JPS603113B2 - Epoxy resin varnish for printing and coating inks - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the composition of an epoxy resin varnish,
Especially as a coating ink for printing or solder resist, etc., it has excellent pot life, viscosity, and printing workability, and when used as a coating ink for various purposes, it has good chemical resistance (especially alkali resistance) and physical properties of the coating after multiple firings. The present invention provides a varnish that exhibits excellent properties such as silver migration prevention effect for printed circuit undercoating.

-Liquid resins used for coatings such as printing inks and protective film formation are called varnishes.
Conventional varnishes are often simply a solid resin dissolved in a solvent or a combination of liquid resins.

These resin varnishes are used as basic resin materials for solder resists, printed resistors, protective films for various printing inks, and base materials. In recent years, it has been used as a base for silver electrodes, a protective film that prevents migration in humidity as a coating, a varnish that has flexibility after film formation as a protective film for flexible substrates, and a chemical-resistant protective film (especially alkali-resistant).
It has chemical resistance and flexibility as a varnish used for
There is a need for a varnish that can be cured quickly and that can be phosphorized multiple times at high temperatures of about 16° to form a multilayer film. Conventional varnishes have achieved their characteristics by combining several types of resins such as epoxy fer/fer and epoxy melamine, but they have been improved by combining physical properties such as flexibility, long-curing properties, and chemical resistance, as well as by multiple firings and evaporation. It was not possible to completely meet all requests such as migration prevention.

The present invention solves the physical properties and characteristics required for these varnishes by combining the molecular weights of epoxy resins, that is, by combining a liquid epoxy resin and a solid epoxy resin. For comparison, typical compositions of conventional varnishes are as follows. Subsidiary example 1 Ingredients Parts by weight Solid epoxy resin (100%) 65%
Agent 304'/4' diamino, diphenylmethane 5 Also, in general, printed wiring boards made from copper-clad laminates are produced by bonding steel foil onto an insulating substrate such as plastic, and then forming the desired circuit on the steel foil. It is manufactured by printing a pattern, removing the parts other than the printed circuit pattern by etching, washing with water, applying flux, and attaching components, lead wires, etc. by soldering.

In such printed wiring boards, as circuits have become more complex and finer in recent years, it has become necessary to prevent circuits from shorting due to soldering. Solder resist tint is applied by screen printing, etc., except for the parts to be soldered on the slope, and cured with phosphorus to form a solder protective film, so that solder does not adhere to parts other than the parts to be soldered during the soldering process. It is designed to protect you. Furthermore, in recent years, so-called double-sided printed wiring boards, in which circuit patterns are formed not only on one side but on both sides of the wiring board, have become popular in order to further increase the density of circuits.

In such double-sided printed wiring boards, it is necessary to electrically connect the circuit patterns on both the front and back sides, and for this purpose, a through-hole method is generally used in which a hole is made in the center of the copper foil and a conductor is placed on the side wall of the hole for connection. ing. Various types of through-hole connection methods have been considered, but the connection method in which the through-hole conductor is plated is generally superior in terms of characteristics such as continuous workability, cost, and through-hole reliability. Widely used. Since such a through-hole connection process includes a chemical treatment process called chemical plating, the solder resist ink used is also required to have excellent chemical resistance. Among these, the most severe conditions include the process of leaving the copper laminate layer in approximately 70% electroless laminate solution (Book 12.5) for 6 hours in order to adhere the copper laminate layer to a thickness of approximately 35 mm. The point is that it is Conventionally, varnishes for solder resist inks used in the above-mentioned applications include those whose main components are epoxy-melamine resin, epoxy-urea resin, alkyd-melamine resin, and alkyd-urea resin. It's here.

Generally, solder resist is made by dissolving the two types of resins mentioned above in an organic solvent and coloring them with pigments or dyes. Clay or the like is used as an extender pigment and mixed to uniformly disperse each component to make it suitable for silk screening.Then, it is applied as a film on a printed wiring board by screen printing method 0 and cured to form a solder resist film. It is made to form. In addition, as shown in Tokukan Sho 50-16408, odorless solder resist inks have been recently provided that form solder resist ink using epoxy resin alone, but in this case, printing The drawback is that there are various problems with suitability.

Typical compositions of such conventionally used solder resist inks using varnishes are as follows.

Follow example 2 Ingredients Parts by weight Melamine resin (50%) 35 Alkyd resin (50%) 60 $ Extender pigment
30 colored pigments or dyes
5 Organic solvent
10 Subsidiary example 3 components Part by weight 01 Liquid epoxy resin (100%) 60~
80 extender pigment 10-20
Colored pigment 1-22.4
-dicyano-6-[2-methylisidazolyl-(1')
[Ethyl-S-triamine 3-85] However, in the conventional solder resist ink using varnish, the insulating silk-like polymer film that inhibits solder adhesion is formed by the condensation of two resins. Since it is formed by a reaction, formaldehyde is formed as a by-product during the condensation reaction, and there is a drawback that a formalin odor is emitted when the solder resist tint is cured.

