JP2004161485A - Film winding-out method and its device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stably wind out a thin film with a minimum tension from a mill roll, to prevent variation of winding-out tension from affecting a next process. <P>SOLUTION: A film winding-out method separates a thin film F made of plastic with adhesion from a winding roll R which the thin film F is wound around, and winds out the thin film F through a pulling-in roller 2. Speed difference between the outer peripheral speed of the winding roll R and the peripheral speed of the pulling-in roller 2 is adjusted so that the tension of the film F caused by the speed difference is equal to or slightly greater than the force of tearing the film off the winding roll, to obtain a theoretically lowest or near the lowest tension. The direction of the winding tension is set in an approximate perpendicular to the tangent of the roll at the tear off point of the winding roll R. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a thin film having a relatively elastic property, such as a plastic base adhesive tape, a masking film, a stretch packaging film, a food wrap film, and a surface adhesiveness or a self-adhesiveness (hereinafter collectively referred to as adhesiveness). The present invention relates to a film unwinding method and an apparatus for stably unwinding a film from a winding roll (mill roll) with a minimum tension.
[0002]
[Prior art]
Unwinding a film from a take-up roll (hereinafter, referred to as a mill roll) formed by winding a thin film such as a plastic film (hereinafter, simply referred to as a film), sending the film to the next step, and performing various processing and processing include, for example, It has been widely practiced to unwind a film from a mill roll in a slitter winder, cut the film into a plurality of narrow bands, and wind each of the films into a narrow roll.
[0003]
FIG. 1 shows a configuration of a typical unwinding machine applied to the above-mentioned conventional unwinding, in which a mill roll R is rotatably supported by a machine frame, and a film F is guided by a guide roller 1 to be a take-up roller. 2 to be unwound from the mill roll R.
At this time, the tension is generated by setting the magnitude of the tension by the tension setting device 4 and exciting the unwinding brake 5 (continuous slip) connected to the core shaft S of the mill roll R via the control circuit 6. The actual tension value is detected by the tension detector 3 and constitutes a closed-loop automatic control system in which the tension is fed back to the set tension.
When the rotation resistance of the mill roll R is larger than the required unwinding tension, the motor M may be used instead of the unwind brake 3 so as to reduce the rotation resistance of the mill roll R in the unwinding direction.
[0004]
[Problems to be solved by the invention]
However, in the conventional unwinding as described above, when the unwinding tension for unwinding the film from the mill roll R is higher than an appropriate value or fluctuates, unevenness occurs in the cutting width, and wrinkles are formed on the film. If it occurs or is extremely severe, a large tightening force is applied to the winding core for winding the cutting band, which may even cause the winding core to be partially depressed. Or may occur.
[0005]
Moreover, when the unwound film F has no tackiness at all, the direction in which the film F separates from the mill roll R is the tangential direction of the mill roll R shown by the solid line in FIG. The tension balances with the rolling resistance of the 100% mill roll R. However, when the film F has adhesiveness, it is necessary to generate a force for peeling the film F from the mill roll R. Therefore, as shown in FIG. Is a vector-like resultant of the rotational resistance Pt of the mill roll R and the force Pr for separating the film from the mill roll, and the direction of the resultant force is an angle θ from the tangential direction of the mill roll at the peeling point as shown by the broken line in FIG. The direction is inclined.
[0006]
For this reason, conventional methods and controls for handling unwinding tension are limited to treating the tension as the above-described resultant force. Let's deal with this from the two factors of the rolling resistance of the mill roll and the peeling resistance of the film. However, it was difficult to stably unwind a film having elasticity and adhesiveness with low tension.
[0007]
In particular, when the film has the above-mentioned tackiness, the magnitude of the unwinding tension and its variation greatly affect the finishing and finishing of the film in the next process, which hinders the generation of defective products and the improvement of productivity. The development of a method and an apparatus for unwinding a film from a mill roll stably with appropriate low tension has been an important issue.
[0008]
The present invention addresses the above-mentioned situation, and in particular, finds a relationship between a rotational direction force to be applied to the mill roll when the film is unwound from the mill roll and a peeling force and a tension for peeling the film from the mill roll, thereby relatively reducing the tension. Unrolls a thin film with elasticity and surface tackiness from a mill roll with minimum tension and stably, preventing the effect of fluctuations in unwinding tension on the next process and preventing defective products from occurring. It is intended to improve the performance.
