Modified epoxy acrylate, photoresist composition and method for producing the same, transparent photoresist

Abstract

The present invention relates to a modified epoxy acrylate and a method for producing the same, a photoresist composition and a method for producing the same, and a transparent photoresist formed from the photoresist composition. The modified epoxy acrylate is an epoxy acrylate modified with phosphate monomer which has a structure represented by Formula I ##STR00001## wherein, n is an integer selected from 1˜21, R is a short-chain carboxylic acid ester group having the structural formula ##STR00002##  in which p is a bivalent saturated or unsaturated carbon chain having 1˜10 carbon atoms, and the carbon chain is optionally substituted by alkyl, alkenyl, hydroxy, nitro or halogen. Since the phosphate can react with the multi-valence metal in substrates so as to connect the polymer onto the substrates firmly through covalent bonds, therefore the adhesion force is improved significantly and the protective function of the tranparent photoresist is improved accordingly.

Claims

1. A modified epoxy acrylate, which is epoxy acrylate modified with phosphate monomers, having the structural formula represented by Formula I ##STR00013## wherein, n is an integer selected from 1˜21, R is a short-chain carboxylic acid ester group having the structural formula ##STR00014##  in which p is a bivalent saturated or unsaturated carbon chain having 1˜10 carbon atoms, and the carbon chain is optionally substituted by alkyl, alkenyl, hydroxy, nitro or halogen.

2. The modified epoxy acrylate according to claim 1, wherein, said epoxy acrylate modified with phosphate monomers has the structural formulas represented by Formula II or Formula III ##STR00015## wherein, n is an integer selected from 1˜21.

3. A photoresist composition, comprising: 30˜50 parts by weight of the epoxy acrylate modified with phosphate monomers represented by Formula I; 10˜20 parts by weight of aliphatic polyurethane acrylate resin; 20˜30 parts by weight of active monomers; 5˜10 parts by weight of active diluent agents; 2˜5 parts by weight of photoinitiators; 30˜35 parts by weight of organic solvents, ##STR00016## wherein, n is an integer selected from 1˜21, R is a short-chain carboxylic acid ester group having the structural formula ##STR00017##  in which p is a bivalent saturated or unsaturated carbon chain having 1˜10 carbon atoms, and the carbon chain is optionally substituted by alkyl, alkenyl, hydroxy, nitro or halogen; wherein said active monomers consist of low functionality monomer, alkyl chain-acrylates, and high functionality monomer; said low functionality monomer is cyclohexane-1,4-dimethanol divinylether or triglycol divinyl ether; the high functionality monomer is ethoxylated pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, or dipentaerythritol hexaacrylate; and wherein the active diluent agent consists of one or more of allyl glycidyl ether, glycidyl phenyl ether, glycol diglycidyl ether and ricinus oil tryglycidyl ether.

4. The photoresist composition according to claim 3, wherein, said epoxy acrylate modified with phosphate monomer is in the range of 40˜48 parts by weight; the aliphatic polyurethane acrylate resin is in the range of 12˜15 parts by weight; the active monomer is in the range of 20˜25 parts by weight; the active diluent agent is in the range of 5˜8 parts by weight; the photoinitiator is in the range of 3˜4 parts by weight; the organic solvent is in the range of 32˜34 parts by weight.

5. The photoresist composition according to claim 3, wherein, said active monomer consist of low functionality monomer, alkyl chain-acrylates, and high functionality monomer in a range of 1:0.5˜1:1.5˜6 by mass ratio.

6. The photoresist composition according to claim 5, wherein the alkyl chain-acrylates include Glycol dimethacrylate or Triethylene glycol di-2-methyl acrylate.

7. The photoresist composition according to claim 3, wherein the photoinitiator includes cyanine dye cation complexes, triphenyl-alkyl boron anion complexes and aromatic iodonium salts; and the organic solvent includes aliphatic organic solvents.

