CN110050208A

CN110050208A - Liquid crystal display device, polarizer and polaroid protective film

Info

Publication number: CN110050208A
Application number: CN201780075986.0A
Authority: CN
Inventors: 早川章太; 阿部尭永; 村田浩一; 向山幸伸
Original assignee: Toyobo Co Ltd
Current assignee: Toyobo Co Ltd
Priority date: 2016-12-14
Filing date: 2017-12-14
Publication date: 2019-07-23
Anticipated expiration: 2037-12-14
Also published as: WO2018110625A1; TW202208525A; JP7156034B2; KR102216520B1; JP7396402B2; TW201831554A; TWI795086B; KR20190087619A; CN113912994A; JP2022153484A; TWI750280B; JPWO2018110625A1; CN110050208B

Abstract

It provides: in the case that member of formation, that is, polaroid protective film PET series resin film as polarizer to be used to cope with the liquid crystal display device of wide colour gamut, in the case where filming, also can inhibit the generation of rainbow spot, improve visual liquid crystal display device, polarizer, polaroid protective film.A kind of polaroid protective film, which is characterized in that it is the polaroid protective film formed by PET series resin film, and aforementioned PET series resin film meets following (1) and (2).(1) (100) face for the crystal that there is PET series resin film 3000 or more and 30000nm retardation below, (2) to be measured with X-ray diffraction is 0.70 or less relative to the degree of orientation of pellicular front.

Description

Liquid crystal display device, polarizer and polaroid protective film

Technical field

The present invention relates to liquid crystal display device, polarizer and polaroid protective films.

Background technique

Polarizer used in liquid crystal display device (LCD) is usually the structure for using 2 polaroid protective film clamping polarizing films At the polarizing film is, as polaroid protective film, mainly to use three obtained from being infected with iodine on polyvinyl alcohol (PVA) etc. Cellulose acetate (TAC) film.In recent years, the slimming of LCD is attended by, the thin layer of polarizer is gradually required.But if thus And keep the thickness of the TAC film used as protective film thinning, then enough mechanical strengths can not be obtained, in addition, it may occur that thoroughly The problem of moist deterioration.In addition, TAC film is very expensive, although it is (special as cheap substitution raw material to propose polyester film Sharp document 1~3), but there are problems that observing iris color spot.

In the case where the one-sided configuration of polarizing film has the oriented polyester films of birefringence, from back light unit or polarization The rectilinearly polarized light that piece projects polarization state when passing through polyester film can change.The light of transmission is according to the double of oriented polyester films It reflects product, that is, retardation with thickness and shows distinctive interference colours.Therefore, if not connected using cold-cathode tube, thermionic-cathode tube etc. Continuous emission spectrum then shows different transmitted intensities according to wavelength and forms the (reference: of iris color spot as light source 15 micro-optics proceedings, the 30th~31).

As solution to the problems described above is used for, propose using have as white light-emitting diode it is continuous and The white light source of wider emission spectrum as back light, and then use the oriented polyester films with constant delay amount as Polaroid protective film (patent document 4).For white light-emitting diode, there is continuous and wider hair in visible light region Penetrate spectrum.Therefore, it when being conceived to the envelope shape of interference color spectrum of the light based on transmission birefringence body, is orientated by control The retardation of polyester film, available spectrum similar with the emission spectrum of light source, it is possible thereby to inhibit rainbow spot.

Existing technical literature

Patent document

Patent document 1: Japanese Unexamined Patent Publication 2002-116320 bulletin

Patent document 2: Japanese Unexamined Patent Publication 2004-219620 bulletin

Patent document 3: Japanese Unexamined Patent Publication 2004-205773 bulletin

Patent document 4:WO2011/162198

Summary of the invention

Problems to be solved by the invention

As the back light of liquid crystal display device, be widely used all the time by be combined with blue LED and The white light-emitting diode that the light-emitting component of yttrium-aluminium-garnet system yellow fluorophor (YAG system yellow fluorophor) is formed is (white Color LED).The emission spectrum of the white light source has wider spectrum in visible light region, and luminous efficiency is also excellent, because This, it is general to be used as back light.However, using the White LED can only to reappear human eye in the liquid crystal display device of back light 20% or so color of the spectrum that can be identified.

On the other hand, it requires to improve since colour gamut in recent years expands, and develops the liquid crystal of following corresponding wide colour gamut Display device: the emission spectrum of white light source R (red), G (green), B (indigo plant) each wavelength region in, be respectively provided with clear peak Shape.Such as develop the following liquid crystal display device for coping with wide colour gamut: it uses the white light that technology of quantum dots is utilized Source；Use the fluorescence of the fluorophor and blue led by exciting light in the region of R (red), G (green) with clear glow peak The White LED light source of body mode；Various light sources such as the White LED light source of 3 wavelength modes.Technology of quantum dots is utilized White light source be back light liquid crystal display device in the case where, it is stated that the 60% of the spectrum that human eye can identify can be reappeared Above color.

These white light sources and the previous light source phase by using the white light-emitting diode of YAG system yellow fluorophor to be formed Than the half breadth at peak is narrow, using the PET series resin film with retardation as polarizer In the case where member of formation, that is, polaroid protective film use, new discovery generates rainbow spot according to the type of light source sometimes.

In addition, the hope of the further filming of polaroid protective film smartens, in this case, also require to mention Energy supply further suppresses the PET series resin film of rainbow spot when showing picture from inclined direction (polaroid protective film).

That is, project is in the present invention, provide: using PET series resin film as reply In the case where the polaroid protective film of the liquid crystal display device of wide colour gamut, in the case where making polaroid protective film filming With inhibit rainbow spot generation, polaroid protective film, comprising its polarizer and liquid crystal display device.

The solution to the problem

The inventors of the present invention's further investigation, as a result, it has been found that: PET series resin film has specific model The retardation enclosed, and (100) face of the crystal measured with X-ray diffraction is lower relative to the degree of orientation of pellicular front, it is more effective Ground inhibits rainbow spot.

The representative present invention is as described below.

Item 1.

A kind of polaroid protective film, which is characterized in that it is to be formed by PET series resin film Polaroid protective film,

Aforementioned PET series resin film meets following (1) and (2).

(1) PET series resin film has 3000nm or more and 30000nm retardation below

(2) (100) face of the crystal measured with X-ray diffraction is 0.70 or less relative to the degree of orientation of pellicular front

Item 2.

According to polaroid protective film described in item 1, wherein thin for aforementioned PET series resin The crystallite dimension of film, (- 105) face of the crystal measured on slow-axis direction isMore than.

Item 3.

A kind of polarizer is the polaroid protective film described at least one surface of polarizing film stacking item 1 or 2 and is obtained It arrives.

Item 4.

A kind of liquid crystal display device includes back light, 2 polarizers and is configured between aforementioned 2 polarizers Liquid crystal cells,

At least one of aforementioned 2 polarizers are polarizer described in item 3.

The effect of invention

If it is liquid crystal display device of the invention, polarizer and polaroid protective film, polaroid protective film will be used as PET series resin film for should in the case where the liquid crystal display device to wide colour gamut, carry out it is thin In the case where membranization, the generation for showing the rainbow spot in picture can also be inhibited.

