CN1315663A

CN1315663A - Polarizing filter protecting film

Info

Publication number: CN1315663A
Application number: CN 01103872
Authority: CN
Inventors: 辻本忠宏
Original assignee: Fujifilm Corp
Current assignee: Fujifilm Holdings Corp; Fujifilm Corp
Priority date: 2000-03-31
Filing date: 2001-03-16
Publication date: 2001-10-03

Abstract

PROBLEM TO BE SOLVED: To provide a protective film for a polarizing plate capable of enhancing adhesive property between a polarizing element and the protective film without lowering polarizing performance, excellent and improving its productivity in the polarizer used for a liquid crystal display device or the like. SOLUTION: The polarizing plate comprises the polarizing 1 on the both sides of which the protective films 2 for polarizer are laminated with an adhesive. The protective film 2 has 3-10 g/m2.24 hr. moisture vapor permeation rate and 0.01-1.5% equilibrium moisture content at 25 deg.C, 60% RH (relative humidity) and contains >=80% cellulose ester, 1-20% hydrophobic plasticizer and 0.001-5% deterioration preventing agent. A protective film is capable of enhancing adhesive property between a polarizing element and the protective film, lowering polarizing performance, and improving its productivity in the polarizer used for a liquid crystal display device.

Description

Polarizing filter protecting film

The present invention relates to a kind of polarizing filter protecting film that is used for the polarized light piece of liquid crystal indicator etc.

Used polarized light piece on liquid crystal indicator etc., as shown in Figure 1, by polarization element 1 and its two sides (or single face) set polarizing filter protecting film 2 constitute bonding this polarization element 1 of blended rubber stick and polarizing filter protecting film 2.Usually; use the absorption iodine on polyethenol series film etc. or the film of bitintability dyestuff as polarization element 1, and use cellulose esters films, polycarbonate-based film, acrylic compounds film, polyester film, polyolefins film, norborene class film etc. as polarizing filter protecting film 2.

In such polarized light piece, when the rate of perviousness of polarized light diaphragm 2 is big, humidity resistance variation then, and in polarization element 1, a lot of iodide ions take place dissociate, separate iodine etc., reduced the polarized light performance.Therefore, as the technical scheme that prevents that humidity resistance is aging, for example opened in the clear 59-159109 communique the spy, once proposing moisture permeability is 10g/m in the past ²High molecular compound film below 24 hours is made the method for polarizing filter protecting film, and opens in the flat 8-5386 communique the spy, once proposes being 200g/m at 80 ℃, 90%RH moisture permeability ²24 hours, the following diaphragm of 100 μ m was attached to the polarized light piece on the diaphragm.

In addition; open in the flat 8-171016 communique the spy; proposition makes the manufacture method of the polarized light piece that Bayes's value of the diaphragm that is made of the primary cellulose acetate sheet do not rise; and open in the flat 5-119210 communique the spy, propose to make the manufacture method that does not produce the polarized light piece of be full of cracks at polarization photosensitiveness thin layer.

But when the rate of perviousness of polarizing filter protecting film was big, then as above-mentioned reduction polarized light performance, and rate of perviousness was too small also has problems.Just, on the two sides of polarization element or during the bonding polarizing filter protecting film of single face,, cause bonding bad problem because tackifier is dry slow.

Therefore, when the rate of perviousness of polarizing filter protecting film was excessive, then humidity resistance was poor, and reduced the polarized light performance, and had served as hour, then the cementability variation.

In order to address the above problem, the purpose of this invention is to provide a kind of polarizing filter protecting film.This polarized light diaphragm does not make the polarized light performance reduce, and has the good polarization element and the cementability of polarizing filter protecting film, and boost productivity by the rate of perviousness at appropriate area control polarizing filter protecting film.

In order to address the above problem, the present inventor carries out with keen determination research to the moisture-penetrability of polarizing filter protecting film, and discovery can be satisfied the scope of the rate of perviousness of the polarized light performance of the scope that can allow as goods and cementability two aspects, and then has finished the present invention.

That is, polarizing filter protecting film of the present invention, it is characterized in that constituting rate of perviousness is 3-10g/m ²24 hours.

