CN101171291A - Cellulose ester film, polarizing plate, and liquid crystal display - Google Patents

Abstract

Disclosed is a cellulose ester film containing a compound represented by the following general formula (1). General formula (1) B-(G-A)<SUB>n</SUB>-G-B In the formula, B represents a benzenemonocarboxylic acid residue; G represents an alkylene glycol residue having 2-12 carbon atoms, an aryl glycol residue having 6-12 carbon atoms, or an oxyalkylene glycol residue having 4-12 carbon atoms; A represents an alkylenedicarboxylic acid residue having 4-12 carbon atoms or an aryldicarboxylic acid residue having 6-12 carbon atoms; and n represents an integer not less than 1.

Description

Cellulose ester film, polaroid and liquid crystal indicator

Technical field

The present invention relates to cellulose ester film, polaroid and liquid crystal indicator, in more detail, relate to cellulose ester film that changes by the reversibility of improving delay (retardation) value that causes because of the humidity change and the light leakage of using this cellulose ester film, angle of visibility characteristic, polaroid and liquid crystal indicator that identification is good.

Prior art

In recent years, along with the exploitation of the notebook computer of slim light-type or slim big frame TV, day by day strengthen for the requirement of the filming of the employed polarizer protection films of display unit such as liquid crystal indicator, maximization, high performance.Wherein just had the narrow problem of angle of visibility of liquid crystal indicator from the past.In order to enlarge the angle of visibility of liquid crystal indicator, the someone proposes to have on the aforementioned protective film method (for example opening flat 6-222213 communique with reference to the spy) as the function of optical compensating sheet.

In addition, desire to reach the disruptive purpose that prevents polaroid, proposed in aforementioned protective film, to import the technology (for example opening the 2001-55402 communique) of linking agent, can improve the yield of polaroid by this with reference to the spy.

And; the variation of explicit (contrast, color, tone) by angle of visibility; being in particular color change becomes problem, the someone propose in the aforementioned protective film to import new bar-shaped compound (for example with reference to the spy open the 2002-267847 communique, the spy opens the 2004-4550 communique).

Also can't improve problems such as demonstration (contrast, color, tone) because of angle of visibility changes, polaroid breaks fully by using above-mentioned means.In addition, existing polaroid uses cellulose ester film as protective film, and this retention depends on that the reversible change of humidity becomes problem.The change of the display quality of the liquid-crystal display that this causes with humidity change is relevant, therefore expects to develop the technique means that addresses this problem.

Further, learn on the large-scale panel more than 17 cun when this optical compensating sheet is used in assembling as the polaroid of protection thin slice, because of the caused light of thermal strain leaks can completely dissolve.Optical compensating sheet not only will have optical compensation liquid crystal born of the same parents' function, and its weather resistance that environment for use is changed also must be good.

Therefore, purpose of the present invention is for providing the cellulose ester film of a kind of improvement caused hysteresis reversibility change because of humidity changes, and uses the light leakage, angle of visibility characteristic of this cellulose ester film, polaroid and the liquid crystal indicator that the property distinguished is good.

Summary of the invention

Above-mentioned problem of the present invention can be reached by following content.

(1) a kind of cellulose ester film is characterized by and contains as the represented compound of following general formula (1);

General formula (1) B-(G-A) n-G-B

In the formula, B represents benzene monocarboxylic acid residue, G represents alkane diol residue or the aryl-diol residue of carbon number 6～12 or the oxyalkylene diol residue of carbon number 4～12 of carbon number 2～12, A represents the alkylene dicarboxylic acids residue of carbon number 4～12 or aryl dicarboxylic acid's residue of carbon number 6～12, in addition, n represents the integer more than 1.

(2) as described above the cellulose ester film of (1), wherein the molecular weight of the compound of this general formula (1) is 300～2000.

(3) as described above the cellulose ester film of (1) or (2) wherein further contains the polyol ester based compound.

(4) as described above each cellulose ester film in (1)～(3), wherein this cellulose ester film is for containing the cellulose ester that satisfies following formula (I), (II) simultaneously;

(I)2.1≤X+Y≤2.9

(II)1.0≤X≤2.9

But X represents the substitution value of ethanoyl, and Y represents the substitution value of lipid acid ester group.

(5) as described above each cellulose ester film in (1)～(4), wherein the width of this cellulose ester film is 1.4～4m.

(6) as described above each cellulose ester film in (1)～(5), the represented Ro of wherein following formula is below the above 300nm of 20nm under 23 ℃, 55%RH condition, the represented Rt of following formula is below the above 400nm of 70nm under 23 ℃, 55%RH condition;

Ro＝(nx-ny)×d

Rt＝((nx+ny)/2-nz)×d

In the formula, nx, ny, nz respectively represent main shaft x, the y of indicatrix, the specific refractory power of z direction, and nx, ny represent the specific refractory power of direction in this cellulose ester film face, and nz represents the specific refractory power of this cellulose ester film thickness direction.In addition, nx 〉=ny, d represent this cellulose ester film thickness (nm).

(7) a kind of polaroid is characterized by the cellulose ester film that is provided with as described above in (1)～(6) each at least 1 of polarizer.

(8) as described above the polaroid of (7), wherein this cellulose ester film is as the polaroid protective film, is located at least 1 of this polarizer.

(9) as described above the polaroid of (7), wherein this cellulose ester film is as phase-contrast film, is located at least 1 of this polarizer.

(10) as described above each polaroid in (7)～(9), wherein in this cellulose ester film, the represented Ro of following formula is below the above 300nm of 20nm under 23 ℃, 55%RH condition, and the represented Rt of following formula is below the above 400nm of 70nm under 23 ℃, 55%RH condition;

Ro＝(nx-ny)×d

Rt＝((nx+ny)/2-nz)×d

In the formula, nx, ny, nz respectively represent main shaft x, the y of indicatrix, the specific refractory power of z direction, and nx, ny represent the specific refractory power of direction in this cellulose ester film face, and nz represents the specific refractory power of this cellulose ester film thickness direction; In addition, nx 〉=ny, d represent this cellulose ester film thickness (nm).

(11) a kind of liquid crystal indicator is characterized by use each polaroid in (7)～(10) as described above.

The simple declaration of accompanying drawing

Fig. 1 represents to illustrate the figure that extends angle of strike degree under the step.

Fig. 2 represents the sketch chart of an example of tentering step used in the present invention.

Embodiment

Below elaborate to implementing most preferably form of the present invention, but the present invention is not defined in this.

Below describe the present invention in detail.

Cellulose ester film of the present invention is characterized by and contains the aromatic series terminal ester based compound represented as following general formula (1) (the aromatic series terminal ester based compound shown in the following general formula (1) is only represented with aromatic series terminal ester based compound).

General formula (1) B-(G-A) n-G-B

(in the formula, B represents benzene monocarboxylic acid residue, G represents alkane diol residue or the aryl-diol residue of carbon number 6～12 or the oxyalkylene diol residue of carbon number 4～12 of carbon number 2～12, A represents the alkylene dicarboxylic acids residue of carbon number 4～12 or aryl dicarboxylic acid's residue of carbon number 6～12, in addition, n represents the integer more than 1).

In the general formula (1), constituted by alkylene dicarboxylic acids residue or the aryl dicarboxylic acid's residue shown in the alkane diol residue shown in benzene monocarboxylic acid residue shown in the B and the G or oxyalkylene diol residue or fragrant diol residue, the A, and obtained under the same reaction of general polyester based compound.

Benzene monocarboxylic acid composition as aromatic series terminal ester based compound of the present invention, for example phenylformic acid, p-tert-butyl benzoic acid, adjacent toluic acid, a toluic acid, to toluic acid, mesitylenic acid, ethyl benzoate, n-propylbenzene formic acid, benzaminic acid, acetoxy-benzoic acid etc., can use these a kind or mix mixture more than 2 kinds.

As carbon number 2～12 alkane diol components of aromatic series terminal ester based compound of the present invention, can enumerate ethylene glycol, 1, the 2-propylene glycol, 1, ammediol, 1, the 2-butyleneglycol, 1,3 butylene glycol, the 2-methyl isophthalic acid, ammediol, 1, the 4-butyleneglycol, 1, the 5-pentanediol, 2,2-dimethyl-1, ammediol (neopentyl glycol), 2,2-diethyl-1, ammediol (3,3-dihydroxymethyl pentane), 2-normal-butyl-2-ethyl-1, ammediol (3,3-dihydroxymethyl heptane), the 3-methyl isophthalic acid, 5-pentanediol-1, the 6-hexylene glycol, 2,2,4-trimethylammonium-1,3-pentanediol, 2-ethyl-1, the 3-hexylene glycol, the 2-methyl isophthalic acid, the 8-ethohexadiol, 1, the 9-nonanediol, decamethylene-glycol, 1,12-octadecandiols etc., these glycol can use a kind or mix mixture more than 2 kinds.

