KR102004493B1 - Ladder-like silsesquioxane polymer and resin composition for optical film comprising the same - Google Patents

Abstract

The present invention relates to a resin composition for an optical film comprising a ladder-type silsesquioxane polymer, and more particularly to a resin composition comprising a silsesquioxane polymer having a ladder structure exhibiting high compatibility with a cellulose resin, Effects and a plasticizing effect, it is useful for the production of optical films such as protective films for polarizing plates and compensation films.

Description

TECHNICAL FIELD [0001] The present invention relates to a resin composition for an optical film comprising a ladder-type silsesquioxane polymer,

The present invention relates to a resin composition for an optical film comprising a ladder-type silsesquioxane polymer, and more particularly to a resin composition for an optical film comprising a silsesquioxane polymer having a ladder structure exhibiting high compatibility with a cellulose- The present invention relates to a resin composition which is excellent in heat resistance characteristics, ultraviolet ray shielding effect, water resistance, and plasticizing effect by including an oxane polymer and can be usefully used in the production of optical films such as protective films for polarizing plates and compensation films, .

In general, cellulose-based films are widely used for optical applications such as protective films for polarizing plates because they are excellent in transparency and can easily produce films having a small anisotropy of refractive index. Particularly, it is highly utilized as an expensive compensation film through technological development such as retardation adjustment while greatly improving the contrast ratio (C / R) of a display.

However, in order to give various functions, complex technical factors are required, and the film manufacturing process needs to be diversified. However, these points lead to an increase in price, which is pointed out as a practical obstacle to various applications. As a typical example, a wide-view (WV, Japan FUJIFILM), a high-grade cellulose-based compensation film, is difficult to apply to general displays such as notebook computers due to its complexity and high price, When a general cellulose-based protective film that simply protects the polyvinyl alcohol (PVA) layer of the polarizing plate is used to replace it, there is a problem that improvement in the image quality of the display can not be expected.

The improvement of the performance of the cellulose-based film is divided into two main fields. First, after the molecular unit operation such as plasticizer and optical additive is preceded, the secondary physical properties such as elongation and cementation are controlled, . In particular, the control of optical physical properties through molecular manipulation is a key technological component of any company that studies it, and the requirements for additives that can be applied at this stage are:

1. Excellent compatibility with cellulosic resin and no haze.

2. No desorption and reactivity at high temperature and alkaline conditions.

3. Minimize degradation of properties of basic cellulose resin such as transparency, hardness and optical isotropy.

However, since the organic-monomer addition component currently used in many fields does not completely satisfy the above-mentioned conditions, the limit of performance improvement is clearly expected.

Therefore, in order to overcome the limitations of this performance, the Korean Patent Application No. 10-2009-0043088 has attempted to improve the physical properties by using the metal-based nano-dispersion, and in Korean Patent Application No. 10-2009-0132560, Benzothiazole as an additive component to improve the retardation of the film. Despite these efforts, however, the limit of compatibility and the exfoliation of molecular additive components have only been locally improved and still not completely overcome.

DISCLOSURE Technical Problem In order to solve the above problems, the present invention relates to an optical film comprising a silsesquioxane polymer having a ladder-type structure excellent in compatibility with a cellulose resin and having excellent heat resistance, ultraviolet blocking effect, water resistance, And to provide a resin composition therefor.

It is another object of the present invention to provide an optical film produced from the resin composition and having improved physical properties while maintaining excellent light transmittance of a cellulose-based film, and an optical instrument including the optical film.

In order to achieve the above object,

1) a ladder-type silsesquioxane polymer having a weight average molecular weight of 1,000 to 1,000,000; And

2) Cellulose resin

A resin composition for an optical film.

The present invention also provides an optical film made of a resin composition for an optical film and an optical apparatus including the optical film.

The resin composition for an optical film comprising a ladder-type silsesquioxane polymer and a cellulose-based resin according to the present invention comprises a ladder-type silsesquioxane polymer exhibiting high compatibility with a cellulose-based resin without any chemical reaction, , Ultraviolet ray blocking effect, water resistance and plasticizing effect, and is useful for the production of cellulose-based optical films such as protective films for polarizing plates, compensation films and the like which have improved physical properties while maintaining excellent light transmittance of cellulose-based films.

