JPS6346791B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ultraviolet curable printed circuit board solder resist ink composition, and particularly relates to an ultraviolet curable printed circuit board solder resist ink composition, which is particularly suitable for direct printing or offset printing of a solder resist pattern on a printed circuit board on which circuits are formed using a dry planographic printing plate. The present invention relates to a possible solder resist ink composition.

Currently, there are two methods of forming patterns using solder resist ink for use in printed circuit boards: screen printing and photoprinting. Of these two methods, the former has high productivity and is inexpensive, but it has problems with printing accuracy and reproducibility, and the maximum width that can be printed is 0.2 mm, while the latter has low accuracy and reproducibility. The actual situation is that its use is limited because of its low productivity and the high cost of photoresists.

Ink compositions for dry lithography are known per se (for example, Japanese Patent Publication No. 52-125010 and Japanese Patent Publication No. 54-121807).
(Refer to the above publications, etc.), but no ink has yet been proposed that can be used as a solder resist ink in the production of printed circuit boards.

Currently commercially available dry lithographic inks for paper and metal (oxidative polymerization type and ultraviolet curing type) may be used to print on printed circuit boards without causing scumming. These inks are unsuitable as solder resist inks for printed circuit boards because they have low heat resistance, low soldering heat resistance, low solvent resistance, low pencil hardness, and poor electrical properties.

On the other hand, the ultraviolet curable solder resist ink used in silk screen printing contains prepolymers such as urethane acrylate, silicone acrylate, and epoxy acrylate as the main film-forming components. When dry lithographic printing is performed using the manufactured lithographic ink, scumming occurs in non-image areas and the printing durability of the printing plate is impaired, making it unusable.

Thus, the object of the present invention is to enable printing without causing background stains in non-print areas, and to provide a cured film that has excellent heat resistance, soldering heat resistance, solvent resistance, and pencil hardness, and is electrically resistant. An object of the present invention is to provide an ultraviolet curable solder resist ink composition for dry lithography, which has good properties.

According to the present invention, the above object is achieved by adding 10 to 80 parts by weight of an ultraviolet curable prepolymer (B) alone or in a mixture selected from urethane acrylate, silicone acrylate, polybutadiene acrylate, and epoxy acrylate; 5 to 70 parts by weight of (A) alone or as a mixture, 30 to 80 parts by weight of an organopolysiloxane, and 1 to 10 parts by weight of an aluminum chelate compound.
This is achieved by containing 60 parts by weight in 100 parts by weight of the ink.

Urethane acrylate, silicone acrylate, polybutadiene acrylate, and epoxy acrylate (B), which are components of the solder resist ink composition according to the present invention, have ultraviolet curability,
It satisfies the heat resistance, solvent resistance, chemical resistance, adhesion, and electrical properties of a solder resist ink.

In addition, a reaction product (A) of the above component (A), an organopolysiloxane, and an aluminum chelate compound
(hereinafter referred to as "Varnish A") is a varnish for the purpose of preventing background smearing during dry lithographic printing without deteriorating the properties as the solder resist ink described above, and contains 20 parts by weight of (B). If it is less than 70 parts by weight, the properties as a solder resist ink cannot be maintained, and if it is more than 70 parts by weight, scumming tends to occur. Organopolysiloxane uses its oil-repellent properties to prevent background smudges during dry lithographic printing. If it is less than 30 parts by weight, its effect against background smudges will decrease, and if it is more than 80 parts by weight, it will easily separate during printing. The ink bleeds out on the surface, reducing the transferability of the ink to the printed circuit board. In addition, the aluminum chelate compound increases the viscosity of the ink by reacting with the above components, increases the cohesive force of the ink, and prevents scumming during printing and bleed-out of the organopolysiloxane. Thickening effect decreases,
If it exceeds 10 parts by weight, it will easily gel and the cohesive force will be too high, making it difficult to form into an ink.

