JPH05125136A - Radiation-curable resin composition and screen printing ink composition for radiation-curable type strippable masking material - Google Patents

Abstract

PURPOSE:To provide the subject composition comprising two kinds of specific urethane (meth)acrylate resins, an ethylenic unsaturated group-containing compound, and a photopolymerization initiator, capable of being processed by a simple processing method not requiring a solvent, and having excellent screen printability and peelability. CONSTITUTION:The objective composition suitable for printing plate-masking materials comprises (A) an urethane (meth)acrylate resin containing a diol adipate produced from adipic acid and a diol compound such as ethylene glycol, 1,4-butanediol or neopentyl glycol, (B) an urethane (meth)acrylate resin, (C) an ethylenic unsaturated group-containing compound excluding the compounds A and B, such as 2-hydroxypropyl (meth)acrylate, and (D) a photopolymerization initiator such as triethanolamine as an arbitrary component.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation-curable resin composition and a screen-printing ink composition for a strippable masking material (hereinafter simply referred to as a composition) used in a printed wiring board containing the same.

[0002]

2. Description of the Related Art Conventionally, as a masking method in a plating process which has been used for a printed wiring board or the like, a solvent-based masking material in which an alkali-soluble synthetic resin is dissolved in an organic solvent as a binder component, An emulsified water-based masking material is used to process the wiring board, and peeling from the wiring board after plating is removed with an alkaline aqueous solution. It is possible to use a method such as cutting into pieces, and attaching and peeling them from the wiring board after plating. However, in the former method, it is necessary to remove the solvent in the masking material and an alkaline aqueous solution must be used at the time of peeling,
The latter method has a drawback that the working process is complicated in any case, such as production of an expensive mold and attachment work. In recent years, a solventless masking material using a photo-curing resin has been proposed for these methods (JP-A-59-51962, JP-A-1-141904, JP-A-1-234477). The removal of the alkaline aqueous solution does not eliminate the complexity of the process. A solventless and strippable coating material has also been proposed (JP-A-3-139573), but when used as a masking material for screen printing for a printed wiring board, it lacks suitability for screen printing, and thus the resulting coating film is obtained. There are drawbacks such as uneven surface and large foaming. As a result, the plating solution contaminates the unnecessary areas during the plating process, and the performance as a masking material cannot be recognized.

[0003]

There is a demand for a masking material which is solvent-free, has a simple processing method, is excellent in releasability, and is excellent in screen printing suitability.

[0004]

As a result of intensive studies by the present inventors in order to improve the above-mentioned problems, the present invention has been achieved. That is, the present invention

(1) Urethane (meth) acrylate resin (A) having a diol adipate consisting of diols and adipic acid, urethane (meth) acrylate resins (B) other than (A), (A) and (B) components A radiation-curable resin composition comprising a compound (C) having an ethylenically unsaturated group other than the above and a photoinitiator (D) as an optional component. (2) A radiation-curable resin composition, wherein the diols described in (1) above are ethylene glycol, diethylene glycol, 1,4-butanediol and neopentyl glycol. (3) A screen-printing ink composition for a radiation-curable strippable masking material, which may contain the radiation-curable resin composition described in (2) above and a release agent (E). (4) Urethane The mixing ratio of the urethane (meth) acrylate resin (A) in the (meth) acrylate resin is 5 to 9
The screen-printing ink composition for a radiation-curable strippable masking material according to (3) above, which is 5%. (5) A screen printing ink composition for a radiation-curable strippable masking material according to (3) or (4), wherein the release agent (E) is a dimethylpolysiloxane compound.

When the composition of the present invention is used as a UV-curable screen printing ink, it is preferable to add a photopolymerization initiator (D) which initiates or accelerates the photopolymerization reaction to the composition. Needless to say, when the composition is used as an electron beam-curable screen printing ink, the above photopolymerization initiator is unnecessary.