1 shows the results of comparison of the compatibility between the cellulose solution of Synthesis Example 1 and the mixed resin compositions of Examples 1 to 5 according to the present invention in terms of the transmittance (the content of the cellulose resin in the cellulose solution is 10% by weight)
Fig. 2 shows the result of comparing the compatibility of the silsesquioxane polymer with the cellulose resin with respect to the increase of the phenyl group in terms of transmittance.
FIG. 3 shows IR spectra of the cellulose-silsesquioxane mixed film according to the present invention measured using an FT-IR spectrometer.
FIG. 4 shows the thermal stability of the cellulose-silsesquioxane mixed film according to the present invention measured using a thermal gravimetric analyzer (TGA).
5 shows the results of measurement of the thermal stability of the cellulose-silsesquioxane mixed film according to the present invention using DSC.

The resin composition for an optical film of the present invention is characterized by comprising 1) a ladder-type silsesquioxane polymer having a weight average molecular weight of 1,000 to 1,000,000, and 2) a cellulose resin.

The components will be described below.

1) Silsesquioxane polymer

The silsesquioxane polymer used in the present invention is a ladder silsesquioxane polymer having a weight average molecular weight of 1,000 to 1,000,000, preferably 10,000 to 100,000.

Preferably, the ladder-type silsesquioxane polymer has a structure represented by the following Formula 1:

[Chemical Formula 1]

In Formula 1,

R ¹ to R ⁴ are each independently hydrogen, C ₁ to C ₂₀ with attached cyclic or acyclic aliphatic organic functional group, an alkyl group, an alkyl, halogen, aryl group, an amino group, a (meth) acrylic group, a vinyl group, an epoxy group or between olgi and , Wherein R ¹ to R ⁴ may be substituted with the same or different organic functional groups;

R ⁵ to R ⁸ each independently may be selected from the group consisting of a C _1-5 alkyl group, a C _3-10 cycloalkyl group, a C _6-12 aryl group, an alcohol, an alkoxy group, and combinations thereof;

n is from 1 to 100,000.

In the above, the alcohol or alkoxy group is preferably -OCR 'or -CR' = N-OH, wherein R 'is a C _1-6 alkyl group.

The ladder-type silsesquioxane polymer used in the present invention may be prepared by a known method or may be a commercially available silsesquioxane polymer. Preferably, the silsesquioxane polymer of formula (1) Can be prepared by hydrolysis of the compound of formula (2) and subsequent condensation reaction:

(2)

R ⁹ _4-m -Q _p -Si- (OR ¹⁰ ) _m

In Formula 2,

R ⁹ is an organic functional group such as hydrogen, a cyclic or acyclic aliphatic organic functional group connected with C ₁ to C ₂₀ , an alkyl group, an alkyl halide, an aryl group, an amino group, a (meth) acrylic group, a vinyl group, an epoxy group or a thiol group;

R ¹⁰ is selected from the group consisting of a C _1-5 alkyl group, a C _3-10 cycloalkyl group, a C _6-12 aryl group, an alcohol, an alkoxy group, and combinations thereof,

Q is a C _1-6 alkylene group or a C _1-6 alkyleneoxy group,

m is an integer of 0 to 4,

p is an integer of 0 or 1;

In the above, the alcohol or alkoxy group is preferably -OCR 'or -CR' = N-OH, wherein R 'is a C _1-6 alkyl group.

In the formula (2), R ⁹ or R ¹⁰ may be an aromatic organic functional group such as a phenyl group. However, when the content of aromatic organic functional groups in R ¹ to R ⁴ in the side chain group in the ladder-like silsesquioxane polymer of the present invention is too large The transmittance tends to be lowered. Therefore, it is preferable that the content of phenyl in the total 100% of the side chain groups R ¹ to R ⁴ is controlled to be less than 80 mol%. This is due to the polarity difference with the cellulose-based film due to the excessive increase of the aromatic organic functional groups.

The ladder-type silsesquioxane polymer of the present invention may be prepared by a method commonly used in the art, for example, the method described in Korean Patent Laid-Open No. 10-2010-0131904.

