KR20160079161A - Method of manufacturing norbornene otical film - Google Patents

Abstract

The present invention relates to a method for producing a norbornene optical film. More specifically, the method comprises the following steps: producing a film by emulsifying a norbornene-based resin in a solution, wherein the norbornene-based resin is represented by chemical formula 1 and includes a recurring unit comprising an elongation improved monomer (B) and a polymerization improved monomer (M); elongating the produced film at a predetermined temperature of 140 to 250°C; and relaxing the film to a temperature (T) within a range expressed by equation 1, (extension temperature+5)(B/M)^b <= T <= (extension temperature+7)(B/M)^b. According to the present invention, a bowing phenomenon of the norbornene film is controlled, so an optical axis of a phase difference film can be controlled. In the chemical formula 1, R_1 is hydrogen, or a formyl group substituted by an alkoxy group having 1 to 2 carbons. R_2 is a formyl group substituted by an alkoxy group having 4 or more carbons, or an acetoxy methyl group. m and n are respectively integers of 1 or more. In the equation 1, the measure of the extension temperature and the T is °C. The B/M is a mole ratio of the elongation improved monomer (B) and the polymerization improved monomer (M). The b is -0.094.

Description

TECHNICAL FIELD [0001] The present invention relates to a method for manufacturing a norbornene optical film,

The present invention relates to a process for producing a norbornene optical film.

In the field of optical materials such as optical parts such as lenses, liquid crystal display elements, display substrates such as color filters and EL display element substrates, backlights, and light guide plates, inorganic glass has been generally used. However, the inorganic glass has defects such as fragility, lack of flexibility, large specific gravity, and bad workability. Thus, it is insufficient to meet the recent demand for weight reduction and miniaturization and high density, and therefore, Is strongly required.

In using a transparent resin for use in optical materials, very high performance is demanded in terms of heat resistance, chemical resistance, low water absorption, etc. in addition to transparency. For example, in manufacturing a display element substrate, it is necessary to process at a high temperature in a step of laminating a metal or a metal oxide thin film, but a large problem such as dimensional change due to deformation of the substrate due to heat or absorption of water (water absorption) is a serious problem.

Among them, the conventional cellulose based retardation film has a problem that the phase difference due to moisture changes greatly (ΔRo> 5 nm, ΔRth> 10 nm), and there is a demand for development of a film excellent in stability against moisture come.

Particularly, as the panel transportation through the open cell business becomes one trend, the optical stability (DELTA Ro <0.5 nm, DELTA Rth <0.5 nm) of the compensation film under the high temperature and high humidity environment It is highly requested.

For this reason, a cyclic olefin addition polymer and a polynorbornene have been proposed as resins that satisfy transparency, heat resistance, chemical resistance, low absorbency and optical properties, and a liquid crystal display substrate material using this polymer has been proposed (see Patent Document 1) .

The cyclic olefin addition polymer, especially polynorbornene, has a glass transition temperature as high as 250 占 폚 or higher, and therefore is a material excellent in thermal deformation resistance at high temperature processing. Furthermore, since polynorbornene has a very low hygroscopicity, it has excellent dimensional stability against changes in humidity in a use environment, and has a linear expansion coefficient as low as about 55 ppm, and thus has excellent dimensional stability against thermal fluctuations.

However, in the case of Zeonor (COP, Cyclo-Olefin Polymer), which is a representative example of the norbornene series retardation film, it has a Tg of about 150 ° C. and is formed through melt casting. The melt softening method has a disadvantage in productivity .

JP JP 05-061026 A (March 13, 1993)

Among the norbornene series retardation films, NB (modified PNB) is excellent in solubility in an organic solvent and can be formed through solution casting, which is advantageous in terms of productivity.

However, the solution casting method has a problem that a bowing phenomenon in which the film is warped may occur depending on the drying process conditions of the solvent.

Accordingly, an object of the present invention is to provide a production method capable of suppressing the Boeing phenomenon while producing a norbornene series film excellent in solubility in an organic solvent by a solution casting method.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art,

Forming a norbornene resin represented by the following formula (1) and containing a repeating unit composed of a drawability improving monomer (B) and a polymerizable monomer (M) by solution pouring;

Stretching the formed film to a predetermined temperature within a range of 140 to 250 ° C; And

And loosening the stretched film at a temperature (T) within a range expressed by the following equation (1): &lt; EMI ID = 1.0 &gt;

[Chemical Formula 1]

Wherein R ₁ is hydrogen or a formyl group substituted with alkoxy of 1 to 2 carbon atoms, R ₂ is a formyl group substituted with alkoxy having 4 or more carbon atoms, or acetoxymethyl group, m and n are each a hydrogen atom, Lt; / RTI &gt;

[Equation 1]

Here, the stretching temperature and the unit of T are ° C, B / M is the molar ratio of the extensibility improving monomer (B) to the polymerizable monomer (M), and b is -0.094.

In the present invention,

The drawability improving monomer (B) is at least one selected from the following formulas (2) to (3)

Wherein the polymerizable monomer (M) is at least one selected from the following formulas (4) to (5).

(2)

(3)

[Chemical Formula 4]

[Chemical Formula 5]

In the present invention, there is also provided a process for producing an optical film characterized in that the copolymer (B): polymerizing property improving monomer (M) = 5.5: 4.5 to 7.5: 2.5 molar copolymerization ratio.

The present invention has an effect that the bowing phenomenon of the norbornene film is suppressed and the optical axis of the retardation film can be controlled.

Hereinafter, the present invention will be described in detail.

