JPS61238639A - Wound-up layer article of polyester film - Google Patents

Abstract

PURPOSE:To prevent a wound-up film layer article from collapsing its shape and generating creasing due to aging during storage thereof, and to eliminate the necessity of wrapping the outer surface of the article with a moisture proof material, by making the wind-up hardness of intermediate layer section of the wound-up film layer article greater than that of the outer surface layer section thereof. CONSTITUTION:As measures for makig the outer surface layers of a wound-up film layer article hard, there are used a contact pressure increment process, a tension increment process, and the combination of the former two. The contact pressure increment process comprises the step of winding up a film under such a condition that the value of contact pressure is increased by 20 to 100% in a range of 100 to 1,000m which is the final wind-up section of the film and which corresponds to the outer surface layers of the wound-up film layer article, and the tension increment process comprises the step of winding up the film at a low speed less than 100 m/min. in a range of 100 to 500m which is the final wind-up section to increase the tension of the film. Further, if these processes are used in combination, the effect thereby may be enhanced. Thus, the thickness of the air layer between the film layers is gradually decreased from the intermediate range to the outer surface layer so that the film becomes under the close contact condition to enhance its buckling strength, and therefore, no buckling occures even if the moisture absorption and swelling of the wound-up film layer article are brought about so that it is possible to prevent creasing from occuring, thereby, it is possible to eliminate an auxiliary measure such as, for example, a moisture proof cover without occurrence of slippage of the outer surface layer of the wound-up film layer article.

Description

[Detailed description of the invention] Industrial applications The present invention relates to polyester sheets and films.

Or it relates to a film roll in which a web (hereinafter simply referred to as a film) is wound around a core. More specifically, it is a roll-shaped layered body obtained by winding a uniaxially or biaxially stretched film made of polyester to a predetermined width and length, and includes a film slitting and winding process, a rewinding process, and a film processing process. Eshi (Surface treatment, coating.

Products that have been commercialized through printing, etc.).

It relates to a rolled layered body of semi-finished products.

Conventional technology and problems Conventionally, when winding a film into a roll, a certain tension and contact pressure are applied to adjust the air layer caught between the layers.
However, in the conventional winding properties, both the contact pressure and tension were constant or less than the range towards the end of the winding, so immediately after winding, even if the winding was in good condition, it took a long time. As time progressed, streak-like ridges appeared on the surface layer, which caused various defects in the secondary processing process.

For example, the streak-like ridge defect that occurs on the surface layer of a rolled film is caused by buckling deformation when the rolled film absorbs moisture from the surface layer and expands in the width direction. There is a tendency for this to occur significantly. These defects are described in Japanese Patent Application Laid-open No. 49-8514F1 and No. 49-1050.
This method is disclosed in Japanese Utility Model Publication No. 68 or Japanese Utility Model Publication No. 59-2699. As a solution to this problem, for example, in Japanese Patent Application Laid-Open No. 49-105068, the pressing force applied to the film roll that is being wound up is gradually reduced toward the end of the film to reduce the thickness of the air between the film layers near the surface layer. A method has been proposed to prevent buckling deformation due to expansion due to moisture absorption. However, since the winding near the surface layer is loose, there are other problems such as surface layer displacement during handling. Also,
Japanese Utility Model Publication No. 59-2699 proposes a method of wrapping the surface of the rolled film in a moisture-proof material to suppress moisture absorption and prevent buckling deformation. There is a problem that needs to be addressed.

OBJECTS OF THE INVENTION The object of the present invention is to provide a film-wound layer that prevents wrinkles, walnuts, etc. that tend to occur in polyester-wound products. The film roll according to the present invention does not lose its shape during storage, does not wrinkle over time, and does not require wrapping the surface of the film with a moisture-proof material. It is an object of the present invention to provide such a film roll.

It is common practice for the film rolls constituting the invention to be wound onto a core. In the process of forming this layered body, in other words, in the film winding process, when the film is wound up into a roll, the film forms layers. This film layer has a small amount of air interposed between adjacent film layers. If there is a large amount of air present in the film layer, the film layer can slip, and depending on the amount of air, the film layer can be soft or hard. In addition, if there is a relatively large amount of air between the film layers and the film is not held tightly between the layers, wrinkles can be suppressed when the film absorbs moisture and stretches. Since moisture absorption of the film occurs gradually during storage, wrinkles appear in the rolled product over a period of several days to several weeks. The present invention prevents wrinkles from forming over time in a film-wound layer by adjusting the amount of air between the layers.

The present invention relates to a rolled layered body formed by winding up a stretched and oriented polyester film into a roll shape, which is characterized in that the winding hardness of the surface layer portion of the rolled layered body is higher than the winding hardness of the middle layer portion. This is an ester film wound layer.

To explain the present invention, a stretched and oriented polyester film refers to a -axially stretched or biaxially stretched polyester film. Normally, a polyester film is stretched and oriented in the machine direction or (and) width direction at a stretching ratio of 2 to 5 times, and is subjected to heat treatment, surface treatment, etc. if necessary, but in the present invention, such a stretched and oriented state is used. Applicable to polyester film.

In the present invention, polyester refers to homobolymers, copolymers, or polymer blends of polyalkylene terephthalates such as polyethylene terephthalate, polybutylene terephthalate, and polyhexamethylene terephthalate, and polyalkylene naphthalene dicarboxylate typified by polyethylene naphthalene dicarboxylate. Contains carboxylates. Of course, fully aromatic polyesters are also included in the polyesters referred to in the present invention.

