carboxyl groups into the rubber ball's skin, while chloroprene rubber and brominated butyl rubber can introduce halogen atoms into the rubber ball's skin. The strong polarity of nitrile and carboxyl groups and the high viscosity of halogen atoms can further improve the anti-slip performance of the rubber ball's skin, reduce the rubber ball's slippage, and improve the rubber ball's sticky feel.

[0014] Preferably, the raw rubber comprises 20-30 parts by weight of brominated butyl rubber, 20-30 parts by weight of chloroprene rubber, and 60-70 parts by weight of carboxylated nitrile rubber.

[0015] By adopting the above technical solution, this application optimizes the dosage of brominated butyl rubber, chloroprene rubber, and carboxylated nitrile rubber, which helps to improve the stickiness of the rubber ball.

[0016] Preferably, the filler is sodium polyacrylate.

[0017] While the ball skin made of polar rubber has a certain degree of permeability, it cannot store excessive moisture because the water is difficult to dissipate once it enters the skin. Sodium polyacrylate, however, can store moisture and allow it to continuously permeate the skin through timely moisture absorption. When a player's sweat causes some moisture to seep into the skin, sodium polyacrylate can hydrate this moisture, thus storing it, reducing the amount of residual moisture on the rubber ball's surface, helping to reduce slippage, and improving the ball's sticky feel.

[0018] Preferably, the raw rubber component also includes 8-12 parts by weight of natural rubber.

[0019] By adopting the above technical solution, the compounding of natural rubber and brominated butyl rubber will reduce the air tightness of brominated butyl rubber. Therefore, it is easier for moisture on the surface of the rubber ball and the moisture generated by moisture evaporation to enter the ball skin, which improves the moisture absorption performance of the ball skin and enhances the stickiness of the rubber ball.

[0020] Preferably, the toughening agent is acrylic fiber.

[0021] By adopting the above technical solution, acrylic fibers increase the total content of acrylic groups in the ball skin. The strong polarity of acrylic groups can enhance the anti-slip performance of the rubber ball skin. Therefore, the incorporation of acrylic fibers reduces the slippage of the rubber ball and improves its sticky feel. In addition, acrylic fibers can be processed from waste acrylic textiles, thus contributing to the recycling of waste materials.

[0022] Preferably, the amount of acrylic fiber used is 6-8% of the total weight of the raw rubber.

[0023] By adopting the above technical solution, the amount of acrylic fiber used is optimized, which helps to reduce the slippage of the rubber ball and improve the stickiness of the rubber ball.

[0024] Preferably, the filler is activated carbon.

[0025] By adopting the above technical solution, the incorporation of activated carbon is beneficial to the formation of pits on the surface of the ball, thereby increasing the total surface area of ​​the pits, improving the anti-slip performance of the ball, and improving the stickiness of the rubber ball.

[0026] Preferably, the amount of activated carbon used is 2.4-2.6% of the weight of the raw rubber.

[0027] By adopting the above technical solution, the optimal range of activated carbon dosage is selected, which helps to enhance the anti-slip performance of the ball skin and the stickiness of the rubber ball.

[0028] Secondly, this application provides a sticky rubber ball, which adopts the following technical solution.

[0029] A sticky rubber ball is produced according to the above-mentioned production process for sticky rubber balls.

[0030] By adopting the above technical solution, the rubber balls produced according to the above process have low precision requirements for the mold. Not only can micropores with moisture absorption effect be obtained directly through microsphere foaming agent, but there is also no need to use a mold with depressions on the surface to generate protrusions, which reduces the processing difficulty of the mold and reduces the change in protrusion size caused by mold wear.

[0031] In summary, this application has the following beneficial effects:

[0032] 1. The process of this application, by adding a microsphere foaming agent to the formula of the ball skin, creates a large number of micropores on the surface of the microspheres. The micropores can absorb moisture from the user's palm in time, thereby reducing the possibility of moisture remaining on the surface of the ball skin, which helps to improve the anti-slip performance of the rubber ball and improve the stickiness of the rubber ball.

[0033] 2. In the process of this application, the preferred components of the raw rubber include at least one of brominated butyl rubber, chloroprene rubber, and carboxylated nitrile rubber, thus achieving the introduction of nitrile groups and halogen atoms. The strong polarity of the nitrile groups and the high viscosity of the halogen atoms can further improve the anti-slip performance of the rubber ball skin, reduce the slippage of the rubber ball, and improve the stickiness of the rubber ball.

