JPH02261624A - Production equipment of lay-flat extrusion film - Google Patents

Abstract

PURPOSE:To obtain the production equipment of film, the crack on which is prevented from occurring and consequently the product quality of which is improved, by lay-flat extrusion by a structure wherein a hot air cutting-off mechanism formed by annularly installing a plurality of rolling elements, each of which is made of silicone rubber as a whole or the outer peripheral surface of the base material of each of which is lined with silicone rubber. CONSTITUTION:A hot air cutting-off mechanism 10 consists of a plurality of sets, each of which is composed of a fixed shaft 11 and one or a plurality of rolling elements 12 installed at the tip part of the shaft, providing at equal intervals,on an annular supporting frame 6. Each rolling element 12 is spherical or roller-like shape and made of material having large frictional resistance as a whole or of base material 13, the outer peripheral surface of which is lined with material 14 such as shrunk tube of silicone rubber or the like. In the hot air cutting-off mechanism 10 having the above-mentioned structure, expanded bubble 2 is in the state being supported by the peripheral side faces of the respective rolling elements 12, which are annularly installed round the bubble. Since the rolling elements 12 rotate together with the upward movement of film, there in no fear to generate scratches or the like on the surface of the film due to the flaw or deformation on the silicone rubber, which is even developed after long term use.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an apparatus for producing a film by an inflation method, and particularly to an apparatus for producing a film by an inflation method made of a thermoplastic resin such as polyolefin.

(Prior Art) Generally, in the production of film by the inflation method, in order to maintain uniform and stable stretching from the start to the end of stretching, a die (not shown) is used as shown in FIG. ) Thick-walled stalk a extruded from
Hot air of 100 to 200°C is ejected from an annular slit b around the bubble C, which is expanded by the air blown into the bubble C, and a tubular draft shield d provided around it. Therefore, a method is adopted in which the bubble C is kept warm from the outside. For this reason, a mechanism is provided between the upper edge e of the draft shield d and the bubble C to block hot air and improve heat retention efficiency.

(Problem to be solved by the invention) Conventionally, mechanisms for this purpose have been made entirely of Teflon, since it can withstand high temperatures and has low frictional resistance.
Or rod f with Teflon lining on the surface of the base material
, which is partially buried in the upper edge e, has been exclusively used.

However, this Teflon rod f is also softened by heat, and when used for a long time, minute scratches occur on its surface due to wear. The film was still soft near the upper iris, so if this surface came into contact with the fine scratches on the Teflon, a large amount of scratches would occur, reducing the quality of the product.

An object of the present invention is to provide an apparatus for producing a film by the inflation method, which prevents the occurrence of scratches and improves the quality of the product.

(Means for Solving the Problems) The present inventor discovered that although a conventional device used a hot air blocking mechanism with low frictional resistance in the upper iris, it was fixed and caused damage to the film surface. After careful consideration, we found that the blocking mechanism should rotate as the film moves, and that in order to ensure smooth rotation, it would be best to use a material with a high frictional resistance, contrary to the conventional method. It was discovered that silicone rubber was the most suitable for this purpose, and the present invention was completed.

Therefore, the present invention provides a tubular draft shield around the outer periphery of the expanded bubble, blows hot air into the tubular draft shield to keep the bubble warm, and also provides a hot air blocking mechanism between the bubble and the bubble at the upper edge of the draft shield. In the film manufacturing apparatus using the inflation method, a plurality of rolling elements made entirely of silicone rubber or made of a base material whose outer peripheral surface is lined with silicone rubber are disposed in an annular shape as the hot air blocking mechanism. The gist of this document is that

(Example) Hereinafter, specific aspects of the present invention will be explained using examples shown in FIGS. 1 to 4, but the present invention is not limited thereto.

FIG. 1 shows a first embodiment of the blown film production apparatus according to the present invention, in which 1 is a thick stalk extruded from an annular die (not shown), and 2 is expanded by air blown into the inside. The bubble formed, 3 is a tubular draft shield provided surrounding the bubble 2, 4 is a hot air supply port provided at the bottom end of the bubble, 5 is a hot air exhaust port provided at the top thereof, 6 is a support frame provided in an annular shape on its upper edge.

Note that this hot air exhaust port 5 is connected to a frame 8 provided on the upper edge of the draft shield 3 via an elastic material 7 so as to be movable up and down.
This allows the displacement amount to be adjusted as desired by changing the gap with the support frame 6.

IO is a plurality of hot air blocking mechanisms provided at equal intervals on an annular support frame 6, and is composed of a fixed shaft 11 and one or more rolling elements 12 attached to the tip thereof.

