KR101320835B1 - Thermosetting resin composition - Google Patents

Abstract

The present invention relates to a thermosetting resin composition and a protective film made of the composition, and to a thermosetting composition and a protective film made of the composition, which are preferable as a material for forming a protective film used for a color filter for an optical device, and having excellent surface hardness, A protective film having planarization, mechanical properties, UV resistance and heat resistance, and at the same time having sufficient adhesion with a substrate, acid resistance and alkali resistance, and no yellowing phenomenon at high temperature, thus is very suitable as a protective film forming material for an optical device. A thermosetting resin composition can be provided.

Description

Thermosetting resin composition

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermosetting resin composition and a protective film made of the composition, and more particularly to a thermosetting composition and a protective film made of the composition as a material for forming a protective film used for a color filter for an optical device.

Optical devices such as liquid crystal display devices (LCDs) are subjected to harsh processing such as immersion treatment with organic solvents, acids, alkali solutions, etc. during the manufacturing process, or localized high-temperature heating of the surface by sputtering when forming wiring electrode layers. Will receive. Therefore, in order to prevent the deterioration at the time of manufacture, these elements may provide a protective film in the surface.

The protective film protects the colored layer and serves to planarize the color filter. Therefore, the protective film must withstand such harsh treatments and at the same time have excellent adhesion to the substrate or lower layer, and have high flatness, surface hardness, transparency and excellent heat resistance and light resistance without deterioration such as coloring, yellowing and whitening over a long period of time. Required. Moreover, what is excellent in chemical-resistance, such as solvent resistance, acid resistance, and alkali resistance, water resistance, etc. is calculated | required. In addition, when applying such a protective film to the color filter of a color liquid crystal display element, it is preferable that the level | step difference of a general color filter can be planarized with a board | substrate.

The protective film composition is manufactured in the form of a curable resin composition so as to satisfy the above conditions, and largely classified into thermosetting and photocurable (photosensitive). When the patterning of the protective film is required, a photosensitive resin composition is required, but otherwise, a thermosetting resin composition is used, because it is convenient in the process and can increase the crosslinking density, thereby providing excellent mechanical properties and heat resistance.

Japanese Patent Application Laid-Open Nos. 2000-103937, 2000-119472 and 2000-143772 describe thermosetting resin compositions as compositions constituting a protective film. That is, the composition which consists of an acrylic resin containing a carboxyl group or an epoxy group, the polyfunctional monomer containing the ethylenically unsaturated group which functions as a crosslinking agent, and a thermal polymerization initiator is used.

However, when the protective film is prepared using these compositions, mechanical properties are not excellent, and in particular, yellowing phenomenon is often exhibited due to poor heat resistance at high temperatures. In consideration of the mechanical properties, the polyfunctional monomer containing an ethylenically unsaturated group can be used excessively. In this case, there is a problem that the yellowing phenomenon at a high temperature becomes more severe.

The present invention is to provide a thermosetting resin composition excellent in mechanical properties and heat resistance by effectively improving the crosslinking density and a protective film made of the composition.

In addition, the present invention is to provide a thermosetting resin composition and a protective film made of the composition that does not appear yellowing at high temperatures.

As a preferred embodiment of the present invention, a thermosetting resin comprising an unsaturated carboxylic acid or anhydride thereof (a1), an epoxy group-containing unsaturated compound (a2), a copolymer [A1] and a copolymer [A2] of an olefinically unsaturated compound (a3) In the composition, the copolymer [A1] has a number average molecular weight of 1,000 to 10,000, the copolymer [A2] provides a thermosetting resin composition, characterized in that the number average molecular weight of 10,000 to 100,000.

In the above embodiment, the copolymer [A1] may contain 10 to 200 parts by weight based on 100 parts by weight of the copolymer [A2].

In the above embodiment, it may further comprise a melamine resin as the curable compound [B], wherein the curable compound [B] may contain 0.1 to 10 parts by weight based on 100 parts by weight of the copolymer [A2].

The thermosetting resin composition according to the embodiment may further include a polymerizable compound [C] having an ethylenically unsaturated bond in an amount of 150 parts by weight or less based on 100 parts by weight of the copolymer [A2].

