PP ball core material, PVC valve body material and ball valve

Abstract

This invention discloses a PP ball core material, a PVC valve body material, and a ball valve. The PP ball core material comprises the following raw materials in parts by weight: copolymer polypropylene: 80-120 parts, filler: 18-25 parts, hollow glass microspheres: 6-10 parts, nucleating agent: 0.2-0.5 parts, heat stabilizer: 0.4-0.8 parts, antioxidant: 0.2-0.5 parts, and lubricant: 0.3-0.6 parts. When this PP ball core material is used in a ball valve, the resulting PP ball core does not melt, does not stick, and does not collapse at the bottom, exhibiting high roundness, ensuring smooth rotation of the finished ball valve without jamming, seizing, or torque stagnation.

Description

Technical Field

[0001] This invention belongs to the field of plastic ball valve molding and processing technology, and specifically relates to PP ball core material, PVC valve body material and ball valve. Background Technology

[0002] PVC integrated injection molded ball valves are economical valves widely used in water supply, drainage, HVAC, and chemical pipelines. The conventional manufacturing process involves first injection molding a PP ball core, then placing the PP ball core as an insert into the valve body mold, followed by a second PVC injection molding process to form a one-piece ball valve.

[0003] This process has the following insurmountable drawbacks in actual production: 1. The conventional PVC injection molding temperature is 175℃-195℃, which is close to or exceeds the softening temperature of ordinary PP. The bottom of the PP ball core is in direct contact with the high temperature PVC melt, resulting in local melting, sticking, surface collapse, and dimensional distortion. 2. PP is a crystalline plastic. During the secondary heating process, secondary crystallization and secondary shrinkage occur, resulting in poor roundness and excessive ovality of the ball core, and loss of control over the clearance between the ball core and the valve seat. 3. When the ball core deforms, it interferes with the valve body sealing surface and seizes up, resulting in stuck rotation, poor feel, high torque, or even complete inability to turn, directly causing the product to be scrapped.

[0004] Existing technologies mostly use ordinary PP and ordinary PVC, and only improve the situation by reducing the barrel temperature and extending the cooling time. They cannot fundamentally solve the problem in terms of material heat resistance, material compatibility, and shrinkage control. Summary of the Invention

[0005] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a PP ball core material, a PVC valve body material, and a ball valve. When the PP ball core material is used in the ball valve, the bottom of the prepared PP ball core does not melt, does not stick, does not collapse, and has high roundness, ensuring that the finished ball valve rotates smoothly without jamming, seizing, or locking, and has stable torque.

[0006] The above-mentioned technical objective of the present invention is achieved through the following technical solution: PP core material comprises the following raw materials in parts by weight: copolymer polypropylene: 80-120 parts, filler: 18-25 parts, hollow glass microspheres: 6-10 parts, nucleating agent: 0.2-0.5 parts, heat stabilizer: 0.4-0.8 parts, antioxidant: 0.2-0.5 parts, lubricant: 0.3-0.6 parts.

[0007] In some embodiments of the present invention, the filler is obtained by compounding talc powder and wollastonite in a weight ratio of (1.2-1.5):1.

[0008] In some embodiments of the present invention, the hollow glass microspheres are obtained after surface hydrophobic modification.

[0009] In some embodiments of the present invention, the method for hydrophobic modification of the surface of the hollow glass microspheres is as follows: the hollow glass microspheres are dried, stirred and heated to 60–70°C, then a silane coupling agent is added while stirring, the temperature is raised to 70–85°C and kept at that temperature while stirring, and the material is discharged after cooling to obtain surface hydrophobic modified hollow glass microspheres.

[0010] In some embodiments of the present invention, the silane coupling agent is at least one of KH-550 and KH-570.

[0011] In some embodiments of the present invention, the amount of the silane coupling agent added is 0.8%–1.2% of the mass of the hollow glass microspheres.

[0012] In some embodiments of the present invention, the nucleating agent is an α-crystal nucleating agent.

[0013] In some embodiments of the present invention, the nucleating agent is ADK STAB NA-11.

[0014] In some embodiments of the present invention, the heat stabilizer is ADK STAB PEP-36.

[0015] In some embodiments of the present invention, the antioxidant is obtained by compounding antioxidant 1010 and antioxidant 168 in a weight ratio of (0.1-0.3):(0.1-0.2).

