CN102909863A

CN102909863A - Method of manufacturing polarizing film

Info

Publication number: CN102909863A
Application number: CN2012102761807A
Authority: CN
Inventors: 松尾直之; 高见伸行; 下田麻由
Original assignee: Nitto Denko Corp
Current assignee: Nitto Denko Corp
Priority date: 2011-08-05
Filing date: 2012-08-03
Publication date: 2013-02-06
Anticipated expiration: 2032-08-03
Also published as: JP2013037132A; CN102909863B; TWI551894B; KR101889560B1; TW201307907A; KR20130016108A; JP5767891B2

Abstract

The present invention provides a method of manufacturing polarizing film, which has a first step of sequentially stretching a plurality of polyvinyl alcohol-based resin film; and a second step of connecting the foregone terminal part of the first polyvinyl alcohol-based resin film and the following front part of the second polyvinyl alcohol-based resin film by welding. In the second step, the terminal part is coincident with the front part, and the initial elasticity modulus of the engaging part is more than 65% and less than 100% with respect to the initial modulus of non-engaging parts.

Description

The manufacture method of polarizing film

Technical field

The present invention relates to the limit makes banded polyvinyl alcohol resin film move that the limit stretches along its length on its mobile route and the manufacture method of making the polarizing film of polarizing film.

Background technology

All the time, utilize the optical thin film that comprises polarizing film etc. in the image display device such as liquid crystal indicator.

Manufacture method as this polarizing film, adopt following method: polyvinyl alcohol resin film (reel film) is sent from the former winding up roller that banded polyvinyl alcohol resin (PVA) the film roll coiled roller shape as reel forms in the limit, stipulate the mobile route of this reel film, the limit is by the device that possesses guiding a plurality of rollers of this reel film and various liquid and bathe and make its stretching.For example, adopt following method: the reel film is moved along its length direction, be immersed in continuously in swelling bath, the dye bath, afterwards, 2 places to applying tension force therebetween, implement aforementioned stretching with aforementioned roller clamping reel film in front and back.

But in the manufacture method of this polarizing film, when exchanging former winding up roller, it is upper and be arranged in the said apparatus all to need again new reel film roll to be hung over roller etc. at every turn, and this bothers and loses time very much.Therefore, carried out following operation: the leading section that engages the reel film that stretches out from ensuing former winding up roller at the terminal part of the reel film that gets ahead makes its connection, and these reel films are supplied in the said apparatus successively continuously.

As this joint method, adopt: utilize the bonding joint method of adhesive tape, bonding agent etc., utilize the stitching joint method of rivet, line etc., or utilize the heating and melting joint method etc. of heat sealing machine etc. all the time.

But there is respectively following problems in aforesaid method.

Utilize the problem in the bonding joint of adhesive tape, bonding agent etc.

In making the thin film dipped operation in swelling bath, dye bath etc. of reel, therefore the stripping in liquid because the one-tenth of bonding agent grades can become the main cause of polluting liquid, adhering to foreign matter at goods.Moreover, also have following worry: bonding agent is dissolved in the liquid or because of the composition swelling of liquid, thereby bond strength reduces, in stretching process before reaching desirable stretching ratio the connecting portion fracture.

Utilize the problem in engaging such as the stitching of rivet, line etc.

In the method, wear for the hole by rivet, line at the reel film, therefore, when connecting portion is applied tension force, exist take the worry of aforementioned apertures as the starting point fracture.

When reducing hole count for fear of the generation of this situation and guaranteeing that the interval in hole is wider, exist when applying tension force, to produce easily gauffer and the uneven worry that stretches occurs.

Utilize the problem in engaging such as the heating and melting of heat sealing machine etc.

As can seeking to solve above-mentioned bonding joint, sew up the joint method of the problem in engaging, the method for utilizing heat sealing machine to engage shown in the known following

patent documentation

1,2 and 3 etc.

The method is compared with bonding joint, and the worry of polluting liquid is less, and does not need as sewing up joint the hole to be set.

But heat sealing machine has welding area and the heat modification that is subject to during on every side because of welding, compare the tendency of the state that becomes curing with common part.

Therefore, if this welding area of clamping applies tension force when stretching, then have following worry: concentrate on easily the position of this curing and common state the position boundary member and produce stress, before all reaching desirable stretching ratio, should be stretched terrifically in the zone.

Therefore, when wish is implemented the stretching of high stretching ratio, exist the reel film in the worry of connecting portion fracture.

The prior art document

Patent documentation

Patent documentation 1: TOHKEMY 2007-171897 communique

Patent documentation 2: TOHKEMY 2010-8509 communique

Patent documentation 3: TOHKEMY 2004-160665 communique

Summary of the invention

The problem that invention will solve

In order to give polarizing film high polarisation function, usually require to apply the stretching more than 5.25 times.But, when the reel film that utilizes aforesaid method of attachment in the past to connect to be formed by polyvinyl alcohol resin, exist connecting portion can not tolerate tensile load more than 5.25 times and the worry of fracture.Therefore, thus made and will become by the stretching ratio during the connecting portion 5.25 times of less thaies and avoid the countermeasure that ruptures.

But when selecting aforesaid countermeasures, the stretching ratio before and after the connecting portion does not become desirable multiplying power (more than 5.25 times), therefore, can't use as goods, can cause waste of material.

Therefore, to the reel film that is formed by polyvinyl alcohol resin that connects, the limit take with respect to this reel film as the stretching ratio more than 5.25 times apply the stretching limit carry continuously be relatively the difficulty, and, also do not propose to carry out so far the method for attachment of this stretching and conveying.

That is, there is the problem be difficult to effectively make polarizing film with high polarisation function and so in the manufacture method of existing polarizing film.

In view of the above problems, the object of the invention is to, a kind of manufacture method that can effectively make the polarizing film of the polarizing film with high polarisation function is provided.

For the scheme of dealing with problems

What be used for addressing the above problem the invention is characterized in, makes continuously the method for polarizing film for using a plurality of banded polyvinyl alcohol resin films,

The method has following operation:

The 1st operation is sent into mobile route and along its length stretching this mobile route from front successively with each polyvinyl alcohol resin film; With

The 2nd operation overlaps the terminal part of the first polyvinyl alcohol resin film that gets ahead and the leading section of ensuing the second polyvinyl alcohol resin film, by welding they engaged to connect,

In aforementioned the 2nd operation, engage, so that the initial elastic modulus at junction surface is more than 65% below 100% with respect to the initial elastic modulus of disengaged section.

Here, among the present invention, the initial elastic modulus at junction surface refers to, cut (the length direction length 1.5mm of above-mentioned polyvinyl alcohol resin film) * (the width length 20mm of the above-mentioned polyvinyl alcohol resin film) zone in the junction surface, to the junction surface section as the junction surface that cuts, the stress 1N/mm in the load-deformation curve that obtains under the condition of initial chuck spacing 10mm, draw speed 0.1mm/min, carrying out tension test under 20 ℃ of environment of room temperature ²Under tangent slope.

In addition, the initial elastic modulus of disengaged section refers to, cut (above-mentioned length direction length 3.0mm) * (the above-mentioned width length 20mm) zone in disengaged, to disengaged section of the disengaged section of conduct that cuts, the stress 1N/mm in the load-deformation curve that obtains under the condition of initial chuck spacing 10mm, draw speed 0.1mm/min, carrying out tension test under 20 ℃ of environment of room temperature ²Under tangent slope.