The thermosetting resin composition according to the embodiment may further include a thermal radical polymerization initiator in an amount of 20 parts by weight or less based on 100 parts by weight of the copolymer [A2].

As another preferred embodiment of the present invention, a protective film formed of the thermosetting resin composition is provided.

The thermosetting resin of the present invention has excellent planarization and mechanical properties, has no UV resistance and heat resistance, does not exhibit yellowing at high temperatures, and at the same time, a protective film having sufficient adhesion with a substrate, acid resistance and alkali resistance can be prepared. The thermosetting resin composition which is very suitable as a protective film formation material for devices can be provided.

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

The present invention provides a thermosetting resin composition comprising a thermosetting resin composition comprising a copolymer [A1] of an unsaturated carboxylic acid or an anhydride thereof (a1), an epoxy group-containing unsaturated compound (a2), and an olefinically unsaturated compound (a3).

The copolymer [A1] is obtained by a conventionally known polymerization method, that is, it can be synthesized by carrying out radical polymerization of compounds (a1), (a2) and (a3) in the presence of a polymerization initiator in a solvent.

In particular, it is preferable that the copolymer [A1] of this invention exists in the range of the number average molecular weight 1,000-10,000. This takes into account the surface flatness of the protective film to be manufactured later.

The copolymer [A1] preferably contains 5 to 40% by weight, more preferably 10 to 30% by weight of the structural unit derived from the compound (a1). When this structural unit is less than 5 weight%, the heat resistance, chemical resistance, and surface hardness of the protective film manufactured later tend to fall, and when it exceeds 40 weight%, there exists a problem that storage safety falls. Examples of the compound (a1) include monocarboxylic acids such as acrylic acid, methacrylic acid and crotonic acid; Dicarboxylic acids such as maleic acid, fumaric acid, citraconic acid, mesaconic acid and itaconic acid; And anhydrides of these dicarboxylic acids. One of these dicarboxylic acids may be used alone, or two or more dicarboxylic acids may be used in combination. Among them, acrylic acid, methacrylic acid, maleic anhydride and the like are mainly used because of their excellent copolymerization reactivity and heat resistance and easy availability.

In addition, the copolymer [A1] preferably contains 10 to 70% by weight, more preferably 20 to 60% by weight of the structural unit derived from the compound (a2). When this structural unit is less than 10 weight%, the heat resistance and surface hardness of the protective film produced later tend to fall, and when it exceeds 70 weight%, storage safety tends to fall. Examples of the compound (a2) include glycidyl acrylate, glycidyl methacrylate, α-ethyl acrylate glycidyl, α-n-propyl acrylate glycidyl, α-n-butyl acrylate glycidyl, and acrylic acid-3. , 4-epoxy butyl, methacrylic acid-3,4-epoxy butyl, acrylic acid-6,7-epoxy heptyl, methacrylic acid-6,7-epoxy heptyl, α-ethyl acrylic acid-6,7-epoxy heptyl, o It is used alone or in combination of two or more selected from -vinyl benzyl glycidyl ether, m-vinyl benzyl glycidyl ether, and p-vinyl benzyl glycidyl ether to improve the copolymerization reactivity and the heat resistance and hardness of the resulting protective film. It is preferably used in that point.

The copolymer [A1] preferably contains 10 to 70% by weight of the structural unit derived from the compound (a3), more preferably 20 to 50% by weight. When this structural unit is less than 10 weight%, storage stability tends to fall, and when it exceeds 70 weight%, the heat resistance and surface hardness of the protective film produced later tend to fall. Examples of the compound (a3) include methacrylic acid alkyl esters such as methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate and t-butyl methacrylate; Acrylic acid alkyl esters such as methyl acrylate and isopropyl acrylate; Methacrylic acid cycloalkyl esters such as cyclohexyl methacrylate, 2-methylcyclohexyl methacrylate, dicyclopentenyl methacrylate, dicyclopentenyloxyethyl methacrylate and isoboroyl methacrylate; Acrylic acid cycloalkyl esters such as cyclohexyl acrylate, 2-methyl cyclohexyl acrylate, dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate and isoboroyl acrylate; Methacrylic acid aryl esters such as phenyl methacrylate and benzyl methacrylate; Acrylic acid aryl esters such as phenyl acrylate and benzyl acrylate; Dicarboxylic acid diesters such as diethyl maleate, diethyl fumarate and diethyl itaconic acid; Hydroxy alkyl esters such as 2-hydroxy ethyl methacrylate and 2-hydroxy propyl methacrylate; And styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, vinyl toluene, p-methoxy styrene, acrylonitrile, methacrylonitrile, vinyl chloride, vinylidene chloride, acrylamide, methacrylamide, Vinyl acetate, 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, or a combination of two or more thereof. Among them, styrene, t-butyl methacrylate, dicyclopentenyl methacrylate, p-methoxy styrene, 2-methyl cyclohexyl acrylate, 1,3-butadiene and the like are preferred from the viewpoint of copolymerization reactivity and heat resistance.

