JP3505921B2 - Nip roll device and nip method for sheet material - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nip roll device and a nip method for a wide sheet-like material, for example, a sheet-like material such as a plastic film, paper, metal cloth, cloth or non-woven cloth. In particular, it relates to a take-up nip roll device for stretching a plastic film and a nip method.

[0002]

2. Description of the Related Art In the production of sheet-like materials such as plastic films, papers, metal cloths, cloths and non-woven fabrics, the sheet-like materials are conveyed or continuously thinly crushed and stretched. A nip roll device is generally used as the device.

In particular, in the production of plastic sheets and plastic films, a roll stretching device is generally known as a device for stretching (longitudinal stretching) the film in the flow direction. An example of such a stretching device is shown in FIG.

FIG. 2 is a schematic view showing an example of a roll stretching (longitudinal stretching) apparatus.

The film 2 that has entered the stretching device 1 is heated by a preheating roll 3, stretched by a take-up nip roll 4 kept at a high speed, and cooled and fixed by a cooling roll 5.

Particularly in a machine for stretching a film having a wide width, it is extremely important to impart uniform stretching to the film in the width direction in order to make the dimensions and physical properties of the film uniform. The uniform drawing in the width direction is obtained by a uniform take-up force in the width direction, but the uniformity of the take-up force depends on the uniformity of the pressing force (nip force) of the take-up nip roll 4.

Usually, such a take-up nip roll 4 is
It is composed of an upper roll 4a and a lower roll 5a.
An example of the upper roll 4a is shown in FIG.

FIG. 3 is a sectional view showing an example of an upper roll in a conventional take-up nip roll.

The upper roll 4a is a free roll whose both ends are rotatably supported by bearings (not shown). A pressing device 6 such as an air cylinder is used to apply a downward pressing force to the rolls via the bearings at both ends, thereby forming a nip between the rolls and the lower roll 5a. The upper roll 4a is usually a rubber roll in which an elastic body such as rubber 8 is wound on the surface of a cored bar 7.
As a roll for a wide film, a long roll is used according to the film width.

The lower roll 5a is usually a drive roll whose surface speed is kept higher than that of the preheating roll, and the film is stretched by this speed difference. Further, the lower roll 5a also serves as a cooling roll, and the surface thereof is metal for uniform cooling, and has a complicated structure in which a coolant such as water flows inside the roll (not shown).

In the case of a wide film, a great pulling force is generated, so a large nip force is applied to such a pulling nip roll.

However, in the structure in which the pressing force is applied through the support portions at both ends of the long roll in this way, the roll is easily bent as shown in FIG. There is a drawback that you can not nip.
As a result, there is a problem in that stretching unevenness in the width direction of the film, meandering of the film, and defects such as wrinkles and scratches are likely to occur. FIG. 4 is an explanatory view of roll deflection in the conventional take-up nip roll.

As a means for avoiding this, a method is known in which the surface of the upper rubber roll has a drum shape (crown shape), but it is also necessary to increase the crown amount in order to compensate for the large deflection. Therefore, there is a large difference in the roll surface speed due to the difference in diameter between the thick central portion and the thin end portions, which causes problems such as scratches on the film and uniform stretching.

As another means for avoiding this, an upper roll having a center load (CL) structure as shown in FIG. 5 is known. It can be expected that the deflection of the core will be greatly improved by using this CL structure.
Due to the double structure of the core and the inner shaft, the roll weight becomes very large, and as a result, the critical speed becomes small. Therefore, it cannot be driven at high speed and is not practical. In addition, a long CL roll is not preferable because it is very difficult to manufacture, the manufacturing cost is high, and the manufacturing risk is large.

As another means for avoiding this, there is known a method of positively using the self-weight deflection of the upper roll, for example, Japanese Patent Publication No. Sho 62-28059. This is because the upper roll uses a roll that is heavy and has low rigidity and is easily bent, and the lower roll is a roll that has high rigidity and is hard to bend. It is a method of nipping both rolls while bending.

However, this method is not sufficient.
This is because a roll having a small outer diameter has to be used in order to reduce the rigidity, and it is difficult to obtain a sufficient nip force even if the roll is pressed against the lower roll while pulling it up.
Further, since the roll weight is larger than the rigidity of the upper roll, the critical speed is also small. This is because it cannot be driven at high speed and is not practical.

Further, in this case, the lower roll needs to have high rigidity and is not easily bent, but it is difficult to increase the rigidity of the lower roll having a complicated cooling structure. Alternatively, it is conceivable to increase the outer diameter of the conventional lower roll to increase the rigidity, but it is necessary to greatly change the front and rear roll arrangement and the drive system, whichever is difficult in practice. .

As described above, it has been difficult in any of the conventional methods to achieve high-speed operation while preventing deflection and forming a uniform nip.