8. The photoresist composition according to claim 3, wherein said photoresist composition further includes 3˜5 parts by weight of fillers, and 1˜2 parts by weight of additives selected from the group consisting of anti-foaming agents, dispersing agents, leveling agents, and mixtures thereof.

9. The photoresist composition according to claim 8, wherein, said filler includes polyamide wax suspensions.

10. A transparent photoresist obtained from a photoresist composition according to claim 3.

11. A method for producing a modified epoxy acrylate represented by Formula I, comprising: Performing a polymerization of 2-hydroxyethyl methacrylate phosphate and epoxy compound represented by formula IV in the presence of a basic catalyst, to obtain the epoxy acrylate modified with phosphate monomers represented by formula I, wherein, the molar ratio of the 2-hydroxyethyl methacrylate phosphate to the epoxy compound is 1:0.5˜10; the reaction formula being as follows: ##STR00018## wherein, n is an integer selected from 1˜21, R is a short-chain carboxylic acid ester group having the structural formula ##STR00019##  in which p is a bivalent saturated or unsaturated carbon chain having 1˜10 carbon atoms, and the carbon chain is optionally substituted by alkyl, alkenyl, hydroxy, nitro or halogen.

12. A method for producing a photoresist composition according to claim 3, wherein the method comprises: taking and mixing the epoxy acrylate modified with phosphate monomers, aliphatic polyurethane acrylate resins, active monomers, active diluent agents and photoinitiators according to the respective parts by weight, to obtain a mixture; performing a sand grinding treatment of the above mixture, to form a mixture with a micron level fineness; adjusting the viscosity of the mixture with a micron level fineness with organic solvents.

Description

EXAMPLES

(1) The following examples specifically describe the epoxy acrylate modified with phosphate monomers of the present invention and the method for producing the same, the photoresist composition and the method for producing the same. However, the present invention is not limited to the following examples. It should be noted that, unless specified otherwise, the respective constituents in the photoresist composition is represented in “parts by weight”.

Example 1

Preparation of 3,4-epoxycyclohexylmethyl3′,4′-epoxycyclohexyl Formate Modified with 2-hydroxyethyl methacrylate phosphate (Preparation of Formula II):

(2) 100 g of the epoxy compound (i.e. 3,4-epoxycyclohexylmethyl 3′,4′-epoxycyclohexyl formate, 0.294 mol) and 500 ml of the mixed solvents of proprylene glycol monomethyl ether and n-butanol are added into a 1000 ml flask and heated to 100° C.; after the dissolution of the epoxy compound, 125.3 g of 2-hydroxyethyl methacrylate phosphate (which is dissolved in 100 ml proprylene glycol monomethyl ether) is added dropwise, and then 1 g of hydroquinone as polymerization inhibitor and 10 g of tertiary amine catalyst are added therein. The reactant mixture is heated to 130° C. and kept for 3 hours. The obtained product is cooled and the solvent is removed by filtration to obtain the epoxy acrylate modified with 2-hydroxyethyl methacrylate phosphate. The product is identified by nuclear magnetic resonance (NMR): before the reaction, the chemical shift of the hydrogen atoms linked to the two carbons of the epoxy group of the epoxy compound is (δ: 3.05, 2.68, 2.35); while after the reaction, the hydrogen atoms of the corresponding two carbon atoms has a chemical shift of (δ: 4.03, 3.65, 3.37) since the epoxy group is disappeared from the epoxy compound after reaction.

(3) The synthesis route of the above reaction is:

(4) ##STR00011##

(5) The product has a weight-average molecular weight in a range of 1500-3900 (measured by Gel permeation chromatography (GPC) with THF as the eluent).