Need to prove, during the not enough 1.5mm of junction surface width (above-mentioned length direction length), cut the length that to take as the above-mentioned length direction length at junction surface, cut 2 times length of this length as the above-mentioned length direction length of disengaged section, by similarly estimating with above-mentioned, obtain the initial elastic modulus of above-mentioned junction surface and disengaged section.

Utilize above-mentioned manufacture method, can with the terminal part of the first banded polyvinyl alcohol resin film that gets ahead in the banded polyvinyl alcohol resin film more than 2 that stretches with it the leading section of the second banded polyvinyl alcohol resin film of being connected and engage so that satisfy above-mentioned relation as the initial elastic modulus at the junction surface of weld portion with respect to the initial elastic modulus of disengaged section.Thus, can make the hardness of the hardness at junction surface and disengaged section very approaching, therefore, the stress that causes because of stretching in the time of can relaxing along above-mentioned length direction stretching junction surface concentrates on the boundary member of junction surface and disengaged section.Therefore, even also can avoid above-mentioned border fracture with for example stretching of the stretching ratio more than 5.25 times.Thus, though at the junction surface by the time do not change stretching condition and can stretch continuously yet.Therefore, can obtain the effect that operating efficiency improves, productivity ratio improves, yield rate improves and waste of material reduces.

In addition, the manufacture method of polarizing film of the present invention preferably by utilize laser welding with aforementioned terminal part be connected leading section and engage and to connect to implement aforementioned the 2nd operation.

Thus, as described below.That is, as heat-sealing etc. like that through-thickness terminal part and leading section are carried out in the situation of whole heating, become larger as the zone that curing occurs in the junction surface of weld portion.Relative therewith, in laser welding, can be only to the interface of terminal part and leading section, with and near zone carry out local heat and welding, therefore, can make occur in the junction surface to solidify regional smaller.Thus, apply when stretching, form the junction surface by laser welding and compare with the situation that forms the junction surface by heat-sealing etc., the easier hardness at junction surface that makes is approaching with the hardness of disengaged section.Therefore, the initial elastic modulus that is bonded into easily the junction surface is more than 65% below 100% with respect to the initial elastic modulus of disengaged section.

In addition, the manufacture method of polarizing film of the present invention is preferably implemented the aforementioned laser welding at the interface portion configuration light absorber of aforementioned terminal part and aforementioned leading section.

Thus, the light absorption of the laser of the interface portion of leading section and terminal part increases, and therefore can more effectively make the two welding.

In addition, the manufacture method of polarizing film of the present invention is preferably implemented the aforementioned laser welding with the following infrared laser of the above 11000nm of wavelength 800nm.

Thus, can make the more effectively melting of above-mentioned end section and leading section, therefore, can more effectively first and second polyvinyl alcohol resin film be engaged and connect.

In addition, preferred aforementioned the first polyvinyl alcohol resin film of the manufacture method of polarizing film of the present invention and aforementioned the second polyvinyl alcohol resin film separately disengaged and the stretching ratio at junction surface are more than 5.25 times.

Thus, can improve quality as polarizing film.

The effect of invention

As mentioned above, according to the present invention, can effectively make the polarizing film with high polarisation function.

Description of drawings

Fig. 1 is the schematic perspective view of the device that uses in the manufacture method of polarizing film of an embodiment of expression.

Fig. 2 is the schematic perspective view of situation that expression connects the reel film and be supplied to the manufacturing installation of polarizing film.

Fig. 3 is that expression is for the schematic elevational view of the mechanism of the major part of the jockey that connects the reel film.

Fig. 4 is the figure of expression junction surface and disengaged section, and Fig. 4 (a) is schematic side elevational view, and Fig. 4 (b) is schematic plan.

Fig. 5 is the figure of the section of expression junction surface and disengaged section, and (a) of Fig. 5 is the schematic plan at junction surface, the schematic plan at (b) right and wrong junction surface of Fig. 5.

Fig. 6 is before expression stretches and the junction surface section when stretching or the schematic plan of disengaged section.

Fig. 7 is expression load-deformation curve, and stress 1N/mm ²Under the figure of an example of tangent line.

Fig. 8 is the chart of ratio of the initial elastic modulus of expression embodiment and comparative example.

Description of reference numerals

1: reel film (banded polyvinyl alcohol resin film), 1a: terminal part, 1b: leading section, 4d: stretch bath, 9: roller

The specific embodiment

Below embodiments of the present invention are described.

At first, describe with reference to the preferred stretching device of accompanying drawing to the manufacture method of polarizing film that be used for to implement present embodiment.

The stretching device of present embodiment possesses: be wound into the roller shape and the former winding up roller that obtains is sent the reel membrane supplying section 3 of aforementioned reel film 1 from banded polyvinyl alcohol resin film (below be also referred to as " reel film " or referred to as " film "); Be used for the reel film 1 of sending is immersed in a plurality of dipping baths 4 of the liquid of regulation; Stipulate a plurality of rollers 9 of the mobile route of reel film 1 by the mode in this dipping bath 4 with aforementioned reel film 1; The extension section of stretching reel film 1 in this mobile route; And will in a plurality of dipping baths 4, flood and carry out the film that stretches and batch polarizing film reeling end 10 into the roller shape as polarizing film.

Fig. 1, Fig. 2 are the schematic perspective view of a mode of the preferred stretching device of expression.

As shown in Figure 1, as a plurality of dipping baths 4, in stretching device, begin to possess successively the swelling that has be used to the swelling solution that makes the polyvinyl alcohol resin films swell from the moving direction upstream side of film and bathe 4a; Have for swelling the dye bath 4b of dyeing liquor of dyeing films; Have the crosslinked bath 4c be used to the crosslinked crosslinking agent liquid of the strand that makes the resin that consists of film; Be used for the stretch bath 4d at the bath stretch film; And have for cleaning these 5 kinds of dipping baths 4 of cleaner bath 4f by the cleaning fluid of the film of this stretch bath 4d.

In addition, in the stretching device of this mode, the upstream side of the downstream of the cleaner bath 4f in the mobile route of film and reeling end 10 possesses the drying device 11 that makes film drying, particularly is drying oven.

And then; in the stretching device of this mode, also possess: the film for laminating 12 such as surface protective film (such as cellulose triacetate film, cyclic olefin polymer film) that will be wound into the roller shape be configured in respectively with aforementioned drying device 11 carried out dry film the two sides side, be used for the stacked laminator at the stacked film for laminating 12 in the two sides of dried film.

As aforementioned extension section, adopt so-called roller extension section 9a.That is, adopt following formation: in aforementioned mobile route, the paired roll 9a that the many groups of configuration consist of with middle clamping film and the mode sent to the moving direction downstream, and make the peripheral speed of group in moving direction downstream higher than upstream side.

And then this stretching device consists of in mode that can continuously elongated 2 above reel films, and it possesses the device that is connected with the second reel film for the terminal part with the first reel film of these 2 above reel films.Namely, in this stretching device, as shown in Figure 2, possess: before being used for before the terminal part 1a of the first reel film 1 that gets ahead is by the mobile route of having stipulated, being specially by dipping bath 4, the jockey (not shown among Fig. 2) that the terminal part 1a of this first reel film 1 and this reel film 1 and then leading section 1b joint by the new reel film in the mobile route (the second reel film) is connected by laser welding.

Need to prove, among Fig. 2, represent the part (weld portion) that engages by Ear Mucosa Treated by He Ne Laser Irradiation with the part 30 of blacking.

Then, with reference to Fig. 3 preferred jockey is described.

The schematic pie graph of this Fig. 3 jockey that to be expression be bonded with each other the reel film to connect by laser welding.