In polarizing filter protecting film of the present invention, be 3g/m by making rate of perviousness ²More than 24 hours, the moisture that can be suitably sees through tackifier promotes dry, therefore make cementability good, in addition by being rate of perviousness 10g/m ²In 24 hours,, keep good polarized light performance even under the environment that high temperature wets more, also can suppress moisture and penetrate into polarization element.

The rate of perviousness of polarizing filter protecting film of the present invention is 3-10g/m ²24 hours, that desirable was 4-8g/m ²24 hours.When rate of perviousness less than 3g/m ²24 hours, under the poorest situation of cementability, produce and peel off, and reduce throughput rate.Surpass 10g/m and work as rate of perviousness ²24 hours, then make the humidity resistance variation of polarization element, can not keep suitable polarized light performance.

For the rate of perviousness of polarizing filter protecting film is adjusted to above-mentioned scope, thickness that can be by polarizing filter protecting film, the kind of hydrophobic additive with and addition etc. adjust.The thickness of polarizing filter protecting film is that 20-200 μ m is desirable, and is preferably 40-150 μ m.When thickness during, then be difficult to rate of perviousness is adjusted into 10g/m less than 20 μ m ²Below 24 hours, and when thickness surpasses 150 μ m, then be difficult to rate of perviousness is adjusted into 3g/m ²More than 24 hours.

Is that plastifier is representative as hydrophobic plasticizer with phosphate.(it is plastifier that I a) reaches the representational phosphate of (I b) expression to available following formula.

(Ⅰa)???????(Ⅰb)

(I a) reaches in (I b), R in formula ¹, R ², R ³, R ⁴, R ⁵, R ⁶And R ⁷Be respectively alkyl (comprising naphthenic base), aryl or aralkyl.Also but the angle base has substituting group.The carbon number of alkyl is that 1-12 is desirable.Example as alkyl can be enumerated methyl, ethyl, butyl, cyclohexyl and octyl group.Example as aryl can be enumerated phenyl.Example as aralkyl can be enumerated benzyl.Can enumerate alkyl (for example, methyl), aryl (for example, phenyl), alkoxy (for example, methoxyl, butoxy) and aryloxy group (for example, phenoxy group) as above-mentioned substituting group.In formula (I b), R ⁸Connection base for selected divalence from alkylidene, arylene, sulfonic group and their combination.N is the integer more than 1, and is that 1-10 is desirable.

At phosphate is in the example of plastifier, comprises triphenyl phosphate, phosphoric acid biphenyl diphenyl ester, tricresyl phosphate, octyl diphenyl phosphate, triethyl phosphate and tributyl phosphate.In addition, have also that to utilize carboxylate be the situation of plastifier.In being the example of plastifier, carboxylate comprises dimethyl phthalate, phthalandione oxalic acid, Dibutyl phthalate, dioctyl phthalate, phthalandione ethylhexyl, phthalandione dimethoxy ethyl ester, triacetyl glycerine, fourth phthaloyl butyl glycol ester, second phthaloyl ethohexadiol ester, first phthalandione ethohexadiol ester and triacetin.In addition, as citrate citric acid acetyl triethyl (OACTE), tributyl citrate (OACTB) etc. are arranged, butyl oleate (BO), linoleic acid first acetonyl ester (MAL), dibutyl sebacate (DBS), various trimellitates etc. are arranged as other the example of carboxylate.Can enumerate the neighbour or to toluene second sulfanilamide (SN) as the example of other low molecular plastifier.

In addition, can be the ester of trihemellitic acid or pyromellitic acid and phosphate that plastifier share also.The ester of trihemellitic acid or pyromellitic acid has and prevents that phosphate from being the effect that the bleeding of plasticity is moved.Opening in the flat 5-5047 communique the spy for these sour esters has report.

Addition as hydrophobic plasticizer is that 1-20% is desirable, and is preferably 5-15%.When addition less than 1% the time, then can not rate of perviousness be diminished.And when addition surpassed 20%, it was too small then rate of perviousness to be become.