The condensation degree of the silsesquioxane polymer may be controlled to 1 to 99.9%, and the content of -OH at the terminal of the silsesquioxane polymer may be adjusted by varying the polarity of the cellulose resin to be mixed And preferably 0.01 to 50% of the terminal end of the silsesquioxane polymer at the end of the silsesquioxane polymer, the resin composition having excellent storage stability can be produced.

When ultraviolet absorbers conventionally known in the preparation of the compound of Formula 1 are introduced into R ¹ to R ⁸ , they may also be used as additives for imparting ultraviolet shielding properties in the production of an optical film. Specific examples of the compound that can be used as an ultraviolet absorber include (2- (5-chloro-2H-benzotriazol-2-yl) -6- (1,1- dimethylethyl) (5-chloro-2H-benzotriazole-2-yl) -6 (1,1-dimethylethyl) -4-methylphenol, octyl- (3-tert-butyl-4-hydroxy-5- (5-chloro-2H-benzotriazol- 2-yl) phenyl) -propionate ] propionate) and a UV absorber containing a halogen element such as 2- (2H-benzotriazol-2-yl) -4,6-dihydroxyphenyl- (2H-benzotriazol-2-yl) -4,6-dihydroxyphenol, 2- (2H-benzotriazol- 2- (2H-benzotriazol-2-yl) -4 (1,1,3,3-tetramethylbutyl) phenol -2-yl) -4- (1,1,3,3-tetramethylbutyl) phenol), 2- (2H-benzotriazol- - (1,1,3,3-tetramethylbutyl) phenol (2- (2H-benzotriazol-2-yl) -6- (2-hydroxy-3- (2'-ethyl) hexyl) oxy] -2-hydroxyphenyl) (2-Hydroxy-3- (2'-ethyl) hexyl) oxy] -4,5- 2-hydroxyphenyl] 4,6-bis (2,4-dimethylphenyl) -1,3,5-triazine), 2- [4- [ Hydroxyphenyl] -4,6-bis (2,4-dimethylphenyl) -1,3,5-triazine (2- [4 - [(2-Hydroxy-3-dodecyloxypropyl) oxy] -2-hydroxyphenyl ] 4,6-bis (2,4-dimethylphenyl) -1,3,5-triazine) may be used as the ultraviolet absorber.

2) Cellulose resin

The resin composition for an optical film of the present invention includes a cellulose resin. As the cellulose resin, cellulose acylate resins such as cellulose acylate, cellulose triacetate, cellulose acetate butyrate and cellulose acetate propionate may be used alone or in combination of two or more. Most preferably, Cellulose triacetate can be used. In this case, compatibility with the ladder-type silsesquioxane polymer is particularly good, and optical and physical properties such as transmittance, heat resistance and water resistance can be satisfied at the same time.

In the resin composition for an optical film of the present invention, the ladder-type silsesquioxane polymer is preferably contained in an amount of less than 0.1 to 20 parts by weight, preferably less than 15 parts by weight based on 1 part by weight of the cellulose-based resin. In this case, , Ultraviolet shielding effect, water resistance, and plasticizing effect. If the content of the silsesquioxane polymer is 20 parts by weight or more based on 1 part by weight of the cellulose resin, a polarity difference between the two materials may excessively occur, resulting in a poor commercialization and a blurring effect.

The resin composition for an optical film of the present invention may be variously used alone, but a solvent may be used for the production by a conventional method such as a commercialized solvent casting. The same effect can be expected even if any one is used.

At this time, the content of the solvent is included as the remaining amount of the resin except for the ladder-type cesium sesquioxane polymer and the cellulose-based resin, and preferably the total solid content of the ladder-type silsesquioxane polymer and the cellulose- By weight, preferably 10 to 40% by weight. When the content of the solid content is within the above range, the flatness of the film, workability and the like can be satisfactorily maintained.

In addition, the resin composition for an optical film of the present invention may further contain, if necessary, a functional additive which can be ordinarily included in a plasticizer, an ultraviolet screening agent or a resin composition for an optical film, within the usual range.

The present invention also provides an optical film produced from the resin composition for an optical film and an optical device comprising the optical film.

