WO2005057285A1

WO2005057285A1 - Thermal curable one-liquid type epoxy resin composition for over-coat

Info

Publication number: WO2005057285A1
Application number: PCT/KR2004/003221
Authority: WO
Inventors: You-Lee Pae; Young-Keun Kim; Suk-Young Choi; Hyuk-Jin Cha; Jae-Hwan Lee; Mi-Sun Ryu; Seung-Woo Woo; Kwon-Yil Yoo; Su-Hyun Lee; Yong-Man Jeong; Bum-Young Choi; Cheol Han; Woong Kim; Nak-Chil Jung; Min-Ji Kim; Young-Soo Choi; Sang-Hyup Jung; Jae-Lok Choi
Original assignee: Samyangems Co., Ltd.
Priority date: 2003-12-09
Filing date: 2004-12-09
Publication date: 2005-06-23
Also published as: KR100579833B1; KR20050055943A

Abstract

Provided is a thermal curable one-liquid type epoxy resin composition for overcoat. The composition includes 100 parts by weight of binder resin, 0.1-100 parts by weight of latent curing agent, and 0.1-100 parts by weight of silicon-based compound having epoxy group. The composition has high heat resistance, transparency, film retention, degree of planarization, and adhesion, as well as high storage stability, and thus, can be useful as an overcoat of a color filter used for a thin film transistor-liquid crystal display (TFT-LCD).

Description

THERMAL CURABLE ONE-LIQUID TYPE EPOXY RESIN COMPOSITION FOR OVER-COAT

TECHNICAL FIELD The present invention relates to a thermal curable one-liquid type epoxy resin

composition which is used to form an overcoat of a color filter used for a thin film

transistor-liquid crystal display (TFT-LCD), etc.

BACKGROUND ART A thin film transistor-liquid crystal display (TFT-LCD) is one of the most

rapidly developing flat display devices and expected to lead the market for display

devices. To manufacture large TFT-LCDs, a large glass plate should be used and a

color filter layer should be planarized on the glass plate. Thus, there is a need to develop materials of forming an overcoat to planarize the color filter layer. Materials of an overcoat are usually either UV curable or thermal curable. As

the glass plate is larger, it is more difficult to expose the entire surface of the overcoat to UV light at once. Thus, thermal curable overcoats are more needed. However, as conventional thermal curable overcoats are two-liquid epoxy type and have low storage

stability, a mixture of a binder solution with a hardner solution must be used within

several hours after mixing, which is disadvantageous in view of efficiency of

manufacturing processes.

DISCLOSURE OF INVENTION

The present invention is designed to solve the problems of the prior art, and therefore it is an object of the present invention to provide a thermal curable one-liquid

type epoxy resin composition for overcoat, which has high heat resistance, transparency,

film retention, degree of planarization, and adhesion, as well as high storage stability,

and thus, can be useful as an overcoat of a color filter used for a thin film

transistor-liquid crystal display (TFT-LCD), etc.

To achieve the above mentioned object, the present invention provides a thermal

curable one-liquid type epoxy resin composition for overcoat, comprising: 100 parts by

weight of a binder resin having the following formula 1; 0.1-1 OO parts by weight of at

least one latent curing agent selected from the group consisting of a compound having

the following formula 2, a compound having the following formula 3, a compound

having the following fomiula 4, a compound having the following formula 5, a compound having the following formula 6, and a compound having the following

formula 7; and 0.1-100 parts by weight of a silicon-based compound having epoxy

group.

