TWI583705B - Styrene-anhydride-acrylate copolymer containing ester or amido group and preparation and uses thereof - Google Patents

Description

Styrene-anhydride-acrylate copolymer containing ester group or guanamine group, preparation method and use thereof

The present invention relates to a terpolymer containing an ester group or a guanamine group, which is composed of a styrene monomer, a cyclic unsaturated acid anhydride monomer and an acrylate monomer, and is on the side. The chain carries a functional group such as a carboxylic acid group, an ester group or a guanamine group. The present invention also relates to a process for the preparation of the copolymer and its use, and in particular to a resin composition for an alkali-soluble negative photoresist.

In the field of printed circuit boards, it is known that a photosensitive resin composition having excellent properties can be used as a photoresist. The photoresist is classified into a positive photoresist and a negative photoresist depending on whether the exposed region can be removed or retained during development. Negative photoresist exhibits better adhesion to a variety of substrates, such as semiconductor substrates (germanium, gallium arsenide, indium phosphide, etc.) and metals (such as gold, copper, aluminum, etc.) than positive photoresists. And more resistant to acid. Its raw materials are also less expensive than positive photoresists.

A copolymer of styrene and maleic anhydride monoester is a photosensitive resin commonly used in printed circuit boards. In recent years, it has been studied extensively by first-stage polymerization of styrene and maleic anhydride. Copolymerization, followed by monoesterification of the maleic anhydride group on the copolymer with saturated or unsaturated alcohols.

CN1114629C discloses a photosensitive copolymer containing unsaturated bond branches, the main chain is composed of an unsaturated bond-containing monomer containing no acid anhydride group and an unsaturated bond-containing acid anhydride monomer, and the branched chain is an acid anhydride functional group and The alcohol of the unsaturated bond undergoes a monoesterification ring opening, and the ring-opened carboxylic acid group reacts with the epoxy ethyl compound to produce an ester group. CN1114629C is limited to the modification on the branch, and the degree of adjustment of the physical properties of the resin is limited.

TW450980B discloses a ruthenium-amine-modified styrene-maleic anhydride copolymer, a main chain composed of styrene-maleic anhydride, an acid anhydride moiety thereof and a ring-opening reaction with a secondary amine, and the intermediate product is The acrylate reacts to form a side chain having a guanamine group and an acid group.

CN 104017128A discloses an alkali-soluble photosensitive resin prepared by using a maleic anhydride ring-opening modified branched oligomer, wherein the oligomer is a tetrapolymer, and the monomer is methacrylic acid, benzyl methacrylate, maleic anhydride and The p-vinylbenzyl mercaptan was opened with maleic anhydride in the copolymer as hydroxyethyl acrylate. The para-vinylbenzyl mercaptan used in CN104017128A is not stable, and is easily deteriorated at 35 ° C or higher, and has an unpleasant odor, so it is limited in practical application.

In order to improve the resolution and fine line adhesion, one method is to use a copolymer containing a copolymer which is easily pyrolyzable and an inorganic powder photosensitive paste, and US Pat. No. 6,103,452 A discloses a photosensitive composition comprising (A) a carboxyl group-containing photopolymer. The polymer is prepared by reacting (a) an acid anhydride containing an unsaturated double bond and (b) a copolymer containing an unsaturated double bond compound with (c) a compound having a hydroxyl group-unsaturated double bond; (B) a diluent; (C) photopolymerization initiator; (D) inorganic powder and (E) stabilizer, that is, the polymer backbone is composed of an anhydride containing an unsaturated double bond (for example, maleic anhydride) and an unsaturated double bond-containing compound ( For example, styrene) is formed.

None of the foregoing documents mentions fine line adhesion and development resolution. Accordingly, there is still a need in the art for a photoresist composition which has a fast film removal speed and excellent chemical resistance (e.g., acid resistance) while maintaining fine line adhesion and development resolution.

The present invention provides a terpolymer containing an ester group or a guanamine group, which is a styrene composed of a styrene monomer, a cyclic unsaturated acid anhydride monomer, and an acrylate monomer. An acid anhydride-acrylate copolymer having a functional group such as a carboxylic acid group, an ester group or a guanamine group in the side chain.