In addition, oxyalkylene diol component as the carbon number 4～12 of aromatic series terminal ester based compound of the present invention, for example enumerate Diethylene Glycol, triethylene glycol, TEG, dipropylene glycol, tripropylene glycol etc., these glycol can use the mixture more than a kind or 2 kinds.

In addition, as the fragrant diol component of the carbon number 6～12 of aromatic series terminal ester based compound of the present invention, for example can enumerate quinhydrones, Resorcinol, dihydroxyphenyl propane, Bisphenol F, bis-phenol etc., these glycol can use mixture more than a kind or 2 kinds.

Alkylene dicarboxylic acids composition as the carbon number 4～12 of aromatic series terminal ester based compound of the present invention, for example can enumerate succsinic acid, toxilic acid, fumaric acid, pentanedioic acid, hexanodioic acid, nonane diacid, sebacic acid, 12 carbon dicarboxylic acid etc., can use the mixture that mixes more than a kind or 2 kinds these.As aryl dicarboxylic acid's composition of carbon number 6～12, can enumerate phthalic acid, m-phthalic acid, terephthalic acid, 1,5-naphthalene dicarboxylic acids, 1,4-naphthalene dicarboxylic acids etc.

Several molecular-weight average of aromatic series terminal ester based compound used in the present invention serve as preferred with 300～2000, more preferably 500～1500 scope.In addition, preferably this acid number is below the 0.5mgKOH/g, and hydroxyl value is below the 25mgKOH/g, and more preferably acid number is below the 0.3mgKOH/g, and more preferably hydroxyl value is below the 15mgkOH/g.The molecular weight of aromatic series terminal ester based compound of the present invention is measured by gel permeation chromatography (GPC).For the low-molecular weight compound that can't measure by GPC, by value that structural formula calculated as molecular weight.

(acid number, the hydroxyl value of aromatic series terminal ester based compound)

As acid number, be the mg number that neutralization is contained in the required potassium hydroxide of acid (carboxyl that is present in molecular end) among the test portion 1g.Acid number and hydrogen-oxygen valency are the mensuration that is as the criterion according to JISK 0070.

Below enumerate the synthetic example of relevant aromatic series terminal ester based compound of the present invention.

＜sample 1 (aromatic series terminal ester based compound sample) 〉

The phthalic acid 820 parts (5 moles), 1 of once packing in the reaction vessel, 2-propylene glycol 608 parts (8 moles), phenylformic acid 610 parts (5 moles) and as 0.30 part of the tetra isopropyl titanate of catalyzer, under nitrogen gas stream, stir, with 1 yuan of superfluous alcohols of reflux exchanger backflow, and continue at 130～250 ℃ and be heated to that to become acid number be below 2, continuously the water that generates is removed.Next is 200～230 ℃ following 6.65 * 10 ³Pa～finally be 4 * 10 ²Remove under the decompression below the Pa and distillate composition, this after-filtration obtains having the aromatic series terminal ester based compound of following proterties.The aromatic series terminal ester based compound of gained has the structure of the following compound that exemplifies (1).

Viscosity (25 ℃, mPas); 19815

Acid number; 0.4

＜sample 2 (aromatic series terminal ester based compound sample) 〉

Once pack in the reaction vessel hexanodioic acid 500 parts (3.5 moles), phenylformic acid 305 parts (2.5 moles), Diethylene Glycol 583 parts (5.5 moles) and as 0.45 part of the tetra isopropyl titanate of catalyzer, identical with the sample No.1 in addition aromatic series terminal ester based compound that obtains having following proterties down.The aromatic series terminal ester based compound of gained has the structure of the following compound that exemplifies (2).

Viscosity (25 ℃, mPas); 90

Acid number; 0.05

＜sample 3 (aromatic series terminal ester based compound sample) 〉

Once pack in the reaction vessel m-phthalic acid 570 parts (3.5 moles), phenylformic acid 305 parts (2.5 moles), dipropylene glycol 737 parts (5.5 moles) and as 0.40 part of the tetra isopropyl titanate of catalyzer, identical with the sample No.1 in addition aromatic series terminal ester based compound that obtains having following proterties down.The aromatic series terminal ester based compound of gained has the structure of the following compound that exemplifies (3).

Viscosity (25 ℃, mPas); 33400

Acid number; 0.2

Below enumerate the particular compound of aromatic series terminal ester based compound, but the present invention is not limited to this.

[changing 1]

[changing 2]

The amount of relevant aromatic series terminal ester based compound of the present invention preferably contains 1～20 quality % in the cellulose ester film, the spy is preferably 3～11 quality %.

Among the present invention, preferably further contain the polyol ester based compound.

Polyol ester based compound used in the present invention is preferably the compound that ester became of aliphatic polyol and monocarboxylic acid more than 2 yuan, and intramolecularly has aromatic nucleus or cycloalkyl ring.

The polyvalent alcohol that is used in aforementioned polyol ester based compound is shown in the following general formula (2).

General formula (2) R1-(OH) _n

In the formula, R1 represents n valency organic radical.N represents the positive integer more than 2, OH basis representation alcohol or phenol hydroxyl.

As the preferred polyhydric alcohols example, for example can enumerate following example, but the present invention is not defined in this.Ribitol, arabitol, ethylene glycol, Diethylene Glycol, triethylene glycol, TEG, 1,2-propylene glycol, 1, ammediol, dipropylene glycol, tripropylene glycol, 1,2-butyleneglycol, 1,3-butyleneglycol, 1,4-butyleneglycol, dibutylene glycol, 1,2,4-trihydroxybutane, 1,5-pentanediol, 1,6-hexylene glycol, hexanetriol, melampyrum, mannitol, 3-methylpentane-1,3,5-triol, tetramethyl ethylene ketone, Sorbitol Powder, TriMethylolPropane(TMP), trimethylolethane, Xylitol etc.Be preferably triethylene glycol, TEG, dipropylene glycol, tripropylene glycol, Sorbitol Powder, TriMethylolPropane(TMP), Xylitol especially.

Monocarboxylic acid as being used in aforementioned polyol ester is not particularly limited, and can use known aliphatic monocarboxylic acid, alicyclic monocarboxylic acid, aromatic monocarboxylate etc.Can improve water vapour permeability, retention when using alicyclic monocarboxylic acid, aromatic monocarboxylate so more preferably.As monocarboxylic acid example more preferably, can enumerate following person, but the present invention is not defined in this.

As aliphatic monocarboxylic acid, can preferably use the straight chain with carbon number 1～32 or the lipid acid of side chain.Carbon number 1～20 is for more preferably, and carbon number 1～10 is special preferred.Can increase with the intermiscibility of cellulose ester when using acetate and die more preferably, also acetate can be mixed use with other monocarboxylic acid.

As preferred aliphatic monocarboxylic acid, for example can enumerate saturated fatty acids such as acetate, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, sad, n-nonanoic acid, capric acid, 2-ethyl-caproic acid, undecanoic acid, dodecylic acid, tridecanoic acid, tetradecanoic acid, pentadecylic acid, palmitinic acid, margaric acid, stearic acid, nondecylic acid, arachic acid, docosoic, carnaubic acid, cerinic acid, carboceric acid, octocosoic acid, triacontanoic acid, n-Dotriacontanoic acid; Unsaturated fatty acidss such as undecylenic acid, oleic acid, Sorbic Acid, linolic acid, linolenic acid, arachidonic acid etc.As the example of preferred alicyclic monocarboxylic acid, can enumerate ring penta carboxylic acid, cyclohexane carboxylic, the hot carboxylic acid of ring or these derivatives.As preferred aromatic monocarboxylate's example, can enumerate on benzoic phenyl ring such as phenylformic acid, toluic acid aromatic monocarboxylate or these derivatives that the monocarboxylic acid that imports alkyl, biphenyl carboxylic acids, naphthalene monocarboxylic acid, tetralin carboxylic acid etc. have the phenyl ring more than 2.Be in particular phenylformic acid for preferred.

The molecular weight of polyol ester based compound is not particularly limited, and serves as preferred with the scope of molecular weight 300～1500, and 350～750 scope is for more preferably.More difficult volatilization of molecular weight, thus preferred, by water vapour permeability, and the intermiscibility smaller of cellulose ester be preferred.The carboxylic acid that is used in polyol ester can be and is mixed into more than a kind or 2 kinds preferably.In addition, the OH base in the polyvalent alcohol can be esterification or a part of situation that keeps the OH base entirely.It below is the example of the particular compound of polyol ester.

The amount of aforementioned polyvalent alcohol based compound is preferably and contains 0～15 quality % in the cellulose ester film, and the spy is preferably 3～10 quality %.

[changing 3]

[changing 4]

[changing 5]

[changing 6]

Cellulose ester film of the present invention except that above-mentioned aromatic series terminal ester based compound or polyol ester based compound, further also preferably contains softening agent.

