JPH0812196A - Film winding method - Google Patents

Abstract

PURPOSE:To provide a film winding method by which a plainer film like a polyester film for a video tape can be excellently wound by using an inexpensive cylindrical paper tube as a core, and preventing the occurrence of wrinkles or a granular protrusive defect of a film roll surface layer and a core part as seen in a film winding method using a cylindrical paper tube. CONSTITUTION:A film winding method is provided to wind a film by using a cylindrical paper tube on which the ratio M/A of flat compressive strength M (kg/100mm width) to a paper tube thickness A (mm) is not less than 14 and a flat compressive strength rate N per unit weight (g) is not less than 0.4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for winding a film having a smooth surface on a cylindrical paper tube, and more particularly to winding a polyester film for a magnetic recording medium suitable for audio tapes and video tapes. It is about how to take.

[0002]

2. Description of the Related Art Conventionally, when winding a film, a cylindrical paper tube or a rigid vinyl chloride cylindrical tube has been used as a winding core. However, speeding up the film manufacturing process, widening the film roll, and lengthening the film roll Deformation of the winding core becomes a problem with the increase in the number of windings, and foreign matter adhered to the winding core surface is increased by increasing the winding tension of the film to harden it in order to prevent misalignment during transport of the film roll. There is a problem in that the occurrence of a wrinkle-like raised defect on the outer surface of the film roll or the core portion and "crease" are caused.

In order to solve these problems, Japanese Unexamined Patent Publication No.
In Japanese Patent Laid-Open No. 1-162448, a method of winding a film using a plastic core having a surface roughness within a specific range is devised, but an increase in transportation cost and an expensive plastic due to an increase in weight due to the plastic core. Since the cost of the film roll is increased due to the use of the winding core and the problems associated with the disposal of the defective plastic winding core are highlighted, it is difficult to satisfy all of them.

[0004]

DISCLOSURE OF THE INVENTION The present invention solves the above problems and finds a film winding method using a less expensive cylindrical paper tube as a winding core and a conventional cylindrical paper tube. A film winding method that prevents the occurrence of "wrinkles" in the surface layer of the film roll and the core of the film roll and the defects of raised bumps, and also allows the smooth winding of films such as polyester films for video tapes. The purpose is to do.

[0005]

The object of the present invention is to provide a flat compression strength M (kg / 100 mm width) and a paper tube thickness A (m).
It is achieved by winding a film using a cylindrical paper tube having a ratio M / A with respect to m) of 14 or more and a flat compression strength rate N per unit weight (g) of 0.4 or more.

Here, the cylindrical paper tube is a rigid paper tube base paper (A
It is used after it is rolled into a cylindrical shape and then cut into a desired length, and the surface is polished or finished by spray painting with urethane resin, unsaturated polyester resin, alkyd resin, etc. For the purpose of the invention, it is preferred that the surface is polished and then buffed.

The method of winding and forming the paper tube base paper is not particularly limited, but after the base paper is cut to a desired size, it is impregnated with a resin or the like to form a flat roll several times, and the surface is subjected to a method such as hot pressing. Method of curing, or impregnating a strip-shaped paper tube base paper whose cross section is trapezoidal or parallelogram-shaped with resin etc., and then winding it up in a spiral shape (spiral shape) while stacking the cut surfaces, and hot pressing A method of curing the surface by a method such as the above is used, but for the purpose of the present invention, the cross-section of the paper core paper is processed into a strip shape so as to have a trapezoidal shape or a parallelogram shape, and seamless processing is performed. The product is then rolled up into a spiral tube into a cylindrical tube, which is then flat-rolled with a resin-impregnated paper tube base paper that is baked, surface-polished, and then subjected to high-pressure pressing to obtain the desired length. I prefer the way to cut Ku used.

As the film in the present invention, a film obtained by processing a synthetic resin such as polyester or polypropylene into a sheet or a film obtained by uniaxially or biaxially stretching the sheet is used. For the purpose of the present invention, A biaxially stretched polyester film is preferable.

The polyester applied above is produced by a polycondensation reaction of a bifunctional component such as an aromatic dicarboxylic acid or its alkyl ester and a glycol component, and particularly contains polyethylene terephthalate as a main component. Those are preferable.