According to the present invention, the physical properties of the resin are adjusted in addition to the functional groups on the side chain by ring-opening the cyclic anhydride portion of the polymer backbone, and the third monomer acrylate introduced in the copolymer backbone. The monomer can also adjust the physical properties of the resin. Further, the acrylate monomer may optionally contain a functional group selected from the group consisting of a hydroxyl group, a halogen group, an alkyl group, an epoxy group, an aryl group, and a combination thereof, and the use of the third monomer may provide a wider application level. Resin upgrading method.

For example, when applied to an alkali-soluble photoresist, the present invention provides better film formation and acid resistance, and exhibits excellent acid resistance while exhibiting excellent resolution and fine line adhesion.

The styrene-based monomer used in the present invention is a monomer containing a styrene moiety, and may be, for example, styrene or α-methylstyrene, wherein the benzene ring moiety may be optionally substituted with a substituent. Substituents include, but are not limited to, halogen, _C1-6 straight or branched alkyl. In the preparation of the styrene-anhydride-acrylate copolymer of the present invention, the styrene monomer is used in an amount of 20 to 65 mol%, preferably 30 to 55 mol, and most preferably 35 to 45 mol%.

The cyclic unsaturated acid anhydride monomer used in the present invention is formed by an internal condensation reaction of an unsaturated di- or polycarboxylic acid, and examples thereof are maleic anhydride, citraconic anhydride, itaconic anhydride, cis-aconitic anhydride, trans-aconitic anhydride, pentene. Diacid anhydride, viscous anhydride (2,4-hexadiene anhydride; also known as 2,7- Anthraquinone) and the like. In the preparation of the styrene-anhydride-acrylate copolymer of the present invention, the unsaturated acid anhydride monomer is used in an amount of 20 to 50 mol%, preferably 20 to 40 mol%, most preferably 30 to 40 mol%. .

The acrylate-based single system used in the present invention comprises a monomer of an acrylic moiety, which may optionally comprise a hydroxyl group, a halogen, an alkyl group, an epoxy group, and an aromatic moiety in the acrylic moiety and/or the ester moiety. The functional groups of the base and its combination. The acrylate monomer may be, for example, but not limited to, an acrylate, a methacrylate, a hydroxy acrylate, a hydroxy methacrylate or the like; and an ester moiety thereof may be formed from a C _1-12 alkanol, preferably C _{4 The -6} alkanol is formed; the alkyl portion of the alkanol may be substituted with a functional group selected from the group consisting of a hydroxyl group, a halogen group, an alkyl group, an epoxy group, an aryl group, and a combination thereof. Examples of acrylate monomers include, but are not limited to acrylic acid C _1-6 alkyl methacrylate, C _1-6 alkyl acrylates, hydroxy C _1-6 alkyl esters of methacrylic acid and hydroxy-C _1-6 alkyl ester. In the preparation of the styrene-anhydride-acrylate copolymer of the present invention, the acrylate monomer is used in an amount of 5 to 50 mol%, preferably 15 to 40 mol%, most preferably 25 to 35 mol%. .

The styrene-anhydride-acrylate copolymer provided by the present invention forms a side chain having a functional group by subjecting at least a part of the acid anhydride moiety to ring-opening reaction. The functional group may be a group such as a carboxylic acid group, an ester group, or a decylamino group.

The at least 50 mole % of the anhydride portion of the styrene-anhydride-acrylate copolymer provided by the present invention is subjected to a ring opening reaction, such as at least 60 mole %, at least 70 mole %, at least 80 mole %, at least 90 moles The ring opening reaction is carried out at %, preferably at least 95 mol%, more preferably at least 98 mol%.

The carboxylic acid group on the side chain may be derived from a ring-opened anhydride moiety such as a maleic carboxylic acid group, a citraconic acid group, a itaconin carboxylic acid group, a sulphonic acid group, an aconitine carboxylic acid group, a pentene group. Diacid groups, mukic acid groups, and the like.