Beyond above-mentioned aromatic series terminal ester based compound or the polyol ester based compound, can the stripping of aforesaid compound or softening agent be reduced by containing softening agent, though its reason understands, can be thought of as because of minimizing and be equivalent to the addition of a kind and the interaction by aforesaid compound and softening agent and aforesaid compound, softening agent and cellulose ester can suppress stripping.

Softening agent used in the present invention is the following person of being given an example, but there is no specific limited in this.

It is to use diethyl phthalate, dimethoxy-ethyl phthalic acid ester, dimethyl benzene dicarboxylic acid esters, dioctyl phthalic acid ester, dibutyl phthalic acid ester, di-2-ethylhexyl phthalate etc. in the softening agent that the softening agent of phosphoric acid ester system can use triphenyl, tricresyl alkaliine, cresols diphenyl phosphoester, octyl group diphenyl phosphoester, phenylbenzene biphenyl phosphoric acid ester, trioctylphosphine phosphoric acid ester, Tributyl phosphate ester etc., phthalic acid ester.

These softening agent can separately or mix use more than 2 kinds.The amount of above-mentioned aromatic series terminal ester based compound or polyol ester based compound and softening agent with their total amount, is preferably 4～20 quality % to cellulose ester, more preferably 6～16 quality %, special preferred 7～11 quality %.If the addition of these additives is too much the time, and film can be crossed softness and can increase the reduced rate of spring rate when heating, if when addition is very few, the water vapour permeability of film can descend.

Be used in cellulose ester of the present invention, the low-grade fatty acid ester of preferred cellulose.Lower fatty acid represents that carbonatoms is the lipid acid below 6 in the cellulosic low-grade fatty acid ester, for example can use cellulose ethanoate, cellulose propionate, cellulose butylate etc. or special open flat 10-45804 number, spy and open mixed aliphatic esters such as cellulose ethanoate propionic ester that No. the 2319052nd, flat 108-231761, United States Patent (USP) etc. are put down in writing, cellulose acetate butyrate.In the above-mentioned record, the special cellulosic low-grade fatty acid ester that preferably uses is cellulosic triacetate, cellulose ethanoate propionic ester.These cellulose ester can be used alone or as a mixture.

The situation of cellulosic triacetate is preferably 54.0～62.5% for using average degree of acetylation (in conjunction with the acetate amount), and more preferably average acetate turns to 58.0～62.5% cellulosic triacetate.

Preferred cellulose ester beyond the cellulosic triacetate is, has carbonatoms and be the substituting group of 2～4 acyl group, and the substitution value of ethanoyl is X, when the substitution value of propenyl is Y, satisfies following formula (I) and cellulose ester (II) simultaneously.

(I)2.1≤X+Y≤2.9

(II)1.0≤X≤2.9

(but X represents the substitution value of ethanoyl, Y represents the substitution value of lipid acid ester group)

More preferably satisfy the cellulose ester of following formula (I) ' and (I I) ' simultaneously.

(I)′2.4≤X+Y≤2.9

(II)′1.0≤X≤2.9

Wherein, the cellulose ethanoate propionic ester of 1.0≤X≤2.0,0.5≤Y≤1.3 is preferred.The part by acyl substituted does not generally exist as the form of hydroxyl.Can be synthetic by these known methods.These acyl substituted degree can be measured according to the method for ASTM-D817-96 defined.

Cellulose ester system is by the cellulose ester as the synthetic gained of raw material such as cotton waste, wood pulp, gombo hemp, but each the independent or mixing use of the cellulose ester of these gained.The cellulose ester that is in particular the synthetic gained of cotton waste (the following suede that abbreviates as sometimes), wood pulp is to be used alone or as a mixture to preferably.

Cellulose ester used in the present invention be the value of weight average molecular weight (Mw)/number molecular-weight average (Mn) be 1.4～3.0 cellulose ester for preferred, 1.4～2.5 scope more preferably.Mw/Mn is in this scope the time, and the phase differential performance property of extending cellulose ester film can improve, and the gonorrhoea during extension etc. can improve.

Cellulosic molecular-weight average and molecular weight distribution can use high performance liquid chromatography to determine with known method.Use this to calculate several molecular-weight average, weight average molecular weight, calculate this than (Mw/Mn).

The molecular weight of cellulose ester is, number molecular-weight average (Mn) are 30000～200000 for preferred, and 40000～170000 for more preferably.The molecular weight of cellulose ester is big more, and the velocity of variation of the hysteresis by humidity then diminishes, but molecular weight is when excessive, and the viscosity of the lysate of cellulose ester can be too high, and productivity is reduced.

Use the condition determination of several molecular-weight average, weight average molecular weight of high performance liquid chromatography as follows.

Solvent: methylene dichloride

Tubing string: Shodex K806, K805, K803G (3 of clear and electrician's (strain) system are connected use)

Tubing string temperature: 25 ℃

Test portion temperature: 0.1 quality %

Detector: RI Model 504 (making of GL scientific company)

Mercury: L6000 (Hitachi (strain) made)

Flow: 1.0ml/min

Check and correction curve: the check and correction curve that uses 13 sample gained of polystyrene standard STK polystyrene standard (eastern Cao (strain) making) Mw=1000000～500.13 samples preferably use down with almost equal interval.

Secondly, the manufacture method of cellulose ester film of the present invention is done explanation.Being fabricated to of cellulose ester film of the present invention, with cellulose ester and additive be dissolved in the step that modulates rubber cement in the solvent, with the step of rubber cement curtain coating on support, with the rubber cement exsiccant step of curtain coating.

For the cellulose ester concentration in the rubber cement, curtain coating can lower drying load when denseer behind support, thus preferred, but cellulose ester concentration worsens filtering accuracy if can increase burden when filtering when too high.Be preferably 10～50 quality % as the concentration that can take into account, more preferably 15～35 quality %.

The employed solvent of rubber cement can use separately, also can and usefulness, be seen as preferably by production efficiency when using the mixed solvent of the good solvent of cellulose ester and poor solvent, good solvent is seen as preferably by the solvability of cellulose ester more for a long time.The preferable range of the mixture ratio of good solvent and poor solvent is that good solvent is 70～98 quality %, and poor solvent is 30～2 quality %.

So-called good solvent with poor solvent is, dissolving cellulos ester person be a good solvent separately, and independent descend can swelling or can dissolving person's poor solvent.Therefore; average degree of acetylation by cellulose ester can change good solvent, poor solvent; when for example acetone being used as solvent; in the acetic ester of cellulose ester (in conjunction with acetic acid amount 55%), the cellulose ethanoate propionic ester is good solvent, is poor solvent in the cellulosic acetic ester (in conjunction with acetic acid amount 60%).

Good solvent is not particularly limited, and for example can use organic halogen compound or dioxolane classes such as methylene dichloride when cellulose ester film, can use methylene dichloride, acetone, methyl acetate etc. when the cellulose ethanoate propionic ester.

In addition, poor solvent used in the present invention and indefinite for example can use methyl alcohol, ethanol, propyl carbinol, hexanaphthene, acetone, pimelinketone etc. for preferred.

The dissolving method of cellulose ester during as the rubber cement liquid of the above-mentioned record of modulation can use general method.But be heated to more than the boiling point under the normal pressure when combined heated and pressurization.More than the boiling point under the normal pressure of solvent, and add and depress that solvent heats under can the ebullient range temperature and during stirring and dissolving, the bulk that can prevent gel or caking not the generation of solute so more preferably.In addition, with cellulose ester mix with poor solvent make its moistening or swelling after, add good solvent dissolved method again and also preferably use.

Pressurization can be used method that rare gas element such as nitrogen is pressed into or be undertaken by the method that heating is risen the vapour pressure of solvent.Heating can preferably be undertaken by the outside, and for example the temperature of can carrying out easily of external-cover-type is controlled, so preferred.

Add the Heating temperature of solvent, the deliquescent viewpoint by cellulose ester when higher is seen as preferably, but Heating temperature when too high required pressure understand excessive and make the productivity variation.Preferred Heating temperature is 45～120 ℃, more preferably 60～110 ℃, and further preferred 70～105 ℃.In addition, pressure is can the ebullient degree to be adjusted to solvent under the design temperature.

Secondly, this cellulose ester solution is preferably filtered with suitable filter materials such as filter paper.As filtering material, desire to remove insolubles etc. and use absolute filtering accuracy smaller, but if absolute filtering accuracy too hour has the problem that the obstruction of filtering material is easier to take place for preferred.Therefore, absolute filtering accuracy be the following filter material of 0.008mm for preferred, the filter material of 0.001～0.008mm scope is for more preferably, the filter material of 0.003～0.006mm scope be preferably further.

Filtering filter material is not particularly limited, and can use general filter material, can enumerate metal filter materials such as the filter material of polypropylene, special teflon polymer systems such as (registered trademarks) or stainless steel, and these are not because of there being coming off of fiber etc., so preferred.

