CN107530892A

CN107530892A - Polyvinyl alcohol film

Info

Publication number: CN107530892A
Application number: CN201680027622.0A
Authority: CN
Inventors: 森保二郎; 佐藤直人; 村上晃
Original assignee: Kuraray Co Ltd
Current assignee: Kuraray Co Ltd
Priority date: 2015-05-13
Filing date: 2016-05-12
Publication date: 2018-01-02
Anticipated expiration: 2036-05-12
Also published as: TWI714581B; JPWO2016182010A1; WO2016182010A1; KR20180006899A; TW201708267A; JP6668338B2; CN107530892B; KR20200090959A; KR102330883B1

Abstract

The present invention relates to polyvinyl alcohol film 1, it is the polyvinyl alcohol film 1 for the strip that thickness is less than 55 μm, length is more than 500m, along at least one cut-out end A, A' to be formed by cutting edge of two ends of the length direction of film, cut-out end face B, B' of cut-out end maximum height roughness (Rz) is less than 2.5 μm in more than the length 500m of film section；And the polyvinyl alcohol film coils into the roller that web-like forms.

Description

Polyvinyl alcohol film

Technical field

The present invention relates to the slim polyvinyl alcohol film with specific cut-out end face (below, sometimes by " polyvinyl alcohol " Referred to as " PVA "), coiled into the manufacture method of roller that web-like forms and the PVA film for obtaining this PVA film.

Background technology

Polarizer with light transmission and shielding function is liquid crystal display together with the liquid crystal with light switch function (LCD) basic composed component.In recent years, this LCD suitable application area is also from the desktop computer and wrist in initial stage of development stage The miniature instrument of table etc. is expanded to notebook computer, word processor, color liquid crystal projecting apparatus, vehicle-mounted navigation system, liquid crystal The extensive field of the measuring instrument of TV, mobile phone and indoor and outdoor etc., consider from the side, it is necessary to higher quality and cheap Polarizer.

For polarizer, typically by following methods：Uniaxial tension is carried out after PVA film is dyed, or while is carried out Dyed again after dyeing while carrying out uniaxial tension or progress uniaxial tension, make the monadic stretching membrane after dyeing, used boron The method that processing is fixed in compound；When above-mentioned uniaxial tension is dyed and handled, consolidated simultaneously with boron compound with dyeing Surely method handled etc., after manufacturing polarizing coating, in the surface of polarizing coating fitting cellulose triacetate (TAC) film, acetate butyrate The diaphragm of cellulose (CAB) film etc., is manufactured therefrom.

When manufacturing polarizer, in order to reduce production cost etc., widely using following methods：Using by strip The embryophoric membrane volume (former anti-Off ィ Le system) that PVA film is rolled into a roll, continuously carries out uniaxial tension, dyeing, fixation, diaphragm fitting etc. Process.

It is easy relative to central portion, thickness, degree of drying at the both ends of the width of film caudacoria for PVA film Difference is produced, if carrying out uniaxial tension in the case where retaining the both ends of width, is difficult to stable stretching, because This is typically to coil into web-like after the both ends cut-out of the width of film is removed, and is supplied to the demand of polarizer manufacturer etc. Side.

In addition, as needed, in order to provide the film width for the requirement for meeting the party in request of polarizer manufacturer etc., it is also necessary to Obtained PVA film will be film-made while cut-out removes ear, or do not cut off and remove ear, in the center of the width of film Portion or other positions are cut off along its length, and film is made to required predetermined width, is coiled into web-like, there is provided to need The side of asking.

When manufacturing polarizing coating from PVA film, in order to obtain high polarization property, generally by PVA film with high stretching ratio in length Direction carries out uniaxial tension, if but the cut-out end face generating surface of film roughening, in uniaxial tension, mat surface part turns into The starting point being cracked, cracking is produced in end, or even in other instances, occurred as film from the cracking portion fractures not Good situation.When the situation of film fracture occurs, it is necessary to temporarily cease uniaxial tension processing, remove breaking portion, then carry out again Stretch processing, thus cause productivity to be greatly reduced, the productivity ratio of polarizing coating it is low.Consider from the side, it is desirable to when stretching It is not cracked, is broken, there is the smooth PVA film for cutting off end face along the length direction of film.

So far, it is known to the cutting-off method of several PVA films (with reference to patent document 1~3 etc.).In patent document 1 Method in particular range will be controlled respectively for the temperature of the PVA film of cut-out and volatile ingredient by disclosing, as cutting-off method, Disclose the method for film being cut off between 2 rollers, the method cut off on fluted roller.It is public in patent document 2 The optics PVA film with specific surface average roughness (Ra) is opened, as cutting-off method, disclosing to use includes upper slitter With the method for the distribution knife (シェア swords) of lower knife, the method for laser knife is used.Patent Document 3 discloses in the overall length of film The maximum height (Ry) for making cut-out end face is the PVA film of the strip of particular range, as cutting-off method, discloses use and is used for The method for forming the circular knife of each 1 rotation of 1 cut-out end, discloses the point of a knife angle using fluted roller and circular knife Preferably 3~20 °.

Prior art literature

Patent document

Patent document 1：JP 2002-144418 publications

Patent document 2:JP 2003-12827 publications

Patent document 3:JP 2005-306981 publications.

The content of the invention

Invent problem to be solved

In recent years, the thinner polarizing coating of demand, considers from the side, and the embryophoric membrane as polarizing coating manufacture is rolled up, generally in the past Using 75 μm or so of PVA film of thickness, but in recent years, it is desirable to 70 μm of thinner PVA films of thickness ratio.But for thin PVA Film, the problem of being easily broken compared with the film of conventional thickness in the processing of uniaxial tension etc. be present.

It is an object of the invention to provide a kind of slim PVA for being difficult to be broken in the processing of uniaxial tension etc. Film and coiled into the roller that web-like forms.It is in addition, this for successfully manufacturing the present invention also aims to provide The PVA film manufacture method of PVA film.

Solves the technological means of problem

The present inventor etc. to achieve the above object, by depth studying, as a result have found, for the strip below 55 μm of thickness PVA film, make in the specific section of the length direction of film, make its cut off end cut-out end face in maximum height roughness (Rz) it is specific scope, even thus slim PVA film, in the processing of uniaxial tension etc., it is also difficult to be broken.Separately Outside, the present inventor etc. has found, the PVA film before cut-out is contacted with fluted roller and is conveyed, while will using the circular knife of rotation When the PVA film is alongst cut off, as the circular knife, if using has specific point of a knife angle while point of a knife Partial hardness then can successfully manufacture the above-mentioned slim PVA film for being difficult to be broken in the circular knife of particular range.The present invention People etc. are had found based on these, are further studied repeatedly, so as to complete the present invention.

That is, the present invention relates to

[1] PVA film, it is the PVA film for the strip that thickness is less than 55 μm, length is more than 500m, along the length side of film To at least one of two ends be the cut-out end that is formed by cutting edge, the maximum height of the cut-out end face of the cut-out end Roughness (Rz) is less than 2.5 μm in more than the length 500m of film section；

The PVA film of [2] above-mentioned [1], wherein, cut off the arithmetic average roughness (Ra) of end face in above-mentioned section be 0.4 μm with Under；

[3] PVA film of above-mentioned [1] or [2], wherein, the length of film is more than 1000m；

[4] PVA film of any one of above-mentioned [1]~[3], it is the embryophoric membrane volume of optical film manufacture；

[5] PVA film of any one of above-mentioned [1]~[4], wherein, optical film is polarizing coating；

[6] roller, it is that the PVA film of any one of above-mentioned [1]~[5] is coiled into what web-like formed；

[7] manufacture method, it along at least one of two ends of the length direction of film is the cut-out that is formed by cutting edge that it, which is, The manufacture method of end, thickness is less than 55 μm, length is more than 500m strip PVA film, wherein, there is following step Suddenly：The large-diameter portion contacted using having on roll axial direction with film and the fluted roller with the discontiguous minor diameter part of film, make the trough of belt The surface of the large-diameter portion of roller contacts with the PVA film of strip and conveyed, while the position of the minor diameter part in the fluted roller passes through The circular knife of rotation is alongst cut off PVA film, and the point of a knife angle of the circular knife is 25~50 °, point of a knife part Vickers hardness be more than 1500HV；

The manufacture method of [8] above-mentioned [7], wherein, circumference of the PVA film along fluted roller is contacted with 10~100 ° of angle；

[9] manufacture method of above-mentioned [7] or [8], it is the system for being used to manufacture the PVA film of any one of above-mentioned [1]~[5] Make method.

