JPS603624A - Photosensitive composition - Google Patents

Abstract

PURPOSE:To obtain an alkali-soluble ultraviolet-curing photosensitive composition emitting hardly a foul odor, undergoing little change with the lapse of time, and having superior acid resistance by mixing novolak resin having low mol.wt. with a compound having an alcoholic hydroxyl group and a polymerizable double bond and a photopolymn. initiator. CONSTITUTION:Novolak resin (A) having <=2,000mol.wt. such as phenol resin or cresol resin is mixed with a compound (B) having at least one alcoholic hydroxyl group and one polymerizable double bond in the molecule such as 2-hydroxymethyl acrylate or diethylene glycol monoacrylate and a photopolymn. initiator (C) such as benzoin or benzophenone to obtain the desired photosensitive composition. This composition is suitable for use as an etching resist, a plating resist and filling ink, and it is widely applied by making use of the superior acid resistance and solubility in alkali.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ink composition used as an etching resist, a metskire resist, and a hole-filling ink, and particularly to a photosensitive ink composition that is cured by ultraviolet irradiation and whose cured coating film can be dissolved and removed by an aqueous alkaline solution. .

In the manufacturing process of printed circuit boards and partially plated products, a film-formable mark is printed on the substrate (copper-clad laminate) or plated product as an etching resist or metal resist using methods such as screen printing or offset printing to produce the desired results. Pattern *i'; after forming a film, it is immersed in an acidic etching solution or plating solution, and no coating film is formed; exposure 7;
An operation 7c is performed in which the ts portion is etched or plated, and then the coating film is removed by immersion in an alkaline aqueous solution. Therefore, the ink of this strain must be acidic as a coating film,
It is required that the coating film can be removed to 1rzIJH with an alkaline aqueous solution. Ink +i:i, which has conventionally been used for etching resists, is known to be prepared by dissolving alkaline resins such as rosin, maleic denatured rosin, and phenolic noselac resins in solvents. It is being These resists form a coating film by volatilizing a solvent, and are generally called heat-drying etching resists. Although this type of etching resist has relatively good resolution, its lead shielding hardness is as low as HB or less, so it is easily scratched during the printed circuit board processing process, and is therefore prone to disconnection defects. In addition, during the printing process, the solvent in the ink evaporates and dryness increases, and in the case of screen printing, the screen dries and becomes clogged, causing pinholes and scratches in the printed pattern, making it difficult to see clear circuit patterns. is difficult to obtain.

Furthermore, in order to obtain a cured coating film, drying at 80° C. for about 3 to 5 minutes is required, which leaves problems such as energy loss, the risk of ignition by the solvent, and environmental pollution. In order to eliminate these drawbacks, a snow line hardening type ink has recently been proposed (Japanese Patent Application Laid-Open No. 56-8417+1).

However, since the proposed ink composition uses a styrene-maleic acid copolymer, it not only has a strong odor, but also causes strong irritation to the mucous membranes of the eyes, nose, etc., and is therefore undesirable. In addition, there are also drawbacks such as changes in the viscosity of the ink over time, and depending on the curing conditions, the solubility of the cured coating film in an alkaline aqueous solution decreases, resulting in peeling due to one shadow, so that it is not fully satisfactory.

The purpose of the present invention is to provide a material with little odor and irritation to mucous membranes, little change in ink characteristics over time and changes in coating film characteristics due to curing conditions, excellent acid resistance, and good printing characteristics.
Another object of the present invention is to provide an alkali-soluble ultraviolet curable photosensitive ink composition capable of forming a hardened coating film with high hardness.

The photosensitive composition of the present invention comprises (a) a Nozelac resin having a molecular weight of 2,000 or less; (b) a compound having at least one alcoholic hydroxyl group and one polymerizable double bond in the molecule; It is characterized in that it is cured by ultraviolet rays and that the cured portion is soluble in aqueous alkali.

Since the photosensitive composition of the present invention has a cured fallen film that has excellent resistance to scratching and is soluble in alkali, it can be used not only as an etching resist, as a masking resist, and as a hole-filling ink, but also as an easy-to-use material. 1Z, Mi m:';+.

It can be applied to any application that utilizes the characteristics of

Novolak aJ of (a) used in the present invention ]i'J
refers to aqueous alkali-soluble phenolic resins, cresol resins, and alkylphenol resins (fats).If the molecular weight is 2,000 or more, curing will be poor, so a molecular weight of 2,000 or less is preferable.

