Curable Composition

Abstract

The present application may provide a curable composition comprising a polymer component including an alkyl acrylate unit having a straight or branched alkyl group, a hydroxy group-containing monomer unit and a nitrogen-containing monomer unit, and a curing agent, and the curable composition has excellent step absorptivity, and step embedding and punching properties, and can prevent white turbidity, and is capable of implementing a low dielectric constant and improving the punching performance and handling properties. Even if such a curable composition according to the present application is applied to a stepped substrate or the like, it may prevent lifting or delayed bubbles from being generated in the step portion. In addition, the pressure-sensitive adhesive film comprising the cured product formed from the curable composition may have excellent tensile strength.

Claims

1. A curable composition comprising a polymer component and a curing agent, wherein the polymer component comprises an alkyl acrylate unit having a straight or branched alkyl group, a hydroxy group-containing monomer unit and a nitrogen-containing monomer unit, and wherein the curable composition has a punching factor in a range of 25 to 100 gf/μm before or after curing.

2. The curable composition according to claim 1, wherein the curable composition has a maximum tensile strength before or after curing in a range of greater than 250 gf and 600 gf or less.

3. The curable composition according to claim 1, wherein the curable composition has a dielectric constant at a frequency of 100 kHz before or after curing of 4.0 or less.

4. The curable composition according to claim 1, wherein the hydroxy group-containing monomer is a compound of Formula 1 below: ##STR00004## wherein, R.sub.1 is an alkylene group, and R.sub.2 is hydrogen or an alkyl group.

5. The curable composition according to claim 1, wherein the hydroxy group-containing monomer unit and the nitrogen-containing monomer unit are included in the polymer component in an amount of 8 to 20 parts by weight relative to 100 parts by weight of the alkyl acrylate unit.

6. The curable composition according to claim 5, wherein the nitrogen-containing monomer unit is included in the polymer component in an amount of 2 to 10 parts by weight relative to 100 parts by weight of the alkyl acrylate unit.

7. The curable composition according to claim 5, wherein the weight ratio of the hydroxy group-containing monomer unit to the nitrogen-containing monomer unit is in a range of 0.1 to 5.

8. The curable composition according to claim 1, wherein the nitrogen-containing monomer is one or more selected from the group consisting of (meth)acrylamide, N-alkyl (meth)acrylamide, N,N-dialkyl (meth)acrylamide, 1-aminobut-3-en-2-one, 1-(dimethylamino)but-3-en-2-one, 1-(dimethylamino)-3-methylbut-3-en-2-one, 5-aminopent-1-en-3-one, 5-(dimethylamino)pent-1-en-3-one, 5-(dimethylamino)-2-methylpent-1-en-3-one, 5-amino-2-methylpent-1-en-3-one and 5-amino-2-methylhex-1-en-3-one.

9. The curable composition according to claim 1, wherein the polymer component further comprises an alkyl methacrylate unit.

10. The curable composition according to claim 1, wherein the polymer component further comprises a unit of a compound of the following formula 2: ##STR00005## wherein, R is hydrogen or an alkyl group, and Q is a monovalent substituent having a non-aromatic ring structure with 3 to 20 carbon atoms.

11. The curable composition according to claim 1, wherein the polymer component comprises a polymers in a range of 60 to 80 wt %.

12. The curable composition according to claim 1, wherein the polymer component has a weight average molecular weight (Mw) in a range of 50,000 to 300,000.

13. The curable composition according to claim 1, wherein the curing agent comprises two or more selected from the group consisting of a polyfunctional acrylate having a molar mass of 500 g/mol or less, a polyfunctional isocyanate compound and a polyfunctional urethane acrylate.

14. The curable composition according to claim 1, wherein the curing agent is included in a range of 0.01 to 10 parts by weight relative to 100 parts by weight of the polymer component.

15. The curable composition according to claim 1, wherein the curing agent comprises a polyfunctional acrylate having a molar mass of 500 g/mol or less and a polyfunctional urethane acrylate.

16. The curable composition according to claim 15, wherein the polyfunctional urethane acrylate is included in a ratio within the range of 0.01 parts by weight to 10 parts by weight relative to 100 parts by weight of the polymer component, where the weight ratio of the polyfunctional urethane acrylate to the polyfunctional acrylate having a molar mass of 500 g/mol or less is in a range of 5 to 50.

17. The curable composition according to claim 1, further comprising a compound of the following formula 3: ##STR00006## wherein, R is hydrogen or an alkyl group, Ar.sub.1 is an arylene group, and Ar.sub.2 is an aryl group.

18. A display device comprising the curable composition of claim 1 or a cured product thereof.

19. The curable composition according to claim 1, wherein the alkyl acrylate unit is included in the polymer component in a ratio of about 50 to 95 wt %, and the hydroxy group-containing monomer unit and the nitrogen-containing monomer unit are included in the polymer component in a range of more than 8 wt % to less than 12 wt %.

