US 12,304,118 B2
Method for processing PVC ball
Shaofeng Shi, Chuzhou (CN)
Assigned to Dongguan Jiaheng Toys Co., Ltd., Dongguan (CN)
Filed by Dongguan Jiaheng Toys Co., Ltd., Dongguan (CN)
Filed on Mar. 24, 2023, as Appl. No. 18/125,804.
Claims priority of application No. 202210350218.4 (CN), filed on Apr. 2, 2022.
Prior Publication US 2023/0311370 A1, Oct. 5, 2023
Int. Cl. B29C 41/04 (2006.01); B29C 41/00 (2006.01); B29C 41/46 (2006.01); B29C 59/02 (2006.01); B29D 22/04 (2006.01); B29K 27/06 (2006.01); B29K 105/00 (2006.01); B29L 31/54 (2006.01)
CPC B29C 41/04 (2013.01) [B29C 41/003 (2013.01); B29C 41/46 (2013.01); B29C 59/02 (2013.01); B29K 2027/06 (2013.01); B29K 2105/0032 (2013.01); B29L 2031/54 (2013.01)] 6 Claims
OG exemplary drawing
 
1. A method for processing a PVC (Polyvinyl Chloride) ball, comprising the following steps:
Step A: carrying out a first ball shaping of a PVC paste located inside a first mold using a roto-cast machine or a rotational molding machine, to produce a hollow PVC ball, wherein in the PVC paste, a PVC resin has a mass percentage of 40%-60%, a plasticizer has a mass percentage of 40%-60%, and an auxiliary agent has a mass percentage of 3%-8%, wherein the first ball shaping comprises the following steps:
Step A1: preparing the PVC paste suitable for roto-cast or rotational molding processes using mixing equipment;
Step A11: sticking a PVC film having a predetermined pattern onto an inner surface of the first mold to accomplish labelling;
Step A2: pouring the prepared PVC paste into the first mold;
Step A3: closing a mold cover and tightening it using a bolt, then placing the first mold into a furnace chamber of the roto-cast machine or the rotational molding machine to heat for heated and plasticized shaping, and stopping heating after a continuous preset heating time S1, so that the PVC paste is shaped on an inner wall of the first mold by way of roto-cast or rotational molding;
Step A4: taking the first mold out of the roto-cast machine or the rotational molding machine and then cooling the first mold; and
Step A5: opening the first mold to obtain the hollow PVC ball;
Step B: charging a gas to an interior of the shaped ball, so that the ball has an external diameter equal to a diameter of an inner cavity of a second mold; and
Step C: placing the gas-charged ball into the second mold, then carrying out a second texture shaping of the shaped gas-charged ball located inside the second mold using the roto-cast machine or the rotational molding machine, to produce a texture on a surface of the shaped PVC ball, wherein the second texture shaping comprises the following steps:
Step C1: placing a gas-charged smooth-surfaced hollow PVC ball into a second mold having a predetermined texture, and closing a mold cover;
Step C2: placing the second mold into the furnace chamber of the roto-cast machine or the rotational molding machine to heat, wherein the internal gas of the PVC ball expands, through the principle of thermal expansion, so that the PVC ball presses against an inner wall of the second mold and the PVC ball forms a texture on the surface through heated and plasticized shaping, then stopping heating after a continuous preset heating time S1;
Step C3: taking the second mold out of the furnace chamber of the roto-cast machine or the rotational molding machine and cooling it; and
Step C4: opening the second mold to obtain a PVC ball having both the predetermined pattern and the predetermined texture.