TH14599A - How to print flat containers with thick walls? It's highly variable, mainly through blow molding. - Google Patents

Abstract

Flat containers can be produced by extruding molten resin into a bulb shape, sealing the bottom of the bulb, blowing the bulb in a way that prevents the inner surfaces from contacting each other, dragging the bulb while in a molten state, expanding the bulb so that the outer edge protrudes beyond the mold cavity, squeezing the expanded bulb with the mold to fuse the molten edges together along the outer edge of the cavity, and forcing the pressurized fluid into the bulb so that it forms a tight seal with the inner surface of the mold cavity. This method can facilitate the production of highly flat containers in a simple process.

Claims (5)

1. The procedure for producing containers by blow molding from molten resin is as follows: - Extruding molten resin from the mold head (1) into a bulb shape (2); - Sealing the bottom of the bulb (2) by squeezing; - Pre-shaping a portion of the bulb (2) into a thick-walled section (10) by applying fluid pressure into the bulb (2) at a pressure sufficient to prevent contact between the inner surfaces of the bulb (2); - Pulling the remaining portion of the bulb (2) lengthwise at a ratio of at least 1.1 times its original length (Io) while the bulb (2) is at a temperature no lower than the resin melting point; - Defining the bulb (2) in a separate mold (7) with a mill (76) in the same shape as the container; and - Forcing pressurized fluid into the bulb (2) that is defining it in the mold (7), so that the bulb (2) will It is pushed to make firm contact with the inner surface of the mold cavity. In this manner, before the bulb (2) is confined to the separate mold (7), the bulb is expanded to a thin wall using a sharpener under pressure to create a pressure difference across the wall of the bulb (2). The bulb (2) is expanded so that the front surface of the bulb (2) spreads beyond the side edges of the mold cavity, while the cavity (7) is pressed in to form the sides of the bulb (2) to fuse them together. 2. The process under claim 1 where the ratio of the wall thickness of the thick section of the printed container to the wall thickness of the thin section is at least 5 to 1. 3. The process under claim 1 or 2 where the ratio of the diameter of the larger to the diameter of the mold cavity is at least 2.5 to 1. 4. The process according to claims 1, 2 or 3 where such resin is polypropylene, polyethylene or poly(4-methyl-1-pentene). 5. The procedure under any of the above claims where such procedure of the formation of the wall thickness section (10) consists of the procedure of limiting the upper part of the bulb (2) between the two sections of the first section mold (Clause 5, page 2, figure 4).