KR101870454B1 - Film winding method, method for manufacturing film, and method for manufacturing polarizing plate - Google Patents

Abstract

Both the defective black line and the defective winding line are reduced. A winding step of winding a film wound on the take-up shaft onto a take-up shaft; and a slide step of reciprocatingly sliding the take-up shaft in the width direction of the film during the take- The thickness of the film to be wound on the take-up shaft is set to be from a half thickness of the predetermined thickness to a predetermined thickness from the time when the film is wound up to the half thickness of the predetermined thickness until the film is wound up Wherein at least one of a slide speed of the take-up shaft and a rotation speed of the take-up shaft is controlled such that an average value of the period between the winding of the film and the film is increased.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a film winding method, a film production method, and a polarizing plate manufacturing method,

The present invention relates to a film winding method, a film production method and a polarizing plate manufacturing method.

Conventionally, various films such as optical films have been used. As a method for producing these films, for example, there is a method of forming a film having various functions by applying a coating liquid to a long support to form a coating film. In addition, the elongated support body itself can be said to be a kind of film.

Each of these films is wound and stored in the form of a film roll for the first time, and then sent to the next step.

As described above, the winding of the film necessarily occurs, and the film winding step is an indispensable step in the production of the film.

As such a film winding method, Patent Document 1 discloses a film winding method comprising: a straight winding step of winding the film on a core so that the side edges of the film are aligned; and a step of winding the film by winding the side edge in the width direction And winding the film or the winding core periodically in the width direction of the film so that the film or the winding core is periodically shifted in a predetermined range with respect to the winding direction of the film.

This makes it possible to wind the film roll after winding to prevent edge sag and winding deviation from occurring.

Japanese Laid-Open Patent Publication No. 2010-150041

However, in the winding method of the film described in Patent Document 1, it is impossible to solve the defect called blocking or black band which is caused by adhesion of convex portions of the film in the film roll.

SUMMARY OF THE INVENTION In view of the foregoing, it is an object of the present invention to provide a film winding method, a film production method, and a polarizing plate production method capable of simultaneously reducing both defective black band defects (black band defects) and defective winding defects .

The problems of the present invention can be solved by the following respective inventions.

That is, a film winding method of the present invention is a film winding method for winding a film on a winding shaft up to a predetermined thickness, comprising: a winding step of winding a film wound on a winding shaft by winding the winding shaft onto a winding shaft; And a slide step of reciprocally sliding the take-up shaft relative to the film immediately before the film is wound in the width direction of the film. When the thickness of the film wound on the take-up shaft during the reciprocating slide of the take- The average value of the period between the half thickness of the predetermined thickness and the winding of the film to the predetermined thickness is shorter than the average value of the period between the start of winding of the film on the shaft and the winding of the film to half the thickness of the predetermined thickness The relative slide speed, which is the relative slide speed of the take-up shaft relative to the film just before winding, And at least a major one being the control of the take-up shaft speed.

As a result, both of the black band defect and the winding deviation defect can be reduced.

In the film winding method of the present invention, at least one of the relative slide speed and the rotational speed of the take-up shaft is adjusted so that the period is increased until the film is wound up to a predetermined thickness from the start of winding the film on the take- And the like.

As a result, both the black band defect and the winding deviation defect can be further reduced.

The film winding method according to the present invention is a film winding method for winding a film on a winding shaft up to a predetermined thickness, comprising: a winding step of winding a film wound on a winding shaft onto a winding shaft by rotating the winding shaft; And a slide step of reciprocatingly moving the take-up shaft relative to the film immediately before the film is wound in the width direction of the film. In the slide step, when the distance of one half of the distance in which the take- So that the average value of the amplitude between the half thickness of the predetermined thickness and the winding of the film up to the predetermined thickness becomes smaller than the average value of the amplitude between the time when the film is wound up to the half thickness of the predetermined thickness and the winding of the film, The relative slide amount, which is the relative slide amount of the take-up shaft relative to the film immediately before winding, is controlled .

As a result, both of the black band defect and the winding deviation defect can be reduced.