Specific embodiment

1. polaroid protective film

PET series resin film used in polaroid protective film of the invention preferably has 3000nm or more and 30000nm retardation below (retardation in Re, face).When retardation is lower than 3000nm, as polarizing film Strong interference colours are presented in the case where protective film use, when from inclined direction, are unable to ensure good visuality.Preferably The lower limit value of retardation is 4000nm, further preferred lower limit value is 5000nm, preferred lower limit value is 6000nm.

On the other hand, the preferred 30000nm of the upper limit of retardation, the preferred upper limit are 10000nm.If significantly more than The upper limit of 30000nm is then not only substantially unable to get visual further improvement, but also the thickness of film also becomes Must be relatively thicker, the operability as industrial materials reduces, and it is not preferable.

Refringence (refractive index-fast axis direction refractive index of slow-axis direction) preferably 0.08 or more in pellicular front, more It is preferred that 0.09 or more, further preferred 0.10 or more.The upper limit of aforementioned refringence preferably 0.15 or less.From further suppressing rainbow From the perspective of spot, it is preferred that along unidirectional strong stretching, the refringence in pellicular front is larger.

It should be noted that retardation of the invention can measure the refractive index and film thickness of 2 axis directions in pellicular front Spend and find out, or KOBRA-21ADH (Oji Scientific Instruments Co., Ltd.) also can be used etc Commercially available automatic double refraction detection device and find out.The refractive index of 2 axis directions in pellicular front can use Abbe refractomecer (ATAGO Inc. system, NAR-4T, measurement wavelength 589nm) and is found out.

PET series resin film used in polaroid protective film of the invention is from inhibiting from inclining From the perspective of the rainbow spot that tilted direction is observed, it is preferred that the retardation with particular range, and surveyed with X-ray diffraction (100) face of the crystal obtained is 0.70 or less relative to the degree of orientation of pellicular front.PET series resin is thin (100) face of the crystal of film relative to pellicular front the degree of orientation preferably 0.70 or less, more preferable 0.65 or less, more preferable 0.60 with Under, more preferable 0.59 or less, further preferred 0.58 or less.Lower limit preferably 0.40.(100) face of crystal is relative to pellicular front The degree of orientation is the orientation indicated around the molecule chain direction (c-axis) of the crystal of PET series resin film Index, the value is lower, indicates that the orientation around c-axis is more random.Orientation around the c-axis is more random, observes from inclined direction Rainbow spot it is more suppressed.

(100) face of crystal is following parameter relative to the degree of orientation of pellicular front: using X-ray diffraction device (Rigaku Corporation system, RINT2100PC), using wide as the half value of axis using the slow-axis direction of the diffracted intensity measured by pole Degree, is defined as (180- half breadth)/180.Wherein, the unit of half breadth is degree.The slow-axis direction of film can be used point Son orientation is counted (Oji ScientificInstruments Co., Ltd. system, MOA-6004 type molecularly oriented meter) and is found out.It closes It is as be described hereinafter in embodiment in the details of the measurement of the degree of orientation.

In turn, it for aforementioned PET series resin film, is surveyed on slow-axis direction with X-ray diffraction The crystallite dimension in (- 105) face of the crystal obtained is preferredMore than (angstrom).The crystallite dimension in (- 105 face) of aforementioned crystal is preferredAbove, more preferablyAbove, further preferablyMore than.The upper limit is preferredButLeft and right is sufficient.

Think, the molecule chain direction (c-axis direction) of the crystal of PET series resin film is along film Slow-axis direction orientation, the crystallite dimension of the molecule chain direction (c-axis direction) of crystal is greater than specific value and reduces point of crystal Orientation around subchain axis of orientation (c-axis), to become less to be also easy to produce iris color spot.The crystallite ruler of the strand axial direction of crystal It is very little to be measured as following with the apparent crystallite dimension in (- 105) face of crystal.

The crystallite dimension in (- 105) face of the crystal measured on slow-axis direction can calculate as follows: use X-ray diffraction Device (Rigaku Corporation system, RINT2500), according to the diffracted intensity curve of the θ of the θ measured on slow-axis direction/2, Diffraction locations, actual measurement half breadth (B) for reading (- 105) face of crystal, (thank using following formula and strangle formula), with apparent crystallite ruler Very little (ACS) is calculated.X-ray used in measurement is Cu-K alpha ray, and wavelength isIt is so-called in slow axis side in the present invention The crystallite dimension in (- 105) face of the crystal measured upwards refers to, apparent crystallite dimension.(ACS=0.9 λ/(β cos θ)).Herein, λ is the wavelength of X-rayβ be by the actual measurement half breadth (B) that reads and for correction constant (b), with (B²-b²)^1/2The half breadth of calculating.It should be noted that the constant (b) for correction is to measure Si powder under identical conditions Half breadth when NIST640b.β, B, b are the value of radian.

The degree of orientation preferably 0.6 or more in the face in (- 105) face of crystal, more preferable 0.7 or more, further preferred 0.8 with On.In the face in (- 105) face of crystal the degree of orientation can be used X-ray diffraction device (Rigaku Corporation system, RINT2500 it) measures.It measures as follows: using azimuth test sample bracket to the fixed θ of θ/2, make 360 ° of sample rotates, from And obtain the distribution of the circumferencial direction of the diffracted intensity in (- 105) face of crystal.It, will be with according to the half breadth that gained is distributed The parameter that (180- half breadth)/180 define is as the degree of orientation in face.The unit of so-called half breadth is degree herein.

In order to make the strand of crystal axially along uniaxial orientation, preferably film edge is unidirectionally stretched.Generally for mentioning The degree of orientation on high draw direction, has: the method for improving stretching ratio or reducing draft temperature.In addition, tympan is carried out When being uniaxially stretched, in draw direction, thin film planar the direction vertical with draw direction, on thickness direction, generated in inside Stress is sometimes different.It is generally known that making and stretching as referred to as being uniaxially stretched free end, fixing end is uniaxially stretched It is internal in the free situation of size in the vertical direction in direction or in the case where the size in the fixed direction vertical with draw direction Stress have relatively big difference.This is because, when making to stretch the Poisson contraction that generates on the direction vertical with draw direction freely, Or caused by the difference being suppressed.In the case where common stenter cross directional stretch, end is clamped with fixture, therefore, The Poisson contraction of liquid film flow direction (MD) is restricted when cross directional stretch.Therefore, cross directional stretch direction (TD) is also generated certainly Stress on flow direction.For thickness direction, there is no limit result, it is believed that also do not produce stress.I.e., it is believed that, along draw direction The axial stress distribution of the strand of orientation is different on flow direction and thickness direction, thus the orientation in the phenyl ring face of crystal It promotes.Orientation around strand axis of orientation (c-axis) in order to reduce crystal as a result, it is preferred that keep on draw direction Stress and strain, and make to be orientated axial stress equalization.Substantially, stress does not play a role in a thickness direction, therefore, excellent Choosing reduces the stress on the direction (flow direction) vertical with draw direction.