Example 2

Preparation of bis[(3,4-epoxycyclohexyl)methyl]adipate Modified with 2-hydroxyethyl methacrylate phosphate (Preparation of Formula III):

(6) 100 g of the epoxy compound (hence, bis[(3,4-epoxycyclohexyl)methyl]adipate (0.231 mol)), and 500 ml of the mixed solvents of proprylene glycol monomethyl ether and n-butanol are added into a 500 ml flask, increasing the temperature to 120° C.; after the dissolution of the epoxy compound, 148 g 2-hydroxyethyl methacrylate phosphate (which is dissolved in 100 ml proprylene glycol monomethyl ether) is added dropwise, and then 1.5 g benzenediol inhibitor and 15 g tertiary amine-type catalyst is added; the reactant mixture is heated to 140° C. and kept for 5 hours, and the resultant is cooled and filtered to give bis[(3,4-epoxycyclohexyl)methyl]adipate modified with 2-hydroxyethyl methacrylate phosphate (Formula III). The reaction product is identified by nuclear magnetic resonance (NMR): the chemical shift of the hydrogen atoms linked to the two carbons of the epoxy group of the epoxy compound before the reaction is (δ: 3.05, 2.81, 4.75), while the corresponding hydrogen atoms of the two carbon atoms has a chemical shift of (δ: 4.06, 3.83, 5.87), since the epoxy group is disappeared from the epoxy compound after reaction.

(7) The synthesis route of the above reaction is:

(8) ##STR00012##

(9) The product has a weight-average molecular weight in a range of 1800-4900 (measured by Gel permeation chromatography (GPC) with THF as the eluent).

Preparation of the Photoresist Composition and the Transparent Photoresist (i.e. the Cured Film)

(10) Photoresist composition 1˜4 are prepared by employing the epoxy acrylates modified with phosphate monomers obtained from Example 1 and Example 2 as well as other constituents of the photoresist composition.

(11) Unless noted otherwise, the fineness of the composition was measured according to the following method: the composition to be measured is diluted for 10 folds firstly, and then the diluted composition was measured by a Malvern particle size analyzer (NaNo ZS, manufactured by Malvern Co. Ltd).

(12) Unless noted otherwise, the viscosity of the composition is measured by DV-C digital viscometer (manufactured by Brookfield Co. Ltd, USA).

Example 3

Preparation of Photoresist Composition 1

(13) 30 parts of the epoxy acrylate modified with phosphate monomer represented by Formula II, 20 parts of the polyurethane acrylate (7200, Jiangmen Hengguang New Materials Co., Ltd), 4 parts of 1,4-cyclohexanedimethanol divinyl ether (Shanghai Polydex Industry Co., Ltd), 4 parts of Ethyleneglycol dimetharcylate (Shanghai Chunall International Trade Co., Ltd) and 12 parts of Dipentaerythritol pentaacrylate (Shanghai Richness Chemical Co., Ltd), 5 parts of ricinus oil triglycidyl ether as the diluent agent (Shenzhen Jiada Chemical Engineering Co., Ltd), 3 parts of fillers (polyamine wax, Kunshan superfine materials of tangible elements Co., Ltd; silica, Shouguang Baote Chemical Co., Ltd; and mica, Shenzhen Haiyang Powder Technology Co., Ltd), 3 parts of cyanine dye cation complexes photoinitiator, 0.5 parts of anti-foaming agents (BYK-075, BYK Additives & Instruments, Germany), 0.6 parts of leveling agents (BYK-354, BYK Additives & Instruments, Germany), 32 parts of propylene glycol diacetate (Shanghai Yanshou Chemical Engineering Co., Ltd) as the organic solvent are homogenously mixed by the Ultrasonic process (frequency 25 KHz, time 30 min), followed by sand milling with a sand miller. The resultant mixture has a fineness of 7 μm, and then 2 parts of methyl methacrylate (Jinan Yuanyang Chemical Engineering Co., Ltd) is added to adjust the viscosity to 150 cps measured at 25° C., so as to obtain the photoresist composition 1.

