JPH0132868B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a photocurable ink composition, and in particular to a photocurable ink composition for screen printing used to form permanent protective masks such as solder resists and plating masks in the production of printed wiring boards. It depends. When manufacturing printed wiring boards, conventionally, permanent protective masks for solder resist and plating were used.
It has been formed by applying an ink composition containing an epoxy resin, a urea resin, an alkyd resin, a melamine resin, or a modified resin thereof as a main component by a screen printing method, and then heating and curing the ink composition. These ink compositions contain 5 to 50% organic solvent.
Furthermore, in the case of modified resins, formaldehyde is produced as a by-product during condensation and polymerization, so the odor and impact on the health of workers cannot be ignored, and there is a risk of air pollution. . Moreover, during the hardening process, high temperatures of 120 to 160℃ and 10%
Since it requires a heating time of 40 minutes to 40 minutes, productivity is low, and in addition, there is a possibility that shrinkage, warping, and characteristic deterioration of the printed wiring board may occur. In order to overcome these deficiencies, photocurable ink compositions containing prepolymers of bisphenol A type epoxy acrylate and novolak type epoxy acrylate as main components were developed as solder resist inks and have been put to practical use in the production of printed wiring boards. I have reached the point where However, these solder resist inks have problems in heat resistance, adhesion, and chemical resistance.
That is, the actual situation is that the resist tends to bulge or peel off during the soldering process after inserting electronic components, and when used as a permanent protective mask for plating, it tends to peel off after plating. Therefore, an object of the present invention is to provide a solvent-free type product that is excellent in heat resistance, adhesion, chemical resistance, and electrical properties, and that is suitable for forming permanent protective masks for solder resists and plating. An object of the present invention is to provide a suitable photocurable ink composition. According to the present invention, this object is achieved by: (a) component A consisting of at least one resin obtained by acrylating or methacrylating bismaleimide/triazine resin; and (b) bisphenol A type epoxy resin, novolak type epoxy resin. Component B consisting of at least one resin, urethane resin, polyester resin, or acrylated or methacrylated resin, and (c) component C consisting of at least one photopolymerizable monomer.
A photo-curable ink, the main component of which is A:B=5:95 to 95:5 (A+B):C=10:90 to 70:30. This is achieved by the composition. The specific blending ratio of components A, B, and C is determined by considering the properties of the substances selected as these components, but component A mainly contributes to improving heat resistance, chemical resistance, and electrical properties. Component B contributes to photocurability and adhesion, and component C contributes to photocurability, adhesion, and viscosity adjustment for printability. The acrylated or methacrylated bismaleimide/triazine resin (referred to as "BT resin") in component A is "BT
-3401" and "BT-3109" can be used. Among the B components, acrylated or methacrylated bisphenol A type epoxy resins include "SP-1506", "SP-1507", "SP-
1509”, “V-5502”, “VR-60X”, “VR-77X”,
Those commercially available under the trade names "VR-90X", "UE-8200", "X-63-101", etc. can be used, and as acrylated or methacrylated volac type epoxy resins, “SP-
4010'', ``SP-4050'', ``UE・EXP250'', ``SumiFlash A'', and ``SumiFlash B'' can be used, and acrylated or methacrylated urethane resins can be used. For example, "W-896", "#783",
"#893", "XP-7000B", "XP-4200B", "M-
1100X”, “KKS-1010”, “EXP-1570A”,
"EXP-1572A", "#6008", "#6173", "B-
3672-40”, “TS-3552-5”, “ULB-20GA”
As acrylated or methacrylated polyester resins, commercially available products can be used, such as "Atrazku 382A", "Viscoat 2000", "Viscoat", etc.
3000”, “EBECRYL510”, “EBECRYL550”,
Those commercially available under the trade names "EBECRYL810" and "Fotomer 5007" can be used, and as the acrylated or methacrylated polybutadiene resin, "R-
45ACR" and "Quinbeam 101" can be used. The photopolymerizable monomer that is component C includes ethylene glycol diacrylate, ethylene glycol dimethacrylate, polyethylene glycol acrylate, polyethylene glycol methacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, neopentyl glycol acrylate, and neopentyl glycol acrylate. Pentyl glycol methacrylate, 1,6-
Hexanediol diacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, β-hydroxyalkyl acrylate, β-hydroxyalkyl methacrylate, triallyl cyanurate, triallyl isocyanate Nurate, diallyl phthalate, diallyl isophthalate, melamine acrylate, butoxyethyl acrylate, stearyl acrylate, lauryl acrylate, tetrahydroxy acrylate, tetrahydroxy methacrylate, aminoalkyl acrylate, aminoalkyl methacrylate, triethylene glycol diacrylate, triethylene glycol diacrylate Methacrylate, dipropylene glycol diacrylate, pentaerythritol triacrylate,
pentaerythritol trimethacrylate,
1,5-pentadiol diacrylate, isobornyl acrylate, glycerol diacrylate, glycerol dimethacrylate, glycerol acroxy dimethacrylate, ethyl carbitol acrylate, methyl triglycol acrylate, 2-hydroxyethyl acryloyl phosphate, N- Vinyl-2-pyrrolidone, acrylamide, N-methylol acrylamide, N-n-butoxymethyl acrylamide,
Ethylenically unsaturated compounds such as N-(1,1-dimethyl-3-oxobutyl)acrylamide and itaconic acid can be used. The ink composition according to the present invention includes the above A, B and C.