Protective film of the invention, that is, PET series resin film can be according to common polyester film Manufacturing method and manufacture.For example, following method: making PET series resin melting, be extruded as Sheet simultaneously forms, by temperature of the obtained No yield point PET series resin more than glass transition temperature Under, stretched along longitudinal direction using the speed difference of roller, then transversely stretched using stenter, implement heat treatment.

When being specifically illustrated to the film forming condition of PET series resin film, longitudinal stretching temperature It is degree, preferably 100~130 DEG C of transverse drawing temperature, 110~125 DEG C particularly preferred.

It manufactures in the case where the film on thin-film width direction (direction TD) with slow axis, longitudinal stretching multiplying power is preferred 0.7~1.0 times.In addition, preferably 4.0~6.0 times of cross directional stretch multiplying power, it is 4.0~5.5 times more preferable, most preferably 4.5~5.5 times.

On the other hand, it manufactures in the case where the film on film longitudinal (direction MD) with slow axis, cross directional stretch multiplying power It is preferred that 1.0~3.0 times, it is 1.5~3.0 times more preferable, 2.0~3.0 times further preferred.Longitudinal stretching multiplying power preferably 4.0~6.5 Again, 5.0~6.0 times more preferable.It should be noted that manufacturing in the case where the film on film longitudinal direction with slow axis, from drop From the perspective of (100) face of low crystal is relative to the degree of orientation of pellicular front, longitudinal stretching is preferably carried out after stretching horizontally.

In order to control retardation for above range, preferably the ratio of control longitudinal stretching multiplying power and cross directional stretch multiplying power, The thickness of draft temperature, film.If the difference of stretching ratio in length and breadth is too small, become difficult to improve retardation, not preferably.

In order to increase crystal (- 105) face crystallite dimension or reduce crystal (100) face taking relative to pellicular front Xiang Du, it is preferred that increase for unidirectional stretching ratio；Draft temperature is set as higher, at this point, to fill to film application The wind speed of the mode appropriate adjustment hot wind of the heat divided.The wind speed of hot wind is 6m/ seconds preferred~15m/ seconds, 8m/ seconds more preferable~ 12m/ seconds.When applying sufficient heat to film with high magnification along unidirectionally stretching, so as to keep on draw direction Stress and strain, and it is impartial to make to be orientated axial stress, can increase the crystallite dimension in (- 105) face of crystal, or reduce The degree of orientation of (100) face of crystal relative to pellicular front.

It is preferably 150~250 DEG C for the treatment of temperature, 180~220 DEG C particularly preferred in next heat treatment.From reduction crystal (100) face relative to the degree of orientation of pellicular front from the perspective of, the treatment temperature of heat treatment the low the more preferred.On the other hand, From the viewpoint of increasing the crystallite dimension in (- 105) face of crystal, the treatment temperature of heat treatment the high the more preferred, it is therefore preferable that Consider the harmony of the two and adjusts.

It is excellent for constituting the PET series resin of PET series resin film The above are ethylene glycol terephthalates by 85 moles of % of menu body unit.Ethylene glycol terephthalate unit preferably 90 is rubbed You are % or more, more preferable 95 moles of % or more.It should be noted that may include well known sour component, two as copolymer composition Alcohol component.As PET series resin, it is therefore particularly preferred that the poly terephthalic acid second as homopolymer Diol ester.The ratio of monomeric unit can pass through¹H-NMR is measured and is confirmed.

The transparency of these resins is excellent, and thermal characteristics, mechanical property are also excellent, by stretch process, are easy to control and prolong Chi Liang.Polyethylene terephthalate it is intrinsic birefringent big, even if the thinner thickness of film, can also relatively easily obtain Big retardation is most suitable raw material.

In addition, for the purpose for the deterioration for inhibiting the optical functionals pigments such as iodine pigment, protective film of the invention is ideal It is that the light transmittance of wavelength 380nm is 20% or less.The light transmittance of 380nm is more preferable 15% or less, further preferably 10% or less, particularly preferred 5% or less.Aforementioned light transmittance is if it is 20% hereinafter, can then inhibit optical functional color Element by ultraviolet light caused by it is rotten.It should be noted that the light transmittance in the present invention is hung down with the plane of film What histogram measured upwards, spectrophotometer (such as Hitachi's U-3500 type) can be used and measure.

In order to make protective film of the invention wavelength 380nm light transmittance 20% hereinafter, it is desirable that be suitable for adjust Save the type of ultraviolet absorbing agent, the thickness of concentration and film.Ultraviolet absorbing agent used in the present invention is well known substance. As ultraviolet absorbing agent, organic system ultraviolet absorbing agent and inorganic system's ultraviolet absorbing agent can be enumerated, from the sight of the transparency Point sets out, preferably organic system ultraviolet absorbing agent.As organic system ultraviolet absorbing agent, enumerate BTA system, hexichol can be enumerated Ketone system, cyclic imide base ester system etc. and a combination thereof, but as long as the range for absorbance defined by the present invention is just no special It limits.However, from the viewpoint of durability, particularly preferred enumerate BTA system, cyclic imide base ester system.Be applied in combination 2 kinds with On ultraviolet absorbing agent in the case where, the ultraviolet light of each wavelength can be absorbed simultaneously, therefore, can further improve ultraviolet light Assimilation effect.

As benzophenone series ultraviolet absorbing agent, enumerate BTA system ultraviolet absorbing agent, acrylic ultraviolet radiation absorption Agent, for example, 2- [2'- hydroxyl -5'- (methacryloxymethyl) phenyl] -2H- benzotriazole, 2- [2'- hydroxyl Base -5'- (methacryloxyethyl) phenyl] -2H- benzotriazole, 2- [2'- hydroxyl -5'- (methacryloxy third Base) phenyl] -2H- benzotriazole, 2,2' dihydroxy 4,4' dimethoxy benzophenone, 2,2', 4,4'- tetrahydroxy hexichol first Ketone, 2,4- di-t-butyl -6- (5- chlorobenzotriazole -2- base) phenol, 2- (2'- hydroxyl -3'- tert-butyl -5'- aminomethyl phenyl) - 5- chlorobenzotriazole, 2- (5- chlorine (2H)-benzotriazole -2- base) -4- methyl -6- (tert-butyl) phenol, 2,2' methylene bis (4- (1,1,3,3- tetramethyl butyl) -6- (2H- benzotriazole -2- base) phenol etc..It is inhaled as cyclic imide base ester system's ultraviolet light Agent is received, for example, 2,2 '-(Isosorbide-5-Nitraes-phenylene) bis- (4H-3,1- benzoxazin-4-ones), 2- methyl -3,1- benzo are disliked Piperazine -4- ketone, 2- butyl -3,1- benzoxazin-4-one, 2- phenyl -3,1- benzoxazin-4-one etc..However, being not particularly limited in These.