Fig. 3 represents to observe towards TD direction (width) from its side the front view of the jockey of the reel film that connects.

As shown in Figure 3, aforementioned jockey has: the platform 40 with smooth upper surface portion; Be configured in the pressure-producing part 50 that can above-below direction disposes movably of the top of this platform 40; Be configured in the LASER Light Source (not shown) of the top of this pressure-producing part 50.In addition, as the formation of getting off: the terminal part 1a of the first reel film 1 that gets ahead and the leading section 1b of coupled the second new reel film 1 are coincided with the upper and lower at aforementioned platform 40, the limit adds flanging with 50 pairs of these intersection of aforementioned pressure-producing part and states LASER Light Source irradiation laser R in the past, makes interface portion heating and melting and the welding of aforementioned terminal part 1a and aforementioned leading section 1b.And then aforementioned pressure-producing part 50 is made of the transparent parts of the transmittance excellence of laser R.

Need to prove, for the light absorption of the laser R of the interface portion that can improve aforementioned terminal part 1a and aforementioned leading section 1b, more effectively implement welding, can also possess in the aforementioned jockey: in aforementioned interface portion, want aforementioned terminal part 1a that face connects or any the surface (or two sides) among the aforementioned leading section 1b to be coated with in advance the apparatus for coating of light absorber.

Need to prove, as light absorber used herein, so long as the material of absorbing laser R and generation heat just is not particularly limited, can use carbon black, pigment, dyestuff, water etc.

Be that absorbent, naphthalene phthalocyanine are that absorbent, polymethine are that absorbent, diphenyl-methane are that absorbent, triphenylmenthane are that absorbent, quinone are that absorbent, azo are absorbent, Diimmonium salt etc. such as using phthalocyanine.

In addition, when using the LASER Light Source of the laser R send the wavelength with 800nm～1200nm, for example can use that U.S. Gentex company makes with the commercially available light absorber of trade name " Clearweld(registration mark) ".

These absorbents can be with dilutions such as organic solvents, with aforementioned apparatus for coating coating.As this apparatus for coating, such as adopting: general apparatus for coating such as distributor, ink-jet printer, screen printer, 2 fluid-types, 1 fluid-type or ultrasonic type sprayer, printer, coating machines.

The kind of the LASER Light Source that utilizes in this jockey in addition, also is not particularly limited.Preferably, employed laser is that performance is absorbed by the light absorber that is coated with one or two reel film surfaces in the interface of waiting the new and old reel film in the part that is configured in new and old reel film coincidence, the laser of the effect of heating, and has the high wavelength of absorption sensitivity of employed light absorber.

Particularly, as the kind of laser, can list Solid State Laser, the CO such as semiconductor laser, fibre laser, femtosecond laser, picosecond laser, YAG laser of the wavelength with visible region or infrared spectral range ₂The gas lasers such as laser.

Wherein, particularly preferably obtain easily semiconductor laser, the fibre laser of the laser beam of homogeneous in cheapness and the face.

In addition, for fear of the decomposition of reel film and in order to promote melting, drop into high-octane pulse laser with moment and compare, more preferably the CW laser of continuous wave.

The power of laser (power), beam diameter and shape, irradiation number of times and sweep speed etc. get final product according to the different suitably optimizations as thermal characteristics such as the optical characteristics such as the reel film of object and the absorptivity of light absorber, the fusing point that consists of the polymer of reel film, glass transition temperature (Tg) etc.In order effectively to be made the polyvinyl alcohol resin liquidation by the part of Ear Mucosa Treated by He Ne Laser Irradiation and firmly to be engaged, as the power density of the laser that shines, preferably at 200W/cm ²～10,000W/cm ²Scope in, more preferably at 300W/cm ²～5,000W/cm ²Scope in, further preferably at 1,000W/cm ²～3,000W/cm ²Scope in.

In addition, as long as the initial elastic modulus that this laser irradiation condition can carry out the junction surface as described later is the joint below 100% more than 65% with respect to the initial elastic modulus of disengaged section, just be not particularly limited.

In addition, the LASER Light Source that utilizes in the jockey preferably can shine at the interface of new and old reel film the LASER Light Source of laser with the spot diameter (irradiating width) of prescribed level.

As this irradiation spot diameter (irradiating width), preferably be that 1/10 of new and old reel film overlap width is above below 3 times under the power that satisfies aforementioned irradiation laser power density.

1/10 o'clock of not enough overlap width, the not junction surface of coincidence part is large, has the worry of agitating, hinder good transporting when carrying after engaging.

In addition, when surpassing 3 times width irradiation laser, although on engaging and not impact of tensile properties, be not preferred from the viewpoint of energy utilization efficiency.

Be preferably the 1/5 above below 2 times of overlap width.

Need to prove, when the overlap width of new and old reel film diminishes, existence is difficult to the worry that repeatable accuracy overlaps the reel film of the large width of configuration well, when the overlap width of new and old reel film becomes large, has the worry that engaging zones does not become large, film is agitated when engaging rear the conveying.Therefore, the overlap width of this new and old reel film for example can suitably be set from the viewpoint.

In addition, the beam shape of laser can be circle, considers also can be wire from the viewpoint that obtains higher power density.

Need to prove, as the cumulative exposure of laser, preferably at 5J/cm ²～400J/cm ²Scope in, more preferably at 10J/cm ²～300J/cm ²Scope in, particularly preferably in 30J/cm ²～150J/cm ²Scope in.

Therefore, preferably in jockey, adopt the LASER Light Source that can satisfy these conditions.

As at the pressure-producing part 50 that on the platform the aforementioned new and old reel film (the leading section 1b of the terminal part 1a of old reel film and new reel film) that overlaps is pressurizeed, can use the glass member made to employed laser display high transparent under the irradiation of such laser.

Add Compressive Strength during as Ear Mucosa Treated by He Ne Laser Irradiation, preferably at 0.5～100kgf/cm ²Scope in, more preferably at 10～70kgf/cm ²Scope in.

Therefore, the pressure-producing part 50 that preferably adopts as aforementioned jockey, so long as can be with the parts of such intensity pressurization, the shape of described glass component just be not particularly limited, and for example can use flat board, cylinder, spherical glass component.

The thickness of glass component is not particularly limited, and when excessively thin, because distortion can't be carried out good pressurization, when blocked up, the utilization ratio of laser reduces.Therefore, the thickness of the direction of laser-transmitting is preferably the above and not enough 30mm of 3mm, more preferably above the and not enough 20mm of 5mm.

As the material of pressure-producing part 50, such as listing: quartz glass, alkali-free glass, TEMPAX, Pyrex(registration mark), Vycor, D263, OA 10, AF45, Zerodur etc.

In order to improve the utilization ratio of laser R, the glass member made that utilizes as pressure-producing part 50 preferably has high transparent to employed optical maser wavelength, preferably has the light transmittance more than 50%, more preferably has the light transmittance more than 70%.

Need to prove, when using aforesaid glass member made to consist of pressure-producing part 50, also can form in the part of joining with the polyvinyl alcohol resin film and compare the more excellent cushion of resiliency with aforementioned glass member made, larger area being pressurizeed more equably and carries out good joint in whole zone.

That is, also can adopt the pressure-producing part 50 that possesses the good rubber slab of light transmission, has the transparent resin plate etc. of resiliency.The pressure-producing part 50 that the front face side that for example, can adopt rear side to be consisted of, joined with the polyvinyl alcohol resin film by the glass member made is made of transparent rubber plate plate.