Example 4

Preparation of Photoresist Composition 2

(14) 48 parts of the epoxy acrylate modified with phosphate monomer represented by Formula III, 12 parts of the polyurethane acrylate, 6 parts of triglycol divinyl ether (GuangZhou Sunlake Trading Co., Ltd), 3 parts of Ethyleneglycol dimetharcylate and 9 parts of Dipentaerythritol pentaacrylate, 4 parts of glycol diglycidyl ether as the diluent agent (Changzhou Hongyu Chemical Co., Ltd), 4 parts of fillers (polyamine wax; silica; and mica), 3.5 parts of aromatic iodonium salt photoinitiator (Shanghai Fanke Co., Ltd), 0.6 parts of anti-foaming agents (BYK-355, BYK Additives & Instruments, Germany), 0.5 parts of leveling agents (BYK-380, BYK Additives & Instruments, Germany), 33 parts of 2-Methyl-3-heptanone (Haorui Chemistry (Shanghai) Co., Ltd) as the organic solvent are homogenously mixed by the Ultrasonic process (frequency 25 KHz, time 35 min), followed by sand milling with a sand miller. The resultant mixture has a fineness of 5 μm, and then 2 parts of allyl glycidyl ether (Jinan TianQiao XianKe Chemical product department) is added to adjust the viscosity to 200 cps measured at 25° C., so as to obtain the photoresist composition 2.

Example 5

Preparation of Photoresist Composition 3

(15) 50 parts of the epoxy acrylate modified with phosphate monomer represented by Formula II, 10 parts of the polyurethane acrylate, 6 parts of 1,4-cyclohexanedimethanol divinyl ether, 6 parts of Ethyleneglycol dimetharcylate and 18 parts of ethoxylated pentaerythritol tetracrylate (Shanghai Chunall International Trade Co., Ltd), 3 parts of glycol diglycidyl ether as the diluent agent, 4 parts of triphenyl-alkyl boron anion complexes photoinitiator, 0.8 parts of anti-foaming agents (BYK-355, BYK Additives & Instruments, Germany), 0.7 parts of leveling agents (BYK-358, BYK Additives & Instruments, Germany), 30 parts of cyclohexanone (Jinan Lianying Chemical Co., Ltd) as the organic solvent are homogenously mixed by the Ultrasonic process (frequency 25 KHz, time 35 min), followed by sand milling with a sand miller. The resultant mixture has a fineness of 6 pm, and then 2 parts of allyl glycidyl ether is added to adjust the viscosity to 180 cps measured at 25° C., so as to obtain the photoresist composition 3.

Example 6

Preparation of Photoresist Composition 4

(16) 40 parts of the epoxy acrylate modified with phosphate monomer represented by Formula III, 15 parts of the polyurethane acrylate, 4.3 parts of 1,4-cyclohexanedimethanol divinyl ether, 3.4 parts of ethyleneglycol dimetharcylate and 17.3 parts of dipentaerythritol hexaacrylate (Shanghai Richness Chemical Co., Ltd), 6 parts of allyl glycidyl ether as the diluent agent, 2.5 parts of cyanine dye cation complexes, 1.5 parts of triphenyl-alkyl boron anion complexes photoinitiator, 0.6 parts of anti-foaming agents (BYK-325, BYK Additives & Instruments, Germany), 0.8 parts of leveling agents (BYK-390 BYK Additives & Instruments, Germany), 35 parts of ethyl 3-ethoxypropionate (Dow Chemical, America) as the organic solvent are homogenously mixed by the Ultrasonic process (frequency 25 KHz, time 40 min), followed by sand milling with a sand miller. The resultant mixture has a fineness of 8 μm, and then 2 parts of glycol diglycidyl ether is added to adjust the viscosity to 130 cps measured at 25° C., so as to obtain the photoresist composition 4.