The polyester may be a copolymer of a small amount of the third component as long as it does not impair the basic properties of the polyester film, or may be a mixture of these polyesters. Examples of the copolymerization component include dicarboxylic acid components such as 2,6-naphthalenedicarboxylic acid and isophthalic acid, oxycarboxylic acid components such as p-oxyethoxybenzoic acid, tetramethylene glycol, propylene glycol, neopentyl glycol and poly Examples thereof include diol components such as oxyalkylene glycol, p-xylylene glycol, 1,4-cyclohexanedimethanol, polyethylene glycol and 5-sodium sulforesordin. Of these, a copolyester obtained by copolymerizing a diol component such as polyethylene glycol is preferable in order to improve the adhesiveness of the film to the magnetic binder and to keep the chargeability due to static electricity or the like low. Further, in order to impart slipperiness to the film, inert particles may be contained in the polyester. Examples of such inert particles include calcium carbonate particles, silica particles, titanium oxide particles, kaolin particles, and talc particles.

The polyester film may be biaxially stretched by a conventional method, but for the purpose of the present invention, a biaxially stretched polyester film is preferably used.

The ratio M / A of the flat compressive strength M (kg / 100 mm width) and the paper tube thickness A (mm) of the cylindrical paper tube in the present invention is 14 or more, preferably 20 or more, and the unit weight (g) It is necessary that the flat compression strength ratio N per) is 0.4 or more, preferably 0.5 or more, and more preferably 0.6 or more. The flat compressive strength M (kg / 100 m
(m width) and paper tube thickness A (mm) ratio M / A or flat compressive strength ratio N per unit weight (g) is less than the above range, the film roll after winding up, especially for a video tape After the axially stretched polyester film is wound up, "wrinkles" are formed in the surface layer of the film roll, and a wrinkle-like raised defect is extremely likely to occur in the core portion of the film roll.

Here, the flat compressive strength M is a value obtained by cutting a 100 mm width at the central portion of the cylindrical paper tube with an autograph from the upper side of the circumference of the cylindrical paper tube to a load speed of 30 mm /
It is represented by the load applied (kg) at the primary inflection point of a straight line or a curve obtained when the relationship between the load strength and the amount of deformation when compressed in minutes is graphed.

The flat compressive strength ratio N is a value obtained by dividing the flat compressive strength M by 1000 and divided by the weight (g) of the cylindrical paper tube cut into a width of 100 mm.

In the present invention, the water content of the cylindrical paper tube is preferably 8% or less, more preferably 7% or less. When the water content is within the above range, even if the film roll obtained in the present invention is left for a long time or subjected to an aging treatment before use, "wrinkle" in the core portion of the film roll
Is unlikely to occur.

Here, the water content of the paper tube is represented by an average value when three points inside the paper tube are measured with a Kett paper moisture meter.

In the present invention, the shape of the film winder,
The method is not particularly limited, but in order to further clarify the effect of the present invention, a surface center wide method in which the winding drum is driven while a pressing force is applied to the film roll being wound by a touch roll such as a rubber roll. preferable.

[0018]

EXAMPLES The present invention will be further described based on examples. Example 1 A polyethylene terephthalate raw material containing 0.25% by weight of calcium carbonate particles having an average particle size of 0.9 μm as an additive was prepared and dried at 180 ° C. for 3 hours under reduced pressure (3 Torr). Next, the raw material was melt-extruded, and then wound around a casting drum by an electrostatic cast method to be cooled and solidified to prepare an unstretched sheet. This unstretched sheet was biaxially stretched by a conventional method to obtain a raw biaxially stretched polyester film having a width of 3 m and a thickness of 14 μm. This film roll is wound up at a winding speed of 300 m / min with a surface center wide type slitter, width 800 mm,
A film roll having a total length of 8000 m was obtained.

At this time, the film winding tension is 12.0 kg.
/ M, and the pressing force of the touch roll was 35 kg / m. Further, as the winding core, flat compression strength M (kg / 100 mm
Width) 330 kg / 100 mm width, paper tube thickness A is 12.2
5 mm, M / A is 26.9, weight per 100 mm width is 520 g, and flat compression strength rate N per 1 g of paper tube is 0.
64, water content 6.0%, outer diameter 175 mm, width 820 mm
The cylindrical paper tube of was used.