In addition, in order to achieve desired properties such as chemical resistance, heat resistance, electrical properties, and physical strength, it is necessary to form a film as thick as 30 mm, which requires a large amount of ink and is troublesome to print. Moreover, it also has the disadvantage that it takes time to harden. On the other hand, in a solder resist ink made of a single component of epoxy resin as shown in Subexample 3 above, the formalin odor can be eliminated, but the viscosity is 40%.
The temperature is higher than 20°C, making it difficult to work during printing, and curing after printing is slow, taking more than 10 minutes at 150°C. Moreover, after curing, the resin does not reach the parts that require soldering. oozes out, and pH 1 at 70oo
It meets the practical requirements as a solider resist ink for through-holes, such as poor reliability due to partial peeling of the film during the plating process, which requires soaking in a strong alkaline solution of 2.5 for more than 3 hours. It was difficult to say that it was sufficient. Further, when a solvent is added to reduce the viscosity, even if printing workability is improved, problems such as the above-mentioned oozing become more pronounced and heat resistance deteriorates remain.
Therefore, the present invention eliminates all such conventional drawbacks and improves practical varnish properties such as viscosity, printing workability, chemical resistance (especially alkali resistance), heat resistance, far-curing properties, pot life, electrical sacrifice, and physical properties. The object of the present invention is to provide a varnish composition that can satisfy the properties.

Therefore, in the present invention, an epoxy resin prepared by mixing a solid epoxy resin and a liquid epoxy resin in a ratio of 6:4 to 9.5:0.5, an indazole derivative and a dicyandiamide in a ratio of 9:1 to 1: It is characterized by its combination with a curing agent mixed at a ratio of 9:9.

More specifically, 45 to 8 parts by weight of an epoxy resin consisting of 60 to 95 parts by weight of solid epoxy resin and 40 to 5 parts by weight of liquid epoxy resin, 10 to 45 parts by weight of a solvent,
At least the general formula (where R: carbamoylalkyl, cyanalkyl, carboxylalkyl, polyalkoxyalkyl or diamino-S triacylalkyl group, R2: hydrogen atom, alkyl or aryl group, R3:
3 to 1 parts by weight of a curing agent containing an imidazole derivative 6 represented by a hydrogen atom or an alkyl group (R4: a hydrogen atom or an alkyl group) and dicyandiamide in a ratio of 9:1 to 1:9. That is.

When such an epoxy resin varnish is used for a solder resist ink, 1 to 2 of color pigments or dyes are added to the epoxy resin varnish.
The optimum result can be obtained by adding 5 to 3 parts by weight of extender pigment, and 2 to 1 part by weight of extender pigment.
parts by weight of glycidyl ether can also be added.

Adhesives, protective films, etc. can be easily created using the varnish of the present invention, as well as resistive materials and conductive materials can be created by adding dew-conducting substances such as silver and carbon, and paints and protective films can be created by adding colorants. By adding an inorganic filler to the ink for the protective film, it is possible to produce ink, coping material, or film material for special protective films.

Solder and resist tints are one of the most useful applications. In particular, the varnish of the present invention has excellent adhesive strength and flexibility, so it can be used as a protective film for flexible films.It is also long-curing, and its properties do not change much when baked multiple times at high temperatures (160°C). Therefore, it is also used as an ink base material for multilayer printing. As the solid epoxy resin in the present invention, for example, Epicoat 1001
, 10041007, 1009 (Shell Chemical), DE
R664, 667 (manufactured by Dow Chemical) "EP-5100
Liquid epoxy resins such as 175 setone alcohol,
Tetralin, cellosolve acetate, cyclohexane, etc., imidazole derivatives include 2MZ, 4MZ,
is Z (manufactured by Shikoku Kasei), and EP as ditacyandiamide.
Extender pigments such as reagents (manufactured by Hanui Chemicals) include talc (manufactured by Nippon Talc), calcium carbonate, barium sulfate,
Coloring pigments or dyes such as silica, clay, etc.
Grindyl ether derivatives include GOT (
Nippon Kayaku), Eporite 4200440li 4004 (
(manufactured by Kyoeisha Yushi Kogyo), etc. can be used.

Hereinafter, the present invention will be described in detail based on examples.

The characteristics of the epoxy resin obtained in each example and the characteristics of the conventional example described above are summarized in Tables 1 and 2 below.

