Toothbrush

Abstract

A toothbrush includes the head portion that is molded from a polyacetal resin having a weight-average molecular weight of 130000 or more. When the head portion is a thin head having a thickness of 3.0 mm or less, a base thickness that corresponds to a thickness of an implantation base is T1 (mm), a hole depth of an implantation hole is U1 (mm), a flat wire implantation depth that corresponds to a depth from an implantation face to an upper end of the flat wire implanted from the implantation face is H1 (mm), and a weight-average molecular weight of the polyacetal resin is Mw, a following equation (1) is satisfied.[Formula 1](−18.5)+T1×7.0+U1×3.5+H1×(−10.0)+MW×0.78×10−5≥2.96  (1)

1 . A toothbrush comprising:
 a head portion having an implantation base provided with implantation holes; and   a bristle bundle implanted in each of the implantation holes of the implantation base by implantation of a flat wire, wherein   the head portion is a thin head that is molded from a polyacetal resin having a weight-average molecular weight of 130000 or more, and has a thickness of 3.0 mm or less, and   when a base thickness that corresponds to a thickness of the implantation base is T 1  (mm), a hole depth of the implantation hole is U 1  (mm), a flat wire implantation depth that corresponds to a depth from an implantation face to an upper end of the flat wire implanted from the implantation face is H 1  (mm), and a weight-average molecular weight of the polyacetal resin is Mw, a following equation (1) is satisfied.
   [Formula 1] 
   (−18.5)+ T 1×7.0+ U 1×3.5+ H 1×(−10.0)+ MW× 0.78×10 −5 ≥2.96  (1)
 
   
     
     
         2 . A toothbrush comprising:
 a head portion having an implantation base provided with implantation holes; and   a bristle bundle implanted in each of the implantation holes of the implantation base by implantation of a flat wire, wherein   the head portion is a thin head that is molded from a polyacetal resin having a weight-average molecular weight of 130000 or more, and has a thickness of 3.0 mm or less, and   when a base thickness that corresponds to a thickness of the implantation base is T 1  (mm), a hole depth of the implantation hole is U 1  (mm), a flat wire implantation depth that corresponds to a depth from an implantation face to an upper end of the flat wire implanted from the implantation face is H 1  (mm), and a weight-average molecular weight of the polyacetal resin is Mw, a following equation (2) is satisfied.
   [Formula 2] 
   (−13.3)+ T 1×6.2+ U 1×2.1+ H 1×(−8.05)+ Mw× 0.36×10 −5 ≥3.33  (2)