The film winding method of the present invention is characterized in that the relative slide amount is controlled such that the amplitude is decreased until the film is wound up to a predetermined thickness from the start of winding the film on the take-up shaft in the slide step .

As a result, both the black band defect and the winding deviation defect can be further reduced.

In addition, the film production method of the present invention is a film production method for producing a film on which a coated film is formed, comprising the steps of applying a coating liquid to a long substrate, drying the applied coating liquid to form a film on which the coating film is formed, And a step of winding a film having the coated film by any one of the winding methods.

This makes it possible to produce a film in which both defective black bars and defective rolls are reduced.

A polarizing plate manufacturing method according to the present invention is a polarizing plate manufacturing method in which a protective film is adhered to at least one surface of a polarizer, comprising a winding step of winding the protective film into a roll shape by any one of the above- A step of peeling off the protective film to adhere the protective film thus unwound to at least one surface of the polarizer and a cutting step of cutting the polarizer to which the protective film is adhered to a predetermined dimension.

It is possible to reduce both defective black bars and defective winding defects.

1 is a schematic view showing a film production line;
2 is a schematic cross-sectional view of the film wound on the winding shaft in the width direction;
3 is a schematic cross-sectional view of a portion of the wound film.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings. Here, the same reference numerals in the drawings denote the same elements having the same function. Also, in the present specification, when numerical ranges are expressed using " ~ ", numerical values of upper and lower limits indicated by " to "

<Film Production Line>

The film production line according to the present invention will be described with reference to Fig. 1 is a schematic view showing a film production line. As shown in Fig. 1, the film production line 10 related to the present invention mainly comprises a film production apparatus 20 and a winding apparatus 30. Fig.

In FIG. 1, the film production apparatus 20 is described as a simple box in a very simple manner, because there may be various apparatuses as the film production apparatus 20. For example, the film production apparatus 20 may be manufactured by a melt film formation method, a solution film formation method, or the like, or may be an apparatus for producing a film by applying a coating liquid on a support, (Or a support) that is wound by a winding device, but may be an apparatus for producing any film (or support).

Here, the case where the film production apparatus 20 is a slot die type application apparatus will be described as an example. The film manufacturing apparatus 20, which is a slot die coating apparatus, applies a coating liquid to a support body running from a slot to apply coating. The coating liquid supplied on the support forms a thin film on the support, and then dried, whereby the solvent component in the coating liquid evaporates to form a coating film only of the solid component.

Here, on both side ends of the support body, a nulling portion 42 is formed, which is a portion in which microscopic unevenness is formed in advance. In the slot die coating apparatus, a coating liquid is applied also on this knurling portion 42 to form a coating film.

Next, the winding device 30 will be described. The winding device 30 mainly includes a winding shaft 60, a pair of arms 70, a motor (not shown), an oscillate portion 62, and a control portion (not shown) .

The take-up shaft 60 is wound by rotating the film 40 supplied from the film producing apparatus 20 by the guide roller 50. The arm 70 holds the take-up shaft 60 from both sides in the longitudinal direction. The motor rotates the take-up shaft 60. The oscillator portion reciprocally slides the arm 70 in the direction indicated by an arrow 90 (the width direction of the film 40).

The oscillator portion 62 may be constituted by, for example, an oscillator motor 61, an eccentric cam 64, and a spring 66. In this case, when the oscillator motor 61 rotates the eccentric cam 64 and the eccentric cam 64 pushes the arm 70 elastically supported in the direction of the eccentric cam 64 by the spring 66 , The arm 70 is reciprocally slid. In addition, the oscillation portion shown here is merely an example, and any structure may be employed for the structure and method for winding the oscillation while reciprocally sliding.

1 shows a manner in which the oscillation portion 62 reciprocates the arm 70 by reciprocatingly sliding the arm 70. However, the present invention is not limited to this, and the take- May be adopted.