[0019]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art. For a sheet material such as a plastic film having a wide width, stretching unevenness in the film width direction is obtained. We do not provide a nip roll device or nip method for a sheet-like product that can achieve a uniform nip that does not cause meandering of the sheet-like product and defects such as wrinkles and scratches by a simple method, and that can operate at high speed and has good productivity. It is what

[0020]

The structure of the present invention for achieving the above object is as follows.

The sheet-like nip roll device of the present invention is a nip roll device having a pair of nip rolls for pressing a traveling sheet-like product from above and below, wherein the upper roll is formed of a pipe and the central portion in the axial direction. of
It is characterized by incorporating a weight inside the roll .

Further, in the above nip roll device,
The weight is characterized in that it is one that has less than 1/4 of the length of the face length of the upper roll.

Furthermore, the upper roll axial ends
Is rotatably supported .

The nip roll device is a nip roll for stretching which stretches a sheet.

Further, the sheet-like material nip method of the present invention,
Alternatively, the stretching method is characterized in that the sheet-like material is nipped or stretched by using the nip roll device. Further, the stretched film manufacturing apparatus of the present invention includes the above-mentioned two units of the nip roll apparatus having a pair of nip rolls that press the film heated by the preheating rolls from above and below .
Extends between the Ppuroru, then Oite apparatus for producing a stretched film is cooled by the cooling roll, the nip roll apparatus includes an upper roll, it is constituted by a pipe,
In addition, a weight is incorporated inside the roll at the center in the axial direction.
It is characterized by being

Further, in the method for producing a stretched film of the present invention, the film heated by the preheating roll is stretched between the respective nip rolls of the nip roll device having a pair of nip rolls for pressing from above and below, and then cooled by the cooling roll. Oite the manufacturing method of the stretched film, as the nip roll device, the upper roll, configured by a pipe
And inside the roll at the center in the axial direction.
It is characterized in that it is stretched by using a nip roll device in which a sheet is incorporated . Further, the sheet-like material of the present invention
Nip roll is a nip roll that presses a sheet material.
In, in the axial direction of the cored bar composed of a pipe
It has a weight built into the center.
To collect. Further, the core metal has bearing parts at both ends.
It is characterized by being

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION Nip rolls and nipples of the present invention
In the roll device and the nip method, since the weight is incorporated in the central portion of the upper roll in the axial direction , the weight is heavier than the outer portion thereof. Therefore, as shown in FIG. Pressed, the deflection of the roll is improved so that a uniform nip can be obtained.
FIG. 6 is an explanatory diagram showing an example of roll deflection when the nip roll device of the present invention is used.

Further, since the deflection is improved without reducing the rigidity of the upper roll, high speed operation is possible and the productivity is good.

Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of an upper roll 4a constituting a nip roll device according to an embodiment of the present invention.

The core metal 7 is composed of a pipe, and a rubber 8 is wound on the core metal 7. Although the material of the core metal 7 is not specified,
In addition to commonly used carbon steel materials, any material can be used as long as it can form a roll, and other known materials such as stainless steel and aluminum can be used. Further, it may not be a metal material. For example, it is more preferable to use a composite material such as carbon fiber reinforced resin (CFRP).

The rubber 8 may be an elastic body which itself has a function of absorbing deflection and vibration and has durability against a large nip pressure, and is known as silicone rubber, chloroprene rubber, EPDM, NBR, urethane rubber, etc. The material of can be used. Also, the rubber structure does not have to be a uniform single layer,
2 for hardness distribution, different grade and hardness
It may be laminated in more than one layer.

The present invention may also be combined with a crown. Even if the amount of crown is smaller than the conventional amount, a uniform nip can be obtained.

In the case of a nip roll device for a calendar, for example, the upper roll may not be a rubber roll, and the surface may be plated, ceramic coated or polytetrafluoroethylene (for example, DuPont trade name "Teflon") coated. The above can also be applied.

The bearing portion remains the same as the conventional roll,
Different materials and configurations can be used as required.

A cylindrical lead weight 10 is incorporated in the central portion inside the core metal and is fixed by a bolt.
The weight does not have to be made of lead, but metal such as gold or other high density material can be used. Further, it does not have to be a solid material, and various powders and granules or those in which a fluid is enclosed can be used. The use of such materials is preferred in order to suppress vibrations.

The shape can be freely determined in accordance with the nip characteristics, and for uniform nip, it is preferable that the length is within 1/4 of the roll surface length. The cross-sectional shape of the weight may be solid or hollow, or may not be circular. The contact with the core may be partial. For the deflection that normally occurs as shown in FIG. 4, it is preferable that the weight of the central portion is 1.5 times or more larger than that of the outer portion, and it is more preferable that the weight is 3 times or more larger.

As a method for fixing the weight, various known methods suitable for the material can be used. For example, shrinkage fitting, adhesion, welding, screw fastening, or the like may be performed, or the core metal may be manufactured so as to have a weight portion from the beginning.