Comparative Example 1

Preparation of photoresist composition 5

(17) 10 parts of phenolic epoxy acrylate 5327 (Tianjin Haiyinci Co., Ltd.), 4 parts of 1,4-cyclohexanedimethanol divinyl ether, 12 parts of Dipentaerythritol pentaacrylate and 5 parts of ricinus oil triglycidyl ether as the diluent agent, 3 parts of fillers (polyamine wax, silica and mica), 3.5 parts of aromatic iodonium salt photoinitiator, 0.5 parts of anti-foaming agents, 0.5 parts of leveling agents, 35 parts of Propylene glycol diacetate as the organic solvent are homogenously mixed by the Ultrasonic process (frequency 25 KHz, time 30 min), followed by sand milling with a sand miller. The resultant mixture has a fineness of 7 μm, and then 2 parts of methyl methacrylate is added to adjust the viscosity to 150 cps measured at 25° C., so as to obtain the photoresist composition 5.

Comparative Example 2

Preparation of Photoresist Composition 6

(18) 60 parts of epoxy methyl acrylate, 3 parts of triethylene glycol di-2-methyl acrylate, 9 parts of dipentaerythritol hexaacrylate and 4 parts of allyl glycidyl ether as the diluent agent, 3 parts of fillers (polyamine wax, silica and mica), 4 parts of cyanine dye cation complexes photoinitiator, 0.6 parts of anti-foaming agents, 0.5 parts of leveling agents, 35 parts of ethyl 3-ethoxypropionate as the organic solvent are homogenously mixed by the Ultrasonic process (frequency 25 KHz, time 30 min), followed by sand milling with a sand miller. The resultant mixture has a fineness of 5 μm, and then 2 parts of methyl methacrylate is added to adjust the viscosity to 200 cps measured at 25° C., so as to obtain the photoresist composition 6.

(19) Transparent photoresist 1˜6 are obtained from photoresist composition 1˜6 by the following method: applying the above photoresist composition 1˜6 by spin coating to a pre-determined thickness on the flexible wiring board or the transparent electrode on which a circuit has been formed by etching the copper foil. Pre-baking for about 10 min at 80° C., and irradiating to perform exposure with the ultraviolet light of 345 nm (10 mJ/cm.sup.2), the exposed portion is removed with diluted alkaline water (KOH diluted solution), to thereby obtain the solder resist or transparent protective film (hence, transparent photoresist 1˜6) with the image as required. The film has a thickness of about 20 μm.

(20) Evaluation of the Properties of the Film

(21) Yellowing Resistance: applying the above photoresist compositions 1˜6 onto the surface of a flexible wiring board respectively, and then performing light irradiation for 200h and observing the degree of color changing.

(22) Adhesion Force Test: 100 small grids of 1 mm×1 mm are formed on the surface of the transparent photoresists 1˜6 using a sharp blade, wherein the cutting edge is 15-30 degrees and every scratch line should reach as deep as the film. The region to be tested is cleaned with a brush, and the grids to be tested are adhered intimately with a tape (3M 610) having an adhesion force of 0.47N/mm for 3 minutes. Then both ends of the tape are hold and pulled instantaneously off the tape in a direction perpendicular to the surface of the tape. Such process including adhesion and pulling off is repeated once more. The transparent photoresist on which the ratio of the falling off area/entire area <5% is evaluated as “Qualified”.

(23) Folding Resistance: the transparent photoresists 1˜6 are repeatedly folded for 180 degrees, and the number of repeat is recorded when the transparent photoresist is broken by observing with naked eyes and an optical metallographic microscope (400×, Nikon Eclipse ME600, Hitachi Co., Ltd).

(24) Total Light Transmittance: the transparent photoresists 1˜6 are prepared on the surface of transparent electrodes respectively, and then measure the total light transmittance in the range of visible spectrum using a colorimeter (LCF-100M, OTSUKA Electronics Co., Ltd).

(25) Insulation Resistance: the photoresist compositions 1˜6 are applied onto flexible wiring boards to obtain solder resist films (i.e, transparent photoresists 1˜6) by exposure and developing. The insulation resistances thereof are measured under Direct Current (DC) of 50V by M12123 Insulation Resistance Analyzer (Chengdu Fuke Instruments Co. Ltd) after being humidified at 40° C. and 90% R.H. for 168 h.

