Environment-friendly crystal billiard ball based on epoxy resin

Abstract

The invention relates to the technical field of sporting goods manufacturing, and discloses an epoxy resin-based environment-friendly crystal billiard ball which is composed of a ball core and an outer coating layer, and the preparation steps sequentially comprise raw material pretreatment, ball core forming, secondary pouring coating, curing, post-processing and surface treatment. The raw material pretreatment comprises base material system configuration, filler treatment and mixed slurry preparation, the base material system takes epoxy resin as matrix resin and is matched with an amino curing agent, the mass ratio of the epoxy resin to the curing agent is 100: (25-30), the filler comprises 2800-3500-mesh barium sulfate powder, a nanoscale inorganic filler and high-mesh silica powder of which the mesh number is greater than or equal to 20000 meshes, and the mixed slurry is prepared from the following raw materials in parts by weight. The mixed slurry is divided into ball core slurry and coating layer slurry which are both stirred and dispersed by a high-speed dispersion machine, and a segmented heating curing process is adopted for curing. The process parameters are clear and controllable, the method is suitable for large-scale production, the raw materials are easy to obtain, the cost is controllable, and the method has a good market application prospect.

Description

Technical Field

[0001] This invention relates to the field of sporting goods manufacturing technology, specifically to environmentally friendly crystal billiard balls based on epoxy resin. Background Technology

[0002] Billiards, as a widely popular recreational sport, has penetrated entertainment venues, fitness clubs, and home entertainment settings. Its performance directly impacts the gaming experience and safety, leading to continuously increasing market demands for the appearance, structural stability, and environmental friendliness of billiard balls. Crystal billiard balls, with their high transparency, wear resistance, and impact resistance, have become the mainstream choice and are widely used in various competitive and recreational settings.

[0003] Most crystal billiard balls are currently manufactured using phenolic resin or unsaturated polyester resin as the base material. To improve molding performance and appearance, some production processes introduce harmful substances containing benzene, or the resin system used may release volatile organic compounds during curing. These harmful components remain inside the billiard ball for a long time and slowly evaporate during use, not only polluting the indoor environment but also posing potential harm to the user's respiratory tract and skin. This is especially true in enclosed entertainment venues, where the accumulation of harmful substances can easily lead to health risks.

[0004] With increasingly stringent environmental regulations and rising consumer health awareness, the market acceptance of traditional harmful crystal billiard balls is gradually declining. Developing environmentally friendly crystal billiard balls that are benzene-free, low in VOCs emissions, and meet or even exceed performance standards has become the key to solving the health hazards of existing products and meeting market demands, and has significant industrial value and social significance. Summary of the Invention

[0005] The purpose of this invention is to overcome the defects of existing crystal billiard balls in terms of harmful component residue and volatilization, and to provide an environmentally friendly crystal billiard ball based on epoxy resin. By optimizing the selection of substrate and preparation process, it achieves environmental protection and harmlessness while taking into account the mechanical properties, appearance and texture and service life of the product, and unexpectedly improves the product's resistance to yellowing and dimensional stability.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: An environmentally friendly crystal billiard ball based on epoxy resin is characterized by comprising a core and an outer coating layer. The manufacturing process includes raw material pretreatment, core molding, secondary casting and coating, curing, post-processing, and surface treatment, as detailed below: 1. Raw material pretreatment (1) Substrate system: Bisphenol A epoxy resin is used as the matrix resin and diaminodicycloethylmethane is used as the curing agent. The mass ratio of epoxy resin to curing agent is 100:25-30. (2) Filler treatment: Barium sulfate powder is sieved through a 2800-3500 mesh sieve and then dried in a 120℃ oven for 4-6 hours to remove moisture; fumed alumina nanomaterials and 20000 mesh silicon micro powder are dried for 2-3 hours respectively and set aside. (3) Preparation of mixed slurry: Core slurry: By mass fraction, take 60%-70% epoxy resin, 15%-18% curing agent, 12%-20% barium sulfate powder, and 2%-5% fumed alumina nanomaterials, add them to a high-speed disperser, and stir for 30-40 minutes at a speed of 1500-2000 r / min and a temperature of 40-50℃ to obtain a uniformly dispersed core slurry; Coating slurry: By mass fraction, take 65%-75% epoxy resin, 16%-19% curing agent, 8%-15% 20000 mesh silica powder, and 1%-3% fumed silica, add them to a high-speed disperser, and stir for 40-50 minutes at a speed of 1800-2200 r / min and a temperature of 35-45℃. Then filter through a 300 mesh filter to remove impurities and obtain the coating slurry.