The ester group on the side chain can be formed by ring-opening reaction of an alkanol or an unsaturated bond-containing alcohol with an acid anhydride moiety. The alkanols or alcohols containing unsaturated bonds may have from 1 to 6 carbon atoms, and the carbon chain moieties may be linear, such as, but not limited to, methanol, ethanol, propanol, isopropanol, butanol, Alcohol, ethylene glycol, propylene glycol, allyl alcohol, etc.; or the carbon chain moiety may comprise a branch, such as, but not limited to, a third butanol, an isobutanol, a 3-methyl-2-ene-1-butanol Wait. Methanol is preferred.

The guanamine group on the side chain can be formed by ring-opening reaction of a secondary amine with an acid anhydride moiety. The secondary amine can be represented by the following formula (I): NR ₁ R ₂ R ₃ (I)

Wherein R ₁ , R ₂ and R ₃ are, independently of each other, hydrogen or C _1-6 alkyl, wherein the -CH ₂ - group of the alkyl group is optionally substituted by N, O or S; or both The atom forms a five or six member saturated or unsaturated heterocyclic ring, and the five or six member saturated or unsaturated heterocyclic ring contains a nitrogen atom (i.e., N in the formula) and an additional one or more selected from the group consisting of The heteroatoms of N, O and S are members of the ring; provided that one of R ₁ , R ₂ and R ₃ is hydrogen and the other two are not hydrogen. Examples include, but are not limited to, diethylamine, dipropylamine, methylethylamine, methylpropylamine, dibutylamine, ethylpropylamine, diamylamine, dihexylamine, ethylbutylamine, pyrrolidine, 2 or 3 -pyrroline,pyrrole,pyrrolidine,pyrazole,imidazole,imidazidine,pyrazolidine,pyrazoline,piperidine,piperidin Hexahydropyridine, hexahydropyridyl And ifolin and so on. Preferred are diethylamine, dipropylamine and dibutylamine.

The present invention also provides a process for preparing an ester group-containing styrene-anhydride-acrylate copolymer, which comprises the steps of: (1) freeing a styrene monomer, a cyclic anhydride monomer, and an acrylate monomer; The base polymerization reaction obtains an unopened styrene-anhydride-acrylate copolymer; (2) the unopened styrene-anhydride-acrylate copolymer obtained in the step (1) and an alkanol, At least one of an unsaturated bond alcohol and a secondary amine performs the ring opening reaction.

The styrene monomer, the cyclic anhydride monomer, the acrylate monomer, the alkanol, the unsaturated bond-containing alcohol, and the secondary amine described in the production method are as described above.

In the step (1), the polymerization reaction is a radical polymerization reaction. The reaction is carried out in a polar solvent such as acetone, methyl ethyl ketone, methylene hydrazine or tetrahydrofuran. The reaction temperature is 70 to 110 ° C, preferably 95 ° C. The reaction time is 6 to 12 hours, preferably 8 hours. The initiator may be (1) an organic peroxide such as dibenzoyl peroxide or dicumyl peroxide. Di(t-butyl) peroxide, dodecyl peroxide, tert-butyl peroxybenzoate, diisopropyl peroxydicarbonate, dicyclohexyl peroxydicarbonate, etc.; (2) A nitrogen compound such as azobisisobutyronitrile or azobisisoheptanenitrile.

In the step (2), the ring-opening reaction is carried out in a polar solvent, and the solvent is preferably acetone, methyl ethyl ketone, methylene hydrazine or tetrahydrofuran. The reaction temperature is 70 to 100 ° C, preferably 90 ° C. The reaction time is 2 to 8 hours, preferably 4 to 6 hours. The ring-opening reaction can be carried out using an alcohol and a secondary amine separately or simultaneously.

The present invention also provides a photosensitive resin composition comprising (a) at least one styrene-anhydride-acrylate copolymer of the present invention, (b) a photopolymerization initiator, (c) a photopolymerizable monomer, (d) a solvent and (e) a selective additive. The resin composition may optionally comprise a conventionally known resin such as (1) a methacrylic acid-methyl methacrylate copolymer, (2) a styrene and maleic anhydride monoester copolymer, and (3) a carboxylic acid group. Epoxy acrylic resin, and the like.