Varnish A is obtained by mixing the above components and heating the mixture at a temperature of 100 to 150° C. for 10 minutes to 3 hours under normal pressure.

The composition of the present invention comprises the above component (B) alone or in combination.
It is obtained by containing 10 to 80 parts by weight and 5 to 60 parts by weight of the above reaction product (A) in 100 parts by weight of the ink. At this time, if the above component (B) is less than 10 parts by weight, the properties of the solder resist cannot be satisfied.
If it exceeds 60 parts by weight, scumming tends to occur during printing.

Further, if the reaction product (A) is less than 5 parts by weight, no effect on background smear during printing can be obtained, and if it is more than 60 parts by weight, the properties as a solder resist are deteriorated.

The product name for organopolysiloxane is KR―
168, KR-211, KR214, KR-220, KR-251,
KR-280, KR-358, KR-3093, TSR-165,
Those commercially available as TSR-171, TSR-187, etc. can be used, and as aluminum chelate compounds, product names EB-2, EB-102,
MB-2, MB-12, EP-12, AIPD, AMD,
Those commercially available as ASBD, ALCH, ALCH-TF, etc. can be used.

The product name for urethane acrylate is M-
1200X, M-1100X, XP-4000B, XP-4200B,
You can use the one commercially available as XP-7000B.

Product name: X-41 for silicone acrylate
-1007A, SA-1002, etc. can be used.

As polybutadiene acrylate, R-
45ACR, etc., and as epoxy acrylate, the product names are SP-1506, SP-1507, SP-1509, VR-
Those commercially available as 60X, VR-77X, VR-90X, Sumiflash A, Sumiflash B, UE EXP-250, etc. can be used.

The solder resist ink composition according to the present invention includes a photopolymerizable monomer that also serves as a diluent, a coloring pigment, an extender pigment, a photosensitizer, and other additives such as waxes, polymerization inhibitors, thickeners, surfactants, and curing agents. It can contain accelerators (gel varnishes, amine-based and benzoic acid-based ones), ink adhesion energy reducing agents (silicone oil, etc.), and the like. Among these, photopolymerizable monomers include ethylene glycol diacrylate, ethylene glycol dimethacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate,
Neopentyl glycol diacrylate, neopentyl glycol dimethacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetraacrylate, pentaerythritol Tetramethacrylate, dipentaerythritol hexaacrylate, dipentaerythritol hexamethacrylate, β-hydroxyalkyl acrylate, β-hydroxyalkyl methacrylate, triallyl cyanurate, triallyl isocyanurate, diallyl phthalate, diallyl isophthalate, melamine acrylate, butoxyethyl acrylate , stearyl acrylate, lauryl acrylate, tetrahydroxyfurfuryl acrylate, tetrahydroxyfurfuryl methacrylate, aminoalkyl acrylate, neopentyl glycol pivalate diacrylate,
Acrylic acid esters and methacrylic acid esters such as aminoalkyl methacrylate and melamine acrylate can be used. There are no particular restrictions on the coloring pigments, but they include phthalocyanine blue, phthalocyanine green, titanium white, titanium yellow,
Carbon Black, Yellow Lead, Hansa Yellow, Benzidine Yellow, Lake Red C, Vulcan Orange, Disazo Yellow, Brilliant Carmine
Organic and inorganic pigments such as 6B, chrome vermilion, etc. can be used. As an extender pigment, barium sulfate,
Calcium carbonate, fine talc, bentonite, fine silica, clay, kaolin, fine asbestos, etc. can be used. As a photosensitizer, benzoin alkyl ether, xanthone, benzophenone, 2
-chlorothioxanthone, alkylthioxanthone, anthracene, 2,2-diethoxyacetophenone, dimethylbenzyl ketal, benzyl,
Azobisisoputyronitrile, Michler's ketone, 1-chloromethylnaphthalene, N,N-tetraethyl-4,4-diaminobenzophenone, anthraquinone, 1-chloroanthraquine, 2-ethylanthraquinone, biacetyl, 2-hydroxy-2- Methyl-propiophenone, 4'-isopropyl-2-hydroxy-2-methyl-propiophenone, etc. can be used.

