JPS6288754A - Winding method for polymeric film - Google Patents

Abstract

PURPOSE:To aim at the preventions of slackness in the central part of a film and seaweedlike deformation at its end part, by setting the temperature of a cylindrical core in winding to be higher at 10-100 deg.C than that of the polymeric film. CONSTITUTION:Temperature in a cylindrical core 2 is set to be higher at 10-100 deg.C than that of a polymeric film 1 by various method (for example, a method of setting heater included). When less than this range is the case, winding tight in the cylindrical core 2 comes too much after the winding, whereby this polymeric film is deformed as seaweedlike form. And, when more than this range is the case, it shrinks with heat and size uneveness occurs, so that the desirable range is between 15-70 deg.C. After the polymeric film is wound up, the cylindrical core is cooled by various method, for example, forced cooling or the like by a fan till temperature in the cylindrical core becomes equalized to that of the film. A cooling velocity is desirable to be 1-100 deg.C/hr. With this constitution, flatness quality in the film is sharply improvable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for winding a polymer film. More specifically, the present invention relates to a method for winding a polymer film that does not cause wrinkles or sag.

[Conventional technology]

The polymer film is wound around a cylindrical core, and various types of cylindrical cores with different shapes and materials are used.

[Problem that the invention seeks to solve]

However, when a polymer film is wound into a roll using such a conventional cylindrical core, the polymer film near the cylindrical core becomes wakame-like at the edges and sag at the center, resulting in a significantly flat surface. This resulted in a disadvantage of decreased performance.

(Means for Solving the Problems) The present invention provides a method for winding a polymer film into a roll using a cylindrical core as a core, in which the temperature of the cylindrical core during winding is set at 10% higher than the temperature of the polymer film. ~100'
It is characterized by being wound up at a high height.

The polymer film in the present invention may be any known polymer film, and specifically includes polyethylene film, polypropylene film, polystyrene film, polyvinyl chloride film, polyvinyl alcohol film, and polyethylene terephthalate film. , a polyester film, a polyamide film, a polycarbonate film, an acetate film, etc., which are -axially stretched, preferably biaxially stretched. Note that the thickness is not particularly limited, but is 1~
A thickness of about 500 μm is preferable.

In addition, the film has a heat shrinkage rate of 0.1 for 10 minutes at 150'C.
About 10% is preferable.

The cylindrical core may be made of any material, such as metal, resin such as polyethylene, polypropylene, polyvinyl chloride, Bakelite, epoxy, nylon, ABS, paper, glass fiber, or a composite thereof. Although not particularly limited, it is preferable to use a material having a larger coefficient of thermal expansion than a polymer film, specifically polyvinyl chloride, Bakelite, etc. Further, it is more preferable that the thermal expansion coefficient is 2×10 to 20×10 −5 larger than the thermal expansion coefficient of the polymer film.

The shape of the cylindrical core may be determined as necessary, such as a cylinder or a hollow cylinder.

In the present invention, when winding a polymer film onto a cylindrical core, the temperature of the cylindrical core during winding (from the beginning of winding to the end of winding) is set to 10 to 10% higher than the temperature of the polymer film.
It is necessary to wind the film at a high temperature of 00'C. If it is lower than this range, the cylindrical core will become too tightly wound after being wound, and the polymer film will be deformed into a wakame-like shape. Also,
If it is higher than this range, the polymer film will shrink due to heat, resulting in dimensional unevenness, which is not preferable. A more preferable range is 15
~70°C, with a roughly preferred range of 20~40'C
It is.

Methods for raising the temperature of the cylindrical core higher than that of the polymer film include a method of attaching a heater to the cylindrical core and a method of heating the cylindrical core in advance, and any of these methods may be used.

In addition, one variation in which a polymer film is wound around a cylindrical core,
The cylindrical core is cooled to a temperature equivalent to the temperature of the film while the film is wound on the cylindrical core. As a cooling method, for example, air temperature (approximately 25°C)
A natural cooling method in which the device is left to cool in the air, a forced cooling method using a fan, or a forced cooling method in which the device is cooled with water can be used. The cooling rate is preferably in the range of 1 to 100'C/hour. Further, both the polymer film and the cylindrical core may be cooled to 30'C or less.

[Effect]

The reason why the flatness quality is significantly improved by the present invention is as follows.
This is thought to be because the tightening force of the polymer film can be relaxed by increasing the temperature of the cylindrical core.

[Effects of the Invention] The present invention provides that during winding, 1
Since a cylindrical core having a high temperature of 0 to 100'C is used, the film that is unwound after the temperature of the cylindrical core becomes equal to the temperature of the polymer film does not wrinkle or sag.

The winding method of the present invention is particularly preferable for winding photographic films, label films, optical films, magnetic tape films, magnetic sheet films, printing films, etc., which require flatness quality.

[Measurement method and evaluation method of the present invention]

(1) Measure the film temperature using a contact thermometer. Alternatively, a non-contact thermometer may be used.

(2) Temperature of cylindrical core A1 before winding Measure the outside center of the core.

89 After winding, the inner center part of the hollow cylindrical core is measured, and the cylindrical end face part of the non-hollow cylindrical core is measured.

(3) Flatness of the film After leaving the rolled film wound around a cylindrical core at 25°C for one week, the film is once wound back onto another core, and the length is determined from the beginning of the winding of the first cylindrical core. A 100 m section was taken out and spread out for 1 m, and the film was observed for sagging and seaweed-like deformation, and evaluated using the following criteria.

Palanque: No deformation 8 Rank: Slight deformation observed C rank: Significant seaweed-like deformation Note that sagging of the film and seaweed-like deformation occur approximately at the center of the film, as shown in Figure 1. The former occurs at the edges of the film, and the latter occurs at the edges of the film.

However, 1 indicates the film, 2 indicates the winding core, A indicates wakame-like deformation, and B indicates sagging.

(Example) Hereinafter, the present invention will be explained based on Examples.

Example 1 Thickness: 15 μm, Width: 600 nvn, Length: 500 Qm
polyethylene terephthalate film and inner diameter 14.0
A cylindrical core made of polyvinyl chloride with a diameter of 150 mm and a width of 700 mm was prepared. A heater is installed inside this cylindrical core and the cylindrical core is heated to 50'C, and a polyethylene terephthalate film (25°C) is heated.
I rolled it up. The cylindrical core was 25°C hotter than the film. The coefficient of thermal expansion of the polyethylene terephthalate film was 2×10 −5 and that of the cylindrical core was 8.0×10′. Further, the rolled film was left in a room at 25° C. to cool. The cooling rate of the cylindrical core was 10°C/hour.

The film was left at 25° C. for one week and then rewound. When the film was observed, there was no wakame-like deformation at all, and the film was ranked A.

Comparative Example 1 It was wound up in the same manner as in Example 1 except that the temperature of the cylindrical core was 25°C.

When the film was observed in the same manner as in Example 1, it was found that the film was deformed into a wakame-like shape, and the rank was C, which made it unsuitable for practical use.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a film wound around a cylindrical core and a partially unwound state of the film. 1; Film 2: Cylindrical core A; Wakame-shaped deformation B; Sagging

Claims (1)

[Claims] A method of winding a polymer film into a roll around a cylindrical core, characterized in that the temperature of the cylindrical core during winding is 10 to 100°C higher than the temperature of the polymer film. How to wind the film.