,(A)^(B^(C)_r Γ

In the formula 1, A is a monomer having epoxy group, for example, but not

limited to, glycidyl acrylate, glycidyl methacrylate, glycidyl-α-ethyl acrylate,

glycidyl-α-n-propylacrylate, glycidyl-α-butylacrylate, 3,4-epoxybutyl methacrylate,

3,4-epoxybutyl acrylate, 6,7-epoxyheptyl methacrylate, 6,7-epoxyheptyl acrylate,

6,7-epoxyheptyl-α -ethylacrylate, or the like. B is a monomer having carboxylic group and selected from acrylic acid and methacrylic acid. C is styrene or an acryl or methacryl monomer having 1-14 carbon atoms, for example, but not limited to, styrene, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, methyl acrylate, ethyl acrylate, cyclohexyl acrylate, isobornyl methacrylate, isobornyl acrylate, hydroxyethyl methacrylate, dimethylamino ethyl methacrylate, acryl amide, or the like. 1, m, and n means molar numbers of A, B and C, which are 0.1-90mol%, 0-70mol%, and 0.1-90mol% respectively.

In the formula 2, Rj is alkyl group or εryl group.

In the formula 3, R₂ is alkyl group or aryl group, <Formula 4>

ΘΘ R₃R4IX

In the formula 4, R₃ and } are independently aryl group, and ^ is one

selected from the group consisting of

6 _} and

SbF₆ ^Θ

R5 RΘ R75X

In the formula 5, R₅, Re and R₇ are independently aryl group or substituted aryl group, and ^Λ is one selected from the group consisting of ^' 3° ^3 ₅ ^r4 ,

PF? _, AsF? _{, md} SbF_β ^Θ

In the formula 6, R₈, R₉, R₁₀, and Rπ are independently alkyl group or aryl group,

and is one selected from the group consisting of _^ 4 , 6 .

AsF^ and SbF^

In the formula 7, Rj₂ and R₁₃ are independently alkyl group or aryl group. In the thermal curable one-liquid type epoxy resin composition for overcoat according to the present invention, the compound having the formula 2 can be at least one compound selected from phthalic anhydride, tetrahydrophthalic anhydride, hexa-hydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyl endomethylene tetra-hydrophthalic anhydride, hexachloroendomethylene tetra-hydrophthalic anhydride, dodecyl succinic anhydride, trimellitic anhydride, and the like. The compound having the formula 3 can be at least one compound selected from pyromellitic dianhydride and benzophenone tetra-carboxylic acid dianhydride. Each of the compounds having the formulas 4 to 7 can be selected from diphenyl iodonium trifluoromethane sulfonate, diphenyl iodonium nonafluorobutane sulfonate, di-(4-t-butylbenzene)iodonium trifluoromethane sulfonate, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluorobutanesulfonate, diphenyl 4-methylphenyl sulfonium

trifluoromethanesulfonate, S-(2-naphthalenecarbonylmethyl) tetrahydrothiophenium

trifluoromethanesulfonate, dimethyl(4-naphthol)sulfonium trifluoromethanesulfonate,

N-succinimidyl 10-camphorsulfonate,

N-( 1 ,2,4,6-tetrahydrophthalimidyl)-P-toluenesulfonate,

N-( 1 ,8-naphthalenedicarboximidyl)- 10-camphorsulfonate, N-(l,8-naphthalenecarboximidyl)-ρ-toluenesulfonate, and the like.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects and aspects of the present invention will become apparent from the

following description of embodiments with reference to the accompanying drawing in

which:

FIG. 1 is a schematic view of a color filter for a thin film transistor-liquid crystal

display (TFT-LCD), the color filter having an overcoat formed thereon; FIG. 2 is a graph showing thermogravimetric decomposition of the thermal curable one-liquid type epoxy resin composition prepared in Example 1, after thermal

curing; and FIG. 3 is a graph showing transparency of the thermal curable one-liquid type

epoxy resin composition prepared in Example 1, after thermal curing.

BEST MODES FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in more detail.

A thermal curable one-liquid type epoxy resin composition for overcoat according to the present invention includes binder resin having the formula 1 described

above. In the formula 1, monomer A increases adhesion of the composition, monomer

B aids to cure an epoxy, thereby decreasing a curing time, and monomer C increases

durability of a film formed of the composition. The copolymer having the formula 1

can be produced by a radical polymerization reaction in the presence of a radical

polymerization initiator and a solvent. Preferably, the binder resin having the formula

1 has an average molecular weight of 2,000-100,000, a dispersity of 1.0-5.0, and an acid

value of 0-400 KOHmg/g. More preferably, the binder resin having the formula 1 has

an average molecular weight of 5,000-60,000, a dispersity of 1.6-3.0, and an acid value of 0-150 KOHmg/g.