In polarizing filter protecting film 25 ℃, the equilibrium humidity of 60%RH are that 0.01-1.5% is desirable, and are preferably 0.2-1.2%.When equilibrium humidity less than 0.01 the time, then fragility increases, and cutting off or flinders taking place or peel off stacked polarized light piece during punching press, causes that quality descends or throughput rate reduces.In addition, because the rising with voltage of static is adsorbed foreign matter in the mill easily or is diminished thin slice and handles property.

In addition, when equilibrium humidity surpassed 1.5%, the polarized light performance that then may hinder the polarization element of polarized light piece particularly under the situation of iodine absorption-type polarization element, had the problem of reduction because of the polarized light of iodine decolouring.And, because change in size produces uneven in the demonstration of LCD plate.

Can use the film of cellulose esters, acrylic acid, polyester, polycarbonate etc. as polarizing filter protecting film, it is desirable forming with the film of cellulose ester more than 80%.

As cellulose esters cellulosic triacetate, cellulose iii acetate butyric ester, cellulose iii acetate, cellulose iii acetate propionic ester etc. are arranged.Wherein, degree of acetylation is that the cellulose ethanoate of 58-62.5% is desirable.When degree of acetylation less than 58% the time, then the containing ratio of moisture becomes many, size changes easily, and the degree of polarization of polarization element is reduced.

In addition, when degree of acetylation surpassed 62.5%, then the dissolubility to solvent reduced, and throughput rate descends.

In cellulose ethanoate, contain cellulosic triacetate (TAC) or cellulose diacetate (DAC).

In the polarized light diaphragm, can add and prevent aging agent.Prevent aging agent by interpolation, can prevent aging and decomposition such as cellulosic triacetate.

Prevent aging agent as described, the compound of butylamine, hindered amine compound (spy opens flat 8-325537 communique), guanidine compound (the special flat 5-271471 communique of opening), benzotriazole UV absorbing agent (spy opens flat 6-235819 communique), benzophenone UV absorbing agent (spy opens flat 6-118233 communique) etc. is arranged.

Wherein, the example as hindered amine compound has butylamine, triphenylamine, tribenzylamine etc.In addition, the derivant as guanidine has the compound shown in following formula (2a), (2b).

(2a)???????????(2b)

The addition that prevents aging agent is that 0.001-5% is desirable, and is preferably 0.01-1%.When addition less than 0.001 the time, then additive effect is few, and addition surpasses at 5% o'clock, then to improve be disadvantageous to raw materials cost.

As the tackifier of bonding polarization element polarizing filter protecting film polyethenol series tackifier, acrylic resin tackifier, epoxy being arranged is resin adhesive, isocyanate-based tackifier etc.

Fig. 1 is the phantom view of expression polarized light piece structure.

Among the figure, 1-polarization element, 2-polarizing filter protecting film.

Embodiment

The manufacture method of polarizing filter protecting film

The coating that filtration is modulated by the prescription shown in the table 1; this casting dope is made film to the mirror face stainless steel band; strip after the drying, and made in 1 hour by cellulosic triacetate (degree of acetylation: the polarizing filter protecting film of Gou Chenging 59.5%) 120 ℃ of dryings.In addition, the coating that contains methyl acetate is mixed with cellulosic triacetate and plastifier (triphen phosphate, biphenyl hexichol phosphate), and carry out heat treated after being cooled to 70 ℃, with the coating that spline filter dissolved, casting film, drying is made.

In addition, the polarizing filter protecting film that is made of Arton, polycarbonate, polyethersulfone with after the methylene chloride dissolving, is filtered, carries out casting film as diaphragm equally.

Change is with the thickness (20 μ m, 40 μ m, 80 μ m, 120 μ m) of upper film, adjusts rate of perviousness, makes embodiment 1-23 and comparative example 1-25, and embodiment and relatively be shown in table 1 and table 2.