20. A pressure-sensitive adhesive film comprising a base material and a cured product of the curable composition according to claim 1 formed on the base material.

Description

DESCRIPTION OF DRAWINGS

[0118] FIG. 1 is a schematic diagram illustratively showing a pressure-sensitive adhesive film of the present application.

[0119] FIG. 2 is a view showing tensile strength (force) versus tensile distance (distance) as a graph.

[0120] FIG. 3 is a schematic diagram illustratively showing a cured product of the pressure-sensitive adhesive composition.

MODE FOR INVENTION

[0121] Hereinafter, the present application will be described in detail through examples, but the scope of the present application is not limited by the following examples.

[0122] 1. Punching Factor

[0123] The punching factor (F) (unit: gf/μm) value of the pressure-sensitive adhesive composition is obtained according to the following equation 1.

F=10×(A/S)  [Equation 1]

[0124] In Equation 1, F is the punching factor (unit: gf/μm).

[0125] In Equation 1, A is the toughness value (toughness, unit: gf.Math.mm) of the cured product (pressure-sensitive adhesive) of the pressure-sensitive adhesive composition, which is measured in the following manner.

[0126] First, the pressure-sensitive adhesive is cut into the form of a film to prepare a specimen. At this time, the film-type specimen is prepared by cutting the pressure-sensitive adhesive into the form of a film having a predetermined thickness with a width of 4 cm and a length of 1 cm. The film-type specimen is fixed in a tensile tester (TA equipment (Texture analyzer plus)) so that the transverse direction becomes the tensile direction, where both ends of the specimen in the transverse direction are fixed by 1 cm. Thereafter, the specimen is tensioned at a speed of about 1,000 mm/min or so until the tensile distance becomes 200 mm. The toughness value can be obtained by integrating the graph created with the tensile strength (gf) in the tensile process as the y-axis and the tensile distance (mm) as the x-axis.

[0127] In Equation 1, S is the area of the surface (side) of the specimen in the tensile direction, and the unit is μm.Math.mm. That is, the thickness of the side of the specimen is applied as a unit of μm, and the length (1 cm) in the longitudinal direction is converted into mm, whereby the S can be obtained.

[0128] 2. Molecular Weight Evaluation

[0129] The weight average molecular weight (Mw) of the polymer component was measured using GPC (gel permeation chromatograph) under the following conditions, and the measurement results were converted using the standard polystyrene of Agilent system for manufacturing a calibration curve.

[0130] <Measurement Conditions>

[0131] Meter: Agilent GPC (Agilent 1200 series, U.S.)

[0132] Column: PLGel-M, PLGel-L series connection

[0133] Column temperature: 35° C.

[0134] Eluent: Tetrahydrofuran (THF)

[0135] Flow rate: 1.0 mL/min

[0136] Concentration: ˜1 mg/mL (100 μL injection)

[0137] 3. White Turbidity Evaluation

[0138] A glass substrate having a thickness of 1.1 mm and a glass substrate having a thickness of 0.55 mm were attached using each pressure-sensitive adhesive of Examples or Comparative Examples.

[0139] Subsequently, the laminate was left in an autoclave under conditions of 40° C. and 4 bar for 10 minutes, and then, the pressure-sensitive adhesive was irradiated with ultraviolet rays at a light quantity of 3 J using a metal halide lamp, and post-cured.

[0140] Thereafter, the pressure-sensitive adhesive attached to the glass was stored under conditions of 85° C. and 85% relative humidity for 200 hours, and left at room temperature for 1 hour, and then it was observed whether or not white spots (or white turbidity) were observed. Table 1 below is the evaluation criteria for white turbidity performance.

TABLE-US-00001 TABLE 1 Grade White turbidity ○ No abnormality X White turbidity occurrence

[0141] 4. Step Absorption Evaluation

[0142] The pressure-sensitive adhesive films of Examples or Comparative Examples were each cut to have a width of 8.0 cm and a length of 14.0 cm, thereby preparing a specimen. Thereafter, on a glass substrate having a bezel part and a screen part with a printing step of 15 μm in height, the primary lamination was performed with a pressure of 1.5 bar after one side of the release film was removed from the specimen, and after the release film on the other side of the specimen was removed, a glass substrate with a thickness of 0.55 mm was laminated thereon and the secondary lamination was performed with a pressure of 1.5 bar.

[0143] Subsequently, it was left in an autoclave under conditions of 40° C. and 4 bar for 10 minutes, and then the step absorption performance was evaluated by checking the number of bubbles generated as the step difference was not sufficiently overcome at the four vertex parts of the bezel part and the number of bubbles present in the corner parts of the bezel part. Table 2 below is the evaluation criteria for step absorption.