The formation of aforementioned cushion can be used the resin materials such as the material such as the rubber series such as silicon rubber, polyurethane rubber, polyethylene.

The thickness of this cushion is preferably the above and not enough 5mm of 50 μ m, more preferably above the and not enough 3mm of 1mm.

During less than 50 μ m, lack resiliency, be 5mm when above, have following worry: according to this cushion, lasing absorption, scattering reduce the energy of the laser of the contact interface section that arrives aforementioned terminal part 1a and leading section 1b.

This cushion preferably has light transmittance more than 30% to employed optical maser wavelength, more preferably more than 50%.

In addition, also can will be configured in the upper surface of platform 40 with the same cushion of this cushion.When being configured on the platform 40, be used to form the material of cushion optical characteristics, be that light transmission is not particularly limited, on the basis of above-mentioned silicon rubber etc., can also use such as Merlon, PETG, norbornene resin, cyclic olefin polymer, polymethyl methacrylate, polyimides, Triafol T etc.

In the manufacture method of the polarizing film of present embodiment, preferably consist of aforementioned jockey in the mode that can implement laser welding along the intersection of the new and old reel film that overlaps, form the weld portion of wire.For example, preferably possess: be used for making by collector lens optically focused becoming the spot beam of desirable beam diameter along the mechanism of intersection scanning; By using the opticses such as cylindrical lens, diffraction optical element to be shaped as the laser beam of wire and shining the mechanism of the coincidence part of reel film; And by the mechanism etc. that disposes a plurality of LASER Light Sources along coincidence part and thereby the simultaneously disposable melting of irradiation adds thermal bonding in the situation of not strafing.

Need to prove, although be not described in detail here, can adopt in the above-mentioned jockey general laser welding device with and the peripheral plane device in the various mechanisms that utilize.

Below, the method that utilization is possessed the stretching device manufacturing polarizing film of such jockey describes.

In the manufacture method of the polarizing film of present embodiment, possess following the 1st operation and the 2nd operation and make continuously polarizing film: the 1st operation, use a plurality of banded polyvinyl alcohol resin films, each polyvinyl alcohol resin film is sent into mobile route from front, in this mobile route, stretch along its length; The 2nd operation overlaps the terminal part of the first polyvinyl alcohol resin film of getting ahead and the leading section of ensuing the second polyvinyl alcohol resin film, by welding their is engaged and connects.

In addition, in aforementioned the 2nd operation, engage as the mode below 100% more than 65% with respect to the initial elastic modulus of disengaged section take the initial elastic modulus at junction surface.

Particularly, in the manufacture method of the polarizing film of present embodiment, as aforementioned the 1st operation, implement to make the aforementioned reel thin film dippedly bathe the swelling operation that makes its swelling among the 4a in swelling, make swelling the thin film dipped dyeing process that in dye bath 4b, dyes, make dyeed thin film dipped in crosslinked bath 4c, make the crosslinked crosslinked operation of the strand of the resin that consists of film and will this crosslinked operation after film at the stretching process of stretch bath 4d in-draw.

That is, in the manufacture method of the polarizing film of present embodiment, bathe 4a in swelling and in each of stretch bath 4d bathed, implement to stretch, so that finally be the target stretching ratio.

In addition; in the manufacture method of the polarizing film of present embodiment, the matting of implementing the film behind the aforementioned stretching process is cleaned, with drying device 11 make this cleaning film drying drying process, on this dried film the stacked operation of stacked surface protective film.

The manufacture method of the polarizing film of present embodiment is undertaken by following process: a former winding up roller is arranged on aforementioned reel membrane supplying section 3, send continuously the reel film from this reel membrane supplying section 3, implement above-mentioned operation at its mobile route, finish at last stacked operation, resulting product (polarizing film) is implemented in polarizing film reeling end 10 batches coiling process into the roller shape.In addition, separately implement to connect operation as aforementioned the 2nd operation, in the described connection operation, prepare a plurality of former windings up roller in advance, before the first former winding up roller therein finishes, stretch out the reel film from the second new former winding up roller, the leading section 1b that makes this new reel film engages with the terminal part 1a of the first former winding up roller that gets ahead and is connected.

Thus, continue from this new former winding up roller with the reel membrane supplying to stretching device, implement aforementioned the 1st operation, make continuously polarizing film.In addition, by repeating to implement the 1st operation and the 2nd operation, can make continuously successively polarizing film.

Need to prove that the reel film (banded polyvinyl alcohol resin film) as supplying in such operation can adopt following film.

The reel film that uses in the manufacture method as the polarizing film of present embodiment, the film that can use the polyethenol series macromolecule resin material that used by the raw material as polarizing film to form.Particularly, such as processed film that can use polyvinyl alcohol film, partly-hydrolysed polyvinyl alcohol film or polyvinyl alcohol etc.

Usually, these reel films use with the state of the former winding up roller that is wound into as mentioned above the roller shape.

The degree of polymerization as the polymer of the formation material of aforementioned polyvinyl alcohol resin film is generally 500～10, and 000, preferably 1,000～6,000 scope, more preferably at Isosorbide-5-Nitrae 00～4,000 scope.

And then in the situation for partly-hydrolysed polyvinyl alcohol film, its saponification degree is for example considered aspect the dissolubility water, is preferably more than 75 % by mole, more preferably more than 98 % by mole, further preferably 98.3～99.8 % by mole scope.

As aforementioned polyvinyl alcohol resin film, the film that can suitably use any means film forming such as the tape casting by the stoste casting film-forming that will be dissolved in gained in water or the organic solvent, casting (cast method), extrusion molding to obtain.

The phase difference value of reel film is preferably 5nm～100nm.

In addition, in order to obtain the polarizing film of homogeneous in the face, the phase difference deviation in the preferably polyethylene alcohol based resin film face is as far as possible little.Be below the 10nm measuring wavelength 1000nm place preferably as phase difference deviation in the face of the polyvinyl alcohol resin film of reel film, more preferably below the 5nm.

Need to prove that the suction state when engaging by laser welding is preferably the water absorption rate of 2 quality %～15 quality %, more preferably the water absorption rate of 4 quality %～10 quality %.

When the reel film before being connected had above the water absorption rate of 15 quality %, existence heating and melting section when laser welding produced easily because of the foaming that the moisture evaporation causes, causes the worry that joint is bad.

On the contrary, during water absorption rate less than 2 quality %, the worry that exists the Resin Flow of the part that the reel film is heated with laser not enough, causes joint efficiency to reduce.

The water absorption rate of the reel film that therefore, uses during joint is preferably in above-mentioned scope.

Need to prove, about this water absorption rate, obtain by the quality before and after relatively drier, for example, can carry out heating in 83 ℃ * 1 hour to the polyvinyl alcohol resin film, with the quality of this weight loss on heating divided by the front polyvinyl alcohol resin film of heating, thereby obtain.

Below, describe being used for by aforementioned stretching device above-mentioned reel film being applied each operation that stretches and be processed into polarizing film.

(swelling operation)

In this operation, for example, utilize aforementioned roller 9 to guide to water-filled swelling from the reel film that reel membrane supplying section 3 sends with keeping constant translational speed and bathe the 4a, make aforementioned reel thin film dipped in water.

Can wash the reel film thus, clean dirt, the anticaking agent of reel film surface, and, make the reel films swell by utilizing water, the effect of the unequal inhomogeneity of can expecting to prevent to dye.

In the swelling solution in aforementioned swelling bath 4a, beyond dewatering, can also suitably add glycerine, KI etc.When adding them, if be glycerine, then its concentration is preferably below the 5 quality %, if be KI, then its concentration is preferably below the 10 quality %.

