KR20130106420A - Vertically aligned liquid crystal display device and method for manufacturing same - Google Patents

Abstract

An object of the present invention is to provide a vertically aligned liquid crystal display device and a method of manufacturing the same, in which the color shift is reduced and the viewing angle is widened while achieving an improvement in front contrast leading to power saving. The vertically-aligned liquid crystal display device of the present invention is a display of a vertically-aligned liquid crystal cell having a backlight, a structure in which liquid crystals having negative dielectric anisotropy are sandwiched by two transparent substrates, and the vertically-aligned liquid crystal cell. A vertically oriented liquid crystal display device having polarizing plates, one on each of the surface side and the backlight side, which satisfies specific requirements.

Description

Vertically oriented liquid crystal display and its manufacturing method {VERTICALLY ALIGNED LIQUID CRYSTAL DISPLAY DEVICE AND METHOD FOR MANUFACTURING SAME}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertically-aligned liquid crystal display device and a method of manufacturing the same, in which the color shift is reduced and the viewing angle is widened while achieving an improvement in front contrast leading to power saving.

The liquid crystal display device is advantageous in that it is thinner and lighter than the CRT (Cathode Ray Tube) and can be driven at a low voltage, so that power consumption is small. Therefore, the liquid crystal display device is used for various electronic devices, such as a television, a notebook PC (personal computer), a desktop PC, a PDA (portable terminal), and a mobile telephone.

Recently, a vertical alignment type liquid crystal display device using a vertical alignment liquid crystal (liquid with anisotropy of dielectric anisotropy) (also referred to as a 'VA (Vertical Alignment) type') has been compared with a conventional TN liquid crystal display device. In view of excellent viewing angle characteristics, it has become widely used.

In recent years, in this vertically-aligned liquid crystal display device, the demand for power saving is increasing, and the high aperture ratio by minimizing a light shielding part, a color filter on array (COA), etc. is progressing.

Moreover, although the method of making the transmittance | permeability of a polarizing plate high as a means of electric power saving is proposed, when only the transmittance | permeability of a polarizing plate is raised, the problem that a polarization degree will fall and a front contrast will fall will arise.

In order to solve this, the method of suppressing polarization cancellation by the film (protective film) arrange | positioned between a polarizing film and a liquid crystal cell, such as a retardation film and a viewing angle expansion film, is used, but it cannot satisfy a request by itself.

Patent Document 1 and Non-Patent Document 1 disclose that the front contrast is increased by the configuration of the retardation film. Although these methods suggest that the front contrast can be maintained even if the transmittance of the polarizing plate is increased, the color shift becomes very large as the front contrast improvement means by these methods. Originally, although the vertically-aligned liquid crystal display device has a small color shift, it is a method of eliminating the advantages inherent in the vertically-aligned liquid crystal display device in this configuration.

In addition, in the recent manufacturing process of a liquid crystal display device, although the roll-to-panel manufacturing method which directly bonds a rolled polarizing plate instead of the method of bonding a sheet-shaped polarizing plate to a liquid crystal panel is employ | adopted, such a manufacturing method is adopted. Also, it is desired that there is no variation in optical performance between lots of polarizing plates.

In addition, in this application, the polarizing plate manufactured in the state wound by roll shape is called "roll-type polarizing plate", and what cut | disconnected by predetermined dimension in it is called "sheet-shaped polarizing plate."

Japanese Patent Laid-Open No. 2010-54736

SID 2010 Digest of Technical Papers 55.1

Disclosure of Invention The present invention has been made in view of the above problems and circumstances, and a problem to be solved is a vertically aligned liquid crystal display device and a method of manufacturing the same, in which the color shift is reduced and the viewing angle is widened while achieving an improvement in front contrast leading to power saving. To provide.

The said subject which concerns on this invention is solved by the following means.

1. A vertical alignment type liquid crystal cell having a backlight and a structure in which the dielectric anisotropy deny liquid crystal is sandwiched by two transparent substrates, and a vertical alignment type having a polarizing plate on the display surface side and the backlight side of the vertical alignment liquid crystal cell, one by one. It is a liquid crystal display device, and satisfy | fills following requirements (a)-(c), The vertically-aligned liquid crystal display device characterized by the above-mentioned.

(a) One of the transparent substrates has a thin film transistor and a color filter.

(b) The said polarizing plate has two retardation films which clamp the polarizer using polyvinyl alcohol, and the in-plane slow axis of the retardation film of the liquid crystal cell side of the said polarizing film is orthogonal to the absorption axis of the said polarizer.

(c) When the retardation film on the color filter side of one polarizing plate is the retardation film A, and the retardation film on the liquid crystal cell side of the other polarizing plate is retardation film B among the said retardation films, the measurement wavelength is 590 nm at 23 degreeC * 55% RH. The retardation values Rt in the thickness directions of the retardation films A and B measured by are referred to as Rt (A) and Rt (B), respectively, and the value of the ratio of the retardation values Rt in the thickness direction to the in-plane retardation value Ro, respectively. When Rt / Ro (A) and Rt / Ro (B) are respectively represented, the relationship represented by the following formulas 1 to 5 is satisfied.

<Formula 1>

Rt (A) <Rt (B)

<Formula 2>

70 nm <Rt (A) <130 nm

<Formula 3>

130 nm <Rt (B) <200 nm

<Equation 4>

20 nm <Rt (B) -Rt (A) <130 nm

&Lt; EMI ID =

Rt / Ro (A) <Rt / Ro (B)

[Wherein Ro and Rt are defined by the following formula.

<Formula I>

Ro = (n _x -n _y ) × d (nm)

<Formula II>

Rt = {(n _x + n _y ) / 2-n _z } × d (nm)

In the above formula, Ro represents an in-plane retardation value in the retardation film, Rt represents a retardation value in the thickness direction in the film, d represents the thickness of the retardation film, and n _x represents the maximum (ground) in the plane of the retardation film. Axial direction), n _y represents a refractive index in a direction perpendicular to the slow axis in the retardation film plane (narrow direction), n _z represents a refractive index of the retardation film in the thickness direction, and measurement conditions Is the same as above]

2. When the in-plane retardation values Ro of the retardation films A and B are Ro (A) and Ro (B), respectively, the relationship represented by the following formulas 6 to 8 is satisfied. Vertically oriented liquid crystal display device.

&Lt; EMI ID =

Ro (A) <Ro (B)

Equation (7)

40 nm <Ro (A) <90 nm

<Formula 8>

45 nm <Ro (B) <100 nm

3. Said retardation film A or retardation film B contains cellulose ester-type resin, The said vertical alignment type liquid crystal display device of 1 or 2 characterized by the above-mentioned.

4. In-plane retardation value Ro of said retardation film A and retardation value Rt of the thickness direction are adjusted by control by a draw ratio at the time of film forming of retardation film A, and also in-plane retardation value Ro and thickness of said retardation film B Retardation value Rt of the direction was adjusted by control of extending | stretching temperature and film thickness, The vertical orientation type liquid crystal display device in any one of said 1-3 characterized by the above-mentioned.

5. It is a manufacturing method of the vertical alignment liquid crystal display device which manufactures the vertical alignment liquid crystal display device in any one of said 1-4, The long roll type polarizing plate which has at least one phase difference film of the said retardation film A and the retardation film B. And a roll-to-panel manufacturing method for the liquid crystal cell. The method for manufacturing a vertically aligned liquid crystal display device.

By the said means of this invention, the vertical alignment type liquid crystal display device and its manufacturing method which made the color shift small and the viewing angle wide can be provided, achieving the improvement of the front contrast which leads to power saving.

BRIEF DESCRIPTION OF THE DRAWINGS The conceptual diagram which shows an example of a structure of the vertically-aligned (VA type) liquid crystal display device of this invention.
2 is a conceptual view showing an example of the configuration of a conventional liquid vertical alignment type (VA type) liquid crystal display device.
3 is a conceptual diagram illustrating a roll-to-panel manufacturing method.

The vertically-aligned liquid crystal display device of the present invention is a display of a vertically-aligned liquid crystal cell having a backlight, a structure in which liquid crystals having negative dielectric anisotropy are sandwiched by two transparent substrates, and the vertically-aligned liquid crystal cell. It is a vertically-aligned liquid crystal display device which has a polarizing plate one by one on the surface side and a backlight side, Comprising: It satisfy | fills said requirements (a)-(c), It is characterized by satisfy | filling Formulas 1-5. This feature is a technical feature common to the invention according to the claims of claims 1 to 5.

As an embodiment of the present invention, when the in-plane retardation values Ro of the retardation films A and B are Ro (A) and Ro (B), respectively, from the viewpoint of the effect expression of the present invention, the above formulas 6 to It is preferable that the relationship represented by 8 is satisfied. Moreover, it is preferable that the said retardation film A or the retardation film B contains cellulose ester-type resin.

In this invention, in-plane phase difference value Ro of the said retardation film A and retardation value Rt of the thickness direction are adjusted by control by a draw ratio at the time of film forming of retardation film A, and also in-plane phase difference value of the said retardation film B It is preferable that Ro and the phase difference value Rt of the thickness direction are the form adjusted by control of extending | stretching temperature and film thickness.

As a manufacturing method of the vertically-aligned liquid crystal display device which manufactures the vertically-aligned liquid crystal display device of this invention, the elongate roll type polarizing plate which has at least one retardation film of said retardation film A and retardation film B is prepared, It is preferable that it is a manufacturing method of the form joined together by the roll-to-panel manufacturing method.

EMBODIMENT OF THE INVENTION Hereinafter, the detailed content and form for implementing this invention, its component, and this invention are demonstrated. In addition, in this application, "-" uses the numerical value described before and after that by the meaning included as a lower limit and an upper limit.

(Retardation Films A and B)

In the liquid crystal display device of the present invention, the polarizing plate has two retardation films that sandwich the polarizer using polyvinyl alcohol (PVA), and the in-plane slow axis of the retardation film on the liquid crystal cell side of the polarizing film is the absorption axis of the polarizer. It is characterized by orthogonality.

Moreover, when the retardation film on the color filter side of one polarizing plate is the retardation film A, and the retardation film on the liquid crystal cell side of the other polarizing plate is retardation film B among the said retardation films, the said retardation film A measured at the measurement wavelength of 590 nm. And B, the phase difference values Rt in the thickness direction are Rt (A) and Rt (B), respectively, and the values of the ratio of the phase difference values Rt in the thickness direction to the in-plane phase difference value Ro are respectively Rt / In the case of Ro (A) and Rt / Ro (B), the relationship represented by the following formulas 1 to 5 is satisfied.

<Formula 1>

Rt (A) <Rt (B)

<Formula 2>

70 nm <Rt (A) <130 nm

<Formula 3>

130 nm <Rt (B) <200 nm

<Equation 4>

20 nm <Rt (B) -Rt (A) <130 nm

&Lt; EMI ID =

Rt / Ro (A) <Rt / Ro (B)

However, Ro and Rt are defined by the following formula.

