WO2016082304A1

WO2016082304A1 - Photo-cured solder-resist ink

Info

Publication number: WO2016082304A1
Application number: PCT/CN2015/000825
Authority: WO
Inventors: 赵文超; 王辰龙
Original assignee: 北京英力科技发展有限公司
Priority date: 2014-11-28
Filing date: 2015-11-27
Publication date: 2016-06-02

Abstract

A photo-cured solder-resist ink comprises: (A) 100 parts by weight of alkali-soluble resin, (B) 10 to 50 parts by weight of at least one cyclopentanedione oxime ester photoinitiator compound represented by formula (I), (C) 40 to 200 parts by weight of a compound with molecules having ethylenically unsaturated groups, and (D) 2 to 50 parts by weight of pigment.

Description

Light curing solder resist ink

Technical field

The invention relates to a composition of a photocurable solder resist ink and a method for forming a solder resist film. After the photocurable composition is applied onto a substrate and dried, the dried coating film is irradiated with ultraviolet light through a mask. A solder resist pattern is formed by development with an alkaline aqueous solution.

Background technique

In the printed wiring board, electronic components are mounted on the land of the printed circuit substrate on which the conductive circuit pattern is formed in advance, and all circuit regions outside the land are covered by the solder resist film as a permanent protective film. Thus, when the electronic component is soldered to the printed circuit board, the solder can be prevented from sticking to the area not covered by the solder, and the conductor constituting the circuit pattern is prevented from being oxidized by direct exposure to the air.

At present, more applications in solder mask are photocurable solder resist inks. The photocurable solder resist ink is generally used by first baking the coating layer at a lower temperature to volatilize the solvent, pre-curing it by ultraviolet light irradiation, and then developing it through a dilute alkaline aqueous solution to form a pattern. The coating film is subjected to high-temperature heat curing to finally form a solder resist film.

Photoinitiators commonly used in existing solder mask inks such as 907, DETX, IRGACURE OXE02 or combinations thereof are still lacking in pattern size accuracy and pattern edge uniformity and need to be improved.

Summary of the invention

It is an object of the present invention to provide a photocurable solder resist ink which is exposed and developed after coating to obtain a solder resist film having a more precise pattern size and a more uniform pattern edge.

The photocurable solder resist ink of the present invention comprises:

(A) alkali soluble resin

(B) Photoinitiator

(C) a compound having an ethylenically unsaturated group in a molecule

(D) pigment,

Further, it may contain (E) a solvent and a non-characteristic conventional component such as (F) a surfactant and (G) a filler.

The alkali-soluble resin is a resin having a certain acid value, and the acid value is generally in the range of 30 to 300 mg/g KOH, and the weight average molecular weight is in the range of 2,000 to 150,000. The parts by mass in the composition are 100 parts.

Preparation of an alkali-soluble resin: 180 g of benzyl methacrylate, 60 g of methacrylic acid, 60 g of hydroxyethyl methacrylate, 15 g of azobisisobutyronitrile, 6 g of dodecyl mercaptan and 1000 ml of toluene are mixed and placed In a constant pressure dropping funnel; put 1000 ml of toluene into a three-necked flask, install a stirring, constant pressure dropping funnel and a thermometer, turn on the stirring, replace the gas in the flask with nitrogen; heat the flask to bring the solvent temperature to 80-85 ° C, keep warm, start The initiator solution was added dropwise, and the reaction was continued for about 1 hour; the reaction was continued for 6 hours; the cooling was naturally cooled, the stirring was stopped, and after the resin was allowed to settle, the upper clear solution was taken up, the lower solvent-containing resin was filtered, and the resin cake was rinsed with 500 ml of toluene; The filter cake was dried to obtain 250 g of a white powdery solid resin.

The photoinitiator is a key component for absorbing light energy to cause curing of the film layer, and at least one photoactive initiator selected from the group consisting of cyclopentadione oxime ester represented by formula (I) is used.