Invention effect

According to the present invention, there is provided be difficult to the slim PVA film that is broken in the processing of uniaxial tension etc. and batched coiled The roller that shape forms.In addition, according to the present invention, there is provided can successfully manufacture the manufacture method of the PVA film of this PVA film.

Brief description of the drawings

[Fig. 1] schematically shows the figure of a part for the PVA film of the present invention.

[Fig. 2] schematically shows figure of the circular knife in an example in the section of thickness direction.

[Fig. 3] schematically shows the one of the cutting-off method of an example of fluted roller and the PVA film of use fluted roller The figure of individual example.

Embodiment

Hereinafter, for the present invention, it is described in detail.

The PVA film of the present invention is the film of strip, at least one in two ends of the film alongst be by The cut-out end that cutting edge is formed.The PVA film can be turned off end, also may be used along the only one end of the length direction of film To be to be turned off end along two ends of the length direction of film, it is turned off preferably along two ends of the length direction of film End.The cutting edge for forming cut-out end is not particularly limited, such as can enumerate distribution knife, laser knife, circular knife etc., preferably For circular knife described later.

The present invention PVA film in, above-mentioned cut-out end cut-out end face maximum height roughness (Rz) film length More than 500m section is less than 2.5 μm.That is, in the case that the length of PVA film of the invention is 3000m, at least cutting In the continuum of any one 500m in the length in broken ends of fractured bone face, its maximum height roughness (Rz) is in above range.

Here, cut-out end face refers to cut-out end A, A ' (Fig. 1 expressions alongst as shown in figure 1, PVA film 1 Alongst two ends of PVA film 1 are the situation of cut-out end) in, equivalent to the face of the caliper portion of PVA film 1 (section) B, B '.

For above-mentioned maximum height roughness (Rz), using such as laser shape measuring microscope, (ultra-deep shape shape Measuring determines Microscopy Wei Mirror) etc., the surface roughness for cutting off end face is determined in the scope of specific length (L) along the length direction of cut-out end face, Obtain roughness curve, as the roughness curve average line (average line on the length direction of film) upper section most Value obtained from total (Rz=Rp+Rv) of big peak height (Rp) and the maximum valley depth (Rv) of section below, on its detailed feelings Condition, in JIS B 0601：Described in 2001.Above-mentioned roughness curve can be by the thickness on the cut-out end face as measure object Surface state of the direction central portion on the line of the length direction of film is obtained.Generally, when PVA film is cut off, since cut-out when, Process over time, section become coarse gradually, therefore cut off the above-mentioned maximum height roughness (Rz) of end face and aftermentioned Arithmetic average roughness (Ra) value since cut-out when, pass through over time and become big.Therefore, the place since cut-out Rise, cut off on the length direction of film in the part (measure place) after length-specific (such as 500m), determine it and cut off end face In maximum height roughness (Rz) and arithmetic average roughness (Ra), if these measured values below special value, can With say at least since cut-out start place to measure place whole region, its cut-out end face in maximum height roughness (Rz) with And arithmetic average roughness (Ra) is below these measured values.

For the PVA film of the present invention, from the viewpoint of fracture is prevented in the processing of uniaxial tension etc., above-mentioned cut-out end The maximum height roughness (Rz) in face is necessary for less than 2.5 μm, preferably less than 2 μm in more than the length 500m of film section, More preferably less than 1.5 μm, more preferably less than 1 μm, particularly preferably less than 0.9 μm.The maximum height roughness (Rz) lower limit is not particularly limited, preferably not following from the viewpoint of ease of manufacturing of PVA film of the present invention etc. The PVA film in section：The maximum height roughness (Rz) of cut-out end face is less than 0.01 μm in the length 500m of film section, more excellent Elect the PVA film in no following section as：The maximum height roughness (Rz) of cut-out end face is 0.1 in the length 500m of film section Below μm, the PVA film in more preferably no following section：Cut off length of the maximum height roughness (Rz) in film of end face 500m section is less than 0.3 μm.

For the PVA film of the present invention, if the arithmetic average roughness (Ra) of cut-out end face is being related to maximum height roughness (Rz) above-mentioned section is less than 0.4 μm, then in the processing of uniaxial tension etc., can effectively further prevent from being broken, be Preferably.Consider from this viewpoint, for the PVA film of the present invention, the arithmetic average roughness of more preferably above-mentioned cut-out end face (Ra) it is less than 0.3 μm in above-mentioned section, more preferably less than 0.2 μm, particularly preferably less than 0.14 μm.The arithmetic is put down The lower limit of equal roughness (Ra) is not particularly limited, and from the viewpoint of ease of manufacturing of PVA film of the present invention etc., is preferably PVA film without following section：The arithmetic average roughness (Ra) of cut-out end face is less than 0.001 μm in above-mentioned section, more Do not have the PVA film in following section preferably：Cut off end face arithmetic average roughness (Ra) above-mentioned section be 0.01 μm with Under, the further preferred PVA film without following section：Cut-out end face arithmetic average roughness (Ra) be in above-mentioned section Less than 0.03 μm.

Here, above-mentioned arithmetic average roughness (Ra) is, for what is obtained in maximum height roughness (Rz) measure Roughness curve (datum length：L), according to JIS B 0601：2001 record can be obtained.

For the PVA film of the present invention, from the viewpoint of the fracture during processing for effectively further preventing uniaxial tension etc. etc. Consider, be related to the above-mentioned section of maximum height roughness (Rz), preferably at most height roughness (Rz) and arithmetic mean roughness It is more than 5, more preferably more than 6 to spend the ratio between (Ra) (Rz/Ra), it is additionally preferred to is less than 25, more preferably less than 11.Than (Rz/ Ra) can be as the index of the wear intensity of the blade of the cut-out for PVA film, when the abrasion of blade are violent, most cases It is lower to diminish than (Rz/Ra), accompany with this, the degree for cutting off the face roughening of end face easily increases.

For the thickness of the PVA film of the present invention, the reasons why requiring thinner PVA film etc. from reply, considers, is less than 55 μm, Preferably less than 50 μm, more preferably less than 45 μm, more preferably less than 40 μm, particularly preferably less than 30 μm.The PVA The lower thickness limit of film is not particularly limited, and is examined from the viewpoint of practicality, the easiness of film manufacture, the easiness of stretch processing etc. Consider, the thickness is preferably more than 3 μm, more preferably more than 5 μm, more preferably more than 15 μm.

The width of the PVA film of the present invention can select according to the requirement of party in request etc. of the purposes of PVA film, PVA film, but Preferably generally more than 2m, more preferably more than 2.5m, more preferably more than 3m, additionally, it is preferred that being below 8m.

The length of the PVA film of the present invention is more than 500m., can be for a long time when being used from it for the length of the PVA film From the aspect of continuous use etc., preferably more than 1000m, more preferably more than 5000m, more preferably more than 8000m. The upper limit of the length is not particularly limited, and the length for example can be below 30000m.For the present invention PVA film, from carry, From the viewpoint of easiness taken care of and used etc., the form for the roller that web-like forms preferably is coiled into.