Here, the oscillation portion for reciprocally sliding the take-up shaft is shown, but the present invention is not limited to this, and a method of reciprocally sliding the transport position of the film 40 may be adopted. That is, a method in which the winding shaft 60 reciprocally slides relative to the film 40 immediately before being wound can be adopted. In this case, the oscillation portion reciprocally slides the film 40 immediately before the winding shaft 60 is wound.

Further, in the present invention, it is referred to as an oscillator that reciprocally slides relative to the film immediately before the wind-up shaft is wound. The control unit controls the rotation speed, the oscillation rate, and the oscillation shift amount (reciprocating slide amount) of the take-up shaft 60.

<Film winding method>

A feature of the film winding method of the present invention resides in that it oscillates during winding of the film 40, and is particularly characterized by its oscillation method. Therefore, the oscillation method related to the present invention will be described in more detail with reference to FIG. 2 and FIG. 2 is a schematic cross-sectional view of the film wound on the take-up shaft in the width direction. 3 is a schematic cross-sectional view of a part of the wound film.

Both ends of the cross section in the width direction of the wound film 40 have a zigzag shape as shown in Fig. 2, since the film 40 is rolled while oscillating when the film 40 is wound around the take-up shaft 60. Here, since the width of the film 40 is the same, the left end becomes a curved portion when the right end is a mountain portion and the mountain portion is a left end when the right end is a curved portion in a mountain portion and a valley portion of a zigzag shape do.

As shown in Fig. 2, in the present invention, the apex and apex of the vertex adjacent to the upper and lower sides are referred to as a period, and the width of the apex of the apex of the valley and the apex of the apex The shortest distance between a straight line perpendicular to the rotation axis of the winding shaft 60 and a straight line perpendicular to the winding shaft 60 beyond the apex of the crest adjacent to the curved portion) is referred to as an amplitude.

In other words, the period is the thickness of the film wound around the take-up shaft 60 during one reciprocating slide of the take-up shaft 60 and the amplitude is a distance of half the distance of one reciprocating movement of the take- Not one way says the distance of the slide.

Here, the control of the period is controlled by controlling at least one of the relative slide speed (hereinafter, simply referred to as slide speed) and the winding speed (rotational speed) of the take-up shaft 60 immediately before the winding shaft 60 is wound . Further, the amplitude can be controlled by controlling the relative slide amount (hereinafter, simply referred to as the slide amount) with respect to the film immediately before the winding shaft 60 is wound.

In the present invention, on the side closer to the take-up shaft 60, oscillation is performed so as to be at least one cycle or a larger amplitude or both of them than the far side. When the period is small, it is preferable that the period of the following difference increases from the side closer to the take-up shaft 60 to the outer side. When the amplitude is large, It is preferable that it is small.

As a result, it is possible to reduce both defects called blocking or black bands (in the present invention, defective black bars) and defective winding defects. Here, the defective black band and the defective winding deviation will be described below.

3 (A) and 3 (B) are schematic cross-sectional views of various layers of the film when the film 40 is wound. When the film 40 is wound around the take-up shaft 60, the convex portions 100 in the film 40 may overlap at the same position as shown in Fig. 3A. In this case, the pressure is strongly applied to the convex portion 100 as a result of folding the convex portion 100 several times, resulting in adhesion of the convex portion 100 or elongation due to pressure, resulting in poor product quality. Also, this part looks like a black band from the outside. This is bad black belt.

Therefore, as shown in Fig. 3B, when the film 40 is wound, the projections 100 are shifted by oscillating while being wound, thereby preventing occurrence of defective black bars. Incidentally, since winding is carried out while oscillating, the adhesion is deteriorated, so that defective winding defects tend to occur. The defective winding misalignment refers to defects in which the positions of both side ends of the film roll wound with the film are partially shifted from the initial position after the film roll is wound.

Since the method of reducing these defects and black defects is contradictory to each other, if defects of one side are reduced, defects of the other one are increased and it is difficult to simultaneously reduce both defects. In short, as the winding is more tightly wound, it is possible to prevent defective winding defects. However, defects in black band tend to occur, and when winding is performed without tight contact, defective black bars are not satisfactory but defective winding defects tend to occur.