Table 1

		Prescription 1	Prescription 2	Prescription 3	Prescription 4	Prescription 5	Prescription 6	Prescription 7	Prescription 8	Prescription 9
		Prescription 1	Prescription 2	Prescription 3	Prescription 4	Prescription 5	Prescription 6	Prescription 7	Prescription 8	Prescription 9	????TAC		??15.00	??15.00	??15.00	??15.00	??15.00	??15.00	??15.00	??15.00	??15.00
Triphenyl phosphate		???3.00	???1.50	???0.75	???2.00	???1.00	???0.50	???2.00	???1.00	???0.50	????TAC		??15.00	??15.00	??15.00	??15.00	??15.00	??15.00	??15.00	??15.00	??15.00
Triphenyl phosphate		???3.00	???1.50	???0.75	???2.00	???1.00	???0.50	???2.00	???1.00	???0.50	Biphenyl hexichol phosphate		???0.00	???0.00	???0.00	???1.00	???0.50	???0.25	???1.00	???0.50	???0.25
Methylene chloride		??75.40	??76.80	??77.50	??75.40	??76.80	??77.50	???0.00	???0.00	???0.00	Biphenyl hexichol phosphate		???0.00	???0.00	???0.00	???1.00	???0.50	???0.25	???1.00	???0.50	???0.25
Methylene chloride		??75.40	??76.80	??77.50	??75.40	??76.80	??77.50	???0.00	???0.00	???0.00	Methyl alcohol		???6.60	???6.70	???6.75	???6.60	???6.70	???6.75	???0.00	???0.00	???0.00
Ethanol		???0.00	???0.00	???0.00	???0.00	???0.00	???0.00	??12.30	??12.53	??12.64	Methyl alcohol		???6.60	???6.70	???6.75	???6.60	???6.70	???6.75	???0.00	???0.00	???0.00
Ethanol		???0.00	???0.00	???0.00	???0.00	???0.00	???0.00	??12.30	??12.53	??12.64	Normal butyl alcohol		???0.00	???0.00	???0.00	???0.00	???0.00	???0.00	???4.10	???4.18	???4.21
Methyl acetate		???0.00	???0.00	???0.00	???0.00	???0.00	???0.00	??65.60	??66.80	??67.40	Normal butyl alcohol		???0.00	???0.00	???0.00	???0.00	???0.00	???0.00	???4.10	???4.18	???4.21
Methyl acetate		???0.00	???0.00	???0.00	???0.00	???0.00	???0.00	??65.60	??66.80	??67.40	Tri-n-butylamine (to solid shape part ratio %)		???0.00	???0.00	???0.00	???0.00	???0.00	???0.00	???0.10	???0.20	???0.50
System film thickness (μ m)	???20	Comparative example 1	Comparative example 3	Comparative example 5	Comparative example 6	Comparative example 8	Comparative example 10	Comparative example 11	Comparative example 13	Comparative example 15	Tri-n-butylamine (to solid shape part ratio %)		???0.00	???0.00	???0.00	???0.00	???0.00	???0.00	???0.10	???0.20	???0.50
	???20	Comparative example 1	Comparative example 3	Comparative example 5	Comparative example 6	Comparative example 8	Comparative example 10	Comparative example 11	Comparative example 13	Comparative example 15	???40	Embodiment 1	Embodiment 3	Embodiment 5	Embodiment 8	Embodiment 10	Embodiment 12	Embodiment 15	Embodiment 17	Embodiment 19
	???80	Embodiment 2	Embodiment 4	Embodiment 6	Embodiment 9	Embodiment 11	Embodiment 13	Embodiment 16	Embodiment 18	Embodiment 20	???40	Embodiment 1	Embodiment 3	Embodiment 5	Embodiment 8	Embodiment 10	Embodiment 12	Embodiment 15	Embodiment 17	Embodiment 19
	???80	Embodiment 2	Embodiment 4	Embodiment 6	Embodiment 9	Embodiment 11	Embodiment 13	Embodiment 16	Embodiment 18	Embodiment 20	??120	Comparative example 2	Comparative example 4	Embodiment 7	Comparative example 7	Comparative example 9	Embodiment 14	Comparative example 12	Comparative example 14	Embodiment 21

Table 2

The sample film	Film thickness (μ m)
	Film thickness (μ m)				????20	????40	????80	????120
	???Arton	Embodiment 22	Comparative example 17	Comparative example 20	????20	????40	????80	????120	Comparative example 23
Polycarbonate	???Arton	Embodiment 22	Comparative example 17	Comparative example 20	Embodiment 23	Comparative example 18	Comparative example 21	Comparative example 24	Comparative example 23
Polycarbonate	Polyethersulfone	Comparative example 16	Comparative example 19	Comparative example 22	Embodiment 23	Comparative example 18	Comparative example 21	Comparative example 24	Comparative example 25

The making of polarized light piece

Iodine is adsorbed on the polyvinyl alcohol (PVA) film of extension makes polarization element, by the bonding above-mentioned polarizing filter protecting film of polyethenol series tackifier, make polarized light piece on the two sides of this polarization element.