[0009]
[Means for Solving the Problems]
That is, the method of the present invention that meets the above-mentioned object is, in unwinding a film rolled out from a mill roll formed by winding a thin film of an adhesive plastic or the like and winding the film from a take-off roller, Adjust the speed difference so that the film tension generated by the speed difference between the outer peripheral speed and the peripheral speed of the take-off roller is equal to or slightly larger than the force for peeling off the film from the mill roll. It is characterized in that unwinding is performed as the lowest value or a slightly larger value.
[0010]
According to a second aspect of the present invention, in the unwinding, the film is unwound in a direction substantially perpendicular to a tangent of the roll at the peeling point of the mill roll.
[0011]
Claim 3 relates to an apparatus for carrying out the method, wherein a mill roll rotatably supported by a rotatable mill roll support arm, and a take-off roller for peeling off and pulling the film against the adhesive force from the mill roll. And a speeder belt that comes into pressure contact with the mill roll in all ranges from the maximum diameter to the minimum diameter of the mill roll, and the mill roll has a speed difference between a peripheral speed of the mill roll and a peripheral speed of the take-up roller. By adjusting the speed of the speeder belt to be adjusted, the upper surface position of the film immediately after peeling off from the mill roll is kept constant to keep the film peeling angle θ at about 90 °, and the mill roll changes with the progress of unwinding. The center position of the mill roll and the relative positional relationship of the take-off roller corresponding to the outside diameter of the The configuration is such that the control is such that the straight line connecting the touch points intersects the outer periphery of the mill roll at that time substantially at right angles to the tangent of the mill roll.
[0012]
It is preferable that the distance to the upper surface of the film immediately after the peeling is detected by a detector, and thereby the speed of the speeder belt is controlled so as to keep the position constant.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings.
[0014]
The present invention, when peeling the film from the mill roll obtained by winding the film having adhesiveness as described above and winding the film by the take-off roller, the film generated by the speed difference between the outer peripheral speed of the mill roll and the outer peripheral speed of the take-up roller By adjusting the speed difference so that the internal stress is equal to or slightly greater than the force for peeling the film from the mill roll, the unwinding tension is set to the theoretically lowest value or a slightly larger value close to this, and the direction of the tension. At a peeling point at a right angle to the tangent of the mill roll, that is, in the normal direction of the mill roll.
[0015]
Hereinafter, the basic unwinding of the present invention will be theoretically studied and described with reference to FIGS. 2 and 3. FIG. 2 shows that the adhesive film F is given to the mill roll R when unwinding from the mill roll R. The relationship between the power in the rotational direction to be applied, the peeling force for peeling the film F from the mill roll R, and the tension is shown.
[0016]
In FIG. 2, the effective component of the rotational force is the point of action of the tension on the mill roll in the tangential direction of the mill roll with a magnitude of Pt, and the effective component of the peeling force is the point of action of the tension on the mill roll (peel point). It works in the direction perpendicular to the tangent of the mill roll, that is, in the normal direction of the mill roll, with the magnitude of Pr.
The resultant force resulting from the vector synthesis of these two effective components becomes the tension P, and the direction of the resultant is inclined by an angle θ with respect to the tangent to the mill roll.
And since the directions of Pt and Pr are 90 °,
θ = tan ⁻¹ Pr / Pt (1)
P = Pr / sin θ (2)
It becomes.
[0017]
Now, if the mill roll rotational force is forcibly applied by another means without depending on the tension, the only active ingredient that unwinds the film from the mill roll due to the tension is the peeling force.
If the direction angle θ of the tension is increased in this state, the force f required for peeling is constant, and the component force Pr in the peeling direction due to the tension is balanced with the force f. Therefore, the absolute value of the tension P should be reduced from the above equation (2). And the limit is P = Pr at θ = 90 °.
Therefore, (1) a force for rotating the mill roll is provided by another means without depending on the tension.
(2) The direction of the tension P is applied in the normal direction of the mill roll at the peeling point of the film.
If the above two requirements can be satisfied stably at the same time, it is theoretically possible to unwind the adhesive film with a tension (theoretical minimum tension) sufficient to peel off the film from the mill roll in the film normal direction.
[0018]
FIG. 3 is a skeleton diagram showing a concept for realizing the above theory.
The mill roll R is rotatably supported by a machine frame, and a speeder belt 7 is in pressure contact with an outer periphery of a lower portion of the mill roll R. The traveling of the speeder belt 7 applies a rotational force to the mill roll R. The running speed of the speeder belt 7, that is, the outer peripheral speed Vs of the mill roll R can be changed with respect to the peripheral speed Vr of the take-up roller 2.