The filtration of rubber cement can be used general method, and under normal pressure more than the boiling point of solvent and add and depress solvent not under the ebullient temperature range, while heat filtering method, the filter pressure reduction before and after filtering (below, be called filter and press) rises less for preferred.Preferred temperature is 45～120 ℃, and 45～70 ℃ for more preferably, and 45～55 ℃ be preferably further.Preferred filter is pressed less.Filter is pressed serve as preferred below the 1.6MPa, and the following person of 1.2MPa is for more preferably, and the following person of 1.0MPa is preferably further.

Support in curtain coating (casting) step preferably uses the surface through the stainless steel of mirror process conduction band or with cylinder for no reason.The support temperature of casting step be 0 ℃～do not reach under the temperature of solvent boiling point, so temperature is high more to accelerate more preferably rate of drying, but can foam when too high, or has the situation that planarity worsens.More preferably the support temperature is 0～40 ℃, and curtain coating is for more preferably on 5～30 ℃ the support.Though the method for temperature of control support is not particularly limited, can use the method for blowing warm air or cold wind or the method that the warm water pad is contacted with support.Because thermal conduction can be carried out more efficiently when using the warm water pad, the temperature that can shorten support arrives the time of certain temperature, so preferred.Sometimes the wind that needs to use the temperature higher when using warm wind than purpose temperature.

Desire the excellent planar of display fibers cellulose ester film, the residual solvent amount when being peeled off by support serve as preferably with 10～120%, more preferably 20～40% or 60～120%, and the spy is preferably 20～30% or 70～115%.The residual solvent amount as shown in the formula define.

Residual solvent amount=((quality after the quality-heat treated before the heat treated)/(quality after the heat treated)) * 100 (%)

And the heat treated when measuring the residual solvent amount is, with film in 115 ℃ of following heat treated 1 hour.

In addition, in the drying step of cellulose ester film, making the residual solvent amount after the further drying of being peeled off by support of film is for preferred, more preferably below 0.5% below 3%.Use cylinder to dangle under mode or the tentering mode as the film drying step 1 while transporting film exsiccant mode.

Residual solvent amount after being peeled off by support is carried out fabric width in the tentering mode and is kept or extend for a long time, can improve thin film planar and preferred.The suction spring rate of cross direction can become big when in addition, the extension ratio of tentering was excessive.More preferably extension ratio is 0～40%, 1～35% for more preferably.When extension ratio 0% kept for fabric width, the residual solvent amount can obtain for a long time and extend identical effect.

The method of dry film is not particularly limited, and can generally carry out with hot blast, infrared rays, heating drum, microwave etc., is carried out to preferably with hot blast by easy.

So drying temperature is to rise to preferably with stage under 40～150 ℃, can improve dimensional stability when carrying out further preferred under 50～140 ℃ scope.In addition, so the suction spring rate improved preferred when dry in 10～40 minutes under ℃ scope of the softening temperature of film ± 20.Control in the drying of softening temperature ± 20 by film ℃ and transport under the tension force suction spring rate of may command curtain coating direction.Preferably transporting tension range is 80～350N/m, and 150～300N/m is for more preferably.

Film thickness is not particularly limited, and for example can make the film of arbitrary thickness of 10 μ m～1mm degree.The thickness that is preferably after drying, extension etc. are handled serves as preferred with 10～500 μ m, and the spy is preferably 30～120 μ m.

Cellulose ester film of the present invention is that 1～4m person serves as preferred with width.

The cellulose ester film of the wide width of cloth can obtain planarity fiber with excellent cellulose ester film by formation of the present invention, so can obtain unusual effect.Be in particular 1.4～4m person for preferred, the spy is preferably 1.4～2m.Be difficult to carrying when surpassing 4m.

Cellulose ester film of the present invention can be in response to additives such as required interpolation UV light absorber, dyestuff, matting agents.By the viewpoint of the liquid crystal deterioration preventing of UV light absorber, the following ultraviolet radiation absorption of wavelength 370nm can be good, and by the viewpoint of good liquid crystal expressivity, the less person of absorption of the visible light that wavelength 400nm is above is preferred.Among the present invention, being in particular under the wavelength 370nm transmitance and being 10% following person for preferred, more preferably is below 5%, more preferably below 2%.

Among the present invention, intramolecularly has the UV light absorber of the aromatic ring more than 2 for special preferred.Employed UV light absorber is not particularly limited, and for example can enumerate dihydroxy benaophenonel based compound, benzotriazole based compound, salicylate based compound, benzophenone based compound, cyanoacrylate based compound, nickel complexing salt based compound, inorganic powder etc.Preferably UV light absorber benzotriazole high for the transparency, that have the excellent results that prevents that polaroid or Liquid crystal module from worsening is that UV light absorber or benzophenone series UV light absorber are preferred, and the painted benzotriazole of not wanting still less is that UV light absorber is special preferred.TINUVIN 109, TINUVIN 171, TINUVIN 326, TINUVIN 327, the TINUVIN328 etc. that can enumerate チ バ ス ペ シ ヤ Le テ イ ケ ミ カ Le ズ making as the object lesson of UV light absorber are preferred.But only be not defined in this.

The mixture that UV light absorber can be used separately or mix more than 2 kinds uses.In addition, it is preferred also can using polymeric UV absorber as UV light absorber, and the UV light absorber of opening the polymer-type of flat 6-148430 number record with the spy serves as preferred especially.

The addition means of UV light absorber can be dissolved in UV light absorber and makes an addition to rubber cement behind the organic solvents such as alcohols or methylene dichloride, two oxa-s, penta ring or directly add in composition of colloidal slurry.As the person that can not be dissolved in the organic solvent of inorganic powder, add again after in organic solvent and cellulose ester, using dissolver or skin grinder to disperse.

The usage quantity of UV light absorber is different according to the kind of UV light absorber, working conditions etc., but when the dry film thickness of cellulose ester film is 30～200 μ m, be 0.5～4.0 quality % for cellulose ester film for preferred, 0.6～2.0 quality % is for more preferably.Among the present invention, can add blue dyes during the Huang partially of desire inhibition film.Can enumerate the anthraquinone based dye as dyestuff more preferably.The anthraquinone based dye is that arbitrary position can have any substituting group among the 1st to the 8th of anthraquinone.As substituting group more preferably is anilino, hydroxyl, amino, nitro or hydrogen atom.These additions that dye to film are 0.1～1000 μ g/m under the purpose of the transparency of keeping film ², more preferably be 10～100 μ g/m ²

The present invention can add the particulates such as silicon oxide as matting agent when needing.The matting agent particulate can carry out surface treatment by organism, because of the mist value that can reduce film is died more preferably.As surface treatment more preferably organism can enumerate halogen silicane, alkoxyl silicone alkanes, silazane, siloxanes etc.

The extinction effect of median size the greater of particulate is bigger, and the transparency is better during median size smaller, so the median size of the primary particle of particulate is 5～50nm for preferred, more preferably 7～20nm.

Though the particulate as silicon oxide is not particularly limited, for example can enumerate AEROSIL200,200V, 300 that Japanese Aerosil limited-liability company makes, R972, R972V, R972CF, R974, R202, R805, R812, OX50, TT600 etc., be preferably AEROSIL200,200V, R972, R972V, R974, R202, R805, R812 etc.

But various additive portion-wise addition are in rubber cement liquid, or prepare the additive lysate in addition and carry out online interpolation.During online interpolation additive lysate, desire to make the Combination of itself and rubber cement good, the plain ester of solubilized small amount of fibers is preferred.The amount of preferred cellulose ester is 1～10 mass parts for the solvent of 100 mass parts, more preferably is 3～5 mass parts.

Carry out online interpolation among the present invention, when mixing, for example can use mixing machine (eastern レ engineering corporation make), the SWJ on-line mixing machines such as (mixing tank Hi-Mixer in the eastern レ silent oscillation pipe) etc. of leaving standstill.

(phase-contrast film)

Liquid-crystal display when using liquid crystal material with anisotropy or polaroid, has when being seen by the front and can well be shown, but the problem of the angle of visibility that display performance can reduce when being seen by the inclined-plane.So desire improves performance must the view angle compensation plate.Mean refractive index is distributed as in the structure cell thickness direction to bigger, but direction is less in face.For this reason, as this compensating plate, for having the interior little specific refractory power of direction of specific refractory power specific surface of film thickness direction to eliminating this anisotropy person, it is effectively that what is called has a negative property structure, and cellulose ester film of the present invention also can be used as the phase-contrast film with function like this and uses.

Among the present invention, the aforementioned fibers cellulose ester film is through extending, and the defined Ro of following formula be 20nm～300nm under 23 ℃, 55%RH condition, is preferably during as phase-contrast film when Rt be 70nm～400nm under 23 ℃, 55%RH condition.

Ro＝(nx-ny)×d

Rt＝((nx+ny)/2-nz)×d

(in the formula, nx, ny, nz respectively represent main shaft x, the y of indicatrix, the specific refractory power of z direction, and nx, ny represent the specific refractory power of direction in this cellulose ester film face, and nz represents the specific refractory power of this cellulose ester film thickness direction; In addition, nx 〉=ny, d represent this cellulose ester film thickness (nm)).

