Resin composition and reliability evaluation method thereof and color conversion film comprising the same

Abstract

The present application provides a resin composition which effectively inhibits a photobleaching phenomenon as well as realizes excellent external blocking properties and optical properties through the secondary structure transition concentration and relaxation time of the resin composition, a reliability evaluation method thereof, and a color conversion film comprising the same.

Claims

1. A resin composition comprising a polymer resin, a solvent and an organic fluorescent substance, and satisfying Equation 1 below or having a relaxation time (λ) of 20 ms or more according to Equation 2 below, wherein the polymer resin comprises (meth)acrylic acid and alkyl (meth)acrylate as a monomer, and wherein the solvent comprises dimethylformamide: $\begin{array}{cc}{C}_E\le 30\mathrm{wt}\%& \left[\mathrm{Equation}1\right]\\ \frac{D\left(t\right)}{D_1}=k\exp \left(-\frac{t}{3\lambda }\right)& \left[\mathrm{Equation}2\right]\end{array}$ in the Equation 1, when a relative viscosity of the resin composition is measured according to a plurality of concentration of the resin composition at a temperature of 25° C. and a shear rate of 10 s.sup.−1, plotting the measurement viscosities against the plurality of concentrations on a line graph, C.sub.E represents a concentration at an inflection point of the line graph, and in the Equation 2, where the resin composition is sealed between a pair of circular plates disposed coaxially and vertically at a temperature of 25° C. using an extensional viscometer and the upper plate is lifted vertically by 40 mm and held for a time of 50 ms to form a filament, D.sub.1 represents an initial diameter of the filament formed by the resin composition immediately after the upper plate of the extensional viscometer is lifted vertically by 40 mm for a time of 50 ms, D(t) represents a diameter of the filament at a breakup time (t) wherein the breakup time is the time taken from immediately after the upper plate of the extensional viscometer is lifted vertically by 40 mm to immediately before the filament is completely broken and wherein the diameter is measured at a substantial midpoint between the upper plate and the lower plate and the substantial midpoint is a point including an error range of ±5 mm at the midpoint between the upper plate and the lower plate, and k represents a proportional constant.

2. A color conversion film having a color conversion layer comprising the resin composition of claim 1.

3. The color conversion film according to claim 2, further comprising a protective film or a barrier film on at least one side of the color conversion layer.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a graph showing secondary structure transition concentrations of the resin compositions prepared in Examples and Comparative Examples of the present application, according to Equation 1.

(2) FIG. 2 is a diagram schematically showing a method of measuring a filament diameter using an extensional viscometer CaBER.

BEST MODE

(3) Hereinafter, the present invention will be described in more detail through Examples according to the present invention and Comparative Examples not according to the present invention, but the scope of the present invention is not limited by the following examples.

Example 1

(4) (1) Preparation of Resin Composition

(5) To a sealable 500 mL reaction vessel, 74.5 parts by weight of dimethylformamide (DMF, Sigma Aldrich), 0.5 part by weight of BODIPY-FL (Thermo Fisher) and 25 parts by weight of a mixture that polymethylmethacrylate and polymethacrylic acid were mixed in a weight ratio of 5:5 were introduced, and stirred at room temperature for about 1 hour to prepare a uniform resin composition.

(6) (2) Production of Color Conversion Film

(7) The resin composition prepared above was applied to the release surface of the releasing PET and dried (5 atm) in an oven at 130° C. for 3 minutes to produce a color conversion film comprising a color conversion layer having a thickness of 50 μm. For a sample that the produced film was irradiated with ultraviolet rays at 2 J/cm.sup.2 (100 mW/cm.sup.2 on the basis of A region) under a nitrogen atmosphere, physical properties were measured.

(8) (3) Measurement of Secondary Structure Transition Concentration (C.sub.E)

(9) Depending on the concentration (solid content) of the resin composition prepared in Example 1, the relative viscosity of the resin composition was measured. When the measured relative viscosities depending on the concentrations were plotted, the solid content at the inflection point of the graph gradient was measured. The viscosity was measured using a viscoelasticity meter (dynamic hybrid rheometer, DHR, TA Instruments) under a shear rate condition of 10 s.sup.−1 at 25° C., and the relative viscosity was calculated by comparing the measured viscosity with the control sample having a viscosity of 0.8 cP, and the results were shown in FIG. 1. Referring to FIG. 1, Solvent A represents dimethylformamide (DMF) used as a solvent in Example 1.