[0016] In some embodiments of the present invention, the lubricant is polyethylene wax.

[0017] In some embodiments of the present invention, the heat distortion temperature of the PP ball core material is ≥125℃ and the molding shrinkage rate is ≤0.6%.

[0018] A method for preparing PP core material as described above includes the following steps: mixing the raw materials and then extruding and granulating them to obtain the core material.

[0019] In some embodiments of the present invention, during the mixing process, each raw material is added to a high-speed mixer according to the specified ratio, and mixed at 800-1200 r / min for 5-10 min at a material temperature of 60-80℃.

[0020] In some embodiments of the present invention, the extrusion granulation temperature is 160-185°C.

[0021] In some embodiments of the present invention, the extrusion granulation equipment is a twin-screw extruder, and the temperatures of each zone during extrusion granulation are: Zone 1: 160-170℃; Zone 2: 170-180℃; Zone 3: 180-185℃; Zone 4: 180-185℃; Die head: 178-185℃; and the main extruder speed during extrusion granulation is 280-380 r / min.

[0022] The PVC valve body material comprises the following raw materials in parts by weight: PVC resin: 90-130 parts, plasticizer: 3-8 parts, heat stabilizer: 1.5-2.5 parts, lubricant: 0.6-1.2 parts, filler: 5-15 parts, modifier: 2.8-5.5 parts.

[0023] In some embodiments of the present invention, the plasticizer is dioctyl terephthalate.

[0024] In some embodiments of the present invention, the heat stabilizer is an organotin heat stabilizer.

[0025] In some embodiments of the present invention, the heat stabilizer is thiol methyltin heat stabilizer TM-181.

[0026] In some embodiments of the present invention, the lubricant is a compound lubricant of PE wax and stearic acid.

[0027] In some embodiments of the present invention, the filler is calcium carbonate.

[0028] In some embodiments of the present invention, the modifier is obtained by compounding modifier ACR and modifier CPE in a weight ratio of (0.8-1.5):(2-4).

[0029] A method for preparing PVC valve body material as described above includes the following steps: mixing the raw materials and then mixing or extruding and granulating them to obtain the final product.

[0030] In some embodiments of the present invention, the mixing is performed by first mixing at 100-110°C for 8-12 minutes, then cooling to 45°C before discharging.

[0031] In some embodiments of the present invention, the mixing or extrusion granulation temperature is 145-170°C.

[0032] In some embodiments of the present invention, the mixing temperature is 145-165°C.

[0033] In some embodiments of the present invention, the extrusion granulation is carried out by a single-screw or twin-screw granulator, and the temperature of each zone is: Zone 1: 150-155℃; Zone 2: 155-165℃; Zone 3: 160-170℃; Die head: 160-168℃.

[0034] A ball valve comprising a PP ball core and a PVC valve body, wherein the PP ball core is made of the PP ball core material as described above, and the PVC valve body is made of the PVC valve body material as described above.

[0035] A method for manufacturing the ball valve as described above includes the following steps: (1) The PP ball core material is injection molded in a spherical mold and then demolded to obtain the PP ball core; (2) The PP ball core is placed into the valve body mold as an insert, and the PVC valve body material is injection molded in the valve body mold. After demolding, the ball valve is obtained.

[0036] In some embodiments of the present invention, in step (1), the parameters of the injection molding are: barrel temperature 170-185℃, mold temperature 30-50℃, injection pressure 60-90MPa, holding pressure 40-60MPa, holding pressure 10-20s, cooling 20-40s, demolding temperature ≤60℃, and room temperature standing time after molding ≥2h.

[0037] In some embodiments of the present invention, in step (1), the temperature of the injection molding barrel is: rear section of the barrel: 165-175℃, middle section of the barrel: 170-180℃, front section of the barrel: 175-185℃, nozzle: 180-185℃.

[0038] In some embodiments of the present invention, in step (2), the parameters of the injection molding are: barrel temperature 160-180℃, mold temperature 35-50℃, injection pressure 60-90MPa, holding pressure 30-50MPa, holding pressure 6-12s, cooling ≥40s, demolding temperature ≤60℃, and room temperature standing time after molding ≥2h.

[0039] In some embodiments of the present invention, in step (2), the temperature of the injection molding barrel is: rear section of the barrel: 160-165℃, middle section of the barrel: 165-172℃, front section of the barrel: 170-178℃, nozzle: 175-180℃.