In addition to ultraviolet absorbing agent, in the range of not interfering effect of the invention, containing each in addition to catalyst Kind additive is also preferred scheme.As additive, for example, inorganic particle, heat resistance polymeric particles, alkali are golden Belong to compound, alkaline earth metal compound, phosphorus compound, antistatic agent, photostabilizer, fire retardant, heat stabilizer, antioxidant, resist Gelling agent, surfactant etc..In addition, in order to play the high transparency, further preferably PET series resin Particle is contained substantially no in film." containing substantially no particle " refers to, such as in the case where inorganic particle, is penetrated with fluorescence X In the case where line analysis quantitative inorganic element, becomes 50ppm or less, preferably become 10ppm or less, particularly preferably become detection limit Content below.

As in PET series resin film of the invention be compounded ultraviolet absorbing agent method, Well known method can be combined and used, such as can be by using mixing extruder in advance, by dried ultraviolet radiation absorption Agent and polymer raw material are blended, and make masterbatch, the method etc. for mixing the defined masterbatch and polymer raw material when film is film-made And it is compounded.

In order to keep ultraviolet absorbing agent evenly dispersed and economically be compounded, the ultraviolet absorbing agent concentration of masterbatch at this time It is preferably set to the concentration of 5~30 mass %.Condition as production masterbatch, it is preferred that use mixing extruder, squeezing out temperature Degree is at the fusing point of PET series resin raw material or more and 290 DEG C of temperature below, with 1~15 minute It is squeezed out.At 290 DEG C or more, the decrement of ultraviolet absorbing agent is big, in addition, the viscosity reduction of masterbatch becomes larger.Find time is 1 Minute or less when, ultraviolet absorbing agent it is uniform mixing become difficult.At this point, stabilizer, tone tune can be added as needed Save agent, antistatic agent.

Present invention it is preferred that making at least 3 layers or more of film of multilayered structure, and add in the middle layer of film Add ultraviolet absorbing agent.The film of 3-tier architecture in middle layer comprising ultraviolet absorbing agent can specifically make as follows.It will The pellet of PET series resin as outer layer is individually mixed, and contains purple as middle layer The masterbatch of ultraviolet absorbers and the pellet of PET series resin are mixed with defined ratio, and dry Afterwards, supply squeezes out slabbing from the die head of slit-shaped, carries out on casting roll cooling solid to well known melting stacking extruder Change, non-stretched film is made.That is, using 2 or more extruders, 3 layers of manifold or interflow block (such as with angle-style merging part Interflow block), the film layer stacking that will be constituted the film layer of two outer layers, constitute middle layer squeezes out 3 layers of piece from nozzle, is pouring It is cooling in casting roll, non-stretched film is made.It should be noted that in invention, in order to remove the reason of becoming optics bad point, it is former High-precision filtration is carried out when foreign matter contained in the PET series resin of material, preferably progress melting extrusion. Preferably 15 μm or less of the filtering particle size (exhibits initial filtration efficiency 95%) of filter material used in the high-precision filtration of molten resin. The filtering particle size of filter material is if it exceeds 15 μm, then the removal of 20 μm or more of foreign matter is easy to become inadequate.

In turn, good with the cementability of polarizing film in order to make, it can also be to polyethylene terephthalate of the invention Based resin film implements sided corona treatment, coating processing, flame treatment etc..

In the present invention, in order to improve the cementability with polarizing film, it is preferred that in at least single side of film of the invention On (face preferably contacted with polarizing film), there is adhesive layer, the adhesive layer is with polyester resin, polyurethane resin or poly- third It is at least one kind of for principal component in olefin(e) acid resinoid.Herein, " principal component " refers to, constitutes 50 in the solid component of adhesive layer The ingredient of quality % or more.Coating fluid used in the formation of adhesive layer of the invention is preferably, and includes water-soluble or water Aqueous coating fluid in the copolymer polyester resin of dispersibility, acrylic resin and polyurethane resin, at least one kind of.As this A little coating fluids, for example, No. 3567927 bulletins of Japanese Patent No., Japanese Patent No. No. 3589232 bulletins, Japan Patents It is water-soluble disclosed in No. 4150982 No. 3589233 bulletin, No. 3900191 bulletins of Japanese Patent No., Japanese Patent No. bulletins etc. Property or water dispersible copolymer polyester resin solution, acrylic resin solution, polyurethane resin solution etc..

Adhesive layer can obtain as follows: aforementioned coating liquid is coated on to the single axle drawn membrane of non-stretched film or longitudinal direction One or two sides after, be dried with 100~150 DEG C, further transversely stretched, to obtain.Final is easy to stick The coating weight preferred administration for connecing layer is 0.05~0.20g/m².If coating weight is lower than 0.05g/m², then viscous with gained polarizing film Connecing property becomes inadequate sometimes.On the other hand, coating weight is if it exceeds 0.20g/m², then resistance to blocking reduces sometimes.At poly- pair In the case that the two sides of ethylene terephthalate based resin film is equipped with adhesive layer, the coating weight of the adhesive layer on two sides can It can also be different, can separately set within the above range with identical.

In order to assign easy slip to adhesive layer, particle is preferably added.It is 2 μm or less it is preferable to use the average grain diameter of particle Particle.The average grain diameter of particle is if it exceeds 2 μm, then particle becomes easy from coating and falls off.As containing in adhesive layer Some particles, for example, titanium oxide, barium sulfate, calcium carbonate, calcium sulfate, silica, aluminium oxide, talcum, kaolin, The inorganic particles such as clay, calcium phosphate, mica, hectorite, zirconium oxide, tungsten oxide, lithium fluoride, calcirm-fluoride, polystyrene, propylene Organic polymers system particles such as sour system, melamine series, benzocarbamidine amine system, organic silicon-type etc..They can be separately added to easily Adhesive layer can also combine two or more and add.

In addition, the method as applied coating solution, can be used well known method.For example, reverse roll is coated with Method, gravure coating process, lip rubbing method, roller brush method, spray rubbing method, air knife coating method, bar rubbing method, tubular type scraper method Deng being carried out after these methods individually being carried out or be combined.

It should be noted that the measurement of the average grain diameter of above-mentioned particle carries out by the following method.For particle, with scanning Type electron microscope (SEM) shoots photo, becomes the multiplying power of 2~5mm, measurement 300~500 with the smallest particle 1 size A particle maximum gauge (farthest away from the distance between 2 points), using its average value as average grain diameter.

The thickness of PET series resin film of the invention is arbitrary, but preferably 30~300 μm Range.Even if for the film of thickness lower than 30 μm, the also retardation of available 3000nm or more in principle.On however, In the case of stating, the anisotropy of the mechanical characteristic of film becomes significant, become easy produce fracture, breakage etc., as industrial materials Practicability be substantially reduced.The lower limit of preferred thickness is 40 μm, and the lower limit of particularly preferred thickness is 45 μm.On the other hand, The upper limit of the thickness of polaroid protective film is if it exceeds 300 μm, then the thickness of polarizer becomes blocked up, not preferably.From as inclined Shake piece protective film practicability from the perspective of, preferably 200 μm, preferably 120 μm, more preferable 100 μm of the upper limit of thickness or less, into More preferable 80 μm of one step or less, even more preferably 65 μm or less, even more preferably 60 μm or less, even more preferably 55 μm Below.