And hysteresis Ro, Rt use automatic birefringence meter to measure.For example use KOBRA-21ADH (prince's instrumentation machine (strain) system), in 23 ℃, under the environment of 55%RH, carrying out wavelength is the sluggishness mensuration of the film of 590nm.

And Ro satisfies following formula for preferred with the ratio of Rt.

2≤Rt/Ro≤5

One example of the extension step (also being called the tentering step) when making cellulose ester film of the present invention uses Fig. 2 explanation.

Support in the steps A of Fig. 2 to transport the step of step D0 to film through transporting by not shown film, among the step B of next, prolong past cross direction (with the vertical direction of the film direction of travel) prolongation of film under the angle as shown, in step C, after extending end, in the step of supporting to transport under the film.

Preferably from film peel off begin preceding to step B and/or step C after, setting can be cut away the cutting machine of film cross direction end.Be preferably especially the A step begin before setting can cut away the cutting machine of film end.When cross direction carried out same extension, excision film end situation was made comparisons with the condition of not excising the film end before being in particular step B and beginning, and the former can obtain orientation angle and distribute through the effect of improvement.

This thinks to suppress from more the peeling off to the effect of the meaningless extension of the length direction between wide extension step B of residual solvent amount.

In the tentering step, desire is improved orientation angle and is distributed, and preferably differing temps can be divided.In addition, desire to make respectively to divide between the differing temps division can not cause interference, it is also preferred that neutral region can be set.

And, extend operation and may be partitioned into multistage enforcement, implement two in curtain coating direction, cross direction and extend to preferred.Also can carry out two extension or stage enforcement when in addition, carrying out two extensions simultaneously.What is called is stage at this moment can be docile and obedient preface and carry out the different extension of bearing of trend for for example, also unidirectional extension can be divided into the multistage, and the extension of different direction adds in arbitrary stage.That is, for example can carry out the following extension stage.

Extend-extend-extend-extend in the curtain coating direction in the curtain coating direction in the curtain coating direction in cross direction

In cross direction extend-in cross direction extend-the curtain coating direction extend-extends in the curtain coating direction

In addition, carry out 2 extensions simultaneously and also comprise that a side extends, the opposing party then relaxes the situation of shrinking under the tension force.The more preferably extension ratio that carries out 2 extensions simultaneously is * 1.05～* 1.5 times in cross direction, is * 0.8～* 1.3 times in length direction (curtain coating direction), and being in particular cross direction is * 1.1～* 1.5 times, and it is preferred that length direction is * 0.8～* 0.99 times.It is * 1.1～* 1.4 times that the spy is preferably cross direction, and length direction is * 0.9～* 0.99 times.

In addition, so-called " bearing of trend " of the present invention, normally used situation are meant to extend and directly add the direction of extending stress when operating, but situation about using sometimes means when the multistage is carried out two extensions, final extension ratio becomes a big side (that is, generally becoming the direction of slow phase axle).Mainly use the latter's meaning when only representing when being in particular the record of relevant size changing rate with " bearing of trend ".The residual solvent amount is as described above shown in the formula.

Carry out extension when operation of cellulose ester film, desire to reach in 80 ℃, the improvement of dimensional stability under the 90%RH condition preferably in the presence of residual solvent, and is extended operation under the heating condition.

When the past cross direction of known film extended, the cross direction of film can make the optics distribution of phase axle late (following is the orientation angle distribution) worsen.Rth and Ro value are certain ratio, and orientation angle is distributed in and carries out cross direction under the good order and condition when extending, and exist the more preferably relativeness of film temperature among steps A, B, the C.The film temperature of steps A, B, C terminal point respectively is Ta ℃, Tb ℃, Tc ℃, and Ta≤Tb-10 is preferred.In addition, Tc≤Tb is for more preferably.Ta≤Tb-10, and Tc≤Tb is for more preferably.

It is good to desire to make orientation angle to distribute, and the film heat-up rate of step B is that the scope of 0.5～10 ℃/s is preferred.

The extension time of step B is, 80 ℃, desire to make size changing rate to diminish under the 90%RH condition, with the short period of time more preferably.But, by the viewpoint of the homogeneity of film, the required extension time range of regulation minimum.The scope that is specially 1～10 second is for preferred, and 4～10 seconds for more preferably.In addition, the temperature of step B is 40～180 ℃, more preferably is 100～160 ℃.

In the above-mentioned tentering step, heat-conduction coefficient can be certain or through variation person.As heat-conduction coefficient with 41.9～419 * 10 ³J/m ²The scope of hr is preferred.More preferably 41.9～209.5 * 10 ³J/m ²The scope of hr most preferably is 41.9～126 * 10 ³J/m ²The scope of hr.

Desire to make 80 ℃, the dimensional stability under the 90%RH condition is good, but carries out under the extension speed certain speed of the cross direction of above-mentioned steps B or make its variation.Serves as preferred as extension speed with 50～500%/min, more preferably is 100～400%/min, and 200～300%/min is for most preferably.

In the tentering step, by the viewpoint that the homogeneity of film improves, the cross direction temperature distribution of environment is less be preferred, and the temperature distribution of the cross direction in the tentering step serves as preferably with ± 5 ℃ with in, ± 2 ℃ with interior for more preferably, ± 1 ℃ with interior for most preferably.Distribute by reducing said temperature, can expect that the temperature distribution of film cross direction reduces.

In step C, desire suppresses dimensional change can relax cross direction for preferred.The scope that is specially for the wide one-tenth 95～99.5% of the wide adjustment film of the film of preceding step is preferred.

After the tentering step process, drying step (hereinafter referred to as step D1) is set again for preferred.Under 50～140 ℃, carry out to preferably.More preferably 80～140 ℃ scope most preferably is 110～130 ℃ scope.

Among the step D1, by the viewpoint that the homogeneity of film improves, the cross direction temperature distribution of environment is less be preferred, with ± 5 ℃ serve as preferably with in, ± 2 ℃ with interior for more preferably, ± 1 ℃ with interior for most preferably.

Film delivery tension force among the step D1 can be subjected to the physical property of rubber cement, when peeling off and the residual solvent amount during step D0, the influences such as temperature of step D1, but serve as preferred with 80～200N/m, with 140～200N/m for more preferably.With 140～160N/m for most preferably.

To desire preventing that the film to the carrying direction extends to purpose among the step D1, tension cutting roller (tension cut roll) is set for preferred.The dry back of ending is provided with cutting machine and cuts away the end before batching, can obtain good rolled state.

For polaroid of the present invention, when improving display characteristic, desire gives hysteresis to film, preferably cellulose ester film is extended the hysteresis of may command cellulose ester film toward cross direction.

Reach purpose of the present invention in advance, be specially the phase-contrast film that uses polaroid of the present invention, the thickness of 30 μ m by the casting film manufactured～below the 150 μ m is preferred, this be from take into account effect of the present invention and thin film physics intensity, with the viewpoint of the face of manufacturing.For the thickness of this film, more preferably be 40 μ m～following scope of 120 μ m.

In addition, in the cellulose ester film of the present invention, the spring rate of preferred cross direction is more than the spring rate of curtain coating direction, and the spring rate of cross direction becomes 1.0～1.5 times of spring rate of the curtain coating direction for more preferably.The spring rate of cellulose ester film can be controlled by extent, so by adjusting the extension ratio of cross direction and curtain coating direction aptly, the ratio of the spring rate of may command cross direction and curtain coating direction.

(polaroid)

Explain for polaroid of the present invention.

Polaroid can be produced by general method.The preferred practice is, the inside side of alkali soap processing cellulose ester film of the present invention, impregnated in the iodine solution cellulose ester film of this processing and the light polarizing film (polarizer) that makes after extending, on the one side at least of this light polarizing film, use fully saponified type polyvinyl alcohol water solution to fit.Another side also uses cellulose ester film of the present invention, or uses other polarizer protection film.For cellulose ester film of the present invention; the polarizer protection film that is used in another side is preferably aforementioned phase-contrast film, or the polarizer protection film that has phase-contrast film concurrently that preferably has an incorgruous layer of formed optics behind the liquid crystalline cpds such as directed disk liquid crystal, rod shaped liquid crystal, cholestric liquid crystal is for preferred.The for example special method of opening the 2003-98348 record forms optical anisotropy's layer.By using the combination of tieing up with cellulose ester film of the present invention, can obtain having the polaroid that good, the stable angle of visibility in plane enlarges effect.

Can use another polarizer protection film of thickness 40～120 μ m at the reverse side of the light polarizing film of seizing cellulose ester film of the present invention on both sides by the arms; as commercially available cellulose ester film, can enumerate コ ニ カ ミ ノ Le Star Network KC8UX2M, KC4UX, KC5UX, KC4UY, KC8UY, KC12UR, KC8UCR-3, KC8UCR-4, KC8UCR-5, KC8UX-RHA (the above Konica minolta (strain) of being makes) etc. for preferred.

