JP3158871B2 - Winding method of polyester film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a polyester having a smooth surface.
It relates to a method for winding a Le film cylindrical paper tube, in particular, to a method for winding audio tape, a suitable polyester film for magnetic recording medium for a video tape.

[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. The deformation of the winding core becomes a problem as the film rolls, and the film winding tension is increased to prevent step deviation during transportation of the film roll. This causes problems such as generation of a bump-like raised defect on the outer surface of the film roll or the core portion, and "wrinkles".

In order to solve these problems, Japanese Patent Laid-Open Publication No.
In Japanese Patent Application Laid-Open No. 1-162448, a method of winding a film using a plastic core having a surface roughness in a specific range has been devised. Increasing costs of film rolls due to the use of cores, and problems associated with disposal of defective plastic cores, etc., have been highlighted, and it is actually difficult to satisfy all of them.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems and provides a method of winding a polyester film using a less expensive cylindrical paper tube as a core and a conventional cylindrical paper tube. A method of winding a polyester film that prevents the appearance of "wrinkles" and bumps on the surface of the film roll and the winding core, as well as smoother films such as polyester films for video tape. The purpose is to provide.

[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).
This is achieved by winding a polyester film using a cylindrical paper tube having a ratio M / A to m) of 14 or more and a flat compressive strength N per unit weight (g) of 0.4 or more.

Here, the cylindrical paper tube is a rigid paper tube base paper (A
Is cut into a desired length after winding into a cylindrical shape, and the surface is polished or spray-coated with urethane resin, unsaturated polyester resin, alkyd resin, etc. and then polished and used. For the purpose of the invention, it is preferable that the surface is polished and then further buffed.

[0007] The method of winding and forming the paper tube base paper is not particularly limited, but the base paper is cut into a desired size, impregnated with a resin or the like, flat-wound several times, and surface-pressed by a method such as hot pressing. After impregnating resin etc. into a strip of paper tube base paper whose cross section has been processed into a trapezoidal shape or a parallelogram shape, it is rolled up in a spiral shape (spiral shape) while overlapping the cut surfaces, and hot pressing Although a method of hardening the surface by a method such as is used, for the purpose of the present invention, seamless processing is performed on a paper tube base paper that is processed into a band shape such that the cross section becomes a trapezoidal shape or a parallelogram shape. After spirally winding this into a cylindrical tube, flattening a paper tube base paper impregnated with resin into a flat tube, baking the surface, polishing the surface, finishing high-pressure pressing, and then applying the desired length Prefer the method of cutting into Ku used.

[0008] The polyester film of the present invention is obtained by stretching a polyester Le further uniaxially or biaxially those processed into a sheet and the sheet is used, for the purposes of the present invention, biaxially oriented Polyester films are preferred.

The polyester used in the above is produced by a polycondensation reaction between a bifunctional component such as an aromatic dicarboxylic acid or an alkyl ester thereof and a glycol component, and particularly contains polyethylene terephthalate as a main component. Are preferred.

[0010] Such a polyester may be obtained by copolymerizing a small amount of the third component as long as the basic properties of the polyester film are not impaired, or may be a mixture of these polyesters. Examples of the copolymer component include dicarboxylic acid components such as 2,6-naphthalenedicarboxylic acid and isophthalic acid, oxycarboxylic acid components such as p-oxyethoxybenzoic acid, and tetramethylene glycol, propylene glycol, neopentyl glycol, Examples thereof include diol components such as oxyalkylene glycol, p-xylylene glycol, 1,4-cyclohexanedimethanol, polyethylene glycol, and 5-sodium sulforesorgin. Among them, a copolyester obtained by copolymerizing a diol component such as polyethylene glycol is preferred for improving the adhesiveness of the film to the magnetic binder and keeping the chargeability due to static electricity or the like low. In addition, inert particles may be contained in the polyester in order to impart lubricity to the film. 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, it is preferable that the polyester film is successively biaxially stretched.

In the present invention, the ratio M / A of the flat compression strength M (kg / 100 mm width) of the cylindrical paper tube to the thickness A (mm) of the paper tube is 14 or more, preferably 20 or more, and the unit weight (g). ) Is required to be 0.4 or more, preferably 0.5 or more, and more preferably 0.6 or more. The flat compressive strength M (kg / 100m
m width) and the thickness A (mm) of the paper tube or the flat compressive strength ratio N per unit weight (g) is less than the above range, the film roll after winding, especially the video tape. “Wrinkles” are formed on the surface layer of the film roll after winding up the axially stretched polyester film, and a bump-like raised defect is extremely easily generated in the core portion of the film roll.