<Formula I>

Ro = (n _x -n _y ) × d (nm)

<Formula II>

Rt = {(n _x + n _y ) / 2-n _z } × d (nm)

In said formula, Ro represents the in-plane phase difference value in retardation film, and Rt represents the phase difference value of the thickness direction in a film. Further, d denotes a thickness of a phase difference film, n _x represents the maximum (the slow axis direction), refractive index within a plane of the retardation film. n _y represents the refractive index of the direction orthogonal to the slow axis in the retardation film plane, and n _z represents the refractive index of the retardation film in the thickness direction. In addition, measurement conditions are the same as the above.

In the present invention, for the above formulas 2 to 4, more preferably, 80 nm ≤ Rt (A) ≤ 120 nm, 140 nm ≤ Rt (B) ≤ 185 nm, and 30 nm <Rt (B)-Rt (A) <120 nm.

More preferably, 85 nm? Rt (A)? 115 nm, 145 nm? Rt (B)? 170 nm, and 35 nm <Rt (B)-Rt (A) <110 nm.

Moreover, in this invention, when the in-plane phase difference values Ro of the said phase difference films A and B are Ro (A) and Ro (B), respectively, it is preferable that the relationship represented by following formula 6-formula 8 is satisfied. Do.

&Lt; EMI ID =

Ro (A) <Ro (B)

Equation (7)

40 nm <Ro (A) <90 nm

<Formula 8>

45 nm <Ro (B) <100 nm

The liquid crystal display device of the present invention uses a vertically aligned liquid crystal cell employing a color filter on array (COA) method.

As described in, for example, Japanese Patent Application Laid-Open No. 10-206888, the COA method includes a color filter integrated driving substrate in which a color filter is directly formed on a driving side substrate of a liquid crystal cell, and an opposite electrode (conductive layer). The counter substrate provided is disposed to face each other with a spacer interposed therebetween, and a liquid crystal material is enclosed in the gap. The color filter is formed on the reflective electrode, and the bonding margin can be widened at high precision to improve the yield and the aperture ratio. have.

As for the retardation film which concerns on this invention, arrangement | positioning with respect to the structure of a liquid crystal cell is very important.

In this invention, although it is necessary to arrange | position retardation film on both sides of a liquid crystal cell, about the phase difference value Rt of the thickness direction, it is necessary for the color filter side to become relatively small, and the difference is larger than 20 nm and less than 130 nm, More preferably, it is larger than 30 nm and smaller than 120 nm, More preferably, it is larger than 35 nm and smaller than 110 nm. When this value is small, the improvement of the front contrast of a liquid crystal display device cannot be expected, and when it is too large, the color shift of a liquid crystal display device will become large, especially the mixed color in the surroundings will be remarkable, and the display quality of a liquid crystal display device will be remarkable. Lowers.

In the liquid crystal display of the present invention, Rt, which is the color filter side of the retardation film (or retardation layer) used on both sides (two locations) of the liquid crystal cell, needs to be larger than 70 nm and smaller than 130 nm, and is the opposite side of the liquid crystal cell. Rt of the retardation film needs to be larger than 130 nm and smaller than 200 nm, More preferably, Rt on the color filter side is 80 nm or more and 120 nm or less, More preferably, it is 85 nm or more and 115 nm or less.

On the other hand, Rt of retardation film on the opposite side of a liquid crystal cell is 140 nm or more and 185 nm or less, More preferably, they are 145 nm or more and 170 nm or less. The retardation value of these two retardation films affects the viewing angle of a liquid crystal display device. When each phase difference value enters a desired range, the viewing angle characteristic closer to the target can be obtained more and more.

The value of Rt / Ro of the retardation film used for the both sides (two places) of a liquid crystal cell in the liquid crystal display device of this invention needs to make the color filter side of a liquid crystal cell small. When the value of Rt / Ro which is the color filter side of a liquid crystal cell becomes large, a color shift will become large and the display quality of a liquid crystal display device will fall remarkably.

In the liquid crystal display device of the present invention, Ro of the phase difference film used on both sides (two locations) of the liquid crystal cell is 40 nm <Ro <90 nm on the color filter side and 45 <Ro <100 nm on the opposite side to the color filter. It is preferable that the opposite side to a color filter is large. In particular, the opposite side to the color filter is large, and the viewing angle can be sufficiently extended by setting it to 45 nm <Ro <100 nm, and color shift can be suppressed by disposing a relatively small Ro on the color filter side.

It is preferable to make the retardation film used for both sides (two places) of a liquid crystal cell in the liquid crystal display device of this invention by the film forming method. Moreover, it is preferable to make, controlling a phase difference value at the time of film forming.

The retardation film used for the liquid crystal display device of this invention is a cellulose ester film, a polyester film, a cycloolefin film, a polycarbonate film, a polyolefin film, a polyacryl film, the mixed resin film of an acrylic resin and a cellulose ester resin, etc. Can be mentioned.

As retardation film A, the polymeric stretched film which has polycarbonate type, a cellulose type, polyethylene type, and polypropylene resin as a main component is mentioned. Especially preferably, it is a cellulose ester-type resin.

Although the retardation value control method of these retardation films, when using a cellulose ester, for example, changes in ester substitution degree, a substituent, a change of a solvent, addition of a retardation value control material, adjustment of extending | stretching conditions, etc. can be used, but this invention When used for a liquid crystal display device, the phase difference value control of the retardation film used on the color filter side is mainly performed, and control by a draw ratio is performed, and phase difference value control on the opposite side to a color filter is performed by extending | stretching temperature and film thickness control. It is more preferable. The warpage of a liquid crystal panel can be alleviated by using the retardation film which controlled the retardation value by this means in many cases. The reason for this is that the distortion remaining on the film changes by means of the phase difference value control, and the balance of the distortion is taken from both sides of the liquid crystal cell by controlling the phase difference value on the color filter side and the opposite side by the above method, thereby warping the liquid crystal cell. It is assumed that this will be alleviated.

In addition, the detail about the resin film suitable for the retardation film etc. which are used for the liquid crystal display device of this invention is mentioned later.

(Polarizer)

When using the said phase difference film which concerns on this invention as a polarizer protective film, a polarizing plate can be produced by a general method. It is preferable to form an adhesion layer on the back surface side of the retardation film which concerns on this invention, and to bond to at least one surface of the polarizer produced by immersion extending | stretching in the iodine solution.

On the other side, you may use the retardation film which concerns on this invention, or you may use another polarizer protective film. For example, commercially available cellulose ester films (e.g., Konica Minolta Tag KC8UX, KC4UX, KC5UX, KC8UY, KC4UY, KC12UR, KC8UCR-3, KC8UCR-4, KC8UCR-5, KC8UE, KC4UE, KC4FR-3, KC4FR-3) -4, KC4HR-1, KC8UY-HA, KC8UX-RHA, and above Konica Minolta Opto Co., Ltd.) and the like are preferably used.

The polarizer which is a main component of a polarizing plate is an element which passes only the light of the polarization plane of a fixed direction, and the typical polarizer currently known is a polyvinyl alcohol-type polarizing film, which is the thing which dyed iodine on the polyvinyl alcohol-type film, and 2 Some dyes are colored.

The polarizer forms a polyvinyl alcohol aqueous solution, uniaxially stretches and dyes it, or after uniaxially stretches after dyeing, the thing which carried out durability treatment with the boron compound is used preferably.

As an adhesive used for the said adhesive layer, it is preferable that the adhesive whose storage elastic modulus in 25 degreeC is 1.0x10 <^4> -1.0x10 <^9> Pa in at least one part of an adhesion layer is used, and apply | coated adhesive and bonded it Later, a curable pressure sensitive adhesive which forms a high molecular weight or crosslinked structure by various chemical reactions is preferably used.

As a specific example, curable adhesives, such as a urethane type adhesive, an epoxy type adhesive, an aqueous polymer-isocyanate type adhesive, and a thermosetting acrylic adhesive, a moisture hardening urethane adhesive, a polyether methacrylate type, an ester type methacrylate type, an oxidized type, Anaerobic adhesives, such as a polyether methacrylate, cyanoacrylate type | system | group instant adhesive, an acrylate and a peroxide type | system | group two-component type | mold adhesive etc. are mentioned.

As said adhesive, 1-component type may be sufficient, and the form which mixes and uses 2 or more liquids before use may be sufficient.

The pressure-sensitive adhesive may be a solvent type containing an organic solvent as a medium, or may be an aqueous type such as an emulsion type, a colloidal dispersion type, an aqueous solution type or the like, which is a medium containing water as a main component, or may be a solventless type. What is necessary is just to determine the density | concentration of the said adhesive liquid suitably according to the film thickness after adhesion, application | coating method, application | coating conditions, etc., and it is 0.1-50 mass% normally.

(Vertical alignment liquid crystal cell)

Although the liquid crystal display device of this invention has a vertically-aligned liquid crystal cell, As a liquid crystal cell which concerns on this invention, conventionally well-known various liquid crystal cells can be used.

However, in this invention, the dielectric anisotropy is used for the vertically-aligned liquid crystal cell of the structure by which the negative liquid crystal is clamped by two transparent substrates. In addition, one of the transparent substrates is characterized by having a thin film transistor (TFT) and a color filter. In this regard, the configuration of the liquid crystal display device disclosed in Japanese Patent Laid-Open No. 2010-44362 is referred to. In addition, as a transparent substrate, conventionally well-known transparent glass or resin can be used.

A liquid crystal cell is formed by enclosing the nematic liquid crystal which has negative dielectric anisotropy between such glass substrates. As a nematic liquid crystal which has negative dielectric anisotropy, the conventionally well-known thing described in each publication, such as Unexamined-Japanese-Patent No. 2004-204133, Unexamined-Japanese-Patent No. 2004-250668, 2005-047980, etc. can be used. .

In the present invention, the liquid crystal cell has negative dielectric anisotropy between the upper and lower substrates as an example, and a nematic liquid crystal material of Δn = 0.0815, Δε = -4.5 or the like can be used.

Although the thickness d of a liquid crystal layer is not specifically limited, When using the liquid crystal of the characteristic of the said range, it can set to about 3.5 micrometers, for example.

In addition, in a vertically-aligned (VA type) liquid crystal display device, although the addition of the chiral material generally used in the TN mode liquid crystal display device is used in order to degrade dynamic response characteristics, it adds in order to reduce orientation defect. In some cases.

Moreover, when it is set as a multi-domain structure, it is advantageous to adjust the orientation of the liquid crystal molecule of the boundary region between each domain.

