Polymer composition

Abstract

The present invention relates to a polymer composition, an optical laminate and a display device, and can provide a polymer composition capable of forming a pressure-sensitive adhesive layer which has excellent workability, durability and dimensional stability and is capable of effectively alleviating the bending phenomenon of the display, through a polymer capable of forming a physically cross-linked structure together with a chemically cross-linked structure. In addition, the present invention can provide an optical laminate comprising a cross-linked product of the polymer composition and a display device comprising the same.

Claims

1. A polymer composition comprising a block copolymer comprising a first block having a glass transition temperature of 20° C. or higher and being in a form of a triblock copolymer, and a second block having a glass transition temperature of 10° C. or lower, wherein the second block comprises a cross-linkable functional group, wherein the first block comprises A blocks having a glass transition temperature of 30° C. or higher and a B block having a glass transition temperature of 0° C. or lower, wherein the A blocks are bonded to both ends of the B block, respectively, and wherein the second block is bonded to the ends of the A blocks.

2. The polymer composition according to claim 1, wherein each of the A blocks comprises, as a main component, a polymerized unit derived from at least one selected from the group consisting of alkyl methacrylate, acrylamide, N-alkyl acrylamide, styrene, a styrene derivative, maleimide and acrylonitrile.

3. The polymer composition according to claim 1, wherein the B block comprises, as a main component, a polymerized unit derived from at least one selected from the group consisting of alkyl acrylate, an olefin compound, a diene compound and an alkylene oxide.

4. The polymer composition according to claim 1, wherein the A blocks have a weight ratio in a range of 50 to 95 wt % based on the total weight of the A and B blocks.

5. The polymer composition according to claim 1, wherein the first block has a number average molecular weight in a range of from 15,000 to 150,000.

6. The polymer composition according to claim 1, wherein the first block has a polydispersity index (Mw/Mn) in a range of 1.01 to 3.

7. The polymer composition according to claim 1, wherein the second block comprises, as a main component, a polymerized unit derived from alkyl acrylate.

8. The polymer composition according to claim 1, wherein the second block further comprises a polymerized unit derived from 0.1 to 5 parts by weight of a cross-linkable monomer relative to 100 parts by weight of alkyl acrylate.

9. The polymer composition according to claim 1, wherein the second block has a weight ratio in a range of 65 to 95 wt % based on the total weight of the first and second blocks.

10. The polymer composition according to claim 1, wherein the block copolymer has a number average molecular weight (Mn) in a range of 100,000 to 800,000.

11. The polymer composition according to claim 1, wherein the block copolymer has a polydispersity index (Mw/Mn) of 5 or less.

12. The polymer composition according to claim 1, wherein the block copolymer forms a phase separated structure.

13. The polymer composition according to claim 12, wherein the phase separated structure is a spherical structure.

14. The polymer composition according to claim 1, further comprising a multifunctional cross-linking agent having a functional group reactive with the cross-linkable functional group.

15. The polymer composition according to claim 1, wherein the first block does not comprise a cross-linkable functional group.

16. An optical laminate comprising an optical film; and a pressure-sensitive adhesive layer formed on one side of said optical film, wherein said pressure-sensitive adhesive layer comprises a cross-linked product of the polymer composition of claim 1.

17. A pressure-sensitive adhesive optical film in which a pressure-sensitive adhesive layer is provided on an optical film through a primer layer, characterized in that the pressure-sensitive adhesive layer is formed by a pressure-sensitive adhesive containing the polymer composition according to claim 1.

18. A display device comprising the optical laminate of claim 16.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a diagram showing a structure of an exemplary pressure-sensitive adhesive optical film of the present invention.

MODE FOR INVENTION

(2) Hereinafter, the present invention will be described in more detail through the examples according to the present invention and comparative examples not complying with the present invention, but the scope of the present invention is not limited by the following examples.

(3) In the following examples, Mw means a weight average molecular weight, and Mn means a number average molecular weight.

(4) 1. Molecular Weight Measurement

(5) The number average molecular weight (Mn) and the molecular weight distribution (PDI) were measured using GPC (gel permeation chromatography) under the following conditions, and for producing a calibration curve, the measurement results were converted using standard polystyrene of Agilent system.