The take-up roller 2 is constituted by a pair of upper and lower nip rollers in the figure, and is used for peeling off the film F from the mill roll R and transferring the film F to the next step, and is actively driven at a peripheral speed Vr.
[0019]
When the stretchable film is pulled in the above state, the Hooke's law can be applied within the elastic limit.
That is, the relationship between the strain ε, the stress σ, and the Young's modulus E is σ / ε = E (3)
It becomes.
[0020]
Therefore, when this relationship is applied to the embodiment of the film in FIG. 3, the following is obtained.
(1) The difference ΔV between the peripheral speed Vr of the take-up roller and the peripheral speed of the mill roll, that is, the peripheral speed Vs of the speeder belt 7 is applied to the film from the peeling point b of the mill roll R to the nip point c of the take-up roller 2. Distortion has occurred.
That is, ΔV = Vr−Vs, Vr> Vs.
(2) Then, an internal stress σ corresponding to the strain ε is generated in the film, and this is the tension P.
(3) At this time, the component force of the tension in the peeling direction is Pr (see FIG. 2), which is balanced with the force f required to peel off the film F from the mill roll R.
That is, the relationship of f = Pr is maintained.
On the other hand, the component Pt in the rotational direction (see FIG. 2) acts in the direction in which the mill roll rotates, but the mill roll R is forcibly rotated by the speeder belt 7, so that it is substantially ineffective. .
[0021]
(4) Therefore, when Vs is increased from the state of (1) and the speed difference ΔV of the peripheral speed is reduced, the strain ε decreases, and the internal stress σ, that is, the tension P decreases.
Even in this state, since the relationship of f = Pr is maintained, the angle θ increases, and the peeling point b on the outer periphery of the mill roll moves counterclockwise in FIG.
When ΔV is further reduced, the limit is reached until the internal stress σ adapted to the strain ε matches the force required to peel the film, that is, σ = f. Since the internal stress σ and the tension P are equivalent, eventually P = Pr.
[0022]
This state is a state of θ = 90 ° in the above equation (2), the direction of the tension P matches the peeling direction of the film, and the peeling point moves to a (see FIG. 3).
In this state, the tension P effectively acts to peel the film 100%, so that the film cannot be rewound with a tension lower than this.
Therefore, for the adhesive film, the speed difference ΔV is set so as to generate an internal stress, that is, a tension so that the peeling direction of the film at the peeling point is perpendicular to the tangential direction of the mill roll. Unwinding theoretically with minimum tension.
[0023]
The above is the case where no shrinkage stress remains in the film wound around the mill roll. When the contraction stress remains, even if ΔV = 0, the tension Po is generated due to the residual internal stress σ ₀ .
Therefore, if the shrinkage stress is left must accelerate the strain ε only ₀ minutes Vs generated for this. However, even in this case, the theory of unwinding with the minimum tension can be applied by setting the speed difference.
[0024]
Incidentally, when the residual stress σ ₀ is larger than the force required for peeling the film, the film from the peeling point to the nip point is contracted by a considerable amount, that is, Vs> V _R, i.e., also appearing cases to increase the speeder belt peripheral speed than the take-up roller circumferential speed.
This is 4 to be actually described below, in the apparatus shown in FIG. 5, when the thickness of 15 [mu] m, a multilayer olefin stretch film having self-adhesive width 500mm unwinding at 600 meters / min, _{V R} to _{V S} Was operated at a speed of 0.8%, which was proved by the fact that the operation according to the above-mentioned theory was able to be performed.
In addition, in order to unwind with a minimum tension that completely complies with the theory, it is strictly θ = 90 °. However, when this is set to θ = 70 °, the tension increases by 6.4%. In most cases, there is no problem with appropriate accuracy.
[0025]
In FIG. 3, between the strain ε and the distance l from the peeling point a where the film is peeled off from the mill roll to the nip point c of the take-off roller, ε = Δl / l.
There is a relationship.
Here, Δl is the amount of elastic displacement (amount of elongation) generated by the speed difference ΔV with respect to the film from point a to point c.
Since ΔV must be kept constant from the beginning to the end of the rewinding of the mill roll and the strain ε must be kept constant in order to keep σ at the tension P equivalent to the minimum tension, the above distance l is set in an actual method / apparatus. Must be kept constant.
In order to make this possible, in the embodiment, while the position of the nip roller is fixed, the center position of the mill roll is continuously moved to the nip roller side in accordance with the reduction in diameter due to unwinding of the mill roll.