The optical film according to the present invention may be produced according to a method commonly used in the art, except that the resin composition for optical film is used, and the optical film according to the present invention may be produced by a spray method, a roll coater method, Coated on a substrate to a thickness of 0.1 to 5,000 μm and then hot air dried in a temperature range of 30 to 150 ° C. Since a resin composition having excellent heat resistance, ultraviolet blocking effect, water resistance and plasticizing effect is used, And is useful for producing a cellulose-based optical film such as a protective film for a polarizing plate and a compensation film, which have improved physical properties while maintaining excellent light transmittance of the film.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the scope of the present invention is not limited to the following examples.

Synthesis Example 1 : Preparation of Cellulose Solution

One part by weight of triacetyl cellulose (Sigma Aldrich, Fluka) was added dropwise to 9 parts by weight of a mixed solvent of methylene chloride and methanol mixed at a ratio of 9: 1 (weight ratio), and mixed for at least one day, to prepare a cellulose solution.

Synthesis Example 2 : Preparation of silsesquioxane polymer

A dry flask equipped with a cooling tube and a stirrer was charged with 15 wt% of distilled water, 4 wt% of methanol (purity 99.86%) and 1 wt% of tetramethylammonium hydroxide (25% in water) A reaction solvent was prepared in advance, and 80% by weight of a silane monomer was added to the mixed reaction solvent. The mixing ratio of the silane monomer was 10 mol% of trimethoxyphenylsilane (trade name: DOW CORNING (R) Z-6124 SILANE) and 10 mol% of gamma-methacryloxypropyltrimethoxysilane (DOW CORNING, (R) Z-6030 SILANE).

Thereafter, stirring was performed slowly in a nitrogen atmosphere for 8 hours, stirring of the reaction solution was stopped, and the mixture was allowed to stand at room temperature for 24 hours. Then, the reaction solution containing the precipitate was vacuum filtered to separate the precipitate. The separated precipitate was washed several times with a mixed solution of distilled water and methanol to remove impurities, finally rinsed with methanol, vacuum-dried at room temperature for 20 hours, and then 1 part by weight of the obtained product was mixed with methylene chloride and methanol at a ratio of 9: (Weight ratio) of 9 parts by weight of a mixed solvent was added dropwise to prepare a desired polyaliphatic aromatic silsesquioxane polymer resin. The polyaliphatic aromatic silsesquioxane polymer thus obtained had a weight average molecular weight of 40,000. Here, the weight average molecular weight is the polystyrene reduced average molecular weight measured by gel permeation chromatography.

Synthesis Examples 3 to 9 : Preparation of silsesquioxane polymer

Except that 80% by weight of a silane monomer was added dropwise in a molar ratio shown in Table 1 to 15% by weight of distilled water, 4% by weight of methanol (purity 99.86%) and 1% by weight of tetramethylammonium hydroxide (25% Was prepared in the same manner as in Synthesis Example 2, except that the polymer silsesquioxane resin was used.

Gamma-methacryloxypropyl
(Mole%) of trimethoxy silane Trimethoxyphenylsilane
(mole%) Synthesis Example 3 80 20 Synthesis Example 4 70 30 Synthesis Example 5 60 40 Synthesis Example 6 50 50 Synthesis Example 7 40 60 Synthesis Example 8 30 70 Synthesis Example 9 20 80

Examples 1 to 5 : Preparation of Mixed Solution of Cellulose / Silsesquioxane Resin Composition and Film Production by Solution Casting Method

The silsesquioxane polymer prepared in Synthesis Example 2 was mixed with 1 part by weight of the cellulose solution prepared in Synthesis Example 1 at 0.2, 0.4, 0.6, 0.8 and 1 part by weight, respectively, to prepare a resin composition for solution casting . The prepared composition was cast on a glass plate at a speed of 20 cm / sec to prepare a film after hot air drying.

Examples 6 to 12

Same as Example 1 except that 1 part by weight of each of the silsesquioxane polymers prepared in Synthesis Examples 3 to 9 was mixed with 1 part by weight of the cellulose solution prepared in Synthesis Example 1 to prepare respective resin compositions To prepare a film.

Comparative Example 1

The cellulose solution prepared in Synthesis Example 1 was cast on a glass plate at a speed of 20 cm / sec as in Example 1 to prepare a film after hot air drying.

Comparative Example 2

A resin composition and a film were prepared in the same manner as in Example 1, except that 20 parts by weight of the silsesquioxane polymer prepared in Synthesis Example 2 was mixed with 1 part by weight of the cellulose solution prepared in Synthesis Example 1.

