JPS61171782A - Solder resist ink composition - Google Patents

Abstract

PURPOSE:To provide the titled composition composed of a specific linear high- molecular cresol-novolac resin, an epoxy resin, an amine-type cure accelerator and a specific solvent, giving a cured coating film having excellent heat- resistance, chemical resistance and adhesivity to various substrate and applicable by screen printing. CONSTITUTION:The objective composition contains (A) a linear high-molecular cresol-novolac resin having a number-average molecular weight of >=1,500 and excellent solubility in solvents, and selected from (i) o-cresol-novolac resin and (ii) o-cresol/p-cresol random-copolymerized novolac resin having a molar ratio of copolymerized o-cresol/p-cresol of >=50/50, (B) an epoxy resin having >=2 epoxy groups, (C) an amin-type cure accelerator, and (D) a solvent of formula I-III (R is R' ar 1-8C alkyl; n is 1-4). The amount of the epoxy group in the component B is 0.5-1.5 equivalent per 1 equivalent of the OH group of the component A. The amounts of the components C and D are 0.01-10pts.(wt.) and 20-100pts. per 100pts. of A+B.

Description

[Detailed description of the invention] The present invention relates to solder resist ink compositions.

(Industrial Application Field) The solder resist ink composition of the present invention can provide a cured film with excellent heat resistance, electrical insulation, and adhesion to various substrates, so it is suitable for printed wiring boards, especially polyimide. , ceramics and metals (e.g. aluminum)
It can be advantageously used as a solder resist ink for printed wiring boards using heat-resistant substrates such as.

(Prior art) Solder resist is usually screen printed on the surface of printed wiring boards, and is used to protect electrical and moisture-resistant circuits, selectively protect circuits during soldering, and protect boards during plating processes. Used (1!# Kaisho 54-156167,
JP-A-55-53478 and JP-A-55-46165
(issues of each publication).

For example, an example of a double-sided printed wiring board will be explained with reference to FIGS. 1 and 2. For example, perforations 3 are formed in a copper foil 1 provided on both sides of a polyimide insulating board 2 using a laser beam, and then the copper foil is removed. A printed wiring is formed by selectively removing the etching, and then a solder resist 4 is screen printed on both sides of the printed wiring to obtain a double-sided printed wiring board.

By inserting the lead wires 7 of the parts 6 into the necessary locations on this double-sided printed wiring board and soldering them, the steel foil l is fixed with the solder 5 and electrical conduction is established. It will be done.

Glass fiber-reinforced epoxy resin was mainly used as the insulating plate 2 of this printed wiring board, and melamine resin was initially used as the solder resist, but now it has improved adhesion, chemical resistance, and electrical insulation. Epoxy resins with excellent properties are mainly used.

In recent years, as the insulating substrate 2, metal substrates such as polyimide film, fluororesin film, ceramic substrate, iron, aluminum, etc., which have better heat resistance and electrical insulation properties, have been used instead of epoxy resin9. There is also a growing demand for solder resists with better heat resistance.

Conventionally, in the formulation of epoxy resin compositions used for solder resists, difunctional bisphenol AM epoxy resins, or K is polyfunctional phenol novolac type epoxy resins or 0-cresol novolac dispersion epoxy resins are used to improve heat resistance. Nine types of hardeners are used by blending aromatic abans, acid anhydrides, etc. with resin as a curing agent. However, such formulations had drawbacks such as the cured product did not exhibit sufficient heat resistance and was easily cured, resulting in poor ink stability.

Furthermore, when a novolak resin and a curing accelerator are blended with the epoxy resin, the stability of the ink is improved and a solder resist with excellent water resistance and chemical resistance can be obtained. However, since the molecular weight of the phenol novolak resin and cresol novolac resin conventionally used in such cases was low, the cured resin still did not exhibit sufficient heat resistance, and had the disadvantage of being brittle and lacking in toughness.

(Problems to be Solved by the Invention) The present invention can provide a cured film with excellent heat resistance, chemical resistance, and adhesion to printed wiring boards, and also has four excellent ink stability and is screen printable. The present invention aims to provide a complete solder resist ink composition.