As form the present invention PVA film PVA, such as can enumerate by vinyl esters polymerize obtained by polyvinyl ester enter Modified PVA obtained by graft copolymerization comonomer on unmodified PVA, PVA main chain obtained by row saponification, by vinyl esters and altogether Modified PVA that modified poly ethylene base ester obtained by polycondensation monomer copolymerization carries out saponification and manufactured, by unmodified PVA or modified PVA The part formalin of hydroxyl, butyraldehyde, benzaldehyde etc. aldehydes crosslinking obtained by so-called Pioloform, polyvinyl acetal tree Fat etc..

Formed the PVA film of the present invention PVA be modified PVA in the case of, the modified amount in PVA be preferably 15 moles of % with Under, more preferably 5 moles of below %.

Above-mentioned vinyl esters used in manufacture as PVA, such as vinyl formate, vinyl acetate can be enumerated Ester, propionate, vinyl butyrate, vinyl valerate, new vinyl acetate acid, vinyl laurate, stearic acid vinyl ester, benzene Sour (versatic acid) vinyl acetate of vinyl formate, branched paraffin etc..These vinyl esters can individually or combination makes With.In these vinyl esters, vinyl acetate is preferable from the viewpoint of productivity.

In addition, as above-mentioned comonomer, such as the carbon number of ethene, propylene, 1- butylene, isobutene etc. can be enumerated 2~30 olefines (alpha-olefin etc.)；Acrylic acid or its salt；Methyl acrylate, ethyl acrylate, n-propyl, propylene Isopropyl propionate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, 2-EHA, acrylic acid 12 The esters of acrylic acid (such as, the Arrcostab of carbon number 1~18 of acrylic acid) of Arrcostab, octadecyl acrylate etc.；Methyl Acrylic acid or its salt；Methyl methacrylate, EMA, n propyl methacrylate, isopropyl methacrylate, N-BMA, Isobutyl methacrylate, Tert-butyl Methacrylate, 2-Ethylhexyl Methacrylate, methyl Dodecylacrylate, octadecyl methacrylate etc. methyl acrylic ester (such as, the carbon of methacrylic acid it is former The Arrcostab of subnumber 1~18)；Acrylamide；N methacrylamide, N- ethyl acrylamides, N, it is N- DMAAs, double Acetone acrylamide, acrylamide propane sulfonic or its salt, acrylamide propyl-dimethyl amine or its salt, N- methylol acryloyls The acrylamide derivative of amine or derivatives thereof etc.；Methacrylamide, N- methyl methacrylamides, N- ethyl-methyl propylene Acid amides, Methacrylamide propane sulfonic acid or its salt, dimethylaminopropyl methacrylamide or its salt, N- hydroxymethyl, methyls third The methacrylamide derivatives of acrylamide or derivatives thereof etc.；N- vinyl formamides, N- vinyl acetamides, N- vinyl The N- vinylamide classes of pyrrolidones etc.；Methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl second Alkene ether, n-butyl vinyl ether, IVE, tert-Butyl vinyl ether, dodecyl vinyl, stearyl second The vinyl ethers of alkene ether etc.；The nitrile of acrylonitrile, methacrylonitrile etc.；Vinyl chloride, vinylidene chloride, PVF, inclined fluorine second The vinyl halides class of alkene etc.；The allyl compound of allyl acetate, allyl chloride etc.；The insatiable hunger of maleic acid, itaconic acid etc. With the derivative of dicarboxylic acids, its salt or its ester etc.；The vinyl silyl groups compound of vinyltrimethoxy silane etc.；Second The different propylene of acid；Unsaturated sulfonic acid or derivatives thereof etc..These comonomers can be used alone, or can by 2 kinds with On be used in combination.In these comonomers, preferred alpha-olefin, particularly preferred ethene.

It is inclined from that can obtain when by the PVA film uniaxial tension of the present invention to manufacture polarizing coating for the PVA degree of polymerization From the viewpoint of the polarizing coating of performance of shaking and excellent in te pins of durability, preferably more than 1000, more preferably more than 2000, also think More than 2500.In addition, from the viewpoint of in order to which the ease of manufacturing of the PVA film of homogeneous, draftability etc. is made, PVA polymerization Degree is preferably less than 8000, more preferably less than 6000.The degree of polymerization of PVA in this specification refers to, according to JIS K6726- The average degree of polymerization of 1994 record measure, PVA resaponifyings are asked from the inherent viscosity determined after purification in 30 DEG C of water Go out.

It is inclined from that can obtain when by the PVA film uniaxial tension of the present invention to manufacture polarizing coating for PVA saponification degree From the viewpoint of the polarizing coating of performance of shaking and excellent in te pins of durability, preferably 95 moles of more than %, more preferably 98 moles of more than %, enter One step is preferably 99 moles of more than %, particularly preferably 99.3 moles of more than %.The saponification degree of PVA in this specification refers to, phase For the construction unit of vinyl alcohol units (typically vinyl ester units) and vinyl alcohol units can be changed into by saponification Total mole number, the ratio (mole %) shared by the molal quantity of the vinyl alcohol units.PVA saponification degree can be according to JIS K6726-1994 record determines.

For the PVA film of the present invention, from the viewpoint of it can improve treatability, dyeability, draftability etc., preferably comprise Plasticizer.As plasticizer, from the viewpoint of the compatibility with PVA, preferably polyalcohol system plasticizer.As polyalcohol system The example of plasticizer, such as ethylene glycol, glycerine, propane diols, diethylene glycol (DEG), diglycerol, triethylene glycol, three contracting tetrems two can be enumerated Alcohol, trimethylolpropane etc., can use they in a kind or two or more.Wherein, the raising effect from draftability, from From the viewpoint of rationality etc., preferably using one kind or two or more in glycerine, diglycerol and ethylene glycol.

The content of plasticizer is preferably more than 1 mass parts relative to PVA100 mass parts, more preferably more than 5 mass parts, It is preferably below 30 mass parts, more preferably below 20 mass parts in addition.By the content of plasticizer more than above-mentioned lower limit, carry High dyeability, draftability.On the other hand, it can prevent PVA film from becoming excessively below the above-mentioned upper limit by the content of plasticizer Softness, improve treatability, homogeneity of cut-out etc..

For the PVA film of the present invention, the stripping peeled off from film forming apparatus is improved from its treatability and when manufacturing PVA film From the viewpoint of property etc., surfactant is preferably comprised.The species of surfactant is not particularly limited, such as can enumerate the moon Ionization series surfactant, nonionic surfactants etc..As anion system surfactant, such as carboxylic acid can be enumerated Type, sulfuric acid ester type, sulfonic acid type etc..As nonionic surfactants, such as alkyl ether type, alkyl phenyl ether can be enumerated Type, alkyl ester, alkylamide type, polypropylene glycol ether type, alkylol amide type, allyl phenyl ether type etc..The PVA film of the present invention Can be containing these surfactants a kind or two or more.

The content of surfactant is relative to PVA100 mass parts, preferably more than 0.01 mass parts, more preferably 0.05 More than mass parts, it is additionally preferred to be below 1 mass parts, more preferably below 0.3 mass parts.Existed by the content of surfactant Below the above-mentioned upper limit, can prevent surfactant the dissolution of PVA film surface, as caking the reason for, so as to treatability reduce.

For the PVA film of the present invention, as needed, it can further contain bitintability dyestuff, antioxidant, ultraviolet and inhale Receive its of agent, lubricant, colouring agent, preservative, mould inhibitor, other high-molecular compounds in addition to mentioned component, moisture etc. His composition.The PVA film of the present invention can contain the one kind or two or more of these other compositions.PVA in the PVA film of the present invention Containing ratio is preferably more than 70 mass %, more preferably more than 80 mass %, more preferably more than 90 mass %.