As a result of intensive studies, the inventors of the present invention have found that both a defective winding defect and a defective black band can be reduced at the same time by changing the oscillation period and amplitude in a specific method.

 <Evaluation>

The film was wound by varying the oscillation rate, and evaluation was made to produce a film roll. In Comparative Examples 1 to 4, film rolls were produced without changing the oscillation period and the amplitude. In Examples 1 to 4, film rolls were produced by varying the period or amplitude.

Occurrence of defective black bars and defective roll defects of the produced film rolls were investigated. The black bars indicate the strength of the sticking marks remaining on the film in four stages of A (none), B (very weak), C (weak) and D (strong). The roll misalignment was examined by moving the film roll in the axial direction of the film roll and stopping the film roll to stop the roll. The generation of the winding deviation is represented by four steps of A (strong), B (slightly strong), C (slightly weak), and D (weak) in the order of difficulty of winding deviation, . Here, the ranges A to C are not defective as the range of good products in all cases. Only D is bad. Table 1 shows the contents of the evaluation and evaluation results, and Table 2 shows the meaning of the evaluation results.

Referring to Table 1, in the cycle "5 → 15" of Example 1, as described in the note, in the average value of oscillation periods on the winding side from the center of the thickness of the film roll, that is, The average value of the oscillation periods of the center between the most near portion and the outermost portion to the most core portion (hereinafter, simply referred to as the center-winding portion) is 5 mm, The average value of the oscillation periods between the middle portion and the outermost portion (hereinafter simply referred to as the mid-outer portion) of the portion closest to the winding and the outermost portion in the thickness direction of the film roll 15 mm and the oscillation period gradually increases from the winding side to the outermost side in the thickness direction of the film roll.

The cycle "2 → 15" in Example 3 has only the numerical values different from each other and has the same meaning as the cycle "5 → 15" in Example 1.

The amplitude of "15 → 5" in Example 4 indicates that the average value of the oscillation amplitudes of the center-core portion is 15 mm, the average value of the oscillation amplitudes of the central-outer portion is 5 mm, Direction, the oscillation amplitude gradually decreases from the winding side to the outermost side.

Further, "5/15" in Example 2 indicates that the oscillation period of the center-winding portion is constant at 5 mm and the oscillation period of the center-outside portion is constant at 15 mm as described in the note .

Likewise, &quot; 15/5 &quot; in Example 5 indicates that the oscillation amplitude of the center-winding portion is constant at 15 mm and the oscillation amplitude at the center-outside portion is constant at 5 mm.

The black band defect is liable to occur as the winding tension is larger, and the poor winding deviation is liable to occur as the winding tension is smaller. In Comparative Examples 1 to 4 in Table 1, when the winding tension is as large as 400 N, the black band defect is D, and when the winding tension is 350 N, it is C, and when the winding tension is 300 N,

On the other hand, in Examples 1 to 4 in which the oscillation period or amplitude is changed, the black band defect is A or C, although the winding tension is large at 500N.

Incidentally, in Comparative Examples 1 to 4, the winding misalignment was D when the winding tension was small, 300N, and C when the winding tension was 350N. On the other hand, in Examples 1 to 4, all A and B are used.

Referring to Example 1, the black band defect rate A and the cold misfeed rate A were both good, and good results were obtained. Comparing the first and second embodiments, the first embodiment has the cold defective deficiency A, while the second defective cold defective is the B defective. Thus, it can be seen that by gradually changing the oscillation period, it is possible to further reduce the defective winding deviation.

Comparing Example 1 and Example 3, in Example 1, the period of oscillation is 5? 15 and the black band defect is A. In contrast, in Example 3, the period is 2? 15 and the black band defect is C. Therefore, it can be seen that the oscillation period of the center-winding portion is 5 mm (about 83 times the thickness of the film) than the 2 mm (about 33 times the film thickness), and the effect of reducing the black band defect is larger.