(Structure of the Invention) The ink composition for solder resist of the present invention includes (A)
o-cresol novolak resin and O-cresol/p
A line with excellent solvent solubility, selected from O-cresol/p-cresol random copolymerized novolac resins with a cresol copolymerization molar ratio greater than 50,150, and a number average molecular weight of 1,500 or more as measured by vapor pressure method using methyl ethyl ketone as a solvent. (B) an epoxy resin having two or more epoxy groups in one molecule, (C) an amine curing accelerator, and (D) the general formula % formula % (in each formula, R and R' each represents an alkyl group having 1 to 8 carbon atoms, and n represents an integer of 1 to 4. The cresol novolac resin of (A) and the epoxy resin of (B) contain a solvent that dissolves the cresol novolac resin of The epoxy group is contained in a proportion of 0.5 to 1.5 equivalents,
(C) based on 100 parts by weight of the cresol novolak resin (A) and the epoxy resin (B).
0.01 to 10 parts by weight of the amine-based curing accelerator;
A composition characterized in that the solvent D) is contained in a proportion of 20 to 100 parts by weight.

The cresol novolak resin (A) contained in the solder resist ink composition of the present invention is an O-cresol novolak resin and an O-cresol/p-cresol random copolymerized novolak resin having a mixed molar ratio of O-cresol/p-resol of greater than 50,150. A linear high molecular weight cresol novolac resin with excellent solvent solubility and a number average molecular weight of 1500 or more as measured by vapor pressure method using methyl ethyl ketone as a solvent. The novolak resin (A) used in the present invention has a remarkable molecular weight.
i.

Despite its large size, it has excellent solubility in various solvents used in ordinary varnish manufacturing, especially the solvent (D) used in the present invention, and is compatible with various epoxy resins. It is also excellent. To this end, the solder resist ink composition of the present invention is uniform and transparent varnish-like, and the film obtained by applying and drying it has a high glass transition point and high thermal stability when cured. , resulting in a uniform cured film with excellent electrical insulation and adhesion to various substrates. Therefore, the solder resist ink composition of the present invention can be applied to printed wiring boards, 4! It is suitable for manufacturing printed wiring boards with excellent heat resistance.

The cresol novolac resin (A) used to prepare the solder resist ink composition of the present invention is
For example, O-cresol, or a mixed cresol of O-cresol and p-cresol with a molar ratio of 0-cresol/p-cresol greater than 50150, can be easily converted into formaldehyde by heating with formaldehyde, haparaformaldehyde, trioxane, etc. It can be easily produced by polymerizing it together with the formaldehyde compound generated in a polar solvent such as an alkyl alcohol or an organic carboxylic acid using an acidic catalyst.

The cresol used to manufacture the novolak resin is
When the p-cresol content increases, the softening point and heat resistance of the produced novolac resin improve, but the solubility in solvents decreases, so 0-cresol is used alone or
or 0-cresol/p-cresol mixing molar ratio is 50
Greater than 150, preferably greater than 60/40,
Preferably, a mixed cresol of O-cresol and p-cresol of greater than 90/10 is used.

As the aldehyde for producing the novolac resin, formaldehyde or a formaldehyde compound that easily generates formaldehyde upon heating, such as paraformaldehyde or trioxane, is used. Trioxane and paraformaldehyde are particularly preferred since they have no risk of increasing the water content of the reaction system. These aldehydes are used in a ratio of 0.7 to 1.5 mol, preferably 0.9 to 1.3 mol, of formaldehyde per mol of cresol. If the amount of aldehyde is too small, only a low molecular weight novolak resin will be obtained, and if it is too large, the resulting resin will tend to gel, so both are unfavorable.

Polar solvents such as alcohol, glycol ethers of alkyl alcohols having 3 to 12 carbon atoms, and organic carboxylic acids having 1 to 6 carbon atoms are used. As the alcohols and glycol ethers, those having a high boiling point and excellent solubility of the novolac resin are preferable, such as propatool, butanol, amyl alcohol, hexanol, benzyl alcohol, methoxyethanol, ethoxyethanol, Butoxethanol and the like are preferred.

Further, as the organic carboxylic acid, formic acid, acetic acid, propionic acid, butyric acid, etc. are preferable. The amount of the reaction solvent used is 150 to 300 parts by weight based on 100 parts by weight of the raw material cresol.

As the catalyst for the novolac resin production reaction, acid catalysts such as protonic acids such as hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, toluenesulfonic acid, citric acid, methanesulfonic acid and perchloric acid are used. However, boron trifluoride, boron trifluoride ether complex, aluminum trichloride, tin tetrachloride, which are described as preferred catalysts in JP-A-57-113 and JP-A-56-92908, Lewis acids such as zinc chloride are unsuitable. The amount of acid catalyst used is 0.01 to 20 parts by weight per 100 parts by weight of raw material cresol,
Preferably it is 1 to 15 parts by weight.