In addition, a "multi-domain structure" means the structure which divided | segmented one pixel of the liquid crystal display device into the several area | region. For example, in a vertically-aligned (VA type) liquid crystal display device, since the liquid crystal molecules are inclined at the time of white display, the magnitude of the birefringence of the liquid crystal molecules when observed in the inclined direction is different in the oblique direction and in the opposite direction, so that the luminance and Although a difference occurs in the color tone, a multi-domain structure is preferable because the viewing angle characteristic of luminance and color tone is improved.

Specifically, by constituting and averaging each of the pixels into two or more regions in which the initial alignment states of the liquid crystal molecules differ from each other, variations in luminance and color tone depending on the viewing angle can be reduced. In addition, similar effects are obtained even when each pixel is constituted of two or more different regions in which the alignment direction of liquid crystal molecules continuously changes in a voltage application state.

In order to obtain a viewing angle that is uniform in all directions, the number of divisions may be increased, but by setting it as 4 divisions or 8 divisions or more, a substantially uniform viewing angle is obtained. In particular, at eight divisions, the polarizing plate absorption axis can be set at any angle, which is preferable.

(Resin film base material used for polarizing plate, etc.)

As a resin film base material used for the polarizing plate etc. which concern on this invention, it is preferable to use a thermoplastic resin. Here, a "thermoplastic resin" means resin which becomes soft by heating to glass transition temperature or melting | fusing point, and can shape | mold in the target shape.

As the thermoplastic resin, general general purpose resins include cellulose ester, polyethylene (PE), high density polyethylene, medium density polyethylene, low density polyethylene, polypropylene (PP), polyvinyl chloride (PVC), polyvinylidene chloride, polystyrene (PS), Polyvinyl acetate (PVAc), Teflon (registered trademark) (polytetrafluoroethylene, PTFE), ABS resin (acrylonitrile butadiene styrene resin), AS resin, acrylic resin (PMMA), etc. It is preferable to melt suitably and to process by the method of this invention.

In addition, when strength or fragility is particularly required, polyamide (PA), nylon, polyacetal (POM), polycarbonate (PC), modified polyphenylene ether (m-PPE, modified PPE, PPO), Polybutylene terephthalate (PBT), polyethylene terephthalate (PET), glass fiber reinforced polyethylene terephthalate (GF-PET), cyclic polyolefin (COP), etc. can be used.

If higher heat deflection temperatures and longer service life are required, polyphenylene sulfide (PPS), polytetrafluoroethylene (PTFE), polysulfone, polyethersulfone, amorphous polyarylate, liquid crystal polymer, poly Ether ether ketone, thermoplastic polyimide (PI), polyamideimide (PAI) and the like can be used.

Moreover, it is possible to perform the combination of the kind of resin and molecular weight according to the use of this invention.

It is preferable that the thickness of a resin film selects an appropriate thickness suitably according to a use. Although the upper limit of thickness is not specifically limited, When film-forming by the solution film forming method, an upper limit is about 150 micrometers from a viewpoint of applicability | paintability, foaming, and solvent drying.

It is preferable that the total light transmittance of a resin base material is 90% or more, More preferably, it is 93% or more. The practical upper limit is about 99%. In order to achieve excellent transparency expressed by such a total light transmittance, it is necessary not to introduce an additive or a copolymerizing component which absorbs visible light, and to remove foreign substances in the polymer by high precision filtration, and to reduce the diffusion and absorption of light inside the film. It is valid to let.

Hereinafter, in this invention, especially preferable resin is demonstrated in detail.

<Cellulose cellulose resin>

The cellulose ester resin which can be used for the retardation film described in this invention is selected from cellulose (di, tri) acetate, cellulose propionate, cellulose butyrate, cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate phthalate, and cellulose phthalate It is preferable that it is at least 1 sort.

Among these, especially preferable cellulose esters include cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate propionate and cellulose acetate butyrate.

When the degree of substitution of the mixed fatty acid ester has an acyl group having 2 to 4 carbon atoms as a substituent, when the degree of substitution of the acetyl group is X and the degree of substitution of the propionyl group or the butyryl group is Y, It is preferable that it is a cellulose resin containing the cellulose ester which satisfy | fills X and ii simultaneously.

<Expression ⅰ>

1.5≤X + Y≤3.0

<Formula ii>

0≤X≤2.5

In addition, the cellulose ester used in the present invention preferably has a weight average molecular weight Mw / number average molecular weight Mn ratio of 1.5 to 5.5, particularly preferably 2.0 to 5.0, more preferably 2.5 to 5.0, and more. Preferably, cellulose esters of 3.0 to 5.0 are used.

Although the raw material cellulose of the cellulose ester used by this invention may be a wood pulp or a cotton linter, a wood pulp may be a conifer or a hardwood, but a conifer is more preferable. In view of peelability at the time of film forming, a cotton printer is preferably used. The cellulose esters made from these can be mixed as appropriate or used alone.

For example, the ratio of cellulose ester derived from cotton linter: cellulose ester derived from wood pulp (softwood) is 100: 0: 0, 90: 10: 0, 85: 15: 0, 50: 50: 0, 20: 80: 0, 10: 90: 0, 0: 100: 0, 0: 0: 100, 80:10:10, 85: 0: 15, and 40:30:30.

In the present invention, 1 g of cellulose ester resin is added to 20 ml of pure water (electric conductivity of 0.1 μS / cm or less, pH 6.8), and the pH is 6 to 7, when stirred at 25 ° C, 1 hr, and nitrogen atmosphere, and electrical conductivity It is preferable that it is 1-100 microS / cm.

<< Sugar ester compound >>

The present invention also includes a cellulose ester resin and an ester compound having at least one of 12 or more of pyranose structures or furanose structures and esterifying all or part of the OH groups of the structure. desirable.

As a ratio of esterification, it is preferable that it is 70% or more of the OH group which exists in a pyranose structure or a furanose structure.

As an example of the ester compound which concerns on this invention, although the following are mentioned, for example, this invention is not limited to this.

Glucose, galactose, mannose, fructose, xylose, or arabinose, lactose, sucrose, nystose, 1F-fructosyl nystose, starchiose, maltitol, lactitol, lactulose, cellobiose, Maltose, cellotriose, maltotriose, raffinose or kestoose.

In addition, genthiobiose, genthiotriose, genthiotetraose, xyltriose, galactosyl sucrose and the like can also be mentioned.

Among these compounds, compounds having both a pyranose structure and a furanose structure are particularly preferable.

As an example, sucrose, ketose, nythose, 1F-fructosyl nythose, starchiose and the like are preferable, and more preferably sucrose.

There is no restriction | limiting in particular as monocarboxylic acid used for esterifying all or one part of the OH group in a pyranose structure or furanose structure of this invention, A well-known aliphatic monocarboxylic acid and an alicyclic monocarboxylic acid And aromatic monocarboxylic acids can be used. The carboxylic acid used may be one kind or a mixture of two or more kinds.

Preferred aliphatic monocarboxylic acids include acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelagonic acid, capric acid, 2-ethyl-hexanecarboxylic acid, undecyl acid, Lauric acid, tridecyl acid, myristic acid, pentadecyl acid, palmitic acid, heptadecyl acid, stearic acid, nonadecanoic acid, arachinic acid, behenic acid, lignoseric acid, sertoic acid, heptaconic acid, Saturated fatty acids, such as montanic acid, melisic acid, and lacseric acid, unsaturated fatty acids, such as undecylenic acid, oleic acid, sorbic acid, linoleic acid, linolenic acid, arachidonic acid, octenic acid, etc. are mentioned.

As an example of a preferable alicyclic monocarboxylic acid, an acetic acid, cyclopentanecarboxylic acid, cyclohexane carboxylic acid, cyclooctane carboxylic acid, or derivatives thereof are mentioned.

Examples of preferred aromatic monocarboxylic acids include aromatic monocarboxylic acids, cinnamic acids, benzyl acids, biphenylcarboxylic acids, naphthalene carboxylic acids, and tetracarboxylic acids having an alkyl group and an alkoxy group introduced into a benzene ring of benzoic acid such as benzoic acid and toluic acid. Aromatic monocarboxylic acids having two or more benzene rings such as traline carboxylic acid, or derivatives thereof, and more specifically, xyllic acid, hemelic acid, mesitylene acid, prentylic acid, and γ. Isoduryl acid, duryl acid, mesitoic acid, α-isoduryl acid, cuminic acid, α-toluic acid, hydroatroic acid, atroic acid, hydrocinnamic acid, salicylic acid, o-anisic acid, m-anisic acid, p-anisic acid, creosote acid, o-homosalicylic acid, m-homosalicylic acid, p-homosalicylic acid, o-pyrocatechuic acid, β-resorsylic acid, vanillic acid, isovanlinic acid, beratric acid, o-berat Lactic acid, gallic acid, asaronic acid, mandelic acid, homo anise acid, homovanic acid, lake Moberatric acid, o-homoberatric acid, phthalonic acid and p-coumaric acid are mentioned, but benzoic acid is especially preferable.

The ester compound of an oligosaccharide can be applied as a compound which has 1-12 of at least 1 of a pyranose structure or furanose structure which concerns on this invention.

Since oligosaccharides are produced by applying an enzyme such as amylase to starch, sucrose, and the like, the oligosaccharides applicable to the present invention include, for example, maltooligosaccharides, isomaltooligosaccharides, fructooligosaccharides, galactooligosaccharides and xyl oligosaccharides. Can be.

In addition, the said ester compound is a compound which condensed 1 or more of 12 or more of at least 1 sort (s) of a pyranose structure or furanose structure represented by following General formula (A). However, R <_11> -R <_15> , R <_21> -R <_25> represents a C2-C22 acyl group or hydrogen atom, m and n represent the integer of 0-12, respectively, and m + n represents the integer of 1-12.

<Formula A>

It is preferable that R <_11> -R <_15> , R <_21> -R <_25> is a benzoyl group and a hydrogen atom. The benzoyl group may further have a substituent R ₂₆ (p is 0 to 5), and examples thereof include an alkyl group, an alkenyl group, an alkoxyl group, and a phenyl group, and these alkyl groups, alkenyl groups, and phenyl groups may further have a substituent. Oligosaccharides can also be produced by the same method as the ester compound according to the present invention.

Although the specific example of the ester compound which concerns on this invention is given to the following, this invention is not limited to this.

It is preferable that the cellulose ester film which concerns on this invention contains 0.5-30 mass% of the sugar ester compound which concerns on this invention in order to suppress fluctuation | variation of a phase difference value, and to stabilize display quality, Especially 5-5 It is preferable to contain 30 mass%.

<Acrylic resin>

Methacrylic resin is also contained in the acrylic resin which can be used for the resin film base material used for the retardation film, polarizing plate, etc. of this invention. Although it does not restrict | limit especially as resin, What consists of 50-99 mass% of methyl methacrylate units and 1-50 mass% of other monomeric units copolymerizable with this is preferable.

