Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2002-02-08
2004-06-01
Sanders, Kriellion A. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C524S138000, C524S148000, C428S416000, C428S457000, C525S450000, C525S467000
Reexamination Certificate
active
06743841
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a heat-resistant composition having excellent flame resistance useful as an adhesive, a coating material or an ink.
2. Description of the Prior Art
Solvent-soluble polyimide having excellent heat resistance is utilized as a heat-resistant coating material or a heat-resistant adhesive, which is essential for manufacturing an electronic component or a printed wiring board.
In order to use such solvent-soluble polyimide, however, some problems must be solved. More specifically, the solvent-soluble polyimide must be improved in solubility in a low-boiling solvent, heat resistance and the like.
In relation to the improvement in solubility in a low-boiling point, general solvent-soluble polyimide is dissolved only in N-methyl-2-pyrolidone or sulfolane, which is a high-boiling solvent requiring drying at a high temperature to be removed in coating. This drying must industrially disadvantageously be performed under a nitrogen atmosphere, in order to suppress deterioration of the resin. If the solvent-soluble polyimide is used while the solvent still remains, the characteristics thereof etc. are reduced due to moisture adsorption.
In relation to the improvement in heat resistance, the aforementioned solvent-soluble polyimide is already completely rendered imidic to have thermoplasticity in general. However, the thermoplastic solvent-soluble polyimide tends to abruptly cause thermal deformation in a temperature region exceeding the glass-transition temperature (Tg). Thus, the glass-transition temperature of the employed polyimide must be sufficiently higher than the required heat resistance, leading to requirement for a material having higher heat resistance.
Some methods of solving the aforementioned problems are known in general. As to the improvement in solubility in a low-boiling solvent, for example, an alicyclic component or an aliphatic component is generally introduced into polyimide resin for imparting solubility in a low-boiling solvent, in order to attain milder drying conditions. In this method, however, heat resistance and flame resistance of the polyimide resin are disadvantageously reduced. As to the improvement in heat resistance, a stiffer component must be employed for imparting higher heat resistance. In this case, however, solvent solubility is reduced and hence it is difficult to compatibly improve the heat resistance and the solubility in a low-boiling solvent. While a cross-linkable component such as epoxy resin may be employed for improving the heat resistance, the cross-linkable component itself is inflammable and reduces the flame resistance of the polyimide resin composition. In order to compatibly improve the solubility in a low-boiling solvent and the heat resistance while maintaining flame resistance, therefore, the polyimide resin must be employed along with a flame retardant.
In relation to the flame retardant, a phosphorus compound such as phosphate or inorganic hydroxide such as aluminum hydroxide is known in general. However, the compound such as phosphate, generally having a low melting point and a low boiling point as well as low compatibility with polyimide resin, reduces adhesiveness of the polyimide resin due to exudation of the flame retardant. As to adhesiveness under a high temperature, it is known that the phosphorus compound is liquefied or vaporized to reduce adhesiveness particularly under a high temperature and after high-temperature treatment or cause blistering. On the other hand, the inorganic hydroxide must be mixed into the heat-resistant composition in a large quantity in order to impart sufficient flame resistance, leading to reduction of characteristics such as adhesiveness, flexibility and hygroscopicity.
As hereinabove described, there has been obtained no satisfactory halogen-free polyimide heat-resistant composition having solubility in a low-boiling solvent, heat resistance, flame resistance, adhesiveness and mechanical properties under the present circumstances.
SUMMARY OF THE INVENTION
In order to solve the aforementioned problems, an object of the present invention is to provide a halogen-free polyimide heat-resistant composition having solubility in a low-boiling solvent, heat resistance, flame resistance, adhesiveness and mechanical properties.
The heat-resistant composition according to the present invention contains solvent-soluble polyimide resin (A) and a phosphazene compound (B). The said phosphazene compound (B) includes at least either a cyclic phenoxyphosphazene compound (B1) expressed in the following chemical formula (1):
where m represents an integer of 3 to 25 and Ph represents a phenyl group, or a chain phenoxyphosphazene compound (B2) expressed in the following chemical formula (2):
where X
1
represents group-N═P(OPh)
3
or group-N═P(O)OPh, Y
1
represents group-P(OPh)
4
or group-P(O)(OPh)
2
, n represents an integer of 3 to 10,000 and Ph represents a phenyl group,
or a cross-linked phenoxyphosphazene compound (B3) cross-linked by a cross-linking group including at least one of an o-phenylene group, an m-phenylene group, a p-phenylene group and a bisphenylene group expressed in the following chemical formula (3):
where A represents —C(CH
3
)
2
—, —SO
2
—, —S— or —O— and a represents 0 or 1, with respect to the phosphazene compound including at least either the said cyclic phenoxyphosphazene compound (B1) or the said chain phenoxyphosphazene compound (B), so that the said cross-linking group intervenes between two oxygen atoms desorbed by the said phenyl group of the phosphazene compound and the phenyl group content is 50 to 99.9% with reference to the total number of phenyl groups contained in the said phosphazene compound including at least either the said cyclic phenoxyphosphazene compound (B1) or the said chain phenoxyphosphazene compound (B2) with no free hydroxyl groups in molecules.
The heat-resistant composition according to the present invention is characterized in that the said polyimide resin (A) is polyimide resin, containing a solvent solubility imparting component selected from at least one of an aliphatic compound component, an alicyclic compound component and an alkylene oxide adduct component of a bisphenol compound, soluble in a solvent containing a low-boiling solvent.
The heat-resistant composition according to the present invention can contain a reactive compound (C) selected from at least one of an epoxy compound, an acrylic compound and an isocyanate compound.
The heat-resistant component according to the present invention is characterized in that the said polyimide resin (A) is polyamide imide resin and the said reactive compound (C) is an epoxy compound.
The heat-resistant composition according to the present invention is characterized in that the said polyimide resin (A) is polyester imide resin and the said reactive compound (C) is an epoxy compound.
The heat-resistant composition according to the present invention is characterized in that the said polyimide resin (A) is polyether imide resin and the said reactive compound (C) is an epoxy compound.
The present invention is also directed to an adhesive for a printed wiring board employing the said heat-resistant composition.
The present invention is also directed to an adhesive sheet for a printed wiring board employing the said heat-resistant composition.
The present invention is also directed to a multilayer printed wiring board employing the said heat-resistant composition.
The present invention is also directed to a sealant for a printed wiring board employing the said heat-resistant composition.
The present invention is also directed to an insulating circuit protective film for a printed wiring board employing the said heat-resistant composition.
The present invention is also directed to a circuit protective agent employing the said heat-resistant composition.
The present invention is also directed to a cover-lay film employing the said heat-resistant composition.
The present invention is also directed to a cover ink employing
Shimizu Toshiyuki
Tada Yuji
Leydig , Voit & Mayer, Ltd.
Sanders Kriellion A.
Toyo Boseki Kabushiki Kaisha
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