To explain in detail an embodiment of the method for producing the novolak resin, for example, (1) the raw materials cresol, aldehyde, solvent, and catalyst are placed in a reaction vessel and heated while stirring to reach the reaction temperature; (1) Charge the raw material cresol, a solvent, and a catalyst, raise the temperature to reach the reaction temperature, and then add a solution of the aldehyde and catalyst in 4 ml of solvent, or (2) separate the raw material cresol, aldehyde, and solvent.

! :1 A method is used, such as charging the mixture into a bottom container, heating it to near the reaction temperature while stirring, and dropping the catalyst or catalyst solution.

When producing a random copolymer resin of O-cresol/p-cresol, it is necessary to thoroughly mix both cresols in advance.

The reaction temperature is 95°C or higher, preferably 105-150°C. At low temperatures, the reaction progresses slowly, and at high temperatures, gel components tend to occur.

If there is a lot of water in the reaction system, formaldehyde will be consumed in side reactions, the amount used for polymerization will decrease, and the molecular weight will not increase. Furthermore, if a high molecular weight novolac resin has a high water content, it will not be soluble in a solvent and will precipitate, resulting in a heterogeneous reaction, making it difficult to increase the molecular weight. For this purpose, the reaction is carried out with the water content of the reaction system being 15% by weight or less, preferably 10% by weight or less. In this case, it is recommended to let the reaction decay under reflux using a solvent such as n-butanol, which can be separated azeotropically from water, and remove the water produced by the reaction as an azeotrope. , is extremely effective in removing moisture.

Separation of cresol novolak resin after completion of reaction, water soluble solvent as solvent, methoxyethanol,
When ethoxyethanol, acetic acid, formic acid, etc. are used, they are poured into 10 to 20 times the amount of water and recovered as a water-insoluble resin by precipitation. In addition, when a water-insoluble solvent is used as the solvent, after the catalyst is removed by washing with water or neutralization, one solvent is distilled off, and the resin is extracted and recovered as a molten resin.

The O-cresol novolac resin obtained in this way can be used in combination with carboxylic acids such as acetic acid and propionate; alkyl alcohols such as methanol, ethanol, and butanol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and microhexanone; ethyl acetate and butyl acetate. It is easily soluble in esters such as; ethers such as tetrahydrofuran and dioxane; and glycols such as methoxyethanol and butoxyethanol. Since the resin is readily soluble in various solvents and no insoluble gel content is observed, it can be seen that this resin is a linear resin.

In addition, the cresol novolac resin obtained from the O-cresol and p-cresol mixture as described above is a random copolymer and is soluble in ethers such as tetrahydrofuran and dioxane; dimethylacetamide and dimethylformamide. The fact that no insoluble matter was observed indicates that this resin is also a linear resin.

In the case of this copolymer resin, the solubility in the solvent changes depending on the molar ratio of 0-cresol and p-cresol and the molecular weight. The higher the molar ratio of p-cresol,
Moreover, the higher the molecular weight, the more difficult it is to tolerate. For example, resins with a molar ratio of O-cresol/p-cresol of 50,150 and a softening point of 145°C or higher include ketones such as acetone and methyl ethyl ketone; glycol ethers such as methoxyethanol and ethoxyethanol; d vinegar; and esters such as ethyl. : Soluble in epichlorohydrin, but poorly soluble in alcohols such as methanol and ethanol. Such extremely poorly soluble copolymer resin minerals are unsuitable for the cresol novolac resin of the present invention, and even if the molar ratio of 0-cresol/p-cresol is 5015081 degrees, the molecular weight is relatively small. , the softening point is 145
If the temperature is lower than the temperature, it becomes soluble in methanol and the like, so it can be used as the cresol novolak resin of the present invention.

The 0-cresol novolac resin produced as described above or the 0-cresol/p-cresol molar ratio is 5.
O-cresol/p-cresol random copolymer resins larger than 0150 usually have a number average molecular weight of 1500 to 5 as measured by the steam method using methyl ethyl ketone as a solvent.
000, the ratio (Q) of the weight average molecular weight measured by gel permeation chromatography using tetrahydrofuran as a solvent and the above number average molecular weight is 1.5 to 12, and is compatible with methanol and acetone. Since it is molten,
Any of such cresol novolak resins can be suitably used as the (A) cresol novolac resin of the present invention.

