JPH0380703B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention involves winding an ionomer resin film into a paper tube in a sawtooth shape while shifting both edges of an ionomer resin film that is wound after cutting both edges, thereby achieving a good winding shape. The present invention relates to a method for winding an ionomer resin film in which the occurrence of the selvage phenomenon is suppressed.

Ionomer resin films are widely used as packaging materials, either alone or in combination with other films.

When an ionomer resin film for such uses is manufactured in the form of a flat film, it is usually wound up into a paper tube, but the external shape of the wound film, that is, the quality of the winding shape, determines the commercial value of the film. In addition, poor winding impairs the flatness of the film, causes wrinkles and tunneling when used as a laminated film, and also causes whitening due to additive bleed.
Poor roll appearance is called by many names such as bumps, bones, brim, pimples, wave wrinkles, and high ears, and although there is more than one cause for its occurrence, poor winding appearance is thought to be caused by the following causes: .

(i) Uneven thickness of the film (thickness and thinness) (ii) Poor film slippage (iii) Defective slitter (iv) Defective winding machine, inappropriate winding conditions (expander roll application, tatsuchi roll pressure, winding Excess or insufficient tension, etc.) Of these (i), uneven thickness of the film causes bumps, ribs, and bulges, but it cannot be completely eliminated during molding, so the inflation method uses a rotating die, etc. to eliminate so-called uneven thickness of the film. We are dealing with this by dispersing it.

In addition, (ii) if the film is not slippery, bumps, bones, pimples, etc. are likely to appear, and the ears tend to be high, but this can be improved by using additives and changing molding conditions (depending on the application). Although these methods cannot always be used).

Next, the defective slitter in (iii) causes a defective cutting of the edges of the film, and when the film is wound onto a paper cutter, both edges are higher than the center, which is the so-called edge height where the winding diameter is larger. It is the cause of The mechanism of this ear height generation is
To explain in more detail with reference to FIG. 1, if the slitter 1 is applied to the film 2 at a right angle, the slitter cuts well, and the cut surface of the film 2 is at a right angle as shown in FIG. Although no edge height occurs, as the slitter wears down and becomes difficult to cut, the cut surface of the film 2 comes to have a raised portion 3 as shown in B in FIG. With a film that has good slippage, these small defects (raised areas) can be avoided by a slight misalignment with the next overlapping film, but with a film that has poor slippage, these small defects overlap one after another and eventually become noticeable. It develops into a high phenomenon.

The height of the ears is caused by the causes mentioned above, so it is possible to frequently replace the slitter (generally a razor blade) to keep it in a state where it can cut well at all times. Since replacement cannot be performed without once stopping the equipment, frequent replacement is undesirable from the viewpoint of continuous operation, and in reality, replacement is limited to several times a day. Therefore, in order to prevent this edge height, a method has been proposed in which a slitter is applied diagonally (Figure 2) and the film is cut diagonally to absorb the effect of the raised edges, but this method does not allow for flexibility. In the case of such a film, it is not necessarily cut diagonally because the film escapes, and therefore, the edge height cannot be completely prevented.

For this purpose, for example, as described in Japanese Patent Publication No. 50-31585 (hereinafter referred to as known technology),
A technique has been proposed in which a cutter for cutting the ears is periodically moved from side to side.

For example, in the case of polypropylene, polyester, polyamide films, etc., which have relatively good slippage and stickiness, or very soft ethylene-vinyl acetate copolymer films, it is possible to easily form a good winding shape by using known techniques. It is possible to obtain a film. Tenter biaxially stretched film take-up speed (100 to 200 m/min) described in known technology
The poor winding appearance that occurs in this case is a type of uneven thickness called tsuba, which is caused by the large thickness of the ears.
This defect in the winding shape, which is uniform in the circumferential direction and is called brim, can be caused by a wide range of conditions as described in the known art, such as an amplitude of 2 to 20 mm, a length of one period, a film, or a sheet wrapped around the bobbin twice. It is possible to easily obtain a film with a good winding shape by setting the length to be longer than the length. Furthermore, in the case of a very soft film such as an ethylene-vinyl acetate copolymer film, even if an edge height occurs, the film will flow slightly in that area and the edge height will disappear. Films with good winding appearance can be obtained under a wide range of conditions as described.

However, in the case of ionomer resin films, the cause of poor winding is poor cutting due to wear of the slitter due to the hardness of the film, which is unique to ionomer resins, and is called edge height. Moreover, the poor winding appearance is uneven and localized in the circumferential direction, and the degree of this is extremely severe, and such a condition cannot be solved simply by using the conditions described in the known technology.