In the photosensitive resin composition of the present invention, the content of the component (a) styrene-anhydride-acrylate copolymer is from 10 to 70% by weight, preferably from 30 to 50% by weight.

In the photosensitive resin composition provided by the present invention, the component (b) photopolymerization initiator used forms a radical form by absorbing light energy, and provides a radical required for polymerization of the photoreactive monomer. Examples are 2,2'-bis(2-chlorophenyl)-4,4'-5,5'-tetraphenylbisimidazole, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy- 1,2-diphenylethyl-1-one, 2,2-dimethoxy-1,2-diphenylethan-1-one, 2-methyl-1-[4-(methylthio)phenyl]- 2- N - morpholino-propan-1-one (2-methyl-1- [4- (methylthio) phenyl] -2-morpholino propan-1-one), 2- benzyl-2-dimethylamine group -1- [4- N - morpholinyl phenyl] butan-1-one (2-benzyl-2-dimethylamino -1- [4-morpholinopheyl] butan-1-one), 2- hydroxy-2- 2-hydroxy-2-methyl-1-phenyl propan-1-one, 2,4,6-trimethylbenzimidyldiphenylphosphine oxide (2 ,4,6-trimethyl benzoyl diphenyl phosphine oxide), 1-[4-(2-hydroxymethoxy)phenyl]-2-hydroxy-2-methylpropan-1-one (1-[4-(2) - hydroxymethoxy)phenyl]-2-hydroxy-2-methyl propan-1-one), 2,4-diethylthioxanetone, 2-chlorothioxantone ), 2,4-dimethylthioxantone, 3,3-dimethyl-4-methoxybenzophenone, phenyl ketone, 1-chloro-4-propoxy Thiopinone, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1- (1-(4-isopropyl phenyl)-2-hydroxy-2-methyl propan-1-one), (1-(4-dodecylphenyl)-2-hydroxy-2-methylpropan-1- Ketone (1-(4-dodecyl phenyl)-2-hydroxy-2-methyl propan-1-one), 4-benzylidene-4'-methyldimethyl sulfide (4-benzoyl-4'-methyl Dimethylsulfide), 4-dimethylaminobenzoic acid, methyl 4-(dimethylamino)benzoate, ethyl 4-(dimethylamino)benzoate, 4-(dimethylamino)benzene Butyl formate, 2-ethylhexyl 4-methylhexyl benzoate, 2-isoamyl 4-dimethylaminobenzoate, 2,2-diethoxyacetophenone, benzyl ketone dimethyl acetal (benzyl ketone dimethyl acetal), benzyl ketone β - methoxy diethyl acetal (benzyl ketone β-diethyl acetal) , 1- phenyl-1,2-propyl dioxime -o, O'-(2-carbonyl)ethoxy ether (1-phenyl-1,2-propyl dioxime-o,o'-(2-carbonyl)ethoxyether), o-benzidine benzoic acid methyl ester, double (4- Bis(4-dimethylamino phenyl)ketone, 4,4'-bis(diethylamino)benzophenone, 4,4'-dichlorobenzophenone, benzene Benzyl, benzoin, methoxybenzoin, ethoxybenzoin, isopropoxy benzoin, n-butyl Kean, isobutoxybenzoin, tert-butoxybenzoin, p-dimethylaminoacetophenone, p-tert-butyltrichloroacetophenone, p-tert-butyldichloroacetophenone, thia Anthrone, 2-methylthiazepinone, 2-isopropylthioxanthone, dibenzocycloheptanone, a, a-dichloro-4-phenoxyacetophenone, pentyl-4- Dimethylaminobenzoate. Preferred is 2-methyl-1-[(4-methylthiophenyl)]-2-(4- N -morpholinyl)-1-propanone and 2-isopropylthioxanthone. The content is from 0.01 to 10% by weight, preferably from 0.5 to 5% by weight.