Examples of other copolymerizable monomers include alkyl methacrylates having 2 to 18 carbon atoms for alkyl, alkyl acrylates having 1 to 18 carbon atoms for alkyl, alpha, beta -unsaturated acids such as acrylic acid and methacrylic acid, maleic acid, Aromatic vinyl compounds such as unsaturated group-containing divalent carboxylic acids such as fumaric acid and itaconic acid, styrene, α-methylstyrene, and nuclear substituted styrene, α, β-unsaturated nitriles such as acrylonitrile and methacrylonitrile, and maleic anhydride Acid, maleimide, N-substituted maleimide, glutaric anhydride, etc. are mentioned, These can be used individually or in combination of 2 or more types.

Among these, methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, s-butyl acrylate, 2-ethylhexyl acrylate, etc. are preferable, and methyl acrylate and n-butyl acrylate are preferable. Especially preferably, it is used.

As an acrylic resin, a commercially available thing can also be used. For example, Delpet 60N, 80N (made by Asahi Kasei Chemicals Co., Ltd.), diamond BR52, BR80, BR83, BR85, BR88 (made by Mitsubishi Rayon), KT75 (made by Denki Kagaku Kogyo Co., Ltd.) Etc. can be mentioned.

<Cyclic olefin resin>

In this invention, it is also preferable to use cyclic olefin resin. As cyclic olefin resin, norbornene-type resin, monocyclic cyclic olefin resin, cyclic conjugated diene type resin, vinyl alicyclic hydrocarbon type resin, these hydrides, etc. are mentioned. Among these, norbornene-based resin can be preferably used because of its good transparency and moldability.

As norbornene-based resin, for example, a ring-opening polymer of a monomer having a norbornene structure or a ring-opening copolymer of a monomer having a norbornene structure and another monomer or an addition polymer of a monomer having a hydride or norbornene structure or The addition copolymer of the monomer which has a norbornene structure, and another monomer, these hydrides, etc. are mentioned.

Among these, the ring-opening (co) polymer hydride of the monomer having a norbornene structure can be particularly preferably used in view of transparency, moldability, heat resistance, low hygroscopicity, dimensional stability, light weight and the like.

Examples of the monomer having a norbornene structure include bicyclo [2.2.1] hepto-2-ene (common name: norbornene), tricyclo [4.3.0.1 ^2,5 ] deca-3,7-diene (common name: dish) Clopentadiene), 7,8-benzotricyclo [4.3.0.1 ^2,5 ] deca-3-ene (common name: methanotetrahydrofluorene), tetracyclo [4.4.0.1 ^2,5 , 1 ^7,10 ] Dodeca-3-ene (common name: tetracyclododecene) and derivatives of these compounds (for example, those having a substituent on the ring) and the like. Here, as a substituent, an alkyl group, an alkylene group, a polar group etc. are mentioned, for example. In addition, these substituents may be the same or different and may be bonded to a plurality of rings. The monomer which has a norbornene structure can be used individually by 1 type or in combination of 2 or more type.

As a kind of polar group, the atom group etc. which have a hetero atom or a hetero atom are mentioned. As a hetero atom, an oxygen atom, a nitrogen atom, a sulfur atom, a silicon atom, a halogen atom, etc. are mentioned, for example. Specific examples of the polar group include carboxyl group, carbonyloxy carbonyl group, epoxy group, hydroxy group, oxy group, ester group, silanol group, silyl group, amino group, nitrile group, sulfone group and the like.

Examples of other monomers capable of ring-opening copolymerization with a monomer having a norbornene structure include monocyclic olefins such as cyclohexene, cycloheptene and cyclooctene and derivatives thereof, and cyclic conjugated dienes such as cyclohexadiene and cycloheptadiene and derivatives thereof. Can be mentioned.

The ring-opening polymer of the monomer having a norbornene structure and the ring-opening copolymer of another monomer copolymerizable with the monomer having a norbornene structure can be obtained by (co) polymerizing the monomer in the presence of a known ring-opening polymerization catalyst.

As another monomer which can be addition-copolymerized with the monomer which has a norbornene structure, For example, C2-C20 alpha olefins, such as ethylene, propylene, 1-butene, and derivatives thereof; Cycloolefins and derivatives thereof such as cyclobutene, cyclopentene and cyclohexene; And non-conjugated dienes such as 1,4-hexadiene, 4-methyl-1,4-hexadiene, and 5-methyl-1,4-hexadiene. These monomers can be used individually by 1 type or in combination of 2 or more type. Among these, alpha-olefin is preferable and ethylene is more preferable.

The addition polymer of the monomer which has a norbornene structure, and the addition copolymer of the other monomer copolymerizable with the monomer which has a norbornene structure can be obtained by superposing | polymerizing a monomer in presence of a well-known addition polymerization catalyst.

Hydrogenated product of a ring-opening polymer of a monomer having a norbornene structure, hydrogenated product of a ring-opening copolymer of a monomer having a norbornene structure and other monomers that can be ring-opened copolymerized, hydrogenated product of an addition polymer of a monomer having a norbornene structure, and The hydrogenated substance of the addition copolymer of the monomer having a norbornene structure and other monomers copolymerizable with the addition of a known hydrogenation catalyst containing a transition metal such as nickel and palladium is added to the solution of these polymers, and the carbon- Preferably carbon unsaturated bond can be obtained by hydrogenating 90% or more.

Among the norbornene-based resins, as a repeating unit, X: bicyclo [3.3.0] octane-2,4-diyl-ethylene structure and Y: tricyclo [4.3.0.1 ^2,5 ] decane-7,9-diyl It has an ethylene structure, and content of these repeating units is 90 mass% or more with respect to the whole repeating unit of norbornene-type resin, and the ratio of the content rate of X and the content rate of Y is 100: 0 by mass ratio of X: Y. It is preferable that it is to 40:60. By using such resin, there is no dimensional change in a long term, and the retardation film (optical film) excellent in the stability of an optical characteristic can be obtained.

The molecular weight of the cyclic olefin resin used for this invention is suitably selected according to a use purpose. It is the weight average molecular weight (Mw) of polyisoprene or polystyrene conversion measured by the gel permeation chromatography using cyclohexane (toluene when a polymer resin does not melt | dissolve) as a solvent, and is 20,000-150,000 normally. Preferably it is 25,000-100,000, More preferably, it is 30,000-80,000. When the weight average molecular weight is in this range, the mechanical strength and moldability of the film are highly balanced and suitable.

What is necessary is just to select the glass transition temperature of cyclic olefin resin suitably according to a use purpose. From the standpoint of durability and stretchability, it is preferably in the range of 130 to 160 ° C, more preferably 135 to 150 ° C.

The molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of the cyclic olefin resin is 1.2 to 3.5, preferably 1.5 to 3.0, more preferably 1.8 to 2.7 from the viewpoint of relaxation time, productivity, and the like. .

As for the cyclic olefin resin used for this invention, it is preferable that the absolute value of a photoelastic coefficient is 10 * 10 <^-12> Pa <^-1> or less, It is more preferable that it is 7 * 10 <^-12> Pa <^-1> or less, It is 4 * 10 <^-12> Pa <^-1> or less Is particularly preferred. The photoelastic coefficient C is a value expressed by C = Δn / σ when birefringence is Δn and the stress is σ.

In this invention, it is preferable that cyclic olefin resin does not contain particle | grains substantially. Here, if it does not contain particle | grains substantially, even if particle | grains are added to the film which consists of cyclic olefin resin, it means that it can tolerate to the quantity which the range of the rise of the haze from an unadded state is 0.05% or less of range. In particular, since the alicyclic polyolefin resin lacks the affinity of many organic particles and inorganic particles, when the cyclic olefin resin film to which the particle | grains exceeding the said range were added is easy to generate | occur | produce a void, as a result, There is a fear that a significant rise in haze may occur.

<Polycarbonate resin>

In the present invention, various known polycarbonate resins can also be used. In this invention, it is especially preferable to use aromatic polycarbonate. There is no restriction | limiting in particular about the said aromatic polycarbonate, There will be no restriction | limiting in particular if it is an aromatic polycarbonate from which the various characteristic of a desired film is obtained.

In general, a polymer material generally referred to as polycarbonate is a polycondensation reaction used in the synthesis method thereof, and a general chain is used in which the main chain is linked by a carbonic bond. Among these, phenol derivatives, phosgene, and diphenyl are generally used. It is obtained by polycondensation from carbonates. Usually, although aromatic polycarbonate represented by the repeating unit which uses 2, 2-bis (4-hydroxyphenyl) propane called bisphenol-A as a bisphenol component is preferably selected, various bisphenol derivatives are suitably selected. By selecting, an aromatic polycarbonate copolymer can be comprised.

As such a copolymerization component, in addition to this bisphenol-A, bis (4-hydroxyphenyl) methane, 1, 1-bis (4-hydroxyphenyl) cyclohexane, 9, 9-bis (4-hydroxyphenyl) fluorene, 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, 2,2-bis (4-hydroxy Phenyl) -2-phenylethane, 2,2-bis (4-hydroxyphenyl) -1,1,1,3,3,3-hexafluoropropane, bis (4-hydroxyphenyl) diphenylmethane, Bis (4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl) sulfone, 1, 1-bis (4-hydroxyphenyl) -3, 3, 5- trimethyl cyclohexane etc. are mentioned.

It is also possible to use, in part, aromatic polyester carbonates comprising terephthalic acid and / or isophthalic acid components. By using such a structural unit in a part of the constituent components of the aromatic polycarbonate comprising bisphenol-A, the properties of the aromatic polycarbonate, for example, heat resistance and solubility, can be improved. The present invention is also effective.

If the viscosity average molecular weight of the aromatic polycarbonate used here is 10000 or more and 200000 or less, it is used preferably. The viscosity average molecular weights 20000-120000 are especially preferable. When the resin having a viscosity average molecular weight of less than 10000 is used, the mechanical strength of the film obtained may be insufficient, and when the molecular weight is 400000 or more, the viscosity of the dope becomes too large and problems arise in handling, which is not preferable. The viscosity average molecular weight can be measured by commercial high speed liquid chromatography or the like.

It is preferable that the glass transition temperature of the aromatic polycarbonate which concerns on this invention is 200 degreeC or more, in order to obtain a high heat resistant film, More preferably, it is 230 degreeC or more. These can be obtained by selecting the said copolymerization component suitably. The glass transition temperature can be measured by a DSC device (differential scanning calorimetry device), and is obtained by, for example, Seiko Denshi Kogyo Co., Ltd. product: RDC220, which is determined by a temperature rising condition of 10 ° C / min. This is the temperature at which it starts to bias.

In this invention, it is preferable that the solvent used for the dope composition containing the said aromatic polycarbonate is a mixed solvent containing 4-14 mass parts of methylene chloride and C1-C6 linear or branched aliphatic alcohol.