[0007] 2. Core forming Inject the spherical core slurry into a spherical silicone mold and allow it to stand for 8-12 hours to pre-cure at a temperature of 25-30℃ and a humidity of 40%-60%. Then, raise the temperature to 50-60℃ and keep it at that temperature for 16-20 hours to cure. After demolding, the ball core is turned and ground to a round shape using a ball grinder, controlling the diameter of the ball core to be 28-30mm and the roundness error to be ≤0.02mm.

[0008] 3. Secondary casting and covering Fix the polished ball core to the center of the spherical silicone mold for coating, ensuring that the distance between the ball core and the inner wall of the mold is uniform (3-4mm). Slowly inject the coating slurry into the mold to avoid generating air bubbles; After injection, allow it to stand for 6-8 hours at a temperature of 20-25℃ and a humidity of 45%-55% to perform preliminary leveling.

[0009] 4. Curing treatment The mold is then placed into the curing oven, where a staged heating and curing process is employed. First stage: Raise the temperature from room temperature to 45℃ at a rate of 2℃ / h and hold for 10 hours; Second stage: Heat to 65-70℃ at a rate of 3℃ / h and hold for 18-24 hours; Third stage: Allow the temperature to cool naturally to room temperature at a rate of ≤5℃ / h to complete the curing process.

[0010] 5. Post-processing and surface treatment (1) After demolding, the surface of the ball is rough machined using a precision lathe to remove the mold overflow and control the diameter of the ball to 38.5-38.8 mm; (2) After fine grinding with a spherical grinding machine, polish with 800 grit, 1500 grit and 3000 grit sandpaper in sequence until the surface roughness Ra of the sphere is ≤0.01μm; (3) If it is necessary to engrave the logo, use a laser engraving machine to engrave at the designated position with an engraving depth of 0.1-0.2mm; (4) Finally, wipe the surface of the ball with anhydrous ethanol to remove impurities and obtain an environmentally friendly crystal billiard ball based on epoxy resin.

[0011] Preferably, the bisphenol A epoxy resin has an epoxy value of 0.51-0.54 eq / 100g and a viscosity (25℃) of 8000-12000 mPa·s.

[0012] Preferably, the barium sulfate powder has a purity of ≥99.5%, a whiteness of ≥95, and the fumed alumina nanomaterial has a particle size of 20-50 nm and a specific surface area of ​​100-150 m² / g.

[0013] Preferably, the 20,000-mesh silica powder has a purity of ≥99.8%, a particle size of ≤0.7μm, and good light transmittance and dispersibility.

[0014] Preferably, the environmentally friendly crystal billiard ball has a diameter of 38.6-38.8mm, a roundness error of ≤0.03mm, a weight of 150-160g, no benzene residue, VOCs emission of ≤0.1mg / m³, tensile strength of ≥35MPa, Shore hardness (Type D) of ≥85, and a yellowing index of ≤1.5 after 1000 hours of ultraviolet aging test.

[0015] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. This invention uses a benzene-free bisphenol A epoxy resin system, eliminating harmful components in traditional processes. By optimizing the selection of curing agents and fillers, the product is free of benzene residue, and the VOCs emission level is far below the industry standard. This fundamentally solves the health hazards of existing billiard balls and achieves the core goal of being environmentally friendly and harmless. 2. This invention, through the composite filling and segmented curing process of fumed alumina nanomaterials and high-mesh silica powder, not only improves the mechanical properties of the sphere, but also significantly improves its resistance to yellowing and dimensional stability, solving the industry pain point of crystal billiard balls being prone to yellowing and deformation after long-term use. 3. In the preparation process of this invention, the filler is dried at high temperature and dispersed at high speed, combined with secondary casting and fine polishing to ensure that the surface of the ball is smooth and bright, with a transparency of over 90%, and the appearance and texture are superior to traditional resin billiard balls.

[0016] 4. The process parameters of this invention are clear and controllable, suitable for large-scale production, and the raw materials are readily available and the cost is controllable, which has good market application prospects. Detailed Implementation

[0017] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0018] Example 1

[0019] Raw material preparation: Bisphenol A epoxy resin (epoxy value 0.52 eq / 100g, viscosity 10000 mPa・s); Curing agent: diaminodicycloethylmethane; Fillers: Barium sulfate powder (3000 mesh, 99.6% purity), fumed alumina nanomaterials (30nm, specific surface area 120m² / g), 20000 mesh silica powder (99.8% purity), fumed silica (specific surface area 200m² / g).