In the photosensitive resin composition provided by the present invention, the component (c) used as a photopolymerizable monomer is a monomer having an unsaturated double bond, and undergoes radical chain polymerization upon exposure. Examples are polyfunctional (meth)propionate monomers such as tri-propylene glycol diacrylate (tripropylene glycol diacrylate), ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, propylene glycol Propylene glycol dimethacrylate, polypropylene glycol dimethacrylate, butylene glycol dimethacrylate, neopentyl glycol dimethacrylate (neopentyl glycol) Dimethacrylate), 1,6-hexane glycol dimethacrylate, trimethyolpropane trimethacrylate, trimethyolpropane Triacrylate), pentaerythritol triacrylate, pentaerythritol teraacrylate, glycerin dimethacrylate, neopentyl alcohol dimethacrylate Pentaerythritol dimethacrylate), pentaerythritol trimethacrylate Pentaerythritol trimethacrylate, dipentaerythritol pentamethacrylate, 2,2-bis(4-methylpropenyloxydiethoxyphenyl)propane (2,2-bis (4-methacryloxydiethoxyphenyl)propane), trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, ethoxylated bisphenol A diacrylate), ethoxylated bisphenol A dimethacrylate, 2,2-bis(4-methylpropenyloxypolyethoxyphenyl)propane (2,2- Bis(4-methacryloxypolyethoxyphenyl)propane), 2-hydroxy-3-methacryloyloxypropyl methacrylate, polyfunctional polyurethane acrylate, and the like. Preferred are tri- and tetra-functional (meth) acrylate monomers. The photopolymerizable monomer content is from 1 to 20% by weight, preferably from 5 to 15% by weight.

In the photosensitive resin composition provided by the present invention, the (d) solvent used may be a polar solvent such as acetone, methyl ethyl ketone, tetrahydrofuran or monomethyl ether propylene glycol acetate; or may be a nonpolar solvent such as toluene. The solvent contained in the composition is preferably monomethyl ether propylene glycol acetate. The solvent content is adjusted depending on the content of the photopolymerization initiator, the basic development binder, the photopolymerizable monomer, and the selective additive.

The (e) additive which does not impair the properties of the photosensitive resin composition of the present invention can be selectively added. The additive may be a plasticizer such as a phthalate, including, but not limited to, dibutyl phthalate, diheptyl phthalate, dioctyl phthalate, phthalic acid. Diallyl ester or the like; ethylene glycol esters, including but not limited to triethylene glycol diacetate, tetraethylene glycol diacetate, etc.; guanamines, including but not limited to p-toluenesulfonamide, benzenesulfonate Indoleamine, n-butylbenzenesulfonamide, etc.; and triphenyl phosphate.

The additive may also be a coloring matter such as toluenesulfonic acid monohydrate, basic fuchsin, phthalocyanine green, auramine, by-product magenta, crystal violet, methyl orange, Nero blue 2B, Victoria blue, malachite green, King Kong green, alkaline blue. The content is from 0.001 to 5% by weight, preferably from 0.01 to 1% by weight.

Figure 1 is an IR spectrum of an unopened styrene-maleic anhydride-butyl methacrylate copolymer.

Figure 2 is an IR spectrum of a styrene-maleic anhydride-acrylate copolymer of the present invention.

The present invention is further clarified by the following examples, which are not intended to limit the scope of the invention as claimed.