TABLE-US-00002 TABLE 2 Grade Vertex bubbles Corner bubbles ⊚ 1~2 Less than 10 ◯ 3~4 Less than 10 Δ 4 10 or more X 4 10 or more and line form

[0144] 5. Tensile Evaluation

[0145] The pressure-sensitive adhesive layers prepared in Examples or Comparative Examples were each laminated by 6 sheets to have a thickness of 600 μm or so, and then cut to have a width of 4.0 cm or so and a length of 1.0 cm or so, thereby preparing a specimen. Thereafter, both ends of the specimen were fixed by 1 cm in the TA equipment (Texture analyser plus) so that the transverse direction became the tensile direction, and the tensile test was performed by tensioning the specimen to 450 mm at a speed of about 1,000 mm/min. Thereafter, by evaluating the tensile strength, the tensile performance was evaluated based on the criteria shown in Table 3 according to the maximum tensile strength (unit: gf).

TABLE-US-00003 TABLE 3 Grade Maximum tensile strength ⊚ More than 550 ◯ More than 410 to 550 or less Δ More than 250 to 410 or less X 250 or less

[0146] In the above evaluation criteria, the maximum tensile strength is a tensile strength when the specimen is fractured, where the unit is gf.

[0147] 6. Dielectric Constant Evaluation

[0148] The pressure-sensitive adhesive films prepared in Examples or Comparative Examples were each cut to have a width of 2 mm and a length of 5 mm, and the pressure-sensitive adhesive layer was irradiated with ultraviolet rays at a light quantity of 3 J using a metal halide lamp and post-cured. Thereafter, the dielectric constant was measured using a dielectric constant measuring device (Agilent, E4980A LCR meter+16451B dielectric test fixture device).

Example 1

[0149] Preparation of Polymer Component

[0150] 2-ethylhexyl acrylate (EHA), 2-hydroxyethyl acrylate (HEA), 2-ethylhexyl methacrylate (EHMA), acrylamide (AAm) and isobornyl acrylate (IBoA) were introduced into a 2 L reactor in which nitrogen gas was refluxed and a cooling device was installed to facilitate temperature control in a ratio of 80:6:7:4:3 parts by weight (EHA:HEA:EHMA:AAm:IBoA) as shown in Table 4 below to form a monomer mixture. Subsequently, nitrogen gas was purged for 1 hour for removing oxygen, and AIBN (azobisisobutyronitrile) diluted to a concentration of 50 wt % in ethyl acetate was introduced thereto in an amount of about 0.03 parts by weight relative to 100 parts by weight of the monomer mixture in a state where the temperature was raised to about 67° C., and then reacted for 8 hours to prepare a syrup-type polymer component having a weight average molecular weight (Mw) of about 109,000 or so.

[0151] Preparation of Pressure-Sensitive Adhesive Composition and Pressure-Sensitive Adhesive Film

[0152] With respect to 100 parts by weight of the prepared polymer component, additional components were blended as shown in Table 5 below to prepare a curable composition (pressure-sensitive adhesive composition). Subsequently, the curable composition was applied to the release-treated surface of the release-treated release PET (poly(ethylene terephthalate)) film, and the release-treated surface of an additional release PET film was laminated on the coating layer, and then was irradiated (1 J) with ultraviolet rays by means of a metal halide lamp for 3 minutes or so to form a pressure-sensitive adhesive layer having a thickness of about 100 μm or so, thereby preparing a pressure-sensitive adhesive film. The punching factor (F) measured for the pressure-sensitive adhesive layer was 35.9 gf/μm.

Example 2

[0153] A polymer component having a weight average amount (Mw) of about 85,000 was prepared in the same method as in Example 1, except that the types and ratios of the monomers used on the preparation of the polymer component were adjusted as shown in Table 4 below, and using the same, the pressure-sensitive adhesive layer and the pressure-sensitive adhesive film were prepared in the same manner. The punching factor (F) measured for the pressure-sensitive adhesive layer was about 68.4 gf/μm or so.

Comparative Example 1

[0154] A polymer component having a weight average amount (Mw) of about 96,000 was prepared in the same method as in Example 1, except that the types and ratios of the monomers used on the preparation of the polymer component were adjusted as shown in Table 4 below, and using the same, the pressure-sensitive adhesive layer and the pressure-sensitive adhesive film were prepared in the same manner. The punching factor (F) measured for the pressure-sensitive adhesive layer was about 20.6 gf/μm or so.

Comparative Example 2

[0155] A polymer component having a weight average amount (Mw) of about 100,000 was prepared in the same method as in Example 1, except that the types and ratios of the monomers used on the preparation of the polymer component were adjusted as shown in Table 4 below, and using the same, the pressure-sensitive adhesive layer and the pressure-sensitive adhesive film were prepared in the same manner. The punching factor (F) measured for the pressure-sensitive adhesive layer was about 22.8 gf/μm or so.