The copolymer [A1] as used in the present invention has a carboxyl group and / or a carboxylic anhydride and an epoxy group, and can be easily cured by heating without using a special curing agent, but the above-mentioned curable compound [B] In the case of using, the crosslinking density can be sufficiently increased.

As a solvent used for the synthesis | combination of a copolymer [A1], Alcohol, such as methanol and ethanol; Ethers such as tetrahydrofuran, diethylene glycol dimethyl ether and diethylene glycol diethyl ether; One or a combination of two or more selected from propylene glycol alkyl ether acetates such as propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol propyl ether acetate, and propylene glycol butyl ether acetate is preferred.

As a polymerization initiator used for synthesis | combination of a copolymer [A1], what is generally known as a radical polymerization initiator can be used. Azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis- (2,4-dimethylvaleronitrile), 2,2'-azobis- (4-methoxy- Dimethylvaleronitrile); and the like; Organic peroxides such as benzoyl peroxide, t-butyl peroxypivalate, and 1,1'-bis- (t-butylperoxy) cyclohexane; And hydrogen peroxide. When a peroxide is used as a radical polymerization initiator, a peroxide can be used together with a reducing agent as a redox type initiator.

The thermosetting resin composition of the present invention is obtained by the same method as the copolymer [A1], and may further include a copolymer [A2] having a molecular weight of 10,000 to 100,000. That is, copolymer [A2] can synthesize | combine the compound (a1), (a2), and (a3) mentioned above by carrying out radical polymerization in presence of a polymerization initiator in a solvent. The content of the copolymer [A2] is preferably 10 to 200 parts by weight of the copolymer [A1] with respect to 100 parts by weight of the copolymer [A2] in consideration of the surface coating property of the protective film.

The thermosetting resin composition of the present invention may further include a curable compound [B], such a curable compound [B] is not particularly limited, it may be selected from a curable compound containing a melamine resin.

It is preferable to contain 0.1-10 weight part with respect to 100 weight part of copolymers [A2], and, as for the said curable compound [B], it is preferable to contain 3-10 weight part more preferably. When the content of the curable compound [B] is less than 0.1 part by weight based on 100 parts by weight of the copolymer [A2], it is difficult to obtain a protective film having a sufficiently high crosslink density, and there is a problem that various resistances of the protective film may be lowered. When the amount exceeds 10 parts by weight, a large amount of unreacted curable compound [B] is likely to remain in the film of the protective film to be obtained, and as a result, the property of the protective film is unstable or the adhesiveness tends to be lowered.

Meanwhile, the thermosetting resin composition of the present invention may further include a polymerizable compound [C] having an ethylenically unsaturated bond in addition to the copolymer [A1] and the curable compound [B].

The said polymeric compound [C] is preferable from a viewpoint that a monofunctional, bifunctional, or trifunctional or more (meth) acrylate has favorable polymerizability, and the heat resistance and surface hardness of the protective film obtained later improve.

As said monofunctional (meth) acrylate, 2-hydroxy ethyl (meth) acrylate, carbitol (meth) acrylate, isobornyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, 2- (meth) acryloyloxy ethyl 2-hydroxy propyl phthalate etc. are mentioned.

As said bifunctional (meth) acrylate, ethylene glycol (meth) acrylate, 1, 6- hexanediol (meth) acrylate, 1, 9- nonanediol (meth) acrylate, propylene glycol (meth) acryl The rate, tetraethylene glycol (meth) acrylate, bisphenoxy ethyl alcohol fluorene diacrylate, etc. are mentioned.