The temperature of swelling solution is preferably 20～45 ℃ scope, more preferably 25～40 ℃.

The dip time that aforementioned reel film floods in aforementioned swelling solution is preferably 2～180 seconds, more preferably 10～150 seconds, is particularly preferably 30～120 seconds.

In addition, can in this swelling is bathed, the polyvinyl alcohol resin film be stretched along its length, stretching ratio at this moment preferably include because of swelling cause extend in be about 1.1～3.5 times.

(dyeing process)

For the film that has passed through aforementioned swelling operation, with the swelling operation similarly, utilize roller 9 that it be impregnated in the dyeing liquor that is stored among the dye bath 4b, implement dyeing process.

For example, can adopt by dipping in the dyeing liquor that comprises the dichroic substance such as iodine and pass through the polyvinyl alcohol resin film of swelling operation, make the method for the above-mentioned dichroic substance of thin film adsorbs, implement aforementioned dyeing process.

As aforementioned dichroic substance, can use in the past known material, such as listing iodine, organic dyestuff etc.

As organic dyestuff, for example can use: red BR, red LR, red R, pink LB, ruby red BL, purplish red (Bordeaux) GS, skyblue LG, lemon yellow, blue BR, blue 2R, navy blue RY, green LG, purple LB, purple B, black H, black B, black GSP, yellow 3G, yellow R, orange LR, orange 3R, scarlet (Scarlet) GL, scarlet KGL, Congo red, brilliant violet BK, super indigo plant (Supra Blue) G, super indigo plant (Supra Blue) GL, super orange (Supra Orange) GL, direct sky blue, directly forever consolidate orange (Direct Fast Orange) S, forever admittedly black (Firstblack) etc.

These dichroic substance can only be used a kind of, also can be used in combination two or more.

When using aforementioned organic dyestuff, for example consider that from the neutralisation aspect of seeking the visible region preferred compositions is two or more.

As concrete example, can list: the combination of Congo red and super indigo plant (Supra Blue) G, super orange (Supra Orange) GL and direct sky blue or direct sky blue and forever solid black combination etc.

As the dyeing liquor of aforementioned dye bath, can use the solution that aforementioned dichroic substance is dissolved in gained in the solvent.

As aforementioned solvents, generally can make water, can also further add the organic solvent that compatibility is arranged with glassware for drinking water.

As the concentration of the dichroic substance in this dyeing liquor, preferably in the scope of 0.010～10 quality %, more preferably in the scope of 0.020～7 quality %, be particularly preferably 0.025～5 quality %.

In addition, when using iodine as aforementioned dichroic substance, can further improve dyeing efficient, therefore the preferred iodide that further add.

As these iodide, such as listing: KI, lithium iodide, sodium iodide, zinc iodide, silver iodide, lead iodide, cupric iodide, barium iodide, calcium iodide, stannic iodide, titanium iodide etc.

The interpolation ratio of these iodide is preferably 0.010～10 quality % in aforementioned dye bath, more preferably 0.10～5 quality %.

Wherein, particularly preferably add KI, the ratio of iodine and KI (mass ratio) is preferably in the scope of 1:5～1:100, more preferably in the scope of 1:6～1:80, particularly preferably in the scope of 1:7～1:70.

The dip time of film in aforementioned dye bath is not particularly limited, preferably 0.5～20 minute scope, more preferably 1～10 minute scope.In addition, the temperature of dye bath is preferably 5～42 ℃ scope, more preferably 10～35 ℃ scope.

In addition, also can in this dye bath film be stretched along its length, total stretching ratio of the accumulative total of this moment is preferably about 1.1～4.0 times.

Need to prove, as dyeing process, except the aforesaid method that is immersed in the dye bath, for example can adopt the aqueous solution coating that will comprise dichroic substance or be sprayed at method on the aforementioned polymer film.

In addition, among the present invention, as employed reel film, also can adopt and not carry out dyeing process and by mixing in advance the film that has the polymer raw material of dichroic substance film forming to obtain.

(crosslinked operation)

Then, film is imported among the crosslinked bath 4c that has crosslinking agent liquid, in aforementioned crosslinking agent liquid, implement crosslinked operation with thin film dipped.

As aforementioned crosslinking agent, can use in the past known material.

Such as using the boron compounds such as boric acid, borax, glyoxal, glutaraldehyde etc.

These can only use a kind of, also can be used in combination two or more.

Be used in combination when two or more, the combination of preference such as boric acid and borax, in addition, its adding proportion (mol ratio) preferably in the scope of 4:6～9:1, more preferably in the scope of 5.5:4.5～7:3, most preferably is 6:4.

Crosslinking agent liquid as aforementioned crosslinked bath can use the liquid that aforementioned crosslinking agent is dissolved in gained in the solvent.

As aforementioned solvents, for example can make water, also can further be used in combination the organic solvent that compatibility is arranged with glassware for drinking water.The concentration of the crosslinking agent in the aforementioned crosslinking agent liquid is not particularly limited, preferably in the scope of 1～10 quality %, and 2～6 quality % more preferably.

In the crosslinking agent liquid in the aforementioned crosslinked bath, can also add be used to the iodide of giving homogeneous characteristic in the polarizing film face.

As these iodide, such as listing KI, lithium iodide, sodium iodide, zinc iodide, silver iodide, lead iodide, cupric iodide, barium iodide, calcium iodide, stannic iodide, titanium iodide etc., when adding these iodide, the content of iodide is preferably 0.05～15 quality %, more preferably 0.5～8 quality %.

As the combination of crosslinking agent and iodide, the combination of preferred boric acid and KI, the ratio of boric acid and KI (mass ratio) is preferably in the scope of 1:0.1～1:3.5, more preferably in the scope of 1:0.5～1:2.5.

The temperature of the crosslinking agent liquid in the aforementioned crosslinked bath is usually preferably 20～70 ℃ scope, and the dip time of polyvinyl alcohol resin film is generally 1 second～arbitrary time in 15 minutes the scope, be preferably 5 seconds～10 minutes.

In this crosslinked operation, can in crosslinked bath film be stretched along its length, the total stretching ratio of accumulative total of this moment is preferably about 1.1～5.0 times.

Need to prove, as crosslinked operation, can be same with dyeing process, replace being immersed in the processing method in the crosslinking agent liquid, the method that contains cross-linking agent solution by coating or spraying is implemented.

(stretching process)

Aforementioned stretching process is to have carried out the operation that dyeing, crosslinked polyvinyl alcohol resin film stretch along its length direction take total stretching ratio of for example adding up as hereinafter described as about 5.25～8 times mode.In the wet type pulling method, under the state in the thin film dipped solution that is being stored in stretch bath, apply tension force along its length direction, implement to stretch.

Solution as being stored in the stretch bath is not particularly limited, and for example can use the solution of the compound that is added with various slaines, iodine, boron or zinc.

As the solvent of this solution, can suitably make water, ethanol or various organic solvent.

Wherein, particularly preferably use the boric acid be added with respectively about 2～18 quality % and/or the solution of KI.

When using simultaneously this boric acid and KI, it contains proportional (mass ratio) and is preferably about 1:0.1～1:4, more preferably about 1:0.5～1:3.

As the temperature of the solution in the aforementioned stretch bath, for example preferably 40～67 ℃ scope, more preferably 50～62 ℃.

(matting)

Thereby this matting is such as by making film by rinse out the operation of the unwanted residues such as boric acid that adhere in the cleaner bath that has the cleaning fluids such as water in the processing before this operation.