Light polarizing film as the main composition key element of polaroid is, the assembly of the light of the partial wave face by certain orientation only, known now representative light polarizing film is the polyethenol series polarizing film, and this is that polyvinyl alcohol film is through the plain tinter of iodine with the dichroic dye tinter.Light polarizing film is for polyvinyl alcohol water solution system film, with this through one extend poststaining or dyeing after again through an extension, be preferably use and carry out the weather resistance processor with the plain compound of boron.This forms polaroid after one side of the cellulose ester film of the present invention of fitting above light polarizing film.Be preferably by fully saponified polyvinyl alcohol etc. and fit as the aqueous adhesive of principal constituent.

Light polarizing film is for extending toward a direction of principal axis (being generally length direction), and when polaroid was positioned over hot and humid environment, bearing of trend (being generally length direction) can shorten, and extends toward being vertical direction (being generally cross direction) with bearing of trend.The thickness of polarizer protection film is thin more, and the expansion and contraction of its polaroid is big more, and the shrinkage that is in particular the bearing of trend of light polarizing film can become big.Generally desire to make the curtain coating direction (MD direction) of the bearing of trend and the polarizer protection film of light polarizing film to fit, when carrying out the filming of polarizer protection film, will suppress the expansion and contraction of curtain coating direction especially, this is very important.Cellulose ester film of the present invention is because of excellent size stability, so be applicable on such polarizer protection film.

That is, by 60 ℃, the endurance test under the 90%RH condition is not learnt can increase wavy spot, and the inboard has the polaroid of phase-contrast film, and the good identification of the angle of visibility characteristic no change after the endurance test can be provided.

(display unit)

By display unit that polaroid of the present invention is packed into, can produce the good display unit of the present invention of all identifications.Cellulose ester film of the present invention is preferred applicable to the LCD of various type of drive such as reflection-type, infiltration type, semi-transmission type LCD or TN type, STN type, OCB type, HAN type, VA type (PVA type, MVA type), IPS type.Various display unit such as in addition, cellulose ester film dimension of the present invention is good for planarity, plasma display, Field Emission Display, OLED display, inorganic EL indicating meter, Electronic Paper.In the special big picture display device more than picture is 30 types, have color spot or wave spot less, and the long-time back eyes of appreciating also can tired effect.

Embodiment

Below, enumerating embodiment and specify the present invention, the present invention is not subjected to the restriction of these embodiment.

Embodiment 1

" manufacturing of cellulose ester film 101 "

Employed cellulose ester, softening agent (wherein aforementioned aromatic end ester cpds and polyol ester compound are also represented a kind of of softening agent), UV light absorber, particulate are as shown in table 1.

[table 1]

Resin

Cellulose ester	Substitution value		Mn	Mw/Mn
					A	Ethanoyl: 2.0	Propenyl: 0.7	70000	2.4
B	Ethanoyl: 1.7	Propenyl: 0.9	54000	2.9
					C	Ethanoyl: 1.65	Propenyl: 0.9	55000	2.7
D	Ethanoyl: 1.6	Propenyl: 0.9	40000	2.5
					E	Ethanoyl: 1.45	Propenyl: 1.1	53000	2.4
F	Ethanoyl: 2.4		50000	2.4
					G	Ethanoyl: 1.5	Propenyl: 0.5	55000	2.4

Softening agent

A	Triphenyl
		B	Ethyl phthaloyl ethyl hexanol acid esters
C	Aromatic series terminal ester sample No.1
		D	The trimethylolpropane tris benzoic ether
E	Aromatic series terminal ester sample No.3
		F	Aromatic series terminal ester sample No.13

UV light absorber

A	TINUVIN326 (チ ヌ PVC Application) (チ バ ス ペ シ ヤ Le テ イ ケ ミ カ Le ズ company)
		B	TINUVIN109 (チ バ ス ペ シ ヤ Le テ イ ケ ミ カ Le ズ company)
C	TINUVIN171 (チ バ ス ペ シ ヤ Le テ イ ケ ミ カ Le ズ company)
		D	UV light absorber 1

Particulate

AEROSIL R972V (Japanese Aerosil system)

[changing 7]

UV light absorber 1

＜particle dispersion liquid 〉

Particulate 11 mass parts

Ethanol 89 mass parts

With above-mentioned mix 50 minutes with dissolver (Dissolver) after, disperse with マ Application ト Application go one リ Application.

＜particulate annex solution 〉

In the solution tank that is placed with methylene dichloride, add cellulose ester B, it is dissolved fully after, this is filtered with the long-pending filter paper No.244 of peace that pacifies long-pending filter paper (strain) and make.Fully under the cellulose ester solution after the agitation and filtration, slowly add particle dispersion liquid in this.And the particle diameter of secondary particle disperses in pulverising mill.This Off ア イ Application メ Star ト (Fine met) NF that makes with the smart line of Japan (strain) is filtered, modulate the particulate annex solution.

Methylene dichloride 99 mass parts

Cellulose ester B 4 mass parts

Particle dispersion liquid 11 mass parts

Modulate the main rubber cement liquid of following composition.At first add methylene dichloride and ethanol in the dissolved under pressure groove.In the dissolved under pressure groove that is placed with solvent, stir and add cellulose ester B down, heating, it is dissolved fully under stirring after, add softening agent and UV light absorber again and make its dissolving.This is filtered with the long-pending filter paper No.244 of the peace of pacifying long-pending filter paper (strain) making, modulate main rubber cement liquid.

Add and become owner of after rubber cement liquid 100 mass parts and particulate annex solution 2 mass parts with inner stirrer (inline mixer) (mixing machine in the eastern レ silent oscillation pipe, Hi-Mixer, SWJ) carry out thorough mixing, use the conduction band casting device then, on the support of the stainless steel conduction band of wide 2m, carry out the homogeneous curtain coating.On the support of stainless steel conduction band, evaporating solvent to residual solvent amount is till 110%, is peeled off by stainless steel conduction band support.Bestow tension force when peeling off and extend to 1.02 times of extension ratios toward longitudinal direction (MD), control the web two ends with tenter machine then, extend to 1.3 times of extension ratios toward wide hand (TD) direction, the residual solvent when extending beginning is 30%.After the extension, keep this width between the several seconds, untie wide maintenance behind the tension force of mitigation cross direction, carry out 30 minutes the drying of transporting again in the 3rd arid region that is set at 125 ℃, make and have wide 1.5m, and the end is wide to be 1cm, the cellulose ester film of the present invention 101 of the thickness 40 μ m of the annular knurl processing of height 8 μ m.

The composition of＜main rubber cement liquid 〉

Methylene dichloride 300 mass parts

Ethanol 57 mass parts

Cellulose ester B 100 mass parts

Softening agent (C) 5.5 mass parts

Softening agent (D) 5.5 mass parts

UV light absorber (A) 0.4 mass parts

UV light absorber (B) 0.7 mass parts

UV light absorber (C) 0.6 mass parts

Beyond the extension ratio of resin, softening agent, UV light absorber, drying temperature, cross direction changes to shown in table 2,3, obtain cellulose ester film 102～110 of the present invention under other is same as described above, and cellulose ester film 201,202 relatively.

[table 2]

Cellulose ester film No.	Main rubber cement: particulate annex solution mixture ratio		Main rubber cement is formed								The system film	Remarks
													Main rubber cement	The particulate annex solution	Resin	Softening agent		UV light absorber			Methylene dichloride	Ethanol	Drying temperature
	101	100	2	B(100kg)	C(5.5kg)	D(5.5kg)	A(0.4kg)	B(0.7kg)	C(0.6kg)	300kg	57kg													120℃	The present invention
102												100	2	C(100kg)	C(5.5kg)	D(5.5kg)	A(0.4kg)	B(0.7kg)	C(0.6kg)	300kg	57kg	120℃	The present invention
	103	100	2	A(100kg)	C(5.5kg)	D(5.5kg)	D(3.0kg)	-	-	300kg	57kg													125℃	The present invention
104												100	2	B(100kg)	D(5.5kg)	E(5.5kg)	D(3.0kg)	-	-	300kg	57kg	125℃	The present invention
	105	100	2	D(100kg)	D(5.5kg)	E(5.5kg)	D(3.0kg)	-	-	300kg	57kg													125℃	The present invention
106												100	2	F(100kg)	D(5.5kg)	E(5.5kg)	D(3.0kg)	-	-	300kg	57kg	125℃	The present invention
	107	100	2	E(100kg)	C(5.5kg)	D(5.5kg)	D(3.0kg)	-	-	300kg	57kg													125℃	The present invention
108												100	2	E(100kg)	D(5.5kg)	E(5.5kg)	A(0.4kg)	B(0.7kg)	C(0.6kg)	300kg	57kg	125℃	The present invention
	109	100	2	G(100kg)	C(5.5kg)	D(5.5kg)	D(3.0kg)	-	-	300kg	57kg													125℃	The present invention
110												100	2	C(100kg)	F(5.5kg)	D(5.5kg)	D(3.0kg)	-	-	300kg	57kg	125℃	The present invention
	201	100	2	A(100kg)	A(9.5kg)	B(2.2kg)	A(0.4kg)	B(0.7kg)	C(0.6kg)	300kg	57kg													100℃	Comparative example
202												100	2	C(100kg)	A(9.5kg)	B(2.2kg)	A(0.4kg)	B(0.7kg)	C(0.6kg)	300kg	57kg	100℃	Comparative example

