JPS5933093B2 - resin bubble stabilizer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a resin bubble stabilizer that is used by standing up on the top surface of an annular die when extruding a blown film.

Conventionally, a cylindrical resin bubble stabilizer was erected on the top surface of an annular die, and the synthetic resin tubular body melted and extruded upward from the annular die was raised along the outer circumferential surface of the resin bubble stabilizer while being air-cooled. There is a known method of extrusion molding a blown film by rapidly expanding the resin bubble with pressurized air to form a resin bubble, flattening the resin bubble with nip rolls and taking it off.

This method has a high expansion ratio of the resin bubbles and a high take-up speed of the blown film, so it has a good balance of mechanical strength in the vertical and horizontal directions and has excellent impact strength. It has the advantage that a flasion film can be formed. However, the shape of the synthetic resin tubular body melt-extruded from the annular die changes when the molding conditions of the blown film, especially the expansion ratio and take-up speed, change. If the resin bubble stabilizer is not replaced in accordance with The disadvantage was that the mechanical strength of the film was reduced. That is, when the melt-extruded synthetic resin tubular body comes into contact with the outer peripheral surface of the resin bubble stabilizer, numerous scratches occur on the inner surface of the synthetic resin tubular body, reducing the mechanical strength of the resulting blown film. If the synthetic resin tubular body is too far away from the outer circumferential surface of the resin bubble stabilizer, the resin bubbles will tend to sway, resulting in uneven cooling and uneven thickness and wrinkles in the resulting blown film, which will also reduce the yield. This is because the mechanical strength of the blown film decreases.
Here, the present inventors conducted various studies on resin bubble stabilizers whose outer peripheral surface shape can be changed, and as a result, they discovered the present invention.

That is, the present invention provides a cylindrical resin bubble stabilizer having an outer peripheral surface with an open top and a circular cross section, which is installed upright on the upper surface of an annular die, and whose base has an outer diameter much smaller than the inner diameter of the die lip. A resin bubble characterized in that a hole communicating with the upper end opening is provided in the peripheral wall of the base, and the outer peripheral surface of the resin bubble stabilizer located above the hole is formed by stacking a large number of annular members in a detachable manner. This relates to a stabilizer, and by replacing the annular member, the outer peripheral surface of the resin bubble stabilizer can be easily changed into various shapes depending on the extrusion molding conditions of the blown film. . Next, the present invention will be explained in more detail with reference to the drawings.