(6) <Measuring Conditions>

(7) Measuring instrument: Agilent GPC (Agilent 1200 series, U.S.)

(8) Column: Two PL Mixed B connected

(9) Column temperature: 40° C.

(10) Eluent: THF (tetrahydrofuran)

(11) Flow rate: 1.0 mL/min

(12) Concentration: ˜1 mg/mL (100 μl injection)

(13) 2. Durability Evaluation Method

(14) The pressure-sensitive adhesive polarizing plate produced in Examples or Comparative Examples was tailored to have a width of 320 cm and a height of 180 cm to prepare a specimen. The prepared specimen is attached to a commercially available LCD panel having a thickness of about 0.7 mm via a pressure-sensitive adhesive layer, and the panel with the attached specimen is stored at 50° C. and 5 atm for about 20 minutes to prepare a sample. After the prepared sample is maintained at 80° C. for 300 hours, the durability is evaluated according to the following criteria by observing whether or not bubbles or peeling phenomena occur at the pressure-sensitive adhesive interface of the pressure-sensitive adhesive layer.

(15) <Evaluation Criteria for Durability>

(16) A: When the occurrence of bubbles and peeling phenomena are not observed

(17) B: When bubbles and/or peeling phenomena are slightly observed

(18) C: When a large amount of bubbles and/or peeling phenomena are observed

(19) 3. Evaluation Method of Bending Suppression Force

(20) The pressure-sensitive adhesive polarizing plate produced in Examples or Comparative Examples is tailored to have a width of 3 cm and a height of 40.5 cm to prepare a specimen. The prepared specimen is attached to a panel for LCD having a thickness of about 0.7 mm, and a width of 4 cm and a height of 42 cm via a pressure-sensitive adhesive layer. One end of the specimen is attached to an oven wall with an iron plate support using a magnet, and the distance that the other end is spaced from the wall is measured (d1). After storing the specimen at 60° C. for 72 hours, the bending is measured by measuring the distance (d2) spaced from the oven wall. A relative fraction of bending is calculated based on the bending value of the specimen using the random copolymer of Comparative Example 3.
Bending=d2−d1
Relative bending fraction (%)=(bending of a specimen/bending of the reference specimen)×100

Preparation Example 1. Preparation Example of Pentablock Copolymer (A1)

(21) 0.5 g of ethylene bis(2-bromoisobutyrate), 15.5 g of butyl acrylate (BA) and 16 g of ethyl acetate were placed in a 500 mL round-bottom flask and sealed, and then the nitrogen bubbling was performed for about 40 minutes to remove oxygen. After removing oxygen, the flask was placed in an oil bath heated to 65° C. and a solution containing 0.002 g of CuBr.sub.2 and 0.006 g of TPMA (tris(2-pyridylmethyl)amine) dissolved in 0.1 mL of deoxygenated DMF (N,N-dimethylformamide) was introduced into the flask. Subsequently, the reaction was initiated by introducing 0.04 g of Sn(EH).sub.2 (tin (II) 2-ethylhexanoate) as a catalyst reducing agent thereto. At the point that a monomer conversion reached about 90%, 140 g of methyl methacrylate (MMA) and 140 g of ethyl acetate, in which oxygen was removed in advance, were introduced, and the nitrogen bubbling was additionally performed for 40 minutes to remove oxygen. When the temperature of the reactant reached 65° C., a solution containing 0.025 g of CuBr.sub.2 and 0.064 g of TPMA (tris(2-pyridylmethyl)amine) dissolved in 1.0 mL of deoxygenated DMF (N,N-dimethylformamide) was introduced thereto and 0.49 g of Sn(EH).sub.2 (tin (II) 2-ethylhexanoate) was placed therein to perform a chain extension reaction. When the conversion reached 80% or more, the reaction was terminated, and a macroinitiator having a number average molecular weight (Mn) of 85,000 and a molecular weight distribution (Mw/Mn) of 1.32 was prepared. 100 g of the macroinitiator, obtained by precipitating the reaction mixture from methanol followed by vacuum drying, 840 g of butyl acrylate (BA), 8.5 g of 4-hydroxybutyl acrylate (4-HBA) and 1000 g of ethyl acetate were charged into a 3 L polymerization reactor and nitrogen was bubbled for about 60 minutes to remove oxygen. A catalyst solution prepared by mixing 0.047 g of CuBr.sub.2, 0.12 g of TPMA (tris(2-pyridylmethyl)amine) and 5 mL of DMF (N,N-dimethylformamide), in a condition that the reaction temperature was maintained at 65° C. under a nitrogen atmosphere, was introduced thereto and 1.23 g of Sn(EH).sub.2 (tin (II) 2-ethylhexanoate) was introduced thereto to initiate the reaction. At the point that the reaction conversion reached about 70%, the reaction was terminated to produce a block copolymer solution having a molecular weight (Mn) of 350,000 and a molecular weight distribution (Mw/Mn) of 1.84. Here, the weight ratio of the first block and the second block is 14:86 or so.