Furthermore, ionomer resins, especially sodium-based ionomer resin films with excellent transparency, have very poor slippage, and even if a film that has been wound in a poor shape is re-wound, it is difficult to obtain a film with a good shape. It is possible. For this reason, it is necessary to cut both edges of the film extruded into a thin film from an extruder in-line and wind it directly onto a paper tube. The winding speed is determined by the performance of the extruder, resin temperature, cooling conditions, film thickness, etc., but is generally 5 to 50 m/min. When applying the known technology at such a slow winding speed, the winding speed of the winder (initial speed of the bobbin) must be considered as an application condition.

That is, an object of the present invention is to provide a method for winding an ionomer resin film that prevents the occurrence of the above-mentioned winding defects, particularly the edge height.

As mentioned above, the first cause of edge height is due to poor cutting of both edges of the film, but the present invention provides a winding method that allows for poor cutting and does not cause edge height. This is what I am trying to do. The above-mentioned object of the present invention is achieved by so-called staggered winding, in which the overlap of the edges is shifted very slightly and eliminated.

In the case of an ionomer resin film, the present inventor strictly stipulates the deviation of the film per revolution of the paper tube as a function of (i) the amplitude of the cutter and (ii) the film take-up speed for cutting the edges. It has been discovered that only by doing so can a film with a good roll shape be obtained.

According to the present invention, an ionomer resin is melted and plasticized using an extruder equipped with a die at the tip using an inflation method, extruded from a die slit into a thin film, cooled, and then both ears are cut in advance. In a method for winding up an ionomer resin film onto a paper tube at a take-up speed, the ears are cut by a slitter that vibrates from side to side in the width direction with respect to the traveling direction of the film to be wound, and both ears are cut. After shifting both edges of the film and winding it in a sawtooth shape, when cutting the edge part, the widthwise left and right vibrations of the slitter have an amplitude of 1 to 3 mm, and the film begins to be wound onto the paper tube. The condition for the deviation in the width direction in the first winding is (amplitude (mm) x 2 x period (1/min) x paper tube outer circumference (m))}/
{Ionomer resin film take-up speed (m/
min)} is set to 0.01 to 0.3 mm, thereby preventing the occurrence of the ear height phenomenon. Note that this deviation condition refers to deviation during winding due to vibration of the slitter.

The ionomer resin used in the present invention is an ethylene-α,β-unsaturated carboxylic acid copolymer () or an ethylene-α,β-unsaturated carboxylic acid copolymer ().
α,β-unsaturated carboxylic acid ester copolymer () and a portion of its carboxylic acid groups, usually 80%
The following is neutralized with metal ions.

In the present invention, the proportion of ethylene units in the ethylene copolymer component () or () before neutralization is usually about 75 to 99.5 mol%, preferably 88 to 98 mol%, α, β - The proportion of unsaturated carboxylic acid units is usually about 0.5 to 1.5 mol %, preferably 1 to 6 mol %.

Further, the proportion occupied by α,β-unsaturated carboxylic acid ester units is usually 0 to 10 mol%, preferably,
It is 0 to 6 mol%.

Further, among the carboxylic acid groups in the above copolymer () or (), the proportion of carboxylic acid groups neutralized by metal ions (degree of neutralization) is usually 80% or less, preferably 0 to 75%.

The α,β-unsaturated carboxylic acids constituting the above copolymer include acrylic acid, methacrylic acid, ethacrylic acid, maleic acid, fumaric acid, maleic anhydride, and other α,β-unsaturated carboxylic acids having 3 to 8 carbon atoms. The α,β-unsaturated carboxylic acid esters include those having 4 carbon atoms, such as methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, isobutyl acrylate, butyl methacrylate, and dimethyl phthalate. ~8 α,
β-unsaturated carboxylic acid esters are used. Among these, particularly preferred α,β-unsaturated carboxylic acids are acrylic acid and methacrylic acid, and a preferred ester is isobutyl acrylate.

The metal ion that neutralizes the carboxylic acid group of the ethylene copolymer may be a metal ion having a valence of 1 to 3, especially an atom of 1 to 3 in groups A and A in the periodic table of the elements. It is a metal ion ^{that has a valence, specifically, Na +} _,
K ⁺ , L _i ⁺ , C _s ⁺ , A _g ⁺ , H _g ⁺ , C _u ⁺ , B _e ⁺⁺ , M _g ⁺⁺ ,
C _a ⁺⁺ , S _r ⁺⁺ , B _a ⁺⁺ , C _u ⁺⁺ , C _d ⁺⁺ , H _g ⁺⁺ , S _o ⁺⁺ ,
P _b ⁺⁺ , F _e ⁺⁺ , C _p ⁺⁺ , N _i ⁺⁺ , Z _o ⁺⁺ , A _l ⁺⁺⁺ , S _c ⁺⁺⁺ ,
Examples include F _e ⁺⁺⁺ and Y ⁺⁺⁺ . These metal ions may be a mixed component of two or more types. There is no problem even if it is a mixed component with ammonium ions. Among these metal ions, it is most effective to apply the present invention to a sodium type ionomer resin film which has excellent transparency as described above.