? ! Wow 5, okay. □ 工、6ゎえ7、-tthbpv
A solder resist ink composition of the present invention was prepared using an n-sol novolac resin, and the physical properties of the cured resin obtained from the composition were examined, and the results showed that it had excellent lateral uniformity and high heat resistance. Ta. In particular, when using a cresol novolac resin that has a number average molecular weight of 2100 or more and a softening point of 145°C or more as determined by the softening point measurement method, which measures the temperature at which the resin powder becomes fluid and transparent under a microscope, heat resistance may be poor. It was significantly better. In the case of O-cresol/p-cresol random copolymer resin, the solubility decreases as the p-cresol content increases, so the O-cresol/p-cresol copolymer molar ratio is set to 50.
It is necessary to make the same molar ratio larger than 150, preferably larger than 60750, more preferably 90/10.
It turns out that it is desirable to make it larger.

Note that even if p-cresol is used alone and polymerized with formaldehyde using a sulfuric acid catalyst in ethoxyethanol, a linear high molecular weight p-cresol novolak resin with a softening point of 300° C. or higher can be obtained. However, this resin had poor solubility in solvents, and was hardly soluble in the various solvents mentioned above except for tetrahydro-7-ran, dioxane, dimethylformamide, and dimethylacetamide. Also,
This resin has poor compatibility with epoxy resin, and both resins are
Even if heated and mixed at a temperature of 50°C or higher, they do not dissolve uniformly.

An attempt was made to dissolve this high molecular weight p-cresol novolak resin in glycol ethers, diglycol ethers, or their esters, which are the solvents (D) used in the present invention, but the solubility was poor and the dissolution was uniform. did not dissolve in the For example, an attempt was made to dissolve the high molecular weight p-cresol novolak resin in the above solvent using a fine powder obtained by re-precipitation, but the resin was insoluble in the solvent. Only suspended ink is obtained, and the cured product is authentic and contains many uncured parts.
The solder resist obtained from this ink had poor water resistance and was significantly inferior in durability.

Next, the solder resist ink composition of the present invention contains (A) the linear high molecular weight cresol novolac resin detailed above as well as CB) an epoxy resin having two or more IC epoxy groups in the molecule as an essential component. but,
Various kinds of epoxy resins can be used as the (B) epoxy resin. For example, bisphenol A1 bisphenol F
, bisphenol 3, phenol novolak, O-cresol novolak, 1,1,2,2-tetrakis(4
- Epoxy resins manufactured from polyphenols such as hydroxyphenyl)ethane and epihalohydrin; Epoxy resins manufactured from polyhydric phenols such as catechol, resorcinol, and hydroquinone and epihalohydrin; ethylene glycol, butanediol, pentaerythritol, polyethylene glycol Epoxy resins based on glycidyl ethers of polyhydric alcohols such as; alicyclic epoxy resins such as synchropentadiene dioxide, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, vinylcyclohexene dioxide; Examples include polyglycidyl ester type epoxy resins of polycarboxylic acids such as hydrophthalic acid, polyglycidyl amines such as glycidylated products of diaminodiphenylmethane, and epoxy resins such as glycidylated products of aminophenol. Furthermore, as the epoxy resin, various flame-retardant epoxy resins containing halogenated aromatic nuclei can be used. Examples of flame-retardant epoxy resins containing such /10-genated aromatics include glycidyl ethers of tetrabromobisphenols and glycidyl ethers of brominated phenol novolac resins. If such a flame-retardant epoxy resin is used, the cured film of the exposed resist ink can be easily rendered flame-retardant.

(C) in the solder resist ink composition of the present invention
Examples of amine curing accelerators include tertiary amines such as benzyldimethylamine and trisdimethylaminomethylphenol; secondary amines such as piperidine; salts of imidazoles, imidazoles and BP, and phorboxic acid, such as BF. , ·piperidine, BP, ·2-methylimidazole, 2-methylimidazole acetate, etc. The usage amount of these amine curing accelerators is as follows:
(A) Linear high molecular weight cresol novolac resin and (B
) 0.01 per 100 parts by weight of the total amount of epoxy resin
~10 parts by weight, preferably 0.1 to 5 parts by weight.