among them,

Ar ₁ is a substituted ortho-arylene or ortho-heteroaryl group, and the ortho-arylene or ortho-heteroaryl group is bonded to Y ₁ and a carbonyl group by two adjacent atoms to form a ring structure, in addition to R ₁₈ X The substituents on the remaining atoms outside the base are each independently:

a hydrogen atom, a halogen atom, a C ₁ -C ₁₂ alkyl group, a C ₅ -C ₇ cycloalkyl group, a C ₁ -C ₄ alkyl group substituted by a C ₅ -C ₇ cycloalkyl group, a phenyl group, optionally one or more C ₁ -C ₄ alkyl, carboxy, C ₁ -C ₁₂ alkyl acyl, arylcarbonyl, heteroarylcarbonyl, phenyl, halogen atom, CN substituted phenyl, C ₁ -C ₄ alkyl Benzyloxy, R ₁ C(O)O substituted C ₁ -C ₄ alkoxy, C ₁ -C ₃ alkylenedioxy, R ₁ C(O)O, C ₁ -C ₁₂ alkyl sulphide , C ₁ -C ₄ alkylphenylthio, R ₁ C(O)O substituted C ₁ -C ₄ alkylthio, CN, carboxyl, C ₁ -C ₁₂ alkoxycarbonyl, aryl Acyl, heteroaryl formyl, XR ₁₈ ;

Or a ring structure between two adjacent substituents of the above substituent of Ar ₁ or a substituent and Ar ₁ are bonded through a straight bond, a carbon atom or a carbonyl group;

X is O, S or NR ₁₉ ;

Y ₁ is O, S, NR ₂₀ , BR ₂₀ , CR ₁₅ R ₁₆ , SiR ₁₅ R ₁₆ ;

R ₁ is a hydrogen atom, a C ₁ -C ₁₈ alkyl group or a C ₁ -C ₁₈ alkoxy group, optionally substituted by one or more halogen atoms, a C ₁ -C ₄ alkyl group, a C ₅ -C ₇ cycloalkyl group, a hetero Cycloalkyl, phenyl, heteroaryl, CN, C ₁ -C ₄ alkanoyloxy, aroyloxy substituted and/or C ₅ -C ₇ cycloalkylene, phenylene, O, S, NR ₁₇ inserted C ₂ -C ₁₈ alkyl, C ₂ -C ₁₈ alkenyl, optionally substituted by one or more halogen atoms, C ₁ -C ₄ alkyl, C ₅ -C ₇ cycloalkyl, heterocycloalkyl , phenyl, heteroaryl, CN, C ₁ -C ₄ alkanoyloxy, aroyloxy substituted and/or inserted by C ₅ -C ₇ cycloalkylene, phenylene, O, S, NR ₁₇ C ₂ -C ₁₈ alkenyl;

Or R ₁ is C ₅ -C ₇ cycloalkyl, optionally substituted with one or more C ₁ -C ₄ alkyl group, a phenyl group, a halogen atom, CN substituted C ₅ -C ₇ cycloalkyl; or R ₁ is phenyl a phenyl group optionally substituted by one or more C ₁ -C ₄ alkyl groups, a C ₁ -C ₄ alkoxy group, a phenyl group, a halogen atom or a CN; or R ₁ is a naphthyl group; or R ₁ is a benzene group An acyl group, a phenoxycarbonyl group, wherein the phenyl group is optionally substituted by one or two or more halogen atoms, R ₁₇ , C ₅ or C ₆ cycloalkyl, CN, OH, XR ₁₇ ;

R ₁₇ is C ₁ -C ₄ alkyl;

R ₁₈ is a hydrogen atom, a C ₁ -C ₁₈ alkyl group, a C ₁ -C ₄ alkoxyacyl substituted C ₁ -C ₅ alkyl group, a R ₁ C(O)O substituted C ₁ -C ₄ alkyl group, Any one or more halogen atoms, C ₁ -C ₄ alkyl, C ₅ -C ₇ cycloalkyl, heterocycloalkyl, phenyl, heteroaryl, CN, C ₁ -C ₄ alkanoyloxy, Aroyloxy substituted or C ₂ -C ₁₈ alkyl group inserted by C ₅ -C ₇ cycloalkylene, phenylene, O, S, NR ₁₇ ; or R ₁₈ is C ₅ -C ₇ cycloalkyl, Or any C ₅ -C ₇ cycloalkyl substituted by one or more C ₁ -C ₄ alkyl, phenyl, halogen atom, CN; or R ₁₈ is phenyl, optionally by one or more C ₁ -C _C12 alkyl, carboxy, C ₁ -C ₁₂ alkyl group, phenylene, O, S, NR ₁₇ inserted into the C ₂ -C ₁₂ alkyl group, C ₅ -C ₆ cycloalkyl, formyl, C ₅ a C ₆ cycloalkyl substituted C ₂ -C ₄ alkyl acyl group, an aryl carbonyl group, a heteroaryl formyl group, an XR ₁₇ group, a phenyl group, a halogen atom, a CN, a NO ₂ substituted phenyl group;

Or R18 is C1-C4 alkyl acyl, C1-C4 conjugated enoyl, benzoyl, phenoxycarbonyl, wherein phenyl is optionally substituted by one or two or more halogen atoms, R17, C5 or C6 cycloalkyl, CN , OH, XR17 substitution;

Or R18 described above is linked to an aromatic ring in Ar1 or Ar2 by a straight bond, a carbon atom or a carbonyl group to form a new ring.