[0040] In some embodiments of the present invention, in step (2), the valve body mold is provided with an independent circulating cooling structure in the bottom area of ​​the ball core, so that the temperature of the bottom area of ​​the ball core is ≤30°C during the injection molding process.

[0041] The beneficial effects of this invention are: (1) When the PP ball core material of the present invention is used in the ball valve, the bottom of the prepared PP ball core does not melt, does not stick, does not collapse, and has high roundness, ensuring that the finished ball valve rotates smoothly, without jamming, without seizing, and with stable torque. (2) The PP ball core material of the present invention is controlled by adding specific fillers and nucleating agents, combined with mold cooling during the ball valve preparation process, room temperature static cooling treatment after mold opening, so that the secondary shrinkage of the PP ball core is controllable and the roundness is stable. (3) The present invention provides a heat-resistant, low-shrinkage PP ball core with a low-temperature, low-melting-point PVC valve body, which reduces heat damage from the source of materials; (4) The present invention adopts forced cooling at the bottom of the ball core, low-temperature PVC injection molding, and multi-stage pressure holding cooling, so as to achieve non-melting, non-sticking, and non-deformation of PP ball core without changing the structure; (5) The ball valve of the present invention does not require modification of mold or structural change, and can be mass-produced directly on existing equipment. Detailed Implementation

[0042] The present invention will be further described below with reference to specific embodiments.

[0043] Example 1: The PP core material comprises the following raw materials in parts by weight: copolymer polypropylene: 100 parts, filler: 22 parts, hollow glass microspheres: 8 parts, α-crystal nucleating agent: 0.3 parts, heat stabilizer: 0.6 parts, antioxidant: 0.3 parts, and polyethylene wax: 0.4 parts. The filler is obtained by compounding talc and wollastonite in a weight ratio of 1.3:1. The α-crystal nucleating agent is ADK STAB NA-11, the heat stabilizer is ADK STAB PEP-36, and the antioxidant is obtained by compounding antioxidant 1010 and antioxidant 168 in a weight ratio of 0.1:0.2.

[0044] Hollow glass microspheres are obtained by surface hydrophobic modification. The specific hydrophobic modification steps are as follows: (1) Drying: Dry the hollow glass microspheres at 115℃ for 1.5h to remove surface moisture; (2) High-speed stirring: Add hollow glass microspheres to a high-speed mixer, rotate at 900 rpm, and stir to heat to 65°C; (3) Spray modification: Slowly spray in silane coupling agent KH-550, the amount of silane coupling agent being 1.0% of the mass of the hollow glass microspheres; (4) Insulation and coating: Continue stirring for 10 minutes, keep the temperature at 80℃, so that the coupling agent is evenly coated; (5) Cooling and discharging: Cool to below 40℃ and discharge to obtain surface hydrophobic modified hollow glass microspheres.

[0045] The heat distortion temperature of the PP ball core material is 130℃, and the molding shrinkage rate is 0.5%.

[0046] A method for preparing PP core material as described above includes the following steps: adding each raw material to a high-speed mixer according to the ratio, mixing at 1000 r / min for 8 min, and after the material temperature is 70℃, extruding and granulating through a twin-screw extruder to obtain the granulated material. The temperatures of each zone during extrusion granulation are: Zone 1: 165℃; Zone 2: 175℃; Zone 3: 185℃; Zone 4: 185℃; Die head: 180℃; the main extruder speed during extrusion granulation is 300 r / min.

[0047] The PVC valve body material comprises the following raw materials in parts by weight: PVC resin: 100 parts, plasticizer: 5 parts, organotin heat stabilizer: 2 parts, lubricant: 1 part, calcium carbonate: 10 parts, and modifier: 4 parts. The plasticizer is dioctyl terephthalate, the organotin heat stabilizer is methyl tin mercaptan heat stabilizer TM-181, the lubricant is a mixture of PE wax and stearic acid in a weight ratio of 1:1, and the modifier is a mixture of modifier ACR and modifier CPE in a weight ratio of 1:3.

[0048] A method for preparing PVC valve body material as described above includes the following steps: mixing the raw materials at 100°C for 10 minutes, cooling to 45°C and then discharging the mixture, followed by extrusion granulation using a single-screw extruder. The temperatures of each zone during extrusion granulation are: Zone 1: 150°C; Zone 2: 160°C; Zone 3: 165°C; Die head: 165°C; The main extruder speed during extrusion granulation is 300 r / min.