Examples of the above (meth) acrylate having three or more functional groups include (meth) acrylic esters such as trishydroxyethylisocyanurate tri (meth) acrylate, trimethylpropane tri (meth) acrylate, pentaerythritol tri Tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and the like.

It can be used as a polymeric compound [C] by 1 type or in combination of 2 or more types selected from such monofunctional, bifunctional, or trifunctional or more than (meth) acrylate.

The polymerizable compound [C] is preferably contained in an amount of 150 parts by weight or less based on 100 parts by weight of the copolymer [A2], and more preferably 120 parts by weight or less. When content of polymeric compound [C] exceeds 150 weight part with respect to 100 weight part of copolymers [A2], the adhesiveness of the protective film obtained will fall easily.

In addition, the thermosetting resin composition of the present invention may further include a thermal radical polymerization initiator, but is contained in a proportion of 20 parts by weight or less, more preferably 15 parts by weight or less, based on 100 parts by weight of the copolymer [A2]. When the thermal radical polymerization initiator exceeds 20 parts by weight, the heat resistance and planarization property of the protective film obtained later are likely to be lowered.

The thermal radical polymerization initiator may be one commonly known as a radical polymerization initiator, and may be a polymerization initiator used for polymerization of the copolymer [A1] described above.

The thermosetting resin composition of this invention can be manufactured by melt | dissolving a polymeric compound [C] and a thermal radical polymerization initiator selectively with a copolymer [A1] and curable compound [B] mentioned above in a solvent. The solvent used at this time does not react with any component. For example, a solvent used for the polymerization of the copolymer [A1] can be used, and among them, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, and propylene glycol methyl ether in view of solubility, reactivity, and convenience of coating film formation. Acetate is preferred. It is also possible to use a high boiling point solvent together with the above solvent. Examples of the high boiling point solvent include N, N-dimethylformamide, N-methylacetamide, N, N-dimethylacetamide, N-methylpyrrolidone, dimethylsulfoxide, And the like. When using such a high boiling point solvent together, it is preferable that the mixing ratio with the said solvent is "(the said solvent): (high boiling point solvent) = 100: 0-40".

In addition, the thermosetting resin composition of this invention may contain another component as needed within the scope of the technical idea of this invention. Other components herein include, for example, a surfactant for improving applicability. Examples of the surfactant include fluorine or silicone-based surfactants, and examples thereof include FC-129, FC-170C, and FC-430 from 3M. This can be used in an amount of 5 parts by weight or less, more preferably 2 parts by weight or less, based on 100 parts by weight of the copolymer [A2]. When using surfactant more than 5 weight part with respect to 100 weight part of copolymers [A2], there exists a problem which foams easily at the time of application | coating.

The thermosetting resin composition mixed as described above may be used after filtering using a filter having a diameter of about 0.1 ~ 5㎛.

The thermosetting resin composition of this invention can form a protective film by the following method, for example.

After applying a thermosetting resin composition to a board | substrate, removing a solvent and forming the coating film of a thermosetting resin composition, it can heat-process and can obtain a protective film.

As the substrate, glass, quartz, silicon, resin, or the like can be used, and examples of the resin include a ring-opening polymer of polyethylene terephthalate, polybutylene terephthalate, polyether sulfone, polycarbonate, polyimide and cyclic olefin, Hydrogenated products, and the like.

The method of applying the thermosetting resin composition solution is not particularly limited, and for example, a spray method, a roll coating method, a rotary coating method, or the like may be used.

The removal of the solvent is preferably performed by a heat treatment (preliminary firing). Although the conditions of such preliminary baking differ with kinds, ratios, etc. of each component of a composition solution, it is preferable to bake about 0.5 to 20 minutes at 60-120 degreeC.

Subsequent heat treatment, the treatment temperature at this time can be treated for 10 to 100 minutes at 150 ~ 300 ℃ to produce a protective film for an optical device.