(D) in the solder resist ink composition of the present invention
As the solvent, a solvent consisting of at least one compound represented by any of the above general formulas and which dissolves the cresol novolac resin (A) and the epoxy resin (B) is used. . The reason for using such specific solvents is that these solvents have high boiling points and are difficult to volatilize, making them particularly suitable for use in solder resist inks that require a long pot life. This is because there is no risk of damaging the printing screen. Variant examples of such solvents include ethyl cellosolve, isoprovil cellosolde,
Examples include butyl cellosolve, amylceronlube, diethylene glycol monoacetate, ethyl carpitol, butyl carpitol, cellosolve acetate, carpitol acetate, etc., and these solvents can be used as a mixed solvent of two or more types depending on the case.

The amount of solvent (D) used in the present invention is 20 to 100 parts by weight, preferably 25 to 100 parts by weight, based on 100 parts by weight of the total amount of (A) linear high molecular weight cresol novolak resin and (B) epoxy resin. It is 50 parts by weight.

If the amount of solvent is too small, the fluidity of the ink will be poor, resulting in poor screen printing properties on wiring boards.On the other hand, if it is too large, a thick film will not be obtained after printing, and the heat resistance of the cured film will be affected. Deteriorate.

The solder resist ink composition of the present invention may contain various additives, if necessary, in addition to the components (A) to (D) described above.

For example, 7 various pigments including talocyanine blue; fillers such as silica, talc, and alumina; 1 browning agents such as colloidal silica; 1 leveling agents such as silicone; flame retardants such as anti-sulfide, etc. It can be made to contain. The content of these additives is as described in (A) to (D) above.
The total amount of fillers is 50 parts by weight or less, and the total amount of additives other than fillers is 10 parts by weight per 100 parts by weight of each essential component.
Parts by weight or less.

The solder resist ink composition of the present invention can be prepared in various ways. For example, components (A) to (
D) and additives such as pigments may be simultaneously mixed and dissolved at a temperature of about room temperature, or components (A), (B),
(D) and additives such as pigments may be mixed, heated to dissolve at a temperature below the boiling point of component (D) and not exceeding 200°C, and after cooling, component (C) may be added and mixed. good.

The solder resist ink composition of the present invention is usually applied to a wiring board using a screen printer. Then, if the coating is heated at about 130 to 200° C. to scatter the solvent and cured at the same time, a cured film with high heat resistance is formed, and the cured film is excellent as a protective film.

(Effects of the Invention) The solder ink composition of the present invention is uniform, and the cured film obtained by applying, drying, and curing the composition has excellent heat resistance, electrical insulation, and adhesion to a substrate. Therefore, the solder ink composition of the present invention is particularly suitable as a solder resist ink for printed wiring boards using various heat-resistant substrates including polyimide, fluororesin, various ceramics, and various metals such as aluminum.

(Examples, etc.) Next, the present invention will be further described in detail with reference to production examples, examples, and comparative examples of novolac resins.

Novolac resin production example 1 0-cresol 108g, paraformaldehyde 32g
and 240 g of ethyl cellosolve were charged into a reactor together with 10 g of sulfuric acid, and the reaction was carried out at 115° C. for 4 hours with stirring.

After the reaction was completed, 17 liters of ONaHCOs and 311 liters of water were added to neutralize, and the reaction solution was poured into 2 liters of water under high speed stirring, and the precipitated resin was separated and dried.
g of cresol novolak resin was obtained.

This resin was soluble in methanol, ethanol, butanol, octatool, ethyl cellosolve, ethyl cellosolve, tetrahydrofuran, dioxane, acetone, methyl ethyl ketone, and ethyl acetate, and no gel content was observed. However, it was insoluble in benzene, tolaene, xylene, chloroform, and carbon tetrachloride.

The molecular weight of this resin was determined by vapor pressure method (in methyl ethyl ketone,
When measured at 40°C (hereinafter the same), the number average molecular weight was 2,600. The softening point of the resin determined by microscopy was 155°C. Furthermore, gel permeation chromatography analysis of 1-tetrahydrofuran solution (hereinafter referred to as
It is called rGPcJ. ) was 3.0.

Novolak resin production example 2 The amount of paraformaldehyde used was changed to 35.2.9, and the amount was reacted in the same manner as in Example 1, and the same treatment was performed to obtain a cresol novolak resin.