In order to inhibit the variation of retardation, it is preferred that the uneven thickness of film is small.Draft temperature, stretching ratio are to thin The uneven thickness of film affects greatly, therefore, from the viewpoint of uneven thickness, it is also preferred that the optimization of film forming condition.It is special It is not in order to improve retardation and when reducing longitudinal stretching multiplying power, vertical uneven thickness is deteriorated sometimes.Vertical uneven thickness, which exists, to be drawn Stretching in some specific range of multiplying power becomes excessively poor region, thus, it is desirable that setting film item outside this range Part.

It is the uneven thickness of film of the invention preferably 5.0% or less, further preferred 4.5% or less, still more preferably 4.0% or less, particularly preferred 3.0% or less.

For PET series resin film, retardation (Re) and thickness direction retardation amount (Rth) The ratio between (Re/Rth) preferably 0.2 or more, more preferable 0.5 or more, further preferred 0.6 or more.From inhibition from inclined direction When rainbow spot from the perspective of, it is above-mentioned more big more the more preferred than (Re/Rth).It is the upper limit preferably 2.0 or less than (Re/Rth), more excellent Select 1.8 or less.On the other hand, from the viewpoint of uneven thickness, flatness, the above-mentioned upper limit than (Re/Rth) is preferably shorter than 1.0.2 birefringent △ it should be noted that thickness direction retardation amount refers to, when indicating from film thickness direction cross-section observation Nxz (=| nx-nz |), △ Nyz (=| ny-nz |) are respectively multiplied by the average parameter of retardation obtained from film thickness d.It asks Nx, ny, nz and film thickness d (nm) out calculate the average value of (△ Nxz × d) and (△ Nyz × d), can find out thickness direction Retardation (Rth).It should be noted that nx, ny, nz can use Abbe refractomecer (ATAGO Inc. system, NAR-4T, survey The long 589nm of standing wave) and find out.

2. polarizer

Polarizer of the invention has the structure that polaroid protective film is pasted at least one surface of polarizing film, institute Stating polarizing film is obtained from being infected with iodine on polyvinyl alcohol (PVA) etc., and random polarization piece protective film is preferably the aforementioned present invention Polaroid protective film.It is preferable to use with TAC film, acrylic film, orbornene-based for the polaroid protective film of another party Film is the film free of birefringence of representative.Or polaroid protective film can be not present in another one.For being used in the present invention Polarizer, for reflection-proof, inhibit dazzle, inhibit the purpose of scratch, being coated with various hard conatings on surface is also preferred side Case.

3. liquid crystal display device

In general, liquid crystal display panel from the side opposed with back light to display image side (visible side) successively by rear Face mould block, liquid crystal cells and prior module are constituted.Below module and prior module usually by transparent substrate, be formed in the liquid crystal list The transparent conductive film of first side surface and the polarizer for being configured at its opposite side are constituted.Herein, for polarizer, in module below In, it is configured at the side opposed with back light, in front in module, is configured at the side (visible side) of display image.

Liquid crystal display device of the invention at least makees back light and the liquid crystal cells being configured between 2 polarizers For member of formation.Furthermore it is possible to be suitable for in addition other constitute, for example colour filter, lens blooming, diffusion sheet, Antireflective film etc..It is preferred that at least one polarizer in aforementioned 2 polarizers is aforementioned polarizer of the invention.

It can be the sidelight mode by light guide plate, reflecting plate etc. as member of formation as the composition of backlight, or Full run-down type mode.

As the back light of liquid crystal display device, it is not particularly limited.Such as back light can be fluorophor mode White LED (that is, the light emitting diode and fluorophor for issuing blue light or ultraviolet light of compound semiconductor has been applied in combination And issue the element of white).As fluorophor, have: the yellow fluorophor of yttrium-aluminium-garnet system, terbium aluminium garnet system Yellow fluorophor etc..

In one embodiment, back light is preferably, 400nm more than or lower than 495nm, 495nm more than or lower than The white light source of the summit of emission spectrum is respectively provided at 600nm and 600nm or more and 780nm each wavelength region below.Example It can such as enumerate: utilize the white light source of technology of quantum dots；Have respectively using by exciting light in the region of R (red), G (green) There is the White LED light source of the fluorophor of glow peak and the fluorophor mode of blue led；The White LED light source of 3 wavelength modes；Group The White LED light source of red laser is closed；And, for example, using composition formula is K₂SiF₆: Mn⁴⁺Fluoride phosphor (also referred to as " KSF ") etc. and blue led White LED light source etc..They as the liquid crystal display device for coping with wide colour gamut back light by To concern.

The configuration of the polaroid protective film of the invention with specific delays amount in liquid crystal display device be not special It limits, penetrates the inclined of light emission side (visible side) equipped with being configured at the polarizer of incident light side (light source side), liquid crystal cells and being configured at In the case where the liquid crystal display device of tabula rasa, it is preferred that be configured at the polarizing film of the incident light side of the polarizer of incident light side Protective film, and/or the polaroid protective film for penetrating light emission side for being configured at the polarizer for penetrating light emission side are by this with specific delays The polaroid protective film that the PET series resin film of amount is formed.Particularly preferred mode is such as lower section Make the polaroid protective film for penetrating light emission side for being configured at the polarizer for penetrating light emission side the gathering to benzene with specific delays amount likes: Naphthalate based resin film.PET series resin film is configured in position than that described above In the case where, sometimes change the polarizability of liquid crystal cells.High score of the invention preferably is not used at the position for needing polarizability Sub- film, it is therefore preferable that the protective film of the polarizer as such specific position uses.

Embodiment

The present invention is more specifically illustrated hereinafter, enumerating embodiment, but the present invention is not limited by the following examples, It can also be suitable for being changed and being implemented in the range of can meet purport of the invention, these are both contained in of the invention Protection scope.It should be noted that the evaluation method of the physical property in embodiment below is as described below.

(1) retardation (Re)

Retardation is the anisotropy (△ Nxy=| Nx-Ny |) and film by the refractive index of the orthogonal twin shaft on film The parameter that the product (△ Nxy × d) of thickness d (nm) defines, is to indicate optical isotropism, anisotropic standard.By with Under method find out twin shaft refractive index anisotropy (△ Nxy).Use molecularly oriented meter (Oji Scientific Instruments Co., Ltd. system, MOA-6004 type molecularly oriented meter), find out the slow-axis direction of film, with slow-axis direction with Test sample long side becomes parallel mode, the rectangle of 4cm × 2cm is cut out, as test sample.For the sample, The refractive index for finding out orthogonal twin shaft using Abbe refractomecer (ATAGO Inc. system, NAR-4T, measurement wavelength 589nm) is (slow The refractive index of axis direction: ny, the refractive index in the direction orthogonal with slow-axis direction: nx) and thickness direction refractive index (nz), will Anisotropy (△ Nxy) of the refractive index absolute value of the difference (| nx-ny |) of aforementioned twin shaft as refractive index.For the thickness of film D (nm) is measured using electric micrometer (Fine Liu off Co., system, Miritoron 1245D), is by unit conversion nm.Retardation (Re) is found out according to the product (△ Nxy × d) of the anisotropy (△ Nxy) of refractive index and the thickness d (nm) of film.