The preferred iodide that add for example preferably add sodium iodide or KI in the aforementioned water.

When adding KI in the water of cleaner bath, its concentration is generally 0.1～10 quality %, is preferably 3～8 quality %.

And then the temperature of cleaning fluid is preferably 10～60 ℃, more preferably 15～40 ℃.

In addition, returning of cleaning treatment counted, namely is immersed in the number of repetition of mentioning from cleaning fluid afterwards in the cleaning fluid and be not particularly limited, can be for repeatedly, thus also can be by kind, the concentration of in a plurality of cleaner bath, storing in advance additive different water and make film pass through their to implement matting.

Need to prove, when mentioning in the dipping bath of film from each operation, in order to prevent the generation of liquid sagging, can utilize and in the past knownly remove the liquid roller or ream the methods such as liquid by air knife to remove unnecessary moisture with pinch roll etc.

(drying process)

Film for having carried out cleaning in aforementioned matting can import it in aforementioned drying machine 11, suitably utilizes the method for the bests such as natural drying, air-dry, heat drying to make its drying, implements this drying process.

Wherein, if implement drying process by heat drying, then the condition of heat drying is preferably: heating-up temperature is about 20～80 ℃, be about 1～10 minute drying time.

And then irrelevant with preceding method, in order to prevent the deteriorated of film, preferred baking temperature is low temperature as far as possible.

More preferably below 60 ℃, be particularly preferably below 45 ℃.

(stacked operation) and (coiling process)

In the present embodiment, batch through the coiling process of film of above operation with takers-in by implementing, can obtain to be wound as the polarizing film of roller shape.

Need to prove, in the present embodiment, can after the suitable laminate surface protection in surperficial one or both sides of the polarizing film of having implemented to be undertaken by drying process dry stacked operation with film etc., implement coiling process.

Final total stretching ratio of the polarizing film of making like this is arbitrary stretching ratio in 5.25～8.0 times the scope with respect to the reel film preferably, more preferably the arbitrary stretching ratio in 5.5～7.0 times the scope.

Be preferably above-mentioned stretching ratio and be because, during 5.25 times of final total stretching ratio less thaies, have the worry that is difficult to obtain have the polarizing film of high polarized light property, when surpassing 8.0 times, have the worry of film fracture.

In addition, the final total stretching ratio of this polarizing film is the arbitrary stretching ratio in disengaged (being the reel film) is 5.25～8.0 times scope preferably, more preferably the interior arbitrary stretching ratio of 5.5～7.0 times scope.

(connection operation)

As previously described, in the present embodiment, the connection operation that is implemented as follows (aforementioned the 2nd operation): before a former winding up roller all is fed in the stretching device, stretch out polyvinyl alcohol resin film (reel film) from the former winding up roller of the next one, the leading section 1b of the reel film that this is new with the state that overlaps with the terminal part 1a of the former winding up roller of in stretching device, having implemented each operation with terminal part 1a joint and be connected.In addition, in connecting operation, take leading section 1b and terminal part 1a overlap, the initial elastic modulus at junction surface engages as the mode below 100% more than 65% with respect to the initial elastic modulus of disengaged section.

Engage by the as above terminal part of the operation first reel film that will get ahead and the leading section of next reel film, even giving the necessary high stretching ratio of high polarisation function, for example also not fracture ground connection under the stretching ratio more than 5.25 times.Thus, even in the situation that the junction surface is passed through, also can transfer in the operation (aforementioned the 1st operation) of the second reel film that stretches, can effectively make polarizing film with not changing stretching condition.

That is, can not change stretching condition ground the first reel film and the second reel film are passed through stretching device continuously, thereby can obtain the effect that operating efficiency improves, productivity ratio improves, yield rate improves and waste of material reduces.

Need to prove that this connection operation is not implemented after need to not finishing fully in the operation (aforementioned the 1st operation) of the first reel film that stretches, for example, can be at rear section side and the 1st operation parallel practice of aforementioned the 1st operation.

For example, can use at aforementioned jockey and aforementioned swelling and bathe the stretching device that possesses reservoir (accumulator) between the 4a, with the first former winding up roller by aforementioned reservoir and supply to swelling and bathe among the 4a, near the complete part of the fast volume of this first former winding up roller the time, it is halted state that the limit makes its terminal part, the reel membrane supplying that the limit will be stored in the aforementioned reservoir is bathed the 4a side to swelling, implement the stretching (aforementioned the 1st operation) of aforementioned the first reel film, and implement will new former winding up roller by laser welding leading section be connected the connection operation of terminal part connection.

In addition, after the connection operation that also can implement in advance 2 banded polyvinyl alcohol resin films are connected, begin a polyvinyl alcohol resin film in the banded polyvinyl alcohol resin film that connects stretch (aforementioned the 1st operation).

The terminal part that aforementioned connection operation can be by making aforementioned the first polyvinyl alcohol resin film and the leading section of the aforementioned second banded polyvinyl alcohol resin film overlaps and the interface portion of the aforementioned terminal part of such coincidence and aforementioned leading section is carried out laser welding implement.Particularly, either party that can be in the leading section 1b of the terminal part 1a of the film that gets ahead and new film or both sides' surface-coated light absorber, form new and old reel film and coincide with the upper and lower configuration on platform 40, the limit adds flanging to this coincidence part irradiation laser with 50 pairs of these coincidence parts of aforementioned pressure-producing part, so that both sides' resin is compatible in film interface, form weld portion 30, thereby implement.

At this moment, in order to engage as the mode below 100% more than 65% with respect to the initial elastic modulus of disengaged section take the initial elastic modulus at junction surface, suitably the conditions such as the power density of the above-mentioned laser of setting, cumulative exposure are shone laser to coincidence part under the condition of setting.

Thus in the present embodiment by utilizing laser to carry out welding, optionally (partly) thus interface and near heating thereof in the coincidence part of new and old reel film are heated, therefore, the junction surface is softening easily.Thus, the initial elastic modulus that carries out easily the junction surface is the joint below 100% more than 65% with respect to the initial elastic modulus of disengaged section.

When engaging with respect to the mode of the initial elastic modulus less than 65% of disengaged section with the initial elastic modulus at junction surface, with respect to disengaged section, the junction surface is too soft, therefore, on the stretching process limit stretching ratio is set as 5.25 times with the top continuously during stretching polyethylene alcohol based resin film, the easy fracture of the boundary member of junction surface and disengaged section.When particularly the junction surface is too soft, the easy fracture in junction surface.

With respect to this, engage by the mode more than 65% take the initial elastic modulus at junction surface as the initial elastic modulus of disengaged section, the junction surface can be too not soft, the hardness at junction surface and the hardness of disengaged section are very approaching, the stress that therefore, can fully relax above-mentioned boundary member is concentrated.Therefore, can the limit stretching ratio be set as 5.25 times with top stretching polyethylene alcohol based resin film continuously.

In addition, consider from relaxing more fully the viewpoint that above-mentioned stress concentrates, preferably engage as the mode more than 70% with respect to the initial elastic modulus of above-mentioned disengaged section take the initial elastic modulus at above-mentioned junction surface.

On the other hand, when surpassing 100% mode and engage with respect to the initial elastic modulus of above-mentioned disengaged section with the initial elastic modulus at above-mentioned junction surface, with respect to disengaged section, the junction surface is really up to the mark, stress concentrates on above-mentioned boundary member easily in stretching process, therefore easy fracture.