The present invention relates to a process for producing a norbornene resin, comprising: forming a norbornene resin containing a repeating unit represented by the following formula (1) by solution pouring;

Stretching the formed film to a specific temperature within a range of 140 to 250 ° C; And

And loosening the stretched film to a temperature within a range from a specified temperature at the stretching to a temperature within the range of from the specified temperature at the stretching to the specified temperature at the stretching at +10 ° C.

[Chemical Formula 1]

Wherein R ₁ is hydrogen or a formyl group substituted with alkoxy of 1 to 2 carbon atoms, R ₂ is a formyl group substituted with alkoxy having 4 or more carbon atoms, or acetoxymethyl group, m and n are each a hydrogen atom, Lt; / RTI &gt;

The repeating unit is composed of a stretching property improving monomer (B) and a polymerizing property improving monomer (M).

As the drawability improving monomer (B), at least one selected from the following formulas (2) to (3) can be used.

(2)

(3)

[Chemical Formula 4]

[Chemical Formula 5]

The molecular weight of the norbornene resin is preferably 350,000 to 600,000 g / mol. When the molecular weight is less than 350,000 g / mol, or when the molecular weight is more than 600,000 g / mol, it may be difficult to control the process and residual solvent by increasing or decreasing the solid content.

And the copolymerization ratio is preferably 5.5: 4.5 to 7.5: 2.5: 2.5 in terms of the extensibility improving monomer (B): polymerizing property improving monomer (M). Within the above range, the film properties required in the related art can be achieved.

That is, when the film of the present invention has a Rth / Ro < 2.7 and a sample taken from a full width film is allowed to stand in a water bath for one day, the amount of retardation change is? Ro <0.5 nm,? Rth <0.5 nm, Retardation (Rth) of 200 nm or less, a retardation according to stretching of 30 nm / 10% or less, a modulus of 1300 N / nm ² or more, a photoelastic coefficient (RT) of 30 x 10 ^-12 m &lt; 2 &gt; / N or less.

Hereinafter, the present invention will be described in more detail by way of examples. It is to be understood that the following embodiments are for the purpose of illustration only and are not intended to limit the scope of the present invention.

Example

Example  One

The film was produced through recipe and process as shown below.

Process: Silica high pressure dispersion → Silica Dope Mixing → film formation (humidity 20%) → P / D (95 ℃) → stretching (stretching 185 ℃, relaxation 184.5 ℃, elongation 123.5%) → water washing → drying (70 ℃) (* 10% or less of residual solvent, substantially 0% elongation of residual solvent)

* Recipe: ANB (B: M = 6: 4) + Additive + Silica

Example  2

A film was produced in the same manner as in Example 1, except that the film was produced through the recipe and the process described below in Example 1.

* Process: film formation (humidity 20%) → P / D (95 ℃) → stretching (elongation 185 ℃, relaxation 177 ℃, elongation 127%) → water washing → drying (70 ℃) → winding , Residual solvent substantially 0% elongation)

* Recipe: ANB (B: M = 7: 3) + Additive + Silica

Comparative Example  One

A film was produced in the same manner as in Example 1, except that the film was produced through the recipe and the process described below in Example 1.

* Process: film formation (humidity 20%) → P / D (95 ° C) → stretching (elongation 185 ° C, relaxation 178 ° C, elongation 123.5%) → water washing → drying (70 ° C) , Residual solvent substantially 0% elongation)

* Recipe: ANB (B: M = 6: 4) + Additive + Silica

Comparative Example  2

A film was produced in the same manner as in Example 1, except that the film was produced through the recipe and the process described below in Example 1.

* Process: film formation (humidity 20%) → P / D (95 ° C) → stretching (elongation 185 ° C, relaxation 181 ° C, elongation 127%) → water washing → drying (70 ° C) , Residual solvent substantially 0% elongation)

* Recipe: ANB (B: M = 6: 4) + Additive + Silica

Comparative Example  3

A film was produced in the same manner as in Example 1, except that the film was produced through the recipe and the process described below in Example 1.

* Process: film formation (humidity 20%) → P / D (95 ° C) → stretching (elongation 185 ° C, relaxation 183 ° C, elongation 127%) → water washing → drying (70 ° C) , Residual solvent substantially 0% elongation)

* Recipe: ANB (B: M = 6: 4) + Additive + Silica

The results are shown in Table 1 below.

Claims (3)

Forming a norbornene resin represented by the following formula (1) and containing a repeating unit composed of a drawability improving monomer (B) and a polymerizable monomer (M) by solution pouring;
Stretching the formed film to a predetermined temperature within a range of 140 to 250 ° C; And
And loosening the stretched film to a temperature (T) within a range expressed by the following equation (1).
[Chemical Formula 1]

Wherein R ₁ is hydrogen or a formyl group substituted with alkoxy of 1 to 2 carbon atoms, R ₂ is a formyl group substituted with alkoxy having 4 or more carbon atoms, or acetoxymethyl group, m and n are each a hydrogen atom, Lt; / RTI &gt;
[Equation 1]

Here, the stretching temperature and the unit of T are ° C, B / M is the molar ratio of the extensibility improving monomer (B) to the polymerizable monomer (M), and b is -0.094. The method according to claim 1,
The drawability improving monomer (B) is at least one selected from the following formulas (2) to (3)
Wherein the polymerizable monomer (M) is at least one selected from the following formulas (4) to (5).
(2)

(3)

[Chemical Formula 4]

[Chemical Formula 5]

The process for producing an optical film according to claim 2, wherein the copolymer (B): polymerizing property improving monomer (M) = 5.5: 4.5 to 7.5: 2.5 molar copolymerization ratio.