In this embodiment, since the roll structure other than the weight is the same as the conventional one, it is only necessary to add the weight to the structure of the conventional roll, and for this reason, there is an advantage that no special manufacturing method is required and the cost is low. is there. Further, if the existing roll is modified and implemented, the cost can be further saved.

[0040]

[Example] Upper roll 4a constituting a nip roll device
As roll surface length 5000mm, roll outer diameter 250m
m carbon steel core metal coated with EPDM rubber was used, and a lead weight was inserted into the center of the core metal over a range of 1000 mm in the width direction and fixed, and was used in a longitudinal stretching device for polyester films. The nip was more uniform than the roll, and film defects were reduced. Roll speed 250
Even when operating at rpm or higher, vibration could be suppressed to a low level. The weight of the central portion was three times that of the outer portion.

[0041]

As described above, the nipple of the present invention is used.
Lumpur, according to the nip roll device and the nip method, have weights incorporated in the axially central portion of the upper roll
Since because heavier than its outer portion, it is possible deflection of the central portion to obtain a uniform nip is improved, as compared with the conventional method, film or meandering, causing no defects such as wrinkles and scratches .

Further, since the deflection is improved without reducing the rigidity of the upper roll, high speed operation is possible and the productivity is good.

[0043] Further, a method of heavy axial central portion easy <br/> flight implementation law Ru can variously selected, since especially the roll is composed of a pipe, and that the weights therein A uniform nip can be achieved simply by inserting and fixing.

Even when a crown is attached to the upper rubber roll, it can be made smaller than the conventional method.
There is no significant difference in surface speed, the film is not scratched, and uniform stretching is possible.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an upper roll that constitutes a nip roll device according to an embodiment of the present invention.

FIG. 2 is a schematic view showing an example of a roll stretching (longitudinal stretching) device.

FIG. 3 is a cross-sectional view showing an example of an upper roll of a conventional take-up nip roll.

FIG. 4 is an explanatory diagram of roll deflection in a conventional take-up nip roll.

FIG. 5 is a cross-sectional view of an upper roll in a conventional take-up nip roll.

FIG. 6 is an explanatory view showing an example of roll deflection when the nip roll device of the present invention is used.

[Explanation of symbols]

1: Stretching device 2: Film 3: Preheating roll 4: Take-up nip roll 4a: upper roll 5: Cooling roll 5a: lower roll 6: Pressurizing device 7: Core 8: rubber 9: Inner axis 10: Weight

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-56-132250 (JP, A) JP-A-61-267650 (JP, A) Actual development Sho-58-137652 (JP, U) (58) Field (Int.Cl. ⁷ , DB name) B65H 27/00

Claims (11)

(57) [Claims] 1. A nip roll device having a pair of nip rolls for pressing a traveling sheet-like material from above and below,
The upper roll consists of a pipe and is axial
A nip roll device for a sheet-like product, characterized in that a weight is incorporated inside the roll in the central portion . Wherein said weight is a nip roll apparatus according to claim 1 sheet of wherein a is one having less than 1/4 of the length of the face length of the upper roll. Wherein the upper roll is rotated own the axial ends
The nip roll device according to claim 1 or 2, wherein the nip roll device is a sheet-like product that is supported at present . 4. The nip roll device for a sheet material according to claim 1, wherein the weight of the central portion in the axial direction of the upper roll is set to be 1.5 times larger than that of the outer portion. 5. The nip roll device for a sheet material according to claim 1, wherein the nip roll is a stretching nip roll for stretching the sheet material. 6. A nip method for a sheet-like article, comprising nipping a sheet-like article using the nip roll device according to any one of claims 1 to 4. 7. A method for stretching a sheet-like material, which comprises stretching the sheet-like material using the nip roll device according to claim 5. Said 8. A nip roll device having a pair of nip rolls to press the heated film from above and below by preheating rolls extending between each nip roll, then your apparatus for producing a stretched film is cooled by the cooling roll <br / > In the above nip roll device, the upper roll is
And inside the roll at the center in the axial direction.
An apparatus for producing a stretched film, characterized by incorporating a weight . 9. A method for producing a stretched film, wherein a film heated by a preheating roll is stretched between the nip rolls of a nip roll device having a pair of nip rolls for pressing the film from above and below, and then cooled by a cooling roll. > There are, as the nip roll device, the upper roll, Pas
Inside the roll at the center in the axial direction.
A method for producing a stretched film, which comprises stretching using a nip roll device in which a weight is incorporated in a part . 10. A nip roll for pressing a sheet material
And a core made of a pipe, and the center of the core in the axial direction.
Characterized by having a weight incorporated inside the section
Nip roll for sheet material. 11. The cored bar has bearing portions at both ends.
The sheet according to claim 10, which is a sheet.
Nip roll for objects.