The amount of the linear or branched aliphatic alcohol having 1 to 6 carbon atoms is preferably 4 to 12 parts by mass. By using such a mixed solvent, the web is peeled off at a higher residual solvent concentration than in the prior art, thereby suppressing the generation of strong static electricity during web peeling, whereby the belt is damaged, the streaks, unevenness of the film, and the generation of minute scratches are prevented. It can prevent.

The type of alcohol added is limited depending on the solvent used. It is a necessary condition that alcohol and the said solvent are compatible. These may be added independently and there is no problem even if it combines two or more types. As an alcohol in this invention, the C1-C6, Preferably it is 1-4, More preferably, the chain | strand or branched aliphatic alcohol of 2-4 is preferable. Specifically, methanol, ethanol, isopropanol, tert-butanol, etc. are mentioned. Of these, ethanol, isopropanol and tert-butanol have almost equivalent effects, but methanol has a slightly lower effect. Although the reason is not clear, it is assumed that the boiling point of a solvent, ie, the ease of scattering at the time of drying, is related. Since higher alcohol further has a high boiling point, since it becomes easy to remain after film forming, it is not preferable.

The amount of alcohol added must be carefully selected. These alcohols are wholly lacking in solubility in aromatic polycarbonates and are a complete poor solvent. Therefore, it cannot add so much, and it should be made into the minimum amount from which peelability to be satisfied is obtained. As mentioned above, it is 4-14 mass parts with respect to methylene chloride, Preferably it is 4-12 mass parts. As for the amount of methylene chloride, the solubility to the polymer of the said solvent, dope stability improves that the addition amount is the range of 4-14 mass parts, and the effect of the peelability improvement becomes large.

Although this invention consists of said methylene chloride and aliphatic alcohol in a dope composition, another solvent can also be used. The other remaining solvent is not particularly limited as long as the aromatic polycarbonate is dissolved at a high concentration while being compatible with alcohol and having a low boiling point solvent. For example, as a solvent which is soluble in aromatic polycarbonate, halogen-based solvents such as chloroform, 1,2-dichloroethane, 1,1,2-trichloroethane and chlorobenzene in addition to methylene chloride, 1,3 -Ketone solvents, such as cyclic ether solvents, such as dioxolane, 1, 4- dioxane, and tetrahydrofuran, and cyclohexanone, are mentioned.

When using another solvent, there is no limitation in particular, It is good to consider the effect and to use. The effect here means the surface property improvement (leveling effect) of the film formed by the solution casting method, for example, by mixing a solvent in the range which does not sacrifice solubility or stability, evaporation rate, viscosity adjustment of a system, Crystallization inhibitory effect. What is necessary is just to determine the kind and addition amount of the solvent to mix according to the grade of these effects, and you may use 1 type, or 2 or more types as a solvent to mix.

Other solvents that are preferably used include halogen solvents such as chloroform and 1,2-dichloroethane, hydrocarbon solvents such as toluene and xylene, ketone solvents such as acetone, methyl ethyl ketone and cyclohexanone, ethyl acetate and butyl acetate Ether solvents, such as ester solvents, such as ethylene glycol dimethyl ether and methoxyethyl acetate, are mentioned.

The dope composition which concerns on this invention may be prepared by what kind of method, as a result, a transparent solution with low haze is obtained. A predetermined amount of alcohol may be added to the aromatic polycarbonate solution previously dissolved in a certain solvent, or the aromatic polycarbonate may be dissolved in a mixed solvent containing alcohol. However, as described above, since the alcohol is a poor solvent, in the method of adding the former later, there is a possibility of dope clouding due to precipitation of the polymer, so that the method of dissolving in the latter mixed solvent is preferable. .

<Polyester resin>

The polyester resin which can be used by this invention is obtained by superposing | polymerizing dicarboxylic acid and diol, and 70% or more of the dicarboxylic acid structural unit (structural unit derived from dicarboxylic acid) is an aromatic dicarboxylic acid. While being derived, 70% or more of the diol structural units (structural units derived from diol) are derived from aliphatic diols.

The ratio of the structural unit derived from aromatic dicarboxylic acid is 70% or more, Preferably it is 80% or more, More preferably, it is 90% or more.

The ratio of the structural unit derived from aliphatic diol is 70% or more, Preferably it is 80% or more, More preferably, it is 90% or more. Polyester resin may use 2 or more types together.

Examples of the aromatic dicarboxylic acid include naphthalene dicarboxylic acids such as terephthalic acid, isophthalic acid, 2,6-naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid and 2,7-naphthalene dicarboxylic acid, 4,4'-biphenyl dicarboxylic acid, 3,4'-biphenyl dicarboxylic acid, etc., and these ester forming derivatives can be illustrated.

Aliphatic dicarboxylic acids, such as adipic acid, azelaic acid, and sebacic acid, and monocarboxylic acids, such as benzoic acid, a propionic acid, butyric acid, can be used for a polyester resin in the range which does not impair the objective of this invention.

Examples of the aliphatic diols include ethylene glycol, 1,3-propylene diol, 1,4-butanediol, 1,4-cyclohexanedimethanol, 1,6-hexanediol, and these ester-forming derivatives.

As the polyester resin, monoalcohols such as butyl alcohol, hexyl alcohol and octyl alcohol, and polyhydric alcohols such as trimethylolpropane, glycerin and pentaerythritol can also be used within the scope of not impairing the object of the present invention.

The direct esterification method and the transesterification method which are well-known methods can be applied to manufacture of a polyester resin. Examples of the polycondensation catalyst used in the production of the polyester resin include known antimony compounds such as antimony trioxide and antimony pentoxide, germanium compounds such as germanium oxide, titanium compounds such as titanium acetate, and aluminum compounds such as aluminum chloride. Although it is possible, it is not limited to these.

Preferred polyester resins include polyethylene terephthalate resin, polyethylene terephthalate-isophthalate copolymer resin, polyethylene-1,4-cyclohexane dimethylene-terephthalate copolymer resin, polyethylene-2,6-naphthalenedicarbolate resin, and polyethylene- 2,6-naphthalene dicarboxylate-terephthalate copolymer resin, polyethylene-terephthalate-4,4'-biphenyl dicarboxylate resin, poly-1,3-propylene-terephthalate resin, polybutylene terephthalate Resins, polybutylene-2,6-naphthalene dicarboxylate resins, and the like.

As more preferable polyester resin, polyethylene terephthalate resin, polyethylene terephthalate-isophthalate copolymer resin, polyethylene-1, 4- cyclohexane dimethylene- terephthalate copolymer resin, polybutylene terephthalate resin, and polyethylene-2,6- Naphthalene dicarboxylate resin is mentioned.

The intrinsic viscosity of the polyester resin (value measured at 25 ° C in a phenol / 1,1,2,2-tetrachloroethane = 60/40 mass ratio mixed solvent) is preferably from 0.7 to 2.0 dl / g, more preferably Is 0.8 to 1.5 dl / g. When the intrinsic viscosity is 0.7 or more, the molecular weight of the polyester resin is sufficiently high, so that the molded article comprising the polyester resin composition obtained by using the same has the mechanical properties required as the molded article, and the transparency is good. When intrinsic viscosity is 2.0 or less, moldability becomes favorable.

(Other additives)

The thermoplastic resin base material which concerns on this invention can contain various compounds etc. as an additive according to the objective. For example, a phase difference (retardation) raise agent, a plasticizer, antioxidant, an acid trapping agent, an optical stabilizer, an ultraviolet absorber, an optically anisotropic control agent, a mat agent, an antistatic agent, a peeling agent, etc. can be contained.

The phase difference (retardation) increasing agent is preferably an aromatic compound having at least two aromatic rings. It is preferable to use an aromatic compound in the range of 0.01-20 mass parts with respect to 100 mass parts of resin. And it is preferable to use in the range of 0.05-15 mass parts, and it is more preferable to use in the range which is 0.1-10 mass parts. You may use together 2 or more types of aromatic compounds. The aromatic ring of the aromatic compound includes an aromatic hetero ring in addition to the aromatic hydrocarbon ring. It is especially preferable that an aromatic hydrocarbon ring is a 6-membered ring (that is, a benzene ring). An aromatic heterocycle is generally an unsaturated heterocycle. It is preferable that an aromatic hetero ring is a 5-membered ring, a 6-membered ring, or a 7-membered ring, and it is more preferable that it is a 5-membered ring or a 6-membered ring. Aromatic heterocycles generally have the most double bonds. As a hetero atom, a nitrogen atom, an oxygen atom, and a sulfur atom are preferable, and a nitrogen atom is especially preferable. Examples of aromatic hetero rings include furan ring, thiophene ring, pyrrole ring, oxazole ring, isoxazole ring, thiazole ring, isothiazole ring, imidazole ring, pyrazole ring, furazane ring, triazole ring, pyran ring, pyridine ring and pyri Polyazine ring, pyrimidine ring, pyrazine ring and 1,3,5-triazine ring. About these, Unexamined-Japanese-Patent No. 2004-109410, Unexamined-Japanese-Patent No. 2003-344655, Unexamined-Japanese-Patent No. 2000-275434, Unexamined-Japanese-Patent No. 2000-111914, Unexamined-Japanese-Patent No. 12-275434, etc. It is described in detail.

(Made by Matt)

It is also preferable to add microparticles | fine-particles to a thermoplastic resin base material which concerns on this invention in order to prevent a flaw or deterioration of conveyability when the produced film is handled.

As fine particles, examples of inorganic compounds include silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate and calcium phosphate Etc. can be mentioned. It is preferable that microparticles | fine-particles contain silicon from the point which becomes turbidity low, and especially silicon dioxide is preferable.

5-400 nm is preferable and, as for the average particle diameter of the primary particle of microparticles | fine-particles, 10-300 nm is more preferable. These may be contained mainly as a secondary aggregate with a particle diameter of 0.05-0.3 micrometer, It is also preferable that it is contained as a primary particle, without aggregating, if it is a particle | grain of an average particle diameter of 80-400 nm. It is preferable that it is 0.01-1 mass%, and, as for content of these microparticles | fine-particles in a film, 0.05-0.5 mass% is especially preferable. In the case of the retardation film (optical film) of the multilayer structure by a covalent smoke method, it is preferable to contain this addition amount microparticles on the surface.

The fine particles of silicon dioxide are commercially available under the trade names of, for example, Aerosol R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, and TT600 (above Nippon Aerosol Co., Ltd.).

The fine particles of zirconium oxide are commercially available under the trade names of, for example, Aerosol R976 and R811 (above Nippon Aerosol Co., Ltd.) and can be used.

As an example of resin, a silicone resin, a fluororesin, and an acrylic resin are mentioned. A silicone resin is preferable, and it is preferable to have a three-dimensional network structure especially, for example, tos perl 103, tos perl 105, tos perl 108, tos perl 120, tos perl 145, tos perl 3120 and tos perl 240 (above Toshiba). It is commercially available under the brand name of Silicone Co., Ltd., and can be used.

