Cross-linkable composition

Abstract

The present application relates to a cross-linkable composition. The present application can provide a cross-linkable composition without degradation of cross-linking efficiency while exhibiting conductivity by containing an ionic compound, and its use.

Claims

1. An optical laminate comprising an optical film; and a pressure-sensitive adhesive layer formed on one side of the optical film and including a cross-linked product of the cross-linkable composition, the cross-linkable composition comprising an acrylic polymer; an ionic compound having an alkali metal cation; and a compound of Formula 1 below, and having a curing rate of 30% or more according to Equation 1 below, ##STR00003## wherein, R.sub.1 to R.sub.4 are each independently a hydrogen atom or an alkyl group, curing rate=B/A×100% [Equation 1] wherein, A is a mass in g before immersing the cross-linkable composition, in which a cross-linking agent of the acrylic polymer is blended, in an amount of 1 part by weight or less relative to 100 parts by weight f the acrylic polymer, to the cross-linkable composition comprising the ionic compound in a ratio of 3 parts by weight or more relative to 100 parts by weight of the acrylic polymer, or a cross-linked product of the composition in ethyl acetate, and B is a dry mass in g of insoluble contents recovered after immersing the cross-linkable composition or the cross-linked product of the composition in ethyl acetate at room temperature for 24 hours, where the insoluble contents are components sieved by a sieve of 200 meshes, wherein the cross-linkable composition does not comprise a metal chelate cross-linking agent and a metal-containing cross-linking catalyst, in which the optical film comprising a polyvinyl alcohol polarizer, the polyvinyl alcohol polarizer comprising potassium component and zinc component, and a ratio of the potassium component to the zinc component is 0.2 to 6.

2. The optical laminate according to claim 1, wherein the acrylic polymer comprises a polymerized unit of an alkyl (meth)acrylate monomer and a polymerized unit of a carboxyl group-containing monomer.

3. The optical laminate according to claim 2, further comprising an epoxy cross-linking agent or an aziridine cross-linking agent.

4. The optical laminate according to claim 1, wherein the alkali metal cation is a lithium cation.

5. The optical laminate according to claim 1, wherein the ionic compound comprises an anion of Formula 2 below: [X(YO.sub.mR.sub.f).sub.n].sup.− [Formula 2] wherein, X is nitrogen or carbon, Y is carbon or sulfur, R.sub.f is a perfluoroalkyl group, m is 1 or 2, and n is 2 or 3.

6. The optical laminate according to claim 1, wherein the ionic compound comprises any one anion of Formulas 3 to 5 below:
[OSO.sub.2CnF.sub.2+1].sup.−  [Formula 3]
[N(SO.sub.2C.sub.nF.sub.2+1).sub.2].sup.−  [Formula 4]
[C(SO.sub.2C.sub.nF.sub.2+1).sub.3].sup.−  [Formula 5] wherein, n is a number in a range of 1 to 4.

7. The optical laminate according to claim 1, wherein the cross-linkable composition comprises the ionic compound which is in an amount of 0.001 to 20 parts by weight relative to 100 parts by weight of the acrylic polymer.

8. The optical laminate according to claim 1, wherein the cross-linkable composition comprises the ionic compound which is in an amount of 3 parts by weight or more relative to 100 parts by weight of the acrylic polymer.

9. The optical laminate according to claim 1, wherein in Formula 1, R.sub.1 and R.sub.2 are each independently an alkyl group having 1 to 4 carbon atoms, and R.sub.3 and R.sub.4 are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

10. The optical laminate according to claim 9, wherein any one of R.sub.3 and R.sub.4 is a hydrogen atom and the other is an alkyl group having 1 to 4 carbon atoms.

11. The optical laminate according to claim 1, wherein the cross-linkable composition comprises the compound of Formula 1 which is in an amount of 0.01 to 30 parts by weight relative to 100 parts by weight of the ionic compound.

12. The optical laminate according to claim 1, further comprising a cross-linking agent.

13. The optical laminate according to claim 12, wherein the cross-linking agent is an isocyanate cross-linking agent, an epoxy cross-linking agent or an aziridine cross-linking agent.

14. The optical laminate according to claim 12, wherein the cross-linkable composition comprises the cross-linking agent which is in an amount of 10 parts by weight or less relative to 100 parts by weight of the acrylic, polymer.

15. The optical laminate according to claim 12, wherein the cross-linkable composition comprises the cross-linking agent which is in an amount of 1 part by weight or less relative to 100 parts by weight of the acrylic, polymer.