The number average molecular weight of this resin measured by vapor pressure method is 3.40.
The softening point measured by microscopy was 175°C. Moreover, the Q value by GPC was 6.8.

Novolac resin production example 3 86.49 (0.8 mol) of 0-cresol and 21.6 g (0.2 mol) of p-cresol were dissolved in ethyl cellosolve 24G and fK, and 32 g of paraformaldehyde was added.
and 10 g of sulfuric acid were added, and the mixture was reacted at 105° C. for 6 hours with stirring.

Next, 17I of NaHCOs and 301 of water were added to neutralize, and after 9 hours, the reaction product was poured into 2J of water while stirring,
Separate the precipitated resin by F and dry it to 112! Resin i was obtained. This resin had a number average molecular weight of 2,600 and a softening point of 165°C.

This resin was soluble in methanol, ethanol, butanol, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, tetrahydrofuran, dioxane, and ethyl acetate, but insoluble in benzene, toluene, chloroform, and trichloroethylene.

Novolac resin production example 4 0-cresol 10811, paraformaldehyde 29
．． 31i, and n-butanol 2401t were charged into a reactor together with 15 g of P-toluenesulfonic acid, and reacted at 110 to 115° C. for 4 hours with stirring. At this time,
The reaction was carried out while the produced water was discharged from the system using a separator.

After the reaction was completed, the butanol phase was separated after neutralization and washing with 300 I water containing 179 NaHCOs, and the butanol was distilled off by heating. Obtained. This resin has a number average molecular weight of 1900 and a softening point of 130°C.

Novolac Resin Production Example 5 This example is a production example of a novolac resin used in a comparative example.

p-cresol 108g, rose formaldehyde 32J
i' and ethyl cellosolve 8001 were charged into a reactor together with 10 g of sulfuric acid, and reacted at 115° C. for 6 hours with stirring.

After the reaction was completed, 1710 NaHCOs and 30 Ii of water were added to neutralize, and then the reaction product solution was poured into 4 bottles of water under high speed stirring, and the precipitated resin was separated from F and dried to obtain a resin of 117.9. .

The number average molecular weight of this resin determined by vapor pressure method using dimethylacetamide was 1800, and the softening point was 300°C or higher. This resin was soluble in tetrahydro-7rane, dioxane, dimethylacetamide, and dimethylformad, but insoluble in alcohols, ketones, and aromatic hydrocarbons.

(9) Glycol ethers had IL% insoluble matter which was partially dissolved, and the solution was cloudy. Furthermore, this resin did not dissolve K in any of the bisphenol type epoxy resin, phenol novolac type epoxy resin, profluorinated bisphenol type epoxy resin, and 0-cresol novolac type epoxy resin.

The examples in Novolac resin production examples are also production examples of novolac resins used in comparative examples. ! 1゜0-
Cresol 108II, 37% formalin 739, and oxalic acid II were charged into a reactor and reacted at 90°C for 1 hour, and then heated to 120°C and reacted for 4 hours.

After the reaction was completed, 100.9% of water was added to settle the produced resin, the water was removed by decantation, and 100.9% of water was added.
Dehydrated under reduced pressure of mmHg and gradually increased to 140 kK temperature.
When the temperature reached 0.degree. C., the resin was MR-extruded in a molten state, solidified by cooling, and pulverized. Resin 115 II was obtained. This resin had a number average molecular weight of 490 measured by the same vapor pressure method as in Production Example IK), and a softening point of 60° C. by microscopy.

Example 1 Glycidyl ether of phenol novolak resin (Yuka Shell Epoxy Co., Ltd. trade name: Ebiko) 154) 6ell
, Glycidyl ether of brominated phenol novolac (Nippon Ka Co., Ltd. trade name Prene) 4011 Production Example 1
High molecular weight cresol novolak resin 5777 obtained in
．． 2-phenylimidazole 1g, fine powder silica (Japan Aerosil Co., Ltd. trade name Aerosil 380) 4.9, talc 2
0g, antifoaming agent (Nippon Niniker Co., Ltd. product name L-722)
0.5 i Phthalocyanine Green 311 and n-
Etelcalpitol 459 was mixed at room temperature to prepare a solder resist ink. In this case, the epoxy group equivalent of the epoxy resin was 1 relative to the OH group equivalent of the novolac resin.

