JP2003096237A - Cellulose ester film and polarizing plate-protective film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film which is excellent in transparency and stability and minimized in bleeding of plasticizers. SOLUTION: Cellulose ester films using hydrogenated petroleum resins having hydroxyl groups as the plasticizer.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a cellulose ester film, and more particularly to a cellulose ester film having excellent transparency, stability and weather resistance. The present invention also relates to a protective film for a polarizing plate, which is made by using the cellulose ester film and is remarkably excellent in transparency, stability, and weather resistance.

[0002]

2. Description of the Related Art Cellulose ester films are used in various photographic materials and optical materials because of their excellent toughness and flame retardancy. In particular, cellulose triacetate (hereinafter referred to as "TAC") is a representative support of a photographic light-sensitive material, and is also used in a liquid crystal display device whose market is expanding recently due to its optical isotropy. As a specific application in a liquid crystal display device, a protective film for a polarizing plate is typical.

Conventionally, a TAC film contains a plasticizer such as triphenyl phosphate, diethyl phthalate or ethyl phthalyl ethyl glycolate in order to improve film properties centering on mechanical properties. The use of these plasticizers does not adversely affect the flame retardancy, dimensional stability and strength properties of the TAC film, but the compatibility with TAC is insufficient, resulting in poor transparency of the obtained film. There was a problem. Further, since the compatibility is insufficient, there is a problem that the plasticizer in the film bleeds out with time and contaminates the polarizing plate.

[0004]

The object of the present invention is to provide TA
By using a plasticizer having excellent compatibility with a cellulose ester such as C, it is possible to provide a film having excellent transparency, less bleed-out of the plasticizer, and excellent stability, and further having weather resistance. Another object is to provide an excellent cellulose ester film.

[0005]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems of the prior art, the present inventors have found that a hydrogenated petroleum resin containing a hydroxyl group is used as a plasticizer for cellulose ester. It has been found that the objective can be achieved.

That is, the present invention relates to a cellulose ester film containing a plasticizer, wherein the plasticizer is a hydrogenated petroleum resin containing a hydroxyl group. The present invention also relates to a protective film for a polarizing plate, which is characterized by using the cellulose ester film.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
The hydrogenated petroleum resin containing a hydroxyl group, which is a plasticizer that is essentially used in the present invention, is not particularly limited, and hydrogenated resins obtained by hydrogenating various known hydroxyl group-containing petroleum resins can be used. In particular, alcohol-modified DCPD obtained by hydrogenating an alcohol-modified dicyclopentadiene (hereinafter, dicyclopentadiene is referred to as “DCPD”) resin containing no aromatic component from the viewpoint of good weather resistance.
Resin hydrides are preferred. The alcohol-modified DCPD resin is a resin obtained by thermally polymerizing DCPD and allyl alcohol, and specific examples thereof include Quinton 1700 (Nippon Zeon Co., Ltd.) and Neoresin NB-9.
0 (manufactured by Nippon Petrochemical Co., Ltd.) and the like are commercially available.

The hydrogenated petroleum resin containing a hydroxyl group is a known hydrogenation catalyst for a hydroxyl group-containing petroleum resin which is a raw material resin, for example, a metal catalyst such as palladium, nickel, cobalt, platinum, ruthenium, rhodium or rhenium or a metal catalyst thereof It can be obtained by hydrogenation using a metal compound such as an oxide or a sulfide. The amount of catalyst used is 100
Usually, it is preferable to set it to about 0.01 to 10 parts by weight with respect to parts by weight. When the amount of the catalyst used is 0.01 parts by weight or more, the hydrogenation time can be shortened. Further, when the amount of the catalyst used exceeds 10 parts by weight, the hydrogenation time is shortened but it is not economically preferable.

The hydrogenation reaction conditions are such that the hydrogenation pressure is usually in the range of about 0.2 to 30 MPa, and the reaction temperature is usually 80 to
It is performed in the range of about 350 ° C. The hydrogenation pressure is preferably 0.5 to 25 MPa, and the reaction temperature is 120 to 300.
℃. If the hydrogenation pressure is less than 0.2 MPa,
Alternatively, if the reaction temperature is lower than 80 ° C, hydrogenation is difficult to proceed, and if the hydrogen partial pressure exceeds 30 MPa, or if the reaction temperature exceeds 350 ° C, the resin chain is decomposed and the softening point tends to decrease. In addition, the burden on the maintenance and management of the equipment will increase.