[0049] A ball valve includes a PP ball core and a PVC valve body, wherein the PP ball core is made of the PP ball core material as described above, and the PVC valve body is made of the PVC valve body material as described above.

[0050] A method for manufacturing the ball valve as described above includes the following steps: (1) After injection molding the PP ball core material in a spherical mold, the PP ball core is obtained by demolding. The injection molding parameters are: rear section of the barrel: 165℃, middle section of the barrel: 170℃, front section of the barrel: 175℃, nozzle: 180℃, mold temperature: 40℃, injection pressure: 70MPa, holding pressure: 50MPa, holding pressure: 15s, cooling: 45s, demolding temperature: 50℃, and room temperature standing time after molding: 2h. (2) The PP ball core is placed into the valve body mold as an insert, and the PVC valve body material is injection molded in the valve body mold. After demolding, the ball valve is obtained. The injection molding parameters are: rear section of the barrel: 160℃, middle section of the barrel: 165℃, front section of the barrel: 170℃, nozzle: 175℃, mold temperature 40℃, injection pressure 70MPa, holding pressure 40MPa, holding pressure 10s, total cooling time 45s, demolding temperature 50℃, and room temperature standing time after molding 2h, so that the PP ball core and PVC valve body shrink synchronously and the internal stress is fully released. The valve body mold is equipped with an independent circulating cooling structure in the bottom area of ​​the ball core, so that the temperature in the bottom area of ​​the ball core is ≤30℃ during the injection molding process.

[0051] The resulting ball core is free from melting and deformation, with a roundness of ≤0.03mm, and the ball valve rotates smoothly without jamming.

[0052] Example 2: The PP core material comprises the following raw materials in parts by weight: copolymer polypropylene: 80 parts, filler: 18 parts, hollow glass microspheres: 6 parts, α-crystal nucleating agent: 0.2 parts, heat stabilizer: 0.4 parts, antioxidant: 0.2 parts, and polyethylene wax: 0.2 parts. The filler is obtained by compounding talc and wollastonite in a weight ratio of 1.2:1. The α-crystal nucleating agent is ADK STAB NA-11, the heat stabilizer is ADK STAB PEP-36, and the antioxidant is obtained by compounding antioxidant 1010 and antioxidant 168 in a weight ratio of 0.1:0.1. The hollow glass microspheres are obtained after surface hydrophobic modification, and the surface hydrophobic modification method is the same as in Example 1.

[0053] The heat distortion temperature of the PP ball core material is 125℃, and the molding shrinkage rate is 0.6%.

[0054] A method for preparing PP core material as described above includes the following steps: adding each raw material to a high-speed mixer according to the ratio, mixing at 800 r / min for 10 min, and after the material temperature reaches 60℃, granulating it by extrusion through a twin-screw extruder. The temperatures of each zone during extrusion granulation are: Zone 1: 160℃; Zone 2: 170℃; Zone 3: 180℃; Zone 4: 180℃; Die head: 178℃; The main extruder speed during extrusion granulation is 280 r / min.

[0055] The PVC valve body material comprises the following raw materials in parts by weight: PVC resin: 90 parts, plasticizer: 3 parts, organotin heat stabilizer: 1.5 parts, lubricant: 0.6 parts, calcium carbonate: 5 parts, modifier: 2.8 parts. The plasticizer is dioctyl terephthalate, the organotin heat stabilizer is methyl tin mercaptan heat stabilizer TM-181, the lubricant is a mixture of PE wax and stearic acid in a 1:1 weight ratio, and the modifier is a mixture of modifier ACR and modifier CPE in a 0.8:2 weight ratio.

[0056] A method for preparing PVC valve body material as described above includes the following steps: mixing the raw materials at 100°C for 12 minutes, cooling to 45°C and then discharging the mixture, followed by extrusion granulation using a single-screw extruder. The temperatures of each zone during extrusion granulation are: Zone 1: 152°C; Zone 2: 155°C; Zone 3: 160°C; Die head: 160°C; The main extruder speed during extrusion granulation is 300 r / min.