The thermal curable one-liquid type epoxy resin composition of the present

invention includes 0.1-100 parts by weight of at least one latent curing agent selected

from a compound having the formula 2, a compound having the formula 3, a compound

having the formula 4, a compound having the formula 5, a compound having the

formula 6, and a compound having the formula 7, based on a total solid content of the resins.

The compound having the formula 2 is dicarboxylic acid cyclic anhydride and itsexamples include, but not limited to, phthalic anhydride, tetrahydrophthalic anhydride, hexa-hydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyl endomethylene tetra-hydrophthalic anhydride, hexachloroendomethylene tetra-hydrophthalic anhydride, dodecyl sαccinic anhydride, trimellitic anhydride, and the like. The compound having the formula 3 is tetracarboxylic acid dianhydride and its examples include, but not limited to, pyromellitic dianhydride, benzophenone tetra-carboxylic acid dianhydride, and the like. Both the compound having the formula 2 and the compound having the formula 3 are nonionic-type latent curing agents.

The compounds having formulas 4 to 7 are acid generator-type latent curing agents and their examples include, but not limited to, diphenyl iodonium trifluoromethane sulfonate, diphenyl iodonium nonafluorobutane sulfonate, di-(4-t-butylbenzene)iodonium trifluoromethane sulfonate, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluorobutanesulfonate, diphenyl 4-methylphenyl sulfonium trifluoromethanesulfonate, S-(2-naphthalenecarbonylmethyl) tetrahydrothiophenium trifluoromethanesulfonate, dimethyl(4-naphthol)sulfonium trifluoromethanesulfonate, N-succinimidyl

10-camphorsulfonate, N-( 1 ,2,4,6-tetrahydrophthalimidyl)-P-toluenesulfonate,

N-(l,8-naphthalenedicarboximidyl)-10-camphorsulfonate,

N-(l,8-naphthalenecarboximidyl)-p-toluenesulfonate, and the like. By changing the types and compositions of the binder resin having the formula 1, the nonionic-type latent curing agents, and the acid generator-type latent curing agents, the overcoat can have desired physical properties.

The thermal curable one-liquid type epoxy resin composition of the present

invention includes 0.1-100 parts by weight of silicon-based compound having epoxy

group, based on a total solid content of the resins. The silicon-based compound increases adhesion of the composition and heat resistance after curing. Preferably the

silicon-based compound having epoxy group is, but not limited to,

(3-glycidoxypropyl)trimethoxy(ethoxy)silane, (3-glycidoxypropyl)methyldimethoxy(ethoxy)silane, (3-glycidoxypropyl)

dimethylmethoxy(ethoxy)silane, 3,4-epoxybutyltrimethoxy(ethoxy)silane,

2-(3,4-epoxycyclohexyl)ethyltrimethoxy(ethoxy)silane, or the like.

The above compositional components are added to a solvent, thus obtaining the

composition. Advantageously, the solvent is an organic solvent which is highly

compatible with the binder resin, the latent curing agent, and other additives. For this

purpose, the solvent can be, but not limited to, at least one solvent selected from ethyl

acetate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate (EEP), ethyl

lactate, propylene glycol methyl ether acetate (PGMEA), propylene glycol methyl ether,

propylene glycol propyl ether, methyl cellosolve acetate, ethyl cellosolve acetate,

diethylene glycol methyl(or ethyl) acetate, acetone, methyl isobutyl ketone,

cyclohexanone, dimethylformamide (DMF), N,N-dimethylacetamide (DMAc),

N-methyl-2-pyrrolidone (NMP), γ-butyrolactone, diethyl ether, ethylene glycol dimethyl

ether, diglyme, tetrahydrofuran (THF), methanol, ethanol, propanol, iso-propanol, methyl(or ethyl) cellosolve, diethylene glycol methyl(or ethyl) ether, dipropylene glycol

methyl ether, toluene, xylene, hexane, heptane, octane, and the like.