Comparative Example 3

A resin was prepared in the same manner as in Synthesis Example 2, except that 80% by weight of trimethoxyphenylsilane was used as the sole silane monomer, and then a resin composition and a film were prepared in the same manner as in Examples 6 to 12.

Test Example 1

The compatibility of the silsesquioxane / cellulose resin compositions of Examples 1 to 5 and the resin compositions of Comparative Examples 1 and 2 was confirmed by checking the compatibility, the haze and the transmittance. Specifically, for compatibility testing, 10 X 10 cells used for substrate adhesion test were prepared by cross-cut method (cell area = 5 mm ² ), and the difference in cloudiness of 100 cells was measured More than 5% of the cells are excellent in compatibility when the number of cells is less than 10, excellent in less than 20 cells, less than 30 cells in average, and more than 50 cells in the cell. Further, for precise measurement of the degree of cloudiness, the degree of cloudiness at the corner portion and the center portion of all of the produced film samples was measured three times or more, and the average value thereof was described. In addition, the transmittance of the manufactured film was measured by measuring the light transmittance at 400 nm and by measuring the light absorption spectrum of the visible light by means of the edge and center measurement method in the same manner as described above. The results are shown in Table 2 and FIG.

Compatibility Cloudiness (%) Permeability (%) Comparative Example 1 - 0.4 92.0 Example 1 ◎ 0.4 92.0 Example 2 ◎ 0.6 91.5 Example 3 ◎ 0.5 91.4 Example 4 ◎ 0.7 91.0 Example 5 ○ 0.8 88.0 Comparative Example 2 × 5.1 61.0

(?: Very excellent,?: Excellent,?: Fair, X: not commercializable)

As shown in Table 2 and FIG. 1, when the transmittance of the base film prepared in Comparative Example 1 was 92%, the compositions of Examples 1 to 5 according to the present invention showed excellent compatibility. In addition, the blur effect was also remarkably excellent, less than 1%, due to the increase in compatibility.

On the other hand, in the case of the composition prepared in Comparative Example 2, it was observed that the compatibility between the two resins sharply decreased as shown in the following table. These results were found to have a proportional effect on the transmission characteristics of the manufactured film.

Test Example 2

The compatibility and transmittance of the resin compositions prepared in Examples 6-12 and Comparative Example 3 were confirmed and the results are shown in Table 3 and FIG.

Compatibility Cloudiness (%) Permeability (%) Example 6 ◎ 0.8 88.0 Example 7 ◎ 0.8 87.8 Example 8 ◎ 0.9 87.5 Example 9 ◎ One 86.5 Example 10 ○ 1.1 85.5 Example 11 ○ 1.3 84.5 Example 12 ○ 1.2 84.1 Comparative Example 3 × 5.5 67.5

As shown in Table 3 and FIG. 2, when the content of the aromatic organic functional group in the organic side chain functional group in the silsesquioxane polymer was increased over a certain level, it was observed that the haze increased sharply. Therefore, it was confirmed that the content of aromatic functional groups used to improve the physical properties should be controlled to a certain level.

Test Example 3

IR was measured using an FT-IR spectrometer (ATR mode of Perkin-Elmer system Spectrum-GX) for the cellulose-silsesquioxane mixed film prepared in Example 1. The results are shown in FIG.

As shown in Fig. 3, in the optical film according to the present invention, a broad bimodal (continuous double shape) absorption peak appeared at 960 to 1,200 cm < ^{-1 &} gt ;, indicating that the silsesquioxane chain -Si-R) and the stretching vibration of the siloxane bond in the horizontal (-Si-O-Si-) direction. Also, it was confirmed that the silsesquioxane was structurally distinct even when mixed with the cellulose - based solution, and no cloudiness characteristic was observed.

Test Example 4

The thermal stability of the cellulose-silsesquioxane mixed film prepared in Example 1 was confirmed by TGA (thermal gravimetric analyzer) and DSC, and the results are shown in FIGS. 4 and 5, respectively. At this time, TGA was measured at a scan rate of 10 DEG C / min in a temperature range of 50 to 600 DEG C under nitrogen.