Example 1 An eboxy resin varnish was produced by weighing and mixing the various components shown below in their respective proportions.

Ingredients Parts by Weight Solid Poke Fence Gungumo} 45-87 Liquid Epoxy Resin Butyl Cellosolve 10-45 Imitasol
Yaki} 3-10 Dicyandiamide This epoxy resin varnish has excellent adhesion and covering power,
It also has excellent chemical resistance, physical strength, and fin comfort.
It is extremely excellent as a raw material varnish for various permanent paints and inks that require these properties.

Its viscosity is 50-15 cape oise (visco tester, 20
℃). Example 2 The components shown below were weighed out and mixed, and each component was uniformly dispersed to produce an epoxy resin varnish.

/ Ingredients Parts by weight Solid punch fence 6 Float 5 Liquid epoxy resin diacetone alcohol 】○, 45 Izasol
scale willow 9 side dicyandiamide glycidyl able 2~10
This epoxy resin varnish has excellent adhesion and covering power,
Furthermore, it has excellent cold resistance, physical strength, and texture, making it an excellent varnish for various permanent paints and ink raw materials that require these properties.

Viscosity is 50 to 12 oise (viscotes, 2 pi C)
It is. Example 3 The various components shown below were weighed and mixed to uniformly disperse each component to produce a coating ink in which an extender pigment was added to an epoxy resin varnish.

Ingredients Parts by weight: Innocent Washiaki Sarin Library Yaman Misaki 7 Diacetone Alcohol 10Y45
95-70 imidaso/one root trimellitate extender pigment
5-300 This coating ink has excellent adhesion and covering power, as well as chemical resistance, physical strength, and electrical properties, and is useful as a solder resist ink for various printed wiring boards and plating resistance, as well as as an ink for anti-migration films. It is extremely excellent.

The viscosity is 60 to 18 oise (Pisco tester, 2 pi 0
). Example 4 The components shown below were weighed and mixed to uniformly disperse each component to produce a coating ink in which an extender pigment was added to an epoxy resin varnish.

0 Ingredients Parts by weight Agricultural sea bream summer and staff side 7 Cellosol acetate 1, 451-cyanoethisole-2 Undeci 84.68L, Misaki ~ Shii 1} 3 small 99ri8 Dicyandiamide 1~
9 Extender Pigments 5-30' Colored Pigments]-2 This coating ink is suitable as a paint for solder resists, migration prevention, plating resists, and chemical resistance.

What is the viscosity? 0-18 cape oise (Viscotesta, 20℃)
It is. Example 5 The components shown below were weighed and mixed, and each component was uniformly dispersed to produce a coating ink in which an extender pigment was added to an epoxy resin varnish.

Ingredients by weight: Pork, Seaman General, Side 79 Willow Cyclohexane] 0-45 ；Jichi evening; Dotori side station.

G○T 2～108
- Extender Pigment I30J This coating ink has excellent adhesion, covering power, chemical resistance, heat resistance, physical strength, and electrical properties, and is used as a solder resist ink for various printed wiring boards and plating resistance, as well as for migration * It is extremely excellent as an ink for anti-foam coatings.

Viscosity is 60-15 oise (Viscotesta, 20℃)
It is. Example 6 The components shown below were weighed and mixed, and each component was uniformly dispersed to produce a coating ink in which an extender pigment was added to an epoxy resin varnish.

Ingredients, children. Solid engineering pokie fence head group total of 4 liquid epoxy resin Tetralin 10
~45 to 98902,4-diamino-6-[2'
-Methyl iglycidyl ether
2~]0/Constitution Pigment
Fu30 color pigment
1-2 This coating ink is suitable as a paint for solder resist, migration prevention, plating resist, and chemical resistance.

The viscosity/viscosity is 80 to 17 oise (visco testa, 2 pi C)
). Table (a) Table 2 The marks 1 and 2 above are determined based on the following conditions.

Pot life: The time required (days) for the viscosity to reach twice its initial viscosity after being released in a 20qo greenhouse. Curing time: 1
Time (minutes) required for curing in a 5-inch hot air dryer.

Heat resistance: presence or absence of peeling when a peel test was performed using adhesive tape after immersing the sample in a 26-pin solder bath between three baits and sand.

If it does not peel off, mark it as ○, and if it does, mark it as ×. Plating resistance:
The time (minutes) that can withstand the above tape test when placed in a plating grade of 70qo and pH 12.5.

Acid resistance: Results obtained by immersion in 25% HCI solution for 4 hours and then performing the tape test as described above.

Migration resistance: Ag ink was applied on the coating film in a gap of 50 mm with 3 widths, 40°C, 90°C.
%R. The time required for the resistance value to be halved when DCIOOV is applied in a sunny atmosphere. Line thickness: 20
Hand-printed with a pattern of 1 rib in 0 mesh, 15
Changes in the pattern after curing at 0qo (left and right direction)
(sail).

