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:
Apr. 19, 2011
Filed:
Apr. 11, 2007
Takahiro Nonaka, Osaka, JP;
Miyoko Ikishima, Osaka, JP;
Noritsugu Daigaku, Osaka, JP;
Masahiro Oura, Osaka, JP;
Masahiko Ando, Osaka, JP;
Takahiro Nonaka, Osaka, JP;
Miyoko Ikishima, Osaka, JP;
Noritsugu Daigaku, Osaka, JP;
Masahiro Oura, Osaka, JP;
Masahiko Ando, Osaka, JP;
Nitto Denko Corporation, Osaka, JP;
Abstract
The present invention relates to a double-sided pressure-sensitive adhesive tape or sheet for wiring circuit board, which comprises a pressure-sensitive adhesive layer formed by a pressure-sensitive adhesive composition containing an acrylic polymer and a chain transfer substance, in which the pressure-sensitive adhesive layer has characteristics that a gel fraction in the initial stage is from 40 to 70% by weight, and a difference between a gel fraction (% by weight) of the pressure-sensitive adhesive layer after the following solder reflow step and the gel fraction (% by weight) of the pressure-sensitive adhesive layer in the initial stage is 10 or less. The solder reflow step satisfies the following heat treatment conditions. Surface temperature of the double-sided pressure-sensitive adhesive tape or sheet reaches 175±10° C. within 130 to 180 seconds, the surface temperature reaches 230±10° C. within 200 to 250 seconds, the surface temperature reaches 255±15° C. within 260 to 300 seconds and the solder reflow step finishes within 370 seconds after start of the solder reflow step for the double-sided pressure-sensitive adhesive tape or sheet.