[table 3]

Cellulose ester film No.	Rt value (23 ℃)		Rt humidity changes the change value	Ro value (23 ℃)	The wet swelling coefficient		Extend (doubly)	Thickness (μ m)	Remarks
										Rt(b)	Rt(c)	Rt(a)	1/％RH
	MD	TD
			101		130	122							8	39	3.00×10 -5	2.80×10 -5	1.3	40	The present invention
102	130	119		11			41	2.95×10 -5	2.75×10 -5	1.25	40	The present invention
			103		132	119							13	39	3.00×10 -5	2.80×10 -5	1.2	80	The present invention
104	130	123		7			40	3.05×10 -5	2.76×10 -5	1.3	40	The present invention
			105		131	122							9	39	2.54×10 -5	2.35×10 -5	1.25	40	The present invention
106	132	120		12			39	2.95×10 -5	2.75×10 -5	1.2	40	The present invention
			107		130	121							9	39	2.84×10 -5	2.57×10 -5	1.25	40	The present invention
108	131	122		9			41	2.90×10 -5	2.68×10 -5	1.25	40	The present invention
			109		135	125							10	43	2.90×10 -5	2.68×10 -5	1.2	40	The present invention
110	131	122		9			41	2.91×10 -5	2.68×10 -5	1.25	40	The present invention
			201		142	118							24	41	4.10 ×10 -5	3.71×10 -5	1.3	80	Comparative example
202	140	121		19			39	4.05×10 -5	3.68×10 -5	1.25	40	Comparative example

For each sample of gained, the hysteresis change of measuring the wet swelling coefficient of MD (curtain coating direction), the TD (cross direction) of film, humidity is changed with following main points.

(wet swelling coefficient)

Wet swelling coefficient (1/%RH) is represented by following formula.L4 represents to be changed to 23 ℃ of following relative humidity (RH4 in following, in the present embodiment for 80%RH) time film test portion length (mm), L0 represent that (23 ℃, film test portion life size (mm) 55%RH), RH0 represent that standard relative humidity (%RH), RH4 represent above-mentioned relative humidity (%RH) through changing to standard state.

β＝{(L4-L0)/L0}/(RH4-RH0)

The wet swelling coefficient is the dimensional change of every relative humidity 1%, changes big film or changes less film by humidity change expression.Among the present invention, the wet swelling coefficient is 6 * 10 ^-5(1/%RH) following is preferred, 3 * 10 ^-5(1/%RH) following for more preferably, 1 * 10 ^-5(1/%RH) following for more preferably.

(hysteresis that changes for humidity changes)

Each humidity by prepared cellulose ester film is tried to achieve each hysteresis, tries to achieve Rt (a) by this value.

Rt (a) change is, Rt (b) is 23 ℃, after carrying out damping in 5 hours under the 20%RH, with Rt value measured under the environment as Rt (b), R (c) is that identical film is afterwards at 23 ℃, carry out under the 80%RH more than 5 hours trying to achieve Rt (c) with determining the Rt value under the environment after the damping, try to achieve Rt (a) by formula down.

Rt(a)＝|Rt(b)-Rt(c)|

And the test portion after damping is measured under the 55%RH environment once more in 23 ℃, finds that this change is reversible change.

The above-mentioned assessment result of embodiment 1 prepared cellulose ester film is as shown in table 3.

Cellulose ester film 101～110 of the present invention is compared with comparing film, and it is less because of the wet swelling coefficient, so be as the dimensional change relevant with temperature humidity, the less good polarizer protection film of hysteresis Rt change.In addition; in the making of cellulose ester film 101; softening agent C is changed to the aromatic series terminal ester sample No.2 and 4～12 with amount; in addition; with each cellulose ester film that the same procedure of cellulose ester film 101 makes, all has the good results of the polarizer protection film identical with cellulose ester film 101.

Embodiment 2

" making of polaroid "

With thickness is that the PVA (PVOH) FILM of 120 μ m is carried out an extension (110 ℃ of temperature, extension ratio are 5 times).This be impregnated in by the aqueous solution that water became of the potassiumiodide of the iodine of 0.075g, 5g, 100g 60 seconds, this be impregnated in the potassiumiodide of 6g, the boric acid of 7.5g, 68 ℃ the aqueous solution that water became of 100g again.This is obtained light polarizing film after washing, drying.

Secondly, according to following step 1～5 make light polarizing film and aforementioned fibers cellulose ester film 101～110,201,202, with the polaroid of inboard applying as the following cellulose ester film of polarizer protection film.

Dipping is 90 seconds in the sodium hydroxide solution of step 1:60 ℃ 2 moles/L, washes after drying then, and the face that obtains fitting with polarizer is through the saponified cellulose ester film.

Step 2: aforementioned light polarizing film was flooded 1～2 second in the poly (vinyl alcohol) binder groove of solids component 2 quality %.

Step 3: the superfluous tackiness agent that is attached to light polarizing film is removed in wiping lightly in step 2, and this is disposed on the cellulose ester film treated in the step 1.

Step 4: in the step 3 laminated cellulose ester film 101～110,201,202 and light polarizing film and inboard cellulose ester film, with pressure 20～30N/cm ², travelling speed was about under 2m/ minute fits.

In step 5:80 ℃ the drying machine, the test portion of fitting in the prepared light polarizing film of step 4 and cellulose ester film 101～110,201,202 and inboard cellulose ester film made polaroid 101～110,201,202 after the drying through 2 minutes.

(manufacturing of inboard cellulose ester film)

＜particle dispersion liquid 〉

Particulate 11 mass parts

Ethanol 89 mass parts

With above-mentioned mix 50 minutes with dissolver (Dissolver) after, disperse with マ Application ト Application go one リ Application.

＜particulate annex solution 〉

In the solution tank that is placed with methylene dichloride, add cellulose ester B, it is dissolved fully after, this peace of making of the long-pending filter paper (strain) of peace is amassed filter paper No.244 filters.Fully the cellulose ester solution after the agitation and filtration simultaneously, slowly adds above-mentioned particle dispersion liquid in this.And the particle diameter of secondary particle disperses in pulverising mill, makes it become the particulate of prescribed level.This Fine met NF that makes with the smart line of Japan (strain) is filtered, modulate the particulate annex solution.

Methylene dichloride 99 mass parts

Cellulose ester B 4 mass parts

Particle dispersion liquid 11 mass parts

Modulate the main rubber cement liquid of following composition.At first add methylene dichloride and ethanol in the dissolved under pressure groove.In the dissolved under pressure groove that is placed with solvent, add cellulose ester (the acetyl substitution value is 2.9, and Mn is 80000, and Mw/Mn is 2.4) down in stirring.This after under heating, the stirring it being dissolved fully, is added softening agent and UV light absorber and also make its dissolving.This long-pending filter paper No.244 of peace that makes of the long-pending filter paper (strain) of peace is filtered, modulate main rubber cement liquid.

Add and become owner of after rubber cement liquid 100 mass parts and particulate annex solution 5 mass parts with inner stirrer (mixing machine in the eastern レ silent oscillation pipe, Hi-Mixer, SWJ) carry out thorough mixing, next uses the conduction band casting device, carries out the homogeneous curtain coating on the support of the stainless steel conduction band of wide 2m.On the support of stainless steel conduction band, evaporating solvent to residual solvent amount is till 110%, is peeled off by stainless steel conduction band support.Bestow tension force when peeling off and extend to 1.1 times of extension ratios, secondly control the web two ends, extend to 1.1 times of extension ratios toward wide hand (TD) direction by tenter machine toward longitudinal direction (MD).After the extension, keep this width between the several seconds, untie wide maintenance behind the tension force of mitigation cross direction, carry out 30 minutes the drying of transporting again in the 3rd arid region that is set at 125 ℃, make and have wide 1.5m, and the end is wide to be 1cm, the cellulose ester film of the present invention of the thickness 80 μ m of the annular knurl processing of height 8 μ m.