With respect to this, by engaging as the mode below 100% with respect to the initial elastic modulus of above-mentioned disengaged section take the initial elastic modulus at above-mentioned junction surface, with respect to disengaged section, the junction surface can be not really up to the mark, the hardness at junction surface and the hardness of disengaged section are very approaching, the stress that therefore, can relax above-mentioned boundary member is concentrated.Therefore, can the limit stretching ratio be set as 5.25 times with top stretching polyethylene alcohol based resin film continuously.

In addition, consider from relaxing more fully the viewpoint that above-mentioned stress concentrates, preferably engage as the mode below 90% with respect to the initial elastic modulus of above-mentioned disengaged section take the initial elastic modulus at above-mentioned junction surface.

Here, the initial elastic modulus at above-mentioned junction surface can be such as the mensuration of getting off (with reference to Fig. 4～Fig. 6).

That is, cut (the length direction length 1.5mm of polyvinyl alcohol resin film) * (the width length 20mm of polyvinyl alcohol resin film) zone 33 in the junction surface 31.Then, use has the tensile test apparatus (not shown) of fixed part chuck 37 and movable chuck 38, the junction surface as the junction surface that cuts is cut into slices 35 in along its length (being the TD direction of above-mentioned width, Fig. 6) stretching under initial chuck spacing 10mm, draw speed 0.1mm/min under 20 ℃ of environment of room temperature, carry out thus tension test, stress and strain is measured in junction surface section 35, obtained load-deformation curve.Then, the stress 1N/mm in the calculating gained load-deformation curve ²Under tangent slope (with reference to Fig. 7).The tangent slope of calculating thus is the initial elastic modulus at junction surface.

In addition, cut (above-mentioned length direction length 3.0mm) * (above-mentioned width length 20mm) zone 34 in disengaged 32.Then, with above-mentioned same, use has the tensile test apparatus (not shown) of fixed part chuck 37 and movable chuck 38, with cut as disengaged of disengaged section section 36 under 20 ℃ of environment of room temperature under initial chuck spacing 10mm, draw speed 0.1mm/min along its length (being the TD direction of above-mentioned width, Fig. 6) stretch, carry out thus tension test, stress and strain is measured in disengaged section 36, obtained load-deformation curve.Then, the stress 1N/mm in the calculating gained load-deformation curve ²Under tangent slope.The tangent slope of calculating thus is the initial elastic modulus of disengaged section.

Need to prove, as tensile test apparatus, can use heat to analyze determinator (TMA, SII NanoTechnology Inc. manufacturing, EXSTAR TMA/SS6200).

In addition, the length direction length 3.0mm that makes disengaged section be 2 times of length direction length 1.5mm of junction surface section be for: by 2 polyvinyl alcohol resin films being overlapped and engaging, when the thickness at junction surface is 2 times with respect to the thickness of disengaged section, make the sectional area of junction surface section and disengaged section equal.

By as mentioned above take the initial elastic modulus at junction surface with respect to the initial elastic modulus of disengaged section as the mode below 100% more than 65% engages, can relax the boundary member that the stress that is caused by stretching concentrates on junction surface and disengaged section.Thus, for example, also can avoid above-mentioned border fracture even stretch with the stretching ratio more than 5.25 times, to apply continuously stretching even also can not change stretching condition ground in the situation about passing through at the junction surface.Therefore, can obtain the effect that operating efficiency improves, productivity ratio improves, yield rate improves and waste of material reduces.

In addition, by utilizing laser welding to engage, can be only locally to the interface of terminal part and leading section and near heat, the zone that can reduce to solidify in the junction surface, therefore, engage as the mode below 100% more than 65% with respect to the initial elastic modulus of disengaged section take the initial elastic modulus at junction surface easily.

With respect to this, when for example utilizing heat sealing machine to engage, terminal part and junction surface are heated by globality ground at thickness direction, therefore, it is large that the zone of the curing at junction surface becomes, and is difficult to the tendency that engages as the mode below 100% more than 65% with respect to the initial elastic modulus of disengaged section take the initial elastic modulus at junction surface thereby exist.

Therefore, and utilize heat sealing machine to engage to compare, it is preferred utilizing laser welding to engage as present embodiment.But, if can be take the initial elastic modulus at junction surface with respect to the initial elastic modulus of disengaged section as the mode below 100% more than 65% engages, then also can utilize heat sealing machine to engage, in addition, can also use other joint method to engage.

Need to prove that utilize the thickness of polarizing film of the manufacture method manufacturing of present embodiment to be not particularly limited, the thickness of preferred disengaged section is 5 μ m～40 μ m.

If the thickness of disengaged section is that then mechanical strength can not reduce more than the 5 μ m, in addition, if be that then optical characteristics can not reduce below the 40 μ m, be applied to image display device and also can realize slimming.

The polarizing film that utilizes the polarizing film of present embodiment manufacturing can be used as to be laminated in liquid crystal cell substrate etc. is used for liquid crystal indicator etc.In addition, except liquid crystal indicator, can also use as the polarizing film in the various image display devices such as el display device, plasma display and Field Emission Display.

Need to prove, during actual the use, can also be on the two sides or the stacked various optical layers of one side form optical thin films or implement various surface treatments and be used for the image display device such as liquid crystal indicator.

As aforementioned optical layers; as long as satisfying desired optical characteristics just is not particularly limited; for example; be the protective clear layer of purpose, aligned liquid-crystal layer take vision compensation etc. as purpose, be used for beyond the adhesive layer of stacked other film divided by the protection polarizing film, can also use the film that in the formation of image display devices such as polarization conversion element, reflecting plate, half transmitting plate, polarizer (comprising 1/2,1/4 equiwavelength's plate (λ plate)), vision compensation film, bright enhancement film etc., uses.

In addition, as surface treatment, can list firmly be coated with processing, antireflection process, take antiseized, non-proliferation or anti-dazzle surface treatment as purpose.

The manufacture method of the polarizing film of present embodiment as previously discussed, but the present invention is not limited to present embodiment, it can suitably design alteration in purport scope of the present invention.In addition, the action effect of the manufacture method of polarizing film of the present invention also is not limited to above-mentioned action effect.

Embodiment

Below, enumerate embodiment and illustrate in greater detail the present invention, but the present invention is not limited thereto.

(evaluation Example)

(primary condition)

Reel film: polyvinyl alcohol resin (PVA) film (manufacturing of (strain) Kuraray company, thickness 75 μ m, width 50mm, water absorption rate 6%)

Overlap width: 1.5mm width

Heating and melting junction surface: laser

Laser: semiconductor laser (wavelength 940nm, power 95W, spot diameter

Power density 3024W/cm ², sweep speed 55mm/sec, cumulative exposure 110J/cm ², flat top beam)

Light absorber: trade name " Clearweld(registration mark) LD120C " (Gentex Corporation system, solvent acetone), with the 2.0mm width, with 10nL/mm ²Be coated on the upper surface of the reel film that is disposed at downside

Pressure-producing part: quartz glass plate (10mm is thick)

Pressurized conditions: with pressure 50kgf/cm ²By being pressed on the reel film coincidence part

(appreciation condition)

Tension test: thermo-mechanical analysis device (TMA, SII NanoTechnology Inc. manufacturing, EXSTAR TMA/SS6200), initial chuck spacing 10mm, draw speed 0.1mm/min

(embodiment 1)

Under above-mentioned primary condition, 2 reel films are connected, cut the zone of (the length direction length 1.5mm of reel film) in the junction surface * (the width length 20mm of reel film), take rectangular-shaped junction surface section.In addition, cut the zone of (above-mentioned length direction length 3.0mm) in disengaged * (above-mentioned width length 20mm), take disengaged rectangular-shaped section.To these junction surface section and disengaged section, under above-mentioned appreciation condition, carry out respectively tension test, obtain load-deformation curve, calculate the stress 1N/mm in the curve obtained ²Under tangent slope, calculate initial elastic modulus.Its result, the initial elastic modulus at junction surface is that the initial elastic modulus of 0.21GPa, disengaged section is 0.30GPa, is 70.0% with respect to the initial elastic modulus at the junction surface of the initial elastic modulus of disengaged section.Show the result in table 1 and Fig. 8.