Preparation Example 2. Preparation Example of Pentablock Copolymer (A2)

(22) 0.26 g of ethylene bis(2-bromoisobutyrate), 28.2 g of butyl acrylate (BA) and 30 g of ethyl acetate were placed in a 500 mL round-bottom flask and sealed, and then the nitrogen bubbling was performed for about 40 minutes to remove oxygen. After removing oxygen, the flask was placed in an oil bath heated to 65° C. and a solution containing 0.005 g of CuBr.sub.2 and 0.013 g of TPMA (tris(2-pyridylmethyl)amine) dissolved in 0.2 mL of deoxygenated DMF (N,N-dimethylformamide) was introduced into the flask. Subsequently, the reaction was initiated by introducing 0.72 g of a solution containing 5 wt % of azobisisobutyronitrile (AIBN) as a catalyst reducing agent and ethyl acetate as a solvent thereto. At the point that a monomer conversion was about 90%, 145 g of methyl methacrylate (MMA), 14.5 g of styrene and 160 g of ethyl acetate, in which oxygen was removed in advance, were introduced, and the nitrogen bubbling was additionally performed for 40 minutes to remove oxygen. When the temperature of the reactant reached 65° C., a solution containing 0.036 g of CuBr.sub.2 and 0.092 g of TPMA (tris(2-pyridylmethyl)amine) dissolved in 1.0 mL of deoxygenated DMF (N,N-dimethylformamide) was introduced thereto and 0.6 g of a solution containing 5 wt % of azobisisobutyronitrile (AIBN) as a catalyst reducing agent and ethyl acetate as a solvent was introduced thereto to perform a chain extension reaction. When the conversion reached 80%, all the reaction mixture was transferred to a 3 L polymerization reactor through a pump. 1300 g of butyl acrylate, 13.1 g of 4-hydroxybutyl acrylate (4-HBA) and 1000 g of ethyl acetate were charged into the 3 L polymerization reactor and nitrogen was bubbled for about 60 minutes to remove oxygen. A catalyst solution prepared by mixing 0.035 g of CuBr.sub.2, 0.090 g of TPMA (tris(2-pyridylmethyl)amine) and 5 mL of DMF (N,N-dimethylformamide), in a condition that the reaction temperature was maintained at 65° C. under a nitrogen atmosphere, was introduced thereto and 3.3 g of the solution containing 5 wt % of azobisisobutyronitrile (AIBN) and ethyl acetate as a solvent was introduced thereto to initiate the chain extension reaction. At the point that the reaction conversion reached about 80%, the reaction was terminated to produce a block copolymer solution having a molecular weight (Mn) of 250,000 and a molecular weight distribution (Mw/Mn) of 2.88. Here, the weight ratio of the first block and the second block is 15:85 or so.