(2) thickness direction retardation amount (Rth)

Thickness direction retardation amount be 2 when indicating from film thickness direction cross-section observation birefringent △ Nxz (=| nx-nz |), △ Nyz (=| ny-nz |) is respectively multiplied by the average parameter of retardation obtained from film thickness d.Using with retardation Same method is measured, nx, ny, nz and film thickness d (nm) are found out, calculating (△ Nxz × d) is averaged with (△ Nyz × d's) Value, finds out thickness direction retardation amount (Rth).

(3) degree of orientation of (100) face of crystal relative to pellicular front

(100) face of crystal is following parameter relative to the degree of orientation of pellicular front: using X-ray diffraction device (Rigaku Corporation system, RINT2100PC), according to by the half value by the slow-axis direction for the diffracted intensity that pole measures as axis Width, with the definition of (180- half breadth)/180.X-ray used in measurement is Cu-K alpha ray, and wavelength isPole Point measurement is following to be carried out: installation can be installed on the RINT2000 angular instrument and the more purpose sample tables of pole of RINT2100PC, with Schultz bounce technique carries out.Sample is cut into the round shape of diameter 5cm, consistent with slow-axis direction and β=90 degree and 270 degree of directions Mode is installed on sample table.It should be noted that the slow-axis direction of sample uses molecularly oriented meter (Oji Scientific Instruments Co., Ltd. system, MOA-6004 type molecularly oriented meter) and find out.The details of determination condition is as follows: will Tube voltage, which is set as 40kV, tube current is set as 40mA, 2 θ fixed angles are set as 25.830 degree, dissipates vertical limitation is set as 1.2mm, diverging Slit is set as 1 degree, scatter slit is set as 7mm, reception slit is set as 7mm.In transmission measurement, it is set as α and starts angle=0 degree, α end Only angle=35 degree, α step pitch angle=5 degree.In reflection measurement, it is set as α and starts angle=25 degree, termination point=90 degree α, α Step pitch angle=5 degree.Scan method is as follows: starting angle=0 degree, termination point=360 degree β, β step pitch angle along concentric circles β =5 degree.

Hereinafter, showing the calculation method of (100) face of crystal relative to the degree of orientation of pellicular front.β obtained in measuring =0 degree is set as I (α) (25≤α≤90) with the reflection diffraction intensity curve in β=180 degree.Horizontal axis is set as α ' (when β=0 degree For α '=α, when β=180 degree is α '=180- α), the longitudinal axis be set as the diffracted intensity in each α ', to connect β=0 degree and 180 degree Under diffracted intensity curve, available diffracted intensity curve I (α ') (25≤α '≤155).At this point, the diffraction under α '=90 degree Intensity is using β=0 degree and β=180 degree average value.The straight line of the diffracted intensity under α '=25 degree and 155 degree will be connected As baseline deduction, by gained diffracted intensity curve, crystal is calculated according to (180- half breadth)/180 using half breadth The degree of orientation of (100) face relative to pellicular front.The unit of half breadth is degree.

(4) crystallite dimension in (- 105) face of crystal

The crystallite dimension in (- 105) face of the crystal in the slow-axis direction of film calculates as follows: using X-ray diffraction device (Rigaku Corporation system, RINT2500) is read according to the diffracted intensity curve of the θ of the θ measured on slow-axis direction/2 The actual measurement half breadth (B) of diffraction maximum in the diffraction locations (2 θ=42.7 degree) in (- 105) face of crystal, uses following formula (Xie Le Formula), with apparent crystallite dimension (ACS) calculating.X-ray used in measurement is Cu-K alpha ray, and wavelength isIt needs It is noted that baseline is set as: being connected to 2 θ with straight line and be the smallest point of diffracted intensity between 30 degree~42.7 degree, in 2 θ be This 2 points line of the smallest point of diffracted intensity between 42.7 degree~50 degree.(ACS=0.9 λ/(β cos θ)).Herein, λ is X-ray Wavelengthβ is by the actual measurement half breadth (B) that reads and for the constant (b) of correction, with (B²-b²)^1/2It calculates Half breadth.It should be noted that the constant (b) for correction is half when identical conditions measure Si powder NIST640b It is worth width.Herein, β, B, b are the value of radian.It should be noted that the slow-axis direction of sample uses molecularly oriented meter (Oji Scientific Instruments Co., Ltd. system, MOA-6004 type molecularly oriented meter) and find out.

(5) rainbow spot is observed

Become vertical with the orientation main shaft of film in the unilateral absorption axiss with polarizing film of the polarizing film formed by PVA and iodine Mode paste with pet film made of aftermentioned method, it is commercially available in its opposite surface mount The polarizer formed by pet film/polarizing film/TAC film is made in TAC film.Script is existed It is replaced in the polarizer for penetrating light emission side of commercially available liquid crystal display device (the BRAVIA KDL-40W920A of SONY Co. Ltd. system) It is changed to gained polarizer.It should be noted that being pasted on the polarizer of liquid crystal display device with the absorption axiss of polarizer and script The axial consistent mode of absorption and pet film become the mode of visible side, replace polarizer.Before Stating liquid crystal display device has the back light comprising the light source and quantum dot that project exciting light.Use Hamamatsu The multi-pass light splitter PMA-12 of Photonics K.K. measures the emission spectrum of the back light of the liquid crystal display device, knot Fruit observes the emission spectrum with summit near 450nm, 528nm, 630nm, the half breadth of each summit be 16nm~ 34nm.It should be noted that time for exposure when spectroscopic assay is set as 20msec.

So that the liquid crystal display device so made is displayed in white image, carries out mesh from the front of display and inclined direction Depending on observation, generation for rainbow spot is determined according to benchmark below.It should be noted that viewing angle is set as: from display The straight line of the position of eye of the picture center of device along the line of (vertical) extraction of normal direction, with connection display center and when observing Institute's angle.

◎: in the range of 0~65 degree of viewing angle, rainbow spot is not observed.

Zero: in the range of 0~65 degree of viewing angle, slightly observing rainbow spot.

×: in the range of 0~65 degree of viewing angle, observe rainbow spot.

(Production Example 1- polyester A)

It heats up to esterification reaction tank, at the time of reaching 200 DEG C, puts into 86.4 mass parts of terephthalic acid (TPA) and second two 64.6 mass parts of alcohol, investment is as 0.017 mass parts of antimony trioxide of catalyst, magnesium acetate 4 hydrate 0.064 while stirring Mass parts, 0.16 mass parts of triethylamine.Then, pressurization heating is carried out, is pressurizeed under conditions of gauge pressure 0.34MPa, 240 DEG C After esterification, esterification reaction tank is made to be restored to normal pressure, adds 0.014 mass parts of phosphoric acid.In turn, 260 were warming up to 15 minutes DEG C, add 0.012 mass parts of trimethyl phosphate.Then after 15 minutes, decentralized processing is carried out with high pressure dispersing machine, after 15 minutes, Gained esterification reaction product is transplanted in polycondensation reaction tank, carries out polycondensation reaction at 280 DEG C, under decompression.