[0020] Preparation process: Raw material pretreatment: Barium sulfate powder was sieved through a 3000-mesh sieve and dried at 120°C for 5 hours. Fumed alumina nanomaterials and 20000-mesh silica powder were dried at 120°C for 2.5 hours each. Core slurry: 65% epoxy resin, 16% curing agent, 15% barium sulfate powder, 4% fumed alumina nanomaterials, stirred for 35 minutes at 2000 r / min and 45℃ using a high-speed disperser; Coating slurry: 70% epoxy resin, 17% curing agent, 10% 20,000 mesh silica powder, 3% fumed silica. Stirred for 45 minutes at 2000 r / min and 40℃ using a high-speed disperser, and filtered through a 300 mesh filter.

[0021] Ball core molding: The slurry is injected into the mold, pre-cured at 28℃ and 50% humidity for 10 hours, and then cured at 55℃ for 18 hours. After demolding, it is ground to a diameter of 29mm with a roundness error of 0.015mm.

[0022] Secondary casting and coating: The ball core is fixed in the center of the mold, the coating slurry is injected, and it is left to stand at 23°C and 50% humidity for 7 hours.

[0023] Curing process: Keep warm at 45℃ for 10 hours → Keep warm at 68℃ for 20 hours → Allow to cool naturally to room temperature.

[0024] Post-processing: rough machining to a diameter of 38.7mm, followed by three-stage grinding and polishing, laser engraving of markings, and wiping with anhydrous ethanol.

[0025] Example 2

[0026] Raw material preparation: Same as in Example 1.

[0027] Preparation process: Raw material pretreatment: Barium sulfate powder was sieved through a 3200-mesh sieve and dried at 120°C for 6 hours. Fumed alumina nanomaterials and 20000-mesh silica powder were dried at 120°C for 3 hours each. Core slurry: 62% epoxy resin, 15% curing agent, 18% barium sulfate powder, 5% fumed alumina nanomaterials, stirred for 38 minutes at 1800 r / min and 48℃ using a high-speed disperser; Coating slurry: 68% epoxy resin, 18% curing agent, 12% 20,000 mesh silica powder, 2% fumed silica. Stirred for 48 minutes at 2200 r / min and 42℃ using a high-speed disperser, and filtered through a 300 mesh filter.

[0028] Ball core molding: The slurry is injected into the mold, pre-cured at 27℃ and 55% humidity for 11 hours, and then kept at 58℃ for 19 hours for curing. After demolding, it is ground to a diameter of 28.5mm with a roundness error of 0.01mm.

[0029] Secondary casting and coating: The ball core is fixed in the center of the mold, the coating slurry is injected, and it is left to stand at 24℃ and 52% humidity for 6.5 hours.

[0030] Curing process: Keep warm at 45℃ for 10 hours → Keep warm at 70℃ for 22 hours → Allow to cool naturally to room temperature.

[0031] Post-processing: rough machining to a diameter of 38.6mm, followed by three-stage grinding and polishing, laser engraving of markings, and wiping with anhydrous ethanol.

[0032] Example 3

[0033] Raw material preparation: Same as in Example 1.

[0034] Preparation process: Raw material pretreatment: Barium sulfate powder was sieved through a 2800-mesh sieve and dried at 120°C for 4 hours. Fumed alumina nanomaterials and 20000-mesh silica powder were dried at 120°C for 2 hours each. Core slurry: 68% epoxy resin, 17% curing agent, 13% barium sulfate powder, 2% fumed alumina nanomaterials, stirred for 32 minutes at 1600 r / min and 42℃ using a high-speed disperser; Coating slurry: 72% epoxy resin, 16% curing agent, 10% 20,000 mesh silica powder, 2% fumed silica. Stirred for 42 minutes at 1900 r / min and 38℃ using a high-speed disperser, and filtered through a 300 mesh filter.

[0035] Ball core molding: The slurry is injected into the mold, pre-cured at 30℃ and 45% humidity for 9 hours, and then cured at 52℃ for 17 hours. After demolding, it is ground to a diameter of 29.5mm with a roundness error of 0.02mm.

[0036] Secondary casting and coating: The ball core is fixed in the center of the mold, the coating slurry is injected, and it is left to stand at 22℃ and 48% humidity for 7.5 hours.

[0037] Curing process: Keep warm at 45℃ for 10 hours → Keep warm at 65℃ for 24 hours → Allow to cool naturally to room temperature.