This film roll is heated at a temperature of 40 ° C. and a humidity of 7
The film was left to stand in an atmosphere of 0% RH for 5 days, but no "wrinkles" and no bump-like bulging defects were observed on the film roll surface or the film roll inner layer side when the film was cut.

Example 2 As a winding core, flat compression strength M (kg / 100 mm width) 1
95kg / 100mm width, paper tube thickness A is 8.0mm, M
/ A is 24.4 and the weight per 100 mm width is 320
g, flat compression strength rate N per 1 g of paper tube is 0.61, water content is 6.0%, a cylindrical paper tube having an outer diameter of 175 mm and a width of 820 mm is used, and the winding tension of the film is 13.5 kg / m.
A film roll was obtained in the same manner as in Example 1 except that the film length was 12000 m.

This film roll was allowed to stand for 5 days in an atmosphere of a temperature of 40 ° C. and a humidity of 70% RH as in Example 1, but no wrinkles were found on the surface of the film roll. Further, when the film was cut open, a slight bump-like bulge defect was observed at the extreme surface layer portion of the cylindrical paper tube of the inner layer of the film roll, but it was a practically satisfactory level.

Comparative Example 1 As a winding core, flat compression strength M (kg / 100 mm width) 1
65kg / 100mm width, paper tube thickness A is 12.25m
m, M / A is 13.5, weight per 100 mm width is 4
50 g, flat compression strength ratio N per 1 g of paper tube is 0.3
7. A film roll was obtained in the same manner as in Example 1 except that a cylindrical paper tube having a water content of 6.5%, an outer diameter of 175 mm and a width of 820 mm was used.

When this film roll was allowed to stand for 5 days in an atmosphere of a temperature of 40 ° C. and a humidity of 70% RH as in Example 1, "wrinkles" were observed on the surface of the film roll,
In addition, when the film was cut open, a large number of bump-shaped raised defects were generated on the surface of the film roll near the winding core.

Comparative Example 2 As a winding core, flat compression strength M (kg / 100 mm width) 1
05kg / 100mm width, paper tube thickness A is 7.9mm, M
/ A is 13.3, weight per 100mm width is 255
g, a flat compression strength ratio N per 1 g of paper tube is 0.41, a water content is 8.7%, a film roll is prepared in the same manner as in Example 2 except that a cylindrical paper tube having an outer diameter of 175 mm and a width of 820 mm is used. Got

This film roll is kept at room temperature and humidity of 65% R
When left in an H atmosphere for 4 hours, many "wrinkles" were observed on the surface of the film roll. Also, as in Example 1, the film was left for 5 days in an atmosphere at a temperature of 40 ° C and a humidity of 70% RH. When the film roll is incised, "wrinkles" are generated from the surface layer of the film roll over the entire inner layer portion in the vicinity of the surface of the cylindrical paper tube, and when the film roll is incised, "wrinkles" and a large number of wrinkle-like defects are formed. Was observed.

Comparative Example 3 As a winding core, flat compression strength M (kg / 100 mm width) 1
75kg / 100mm width, paper tube thickness A is 12.25m
m, M / A is 14.3, weight per 100 mm width is 4
Flat compression strength ratio N of 60 g per 1 g of paper tube is 0.3
A film roll was obtained in the same manner as in Example 1 except that a cylindrical paper tube having a water content of 9.7%, an outer diameter of 175 mm, and a width of 820 mm was used.

This film roll is kept at room temperature and humidity of 65% R
When left for 4 hours in H atmosphere, slight wrinkles were observed on the film roll surface. When the film roll was cut open, many wrinkles were found in the core.

[0029]

As described above, in the film winding method of the present invention, the total cost of the film roll can be supplied at a low cost by using an inexpensive cylindrical paper tube for the winding core. It is possible to provide a good film roll without defects such as "wrinkles" even when a smooth film such as a polyester film for audio and video tape is wound.

Claims (2)

[Claims] 1. Flat compression strength M (kg / 100 mm width)
And the thickness M (A) of the paper tube thickness A (mm) is 14 or more, and the flat compressive strength ratio N per unit weight (g) is 0.4 or more. Characteristic film winding method. 2. The film winding method according to claim 1, wherein the water content of the cylindrical paper tube is 8.0% or less.