The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 01, 2010
Filed:
Aug. 31, 2006
Tomoharu Kurita, Ohtsu, JP;
Shinji Suzuki, Ohtsu, JP;
Cyuji Inukai, Ohtsu, JP;
Toyo Boseki Kabushiki Kaisha, Osaka, JP;
Abstract
The present invention provides a non-halogen polyamide-imide resin soluble in an amide solvent at a concentration of 10%, the resulting varnish, when stored at 5° C. for 1 month, exhibiting a solution viscosity change ((solution viscosity after 1 month−initial solution viscosity)/initial solution viscosity), expressed as an absolute value, of not greater than 3.0, and the resin having a moisture absorption (25° C., 90% RH, 24 hours) of not greater than 2.0%; a flexible metal-clad laminates using such a resin; and a flexible printed wiring board prepared from such a flexible metal-clad laminate by circuit formation. The flexible metal-clad laminate of the invention does not curl under any conditions, including humid conditions, and exhibits excellent dimensional stability since the heat resistant resin used as an insulation material has low moisture absorption and low thermal expansion coefficient and there is less internal stress in the flexible metal-clad laminate. Moreover, since the solder heat resistance and the insulation properties are not impaired even after humidification and since the heat resistant resin is soluble in organic solvents with high solution stability, the flexible metal-clad laminate of the invention can be inexpensively produced.