[0026]
Next, an apparatus for implementing the present invention will be described.
FIG. 4 is a side view of a main portion of the unwinding machine embodying the present invention, as viewed through a frame. FIG. 5 is a front developed view of FIG.
[0027]
In these figures, a mill roll R is rotatably supported by a chuck 12 at an upper end of a mill roll support arm 11, and a lower end of the mill roll support arm 11 is fixed to a mill roll support arm torque shaft 11 a supported by a machine frame 20.・ It is connected.
The left end of the mill roll support arm torque shaft 11a is connected to the output shaft of the mill roll support arm rotation servomotor 16 via a transmission, and the mill roll support arm rotation angle detector 15 is connected to the right end. Have been.
Accordingly, when the mill roll support arm rotating servo motor 16 is driven, the mill roll support arm 11 rotates about the axis of the torque shaft 11a, so that the center position of the mill roll R is positioned between the axis of the torque shaft 11a and the chuck 12. It can move in an arc shape having a radius equal to the distance between the centers, and the position is constantly detected by the mill roll support arm rotation detector 15 corresponding to the rotation angle of the arm.
[0028]
On the other hand, the mill roll diameter detector 14 provided in the vicinity of the mill roll R is, for example, an ultrasonic type distance measuring device, and the center of the mill roll support arm torque shaft 11a is set so that the ultrasonic wave transmission direction is directed to the center of the mill roll R. The outer diameter of the mill roll R, which changes with the progress of unwinding, is constantly detected by constantly measuring the distance to the outer periphery of the mill roll R.
Although a detailed description is omitted, an appropriate gap δ is fixed between the outer periphery of the mill roll R and the outer periphery of the take-up roller 2 corresponding to an arbitrary diameter of the mill roll R detected by the detector 14. The winding diameter D is input so that the position of the mill roll R corresponding to this is maintained so that the distance l from the peeling point of the film to the nip point of the take-up roller is maintained at a point where the theoretical minimum tension is applied. A support control is performed by a servomotor 16 for turning the mill roll support arm in a manner to match the turning angle detector 15.
[0029]
The relative position of the center position of the mill roll R moved by the above servo mechanism and the take-up roller 2 is such that a straight line passing through the center of the mill roll R having an arbitrary diameter and connecting the nip point of the take-up roller 2 at this time. Is designed so as to be substantially perpendicular to the tangent line of the mill roll at the point of intersection with the outer periphery of the mill roll.
[0030]
The speeder belt 7 can be brought into pressure contact with the outer periphery of the mill roll R by the operation of the pressurized air syringe 9 in the entire range from the maximum diameter of the mill roll to the minimum diameter.
The speeder belt 7 is an endless flat belt in which pulleys 7a and 7b attached to both ends of a pair of right and left speeder belt arms 8 are provided with an appropriate preload, and separates the output of the motor M for driving the take-up roller 2. One of them is driven in a direction in which the film is forcibly unwound from the mill roll R via the continuously variable transmission 10.
[0031]
On the other hand, the film peeling portion is further provided with a film peeling surface position detector 13, and the distance to the film upper surface immediately after the peeling point is fixed to the machine frame 20 by, for example, an ultrasonic distance measuring device. Measure.
This is because the pilot motor PLM of the continuously variable transmission 10 is controlled so that the upper surface position of the film immediately after peeling is kept constant in order to exactly maintain the peel angle θ = 90 ° of the film from the mill roll R which forms the basis of the present invention. To control the speed of the speeder belt 7.
This is effective when the variation in unwinding tension is extremely suppressed or when the force required for peeling varies depending on the location of the mill roll.
[0032]
As described above, the device examples of the present invention have been described. However, the present invention is not limited to the device configuration shown in the above embodiment, and can be easily replaced in light of the technical level in the industry without departing from the purpose. Alternatively, the design can be changed, and these are naturally included in the present invention.
[0033]
For example,
(B) Replace the speeder belt with a positively driven touch roller.
(B) An independent motor is used to drive the take-up roller and the speeder belt, and a speed difference is created by using a draw control method for controlling these speeds.
(C) When the adhesiveness is not weak, the nip roller of the take-off roller is eliminated, and the adhesive surface is directly applied to one release processing roller to take up the film.
(D) The distance l from the film peeling point to the nip point is kept constant by detecting the position of the outer periphery of the mill roll by a control method based on the detection of the roll diameter of the mill roll, and determining the gap δ between this and the outer periphery of the take-up roller. Use a control method that directly keeps it constant.