Compounds having at least one alcoholic hydroxyl group and one double bond in the molecule of (b) include 2-hydroxymethacrylate, 2-hydroxyethyl acrylate, 2-human 90xypropyl acrylate, 3- Hydroxypropyl acrylate, 2-hydroxy-3-
Mention may be made of chloropropyl acrylate, 2-hydroxybutyl acrylate, diethylene glycol heptanoacrylate and their corresponding butane 1) acrylates. It is preferable for the additive stitch to have a weight of 20 to 70 wt relative to the component (a). Box (has poor arsenic resistance, and l104 etching resistance of the cured coating is 8X-.

Next, as the photopolymerization initiator (c), α-alcohols such as pentuin, butyroin, acetoin, etc.;
Benzoin methyl ni-thyl, benzoin ethyl ether, penzoin inf'robyl ether, penzoin isof'thyl ether, bivaloin ethyl ether, etc. Noacyloin ethers; diacetyl, dipenso-9yl, diphenyl ketone, phenylglyoxal, 2.3-penmedione, 1- Phenylbutane-1,2-dione, 2
Adjacent polyketone compounds such as , 3-octadione, diphenyltriketone; benzophenone, 'ω-bromoacetophenone, 2-hydroxy-2-methylpropiophenone, 4'-isopropyl-2-hydroxy-2-methylpropiophenone , 2,2-dimethoxy-2-phenylacetophenone, p-tert-butyltrichloroacetophenone, p-tart-butylmonochloroacetophenone, 2, 2'-jethoxyacetophenone, 4, 4'-bis-dialkylaminobenzophenone, 2, Phenone 'fA% such as 2-dimethoxy-2-phenylacetophenone is obtained for 2 h.

The exact proportions of the three components (a), (b), and (C) above vary slightly depending on the purpose of use, but for the (a) component, it is 30 to 70 wt relative to the bl component; For component (a), 30 to 70 wL, 4,
For component (c), 2 to 15 wt, % is appropriate for the total weight of (al + (b)).
If t is 4 or more, the curing speed becomes slow or internal curing failure occurs, resulting in insufficient chemical resistance. Furthermore, if the ratio of the c1 component is less than 2 wt 0%, the curing speed will be slow and internal curing will be poor, resulting in poor chemical resistance of the coating film.

On the other hand, if the proportion of component (c) is 15% or more, no improvement in properties is observed and it is uneconomical.

The composition of the present invention contains various additives commonly used in this field, such as modifiers, viscosity modifiers, alkali removal promoters,
Fillers, thixotropic agents, leveling agents, colorants, thermal polymerization inhibitors, antifoaming agents, etc. can be added.

Examples of the modifier include xylene resin, rosin, rosin modified resin, acrylic copolymer, and styrene-maleic acid copolymer. The amount used is 1 to 30 for composition I snout.
wt, 4, and is added mainly for the same purposes as the above, such as film adhesion, leveling, and chemical resistance.

Examples of the viscosity MLf4 modifier include methoxyethyl acrylate, ethoxyethyl acrylate, methoxyethyl acrylate, methoxyethyl acrylate, tetrahydroacrylate, benzyl acrylate, phenoxyethyl acrylate, cyclohexyl acrylate, carpitol acrylate, and methacrylates corresponding to these. The amount of these used is usually 20 wt.4 or less relative to the composition. As alkali removal accelerators and coating film hardness improvers, itaco/■♀, methylhexahydrophthalic acid, 3-methyltetrahydrophthalic acid, 4-
Methyltetrahydrophthalic acid and its acid anhydrides and 2-hydroxyethyl acrylate (or methacrylate) or 2-hydroxyethyl acrylate (or methacrylate), etc., at least one in the molecule Examples include monoesterified products formed with a compound having an alcoholic hydroxyl group and one polymerizable double bond. The amount of these used is usually 40 wt, 4 or less based on the composition.

Examples of fillers include Merck, barium sulfate, clay, and silica. The amount of these used is usually 1 to 5 based on the composition.
0 wt, %.

As thixotropic agents, Aerosilna 100, Aerosil ≠ 200, Aerosil R-972 (Nippon Aerosil Co., Ltd. iAA) silica-based compounds and Organai) A
There are organic base complexes of montmorinite such as (manufactured by Toyojun Yoko Co., Ltd.). The amount of these used is usually 1 to 5% by weight based on the composition.