Preparation Example 3. Preparation of Pentablock Copolymer (A3)

(23) 19.5 g of polyethylene glycol bis(2-bromoisobutyrate) (number average molecular weight, Mn, 10,000), 150 g of methyl methacrylate (MMA) and 170 g of ethyl acetate were placed in a 500 mL round-bottom flask, and the nitrogen bubbling was performed for 40 minutes to remove oxygen. The flask was placed in an oil bath heated to 65° C., and when the temperature of the reactant reached 65° C., a solution, in which 0.033 g of CuBr.sub.2 and 0.085 g of TPMA (tris(2-pyridylmethyl)amine) were dissolved in 1.5 mL of deoxygenated DMF (N,N-dimethylformamide) was introduced thereto and 5.3 g of a solution containing 5 wt % of azobisisobutyronitrile (AIBN) and ethyl acetate as a solvent was introduced thereto to perform a chain extension reaction. When the conversion reached 80%, all the reaction mixture was transferred to a 3 L polymerization reactor through a pump. 1320 g of butyl acrylate (BA), 13.3 g of 4-hydroxybutyl acrylate (4-HBA) and 1000 g of ethyl acetate were charged into the 3 L polymerization reactor and nitrogen was bubbled for about 60 minutes to remove oxygen. A catalyst solution prepared by mixing 0.039 g of CuBr.sub.2, 0.10 g of TPMA (tris(2-pyridylmethyl)amine) and 5 mL of DMF (N,N-dimethylformamide), in a condition that the reaction temperature was maintained at 65° C. under a nitrogen atmosphere, was introduced thereto and 3.3 g of the solution containing 5 wt % of azobisisobutyronitrile (AIBN) and ethyl acetate as a solvent was introduced thereto to initiate the chain extension reaction. At the point that the reaction conversion reached about 85%, the reaction was terminated to produce a block copolymer solution having a molecular weight (Mn) of 240,000 and a molecular weight distribution (Mw/Mn) of 3.15. Here, the weight ratio of the first block and the second block is 13:87 or so.

Preparation Example 4. Preparation of Pentablock Copolymer (A4)

(24) 0.33 g of ethylene glycol di-alphabromoisobutyrate, 22.9 g of 3-ethylhexyl acrylate (2-EHA) and 25 g of ethyl acetate were placed in a 500 mL round-bottom flask and sealed, and then the nitrogen bubbling was performed for about 40 minutes to remove oxygen. After removing oxygen, the flask was placed in an oil bath heated to 65° C. and a solution, in which 0.003 g of CuBr.sub.2 and 0.007 g of TPMA (tris(2-pyridylmethyl)amine) were dissolved in 0.2 mL of deoxygenated DMF (N,N-dimethylformamide) was introduced into the flask. Subsequently, the reaction was initiated by introducing 0.40 g of a 5% EA solution of azobisisobutyronitrile (AIBN) as a catalyst reducing agent thereto. At the point that a monomer conversion was about 90%, 130 g of methyl methacrylate (MMA) and 160 g of ethyl acetate, in which oxygen was removed in advance, were introduced, and the nitrogen bubbling was additionally performed for 40 minutes to remove oxygen. When the temperature of the reactant reached 65° C., a solution, in which 0.029 g of CuBr.sub.2 and 0.075 g of TPMA (tris(2-pyridylmethyl)amine) were dissolved in 1.0 mL of DMF (N,N-dimethylformamide) removing oxygen, was introduced thereto and 4.6 g of a solution containing 5 wt % of azobisisobutyronitrile (AIBN) and ethyl acetate as a solvent was introduced thereto to perform a chain extension reaction. When the conversion reached 80%, all the reaction mixture was transferred to a 3 L polymerization reactor through a pump. 1185 g of butyl acrylate (BA), 12.0 g of 4-hydroxybutyl acrylate (4-HBA) and 1000 g of ethyl acetate were charged into the 3 L polymerization reactor and nitrogen was bubbled for about 60 minutes to remove oxygen. A catalyst solution prepared by mixing 0.036 g of CuBr.sub.2, 0.093 g of TPMA (tris(2-pyridylmethyl)amine) and 5 mL of DMF (N,N-dimethylformamide), in a condition that the reaction temperature was maintained at 65° C. under a nitrogen atmosphere, was introduced thereto and 3.0 g of the solution containing 5 wt % of azobisisobutyronitrile (AIBN) and ethyl acetate as a solvent was introduced thereto to initiate the chain extension reaction. At the point that the reaction conversion reached about 70%, the reaction was terminated to produce a block copolymer solution having a molecular weight (Mn) of 220,000 and a molecular weight distribution (Mw/Mn) of 2.85. Here, the weight ratio of the first block and the second block is 15:85 or so.