In addition to the ingredients, thioxanthone, benzoin, benzoin alkyl ether, xanthone, dimethylxanthone, benzophenone, anthracene, 2,2-diethoxyacetophenone, benzyl dimethyl ketal, benzyl, diphthalate are used as photosensitizers for curing with light. enyl disulfide, anthraquinone, 1-chloroanthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone, methylanthraquinone, 1-chloromethylnaphthalene, N,N'-tetraethyl-4,4'-diaminobenzophenone, It contains dibenzosbalone, 1,1-dichloroacetophenone, etc. singly or in combination, and these photosensitizers are contained in an amount of 0.2 to 8 parts by weight (based on the entire ink composition).
100 parts by weight). To accelerate curing, triethanolamine, 2
- 0.05 to 3 parts by weight of tertiary amines such as dimethylaminoethanol, dimethylaminobenzoic acid, isoamyl dimethylaminobenzoate, dioctylaminobenzoic acid, and lauryl dimethylaminobenzoate (based on the total ink composition as 100 parts by weight) case)
It can be used at a rate of Furthermore, in cases where it is expected that the curing time will be longer or the curing will be insufficient with light alone, such as in the case of thick films, azobisbutylnitrile or phenyl may be used to accelerate curing with heat rays. Azotriphenylmethane, 1,1-azobis-1-cyclohexanenitrile, azobisisobutyramidine, 2-cyano-2-propylazoformamide, azobis-2-4-dimethylvaleronitrile, 1,1-azobisquiumene, and azobis −
Azo compounds such as 4-methoxy-2,4-dimethylvaleronitrile, methyl ethyl ketone peroxide, cyclohexane peroxide,
3,3,5-trimethylcyclohexane peroxide, acetylacetone peroxide, t-
Butyl hydroperoxide, quinene hydroperoxide, diquinyl peroxide,
Organic peroxides such as acetyl peroxide, acetylcyclohexylsulfonyl peroxide, 1,1-bis(t-butylperoxy)3,3,5-trimethylcyclohexane, and t-butylperoxybenzoate in an amount of 0.1 to 5% by weight parts (when the entire ink composition is 100 parts by weight). However, when using these heat-sensitive curing accelerators, the pot life of the ink composition may be shortened, so it is necessary to pay attention to this point. The ink composition according to the present invention may further contain an extender pigment or a colored pigment, and the extender pigments include barium sulfate, talc, calcium carbonate, bentonite, fine silica, clay, kaolin, asbestos, diatomaceous earth, etc. can,
Color pigments include phthalocyanine green, phthalocyanine blue, titanium oxide, titanium yellow, bisazo yellow, yellow lead, Hansa yellow,
Organic or inorganic pigments such as Lake Red C, Brilliant Carmine 6B, Vulcan Orange, Chrome Permillion, Carbon Black, etc. can be used. Furthermore, the ink composition according to the present invention may contain a polymerization inhibitor, a thickener, a thixotropic agent, a leveling agent,
Additives such as antifoaming agents and adhesion agents can be used in a manner known per se. Examples and Reference Examples (A) Preparation of Ink Compositions Ink compositions were prepared by uniformly dispersing various components at the compounding ratios shown in Tables 1 and 2 below using a three-roll mill at room temperature in a conventional manner. (B) Formation of a cured film A printed wiring board (150 x 250 mm) on which a circuit was formed by etching was coated with each ink composition obtained in the examples and reference examples shown in Tables 1 and 2 below. Screen printing was performed using a Tsushi screen plate, and the printed film was cured by processing with an 80W triple-lamp high-pressure mercury lamp at an irradiation distance of 25 cm and a conveyor speed of 3 m/min. (C) Curing test method for cured film (i) Adhesion Based on Japanese Industrial Standard D-0202. A tape peeling test was performed after cross-cutting at 1 mm intervals, and the results are expressed as the remaining area of the film. (ii) Pencil hardness According to Japanese Industrial Standard K-5400. Load 1Kg done using pencil hardness tester
Indicates the hardness of time. (iii) Bulging after soldering The sample surface coated with post flux was
Float for 20 seconds in a solder bath at °C for soldering, then wash the post-flux residue with trichloroethane, apply adhesive tape, and peel off the tape sharply in the right angle direction to remove the film on the copper surface. Inspect and indicate the number of peeled areas (total number of 10 samples). (iv) Adhesion after soldering The results of the adhesion test according to item (i) above after soldering and cleaning in the manner described in item (iii) above are shown. (v) Hydrochloric acid resistance The results of the adhesion test according to the above item (i) are shown after immersing the sample in a 10% by volume aqueous hydrochloric acid solution at 40°C for 1 hour, taking it out, washing it with water, and drying it. (vi) Sodium hydroxide resistance The results of the adhesion test according to item (i) above are shown after immersing the sample in a 5% by weight aqueous sodium hydroxide solution at 40°C for 30 minutes, taking it out, washing it with water, and drying it. (vii) Acetone resistance The results of the adhesion test according to item (i) are shown after immersing the sample in an acetone solution at 40°C for 2 hours, taking it out, and drying it. (viii) Insulation resistance According to Japanese Industrial Standard Z3197. The results are shown below, which were measured using an insulation resistance meter TR-8601 manufactured by Takeda Riken after being coated on a comb-shaped electrode made of a G-10 copper-clad laminate using a printing method and cured. (ix) Dielectric dissipation tangent The following is the result of measurement of the sample described in item (viii) above using an automatic capacitance bridge 4270A manufactured by Yokogawa Huret Packard. The prepolymers used in Examples and Reference Examples were commercially available and were as follows. Example 1 Bisphenol type epoxy acrylate
SP-1507 Urethane acrylate EXP-1572A Example 2 Novolac type epoxy acrylate SP-4050 Polyester acrylate Viscoat 2000 Reference example 1 Bisphenol type epoxy acrylate
VR-90X Reference example 2 Novolac type epoxy acrylate SP-4010 Reference example 3 Bisphenol type epoxy acrylate
VR-90X Novolac type epoxy acrylate SP-4010 Urethane acrylate EXP-1572A