It is preferable that the thermal curable one-liquid type epoxy resin composition

has a viscosity of 2-20 cps so as to control its coating property and solid content.

When the composition has a viscosity of 2-20 cps, pinholes are not generated in the thin

film formed after coating and a thickness of the thin film can be more easily controlled. More preferably, the composition has a viscosity of 10-15 cps. The thermal curable one-liquid type epoxy resin composition according to the

present invention may further include conventional levelling agent, defoaming agent, etc. in appropriate amounts, and if necessary, any additive which is compatible with the

other components, such as, a surfactant, a stabilizer, a sensitizer, an anti-striation agent,

a plasticizer, etc.

Hereinafter, the present invention will be described in more details. However,

it should be understood that the detailed description and a specific example, while

indicating preferred embodiments of the invention, are given by way of illustration only,

since various changes and modifications within the spirit and scope of the invention will

become apparent to those skilled in the art from this detailed description.

Examples

According to the components and compositions listed in Tables 1-5, a binder

resin solution having the formula 1 (A = glycidyl methacrylate, B = methacrylic acid, C

= methyl methacrylate, average molecular weight = 50,000, dispersity = 2.5), a latent

curing agent, a silicon-based compound having epoxy group, other additives, and then, a

solvent were added sequentially to a reactor equipped with a stirrer, and then stirred at room temperature. A viscosity of the resist composition was adjusted to 10-15 cps using the solvent. The term "balance" in Tables refers to an amount of the solvent

(expressed in parts) which must be added to the binder resin, the latent curing agent, the

silane-based epoxy compound, and the additives for the total mass of the composition to be 1 kg.

In Examples, the latent curing agents I through XXIII represent phthalic

anhydride(I), tetrahydrophthalic anhydride(II), hexa-hydrophthalic anhydride(III), methyltetrahydrophthalic anhydride(IV), methylhexahydrophthalic anhydride(V), methyl endomethylene tetra-hydrophthalic anhydride(VI), hexachloroendomethylene

tetra-hydrophthalic anhydride(VII), dodecyl succinic anhydride(VIII), trimellitic

anhydride(IX), pyromellitic dianhydride(X), benzophenone tetra-carboxylic acid

dianhydride(XI), diphenyl iodonium trifluoromethane sulfonate(XII), diphenyl iodonium

nonafluorobutane sulfonate(XIII), di-(4-t-butylbenzene)iodonium trifluoromethane

sulfonate(XIV), triphenylsulfonium trifluoromethanesulfonate(XV), triphenylsulfonium

nonafluorobutanesulfonate(XVI), diphenyl 4-methylphenyl sulfonium

trifluoromethanesulfonate(XVII), S-(2-naphthalenecarbonylmethyl)

tetrahydrothiophenium trifluoromethanesulfonate(XVIII),

dimethyl(4-naphthol)sulfonium trifluoromethanesulfonate(XIX), N-succinimidyl

10-camphorsulfonate(XX), N-( 1 ,2,4,6-tetrahydrophthalimidyl)

-P-toluenesulfonate(XXI),

N-(l,8-naphthalenedicarboximidyl)-10-camphorsulfonate(XXII), and

N-(l ,8-naphthalenecarboximidyl)-p-toluenesulfonate (XXIII), respectively.

Comparative Examples

The compositions were prepared in the same manner as in the Examples, except

that the binder resin having the following formula 8 was used in place of the binder

resin having the formula 1 and the components and compositions listed in Table 6 were used.

In the formula 8, n is 1-10.

Evaluations of the resist compositions prepared in Examples and Comparative

Examples were performed on a substrate such as a silicon wafer or a glass substrate.