[0034] 3. This application directly obtains micropores with moisture absorption effect through microsphere foaming agent, without the need to generate protrusions through special molds with recessed surfaces. This not only reduces the processing difficulty of the mold, but also reduces the changes in the size of the protrusions caused by mold wear. Detailed Implementation

[0035] The present application will be further described in detail below with reference to the embodiments, preparation examples and comparative examples. The raw materials involved in the present application can all be obtained commercially.

[0036] Example

[0037] Examples 1-5

[0038] The following description uses Example 1 as an example.

[0039] Example 1

[0040] In this embodiment, the sticky rubber ball is prepared according to the following steps:

[0041] (1) The raw rubber, toughening agent, filler and vulcanizing agent are mixed to obtain a premix. After the premix is ​​compounded, it is discharged at 125°C to obtain a rubber compound. In this step, the raw rubber consists of 200g of brominated butyl rubber, 200g of chloroprene rubber and 600g of carboxylated nitrile rubber. The toughening agent is glass fiber, and the amount of toughening agent is 5% of the weight of the raw rubber. The filler is silica, and the amount of filler is 2.3% of the weight of the raw rubber. The vulcanizing agent is industrial sulfur, and the amount of vulcanizing agent is 4% of the weight of the raw rubber.

[0042] (2) The naphthenic oil was mixed with 50g of microsphere foaming agent and then sprayed to obtain a powder-oil mixture; in this step, the mass fraction of naphthenic oil in the powder-oil mixture was 8%; in this step, Akzo microsphere foaming agent was selected.

[0043] (3) Mix the rubber compound and the powder oil mixture, and after kneading, discharge the rubber at 75°C to obtain a foamable rubber compound.

[0044] (4) Using foamable rubber material as raw material, injection molding is carried out at 180°C to obtain foamed ball skin. The foamed ball skin is then bonded to an inflatable inner tube wrapped with polyester fabric to obtain a sticky rubber ball.

[0045] As shown in Table 1, the main difference between Examples 1-5 lies in the different raw material ratios of the rubber.

[0046] Table 1

[0047] sample Brominated butyl rubber / g Chloroprene rubber / g Carboxylated acrylonitrile rubber / g Example 1 200 200 600 Example 2 220 220 620 Example 3 250 250 650 Example 4 280 280 680 Example 5 300 300 700

[0048] Example 6

[0049] The difference between this embodiment and Embodiment 4 is that brominated butyl rubber and chloroprene rubber are replaced with carboxylated nitrile rubber.

[0050] Example 7

[0051] The difference between this embodiment and Embodiment 4 is that brominated butyl rubber and carboxylated nitrile rubber are replaced with chloroprene rubber.

[0052] Example 8

[0053] The difference between this embodiment and Embodiment 4 is that chloroprene rubber and carboxylated nitrile rubber are replaced with brominated butyl rubber.

[0054] Example 9

[0055] The difference between this embodiment and Embodiment 4 is that sodium polyacrylate is used as the filler.

[0056] Example 10

[0057] The difference between this embodiment and Embodiment 9 is that the raw rubber component also includes 70g of natural rubber.

[0058] As shown in Table 2, the difference between Examples 10-14 is the amount of natural rubber used.

[0059] Table 2. Amount of Natural Rubber Used

[0060] sample Example 10 Example 11 Example 12 Example 13 Example 14 Natural rubber / g 70 80 100 120 130

[0061] Example 15

[0062] The difference between this embodiment and Embodiment 4 is that the toughening agent is acrylic fiber.

[0063] As shown in Table 3, the difference between Examples 15-19 lies in the percentage of acrylic fiber used relative to the weight of the raw rubber.

[0064] Table 3. Percentage of acrylic fiber usage by weight of raw rubber

[0065] sample Example 15 Example 16 Example 17 Example 18 Example 19 Acrylic fiber percentage 5 6 7 8 9

[0066] Example 20

[0067] The difference between this embodiment and Embodiment 4 is that activated carbon is used as the filler.

[0068] As shown in Table 4, the difference between Examples 20-24 lies in the percentage of activated carbon used relative to the weight of the raw rubber.