Specific examples of the urethane (meth) acrylate resin (A) having diol adipate used in the present invention include ethylene glycol, diethylene glycol, 1,
Polyester polyol obtained by esterification reaction of diol components of 4-butanediol and neopentyl glycol with adipic acid, hexamethylene diisocyanate, isophorone diisocyanate, tolylene diisocyanate, xylylene diisocyanate, 4, 4 '
-Organic polyisocyanates such as diphenylmethane diisocyanate and 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate,
1,4-butanediol mono (meth) acrylate, 2
Examples thereof include reaction products of hydroxyl group-containing ethylenically unsaturated compounds such as ε-caprolactone adduct of -hydroxyethyl (meth) acrylate and pentaerythritol tri (meth) acrylate. These can be used alone or in combination of two or more. The urethane (meth) acrylate resin (A) is reacted with an isocyanate group of the organic polyisocyanate, preferably 1.1 to 2.0 chemical equivalents per 1 chemical equivalent of the hydroxyl group of the polyol at a reaction temperature of preferably 70 to 90 ° C. Obtained by synthesizing a urethane oligomer, and then reacting the hydroxyl group-containing ethylenically unsaturated compounds, preferably 1 to 1.1 chemical equivalents, at a reaction temperature, preferably 70 to 90 ° C., per 1 chemical equivalent of the isocyanate group of the urethane oligomer. be able to.

Next, specific examples of the urethane (meth) acrylate resin (B) include polyols such as polycaprolactone polyol, polycarbonate diol, polytetramethylene glycol, polyester polyol other than the urethane (meth) acrylate resin (A). And these polyols and the above-mentioned urethane (meth)
It is possible to use a mixture of the polyols used for the acrylate resin (A), a reaction product of each of the organic polyisocyanates described above, and a hydroxyl group-containing ethylenically unsaturated compound such as each of the (meth) acrylates described above. Further, these reactants can be obtained by the above-mentioned method. Choleraha can be used alone or in combination of two or more kinds.

The mixing ratio of the urethane (meth) acrylate resin (A) in the total urethane (meth) acrylate resin in the composition is 5 to 95% (part by weight), preferably 10 to 45% ( Parts by weight). If it is less than this, the printability is insufficient, and if it is more than this, the physical properties of the film are weakened and the coating film is damaged at the time of peeling, so that it is not suitable as a masking material. The total of the components (A) and (B) is preferably in the range of 60 to 80% (parts by weight) of the total composition.

Specific examples of the ethylenically unsaturated group-containing compound (C) other than the components (A) and (B) used in the present invention include, for example, 2-ethylhexyl as the monofunctional ethylenically unsaturated group-containing compound. Acrylate, 2-hydroxypropyl (meth) acrylate, ethylcarbitol acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentanyloxyethyl (meth) acrylate, phenoxyethyl (meth) acrylate, nonyl Phenoxyethyl (meth) acrylate, lauryl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, diethylene glycol (2-ethylhexyl) ether (meth) acrylate, phenylglycidyl ether (meth) There are acrylate, acryloylmorpholine and the like, and as the bifunctional ethylenically unsaturated group-containing compound, 1,6-hexanediol di (meth) acrylate, ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, neopentyl glycol. Alkylene glycol di (meth) acrylates such as di (meth) acrylate, polyethylene glycol di (meth) acrylates such as triethylene di (meth) acrylate, tripropylene di (meth) acrylate, polypropylene glycol di (meth) acrylate
Epoxy di (meth) s such as acrylates, di (meth) acrylates of alkylene oxide adducts of bisphenol A or hydrogenated bisphenol A, ethylene glycol diglycidyl ether di (meth) acrylate, propylene glycol diglycidyl ether di (meth) acrylate Acrylates and the like can be mentioned. These can be used alone or in combination of two or more. Examples of preferred ethylenically unsaturated group-containing compound (C) include 2-hydroxypropyl (meth) acrylate, phenylglycidyl ether (meth) acrylate, acryloylmorpholine, and tetraethoxydiacrylate of bisphenol A.

The composition ratio of the ethylenically unsaturated group-containing compound (C) other than the components (A) and (B) used in the present invention in the total composition is 5 to 50% (parts by weight), preferably 10
˜30% (part by weight ratio). If the ratio is less than this range, the viscosity of the composition is high and it is not preferable for printability. If the ratio is more than this range, the cured product has poor film properties and poor releasability, which is not preferable as a masking material.