This rolling element 12 is spherical or roller-shaped and made entirely of a material with high frictional resistance such as silicone rubber, or
As illustrated in FIG. 2, the outer peripheral surface of the base material 13 is lined with a material such as silicone rubber shrink tube (14
) consists of things.

In the hot air blocking mechanism IO having this structure, the expanded bubble 2 is supported by the circumferential side of each rolling element 12 arranged annularly around it, and the rolling element 12 rotates as the film moves upward. Therefore, even if the surface of the silicone rubber is scratched or deformed due to long-term use, there is no risk of scratches or the like occurring on the film surface.

3 and 4 relate to a second embodiment of the blown film production apparatus according to the present invention. In this embodiment, a hot air blocking mechanism 20 is provided on a support frame 6, preferably in a plane divided (e.g. A plurality of bases 21 are arranged in an annular manner (split), and a circuit is arranged in a centripetal manner as a whole, and is screwed onto each of the bases 21 so as to be movable in the direction towards the center of the bubble 2. It consists of a moving shaft 22 and a plurality of rolling elements 12 similar to those described above attached to the tips thereof, and by rotating each handle 23, the respective rotating shaft 22 is rotated.
are simultaneously slid in the radial direction (of the film manufacturing apparatus), and the diameter of the iris formed by each side wall of the plurality of rolling elements 12 arranged in an annular manner can be arbitrarily changed.

In the hot air blocking mechanism 20 of this embodiment, in addition to the effect of preventing scratches on the film surface due to the rotation of the rolling elements 12 similar to those in the previous example, the above-mentioned iris can be prevented by sliding the position of each rolling element 12. Since the diameter of the bubble can be changed, it is possible to arbitrarily adjust the diameter of the bubble inscribed in it.

As a result, the yield of the film can be improved.

In other words, when producing stretched film using the inflation method, a tubular film is usually flattened by being sandwiched between a pair of nip rolls after being stretched, and a slit is made at one end of the film to open it to make a flat film. If a film with a width of 1650 mm is manufactured using the iris of the formula, and the shipping specification is 43 Oas width, the remaining edge width will be 1650-430X 3 = 360 mm, which is the proportion (of loss) in the total. is 360/1
650 = 21.8%.

By using the movable iris mentioned above, the film width can be adjusted arbitrarily, so 430X3 + the required minimum selvedge width (
In this case, from the calculation formula (280m), it is sufficient to form a film with a width of 1570m, and the ratio of this width to the total width is 280/1570:17.8%, so 5%
The yield is improved.

Note that the hot air blocking mechanisms 1o and 2o described above are arranged in two directions in the vertical direction.
More than one stage may be provided, thereby making it possible to move the stretched film upward even more smoothly.

(Effects of the Invention) According to the present invention, it is possible to obtain a film produced by the inflation method that prevents the occurrence of scratches and improves the quality of the product.

[Brief explanation of drawings]

1 and 3 are cross-sectional explanatory views showing different embodiments of the blown film production apparatus according to the present invention, FIG. 2 is an enlarged cross-sectional view showing an example of rolling elements used in these apparatuses, and FIG. 4 3 is a partially enlarged plan view of the hot air blocking mechanism in the apparatus shown in FIG. 3, and FIG. 5 is a cross-sectional explanatory view of a film manufacturing apparatus using the conventional inflation method using the hot air blocking mechanism. (Explanation of main symbols) 2...Bubble, 3...Draft shield, 10.2
0... Hot air blocking mechanism, 12... Rolling element.

Claims (1)

[Claims] 1. A tubular draft shield is provided around the outer circumference of the expanded bubble, and hot air is blown into the tubular draft shield to keep the bubble warm, and a hot air shield is provided between the bubble and the bubble at the upper edge of the draft shield. In an inflation method film manufacturing apparatus having a mechanism, as the hot air blocking mechanism, a plurality of rolling elements made entirely of silicone rubber or made of a base material whose outer peripheral surface is lined with silicone rubber are arranged in an annular shape. Inflation method film manufacturing equipment. 2. The blown film production apparatus according to claim 1, wherein the rolling elements are balls or rollers. 3. Each of the rolling elements is mounted at the tip of a plurality of slide mechanisms arranged centripetally at the upper edge of the draft shield.
2. The inflation method film manufacturing apparatus according to claim 1, wherein a plurality of rolling elements are installed, and all of the rolling elements are provided so as to be movable in the radial direction by a slide mechanism.