Among these, aerosil 200V and aerosil R972V are particularly preferably used because the effect of lowering the friction coefficient is great while keeping the haze of the retardation film (optical film) low. In the retardation film (optical film) which concerns on this invention, it is preferable that the dynamic friction coefficient of at least one surface is 0.2-1.0.

(Method for producing retardation film)

As a method of manufacturing the resin film base material which concerns on this invention as a film, manufacturing methods, such as a normal inflation method, the T-die method, the calender method, the cutting method, the casting method, the emulsion method, the hot press method, can be used, but color suppression is used. From the standpoints of suppressing foreign matter defects and suppressing optical defects such as die lines, the solution casting method and the melt casting method are preferred.

Hereinafter, the manufacturing method in the case of manufacturing the retardation film which concerns on this invention is demonstrated in detail.

<Method for producing retardation film by solution casting method>

<< organic solvent >>

When manufacturing the retardation film (optical film) which concerns on this invention by the solution casting | flow_spreading method, the organic solvent useful for forming dope can be used without limitation, if it melt | dissolves thermoplastic resins, such as a cellulose ester resin.

For example, as the chlorine organic solvent, methylene chloride, as the non-chlorine organic solvent, methyl acetate, ethyl acetate, amyl acetate, acetone, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, cyclohexanone, Ethyl formate, 2,2,2-trifluoroethanol, 2,2,3,3-hexafluoro-1-propanol, 1,3-difluoro-2-propanol, 1,1,1,3, 3,3-hexafluoro-2-methyl-2-propanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 2,2,3,3,3-pentafluoro- 1-propanol, nitroethane, ethyl lactate, lactic acid, diacetone alcohol, etc. are mentioned, Methylene chloride, methyl acetate, ethyl acetate, acetone, ethyl lactate etc. can be used preferably.

In addition to the said organic solvent, dope may contain the linear or branched aliphatic alcohol of 1-40 mass% C1-C4. When the ratio of alcohol in the dope increases, the web gels, and peeling from the metal support becomes easy, and when the ratio of alcohol is low, there is also a role of promoting dissolution of the thermoplastic resin in the non-chlorine organic solvent system.

In particular, it is preferable that a thermoplastic resin is a dope composition which melt | dissolved at least 10-45 mass% of systems in the solvent containing methylene chloride and a C1-C4 linear or branched aliphatic alcohol.

Examples of the straight chain or branched aliphatic alcohol having 1 to 4 carbon atoms include methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol and tert-butanol. Of these, ethanol is preferable in terms of dope stability, relatively low boiling point, and good drying property.

Hereinafter, the preferable film forming method of the retardation film (optical film) (henceforth simply called "film") concerning this invention is demonstrated.

1) Dissolution Process

It is a process of forming a dope by melt | dissolving a thermoplastic resin and other additives in stirring kiln in the organic solvent which mainly uses a good solvent for a thermoplastic resin, stirring.

For dissolving the thermoplastic resin, a method performed at ordinary pressure, a method performed below the boiling point of the main solvent, a method performed by pressing above the boiling point of the main solvent, Japanese Patent Laid-Open No. 9-95544, Japanese Patent Laid-Open No. 9-95557 Although various dissolution methods, such as the method performed by the cooling dissolution method as described in Unexamined-Japanese-Patent No. 9-95538, and the method performed by high pressure as described in Unexamined-Japanese-Patent No. 11-21379, can be used, Especially a main solvent The method of pressing and performing above the boiling point of is preferable.

The recycled raw material refers to a finely pulverized film, which cuts off both side portions of the film generated when forming the film, and a film raw material specified out of scratches and the like, which is also reused.

2) Flexible process

The dope is fed to a press die via a feed pump (e.g., a pressurized metering gear pump) and flexibly placed on a metal support such as an endless metal belt, for example, a stainless steel belt, or a rotating metal drum, which is fed indefinitely. It is a process to cast dope from a pressurized die slit at a position.

The pressurized die which can adjust the slit shape of the die member part of die | dye and is easy to make film thickness uniform is preferable. There exist a coat hanger die, a T die, etc. in pressurization die | dye, and all are used preferably. The surface of the metal support is mirror-finished. In order to raise a film forming speed | rate, two or more press dies may be provided on a metal support body, and dope amount may be divided | segmented and layered. Or it is also preferable to obtain the film of a laminated structure by the covalent smoke method which simultaneously casts a plurality of dope.

3) Solvent evaporation process

It is a process of heating a web (dope dope on a flexible support body, the formed dope film | membrane is called a web) on a casting support, and evaporating a solvent.

In order to evaporate the solvent, there is a method of blowing air from the web side, and / or a method of heat transfer with liquid from the back side of the support, or a method of heat transfer from the front and back by radiant heat, and the like. Do. Moreover, the method of combining these is also used preferably. It is preferable to dry the web on the support body after casting | flow_spread on a support body in 40-100 degreeC atmosphere. In order to maintain in 40-100 degreeC atmosphere, it is preferable to blow the warm air of this temperature on a web upper surface, or to heat by infrared rays or other means.

In view of surface quality, moisture permeability, and peelability, it is preferable to peel the web from the support within 30 to 120 seconds.

4) Peeling process

It is a process of peeling the web in which the solvent evaporated on the metal support body in a peeling position. The peeled web is sent to the next process.

The temperature at the peeling position on the metal support is preferably 10 to 40 ° C, more preferably 11 to 30 ° C.

In addition, although the amount of residual solvent at the time of peeling of a web on a metal support at the time of peeling is preferable to peel in the range of 50-120 mass% by the strength of dry conditions, the length of a metal support, etc. When peeling at the time point, when the web is too soft, the flatness is impaired at the time of peeling, and the amount of residual solvent at the time of peeling is determined by the balance of economic speed and quality because it is easy to generate pulling or vertical stripes due to peeling tension.

The residual solvent amount of the web is defined by the following formula.

Residual solvent amount (%) = (mass before heat treatment of web-mass after heat treatment of web) / (mass after heat treatment of web) × 100

In addition, the heat processing at the time of measuring the amount of residual solvent shows performing heat processing for 1 hour at 115 degreeC.

Although the peeling tension at the time of peeling a metal support body and a film is 196-245 N / m normally, when it is easy to enter a wrinkle at the time of peeling, it is preferable to peel by the tension of 190 N / m or less, Furthermore, it can peel Although it is preferable to peel at the minimum tension of 166.6 N / m and then to the minimum tension of 137.2 N / m, it is especially preferable to peel at the minimum tension of 100 N / m.

In this invention, it is preferable to make temperature in the peeling position on the said metal support body into -50-40 degreeC, 10-40 degreeC is more preferable, and it is most preferable to set it as 15-30 degreeC.

5) Drying and drawing process

After peeling, a web is dried using the drying apparatus which alternately passes the web through the roll arrange | positioned in multiple drying apparatuses, and / or the tenter stretching apparatus which clips and conveys both ends of a web with a clip.

Drying means generally blow hot air on both sides of the web, but there is also a means of heating microwaves instead of wind. Too rapid drying tends to impair the planarity of the finished film. It is preferable to perform drying by high temperature from about 8 mass% or less of residual solvent. Through and drying are performed in general at 40-250 degreeC. It is especially preferable to dry at 40-160 degreeC.

When using a tenter stretching apparatus, it is preferable to use the apparatus which can independently control the holding | gripping length (distance from holding start to holding end) of a film by the left and right holding means of a tenter. It is also desirable to make compartments with intentionally different temperatures in order to improve planarity in the tenter process.

It is also desirable to form a neutral zone so that each compartment does not cause interference between different temperature compartments.

Moreover, extending | stretching operation may be divided | segmented into multistep, and it is also preferable to carry out biaxial stretching in the casting | flow_spread direction and the width direction. In addition, when performing biaxial stretching, you may perform simultaneous biaxial stretching, and you may carry out in steps.

In this case, with a stage, it is also possible to perform different extending | stretching of the extending | stretching direction one by one, for example, and it is also possible to apply extending | stretching of a different direction to any one of them, dividing extending | stretching of the same direction into multiple steps. That is, the following extending steps are also possible, for example.

Stretching in the flexible direction-stretching in the width direction-stretching in the flexible direction-stretching in the flexible direction

Stretch in the width direction-Stretch in the width direction-Stretch in the flex direction-Stretch in the flex direction

In addition, simultaneous biaxial stretching also includes extending | stretching in one direction and reducing the tension and shrinking the other. The preferable draw ratio of simultaneous biaxial stretching can be taken in the range of x1.01 times-x 1.5 times in the width direction and the longitudinal direction.

It is preferable that the amount of residual solvent of a web in the case of tenter is 20-100 mass% at the time of tenter start, and it is preferable to dry, putting a tenter until the amount of residual solvent of a web becomes 10 mass% or less, More preferably, it is 5 mass% or less.

30-160 degreeC is preferable, as for the drying temperature in the case of tenter, 50-150 degreeC is more preferable, and 70-140 degreeC is the most preferable.

In a tenter process, it is preferable from a viewpoint of improving the uniformity of a film that there is little temperature distribution of the width direction of an atmosphere, and, as for the temperature distribution of the width direction in a tenter process, within ± 5 degreeC is preferable, and within ± 2 degreeC is more preferable. Preferably, within ± 1 ° C is most preferred.

6) winding process

After the amount of residual solvent in a web becomes 2 mass% or less, it is a process of winding up by a winding machine as a film, and the film with favorable dimensional stability can be obtained by making the amount of residual solvent into 0.4 mass% or less. It is preferable to wind up at 0.00-0.10 mass% especially.

As a winding method, what is generally used may be used, and there exist a static torque method, the positive tension method, the taper tension method, the program tension control method with constant internal stress, etc., and may use them separately.

It is preferable that the film which concerns on this invention is a long film, Specifically, it shows the thing of about 100m-5000m, and is a thing of the form normally provided in roll shape. Moreover, it is preferable that it is 1.3-4 m, and, as for the width of a film, it is more preferable that it is 1.4-2 m.

Although there is no restriction | limiting in particular in the film thickness of the film which concerns on this invention, It is preferable that it is 20-200 micrometers.

<The manufacturing method of retardation film by melt casting film forming method>

The method in the case of manufacturing the resin film base material which concerns on this invention as a retardation film by the melt casting film forming method is demonstrated.

<Melt pellet manufacturing process>

It is preferable to knead | mix and pelletize the composition which comprises the thermoplastic resin film used for melt extrusion normally previously.

The pelletization may be a known method, for example, a dry thermoplastic resin and additives are fed to the extruder as a feeder according to the purpose, kneaded using a single or twin screw extruder, extruded into a strand form from a die, and water cooled or It is possible by air-cooling and cutting.