The manufacture method of the PVA film of the present invention is not particularly limited, and passes through following manufacture method of the invention, Ke Yishun The PVA film of the present invention is manufactured sharply, is preferable.That is, manufacture method of the invention is, along two ends of the length direction of film At least one of portion for the cut-out end, the thickness that are formed by cutting edge is strip that less than 55 μm length is more than 500m The manufacture method of PVA film, it has lower step：Using there is the large-diameter portion that is contacted with film in roll axial direction and do not contacted with film The fluted roller of minor diameter part, contact the surface of the PVA film of strip and the large-diameter portion of the fluted roller and conveyed, while in the band The position of the minor diameter part of grooved roller is alongst cut off PVA film with the circular knife of rotation, and the point of a knife angle of the circular knife is 25~50 °, the Vickers hardness of point of a knife part is more than 1500HV.Generally, slim PVA film is compared with the thick PVA film of thickness, There is roughening cut-out end face when it cuts off, but by the manufacture method of the present invention, even slim PVA film, also may be used With successfully manufacture meet present invention provide that PVA film.

In the manufacture method of the present invention fluted roller that uses roll axial direction have the large-diameter portion that is contacted with film and with film not The minor diameter part of contact.As the fluted roller it is preferable to use for example metal roller, especially with implementing chromium plating process Roller, thus the case hardness of fluted roller improve, can prevent to damage, consideration, is preferable from these in terms of etc..As Fluted roller, following fluted roller can be used：In its roll axial direction, large-diameter portion (convex portion) has at least three, in large-diameter portion and greatly Fluted roller with minor diameter part (groove, recess) (i.e. minor diameter part is with least two) between the portion of footpath.

For the diameter of the large-diameter portion of fluted roller, in terms of the conveying for carrying out PVA film well, with fluted roller well Carry out aspect, manufacturing cost of fluted roller of the cut-out of PVA film etc. to consider, preferably more than 5cm, more preferably 7.5cm More than, more preferably more than 10cm, it is additionally preferred to be below 30cm, more preferably below 25cm, be more preferably Below 20cm.By make fluted roller large-diameter portion diameter more than above-mentioned lower limit, can more uniformly cut off PVA film.It is another Aspect, by make fluted roller large-diameter portion diameter below the above-mentioned upper limit, the cost of manufacture of fluted roller can be reduced.Fluted roller In the case of multiple large-diameter portions being present, in order to which PVA film is kept into flat state while contacted with the surface of the plurality of large-diameter portion Conveyed, preferably these large-diameter portions are all identical diameters.

Width (the length of roll axial direction of the large-diameter portion of fluted roller；Each large-diameter portion in the case of multiple large-diameter portions be present Width) be more than 1mm, especially for 3~10mm, transporting from PVA films, can freely change film isolate width The aspect of size of (width after cut-out) etc. considers, is preferable.In the case that fluted roller has multiple large-diameter portions, these are big The width in footpath portion can be all identical in all large-diameter portions, or can also be that part or all is different from each other.

For the diameter of the minor diameter part of fluted roller, from prevent circular knife breakage, minor diameter part position PVA film cut-out It is preferably small relative to the diameter of adjacent large-diameter portion from the aspect of easiness of groove processing in fairness, fluted roller etc. More than 0.5cm, more preferably small more than 1cm, additionally, it is preferred that small below 2cm, more preferably small below 1.5cm.

Width (the length of roll axial direction of the minor diameter part of fluted roller；In the case of multiple minor diameter parts being present, each minor diameter part Width) be preferably it is identical or smaller with the width of adjacent large-diameter portion.In addition, for the width of minor diameter part, from circle The cut-out of aspect, suppression film that the point of a knife of knife is not contacted with fluted roller and can cut off PVA film well with stable state The considerations such as aspect for misplacing of point, relative to the wall thickness (d in Fig. 2 of the non-cone-shaped base portion in the knife edge part of circular knife Size), preferably more than 2 times, more preferably more than 5 times, more preferably less than 50 times in addition, more preferably 30 times with Under.

The circular knife used in the manufacture method of the present invention is that have in the all-round length of the discoideus body around axle There is the cutter for cutting off the blade of film.Circular knife preferably comprises metal or ceramics, specifically, can enumerate iron, iron closes Gold, high-speed tool steel, alloy tool steel, stainless steel, martensitic stain less steel, wolfram steel etc..In addition, the knife edge part of circular knife can be with It is to be handled comprising above-mentioned material and its surface by titanium nitride, titanium carbide, tungsten carbide etc..Particularly, the circular knife comprising wolfram steel is not Easily abrasion, excellent in te pins of durability, and the slickness of end face is cut off, consider from the side, be preferable.

For the Vickers hardness of at least point of a knife part of above-mentioned circular knife, from the PVA film that can successfully manufacture the present invention Consider, it is necessary to be more than 1500HV, preferably more than 1800HV.The upper limit of the Vickers hardness is not particularly limited, such as the dimension Family name's hardness can be below 2400HV.It should illustrate, in this specification, the unit of Vickers hardness is kgf/mm²。

The diameter of circular knife be [Ea's in sectional view in Fig. 2 (a) and (b) on the thickness direction of the circular knife 2 of example Length] it is preferably more than 15mm, more preferably more than 20mm, more preferably more than 40mm.By making the diameter of circular knife upper Scope is stated, suppresses the generation of abrasion, smooth cut-out end face is easily formed in the total length of the PVA film of strip.Circular knife The diameter upper limit is not particularly limited, if the diameter of circular knife is excessive, the quality increase of circular knife itself, is cut off by PVA film When, it is difficult to it is freely rotatable, and in order to prevent breakage, the wall thickness of point of a knife base portion must increase, considers in terms of these etc., circle The diameter of shape knife is preferably below 200mm, more preferably below 120mm.

The point of a knife shape of circular knife can as exemplified by Fig. 2 (a), center the both sides of point of a knife front end 3 grinding face 4, 4 ' are shrunk to coniform chevron shape (two blades), in addition can also be as exemplified by Fig. 2 (b), towards positioned at vertical The single-blade shape formed is shunk in the point of a knife front end 3 of the front end in one face 5, the coniform face 6 that another face is ground.Wherein, The point of a knife of circular knife is the chevron shape shown in Fig. 2 (a), and this is more excellent from stably being cut off PVA film, forming slickness It is preferable from the point of view of cutting off end face.

In the manufacture method of the present invention, the point of a knife angle [angle [alpha] shown in Fig. 2 (a) and (b)] of circular knife must be In the range of 25~50 °.It it is 55 μm in thickness although reason may not be clear and definite if the point of a knife angle of circular knife is less than 25 ° In the cut-out of following slim PVA film, point of a knife is easily worn away, it is difficult to continuously obtains the PVA films in manufacture strip Required cut-out end face during roller.In order to suppress the abrasion of point of a knife while good sharpness can be maintained for a long time, even if thus The length of PVA film is grown, and the degree being roughened on the overall length of film is low, forms smooth cut-out end face, therefore the knife of circular knife Wedge angle degree is preferably more than 30 °, more preferably more than 35 °.On the other hand, if the point of a knife angle of circular knife is more than 50 °, knife becomes It is blunt, it is difficult to low, the smooth cut-out end face of degree of forming face roughening.Consider from this viewpoint, the point of a knife angle of circular knife Preferably less than 45 °, more preferably less than 43 °.

Wall thickness [the wall thickness close to before being tapered into towards point of a knife nose thickness of point of a knife base portion in circular knife；Fig. 2 (a) and (b) shown in d size] be preferably more than 0.05mm, more preferably more than 0.1mm, it is additionally preferred to for 1mm with Under, more preferably below 0.5mm.By the wall thickness of point of a knife base portion more than above-mentioned lower limit, the broken of circular knife itself can be suppressed Damage.On the other hand, by the wall thickness of point of a knife base portion below the above-mentioned upper limit, the degree being roughened on the overall length of film is low, can To form smooth cut-out end face.