When the composition according to the present invention is photopolymerized by irradiation with ultraviolet rays or the like, it is preferable to use a photopolymerization initiator (D) which absorbs light energy to generate radicals. Examples of the photopolymerization initiator include acetophenones, benzophenones, Michler's ketones, benzyl, benzoin alkyl ether, benzyl dimethyl ketal, carbonyl compounds such as benzoyl benzoate, thioxanthones, and sulfur compounds such as tetramethylthylium mosulfite. And so on. These can be used alone or in combination of two or more. Further, such a photopolymerization initiator (D) is, for example, an amine compound such as triethanolamine, P-dimethylaminobenzoic acid isoamyl ester, N, N-diethyl-P-aminobenzonitrile, or the like,
Known and commonly used photosensitizers such as phosphorus compounds such as tri-n-butylphosphine and chlorine compounds such as hexachloroethane can be used alone or in combination of two or more kinds. These can be used alone or in combination of two or more. The mixing ratio of the photopolymerization initiator (D) and the photosensitizer is preferably 1 to 25 parts by weight with respect to 100 parts by weight of the composition. If the amount is less than this, the polymerization reaction does not sufficiently occur even when irradiated with ultraviolet rays, and the physical properties of the film are lacking. If it is too large, no particularly beneficial effect can be obtained. When the composition is cured by electron beam, the photopolymerization initiator (D) is unnecessary.

In the present invention, the release agent (E) can be used. Specific examples of the organopolysiloxane compound include silicone oils such as dimethylpolysiloxane, methylhydrogenpolysiloxane and methylphenylpolysiloxane, Examples include modified silicone oils modified with alkyl, amino, epoxy, fluorine, carboxyl, alcohol, mercapto, and silicone macromonomers having a polymerizable functional group at one or both ends of the molecular chain. .. Examples of preferable organopolysiloxane compounds include alcohol-modified silicone oil, alkyl-modified silicone oil, and silicone macromonomer having a (meth) acryloyl group at one end-polymerizable functional group of the molecular chain. These known and commonly used organopolysiloxane compounds may be used alone or in combination of two or more. These may be used in an amount of 1 to 10 parts by weight, preferably 1 to 4 parts by weight, based on 100 parts by weight of the composition. If it is less than this range, the releasability is poor, and if it is too large, the adhesion to the printed wiring board is poor and the performance as a masking material is lacking.

The composition of the present invention comprises dyes and pigments other than the above components,
Antifoaming agents, leveling agents, light stabilizers (eg hindered amines), antioxidants, polymerization inhibitors, antistatic agents, metal soaps such as zinc stearate, fillers such as calcium carbonate and colloidal silica, etc. may be used in combination. it can.
The radiation-curable resin composition and the radiation-curable strippable masking material composition for screen-printing ink (collectively referred to as the composition) of the present invention can be obtained by mixing and dissolving each component. To cure the resin composition of the present invention with an electron beam, for example, 100 to 5000e
It is preferable to use an electron beam accelerator capable of irradiating V energy. Further, in order to cure the resin composition of the present invention with ultraviolet rays, an ultraviolet irradiation device having, for example, a xenon lamp, a high pressure mercury lamp or a metal halide lamp as a light source is used. When a high pressure mercury lamp is used, it can be irradiated with ultraviolet rays to be cured by a lamp having a light amount of 80 to 120 W / cm. Needless to say, the resin composition of the present invention exhibits extremely high thixotropy and is useful for screen printing suitability, but it is also useful for various coating methods, potting methods and the like.

[0014]

EXAMPLES Next, the present invention will be described more specifically by way of examples. The evaluation in the examples was performed by the following methods. In addition, the part in an Example shows a weight part. (1) Printability: The printability was evaluated by printing on a printed board formed on a polyimide substrate using a plate-made 70-mesh polyester screen and a urethane rubber squeegee having a Shore hardness of 60 degrees. Printing machine: Minomat Y-40 (Mino Group Co., Ltd.) ○ ─── Good with no bubbles on the coating surface △ ─── Slight bubbles on the coating surface × ─── Many bubbles on the coating surface ( 2) Peelability: Difficulty in peeling the cured coating film from the printed board ○ ── Good peeling from the printed board △ ───Slightly difficult peeled from the printed board × ───Peeled from the printed board It is difficult to break the membrane. (3) Thixo ratio: The viscosity of the composition was measured using an R-type viscometer (measured at 25 ° C., 10 rotations, 100 rotations. 10 rotations /
100 rotations was used as a thixo ratio) Synthesis example of urethane (meth) acrylate resin (A)