Thermal property, UV transmittance, film retention, storage stability, and adhesion of

the compositions were tested as follows. The results are shown in Table 7.

(1) Thermal property

To evaluate the thermal properties of the compositions, thermal decomposition

temperatures of the compositions were measured using thermogravimetric analysis

(TGA) based on an initial decomposition temperature, in which 5% of the initial weight is lost.

(2) UV transmittance Each of the compositions was applied on a substrate using a spin coater at 500

rpm for 20 seconds, pre-baked at 90 ^°C for 5 minutes, and then, post-baked at 220 ^°C for

60 minutes to form a resist layer. Next, UV was transmitted and then UV

transmittance was measured.

(3) Film retention Each of the compositions was spin-coated on a substrate. The thickness ratio

(%) between layers formed by pre-baking and post-baking, respectively, was measured.

(4) Storage stability After the compositions were stored at room temperature for 1 month, a viscosity

change between before and after the storage was measured for each of the compositions. If the viscosity change is less than 5 cps, the storage stability was rated as "good". If

the viscosity change is at least 5 cps, the storage stability was rated as "bad".

(5) Adhesion

Film formed on a silicon wafer using each of the compositions was divided into

100 equal parts of line pattern using cross-cut blades. Tape was applied on the film, and then pulled off from the substrate in upward direction. If the pattern was not

peeled off, the adhesion was rated as "good. If the pattern was peeled off, the adhesion

was rated as "bad".

Table 1

Table 2

Table 3

Table 4

Table 5

Table 6

Table 7

As shown in the table 7, it was confirmed that the thermal curable one-liquid

type epoxy resin compositions according to the present invention including the binder

resin having the formula 1 and at least one latent heat curing agents selected from the

compounds having the fonnulas 2 to 7 had higher storage stability, heat resistance, transparency, film retention, degree of planarization, and adhesion to a glass surface.

FIG. 1 is a schematic view of a color filter layer for a TFT-LCD, the color filter having an overcoat formed thereon. FIG. 2 is a graph showing thermogravimetric decomposition of the overcoat resist prepared from the composition of Example 1 , after

thermal curing. Refening to FIG. 2, it exhibits a stable thermal property up to 325 ^°C .

FIG. 3 is a graph showing thermogravimetric decomposition of the thermal curable

one-liquid type epoxy resin composition prepared in Example 1, after thermal curing.

Referring to FIGS. 2 and 3, the composition prepared in Example 1 exhibits high

thermal stability and has a transmittance of 98% or more at 400 nm after thermal curing.

INDUSTRIAL APPLICABILITY As described above, a thermal curable one-liquid type epoxy resin composition

for overcoat according to the present invention has high heat resistance, transparency,

film retention, degree of planarization, and adhesion, as well as high storage stability.

Further, by changing a structure of a binder resin or the type or compositional ratio of a latent curing agent, the overcoat can have desired physical properties. Thus, the

thermal curable one-liquid type epoxy resin composition according to the present

invention can be useful as an overcoat of a color filter used for a thin film transistor-liquid crystal display (TFT-LCD).

Claims

What is claimed is:

1. A thermal curable one-liquid type epoxy resin composition for overcoat,

comprising: 100 parts by weight of a binder resin having the following formula 1 ;

0.1-100 parts by weight of at least one latent curing agent selected from the

group consisting of a compound having the following formula 2, a compound having the

following formula 3, a compound having the following formula 4, a compound having

the following formula 5, a compound having the following formula 6, and a compound

having the following formula 7; and

0.1-100 parts by weight of a silicon-based compound having epoxy group;

^■<^A <^BkA

wherein A is a monomer having epoxy group,

B is a monomer having carboxylic group, which is acrylic acid or methacrylic

acid, C is styrene or an acryl or methacryl monomer having 1-14 carbon atoms, and 1, m, and n are molar numbers of A, B and C , which are 0.1-90mol%, 0-70mol%,

and 0.1-90mol% respectively;

wherein Rj is alkyl group or aryl group;

wherein R₂ is alkyl group or aryl group;