After polycondensation reaction, it is filtered processing with the NASLON filter that 95% cut-off diameter is 5 μm, from nozzle It is extruded as strand form, cooling is carried out using the cooling water for having carried out filtration treatment (aperture: 1 μm or less) in advance, solidifies, be cut into Partical.The inherent viscosity of gained pet resin (A) is 0.62dl/g, is contained substantially no nonactive Particle and internal precipitation particle.(hereinafter abbreviated as PET (A).)

(Production Example 2- polyester B)

By ultraviolet absorbing agent (2,2 '-(1,4- phenylene) bis- (4H-3,1- benzoxazin-4-ones) 10 matter after drying Amount part, 90 mass parts of PET (A) (inherent viscosity 0.62dl/g) mixing for containing substantially no particle, using mixing extruder, Obtain the pet resin (B) containing ultraviolet absorbing agent.(hereinafter abbreviated as PET (B))

(preparation of the modified coating fluid of Production Example 3- cementability)

Ester exchange reaction and polycondensation reaction are carried out by conventional method, and preparation is as dicarboxylic acid component (relative to dicarboxyl Sour component is whole) 46 moles of % of terephthalic acid (TPA), 46 moles of % and 5- sulfoisophthalic acid sodium of M-phthalic acid, 8 moles of %, The water of the composition of (relative to diol component entirety) ethylene glycol 50 moles of % and 50 moles of % of neopentyl glycol as diol component The copolymer polyester resin of dispersibility alkali containing Sulfonic acid metal.Then, by 51.4 mass parts of water, 38 mass parts of isopropyl alcohol, positive fourth After 5 mass parts of base cellosolve, the mixing of 0.06 mass parts of nonionic surfactants, carries out heating stirring and add after reaching 77 DEG C 5 mass parts of copolymer polyester resin for entering above-mentioned water dispersible alkali containing Sulfonic acid metal continue to stir to the block disappearance of resin, will Aqueous resin dispersion liquid is cooled to room temperature, and obtains the uniform water dispersible copolymer polyester resin of 5.0 mass % of solid component concentration Liquid.In turn, make aggregation silica dioxide granule (FUJI SILYSIACHEMICAL LTD. system, SILYSIA 310) 3 mass parts It is added SILYSIA's 310 after being scattered in 50 mass parts of water, in 99.46 mass parts of Xiang Shangshu water dispersible copolymer polyester resin liquid 20 mass parts of water are added in 0.54 mass parts of aqueous dispersions while stirring, obtain the modified coating fluid of cementability.

(embodiment 1)

By PET (A) resin granular material 90 mass parts as base film middle layer raw material without containing particle and contain 10 mass parts of PET (B) resin granular material of ultraviolet absorbing agent are carried out 6 hours after being dried under reduced pressure (1Torr) with 135 DEG C, and supply is extremely Extruder 2 (II layers of middle layer use), in addition, it is by conventional method that PET (A) is dry, it is respectively fed to (I layers of outer layer of extruder 1 With outer layer III use), it is dissolved with 285 DEG C.2 kinds of polymer are used to the filter material (nominal filter fineness 10 of stainless steel sintered body respectively μm particle 95% ends) filtering, it is laminated using 2 kind of 3 laminated stream block, after being extruded as sheet from nozzle.Applied using electrostatic Casting is wrapped on 30 DEG C of surface temperature of curtain coating drum (casting drum) and is cooled and solidified, and makes non-stretched film. At this point, adjusting the discharge rate of each extruder in such a way that I layers, II layers, the ratio of III layers of thickness become 10:80:10.

It then, is 0.08g/m with the coating weight after drying by reverse roll method²Mode be coated with above-mentioned cementability is modified Liquid be applied to the non-stretched PET film it is two-sided after, dry 20 seconds at 80 DEG C.

The non-stretched film for being formed with coating layer is imported into tentering stretching-machine, while with the end of fixture clamping film Portion, while the hot wind region that the wind speed for importeding into hot air blow port with 110 DEG C of temperature is 12m/ seconds, is become with (TD) in the width direction 4.0 times, stretched as 0.7 times of mode along liquid film flow direction (MD).Then, the amplitude stretched is kept in width direction In the state of, it is heat-treated at 200 DEG C of temperature in the hot wind region that the wind speed of hot air blow port is 10m/ seconds, and then in width The relaxation processes that direction carries out 3% are spent, about 50 μm of film thickness of uniaxial orientation PET film is obtained.

(embodiment 2)

The non-stretched film made in the same manner as in Example 1 is directed into tentering stretching-machine, while by the end of film Portion is clamped with fixture, while being directed into the wind speed in hot air blow port for 10m/ seconds hot wind regions, along width with 125 DEG C of temperature Direction is stretched as 4.5 times of mode.Then, in the state that width direction keeps the amplitude stretched, at 200 DEG C of temperature Under in the wind speed of hot air blow port be that 10m/ second hot wind regions are heat-treated, and then in the relaxation of width direction progress 3% Processing, obtains about 80 μm of film thickness of uniaxial orientation PET film.

(embodiment 3)

The non-stretched film made in the same manner as in Example 1 is directed into tentering stretching-machine, while by the end of film Portion is clamped with fixture, while the hot wind region that the wind speed for being directed into hot air blow port with 120 DEG C of temperature is 12m/ seconds, along width side It is stretched to the mode as 4.5 times.Then, in the state that width direction keeps the amplitude stretched, at 200 DEG C of temperature It is heat-treated in the hot wind region that the wind speed of hot air blow port is 10m/ seconds, and then at the relaxation that width direction carries out 3% Reason, obtains about 100 μm of film thickness of uniaxial orientation PET film.

(embodiment 4)

The non-stretched film made in the same manner as in Example 1 is directed into tentering stretching-machine, while by the end of film Portion is clamped with fixture, while the hot wind region that the wind speed for being directed into hot air blow port with 130 DEG C of temperature is 9m/ seconds, along width side It is stretched to the mode as 5.5 times.Then, in the state that width direction keeps the amplitude stretched, at 200 DEG C of temperature It is heat-treated in the hot wind region that the wind speed of hot air blow port is 10m/ seconds, and then at the relaxation that width direction carries out 3% Reason, obtains about 60 μm of film thickness of uniaxial orientation PET film.

(embodiment 5)

The non-stretched film made in the same manner as in Example 1 is directed into tentering stretching-machine, while by the end of film Portion is clamped with fixture, while being directed into the wind speed in hot air blow port for 10m/ seconds hot wind regions, along width with 125 DEG C of temperature Direction is stretched as 5.0 times, streamwise as 0.9 times of mode.Then, the amplitude stretched is kept in width direction In the state of, it is heat-treated at 200 DEG C of temperature in the hot wind region that the wind speed of hot air blow port is 10m/ seconds, and then in width The relaxation processes that direction carries out 3% are spent, about 60 μm of film thickness of uniaxial orientation PET film is obtained.