The thickness of the protective film formed as described above is preferably 0.1 to 6 µm, and when the unevenness is formed on the substrate forming the protective film, the value should be understood as the value at the top of the unevenness.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

≪ Example 1 >

5 parts by weight of 2,2'-azobis isobutyronitrile and 200 parts by weight of diethylene glycol dimethyl ether were added to a reaction vessel equipped with a cooling tube and a stirrer. Subsequently, 20 parts by weight of styrene, 30 parts by weight of methacrylic acid, 40 parts by weight of glycidyl methacrylate, and 10 parts by weight of dicyclopentenyloxyethyl methacrylate were added thereto, followed by nitrogen replacement, and stirring was gradually started. The temperature of the solution was raised to 80 ° C. and maintained at this temperature for 4 hours to obtain a polymer solution containing copolymer [A1]. Obtained copolymer [A1] had a molecular weight of 5000 and solid content concentration of the copolymer solution was 33.0 weight%.

Then, 10 parts by weight of 2,2'-azobis isobutyronitrile and 200 parts by weight of diethylene glycol dimethyl ether were added to a reaction vessel equipped with another cooling tube and a stirrer. Subsequently, 20 parts by weight of styrene, 30 parts by weight of methacrylic acid, 40 parts by weight of glycidyl methacrylate, and 10 parts by weight of dicyclopentenyloxyethyl methacrylate were added thereto, followed by nitrogen replacement, and stirring was gradually started. The temperature of the solution was raised to 80 ° C. and maintained at this temperature for 4 hours to obtain a polymer solution containing copolymer [A2]. Obtained copolymer [A2] had a molecular weight of 20000 and a solid content concentration of the copolymer solution was 33.0% by weight.

67 weight part (solid content) of copolymer [A1] obtained, 100 weight part (solid content) of copolymer [A2], 5 weight part of L-110-60 as a curable compound [B], and 3M FC as surfactant. 0.1 parts by weight of -430 (fluorine-based surfactant) was mixed and dissolved in 100 g of diethylene glycol dimethyl ether and 10 g of N-methyl pyrrolidone to give a solid concentration of 25%. Then, it filtered by the filter of 0.45 micrometers of pore diameters, and manufactured the thermosetting resin composition solution.

The thermosetting resin composition solution was coated on the glass substrate using a spin coater to have a thickness of 2 μm, and then fired at 220 ° C. for 30 minutes in a clean oven to form a protective film on the glass substrate.

<Example 2>

A thermosetting resin composition solution was prepared in the same manner as in Example 1, except that 15, by weight of 2,2′-azobis isobutyronitrile was obtained to prepare a copolymer [A2] having a molecular weight of 20000. A protective film was formed on the glass substrate in the same manner.

<Example 3>

A thermosetting resin composition solution was prepared in the same manner as in Example 1, except that 20, by weight of 2,2′-azobis isobutyronitrile was prepared to obtain a copolymer [A1] having a molecular weight of 5,000. A protective film was formed on the glass substrate in the same manner.

&Lt; Comparative Example 1 &

A thermosetting resin composition solution was prepared in the same manner as in Example 1, except that copolymer [A2] was not used, and a protective film was formed on the glass substrate by the same method.

Comparative Example 2

A thermosetting resin composition solution was prepared in the same manner as in Example 3, except that copolymer [A2] was not used, and a protective film was formed on the glass substrate by the same method.

&Lt; Comparative Example 3 &

A thermosetting resin composition solution was prepared in the same manner as in Example 1 except that the copolymer [A1] was not used, and a protective film was formed on the glass substrate in the same manner.

The evaluation method of the protective film used in the present invention is as follows, and the evaluation results of the protective film prepared in the above Examples and Comparative Examples are shown in Table 1 below.

(1) Adhesiveness

According to the checkered tape method (Pressure Cooker test method, 150 degreeC, 100% of relative humidity, 2 hours), 100 checkerboard scales were formed in the protective film by the cutter knife, and the adhesive test was done. The number of the checkerboard scales which peeled was measured, and the adhesiveness of a protective film was evaluated by the following criteria.

○: Number of peeled checkered patterns No more than 5

B: Number of peeled checkered patterns 6 to 49

×: 50 or more pieces of checkered patterns

(2) Surface hardness

The surface hardness of the protective film was evaluated by performing a pencil hardness test method on the protective film according to the pencil hardness method.