Example 2

(10) (1) Preparation of Resin Composition

(11) To a sealable 500 mL reaction vessel, 74.5 parts by weight of dimethylformamide (DMF, Sigma Aldrich), 0.5 part by weight of BODIPY-FL (Thermo Fisher) and 25 parts by weight of a mixture that polymethylmethacrylate and polymethacrylic acid were mixed in a weight ratio of 5:5 were introduced, and stirred at room temperature for about 1 hour to prepare a uniform resin composition.

(12) (2) Production of Color Conversion Film

(13) The resin composition prepared above was applied to the release surface of the releasing PET and dried (5 atm) in an oven at 130° C. for 3 minutes to produce a color conversion film comprising a color conversion layer having a thickness of 50 μm. For a sample that the produced film was irradiated with ultraviolet rays at 2 J/cm.sup.2 (100 mW/cm.sup.2 on the basis of A region) under a nitrogen atmosphere, physical properties were measured.

(14) (3) Relaxation Time (λ) Measurement

(15) As shown in FIG. 2, for the resin composition solution prepared in Example 2, the relaxation time was measured using an extensional viscometer CaBER. The resin composition was sealed between a pair of circular plates disposed coaxially and vertically at a temperature of 25° C. The diameter of the filament formed by the resin composition was measured in real time using a laser micrometer in a state where the upper plate was lifted vertically by 40 mm for a time of 50 ms and held as it was. When the results were shown as a graph of diameter change with time, the gradient at the breakup time was measured and the relaxation time (λ) was measured according to the above-described Equation 2. The relaxation time was calculated using an MATLAB program.

Comparative Example 1

(16) A resin composition and a color conversion film were produced in the same manner as in Example 1, except that propylene glycol methyl ethyl acetate (PGME) was used instead of dimethyl formamide (DMF).

(17) For the resin composition, the secondary structure transition concentration (C.sub.E) was measured as in Example 1, and the results were shown in FIG. 1. Referring to FIG. 1, Solvent B represents propylene glycol methyl ethyl acetate (PGME) used as a solvent in Comparative Example 1.

Comparative Example 2

(18) A resin composition and a color conversion film were produced in the same manner as in Example 1, except that tetrahydrofuran (THF) was used instead of dimethylformamide (DMF).

(19) For the resin composition, the secondary structure transition concentration (C.sub.E) was measured as in Example 1.

Comparative Example 3

(20) A resin composition and a color conversion film were produced in the same manner as in Example 1, except that propylene glycol methyl ethyl acetate (PGME) was used instead of dimethyl formamide (DMF).

(21) For the resin composition, the relaxation time (λ) was measured as in Example 2.

Comparative Example 4

(22) A resin composition and a color conversion film were produced in the same manner as in Example 1, except that tetrahydrofuran (THF) was used instead of dimethylformamide (DMF).

(23) For the resin composition, the relaxation time (λ) was measured as in Example 2.

(24) The measurement results were summarized and described in Tables 1 and 2 below.

(25) TABLE-US-00001 TABLE 1 Comparative Example Example 1 1 2 Secondary structure 20 wt % >30 wt % >30 wt % transition concentration (C.sub.E)

(26) TABLE-US-00002 TABLE 2 Comparative Example Example 2 3 4 Relaxation time (λ) 27 ms 17 ms 14 ms

(27) In Examples and Comparative Examples above, when the polymer resins were polymethylmethacrylate and polymethacrylic acid, it was evaluated whether Equation 1 or 2 was satisfied as the solvent type was changed, whereby the solvent suitable for the specific polymer resin could be selected.

(28) As to the light resistance evaluation of the color conversion films produced in Examples and Comparative Examples, as the secondary structure transition concentration (C.sub.E) of the resin composition was lower and the relaxation time was longer, excellent light resistance was shown.