When performing solder resist ink printing of printed circuit boards using the solder resist ink composition according to the method of the present invention, productivity superior to that of the screen printing method is achieved, and printing accuracy and reproducibility, which are the deficiencies of the screen printing method, are improved. Punching is possible without a guide hole since the problem of mechanical properties can be overcome.

According to a dry lithography test of a printed circuit board using the solder resist ink according to the present invention,
It was confirmed that printing accuracy and reproducibility of 0.05 mm width could be obtained, and no deviations due to expansion and contraction of the screen, which are seen when screen printing is performed, were observed. The solder resist ink according to the present invention can be used not only for rigid printed circuit boards but also for dry lithographic printing of flexible printed circuit boards.

The solder resist ink according to the present invention can be similarly used as a heat-resistant display character ink for printed circuit boards.

The invention will now be described in more detail in connection with manufacturing-printing test examples.

Manufacturing - Printing Test Example 1 a Manufacturing part by weight of varnish A Organopolysiloxane (KR-220) 50 Epoxy acrylate (SP-1509) 50 Aluminum chelate compound (MB-12) 3 The above ingredients were heated at 120°C at normal pressure. Varnish A was produced by heating with stirring for 40 minutes.

b Manufacture of solder resist ink A solder resist ink was produced by mixing and uniformly dispersing the following components in a three-roll mill in a conventional manner.

Parts by weight Epoxy acrylate (SP-1509) 40 Trimethylolpropane triacrylate 15 Polyethylene glycol diacrylate 10 Barium sulfate 20 Gel varnish 5 Phthalocyanine green 3 Benzophenone 3 Isoamyl benzoate 2 Varnish A 30 Surfactant 2 total 130 c Printing test Dry lithography The attached sheet-fed offset printing machine was loaded with the solder resist ink manufactured by the method described in item b above, and direct printing and offset printing were performed on printed circuit boards at a speed of 30 sheets/min. Each printer was able to print more than 1000 sheets in succession without any problems.

Next, the obtained printed matter was irradiated with ultraviolet light using a 5.6KW three-light type ultraviolet irradiation device with a conveyor speed of 5 m/min, and a cured coating film with a pencil hardness of 3H or higher was obtained. When immersed in 1,1,1-trichloroethane (30°C) for 1 hour, there was no blistering, discoloration, or peeling, and it was confirmed that the cured solder resist ink film had sufficient solvent resistance.

After that, the printed circuit board was floated in a 260℃ solder bath for 15 seconds. The solder coated only on the copper foil other than the printed pattern, and there was no blistering or peeling, and the cured coating of the solder resist ink had sufficient solder heat resistance. It was confirmed that it has.

Manufacturing - Printing Test Example 2 a Manufacturing part by weight of Varnish A Epoxy acrylate (VR-60X) 30 Silicone acrylate (SA-1002) 30 Organopolysiloxane (TSR-165) 35 Aluminum chelate compound (ALCH) 5 The above ingredients were constantly Varnish A was produced by heating under pressure at 130°C for 60 minutes with stirring.

b Manufacture of solder resist ink A solder resist ink was produced by mixing and homogeneously dispersing the following components using a three-roll mill in a conventional manner.

Part by weight Epoxy acrylate (SP-1509) 30 Dipentaerythrhexaacrylate 20 Neopentyl pivalate glycol diacrylate 15 Barium sulfate 20 Fine silica 2 Gel varnish 5 Phthalocyanine green 3 Dimethylbenzyl ketal 3 Azobisisobutyronitrile 1 Varnish A 30 Total of 2 surfactants 131 c Printing test A sheet-fed offset printing machine equipped with a dry lithographic plate was loaded with the solder resist ink produced by the method described in item b above, and printed directly onto a printed circuit board at a speed of 25 sheets/min. With offset printing and offset printing, more than 2,000 sheets could be printed continuously without causing background smudges.