Comparing Example 1 and Example 4, both of them are black band defect A and cold warp defect A. Therefore, the average value of the oscillation period is changed from 5 mm (center-winding portion) to 15 mm (center-outside portion), or the average value of oscillation amplitude is changed from 15 mm ), It can be seen that both of the defective black band and defective winding deviation can be reduced. From these, it is apparent that good results can be obtained even if both the oscillation period and the amplitude are changed at the same time.

Comparing Example 4 and Example 5, in Example 4, defective winding deficiency is A, while defective winding deficiency is B in Example 5. [ Therefore, it can be seen that by gradually changing the oscillation amplitude, it is possible to further reduce the defective winding deviation.

From the above, it can be seen that by increasing the average value of the oscillation period of the center-outer side than the average value of the oscillation period of the center-winding part, the defective winding defect can be reduced. At this time, it was found that, by gradually increasing the oscillation period from the winding side to the outer side, further defective black band and poor winding deviation can be reduced.

In addition, it was found that by reducing the average value of the oscillation amplitudes of the central-outer side compared with the average value of the oscillation amplitudes of the center-winding portion, the defective winding defects can be reduced. At this time, it was found that, by gradually reducing the oscillation amplitude toward the outer side from the winding side, it is possible to further reduce the black band defect and the winding deviation defect.

Further, it has been found by the inventors of the present invention that the average oscillation period of the center-winding portion is 40 to 250 times the film thickness and the average oscillation period of the center-outside portion is preferably 80 to 1000 times the film thickness. At this time, it was also found that the average oscillation period of the center-outer portion is preferably 3% or more larger than the average oscillation period of the center-winding portion. At this time, it was also found that it is most preferable that the oscillation period gradually changes from the winding side to the outside side.

Similarly, with respect to the average oscillation amplitude, the average oscillation amplitude of the center-winding portion is 1.5 to 4 times the width of the film formed on the nulling or the nulling width of the film end, and the average oscillation amplitude of the center- It is preferable that the width is 0.01 to 2 times the width of the film formed on the ring width or knurling. At this time, it was also found that the average oscillation amplitude in the center-outer side was more preferably 3% or less smaller than the average oscillation amplitude in the center-winding. At this time, it was also found that it is most preferable that the oscillation period gradually changes from the winding side to the outside.

&Lt; Polarizing plate production method >

Next, a method for producing a polarizing plate using the film winding method according to the present invention will be described. Polarizer means a protective film laminated on one side or both sides of a polarizer.

Examples of the polarizer include dichroic materials such as iodine and dichroic dyes, and the like, to a hydrophilic polymer film such as a polyvinyl alcohol film, a partially porous polyvinyl alcohol film, or an ethylene / vinyl acetate copolymer system partially saponified film A polyvinyl alcohol-based dehydrated product, a polyvinyl chloride dehydrochloric acid-treated product, and the like. Among them, a polyvinyl alcohol film and a polarizer made of a dichroic material such as iodine are preferable.

The material forming the protective film laminated on one side or both sides of the polarizer is preferably excellent in transparency, mechanical strength, thermal stability, moisture barrier property, isotropy and the like. For example, a polyester polymer such as polyethylene terephthalate or polyethylene naphthalate, a cellulose polymer such as diacetylcellulose or triacetylcellulose, an acrylic polymer such as polymethyl methacrylate, a polystyrene or an acrylonitrile styrene copolymer (AS resin), and polycarbonate-based polymers. Further, it is also possible to use a polyolefin-based polymer such as polyethylene, polypropylene, a cycloolefin-based or norbornene-based structure, an ethylene-propylene copolymer, an amide-based polymer such as nylon or aromatic polyamide, Based polymer, a polyether sulfone-based polymer, a polyetheretherketone-based polymer, a polyphenylene sulfide-based polymer, a vinyl alcohol-based polymer, a vinylidene chloride-based polymer, a vinyl butyral-based polymer, an allylate- An epoxy-based polymer, or a blend of the above-mentioned polymer may be mentioned as an example of the polymer forming the protective film.