(25) The compositions and physical properties of the block copolymers prepared in Preparation Examples 1 to 4 are summarized in the following table.

(26) TABLE-US-00001 TABLE 1 Preparation Example 1 2 3 4 A1 A2 A3 A4 Block First Composition of A block MMA MMA + St MMA MMA copolymer block Composition of B Block BA BA PEG EHA (A-B-A) Tg of A block 105° C. 103° C. 105° C. 105° C. Tg of B block −54° C. −54° C. −85° C. −50° C. Tg of the first block  77° C.  62° C.  59° C.  58° C. A:B weight ratio 11:89 18:82 14:86 17:83 Mn 85000 70000 76000 65000 Dispersity (Mw/Mn) 1.32 1.75 1.58 1.62 Second Composition BA + HBA BA + HBA BA + HBA BA + HBA block Tg −54° C. −54° C. −54° C. −54° C. First block second block weight ratio 14:86 15:85 13:87 15:85 Mn 350000 250000 240000 220000 Dispersity (Mw/Mn) 1.84 2.88 3.15 2.85 MMA: methyl methacrylate St: styrene BA: butyl acrylate PEG: polyethylene glycol EHA: 2-ethylhexyl acrylate HBA: 4-hydroxbutyl acrylate

Comparative Preparation Example 1. Preparation of Triblock Copolymer (B1)

(27) 0.26 g of ethylene glycol di-alphabromoisobutyrate, 190 g of methyl methacrylate (MMA) and 190 g of ethyl acetate were introduced, and the nitrogen bubbling was performed for 40 minutes to remove oxygen. When the temperature of the reactant reached 65° C., a solution, in which 0.036 g of CuBr.sub.2 and 0.092 g of TPMA (tris(2-pyridylmethyl)amine) were dissolved in 1.5 mL of deoxygenated DMF (N,N-dimethylformamide) was introduced thereto and 6 g of a solution containing 5 wt % of azobisisobutyronitrile (AIBN) and ethyl acetate as a solvent was introduced thereto to perform a chain extension reaction. When the conversion reached 80%, all the reaction mixture was transferred to a 3 L polymerization reactor through a pump. 1300 g of butyl acrylate (BA), 13.1 g of 4-hydroxybutyl acrylate (4-HBA) and 1000 g of ethyl acetate were charged into the 3 L polymerization reactor and nitrogen was bubbled for about 60 minutes to remove oxygen. A catalyst solution prepared by mixing 0.035 g of CuBr.sub.2, 0.090 g of TPMA (tris(2-pyridylmethyl)amine) and 5 mL of DMF (N,N-dimethylformamide), in a condition that the reaction temperature was maintained at 65° C. under a nitrogen atmosphere, was introduced thereto and 3.3 g of the solution containing 5 wt % of azobisisobutyronitrile (AIBN) and ethyl acetate as a solvent was introduced thereto to initiate the chain extension reaction. At the point that the reaction conversion reached about 80%, the reaction was terminated to produce a block copolymer solution having a molecular weight (Mn) of 240,000 and a molecular weight distribution (Mw/Mn) of 2.84. Here, the weight ratio of the first block and the second block is 15:85 or so.

Comparative Preparation Example 2. Preparation of Diblock Copolymer (B2)