【table】

【table】

【table】

[Table] As judged from the above table, if bisphenol type epoxy acrylate is used alone as the prepolymer (Reference Example 1), the adhesion of the resulting film is good, but the soldering heat resistance and chemical resistance are poor. problems occur, and the electrical characteristics are also poor. On the other hand, if novolac type epoxy acrylate is used alone (Reference Example 2),
Good solder heat resistance and chemical resistance, but poor adhesion. Therefore, if a bisphenol type epoxy acrylate and a urethane acrylate are used in combination with the novolac type epoxy acrylate (Reference Example 3), the adhesion is improved, but the soldering heat resistance is slightly lowered. In other words, it is difficult for ink compositions with known formulations to achieve both adhesion and other properties, particularly soldering heat resistance. On the other hand, according to the ink composition of the present invention (Examples 1 to 2), heat resistance, chemical resistance, and electrical properties can be improved without impairing adhesion by using an acrylate of BT resin. It can be seen that an excellent film can be formed.

Claims (1)

[Scope of Claims] 1 (a) A component consisting of at least one resin obtained by acrylating or methacrylating a bismaleimide/triazine resin; (b) a bisphenol A type epoxy resin, a novolac type epoxy resin, (c) Component B consisting of at least one type of resin obtained by acrylating or methacrylating urethane resin, polyester resin, or polybutadiene resin, and (c) component C consisting of at least one type of photopolymerizable monomer.
A photo-curable ink, the main component of which is A:B=5:95 to 95:5 (A+B):C=10:90 to 70:30. Composition.