(embodiment 6)

The non-stretched film made in the same manner as in Example 1 is directed into tentering stretching-machine, while by the end of film Portion is clamped with fixture, while the hot wind region that the wind speed for being directed into hot air blow port with 120 DEG C of temperature is 10m/ seconds, along width side It is stretched to the mode as 5.0 times.Then, in the state that width direction keeps the amplitude stretched, at 200 DEG C of temperature It is heat-treated in the hot wind region that the wind speed of hot air blow port is 10m/ seconds, and then at the relaxation that width direction carries out 3% Reason, obtains about 40 μm of film thickness of uniaxial orientation PET film.

(embodiment 7)

The non-stretched film made in the same manner as in Example 1 is directed into tentering stretching-machine, while by the end of film Portion is clamped with fixture, while the hot wind region that the wind speed for being directed into hot air blow port with 110 DEG C of temperature is 12m/ seconds, along width side It is stretched to the mode as 4.5 times.Then, in the state that width direction keeps the amplitude stretched, at 200 DEG C of temperature It is heat-treated in the hot wind region that the wind speed of hot air blow port is 10m/ seconds, and then at the relaxation that width direction carries out 3% Reason, obtains about 125 μm of film thickness of uniaxial orientation PET film.

(embodiment 8)

The non-stretched film made in the same manner as in Example 1 is directed into tentering stretching-machine, while by the end of film Portion is clamped with fixture, while the hot wind region that the wind speed for being directed into hot air blow port with 115 DEG C of temperature is 10m/ seconds, along width side It is stretched to the mode as 4.5 times.Then, in the state that width direction keeps the amplitude stretched, at 200 DEG C of temperature It is heat-treated in the hot wind region that the wind speed of hot air blow port is 10m/ seconds, and then at the relaxation that width direction carries out 3% Reason, obtains about 60 μm of film thickness of uniaxial orientation PET film.

(embodiment 9)

The non-stretched film made in the same manner as in Example 1 is directed into tentering stretching-machine, while by the end of film Portion is clamped with fixture, while the hot wind region that the wind speed for being directed into hot air blow port with 120 DEG C of temperature is 12m/ seconds, along width side It is stretched to the mode as 5.0 times.Then, in the state that width direction keeps the amplitude stretched, at 130 DEG C of temperature It is heat-treated in the hot wind region that the wind speed of hot air blow port is 10m/ seconds, and then at the relaxation that width direction carries out 3% Reason, obtains about 50 μm of film thickness of uniaxial orientation PET film.

(comparative example 1)

The non-stretched film made in the same manner as in Example 1 is directed into tentering stretching-machine, while by the end of film Portion is clamped with fixture, while the hot wind region that the wind speed for being directed into hot air blow port with 125 DEG C of temperature is 5m/ seconds, along width side It is stretched to the mode as 4.0 times.Then, in the state that width direction keeps the amplitude stretched, at 225 DEG C of temperature It is heat-treated in the hot wind region that the wind speed of hot air blow port is 5m/ seconds, and then at the relaxation that width direction carries out 3% Reason, obtains about 50 μm of film thickness of uniaxial orientation PET film.

(comparative example 2)

The non-stretched film made in the same manner as in Example 1 is directed into tentering stretching-machine, while by the end of film Portion is clamped with fixture, while the hot wind region that the wind speed for being directed into hot air blow port with 95 DEG C of temperature is 10m/ seconds, along width side It is stretched to the mode as 4.0 times.Then, in the state that width direction keeps the amplitude stretched, at 150 DEG C of temperature It is heat-treated in the hot wind region that the wind speed of hot air blow port is 10m/ seconds, and then at the relaxation that width direction carries out 3% Reason, obtains about 60 μm of film thickness of uniaxial orientation PET film.

(comparative example 3)

The non-stretched film made in the same manner as in Example 1 is added with heated roller group and infrared heater Heat, later using having the roller group of difference after 1.5 times of stretchings of direction of travel progress, is imported to 105 DEG C with 100 DEG C of temperature The hot wind region that wind speed to hot air blow port is 10m/ seconds, is stretched in a manner of becoming 4.0 times in the width direction.It connects , it in the wind speed of hot air blow port is 10m/ seconds at 200 DEG C of temperature in the state that width direction keeps the amplitude stretched Hot wind region is heat-treated, and then carries out 3% relaxation processes in width direction, is obtained about 50 μm of film thickness of twin shaft and is taken To PET film.

(comparative example 4)

The non-stretched film made in the same manner as in Example 1 is directed into tentering stretching-machine, while by the end of film Portion is clamped with fixture, while the hot wind region that the wind speed for being directed into hot air blow port with 90 DEG C of temperature is 10m/ seconds, along width side It is stretched to the mode as 4.0 times.Then, in the state that width direction keeps the amplitude stretched, at 200 DEG C of temperature It is heat-treated in the hot wind region that the wind speed of hot air blow port is 10m/ seconds, and then at the relaxation that width direction carries out 3% Reason, obtains about 50 μm of film thickness of uniaxial orientation PET film.

(comparative example 5)

The heated roller group of the non-stretched film made in the same manner as in Example 1 and infrared heater heating To 105 DEG C, later using having the roller group of difference after 3.5 times of stretchings of direction of travel progress, it is directed into tentering stretching-machine, While the end of film is clamped with fixture, while the hot wind area that the wind speed for being directed into hot air blow port with 130 DEG C of temperature is 10m/ seconds Domain is stretched in a manner of becoming 4.0 times in the width direction.Then, in the state that width direction keeps the amplitude stretched, At 220 DEG C of temperature in the wind speed of hot air blow port be that 10m/ seconds hot wind regions are heat-treated, so width direction into The relaxation processes of row 3% obtain about 100 μm of film thickness of Biaxially oriented PET film.

For Examples 1 to 9, the PET film of the Comparative Examples 1 to 5, by each physical property, x-ray structure parsing, rainbow spot have been carried out The result of observation is shown in table 1 below.It should be noted that the Re/Rth of PET film obtained in embodiment 2~4,6~9 is low In 1, the flatness of film is excellent.

[table 1]

Industrial availability

If it is liquid crystal display device of the invention, polarizer and polaroid protective film, polaroid protective film will be used as PET series resin film be used to cope with the liquid crystal display device of wide colour gamut in the case where, filming In the case where, the generation for showing the rainbow spot observed in picture can also be inhibited.

Claims

1. a kind of polaroid protective film, which is characterized in that it is formed by PET series resin film Polaroid protective film,

The PET series resin film meets following (1) and (2),

(1) PET series resin film has 3000nm or more and 30000nm retardation below；

(2) (100) face of the crystal measured with X-ray diffraction is 0.70 or less relative to the degree of orientation of pellicular front.

2. polaroid protective film according to claim 1, wherein for the PET series resin The crystallite dimension of film, (- 105) face of the crystal measured on slow-axis direction isMore than.

3. a kind of polarizer is that polaroid protective film of any of claims 1 or 2 is laminated at least one surface of polarizing film Obtained from.

4. a kind of liquid crystal display device includes back light, 2 polarizers and is configured between 2 polarizers Liquid crystal cells,

At least one of described 2 polarizers are polarizer as claimed in claim 3.