This ink was spread on a steel through-hole polyimide substrate using a screen printing machine (180 mesh, polyester plate, emulsion thickness 20μ) to a film thickness of approximately 25μ, and was cured by heating at 200℃ for 60 minutes. A steel-clad printed wiring board having a protective film was obtained.

The following tests were conducted on the protective film of this copper-clad printed wiring board, and the results are shown in Table 1.

Adhesion...JIS C-0202 goblin adhesion test. The coating film KIXI- of the test piece was cut into 100 goblets of the size and peeled off with cellophane tape, and then the adhesion was evaluated.

Solder resistance: J I 8 C-64812 It was immersed in molten tin solder of 60 tin at 60° C. for 2 minutes and 4 minutes, and evaluated based on the state of the coating film. The criteria for this judgment are as follows.

○...No abnormality in the appearance of the paint film ×...Blistering, peeling, and melting heat deterioration test of the paint film...J I S C-6481250℃ dryer (
The condition and adhesion of the coating film after aging for 72 hours in an open oven) were evaluated according to the following criteria.

O: No abnormalities ×: Blistering and peeling of paint film Examples 2 to 4 Solder resist ink was produced in the same manner as in Example 1, using the nine formulations listed in Table 1. Similarly, a steel-clad printed wiring board with a protective film was manufactured and tested, and the results are shown in Table 1. Among these, the epoxy group equivalent to the OH group equivalent of the novolac resin in these six examples was 1 in Example 2, 1 in Example 3, and 1 in Example 4.

Comparative Examples 1 to 2 The formulations listed in Table 1 were used, and the rest was as in Example IKk.
A solder resist ink was produced in accordance with the method described above, and a steel-clad printed wiring board having a protective film was produced in the same manner and tested. The results are shown in Table 1.

Notes to Table 1: $1.2.3...All are product names of Yuka Shell Epoxy Co., Ltd.Yellow 4......Product name of a certain company, Nipponka Co., Ltd.

[Brief explanation of drawings]

Figure 1 is a partial cross-sectional view showing a printed wiring board before solder resist printing, and Figure 2 shows a printed wiring board like the one shown in Figure 1 after solder resist printing was applied and the lead wires of the components were soldered. FIG. 2 is a partial cross-sectional view showing a printed wiring board. Each symbol in the figure indicates the following. 1... Steel foil 2... Polyimide insulating plate 3... Perforation 4... Solder resist 5... Solder 6... Part 7... Lead wire Patent applicant Mitsubishi Yuka Co., Ltd. Figure 1 Figure 2

Claims (1)

[Scope of Claims] 1) (A) selected from o-cresol novolac resins and o-cresol/p-cresol random copolymerized novolac resins having an o-cresol/p-cresol copolymerization molar ratio greater than 50/50; A linear high molecular weight cresol novolak resin with excellent solvent solubility, having a number average molecular weight of 1500 or more as measured by vapor pressure method using methyl ethyl ketone as a solvent, (B) an epoxy resin having two or more epoxy groups in one molecule, ( C) Amine curing accelerator, and (D) General formula R-(OCH_2CH_2)-_nOH ▲There are mathematical formulas, chemical formulas, tables, etc.▼, and ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In each formula, R and R' each represents an alkyl group having 1 to 8 carbon atoms, and n represents an integer of 1 to 4. The cresol novolak resin of (A) and the epoxy resin of (B) contain a solvent that dissolves the cresol novolac resin of The epoxy group is contained in a proportion of 0.5 to 1.5 equivalents,
0.01 to 10 parts by weight of the amine curing accelerator (C) and 100 parts by weight of the cresol novolac resin (A) and the epoxy resin (B);
1. A solder resist ink composition comprising 20 to 100 parts by weight of each solvent. 2) (A) Cresol novolac resin has 3 to 1 carbon atoms
In a polar solvent selected from the group consisting of alkyl alcohols of 2, benzyl alcohol, glycol ethers of alkyl alcohols having 3 to 12 carbon atoms, and organic carboxylic acids having 1 to 6 carbon atoms, in the presence of an acidic catalyst. , o-cresol or o-cresol/p-cresol molar ratio is 5
2. The composition according to claim 1, which is a cresol novolac resin obtained by reacting a mixed cresol of o-cresol and p-cresol with a ratio of 0/50 or more to formaldehyde. 3) (A) Cresol novolac resin has a softening point of 145°C
The composition according to claim 1 or 2, which is the above composition.