(3) coating property

The number of particles was measured on the surface of the protective film at 9 sites in a 2 inch x 2 inch area through an optical microscope, and the coating property of the protective film was evaluated according to the following criteria.

○: 10 or less particles

△: total particle number 10-30

×: 30 or more total particles

(4) transparency

The transmittance of the protective film was measured at 400-700 nm using a spectrophotometer (UV-3101, Shimadzu Corp.), and the transparency of the protective film was evaluated according to the following criteria.

○: Minimum transmittance exceeded 95%

?: Minimum transmittance: 90 to 95%

X: less than 90% of the lowest transmittance

(5) flatness

The surface irregularities of the protective film were irradiated using the α step, and the step difference of the substrate was measured.

(6) UV resistance

The protective film was irradiated with UV (24 mW, 40 seconds). The transmission spectrum of the protective film before and after UV irradiation was measured, and UV resistance of the protective film was evaluated by the following criteria.

?: Transmission spectrum change within 1%

X: 1% or more of change in transmission spectrum

(7) Heat resistance (degree of yellowing)

The protective film was heated in a clean oven at 240 ° C. for 60 minutes, the transmission spectrum before and after heating was measured, and the heat resistance and the degree of yellowing of the protective film were evaluated by the following criteria.

○: Transmission spectrum change within 1% (no yellowing phenomenon)

X: 1% or more of change in transmission spectrum (with yellowing)

(8) acid resistance

After the glass substrate on which the protective film was formed was immersed in a 25 wt% aqueous hydrochloric acid solution for 30 minutes at 30 ° C., the appearance change of the protective film was observed to evaluate the acid resistance of the protective film.

(9) alkali resistance

After the glass substrate on which the protective film was formed was immersed in a 10 wt% sodium hydroxide aqueous solution for 30 ° C. for 60 minutes, the appearance change of the protective film was observed to evaluate the alkali resistance of the protective film.

division Adhesiveness Surface hardness Coating property Transparency Flatness UV resistance Heat resistance Acid resistance Alkali resistance Example 1 ○ 5H ○ ○ 0.1 μm ○ ○ No change No change Example 2 ○ 5H ○ ○ 0.1 μm ○ ○ No change No change Example 3 ○ 5H ○ ○ 0.1 μm ○ ○ No change No change Comparative Example 1 ○ 3H × ○ 0.3 μm × × No change No change Comparative Example 2 ○ 3H × ○ 0.3 μm × × No change No change Comparative Example 3 ○ 3H × ○ 0.3 μm × × No change No change

As a result of the physical property measurement, when the thermosetting resin of the present invention is used to form the color filter protective film on the substrate, it can be seen that surface hardness, planarization, UV resistance and heat resistance are particularly superior to the comparative example. Therefore, when the thermosetting resin of the present invention is applied to a protective film, it can be seen that yellowing phenomenon can be prevented due to excellent heat resistance while satisfying the characteristics as a protective film, and can provide a protective film having excellent mechanical properties.

Claims (6)

In the thermosetting resin composition containing an unsaturated carboxylic acid or its anhydride (a1), an epoxy group containing unsaturated compound (a2), a copolymer [A1] and a copolymer [A2] of an olefinic unsaturated compound (a3), The copolymer [A1] has a number average molecular weight of 1,000 to 10,000, the copolymer [A2] has a number average molecular weight of 10,000 to 100,000, and the copolymer [A1] is based on 100 parts by weight of the copolymer [A2]. It contains 10-200 weight part, The thermosetting resin composition characterized by the above-mentioned. delete The method of claim 1, Melamine resin is further contained as curable compound [B], The said curable compound [B] is 0.1-10 weight part with respect to 100 weight part of said copolymers [A2], The thermosetting resin composition characterized by the above-mentioned. The method of claim 1, The thermosetting resin composition further comprises a polymerizable compound [C] having an ethylenically unsaturated bond in an amount of 150 parts by weight or less based on 100 parts by weight of the copolymer [A2]. The method of claim 1, The thermosetting resin composition further comprises a thermal radical polymerization initiator in an amount of 20 parts by weight or less based on 100 parts by weight of the copolymer [A2]. The protective film for optical devices formed from the composition of any one of Claims 1-5.