The hydrogenation reaction is carried out in a state where the hydroxyl group-containing petroleum resin is melted or dissolved in a solvent. The solvent that dissolves the hydroxyl group-containing petroleum resin is not particularly limited, but any solvent that is inert to the hydrogenation reaction and that readily dissolves the raw materials and products may be used. For example, cyclohexane,
n-hexane, n-heptane, decalin, isopropyl alcohol, butanol, octanol, 2-ethylhexyl alcohol, tetrahydrofuran, dioxane,
Ethylene glycol, ethylene glycol dimethyl ether, ethylene glycol diethyl ether and the like can be used alone or in combination of two or more. The amount of these solvents used is not particularly limited.

The hydrogenation conditions have been described in the case of using a batch system as the reaction system, but a flow system (fixed bed system, fluidized bed system, etc.) may be used as the reaction system.

The hydroxyl group content of the hydrogenated petroleum resin containing a hydroxyl group thus obtained is determined by the hydroxyl value (JIS
(According to K0070). The hydroxyl value is not particularly limited, but is preferably about 30 to 300, more preferably 50 to 250, and 70 to 2
A value of 00 is particularly preferable.

The softening point of the hydrogenated petroleum resin containing a hydroxyl group (ring and ball method, according to JIS K2548) is not particularly limited, but is preferably about 50 to 160 ° C, more preferably about 60 to 120 ° C. Is. Also,
The number average molecular weight (polystyrene conversion value by gel permeation chromatography method) is preferably about 150 to 500.

The olefin content of the hydrogenated petroleum resin containing hydroxyl groups obtained by the above reaction is preferably 0.3% or less, and substantially 0.0% according to the above reaction. The olefin content is based on the total proton spectral area obtained by the NMR spectrum measurement of hydrogenated petroleum resin,
It can be calculated from the spectral area of protons derived from the olefin double bond observed at 5.0 to 6.5 ppm. That is, olefin content = (5.0 to 6.5 p
(sum of spectral area derived from olefin double bond observed in pm / spectral area of all protons of resin) ×
It is represented by 100 (%).

The color tone of the hydrogenated petroleum resin containing a hydroxyl group is not particularly limited, but from the viewpoint of the color tone of the cellulose ester film, it is 5 Gardner (according to JIS K5400) or less, more preferably 1 Gardner or less. According to the reaction conditions of 1), it is usually 1 Gardner or less.

Examples of the raw material cellulose ester used in the present invention include cellulose triacetate, cellulose diacetate, cellulose acetate butyrate, and cellulose acetate propionate, and cellulose triacetate is particularly preferable.

The composition ratio of the cellulose ester film according to the present invention is not particularly limited and is determined in consideration of the film performance, processability and the like according to the application. Usually, the amount of the hydroxylated hydrogenated petroleum resin used is about 1 to 40 parts by weight, preferably 10 to 30 parts by weight, and more preferably 15 to 25 parts by weight, based on 100 parts by weight of the raw material cellulose ester. When the amount of the hydroxyl group-containing hydrogenated resin used exceeds 40 parts by weight, mechanical strength and dimensional stability of the obtained cellulose ester film tend to decrease.

A plasticizer other than a hydrogenated petroleum resin containing a hydroxyl group may be added to the cellulose ester film according to the present invention without departing from the object of the present invention.
For example, phosphate ester plasticizers such as triphenyl phosphate, tricresyl phosphate, triethyl phosphate, biphenyl diphenyl phosphate, etc.,
Use phthalic acid type plasticizers such as diethyl phthalate, dimethoxyethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, etc., and other toluene sulfonamide type, triacetin, trimellitic acid ester, pyromellitic acid ester etc. alone or in combination. be able to.

The method for producing the cellulose ester film in the present invention is not particularly limited and may be a method generally used in the art. For example, US Pat. No. 2,492,9
No. 78, No. 2,739,070, No. 2,739,06
No. 9, No. 2,492,977, No. 2,336,310
No. 2,367,603, No. 2,607,704
No., British Patent Nos. 64,071, 735,892, Japanese Patent Publication Nos. 45-9074, 49-4554, 60-.
No. 27562, No. 61-39890, No. 62-420.
The method described in No. 8 and the like can be adopted.