Example 1: Synthesis of unopened styrene-maleic anhydride-acrylate copolymer

The molar ratio of styrene, maleic anhydride and butyl methacrylate is 2:1:1, wherein 112.99g of styrene, 53.19g of maleic anhydride and 77.13g of butyl methacrylate; the initiator is Azobisisobutyronitrile 0.85 g; medium was 373 ml of butanone. First, 37.66 g of styrene, 17.73 g of maleic anhydride, 25.71 g of butyl methacrylate, and 37.2 of 7 ml of methyl ethyl ketone were placed in a 1000 ml high pressure reaction vessel equipped with a stir bar to dissolve by heating. 0.85 g of azobisisobutyronitrile was dissolved in 298.46 ml of methyl ethyl ketone, and then placed in a dispenser to drip the raw material. The remaining 75.33 g of styrene, 35.46 g of maleic anhydride, and 51.42 g of butyl methacrylate were dissolved in 37.27 ml of methyl ethyl ketone, and then placed in a dispenser for dropwise addition of the starting material. The reaction was carried out at a polymerization temperature of 95 ° C for 8 hours to obtain a transparent colorless unopened styrene-maleic anhydride-butyl methacrylate copolymer solution, and the IR spectrum was as shown in FIG. The solid content of the product was measured to be 41.3% and the solid content acid value was 247.49 mg KOH/g.

Example 2: Preparation of the styrene-maleic anhydride-acrylate copolymer of the present invention

The unopened styrene-maleic anhydride-butyl methacrylate copolymer (100 g) synthesized in Example 1 and methanol (11.8 g) were added to a high pressure reaction vessel, and reacted at 90 ° C for 6 hours to obtain the present invention. The styrene-maleic anhydride-methacrylate copolymer, IR spectrum is shown in Figure 2. From this spectrum it is shown that the anhydride functional group is nearly 100% open-loop. The solid content of the product was measured to be 41.32% and the solid content acid value was 150.65 mg KOH/g.

The IR spectrum of the ring-opened modified styrene-maleic anhydride-butyl methacrylate copolymer was measured. As shown in Fig. 2, a characteristic peak of maleic anhydride was not exhibited between 1800 cm ^-1 and 2800 cm ^-1 , indicating that the maleic anhydride had substantially completely subjected to a ring-opening reaction.

Example 3: Preparation of Photosensitive Resin Composition of the Present Invention

As shown in Table 1, the photosensitive resin compositions of the present invention and comparative examples were prepared and the properties measured were as follows:

The composition was applied to a copper foil substrate, baked, and the solvent was removed, exposed to ultraviolet light at 100 mj/cm ² , and developed with 1% Na ₂ CO _{3 for} 45 seconds. The method for determining each property is as follows: Sensitivity: The photohardenability is tested with a Stouffer 21 step negative film, and the higher the number of cells, the better. Post-imaging resolution: Test the resolution with line negatives. The smaller the value, the better. Attachment ability after development: Test the adhesion ability with the line film. The smaller the value, the better. Film removal ability: The time of peeling can be immersed in a 3% aqueous solution of NaOH at 50 ° C. The shorter the time, the better. Acid resistance: After immersing in 6N HCl aqueous solution for 1 minute, the smaller the adhesion value, the better the acid resistance.

As can be seen from the above data, the photosensitive resin composition prepared by the ring-opening modified styrene-maleic anhydride-acrylate copolymer exhibits better fine line adhesion, development resolution, and go compared with the known copolymer. Film speed, acid resistance and other properties.

Claims (24)