Length [the distance of point of a knife base portion to point of a knife front end of blade in circular knife：Fig. 2 (a) is with the e's shown in (b) Size] relative to cut-out PVA film thickness, preferably more than 1 times, more preferably more than 5 times, it is additionally preferred to for 50 times with Under, more preferably less than 45 times.By the length of blade more than above-mentioned lower limit, the cut-out end face of PVA film can be suppressed by knife Damaged caused by sharp base portion.On the other hand, the mill of knife edge part can be suppressed below the above-mentioned upper limit by the length of blade Consumption, breakage.

Make the surface of the large-diameter portion of above-mentioned fluted roller contact with the PVA film of strip to be conveyed, while in the fluted roller The position of minor diameter part when PVA film is alongst cut off by the circular knife of rotation, the circumference of the large-diameter portion of fluted roller Speed is identical with the transporting velocity of PVA film, and PVA film is conveyed on fluted roller with not loose and tight state, this for The degree of face roughening is low, to be formed for smooth cut-out end face be important.Consider from this viewpoint, by PVA film along length When spending direction cut-out, by circumference of the PVA film along fluted roller with 10~100 ゜ angles (encircling angle) [contacts shown in Fig. 3 (b) Angle beta] contact, state (state encircled) of the PVA film along fluted roller is formed, is matched somebody with somebody by the position of the minor diameter part in fluted roller The circular knife for the rotation put cuts off PVA film, and this is preferable.Now, circular knife is preferably configured in the above-mentioned center for encircling angle Or substantial middle.Thus, during cut-out, the peripheral speed of the large-diameter portion of fluted roller and the transporting velocity of PVA film become substantially It is identical, and PVA film is conveyed with tight state by fluted roller, while the rotation of the minor diameter part position by being configured at fluted roller Circular knife is cut off, therefore the cut-out end face that the degree that can be roughened with forming face is low, smooth.Consider from above-mentioned viewpoint, Encircle angle and be more preferably more than 30 °, more preferably more than 45 °, in addition, more preferably less than 98 °, more preferably Less than 95 °.

, can rotation driving be circular on one's own initiative on one side when by the circular knife of rotation, PVA film is alongst cut off Knife while cut-out PVA film, but from reduce circular knife rotary speed and PVA film transporting velocity difference, can further reduce From the viewpoint of cutting off degree of face roughening of end face etc., compared with rotation driving circular knife on one's own initiative, preferably along with PVA The conveying of film, while rotating freely circular knife, while being cut off.If rotate freely circular knife while being cut It is disconnected, then it can prevent from producing big difference between the rotary speed of circular knife and the transporting velocity of PVA film, it is possible thereby to not exert oneself PVA film is successfully cut off by force, the smaller smooth cut-out end face of the degree that forming face is roughened.For making circular knife freely revolve The mode turned is not particularly limited, such as exemplified by Fig. 2 schematic diagram (in the sectional view of the thickness direction of circular knife 2), Circular knife 2 can be fixedly installed in discoideus circular knife installation component 7, in discoideus circular knife installation component 7 Centre (center) is by the integration of rotary shaft 8 or is fixed, and extends and sets, ball axle is configured around rotary shaft 8 The bearing 9 held etc., by the way of rotary shaft 8, circular knife installation component 7 and circular knife 2 is integrally rotated freely etc..

When by the circular knife of rotation, PVA film is alongst cut off, the transporting velocity of PVA film is preferably 40m/ points Hereinafter, less than more preferably 30m/ points, more preferably 25m/ points following.By the transporting velocity below the above-mentioned upper limit, The degree of the face roughening of cut-out end face can further be reduced.On the other hand, if the transporting velocity is excessively slow, cut-out became In expending the time, productivity may be caused to reduce, therefore preferably the transporting velocity is more than 5m/ points.

When by the circular knife of rotation, PVA film is alongst cut off, the volatility of PVA film is preferably 0.1 mass % More than, more preferably more than 2 mass %, it is additionally preferred to be below 10 mass %, more preferably below 6 mass %.Pass through the volatilization Rate more than above-mentioned lower limit, will not become really up to the mark of PVA film and easily cut off.On the other hand, by the volatility above-mentioned Below the upper limit, can suppress PVA film becomes excessively soft, can further reduce the degree of the face roughening of cut-out end face.Should Give explanation, alleged " volatility of PVA film " refers in this specification, the containing ratio of the volatile ingredient included in PVA film.Make For this volatile ingredient, such as the solvent of the organic solvent used during manufacture PVA film, water etc. can be enumerated, after PVA film manufacture Moisture being inhaled into by moisture absorption in film etc..The volatility of PVA film can be by being used alone or combining two or more heating gold Belong to roller, contactless dryer etc., dry to desired value；Volatility PVA film humidifier lower than above-mentioned scope etc. is entered Row processing；Deng method be adjusted.The volatility of PVA film can be obtained by following：PVA film is configured at temperature 50 C, pressure In below power 0.1kPa vacuum drier, by dry to quality no longer reduce when rate of mass reduction obtain.

In addition, when by the circular knife of rotation, PVA film is alongst cut off, film temperature is preferably more than 10 DEG C, More preferably more than 20 DEG C, it is additionally preferred to be less than 70 DEG C, more preferably less than 60 DEG C.By the film temperature above-mentioned lower limit with On, will not become really up to the mark of PVA film and easily cut off.Moreover, it is also possible to suppress the generation of situations below：Adhere on PVA film Water droplet caused by condensation, when the PVA film after cutoff process is rolled into a roll to preserve, lump, or by water during stretching PVA film Drop attachment portion is broken.On the other hand, by the film temperature below the above-mentioned upper limit, can suppress PVA film becomes excessively Softness, it can further reduce the degree of the face roughening of cut-out end face.It should illustrate, the film temperature of PVA film can use position Point type digital radiation thermometer (such as ミノ Le タ Co. Ltd. systems " thermometer 505A " etc.) it is measured.

Can be continued the manufacturing step of PVA film using the cut-out of the length direction along PVA film of the circular knife of rotation Continuously carry out, or can also be after manufacture PVA film coils into web-like, while by PVA film from roller uncoiling while carrying out.

Manufacture method for the PVA film of cut-out is not particularly limited, and can be manufactured with previously known method, example Such as, can use by form PVA film above-mentioned PVA and further above-mentioned plasticizer as needed, surfactant and One kind or two or more in other compositions etc. is film-made stoste in liquid medium obtained by dissolving；Using containing PVA and according to The film that one kind or two or more, PVA in further plasticizer, surfactant and other compositions for needing etc. are melted Stoste manufactures.The film stoste contain plasticizer, surfactant and other compositions it is at least one kind of in the case of, preferably will These compositions equably mix.

The aforesaid liquid medium used in preparation as film stoste, such as water, dimethyl sulfoxide (DMSO), two can be enumerated NMF, dimethyl acetamide, 1-METHYLPYRROLIDONE, ethylene glycol, glycerine, propane diols, diethylene glycol (DEG), triethylene glycol, three contractings Tetraethylene glycol, trimethylolpropane, ethylenediamine, diethylenetriamines etc., can use they in a kind or two or more.Its In, from the viewpoint of the burden for environment, recyclability, preferably water.

As film-forming method when PVA film is filmed using above-mentioned film stoste, such as casting film can be enumerated Method, extrusion film method, film by wet method, gel film method etc..Can be only with a kind in these film-forming methods, can also be by 2 Combination of the above is planted to use.In these film-forming methods, casting film method, extrusion film method are good from can successfully manufacture offer Polarizing coating PVA film from the aspect of, be preferable.It can be dried as needed for film obtained by film, at heat Reason.