For example, the cellulose ester film of the present invention can be easily manufactured by the following method. First, a raw material cellulose ester and a hydrogenated petroleum resin containing a hydroxyl group are dissolved with a solvent. Examples of the solvent include methanol, ethanol, n-propyl alcohol, and iso.
Lower alcohols such as -propyl alcohol and n-butanol, lower aliphatic hydrocarbon chlorides such as cyclohexanedioxane and methylene chloride can be used. The solvent composition is not particularly limited, for example, 70 to 95 parts by weight of methylene chloride,
A solvent composition in which the other solvent is 30 to 5 parts by weight is preferable. At the time of the dissolution, heating and pressurization conditions are usually adopted in order to increase the solubility and the dissolution rate and completely dissolve the raw material cellulose ester in a short time. The heating temperature at the time of dissolution is determined in consideration of the boiling point of the solvent used, and is usually 60 ° C or higher, preferably 80 to 110 ° C.
The pressure is adjusted so that the solvent does not boil at this set temperature.

The solvent dilution ratio is determined in consideration of film forming workability such as viscosity, and is usually adjusted so that the total solid content concentration of the cellulose ester and the hydroxyl group-containing hydrogenated petroleum resin is about 10 to 50% by weight. It

The cellulose ester film according to the present invention can be obtained by forming the cellulose ester solution thus obtained into a film by a conventional method.

The thickness of the cellulose ester film according to the present invention is usually 10 to 500 μm, and 40 to 10
0 μm is preferable.

If desired, additives such as a matting agent and an ultraviolet absorber may be added to the cellulose ester film of the present invention. As the matting agent, for example, fine particles of silicon oxide or the like can be added. The average particle size of the primary particles is 5 to 50 from the viewpoint of transparency of the film and matte effect.
nm is preferable, and more preferably 7 to 14 nm. From the viewpoint of maintaining transparency, the fine particles are preferably surface-treated with an organic substance. Examples of the ultraviolet absorber include benzotriazole type and benzophenone type. When the cellulose ester film of the present invention is used as a protective film member for a polarizing plate, it is particularly preferable to use a benzotriazole-based ultraviolet absorber from the viewpoint of high degree of coloration prevention in order to more effectively exhibit the performance of the polarizing plate. preferable.

The method of adding the above-mentioned plasticizer, matting agent and ultraviolet absorber is not particularly limited, but for example, these additives may be added to alcohols such as methanol and ethanol, methylene chloride, dioxolane, acetone,
It may be dissolved in an organic solvent such as methyl acetate and then added to an organic solvent solution of cellulose ester (also simply referred to as a dope), or these additives may be added directly to the dope. For those that do not dissolve in an organic solvent, a dissolver or a sand mill is used in an organic solvent and cellulose ester to disperse them and then added to the dope.

[0026]

According to the present invention, the use of a hydrogenated petroleum resin having a hydroxyl group as a plasticizer makes it possible to obtain a cellulose ester film having excellent transparency, stability and weather resistance. The film has excellent properties as a protective film for polarizing plate.

[0027]

The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these examples. In the examples, all parts are parts by weight.

Production Example 1 (Preparation of hydroxylated hydrogenated petroleum resin) Alcohol-modified DCPD resin "Quinton 1700"
(Softening point 100 ° C., hydroxyl value 217 mg KOH / g, color tone 10 Gardner, manufactured by Nippon Zeon Co., Ltd.) 100 parts and nickel / diatomaceous earth (“N-113”, JGC Chemical Co., Ltd.)
0.1 part) was charged into an autoclave and the hydrogen partial pressure was 1
The hydrogenation reaction was carried out under the conditions of 9.6 MPa, reaction temperature of 290 ° C. and reaction time of 5 hours. After the reaction was completed, the obtained resin was dissolved in 300 parts of toluene and the catalyst was removed by filtration. Then, in a separable flask equipped with a stirring blade, a reflux condenser, a thermometer, a temperature controller and a pressure indicator, the filtrate and the antioxidant (“IRGANOX 101
0 ", manufactured by Ciba Specialty Chemicals Co., Ltd.
35 parts were put, the temperature was gradually raised to 200 ° C. and 2.67 kPa and the pressure was reduced to remove the solvent, and the softening point was 75 ° C. and the hydroxyl value was 1
98 parts of an alcohol-modified DCPD resin hydride (hereinafter referred to as plasticizer a) having 60 mgKOH / g and a color tone of 300 Hazen was obtained.

Production Example 2 (Production of hydroxylated hydrogenated petroleum resin) In Production Example 1, the same operation as in Example 1 was carried out except that the reaction temperature was 270 ° C. and the nickel / diatomaceous earth was 0.5 part, thereby softening. 98 parts of an alcohol-modified DCPD resin hydride (hereinafter referred to as a plasticizer b) having a point of 85 ° C., a hydroxyl value of 100 mgKOH / g and a color tone of 300 Hazen was obtained.