Next, the obtained printed matter was irradiated with ultraviolet rays using a 5.6 KW three-light type ultraviolet irradiation device with a conveyor speed of 4.5 m/min to obtain a cured coating film with a pencil hardness of 3H or more. When immersed in 1,1,1-trichloroethane (30°C) for 1 hour, there was no blistering, discoloration, or peeling, and it was confirmed that the cured solder resist ink film had sufficient solvent resistance.

After that, the printed circuit board was floated in a 260℃ solder bath for 15 seconds. Only the copper foil other than the printed pattern was solder-coated, and there was no blistering or peeling, and the cured coating of the solder resist ink had sufficient solder heat resistance. It was confirmed that

Manufacturing - Printing Test Example 3 a Production weight part of Varnish A Urethane acrylate (XP-4000B) 40 Epoxy acrylate (SumiFlash A)
40 Aluminum chelate compound (ALCH) 3 Varnish A was produced by heating the above components at 130° C. for 120 minutes with stirring under normal pressure.

b Manufacture of solder resist ink A solder resist ink was produced by mixing the following components in a three-roll mill in a conventional manner and uniformly dispersing them.

Part by weight Polybutadiene acrylate (R-45ACR)
20 Epoxy acrylate (SP-1509) 10 Barium sulfate 30 Pentaerythritol tetraacrylate 15 Polyethylene glycol diacrylate 20 Gel varnish 4 Phthalocyanine green 1 2-ethyl anthraquinone 4 Varnish 50 Surfactant 1 total 151 c Printing test Sheet with dry lithography attached When an offset printing machine was loaded with the solder resist ink manufactured by the method described in item b above and direct printing and offset printing were performed on a flexible printed circuit board at a speed of 20 sheets/min, no scumming occurred. Nini 2000
It was possible to print more than one sheet in succession.

Next, the obtained printed matter was irradiated with ultraviolet rays using a 5.6 KW three-light type ultraviolet irradiation device with a conveyor speed of 4.5 m/min, and a cured coating film with a pencil hardness of 2H or more was obtained.

Next, the substrate with the cured coating film was subjected to a bending test using a 0.5R round bar, and the cured coating film did not suffer any damage such as cracks. Next, when immersed in 1,1,1-trichloroethane (30°C) for 1 hour, there was no blistering, discoloration, or peeling, confirming that the cured solder resist ink film had sufficient solvent resistance. Ta.

After that, the printed circuit board was floated in a 260℃ solder bath for 5 seconds. The solder coated only on the copper foil other than the printed pattern, and there was no blistering or peeling, and the cured coating of the solder resist ink had sufficient solder heat resistance. It was confirmed that

Therefore, it was confirmed that this solder resist ink also has the necessary performance as a dry planographic solder resist ink for flexible circuit boards.

As a comparative example, when an ink was prepared from Manufacturing Printing Example-1 except for Varnish A and printing was carried out in the same manner as Manufacturing Printing Example-1, scumming started to occur from the 10th sheet, and by the 30th sheet, the entire plate surface was Ink adhered to the paper, making it impossible to print.

Claims (1)

[Claims] 1 10 to 80 parts by weight of an ultraviolet curable prepolymer (B) selected from urethane acrylate, polybutadiene acrylate, silicone acrylate, and epoxy acrylate alone or in a mixture, and 20 to 70 parts by weight of the above prelimer (B) alone or in a mixture. 5 to 60 parts by weight of a reaction product (A) of 30 to 80 parts by weight of organopolysiloxane and 1 to 10 parts by weight of an aluminum chelate compound in 100 parts by weight of the ink. Curable printed circuit board solder resist ink composition.