[0038] Post-processing: rough machining to a diameter of 38.8mm, followed by three-stage grinding and polishing, laser engraving of markings, and wiping with anhydrous ethanol.

[0039] Comparative Example 1 (Traditional Phenolic Resin System) Raw material preparation: Substrate: Phenolic resin (containing benzene diluent), hexamethylenetetramine (curing agent); Filler: Barium sulfate powder (2000 mesh), ordinary talc powder.

[0040] Preparation process: According to the traditional process, phenolic resin is mixed with curing agent and filler and then injected into mold. It is cured at 80°C for 24 hours. After demolding, it is polished to obtain traditional crystal billiard balls.

[0041] Comparative Example 2 (No segmented curing process) Raw material preparation: Same as in Example 1.

[0042] Preparation process: Except for the curing process which involves heating to 68°C once and holding for 28 hours, the other steps are the same as in Example 1.

[0043] Comparative Example 3 (Alumina Nanomaterials Without Vapor Phase) Raw material preparation: Same as in Example 1, but without fumed alumina nanomaterials.

[0044] Preparation process: Same as in Example 1.

[0045] Performance testing The performance of the billiard balls in Examples 1-3 and Comparative Examples 1-3 was tested, and the testing standards and methods are as follows: Hazardous substance testing: In accordance with GB / T 39600-2021 "Formaldehyde Emission Limits for Wood-based Panels and Their Products" and GB / T27630-2011 "Guidelines for Air Quality Assessment in Passenger Cars", benzene residue and VOCs emission were tested. Mechanical properties: Tensile strength was tested according to GB / T 1040.2-2006 "Determination of tensile properties of plastics - Part 2: Test conditions for molded and extruded plastics"; Shore D hardness was tested according to GB / T 2411-2008 "Determination of indentation hardness (Shore hardness) of plastics and hard rubber using a hardness tester". Yellowing resistance: According to GB / T 1865-2009 "Artificial weathering and artificial radiation exposure of paints and varnishes", the yellowing index (ΔE) was tested after 1000 hours of aging in an ultraviolet aging test chamber (wavelength 340nm, irradiance 0.68W / m², temperature 60℃). Dimensional stability: The billiard balls were placed in a 70℃ oven for 100 hours and then cooled to room temperature to measure the rate of diameter change. Appearance and performance: The transparency of the sphere was tested using a transmittance meter; the surface roughness Ra was tested using a roughness meter.

[0046] The test results are shown in the table below: Performance indicators Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Benzene residue (mg / kg) Not detected Not detected Not detected 8.6 Not detected Not detected VOCs emission (mg / m³) 0.08 0.07 0.09 1.2 0.08 0.07 Tensile strength (MPa) 38.2 39.5 36.8 25.3 32.1 30.5 Shore D hardness 87 88 86 82 85 84 1000h UV aging yellowing index ΔE 1.2 1.1 1.3 4.8 2.7 3.1 Diameter change rate (%) at 70℃ for 100 hours 0.15 0.12 0.18 0.52 0.35 0.38 transparency(%) 92 93 91 85 90 89 Surface roughness Ra (μm) 0.008 0.007 0.009 0.025 0.010 0.011 Results Analysis Comparison of Examples with Comparative Example 1: No benzene residue was detected in Examples 1-3, and the VOCs release was only 0.07-0.09 mg / m³, far lower than 1.2 mg / m³ in Comparative Example 1. This fully demonstrates that the present invention uses an epoxy resin system to fundamentally solve the problem of harmful component residues in traditional billiard balls. At the same time, the tensile strength, transparency, and other properties of the Examples are better than those of Comparative Example 1, indicating that the environmental improvement did not sacrifice the performance of the product, but instead achieved performance enhancement.

[0047] Comparison of Example 1 and Comparative Example 2: Comparative Example 2 did not use the segmented curing process, resulting in a 16% decrease in tensile strength (32.1 MPa) compared to Example 1 (38.2 MPa). The yellowing index (2.7) and diameter change rate (0.35%) were both higher than those of Example 1. This proves that the segmented temperature-curing process can effectively increase the resin crosslinking density and improve the mechanical properties, yellowing resistance and dimensional stability of the product. It is the key process innovation of this invention.

[0048] Comparison of Example 1 and Comparative Example 3: Comparative Example 3 did not add fumed alumina nanomaterials. Its tensile strength (30.5 MPa) was 20.2% lower than that of Example 1. Its yellowing index (3.1) and diameter change rate (0.38%) were also significantly worse than those of Example 1. This shows that the addition of fumed alumina nanomaterials can not only enhance the mechanical properties of the spheres, but also synergistically improve the resistance to yellowing and dimensional stability, producing unexpected technical effects.