Insulation resistance: GI of comb-shaped counter electrode by steel foil etching
Created on a fine substrate (1 gap, 150 ribs effective length), and applied 200% varnish or coating 4 ink on it.
Resistance value (Q) after printing with a mesh screen and curing.

Hardness: The hardness of a pencil that cannot be scratched when drawing a line with a pencil.

Plate cleanability: Possibility of cleaning the screen with triclean.

If it is possible, mark it with ○, if it is not possible, mark it with ×. Edge breakage: The coating film on the periphery of a 300 x 20 full surface print on a CCL substrate after coating and etching to a thickness of 35 mm.

If it is good, it is indicated by ○, and if it is bad, it is indicated by ×. Bleeding: A state in which resin oozes out around the cured film.

If not, mark it with ○, if there is, mark it with ×. As shown in the above-mentioned tables, it can be seen that according to the present invention, a varnish exhibiting excellent properties not seen in conventional products in all items and a coating ink using the varnish can be obtained.

In particular, it has a long pot life of 80 days or more, a short curing time of 6 minutes or less, a long plating resistance of 7 hours or more, a long migration resistance of 90 hours or more, and wire thickening. The insulation resistance is as low as 0.1 or less, and the insulation resistance is high at 1 and 4 to 1 and 20 before and after the life test, respectively.
It is clear that it is excellent in plating resistance, migration prevention, and solder resist ink, as the hardness is fine and hard after 7 days after plating. moreover,
Even if a solder resist ink is prepared by adding 5 to 3 parts by weight of an extender pigment to 95 to 7 parts by weight of the above-mentioned epoxy resin varnish, or even if 1 to 2 parts by weight of a coloring pigment is added, Addition of 2 to 1 part by weight of a luether concession does not improve these properties in the slightest.

In addition, the ratio of solid and liquid epoxy resin is 6:4 ~
The reason for setting the ratio to 95:0.5 is that if the ratio of solid epoxy resin increases more than this, the heat-resistant plug and plating resistance will be affected.
In addition, if the amount decreases, bleeding will occur after printing and migration resistance will deteriorate.

If the solvent content is less than 1 part by weight, the viscosity will be too high and printing workability will deteriorate, and if it exceeds 45 parts by weight, heat resistance will be impaired.

Furthermore, if the imidazole derivative and dicyandiamide have more imidazole bases, the curing will be too long, causing a problem with the heat resistance during multiple tests expected in the printed circuit manufacturing process, and if there are fewer, curing will be suppressed. It takes time to harden. If the amount of curing agent is 3 to 1 pupil, the above characteristics will be reproduced, but if it is less, the curing will be insufficient, and the heat resistance, plating resistance, hardness, etc. will be insufficient, and if it is too much, the pot life will be shortened. However, if the extender pigment is a commonly used inorganic pigment, it does not matter the type, but if it is less than 5 parts by weight, the heat resistance and thixotropy will be poor and bleeding will occur. If the epoxy resin varnish is more than 1 part by weight, the viscosity increases too much and printing workability suffers.The epoxy resin varnish according to the present invention does not lose its properties by adding extender pigments and coloring pigments as shown in the examples. Not only that, but its properties do not deteriorate even when a wide variety of common metals, carbon, etc. are added to it, and it has practical value as a raw material varnish for resistors, lead pastes, etc.

In addition, the epoxy resin varnish of the present invention has strong adhesion and adhesion to various insulating resin plates, metals such as copper, and films, and is also flexible; in particular, varnishes containing glycidyl ether are flexible. Because of its large adhesiveness, it is also useful as a raw material varnish for adhesives, flexible adhesives, flexible solder resists, etc., or as a basic composition. As explained in detail above, according to the present invention, it is possible to obtain an epoxy resin varnish having excellent plating resistance, flexibility, chemical resistance, and heat resistance.

Claims (1)

[Claims] 1 Epoxy resin 45~95 parts by weight of solid epoxy resin and 40~5 parts by weight of liquid epoxy resin
87 parts by weight, 10 to 45 parts by weight of solvent, and general formula ▲ Numerical formula, chemical formula, table, etc. ▼ (However, R_1: carbamoyl alkyl, cyanalkyl, carboxyalkyl,
carboalkoxyalkyl or diamino-S-triacylalkyl group, R_2: H atom, alkyl or aryl group, R_3: H atom or alkyl group, R_4: H atom or alkyl group) and dicyandiamide. : Hardening agent 3 included in a ratio of 1 to 1:9
An epoxy resin varnish comprising: -10 parts by weight.