As the material for forming the protective film, those exemplified above can be conceivable. In consideration of polarization characteristics and durability, a cellulose-based polymer such as TAC (triacetyl cellulose) is preferable, and a TAC film is particularly preferable.

Further, a hard coat layer may be formed on the surface of the protective film on which the polarizer is not adhered, or a treatment for the purpose of anti-reflection treatment, diffusion or anti-glare may be performed.

A protective film is produced in the above-described film production line, and the protective film is wound in a roll form using the winding method of the present invention.

Next, the protective film wound in a roll form and the polarizer wound in a roll form are released, respectively, but a protective film is bonded to one surface or both surfaces of the polarizer. When a protective film is adhered to both surfaces of a polarizer, a protective film can be simultaneously adhered to both surfaces of the polarizer by using two rolls of a roll-wound protective film.

A water-based adhesive or the like can be used for bonding the polarizer and the protective film. Examples of the water-based adhesive include an isocyanate adhesive, a polyvinyl alcohol adhesive, a gelatin adhesive, a vinyl-based latex, a water-based polyurethane, and a water-based polyester.

Next, the polarizer to which the protective film is adhered is cut to a predetermined size. Thus, a polarizing plate cut to a predetermined size can be produced.

10 ... Film manufacturing line, 20 ... Film manufacturing equipment, 30 ... Winding device, 40 ... Film, 42 ... Null ring part, 50 ... Guide roller, 60 ... Winding shaft, 61 ... Oscillator motor, 62 ... Oscillator section, 64 ... Eccentric cam, 66 ... Spring, 70 ... Arm, 100 ... Convex portion

Claims (6)

A film winding method for winding a film on a winding shaft up to a predetermined thickness,
A winding step of winding the film wound on the take-up shaft onto the take-up shaft by rotating the take-up shaft;
And a slide step of reciprocally sliding the take-up shaft relative to the film immediately before the winding in the width direction of the film during the winding step,
The film winding apparatus according to any one of claims 1 to 3, wherein, in the sliding step, when the thickness of the film wound on the take-up shaft during the one reciprocating slide of the take-up shaft is taken as a period, Wherein the average value of the period between the half of the predetermined thickness and the winding of the film to the predetermined thickness is larger than the average value of the period between the winding of the film Wherein at least one of a relative slide speed as a slide speed and a rotational speed of the take-up shaft is controlled. The method according to claim 1,
Wherein at least one of the relative slide speed and the rotation speed of the take-up shaft is controlled such that the period is increased until the film is wound up to the predetermined thickness from the start of winding the film on the take- Winding method. A film winding method for winding a film on a winding shaft up to a predetermined thickness,
A winding step of winding the film wound on the take-up shaft onto the take-up shaft by rotating the take-up shaft;
And a slide step of reciprocally sliding the take-up shaft relative to the film immediately before being wound, in the width direction of the film during the winding step,
Wherein a distance between a half of the distance at which the winding shaft is reciprocated in the slide step is set as an amplitude and a time at which the film is wound up to a half thickness of the predetermined thickness Which is the relative slide amount of the winding shaft with respect to the film immediately before winding so that the average value of the amplitude between the half thickness of the predetermined thickness and the winding of the film up to the predetermined thickness becomes smaller than the average value of the amplitude of the winding Wherein the slide amount is controlled. The method of claim 3,
Wherein the relative slide amount is controlled such that the amplitude is reduced until the film is wound up to the predetermined thickness from the time when the film is wound around the winding shaft to the predetermined thickness. A film production method for producing a film having a coated film,
Applying a coating liquid to the long substrate,
Drying the applied coating liquid to form a coated film,
A film production method comprising winding a film on which the coating film is formed by the film winding method according to any one of claims 1 to 4. A method for producing a polarizing plate having a protective film adhered to at least one surface of a polarizer,
A film winding method according to any one of claims 1 to 4, comprising a winding step of winding the protective film into a roll shape,
A step of peeling off the wound protective film to adhere the protective film to at least one surface of the polarizer,
And cutting the polarizer to which the protective film is adhered to a predetermined dimension.

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