As the example of the specific manufacture method of the PVA film for cut-out, for example, industrially can preferably use with Under method：, will be upper using T-shaped slot die, funnel plate (ホッパープレート), I- die heads, lip coater die head etc. Film stoste is stated equably to discharge or flow on the side face of the 1st roller (either band) of the heating of the rotation positioned at most upstream side To prolong, volatile ingredient evaporation is dried in a face of the film discharged or be cast from the side face in the 1st roller (or band), Then either further it is dried on the side face of the heating roller of multiple rotations in be configured at side downstream 1 or makes it After being further dried in hot-air drying device, batched using devices for taking-up.Drying and profit using heating roller It can be implemented with the drying of hot-air drying device with appropriately combined.

The purposes of the PVA film of the present invention is not particularly limited, such as can be used for Drug packing with film, hydraulic-transfer base The various water of film, embroidery base material film, synthetic marble shaping mold release film, seed packaging film, foul collecting bag film etc. The purposes of soluble film, turn into cut-out end at least one, preferably two of two ends of the length direction along film The PVA film of the present invention, " maximum height roughness (Rz) " of the cut-out end face of the cut-out end is the cut-out below special value The degree of the face roughening of end face is extremely low, and slickness is excellent, therefore when stretching in the longitudinal direction, in the cut-out end (width of film Spend the end in direction) it is difficult to be cracked, as a result film is difficult to be broken.Consider from the side, PVA film of the invention is preferred Used as (the embryophoric membrane volume of optical film manufacture) is rolled up for manufacturing the embryophoric membrane of optical film.As this optical film, such as can To enumerate polarizing coating, phase retardation film etc., preferably polarizing coating.Such optical film for example can be real by using the film of the present invention The processing of uniaxial tension etc. is applied to manufacture.

Method when manufacturing polarizing coating using the PVA film of the present invention is not particularly limited, and can use previously known The method of meaning.As this method, such as following methods can be enumerated：Using the PVA film of the present invention, implement dyeing and single shaft is drawn Stretch, or implement uniaxial tension for the PVA film of the invention containing dyestuff.As for manufacturing the more specifically square of polarizing coating Method, the PVA film for the present invention can be enumerated, implement swelling, dyeing, uniaxial tension and further friendship as needed The method of connection processing, fixing process, drying, heat treatment etc..In this case, swelling, dyeing, crosslinking Treatment, uniaxial tension, solid The order of each processing of fixed processing etc. is not particularly limited, and can also carry out the processing of 1 or more than 2 simultaneously.In addition, also Can by 1 either each processing of more than 2 carry out for 2 times or more times.

Swelling can be by the way that PVA film be immersed in water to carry out.As the temperature for the water being immersed in when in water, preferably exist In the range of 20~40 DEG C, more preferably in the range of 22~38 DEG C, further preferably in the range of 25~35 DEG C.In addition, As the time for being impregnated in water, such as preferably in the range of 0.1~5 minute, more preferably in the range of 0.5~3 minute. Should illustrate, be immersed in water when in water and be not limited to pure water, can be dissolved with various composition the aqueous solution or water and The mixture of aqueous medium.

Dyeing can be carried out by making bitintability dyestuff be contacted with PVA film.As bitintability dyestuff, usually using iodine system Dyestuff.As the opportunity of dyeing, any stage when can be before uniaxial tension, uniaxial tension, after uniaxial tension.Generally, lead to Cross and PVA film is immersed in the solution (the particularly aqueous solution) containing iodine-potassium iodide as dye bath, dyed, at this Invention, also is adapted for using this colouring method.Iodine concentration in dye bath is preferably in the range of 0.01~0.5 mass %, iodate The concentration of potassium is preferably in the range of 0.01~10 mass %.In addition, the temperature of dye bath is preferably 20~50 DEG C, particularly preferably For 25~40 DEG C.

By implementing crosslinking Treatment to PVA film, PVA can be more efficiently prevented from carrying out during wet tensile at high temperature in water In dissolution.Consider from this viewpoint, preferably crosslinking Treatment is after the processing of contact bitintability dyestuff, the advance of uniaxial tension OK.Crosslinking Treatment can be by being immersed in the aqueous solution containing crosslinking agent to carry out by PVA film.As the crosslinking agent, can make 1 kind of the boron compound of borate with boric acid, borax etc. etc. or two or more.Crosslinking in the aqueous solution containing crosslinking agent The concentration of agent is preferably in the range of 1~15 mass %, more preferably in the range of 2~7 mass %, further preferably in 3~6 matter In the range of amount %.By the concentration of crosslinking agent in the range of 1~15 mass %, sufficient draftability can be maintained.Contain friendship The aqueous solution for joining agent can the auxiliary agent containing KI etc..The temperature of the aqueous solution containing crosslinking agent is preferably in 20~50 DEG C of model In enclosing, particularly preferably in the range of 25~40 DEG C.By making the temperature in the range of 20~50 DEG C, can effectively carry out Crosslinking.

Uniaxial tension can be carried out by any one of wet tensile method or xeothermic pulling method.The situation of wet tensile method Under, it can carry out, can also be carried out in above-mentioned dye bath, in the bath of aftermentioned fixing process in the aqueous solution containing boric acid.Separately Outside, it in the case of dry stretch process, can be stretched, can also be heated while stretch under room temperature state, can be with Carried out in atmosphere using the PVA film after water suction.Wherein, preferably wet tensile method, is more preferably containing the water-soluble of boric acid Uniaxial tension is carried out in liquid.The concentration of boric acid in boric acid aqueous solution preferably in the range of 0.5~6.0 mass %, more preferably exists In the range of 1.0~5.0 mass %, particularly preferably in the range of 1.5~4.0 mass %.In addition, boric acid aqueous solution can contain KI, its concentration is preferably in the range of 0.01~10 mass %.

Draft temperature in uniaxial tension is not particularly limited, in the case of wet tensile method, preferably at 30~90 DEG C In the range of, more preferably in the range of 40~80 DEG C, particularly preferably in the range of 50~70 DEG C.In addition, xeothermic pulling method In the case of, preferably in the range of 50~180 DEG C.

In addition, the stretching ratio in uniaxial tension (in the case of carrying out uniaxial tension with multistep, each stretching ratio is multiplied Obtained by total stretching ratio) from the aspect of the polarization property of obtained polarizing coating, preferably more than 4 times, more preferably 5 times with On.The upper limit of stretching ratio is not particularly limited, in order to uniformly be stretched, preferably less than 8 times.

The direction of uniaxial tension is not particularly limited, can use strip PVA film strip direction uniaxial tension, Horizontal uniaxial tension, from the aspect of the excellent polarizing coating of polarization property is obtained, the uniaxial tension preferably in strip direction. Uniaxial tension in strip direction can change the circle between each roller by using the stretching device for possessing multiple rollers parallel to each other Circular velocity is carried out.On the other hand, horizontal uniaxial tension can be carried out using expanding type stretching machine.

In the manufacture of polarizing coating, in order that bitintability dyestuff (iodine based dye etc.) is adsorbed in PVA film securely, preferably carry out Fixing process.Fixing process can be by the way that PVA film be immersed in fixing process bath to carry out.Bathed as fixing process, can be with Use a kind or the aqueous solution of more than two kinds of the boron compound comprising boric acid, borax etc..In addition, as needed, can also be Iodine compound, metallic compound are added in fixing process bath.The concentration of boron compound in fixing process bath is preferably generally 2~ 15 mass %, particularly preferably 3~10 mass % or so., can be more firm by making the concentration in the range of 2~15 mass % Adsorb bitintability dyestuff in ground.The temperature of fixing process bath is preferably 15~60 DEG C, particularly preferably 25~40 DEG C.

Dry condition is not particularly limited, preferably in the range of 30~150 DEG C, particularly preferably at 50~140 DEG C At a temperature in the range of be dried.By being dried at a temperature of in the range of 30~150 DEG C, dimensional stability is excellent It is different, in addition, the polarizing coating that the reduction for being readily obtained the polarization property as caused by decomposing bitintability dyestuff is suppressed.