It is important for the raw materials to be dried before extrusion to prevent the decomposition of the raw materials. In particular, since the cellulose ester is easily hygroscopic, it is preferable to dry at 70 to 140 ° C. for 3 hours or more with a dehumidifying hot air drier or a vacuum drier, and to set the moisture content to 200 ppm or less and 100 ppm or less.

The additives may be supplied to the extruder or may be supplied to individual feeders, respectively. In order to mix uniformly a small amount of additives, such as antioxidant, it is preferable to mix previously.

The mixture of antioxidants may mix solids, and if necessary, antioxidants may be dissolved in a solvent, impregnated with a thermoplastic resin, and mixed, or sprayed and mixed.

A vacuum Nauta mixer or the like is preferable because drying and mixing can be performed at the same time. In addition, when contact with the outlet, such as air from the feeder portion and the die, it is preferable that the atmosphere up and down, such as dehumidified air and the dehumidifying a N ₂ gas.

The extruder is capable of pelletizing so that the shearing force is suppressed and the resin does not deteriorate (molecular weight decrease, coloring, gel formation, etc.), and it is preferable to process it at a low temperature as possible. For example, in the case of a twin screw extruder, it is preferable to rotate in the same direction using a screw of a deep groove type. In view of the uniformity of kneading, the engagement type is preferred.

Film film forming is performed using the pellet obtained by making it above. It is also possible to supply powder of a raw material to an extruder with a feeder as it is, without pelletizing, and to film-form as it is.

<Step of extruding molten mixture from die to cooling roll>

First, the produced pellets are extruded using a single screw or twin screw extruder, and the melting temperature Tm at the time of extruding is set to about 200 to 300 ° C., and filtered through a leaf disk type filter or the like to remove foreign matters, and then from the T die. It is co-extruded in a film form, solidifies on a cooling roll, and is flexible while pressing with an elastic touch roll.

When introduced into the extruder from the feed hopper, it is preferable to prevent the oxidative decomposition or the like under vacuum or under reduced pressure or in an inert gas atmosphere. Tm is also the temperature of the die outlet portion of the extruder.

Stripe-like defects may occur when foreign matter such as scratches or plasticizer condensation adheres to the die. Such a defect is also called a die line, but in order to reduce defects on the surface of the die line or the like, it is preferable to have a structure in which the retention portion of the resin is minimized in the pipe from the extruder to the die. It is preferable to use the thing which does not have a scratch or the like inside the die or the lip as much as possible.

It is preferable that the inner surface which contacts with molten resin, such as an extruder and a die, is given the surface processing which molten resin does not adhere easily, such as making surface roughness small or using a material with low surface energy. Specifically, hard chromium plating or ceramics sprayed are those polished to have a surface roughness of 0.2 S or less.

In the present invention, the cooling roll is not particularly limited, but is a roll having a structure in which a thermally controllable thermal medium or a cooling medium flows through a highly rigid metal roll, and is not limited in size, but sufficient to cool the melt-extruded film. What is necessary is just a magnitude | size, Usually, the diameter of a cooling roll is about 100 mm-1 m.

Examples of the surface material of the cooling roll include carbon steel, stainless steel, aluminum, titanium, and the like. Moreover, in order to improve the hardness of a surface, or to improve peelability with resin, it is preferable to perform surface treatment of hard chrome plating, nickel plating, amorphous chromium plating, etc., ceramic spraying, etc.

The surface roughness of the surface of the cooling roll is Ra, preferably 0.1 µm or less, and further preferably 0.05 µm or less. The smoother the roll surface, the smoother the surface of the resulting film can be. Of course, it is preferable to grind | surface the surface processed further and to make it the surface roughness mentioned above.

In this invention, as an elastic touch roll, Unexamined-Japanese-Patent No. 03-124425, Unexamined-Japanese-Patent No. 08-224772, Unexamined-Japanese-Patent No. 07-100960, Unexamined-Japanese-Patent No. 10-272676, WO97 / 028950, Japan Silicon coated with a thin metal sleeve, as described in Japanese Patent Laid-Open No. Hei 11-235747, Japanese Patent Laid-Open No. 2002-36332, Japanese Patent Laid-Open No. 2005-172940 or Japanese Patent Laid-Open No. 2005-280217. Rubber rolls can be used.

When peeling a film from a cooling roll, it is preferable to control tension and prevent deformation of a film.

<Stretching Step>

In the present invention, the film obtained as described above may be further stretched 1.01 to 3.0 times in at least one direction after passing through the step of contacting the cooling roll.

Preferably, it is preferably stretched 1.1 to 2.0 times in both the longitudinal (film conveyance direction) and the transverse (width direction) directions.

As a method of extending | stretching, a well-known roll stretching machine, a tenter, etc. can be used preferably. In particular, when the retardation film (optical film) also serves as a polarizer protective film, lamination with the polarizing film is possible by making the stretching direction the width direction, which is preferable.

By extending | stretching in the width direction, the slow axis of retardation film (optical film) becomes a width direction.

Usually, a draw ratio is 1.1-3.0 times, Preferably it is 1.2-2 times, and extending | stretching temperature is Tg-Tg + 50 degreeC of resin which comprises a film normally, Preferably it is the temperature of Tg-Tg + 50 degreeC. It is done in a range.

It is preferable to perform extending | stretching under uniform temperature distribution controlled in the longitudinal direction or the width direction. It is preferably within ± 2 degrees, more preferably within ± 1 degree, particularly preferably within ± 0.5 ° C.

When using the film-form resin film produced by the above-mentioned method as retardation film, even if it shrink | contracts a film to a longitudinal direction or the width direction for the purpose of adjusting retardation (retardation) of the said retardation film (optical film) and reducing the rate of dimensional change. do.

In order to shrink | contract in the longitudinal direction, for example, there is a method of shrinking the film by temporarily cutting out the width stretching to relax in the longitudinal direction or by gradually narrowing the interval between adjacent clips of the transverse stretching machine.

Uniformity in the slow axis direction is also important, preferably an angle of -5 to + 5 ° with respect to the film width direction, more preferably in the range of -1 to + 1 °, particularly of -0.5 to + 0.5 °. It is preferable to exist in the range, especially in the range of -0.1 to +0.1 degrees. These variations can be achieved by optimizing the stretching conditions.

It is preferable that it is a long film, The retardation film which concerns on this invention shows a thing of about 100m-10000m specifically, and is a thing of the form normally provided in roll shape. Moreover, it is preferable that it is 1.3-4 m, and, as for the width of a film, it is more preferable that it is 1.4-2.5 m.

There is no restriction | limiting in particular in the film thickness of the retardation film which concerns on this invention, It is preferable to change according to the objective. For example, when using for a polarizer protective film, it is preferable that it is 20-200 micrometers.

(Manufacturing method of liquid crystal display device)

The retardation film which concerns on this invention is used more preferably for the liquid crystal display device manufactured by the roll-to-panel manufacturing method.

In addition, in this application, a "roll-to-panel manufacturing method" does not cut the roll-shaped long polarizing plate in the size of both the length and the width of a liquid crystal cell previously, but is a long roll equivalent to the width of the liquid crystal cell and the width of a liquid crystal cell. It is a manufacturing method which removes a polarizing plate directly from this, bonds it to a liquid crystal cell, and cuts into a liquid crystal cell size with a laser cutter etc. (refer FIG. 3). In this case, the bonding roll is pressed when the polarizing plate is bonded to the liquid crystal cell. Since it is a long polarizing plate, in general, excessive force is easily applied at the time of bonding, and nonuniformity easily occurs in the polarizing plate, but the above conditions according to the present invention are satisfied. When the retardation film to be used is used, nonuniformity hardly occurs, and the variation between lots of optical performance is negligible.

[Example]

Hereinafter, although an Example is given and described about this invention, this invention is not limited to this.

(Film production)

<Production of fine particle dispersion>

11 parts by mass of fine particles (aerosol R972V (Nippon Aerosol Co., Ltd.))

(Average diameter 16nm appearance specific gravity 90g / liter of primary particles)

Ethanol 89 parts by mass

The above was stirred and mixed with a dissolver for 50 minutes, and then dispersed in Manton Gaulin to obtain a fine particle dispersion.

<Particulate addition liquid>

Cellulose acetate (acetyl group substitution degree 2.10, Mn = 140000 was added to the dissolution tank containing methylene chloride, and it melt | dissolved completely by heating, and this was filtered using Azumi filter paper No.244 by Azumiroshi Co., Ltd. make. The fine particle dispersion was slowly added thereto while sufficiently stirring the cellulose acetate solution after filtration, and dispersion was carried out using an attritor so that the particle size of the secondary particles became a predetermined size. Filtration was carried out with FineMet NF to prepare a fine particle addition liquid.

(Composition of the particulate addition liquid)

Methylene chloride 99 parts by mass

4 parts by mass of cellulose acetate (above)

11 parts by mass of fine particle dispersion

The main dope liquid of the following composition was prepared. First, methylene chloride and ethanol were added to the pressure-melting tank. It injected | threw-in stirring the cellulose ester to the pressure dissolution tank containing a solvent. It was melt | dissolved fully, heating and stirring, and it melt | dissolved further adding the plasticizer and a ultraviolet absorber. This was filtered using Azumi filter paper No. 244 by Azumiro-shi Corporation, and the main dope liquid was prepared.

100 mass parts of main dope liquid and 5 mass parts of fine particle addition liquids are added, and it fully mixes with an inline mixer (Toray static tube mixer Hi-Mixer, SWJ), and then it uses a belt casting apparatus, and it is a stainless steel band support body of width 2m Was uniformly flexible. On the stainless steel band support, the solvent was evaporated until the amount of residual solvent became 110%, and it peeled from the stainless steel band support. Then, both ends of the web are stretched in the width direction by a tenter, and after the completion of the stretching, the width direction is maintained for 4 seconds, the tension in the width direction is released, and the width maintenance is released. It conveyed for 30 minutes in 3 drying zones, it dried, and produced protective films 101-122 which have a knurling of width 1cm at the edge part, 118 was 1000m, and the rest 500m each while being 1.49m in width. In addition, the above method is called "prescription A."

The conditions (stretching ratio, heating temperature) of the stretching zone and the amount of residual solvent when entering the tenter are shown in Tables 1 and 2.

<Composition of main doping solution>

Methylene chloride 390 parts by mass

80 parts by mass of ethanol

100 mass parts of cellulose acetate (total substitution degree 2.48, acetyl group substitution degree 1.58, propionyl group substitution degree 0.90, Mn = 160000)

10.0 parts by mass of sucrose benzoate (average degree of substitution 5.5)

Except having used the cellulose acetate (total substitution degree 2.41, acetyl substitution degree 2.41, Mn = 180000) of dope composition, the film 123-149 was produced similarly, 1000 m for 148, and 500 m for the remainder by the said film 123-149. The recipe of is called 'prescription B'.