Examples of colorants include phthalocyanine-based pigments, threne-based pigments, and dyes such as methyl violet and methylene blue. The amount of these used is usually 02 to 3 wt-% based on the composition.
It is.

Examples of the SXCXC mixture inhibitor include nohydroquinone, p-methoxyphenol, cuprous chloride, and naphthylamine.

The amount of these used is usually 0.001 to 0.1 based on the composition.
wt, I'm in charge.

As an antifoaming agent, TSA-720, TSA-750゜Y
There are silicone antifoaming agents such as SA-02 (manufactured by Toshiba Silicon Co., Ltd.) and fluorine surfactants. The amount of these used is typically 0.5-2% by weight based on the composition.

The present invention will now be explained in more detail by way of examples.

Synthesis of phenolic nose resin: Phenols 50 50 Formalin 47 47 Oxalic acid 1.3 1.8 Hydrochloric acid 1.2 i, 2 Production method: Mass phenols, formalin' and f^FIZ are charged in a reactor, React for 60 minutes at reflux temperature, then add hydrochloric acid and condense for a further 35 minutes.

The reaction is stopped by adding a large amount of cold water, and the mixture is left to stand for 30 minutes. Next, dehydration is performed under reduced pressure, and then the resin liquid obtained is poured into a container to solidify.

Example 1 A photosensitive composition having the following treatment was prepared.

Noenol novolac resin (synthesis example 2) 30wt, %
2-Hydroxyethyl methacrylate 30 Phthalocyanine blue-○, 5 wt, qb2-hydroxy-2
-Methylpropiophenone 3 Barium sulfate 36
．． 5 tt Ratio Example 1 A photosensitive composition was prepared in Example 1 and 2 except that only 2-hydroxyethyl methacrylate was replaced with carpitol acrylate.

Comparative Example 2 A photosensitive composition was prepared in accordance with Example 2 except that only 2-hydroxyethyl methacrylate was replaced with 1,3-pukundiol acrylate.

Example 2 A photosensitive composition having the following treatment was prepared.

Phenol novolak resin (synthesis example 1) 20wt, 4
2-memecloxyethyl acit'-+nahydrophthalate 10 2-hydroxypropyl acrylate
40 〃Phthalocyanine Blue 0.5〃 2.2-Jethoxyacetophenone 5 〃Modaflow (Belink agent manufactured by Monsanto) 3, tt silica
24.5 7/ Comparative Example 3 A photosensitive composition was prepared in Example 2 except that only 2-hydroxypropyl methacrylate was replaced with benzyl acrylate.

Comparative Example 4 A photosensitive composition was prepared in Example 2 except that only 2-hydroxypropyl methacrylate was replaced with tetraethylene glycol.

Next, the above photosensitive composition was applied as an ink to a seedling (T') copper-clad laminate by screen printing to a film thickness of 20 μnL, and this was applied using an ozone-less concentrating high-pressure mercury lamp of 80 W/cIrL. ” 16j 1!:'ii Nyx j:ilJ at a speed of sm/min in a UV curing oven
Is it irradiated with ultraviolet rays at an irradiation distance of 10 CrIL?
The film is cured and the cured film is treated with lead”ill.
4 Qi,! p:,'l, alkaline bath dissolution and etching resistance test J6.

The photosensitive compositions (inks) were also tested for stability (A', +). These test methods are as follows.

Pencil hardness: Place a commercially available pencil (Uni manufactured by Mitsubishi Pencil Co., Ltd.) on the paint film of a cured paint film sample, apply a 1-Yu load on it, and measure the hardness when the paint film is scratched. .

Alkali solubility: Spray 39g of sodium hydroxide onto the coating surface of a cured coating sample and measure the time until the coating dissolves.

Etching liquid resistance: cuprous chloride 40wt, hydrochloric acid 10wt, water 5wt
A specimen of the cured coating film was immersed in an etching solution of 0 wt% at 50° C. for 30 minutes, and the condition of the coating film was visually observed.

Storage stability: 50 g of the photosensitive composition is placed in a 50 cc brown plastic container and left in a constant temperature bath at 70° C. to allow time for the composition to gel.

The test results are shown in the table below.

Claims (1)

[Scope of Claims] 1. (a) Nozerak resin having a molecular weight of 2000 or less and (
b) At least one alcoholic hydroxyl group and one
A photosensitive composition containing as main components a compound having 1 or more polymerizable double bonds and (e) a photopolymerization initiator. 2. The composition according to claim 1, wherein the photo-initiator is a funinone type.