Production Example 3 (Preparation of hydroxylated hydrogenated petroleum resin) The same operation as in Example 1 was carried out except that the reaction temperature was changed to 255 ° C in Production Example 1, and the softening point was 100 ° C and the hydroxyl value was 2
98 parts of an alcohol-modified DCPD resin hydride (hereinafter referred to as a plasticizer c) having 00 mgKOH / g and a color tone of 300 Hazen was obtained.

Example 1 (Preparation of Cellulose Ester Film) A cellulose ester dope solution was prepared according to the following formulation, and then a film was prepared. Cellulose triacetate 100 parts Hydrogenated petroleum resin containing hydroxyl group (plasticizer a) 15 parts Methylene chloride 475 parts Methanol 50 parts or more were charged into a closed container and completely dissolved while heating and stirring. Then, using a dice type applicator, the solution was applied onto a stainless steel substrate, the solvent was dried and removed, and then the film was peeled from the substrate to obtain a cellulose ester film sample 1 having a film thickness of 70 μm.

Examples 2 and 3 (Preparation of Cellulose Ester Film) Sample 2 was prepared in the same ratio as in Example 1 except that the hydrogenated petroleum resin containing hydroxyl groups was changed to the plasticizers b and c in Example 1.
Got 3.

Comparative Examples 1 to 3 (Preparation of Cellulose Ester Film) Samples 4 to 6 were obtained in the same ratio as in Example 1 except that the plasticizer was changed to the components shown in Table 1. .

[0034]

[Table 1]

In the table, tone H indicates Hazen color and G indicates Gardner color.

The cellulose ester film samples 1 to 6 produced as described above were subjected to various tests as described below to evaluate the performance. The evaluation results are shown in Table 2.

(Evaluation method) (1) Transparency: Five film samples are overlaid and AS
Haze was measured according to TM-D1003-52. It was judged according to the following criteria. ◯: Haze 1.0% or less Δ: Haze 1.0 to 3.0% range ×: Haze 3.0% or more (2) Stability (presence or absence of bleed-out) The produced film was 40 ° C. and 65% RH After being left inside, the film surface after one month was visually judged according to the following criteria. ◯: Almost no plasticizer bleeding and no problem at all as a product Δ: Some plasticizer bleeding can be used as a product ×: Many plasticizer bleeding cannot be used as a product (3) 10g of dope used in the production of the weather resistant film has an inner diameter of 55mm
After removing the solvent by drying, put a xenon lamp (Heraeus, "SUNSET") on the ointment can of 20.
Irradiation was continued for 0 hours, and the change in color tone was visually judged according to the following criteria. ◯: No coloring. Δ: Slightly colored. X: Remarkably colored.

[0038]

[Table 2]

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H049 BA02 BB13 BB33 BC09 BC22                 2H091 FA08X FA08Z FB02 GA16                       LA12                 4F071 AA09 AA39 AA78 AA80 AE04                       AH19 BA01 BB02 BC01 BC02                       BC10                 4J002 AB021 BA012 FD022 GP00

Claims (10)

[Claims] 1. A cellulose ester film containing a plasticizer, wherein the plasticizer is a hydrogenated petroleum resin containing a hydroxyl group. 2. The cellulose ester film according to claim 1, wherein the hydrogenated petroleum resin having a hydroxyl group is a hydride of an alcohol-modified dicyclopentadiene resin. 3. The cellulose ester film according to claim 1, wherein the hydrogenated petroleum resin having a hydroxyl group has a hydroxyl value of 30 or more and 300 or less. 4. The cellulose ester film according to claim 1, wherein the hydrogenated petroleum resin having a hydroxyl group has a number average molecular weight of 150 or more and 500 or less. 5. The cellulose ester film according to claim 1, wherein the hydrogenated petroleum resin having a hydroxyl group has a softening point of 50 ° C. or higher and 160 ° C. or lower. 6. The cellulose ester film according to claim 1, wherein the hydrogenated petroleum resin having a hydroxyl group has a color tone of 5 Gardner or less. 7. The cellulose ester film according to claim 1, wherein the hydrogenated petroleum resin having a hydroxyl group has an olefin content of 0.3% or less. 8. The cellulose ester film according to claim 1, wherein the cellulose ester is cellulose triacetate. 9. The cellulose ester film according to claim 1, wherein the hydrogenated petroleum resin containing a hydroxyl group is blended in an amount of 1 to 40 parts by weight (both in terms of solid content) with respect to 100 parts by weight of cellulose ester. . 10. A protective film for a polarizing plate, which comprises the cellulose ester film according to claim 1.