The cyclopentanone oxime ester photoinitiator represented by the above formula (I) is specifically a compound of the formula (II) or the formula (III).

The photocurable solder resist ink may further contain other commercially available products as co-initiators, for example, selected from the group consisting of α-aminoketones, thioxanthones, acylphosphine oxides, benzophenones, and oxazolidinyl esters. , aryl-1,2-dione-2-oxime ester photoinitiators; specific compounds of these photoinitiators can be:

2-methyl-2-(4-morpholinyl)-1-[4-(methylthio)phenyl]-1-propanone, 2-dimethylamino-2-benzyl-1-(4- Morpholinylphenyl)-1-butanone, 2-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, Bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 4,4'-di(dimethylamino)benzophenone, 9-ethyl-6-(2-methylbenzamide Acyl)carbazole-3-ethanone oxime-O-acetate, 9-ethyl-6-(2-methylbenzoyl)carbazole-3-(3-cyclopentyl)acetone oxime-O- Acetate, 1-(4-phenylthio)phenyl-1,2-octanedione-2-indole-O-benzoate,

The photocurable solder resist ink further contains a component (C), that is, a compound having an ethylenically unsaturated group in the molecule, such as an acrylate compound, and specific examples are neopentyl glycol diacrylate, dipentaerythritol hexaacrylate. Ester, pentaerythritol triacrylate, pentaerythritol tetraacrylate, trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, triethylene glycol Diacrylate, tripropylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, 1,4-butanediol diacrylate and epoxy acrylate.

The components of the photocurable solder resist ink are as follows:

(D) a pigment, such as a pigment such as indigo green, and a pigment dispersion;

(E) a solvent such as propylene glycol methyl ether acetate, dipropylene glycol methyl ether acetate, ethylene glycol ethyl ether acetate, toluene, xylene, tetramethylbenzene, methyl isobutyl ketone, cyclohexanone, ethyl acetate, Butyl acetate, γ-butyrolactone, propylene glycol monomethyl ether, dipropylene glycol diethyl ether, etc.;

(F) a surfactant such as a silicon-containing antifoaming agent, a pigment dispersing agent.

(G) fillers such as barium carbonate, barium sulfate, talc, kaolin, quartz powder, magnesium carbonate, calcium carbonate, aluminum hydroxide, barium titanate, aluminum silicate, calcium silicate, zinc white, titanium dioxide and the like.

The amount of the (A) alkali-soluble resin in the photocurable solder resist ink is 100 parts by mass; (B) the photoinitiator is used in an amount of 10 to 50 parts by mass; (C) the amount of the compound having an ethylenically unsaturated group in the molecule is 40- 200 parts by mass; (D) pigment, in an amount of 2-50 parts by mass.

The other component (E) solvent is used in an amount of from 100 to 300 parts by mass; (F) the surfactant and (G) filler are used in a conventional amount suitable for the application of the composition.

The photocurable solder resist ink is suitably used as a dry coating film having a thickness of 15 to 100 μm. It is also possible to produce a dry film obtained by applying a photocurable solder resist ink to a substrate and then drying it.

The dried coating film is covered with a mask, exposed to ultraviolet light, developed in an alkaline developing solution, and the unexposed portion is washed away to obtain a retained solder resist film.

Ultraviolet light sources are generally high pressure mercury lamps, commonly used with mercury lamps with an emission wavelength of 365 nm or 365 nm light filtered by a grating.

The specific alkaline developing solution is ammonia water, sodium hydroxide solution, potassium hydroxide solution, sodium carbonate solution or potassium carbonate solution, and the unexposed film layer can be dissolved and washed away.

The solder resist film obtained by using the solder resist ink of the present invention has the following advantages: the pattern size is more precise, and the edge of the pattern is more clean and tidy after development.

detailed description

Example 1

1) Solder mask ink preparation:

The components shown in Table 1 were blended with the amounts (parts by mass) shown in Table 1, stirred, mixed, and dispersed to obtain photocurable solder resist ink formulations A-E.

Table 1

2) Solder film formation process:

Each photocurable solder resist ink formulation was screen printed onto the deoxidized copper clad laminate, dried in a hot air circulating drying oven at 75 ° C for 40 min, dried, and then slowly cooled to room temperature, and the line width was fixed on it. A 20 μm and 150 μm line-width pattern photomask was exposed to a front side with a mercury lamp at an exposure of 150 mJ/cm ² , and developed with a 1 wt% Na ₂ CO ₃ aqueous solution at a spray pressure of 0.25 MPa and a temperature of 30 ° C for 90 s. dry.