In FIGS. 1 to 3, the resin bubble stabilizer 1 consists of a support 2, an annular member 3, and a fixing nut 6. As shown in FIGS. The support 2 that is installed coaxially with the annular die 9 is connected to the die lip 10.
It is an elongated cylindrical body with an outer diameter smaller than the inner diameter of the column and an opening 5 at the upper end, and has a hole 4 in the peripheral wall of its base, and a male thread is cut on the outer peripheral surface of the support column 2. Nine annular members 3 are fitted onto the pillar 2 in a stacked manner, and are fixed above the hole 4 of the pillar 2 with a fixing nut 6. Here, the number of holes provided in the base peripheral wall is not particularly limited, but it is preferable to provide a plurality of holes. FIG. 1 shows a resin bubble stabilizer 1 formed by stacking annular members 3 to form a tapered right circular truncated cone whose lower end is equal to the outer diameter of the die lip 10 and whose diameter decreases upward. Such a resin bubble stabilizer 1 is
This is extremely effective when the blown film is taken at a high speed. That is, when the take-up speed of the blown film is high, the synthetic resin tubular body 7 melted and extruded from the annular die 9 tends to be pulled up in a cylindrical shape with a diameter reduced upward, so that the resin bubble is stabilized. If the shape of the outer circumferential surface of the body 1 is also tapered upward, the synthetic resin annular body 7 will come into contact with the outer circumferential surface of the resin bubble stabilizer 1 while being cooled by the cooling air blown out from the air cooling ring. This is because the synthetic resin tubular body 7 can be cooled uniformly without causing the resin bubble 8 to sway. In FIG. 2, the annular member 3 is replaced and the outer peripheral surface of the resin bubble stabilizer 1 is made into a tapered shape that expands upward.
A resin bubble stabilizer 1 is shown which is effective when the take-up speed of the blown film is slow. Figure 3 A: Similarly, the mouth is made of a cylindrical annular member on the outer peripheral surface of the resin bubble stabilizer 1.
3 is formed by stacking annular members 3 into a direct truncated cone shape and a stacked part of the annular member 3. The resin bubble stabilizer 1 shown in FIG. 1 to FIG.
As shown in the figure, there is an advantage that the outer peripheral surface can be divided into two parts. FIG. 4 shows a structure in which a male thread 12 and a female thread 13 are provided at the upper and lower ends of each annular member 3, respectively, and the annular members 3 are connected to each other. The resin bubble stabilizer 1 is shown with the struts 2 attached. In the resin bubble stabilizer 1 of the present invention, the shape of the outer peripheral surface can be changed by replacing the annular member 3, and a hole 4 communicating with the upper end opening 5 is provided in the peripheral wall of the base. The extruded synthetic resin tubular body 7 does not come into contact with the outer peripheral surface of the resin bubble stabilizer 1. That is, when extruding a blown film, if the shape of the outer peripheral surface of the resin bubble stabilizer 1 is adjusted in advance according to the shape of the melt-extruded synthetic resin tubular body 7, the shape of the melt-extruded synthetic resin tubular body 7 can be adjusted in advance. 7 rises along the outer circumferential surface of the resin bubble stabilizer 1, a kind of suction effect is created inside and outside the hole 4 provided at the base of the resin bubble stabilizer 1, causing this to flow from the inside of the resin bubble stabilizer 1 to the outside. Pressurized air flows out through the hole 4, and the flowed out pressurized air is accompanied by the rising synthetic resin tubular body 7, forming an upward flow along the outer peripheral surface of the resin bubble stabilizer 1, and this upward flow This is because it prevents the synthetic resin tubular body 7 from coming into contact with the outer peripheral surface of the resin bubble stabilizer 1. As means for fixing the annular member 3 of the resin bubble stabilizer 1 in the present invention, ordinary fixing means can be used in addition to those shown in the drawings.
The annular member of the resin bubble stabilizer in the present invention is generally made of aluminum metal and has a cylindrical or truncated conical outer peripheral surface.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of a blown film extrusion molding apparatus in which the resin bubble stabilizer of the present invention is arranged;
3 and 3 are cross-sectional views of a resin bubble stabilizer of the present invention having another outer peripheral surface shape, and FIG. 4 is a cross-sectional view of a resin bubble stabilizer having another ring member fixing means. DESCRIPTION OF SYMBOLS 1... Resin bubble stabilizer, 2... Pillar of bubble stabilizer, 3... Annular member forming the outer peripheral surface of resin bubble stabilizer, 4... ... Hole provided in the peripheral wall of the base of the column, 5... Opening at the top end of the column, 6...
...Fixing nut for fixing the annular member to the column, 7.
...Synthetic resin tubular body melt-extruded from an annular die,
8... Resin bubble, 9... Annular die,
10...Die lip, 11...Air cooling ring, 12...Male thread provided at the upper end of the annular member, 13...Female thread provided at the lower end of the annular member .

Claims (1)

[Claims] 1. In a cylindrical resin bubble stabilizer having an outer circumferential surface with an open top and a circular cross section, which stands on the upper surface of an annular die, the base thereof has an outer diameter that is one step smaller than the inner diameter of the die lip, and the circumferential wall of the base has a 1. A resin bubble stabilizer, characterized in that a hole communicating with an upper end opening is provided, and the outer peripheral surface of the resin bubble stabilizer located above the hole is formed by stacking a number of annular members in a detachable manner.