16. A display device comprising a display panel to which the optical laminate of claim 1 is attached via the pressure-sensitive adhesive layer.

17. The optical laminate according to claim 2, wherein the acrylic polymer further comprises a polymerized unit of an aromatic group-containing monomer represented by the following formula 6: ##STR00004## in Formula 6, R.sub.1 represents hydrogen or an alkyl group, A represents an alkylene group, n represents an integer in a range of 0 to 3, Q represents a single bond, —O—, —S— or an alkylene group, and P represents an aryl group.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) The FIGURE is a view showing the NMR measurement results for confirming the effect of the present application.

BEST MODE

(2) Hereinafter, the present application will be specifically described by way of examples, but the scope of the present application is not limited by the following examples.

(3) 1. Measurement Method of Curing Rate

(4) The curing rate was evaluated through a gel fraction. After cross-linkable compositions prepared in Examples or Comparative Examples were each coated to an appropriate thickness, it was maintained at a temperature of about 120° C. for 3 minutes or so. Subsequently, it was again maintained at a temperature of 50° C. for 3 days to form a cross-linked layer, and then the relevant cross-linked layer was maintained in a constant temperature and humidity room (a temperature of 23° C., 50% relative humidity) for 7 days. Thereafter, about 0.2 g (=A in the gel fraction determination equation) was collected from the cross-linked layer. The collected cross-linked product was completely immersed in 50 mL of ethyl acetate and then stored in a dark room at room temperature for 1 day. Subsequently, a portion that was not dissolved in ethyl acetate (insoluble content) was collected in a #200 stainless steel wire net, which was dried at 150° C. for 30 minutes to measure the mass (dry mass of insoluble contents=B in the gel fraction measurement equation). Subsequently, the gel fraction (unit: %) was determined by substituting the measurement result into the following equation.

(5) <Gel Fraction Determination Equation>
Gel fraction=B/A×100%

(6) A: mass (0.2 g) of the pressure-sensitive adhesive

(7) B: dry mass of insoluble contents (unit: g)

(8) 2. Surface Resistance Measurement Method

(9) The surface resistance was confirmed by a probe method using a surface resistance meter from Mitsubishi. Also, the high temperature surface resistance was evaluated in the above manner after the cross-linked layer was maintained at a temperature of 80° C. for about 120 hours. Then, the moist-heat resistant surface resistance was evaluated in the above manner after the cross-linked layer was maintained at a temperature of 60° C. and 90% relative humidity for about 240 hours.

(10) 3. NMR Measurement Method

(11) NMR was confirmed by Li NMR using a Bruker 500 MHz NMR instrument.

Preparation Example 1. Preparation of Pressure-Sensitive Adhesive Polymer (A)

(12) To an 1 L reactor in which a nitrogen gas was refluxed and a cooling apparatus was installed for easy temperature control, n-butyl acrylate (n-BA) and acrylic acid (AA) were introduced in a weight ratio of 95:5 (n-BA: AA), and 100 parts by weight of ethyl acetate (EAc) was introduced thereto as a solvent. Subsequently, after the nitrogen gas was purged for 1 hour in order to remove oxygen, 0.03 parts by weight of azobisisobutyronitrile (AIBN) diluted in ethyl acetate to a concentration of 50 wt % was introduced thereto as a reaction initiator and reacted for 8 hours to prepare a copolymer (A) having a molecular weight (Mw) of about 1,800,000 or so.

Example 1

(13) An epoxy cross-linking agent (T-743L, Soken Co., Japan) was combined with the copolymer (A) of Preparation Example 1 in a ratio of about 0.037 parts by weight relative to 100 parts by weight of the solid content of the copolymer (A), LiTFSI (lithium bis(trifluoromethanesulfonylimide) as an ionic compound was combined in a ratio of about 0.74 parts by weight relative to 100 parts by weight of the solid content of the copolymer (A), and then acetylacetone was again combined in a ratio of about 0.03 parts by weight relative to 100 parts by weight of the solid content of the copolymer (A) to prepare a cross-linkable composition.

Example 2

(14) A cross-linkable composition was prepared in the same manner as in Example 1, except that the contents of the ionic compound and acetylacetone were changed to about 3.7 parts by weight and 0.03 parts by weight, respectively, relative to 100 parts by weight of the solid content of the copolymer (A).

Example 3

(15) A cross-linkable composition was prepared in the same manner as in Example 1, except that the contents of the ionic compound and acetylacetone were changed to about 3.7 parts by weight and 0.15 parts by weight, respectively, relative to 100 parts by weight of the solid content of the copolymer (A).