In addition, under the condition identical with this condition, 2 reel films are connected, about 50mm is long before and after cutting the junction surface, use stretching device shown in Figure 1, take total stretching ratio in swelling is bathed as 2.6 times, in dye bath as 3.4 times, in crosslinked bath as 3.6 times, in stretch bath after 6.0 times mode stretches, by cleaner bath, be produced in batches thus polarizing film.Its result, being stretched to 6.0 times of total stretching ratios does not have fracture yet.

(embodiment 2)

Laser power is changed to 100W, in addition, under above-mentioned primary condition, 2 reel films are engaged, take similarly to Example 1 the junction surface section, measure the initial elastic modulus of the junction surface section of taking.Its result, the initial elastic modulus at junction surface is 0.22GPa.In addition, as the initial elastic modulus of disengaged section, use the 0.30GPa of embodiment 1, calculate the initial elastic modulus with respect to the junction surface of the initial elastic modulus of disengaged section.Its result is 73.3% with respect to the initial elastic modulus at the junction surface of the initial elastic modulus of disengaged section.Show the result in table 1 and Fig. 8.

In addition, under the condition identical with this condition 2 reel films are connected, operation is produced in batches polarizing film similarly to Example 1.Its result is not even have fracture total be stretched to 6.0 times of stretching ratios yet.

(embodiment 3)

Sweep speed is changed to 30mm/sec, in addition, under above-mentioned primary condition, 2 reel films are engaged, take similarly to Example 1 the junction surface section, measure the initial elastic modulus of the junction surface section of taking.Its result, the initial elastic modulus at junction surface is 0.28GPa.In addition, as the initial elastic modulus of disengaged section, use the 0.30GPa of embodiment 1, calculate the initial elastic modulus with respect to the junction surface of the initial elastic modulus of disengaged section.Its result is 93.3% with respect to the initial elastic modulus at the junction surface of the initial elastic modulus of disengaged section.Show the result in table 1 and Fig. 8.

In addition, under the condition identical with this condition 2 reel films are connected, making the total stretching ratio in the stretch bath is 5.5, and in addition, operation is produced in batches polarizing film similarly to Example 1.Its result is not even have fracture total be stretched to 5.5 times of stretching ratios yet.

(embodiment 4)

The width of reel film is changed to 2600mm, in addition, under above-mentioned primary condition, new and old reel film is engaged, use stretching device shown in Figure 1, take total stretching ratio in swelling is bathed as 2.6 times, in dye bath as 3.4 times, in crosslinked bath as 3.6 times, in stretch bath as 6.0 times mode by roll-to-roll manufacturing polarizing film.Its result similarly to Example 1, even also do not have fracture total be stretched to 6.0 times of stretching ratios, can pass through continuously.Need to prove that the difference of the width of reel film does not exert an influence to the initial elastic modulus of junction surface and disengaged section, therefore, the initial elastic modulus at the above-mentioned junction surface with respect to disengaged section among this embodiment 4 is 70.0% similarly to Example 1.

(comparative example 1)

The overlap width that makes new and old reel film is 3mm,, uses the nichrome wire of width 3mm to implement heat-sealing under 250 ℃, 10 seconds heating condition here, forms the weld portion of wire.Except above-mentioned situation, similarly to Example 12 reel films are engaged.In addition, take similarly to Example 1 the junction surface section, measure similarly to Example 1 the initial elastic modulus of the junction surface section of taking.Its result, the initial elastic modulus at junction surface is 0.33GPa.In addition, as the initial elastic modulus of disengaged section, use the 0.30GPa of embodiment 1, calculate the initial elastic modulus with respect to the junction surface of the initial elastic modulus of disengaged section.Its result is 110.0% with respect to the initial elastic modulus at the junction surface of the initial elastic modulus of disengaged section.Show the result in table 1 and Fig. 8.

In addition, under the condition identical with this condition 2 reel films are connected, similarly to Example 1, making the total stretching ratio in the stretch bath is 6.0, is produced in batches polarizing film.Its result, fracture when being stretched to 4.3 times of total stretching ratios.

(comparative example 2)

With laser power change to 50W, power density changes to 1592W/cm ², sweep speed changes to 5mm/sec, cumulative exposure changes to 637J/cm ², in addition, under above-mentioned primary condition, 2 reel films are engaged.Take similarly to Example 1 the junction surface section, measure the initial elastic modulus of the junction surface section of taking.Its result, the initial elastic modulus at junction surface is 0.31GPa.In addition, as the initial elastic modulus of disengaged section, use the 0.30GPa of embodiment 1, calculate the initial elastic modulus with respect to the junction surface of the initial elastic modulus of disengaged section.Its result is 103.3% with respect to the initial elastic modulus at the junction surface of the initial elastic modulus of disengaged section.Show the result in table 1 and Fig. 8.

In addition, under the condition identical with this condition 2 reel films are connected, operation is produced in batches polarizing film similarly to Example 1.Its result, fracture when being stretched to 5.25 times of total stretching ratios.

(comparative example 3)

Between the coincidence part of pressure-producing part and reel film, and this coincidence part and platform between polyimides (PI) film of inserting thickness 125 μ m respectively, in addition, under above-mentioned primary condition, 2 reel films are engaged.Take similarly to Example 1 the junction surface section, measure the initial elastic modulus of the junction surface section of taking.Its result, the initial elastic modulus at junction surface is 0.19GPa.In addition, as the initial elastic modulus of disengaged section, use the 0.30GPa of embodiment 1, calculate the initial elastic modulus with respect to the junction surface of the initial elastic modulus of disengaged section.Its result is 63.3% with respect to the initial elastic modulus at the junction surface of the initial elastic modulus of disengaged section.Show the result in table 1 and Fig. 8.

In addition, under the condition identical with this condition 2 reel films are connected, operation is produced in batches polarizing film similarly to Example 1.Its result, fracture when being stretched to 5.8 times of total stretching ratios.

[table 1]

Claims

1. the manufacture method of a polarizing film is characterized in that, it is to use a plurality of banded polyvinyl alcohol resin films to make continuously the method for polarizing film,

The manufacture method of this polarizing film has following operation:

In described the 2nd operation, engage, so that the initial elastic modulus at junction surface is more than 65% below 100% with respect to the initial elastic modulus of disengaged section.

2. the manufacture method of polarizing film according to claim 1 is characterized in that, by utilize laser welding with described terminal part be connected leading section and engage and to connect, thereby implement described the 2nd operation.

3. the manufacture method of polarizing film according to claim 2 is characterized in that, implements described laser welding at the interface portion configuration light absorber of described terminal part and described leading section.

4. according to claim 2 or the manufacture method of 3 described polarizing films, it is characterized in that, utilize the following infrared laser of the above 11000nm of wavelength 800nm to implement described laser welding.

5. the manufacture method of polarizing film according to claim 1 and 2 is characterized in that, described the first polyvinyl alcohol resin film and described the second polyvinyl alcohol resin film separately disengaged and the stretching ratio at junction surface are more than 5.25 times.