(28) 0.28 g of ethyl alphabromoisobutyrate, 190 g of methyl methacrylate (MMA) and 190 g of ethyl acetate were introduced, and the nitrogen bubbling was performed for 40 minutes to remove oxygen. When the temperature of the reactant reached 65° C., a solution, in which 0.036 g of CuBr.sub.2 and 0.092 g of TPMA (tris(2-pyridylmethyl)amine) were dissolved in 1.5 mL of deoxygenated DMF (N,N-dimethylformamide) was introduced thereto and 6 g of a solution containing 5 wt % of azobisisobutyronitrile (AIBN) and ethyl acetate as a solvent was introduced thereto to perform a chain extension reaction. When the conversion reached 80%, all the reaction mixture was transferred to a 3 L polymerization reactor through a pump. 1300 g of butyl acrylate (BA), 13.1 g of 4-hydroxybutyl acrylate (4-HBA) and 1000 g of ethyl acetate were charged into the 3 L polymerization reactor and nitrogen was bubbled for about 60 minutes to remove oxygen. A catalyst solution prepared by mixing 0.035 g of CuBr.sub.2, 0.090 g of TPMA (tris(2-pyridylmethyl)amine) and 5 mL of DMF (N,N-dimethylformamide), in a condition that the reaction temperature was maintained at 65° C. under a nitrogen atmosphere, was introduced thereto and 3.3 g of the solution containing 5 wt % of azobisisobutyronitrile (AIBN) and ethyl acetate as a solvent was introduced thereto to initiate the chain extension reaction. At the point that the reaction conversion reached about 80%, the reaction was terminated to produce a block copolymer solution having a molecular weight (Mn) of 260,000 and a molecular weight distribution (Mw/Mn) of 2.87. Here, the weight ratio of the first block and the second block is 15:85 or so.

Comparative Preparation Example 3. Preparation of Random Copolymer (B3)

(29) The random copolymer B3 into which only chemical cross-linking was introduced was prepared as follows. 200 g of butyl acrylate (BA), 2.0 g of 4-hydroxybutyl acrylate (4-HBA) and 600 g of ethyl acetate were charged into a flask and then nitrogen was bubbled for 60 minutes to remove dissolved oxygen. When the reaction temperature reached 65° C., a 2 wt % ethyl acetate solution containing 0.10 g of azobisisobutyronitrile (AIBN) was introduced to initiate the reaction. When the reaction conversion ratio reached about 70%, the reaction was terminated to obtain a random copolymer having a molecular weight (Mn) of 220,000 and a molecular weight distribution of 4.52.

Example 1

(30) To 100 parts by weight of the pentablock copolymer (A1) prepared in Preparation Example 1, about 0.2 parts by weight of a cross-linking agent (TDI-TMPTA adduct, toluene diisocyanate-trimethylolpropane adduct) and about 0.02 parts by weight of a known cross-linking catalyst were blended to prepare a polymer composition. Subsequently, the composition was coated on a release-treated PET (poly(ethylene terephthalate)) film to a thickness of about 25 μm and dried at 120° C. for about 3 minutes. Subsequently, the dried layer thus formed was transferred to one side of a known polarizing plate to produce a pressure-sensitive adhesive applied polarizing plate.

Examples 2 to 4

(31) A pressure-sensitive adhesive polarizing plate was prepared in the same manner as in Example 1, except that the pentablock copolymers (A2, A3, A4) prepared in Preparation Examples 2 to 4 were used.

Comparative Examples 1 to 3

(32) A pressure-sensitive adhesive polarizing plate was produced in the same manner as in Example 1, except that the block copolymers (B1, B2) and the random copolymer prepared in Comparative Preparation Examples 1 to 3 were used.

(33) The results of evaluating the physical properties of the polymer compositions of Examples and Comparative Examples, and the like were summarized and described in Table 2 below.

(34) TABLE-US-00002 TABLE 2 Comparative Example B3 Example (reference A1 A2 A3 A4 B1 B2 specimen) Polymer pentablock pentablock pentablock pentablock triblock diblock random structure High A A A A A A B temperature endurance characteristics Relative 71 69 66 66 92 87 100 bending fraction (%)

(35) From the results of Table 2, in the case of using the block copolymer having the physically cross-linked structure added to the chemically cross-linked structure, excellent durability at high temperature conditions could be obtained over the random copolymer only capable of forming the chemical cross-linking. In particular, it could be confirmed that in the case of using the pentablock copolymer, it exhibits excellent bending suppression property by action as the stress relaxation points residing inside the physically cross-linking points over the case of using the triblock or diblock copolymer.

EXPLANATION OF REFERENCE NUMERALS

(36) 10: pressure-sensitive adhesive polarizing plate 100: optical film 110: primer layer 120: pressure-sensitive adhesive layer