Next, when the amplitude of the horizontal vibration of the slitter is less than 1 mm, the period becomes short and the meandering of the film becomes noticeable. If the amplitude is 3 mm or more, the unevenness at the end of the film after winding becomes noticeable, and the ridges at the end of the film become "crushed."

The film deviation (mm) per rotation of the paper tube is given by the following formula. In other words, the film deviation per one rotation of the paper tube (mm) = {the moving distance of the slitter per unit time (mm/
min)}/{Number of paper tube rotations per unit time (1/
min)} = {amplitude (mm) x 2 x period (1/min)} / [{take-up speed (m/min)} / {paper tube outer circumference (m)}] = {amplitude (mm) x 2 x Period (1/min) x paper tube outer circumference (m)}/{take-up speed (m/min)} If the film deviation per revolution of the paper tube is 0.01 mm or less, the deviation of both edges of the film is small, and the edge A height of 0.3 mm or more is unsuitable because it tends to create a meandering shape when the wound film is unrolled.

Therefore, by determining the amplitude and film deviation per rotation as described above, unevenness at the winding end is not noticeable, the end is not crushed by external force, and the film does not meander during winding. First, it is possible to obtain a wound film that has no edge height and is easy to handle.

The tube film formed by the inflation method is folded after passing through a stabilizer pinch roll, and then guided to a winder after passing through several guide rolls. Both edges of the film are removed with a slitter such as a blade, cut vertically or front to back, and then wound up into a paper tube. However, prior to winding, according to the present invention, both edges of the film are cut horizontally in the direction in which the film travels. Cut by a vibrating slitter. A waveform having a periodic length of 1 to 200 m, preferably 2 to 100 m is formed on the edge of the film cut by the slitter 1 in this manner.

An example of the apparatus applied to the present invention will be explained below with reference to FIG. Now, referring to the drawings, it will be easily understood that the present apparatus consists of a slitter section S and its driving section D. Slitter part S
A drive shaft 11 is rotatably supported by bearings 10, 10 so as to be movable in the axial direction, and a pair of adapters 1 are attached to this shaft 11 so that the distance between them can be adjusted freely.
2, 12, and a slitter 1, 1 which is replaceably fixed to this adapter. The drive unit D also includes a motor 13 whose rotational speed can be freely controlled, a gear mechanism 15 that changes the rotation direction of the output shaft 14 of the motor, and at the same time appropriately reduces the speed if necessary, and the output of the gear mechanism 15. It consists of a crank mechanism 18 that converts the rotational motion of the shaft 16 into reciprocating motion of the rod 17, and these are placed on a base 22, and when the rod 17 reciprocates in the direction shown by arrow A, the drive shaft 11 and the slave The slitter 1, 1 attached to it is adapted to move left and right. Note that numerals 19 and 20 in the figure indicate bearings.

In the above device, when the motor 13 is started, the rod 17 is reciprocated in the left-right direction (in the drawing) by the crank mechanism 18. Due to the reciprocating motion of this rod, the drive shaft 11, which is connected to the rod through a joint 21, vibrates from side to side. Therefore, the slitters 1, 1 also vibrate left and right with respect to the traveling direction B of the film 2, and both edges 24 of the film 2 are cut into a waveform corresponding to the vibration of the slitter. Then, it is wound up into a paper tube (not shown). When wound around a paper tube, the ears 24 are shifted and wound in a sawtooth shape, so that the ears do not become high (FIG. 4 shows the rolled up state).

According to the present invention, the edge portion 6 of the film 2 wound around the paper tube 5 has a record-like shape as shown in FIG. , thickness, vibration period and amplitude of the slitter, and the size of the grooves differs between the inside and outside of the winding. However, as a result of conducting numerous tests to find the optimum conditions for preventing the edge height, it was found that the film must have a deviation of 0.01 mm or more per revolution of the paper tube. On the other hand, in this case, strictly speaking, the film is slit in a meandering manner, so the period of the slitter cannot be made extremely small, and the amplitude cannot be made very large (increasing the amplitude will increase film loss. ). Taking these points into consideration, we conducted further studies and found that in order to prevent ear height, the vibration of the slitter should be amplitude = 1 to 3 mm {amplitude (mm) x 2 x period (min) x outer circumference of paper tube (m)} /{Film withdrawal speed (m/min)}=0.01
It was found that it is necessary to satisfy the condition of ~3 mm. By winding the film under these conditions while vibrating the slitter, a paper tube-wound film with no edge height was obtained.