[0069] Table 4. Percentage of activated carbon used by weight of raw rubber

[0070] sample Example 20 Example 21 Example 22 Example 23 Example 24 Activated carbon percentage 2.3 2.4 2.5 2.6 2.7

[0071] Comparative Example

[0072] Comparative Example 1

[0073] A rubber ball is composed of an inner bladder and a ball skin. The main component of the ball skin is natural rubber. The rubber ball is produced according to the following process: (1) Natural rubber raw rubber, toughening agent, filler and vulcanizing agent are mixed to obtain a premix. After the premix is ​​mixed, the glue is discharged at 125°C to obtain a rubber compound; (2) The rubber compound is mixed and discharged at 75°C to obtain a rubber compound; (3) The rubber compound is used as raw material and injection molded at 180°C to obtain a ball skin. The ball skin is then bonded to an inflatable inner tube wrapped with polyester fabric to obtain a rubber ball.

[0074] In this comparative example, the toughening agent is glass fiber, and the amount of toughening agent is 5% of the weight of raw rubber; the filler is silica, and the amount of filler is 2.3% of the weight of raw rubber; the vulcanizing agent is industrial sulfur, and the amount of vulcanizing agent is 4% of the weight of raw rubber.

[0075] Comparative Example 2

[0076] The difference between this comparative example and Example 3 is that the raw rubber component only includes natural rubber.

[0077] Performance testing methods

[0078] Sampling of the ball skin was performed according to GB / T 10006-2021 "Determination of Coefficient of Friction of Plastic Films and Sheets", at a rate of 2 L / (min·m 2 Water mist was sprayed onto the sample surface at a rate of 1 min. Immediately after spraying, the static friction coefficient of the ball skin was measured. After all the measurements were completed, the ratio of the static friction coefficient of each embodiment and comparative example to the static friction coefficient of Comparative Example 1 was calculated. The results were expressed as a percentage and recorded as the relative friction coefficient. The results are shown in Table 5.

[0079] Table 5

[0080] sample relative friction coefficient / % sample relative friction coefficient / % Example 1 137.3 Example 14 147.5 Example 2 138.5 Example 15 143.6 Example 3 139.2 Example 16 143.9 Example 4 139.4 Example 17 144.2 Example 5 138.9 Example 18 144.3 Example 6 132.8 Example 19 144.3 Example 7 130.4 Example 20 149.8 Example 8 131.7 Example 21 150.6 Example 9 142.5 Example 22 151.3 Example 10 146.3 Example 23 151.6 Example 11 146.9 Example 24 151.8 Example 12 147.2 Comparative Example 1 100.0 Example 13 147.4 Comparative Example 2 126.9

[0081] Combining Examples 1-5 and Comparative Examples 1-2 with Table 5, it can be seen that the relative coefficients of friction measured in Examples 1-5 and Comparative Example 2 are higher than those in Comparative Example 1. This indicates that Examples 1-5 and Comparative Example 2 both achieved water absorption through the micropores formed by the microsphere foaming agent, reducing the water retained on the ball surface, improving the anti-slip performance of the ball, and enhancing the stickiness of the rubber ball. In contrast, although the polar rubber component has a better affinity for water, simply replacing the non-polar rubber with a polar rubber cannot significantly improve the anti-slip performance of the ball. Therefore, the main improvement effect in Examples 1-5 comes from the micropores generated by the microsphere foaming agent.

[0082] In Examples 1-5, with the changes in formulation, the relative content of carboxylated nitrile rubber gradually decreased, and its contribution to the relative coefficient of friction (mainly increasing the polarity of the ball skin) also gradually decreased. The relative contents of brominated butyl rubber and chloroprene rubber gradually increased, therefore their contributions to the relative coefficient of friction (mainly increasing the stickiness of the ball skin) also gradually increased. In Example 4, the contributions of carboxylated nitrile rubber, brominated butyl rubber, and chloroprene rubber to the relative coefficient of friction were nearly balanced, thus the results obtained in Examples 1-5 were the largest. Compared to Example 4, Example 5 had too little carboxylated nitrile rubber and too much brominated butyl rubber and chloroprene rubber, therefore the results actually decreased.