And so on.
[0034]
Hereinafter, the unwinding mode according to the above configuration will be further described with reference to FIGS. 4 and 5. First, the mill roll R is mounted on the chuck 12, and the position of the mill roll R is appropriately rotated by rotating the mill roll support arm 11. Move to position.
At this time, by setting the gap δ to a predetermined gap, the distance 1 becomes a predetermined size.
Next, the film F is pulled out, nipped by the take-off roller 2, and the speeder belt 7 is pressed and brought into contact with the mill roll R to drive the take-up roller 2 to take out the film F. At this time, the speed difference ΔV from the speeder belt 7 is controlled to be relatively large.
Thus, the state of the peeling point (point b in FIG. 3) of the film F was monitored while gradually increasing the speed of the speeder belt 7, and was approximated to approximately 90 ° even if θ = 90 ° or not exactly 90 °. By the way, stop shifting.
It is preferable and effective to utilize the correction circuit by the film peeling surface position detector 13 as necessary.
[0035]
【The invention's effect】
In the present invention, when unwinding a film having adhesiveness from a mill roll as described above, at a theoretical minimum tension or a slightly higher tension, the film is unwound in a direction perpendicular to the tangent of the mill roll at the mill roll separation point, that is, in the normal direction of the mill roll. In order to keep the unwinding tension at the theoretically minimum tension, the effects of fluctuations in unwinding tension, which had been a concern in the past, on the finishing of the film processing in the next process are eliminated, and wrinkles are generated on the film. This has a remarkable effect of preventing the occurrence of a defective product by preventing a shift in the printing process, thereby preventing the occurrence of defective products and improving the productivity.
[Brief description of the drawings]
FIG. 1 is a diagram showing an outline of a configuration of a conventional unwinder and an outline of unwinding tension control.
FIG. 2 is an explanatory diagram showing a relationship between a rotational force applied to a mill roll at the time of unwinding a film, a peeling force peeled off from the mill roll, and a tension.
FIG. 3 is a skeleton diagram showing the basic concept of the unwinding method of the present invention.
FIG. 4 is a side view showing an outline of an unwinder used for carrying out the present invention.
FIG. 5 is a front development view of FIG. 4 viewed from the right side through a take-off roller.
[Explanation of symbols]
R winding roll (mill roll)
F Film 2 Take-up roller 7 Speeder belt 8 Speeder belt case 9 Speeder belt pressure cylinder 10 Continuously variable transmission 11 Mill roll support arm 12 Chuck 13 Film peeling surface position detector 14 Mill roll diameter detector 15 Mill roll support arm rotation angle detector

Claims (4)

In a method for unwinding a film from a take-up roller by peeling the plastic from a take-up roll formed by winding a thin film of adhesive plastic or the like, the outer peripheral speed of the take-up roll, the peripheral speed of the take-up roller, Adjust the speed difference so that the tension of the film generated by the speed difference from the speed is equal to or slightly larger than the force to peel off the film from the take-up roll, and the unwinding tension is theoretically the lowest value or higher. A film unwinding method characterized by unwinding as a slightly larger value. 2. The film unwinding method according to claim 1, wherein the film is unwound in a direction substantially perpendicular to a tangent of the roll at a peeling point of the take-up roll. A take-up roll rotatably supported by a rotatable take-up roll support arm; a take-up roller that peels off and pulls a film from the take-up roll against the adhesive force; and a maximum diameter of the take-up roll. And a speeder belt that comes into pressure contact with the winding roll in all ranges from the minimum diameter to the minimum diameter, and the winding roll is adjusted by a speed difference between an outer peripheral speed of the winding roll and a peripheral speed of the take-up roller. The speed of the speeder belt is adjusted so that the upper surface position of the film immediately after peeling off from the winding roll is kept constant so that the film peeling angle θ is maintained at approximately 90 °, and the winding changes with the progress of unwinding. According to the outer diameter of the take-up roll, the relative position of the take-up roller and the relative position of the take-up roller is determined by a straight line passing through the center of the take-up roll having an arbitrary diameter and connecting the contact point of the take-up roller. Interchange with the outer circumference of the take-up roll A film unwinding device controlled so as to be substantially perpendicular to a tangent line of a winding roll at a point where the film rolls. 4. The film unwinding device according to claim 3, wherein a distance to the upper surface of the film immediately after peeling is detected by a detector, and the speed of the speeder belt is controlled so as to keep the position constant.

Images