Synthesis Example 1 Polyester diol of 1,4-butanediol and adipic acid (hydroxyl value 55.9 mgKOH / g) 401.5
And 67.2 parts of hexamethylene diisocyanate were charged, and the temperature was raised and the reaction was carried out at 80 ° C. for 10 hours. Next, after charging 46.4 parts of 2-hydroxyethyl acrylate and 0.26 part of methquinone and reacting again at 80 ° C. for 10 hours, 0.13 parts of di-n-butyltin dilaurate was charged and further reacting at 80 ° C. for 2 hours. To obtain urethane acrylate.

Synthesis Example 2 Polyester diol of ethylene glycol and adipic acid (hydroxyl value 56.1 mg KOH / g) 400.0 parts,
Charge 52.2 parts of tolylene diisocyanate and raise the temperature to 8
The reaction was carried out at 0 ° C for 10 hours. Then, 23.2 parts of 2-hydroxyethyl acrylate and 0.24 part of methquinone were charged and reacted again at 80 ° C. for 10 hours, then 0.12 parts of di-n-butyltin dilaurate was charged and further reacted at 80 ° C. for 2 hours. To obtain urethane acrylate.

Synthesis Example 3 Polyethylene diol of diethylene glycol and adipic acid (hydroxyl value 56.7 mg KOH / g) 359.8
And 67.2 parts of hexamethylene diisocyanate were charged, and the temperature was raised and the reaction was carried out at 80 ° C. for 10 hours. Next, after charging 46.4 parts of 2-hydroxyethyl acrylate and 0.24 part of metoquinone and reacting again at 80 ° C for 10 hours, 0.12 parts of di-n-butyltin dilaurate was charged and further reacted at 80 ° C for 2 hours. To obtain urethane acrylate.

Synthesis Example 4 Polyester diol of neopentyl glycol and adipic acid (hydroxyl value 55.7 mg KOH / g) 402.9
And 69.6 parts of tolylene diisocyanate were charged, the temperature was raised, and the mixture was reacted at 80 ° C. for 10 hours. Then, 46.4 parts of 2-hydroxyethyl acrylate and 0.24 part of methoquinone were charged, the mixture was reacted again at 80 ° C. for 10 hours, and then 0.12 part of di-n-butyltin dilaurate was charged, and further 80 parts were added.
A urethane acrylate was obtained by reacting at 2 ° C. for 2 hours. Synthesis example of urethane (meth) acrylate resin (B) other than urethane (meth) acrylate resin (A)

Synthesis Example 5 23.7 parts of neopentyl glycol, polytetramethylene glycol (hydroxyl value 56.3 mg KOH / g) 24
4.2 parts and isophorone diisocyanate 155.5 parts were charged, and the temperature was raised and the reaction was carried out at 80 ° C. for 10 hours. Next, 81.3 parts of 2-hydroxyethyl acrylate and 0.25 parts of methoquinone were charged, the mixture was reacted again at 80 ° C. for 10 hours, 0.13 parts of di-n-butyltin dilaurate was charged, and further reacted at 80 ° C. for 2 hours. To obtain urethane acrylate.

Synthesis Example 6 Neopentyl glycol adipate (hydroxyl value 233.
8 mgKOH / g) 233.8, polytetramethylene glycol (hydroxyl value 56.3 mgKOH / g) 139.
5 parts and 154.8 parts of isophorone diisocyanate were charged, the temperature was raised, and the reaction was carried out at 80 ° C. for 10 hours. Next, 32.3 parts of 2-hydroxyethyl acrylate and 0.26 part of methquinone were charged and reacted again at 80 ° C. for 10 hours, then 0.13 parts of di-n-butyltin dilaurate was charged and further reacted at 80 ° C. for 2 hours. To obtain urethane acrylate.

Synthesis Example 7 Poly-ε-caprolactone type polyol (hydroxyl value 21
(3.7 mg KOH / g) 525.1 parts and isophorone diisocyanate 333.5 parts were charged, and the temperature was raised to 80 ° C. for 13
Reacted for hours. Next, 119.5 parts of 2-hydroxyethyl acrylate and 0.49 part of methquinone were charged and reacted again at 80 ° C. for 10 hours, followed by dilauric acid di-n.
-Butyltin (0.13 parts) was charged and further reacted at 80 ° C for 2 hours to obtain a urethane acrylate.

