Fiber package
An object of the present invention is to provide a fiber package in which a partially split carbon fiber bundle is wound around a bobbin, and which has no problem in unwindability. A fiber package is provided, which is a square-end type fiber package formed by traverse winding a fiber bundle ( 12 ) around a bobbin, in which the fiber bundle ( 12 ) is partially split into sub-bundles ( 11 ), and the width W of the fiber bundle ( 12 ) is smaller than the total sum of the widths W S of the sub-bundles ( 12 ). A fiber package is also provided, which is a square end type fiber package formed by traverse winding a fiber bundle ( 12 ) around a bobbin, in which the fiber bundle ( 12 ) is partially split into sub-bundles ( 11 ) and is wound around the bobbin so as to cause the sub-bundles ( 11 ) to overlap each other.
1 . A fiber package, which is a square end type fiber package formed by traverse winding a carbon fiber bundle around a bobbin,
wherein the carbon fiber bundle is partially split into sub-bundles in a longitudinal direction of the carbon fiber bundle and is wound around the bobbin so as to cause the sub-bundles to overlap each other,
a width of the carbon fiber bundle is smaller than a total sum of widths of the sub-bundles,
the carbon fiber bundle has more than one slit rows, and each of the slit rows includes a plurality of slits in the longitudinal direction, and
the plurality of slits satisfies L S /(L S +L G ) of 90% or more, in which L S is a slit length of each of the plurality of slits, and L G is a gap length between the plurality of slits adjacent to each other.
2 . The fiber package according to claim 1 , wherein the width of the carbon fiber bundle is 90% or less of the total sum of widths of the sub-bundles.
3 . The fiber package according to claim 1 , wherein between sections of the carbon fiber bundle wound around the bobbin in consecutive traverse cycles that are not separated by 5 cycles or more, the positions of center lines are shifted at least by a shift width of 0.8 or more times the width of the carbon fiber bundle.
4 . The fiber package according to claim 3 , wherein between sections of the carbon fiber bundle wound around the bobbin in consecutive traverse cycles that are not separated by 5 cycles or more, the positions of center lines are shifted at least by a shift width of 1.0 or more times the width of the carbon fiber bundle.
5 . The fiber package according to claim 4 , wherein between sections of the carbon fiber bundle wound around the bobbin in consecutive traverse cycles that are not separated by 5 cycles or more, the positions of center lines are shifted at least by a shift width of 1.3 or more times the width of the carbon fiber bundle.
6 . The fiber package according to claim 1 , wherein the carbon fiber bundle is partially split into three or more sub-bundles.
7 . The fiber package according to claim 1 , wherein the number of filaments of the sub-bundles is 5000 or less.
8 . The fiber package according to claim 1 , wherein the total number of filaments of the carbon fiber bundle is 12000 or more.
9 . The fiber package according to claim 1 , wherein the width of the carbon fiber bundle is 86% or less of the total sum of widths of the sub-bundles.
10 . The fiber package according to claim 1 , wherein the traverse winding has a relationship represented by formula below:
R w =2 L T /(π D tan θ)
wherein Rw is a winding ratio,
Lt is a traverse length,
D is a winding diameter, and
θ is a lead angle.
11 . A method for producing the fiber package according to claim 1 , the method comprising:
partially splitting the carbon fiber bundle into the sub-bundles; and
winding the carbon fiber bundle that has been partially split into the sub-bundles around the bobbin,
wherein in the winding, the carbon fiber bundle is wound around the bobbin such that the width of the carbon fiber bundle is smaller than the total sum of widths of the sub-bundles.
12 . A method for producing the fiber package according to claim 1 , the method comprising:
partially splitting the carbon fiber bundle into the sub-bundles; and
winding the carbon fiber bundle that has been partially split into the sub-bundles around the bobbin,
wherein in the winding, the carbon fiber bundle is wound around the bobbin so as to cause the sub-bundles to overlap each other.
13 . The method according to claim 10 , wherein in the winding, the carbon fiber bundle is wound around the bobbin such that the width of the carbon fiber bundle is 90% or less of the total sum of the widths of the sub-bundles.
14 . The method according to claim 10 , wherein in the winding, between sections of the carbon fiber bundle wound around the bobbin in consecutive traverse cycles that are not separated by 5 cycles or more, the positions of center lines are shifted at least by a shift width of 0.8 or more times the width of the carbon fiber bundle.
15 . The method according to claim 13 , wherein in the winding, between sections of the carbon fiber bundle wound around the bobbin in consecutive traverse cycles that are not separated by 5 cycles or more, the positions of center lines are shifted at least by a shift width of 1.0 or more times the width of the carbon fiber bundle.
16 . The method according to claim 14 , wherein in the winding, between sections of the carbon fiber bundle wound around the bobbin in consecutive traverse cycles that are not separated by 5 cycles or more, the positions of center lines are shifted at least by a shift width of 1.3 or more times the width of the carbon fiber bundle.
17 . The method according to claim 10 , wherein in the splitting step, the carbon fiber bundle is partially split into three or more sub-bundles.
18 . The method according to claim 10 , wherein the number of filaments of the sub-bundle is 5000 or less.
19 . The method according to claim 10 , wherein the total number of filaments of the carbon fiber bundle is 12000 or more.