Table 3 and table 4 illustrate the above embodiments 1-23 and comparative example 1-25 in 25 ℃, the equilibrium humidity of 60%RH and the evaluation result of polarization photosensitiveness and cementability.

Table 3

Serial number		Rate of perviousness (g/m ²24 hours)	Water percentage	The polarization photosensitiveness	Cementability
Serial number		Rate of perviousness (g/m ²24 hours)	Water percentage	The polarization photosensitiveness	Cementability	Embodiment	????1	????6.8	????0.8	????△	???○
????2	????3.8	????0.8	????○	???○			????1	????6.8	????0.8	????△	???○
????2	????3.8	????0.8	????○	???○	????3		????7.5	????0.8	????○	???○
????4	????4.2	????0.8	????○	???○	????3		????7.5	????0.8	????○	???○
????4	????4.2	????0.8	????○	???○	????5		????8.1	????0.8	????△	???○
????6	????4.5	????0.8	????○	???○	????5		????8.1	????0.8	????△	???○
????6	????4.5	????0.8	????○	???○	????7		????3.5	????1.2	????○	???○
????8	????7.2	????1.2	????△	???○	????7		????3.5	????1.2	????○	???○
????8	????7.2	????1.2	????△	???○	????9		????3.6	????1.2	????○	???○
????10	????8.2	????1.2	????○	???○	????9		????3.6	????1.2	????○	???○
????10	????8.2	????1.2	????○	???○	????11		????4.1	????1.2	????○	???○
????12	????9.1	????1.2	????△	???○	????11		????4.1	????1.2	????○	???○
????12	????9.1	????1.2	????△	???○	????13		????4.9	????1.2	????○	???○
????14	????3.3	????0.9	????○	???○	????13		????4.9	????1.2	????○	???○
????14	????3.3	????0.9	????○	???○	????15		????7.5	????0.9	????△	???○
????16	????3.8	????0.9	????○	???○	????15		????7.5	????0.9	????△	???○
????16	????3.8	????0.9	????○	???○	????17		????8.5	????0.9	????△	???○
????18	????4.2	????0.9	????○	???○	????17		????8.5	????0.9	????△	???○
????18	????4.2	????0.9	????○	???○	????19		????9.5	????0.9	????△	???○
????20	????5.6	????0.9	????○	???○	????19		????9.5	????0.9	????△	???○
????20	????5.6	????0.9	????○	???○	????21		????3.1	????0.9	????○	???○
????22	????3.1	????0.2	????○	???○	????21		????3.1	????0.9	????○	???○
????22	????3.1	????0.2	????○	???○	????23		????3.2	????0.2	????○	???○