The composition of＜main rubber cement liquid 〉

Methylene dichloride 450 mass parts

Ethanol 30 mass parts

(the acetyl substitution value is 2.9 to cellulose ester, and Mn is

80000, Mw/Mn is 2.4) 100 mass parts

Softening agent (C) 2.2 mass parts

Softening agent (D) 9.5 mass parts

UV light absorber (A) 0.4 mass parts

UV light absorber (B) 0.7 mass parts

UV light absorber (C) 0.6 mass parts

Light leakage quantity, revision property (rework) for each polaroid of gained are measured.As shown in table 4.

(light leakage quantity (weather resistance)

2 polaroids making are configured to the polarisation orthogonal, use the spectrophotometer U3100 of (strain) Hitachi system, determine the transmitance (T1) of 590nm.And 2 polaroids are all after carrying out under 80 ℃ of conditions handling in 500 hours, and the transmitance (T2) that determines when being configured to the polarisation orthogonal same as described above changes the transmitance before and after the thermal treatment and to investigate, and determine the light leakage quantity according to formula down.

Light leakage quantity (%)=T2 (%)-T1 (%)

The light leakage quantity is not have practical problem at 0～5% o'clock, but be 0～4% o'clock for preferred, more preferably 0～3%, 0～1 (%) be preferably special.

(revision property (rework, polaroid yield))

The polaroid that makes is cut out the square that is cut into 20cm * 20cm size, use acrylic adhesive and glass substrate to fit.Secondly the polaroid of fitting is peeled off by glass with the 5N brute force by the angle part.This operation uses 100 polaroids to carry out for the sample of a kind, and calculating has slight crack on polaroid, and the polaroid number that can't peel off fully.Revision property is with following benchmark scoring.

Zero: 0～5

Zero △: 6～10

△: 11～15

*: more than 16

Revision property is that the △ level does not have when above and practically goes up problem, but zero △ level above be preferred, during zero level be the spy preferably.

[table 4]

Polaroid	Light leaks	The polaroid yield	Liquid crystal indicator		Remarks
						The angle of visibility deterioration	Identification
			Polaroid 101	1.5				○	○	○	The present invention
Polaroid 102	1.5	○			○	○	The present invention
			Polaroid 103	1.7				○	○	○	The present invention
Polaroid 104	0.9	○			○	○	The present invention
			Polaroid 105	1.1				○	○	○	The present invention
Polaroid 106	1.5	○			○	○	The present invention
			Polaroid 107	1.8				○	○	○	The present invention
Polaroid 108	1.2	○			○	◎	The present invention
			Polaroid 109	1.2				○	○	○	The present invention
Polaroid 110	1.1	○			○	○	The present invention
			Polaroid 201	3.5				○△	×	△	Comparative example
Polaroid 202	3.9	△			△	△	Comparative example

Learn that by last table polaroid 101～110 of the present invention is for having the polaroid of good revision, light leakage property.In addition, when making polaroid 101, beyond the softening agent C of employed cellulose ester film 101 replaced with the aromatic series terminal ester sample No.2 and 4～12 with amount, other and polaroid 101 similarly produced each polaroid, all had the good results identical with polaroid 101.

Embodiment 3

" making of liquid crystal indicator "

Carry out liquid crystal panel such as following making that angle of visibility is measured, assessment is as the characteristic of liquid crystal indicator.

The two sides polaroid of fitting in advance of strip off SONY system 20 escope KLV-20AP2 fits in the above-mentioned polaroid that makes 101～110,201,202 on each liquid crystal born of the same parents's the glass surface.

At this moment, the applying direction of this polaroid is, the face of aforementioned fibers cellulose ester film 101～110,201,202 becomes liquid crystal born of the same parents side, and absorption axes is carried out under person and the same direction of polaroid of fitting in advance, makes liquid crystal indicator 101～110,201,202 respectively.In addition, employed polaroid uses from performance and is easy to generate the part that the end branch of the rectangular cellulose ester film of deviation cuts out.

(angle of visibility deterioration)

23 ℃, the EZ-Contrast 160D that the environment of 55%RH uses ELDIM company to make down carries out the mensuration of liquid crystal indicator angle of visibility.Again in 23 ℃ of 20%RH, and under the environment of 23 ℃ of 80%RH, assess with following benchmark after measuring the angle of visibility of prepared liquid crystal indicator (commercially available panel+do certainly ellipsoidal polarizing plate).At last, the environment of 23 ℃ of 55%RH is remake an angle of visibility measures, confirm aforementioned survey periodic be changed to reversible change.And these are determined at liquid crystal indicator and measure after this environment is placed 5 hours down.

Zero: do not have visual field angular variable fully

△: find the angle of visibility change

*: the angle of visibility change is very big

(assessment of identification)

For above-mentioned prepared each liquid crystal indicator, place after 100 hours under 60 ℃ of 90%RH conditions, return to 23 ℃, 55%RH.When its result observes display unit surperficial, for the good use of planarity polaroid of the present invention, observe trickle wavy spot on the display unit of comparative example, and have the phenomenon of eyestrain after viewing and admiring for a long time.

◎: do not observe wavy spot on the surface fully

Zero: observe wavy spot on the surface slightly

△: observe trickle wavy spot on the surface slightly

*: observe trickle wavy spot on the surface

The assessment result of liquid crystal indicator 101～110,201,202 is shown in above-mentioned table 4.Learn the liquid crystal indicator that liquid crystal indicator 101～110 of the present invention is the angle of visibility no change, identification is good by the result.In addition, when making liquid crystal indicator 101, the softening agent C of employed cellulose ester film 101 changes to respectively with beyond the aromatic series terminal ester sample No.2 and 4～12 that measures, other and similarly prepared each liquid crystal indicator of liquid crystal indicator 101 all show the good results identical with polaroid 101.

Utilizability on the industry

The invention provides a kind of cellulose ester film that changes the invertibity change of caused hysteresis because of humidity that improves, and, use this cellulose ester film, on light leakage, angle of visibility characteristic, identification good polarizer and liquid crystal indicator.

Claims (11)

1. cellulose ester film is characterized by and contains as the represented compound of following general formula (1):

General formula (1) B-(G-A) n-G-B

In the formula, B represents benzene monocarboxylic acid residue, G represents alkane diol residue or the aryl-diol residue of carbon number 6～12 or the oxyalkylene diol residue of carbon number 4～12 of carbon number 2～12, A represents the alkylene dicarboxylic acids residue of carbon number 4～12 or aryl dicarboxylic acid's residue of carbon number 6～12, and n represents the integer more than 1.

2. cellulose ester film as claimed in claim 1, wherein the molecular weight of the compound of aforementioned formula (1) is 300～2000.

3. cellulose ester film as claimed in claim 1 wherein further contains the polyol ester based compound.

4. cellulose ester film as claimed in claim 1, wherein the aforementioned fibers cellulose ester film contains the cellulose ester that satisfies following formula (I), (II) simultaneously:

(I)2.1≤X+Y≤2.9

(II)1.0≤X≤2.9

But X represents the substitution value of ethanoyl, and Y represents the substitution value of lipid acid ester group.

5. cellulose ester film as claimed in claim 1, wherein the width of aforementioned fibers cellulose ester film is 1.4～4m.

6. cellulose ester film as claimed in claim 1, the represented Ro of wherein following formula is below the above 300nm of 20nm under 23 ℃, 55%RH condition, the represented Rt of following formula is below the above 400nm of 70nm under 23 ℃, 55%RH condition:

Ro＝(nx-ny)×d

Rt＝((nx+ny)/2-nz)×d

In the formula, nx, ny, nz respectively represent main shaft x, the y of indicatrix, the specific refractory power of z direction, and nx, ny represent the specific refractory power of direction in the aforementioned fibers cellulose ester film face, and nz represents the specific refractory power of aforementioned fibers cellulose ester film thickness direction; In addition, nx 〉=ny, d represent aforementioned fibers cellulose ester film thickness (nm).

7. a polaroid is characterized by in 1 of polarizer be provided with cellulose ester film as claimed in claim 1 at least.

8. polaroid as claimed in claim 7 wherein is located at protective film as polaroid on 1 of aforementioned polarizer with aforementioned cellulose ester film at least.

9. polaroid as claimed in claim 7 wherein is located at as phase-contrast film on 1 of aforementioned polarizer with aforementioned cellulose ester film at least.

10. polaroid as claimed in claim 7, wherein in the aforementioned fibers cellulose ester film, the represented Ro of following formula is below the above 300nm of 20nm under 23 ℃, 55%RH condition, the represented Rt of following formula is below the above 400nm of 70nm under 23 ℃, 55%RH condition:

Ro＝(nx-ny)×d

Rt＝((nx+ny)/2-nz)×d

In the formula, nx, ny, nz respectively represent main shaft x, the y of indicatrix, the specific refractory power of z direction, and nx, ny represent the specific refractory power of direction in the aforementioned fibers cellulose ester film face, and nz represents the specific refractory power of aforementioned fibers cellulose ester film thickness direction; In addition, nx 〉=ny, d represent aforementioned fibers cellulose ester film thickness (nm).

11. a liquid crystal indicator is characterized by and uses polaroid as claimed in claim 7.

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