©Θ R3R4IX

wherein R₃ and 1^ are independently aryl group, and

, PF₆ AsF₆ and SbF₆ ^Θ

wherein R₅, R^ and R₇ are independently aryl group or substituted aryl group, and is one selected from the group consisting of ^' S^¹^ _; t ι~4 ,

ΘΘ RβRgRioRi 1 NX

wherein R₈, R , Rio, and Rn are independently alkyl group or aryl group, and

<Formula 7> ₃

wherein Rj₂ and R]₃ are independently alkyl group or aryl group.

2. The thermal curable one-liquid type epoxy resin composition for overcoat

according to claim 1 , wherein the binder resin having the formula 1 has an average molecular weight

of 2,000-100,000, a dispersity of 1.0-5.0, and an acid value of 0-400 KOHmg/g.

3. The thermal curable one-liquid type epoxy resin composition for overcoat

according to claim 1, wherein the compound having the formula 2 is one selected from the group

consisting of phthalic anhydride, tetrahydrophthalic anhydride, hexa-hydrophthalic

anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyl endomethylene tetra-hydrophthalic anhydride, hexachloroendomethylene

tetra-hydrophthalic anhydride, dodecyl succinic anhydride, and trimellitic anhydride.

4. The thermal curable one-liquid type epoxy resin composition for overcoat according to claim 1, wherein the compound having the formula 3 is pyromellitic dianhydride or benzophenone tetra-carboxylic acid dianhydride.

5. The thermal curable one-liquid type epoxy resin composition for overcoat

according to claim 1 , wherein the compounds having the formulas 4 to 7 are independently selected

from the group consisting of diphenyl iodonium trifluoromethane sulfonate, diphenyl

iodonium nonafluorobutane sulfonate, di-(4-t-butylbenzene)iodonium trifluoromethane

sulfonate, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium

nonafluorobutanesulfonate, diphenyl 4-methylphenyl sulfonium

N-succinimidyl 10-camphorsulfonate,

N-( 1 ,2,4,6-tetrahydrophthalimidyl)-P-toluenesulfonate,

N-( 1 ,8-naphthalenedicarboximidyl)- 10-camphorsulfonate, and

N-(l ,8-naphthalenecarboximidyl)-p-toluenesulfonate.

6. The thermal curable one-liquid type epoxy resin composition for overcoat according to claim 1, wherein the silicon-based compound having epoxy group comprises at least one

selected from the group consisting of (3-glycidoxypropyl)trimethoxy(ethoxy)silane,

(3 -glycidoxypropy 1) methyldimethoxy(ethoxy)silane, (3 -glycidoxypropy 1)

dimethylmethoxy(ethoxy) silane, 3,4-epoxybutyltrimethoxy(ethoxy)silane, and

2-(3 ,4-epoxycyclohexyl) ethyltrimethoxy(ethoxy)silane

7. The thermal curable one-liquid type epoxy resin composition for overcoat

according to claim 1 , further comprising a solvent such that a viscosity of the composition is 2-20 cps.

8. The thermal curable one-liquid type epoxy resin composition for overcoat

according to claim 7, wherein the solvent includes at least one selected from the group consisting of

ethyl acetate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate (EEP),

ethyl lactate, propylene glycol methyl ether acetate (PGMEA), propylene glycol methyl

ether, propylene glycol propyl ether, methyl cellosolve acetate, ethyl cellosolve acetate,

diethylene glycol methyl(or ethyl) acetate, acetone, methyl isobutyl ketone,

cyclohexanone, dimethylformamide (DMF), N,N-dimethylacetamide (DMAc),

ether, diglyme, tetrahydrofiiran (THF), methanol, ethanol, propanol, iso-propanol, methyl(or ethyl) cellosolve, diethylene glycol methyl(or ethyl) ether, dipropylene glycol

methyl ether, toluene, xylene, hexane, heptane, and octane.