3) Solder mask performance evaluation:

Edge uniformity evaluation:

The edge uniformity of the pattern pattern was observed with a 100-fold volume microscope. The results are shown in Table 2. The criteria are as follows:

◎The edges are neat, no damage and unnecessary, clear;

○The edges are neat and the edges have a small amount of serrations;

△The edges are less tidy and the edges are more serrated;

×The edges are not neat or the edges are not clear.

Pattern accuracy evaluation

The line width of the developed image was measured by a 100-fold microscopic microscope and compared with the line width of the mask pattern. The results are shown in Table 2. The criteria are as follows:

150μm pattern accuracy evaluation:

◎ image size within ±10% of the mask size;

○ The image size is within ±15% of the mask size;

△ image size within ± 20% of the mask size;

× Image size <mask size -20% or image size> mask size + 20%. 20μm pattern accuracy evaluation:

◎ image size within ± 5% of the mask size;

○ The image size is within ±10% of the mask size;

△ image size within ± 15% of the mask size;

× Image size <mask size - 15% or image size > mask size + 15%.

Table 2

Conclusion: Formulation A and 5-(n-butoxy)indole using 5-(4-isopropylphenylthio)indan-1,2-dione-2-indole-O-acetate- Formulation B of 1,2-diketon-2-indole-O-acetate, edge uniformity and pattern accuracy are optimal.

Example 2

The exposure light source was replaced by a 365 nm LED lamp, and the other processes were the same as in Example 1. The results are shown in Table 3.

table 3

Conclusion: Formulation A and 5-(n-butoxy)indole using 5-(4-isopropylphenylthio)indan-1,2-dione-2-indole-O-acetate- Formulation B of 1,2-dione-2-indole-O-acetate has a better overall effect in the test than formulations C, D, and E.

Claims

A photocurable solder resist ink containing:

(A) an alkali-soluble resin in a weight ratio of 100 parts;

(B) photoinitiator, the weight ratio is 10-50 parts;

(C) a compound having an ethylenically unsaturated group in the molecule, in a weight ratio of 40 to 200 parts;

(D) pigment, the weight ratio is 2-50 parts;

It is characterized in that the photoinitiator (B) contains at least one cyclopentanone oxime ester photoinitiator selected from the formula (I).

among them,

Ar 1 is a substituted ortho-arylene or ortho-heteroaryl group, and the ortho-arylene or ortho-heteroaryl group is bonded to Y 1 and a carbonyl group by two adjacent atoms to form a ring structure, in addition to R 18 X The substituents on the remaining atoms outside the base are each independently:

a hydrogen atom, a halogen atom, a C 1 -C 12 alkyl group, a C 5 -C 7 cycloalkyl group, a C 1 -C 4 alkyl group substituted by a C 5 -C 7 cycloalkyl group, a phenyl group, optionally one or more C 1 -C 4 alkyl, carboxy, C 1 -C 12 alkyl acyl, arylcarbonyl, heteroarylcarbonyl, phenyl, halogen atom, CN substituted phenyl, C 1 -C 4 alkyl Benzyloxy, R 1 C(O)O substituted C 1 -C 4 alkoxy, C 1 -C 3 alkylenedioxy, R 1 C(O)O, C 1 -C 12 alkyl sulphide , C 1 -C 4 alkylphenylthio, R 1 C(O)O substituted C 1 -C 4 alkylthio, CN, carboxyl, C 1 -C 12 alkoxycarbonyl, aryl Acyl, heteroaryl formyl, XR 18 ;

Or a ring structure between two adjacent substituents of the above substituent of Ar 1 or a substituent and Ar 1 are bonded through a straight bond, a carbon atom or a carbonyl group;

X is O, S or NR 19 ;

Y 1 is O, S, NR 20 , BR 20 , CR 15 R 16 , SiR 15 R 16 ;

R 1 is a hydrogen atom, a C 1 -C 18 alkyl group or a C 1 -C 18 alkoxy group, optionally substituted by one or more halogen atoms, a C 1 -C 4 alkyl group, a C 5 -C 7 cycloalkyl group, a hetero Cycloalkyl, phenyl, heteroaryl, CN, C 1 -C 4 alkanoyloxy, aroyloxy substituted and/or C 5 -C 7 cycloalkylene, phenylene, O, S, NR 17 inserted C 2 -C 18 alkyl, C 2 -C 18 alkenyl, optionally substituted by one or more halogen atoms, C 1 -C 4 alkyl, C 5 -C 7 cycloalkyl, heterocycloalkyl , phenyl, heteroaryl, CN, C 1 -C 4 alkanoyloxy, aroyloxy substituted and/or inserted by C 5 -C 7 cycloalkylene, phenylene, O, S, NR 17 C 2 -C 18 alkenyl;