[0049] Comparison between examples: Examples 1-3 all produced high-performance environmentally friendly crystal billiard balls by adjusting the raw material ratio and process parameters. Among them, Example 2, due to the optimization of the filler ratio and curing temperature, showed the best performance in terms of tensile strength (39.5MPa), yellowing resistance (ΔE=1.1), and dimensional stability (diameter change rate 0.12%). This proves that the process parameters of the present invention have flexible adjustment space and can optimize product performance according to actual needs.

[0050] The above description of the embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An environmentally friendly crystal billiard ball based on epoxy resin, characterized in that, It consists of a spherical core and an outer coating layer. The preparation steps include raw material pretreatment, spherical core molding, secondary casting and coating, curing, post-processing and surface treatment in sequence. The raw material pretreatment includes the preparation of the substrate system, the treatment of the filler, and the preparation of the mixed slurry. The substrate system uses epoxy resin as the matrix resin and is combined with an amino-based curing agent. The mass ratio of epoxy resin to curing agent is 100:25-30. The filler includes 2800-3500 mesh barium sulfate powder, nano-sized inorganic filler, and high-mesh silica powder with a mesh size ≥20000 mesh. The mixed slurry is divided into a core slurry and a coating layer slurry, both of which are stirred and dispersed by a high-speed disperser. The curing process adopts a segmented heating and curing process, which consists of raising the temperature from room temperature to 45°C and holding it for 10 hours, raising the temperature to 65-70°C and holding it for 18-24 hours, and then naturally cooling to room temperature with a cooling rate of ≤5°C / h. The post-processing and surface treatment include roughing, multi-stage grinding and polishing, and surface cleaning. After treatment, the sphere is free of benzene-related harmful substances, with VOCs emission ≤0.1mg / m³, tensile strength ≥35MPa, and surface roughness Ra≤0.01μm.

2. The environmentally friendly crystal billiard ball based on epoxy resin according to claim 1, characterized in that, The nanoscale inorganic filler is fumed alumina nanomaterials and / or fumed silica, wherein the particle size of the fumed alumina nanomaterials is 20-50 nm, and the specific surface area of ​​the fumed silica is ≥200 m² / g.

3. The environmentally friendly crystal billiard ball based on epoxy resin according to claim 1, characterized in that, The epoxy resin is bisphenol A epoxy resin with an epoxy value of 0.51-0.54 eq / 100g and a viscosity (25℃) of 8000-12000 mPa·s. The amino-based curing agent is diaminodicycloethylmethane.

4. The environmentally friendly crystal billiard ball based on epoxy resin according to claim 1, characterized in that, The core slurry is made by mixing 60%-70% epoxy resin, 15%-18% curing agent, 12%-20% barium sulfate powder and 2%-5% fumed alumina nanomaterials. The coating layer slurry is made by mixing 65%-75% epoxy resin, 16%-19% curing agent, 8%-15% high-mesh silica powder and 1%-3% fumed silica.

5. The environmentally friendly crystal billiard ball based on epoxy resin according to claim 1, characterized in that, After the sphere core is formed, it is ground to a round shape, and the diameter of the sphere core is controlled to be 28-30mm with a roundness error of ≤0.02mm. During the secondary casting and covering, the sphere core is fixed in the center of the mold, and the distance between the sphere core and the inner wall of the mold is 3-4mm.

6. The environmentally friendly crystal billiard ball based on epoxy resin according to claim 1, characterized in that, The filler treatment includes drying barium sulfate powder, nano-sized inorganic filler and high-mesh silicon powder at 120°C for 2-6 hours to remove moisture before using them to prepare a mixed slurry.

7. The environmentally friendly crystal billiard ball based on epoxy resin according to claim 1, characterized in that, The environmentally friendly crystal billiard ball has a diameter of 38.6-38.8mm, a roundness error of ≤0.03mm, a Shore D hardness of ≥85, a yellowing index of ≤1.5 after 1000 hours of ultraviolet aging test, and a transparency of ≥90%.

8. The environmentally friendly crystal billiard ball based on epoxy resin according to claim 1, characterized in that, The post-processing and surface treatment also include an optional laser engraving step, with a laser engraving depth of 0.1-0.2 mm, followed by surface cleaning to remove impurities.