In the apparatus shown in FIG. 3, the amplitude and period are controlled by the eccentricity of the crank mechanism, and the period by the rotational speed of the motor 13. However, the control is not limited to this example. The mechanism could be a cam mechanism or, instead of controlling the rotational speed of the motor, a transmission. It is clear that the illustrated device is an example for shaking a slitter, and is not necessarily required to be the embodiment in order to achieve the object of the present invention.

The effects of the present invention will be explained below with reference to Examples.

Here, we used an ionomer resin (trade name) ``Himilan 1601'' (manufactured by Mitsui Polychemical Co., Ltd.), which has good optical properties and poor slippage and is prone to high-height problems, and the film was molded at a temperature warmer than usual (210°C).

Example 1 A Himilan 1601 inflation film is formed by a known method using a 50 mmφ extruder and a 200 mmφ annular die (thickness 0.1 mm, folding diameter 500 mm).
mm). The film is sent to the winder via pinch rolls and guide rolls, where both edges are cut off by a slitter using a razor blade, and then the film is opened and processed at 450 mm.
A flat film with a width of mm was wound onto a paper tube with a diameter of 3 inches. Film take-up speed is 6m/min
It was hot. At that time, the slitter is set at an amplitude of 2 mm and a period of
A 1000m film was wound while swinging from side to side at 0.15 to 1.5/min. Himilan 1601 film has good optical properties and has very poor slippage, but by vibrating the slitter, films with good winding appearance and no edge height were obtained. When the winding was closely observed, it was found that there was a bulge at the edge of the film when it was cut, which could have caused the edges to be high, but because the edges were wound one after the other with deviations, this defect did not develop and disappeared.

Example 2 As in Example 1, the amplitude of the slitter was set to 3 when winding the Himilan 1601 flat film.
mm, and other conditions were the same. In this case as well, a film with a good winding appearance and no edge height was obtained. However, at a cycle of 1.5/min, it was noticeable that the film was slit in a meandering manner. From this point of view, it has been found that there are limits to making the cycle too fast or the amplitude too large. When the amplitude is large, by slowing down the cycle, a film with good winding appearance and less noticeable meandering can be obtained.

Example 3 As in Example 1, the amplitude of the slitter was set to 1 when winding the Himilan 1601 flat film.
Molding was carried out under the same conditions except that the thickness was set to mm. In this case, at a cycle of 0.15/min, the deviation of the end of the winding was too small to completely prevent the occurrence of selvedge height.
By speeding up the cycle, the occurrence of ear height can be suppressed.
In the case of 1.5/min, a film with good winding appearance was obtained.

Comparative Example 1 A Himilan 1601 flat film was molded under the same conditions as in Example 1, except that the slitter was not vibrated during winding. In this case, the swell at the edge that had once developed grew further as the edges overlapped, and the winding became completely unusable after only about 200 m of winding.

[Brief explanation of drawings]

1A, B and 2 are cross-sectional views showing an example of cutting an ionomer resin film by a slitter, FIG. 3 is a plan view showing an example of an apparatus for carrying out the method according to the present invention, and FIG. FIG. 2 is a cross-sectional view showing a part of the ionomer resin film wound into a paper tube according to the present invention. 1... Slitter, 2... Ionomer resin film, 5... Paper tube, 13... Motor, 18...
crank mechanism.

Claims (1)

[Claims] 1 Melt and plasticize the ionomer resin using an extruder equipped with a die at the tip using the inflation method.
After extruding it into a thin film through a die slit and cooling it,
In a method for winding an ionomer resin film in which both edges are cut in advance and then wound onto a paper tube at a known take-up speed, the ears are removed by a slitter that vibrates left and right in the width direction with respect to the traveling direction of the film being wound. After cutting both ears, the film is wound up in a sawtooth shape with both ears shifted, and when the ears are cut, the widthwise left and right vibrations of the slitter have an amplitude of 1 to 1. 3 mm, and the condition for the deviation in the width direction in the first winding when starting to wind the film onto the paper tube is {amplitude (mm) x 2 x period (1/min) x paper tube outer circumference (m)}/{ Ionomer resin film take-up speed (m/min)} from 0.01 to 0.3
A method for winding an ionomer resin film, characterized in that the selvedge height phenomenon is prevented from occurring.