Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Compositions to be polymerized by wave energy wherein said...
Reexamination Certificate
2000-03-14
2002-10-15
Seidleck, James J. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Compositions to be polymerized by wave energy wherein said...
C522S101000, C522S103000, C522S170000, C522S181000, C430S269000, C430S270100, C430S280100, C430S281100, C430S286100, C430S287100, C430S288100, C428S416000, C428S413000
Reexamination Certificate
active
06465540
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ultraviolet curable resin composition, which can be used in application fields such as ultraviolet-curable and thermosetting type photo solder resist inks developable with diluted alkaline aqueous solution, pixels, and protective films for color filter, and also a photo solder resist ink using the same ultraviolet curable resin composition, which will be preferably utilized to manufacture printed wiring boards having fine-line, dense conductive pattern.
2. Disclosure of the Prior Art
In the field of printed wiring boards having fine-line, dense conductive pattern, liquid-type photo solder resist inks developable with diluted alkaline aqueous solution are preferably used. For example, Japanese Patent Early Publication No. 61-243869 discloses a photo solder resist ink containing an ultraviolet curable resin developable with a diluted alkaline aqueous solution, photopolymerization initiator, and an epoxy compound. To provide the developability with diluted alkaline aqueous solution, the ultraviolet curable resin has a sufficient amount of carboxyl group.
However, since the photo solder resist ink contains the epoxy compound, a thermosetting reaction between the carboxyl group in the ultraviolet curable resin and the epoxy compound easily occurs under a predrying condition, so that there is a problem that the developability and resolution deteriorate. Due to this reason, an amount used of the epoxy compound is limited within a narrow range, in which the above problem does not occur. As a result, effects of the epoxy compound, i.e., improvements in heat resistance to molten solder, electrical corrosion resistance and so on, are not sufficiently obtained. Thus, the photo solder resist ink of the prior art still has room for improvement.
SUMMARY OF THE INVENTION
Therefore, the present invention is directed to an ultraviolet curable resin composition capable of providing the following advantages.
(1) The resin composition is excellent in developability, resolution, and heat resistance to molten solder.
(2) The resin composition provides a wide developing width. The developing width means a width of predrying condition, in which the developability can be maintained. The developing width is also called a predrying control width or predrying acceptable range.
(3) The resin composition can be used to prepare a photo solder resist ink developable with diluted alkaline aqueous solution, which is capable of providing a solder resist film having an improved adhesion to substrate, excellent electrical corrosion resistance, great heat resistance to molten solder and resistance to gold plating.
That is, the ultraviolet curable resin composition of the present invention includes:
(A) an ultraviolet curable resin obtained by the steps of: polymerizing an ethylenically unsaturated monomer component containing (a) an ethylenically unsaturated monomer having epoxy group and (b) a compound having at least two ethylenically unsaturated groups in one molecule to prepare a copolymer; reacting the copolymer with (c) an ethylenically unsaturated monomer having carboxyl group to prepare a chemical intermediate; and reacting the chemical intermediate with (d) a saturated or unsaturated polybasic acid anhydride;
(B) an epoxy compound having at least two epoxy groups in one molecule;
(C) a photopolymerization initiator; and
(D) a diluent.
It is preferred that the compound (b) is di(meth)acrylate, and particularly di(meth)acrylate having at least one oxyalkylene unit. It is also preferred that an amount of the compound (b) is within a range of 0.1 to 10 mol %, and more preferably 0.1 to 7 mol % with respect to the total amount of the ethylenically unsaturated monomer component used to prepare the copolymer.
In a preferred embodiment of the present invention, the ethylenically unsaturated monomer component further contains (e) an ethylenically unsaturated monomer capable of copolymerizing with the ethylenically unsaturated monomer (a) and the compound (b). In this case, it is possible to suitably adjust the photocurability and properties of a cured film of the resin composition.
It is particularly preferred that the ethylenically unsaturated monomer (a) includes glycidyl (meth)acrylate.
The present invention is also directed to a photo solder resist ink comprising the ultraviolet curable resin composition explained above. Since the resin composition contains the ultraviolet curable resin (A) with the improved heat resistance and softening point, the photo solder resist ink can exhibit excellent developability, resolution, developing width, and heat resistance to molten solder.
The present invention further concerns a predried film obtained by drying the ultraviolet curable resin composition or the photo solder resist ink described above, and a printed wiring board having a cured film of the ultraviolet curable resin composition or the photo solder resist ink described above.
These and still other objects and advantages will become apparent from the following detail descriptions of the preferred embodiments and examples of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[(A) ultraviolet curable resin]
The ultraviolet curable resin composition of the present invention includes an ultraviolet curable resin (A). The ultraviolet curable resin (A) is prepared by the following steps. First, an ethylenically unsaturated monomer component containing (a) an ethylenically unsaturated monomer having epoxy group and (b) a compound having at least two ethylenically unsaturated groups in one molecule is polymerized to obtain a copolymer. Then, the copolymer is reacted with (c) an ethylenically unsaturated monomer having carboxyl group to obtain a chemical intermediate. In addition, the chemical intermediate is reacted with (d) a saturated or unsaturated polybasic acid anhydride to obtain the ultraviolet curable resin (A).
<(a) ethylenically unsaturated monomer having epoxy group>
The principal purpose of compounding the ethylenically unsaturated monomer (a) is to introduce epoxy group into the copolymer, and provide photocurability based on ethylenically unsaturated double bond to the copolymer when the copolymer is reacted with the ethylenically unsaturated monomer (c) having carboxyl group. Therefore, the photocurability of the ultraviolet curable resin (A) depends on an amount of the ethylenically unsaturated monomer (a) used to prepare the copolymer. In the present invention, it is preferred that the amount of the ethylenically unsaturated monomer (a) is within a range of 40 to 99.9 mol %, and more preferably 55 to 95 mol % with respect to a total amount of the ethylenically unsaturated monomer component used to prepare the copolymer. When the amount is less than 40 mol %, the photocurability may become poor, and sufficient sensitivity and resolution for patterning may not be obtained. In addition, when a solder resist is formed by use of a photo solder resist ink including the ultraviolet curable resin composition of the present invention, some properties of the solder resist such as heat resistance to molten solder may become insufficient. When the amount is within the range of 55 to 95 mol %, the solder resist exhibits further improved heat resistance to molten solder and electrical corrosion resistance.
As the ethylenically unsaturated monomer (a), for example, it is possible to use glycidyl (meth)acrylate, epoxy cyclohexyl derivative of (meth)acrylic acid such as (3, 4-epoxy cyclohexyl)methyl (meth)acrylate, alicyclic epoxy derivative of (meth)acrylate, &bgr;-methyl glycidyl (meth)acrylate or dipropylene glycol di(meth)acrylate. The ethylenically unsaturated monomer (a) can be one of these materials or a combination of two or more of these materials. In particular, it is preferred to use glycidyl (meth)acrylate.
In the present specification, “(meth)acrylic acid” means “acrylic acid” and “methacrylic acid”, and “(meth)acrylic-” means “acrylic-” and “methacrylic-”.
<(b) compound having at least two ethyleni
Fujimoto Masatoshi
Hashimoto Soichi
Kubo Tatsuya
Goo Chemical Co., Ltd.
McClendon Sanza L.
Rader & Fishman & Grauer, PLLC
Seidleck James J.
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