In the present invention, thin sheets, webs, laminated webs with metal or other polymer foils, etc. are collectively referred to as films. There is a concern that polyester may elongate (increase in area) when it absorbs a small amount of moisture (approximately 0.1 to 1% moisture content) in a dry state, and may wrinkle over time.
In thin films of μm or less, especially 25〃m or less,
The effects of applying the present invention are significant.

The term "rolled laminate" refers to a laminate wound around a core as shown in FIG. FIG. 1 shows an example of a conventional rolled product in which wrinkles (vertical wrinkles occurring in the longitudinal direction of the film) can be expected to occur on the surface layer.

In the present invention, the winding hardness is appropriately adjusted during the process of winding the layered body around the core, so that the winding hardness of the surface layer portion is greater than that of the middle layer portion. That is, in the process of forming a rolled product, the layered body of the present invention is wound tightly by changing the amount of air interlayered between the layers to reduce the amount of air interposed at the end of the winding. Therefore, in the process of forming a wound layer, the hardness of the wound layer is high near the core, gradually decreases in the intermediate region, and gradually increases in the surface layer after reaching the minimum hardness point. It has become.

In the polyester film wound layer of the present invention, the surface layer portion having a large degree of winding hardness is a portion corresponding to a length of about 100 to 1000 m in the longitudinal direction of the film from the winding end p.

To explain the method for winding the POIJ ester-wound layer of the present invention, the winding conditions (winding hardness) near the end of the winding are gradually increased compared to the conditions at the intermediate end, and the width and thickness of the film are increased. Although the conditions differ depending on the type of material, methods for hardening the surface layer of the wound layer include (a) treatment for gradually increasing the contact pressure, □ (b) treatment for gradually increasing the tension, and (c) a combination treatment of the above (a) and (b).

Here, the contact pressure gradual increase processing method is a method of winding under conditions such that the contact pressure is increased by 20 to 100% in a range of 100 to 1000 m at the end of the winding corresponding to the surface layer portion described above.

In addition, the tension gradually increasing process refers to 100~
This method increases the film winding tension by winding the film at a low speed of 100 m/mia or less in a range of 500 m. Moreover, even more effects can be obtained by combining the above-mentioned means. As a result of winding under these conditions, the air thickness between the film layers gradually decreases from the middle region to the surface layer, and the film becomes in close contact, improving buckling strength and preventing buckling even if there is moisture absorption and expansion from the surface. It can be confirmed that the appearance of wrinkles can be suppressed without any wrinkles. A rolled product rolled up under such conditions is an excellent rolled product that does not cause surface layer displacement and can eliminate the need for auxiliary means such as a moisture-proof cover, which can solve all 9 conventional problems at once. When this effect is expressed by focusing on the hardness of the rolled layer, it is shown in Figure 2.
Under conventional winding conditions, the hardness gradually decreases from the innermost layer to the surface layer of the wound layer, but when the winding conditions of the present invention are gradually increased, the hardness also shows a gradual decrease before the end of the winding. The inner layer hardness level also becomes a little higher. The hardness of a film when wound into a roll is determined by the rigidity determined by the film thickness and the thickness of the air layer between the layers, but for films of the same thickness, it is dominated by the air thickness between the eyebrows. A good winding condition can be formed by rolling the coil. In the present invention, a desired polyester layered body can be obtained by quantifying this control.

Example Polyethylene terephthalate biaxially stretched film (thickness 1
4 μm) was slit to a predetermined width (670 mm) and rolled up at a constant winding speed (300 m/ml s) to form a wound layered body. The total length of the film at this time was 6500 m. Table 1 shows the hardness of the surface layer of the wound layer obtained by adjusting the winding tension during the winding process and the occurrence of wrinkles (the number of perilla and the length of the wrinkles). In addition, the results of unwinding the rolled product and measuring the winding length and winding hardness at each part of the rolled layered product are shown in the second table.
Shown in the table.

Table 1 - 10 = Table 2 Inner layer hardness distribution of rolled products The hardness measurement specified in JIS K6301 can be applied to evaluate the rolled hardness, and the rubber hardness meter according to this standard (
Measured using a measuring device).

Furthermore, in the Examples, in order to distinguish the occurrence of wrinkles in the film-wound layer, a relative humidity of 90% at 40°C was used as a wrinkle acceleration test.
The specimens were left in a thermostatic chamber for 24 hours, and the appearance of wrinkles was observed.

From the examples, it has been found that defects such as wrinkles on the surface layer, which are conspicuous in conventional rolled products, can be eliminated by using the film-wound layer of the present invention in which the end portion of the roll is tightly wound.

Effects of the invention When winding a film into a roll to form a rolled layered body,
If the part within 1000 m, or at least 50 m, from the end of the winding is wound tightly, the effect that wrinkles will hardly occur over time will appear in the wound layer. And this scroll layer body is in a scroll form (
It has a good appearance (appearance) and there is no particular difference in handling compared to conventional products.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a conventional polyester film roll. FIG. 2 is a graph showing the relationship between the winding length of the film and the winding hardness when forming a film-wound layered body. In the figure, 3 is a graph showing the winding hardness of the wound layered body of the present invention. Yuy-cicada

Claims (1)

[Claims] 1. A polyester film layered body, which is a rolled layered body obtained by winding up a stretched and oriented polyester film into a roll shape, characterized in that the winding hardness of the surface layer portion of the layered body is higher than the winding hardness of the middle layer portion.