A film 150 to 185 was produced in 500 m increments in the same manner, except that cellulose acetate having a dope composition of 1.90, an acetyl substitution degree of 1.90, and Mn = 140000 was used, and that the cellulose acetate had an average substitution degree of 5.1. It was. In addition, the manufacturing method of the said film 150-185 is called "prescription C."

<Measurement of Retardation Value of Retardation Film>

After humidifying the produced retardation film at 23 degreeC 55% RH, retardation value was measured by measurement wavelength 590nm using Oji Keisokukiki Co., Ltd. product KOBRA31WPR. For the calculation of Rt, the average refractive index was averaged by measuring the refractive indexes in three directions with an Abbe refractometer, and Rt was calculated using Ro and the phase difference value when the slow axis was inclined 40 ° on the oblique axis.

The measurement results are shown in Tables 3 and 4.

(Production of polarizing plate)

The produced retardation film and KONICA MINOLTA OPTO Co., Ltd. product KC6UA-SW were saponified for 60 second using 50 degreeC 2N KOH aqueous solution, washed with water and dried, and the polarizing plate process was performed as follows.

A 75-micrometer-thick polyvinyl alcohol film was swollen with water at 35 ° C and immersed for 60 seconds in an aqueous solution containing 0.075 g of iodine, 5 g of potassium iodide, and 100 g of water, followed by 3 g of potassium iodide, 7.5 g of boric acid, and water. It was immersed in 45 degreeC aqueous solution containing 100g, and uniaxially stretched (temperature 55 degreeC, draw ratio 5 times). This was washed with water and dried to obtain a polarizer.

Subsequently, the saponification-completed protective films (KC6UA-SW and each retardation film) were formed on both sides of the polarizer using a water pool to sandwich the polarizers with both protective films, and the pressure was 20 to 30 N / cm 2 and the conveyance speed was about 10 m /. It bonded together, and it carried out the drying process of about 2 minutes at 60 degreeC for about 2 minutes at 70 degreeC, and wound up and produced the polarizing plate roll. The adhesion layer was formed in the polyethylene terephthalate film which carried out the peeling process, the surface of the adhesion layer was affixed on the retardation film side of the obtained polarizing plate, and the adhesive polarizing plate roll was produced. Table 3 and Table 4 show the correspondence between the retardation films 101 to 185 and the polarizing plates 201 to 285.

(Fabrication of liquid crystal display device)

The polarizing plate of SONY BRAVIA KDL52W5 was peeled off, the polarizing plate produced above was bonded to the panel by the combination shown in Table 5, Table 6, and Table 7, the liquid crystal display devices 1001-1072 were produced, and the following evaluation was performed. It was done. In the liquid crystal cell of this liquid crystal display device, a color filter and a thin film transistor are arranged on one side of the transparent substrate (see FIG. 1), and the cell of the liquid crystal display device of the present invention is represented by W in Tables 5, 6 and 7 Described. Then, the polarizing plate of BRAVIA KDL52V1 by SONY Corporation was peeled, it bonded to the panel by the combination of Table 5, Table 6, and Table 7, the liquid crystal display devices 3001 to 3004 were produced, and the following evaluation was performed. The liquid crystal cell of this liquid crystal display device is arrange | positioned on the transparent substrate from which a color filter and a thin film transistor differ, and is described as V in Table 7 as a comparative example with respect to the liquid crystal cell of the liquid crystal display device of this invention (refer FIG. 2). It was.

(evaluation)

<Front Contrast>

The white display and the black display were displayed on the screen in the state where the backlight was turned on, and front luminance was measured using Konica Minolta Sensing Co., Ltd. CS2000, and the front contrast was calculated using this. In addition, 10 positions of the calculated value were cut off less than 25, 25 or more and 50 or less were set to 50, and the numerical value rounded up was described in the table | surface.

Front contrast was evaluated according to the following criteria.

◎: more than 3000

○: more than 2500 less than 3000

×: 2500 or less

<Viewing angle>

Using EZ-Contrast160D manufactured by ELDIM, measurement was carried out by displaying white and black similarly to the front contrast measurement, and the minimum angle of contrast 50 was set as the viewing angle in the range of inclination 20 to 70 °. In addition, even when the viewing angle exceeds 80 degrees in all directions, it is expressed as 80 degrees.

Viewing angle was evaluated according to the following criteria.

◎: 70 ° or more

○: more than 60 °, less than 70 °

×: less than 60 °

<Color shift>

The color shift in black display was measured using EZ-Contrast160D manufactured by ELDIM, and it is represented by the coordinate (u1 ', v1') of CIE1976UCS chromaticity diagram, and it is measured coordinate of 360 degrees at 60 degrees of inclination angle from the normal of a liquid crystal display device. The value with which the distance of the front direction (u2 ', v2') and the most coordinate is far was made into color shift. Color shift (ΔCS) = ((u1'-u2 ') ² + (v1'-v2') ² ) ^1/2

Color shift (ΔCS) was evaluated according to the following criteria.

◎: less than 0.040

○: 0.040 or more and 0.060 or less

×: more than 0.060

The said evaluation result is put together in Table 5-9.

As is apparent from the results shown in Tables 5 to 9, it can be seen that the vertically-aligned liquid crystal display device of the present invention is excellent in evaluation of front contrast, viewing angle, and color shift.

(Relationship between Slit Method of Polarizing Plate and Luminance Unevenness)

The polarizing plate 218 was slit into 1151 mm width and the polarizing plate 248 into 647 mm width using the laser slitter, the polarizing plate roll 218A1 of 1151 mm width, and the polarizing plate roll 248B1 of 647 mm width were produced, respectively, and were called polarizing plate roll set 218A1-248B1.

This was set in the manufacturing system of the liquid crystal display device which is a panel bonding apparatus of a rolled polarizing plate, and roll-bonded to 10 liquid crystal cells (liquid crystal display devices 2001-2010). In addition, the polarizing plates 218 and 248 were cut out ten by 52 inch size, and were bonded together to ten liquid crystal cells similarly (liquid crystal display apparatus 2011-2020).

Each was returned to the original backlight configuration to evaluate the luminance nonuniformity.

<Uniformity>

The corresponding liquid crystal display device was moist-heated at 50 ° C. and 90% RH for 24 hours, and the luminance non-uniformity (strong and weak) in the black display after 2 hours of backlight lighting was evaluated visually according to the following criteria. .

◎: luminance unevenness is not seen

○: Weak luminance unevenness is seen, but not annoying in image display

Δ: luminance unevenness is strong, but hardly annoying in image display

X: The luminance nonuniformity is strong, and even an image display is annoying

The evaluation results are shown in Table 10.

As apparent from the results shown in Table 10, the method for producing a vertically oriented liquid crystal display device for manufacturing the vertically oriented liquid crystal display device of the present invention includes at least one of the retardation film A and the retardation film B. It turns out that the manufacturing method of the form which prepares a long roll type polarizing plate and bonds with the said liquid crystal cell by the roll-to-panel manufacturing method is preferable.

1, 9: polarizer
2: retardation film B
3, 7: transparent substrate
4: dielectric constant anisotropy deny liquid crystal
5: color filter
6: thin film transistor
8: retardation film A
10: backlight
11, 13: polarizer
12: liquid crystal cell
20: rolled polarizing plate
21: bonding roll
D: Junction line travel direction

Claims (5)

A vertical alignment liquid crystal cell having a backlight and a liquid crystal having a negative dielectric anisotropy being sandwiched by two transparent substrates, and a vertical polarizer having one polarizing plate on the display surface side and the backlight side of the vertical alignment liquid crystal cell. An alignment type liquid crystal display device, wherein the following requirements (a) to (c) are satisfied.
(a) One of the transparent substrates has a thin film transistor and a color filter.
(b) The said polarizing plate has two retardation films which clamp | pinch a polarizer using polyvinyl alcohol, and the in-plane slow axis of the retardation film of the liquid crystal cell side of the said polarizing film is orthogonal to the absorption axis of the said polarizer.
(c) When the retardation film on the color filter side of one polarizing plate is the retardation film A, and the retardation film on the liquid crystal cell side of the other polarizing plate is retardation film B among the said retardation films, the measurement wavelength is 590 nm at 23 degreeC * 55% RH. The retardation values Rt in the thickness directions of the retardation films A and B measured by are referred to as Rt (A) and Rt (B), respectively, and the value of the ratio of the retardation values Rt in the thickness direction to the in-plane retardation value Ro, respectively. When Rt / Ro (A) and Rt / Ro (B) are respectively represented, the relationship represented by the following formulas 1 to 5 is satisfied.
<Formula 1>
Rt (A) <Rt (B)
<Formula 2>
70 nm <Rt (A) <130 nm
<Formula 3>
130 nm <Rt (B) <200 nm
<Equation 4>
20 nm <Rt (B) -Rt (A) <130 nm
&Lt; EMI ID =
Rt / Ro (A) <Rt / Ro (B)
[Wherein Ro and Rt are defined by the following formula.
<Formula I>
Ro = (n _x -n _y ) × d (nm)
<Formula II>
Rt = {(n _x + n _y ) / 2-n _z } × d (nm)
In the above formula, Ro represents an in-plane retardation value in the retardation film, Rt represents a retardation value in the thickness direction in the film, d represents the thickness of the retardation film, and n _x is the maximum in-plane of the retardation film (ground Axial direction), n _y represents a refractive index in a direction perpendicular to the slow axis in the retardation film plane (narrow direction), n _z represents a refractive index of the retardation film in the thickness direction, and measurement conditions Is the same as above] The relationship represented by the following formulas 6 to 8 is satisfied when the in-plane retardation values Ro of the retardation films A and B are Ro (A) and Ro (B), respectively. Vertically oriented liquid crystal display device.
&Lt; EMI ID =
Ro (A) <Ro (B)
<Equation 7>
40 nm <Ro (A) <90 nm
<Equation 8>
45 nm <Ro (B) <100 nm The vertical alignment liquid crystal display device according to claim 1 or 2, wherein the retardation film A or the retardation film B contains a cellulose ester-based resin. The in-plane retardation value Ro of the said retardation film A and the retardation value Rt of the thickness direction are adjusted by control by a draw ratio at the time of film forming of the retardation film A, The in-plane retardation value Ro of the said retardation film B and the retardation value Rt of the thickness direction are adjusted by control of extending | stretching temperature and film thickness, The vertical orientation liquid crystal display device characterized by the above-mentioned. It is a manufacturing method of the vertically-aligned liquid crystal display device which manufactures the vertically-aligned liquid crystal display device of any one of Claims 1-4, The long which has at least one retardation film of the said retardation film A and the retardation film B. A roll-shaped polarizing plate is prepared and bonded by the roll-to-panel manufacturing method with respect to the said liquid crystal cell, The manufacturing method of the vertically-aligned liquid crystal display device characterized by the above-mentioned.

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