The thickness of the polarizing coating so obtained depends on thickness of PVA film for using etc., but from polarization property, treatability, From the viewpoint of durability etc., preferably less than 30 μm, more preferably less than 25 μm, more preferably less than 20 μm, especially Preferably less than 15 μm, additionally, it is preferred that for more than 1 μm, more preferably more than 2 μm, more preferably more than 4 μm are especially excellent Elect more than 6 μm as.

For polarizing coating derived above, generally it is bonded on its two sides or one side optically transparent and there is machine The diaphragm of tool intensity, used in the form of polarizer.As diaphragm, cellulose triacetate (TAC) film, cyclenes can be used Hydrocarbon polymer (COP) film, cellulose acetate-butyrate (CAB) film, acrylic acid mesentery, polyester mesentery etc..In addition, as pasting The bonding agent of conjunction, PVA systems bonding agent, urethane adhesive etc. can be enumerated, wherein PVA systems bonding agent is suitable.

Polarizer obtained as described above can be attached in glass substrate, made after the adhesive of coating acrylic acid series etc. Used for LCD parts.It is also possible to improve film etc. with phase retardation film, viewing-angle increasing film, brightness and fit.

Embodiment

Hereinafter, the present invention is specifically described by embodiment etc., but the present invention is not by following any restriction of example.

In the following examples, each physical property is evaluated in accordance with the following methods.

(1) survey of " maximum height roughness (Rz) " and " arithmetic average roughness (Ra) " of the cut-out end face of PVA film It is fixed：

The PVA film that web-like is coiled into after the length direction cut-out along film (has the PVA of cut-out end alongst Film) roller most top layer film part (particularly since cut-out start place film length direction cut off 500m after close to Part), the sample (the taking positional number 3 of sample) of the cut-out end including length 30mm is taken along the length direction of film, The optional position of the cut-out end face for the sample taken, along the length direction of film in 100 μm of length, uses キーエ Application ス Society's laser shape measuring microscope " VK-8500 " measure cut-out end face, obtains the thickness direction central portion on the cut-out end face The length direction based on film line on surface state roughness curve, according to JIS B 0601：Specified in 2001 " most The computational methods of big height roughness (Rz) " and " arithmetic average roughness (Ra) ", " maximum height of cut-out end face is calculated respectively Roughness (Rz) " and " arithmetic average roughness (Ra) ", calculate the average value of 3 positions.

It should illustrate, when cutting off beginning and interstage, the point of a knife of cutting edge do not wear away or worn away small, forming face The low smooth cut-out end face of roughening degree, therefore omit and start to batch to during roller and batching the cut-out end face of middle time point Face roughening degree measure, the time point at the end of the maximum cut-out of the abrasion for cutting edge (coils into web-like after cut-out PVA films roller most top layer film part), obtain cut-out end face " maximum height roughness (Rz) " and " arithmetic average is thick Rugosity (Ra) ", cut off the evaluation of the degree of the face roughening of end face.

(2) confirm to whether there is during PVA film stretching and fracture (stretching ratio when film is broken) occurs：

(i) confirmation whether there is the PVA film of cut-out end alongst to be broken in stretching was manufacturing originally The fracture of PVA film when during polarizing coating, must carry out, but stretch in continuously elongated operation is typically whether a few hours occur 1 Secondary frequency, it is difficult to carry out the experiment for meeting actual use, therefore evaluated by the model test of following (ii).

(ii) PVA film for coiling into web-like after the length direction cut-out along film (has cut-out alongst The PVA film of end) roller most top layer film part (particularly since cut-out start place film length direction cut-out 500m Proximate portion afterwards), as shown in figure 1, parallelly with the length direction of film, longitudinal 1 side (long side) using sample is as cutting Broken ends of fractured bone portion, taking the rectangular sample (the sample S shown in Fig. 1) of longitudinal direction × transverse direction=15cm × 10cm size, (sample is adopted Take positional number 3).It should illustrate, now, for cutting while equivalent to 3 in addition to of cut-out end, in order to be formed not There is the smooth section that face is roughened, the cutting knife changed in a manner of the cutting on every 1 side is all cut well using point of a knife (エヌティー Co. Ltd. systems " A swords "), carry out cutting operation.

(iii) the longitudinal both ends (2 horizontal edges) for the sample taken in above-mentioned (ii) are partly by sample with 1 pair of clip Clamped with clip spacing 4cm, be installed on intermittently stretching machine, by sample mass-impregnation 1 minute in 30 DEG C of water, use is water-swellable Afterwards, immediately by sample mass-impregnation in 50 DEG C of the aqueous solution of boric acid 4% after being taken out from water, dipping is after 1 minute, directly in boron Stretched in aqueous acid under the conditions of draw speed 0.15m/ minutes, clip spacing when determination sample is broken, by Following formula obtains stretching ratio during fracture, using the average value of 3 samples.

Clip spacing (cm)/4 (cm) when stretching ratio (again)=sample during fracture is broken.

(iv) as control, with taking sample in the same manner in above-mentioned (ii), from coil into web-like PVA film (have along The PVA film of the cut-out end of length direction) roller most top layer the film part (length particularly since cut-out place in film Spend direction cut-out 500m after proximate portion) width substantial middle part, parallelly with the length direction of film, adopt Take the rectangular sample (sample without cut-out end face alongst of longitudinal direction × transverse direction=15cm × 10cm size Product) (the taking positional number 3 of sample).It should illustrate, when taking the sample of (iv), in order that 4 (4, sides in length and breadth of sample Cutting end face) not generating surface be roughened and glossily formed, use point of a knife in a manner of the cutting on every 1 side is all cut well The cutting knife (エヌティー Co. Ltd. systems " A swords ") of replacing, carry out cutting operation.

(v) using the sample of the control obtained in above-mentioned (iv), in the same manner as above-mentioned (iii), drawing during fracture is obtained Multiplying power is stretched, using the average value of 3 samples.

[embodiment 1]

(1) for PVA pieces (99.9 moles of the PVA degree of polymerization 2400, saponification degree %) 100 mass parts, the mass parts of glycerine 12 are infiltrated After the mass parts of water 220, the PVA pieces after infiltration are supplied to extruder, is melted in the case where heating is pressurizeed, prepares what PVA had been melted Stoste is film-made, the film stoste is squeezed in the 1st metallic roll (95 DEG C of the surface temperature of metallic roll, the diameter 3.8m of metallic roll) After going out, further alternately surface back side is dried in 10 metallic rolls, is continuously manufactured by the PVA film manufacture of strip (20 μm of width 3m, the thickness of film).

(2) as the shearing device for cutting off PVA films, for PVA film obtained by film to be coiled into web-like The upstream side of coiler, (the metal system of fluted roller 10 exemplified by configuration diagram 3 (a)；Diameter Eb20cm, the large-diameter portion Eb of large-diameter portion Width Wa8mm；Diameter Ec19cm, the width Wb2mm of minor diameter part of minor diameter part), while in the width of fluted roller 10 The position of minor diameter part near both ends configures the twolip for being used as new product of example in the Fig. 3 (a) rotated freely by ball bearing (the Vickers hardness 1850HV of point of a knife part of circular knife 2 of type；The diameter Ea45mm of circular knife；The ゜ of point of a knife angle [alpha] 40；Point of a knife base portion Wall thickness (wall thickness close to before being tapered into towards point of a knife nose thickness) d0.3mm；The length of blade is (from point of a knife base portion To the distance of point of a knife front end) e0.85mm) it is each 1.