[0083] Combining Examples 4 and 6-8 with Table 5, it can be seen that when brominated butyl rubber, chloroprene rubber, and carboxylated nitrile rubber are compounded together, the ball shell contains not only highly polar nitrile and carboxyl groups, but also halogen atoms that can increase adhesion. Examples 6-8, however, only exhibit one of these two mechanisms. Under the synergistic effect of the two mechanisms, the relative coefficient of friction in Example 4 is significantly higher than that in Examples 6-8.

[0084] As can be seen from Examples 4 and 9 and Table 5, sodium polyacrylate allows water to continuously penetrate into the ball skin by timely consuming water, thus achieving water storage, reducing the amount of residual water on the surface of the rubber ball, helping to reduce the slippage of the rubber ball, and improving the stickiness of the rubber ball.

[0085] Combining Examples 4 and 10-14 with Table 5, it can be seen that adding a small amount of natural rubber to the rubber ball in Example 4 reduces the airtightness of the brominated butyl rubber. This allows moisture on the surface of the rubber ball, as well as moisture generated by evaporation, to more easily penetrate the ball's shell, improving its hygroscopic properties and reducing moisture retention. This not only increases the relative coefficient of friction of the ball's shell but also enhances the stickiness of the rubber ball.

[0086] As can be seen from Examples 4 and 15-19, and Table 5, using acrylic fiber as a toughening agent increases the total content of acrylic groups. The strong polarity of the acrylic groups enhances the anti-slip performance of the rubber ball skin, reduces slippage, and improves the stickiness of the rubber ball. When the amount of acrylic fiber exceeds 8% of the total weight of the raw rubber, the improvement in the relative coefficient of friction brought by the acrylic fiber is not significant. Therefore, the preferred dosage range is 6-8% of the total weight of the raw rubber.

[0087] As can be seen from Examples 4, 20-24, and Table 5, the addition of activated carbon is beneficial to the formation of pits on the surface of the ball, increasing the total surface area of ​​the pits, improving the anti-slip performance of the ball, and improving the stickiness of the rubber ball. However, as the amount of activated carbon increases, the improvement in the relative coefficient of friction becomes less and less significant. Therefore, the preferred dosage range is 2.4-2.6% of the weight of the raw rubber.

[0088] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A manufacturing process for a sticky rubber ball, characterized in that, Includes the following steps: (1) Mix raw rubber, toughening agent, filler and vulcanizing agent to obtain premix, and after mixing, discharge the premix at 120-130℃ to obtain rubber compound; (2) The naphthenic oil is mixed with the microsphere foaming agent and then sprayed to obtain a powder-oil mixture; in this step, the mass fraction of naphthenic oil in the powder-oil mixture is 8-10%; (3) Mix the rubber compound, crosslinking agent and powder oil mixture, and after kneading, discharge the rubber at 70-80℃ to obtain a foamable rubber compound; (4) Using foamable rubber material as raw material, injection molding is carried out at 160-200℃ to obtain foamed ball skin. The foamed ball skin is then bonded to an inflatable inner tube wrapped with polyester fabric to obtain a sticky rubber ball.

2. The production process of the sticky rubber ball according to claim 1, characterized in that, The raw rubber comprises at least one of brominated butyl rubber, chloroprene rubber, and carboxylated nitrile rubber.

3. The production process of the sticky rubber ball according to claim 2, characterized in that, The raw rubber comprises 20-30 parts by weight of brominated butyl rubber, 20-30 parts by weight of chloroprene rubber, and 60-70 parts by weight of carboxylated nitrile rubber.

4. The production process of the sticky rubber ball according to claim 3, characterized in that, The filler used is sodium polyacrylate.

5. The production process of the sticky rubber ball according to claim 4, characterized in that, The raw rubber also includes 8-12 parts by weight of natural rubber.

6. The production process of the sticky rubber ball according to claim 1, characterized in that, The toughening agent is made of acrylic fiber.

7. The production process of the sticky rubber ball according to claim 6, characterized in that, The amount of acrylic fiber used is 6-8% of the total weight of the raw rubber.

8. The production process of the sticky rubber ball according to claim 1, characterized in that, The filler is activated carbon.

9. The production process of the sticky rubber ball according to claim 8, characterized in that, The amount of activated carbon used is 2.4-2.6% of the weight of the raw rubber.