US 11,858,072 B2
Flux, flux-cored solder using flux, flux-coated solder using flux and soldering method
Yoko Kurasawa, Tokyo (JP); Hiroaki Iseki, Tokyo (JP); and Kenta Nakajima, Tokyo (JP)
Assigned to SENJU METAL INDUSTRY CO., LTD., Tokyo (JP)
Appl. No. 17/623,668
Filed by SENJU METAL INDUSTRY CO., LTD., Tokyo (JP)
PCT Filed Feb. 1, 2021, PCT No. PCT/JP2021/003465
§ 371(c)(1), (2) Date Dec. 29, 2021,
PCT Pub. No. WO2021/199645, PCT Pub. Date Oct. 7, 2021.
Claims priority of application No. 2020-059856 (JP), filed on Mar. 30, 2020.
Prior Publication US 2022/0203483 A1, Jun. 30, 2022
Int. Cl. B23K 35/36 (2006.01); B23K 35/362 (2006.01); B23K 35/365 (2006.01); B23K 35/368 (2006.01)
CPC B23K 35/3613 (2013.01) [B23K 35/362 (2013.01); B23K 35/365 (2013.01); B23K 35/368 (2013.01)] 15 Claims
 
1. A flux comprising:
a rosin methyl ester,
an unesterified rosin and,
an activator which includes an organic halogen compound activator,
wherein a content of the rosin methyl ester is 0.5% to 20% by mass with respect to a total mass of the flux,
wherein a content of the unesterified rosin is 73% to 98.9% by mass with respect to the total mass of the flux,
wherein the flux is solid at 25° C. or is solid-like having a viscosity η1 at 25° C. of 3,200 Pa·s or more when the viscosity is measured by the steps comprising:
sandwiching the flux between parallel flat plates of a rheometer and deforming by narrowing a space between the parallel flat plates while heating at 100° C.
thereby forming a thin sample of the flux having a thickness of 0.5 mm,
cooling the thin sample to 25° C.,
rotating the parallel flat plates of the rheometer at 6 Hz;
measuring the viscosity η1 at 25° C. 5 minutes after rotating parallel flat plates; and
wherein the flux is used for an inside of a flux-cored solder or an exterior of a flux-coated solder.