A styrene-anhydride-acrylate copolymer composed of a styrene monomer, a cyclic unsaturated acid anhydride monomer, and an acrylate monomer, wherein the anhydride portion formed by the cyclic unsaturated acid anhydride monomer At least a portion of the ring is opened and the side chain comprises at least one functional group of a carboxylic acid group, an ester group, and a guanamine group. The copolymer of claim 1, wherein the styrene system is selected from the group consisting of styrene and methylstyrene monomers, wherein the benzene ring of the styrene monomer is optionally substituted with a substituent. The copolymer of claim 1, wherein the anhydride monosystem is selected from the group consisting of maleic anhydride, citraconic anhydride, itaconic anhydride, cis-aconitic anhydride, ecanoic anhydride, glutaconic anhydride, viscosic anhydride monomers, and combinations thereof. The copolymer of claim 1, wherein the acrylate system is selected from the group consisting of C _1-6 alkyl acrylate, C _1-6 alkyl methacrylate, hydroxy C _1-6 alkyl acrylate, methyl A hydroxy C _1-6 alkyl acrylate monomer and combinations thereof. The copolymer of claim 1, wherein the acid anhydride moiety is subjected to the ring-opening reaction with at least one of an alkanol, an unsaturated bond-containing alcohol, and a secondary amine. The copolymer according to claim 5, wherein the alkanol or the unsaturated bond-containing alcohol has 1 to 6 carbon atoms, and the carbon chain is linear or branched. The copolymer of claim 5, wherein the secondary amine has the formula NR ₁ R ₂ R ₃ wherein R ₁ , R ₂ and R ₃ are each independently hydrogen or C _1-6 alkyl, or both Forming a five- or six-membered saturated or unsaturated heterocyclic ring with a N atom, the five or six member saturated or unsaturated heterocyclic ring containing a nitrogen atom and optionally one or more additional selected from the group consisting of N, O and S A hetero atom is a member of the ring; provided that one of R ₁ , R ₂ and R ₃ is hydrogen and the other two are not hydrogen. The copolymer of claim 1 wherein the anhydride moiety is at least 50 mole percent by ring opening. A method for producing a copolymer according to any one of claims 1 to 8, which comprises the steps of: (1) subjecting a styrene monomer, a cyclic unsaturated acid anhydride monomer, and an acrylate monomer to radical polymerization Obtaining an unopened styrene-anhydride-acrylate copolymer; (2) obtaining the unopened styrene-anhydride-acrylate copolymer obtained in the step (1) with an alkanol or an unsaturated bond At least one of the alcohol and the secondary amine performs the ring opening reaction. The method of claim 9, wherein the styrene system is selected from the group consisting of styrene and methyl styrene monomers, wherein the benzene ring of the styrene monomer is optionally substituted with a substituent. The method of claim 9, wherein the anhydride is selected from the group consisting of maleic anhydride, citraconic anhydride, itaconic anhydride, cis-aconitic anhydride, trans-aconitic anhydride monomers, and combinations thereof. The method of claim 9, wherein the acrylate system is selected from the group consisting of C _1-6 alkyl acrylate, C _1-6 alkyl methacrylate, hydroxy C _1-6 alkyl acrylate, methacrylic acid Hydroxy C _1-6 alkyl ester monomers and combinations thereof. The method of claim 9, wherein the alkanol or the unsaturated bond-containing alcohol has 1 to 6 carbon atoms, and the carbon chain is linear or branched. The method of claim 9, wherein the secondary amine has the formula NR ₁ R ₂ R ₃ wherein R ₁ , R ₂ and R ₃ are independently of each other hydrogen or C _1-6 alkyl, or both The N atom forms a five or six member saturated or unsaturated ring, the five or six member saturated or unsaturated ring containing a nitrogen atom and optionally one or more additional heteroatoms selected from N, O and S Ring member; provided that one of R ₁ , R ₂ and R ₃ is hydrogen and the other two are not hydrogen. A photosensitive resin composition comprising (a) at least one copolymer according to any one of items 1 to 8, (b) a photopolymerization initiator, (c) a photopolymerizable monomer, (d) a solvent, and (e) ) Selective additives. The photosensitive resin composition of claim 15, wherein the component (a) is contained in an amount of from 10 to 70% by weight. The photosensitive resin composition of claim 15, wherein the component (b) is selected from the group consisting of organic peroxides, azo compounds, and combinations thereof. The photosensitive resin composition of claim 15, wherein the component (b) is contained in an amount of from 2 to 5% by weight. The photosensitive resin composition of claim 15, wherein the component (c) is a polyfunctional (meth)propionate monomer. The photosensitive resin composition of claim 15, wherein the component (c) is contained in an amount of from 8 to 15% by weight. The photosensitive resin composition of claim 15, wherein the component (d) is a polar or non-polar solvent. The photosensitive resin composition of claim 15, wherein the component (d) is contained in an amount of 15 to 35 % by weight. The photosensitive resin composition of claim 15, wherein the component (e) is selected from the group consisting of plasticizers, colorants, and combinations thereof. The photosensitive resin composition of claim 15, wherein the component (e) is contained in an amount of not more than 2% by weight.