Table 4

Serial number		Rate of perviousness (g/m ²24 hours)	Water percentage	The polarization photosensitiveness	Cementability
Serial number		Rate of perviousness (g/m ²24 hours)	Water percentage	The polarization photosensitiveness	Cementability	Comparative example	????1	????12.5	????0.8	????×	????○
????2	????2.2	????0.8	????○	????×			????1	????12.5	????0.8	????×	????○
????2	????2.2	????0.8	????○	????×	????3		????15.2	????0.8	????×	????○
????4	????2.6	????0.8	????○	????×	????3		????15.2	????0.8	????×	????○
????4	????2.6	????0.8	????○	????×	????5		????16.4	????0.8	????×	????○
????6	????13.1	????1.2	????×	????○	????5		????16.4	????0.8	????×	????○
????6	????13.1	????1.2	????×	????○	????7		????2.3	????1.2	????○	????×
????8	????16.5	????1.2	????×	????○	????7		????2.3	????1.2	????○	????×
????8	????16.5	????1.2	????×	????○	????9		????2.7	????1.2	????○	????×
????10	????18.2	????1.2	????×	????○	????9		????2.7	????1.2	????○	????×
????10	????18.2	????1.2	????×	????○	????11		????13.2	????0.9	????×	????○
????12	????2.4	????0.9	????○	????×	????11		????13.2	????0.9	????×	????○
????12	????2.4	????0.9	????○	????×	????13		????16.8	????0.9	????×	????○
????14	????2.6	????0.9	????○	????×	????13		????16.8	????0.9	????×	????○
????14	????2.6	????0.9	????○	????×	????15		????17.7	????0.9	????×	????○
????16	More than 100	????0.4	????×	????○	????15		????17.7	????0.9	????×	????○
????16	More than 100	????0.4	????×	????○	????17		????1.5	????0.2	????○	????×
????18	????1.6	????0.2	????○	????×	????17		????1.5	????0.2	????○	????×
????18	????1.6	????0.2	????○	????×	????19		More than 100	????0.4	????×	????○
????20	????0.7	????0.2	????○	????×	????19		More than 100	????0.4	????×	????○
????20	????0.7	????0.2	????○	????×	????21		????0.8	????0.2	????○	????×
????22	????95	????0.4	????×	????○	????21		????0.8	????0.2	????○	????×
????22	????95	????0.4	????×	????○	????23		????0.9	????0.2	????○	????×
????24	????1	????0.2	????○	????×	????23		????0.9	????0.2	????○	????×
????24	????1	????0.2	????○	????×	????25		????62	????0.4	????×	????○

The assay method of equilibrium humidity

With methylene chloride dissolved samples film, and carry out quantitative titration with Karl Fischer method.

The evaluation method of polarization photosensitiveness and evaluation

For polarized light piece, obtain the parallel transmitance (Yp) in the visible region, vertical transmitance (Yc) by spectrophotometer, according to following formula decision polarization luminosity P.

P = \sqrt{(Yp - Yc) / (Yp + Yc)}

In 60 ℃, the atmosphere gas of 90%RH, expose the polarized light piece sample to the open air after 500 hours, measure polarization luminosity.

Zero: polarization luminosity is more than 99.7%.

△: polarization luminosity is 99.6-99.2%.

*: polarization luminosity is less than 99.2%.

The evaluation method of connecting airtight property and evaluation

After 24 hours, shell polarizing filter protecting film at 60 ° of dry polarized light piece samples by disbonded test.

Zero: do not produce and peel off.

*: produce and peel off.

In addition, all polarized light piece samples of using the made polarizing filter protecting film of cellulosic triacetate film at 80 ℃, were exposed to the open air 500 hours in the atmosphere gas of 90%RH.Its result confirms to have the acetic acid flavor in the polarized light of the polarizing filter protecting film made of prescription 1-6 made in using with the cellulosic triacetate film.This may be owing to wearing out by hydrocellulose triacetate self in these samples and decomposing and cause.

But, in the polarized light piece that uses with the made polarizing filter protecting film of the coating of prescription 7-9, can't smell the acetic acid flavor, and also do not change in appearance.Can prove that the butylamine that adds improves the humidity resistance of cellulosic triacetate in prescription 7-9.

The present invention can prevent the aging of humidity resistance and can keep the polarized light performance well by rate of perviousness being adjusted to suitable scope, can keep the cementability of polarization element and polarized light diaphragm simultaneously well.

Claims

1. a polarizing filter protecting film is a bonding polarizing filter protecting film on the one side at least of polarization element, it is characterized in that rate of perviousness is 3-10g/m ²24 hours.

2. polarizing filter protecting film according to claim 1, at 25 ℃, the equilibrium humidity of 60%RH is 0.01-1.5%.

3. polarizing filter protecting film according to claim 1 and 2, containing hydrophobic plasticizer is 1-20%.

4. according to claim 1,2 or 3 described polarizing filter protecting films, containing the agent that prevents to wear out is 0.01-5%.

5. according to claim 1,2,3 or 4 described polarizing filter protecting films, containing cellulose esters is more than 80%.

6. polarizing filter protecting film according to claim 5, described cellulose esters are that degree of acetylation is the cellulose ethanoate of 58-62.5%.