Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phenol – phenol ether – or inorganic phenolate
Reexamination Certificate
2000-08-17
2002-01-01
Hampton-Hightower, P. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From phenol, phenol ether, or inorganic phenolate
C528S045000, C528S065000, C528S075000, C528S353000, C528S173000, C528S176000, C525S422000, C525S434000, C525S436000, C525S440030, C428S458000
Reexamination Certificate
active
06335417
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a modified polyimide resin which is useful in imparting reduced shrinkage upon setting to a thermosetting resin composition and also useful in imparting heat resistance and pliability and the like to a hardened article of such thermosetting resin composition (hardened resin), and to a thermosetting resin composition containing the same, as well as to a film carrier comprising a surface protection film formed by coating an overcoat agent containing such composition as the main component followed by setting it, and to a carrier device employing such film carrier.
BACKGROUND ART
The surface protection films of flexible wiring circuits have heretofore been produced, e,g., by a method in which a polyimide film called a coverlay film is punched with a metal template having a certain pattern and then bound with an adhesive or a method in which an overcoat agent containing as the main component a UV setting resin imparted with a flexibility or a thermosetting resin is applied by a screen printing and then allowed to set. However, since a coverlay film method has a disadvantage in terms of an processability and a method employing an overcoat agent involves a problematic warping upon setting as well as a poor pliability of a hardened resin, there is still no method for forming a surface protective film for a flexible wiring circuit substrate whose performance satisfies all requirements.
On the other hand, the so-called TAB method employing a film carrier suitable in imparting a higher density and a less thickness to a liquid crystal-driving IC package, has got increasingly employed recently. A basic structure of a film carrier is mainly composed of a heat-resistant, insulating film substrate, such as one made from a polyimide, and an electrical conductor such as copper foil, bound thereto via an adhesive whose main component is an epoxy-based resin, the wiring pattern having been formed on the copper foil by etching. Afilm carrier device is made by connecting an IC to a film carrier (referred to also as a tape carrier) followed by confining with the use of a confining resin, and the film carrier is generally covered with a surface protecting film from an overcoat agent for the purpose of preventing reduction in reliability due to the occurrence of a pattern short, erosion, migration, whiskering and the like during the step before connecting an IC. While an overcoat agent employed for a film carrier has been an epoxy-based one or a polyimide-based one, the former has not been satisfactory because of warping upon setting and a poor pliability of the resultant film, and the latter has not been satisfactory in terms of adherence to an IC confining resin and a processability, resulting in the fact that two or more overcoat agent have been employed to compensate each other for their shortages (JP-A 6-283575).
Under the circumstance of the prior art described above, an object of the present invention is to provide a resin composition capable of fully satisfying the requirements with regard to the characteristics of an overcoat agent for a wiring circuit which should be pliable, such as a flexible wiring circuit substrate and a film carrier.
DISCLOSURE OF THE INVENTION
We have made an effort to solve the problems described above, and finally discovered that a modified polyimide resin having a polybutadiene skeleton represented by Formula (4) shown below is extremely useful as a component of an overcoat agent for a flexible wiring circuit substrate and a film carrier, more specifically, that a thermosetting resin composition obtained by mixing a polybutadiene polyol having a number average molecular weight of 1,000 to 8,000 and 2 to 10 hydroxyl groups per molecule (Component A), a modified polyimide resin represented by Formula (4) shown below (Component B) and a polybutadiene polyblock isocyanate having a number average molecular weight of 1,000 to 8,000 and 2 to 10 hydroxyl groups per molecule (Component C) at a certain ratio, can serve as a resin composition for an overcoat which has a performance capable of satisfying the requirements with regard to various characteristics, including reduced shrinkage upon setting, and pliability, tight adherence, electric insulation, chemical resistance and heat resistance of a hardened article, thus establishing the present invention.
wherein R
1
represents the residue obtainable by removing all the carboxyl groups from an organic compound having 4 carboxyl groups (tetrabasic acid), R
2
represents the residue obtainable by removing all the isocyanate groups from an organic compound having 2 isocyanate groups, and R
3
represents the residue obtainable by removing the hydroxyl group from a hydroxyl-terminal polybutadiene; L2 and M2 represent the ratio of the number the component polybutadiene units and the ratio of the number of the component polyimide units, respectively, to the total number of both the kinds of units and n3 represents a degree of polymerization, provided that L2+M2=1,0<L2<1,0<M2<1 and 1≦n3≦1,000 simultaneously.
Accordingly, the present invention relates, firstly, to a modified polyimide resin obtainable by reacting the following three (3) kinds of compounds, i.e., a bifunctional hydroxyl-terminal polybutadiene having a number average molecular weight of 800 to 5,000 (Compound a), a tetrabasic acid dianhydride represented by Formula (1) (Compound b):
wherein
R
1
represents the residue obtainable by removing all the carboxyl groups from an organic compound having 4 carboxyl groups, and a diisocyanate compound (Compound c), said modified polyimide resin being represented by Formula (2):
wherein
R
1
represents the residue obtainable by removing all the carboxyl groups from an organic compound having 4 carboxyl groups, R
2
represents the residue obtainable by removing all the isocyanate groups from an organic compound having 2 isocyanate groups, and R
3
represents the residue obtainable by removing the hydroxyl group from a hydroxyl-terminal polybutadiene; L1 and M1 represent the ratio of the number of the component polybutadiene units and the ratio of the number of the component polyimide units, respectively, to the total number of both the kinds of units and n1 represents a degree of polymerization, provided that L1+M1=1,0<L1<1,0<M1<1 and 1≦n1≦10,000 simultaneously.
The present invention relates also to various modified polyimide resins obtainable by specifying inter alia amounts of the starting materials for their synthesis. There may be mentioned as such modified polyimide resins, e.g., a first modified polyimide resin represented by Formula (2) shown above, and obtainable by reaction between an isocyanate group-containing product (Starting material 1, isocyanate equivalent number:X equivalent(s)) which can be obtained by reacting a bifunctional hydroxyl-terminal polybutadiene having a number average molecular weight of 800 to 5,000 (Compound a) with a diisocyanate compound (Compound c) at a hydroxyl groups:isocyanate groups ratio of 1:1.5 to 2.5 in terms of equivalent number, and a tetrabasic acid dianhydride represented by Formula (1) shown above (Starting material 2, acid anhydride equivalent number: Y equivalent(s)), the isocyanate-group containing product being represented by Formula (3):
wherein
R
2
represents the residue obtainable by removing all the isocyanate groups from an organic compound having 2 isocyanate groups, and R
3
represents the residue obtainable by removing the hydroxyl group from a hydroxyl-terminal polybutadiene; n2 represents a degree of polymerization, provided that 0≦n2≦100; a second modified polyimide resin represented by Formula (4) shown above and obtainable by reaction between Starting materials 1 and 2 in amounts in terms of equivalent numbers satisfying Y>X≧Y/3,0<X and 0<Y simultaneously in the above reaction; a third modified polyimide resin represented by Formula (2) shown above, and obtainable by reacting a modified polyimide resin represented by Formula (4) shown
Orikabe Hiroshi
Yokota Tadahiko
Ajinomoto Co. Inc.
Hampton-Hightower P.
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