(26) Resolution: the photoresist compositions 1˜6 are applied onto silica glasses respectively. The photoresist compositions are pre-baked and exposed in the present of photomask plate (line width of 3˜80 μm), and then they are developed to obtain line-type transparent photoresists 1˜6. The width of the residual lines and the falling of lines are measured by an optical metallographic microscope (400×, Nikon Eclipse ME600, Hitachi Co., Ltd).

(27) Oil Resistance: after wetting the surfaces of the transparent photoresist 1˜6 with 98% industrial alcohol (ethanol) for 10 min, the surfaces are manually wiped with a force of 500 g/cm.sup.2 for 500 times. The transparent photoresist with no falling off and no base material exposure is evaluated as “qualified”.

(28) Acid and Alkaline Resistance test: 19.9 g of NaCl, 17.5 g of ammonia chloride, 5 g of CO(NH2)2, and 2.5 g acetic acid and 15 g of lactic acid (C3H6O3) are dissolved into fresh distilled water and stirred until complete dissolution, and then NaOH is added to adjust the pH value to 4.2 or 8.8, so as to prepare synthetic perspiration. A piece of gauze is sufficiently impregnated with the synthetic perspiration and then is wrapped on the surfaces of the transparent photoresists 1˜6 respectively with ensuring the sufficient contact between the surface of gauze and the surface of the transparent photoresists 1˜6 followed by being kept in the testing environment (2° C.) for 24 hours. The transparent photoresist with no obvious change (for example, no falling-off or foaming) on the tested surface is evaluated as qualified.

(29) Environmental Resistance Test: the transparent photoresists 1˜6 undergo high temperature of 60° C. and a low temperature of −40° C. for 12 hours respectively. The transparent photoresist with no obvious appearance change (for example, no falling-off or cracking) is evaluated as “qualified”.

(30) The test results of the photoresist compositions 1˜6 is shown in table 1.

(31) TABLE-US-00001 TABLE 1 Acid and Yellowing Adhesion Folding Total light insulation oil alkaline Environmental Test result resistance force resistance transmittance resistance resolution resistance resistance resistance Example1 No 99/100 Crack 96% 2.8 × 10.sup.12 10 μm qualified qualified qualified yellowing after 10 Ω cycles Example2 No 98/100 crack 97% 2.7 × 10.sup.12 10 μm qualified qualified qualified yellowing after 12 Ω cycles Example3 No 98/100 crack 98% 3.0 × 10.sup.12  7 μm qualified qualified qualified yellowing after 15 Ω cycles Example4 No 97/100 crack 97% 3.1 × 10.sup.12  7 μm qualified qualified qualified yellowing after 14 Ω cycles Com. Yellowing 90/100 crack 93% 2.1 × 10.sup.12 20 μm not qualified not Example1 after 7 Ω qualified qualified cycles Com. Yellowing 88/100 crack 92% 2.2 × 10.sup.12 25 μm qualified not qualified Example2 after 5 Ω qualified cycles

(32) It can be seen from the results as shown in table 1, the photo-curing transparent resin according to the present invention is excellent in yellowing resistance, adhesion property and light transmittance. The yellowing resistance is excellent since the aliphatic polyurethane acrylate is used. The epoxy acrylate modified with phosphate monomer is used so that the phosphate can react with the multi-valence metal in substrates, thereby connecting the polymer onto the substrates firmly through covalent bond; therefore the adhesion force is excellent. The folding resistance, oil resistance and the acid and alkaline resistance as well as the environmental resistance (both the high temperature and the low temperature) of the cured film is improved as a result of the use of the low functionality monomer and the high functionality monomer in combination. Therefore, the transparent photoresist formed from the photoresist composition of the present invention has the above excellent properties, to enable the use for the solder resist or the transparent electrode protective film.

(33) It is understood that the present invention is not limited to the above-illustrated embodiments, which were chosen and described in order to best explain the principles of the invention. Those skilled in the art can make various modifications or variations without departing from the spirit and essence of the present invention. It is intended that the scope of the invention be defined by the following claims and their equivalents.