Here, the flat compressive strength M is defined as a value obtained by cutting the cylindrical paper tube cut into a width of 100 mm at the center thereof by an autograph from the upper side of the circumference of the cylindrical paper tube at a load speed of 30 mm / mm.
It is expressed as a load (kg) at the primary inflection point of a straight line or a curve obtained when the relationship between the load strength and the deformation amount when compressed in minutes is obtained.

The flat compressive strength ratio N is obtained by dividing a value obtained by dividing the flat compressive strength M by 1000 by a weight (g) of a 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, "wrinkles" at the core of the film roll even when the film roll obtained by the present invention is left for a long time or subjected to an aging treatment before use.
Is unlikely to occur.

Here, the water content of the paper tube is represented by an average value when three insides of the paper tube are measured by 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 clarify the effect of the present invention, a surface center wide method in which the winding drum is driven while applying a pressing force to a film roll being wound with a touch roll such as a rubber roll is used. 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, after melt extruding the raw material, it was wound around a casting drum by an electrostatic application casting method, cooled and solidified to prepare an unstretched sheet. The 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. The raw film is wound up at a winding speed of 300 m / min by a surface center-wide slitter to a width of 800 mm.
A 8000 m long film roll was obtained.

At this time, the winding tension of the film is 12.0 kg.
/ M, and the pressing force of the touch roll was 35 kg / m. As the core, the 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 compressive strength N per 1 g of paper tube is 0.
64, water content 6.0%, outer diameter 175mm, width 820mm
Was used.

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

Example 2 A flat compression strength M (kg / 100 mm width) 1 was used as a core.
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, a flat compressive strength ratio N per gram of the paper tube is 0.61, a water content is 6.0%, an outer diameter is 175 mm, and a width is 820 mm. 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 changed to 12000 m.

This film roll was left in an atmosphere of a temperature of 40 ° C. and a humidity of 70% RH for 5 days in the same manner as in Example 1, but no wrinkles were found on the film roll surface. In addition, when the film was incised, a slight ridge-like prominence defect was observed in the outermost layer portion of the cylindrical paper tube in the inner layer of the film roll, but it was at a satisfactory level without any practical problem.

Comparative Example 1 A flat compression strength M (kg / 100 mm width) 1 was used as a core.
65kg / 100mm width, paper tube thickness A is 12.25m
m, M / A is 13.5, weight per 100mm width is 4
Flat compressive strength N per 50 g and 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 left for 5 days in an atmosphere of a temperature of 40 ° C. and a humidity of 70% RH in the same manner as in Example 1, generation of “wrinkles” on the film roll surface was observed.
Further, when the film was cut, a large number of bump-like raised defects occurred on the surface near the core of the film roll.

Comparative Example 2 Flat compression strength M (kg / 100 mm width) 1
05kg / 100mm width, paper tube thickness A is 7.9mm, M
/ A is 13.3 and the weight per 100 mm width is 255
g, a flat roll strength ratio N per g of paper tube is 0.41, a water content is 8.7%, and a film roll is produced 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. I got

This film roll is kept at room temperature and humidity of 65% R
When left in an atmosphere of H for 4 hours, many wrinkles were observed on the surface of the film roll, and the film was left for 5 days in an atmosphere of a temperature of 40 ° C. and a humidity of 70% RH as in Example 1. When the film roll was cut, "wrinkles" were generated from the surface layer of the film roll all over the inner layer portion near the surface of the cylindrical paper tube, and when the film roll was cut, "wrinkles" appeared on the core portion and a number of lumpy defects. Was observed.

Comparative Example 3 A flat compression strength M (kg / 100 mm width) 1 was used as a core.
75kg / 100mm width, paper tube thickness A is 12.25m
m, M / A is 14.3, weight per 100mm width is 4
Flat compressive strength N per 60g and paper tube 1g is 0.3
8. 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 under an atmosphere of H for 4 hours, generation of "wrinkles" was slightly observed on the film roll surface. When the film roll was cut, a large number of "wrinkles" were observed at the core.

[0029]

As described above, according to 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 as the core. It is possible to provide a good film roll free of defects such as "wrinkles" even when winding a smoother film such as a polyester film for audio or video tape.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A 3-1171 (JP, U) JP-B 3-75431 (JP, B2) JP-B 51-39115 (JP, Y1) (58) Field (Int.Cl. ⁷ , DB name) B65H 75/08 G11B 5/84

Claims (2)

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