As shown in FIGS. 4 and 5, it was confirmed that in the cellulose-silsesquioxane mixed film according to the present invention, the thermal properties were increased with the addition of the silsesquioxane polymer without decreasing the thermal properties of the cellulose.

Test Example 5

In order to observe the change in the moisture permeability (unit: g / m ² .day) of the cellulose-silsesquioxane polymer mixed film prepared in Example 1 and the cellulose film of Comparative Example 1, C, and 100%, respectively. The results are shown in Table 4 below.

Comparative Example 1
Cellulose film Example 1
Mixed film Primary 623 50 Secondary 650 45 Third 590 49 Fourth 660 39 Average 631 46

As shown in Table 4, the film containing the ladder-type silsesquioxane polymer according to the present invention exhibited a greatly reduced moisture permeability of about 1/14 as compared with the cellulose resin film itself.

Therefore, the film produced according to the present invention can more effectively enhance the iodine sublimation prevention function of the cellulose-based film used as a protective agent of the polarizing film.

Claims (16)

1) a ladder having a structure represented by the following general formula (1) and having a total of 100% of R ¹ to R ⁴ in the following general formula (1) having an aromatic organic functional group content (number) of less than 80% and a weight average molecular weight of 1,000 to 1,000,000; Silsesquioxane polymers; And
2) Cellulose resin
And the resin composition for an optical film.
[Chemical Formula 1]

In Formula 1,
R ¹ to R ⁴ are each independently hydrogen, C ₁ to C ₂₀ with attached cyclic or acyclic aliphatic organic functional group, an alkyl group, an alkyl, halogen, aryl group, an amino group, a (meth) acrylic group, a vinyl group, an epoxy group or between olgi and , Wherein R ¹ to R ⁴ are all substituted with the same or different organic functional groups;
R ⁵ to R ⁸ are each independently selected from the group consisting of hydrogen, a C _1-5 alkyl group, a C _3-10 cycloalkyl group, a C _6-12 aryl group, and combinations thereof;
n is from 1 to 100,000. The method according to claim 1,
Wherein the ladder-type silsesquioxane polymer is contained in an amount of 0.1 part by weight or more and less than 20 parts by weight based on 1 part by weight of the cellulose-based resin. delete The method according to claim 1,
Wherein the silsesquioxane polymer of formula (1) is prepared by hydrolyzing a compound of formula (2), followed by condensation reaction successively.
(2)
R ⁹ _4-m -Q _p -Si- (OR ¹⁰ ) _m
In this formula,
R ⁹ is hydrogen, a cyclic or acyclic aliphatic organic functional group, an alkyl group, an alkyl halide, an aryl group, an amino group, a (meth) acrylic group, a vinyl group, an epoxy group or a silyl group connected with C ₁ to C ₂₀ ;
R ¹⁰ is selected from the group consisting of hydrogen, a C _1-5 alkyl group, a C _3-10 cycloalkyl group, a C _6-12 aryl group, and combinations thereof,
Q is a C _1-6 alkylene group or a C _1-6 alkyleneoxy group,
m is an integer of 0 to 4,
p is an integer of 0 or 1; delete delete The method according to claim 1,
The resin composition for an optical film according to claim 1, wherein the content (number) of -OH at the terminal is 0.01 to 50% in the terminal group. The method according to claim 1,
Wherein at least one of R ¹ to R ⁸ further comprises an ultraviolet absorber component. The method according to claim 1,
Wherein the cellulose-based resin is at least one selected from the group consisting of cellulose acylate, cellulose triacetate, cellulose acetate butyrate and cellulose acetate propionate. The method according to claim 1,
Wherein the cellulose-based resin is cellulose triacetate. The method according to claim 1,
Wherein the resin composition further comprises a plasticizer, a functional additive or an ultraviolet screening agent. An optical film produced by applying the resin composition for an optical film according to claim 1 to a substrate and then drying. 13. The method of claim 12,
Wherein the optical film has a transmittance of at least 80%. 13. The method of claim 12,
Wherein the optical film has a moisture permeability change of 25 g / m < 2 >. 13. The method of claim 12,
Wherein the optical film is a compensation film of a display or a protective film of a polarizing plate. An optical or display device according to claim 12, characterized in that it comprises an optical film.

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