Comparative Example 1

(16) A cross-linkable composition was prepared in the same manner as in Example 1, except that the ionic compound and acetylacetone were not applied.

Comparative Example 2

(17) A cross-linkable composition was prepared in the same manner as in Example 1, except that acetylacetone was not combined.

Comparative Example 3

(18) A cross-linkable composition was prepared in the same manner as in Example 2, except that acetylacetone was not combined.

(19) The composition of each of the cross-linkable compositions is summarized in Table 1 below.

(20) TABLE-US-00001 TABLE 1 Epoxy cross- Ionic Copolymer linking agent compound AcAc Example 1 100 0.037  0.74  0.03 Example 2 100 0.037 3.7  0.03 Example 3 100 0.037 3.7  0.15 Comparative Example 1 100 0.037 0   0   Comparative Example 2 100 0.037  0.74 0   Comparative Example 3 100 0.037 3.7 0   Unit: part by weight Copolymer: copolymer (A) prepared in Preparation Example 1 Epoxy cross-linking agent: T-743L, Soken Co., Japan Ionic compound: LiTFSI(lithium bis(trifluoromethanesulfonyl imide)) AcAc: acetylacetone

(21) The curing rate and surface resistance value measured for each cross-linkable composition are summarized in Table 2 below.

(22) TABLE-US-00002 TABLE 2 Curing Room temperature High temperature Moisture-heat rate surface resistance surface resistance surface resistance (%) (Ω/sq) (Ω/sq) (Ω/sq) Example 1 85.3 2.64 × 10.sup.11 5.13 × 10.sup.11 1.47 × 10.sup.11 Example 2 45.5 1.08 × 10.sup.10 2.98 × 10.sup.10 7.55 × 10.sup.9  Example 3 80 9.99 × 10.sup.9  2.38 × 10.sup.10 7.15 × 10.sup.9  Comparative Example 1 81.5 Over Range Over Range 1.17 × 10.sup.12 Comparative Example 2 78.9 3.14 × 10.sup.11 6.32 × 10.sup.11 1.63 × 10.sup.11 Comparative Example 3 0 1.17 × 10.sup.10 2.57 × 10.sup.10 1.08 × 10.sup.10 Over Range: more than measurement performance of measuring equipment

(23) Review of Results

(24) As a result of measuring the curing rate of each of the cross-linkable compositions of Examples 1 to 3 and Comparative Examples 1 to 3 in the above-mentioned manner, Examples 1 to 3 were 85.3%, 45.5% and 80%, respectively, and Comparative Examples 1 to 3 were 81.5%, 78.9% and 0%, respectively.

(25) Among the results, Comparative Example 1 exhibits a high curing rate in the state that the ionic compound is not included, whereas it can be seen that when comparing with the results of Comparative Examples 2 and 3, as the addition amount of the ionic compound is increased, the curing rate is decreased. Accordingly, it can be confirmed that the ionic compound causes a decrease in the cross-linking efficiency and in particular, when a considerable amount of the ionic compound is combined as in Comparative Example 3, the cross-linking is rarely achieved.

(26) However, it can be confirmed that when the acetylacetone corresponding to the compound of Formula 1 is combined in the same composition as those of Comparative Examples 2 and 3 above (Examples 1 to 3), the curing rate is greatly increased.

(27) These results can also be verified by NMR measurement, which will be described with reference to the FIGURE as follows.

(28) In the FIGURE, the lowermost NMR result is the result measured after LiTFSI, which is an ionic compound used in Examples and Comparative Examples, is solely dissolved in a solvent of ethyl acetate, and the uppermost NMR is the result measured by combining the same epoxy cross-linking agent as applied in Examples and Comparative Examples.

(29) Comparing the two results, it can be seen that if the epoxy cross-linking agent is added to LiTFSI, the peak shifts to a down field. In the FIGURE, the second NMR from the top is the case where acetylacetone is added to a solution containing LiTFSI and the epoxy cross-linking agent so that the volume ratio thereof to the epoxy cross-linking agent is 1:0.25 (epoxy cross-linking agent: acetylacetone), and the third NMR is the result measured after being added so that the volume ratio is about 1:0.5 (epoxy cross-linking agent: acetylacetone). Through the drawing, it can be confirmed that as acetylacetone is added, the peak again shifts to an upfield. Accordingly, it can be confirmed that the phenomenon of interfering with the cross-linking reaction is solved through interaction of LiTFSI with acetylacetone.