[0057] A ball valve includes a PP ball core and a PVC valve body. The PP ball core is made of the PP ball core material as described above, and the PVC valve body is made of the PVC valve body material as described above.

[0058] A method for manufacturing the ball valve as described above includes the following steps: (1) After injection molding the PP ball core material in a spherical mold, the PP ball core is obtained by demolding. The injection molding parameters are: rear section of the barrel: 170℃, middle section of the barrel: 175℃, front section of the barrel: 180℃, nozzle: 182℃, mold temperature: 35℃, injection pressure: 60MPa, holding pressure: 30MPa, holding pressure: 12s, cooling: 40s, demolding temperature: 50℃, and room temperature standing time after molding: 2h. (2) The PP ball core is placed into the valve body mold as an insert, and the PVC valve body material is injected into the valve body mold. After demolding, the ball valve is obtained. The injection molding parameters are: rear section of the barrel: 165℃, middle section of the barrel: 172℃, front section of the barrel: 178℃, nozzle: 180℃, mold temperature 40℃, injection pressure 70MPa, holding pressure 40MPa, holding pressure 10s, total cooling time 45s, demolding temperature 50℃, and room temperature standing time after molding 2h, so that the PP ball core and PVC valve body shrink synchronously and the internal stress is fully released. The valve body mold is equipped with an independent circulating cooling structure in the bottom area of ​​the ball core, so that the temperature in the bottom area of ​​the ball core is ≤30℃ during the injection molding process.

[0059] The resulting ball core is free from melting and deformation, with a roundness of ≤0.03mm, and the ball valve rotates smoothly without jamming.

[0060] Example 3: The PP core material comprises the following raw materials in parts by weight: copolymer polypropylene: 120 parts, filler: 25 parts, hollow glass microspheres: 10 parts, α-crystal nucleating agent: 0.5 parts, heat stabilizer: 0.8 parts, antioxidant: 0.5 parts, and polyethylene wax: 0.6 parts. The filler is obtained by compounding talc and wollastonite in a weight ratio of 1.5:1. The α-crystal nucleating agent is ADK STAB NA-11, the heat stabilizer is ADK STAB PEP-36, and the antioxidant is obtained by compounding antioxidant 1010 and antioxidant 168 in a weight ratio of 0.3:0.2. The hollow glass microspheres are obtained after surface hydrophobic modification, and the surface hydrophobic modification method is the same as in Example 1.

[0061] The heat distortion temperature of the PP ball core material is 135℃, and the molding shrinkage rate is 0.55%.

[0062] A method for preparing PP core material as described above includes the following steps: adding each raw material to a high-speed mixer according to the ratio, mixing at 1000 r / min for 8 min, and after the material temperature is 70℃, extruding and granulating through a twin-screw extruder to obtain the granulated material. The temperatures of each zone during extrusion granulation are: Zone 1: 165℃; Zone 2: 175℃; Zone 3: 185℃; Zone 4: 185℃; Die head: 180℃; the main extruder speed during extrusion granulation is 300 r / min.

[0063] The PVC valve body material comprises the following raw materials in parts by weight: PVC resin: 130 parts, plasticizer: 8 parts, organotin heat stabilizer: 2.5 parts, lubricant: 1.2 parts, calcium carbonate: 15 parts, and modifier: 5.5 parts. The plasticizer is dioctyl terephthalate, the organotin heat stabilizer is methyl tin mercaptan heat stabilizer TM-181, the lubricant is a mixture of PE wax and stearic acid in a 1:1 weight ratio, and the modifier is a mixture of modifier ACR and modifier CPE in a 1.5:4 weight ratio.

[0064] A method for preparing PVC valve body material as described above includes the following steps: mixing the raw materials at 100°C for 10 minutes, cooling to 45°C and then discharging the mixture, followed by extrusion granulation using a single-screw extruder. The temperatures of each zone during extrusion granulation are: Zone 1: 150°C; Zone 2: 160°C; Zone 3: 165°C; Die head: 165°C; The main extruder speed during extrusion granulation is 300 r / min.

[0065] A ball valve includes a PP ball core and a PVC valve body. The PP ball core is made of the PP ball core material as described above, and the PVC valve body is made of the PVC valve body material as described above.