Examples 1 to 8 and Comparative Examples 1 to 2 Screen printing inks for UV-curable strippable masking materials having the compositions shown in Table 1 were prepared and screen-printed on a printed wiring board, and then ultraviolet rays or electron beams were used. Was radiated to cure the ink for masking. still,
Both examples are CI No, PIGMENT BLUE6
0.2% of 4 was added to obtain a blue ink. The amount of printing ink applied was adjusted so that the film thickness when dried was 70 μm. Examples 1 to 5 and 7 were irradiated with ultraviolet rays, and Examples 6 and 8 were irradiated with electron beams. The irradiation method was as follows. Ultraviolet irradiation: An ultraviolet irradiation device (GS ASE-20, manufactured by Nippon Battery Co., Ltd.) having a high pressure mercury lamp of 80 W / cm was used to perform irradiation twice at a conveying speed of 20 m / min to cure the composition. Electron beam irradiation; electron beam curing device having an irradiation amount of 60 Mrad (CB 175/15/18, manufactured by Eye Graphic Co., Ltd.)
It was cured by irradiating it twice at a transportation speed of 20 m / min.

Table 1 Component Example Comparative Example 1 2 3 4 5 6 7 8 1 2 (A) Synthesis Example 1 20 15 10 20 Compound Synthesis Example 2 15 30 10 10 Compound Synthesis Example 3 30 Compound Synthesis Example 4 33 Compound ( B) Synthesis Example 5 55 65 30 50 Compound Synthesis Example 6 55 40 40 10 45 20 50 Compound Synthesis Example 7 10 42 20 Compound (C) R-128 * 1 15 15 10 20 20 10 20 20 2-HPMA * 1 10 15 10 20 10 10 5 10 20 R-551 * 2 10 10 5 10 (D) Ir-184 * 3 3 3 3 3 3 3 3 3 (E) SF-843 * 4 3 3 3 3 3 3 3 3 3 3 (F) Sterianric acid 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Zinc printability ○ ○ ○ ○ ○ ○ ○ ○ × × Peelability ○ ○ ○ ○ ○ ○ ○ ○ × × Thixotropic property 1.34 1.28 1.32 1.37 1.29 1.36 1.22 1.21 1.02 1.02

Note * 1 R-128: KAYARAD R-128 manufactured by Nippon Kayaku Co., Ltd., phenylglycidyl ete acrylate * 2 R-551: KAYARAD R-551 manufactured by Nippon Kayaku Co., Ltd., bisphenol A tetratoxodiacrylate * 3 Ir-184: Irgacure 184 manufactured by Ciba Geigy, photopolymerization initiator * 4 SF-8416: Toray Dow Corning, alkyl-modified silicone oil

As is clear from the evaluation results in Table 1, the screen printing ink composition for strippable masking materials of the present invention is excellent in printability and releasability.

[0024]

The screen printing ink composition for a strippable masking material of the present invention has a simple processing method, is excellent in printing suitability and is excellent in peelability, and is suitable for a masking material for a printed board.

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Claims (5)

[Claims] 1. A urethane (meth) acrylate resin (A) having a diol adipate composed of diols and adipic acid, and a urethane (meth) acrylate resin (B) other than (A), components (A) and (B). A radiation-curable resin composition, comprising the ethylenically unsaturated group-containing compound (C), and a photopolymerization initiator (D) as an optional component. 2. The radiation curable resin composition according to claim 1, wherein the diols are ethylene glycol, diethylene glycol, 1,4 butanediol and neopentyl glycol. 3. A screen-printing ink composition for a radiation-curable strippable masking material, which may contain the radiation-curable resin composition according to claim 1 and a release agent (E). 4. The mixture ratio of the urethane (meth) acrylate resin (A) in the total urethane (meth) acrylate resin in the composition is 5 to 95%. A radiation-curable screen printing ink composition for strippable masking materials. 5. The radiation-curable screen printing ink composition for a strippable masking material according to claim 3, wherein the release agent (E) is an organopolysiloxane compound.