(3) cut what PVA film (the mass % of volatility 3 in the film) supply of manufacture in above-mentioned (1) prepared into above-mentioned (2) Disconnected device, now, PVA is 90 ゜ relative to the contact angle β (encircling angle) of the circumferential surface of fluted roller 10, with PVA film along band The state (state encircled) of a part for the circumference of grooved roller 10 contacts PVA film and the surface of the large-diameter portion of fluted roller 10, together When conveyed with 17m/ point speed, by the use of the replacing for being used as new product rotated freely by ball bearing circular knife 2 by PVA film Two end portions alongst cut off, wide 2.6m film is made, while with coiler on aluminum pipe (diameter about 15.2cm) Web-like is continuously coiled into, the rice of total length more than 500 that the both ends obtained alongst have cut-out end face (batches length More than 500 rice) PVA film.The temperature of PVA films when being cut off using the circular knife of rotation is 30 DEG C.

(4) using more than 500 meter Chang Du obtained in above-mentioned (3) the PVA film for coiling into web-like, surveyed by the above method Fixed its cuts off " maximum height roughness (Rz) " and " arithmetic average roughness (Ra) " of end face, maximum height roughness (Rz) For 0.85 μm, arithmetic average roughness (Ra) is 0.13 μm, Rz/Ra 6.8, and alongst the cut-out end face of (total length) exists More than 500m section, the degree of face roughening is extremely low, and slickness is excellent.

(5) in addition, using more than 500 meter Chang Du obtained in above-mentioned (3) the PVA film for coiling into web-like, pass through above-mentioned side Stretching ratio during method measure film fracture, is 6.1 times.On the other hand, control sample (from the width of PVA film substantially in The sample taken of centre part) stretching ratio when film is broken is also 6.1 times.

[embodiment 2]

(1) in (2) of embodiment 1, using the circular knife as new product that point of a knife angle [alpha] is 45 °, in addition, with embodiment Similarly, the rice of total length more than 500 that the both ends obtained alongst have cut-out end face (batches length for 1 (1)~(3) More than 500 rice) PVA film.

(2) using more than 500 meter Chang Du obtained in above-mentioned (1) the PVA film for coiling into web-like, surveyed by the above method Fixed its cuts off " maximum height roughness (Rz) " and " arithmetic average roughness (Ra) " of end face, maximum height roughness (Rz) For 0.98 μm, arithmetic average roughness (Ra) is 0.15 μm, Rz/Ra 6.7, and alongst the cut-out end face of (total length) exists More than 500m section, the degree of face roughening is extremely low, and slickness is excellent.

(3) in addition, using more than 500 meter Chang Du obtained in above-mentioned (1) the PVA film for coiling into web-like, pass through above-mentioned side Stretching ratio during method measure film fracture, is 6.0 times.

[embodiment 3]

(1) in (2) of embodiment 1, using the circular knife as new product that point of a knife angle [alpha] is 30 °, in addition, with embodiment Similarly, the rice of total length more than 500 that the both ends obtained alongst have cut-out end face (batches length for 1 (1)~(3) More than 500 rice) PVA film.

(2) using more than 500 meter Chang Du obtained in above-mentioned (1) the PVA film for coiling into web-like, surveyed by the above method Fixed its cuts off " maximum height roughness (Rz) " and " arithmetic average roughness (Ra) " of end face, maximum height roughness (Rz) For 1.19 μm, arithmetic average roughness (Ra) is 0.15 μm, Rz/Ra 7.8, and alongst the cut-out end face of (total length) exists More than 500m section, the degree of face roughening is extremely low, and slickness is excellent.

(3) in addition, using more than 500 meter Chang Du obtained in above-mentioned (1) the PVA film for coiling into web-like, pass through above-mentioned side Stretching ratio during method measure film fracture, is 5.9 times.

[comparative example 1]

(1) in (3) of embodiment 1, using point of a knife part Vickers hardness be below 300HV (SKS-7) the circle as new product Shape knife, in addition, in the same manner as (1)~(3) of embodiment 1, the both ends obtained alongst have cut-out end face The rice of total length more than 500 (batching the rice of length more than 500) PVA film.

(2) using more than 500 meter Chang Du obtained in above-mentioned (1) the PVA film for coiling into web-like, surveyed by the above method Fixed its cuts off " maximum height roughness (Rz) " and " arithmetic average roughness (Ra) " of end face, maximum height roughness (Rz) For 2.68 μm, arithmetic average roughness (Ra) is 0.50 μm, Rz/Ra 5.4, compared with embodiment 1~3, cuts off the face of end face The degree of roughening is high.

(3) in addition, using more than 500 meter Chang Du obtained in above-mentioned (1) the PVA film for coiling into web-like, pass through above-mentioned side Stretching ratio during method measure film fracture, is 5.6 times, is easily broken compared with embodiment 1~3, during stretching.

[comparative example 2]

(1) in (3) of embodiment 1, using the circular knife as new product that point of a knife angle [alpha] is 23 °, in addition, with embodiment Similarly, the rice of total length more than 500 that the both ends obtained alongst have cut-out end face (batches length for 1 (1)~(3) More than 500 rice) PVA film.

(2) using more than 500 meter Chang Du obtained in above-mentioned (1) the PVA film for coiling into web-like, surveyed by the above method Fixed its cuts off " maximum height roughness (Rz) " and " arithmetic average roughness (Ra) " of end face, maximum height roughness (Rz) For 3.22 μm, arithmetic average roughness (Ra) is 0.67 μm, Rz/Ra 4.8, compared with embodiment 1~3, cuts off the face of end face The degree of roughening is high.

(3) in addition, using more than 500 meter Chang Du obtained in above-mentioned (1) the PVA film for coiling into web-like, by above-mentioned Stretching ratio during method measure film fracture, is 5.6 times, is easily broken compared with embodiment 1~3, during stretching.

Result above is shown in following table.

Symbol description

1 PVA film

2 circular knifes

The point of a knife front end of 3 circular knifes

4th, the face of 4 ' grindings

5 vertical faces

The face of 6 grindings

7 circular knife installation components

8 rotary shafts

9 bearings

10 fluted rollers

The large-diameter portion of 10a fluted rollers

The minor diameter part of 10b fluted rollers

Claims

1. polyvinyl alcohol film, it is the polyvinyl alcohol film for the strip that thickness is less than 55 μm, length is more than 500m, along film Length direction two ends at least one cut-out end to be formed by cutting edge, the cut-out end face of the cut-out end Maximum height roughness (Rz) is less than 2.5 μm in more than the length 500m of film section.

2. the polyvinyl alcohol film described in claim 1, wherein, the arithmetic average roughness (Ra) for cutting off end face is in above-mentioned section Less than 0.4 μm.

3. the polyvinyl alcohol film described in claim 1 or 2, wherein, the length of film is more than 1000m.

4. the polyvinyl alcohol film described in any one of claims 1 to 3, it is the embryophoric membrane volume of optical film manufacture.

5. the polyvinyl alcohol film described in any one of Claims 1 to 4, wherein, optical film is polarizing coating.

6. the polyvinyl alcohol film described in any one of Claims 1 to 5 coils into the roller that web-like forms.

7. manufacture method, it is at least one cut-out end to be formed by cutting edge along two ends of the length direction of film The manufacture method of the polyvinyl alcohol film for the strip that portion, thickness are less than 55 μm, length is more than 500m, it has following step Suddenly：There is the large-diameter portion contacted with film and the fluted roller with the discontiguous minor diameter part of film using in roll axial direction, make strip Polyvinyl alcohol film is contacted with the surface of the large-diameter portion of the fluted roller and conveyed, while the position of the minor diameter part in the fluted roller leads to The circular knife for crossing rotation alongst cuts off polyvinyl alcohol film, and the point of a knife angle of the circular knife is 25~50 °, nose part The Vickers hardness divided is more than 1500HV.

8. the manufacture method described in claim 7, wherein, make circumference of the polyvinyl alcohol film along fluted roller with 10~100 ° of angle Degree contact.

9. the manufacture method described in claim 7 or 8, it is the polyethylene described in for any one of manufacturing claims 1~5 The manufacture method of alcohol film.