[0066] A method for manufacturing the ball valve as described above includes the following steps: (1) After injection molding the PP ball core material in a spherical mold, the PP ball core is obtained by demolding. The injection molding parameters are: rear section of the barrel: 165℃, middle section of the barrel: 170℃, front section of the barrel: 175℃, nozzle: 180℃, mold temperature: 40℃, injection pressure: 70MPa, holding pressure: 50MPa, holding pressure: 15s, cooling: 45s, demolding temperature: 50℃, and room temperature standing time after molding: 2h. (2) The PP ball core is placed into the valve body mold as an insert, and the PVC valve body material is injection molded in the valve body mold. After demolding, the ball valve is obtained. The injection molding parameters are: rear section of the barrel: 160℃, middle section of the barrel: 165℃, front section of the barrel: 170℃, nozzle: 175℃, mold temperature 40℃, injection pressure 70MPa, holding pressure 40MPa, holding pressure 10s, total cooling time 45s, demolding temperature 50℃, and room temperature standing time after molding 2h, so that the PP ball core and PVC valve body shrink synchronously and the internal stress is fully released. The valve body mold is equipped with an independent circulating cooling structure in the bottom area of ​​the ball core, so that the temperature in the bottom area of ​​the ball core is ≤30℃ during the injection molding process.

[0067] The resulting ball core is free from melting and deformation, with a roundness of ≤0.03mm, and the ball valve rotates smoothly without jamming.

[0068] Comparative Example 1: A ball valve includes a PP ball core and a PVC valve body, wherein the PP ball core is made of commercially available ordinary PP material and the PVC valve body is made of commercially available ordinary PVC material.

[0069] A method for preparing the ball valve as described above is exactly the same as the method for preparing the ball valve in Example 1.

[0070] The bottom of the resulting sphere core was clearly melted, shrank significantly, and had poor roundness; the finished product was stuck and could not be twisted.

[0071] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. PP spherical core material, characterized in that: The raw materials include the following parts by weight: Copolymer polypropylene: 80-120 parts, filler: 18-25 parts, hollow glass microspheres: 6-10 parts, nucleating agent: 0.2-0.5 parts, heat stabilizer: 0.4-0.8 parts, antioxidant: 0.2-0.5 parts, lubricant: 0.3-0.6 parts.

2. The PP core material according to claim 1, characterized in that: The filler is prepared by compounding talc powder and wollastonite in a weight ratio of (1.2-1.5):

1.

3. The PP core material according to claim 1, characterized in that: The nucleating agent is an α-crystal nucleating agent.

4. The PP core material according to claim 1, characterized in that: The PP core material has a heat distortion temperature ≥125℃ and a molding shrinkage rate ≤0.6%.

5. A method for preparing the PP core material as described in any one of claims 1 to 4, characterized in that: Includes the following steps: The raw materials are mixed and then extruded into granules to obtain the final product.

6. PVC valve body material, characterized in that: The raw materials include the following parts by weight: PVC resin: 90-130 parts, plasticizer: 3-8 parts, heat stabilizer: 1.5-2.5 parts, lubricant: 0.6-1.2 parts, filler: 5-15 parts, modifier: 2.8-5.5 parts.

7. A ball valve, characterized in that: The ball valve includes a PP ball core and a PVC valve body. The PP ball core is made from the PP ball core material as described in any one of claims 1-4, and the PVC valve body is made from the PVC valve body material as described in claim 6.

8. A method for preparing the ball valve as described in claim 7, characterized in that: Includes the following steps: (1) The PP ball core material is injection molded in a spherical mold and then demolded to obtain the PP ball core; (2) The PP ball core is placed into the valve body mold as an insert, and the PVC valve body material is injection molded in the valve body mold. After demolding, the ball valve is obtained.

9. The method for preparing the ball valve according to claim 8, characterized in that: In step (1), the parameters for injection molding are: barrel temperature 170-185℃, mold temperature 30-50℃, injection pressure 60-90MPa, holding pressure 40-60MPa, holding pressure 10-20s, cooling 20-40s, demolding temperature ≤60℃, and room temperature standing time after molding ≥2h.

10. The method for preparing the ball valve according to claim 8, characterized in that: In step (2), the parameters for injection molding are: barrel temperature 160-180℃, mold temperature 35-50℃, injection pressure 60-90MPa, holding pressure 30-50MPa, holding pressure 6-12s, cooling ≥40s, demolding temperature ≤60℃, and room temperature standing time after molding ≥2h.