Or R 1 is C 5 -C 7 cycloalkyl, optionally substituted with one or more C 1 -C 4 alkyl group, a phenyl group, a halogen atom, CN substituted C 5 -C 7 cycloalkyl; or R 1 is phenyl a phenyl group optionally substituted by one or more C 1 -C 4 alkyl groups, a C 1 -C 4 alkoxy group, a phenyl group, a halogen atom or a CN; or R 1 is a naphthyl group; or R 1 is a benzene group An acyl group, a phenoxycarbonyl group, wherein the phenyl group is optionally substituted by one or two or more halogen atoms, R 17 , C 5 or C 6 cycloalkyl, CN, OH, XR 17 ;

R 17 is C 1 -C 4 alkyl;

R 18 is a hydrogen atom, a C 1 -C 18 alkyl group, a C 1 -C 4 alkoxyacyl substituted C 1 -C 5 alkyl group, a R 1 C(O)O substituted C 1 -C 4 alkyl group, Any one or more halogen atoms, C 1 -C 4 alkyl, C 5 -C 7 cycloalkyl, heterocycloalkyl, phenyl, heteroaryl, CN, C 1 -C 4 alkanoyloxy, Aroyloxy substituted or C 2 -C 18 alkyl group inserted by C 5 -C 7 cycloalkylene, phenylene, O, S, NR 17 ; or R 18 is C 5 -C 7 cycloalkyl, Or any C 5 -C 7 cycloalkyl substituted by one or more C 1 -C 4 alkyl, phenyl, halogen atom, CN; or R 18 is phenyl, optionally by one or more C 1 -C C12 alkyl, carboxy, C 1 -C 12 alkyl group, phenylene, O, S, NR 17 inserted into the C 2 -C 12 alkyl group, C 5 -C 6 cycloalkyl, formyl, C 5 a C 6 cycloalkyl substituted C 2 -C 4 alkyl acyl group, an aryl carbonyl group, a heteroaryl formyl group, an XR 17 group, a phenyl group, a halogen atom, a CN, a NO 2 substituted phenyl group;

Or R 18 is C 1 -C 4 alkyl acyl group, C 1 -C 4 conjugated enoyl group, benzoyl group, phenoxycarbonyl group, wherein phenyl group is optionally substituted by one or two or more halogen atoms, R 17 , C 5 Or C 6 cycloalkyl, CN, OH, XR 17 substituted;

Or R 18 described above is bonded to an aromatic ring in Ar 1 or Ar 2 through a straight bond, a carbon atom or a carbonyl group to form a new ring.
The photocurable solder resist ink according to claim 1, wherein the cyclopentanone oxime ester photoinitiator of the formula (I) is a compound of the formula (II) or the formula (III).
The photocurable solder resist ink according to claim 1, wherein component B further contains other photoinitiators as co-initiators, and other photoinitiators are selected from the group consisting of α-aminoketones, thioxanthones, and acylphosphine oxides. , benzophenones, oxazolidinyl esters or aryl-1,2-dione-2-decyl esters.
The photocurable solder resist ink according to claim 3, wherein the specific compounds of the other photoinitiators are:

2-methyl-2-(4-morpholinyl)-1-[4-(methylthio)phenyl]-1-propanone, 2-dimethylamino-2-benzyl-1-(4- Morpholinylphenyl)-1-butanone, 2-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, Bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 4,4'-di(dimethylamino)benzophenone, 9-ethyl-6-(2-methylbenzamide Acyl)carbazole-3-ethanone oxime-O-acetate, 9-ethyl-6-(2-methylbenzoyl)carbazole-3-(3-cyclopentyl)acetone oxime-O- Acetate or 1-(4-phenylthio)phenyl-1,2-octanedione-2-indole-O-benzoate.
The photocurable solder resist ink according to any one of claims 1 to 4, further comprising:

(E) Solvent, in an amount of from 100 to 300 parts by mass.
The photocurable solder resist ink according to claim 1, which is used as a coating film having a thickness of 15 to 100 μm after drying, and the coating film is developed by a dilute alkali solution after exposure through a mask to form a pattern.
A dry film obtained by applying the photocurable solder resist ink according to claim 1 to a substrate and then drying the film.