Comparative Example 3

[0156] A polymer component having a weight average amount (Mw) of about 85,000 was prepared in the same method as in Example 1, except that the types and ratios of the monomers used on the preparation of the polymer component were adjusted as shown in Table 4 below, and using the same, the pressure-sensitive adhesive layer and the pressure-sensitive adhesive film were prepared in the same manner. The punching factor (F) measured for the pressure-sensitive adhesive layer was about 69.7 gf/μm or so.

Comparative Example 4

[0157] A polymer component having a weight average amount (Mw) of about 41,000 was prepared in the same method as in Example 1, except that the types and ratios of the monomers used on the preparation of the polymer component were adjusted as shown in Table 4 below, and using the same, the pressure-sensitive adhesive layer and the pressure-sensitive adhesive film were prepared in the same manner. The punching factor (F) measured for the pressure-sensitive adhesive layer was about 6.4 gf/μm or so.

Comparative Example 5

[0158] A polymer component having a weight average amount (Mw) of about 85,000 was prepared in the same method as in Example 1, except that the types and ratios of the monomers used on the preparation of the polymer component were adjusted as shown in Table 4 below, and using the same, the pressure-sensitive adhesive layer and the pressure-sensitive adhesive film were prepared in the same manner. The punching factor (F) measured for the pressure-sensitive adhesive layer was about 13.1 gf/μm or so.

Comparative Example 6

[0159] A polymer component having a weight average amount (Mw) of about 109,000 was prepared in the same method as in Example 1, except that the types and ratios of the monomers used on the preparation of the polymer component were adjusted as shown in Table 4 below, and using the same, the pressure-sensitive adhesive layer and the pressure-sensitive adhesive film were prepared in the same manner. The punching factor (F) measured for the pressure-sensitive adhesive layer was about 30.2 gf/μm or so.

TABLE-US-00004 TABLE 4 (Unit: parts by weight) EHA HEA EHMA mAAm AAm IBoA Example 1 80 6 7 — 4 3 2 80 4 7 — 6 3 Comparative 1 74 8 11 4 — 3 Example 2 70 14 9 4 — 3 3 78 6 7 — 6 3 4 78 6 7 — 6 3 5 82 6 7 — 2 3 6 80 6 7 — 4 3 *EHA: 2-Ethylhexyl acrylate *HEA: 2-Hydroxyethyl acrylate *EHMA: 2-Ethylhexyl methacrylate *mAAm: Methacrylamide *AAm: Acrylamide *IBoA : Isobornyl acrylate

TABLE-US-00005 TABLE 5 (Unit: parts by Polymer SUO- weight) component I651 BPMA 1020 HDDA KBM403 Example 1 100 0.23 0.06 0.2 0.01 0.2 2 100 0.23 0.06 0.2 0.01 0.2 Comparative 1 100 0.23 0.06 0.2 0.01 0.2 Example 2 100 0.23 0.06 0.2 0.01 0.2 3 100 0.23 0.06 0.2 0.01 0.2 4 100 0.23 0.06 0.2 0.01 0.2 5 100 0.23 0.06 0.2 0.01 0.2 6 100 0.23 0.06 0.20 — 0.2 *I651: Ciba Specialty Chemicals *BPMA: 4-Benzoylphenyl methacrylate *SUO-1020: SHIN-A T&C *HDDA: 1,6-Hexanediol diacrylate *KBM403: Shin-Etsu

[0160] The evaluation results for Examples and Comparative Examples were summarized and described in Table 6 below.

TABLE-US-00006 TABLE 6 White Step Tensile strength Dielectric constant turbidity difference (Unit: gf) (@ 100 KHz) Example 1 ◯ ⊚ ◯ (523) 3.65 2 ◯ ◯ ⊚ (751) 3.52 Comparative 1 X ◯ Δ (377) 3.81 Example 2 X X Δ (383) 4.19 3 ◯ Δ ⊚ (842) 3.46 4 ◯ ⊚ X (204) 3.60 5 Δ ◯ Δ (279) 3.47 6 ◯ ⊚ Δ (402) 3.67

[0161] As identified from the results of Tables 4 and 6, it can be seen that the curable compositions (pressure-sensitive adhesive compositions) of Examples prevent white turbidity, have excellent tensile properties and exhibit low dielectric constants, while simultaneously securing appropriate punching properties and step absorptivity, which are opposite to each other.

[0162] On the other hand, in the case of Comparative Examples 1, 2, 4 and 5, the tensile strength was lowered, so that it could be expected that the punching properties would decrease, and in Comparative Example 3, the step absorption performance was lowered.

[0163] In Comparative Example 6, the tensile properties are lowered, so that it can be expected that the punching properties will decrease.